• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a distance measuring method using a light source (LS) and a distance sensor. The distance sensor includes a charge generating surface and first and second charge accumulating surfaces. Charges generated in the charge generating area are transferred to the first charge accumulating area during a first period so as to be accumulated in the first charge accumulating area and the second charge accumulating area during a second period so as to be accumulated in the second charge accumulating area. A distance to an object (OJ) is arithmetized based on an amount of charges (Q 1) accumulated in the first charge accumulating area and an amount of charges (Q 2) accumulated in the second charge accumulating area. When pulse light (Lp) is emitted from the light source (LS), the pulse light (Lp) whose light intensity stable period is set in advance within the emission period of the pulse light (Lp) becomes longer than each of the first and second periods, which is from Light source (LS) are emitted.
    公开号:CH711639B1
    申请号:CH00142/17
    申请日:2015-08-04
    公开日:2018-05-15
    发明作者:Mase C/O Hamamatsu Photonics K K Mitsuhito；Hiramitsu C/O Hamamatsu Photonics K K Jun；Shimada C/O Hamamatsu Photonics K K Akihiro
    申请人:Hamamatsu Photonics Kk；
    IPC主号:
    专利说明:

    description
    Technical Field The present invention relates to a distance measuring method and a distance measuring device.
    Background Known distance measuring devices include TOE time-of-flight type distance sensors (see, for example, Patent Literature 1). A distance measuring device disclosed in Patent Literature 1 includes a distance sensor provided with a light receiving layer, a photo gate electrode for transferring charges, and a floating diffusion layer for receiving the charges. In this distance measuring device, charges generated in the light receiving layer due to incident pulse light are allowed to flow into the floating diffusion layer by giving pulse signals to the photo gate electrode. The flowing charges are accumulated in the floating diffusion layer as signal charges. The charges accumulated in the floating diffusion layer are read out as an output corresponding to an amount of the accumulated charges. A distance to an object is calculated based on the output.
    quote list
    Patent Literature Patent Literature 1: Japanese Unexamined Patent Publication No. 2005-235 893.
    Summary of the invention
    Technical Problem In a distance measuring device such as a device disclosed in the above-mentioned Patent Literature 1, even if a drive signal of a light source has a square wave waveform, a light intensity signal from pulse light emitted from the light source will have a trapezoidal waveform which has a rising period, includes a light intensity stable period and a falling period. During the increasing period, the light intensity gradually increases and reaches a predetermined value. During the light intensity stable period, the light intensity remains at the predetermined value or greater. During the falling period, the light intensity falls below the predetermined value and gradually decreases. The present inventors have studied this intensively and found that such a trapezoidal wave of the light intensity signal of the pulse light can impair the distance measuring accuracy of the distance measuring device.
    [0005] Therefore, there is a need for improvements in distance measurement accuracy in the present technical field.
    Problem Solving A distance measuring method according to an aspect of the present invention is a distance measuring method in which a light source configured to emit pulse light with respect to an object and a distance sensor are used, the distance sensor being a charge generating area in which charges are generated according to the incident reflection light of the pulse light reflected from the object, and includes a charge accumulating area in which the charges generated in the charge generating area are accumulated, the distance measuring method including: applying a drive signal (Sd) to the light source to emit a pulse light; Transferring the charges generated in the charge generating area to a first charge accumulating area (FD1) during a first period (T-ι) with respect to an emission period of the pulse light, so as to charge the charges in the first charge accumulating area (FD1) during the first period ( Τ Ί ) to accumulate; Transferring the charges generated in the charge generating area to a second charge accumulating area (FD2) during a second period (T 2 ), which differs in timing from the first period (Τ Ί ) and has the same width as the first period (T- ι) so as to accumulate the charges in the second charge accumulating area (FD2) during the second period (T2); Calculating a distance d to the object (OJ) based on a first amount of charges Q1 accumulated in the first charge accumulating area (FD1) during the first period (T-ι) and a number in the second charge accumulating area (FD2) during the second period (T2) accumulated second amount of charges Q2; and when the pulse light is emitted from the light source (LS), the pulse light whose light intensity stable period is preset within the emission period of the pulse light to be longer than each of the first and second periods is emitted from the light source.
    A distance measuring device according to an aspect of the present invention is a distance measuring device that includes a light source configured to emit pulse light with respect to an object and a distance sensor configured to be a charge-generating surface in which charges are reflected according to incident reflection light of the pulse light reflected by the object are generated, and a charge accumulating area in which the charge generated in the charge generator
    CH 711 639 B1 accumulated area generated charges are included, wherein the distance measuring device includes: a light source drive element (DRV) for applying a drive signal (Sd) to the light source (LS) to emit a pulse light (L P ); a charge transfer unit configured to transfer the charges generated in the charge generating area with respect to an emission period of the pulse light to a first charge accumulating area (FD1) during a first period (Τ Ί ) so as to charge the charges in the first charge accumulating area ( FD1) to accumulate during the first period (T-ι), and configured, the charges generated in the charge-generating area during a second period (T2) which differs in timing from the first period (T-ι) and the same Width as the first period (Τ Ί ) to transfer to a second charge accumulating area (FD2) so as to accumulate the charges in the second charge accumulating area (FD2) during the second period (T2); a distance calculation element (ART) configured to calculate a distance to the object (OJ) based on a first amount of charges Q1 and an in. accumulated in the first charge accumulating area (FD1) during the first period (Τ Ί ) the second charge accumulating area (FD2) accumulated second amount of charges Q2 during the second period (T2); and a the light source drive member configured to drive the light source (LS) so that the pulse light whose light intensity stable period is preset within the emission period of the pulse light is longer than each of the first and second periods from the light source to emit.
    In such inventions, the pulse light is emitted from the light source and penetrates the reflected light of the pulse light reflected from the object into the distance sensor. The charges are generated in the charge-generating surface of the distance sensor in accordance with the incident reflection light. The charges generated in the charge generating area are transferred to the charge accumulating area during the first and second periods so as to be accumulated in the charge accumulating area. The first and second periods differ in timing and are of similar width. The distance to the object is determined based on each of the amount of charges accumulated during the first and second periods.
    In a case where the light intensity signal of the pulse light emitted from the light source has a trapezoidal waveform including a rising period and a falling period as mentioned above, compared to a case where the light intensity signal has a square wave waveform , the amount of charges generated in the charge generating area decreases in the rising period and increases in the falling period. Accordingly, for example, in a case where the first period overlaps the rising period and the second period overlaps the falling period, the amount of charges accumulated in the charge accumulating area during the first period decreases compared to the case of Square wave, and the amount of charges accumulated in the charge accumulating area during the second period increases compared to the case of the rectangular wave. In this way, the amounts of charges that are used to determine the distance to the object can change due to influences of the rising period and falling period. As a result, the distance measurement accuracy may be affected.
    Here, with respect to the pulse light emitted from the light source, the light intensity stable period within the emission period of the pulse light is set in advance so that it is longer than both the first and the second period. Accordingly, with respect to the amount of charges accumulated in the charge accumulating area in each of the first and second periods, a percentage of the amount of charges accumulated in accordance with the light intensity stable period increases and the percentages of the amounts accumulated in accordance with the rise and fall periods decrease Loads. Therefore, it is possible to reduce the influences of the rise and fall periods with respect to the distance measurement accuracy. As a result, the distance measurement accuracy can be improved.
    When pulse light is emitted from the light source, the pulse light can be emitted after a start time of the first period. In such a case, with respect to the amount of charges accumulated in the charge accumulating area during the second period, the percentage of the amount of charges accumulated according to the light intensity stable period of the pulse light increases more. As a result, the distance measurement accuracy can be improved particularly with regard to a short distance.
    A delay time of the emission timing of the pulse light in relation to the start time of the first period can be set in advance to a time which corresponds to a minimum value of a linearity range of a distance measurement profile, which indicates a correlation between an actual distance and a distance determined by the distance sensor. In such a case, it is possible to measure under a condition that a distance zero is shifted to a distance at the minimum value. Therefore, even with a distance range below the minimum value, the distance measurement accuracy can be improved.
    [0013] The distance sensor may include a plurality of charge accumulating areas and a plurality of transfer electrodes configured to transfer the charges generated in the charge generating area to the plurality of charge accumulating areas. The plurality of charge electrodes can be given transfer signals with different phases. In such a case, each time the pulse light is emitted, the generated charges are accumulated in other charge accumulating areas in such a way that the distance to the object can be determined. Therefore, it is possible to prevent the distance measurement accuracy from deteriorating due to time variation of the distance to the object.
    CH 711 639 B1 The distance sensor may include a transfer electrode configured to transfer the charges generated in the charge generating area to the charge accumulating area, and the transfer electrode may be given a transfer signal having a phase intermittently shifted to a predetermined timing , In such a case, the distance measurement can be carried out by at least one transfer electrode and one charge-accumulating surface. Accordingly, it is possible to reduce the distance sensor.
    Advantageous Effects of Invention According to one embodiment of the present invention, it is possible to provide a distance measuring method and a distance measuring device which are capable of improving the distance measuring accuracy.
    Brief Description of Drawings [0016]
    1 is a configuration diagram of a distance measuring device according to the present embodiment. 2 is a cross-sectional view illustrating a configuration of a distance image sensor.
    3 is a schematic top view of the distance image sensor.
    4 is a view illustrating a configuration of the distance sensor.
    Fig. 5 is a cross-sectional view of the configuration along the line V-V in Fig. 4,
    6 is a view illustrating potential profiles in the vicinity of a second main surface of a semiconductor substrate along the line V-V in FIG. 4.
    7 is a view illustrating an impairment of the distance measurement accuracy in the distance measurement method according to a comparative example.
    8 is a distance measurement profile that illustrates a correlation between an actual distance and a distance that is determined by the distance measurement method according to the comparative example.
    9 is an example of a timing chart of various signals in a distance measurement method according to the present embodiment.
    10 is another example of a timing chart of the various signals in the distance measurement method according to the present embodiment.
    11 is a flowchart illustrating a method of setting a light intensity stable period and a delayed irradiation time.
    12 is an example of the distance measurement profile.
    13 is a view illustrating a configuration of a distance sensor according to a modification.
    14 is a timing chart of various signals in a distance measurement method according to the modification.
    DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that elements with common elements and services are denoted by the same reference numerals and redundant explanations are omitted here.
    1 is a configuration diagram of a distance measuring device according to the embodiment.
    A distance measuring device 10 measures a distance d to an object OJ. The distance measuring device 10 includes a distance image sensor RS, light source LS, display DSP and control unit. The control unit contains a drive element (light source drive element) DRV, control element CONT and arithmetic element (distance arithmetic element) ART. The light source LS emits pulse light Lp with respect to the object OJ. The light source LS includes, for example, a laser irradiation device and LED. The distance image sensor RS is a charge distribution type distance image sensor. The distance image sensor RS is arranged on a wiring board WB.
    The control unit (the drive element DRV, control element CONT and arithmetic element ART) include an arithmetic circuit, such as a central processing unit (CPU), a memory, such as a random access memory (RAM) and read only memory (ROM), a power supply circuit and Hardware such as a readout circuit that contains an A / D converter. This control unit can partially or entirely include an integrated circuit, such as an application-specific integrated circuit (ASIC) or field-programmable gate array (FPGA).
    CH 711 639 B1 The drive element DRV applies a drive signal S D to the light source LS in accordance with a control of the control element CONT and drives the light source LS in such a way that the pulse light Lp is emitted to the object OJ. The control element CONT not only controls the drive element DRV, but also outputs first and second transfer signals Si and S2 to the distance sensor RS. The control element CONT controls the display DSP to display arithmetic results of the arithmetic element ART. The arithmetic element ART reads a lot of charges Q1, Q2 from the distance image sensor RS. The arithmetic element ART arithmetizes the distance d based on the read amounts of charges Q1, Q2 and outputs the arithmetic results to the control element CONT. An arithmetic method for distance d will be described later with reference to FIG. 7. The arithmetic results of the arithmetic element ART are input from the control element CONT to the display. The DSP display shows the arithmetic signals.
    In the distance measuring device 10, the drive signal So is applied to the light source LS in such a way that pulse light Lp is emitted from the light source LS. When the pulse light Lp emitted from the light source LS enters the object OJ, the reflected pulse light Lr is reflected by the object OJ and emitted therefrom. The reflected light Lr, which is emitted by the object OJ, penetrates into the charge-generating area of the distance image sensor RS.
    The distance image sensor RS outputs the amounts of charges Ο Ί , Q 2 , which synchronize with the first and second transfer signals S-ι, S 2 , and are collected per pixel. The output quantities of charges Ο Ί , Q 2 are input to the arithmetic element ART in synchronization with the drive signal S D. The arithmetic element ART arithmetizes the distance d per pixel based on the entered amount of charges Ο Ί , Q 2 and the arithmetic results are entered on the control element CONT. The arithmetic results entered on the CONT control element are transmitted to and displayed on the display DSP.
    2 is a cross-sectional view of a configuration of the distance image sensor.
    [0025] The distance image sensor RS is a front-illuminated distance image sensor. The distance image sensor RS contains a semiconductor substrate 1 and a light interception layer LI. The semiconductor substrate 1 includes first and second main surfaces 1 a, 1 b opposite one another. The second main surface 1 b is a light incidence surface. The distance image sensor RS is bonded to the wiring board WB by an adhesive surface FL, the side opposite the first main surface 1a of the semiconductor substrate 1 to the wiring board WB. The adhesive surface FL contains an insulating adhesive and a filler. The light interception layer LI is arranged in front of the second main surface 1 b of the semiconductor substrate 1. The reflected light LR penetrates from the second main surface 1b of the semiconductor substrate 1 into the distance image sensor RS.
    Fig. 3 is a schematic top view of the distance image sensor. It should be noted that the light interception layer LI is omitted in FIG. 3.
    The semiconductor substrate 1 of the distance image sensor RS includes an image recording area 1A, which contains a plurality of distance sensors P (m, n), which are arranged in a two-dimensional manner. Each of the distance sensors P (m, n) outputs the two sizes of charges Ο Ί , Q 2 mentioned above. Correspondingly, the reflection light LR reflected by the object OJ is shaped in the image recording area 1A and a distance image of the object OJ is determined. A distance sensor P (m, n) functions as a pixel. It should be noted that two or more distance sensors P (m, n) can act as one pixel.
    Fig. 4 is a view illustrating a configuration of the distance sensor. FIG. 5 is a cross sectional view of the configuration along the line V-V in FIG. 4. It should be noted that the light intercepting layer LI in FIG. 4 is omitted.
    As mentioned above, the distance image sensor RS includes the light interception layer LI in front of the second main surface 1 b, which is the light incidence surface. An aperture Lia is formed in an area corresponding to each of the distance sensors P (m, n) of the light interception layer LI. The bezel Lia is rectangular in shape. Here, the aperture Lia is formed in a rectangle. The light passes through the diaphragm Lia of the light interception layer LI and penetrates into the semiconductor substrate 1. Accordingly, the diaphragm Lia defines a light receiving surface in the semiconductor substrate 1. The light interception layer LI contains a metal, such as aluminum and the like.
    The semiconductor substrate 1 includes a first semiconductor surface 3 of p-type and a second semiconductor surface 5 of p-type with a lower impurity concentration than the first semiconductor surface 3. The first semiconductor surface 3 is arranged on the side of the first main surface la. The second semiconductor surface 5 is arranged on the second main surface 1b. The semiconductor substrate 1 can be obtained, for example, by growing on a p-type semiconductor substrate, a p »-type epitaxial layer with a lower impurity concentration than that of the semiconductor substrate. An insulating layer 7 is formed on the second main surface 1b (second semiconductor surface 5) of the semiconductor substrate 1.
    [0031] Each of the distance sensors p (m, n) is a charge distribution type distance sensor. Each of the distance sensors p (m, n) includes a photo gate electrode PG, first and second charge accumulating areas FD1, FD2 and first and second transfer electrodes TX1, TX2. The photo gate electrode PG is arranged in accordance with the diaphragm Lia. An area corresponding to the photo gate electrode PG in the semiconductor substrate 1 (second semiconductor area 5) (an area located under photo gate electrode PG in FIG. 5) acts as a charge-generating area in which charges according to FIG
    CH 711 639 B1 the incident reflection light LR of the pulse light Lp, which is reflected by the object OJ, are generated. The photo gate electrode PG corresponds to the shape of the aperture Lia and is rectangular when viewed from above. Here the photo gate electrode PG is shaped in a rectangle similar to the aperture Lia.
    The first and second charge accumulating surfaces FD1, FD2 are arranged to sandwich the photo gate electrode PG. The first and second charge accumulating areas FD1, FD2 are arranged separately from the photo gate electrode PG. Each of the first and second charge accumulating surfaces FD1, FD2 is rectangular in shape when viewed from above. In the present embodiment, each of the first and second charge accumulating areas FD1, FD2 is of a square shape when viewed from above, and they are similar in shape to each other. The first and second charge accumulating areas FD1, FD2 are n-type semiconductor areas with high impurity concentrations, which are formed in the second semiconductor area 5. The first and second charge accumulating areas FD1, FD2 accumulate charges generated in the charge generating area as signal charges.
    The first transfer electrode TX1 is arranged on the insulating layer 7 and between the first charge accumulating surface FD1 and the photo gate electrode PG. The first transfer electrode TX1 is arranged separately from both the first charge accumulating surface FD1 and the photo gate electrode PG. The first transfer electrode TX1 transfers the charges generated in the charge generating area to the first charge accumulating area FD1 during a first period Τ Ί (see FIG. 7) in accordance with the first transfer signal Si (see FIG. 7). The first period Τ Ί corresponds to an emission period T T of the pulse light Lp (see FIG. 7).
    The second transfer electrode TX2 is arranged on the insulating layer 7 and between the second charge accumulating surface FD2 and the photo gate electrode PG. The second transfer electrode TX2 is arranged separately from both the second charge accumulating surface FD2 and the photo gate electrode PG. The second transfer electrode TX2 transfers the charges generated in the charge generating area to the second charge accumulating area FD2 during a second period T2 (see FIG. 7) in accordance with the second transfer signal S 2 (see FIG. 7 with a phase other than that of the first transfer signal S-ι The second period T 2 differs from the first period Τ Ί in timing and is similar in width to the first period Τ Ί .
    As mentioned above, the control element CONT outputs the first and second transfer signals Si, S 2 . The first and second transfer signals S-ι, S 2 , which are output by the control element CONT, are applied to the first and second transfer electrodes TX1, TX2. Accordingly, the first and second transfer electrodes TX1, TX2 distribute the charges generated in the charge generating area and transfer the charges to the first and second charge accumulating areas FD1, FD2. Therefore, part of the control element CONT and the first and second transfer electrodes TX1, TX2 function as a charge transfer unit.
    Each of the first and second transfer electrodes TX1, TX2 is rectangular in shape when viewed from above. Here, each of the first and second transfer electrodes TX1, TX2 is formed in a rectangle and they are similar in shape. Long side lengths of the first and second transfer electrodes TX1, TX2 are shorter than long side lengths of the photo gate electrode PG.
    The insulating layer 7 is provided with contact holes for exposing the surface of the second semiconductor area 5. Conductors 13 for connecting the first and second charge accumulating surfaces FD1, FD2 to the outside thereof are arranged in the contact holes.
    Here, the expression “foreign substance concentrate is high” represents that the foreign substance concentration is, for example, equal to or greater than 1 χ 10 17 cm -3 , and is indicated by “+” attached to the conductivity type. On the other hand, an expression "foreign matter concentration is low" represents that the foreign matter concentration is, for example, equal to or less than 10 χ 10 15 cm -3 , and is indicated by "-" attached to the conductivity type.
    [0039] A thickness / impurity concentration of each semiconductor area is as follows. First semiconductor area 3: thickness 10 to 1000 pm / foreign substance concentration 10 χ 10 12 to 10 19 cm -3 ; second semiconductor area 5: thickness 1 to 50 pm / foreign substance concentration 1 χ 10 12 to 10 15 cm -3 ; first and second charge accumulating areas FD1, FD2: thickness 0.1 to 1 pm / impurity concentration 1 χ 10 18 to 10 20 cm -3 .
    The semiconductor substrate 1 (first and second semiconductor areas 3, 5) is given a reference potential, such as a ground potential, by a back gate or a through electrode or the like. The semiconductor substrate 1 contains Si, the insulating layer 7 contains SiO 2 and the photo gate electrode PG and the first and second transfer electrodes TX1, TX2 contain poly-silicon. It should be noted that other materials can be included in these elements.
    There is a 180 degree shift between the phase of the first transfer signal Si, which is applied to the first transfer electrode TX1, and the phase of the second transfer signal S 2 , which is applied to the second transfer electrode TX2. The light incident on each of the distance sensors P (m, n) is converted into charges in the semiconductor substrate 1 (second semiconductor area 5). Some of the charges generated in this way are allowed to migrate as the signal charges to the first transfer electrode TX1 or second transfer electrode TX2 using potential gradients. The potential gradient is formed by voltage which is applied to the photo gate electrode PG and the first and second transfer electrodes TX1, TX2.
    CH 711 639 B1 When a positive potential is applied to the first transfer electrode TX1 or the second transfer electrode TX2, a potential of an area of the semiconductor substrate 1 (second semiconductor area 5) below the first transfer electrode TX1 or the second transfer electrode TX2 becomes lower with respect to electrons as a potential of an area of the semiconductor substrate 1 (second semiconductor area 5) under the photo gate electrode PG. Accordingly, negative charges (electrons) are drawn in the direction of the first transfer electrode TX1 or the second transfer electrode TX2, and the negative charges are accumulated in potential wells which are formed by the first and second charge-accumulating areas FD1, FD2. Each of the n-type semiconductors contains a positively ionized donor and has the positive potential and attracts the electrons. When a potential lower than the positive potential (for example, the ground potential) is applied to the first transfer electrode TX1 or the second transfer electrode TX2, a potential barrier is caused by the first transfer electrode TX1 or the second transfer electrode TX2. Therefore, the charges generated in the semiconductor substrate 1 are not drawn into the first and second charge accumulating areas FD1, FD2.
    FIG. 6 is a view illustrating potential profiles in the vicinity of the second main surface of the semiconductor substrate along the line V-V in FIG. 4.
    In Fig. 6, downward directions represent positive directions of potentials. FIG. 6 shows a potential φτχι of an area exactly below the transfer electrode TX1, a potential φ Τ einer2 of an area exactly below the second transfer electrode TX2, a potential <p PG of the charge-generating area just below the photo gate electrode PG, a potential φ Ρ0Ί of the first charge accumulating area FD1 and a potential φ Ρ02 of the second charge accumulating area FD2.
    If the potentials (φτχ-ι, φτχ2) of the areas under the adjacent first and second transfer electrodes TX1, TX2 are defined as reference potentials without bias, the potential <p PG of the area (charge-generating area) becomes exactly under the photo gate -Electrode PG set higher than the reference potentials. The potential <p PG of the charge-generating area is higher than the potentials φτχ-ι, <Ρτχ2 · Therefore, the potential profile is formed like a recess that points downwards in the drawings in the charge-generating area.
    Accumulating operation of the charges will be described with reference to FIG. 6. When the phase of the first transfer signal S-ι applied to the transfer electrode TX1 is zero degrees, the first transfer electrode TX1 is given the positive potential. The second transfer electrode TX2 is given a potential in the opposite phase, namely a potential in a phase of 180 degrees (for example the ground potential). The photo gate electrode PG is given a potential between the potential given to the first transfer electrode TX1 and the potential given to the second transfer electrode TX2. In such a case, as illustrated in FIG. 6a, the potential φτχ of the semiconductor under the first transfer electrode TX1 falls below the potential <p PG of the charge-generating area. Therefore, the charges e generated in the charge generating area are allowed to flow into the potential well of the first charge accumulating area FD1.
    On the other hand, the potential φτχ2 of the semiconductor will not drop under the second transfer electrode TX2. Therefore, the charges do not flow into the potential well of the second charge accumulating area FD2. Accordingly, the charges in the potential well of the first charge accumulating surface FD1 are collected and accumulated. Since the first and second charge accumulating areas FD1 and FD2 are doped with foreign substances of the n-type, their potentials are reset in the positive direction.
    When the phase of the second transfer signal S 2 applied to the second transfer electrode TX2 is zero degrees, the second transfer electrode TX2 is given the positive potential. The first transfer electrode TX1 is given a potential in the opposite phase, that is, a potential in a phase of 180 degrees (for example, a ground potential). The photo gate electrode PG is given a potential between the potential given to the first transfer electrode TX1 and the potential given to the second transfer electrode TX2. In such a case, as illustrated in FIG. 6b, the potential φτχ2 of the semiconductor falls just below the second transfer electrode TX2 below the potential <p PG of the charge-generating area. Therefore, the negative charges e generated in the charge generating area are allowed to flow into the potential well of the second charge accumulating area FD2.
    On the other hand, the potential φτχ-ι of the semiconductor does not fall below the first transfer electrode TX1. Therefore, the charges will not fall into the potential well of the first charge accumulating area FD1. Accordingly, the charges in the potential well of the second charge accumulating area FD2 are collected and accumulated.
    In this way, the charges in the potential wells of the first and second charge accumulating areas FD1 and FD2 are collected and accumulated. The charges accumulated in the potential wells of the first and second charge-accumulating areas FD1, FD1 are read on the outside thereof.
    Fig. 7 is a view illustrating the deviation of the distance measuring accuracy in a distance measuring method according to a comparative example. Specifically, Fig. 7a is a timing chart of various signals in a case where a light intensity signal of pulse light at an time when the pulse light is emitted from the light source has an ideal square wave waveform. Figure 7b is a timing diagram of the various signals in an actual case. 7c is a view comparing a light intensity signal of reflected light when the light returns to an image pickup surface.
    CH 711 639 B1 First, a case will be described with reference to Fig. 7a in which a light intensity signal S Lp of pulse light Lp at a time when the pulse light Lp is emitted from the light source LS has the ideal square wave waveform. 7a illustrates a drive signal S D , which is applied to the light source LS, by the control element CONT, the light intensity signal Sl p of the pulse light Lp when the pulse light Lp is emitted from the light source LS, an intensity signal Si_ r of reflected light Lr if the reflected light Lr returns to an image pickup surface 1A, a first transfer signal Si to be applied to the first transfer electrode TX1 and a second transfer signal S 2 to be applied to the second transfer electrode TX2.
    As described in Fig. 7a, the drive signal S D , the light intensity signal S Lp , S Lr and first and second transfer signals Si, S 2 are all pulse signals which have the ideal square wave waveform. These signals are all set to be in a low state before the drive signal So is applied to the light source LS.
    The drive signal S D is a pulse signal of a pulse width Tp. The pulse width Tp of the drive signal S D is equivalent to a set value of a pulse width of the light intensity signal Sl p . In such a case, since the light intensity signal S Lp has the ideal square wave waveform, the pulse width of the light intensity signal Sl p becomes equivalent to the pulse width Tp of the drive signal So according to the setting. The drive signal So is set to a low level after being set to a high level during the pulse width Tp. The light intensity signal S Lp rises simultaneously with a start time for applying the drive signal S D , and the light intensity signal S Lp is set to a level corresponding to the light intensity of the pulse light Lp. The light intensity signal S Lp falls after the pulse width Tp and is set to a low level.
    Synchronizing with the emission of the pulse light Lp, the first and second transfer signals S-ι, S 2 are applied to the first and second transfer electrodes TX1, TX2 in antiphase. Specifically, the first transfer signal S-ι synchronizes with the light intensity signal S Lp by a phase difference of zero degrees and is applied to the first transfer electrode TX1 during the pulse width Tp so as to be set at a high level. The second transfer signal S 2 synchronizes with the light intensity signal Sl p by a phase difference of 180 degrees and is applied to the second transfer electrode TX2 during the pulse width Tp so as to be set at a high level. Periods when the first and second transfer signals S-ι, S 2 are set to a high level are first and second periods Tu T 2 . The first and second periods Tu T 2 differ in timing and are similar in width. In such a case, each width of the first and second periods Tu T 2 is equivalent to the pulse width Tp of the drive signal S D.
    The light intensity signal Su · rises simultaneously with the time when the reflection light Lr returns to the image pickup surface 1A, and the light intensity signal SLr is set to a level corresponding to the light intensity of the reflection light S Lr . The light intensity signal S Lr falls after the pulse width Tp and is set to the low level. In such a case, the pulse width of the light intensity signal S Lr is equivalent to the pulse width Tp of the drive signal S D. A phase difference Td between the light intensity signal S Lp and the light intensity signal S Lr is a time of flight (TOF) of light. The phase difference Td corresponds to the distance d from the distance image sensor RS to the object OJ.
    The charges generated in the charge generating area in accordance with the incident reflection light Lr are transferred to the first charge accumulating area FD1 during the first period Ti when the first transfer signal S-ι is high with respect to an emission period T T of the pulse light Lp is set so as to be accumulated in the first charge accumulating area FD1 during the first period Τ Ί . The emission period T T of the pulse light Lp is a period when the light intensity signal Sl p is not at the low level. In such a case, the width of the emission period T T is equivalent to the pulse width Tp of the drive signal So. The charges generated in the charge generating area in accordance with the incident reflection light Lr are transferred to the second charge accumulating area FD2 during the second period T 2 , when the second transfer signal S 2 is set to the high level so as to be accumulated in the second charge accumulating area FD2 during the second period T 2 .
    The charges are generated in the charge accumulating area during a period when the reflected light Lr enters the area. Therefore, an amount of charges Q-ι accumulated in the first charge accumulating area FD1 will be an amount of charges to be accumulated during one period within the first period Tu when the light intensity signal SLr and the first transfer signal S-ι overlap. Furthermore, an amount of charges Q 2 accumulated in the second charge accumulating area FD2 will be an amount of charges to be accumulated during one period within the second period T 2 when the light intensity signal S Lr and the second transfer signal S 2 overlap.
    The distance d is calculated by the following formula (1) based on a rate (distribution rate) of the amount of charges Q-ι and amount of charges Q 2 . It should be noted that c represents the speed of light.
    Distance d = (c / 2) χ (Tp χ Q 2 / (Qi + Q 2 )) .... (1) A measurable distance range d in such a case depends on the width of each of the first and second periods Tu T 2 and the measurable distance is a distance in which the phase difference Td is set within the width of each of the first and second periods Tu T 2 . In other words, the distance d becomes when the phase difference Td
    CH 711 639 B1 becomes equivalent to the width of each of the first and second periods Τ Ί , T 2 , a maximum value of the measurable distance d. Therefore, a distance measurement range that is a width of a distance range to be measured can be set based on the width of each of the first and second periods Τ Ί , T 2 . It should be noted that “measurable” indicates that the distance d can theoretically be calculated using the formula (1) mentioned above.
    Referring to Figs. 7b and 7c, the actual case is described below. As illustrated in FIG. 7b, the light intensity signal Sl p , Si_r have trapezoidal waveforms. Each of the light intensity signals Sl p , So gradually increases and reaches a predetermined value during a rising period T R and remains at the predetermined value or larger during a light intensity stable period T s and then falls below the predetermined value and gradually decreases during a falling period T F. In such a case, the emission period T T of the pulse light Lp becomes longer than the pulse width Tp of the drive signal S D. It should be noted that the light intensity stable period T s does not only indicate a period when the light intensity signals S Lp , S Lr are constant but also indicates a period when the light intensity signals S Lp , S Lr are held, for example at or within 5% of the maximum value. In a case where the period when the light intensity signals S Lp , S Lr become constant is referred to as the light intensity stable period T s , is a period in which the rising period T R and falling period T F from the emission period T T of the pulse light Lp are subtracted, the light intensity stable period T s . In such a case, the emission period T T of the pulse light Lp is equivalent to a sum of the width of the falling period T F and the pulse width Tp of the drive signal So. As illustrated in FIG. 7c, in the actual case, compared to a case, in which the light intensity signals Sl p , SLr have the ideal square wave waveforms, the amount of charges Q-ι by an amount of charges qi due to an influence of the increasing period T R. Furthermore, the amount of charges Q 2 increases by an amount of charges q 2 due to an influence of the falling period T F. In this way, the distance measurement accuracy is impaired in the distance measurement method according to the comparative example, since the charge distribution ratio differs from the ideal case.
    8 is a distance measurement profile that illustrates a correlation between an actual distance and a distance that is determined by the distance measurement method according to the comparative example.
    8, an actual distance d is taken along the abscissa and a distance (a calculated distance) d ca i along the ordinate determined by the distance measuring method according to the comparative example is taken. The pulse light Lp, whose pulse width Tp of the drive signal So is 30 ns, is determined and used for the measurement. Distances in the abscissa and ordinate are distance-measurable areas, if the width is set to 30 ns as in the first and second periods Τ Ί , T 2 , similar to the pulse width Tp of the drive signal So- A linear line B is a straight line that the Origin of the coordinates passes and has an inclination of 1.
    As illustrated in FIG. 8, the distance measurement profile is in a linearity area A | a and non-linearity areas A shO rt, Aiong divided. The linearity area A | ine is an area where the actual distance d and calculated distance d ca i are essentially similar (equivalent) and where there is a difference between the calculated distance d ca i and the actual distance d (Id-d ca il / dx 100 ( %)) is at or below a tolerance limit. The linearity area A | For example, ine is an area where the difference is several% or less. In the linearity area A | ine is the difference so small that the distance measuring accuracy is high. In the linearity area A | ine are plotted measured data substantially at the linear line B.
    On the other hand, the non-linearity areas A shO rt, Aiong are different areas than the linearity area A | ine . Those surfaces include a surface where the actual distance d and calculated distance d ca i are not equivalent in one surface, at least at the linearity surface A | ine adjacent. In other words, the non-linearity areas A short , A | Ong contain an area where the actual distance d and calculated distance d ca i are equivalent in an area that is not adjacent to the linearity area A | ine is. The area where the actual distance d and the calculated distance d ca i are not equivalent indicates an area where the difference exceeds the tolerance limit, for example the difference exceeds several%. The non-linearity area A shO rt becomes a closer distance to the short distance than the linearity area A | ine plotted. The non-linearity area A | Ong is plotted in a closer position to a long distance than the linearity area A | ine .
    In the non-linearity areas A short , Aiong, the measured data are plotted in positions offset with respect to the linear line B. In the non-linearity areas A shO rt, Aiong, the difference is so large that the distance measurement accuracy is low. This is because the influence of the amount of charges q 2 with respect to the amount of charges Q 2 in the non-linearity area A short becomes large. Furthermore, it is because the influence of the amount of charges q-ι in relation to the amount of charges Ο Ί in the non-linearity area A | Ong grows.
    Fig. 9 is an example of a timing chart of various signals in a distance measuring method according to the present embodiment.
    As illustrated in Fig. 9, in the example of the distance measuring method according to the present embodiment, the pulse width Tp of the drive signal S D is set in advance to be an extension time Tx longer than the width of each of the first and second periods Τ Ί , T 2 . Accordingly, the width of the light intensity stable period T s of the pulse light Lp emitted from the light source L s is set in advance to be longer than the width of each of the first and second periods Τ Ί , T 2 . Similar to the comparative example, it should be noted that the first and second periods T-ι, T 2 are different in timing and of similar width.
    CH 711 639 B1 In such a case, with respect to the amounts of charges of Ο Ί , Q 2 accumulated in the first and second charge accumulating areas FD1, FD2, a percentage increases in accordance with the light intensity stable period T s of the pulse light Lp accumulated charges. Therefore, with respect to the amount of charges q 3 , which decreases compared to the ideal case due to the rise period T R , the influence of such an amount of charges q-ι with respect to the amount of charges Q-ι becomes small. Furthermore, with respect to the amount of charges q 2 that increases from the ideal case due to the falling period T F , the influence of such an amount of charges q 2 with respect to the amount of charges Q 2 becomes small. As a result, the influences of the rising period T R and falling period T F of the light intensity signal S Lp are reduced with respect to the distance measurement accuracy. The distance measurement accuracy can be improved accordingly.
    Fig. 10 is another example of the timing chart of the various signals in the distance measuring method according to the present embodiment.
    As illustrated in Fig. 10, in another example of the distance measuring method according to the present embodiment, the pulse width Tp of the drive signal So is set in advance to be longer than the width of each of the first and second periods Τ Ί , T 2 to be the extension time Tx , In addition, the drive signal So is set in advance to be applied later than the first transfer signal Si by a delayed broadcasting time (delay time) Ty.
    In such a case, with respect to the amount of charges Q 2 accumulated in the second charge accumulation area FD2, the percentage of the charges accumulated in accordance with the light intensity stable period T F of the pulse light Lp continues to increase. Accordingly, with regard to the amount of charges q 2 , which ideally increases due to the falling period T F , the influence of such an amount of charges q 2 with respect to the amount of charges Q 2 continues to be small. This reduces the influence of the falling period T F of the light intensity signal S Lp with regard to the distance measurement accuracy, in particular with regard to the short distance. As a result, the distance measurement accuracy can be improved particularly with respect to the short distance. When calculating the distance d, it should be noted that a distance corresponding to the delayed broadcast time Ty is necessarily offset.
    Referring to Fig. 11, a method of setting, in advance, the light intensity stable period T s and the delayed broadcasting time Ty will be described. 11 is a flowchart illustrating a process of setting the light intensity stable period and delayed emission time. 12 is an example of the distance measurement profile.
    As illustrated in FIG. 11, various measurement conditions are initially set as the initial setting, similar to the distance measurement method according to the comparative example (step S01). Specifically, the width of each of the first and second periods T-ι, T 2 is set to a value TO corresponding to the distance range to be measured, and the distance measuring range is set. The pulse width Tp of the drive signal S D is similarly set to TO. The delayed broadcast time Ty is set to zero. In accordance with the delayed transmission time Ty, an offset d O f S of the delayed transmission time Ty is set to zero with respect to the calculated distance d ca i.
    Next, the distance measurement profile indicating the relationship between the calculated distance d ca i and the actual distance d is prepared (step S02). As illustrated in FIG. 12, the distance measurement profile is divided into the linearity area Anne and the non-linearity areas A shO rt, A | Ong divided.
    Next, a distance distance d | of the linearity area A | ine and a minimum value dshort of the distance range d | tested ine and a time range T | ine and a minimum value T shor t thereof corresponding to the above-mentioned distance range d | ine and the minimum value d shO rt calculated (step S03). Here the minimum value dshort corresponds to the linearity area A | ine a value of the distance range of the non-linearity area A Sho rt · [0081] Next, the measurement conditions are set again (step S04). Specifically, the pulse width Tp of the drive signal S D is set to TO + (TO-T | ine ). The delayed broadcast time Ty is set to T shor t. In accordance with the delayed transmission time Ty, the offset d O f S of the delayed transmission time Ty is set to d short in relation to the calculated distance d ca i. The width of each of the first and second periods T ^ T 2 is not changed.
    Next, the distance measurement profile is prepared again (step S05). It is next determined whether desired linearity properties are determined in the distance measurement profile (step S06). Specifically, the distance range diine of the linearity area A | ine and the minimum value d short of the linearity area A | ine determine whether they lie within desired ranges. The wider the distance range d | ine , the wider the distance range that can be measured with high accuracy becomes. Furthermore, the smaller the minimum value dshort, the shorter the minimum distance that can be measured with high accuracy.
    In a case where the answer in step S06 is yes, the process is completed. The minimum value T shor t of the time range T | ine set as delayed broadcasting time Ty. Furthermore, the time range Tiine corresponds to the linearity area A | ine set as the light intensity stable period T s . It should be noted that the pulse width Tp of the transfer electrodes is of course set in advance when the light intensity stable period T s is set in advance. In a case where the answer in step S06 is no, the process moves to step S03 and the processes from steps S03 to S06 are repeated.
    CH 711 639 B1 In the present embodiment, the influences of the rising period T R and falling period T F may not completely disappear and the entire distance measuring range may not be considered as the linearity area A | ine can be set with high distance measurement accuracy. However, by setting the light intensity stable period T s in advance long, the percentages of the rising period T R and falling period T F within the emission period T T of the pulse light Lp are relatively reduced. Therefore, it is possible to reduce the influences of the rising period T R and falling period T F. A percentage of the linearity area A | increases accordingly ine with high distance measuring accuracy in the entire distance measuring range. As a result, the distance measurement accuracy is improved.
    As mentioned above, in the distance measuring method according to the present embodiment, when the pulse light Lp is emitted from the light source L s , the pulse light Lp is emitted whose light intensity stable period T s within the emission period T T of the pulse light Lp from the light source L s is preset to be longer than each of the first and second periods Τ Ί , T 2 .
    The distance measuring device 10 according to the present embodiment includes the drive element DRV configured to drive the light source L s , the pulse light Lp, whose light intensity stable period T s is preset to be longer within the emission period T T of the pulse light Lp, to emit as each of the first and second periods T-ι, T 2 .
    Accordingly, with respect to the amounts of charges Ο Ί , Q 2 accumulated in the first and second charge accumulating areas FD1, FD2 during each of the first and second periods Τ Ί , T 2 , the percentage of the amount increases in accordance with FIG light intensity stable period T s accumulated charges and the percentages of the amounts of charges accumulated in accordance with the increasing period T R and falling period T F decrease. Therefore, with regard to the amount of charges Ο Ί , which decreases from the ideal case due to the rise period T R , the influence of such an amount of charges q-ι with respect to the amount of charges Qi becomes small. Furthermore, with respect to the amount of charges q 2 , which increase compared to the ideal case due to the falling period T F , the influence of such an amount of charges q 2 with respect to the amount of charges Q 2 becomes small. As a result, the influences of the rising period T R and falling period T F of the light intensity signal Sl p are reduced with respect to the distance measurement accuracy. The distance measurement accuracy can be improved accordingly.
    In the distance measuring method based on the above-mentioned formula (1), the pulse widths Tp of the drive signal S D become as long as the width of each of the first and second periods T-ι, T 2 are set. It is thus possible to measure from the distance where the phase difference Td is zero to the distance where the phase difference Td measures the width of each of the first and second periods Τ Ί , T 2 . However, even though the pulse width Tp of the drive signal So is set as long as the width of each of the first and second pulse periods Τ Ί , T 2 , the width of the light intensity stable period T s actually decreases due to the influences of the rising period T R and falling period T F. On the other hand, if the pulse width T P of the drive signal S D is intentionally set to be long in advance such that the width of the light intensity stable period T s is intentionally set to be long in advance, it is possible to compensate for the influence caused by the decrease in the width the light intensity stable period T s is caused.
    Further, when the pulse light Lp is emitted from the light source LS, the pulse light Lp is emitted later than the start time of the first period Ti by the delayed radiation time Ty. Accordingly, the amount of accumulated charges Q 2 to increase in terms of the second surface ladungsakkumulierenden FD2 during the second period T 2, the percentage of the amount of light intensity in accordance with the stable period T s accumulated charges on. As a result, the distance measurement accuracy can be improved, particularly with respect to the short distance.
    Furthermore, the delayed radiation time Ty of the emission timing of the pulse light Lp with respect to the start time of the first period Ti is beforehand the minimum value T short corresponding to the minimum value d shO rt of the linearity area A | ine of the distance measurement profile, which indicates the correlation between the distance d ca i determined by the actual distance d and the distance sensor P (m, n). In such a case, it is possible to measure under a condition in which the distance zero is offset from the minimum value d S hort. Therefore, it is possible to improve the distance measurement accuracy even with respect to the distance range below the minimum value d shO rt.
    Furthermore, the distance sensors P (m, n) include the first and second charge accumulating areas FD1, FD2 and the first and second transfer electrodes TX1, TX2, which are configured, the charges generated in the charge generating area to the first and second charge accumulating areas FD1, FD2 to transfer. The first and second transfer electrodes TX1, TX2 are given the first and second transfer signals S-ι, S 2 . There is a 180 degree shift between the phases of the first and second transfer signals S-ι, S 2 . Accordingly, each time the pulse light Lp is emitted once, the generated charges are accumulated in each of the first and second charge accumulating areas FD1, FD2, and the distance d to the object OJ can be determined. Therefore, it is possible to prevent the distance measurement accuracy from being impaired due to the time variation of the distance d to the object OJ.
    A modification of the present embodiment will be described below. 13 is a view illustrating a configuration of a distance sensor according to the modification. It should be noted that a light interception layer LI is omitted in FIG. 13.
    CH 711 639 B1 As illustrated in FIG. 13, a distance sensor P (m, n) according to the modification includes a photo gate electrode PG, first charge accumulating surface FD1, and first transfer electrode TX1. The distance sensor P (m, n) according to the modification differs from the above-mentioned embodiment in that it does not contain the second charge accumulating surface FD2 and the second transfer electrode TX2.
    The photo gate electrode PG is of a rectangular ring shape under supervision. In the present modification, the photo gate electrode PG is a square ring shape under supervision. A periphery of the photo gate electrode PG corresponds to a periphery of the distance sensor P (m, n). The first charge accumulating surface FD1 is formed within the square ring of the photo gate electrode PG. The first charge accumulating surface FD1 is rectangular in shape when viewed from above. In the present embodiment, the first charge accumulating area FD1 is of a square shape. The first charge accumulating surface FD1 when viewed from above is arranged in a substantial center of the distance sensor P (m, n).
    The first transfer electrode TX1 is arranged between the photo gate electrode PG and the first charge accumulating surface FD1. The first transfer electrode TX1 has a rectangular ring shape when viewed from above. In the present modification, the first charge accumulating surface FD1 is a square ring shape when viewed from above. Fig. 14 is a timing chart of various signals in a range method according to the modification.
    As illustrated in FIG. 14, the first transfer signal S-ι, which is applied to the first transfer electrode TX1, is given a phase shifted intermittently to a predetermined timing. In the present modification, the first transfer signal Si is given a phase shifted by 180 degrees at a time of 180 degrees. The first transfer signal S-ι synchronizes with a drive signal S D at a time of zero degrees and has a phase difference of 180 degrees compared to the drive signal S D at a time of 180 degrees.
    In the present modification, an amount of charges Q-ι accumulated in the first charge accumulating area FD1 at the time of 0 degrees and an amount of charges Q 2 accumulated in the first charge accumulating area FD1 at a time of 180 degrees are alternately read out. A distance d is calculated based on these amounts of charge Q ,, Q. 2
    In such a manner, the distance sensor P (m, n.) Includes the first transfer electrode TX1, which is configured to transfer the charges generated in the charge generating area to the first charge accumulating area FD1. The first transfer electrode TX1 is given the first transfer signal S-ι with the phase shifted intermittently by 180 degrees at the time of 180 degrees. In such a case, the distance measurement can be carried out at least by a transfer electrode TX1 and a first charge accumulating surface FD1. Therefore, the distance sensor P (m, n) can be reduced.
    The present invention should not be limited to the aforementioned embodiment. For example, in the above-mentioned embodiment, the extension time Tx and the delayed broadcasting time Ty are set while preparing the distance measurement profile, but the embodiment should not be limited to this. If there is known information regarding a signal waveform of the light intensity signal Sl p of the pulse light Lp when the pulse light Lp is emitted from the light source Ls, the extension time Tx and delayed emission time Ty can be set based on the information. For example, if the width of the light intensity stable period T s is known, a difference between the width of each of the first and second periods T-ι, T 2 and the width of the light intensity stable period T s can be set as the extension time Tx.
    Furthermore, if the width of the rise period T R of the light intensity signal Sl p is known, a value that subtracts the width of the rise period T R from the pulse width Tp of the drive signal So can be considered as the width of the light intensity stable period T s . Similarly, the expansion time Tx can be set based on the considered width of the light intensity stable period T s .
    Furthermore, when the pulse light Lp is emitted from the light source LS, the pulse light Lp can be emitted before the start time of the first period T-ι. In such a case, the delayed broadcasting time Ty is negative. In a range close to the maximum value of the distance range, which can be measured by the above-mentioned formula (1), that is, e.g. B. the non-linearity area A | Ong , the influence of the rise period T R of the light intensity signal S Lp is large. In other words, the influence of the amount of charges q-ι in relation to the amount of charges Q-ι that decreases from the ideal is large in this area. By setting the delayed radiation time Ty to a negative value, the influence of the amount of charges q-ι in relation to the amount of charges Q-ι is small, which improves the distance measurement accuracy in this area.
    In the distance image sensor RS, each of the distance sensors P (m, n) is arranged two-dimensionally, but each of them can be a line sensor which is arranged one-dimensionally. It should be noted that a two-dimensional image can also be obtained by rotating a line sensor or scanning with two line sensors.
    The distance image sensor RS is not limited to the front-illuminated distance image sensor. The distance image sensor RS can be a backlit distance image sensor.
    The charge generating area where the charges are generated in accordance with the incident light may include a photodiode (e.g. an embedded photodiode).
    CH 711 639 B1
    The conductivity types (i.e., p-type and n-type of the distance image sensor RS according to the present embodiment can be replaced with each other to be opposite to those described above.
    Industrial Applicability The present invention is applicable to a distance measuring method and a distance measuring device.
    Reference symbol list [0107]
    Distance measuring device
    Without linearity area d distance dshort Minimum value of linearity area
    FD1 first charge accumulating area
    FD2 second charge accumulating area
    P distance sensor
    PG photo gate electrode first transfer signal
    5 2 second transfer signal
    T-, first period
    T 2 second period
    TX1 first transfer electrode (charge transfer unit)
    TX2 second transfer electrode (charge transfer unit)
    L s light source
    CONT control element (charge transfer unit)
    DRV drive element (light source drive element)
    ART arithmetic element (distance arithmetic element)
    OJ object
    Lp pulse light
    Lr reflection light
    T s light intensity stable period
    T T emission period of pulse light
    Ty delayed broadcast time (delay time)
    Qi, Q 2 amount of charges
    权利要求:
    Claims (6)
    [1]
    claims
    1. Distance measurement method in which a light source (LS) configured to emit pulse light (L P ) with respect to an object (OJ) and a distance sensor (P) are used, the distance sensor (P) being a charge generating surface , in which charges are generated according to the incident reflection light of the pulse light (L P ) reflected by the object, and a charge accumulating area (FD1, FD2) in which the charges generated in the charge generating area are accumulated, the distance measuring method comprising:
    Applying a drive signal (So) to the light source (LS) for emitting a pulse light (L P );
    CH 711 639 B1
    Transferring the charges generated in the charge generating area to a first charge accumulating area (FD1) during a first period (TJ with respect to an emission period of the pulse light, so as to accumulate the charges in the first charge accumulating area (FD1) during the first period (TJ ;
    Transferring the charges generated in the charge generating area to a second charge accumulating area (FD2) during a second period (T 2 ), which differs in timing from the first period (TJ and has the same width as the first period (TJ, and so on accumulate the charges in the second charge accumulating area (FD2) during the second period (T 2 );
    Calculating a distance d to the object (OJ) based on a first amount of charges Ο Ί accumulated in the first charge accumulating area (FD1) during the first period (TJ ) and on the second charge accumulating area (FD2) during the second period (T 2 ) accumulated second amount of charges Q 2 ; and when emitting the pulse light from the light source (LS), emitting the pulse light whose light intensity stable period is preset within the emission period of the pulse light to be longer than each of the first and second periods from the light source.
    [2]
    2. Distance measuring method according to claim 1, wherein the pulse light is emitted after the start time of the first period.
    [3]
    3. Distance measuring method according to claim 2, wherein a delay time (Ty) of the emission timing of the pulse light (Lp) with respect to the start time of the first period (TJ is set in advance to a minimum value (T shO rt) which corresponds to a minimum value (d shO rt) corresponds to a linearity area (A | ine ) of a distance measurement profile, which indicates a correlation between an actual distance and a distance calculated by the distance sensor.
    [4]
    4. The distance measuring method according to claim 1, wherein the distance sensor includes a plurality of charge accumulating areas and a plurality of transfer electrodes configured to transfer the charges generated in the charge generating area to the plurality of charge accumulating areas. and transfer signals having different phases are given to the plurality of transfer electrodes.
    [5]
    5. The distance measuring method according to one of claims 1 to 3, wherein the distance sensor includes a transfer electrode configured to transfer the charges generated in the charge generating area to the charge accumulating area, and the transfer electrode is given a transfer signal that is related to has an emission period of the pulse light intermittently shifted at a predetermined timing.
    [6]
    6. A distance measuring device comprising a light source configured to emit pulse light with respect to an object and a distance sensor configured to have a charge generating area in which charges are generated according to the incident reflection light of the pulse light reflected from the object, and a charge accumulating area , in which the charges generated in the charge generating area are accumulated, the distance measuring device comprising:
    a light source drive element (DRV) for applying a drive signal (So) to the light source (L s ) to emit a pulse light (L P );
    a charge transfer unit configured to transfer the charges generated in the charge generating area with respect to an emission period of the pulse light to a first charge accumulating area (FD1) during a first period (TJ) so as to charge the charges in the first charge accumulating area (FD1) accumulate during the first period (TJ) and is configured to charge the charges generated in the charge generating area during a second period (T 2 ) that differs from the first period (TJ in timing and is the same width as the first period (TJ comprises transferring to a second charge accumulating area (FD2) so as to accumulate the charges in the second charge accumulating area (FD2) during the second period (T 2 );
    a distance calculation element (ART) configured to calculate a distance to the object (OJ) based on a first amount of charges Ο Ί and one accumulated in the first charge accumulating area (FD1) during the first period (TJ) second charge accumulating area (FD2) accumulates second amount of charges Q 2 during the second period (T 2 ); and the light source driving element configured to drive the light source (L s ) so that it can supply the pulse light whose light intensity stable period within the emission period of the pulse light is set to be longer than each of the first and second periods to emit from the light source.
    CH 711 639 B1
    CH 711 639 B1
    FL
    WB
    1a
    CH 711 639 B1
    CH 711 639 B1
    X1 FD1 -
    CH 711 639 B1
    - ~ v ~ ω
    CH 711 639 B1 (b)
    CH 711 639 B1 (b) (C)
    Vtx1 (0 °)
    Vtx2 (180 °)
    CH 711 639 B1
    LÎCHTIMRJLS6REITE: 30ns
    ACTUAL DISTANCE [cm]
    CH 711 639 B1 ρ ·
    ->
    CH 711 639 B1 ¢ 2
    CH 711 639 B1
    CH 711 639 B1 l - w
    Ξ ïï iu o
    LU
    K s
    IS DISTANCE d
    0 dshort
    CH 711 639 B1
    CH 711 639 B1
    类似技术:
    公开号 | 公开日 | 专利标题
    CH711639B1|2018-05-15|Distance measuring method and distance measuring device.
    DE102010036964B4|2021-07-15|Delay compensation in a modulated optical time-of-flight phase estimation
    DE112012006401T5|2015-02-26|Area sensor and area image sensor
    DE212018000118U1|2019-08-26|LiDAR readout circuit
    DE112010003961T5|2012-12-06|Photoelectric conversion element, light receiving device, light receiving system and distance measuring device
    EP2629330B1|2018-02-28|Range sensor and range image sensor
    DE102010003843A1|2011-10-13|Distance measuring device with homogenizing measurement evaluation
    EP3185038A1|2017-06-28|Optoelectronic sensor and method for measuring a distance
    DE102013018789A1|2014-06-05|Controlling light-generated charge carriers
    DE112010003958T5|2012-12-06|A photoelectric conversion element, a light receiving device, a light receiving system and a distance measuring device
    DE112010003984B4|2019-01-24|Photoelectric conversion element, light receiving device, light receiving system and distance measuring device
    DE112015002711T5|2017-02-23|Distance measurement device
    CH712465B1|2018-09-28|Distance measuring device.
    DE102017101501B3|2018-01-04|An optoelectronic sensor and method for determining the distance of an object in a surveillance area
    DE102015217912A1|2017-03-23|Method for calibrating the runtime of a lidar sensor
    WO2012049885A1|2012-04-19|Range sensor and range image sensor
    WO2006045747A1|2006-05-04|Radiation detector for detecting radiation
    DE112013005141T5|2015-08-06|Distance sensor and distance image sensor
    DE102018117259A1|2019-04-04|GAP DETECTION SENSOR AND METHOD FOR OPERATING SUCH A SENSOR
    DE102011089642A1|2012-06-28|Light travel time sensor i.e. photo mixing detector-sensor, for three-dimensional time-of-light camera, has evaluation device determining distance value based on electrical parameters, where additional parameters are used to determine value
    DE112015001877T5|2017-01-12|Range imaging sensor
    DE112012005967T5|2014-11-13|Area sensor and area image sensor
    DE112017002292T5|2019-01-17|Distance sensor and control method of a distance sensor
    DE102020202764A1|2021-03-11|LIGHT DETECTING DEVICE AND ELECTRONIC DEVICE
    DE102018131581B4|2021-11-04|Method for distance measurement by means of a time-of-flight distance measurement system and a corresponding time-of-flight distance measurement system
    同族专利:
    公开号 | 公开日
    CN106574974A|2017-04-19|
    KR102350761B1|2022-01-13|
    US20170234983A1|2017-08-17|
    JP2016045066A|2016-04-04|
    KR20170044154A|2017-04-24|
    DE112015003846T5|2017-05-04|
    CN106574974B|2019-06-18|
    US10684371B2|2020-06-16|
    JP6280002B2|2018-02-14|
    WO2016027656A1|2016-02-25|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JP4235729B2|2003-02-03|2009-03-11|国立大学法人静岡大学|Distance image sensor|
    JP4280822B2|2004-02-18|2009-06-17|国立大学法人静岡大学|Optical time-of-flight distance sensor|
    JP2007121116A|2005-10-28|2007-05-17|Sharp Corp|Optical distance measuring device|
    JP5171158B2|2007-08-22|2013-03-27|浜松ホトニクス株式会社|Solid-state imaging device and range image measuring device|
    DE102009037596B4|2009-08-14|2014-07-24|Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.|Pixel structure, system and method for optical distance measurement and control circuit for the pixel structure|
    JP5558999B2|2009-11-24|2014-07-23|浜松ホトニクス株式会社|Distance sensor and distance image sensor|
    JP5675468B2|2011-03-31|2015-02-25|本田技研工業株式会社|Ranging system|
    JP5576851B2|2011-12-27|2014-08-20|本田技研工業株式会社|Ranging system and ranging method|
    JP6006514B2|2012-03-27|2016-10-12|浜松ホトニクス株式会社|Distance sensor and distance image sensor|
    WO2014119241A1|2013-01-31|2014-08-07|パナソニック株式会社|Distance measurement method and distance measurement system|
    KR102003496B1|2013-03-06|2019-10-01|삼성전자주식회사|Image Sensor and Image Pick Up Apparatus|
    EP2955539B1|2014-06-12|2018-08-08|Delphi International Operations Luxembourg S.à r.l.|Distance measuring device|EP3232224B1|2016-04-12|2018-06-13|Sick Ag|Distance-measuring opto-electronic sensor and method for detecting and determining the distance from objects|
    WO2020080065A1|2018-10-16|2020-04-23|株式会社ブルックマンテクノロジ|Distance measuring device, camera, and method for adjusting drive of distance measuring device|
    CN111025315B|2019-11-28|2021-11-19|奥比中光科技集团股份有限公司|Depth measurement system and method|
    JP2021099271A|2019-12-23|2021-07-01|ソニーセミコンダクタソリューションズ株式会社|Distance measuring device, control method therefor, and electronic apparatus|
    WO2021145090A1|2020-01-17|2021-07-22|パナソニックＩｐマネジメント株式会社|Ranging device|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    JP2014169166A|JP6280002B2|2014-08-22|2014-08-22|Ranging method and ranging device|
    PCT/JP2015/072048|WO2016027656A1|2014-08-22|2015-08-04|Ranging method and ranging device|
    [返回顶部]