• 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 method for generating the light radiation, in particular for tracking a linear textile material, wherein the source of the light radiation is a light-emitting diode (1). During the duration of the generation of the light radiation by the light-emitting diode (1), the voltage dropping across the light-emitting diode (Ud) is tapped off and the size of the feed current (Id) is set as a function of the tapped voltage. Thus, the influence of the temperature of the light emitting diode (1) on the intensity of this light radiation is eliminated. The invention also relates to an electrical circuit for driving a light emitting diode (1), wherein the anode of the light emitting diode (1) is connected to the output of the operational amplifier (2) and the cathode of the light emitting diode (1) via a series resistor (R3) to the is connected to the negative pole of the feed, wherein the light-emitting diode (1) a first resistor (R1) which is switched between the anode of the light-emitting diode (1) and the negative input of the operational amplifier (2), and a second resistor (R2), the between the negative input of the operational amplifier (2) and the cathode of the light emitting diode (1) is connected in parallel, and where the positive input of the operational amplifier (2) is connected to the voltage (Ui) for adjusting the operating point of the radiation source, wherein in this way, the supply current (Id) for the light-emitting diode (1) in dependence on the voltage across the light-emitting diode (1) voltage is regulated such that the egg nfluss the temperature of the light emitting diode (1) on the intensity of the light emitted from the light emitting diode (1) light radiation (1) is eliminated.
    公开号:CH707089B1
    申请号:CH01690/13
    申请日:2013-10-01
    公开日:2018-05-15
    发明作者:Stusak Miroslav
    申请人:Rieter Cz Sro；
    IPC主号:
    专利说明:

    description
    TECHNICAL FIELD The invention relates to a method for generating the light radiation in an optical sensor system, which is used in particular to track the presence and / or the quality of a linear textile material, and wherein the system as a source for the light radiation is a light emitting diode and the Includes radiation sensor receiving light radiation.
    The invention further relates to an electrical circuit for controlling the light emitting diode, which is used in an optical sensor system, which is used primarily for tracking the presence and / or the quality of a linear textile material.
    PRIOR ART The known radiation sources use light-emitting diodes to generate the light radiation in a visible and invisible spectrum and are used for various types of sensors, for example on textile machines. These radiation sources are usually loaded with a certain dependence of the emitted light energy on the ambient temperature or also on the temperature of the chip emitting its own heat. In general, as the temperature of the light-emitting diode rises, the voltage at the junction PN decreases in the transmissive direction, which causes the light energy emitted to depend on the temperature of the radiation source, approximately linearly in the temperature range used in practice.
    This phenomenon can be compensated for, for example, by a well-known but complicated method using a temperature or light sensor and current regulator of the light-emitting diode, as is stated, for example, in CN 102 158 083.
    The further known possibility consists in the use of a source of constant voltage with a defined internal resistance for supplying the light-emitting diode, when when the light-emitting diode is heated to lower the voltage on its transition and thereby to the current increase, which has a compensating effect, like it for example JPS 63 236 387 describes.
    Similarly, the supply of the light emitting diode works from the source of a constant current with a defined internal conductivity.
    However, these two methods cause a large power loss on the internal resistance or conductivity of the sources used, which means in practice that the voltage source must deliver a much higher voltage or the current source must deliver a much higher current than it Reaching the required emitted light energy of the light emitting diode would be essential.
    The aim of the invention is to propose such a method for generating the light radiation and an electrical circuit for such a light emitting diode, in which the emitted light energy would not be dependent on the ambient temperature and on the own temperature of the light emitting diode.
    Statement of the nature of the invention The object of the invention is achieved by the method according to the invention for generating the light radiation, the essence of which is that during the period of generation of the light radiation by the light-emitting diode the voltage drop across the light-emitting diode is tapped and the tapped Voltage determines the size of the feed current which flows through the light-emitting diode, the dependency of the feed current on the voltage being set such that the influence of the temperature of the light-emitting diode on the intensity of the light radiation of the light-emitting diode is eliminated by the regulation thus implemented.
    The advantage is that the temperature of the intensity of the light emitted by the light emitting diode is largely independent of temperature, and this in a very simple manner: the voltage on the own light emitting diode is used directly for compensation purposes, as if this light emitting diode itself is a sensor for temperature sensing would be, and therefore no further sensors and controllers are necessary. In contrast to the prior art, it is no longer necessary to provide a considerably higher current or a significantly higher voltage than would be necessary to achieve the required intensity of the light radiation, there is no loss of energy due to the compensation, and therefore it is not necessary to design the source of the LED excessively powerful.
    The voltage is preferably supplied to a negative pole of an operational amplifier, to the positive pole of which a voltage for setting the operating point of the radiation source is connected, and the dependence of the size of the supply current on the falling voltage is set by a suitable choice of the size of resistors ,
    The regulation of the feed current as a function of the tapped voltage preferably also takes into account that the radiation sensor also has a temperature dependency.
    CH 707 089 B1 The advantage lies in the fact that the temperature behavior of the entire optical sensor system can be compensated for in this way by means of the radiation source according to the invention, that is to say it can be suitably adjusted, and this with any radiation sensor in the corresponding optical sensor system.
    The aim of the invention is also achieved by the inventive electrical circuit for driving a light-emitting diode, the essence of which is that the anode of the light-emitting diode is connected to the output of an operational amplifier and the cathode of the light-emitting diode via a resistor in series to the negative Pol of the supply is connected, the light emitting diode in parallel with a first resistor, which is connected between the anode of the light emitting diode and a negative input of the operational amplifier, and a second resistor, which is connected between the negative input of the operational amplifier and the cathode of the light emitting diode are, and wherein the positive input of the operational amplifier is connected to the voltage for setting the operating point of the radiation source, in this way the supply current for the light-emitting diode is regulated as a function of the voltage drop across the light-emitting diode such that the influence of the temperature of the light-emitting diode on the intensity of the light radiation emitted by the light-emitting diode is eliminated.
    The advantage is in particular the simplicity of operation without requiring additional energy consumption in that the light-emitting diode itself is used as a temperature sensor, with the possibility, on the one hand, of only the temperature dependence of the radiation source itself and / or the temperature dependence of the radiation sensor of the optical Compensate sensor system. In principle, the electrical circuit with the light-emitting diode also functions in the same way in the case of a plurality of light-emitting diodes in the series and / or in the regime of an interrupted light.
    It is advantageous if the radiation sensor has an optical CMOS line sensor, or is designed as such.
    Explanation of the drawings [0017] The exemplary embodiment of the device according to the invention is shown in the accompanying drawing, in which:
    1 shows a basic electrical circuit for controlling the light-emitting diode as the radiation source of an optical sensor system,
    2 shows an electrical circuit of the light-emitting diode in the yarn sensor,
    3 shows a graph which shows the dependency of the voltage Ud with a constant current on the one hand and the current Id from the temperature with a constant intensity of the radiation from the light-emitting diode on the other hand,
    FIG. 4 shows a graph which shows the dependence of the voltage Ud with constant current on the one hand and the current Id from the temperature with decreasing intensity of the radiation from the light-emitting diode on the other hand
    5 shows a graph which illustrates the temperature compensation in the optical sensor system with the light-emitting diode as the radiation source and the optical CMOS sensor.
    Exemplary embodiments of the invention The exemplary embodiment of the electrical circuit of the radiation source with the light-emitting diode, which is shown in FIG. 1, represents the principle of the invention. The anode of the light-emitting diode 1 is connected to the output 21 of the operational amplifier 2, and the cathode of the light-emitting diode 1 is connected to the negative pole of the supply via a resistor in series R3. A first resistor R1 and a second resistor R2 are connected in parallel to the light-emitting diode 1. The first resistor R1 is connected between the anode of the light-emitting diode 1 and the negative input of the operational amplifier 2. The second resistor R2 is connected between the cathode of the light-emitting diode 1 and the negative input of the operational amplifier 2. The positive input of the operational amplifier 2 is connected to the potential Ui for setting the operating point of the radiation source.
    The light emitting diode 1, which is provided in the optical sensor system as a radiation source, is fed with a feed current Id, the size of which depends not only on the potential Ui, but also on the voltage Ud falling across the transition PN of the light emitting diode, the Voltage Ud is temperature dependent. In the electrical circuit according to the invention, the degree of influence of the temperature-dependent voltage Ud on the feed current Id for the light-emitting diode 1 can be set very simply in such a way that the resulting radiated light energy of the light-emitting diode 1 decreases or increases with the temperature, in particular in such a way that it is temperature-independent in a certain range without there being a significant increase in the current or the voltage required to emit the desired light energy.
    From the general principle of a feedback amplifier, it follows that
    Ui = Ur + Ud.R2 / (R1 + R2), where it holds that Ur = ld.R3 where
    CH 707 089 B1
    Ui input voltage, the temperature-dependent voltage that drops across the LED, and
    Id is the current that flows from the output of the operational amplifier.
    Then applies after the regulation
    Id = UÌ / R3 - Ud.R2 / R3 (R1 + R2), what one calls for simplicity
    Id = a.Ui - b.Ud, where a and b are resistance constants, where a = 1 / R3, b = R2 / R3 (R1 + R2).
    If one neglects the current via R1 and R2, one can describe Id as current that flows through the light-emitting diode 1, and from the above-mentioned proportion Id = a.Ui - b.Ud one can then conclude that the current Id , which flows through the LED 1, consists of the heat-independent constant value a.Ui, which is given by the input voltage Ui according to the required emitted light energy, and the component -b.Ud, which depends on the heat-dependent voltage on the LED 1 is. In general, the current flowing through the light-emitting diode 1 increases as the temperature-dependent voltage Ud falls under the influence of the temperature, and the circuit thus compensates. The suitable choice of the resistance constants a, b for the respective temperature characteristics of the light-emitting diode 1 can cause the light energy emitted by the light-emitting diode 1 to decrease or increase with the rising temperature of the light-emitting diode 1, or the function of this temperature to increase using a local extreme is independent of a certain range of linearity.
    As far as we assume from the above relation that
    Id = a.Ui - b.Ud where the chosen resistance constants a, b contain a physical quantity regarding the conductivity, and we know that the voltage Ud on the light-emitting diode 1 generally decreases with the temperature, it is possible to do this like express as follows:
    Ud = Udo - c.At, where Ud 0 is the voltage on the LED 1 at a rest temperature, c is a constant of the temperature influence, the unit of measurement of the constant being [mV / ° C] and At being the change in temperature.
    After insertion into the basic relation, this results
    Id = a.Ui-b. (Udo-c.At), so
    Id = a.Ui - b. Ud 0 + bc At, which is a straight line equation that indicates that the current Id flowing through the LED 1 increases with the temperature when the voltage is switched on when the voltage on the LED 1 decreases with the temperature. And the voltage drops because that is a property of the LED 1.
    And since you can keep the emitted light output of the light emitting diode 1 of the electrical power consumption for proportional, so Ud.ld, in the reduction of the voltage Ud on the light emitting diode 1 by the temperature influence of the current Id through the light emitting diode, so that Power remains the same, which the electrical circuits mentioned in the respective application achieve.
    From Fig. 3 it can be seen how the voltage Ud on the light-emitting diode 1 decreases with the temperature - dashed line what is given by the material of the light-emitting diode 1, concrete values corresponding to a red light-emitting diode. The dash-dotted line naturally shows in other units of measure how the respective current Id must increase with the temperature so that the intensity INT of the radiation of the light-emitting diode 1, shown with the solid line, is constant, that is to say is independent of the temperature. In practice there are of course small deviations from this simplifying linearity.
    FIG. 4 also illustrates the state that the choice of the resistance constants a, b sets the course of the current Id1 with a smaller curve steepness as a function of the temperature than is the case with the current Id from FIG. 3 , which is necessary to maintain the constant intensity of the radiation from the light-emitting diode 1. The course of the current Id1 with a smaller slope is shown by the double-dashed line. The current Id1 increases with the temperature less than with it the respective voltage Ud on the light-emitting diode 1, and the result is a reduction in the intensity INT of the radiation of the light-emitting diode 1 with the increasing temperature, which is represented by the solid line.
    The light emitting diode 1 is usually a component of the optical sensor system (sensing device), in particular as a source for the light radiation in an optical sensor system for tracking, which also has a light receiver, which is provided for example by an optical CMOS line sensor. The optical sensor itself also has a certain temperature dependency in its sensitivity. In the case of an optical CMOS line sensor, for example, fluctuation currents increase with the temperature, and thus its sensitivity increases as the temperature increases, so the CMOS sensor indicates a higher radiation intensity with the rising temperature than it actually does
    CH 707 089 B1 is given. The sensitivity of the CMOS sensor is shown in FIG. 5 by a dotted line. So that the optical sensor system as a whole is temperature-independent, the light-emitting diode 1 must therefore generate such light radiation, the intensity of which INT decreases with the temperature in a defined manner. If the resistance constants a, b and the course of the intensity INT of the radiation as a function of the temperature according to FIG. 4 are suitably set, which is shown in FIG. 5 with a solid line, the constant temperature dependence of this entire optical sensor system is obtained is shown in Fig. 5 with a double solid line.
    In Fig. 4, in which a light emitting diode 1 is shown, which is provided according to the invention in the optical sensor system for evaluating the yarn quality on the textile machine, the voltage Ui on the input Inp in the range 0-5 V provides an input variable Setting the emitted target light energy of the light emitting diode 1, and in this case this is represented by the current Id in the range 2-20 mA, which flows through the light emitting diode 1. The second input Stb of the operational amplifier 2 is used in the respective application for the controlled periodic switching off of the current of the light-emitting diode 1.
    The advantage of the method described above for generating the light radiation and the radiation source for its execution is, among other things, that it requires a less large current or a less large voltage than the LED 1 itself for the compensation of the temperature dependence appropriate intensity of light radiation is required. The input for supplying the potential Ui for setting the target intensity remains stable. The voltage Ui, which is usually set by a processor or by another element, merely specifies the radiation intensity around which the respective compensation should take place. With this circuit, the intensity of the light radiation increases with the increase Ui.
    Industrial Applicability The invention can be used in sensor systems which operate on an optical principle and which use a light-emitting diode as their light source, for which certain temperature properties are required, especially in sensor systems for tracking the presence and / or the quality of the linear textile materials, which are advantageously equipped with an optical CMOS line sensor.
    权利要求:
    Claims (8)
    [1]
    claims
    1. A method for generating the light radiation in an optical sensor system, which is used in particular to track the presence and / or the quality of a linear textile material, and wherein the optical sensor system comprises a light-emitting diode (1) as a source for the light radiation and a radiation sensor receiving the light radiation , characterized in that during the period of generation of the light radiation by the light-emitting diode (1) the voltage (Ud) dropping across the light-emitting diode (1) is tapped and in that the tapped voltage (Ud) determines the magnitude of the feed current (Id) which is caused by the light-emitting diode (1) flows, the dependence of the supply current (Id) on the voltage (Ud) being set such that the influence of the temperature of the light-emitting diode (1) on the intensity of the light radiation from the light-emitting diode (1) is achieved by the control thus implemented is eliminated.
    [2]
    2. The method according to claim 1, characterized in that the voltage is fed to a negative pole of an operational amplifier (2), to the positive pole of which a voltage (Ui) for setting the operating point of the radiation source is connected, with a suitable choice of the size of Resistors (R1, R2, R3) the dependency of the size of the supply current (Id) on the falling voltage (Ud) is set.
    [3]
    3. The method according to claim 2, characterized in that the regulation of the feed current (Id) as a function of the tapped voltage (Ud) additionally takes into account that the radiation sensor also has a temperature dependency.
    [4]
    4. Electrical circuit for controlling a light-emitting diode (1), which is used in an optical sensor system, which is used in particular to track the presence and / or the quality of a linear textile material, characterized in that an anode of the light-emitting diode (1) to the Output of an operational amplifier (2) is connected and a cathode of the light-emitting diode (1) is connected to the negative pole of the feed via a resistor (R3) connected in series, the light-emitting diode (1) being a first resistor (R1) connected between the Anode of the LED (1) and the negative input of the operational amplifier (2) is connected, and a second resistor (R2), which is connected between the negative input of the operational amplifier (2) and the cathode of the LED (1), are assigned in parallel , and wherein the positive input of the operational amplifier (2) is connected to the voltage (Ui) for setting the operating point of the radiation source In this way, the feed current (Id) for the light-emitting diode (1) is regulated as a function of the voltage drop across the light-emitting diode (1) such that the influence of the temperature of the light-emitting diode (1) on the intensity of the light-emitting diode (1) emitted light radiation (1) is eliminated.
    [5]
    5. Electrical circuit according to claim 4, characterized in that the operational amplifier (2) is provided with an input (Stb) for controlled interruption of the supply current of the light-emitting diode (1).
    [6]
    6. Electrical circuit according to one of claims 4 or 5, characterized in that the electrical circuit has at least two light-emitting diodes (1) which are connected in series.
    CH 707 089 B1
    [7]
    7. Optical sensor system with an electrical circuit according to one of claims 4 to 6 for tracking the presence and / or the quality of the yarn, in which an optical CMOS line sensor is provided as a radiation receiver.
    [8]
    8. Application of the method according to one of claims 1 to 3 in an optical sensor system for tracking the presence and / or the quality of the yarn, in which an optical sensor has an optical CMOS line sensor as a radiation receiver.
    CH 707 089 B1
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    同族专利:
    公开号 | 公开日
    CH707089A2|2014-04-15|
    DE102013110817A1|2014-04-17|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CS150390B1|1970-10-09|1973-09-04|
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    CS235114B1|1981-08-26|1985-05-15|Jan Bydzovsky|Operational amplifier's temperature compensation connection|
    JPS63236378A|1987-03-25|1988-10-03|Hitachi Seiko Ltd|Light-emitting diode lighting circuit|
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    US7781983B1|2007-07-20|2010-08-24|Vimicro Corporation|Closed-loop feedback circuit for controlling LEDs|
    DE102009052390A1|2009-11-09|2011-05-12|Ledon Lighting Jennersdorf Gmbh|Method and circuit arrangement for generating mixed LED light of predetermined color|
    CN102158083B|2011-04-22|2013-05-01|复旦大学|BUCK converter for stabilizing output light flux of LED |DE102017128370A1|2017-11-30|2019-06-06|Bundesdruckerei Gmbh|Temperature and intensity calibrated reference light source|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    CZ2012-672A|CZ2012672A3|2012-10-02|2012-10-02|Method of generating light radiation and connection of LED radiation source LED in optical sensor for monitoring linear textile material|
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