Apparatus and method for detecting interface between core / cladding in optical waveguide blank

专利摘要:
The present invention relates to an apparatus and method for detecting the interface between air / coating and core / coating of a blank (preform) 13 used to make optical waveguide fibers. A beam of interfering light 30 is scanned across the blank 13, and the resulting spatial light intensity pattern (FIG. 5) is detected and analyzed. When the beam moves towards the center of the blank (FIGS. 5A and 5B) the interface between air / coating corresponds to a decrease in the width of the uniform spatial light intensity pattern. When the beam moves towards the center of the blank (FIGS. 5D and 5E) the interface between the core / coating at least corresponds to the generation of a dual spatial light intensity pattern. By rotating the blank and repeating the measurement at two or more angular positions, the concentricity and ellipticity of the blank can be measured.
公开号:KR19990030109A
申请号:KR1019980039759
申请日:1998-09-24
公开日:1999-04-26
发明作者:제랄드 리 햅번；프란시스카 엘 로리；데이비드 앤드류 파스텔；로버트 에스 와그너
申请人:알프레드 엘. 미첼슨；코닝 인코포레이티드；
IPC主号:

专利说明:

Apparatus and method for detecting interface between core / cladding in optical waveguide blank
TECHNICAL FIELD The present invention relates to optical waveguide fibers, and more particularly, to an apparatus and a method for detecting an interface between a core / coating of a blank used for producing the fiber.
As is well known in the art, optical waveguide fibers have a central core surrounded by a sheath, which core has a higher refractive index than the sheath. Such fibers are made by drawing the fibers from the blank by heating the ends of the blanks (known as preforms) and the diameter of the fibers is controlled at a drawing speed. As with the fibers, the blank has a high refractive index central core surrounded by a low refractive index coating, and of course, the core of the blank and the cross-sectional size of the coating are, for example, ten to one hundred times more than that of the core and the coating of the fiber. Bigger
For example, those skilled in the art can determine the geometric shape of a blank because various geometrical properties of the fiber, such as core / coated diameter ratios and core / coated concentricity, are determined by the corresponding geometric properties of the blank that is the material of the fiber draw. Various devices have been developed. One widely used device for measuring the diameter of blanks is the LASERMIC trademark, marketed by RazerMicro, Dayton, Ohio. The device works by illuminating the blank across the blank and then using an electronic camera to detect the outer edge of the shadow of the blank.
U.S. Patent 5,408,309 to Shimada et al. Describes the use of cross dimming to measure core / coated concentricity and blank ellipticity. The patent relates to measuring concentricity and ellipticity by rotating the blank and then detecting the position of the edges of the core and sheath with the angle of rotation with the electronic camera. Various equations are provided for analyzing camera records depending on whether the blank represents an elliptical and non-central core or just one of these drawbacks. In addition, an embodiment employing a laser light source is described, wherein the residual stress at the interface between the core and the coating layer is said to provide clear images to the layers.
In view of this, it is an object of the present invention to provide an improved technique for detecting the position of the interface between the core / cladding of the blanks used to make optical waveguide fibers. Another object of the present invention is to provide an improved technique for detecting the position of both the interface between the core / clad and the outer edge of the sheath. Another object of the present invention is to measure the concentricity between cores / coatings, the core ellipticity and the blank ellipticity by using the detected interface between the core / coating and the position of the outer edge of the coating. In addition to the known parameters relating to the fiber and its original use (especially the draw speed, the refractive index and the operating wavelength of the core and sheath), the core and sheath diameters, the mode field diameter (MFD) and the cutoff wavelength obtained from these measurements are described above. It can be predicted for the fiber.
In order to achieve these and other objects, the present invention
(a) providing a beam of interfering light, for example a laser beam;
(b) transversely scanning the beam across at least a portion of the blank;
(c) detecting light passing through the blank when the beam is scanned; And
(d) providing a method for detecting the interface between cores / coatings in a blank, comprising detecting the interface between cores / coatings by identifying the occurrence of a spatial intensity pattern in at least dual detected light.
In accordance with the present invention, it has been found that when the scanned laser beam enters the core of the blank from the sheath, a lobed diffraction / interference form of a spatial intensity pattern, ie at least a dual pattern, is produced. The pattern increases in intensity (and number of detectable lobes) as the beam moves into the core. Thus, by setting a threshold regarding the occurrence of such a pattern, the interface between the core / coating can be easily detected.
In a preferred embodiment, the interference beam of light is concentrated at a position corresponding to the nominal position of the blank longitudinal axis. That is, the beam is concentrated at the nominal position of the blank center. This concentration is known to increase the intensity of the lobe pattern created by the interface between the core / coating.
According to another feature of the invention,
(a) providing a detector capable of detecting a spatial light intensity pattern and a light source generating a beam of interfering light on opposite sides of the blank;
(b) transversely moving the beam across the blank when the detector detects a spatial light intensity pattern;
(c) identifying the edge of the sheath at the transverse position at which the width of the uniform spatial light intensity pattern decreases, at the moment the beam moves towards the longitudinal axis, preferably determined by a predetermined threshold; And
(d) A blank inspection method is provided at the moment the beam moves towards the longitudinal axis, preferably identifying the edge of the core in a transverse position at least in which the dual spatial light intensity pattern is determined, determined at a predetermined threshold.
If desired, the inspection method may comprise identifying the center of the horizontal position and the blank that the uniform spatial light intensity pattern is enclosed on both sides by at least the dual spatial light intensity pattern because of the transverse movement of the beam.
Using this inspection method, the edges of the sheath and the core are checked at the first angular position (after confirming the position), and then the blank is rotated at a predetermined angle, for example 90 °, and then the edge of the sheath and the core is checked again. By confirming the position, the core / coated concentricity, the coated ellipticity, and / or the core ellipticity can be measured. The data obtained in this way can be used to derive concentricity and / or ellipticity with respect to the axis position at which the measurement is made. Alternatively, instead of using only two measurements, complex measurements can be made at a series of angles.
Preferably, the inspection method is repeated at a plurality of axial positions along the length of the blank, at which point concentricity and / or ellipticity are measured.
In addition, the present invention
(a) blank support means, such as, for example, support rollers and belt systems, which can be used to rotate the blank about its longitudinal axis at a predetermined angle, contacting the blank from its bottom to its end;
(b) means for generating a beam of interfering light, such as, for example, a laser;
(c) means for concentrating the beam, such as, for example, a movable focal lens, near a nominal position of the blank longitudinal axis, which can be determined using, for example, the LASERMIC device described above;
(d) means for transversely scanning the beam across the blank, such as, for example, a robotic system using a direct current servomotor, to move the laser and focus lens in a plane perpendicular to the longitudinal axis of the blank;
(e) means for detecting a spatial light intensity pattern, such as, for example, a linear CCD camera; And
(f) the means for scanning transversely directs both the spatial light intensity pattern representing the air / coating interface and the pattern representing the core / coating interface onto the CCD camera when scanning the beam across the blank; Provided is a blank inspection device configured as means for directing light over the detection means, such as a lens system.
Advantageously, the robotic system can move the laser, focal lens, CCD camera and lens system along the length of the blank so that the geometry of the blank can change along the length of the blank.
1 is a schematic diagram of an apparatus that may be used in the practice of the present invention,
2-4 are schematic diagrams of lens systems that may be used in the practice of the present invention,
5A-5G illustrate spatial light intensity patterns generated when an interfering light beam scans a blank.
Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.
As described above, the present invention is directed to a method in which the beam of interfering light is directed to different regions of the blank (when aimed), through the change in the spatial light intensity pattern generated by the beam of interfering light between air / coating and core / coating. It is about identifying an interface.
1 is a schematic illustration of an apparatus that may be used to perform such verification. As shown in the figure, the blank 13 can be rotated about its longitudinal axis 15 as its end is supported. As preferred, the blank is shown horizontally supported in FIG. 1, but may also be used vertically if desired.
The measuring device 10 comprises (1) a light source 17, for example a 1.0 GHz laser diode that produces a collimated beam of interfering light, operates at 650 nm and is equipped with a quadruple beam expander; (2) a movable lens 19 for focusing the beam at the nominal center of the blank; (3) a detector (21) for detecting a spatial light intensity pattern generated by shining the beam onto a blank; (4) It consists of a lens system 23 which ensures that an important pattern reaches the detector 21 when the beam is scanned across the blank.
Furthermore, the device 10 preferably not only calculates the concentricity and ellipticity of the blank, but also filters and analyzes the output of the detector 21 to identify, for example, the air / coating and core / coating interfaces. As such, it includes a suitably programmed computer system (not shown) for processing the output. For example, the detected spatial light intensity pattern can be filtered and analyzed using commercially available software, such as sold under the trademark LABVIEW by National Instruments, Inc., Austin, Texas. In addition, the computer system must receive output from the robotic system with respect to the position of the laser beam so that the analyzed data from the detector can be related to the specific position of the blank.
In FIG. 1 for a schematic illustration of the robotic system, the parts 17, 19, 21, 32 are shown supported by the tables 25, 27. All the tables are movable in the y direction so that measurements can be made at different positions along the longitudinal direction of the blank 13. The table 25 is also movable in the x direction so that the light beam can scan laterally across the blank. Robotic systems commercially available and available from various vendors can be used in the practice of the present invention.
As noted above, the nominal center of the blank 13 can be measured using a LASERMIC or similar measuring device (not shown). If LASERMIC is used, the nominal center of the blank is taken as the midpoint of the covering shadow measured by the device. The device for obtaining the nominal center value can be carried by the robotic system so that the position of the nominal center can be adjusted as the measurement system moves along the length of the blank. Optionally, the nominal center value can be obtained in a separate laboratory, and the values can be provided to the computer system of the device 10.
Once the nominal center is measured, the position of the focus lens 19 is adjusted so that the distance Z between the focus lens and the nominal center satisfies the following expression (1).
Z = F- (n-1) R
Where F is the focal length of the focus lens, n is the refractive index of the coating, and R is the radius of the coating. In this way, the beam produced by the light source 17 is concentrated near the nominal longitudinal axis of the blank. This concentration has been found to improve signal strength in detector 21.
In particular, focusing on a focal point of approximately 20μ has been found to provide a significant improvement in signal strength. (Note that the beam produced by the light source 17 will generally not be circular. For example, a diode laser is known to produce an elliptical beam. In such a case, the major axis of the ellipse is preferably of the blank. The beam is perpendicular to the longitudinal axis (ie perpendicular to FIG. 1), and the size of the beam focused in this direction is preferably 20 μm or less. Preferably, the concentration is approximately 2 along the direction of the light beam (z direction in FIG. 1). It is kept at a distance of about mm. In fact, it has been found that a single lens element having a focal length of 150 mm and having a perforation larger than the diameter of the light beam in the lens is suitable for use as a beam focus lens.
2-4 illustrate a suitable lens system 23 for directing the spatial intensity pattern important to the detector 21. 2 shows a system before inserting a blank. As can be seen in the figure, the collimated light beam 30 is focused on the detector 21 even if it is on or off the axis, ie the detector is located at the focal point of the lens system.
3 and 4 show the operation of the system for small and large blanks, respectively. In these figures, the core of the blank is 32 and its coating is 34.
As shown in these figures, by combining the large lens elements 40, 42, 44 and the small lens elements 50, 52, the beam outside the sheath (upper beam in each figure) and just outside the core It is ensured that at least part of the beam 30 hits the detector 21 for detecting the beam on the side (low beam in each figure). Since these are the locations from which the most important data regarding the shape of the blanks are obtained, the figure shows that the five-element lens system in the blank size range achieves the goal of directing the important spatial intensity pattern to the detector.
In the lens system of Figs. 2 to 4, a suitable focal length and distance between the lenses (center to center) are as follows.
Lens elementsFocal Length (mm)Distance between lens (mm) 401000251405075 5050 421000 52100 44250
Here, the distance between the center of the lens element 40 and the longitudinal axis of the blank is 250 mm, the distance between the center of the lens element 44 and the detector 21 is 300 mm, and the detection area of the detector 21 is 16 mm. to be. The perforations of the lens elements are chosen large enough to capture the beam 30 because of the size of the blank to be inspected. More generally, the lens system 23 should have a large field of view capable of placing a sufficient light intensity pattern on the detector so that the outer edge of the sheath and the core / cladding interface can be seen.
5A-5G show the spatial light intensity pattern observed at detector 21 when beam 30 is scanned across the blank. The patterns in these figures were made using the apparatus of FIG. 1 and the lens system of FIGS. The output of the detector consisted of light intensity values for 2048 pixels.
5A and 5B show a uniform pattern when the light beam is on the outside of the coating (FIG. 5A) and when it hits the coating but does not enter completely inside (FIG. 5B). Comparison of these figures shows that the pattern width in FIG. 5B is smaller than the width in FIG. 5A. The decrease in width is due to the deflection of part of the beam from the detector by the sheath.
The width reduction between FIGS. 5A and 5B can be detected directly from the detector's output data, more conveniently by calculating the standard deviation of the data, the maximum of the pattern when the beam hits the sheath. Since the intensity does not increase, the decrease in the standard deviation coincides with the decrease in the pattern width. For example, by contrasting the reduction in the uniform pattern width by diameter measurement using an optional technique, such as the diameter measurement using the LASERMIC device described above, the limit of reduction that actually represents the same diameter value can be measured.
Optionally, a threshold large enough to avoid false detection of the edges of the sheath due to noise can be easily selected. In this latter case, the measurement of the diameter of the coating is made using the steps of the present invention, which is a substitute for its own standard.
5C shows the detector's output when the beam is inside the sheath but still far from the core edge. The sheath now deflects the entire beam so that substantially no light reaches the detector from the beam. Thus, the detector's output is essentially zero.
5D shows the detector's output when the beam is also inside the sheath but is now close to the core edge. Since the beam now strikes almost perpendicularly to the sheath, the uniform signal under this condition will regress, thus reducing the sheath's ability to deflect the beam away from the detector.
5E shows what happens when the beam hits the edge of the core. In this figure, the lobes on the sides are very thick, ie the pattern is no longer uniform and is now dual. As the beam continues to move into the core, both the strength of the pattern and its multiple features increase. Indeed, larger detectors and / or other lens systems 23 will indicate that the pattern includes a series of reduced intensity lobes, which is characteristic of the diffraction / interference form of the spatial light intensity pattern.
The lobe of FIG. 5E (as well as the lobe of FIG. 5F) consists of a center lobe and a first side lobe.
While not wishing to be bound by a particular theory of operation, the lobe pattern is believed to be due to a groove inside the core that acts as a diffraction grating to produce a diffractive / interfering spatial light intensity pattern, i.e., a pattern having a central lobe and a side lobe. In particular, it has been found that blanks without grooves inside the core do not produce a lobe pattern.
The size and specific location of the various lobes produced by the grooved blank may, among other factors, be described below between the radial spacing of the grooves including the uniformity of the spacings described below, at least to some extent within the grooves of any given groove. The change in refractive index connecting the grooves, including the uniformity of change, and again, to some extent, will depend on the radial area of each groove. Because of the large number of variability involved, core diameter measurements made at two circumferential positions 180 degrees apart may be somewhat different. For example, the measurement may vary by about 0.1 μ or more. While not wishing to be bound by a particular theory of operation, it is believed that this difference may be due to changes in the groove at different circumferential positions around the blank produced during the manufacturing process.
The occurrence of at least the dual pattern of FIG. 5E can be measured using various peak recognition techniques. One technique that has been found to work successfully actually consists of checking the area of the detector output at the location where the side lobe is expected to occur and setting the limit for this lobe with a combination of minimum height and maximum width. The threshold can be adjusted such that the core measurement is made on a blank that matches, for example, the core / coating concentricity, and the blocking wavelength measurement is made on the fibers drawn from the blank.
5F and 5G show the output from the detector when the beam is inside the core (FIG. 5F) and when it is at the core center (FIG. 5G). The comparison of FIG. 5E and FIG. 5F shows that the intensity of the peak increases as the beam enters the core further. 5G shows that at least the dual pattern exhibited by the detector is uniform when the beam is in line with the center of the core.
When the beam moves past the core center into the core body and then through the sheath and finally back into the air, the pattern of FIGS. 5A-5F is repeated in reverse order. This inverse pattern can be used to measure the position of the edges of the sheath and core relative to the lower half of the blank. Optionally, the beam can be redirected to a point below the blank and scanned upwards. The latter approach is preferred because the pattern will occur in the same order as shown in Figure 5, and therefore only one set of algorithms is needed for analysis.
Indeed, the systems of FIGS. 1-5 have been found to measure core and sheath shapes of blanks of various sizes very quickly. Measurements made with these systems have been found to relate to mode field diameter measurements, cutoff wavelengths and core / coating concentricity made on fibers drawn from blanks inspected using the apparatus and methods of the present invention. However, as described above, when the blank is measured in one direction and then rotated 180 ° and then measured, a slight change in the measured value is observed. If the above change is contrary to the particular application of the present invention, it can be adjusted, for example, by continually directing the blank in one direction using the acyclic symmetry characteristic associated with one end of the blank.
Although specific embodiments of the invention have been described and illustrated, it will be appreciated that changes may be made without departing from the spirit and scope of the invention. In addition to the foregoing, for example, other light sources, lenses (eg, aspherical lenses), detectors (including multiple detectors), software programs, and the like can be used in the practice of the present invention. Similarly, instead of moving the light source, the beam can be scanned across the blank, for example using a multi-facet rotating mirror. Also, rather than using an electronic detection system, the spatial light intensity pattern of the present invention can be manually viewed on the observation screen. Similarly, various blank holding devices can be used in the practice of the present invention, including various devices for rotating the blank and for holding the blank in a vertical or horizontal direction.
Various other changes will be apparent to those skilled in the art from the teachings herein without departing from the spirit and scope of the invention. The following claims are intended to cover such modifications, changes and equivalents as well as the specific embodiments described herein.
As mentioned above, an apparatus and method for detecting the interface between core / coating in an optical waveguide blank according to the present invention is characterized by the use of a blank to determine various geometrical properties of the fiber, such as core / coating diameter ratio and core / coating concentricity. The geometric properties can be easily detected and inspected to avoid waste of raw materials and to reduce defect rates in the textile manufacturing process.

权利要求:
Claims (22)
[1" claim-type="Currently amended] A method for detecting an interface between a core / coating in a blank used to manufacture optical waveguide fibers,
The blank has a longitudinal axis,
The method is
(a) providing a beam of interfering light;
(b) transversely scanning the beam across at least a portion of the blank;
(c) detecting light passing through the blank when the beam is scanned; And
(d) detecting the interface between the core / coating by identifying the occurrence of a spatial intensity pattern in at least dual detected light, wherein the interface between the core / coating in the blank.
[2" claim-type="Currently amended] The method of claim 1 wherein the longitudinal axis has a nominal position and the beam is concentrated near its nominal position.
[3" claim-type="Currently amended] 10. The method of claim 1, wherein step (c) comprises providing an optical system to direct light passing through the blank to the detector.
[4" claim-type="Currently amended] The method of claim 1 wherein a threshold is used to confirm said occurrence.
[5" claim-type="Currently amended] The interface between core and cladding according to claim 1, characterized in that the method consists of rotating the blank around the longitudinal axis and additional steps of repeating steps (a) to (d) for the rotated blank. Method for Detecting
[6" claim-type="Currently amended] 10. The method of claim 1, comprising an additional step of repeating steps (a) to (d) at a plurality of locations along the longitudinal axis.
[7" claim-type="Currently amended] A method for measuring the position of an interface between a core / coating in a blank used to make an optical waveguide fiber,
The blank has a longitudinal axis,
The method is
(a) providing a beam of interfering light;
(b) transversely scanning the beam across at least a portion of the blank;
(c) detecting the light passing through the blank as a role of the transverse position of the beam; And
(d) the transverse position of the beam in the generation corresponds to the position of the interface between the core / cladding in the blank, wherein the blank consists of confirming the occurrence of a spatial intensity pattern in the detected light that is at least dual Method for measuring the position of the interface between core / cladding.
[8" claim-type="Currently amended] 8. The method of claim 7, wherein the longitudinal axis has a nominal position and the beam is concentrated near its nominal position.
[9" claim-type="Currently amended] 8. The method of claim 7, wherein step (c) comprises providing an optical system to direct light passing through the blank to the detector.
[10" claim-type="Currently amended] 8. A method according to claim 7, wherein a threshold is used to confirm the occurrence.
[11" claim-type="Currently amended] 8. The interface between core and cladding according to claim 7, characterized in that the method consists of rotating the blank around the longitudinal axis and further steps (a) to (d) for the rotated blank. Method for measuring the position of.
[12" claim-type="Currently amended] 8. A method according to claim 7, comprising an additional step of repeating steps (a) to (d) at a plurality of locations along the longitudinal axis.
[13" claim-type="Currently amended] In the blank inspection method used for optical waveguide fiber production,
The blank has a core, sheath and longitudinal axis,
The method is
(a) providing a detector capable of detecting a spatial light intensity pattern and a light source generating a beam of interfering light on opposite sides of the blank;
(b) transversely moving the beam across the blank when the detector detects a spatial light intensity pattern;
(c) identifying the edge of the sheath in a transverse position at which the width of the uniform spatial light intensity pattern decreases as the beam moves toward the longitudinal axis; And
and (d) checking the edges of the core in a horizontal position at which the double spatial light intensity pattern appears at the moment the beam moves toward the longitudinal axis.
[14" claim-type="Currently amended] 14. The method of claim 13, wherein the method comprises the further step of identifying the center of the blank in a horizontal position where both sides of the uniform spatial light intensity pattern are surrounded by at least the dual spatial light intensity pattern as the beam moves laterally. Blank inspection method.
[15" claim-type="Currently amended] 14. The blank inspection of claim 13, wherein the method comprises the steps of rotating the blank about its longitudinal axis at a predetermined angle and additional steps of repeating steps (a) to (d) for the rotated blank. Way.
[16" claim-type="Currently amended] 16. The method of claim 15, wherein the method comprises the further step of measuring core / coating concentricity from intrinsic and repeat confirmation of steps (a) to (d).
[17" claim-type="Currently amended] 16. The method of claim 15, wherein the method comprises the further step of measuring the blank ellipticity from the intrinsic and repeated confirmation of step (c).
[18" claim-type="Currently amended] 16. The method of claim 15, wherein the method comprises the further step of measuring the core ellipticity from the eigen and repeat confirmation of step (d).
[19" claim-type="Currently amended] 14. The method of claim 13, further comprising repeating steps (a) through (d) at a plurality of locations along the longitudinal axis.
[20" claim-type="Currently amended] 14. The method of claim 13, wherein the longitudinal axis has a nominal position and the beam is concentrated near its longitudinal axis.
[21" claim-type="Currently amended] 14. A method according to claim 13, wherein an optical system is provided in step (a) for directing light passing through the blank to the detector.
[22" claim-type="Currently amended] In the blank inspection apparatus used for optical waveguide fiber manufacture,
The blank has a longitudinal axis with a nominal position,
The device is
(a) blank support means;
(b) means for generating a beam of interfering light;
(c) means for concentrating the beam near a nominal position of the longitudinal axis;
(d) means for transversely scanning the beam across the blank;
(e) means for detecting a spatial light intensity pattern; And
and (f) means for directing light over said detection means when said means for scanning laterally scans a beam across a blank.

类似技术:

---

公开号 | 公开日 | 专利标题

---

US20150067929A1|2015-03-05|Illumination for optical scan and measurement

---

JP5593347B2|2014-09-24|Circular wire optical defect detection apparatus and optical defect detection method

---

EP0686842B1|2003-09-24|Ophtalmic lens inspection with a double focus illumination

---

US7454052B2|2008-11-18|Pixel based machine for patterned wafers

---

EP1106993B1|2013-05-15|Glass-container neck-finish check detection

---

US4597665A|1986-07-01|Dual collector optical flaw detector

---

DE60025221T2|2006-07-13|Optical inspection system for parts in the subpixel area

---

KR100322326B1|2002-07-02|Inspection system with in-lens off-axis illuminator

---

EP1346310B1|2018-11-28|Repetitive inspection system with intelligent tools

---

CN104568389B|2018-01-12|Bilateral dislocation differential confocal component parameters measuring method

---

JP3936220B2|2007-06-27|Edge inspection equipment

---

US7092105B2|2006-08-15|Method and apparatus for measuring the three-dimensional surface shape of an object using color informations of light reflected by the object

---

EP1913520B1|2017-05-24|An apparatus and method for detecting surface defects on a workpiece such as a rolled/drawn metal bar

---

KR100481118B1|2005-09-07|Scanning method and system for inspecting anomalies on surface

---

DE3034903C2|1990-04-19|

---

KR100380711B1|2003-07-16|Variable Spot Size Scanning Device

---

US7110106B2|2006-09-19|Surface inspection system

---

AU658669B2|1995-04-27|Measurement method and apparatus

---

CN101598685B|2013-11-06|Apparatus and method for imaging at least part of sample

---

US4223346A|1980-09-16|Automatic defect detecting inspection apparatus

---

US4882497A|1989-11-21|Method and apparatus of measuring outer diameter and structure of optical fiber

---

US4872757A|1989-10-10|Optical convex surface profiling and gauging apparatus and method therefor

---

EP0599297B1|1998-05-20|Method of detecting impurities in molten resin

---

US5627638A|1997-05-06|Method and apparatus for detecting defects in lenses

---

DE3822303C2|1991-04-11|

同族专利:

---

公开号 | 公开日

---

CN1246611A|2000-03-08|

---

BR9805127A|1999-11-03|

---

US6025906A|2000-02-15|

---

CA2247552A1|1999-03-25|

---

EP0905477A3|2000-08-09|

---

JPH11183316A|1999-07-09|

---

ID21421A|1999-06-10|

---

AU8423898A|1999-04-15|

---

AU733224B2|2001-05-10|

---

EP0905477A2|1999-03-31|

引用文献:

---

公开号 | 申请日 | 公开日 | 申请人 | 专利标题

---

法律状态:
1997-09-25|Priority to US6067997P

---

1997-09-25|Priority to US60/060,679

---

1998-09-24|Application filed by 알프레드 엘. 미첼슨, 코닝 인코포레이티드

---

1999-04-26|Publication of KR19990030109A

优先权:

---

申请号 | 申请日 | 专利标题

---

US6067997P| true| 1997-09-25|1997-09-25|

---

US60/060,679|1997-09-25|