JP2009222485A - Optical sensor device and its installation state confirming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To conform the installation state of an optical sensor device without requiring complicated work. <P>SOLUTION: In the optical sensor device, the difference between a measuring image (an image in a state that foreign matter 51 is arranged on a work 50) photographed in the CCD of a light receiver 4 and a reference image (an image in a state that the foreign matter 51 is not arranged on the work 50) is calculated and the image based on the difference is displayed. A worker judges, for example, whether the presence of the foreign matter 51 appears in the difference between both images on the basis of the displayed image to judge whether the optical axes of a floodlight projector 3 and the light receiver 4 are aligned with each other at this point of time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical sensor device, and more particularly to an optical sensor device that detects a foreign object or the like existing in a detection region by projecting light to the detection region and receiving the light, and a method for confirming the installation state thereof. About.

  Conventionally, as an optical sensor device, parallel light is projected from a light projector to a detection region, and the presence or absence of a foreign object is detected based on a change in the total amount of light received by the light receiver when the parallel light is received by the light receiver. The device is being used.

  As an example of such a device, in Patent Document 1, a foreign object is moved relative to a projector and a light receiver, and the amount of light received by the light receiver by crossing the foreign object in the optical path of parallel light emitted from the projector. A technique for detecting the presence or absence of a foreign substance based on the presence or absence of a change is disclosed.

  In such an apparatus, specifically, as shown in FIG. 12, for example, the laser beam having a width L0 projected from the projector 300 propagates in parallel on the substrate 500 and is detected by the photodetector 400. The The substrate 500 is an inspection object to be inspected for whether or not a foreign substance is attached, and is held on a stone surface plate 510. In FIG. 12, the propagation direction of the laser beam is indicated by an arrow DZ. The substrate 500 is moved relative to the projector 300 and the light receiver 400 together with the stone surface plate 510. The moving direction is a direction perpendicular to the arrow DZ and the arrow DY (vertical direction), and is a direction perpendicular to the paper surface.

  As shown in FIG. 13, when the foreign object 501 exists on the substrate 500, a part of the parallel light projected by the projector 300 is blocked by the foreign object 501. Thereby, the width of the light detected by the light receiver 400 theoretically decreases by L1 from L0. As a result, the total amount of received light detected by the light receiver 400 decreases. Based on such a change in the total amount of received light, the presence or absence of a foreign object or the like is detected.

  Patent Document 2 discloses a technique for dividing the light receiving area of the light receiver in the horizontal direction and detecting the presence or absence of foreign matter on the substrate based on the amount of light received in each divided area.

Specifically, as shown in FIG. 14, the parallel light 200 is projected from the projector 300 toward the light receiver 400 in the direction indicated by the arrow DZ, and the substrate 500 is directed toward the projector 300 and the light receiver 400. In the system that is relatively moved in the horizontal direction as indicated by A, the light receiving area of the light receiver 400 is divided so as to be aligned in the horizontal direction, which is the moving direction of the substrate 500.
JP 2002-1195 A JP 2006-351441 A

  In the optical sensor device as described above, it is necessary to align the so-called optical axes of the projector and the light receiver, but the distance from the light projecting part of the light projector to the light receiving region of the light receiver is relatively long, and When the area becomes small, in such a work, considerable accuracy (for example, accuracy of about 50 seconds as the projection angle of the projector) may be required for focusing the projection by the projector. There is a problem that complicated work is complicated.

  If the optical axes of the light projector and the light receiver do not match, the detection sensitivity when optically detecting a foreign substance is lowered as described above.

  In addition, since a specific means for determining whether or not the optical axis is correct has not been established, it often takes a long time to determine that the optical axis has been adjusted to such an extent that foreign matter can be detected. This is also a factor that complicates the optical axis alignment work.

  Further, since the index indicating the state of the optical axis has not been established, the state of the optical axis cannot be left as objective data. For this reason, at the time of maintenance of the optical sensor device, it has not been possible to confirm whether the optical axis has changed since the start of installation.

  In addition, the conventional optical sensor device needs to confirm where the light is projected from the light projector in the light receiving area of the light receiver in the device in order to confirm the state of the optical axis of the light projector and the light receiver. That is, it is necessary for the worker to go to the installation place of the optical sensor device, and there is a problem that it is complicated.

  As described above, in the conventional optical sensor device, since the optical axis alignment of the projector and the light receiver is complicated, there is a problem that a complicated work is required to check the installation state.

  The present invention has been conceived in view of such circumstances, and an object of the present invention is to make it possible to confirm the installation state of the optical sensor device without requiring complicated work.

  An optical sensor device according to the present invention includes a light projecting unit and pixels distributed in a two-dimensional region, and receives the light projection from the light projecting unit to output a received light amount distribution in the two-dimensional region. To enable a light receiving unit, a reference value storage unit that stores a reference value related to the amount of light received by each pixel in the two-dimensional area of the light receiving unit, and adjustment of the optical axis of the light projecting unit and the light receiving unit And a display unit for displaying an image of a difference with respect to a value stored in the reference value storage unit with respect to a received light amount distribution of the light receiving unit.

  Further, the optical sensor device of the present invention includes a detection unit that detects the presence or absence of an object between the light projecting unit and the light receiving unit based on the amount of light received in a measurement region that is a part of the light receiving region of the light receiving unit. And a designation unit that accepts designation of the measurement region.

  In the optical sensor device according to the aspect of the invention, it is preferable that the measurement region includes a plurality of regions in which the amount of received light can be calculated independently of each other.

  Further, the optical sensor device of the present invention includes a detection unit that detects the presence or absence of an object between the light projecting unit and the light receiving unit based on the amount of light received in a measurement region that is a part of the light receiving region of the light receiving unit. It is preferable to further include a setting unit that sets the measurement area so that the measurement area has a lower end at the lowest position where the difference exceeds a threshold value in the measurement area.

  In the optical sensor device of the present invention, a predetermined number of pixels exceeding the set value input to the input unit in an input unit that receives an input of a set value for the difference and an image displayed by the display unit It is preferable to further include a determination unit that determines whether or not the set value is appropriate based on whether or not the value is present.

  In the optical sensor device of the present invention, it is preferable that the display unit further displays the value of the difference on a specific line in the image.

  The optical sensor device of the present invention includes an optical axis changing unit that changes an optical axis of the light projecting unit and the light receiving unit, a received light amount storage unit that stores a received light amount distribution in the light receiving unit, and the optical axis. An optical axis determination unit that determines a preferable state of the optical axis from the plurality of states by detecting a received light amount distribution in the light receiving unit in each state in which the optical axis is changed to a plurality of states by the changing unit. The optical axis determining unit further includes a plurality of states of the optical axis by the optical axis changing unit in a state where a test piece is disposed between the light projecting unit and the light receiving unit. A light reception amount for measurement, which is a light reception amount distribution by the light receiving unit when the light is projected onto the light unit, is detected, the light reception amount for measurement is stored in the light reception amount storage unit, and the light projecting unit and the light receiving unit In a state where the test piece is not disposed between, the optical axis changing unit Therefore, for each of the plurality of states of the optical axis, a received light amount for reference that is a received light amount distribution by the light receiving unit when the light projecting unit projects light, and the received light amount for reference is stored in the received light amount A difference for each pixel of the corresponding measurement light reception amount and the reference light reception amount for each of the plurality of states of the optical axis, and the plurality of states among the plurality of states In the difference calculated for each of the above, the state of the preferable optical axis includes a state in which the difference between the maximum value and the maximum value of the difference on the line intersecting the horizontal direction in the light receiving region of the light receiving unit is the largest Is preferably determined.

  An optical sensor device installation state confirmation method according to the present invention includes a light projecting unit that projects parallel light and pixels distributed in a two-dimensional region, and receives light projected from the light projecting unit. An optical sensor device comprising a light receiving unit that outputs a received light amount distribution of the two-dimensional region, an installation state confirmation method for enabling optical axis adjustment of the light projecting unit and the light receiving unit, A step of detecting a light receiving amount for measurement, which is a light receiving amount distribution in the light receiving unit when the light projecting unit projects light with a test piece disposed between the light projecting unit and the light receiving unit; and the measurement Storing the received light amount in the storage unit, and receiving light in the light receiving unit when the light projecting unit projects light in a state where the test piece is not disposed between the light projecting unit and the light receiving unit. A step of detecting a received light amount for reference which is a quantity distribution; The step of storing the received light amount for reference in the storage unit, the step of calculating the difference between each pixel of the received light amount for measurement and the received light amount for reference, and causing the display device to display an image based on the calculated difference. And a step.

  According to the optical sensor device of the present invention, in order to enable adjustment of the optical axes of the light projecting unit and the light receiving unit, an image of the difference between the light receiving amount distribution of the light receiving unit and the reference value for each pixel is displayed. Is done.

  Thereby, the operator who is going to adjust the optical axis of a light projection part and a light-receiving part in an optical sensor apparatus can judge the light reception mode in a light-receiving part based on the displayed difference image. For this reason, by giving objective information about the optical axis adjustment, the worker can evaluate the state of the optical axis at that time based on the information. Therefore, it is possible to reduce the burden related to the determination when the worker performs the work for adjusting the optical axis, and it is possible to shorten the time required for the optical axis adjustment.

  Further, according to the optical sensor device of the present invention, the image can be left as an index representing the state of the optical axis at that time.

  Therefore, the state of the optical axis can be left as objective data, so that it is possible to confirm whether the optical axis has changed since the start of installation during maintenance of the optical sensor device. become able to.

  Further, according to the optical sensor device of the present invention, the worker can confirm the state of the optical axis by viewing the difference image displayed by the display unit.

  Therefore, it is not necessary for the worker to go to the place where the optical sensor device is installed only for checking the state of the optical axis, thereby reducing troublesome work.

  As described above, the optical sensor device of the present invention can confirm the installation state without requiring complicated work.

  According to the method for confirming the installation state of the optical sensor device of the present invention, the received light amount for measurement, which is the received light amount in a state where the test piece is arranged between the light projecting unit and the light receiving unit, and the test piece are arranged An image based on the difference of the received light amount distribution in the light receiving unit from the received light amount for reference that is the received light amount in the absence of the image is displayed.

  Thereby, the worker displays whether or not the state of the optical axis in the optical sensor device at that time can reflect the presence or absence of the test piece as a difference between the received light amount for reference and the received light amount for measurement. An objective determination can be made based on the obtained image.

  Therefore, according to the present invention, it is possible to give objective information on the suitability of the state of the optical axis to the worker, and to greatly facilitate the work of adjusting the optical axis by the worker. it can.

  Hereinafter, an optical sensor device according to an embodiment of the present invention will be described with reference to the drawings. It should be noted that the same components are denoted by the same reference symbols in the respective drawings, and detailed description thereof will not be repeated.

[First Embodiment]
FIG. 1 is a block diagram showing the overall configuration of an optical sensor device according to the present invention, and FIG. 2 is a configuration diagram showing the arrangement of projectors and light receivers when this optical sensor device is applied to foreign object detection. is there.

  The optical sensor device 1 according to the present embodiment includes a light projector 3 that projects parallel light 2 onto a work 50 that is an inspection object such as a glass substrate, a light receiver 4 that receives the parallel light 2, and 2 and a signal processing device 6 for determining the presence / absence of a foreign substance 51 on the workpiece 50 by signal processing the output of the projector 4. The projector 3 and the light receiver 4 are connected to the workpiece 50 by an arrow A in FIG. As shown, the foreign object 51 existing on the workpiece 50 while being moved is detected based on the change in the received light amount distribution in the light receiver 4. The foreign matter 51 is not limited to the case where the foreign object 51 exists on the work 50 but can be detected even when the surface of the work 50 rises and is shielded from light. The workpiece 50 such as a glass substrate that has been inspected for the presence or absence of the foreign matter 51 is coated with a film forming material on the surface thereof by a coating device (not shown).

  The projector 3 includes a semiconductor laser 8 driven by a laser driving circuit 7, a collimating lens 9 that collimates light from the semiconductor laser 8, and a slit 10 having an opening 10 </ b> A. The parallel light 2 is projected.

  On the other hand, the light receiver 4 includes a CCD (charge-coupled device) 11 that is a two-dimensional light receiving element, and the signal processing device 6 samples the pixel signal read from the CCD 11 as shown in FIG. A sample / hold (S / H) circuit 12 for holding, an A / D converter 13 for A / D (analog / digital) conversion of the output of the sample / hold circuit 12, and A / D converted pixel data are stored. Of the image memory 14, a CPU (central processing unit) 15 having a function as a detection unit for detecting the presence or absence of a foreign object (object) based on the pixel data of the image memory 14, and A liquid crystal display unit 16 that displays a captured image by the CCD 11 based on pixel data, and various operation keys 17 as operation means are provided.

  3 and 4 show a block configuration of the optical sensor device 1 of the present embodiment. 3 shows a state where the foreign matter 51 does not exist on the work 50 disposed between the projector 3 and the light receiver 4, and FIG. 4 shows a state where the foreign matter 51 exists on the work 50.

  With reference to FIGS. 3 and 4, in optical sensor device 1, the laser light projected from light projector 3 propagates in parallel on workpiece 50 and is detected by light receiver 4. In particular, as shown in FIG. 4, when a foreign object 51 exists on the workpiece 50, a part of the parallel light projected by the projector 3 is blocked by the foreign object 51.

  The signal processing device 6 includes a measuring device 601 that detects a received light amount distribution in the light receiver 4, and a comparison calculator 602 that performs processing such as storage of the received light amount detected by the measuring device 601 and comparison with a past received light amount. And a display 603 for displaying various information such as a measurement result in the measuring instrument 601 and a result of processing by the comparison computing unit 602.

  The measuring instrument 601 includes the S / H circuit 12 and the A / D converter 13, the comparison calculator 602 includes the image memory 14 and the CPU 15, and the display 603 includes the liquid crystal display unit 16. It may be realized as a hardware function or may be realized by the CPU 15 executing specific software. Each component operates based on information input to the operation key 17 as appropriate.

  The opening 10A of the slit 10 of the projector 3 is formed in a rectangular shape that is long in the moving direction of the projector 3 and the light receiver 4 (in the direction of arrow A in FIG. 2), for example, a rectangle of 1 mm × 5 mm. The parallel light 2 is projected onto the surface of the light receiver 4 on which the CCD 11 is provided. The distance from the slit 10a to the CCD 11 is, for example, 4.0 m.

  In the present embodiment, the measurement area of the CCD 11 (area where the amount of received light can be measured) is, for example, 3.2 mm × 3.46 mm, but 2 mm × 3 in consideration of the optical axis alignment between the projector 3 and the light receiver 4. It is preferable that it is 2 mm or more.

  In the present embodiment, the workpiece 50 moves relative to the projector 3 and the light receiver 4 in the direction of arrow A. The moving speed is set so that the relatively moving foreign object 51 can capture the pixel signal in the CCD 11 at least once after reaching the position facing the measurement area of the CCD 11 and passing through the area. In the present embodiment, the width along the moving direction of the measurement region of the CCD 11 is set to 3 mm, for example, and the maximum moving speed is set to 400 mm / s, for example. Note that the image signal capturing period of the CCD 11 is set to 7.0 ms, for example.

  Next, in the optical sensor device 1, the contents of processing executed when adjusting the optical axes of the projector 3 and the light receiver 4 will be described. The adjustment of the optical axis of the projector 3 and the light receiver 4 includes the alignment of the light so that the light projected from the projector 3 can be received by the light receiver 4. FIG. 5 is a flowchart of the optical axis adjustment process. In the optical axis adjustment process, the received light amount distribution of the light projected on the workpiece 50 to which the foreign object 51 is not attached is detected, and the dummy 50 is attached to the foreign object (test piece 51). The received light amount distribution of the projected light is detected, and an image based on the difference in the received light amount of each pixel in these received light amount distributions is displayed and used for evaluation of optical axis adjustment.

  Referring to FIG. 5, in the optical axis adjustment process, first, as step S <b> 10, an operator performs adjustment so that the direction of light projected by the semiconductor laser 8 of the projector 3 is parallel to the stone surface plate or the workpiece 50. Then, the projector 3 and the light receiver 4 are aligned so that the light reaches the CCD 11 of the light receiver 4.

  Next, as step S20, the signal processing device 6 executes a process of displaying a difference image on the liquid crystal display unit 16 (difference image display process), and the process proceeds to step S30. The contents of the difference image display process in step S20 will be described with reference to FIG. 6 which is a flowchart of the subroutine of the process.

  With reference to FIG. 6, in the differential image display process, first, in step S <b> 21, the measuring instrument 6 moves the parallel light in the direction of arrow A onto the work 50 to which the foreign matter 51 is not attached, and receives the amount of light received by the CCD 11. Is measured (the image is taken in), and step S22 proceeds to processing.

  In step S21, when the parallel light 2 moves from one end to the other end in the arrow A direction of the workpiece 50, an image photographed by the CCD 11 is captured every 7.0 ms.

  Next, in step S22, the measuring device 6 transfers the image captured in step S21 to the comparison operation unit 602 as a reference image, and the process proceeds to step S23.

  In step S23, the reference image transferred in step S22 is stored in the image memory 14 by the comparison calculation unit 602, and the process proceeds to step S24.

  In step S24, a dummy foreign substance (test piece 51) is set on the work 50 by the operator, and the process proceeds to step S25. In the present embodiment, the size of the test piece 51 is, for example, about 100 μm or more in diameter. Further, the worker executes step S24 after the process of step S23 is completed. Therefore, when the process of step S23 is completed, it is preferable that the fact is notified in the liquid crystal display unit 16.

  In step S25, when the parallel light 2 moves from one end to the other end of the workpiece 50 in the arrow A direction, an image photographed by the CCD 11 is captured every 7.0 ms.

  Next, in step S26, the measuring instrument 6 transfers the image captured in step S25 to the comparison calculation unit 602 as a measurement image, and the process proceeds to step S27.

  In step S27, the measurement image transferred in step S26 is stored in the image memory 14 by the comparison calculation unit 602, and the process proceeds to step S28.

  In step S28, the comparison calculation unit 602 calculates a density difference between corresponding pixels of the reference image and the measurement image, and the process proceeds to step S29.

  In step S29, the comparison calculation unit 602 displays the calculation result of the density difference in step S28 on the display unit 603, and the process returns to FIG.

An example of an image displayed on the display unit 603 in step S29 is shown in FIG.
Referring to FIG. 7, on screen 700, an image showing the density difference calculated in step S28 is displayed in display column 710.

  Specifically, in the display field 711, the density difference for the entire measurement region of the CCD 11 is shown as a color image (monochrome in the drawing). The display color in the display column 711 is displayed based on the correspondence between the display color and the density difference shown in the display column 740. That is, the CPU 15 (comparison operation unit 602) converts the differences for all the pixels in the entire measurement area of the CCD 11 into color pixels based on the correspondence shown in the display field 740, and causes the display field 711 to display them. ing.

  Further, in the present embodiment, in step S23 and step S25, images are taken a plurality of times, and in step S28, the difference in density difference between images corresponding to the positional relationship between the parallel light 2 and the work 50 is calculated. However, in step S29, an image showing the density difference between the images having the largest difference values is displayed.

In the display column 711, section indication lines 712 and 714 are displayed.
The cross-section indicating line 712 is displayed to indicate the horizontal cross-sectional position, and the cross-section indicating line 714 is displayed to indicate the vertical cross-sectional position. On the screen 700, the distribution of difference values for the cross section indicated by the cross section indicating line 712 is shown in the concentration distribution display field 713. In addition, the distribution of difference values for the cross section indicated by the cross section indicating line 714 is shown in the density distribution display column 715.

  The CPU 15 (comparison operation unit 602) can change the position in the display column 711 of each of the cross-section instruction line 712 and the cross-section instruction line 714 based on the operation content for the operation key 17. Further, the CPU 15 (comparison operation unit 602) displays the distribution of difference values for the cross section corresponding to the positions of the changed cross-section indicating lines 712 and 714 in the density distribution display fields 713 and 715.

  In the display column 711, a frame 710A is displayed. The optical sensor device 1 may be configured to detect the presence or absence of the foreign matter 51 on the workpiece 50 based on the amount of received light in a part of the measurement area of the CCD 11. In such a case, the frame 710 </ b> A displays an area (effective measurement area) used when detecting the presence or absence of the foreign object 51 in the measurement area of the CCD 11.

  The CPU 15 (comparison operation unit 602) can change the display position in the display field 711 of the frame 710A based on the operation content with respect to the operation key 17, and according to this, on the actual work 50 The position (range) in which the amount of received light in the measurement area of the CCD 11 used in the detection process of the presence or absence of the foreign object 51 can be changed. That is, the operator can designate an effective measurement area by operating the operation key 17 in the optical sensor device 1.

  In the optical sensor device 1, the value input by the operation key 17 can be used as a difference threshold for determining the presence or absence of the foreign object 51. However, the CPU 15 (comparison operation unit 602) In step 711, whether or not the threshold value can be used for determining the presence or absence of the foreign object 51 is determined based on whether or not there is a specific number of pixels exceeding the input threshold value, and the determination result is matched with the screen 700. Can be displayed.

  In addition, the CPU 15 (comparison operation unit 602) performs edge detection using a predetermined value as a threshold for the difference value displayed in the display field 711, and among the edges detected by the edge detection. The effective measurement area can be set according to the lowest one.

  Note that the CPU 15 causes the display field 720 to display the reference image used for calculating the difference value displayed in the display field 711, and causes the display field 730 to display the measurement image used for calculating the difference value. be able to.

  Returning to FIG. 5, after the difference image display process in step S <b> 20, in step S <b> 30, whether or not the optical axes of the light projector 3 and the light receiver 4 are aligned by the operator based on the screen as shown in FIG. 7. If it is determined that further adjustment is necessary, the process proceeds to step S40. If it is determined that adjustment is not necessary, the optical axis adjustment process ends.

  In step S40, as in step S10, the operator aligns the light projector 3 and the light receiver 4 (adjusts the light projection axis of the light projector 3) so that the light reaches the CCD 11 of the light receiver 4. After being performed, the process returns to step S20.

  In the present embodiment described above, in the optical sensor device, a measurement image (an image in which the foreign object 51 is disposed on the work 50) and a reference image (on the work 50) taken by the CCD 11 of the light receiver 4 are used. The difference (for each corresponding pixel) of the image in which no foreign object 51 is arranged is calculated, and an image based on the difference is displayed on the liquid crystal display unit 16. Based on the image, the operator determines, for example, whether or not the presence or absence of the foreign object 51 appears in the difference between the two images, so that the optical axes of the projector 3 and the light receiver 4 at that time match. It can be determined whether or not.

  Note that the difference image displayed in the display field 711 in FIG. 7 can be stored in the image memory 14 by appropriately operating the operation key 17. Thereby, the state of the optical axes of the projector 3 and the light receiver 4 at that time can be stored as objective data.

  Further, in the optical sensor device 1 of the present embodiment, as shown in FIG. 8, a color image based only on the reference image can be displayed.

  Referring to FIG. 8, an image based on the image density of the reference image for the entire measurement area of CCD 11 is displayed in color (monochrome in the drawing) in display field 811 of screen 800. Note that the display color in the display column 811 is displayed based on the correspondence between the display color shown in the display column 840 and the density difference. That is, the CPU 15 (comparison operation unit 602) converts the received light density in the reference image of the entire measurement area of the CCD 11 into color pixels based on the correspondence shown in the display field 840 and causes the display field 811 to display it. ing.

In the display column 811, cross-section indicating lines 812 and 814 are displayed.
The cross-section indicating line 812 is displayed to indicate the horizontal cross-sectional position, and the cross-section indicating line 814 is displayed to indicate the vertical cross-sectional position. In the screen 800, the distribution of received light density for the cross section indicated by the cross section indicating line 812 is shown in the density distribution display field 813. Further, the distribution of received light density for the cross section indicated by the cross section indicating line 814 is shown in the density distribution display column 815.

[Second Embodiment]
FIG. 9 is a block diagram showing the overall configuration of the optical sensor device of the present invention, and FIG. 10 is a diagram schematically showing the block configuration of the optical sensor device.

  With reference to FIG. 9 and FIG. 10, the optical sensor device 1 of the present embodiment controls the light projection angle of the semiconductor laser 8 of the projector 3 with respect to the optical sensor device 1 of the first embodiment. An optical axis driving unit 7A is further provided.

  FIG. 11 is a flowchart of optical axis adjustment processing executed in the optical sensor device 1 of the present embodiment.

  Referring to FIG. 11, in the optical axis adjustment process, first, as step SA10, the operator adjusts the direction of light projected by the semiconductor laser 8 of the projector 3 to be parallel to the stone surface plate or the workpiece 50. Then, the projector 3 and the light receiver 4 are aligned so that the light reaches the CCD 11 of the light receiver 4.

  In step SA20, when the parallel light 2 moves from one end to the other end in the arrow A direction of the work 50, an image photographed by the CCD 11 is captured every 7.0 ms.

  Next, in step SA30, it is determined whether or not step SA20 has been executed at all pre-stored projection angles for the semiconductor laser 8, and if so, the process proceeds to step SA50. If it is determined that this is not the case, the process proceeds to Step SA40.

  In step SA40, the comparison calculator 602 changes the projection angle of the semiconductor laser 8 to the optical axis driving unit 7A by the unit angle θ, and the process returns to step SA20.

  The reference image is captured and stored while the projection angle of the semiconductor laser 8 is changed by the angle θ by the processing of Step SA20 to Step SA40.

  In step SA50, a dummy foreign substance (test piece 51) is set on the work 50 by the operator, and the process proceeds to step SA60.

Next, in step SA60, the projection angle of the semiconductor laser 8 is initialized.
In Step SA70 to Step SA90, the measurement image is captured and stored while the projection angle of the semiconductor laser 8 is changed by the angle θ with the test piece 51 installed on the workpiece 50.

  In step SA100, the comparison calculator 602 calculates a difference for each corresponding pixel between the reference image and the measurement image for each projection angle.

  Next, in step SA110, the difference between the peak value (maximum value) and the bottom value (minimum value) of the difference in the Y-axis direction (vertical direction) is the largest difference among the projection angles by the comparison calculator 602. A large projection angle is specified.

  Then, in step SA120, the comparison calculator 602 displays the difference image of the projection angle specified in step SA110 on the display 603 as shown in FIG.

  Then, the specified projection angle and the difference image for the projection angle are stored in the image memory 14, and the optical axis adjustment process ends.

[Other variations]
In each of the embodiments described above, the CCD is employed as the light receiving element in the light receiver 4. However, the light receiving element is not limited to this, and a MOS (Complementary Metal Oxide Semiconductor) or the like can also be employed.

  Further, in each of the embodiments described above, the measuring instrument 601, the comparison computing unit 602, and the display unit 603 constituting the signal processing device 6 may be realized as hardware functions, or the CPU 15 stores specific software. It may be realized by executing. Note that these may be realized by executing specific software in a general-purpose computer, or may be configured by specific hardware devices. Further, for example, the comparison calculator 602 and the display 603 can be realized by a general-purpose computer, and the measuring instrument 601 can be realized by a specific signal processing device.

  In each of the embodiments described above, an example in which the optical sensor device is applied to detection of a foreign substance on a glass substrate has been described. However, the aspect in which the optical sensor device of the present invention is applied is limited to this. It is also considered that the present invention can be applied to foreign object detection for sheet-like inspection objects such as film, metal, and paper. In addition, it is considered that the present invention can be applied not only to foreign object detection but also to detection of other objects such as yarn fluff.

  Each embodiment disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. In addition, it is intended that the techniques disclosed in the embodiments are applied in combination as much as possible, including modifications.

1 is a block diagram illustrating an overall configuration of an optical sensor device according to a first embodiment of the present invention. It is a block diagram which shows arrangement | positioning of a light projector and a light receiver at the time of applying the optical sensor apparatus of FIG. 1 to a foreign material detection. It is a figure which shows typically the block structure of the optical sensor apparatus of FIG. It is a figure which shows typically the block structure of the optical sensor apparatus of FIG. It is a flowchart of the optical axis adjustment process performed in the optical sensor apparatus of FIG. It is a flowchart of the subroutine of the difference image display process of FIG. It is a figure which shows an example of the screen displayed on the liquid crystal display part of the optical sensor apparatus of FIG. 1 by the process of FIG. It is a figure which shows the other example of the screen displayed on the liquid crystal display part of the optical sensor apparatus of FIG. 1 by the process of FIG. It is a block diagram which shows the whole structure of the optical sensor apparatus which is the 2nd Embodiment of this invention. It is a figure which shows typically the block configuration of the optical sensor apparatus of FIG. 10 is a flowchart of optical axis adjustment processing executed in the optical sensor device of FIG. 9. It is a figure for demonstrating the foreign material detection by a prior art. It is a figure for demonstrating the foreign material detection by a prior art. It is a figure for demonstrating the foreign material detection by a prior art.

Explanation of symbols

  1 optical sensor device, 2 parallel light, 3 projector, 4 light receiver, 4A detection surface, 6 signal processing device, 7 laser drive circuit, 8 semiconductor laser, 9 collimating lens, 10 slit, 10A aperture, 11 CCD, 12 samples Hold circuit, 13 A / D converter, 14 Image memory, 15 CPU, 16 Liquid crystal display, 17 Operation keys, 40 Measurement area, 41-44, 41A-46A Divided area, 50 workpieces, 51 Foreign material, 510 Stone surface plate .

Claims (8)

A light projecting unit;
A light receiving unit that includes pixels distributed in a two-dimensional region, and outputs a received light amount distribution of the two-dimensional region by receiving light projected from the light projecting unit;
A reference value storage unit that stores a reference value for the amount of light received by each pixel in the two-dimensional region of the light receiving unit;
In order to enable adjustment of the optical axis of the light projecting unit and the light receiving unit, a display unit that displays an image of a difference with respect to a value stored in the reference value storage unit with respect to a received light amount distribution of the light receiving unit is provided. Optical sensor device. A detection unit that detects the presence or absence of an object between the light projecting unit and the light receiving unit based on the amount of light received in a measurement region that is a part of the light receiving region of the light receiving unit;
The optical sensor device according to claim 1, further comprising a designation unit that accepts designation of the measurement region.   The optical sensor device according to claim 2, wherein the measurement region includes a plurality of regions in which the amount of received light can be calculated independently of each other. A detection unit that detects the presence or absence of an object between the light projecting unit and the light receiving unit based on the amount of light received in a measurement region that is a part of the light receiving region of the light receiving unit;
The optical according to any one of claims 1 to 3, further comprising a setting unit configured to set the measurement region so that a lower end is located at the lowest position where the difference exceeds a threshold value within the measurement region. Type sensor device. An input unit that accepts an input of a set value for the difference;
5. The image processing apparatus according to claim 4, further comprising: a determination unit configured to determine suitability for the set value based on whether or not a predetermined number or more of pixels exceeding the set value input to the input unit are present in the image displayed by the display unit. The optical sensor device according to 1.   The optical sensor device according to claim 1, wherein the display unit further displays a value of the difference on a specific line in the image. An optical axis changing unit that changes an optical axis of the light projecting unit and the light receiving unit;
A received light amount storage unit for storing a received light amount distribution in the light receiving unit;
Light that determines a preferable state of the optical axis from among the plurality of states by detecting a received light amount distribution in the light receiving unit in each state in which the optical axis is changed to a plurality of states by the optical axis changing unit. An axis determining unit,
The optical axis determination unit is
The light receiving unit when the light projecting unit projects light on each of the plurality of states of the optical axis by the optical axis changing unit with a test piece disposed between the light projecting unit and the light receiving unit. Detect the amount of light received for measurement, which is the received light amount distribution by
Storing the received light amount for measurement in the received light amount storage unit;
When the test piece is not disposed between the light projecting unit and the light receiving unit, the light axis changing unit projects light to the light projecting unit for each of the plurality of states of the optical axis. Detecting a reference received light amount that is a received light amount distribution by the light receiving unit,
Storing the received light amount for reference in the received light amount storage unit;
For each of the plurality of states of the optical axis, calculate a difference for each pixel of the corresponding measurement light reception amount and the reference light reception amount,
Among the plurality of states, in the difference calculated for each of the plurality of states, the difference between the maximum value and the maximum value of the difference on the line in the direction intersecting the horizontal direction in the light receiving region of the light receiving unit is the largest. The optical sensor device according to claim 1, wherein a state including an object is determined as the preferable state of the optical axis. A light projecting unit that projects parallel light; and a light receiving unit that includes pixels distributed in a two-dimensional region and outputs a received light amount distribution in the two-dimensional region by receiving light projected from the light projecting unit. About an optical sensor device, an installation state confirmation method for enabling optical axis adjustment of the light projecting unit and the light receiving unit,
Detecting a received light amount for measurement which is a received light amount distribution in the light receiving unit when light is projected to the light projecting unit with a test piece disposed between the light projecting unit and the light receiving unit;
Storing the amount of received light for measurement in a storage unit;
Detecting a received light amount for reference, which is a received light amount distribution in the light receiving unit when the light projecting unit projects light in a state where the test piece is not disposed between the light projecting unit and the light receiving unit. When,
Storing the received light amount for reference in a storage unit;
Calculating a difference for each pixel of the measurement light reception amount and the reference light reception amount;
And a step of displaying an image based on the calculated difference on a display device.