JP4989993B2 - Edge detecting device and light flux adjusting method thereof - Google Patents

Description

  The present invention relates to an optical edge detection device that receives a monochromatic light beam emitted from a projector by a light receiver and detects an edge position of a measurement object that blocks the monochromatic light beam, and a method for adjusting the light beam.

  FIG. 7 is a diagram illustrating a configuration of a conventional edge detection device disclosed in Patent Document 1. In FIG. In FIG. 7, the edge detection apparatus includes a line sensor 100, a projector 101, and an edge detection unit 102. The line sensor 100 has a plurality of light receiving cells (pixels) arranged at a predetermined pitch in a certain direction, and receives the monochromatic parallel light emitted from the projector 101. The projector 101 is disposed to face the light receiving surface of the line sensor 100, and includes a light source 101a including a laser diode (LD), an optical fiber 101b, and a projector lens 101c.

  In the projector 101, the monochromatic light (laser light) generated by the light source 101a is guided to the projector lens 101c through the optical fiber 101b, converted into a monochromatic parallel light beam by the projector lens 101c, and then applied to the line sensor 100. Irradiated. When the measurement object 104 passes through the measurement space 103 formed between the projector 101 and the light receiving surface of the line sensor 100, the monochromatic parallel light applied to the line sensor 100 is shielded. The edge detection unit 102 is configured by a microcomputer, and detects the edge position in the arrangement direction of the light receiving cells of the measurement object 104 that analyzes the output of the line sensor 100 and shields the monochromatic parallel light in the measurement space 103.

  The detection of the edge position of the measurement object 104 by the edge detection unit 102 is a change in the total amount of light received by the line sensor 100 or the measurement object caused by the measurement object 104 blocking a part of the monochromatic parallel light beam in the measurement space 103. This is done by analyzing a light receiving pattern caused by Fresnel diffraction occurring at the edge portion of the object 104. In this way, the conventional edge detection apparatus detects the edge position of the measurement object 104 with high accuracy according to the light intensity distribution on the light receiving surface of the line sensor 100.

JP 2004-177335 A

  Since the conventional edge detection apparatus is configured as described above, if all the light receiving cells of the line sensor 100 are irradiated with monochromatic parallel light, the measurement is performed by the width of the line sensor 100 in the light receiving cell arrangement direction. The object 104 can be detected. However, considering the individual differences between components in manufacturing the edge detection device, the monochromatic light emission position (the emission surface position of the optical fiber 101b) in the projector 101 is the focal position of the projection lens 101c in all products. It is difficult to make them coincident to make perfect parallel light.

  Therefore, in the conventional edge detection apparatus, there may be a case where the monochromatic light is spread by the light projecting lens 101c to be wider than the width of the line sensor 100 in the light receiving cell arrangement direction due to manufacturing variations.

  FIG. 8 is a diagram illustrating a case where the monochromatic light beam is expanded by the light projecting lens beyond the width of the light receiving cell arrangement direction of the line sensor, and the measurement object 104 moves in a direction crossing the optical path of the monochromatic light in the measurement space 103. Shows the case. In FIG. 8A, the measurement object 104b moves on the line sensor 100 side of the measurement space 103, and the edge is disposed at the end of the line sensor 100 at the position in the movement direction in FIG. The monochromatic light to be received by the light receiving cell 105 is blocked.

  On the other hand, the measurement object 104a has a distance B from the edge position to the light receiving surface of the line sensor 100 larger than the measurement object 104b, and moves on the light projecting lens 101c side of the measurement space 103. In this case, as shown in FIG. 8A, the measurement object 104a does not block the monochromatic light to be received by the line sensor 100 even at the same movement direction as the measurement object 104b. That is, the measurement object 104a does not block the monochromatic light to be received by the light receiving cell 105 of the line sensor 100 unless the measurement object 104a further moves by a distance C as shown in FIG.

  Accordingly, when the monochromatic light beam is spread by the light projecting lens 101c beyond the width of the line sensor 100 in the light receiving cell arrangement direction, the measurement object 104a closer to the light receiving surface of the line sensor 100 is measured than the measurement object 104b. The line sensor 100 cannot be detected unless it moves in the space 103 to a position further advanced in the moving direction.

  FIG. 9 is a graph showing the measurement result of the movement amount of the edge position with respect to the movement amount of the measurement object by the edge detection apparatus in FIG. 8, and shows the result of the measurement object moving on the light projecting lens side of the measurement space. ing. In FIG. 9, a case where the width of the light receiving cell arrangement direction of the line sensor 100 is 30 mm is taken as an example, and if the monochromatic parallel light is irradiated from the light projecting lens 101c to the light receiving cell of the line sensor 100, When the reference position is set to 0 mm, the edge of the measurement object 104 moving along the line sensor 100 in the measurement space 103 can be up to a position 30 mm away from the reference position. Note that the reference position of the moving stage of the measurement object 104 is the position of each lower end of the measurement objects 104a and 104b shown in FIG.

  However, in this edge detection apparatus, as described above, if the measurement object 104a that moves on the light projection lens 101c side as compared with the measurement object 104b does not move to a position further advanced in the measurement space 103, the line sensor 100 cannot detect an edge. For this reason, as shown in FIG. 9, even if the moving stage of the measuring object 104a is moved from 0 mm to 30 mm, the moving amount (edge moving amount) of the measuring object 104a is only measured by 28 mm, and the front and rear are 1 mm. Each measurement error occurs. That is, since the reference position of the moving stage of the measuring object 104 is the lower end position of each of the measuring objects 104a and 104b shown in FIG. 8A, in the case of the measuring object 104a, until the measurement is started. An unmeasurable area occurs at 1 mm before the measurement space 103 and 1 mm deep before passing through the measurement space 103, making it impossible to measure the amount of movement the measurement object 104 has actually moved.

  As described above, in the conventional edge detection apparatus, the measurement start position may be shifted even if the measurement object 104 is similarly moved due to the positional relationship of the measurement object 104 in the measurement space 103. This tendency becomes more prominent when there is an individual difference for each product in the width of the line sensor 100 in the light receiving cell arrangement direction, and the measurement object 104 depends on the positional relationship between the measurement object 104, the projector 101, and the line sensor 100. A measurement error occurs between the movement amount.

  The present invention has been made to solve the above-described problems, and is capable of reliably detecting a measurement object within the measurement space regardless of the position of the measurement object within the measurement space. The object is to obtain a detection device.

  Another object of the present invention is to provide a light beam adjustment method for an edge detection device that can adjust the degree of convergence of a monochromatic light beam irradiated from a projector to a light receiver by a simple operation.

An edge detection apparatus according to the present invention includes a light receiver having a line sensor in which a plurality of light receiving cells are arranged, a light source that generates monochromatic light, and monochromatic light from the light source in a predetermined range from parallel to the optical axis. This occurs at the edge portion of the measurement object generated by the projector having a projection lens that converts the converged monochromatic light beam into a line sensor and projects it onto the line sensor, and the measurement object blocks a part of the monochromatic light beam in the measurement space. An edge detection unit that detects an edge position of the measurement object by analyzing a light reception pattern caused by Fresnel diffraction is provided.

  In the edge detection apparatus according to the present invention, the projector operates the first stage on which the light source is mounted so that the monochromatic light emitting portion of the light source faces the projector lens, and the first stage is operated to the left and right toward the projector lens. A second stage and a third stage that moves the second stage back and forth along the direction of the light projecting lens are provided.

  In the edge detection device according to the present invention, the predetermined range is within 0.01 ° centering on the optical axis, and the range in which the light receiving cells used for the measurement of the line sensor by the monochromatic light beam converged in the predetermined range is arranged Is irradiated.

  The light beam adjustment method for an edge detection device according to the present invention is the light beam adjustment method for the edge detection device described above, wherein the step of disposing the projector and the light receiver facing each other and the light projector side of the measurement space formed between the light projector and the light receiver are provided. Measuring a dimension of the measurement object by arranging a measurement object having a predetermined dimension and measuring the dimension of the measurement object; and measuring a dimension of the measurement object by arranging a measurement object having the predetermined dimension on the light receiver side of the measurement space. And a monochromatic light beam projected from the light projecting lens to the line sensor by adjusting the position of at least one of the light source and the light projecting lens based on the dimensional difference between the step and the measurement object measured in both steps. Adjusting the degree of convergence of.

  The light beam adjustment method of the edge detection device according to the present invention is the light beam adjustment method of the edge detection device described above, wherein the light projector and the light receiver are arranged to face each other at different intervals, and the line sensor receives the monochromatic light beam from the light projector at each interval. The step of measuring the cell distribution and adjusting the position of at least one of the light source and the light projecting lens based on the light receiving cell distribution measured at each interval, the light is projected from the light projecting lens to the line sensor. Adjusting the degree of convergence of the monochromatic light beam.

According to the present invention, a light receiver having a line sensor in which a plurality of light receiving cells are arranged, a light source that generates monochromatic light, and monochromatic light from the light source is converged in a predetermined range from parallel to the optical axis. The Fresnel diffraction that occurs at the edge of the measurement object that occurs when the measurement object blocks a part of the monochromatic light beam in the measurement space. Analyzing the received light pattern, it has an edge detection unit that detects the edge position of the measurement object, so it is formed between the projector and the light receiver without generating perfect parallel light that is difficult to adjust There is an effect that it is possible to prevent the measurement range from being narrowed due to the position of the measurement object in the measurement space. Note that “original” here means that a moving amount of 30 mm can be measured in the case of the measurement object 104b in FIG. 8A, for example, and “the measurement range is narrowed” means, for example, FIG. In a), the measurement object 104a moves 30 mm, but only 28 mm can be measured.

  According to the present invention, the projector includes the first stage on which the light source is mounted so that the monochromatic light emitting portion of the light source faces the projector lens, and the second stage that moves the first stage to the left and right toward the projector lens. And the third stage that moves the second stage back and forth along the direction of the light projecting lens, it is possible to adjust the monochromatic light beam emitted from the light projector to the light receiver with a simple configuration.

  According to the present invention, the predetermined range is within 0.01 ° about the optical axis, and the monochromatic light beam converged within the predetermined range is irradiated to the range where the light receiving cells used for the measurement of the line sensor are arranged. Therefore, there is an effect that the error between the actual movement amount of the measurement object and the measurement value can be suppressed to the μm order.

  According to the present invention, the step of disposing the projector and the light receiver opposite to each other, the measurement object having a predetermined dimension on the light projector side of the measurement space formed between the light projector and the light receiver, and the dimensions of the measurement object Based on the dimensional difference of the measurement object measured in both steps, the step of measuring the measurement object, the step of placing the measurement object having a predetermined dimension on the light receiver side of the measurement space and measuring the dimension of the measurement object And adjusting the degree of convergence of the monochromatic light beam projected from the light projecting lens to the line sensor by adjusting the position of at least one of the light source and the light projecting lens. There is an effect that the degree of convergence of the luminous flux can be maintained.

  According to the present invention, the step of measuring the light receiving cell distribution of the line sensor that receives the monochromatic light beam from the light projector at each interval by disposing the projector and the light receiver at different intervals, and the light receiving cell distribution measured at each interval. And adjusting the degree of convergence of the monochromatic light beam projected from the light projecting lens to the line sensor by adjusting the position of at least one of the light source and the light projecting lens. Thus, the degree of convergence of the monochromatic light beam can be maintained.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of an edge detection apparatus according to Embodiment 1 of the present invention. In FIG. 1, the edge detection apparatus according to Embodiment 1 includes a projector 1, a light receiver 2, and an edge detector 3. The light projector 1 is arranged to face the light receiving surface of the line sensor 8 of the light receiver 2 and includes a light source 6 and a light projecting lens 7 made of a laser diode (LD). The light source 6 is provided on a moving stage (not shown), and at least the distance A to the light projecting lens 7 in FIG. 1 can be adjusted. By adjusting this distance A, the projection lens 7 converges the monochromatic light generated by the light source 6 within a predetermined range from parallel to the optical axis while aligning the optical axis with the center of the line sensor 8. It is output as a monochromatic light beam that has been (squeezed).

  The light receiver 2 includes a line sensor 8 and an A / D converter 9. The line sensor 8 has a light receiving surface in which a plurality of light receiving cells (pixels) are arranged at a predetermined pitch in a certain direction, and receives the monochromatic light beam emitted from the projector 1. The A / D converter 9 converts the analog output signal from the line sensor 8 into a digital signal and outputs the digital signal to the edge detector 3.

  The edge detection unit 3 includes a microcomputer and includes a processor 10 and a display unit 11. The processor 10 analyzes the output of the line sensor 8 digitally converted by the A / D converter 9 and determines the edge position in the arrangement direction of the light receiving cells of the measurement object 5 that shields a part of the monochromatic light beam in the measurement space 4. To detect. The display unit 11 displays the detection result by the processor 10. The edge detector 3 may be provided in the light receiver 2.

  In the projector 1, the monochromatic light generated by the light source 6 is converted into a monochromatic light beam converged in a predetermined range from parallel to the optical axis by the light projecting lens 7, and then irradiated to the line sensor 8. In the measurement space 4 between the projector 1 and the line sensor 8, when the measurement object 5 moves so as to cross the optical path of the monochromatic light beam emitted from the projector 1, one of the monochromatic light beams to be received by the line sensor 8. Part is shielded. In addition, by setting the width La of the light projecting lens 7 to be larger than the width Lb of the line sensor 8, it is possible to perform measurement using all the light receiving cells of the line sensor 8, and match the optical axis or the measurable range. Easy to operate. Further, if the width La of the light projecting lens 7 is set larger than the width Lb of the line sensor 8, the light receiving cells of the line sensor 8 can be measured by the light receiving cells near the center without using the light receiving cells at both ends. Similarly, the optical axis or the measurable range can be easily adjusted.

  The processor 10 of the edge detection unit 3 changes the total received light amount of the line sensor 8 caused by the measurement object 5 blocking a part of the monochromatic light beam in the measurement space 4 or the Fresnel diffraction generated at the edge portion of the measurement object 5. The edge position of the measurement object is detected by analyzing the light reception pattern resulting from the above. Measurement results such as the edge position of the measurement object 5 detected in this way can also be displayed on the display unit 11 so that the user can visually recognize the measurement results.

  FIG. 2 is a diagram showing a monochromatic light beam irradiated to the line sensor via the light projecting lens in FIG. 2, in the edge detection apparatus according to the first embodiment, the distance A from the monochromatic light emission surface of the light source 6 to the position of the projection lens 7 is adjusted by moving the moving stage of the light source 6. The generated monochromatic light is converted into a monochromatic light beam converged in a predetermined range from parallel to the optical axis.

  As shown in FIG. 2, by narrowing the monochromatic light beam by the light projecting lens 7, the distance B from the light receiving surface of the line sensor 8 to the edge is large, and the measurement object 5a moves on the light projecting lens 7 side in the measurement space 4. However, it blocks the monochromatic light to be received by the light receiving cell 8a at the end of the line sensor 8 at the same position as the measurement object on the line sensor 8 side.

  Thus, unlike the conventional edge detection device, the edge detection device according to the first embodiment squeezes the monochromatic light beam with the light projecting lens 7 and irradiates the line sensor 8 with the measurement object in the measurement space 4. The actual movement amount of the measurement object 5 can be reliably detected regardless of the position of the measurement object 5, and the measurement impossible state caused by the position and distance of the measurement object 5 in the measurement space 4 from the line sensor 8 or the projection lens 7 Can be suppressed. Further, by adjusting only the direction in which the monochromatic light beam is converged at the time of manufacture, the same characteristics and performance can be derived for all products, and product management becomes easy.

  The predetermined range for converging the monochromatic light beam is as follows. The distance from the end surface position a of the light projecting lens 7 to the position b of the light receiving surface of the line sensor 8 is 300 mm with respect to the optical axis of the monochromatic light beam. It is desirable that the range is not more than 01 °. Furthermore, it is desirable to irradiate the monochromatic light beam beyond the array width of the cells actually used for measurement among the light receiving cells of the line sensor 8 even when the distance between the measuring space 4 of the projector 1 and the light receiver 2 is increased.

  In an actual edge detection device, high accuracy of measurement is required, and the actual movement amount of the measurement object 5 as shown in FIG. 9 (the movement amount of the moving stage that moves the measurement object in the measurement space 4). ) And the measured value of the amount of movement of the edge position of the measurement object 5 must be at least in the order of μm (about several tens of μm). The above-described preferred range for converging the luminous flux defines a critical condition where the error is within the allowable range.

  If the luminous flux is further narrower than the above range, a measurement value smaller than the actual movement amount of the measurement object 5 can be obtained. For example, if the monochromatic light beam is too narrow outside a predetermined range, the error between the actual movement amount of the measurement object 5 and the measurement value described above is shifted from about 100 μm to about several hundred μm.

  Further, in the above-described preferable range for converging the light beam, the difference from the actual movement amount becomes large when the monochromatic light beam is excessively narrowed and the line sensor 8 and the measurement object 5 are separated (when the distance B is large). Can be prevented. Further, by converging the light beam in the above preferable range, the difference in size between the width La of the light projecting lens 7 and the width Lb of the line sensor 8 can be minimized. That is, it is not necessary to make the light projection lens 7 larger than necessary with respect to the measurement width to be actually measured.

  In the case where the light beam is not converged as in the conventional case, as described above, an unmeasurable area occurs in 1 mm before the measurement is started and 1 mm in the back until the measurement space is passed. It becomes impossible to measure the moved area. On the other hand, if the line sensor 8 can acquire data corresponding to the moving amount of 30 mm of the measurement object 5 by converging the luminous flux within the preferable range, the data is corrected and converted into an actual moving amount. It is easy.

Next, a specific configuration of the projector 1 will be described.
FIG. 3 is a diagram showing the internal configuration of the projector in FIG. 1, and shows the internal structure of the projector 1 with the upper cover removed from the top. In FIG. 3, description is omitted or simplified except for the characteristic part in the present invention.

  In the position adjusting stage 12, the plate-like member 16a provided with a slot whose longitudinal direction is perpendicular to the paper surface of FIG. 3 and the plate-like member 16b to which the light source 6 is attached sandwich the light source 6 back and forth. The light source 6 is held by screwing the fixing screw 15, which is disposed in the long hole of the plate-like member 16 a, into the screw hole of the plate-like member 16 b. In this position adjusting stage 12, the fixing screw 15 is loosened and moved along the longitudinal direction of the elongated hole, and then screwed again, so that the light source 6 is oriented in the direction perpendicular to the plane of FIG. Can be adjusted.

  Further, the position adjusting stage 13 is provided with the position adjusting stage 12 and is formed of a plate-like member having a long hole 17 whose longitudinal direction is along the A1 direction in FIG. And is screwed into the screw hole of the position adjusting stage 14. The position adjusting stage 13 adjusts the position of the light source 6 in the A1 direction by loosening the fixing screw 18 and moving the plate member along the longitudinal direction of the elongated hole 17 and then screwing it again. Can do.

  The position adjusting stage 14 is provided with a position adjusting stage 13 and is formed of a plate-like member having a long hole 19 whose longitudinal direction is along the A2 direction in FIG. 3. The fixing screw 20 is passed through the long hole 19. It is installed by screwing into a screw hole provided in the housing of the projector 1. The position adjusting stage 14 adjusts the position of the light source 6 in the A2 direction by loosening the fixing screw 20 and moving the plate member along the longitudinal direction of the long hole 19 and then screwing it again. Can do.

  The light projecting lens 7 is inserted into the lens holder 21a and fixed by a fastener 21b. The end surface perpendicular to the A2 direction of the lens holder 21a is open, and monochromatic light is input from the opening on the light source 6 side, and a monochromatic light beam is output from the opening on the end surface facing this.

  As described above, in the projector 1 according to the first embodiment, the optical axis of the monochromatic light beam is aligned with the center of the line sensor 8 by the position adjustment stages 12 and 13, and the light source 6 and the light projection lens are used by using the position adjustment stage 14. The monochromatic light flux from the light source 6 is converged within a predetermined range from parallel to the optical axis by adjusting the light source 6 and the light projecting lens 7 to be far away from each other. Output as a monochromatic light beam.

  In FIG. 3, the configuration in which the position of the light source 6 is adjusted using the position adjustment stage 14 is shown. However, the light projection lens 7 is arranged on the position adjustment stage, and the light projection lens 7 side is in the A2 direction. You may comprise so that it may be moved along and the width | variety of a monochromatic light beam may be adjusted.

Next, the actual measurement width of the line sensor will be described.
FIG. 4 is a diagram showing the line sensor output of the edge detection apparatus according to the first embodiment, and shows the light receiving cell distribution of the line sensor 8 that receives the irradiation light from the projector 1. Note that the horizontal axis in FIG. 4 indicates the light receiving cell number corresponding to the light receiving cell position of the line sensor 8, and the vertical axis indicates the actual light quantity that is the intensity of the received monochromatic light. Here, the light receiving cell number is a serial number assigned in order from the light receiving cell (light receiving cell 8a in FIG. 2) to the light receiving cell arranged in the line sensor 8 in order. The actual light quantity is a count value of the output signal of the line sensor 8 converted into a digital signal by the A / D converter 9 of the light receiver 2.

  In FIG. 4, the light receiving cells of the line sensor 8 included in the light receiving cell number range 2a indicate light receiving cells that actually receive irradiation light from the light projecting lens 7, and the lines included in the light receiving cell number range 2b. The light receiving cell of the sensor 8 is a light receiving cell used for edge detection of the measurement object 5. In addition, the light receiving cells of the line sensor 8 included in the light receiving cell number range 2 a are light receiving cells in which the irradiation light from the light projecting lens 7 is shielded by the measurement object 5.

  As described above, among the light receiving cells included in the light receiving cell number range 2a that actually receives the monochromatic light beam, in the light receiving cell at the end of the line sensor 8, the received light quantity decreases sharply. Depending on the positional relationship between the light source 6, the light projecting lens 7, and the line sensor 8, the light receiving cells near the minimum value or the maximum value of the cell numbers may hardly receive monochromatic light.

  Therefore, in the first embodiment, the monochromatic light beam from the light source 6 whose optical axis is aligned with the central portion of the line sensor 8 is changed to a monochromatic light beam converged in a predetermined range from a state parallel to the optical axis, and light reception is performed. Among the light receiving cells included in the cell number range 2a, the light receiving cell array width defined by the light receiving cells in the light receiving cell number range 2b located near the center of the line sensor 8 is defined as an actual measurement width. The light receiving cell array width can be accurately obtained from the light receiving cell number in the light receiving cell number range 2b, and the total actual movement amount of the edge of the measuring object 5 is measured within the range of the actual measurement width. It is possible.

  As described above, according to the first embodiment, the monochromatic light beam from the projector 1 whose optical axis is aligned with the center of the line sensor 8 is converged (narrowed) in a predetermined range from parallel to the optical axis. In addition, since the light is projected onto the line sensor 8 as a monochromatic light beam, the measurement error due to the position of the measurement object 5 in the measurement space 4 is eliminated without generating complete monochromatic parallel light that is difficult to adjust, and the measurement object The actual movement amount of the edge position of the object 5 can be reliably measured.

Embodiment 2. FIG.
In the second embodiment, in the measurement space 4 formed between the projector 1 and the light receiver 2, the measurement objects 5 having predetermined dimensions are alternately arranged in the vicinity of the projector 1 and in the vicinity of the light receiver 2. In each case, the dimension of the measurement object 5 (the dimension of the array width of the light receiving cells that cannot receive monochromatic light) is measured, and the degree of convergence of the monochromatic light beam is adjusted based on the measurement dimension difference of these measurement objects 5 To do.

  Here, the degree of convergence of the monochromatic light beam is a degree indicating how much the monochromatic light from the projector 1 whose optical axis is aligned with the center of the line sensor 8 is converged from parallel to the optical axis. . Therefore, if the monochromatic light beam emitted from the projector 1 is completely parallel light, the value of the difference is 0 even if the distance of the measurement object 5 from the light receiving surface of the line sensor 8 is different.

  FIG. 5 is a diagram for explaining a light beam adjustment method of the edge detection apparatus according to the second embodiment of the present invention, and shows the positional relationship of the measuring object 5 with respect to the projector 1 and the light receiver 2. In FIG. 5, the distance from the light receiving surface of the line sensor 8 is B1, and the measurement dimension of the measurement object 5 disposed in the vicinity of the projector 1 and the distance from the light receiving surface of the line sensor 8 are B2 (B1> B2). The degree of convergence of the monochromatic light beam is adjusted based on the difference from the measurement dimension of the measurement object 5 disposed in the vicinity of the light receiver 2.

  First, the projector 1 and the light receiver 2 are arranged to face each other. For example, as shown in FIG. 2 of the first embodiment, the projector 1 and the receiver 2 are located at a position where the distance from the end surface position a of the light projecting lens 7 to the position b of the light receiving surface of the line sensor 8 is 300 mm. Place.

  Thereafter, the measurement object 5 having a predetermined dimension is arranged on the light projector 1 side of the measurement space 4 formed between the light projector 1 and the light receiver 2, and the dimension of the measurement object 5 is measured. In the example of FIG. 5, the dimension of the measuring object 5 arranged at the position a is measured. Subsequently, the measurement object 5 having a predetermined dimension is arranged on the light receiver 2 side of the measurement space 4 and the dimension of the measurement object 5 is measured. In the example of FIG. 5, the dimension of the measuring object 5 arranged at the position b is measured.

  Next, by adjusting at least one position of the light source 6 and the light projecting lens 7 based on the dimensional difference between the measurement object 5 measured at the position a and the position b, the line sensor is moved from the light projecting lens 7 to the line sensor. 8 adjusts the degree of convergence of the monochromatic light beam projected onto the light beam 8. Here, from the difference between the measurement dimension of the measurement object 5 arranged at the position a and the measurement dimension of the measurement object 5 arranged at the position b, the monochromatic light beam that has passed through the projection lens 7 is 0 with respect to the optical axis. It is adjusted to converge within the range of .01 ° or less.

  As a method for adjusting the optical system, when the projector 1 is configured as shown in FIG. 3, the position of the light source 6 is adjusted using the position adjustment stages 12, 13, and 14. In addition, the position of the light projecting lens 7 may be moved and adjusted, or the position of the line sensor 8 of the light receiver 2 may be moved and adjusted.

  As described above, according to the second embodiment, since the degree of convergence of the monochromatic light beam is adjusted using the measurement dimension of the measurement object 5 detected by the light receiver 2, the degree of convergence of the monochromatic light beam is simply determined based on the standard. Can be maintained.

Embodiment 3 FIG.
In the second embodiment, the difference in measurement dimension of the measurement object 5 for each distance of the measurement object 5 from the light receiving surface of the line sensor 8 is used as a reference. However, in the third embodiment, the light projector 1 and the light reception are used. The distance from the device 2 is changed, and the degree of convergence of the monochromatic light beam is adjusted with reference to the light receiving cell distribution obtained from the output of the line sensor 8 at that time.

  FIG. 6 is a diagram for explaining a light beam adjustment method of the edge detection apparatus according to the third embodiment of the present invention, and shows the light receiving cell distribution of the line sensor 8 that receives the irradiation light from the projector 1. In FIG. 6, the horizontal axis indicates the light receiving cell number corresponding to the light receiving cell position of the line sensor 8 as in FIG. 4, and the vertical axis indicates the actual light quantity that is the intensity of the received monochromatic light.

  First, the light projector 1 and the light receiver 2 are arranged to face each other at different intervals, and the light receiving cell distribution of the line sensor 8 that receives the monochromatic light beam from the light projector 1 at each interval is measured. Here, the width of the light receiving cell distribution corresponds to the array width of the light receiving cells that receive a predetermined amount of light among the light receiving cells arranged in a certain direction of the line sensor 8, and is a single color irradiated on the light receiving surface of the line sensor 8. Corresponds to the width of the luminous flux. In the example of FIG. 6, the light receiving cell distribution by the light receiving cells of 100 counts or more, which is a light amount that can be actually used for measurement, is measured.

  The projector 1 and the light receiver 2 are arranged to face each other so that the optical axis of the monochromatic light beam emitted from the projector 1 is located at the center of the line sensor 8, for example, the projector 1 and the light receiver 2 are arranged at an interval of 0 mm, A light receiving cell distribution with an actual light quantity of 100 counts or more is measured. Subsequently, the distance between the projector 1 and the light receiver 2 is separated by 300 mm, and the distribution of light receiving cells whose actual light quantity is 100 counts or more is measured.

  Next, a single color projected from the light projecting lens 7 to the line sensor 8 by adjusting the position of at least one of the light source 6 and the light projecting lens 7 based on the light receiving cell distribution measured at each interval. Adjust the degree of convergence of the luminous flux. For example, the optical system is adjusted so that the light receiving cell distribution width when the distance between the projector 1 and the light receiver 2 is 300 mm is narrower than the light receiving cell distribution width when the distance is 0 mm.

  As the predetermined specified value, similarly to the first embodiment, when the distance between the light projector 1 and the light receiver 2 is 0 mm and 300 mm, the light passes through the light projecting lens 7 due to the difference in monochromatic light beam width at 300 mm. The width difference of the light receiving cell distribution is set so that the monochromatic light beam converges within a range of 0.01 ° or less with respect to the optical axis.

  Further, as a method for adjusting the optical system, when the projector 1 is configured as shown in FIG. 3, the position of the light source 6 is adjusted by the position adjustment stages 12, 13, 14 or the light projecting lens 7. The position may be moved for adjustment.

  As described above, according to the third embodiment, since the degree of convergence of the monochromatic light beam is adjusted based on the light receiving cell distribution obtained from the output of the line sensor 8, the degree of convergence of the monochromatic light beam can be easily maintained based on the standard. Is possible.

It is a figure which shows the structure of the edge detection apparatus by Embodiment 1 of this invention. It is a figure which shows the monochromatic light beam irradiated to a line sensor via the light projection lens in FIG. It is a figure which shows the internal structure of the light projector in FIG. It is a figure which shows the line sensor output of the edge detection apparatus by Embodiment 1. FIG. It is a figure for demonstrating the light beam adjustment method of the edge detection apparatus by Embodiment 2 of this invention. It is a figure for demonstrating the light beam adjustment method of the edge detection apparatus by Embodiment 3 of this invention. It is a figure which shows the structure of the conventional edge detection apparatus. It is a figure which shows the case where a monochromatic light beam is expanded from the width | variety of the light receiving cell arrangement | positioning direction of a line sensor. It is a graph which shows the movement amount measurement result of the edge position with respect to the movement amount of the measuring object by the edge detection apparatus in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light projector 2 Light receiver 3 Edge detection part 4 Measurement space 5, 5a Measurement object 6 Light source 7 Light projection lens 8 Line sensor 8a Light reception cell 9 A / D conversion part 10 Processor 11 Display part 12-14 Position adjustment stage 15,18 , 20 Fixing screws 16a, 16b Plate-like members 17, 19 Slot 21a Lens holder 21b Fastener 100 Line sensor 101 Projector 101a Light source 101b Optical fiber 101c Projector lens 102 Edge detector 103 Measurement space 104, 104a, 104b Measurement object Object 105 Light receiving cell

Claims (5)

A light receiver having a line sensor in which a plurality of light receiving cells are arranged;
A projector having a light source that generates monochromatic light, and a light projecting lens that converts the monochromatic light from the light source into a monochromatic light beam converged in a predetermined range from parallel to the optical axis, and projects the light onto the line sensor; ,
Edge that detects the edge position of the measurement object by analyzing the light receiving pattern caused by Fresnel diffraction generated at the edge portion of the measurement object caused by the measurement object blocking a part of the monochromatic light beam in the measurement space edge detecting apparatus having a <br/> a detection unit.   The projector includes a first stage on which the light source is mounted so that a monochromatic light emitting portion of the light source faces the projector lens, a second stage that moves the first stage to the left and right toward the projector lens, The edge detection apparatus according to claim 1, further comprising a third stage that moves the second stage back and forth along the direction of the light projecting lens. The predetermined range is within 0.01 ° about the optical axis,
3. The edge detection apparatus according to claim 1, wherein the monochromatic light beam converged in the predetermined range is irradiated to a range in which light receiving cells used for measurement of a line sensor are arranged. The light beam adjustment method for an edge detection device according to claim 1,
A step of disposing the projector and the receiver opposite to each other;
Placing a measurement object having a predetermined dimension on the light projector side of a measurement space formed between the projector and the light receiver, and measuring the dimension of the measurement object;
Disposing the measurement object having the predetermined dimension on the light receiver side of the measurement space and measuring the dimension of the measurement object;
A monochromatic light beam projected from the light projecting lens to the line sensor by adjusting the position of at least one of the light source and the light projecting lens based on the dimensional difference between the measurement objects measured in both steps. Adjusting the degree of convergence of the edge detecting device. The light beam adjustment method for an edge detection device according to claim 1,
Measuring the light receiving cell distribution of the line sensor that receives the monochromatic light beam from the light projector at each interval, with the projector and the light receiver facing each other at different intervals;
The degree of convergence of the monochromatic light beam projected from the light projecting lens to the line sensor by adjusting the position of at least one of the light source and the light projecting lens based on the light receiving cell distribution measured at each interval. Adjusting the luminous flux of the edge detecting device.

Images