JP2019060649A - Measuring device and measurement method - Google Patents

Abstract

To provide a measuring device and a measurement method which, by a simple configuration, measure surface reflection and internal reflection separately from each other.SOLUTION: A measuring device comprises: a light emission unit for emitting irradiation light; a first lens for changing divergence of the irradiation light; a diaphragm unit for narrowing down the irradiation light; a second lens for condensing light so that the irradiation light is irradiated from a predetermined direction of an object; a light-receiving unit, arranged between the diaphragm and the second lens, for receiving reflected light of the irradiation light that is reflected by the object after being radiated thereto and outputting a received light quantity distribution relative to a reflection angle; and an arithmetic unit for controlling the light-receiving unit so that a plurality of pieces of irradiation light are emitted, controlling the light-receiving unit so as to receive the reflected light of the plurality of pieces of irradiation light that are reflected by the object after being radiated thereto and output a plurality of received light quantity distributions, and computing an approximate curve that indicates a distribution of the minimum value of a received light quantity width relative to an angle of reflection for each reflection angle calculated from a synthetic received light quantity distribution synthesized from the plurality of received light quantity distributions.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a measuring device and a measuring method.

  In Patent Document 1, a reference member having a gray reference density, a reading unit, an output unit that outputs a correction time line signal having a cycle longer than a reading time line signal and a reading time line signal, and a conversion unit A correction unit and a control unit, and when the control unit outputs the line signal at the time of correction from the output unit, the correction unit acquires the correction data by reading the reference member for each line based on the line signal at the time of correction Gradation value is acquired by performing data acquisition processing and shading correction of digital data acquired by reading an original for each line based on the line signal at the time of outputting the line signal at the time of reading based on the correction data. An image reading apparatus is disclosed which performs a reading process. The image reading apparatus disclosed in Patent Document 1 uses the minimum value of white data, but the minimum value is the minimum value of the reading value of the reference plate.

  In Patent Document 2, a first acquisition unit for acquiring a first reflectance obtained by irradiating a measurement target from a first direction and measuring diffused light, and closer to the horizon than the first direction A second acquisition unit for acquiring a second reflectance obtained by irradiating the measurement target from a second direction, which is a direction, and measuring the diffused light; and the acquired first reflectance and second reflection And determining means for determining whether the object to be measured is an object affected by internal scattering based on the ratio and output means for outputting the reflection characteristic of the object to be measured based on the determination result by the determining means. A measuring device is disclosed. In the measuring device disclosed in Patent Document 2, the illumination unit and the light receiving unit are moved to measure the influence of internal scattering in the object to be measured.

  In Patent Document 3, a reading unit that reads image data of an image data reading unit, an illumination unit that illuminates the image data reading unit, a density reference plate provided in the image data reading unit, and a density reference plate are illuminated by the illumination unit. The reflected light of the density reference plate is read by the reading means, the offset holding means holds the value as an offset, and the reflected light of the density reference plate is read by the reading means when the density reference plate is not illuminated by the illumination means Means for holding the black reference value as a black reference value, reading light reflected by the density reference board when the density reference board is illuminated by the illumination means, and holding the white reference value for holding the value as a white reference value Means, and an original document located in the image data reading unit is illuminated by the illumination unit and read by the reading unit, and an offset holder for the image data of the obtained document is obtained. The document read by the reading means by applying a predetermined equation using the offset held in the black reference value held in the black reference value holding means and the white reference value held in the white reference value holding means A shading correction apparatus is disclosed, comprising: correction means for correcting image data of the image. In the shading correction device disclosed in Patent Document 3, the correction is performed using the minimum value of the average value of the data of the predetermined line read by the reading unit.

JP, 2016-163101, A Unexamined-Japanese-Patent No. 2017-020816 Japanese Patent Application Laid-Open No. 07-212587

  An object of the present invention is to provide a measuring device and a measuring method for measuring surface reflection and internal reflection separately by a simple configuration.

  In order to achieve the above object, the measurement apparatus according to claim 1 includes a light emitting unit including a plurality of light emitting elements and emitting light to be irradiated to an object, and a divergence of the irradiation light emitted from the light emitting unit A first lens that changes the degree, a diaphragm unit that narrows the irradiation light emitted from the first lens, and the irradiation light that has passed through the diaphragm unit from a predetermined direction of the object And a plurality of light receiving elements, and are disposed between the diaphragm and the second lens, and the light reflected from the object is reflected by the irradiation light. A light receiving unit that receives light by a plurality of light receiving elements and outputs a received light amount distribution with respect to a reflection angle, and controls the light emitting unit to emit at least a part of the plurality of light emitting elements to emit a plurality of irradiation lights; Multiple radiations The light receiving unit is controlled to receive the reflected light emitted from the object and reflected and to output a plurality of received light amount distributions, and the reflection angle calculated from the combined received light amount distribution obtained by combining the plurality of received light amount distributions And an operation unit for calculating an approximate curve indicating a distribution of the minimum value of the light reception light amount width for each of the light reception angle and the reflection angle.

  In the second aspect of the present invention, in the first aspect of the present invention, the calculation unit extracts the amount of received light in a predetermined range for each width of the received light amount, and The approximate curve is calculated using the amount of light received.

  In the third aspect of the present invention, in the second aspect of the present invention, the calculation unit extracts the minimum value of the received light amount for each of the received light amount widths, and uses the minimum value to calculate the approximate curve. It is an operation.

  The invention according to a fourth aspect is the invention according to the third aspect, wherein the calculation unit calculates the approximate curve by connecting the minimum values.

  The invention according to claim 5 is the invention according to claim 3, wherein the calculation unit calculates the approximate curve by polynomial approximation of the minimum value.

  In the invention according to a sixth aspect, in the invention according to the second aspect, the calculation unit extracts the light reception light amount in a predetermined range from the minimum value for each light reception light amount width, and determines the predetermined light amount. The approximate curve is calculated using the received light amount in the specified range.

  Also, in the invention according to claim 7, in the invention according to claim 6, the calculation unit connects the average value of the minimum value and the maximum value of the received light amount in the predetermined range, and the approximate curve is obtained. Is calculated.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the predetermined direction is a direction parallel to the optical axis of the second lens. It is a thing.

  The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the predetermined direction is a direction parallel to the optical axis of the second lens. Of the plurality of predetermined angles, and the operation unit calculates the approximate curve for each of the plurality of directions, and reflects the minimum value of the combined approximate curve in which the plurality of approximate curves are combined. The distribution for the angle is further calculated.

  The invention according to claim 10 further includes, in the invention according to claim 9, setting means for setting the irradiation direction of the irradiation light, and the calculation unit is configured to emit the irradiation light in the plurality of directions. The distribution with respect to the reflection angle of the minimum value of the combined approximate curve is calculated while controlling the setting means so that

  The invention according to claim 11 is the light-emitting section according to the invention according to claim 10, wherein the setting means has a variable inclination angle with respect to the direction perpendicular to the object. An optical module in which the lens, the aperture unit, the second lens, and the light receiving unit are integrated.

  In the invention according to claim 12, in the invention according to claim 10, the setting means is a mounting portion of the object which can set an inclination angle of the object.

  The invention according to claim 13 is the invention according to claim 10, wherein the setting means is a position change unit for changing the position of the aperture.

  In order to achieve the above object, the measurement method according to claim 14 includes a light emitting unit including a plurality of light emitting elements and emitting light to be irradiated to an object, and a divergence of the irradiation light emitted from the light emitting unit A first lens that changes the degree, a diaphragm unit that narrows the irradiation light emitted from the first lens, and the irradiation light that has passed through the diaphragm unit from a predetermined direction of the object And a plurality of light receiving elements, and are disposed between the diaphragm and the second lens, and the light reflected from the object is reflected by the irradiation light. A measuring method using a measuring device including a plurality of light receiving elements for receiving light and outputting a received light amount distribution with respect to a reflection angle, wherein at least a part of the plurality of light emitting elements is caused to emit light by an operation unit. Emit multiple illumination lights The light emitting unit is controlled to cause the plurality of irradiation lights to be irradiated to the target object and the reflected light is reflected, and the light receiving unit is controlled to output a plurality of received light amount distributions, An approximate curve indicating the distribution of the minimum value of the light receiving light width for each of the reflection angles calculated from the combined light receiving light distribution obtained by combining the light receiving light distribution is calculated with respect to the reflection angle.

  According to the inventions of claims 1 and 14, it is possible to obtain the effect of providing a measuring device and a measuring method for measuring surface reflection and internal reflection separately with a simple configuration.

  According to the second aspect of the present invention, the calculation of the approximate curve is simplified as compared with the case where the approximate curve is calculated without using the light reception amount in a predetermined range for each light reception light amount width. An effect is obtained.

  According to the invention of claim 3, the calculation of the approximate curve is further simplified as compared with the case of calculating the approximate curve without using the minimum value of the received light amount extracted for each received light amount width. The effect is obtained.

  According to the fourth aspect of the present invention, it is possible to obtain the effect that the amount of calculation in the calculation unit can be reduced compared to the case of calculating the approximate curve by polynomial approximation.

  According to the fifth aspect of the present invention, it is possible to obtain the effect of acquiring the amount of internally reflected light closer to the actual distribution as compared with the case where the minimum value is connected to calculate the approximate curve.

  According to the invention described in claim 6, the internal reflection is more accurately performed as compared with the case where the approximate curve is calculated without using the light receiving light amount in a predetermined range from the minimum value extracted for each light receiving light amount width. The effect is obtained that the light quantity is obtained.

  According to the seventh aspect of the present invention, it is possible to obtain the effect of acquiring the amount of internally reflected light closer to the actual distribution, as compared with the case where the minimum value is connected to calculate the approximate curve.

  According to the eighth aspect of the present invention, compared with the case where the predetermined direction is the direction forming an angle with the optical axis of the second lens, the irradiation light from the direction perpendicular to the object is used. The effect is obtained that the received light amount distribution is obtained.

  According to the invention as set forth in claim 9, the effect is obtained that the amount of internally reflected light of an object including a large number of reflecting surfaces at a specific angle is obtained as compared with the case of irradiating the irradiation light from a single direction. Is obtained.

  According to the invention as set forth in claim 10, the distribution with respect to the reflection angle of the minimum value of the combined approximate curve is easily calculated, as compared with the case where the setting means for setting the irradiation direction of the irradiation light is not included. Is obtained.

  According to the invention as set forth in claim 11, as compared with the case where the setting means is configured other than the optical module in which the light emitting part, the first lens, the diaphragm part, the second lens and the light receiving part are integrated. The effect of reducing the influence of the tilt angle on the optical system is obtained.

  According to the invention as set forth in claim 12, the inclination angle is set independently of the measuring apparatus main body as compared with the case where the setting means is configured other than the mounting portion of the object which can set the inclination angle of the object. Can be obtained.

  According to the invention as set forth in claim 13, the effect is obtained that the irradiation angle can be easily set as compared with the case where the setting means is configured other than the position changing portion for changing the position of the aperture.

It is a figure which shows the structure in the case of measuring the target object of the measuring device which concerns on 1st Embodiment. It is a figure which shows reflected light in the case of measuring the target object of the measuring device which concerns on 1st Embodiment. (A) of the light receiver which concerns on 1st Embodiment is a top view which shows an example of a structure, (b) is a graph which shows an example of light quantity output distribution. It is a block diagram which shows an example of a structure of the control part which concerns on 1st Embodiment. It is a figure for demonstrating operation | movement of the measuring device which concerns on 1st Embodiment. (A) is a figure explaining reflection in a low transparency object, (b) It is a figure explaining reflection in a high transparency object. (A) is a figure explaining surface reflection and internal reflection in a highly transparent object, (b) is a figure explaining surface reflection and internal reflection in a low transparency object. (A) to (h) are graphs showing an example of received light amount distribution of reflected light from each irradiation point, (i) is a graph showing an example of combined received light amount distribution, (j) is a result of internal reflection operation processing It is a graph which shows an example. (A) is a figure explaining the light reception light amount width | variety which concerns on this Embodiment, (b) is a flowchart which shows the flow of a process of the internal reflection arithmetic processing program which concerns on 1st Embodiment. (A) to (c) is a figure which shows the several angle setting part which concerns on 2nd Embodiment, (d) is a figure which shows the definition of an irradiation angle. (A) is a figure which shows the reflective characteristic with respect to the irradiation light of 0 degrees of irradiation angles, and (b) is a figure which shows the reflective characteristic with respect to the irradiation light of 10 degrees of irradiation angles of an object with many reflective surfaces of a specific angle. (A) The figure which showed the irradiation light of several irradiation angles having entered into the target object with many reflective surfaces of a specific angle, and performing 1st internal reflection arithmetic processing, (b) is the 1st of (a) It is a figure which shows the result of having further performed 2nd internal reflection arithmetic processing with respect to the result of internal reflection arithmetic processing. It is a flowchart which shows the flow of a process of the 2nd internal reflection operation processing program which concerns on 2nd Embodiment.

First Embodiment
The measurement apparatus and measurement method according to the present embodiment will be described in detail with reference to FIGS. 1 to 9. First, with reference to FIG. 1 and FIG. 2, an example of a structure of the measuring device 10 which concerns on this Embodiment is demonstrated. FIG. 1 and FIG. 2 show the configuration when the measuring device 10 measures an object.

  As shown in FIG. 1, the measuring device 10 includes a light emitter 14, an optical system 30, a light receiver 18, and a control unit 20. The measuring apparatus 10 sequentially irradiates light from the Z-axis direction to the fine area of the object OB moving in the −X direction, and acquires the reflection angle distribution of reflected light (reflection angle dependency of light quantity distribution) for each irradiation light . Using the acquired reflection angle distribution, the distance to the object OB or the object OB with respect to the change in the shape or surface state (emboss, emboss, surface roughness, surface defect, adhesion of foreign matter, etc.) or internal state of the object OB The measurement is made without being affected by the variation of the angle of.

  More specifically, as shown in FIG. 1, the light emitter 14 is disposed above the apparatus up-down direction (Z-axis direction) with respect to the measurement area T through which the object OB moving in the -X direction passes. There is. In addition, the light emitter 14 includes a plurality of light emitting elements 12 which are mounted side by side in the Y-axis direction on the substrate 14A and whose light emitting direction is the −Z direction. In other words, the plurality of light emitting elements 12 are arranged in a direction orthogonal (intersecting) to the moving direction (−X direction) of the object OB. In FIG. 1, the light emitting element 12 disposed at one end (right end in the figure) of the substrate 14A in the Y axis direction is referred to as the light emitting element 12A, and the other end (left end in the figure) of the substrate 14A in the Y axis direction. The arranged light emitting element 12 is described as a light emitting element 12B, and the light emitting element 12 arranged at the center of the substrate 14A is described as a light emitting element 12C.

  The plurality of light emitting elements 12 according to the present embodiment are configured to emit light sequentially from light emitting element 12A to light emitting element 12B with a time difference, and the light from each light emitting element 12 is at different positions of object OB. It is irradiated sequentially. Then, while the object OB moves in the −X direction in the measurement area T, light emission of one cycle from the light emitting element 12A to the light emitting element 12B is repeated a plurality of times. 1 shows the light flux of the irradiation light IF when the light emitting element 12C emits light, and FIG. 2 shows the reflected light when the irradiation light IF emitted from the light emitting element 12C is reflected by the surface 200 of the object OB The luminous flux of RF is shown.

  The light emitting element 12 is not particularly limited, but as an example, a surface emitting laser (Vertical Cavity Surface Emitting Laser: VCSEL), a light emitting diode (Light Emitting Diode: LED) or the like is used.

  The optical system 30 includes a lens 32, a lens 34, and a stop 40 disposed between the lens 32 and the lens 34, and is configured as a so-called double telecentric lens. The optical system 30 is disposed between the light emitter 14 and the object OB, guides the irradiation light IF emitted from the light emitting element 12 to the object OB, and receives the reflected light RF reflected by the object OB. Lead to 18 That is, the light receiver 18 is configured so that the irradiation light IF from the light emitting element 12 emitted from the lens 34 is reflected by the object OB and receives at least a part of the light flux transmitted through the lens 34 again. Further, in the present embodiment, the optical axis of the lens 32 and the optical axis of the lens 34 are the common optical axis M, and this optical axis M is the center of the light emitting element 12C of the light emitter 14 and an opening described later. It passes through the center of 42.

  The lens 32 is, for example, a circular convex lens in plan view, and the diameter of the lens 32 is longer than the dimension D in the Y-axis direction from the light emitting element 12A to the light emitting element 12B. Therefore, almost all of the light emitted from each light emitting element 12 is transmitted through the lens 32, and the light transmitted through the lens 32 is changed in the degree of divergence and is collimated to be directed to the lens 34.

  The lens 34 is, for example, a circular convex lens in plan view. In the present embodiment, the diameter of the lens 34 is longer than the diameter of the lens 32. Then, the lens 34 condenses the light flux emitted from the lens 32 and transmitted through the lens 34 toward the surface 200 of the object OB. The position (focus) of the light condensing point of the lens 34 does not necessarily have to be the position of the surface 200 of the object OB. The position of the condensing point may be shifted (defocused) from the position of the surface 200, and the irradiation diameter of the irradiation light IF on the surface 200, that is, the size of the irradiation region of the object OB may be adjusted. The irradiation diameter according to the present embodiment is, for example, several tens of μmφ.

  A substantially circular opening 42 is formed in the stop 40, and the light is emitted from the light emitting element 12, passes through the lens 32, and enters the lens 34 by the opening 42. More specifically, the stop 40 is a plate whose plate surface is made parallel to the X-Y plane, and the stop 40 is a tip that is bent and tapered toward the lens 34 around the optical axis M. The part is formed. The front end portion is an opening edge 42A that constitutes the opening 42, and the circular shape formed by the opening 42 has the optical axis M as a central axis. The diameter of the opening 42 according to the present embodiment is about 1 mm as an example.

  Then, in the Z-axis direction, the distance F1 between the opening edge 42A and the lens 32 is substantially equal to the focal length f1 of the lens 32, and the distance F2 between the opening edge 42A and the lens 34 is the focal length f2 of the lens 34 It is almost equal.

  The optical system 30 according to the present embodiment configured as described above narrows the luminous flux from each light emitting element 12 sequentially emitted regardless of the position of the light emitting element 12 and is parallel to the optical axis M. The object OB is illuminated as the illumination light IF (see FIG. 5). In other words, by making each light emitting element 12 emit light and scan, the light beam which is narrowed and parallel to each other is irradiated to the object OB sequentially. Furthermore, in the measuring apparatus 10 according to the present embodiment, by arranging the object OB near the focusing point of the luminous flux of the irradiation light IF by the lens 34, the irradiation areas of the irradiation light IF in the object OB are substantially the same. It is considered as a minute area of diameter. As a result, in the measuring device 10, even if the position of the object OB moves up and down in the Z-axis direction, each irradiation light is irradiated with substantially the same irradiation diameter, so blurring of the image of the object OB is extremely reduced. Ru.

The light receiver 18 includes a plurality of light receiving elements 16, and receives the reflected light RF reflected by the object OB and transmitted through the lens 34 of the optical system 30. The light receiver 18 according to the present embodiment is disposed on the lower side in the Z-axis direction of the diaphragm 40 disposed between the lens 32 and the lens 34.
The light receiving element 16 is not particularly limited, but, for example, a photodiode (PD), a charge-coupled device (CCD) or the like is used. Since the light receiver 18 is disposed between the lens 32 and the lens 34, the light receiving element 16 is similarly disposed between the lens 32 and the lens 34.

  An example of a structure of the light receiver 18 is shown to Fig.3 (a). FIG. 3A is a plan view of the light receiver 18 as viewed in the Z-axis direction. The light receiver 18 shown in FIG. 1 represents a cross-sectional view taken along the line X-X 'in FIG. As shown in FIG. 3A, the light receiver 18 is, for example, a plurality of light receiving elements 16 (in FIG. 3A) on a substantially circular substrate 18A having a substantially circular opening 18B at the center. Sixty examples are shown) arranged in a plane (array). The measuring device 10 receives the reflected light RF with the entire plurality of light receiving elements 16 as a light receiving area RA. Although FIG. 3A exemplifies the light receiver 18 in which the plurality of light receiving elements 16 are disposed on the entire surface of the substrate 18A, the present invention is not limited to this. The light receiving element 16 may be a light receiver 18 in a form disposed on a part of the substrate 18A.

The range of the reflected light RF received by the light receiving area RA is, for example, the reflected light RF in the range of 0 ° to 40 ° centered on an axis parallel to the optical axis M. When the reflected light RF is received by the light receiving area RA, a three-dimensional distribution is formed by the amount of light received by each light receiving element 16. In the case where the reflected light RF is isotropic as in the case of reflection at the complete diffusion surface, the shape of the cross section of this three-dimensional distribution cut along a plane including the Z axis is shown in FIG. As shown, it becomes a substantially Gaussian curve.
The light receiving element numbers 1 to 6 on the horizontal axis in FIG. 3B correspond to the numbers 1 to 6 of the light receiving element 16 shown in FIG. 3A. In addition, since the reflected light RF is not received between the light receiving element 16 and the light receiving element 16 in the light receiving area RA, the actual output distribution is discrete, but this is omitted in FIG. There is.

  Furthermore, in the measuring device 10, the light receiving surface of the light receiving element 16 and the opening edge 42A are at the same position in the Z-axis direction, so the distance F2 between the light receiving surface of the light receiving element 16 and the lens 34 is the focal point of the lens 34. It has the same length as the distance f2. For this reason, even if the position of the object OB fluctuates up and down in the Z-axis direction or fluctuates left and right in the Y-axis direction, the object OB is irradiated with the irradiation light IF from different light emitting elements 12 The output distribution in the light receiving area RA is always constant as long as the irradiation position of the light source is the same.

  In other words, assuming that the object OB is a minute region having a size about the irradiation diameter, the light emitting element 12 is different when the object OB moves up and down in the Z-axis direction or left and right in the Y-axis direction. In the measuring apparatus 10 according to the present embodiment, the output distribution of the entire light receiving element 16 included in the light receiving area RA is the reflected light RF. The output distribution is always the same regardless of the occurrence position of.

  As shown in FIG. 4, the control unit 20 is configured to include a central processing unit (CPU) 100, a read only memory (ROM) 102, and a random access memory (RAM) 104. The CPU 100 integrally controls the entire measuring apparatus 10, and the ROM 102 is storage means for storing in advance a control program of the measuring apparatus 10 or an internal reflection operation processing program described later, etc. The RAM 104 is a program such as a control program Storage means used as a work area at the time of execution of The CPU 100, the ROM 102, and the RAM 104 are mutually connected by a bus BUS.

  Connected to the bus BUS are a motor 52 for driving the light emitter 14, the light receiver 18, and an angle setting unit 50 (see FIG. 10) to be described later, and each of the light emitter 14, the light receiver 18 and the motor 52 , Control of the CPU 100 via the bus BUS.

  Next, with reference to FIG. 5, an operation of the measuring device 10 in the case of measuring the reflection characteristic (for example, the degree of unevenness of the surface) of the object OB will be described. In FIGS. 5A to 5C, the luminous flux of the irradiation light IF and the irradiation light IF when the light emitting elements 12A, 12C, and 12B of the light emitter 14 sequentially emit light are reflected by the surface 200 of the object OB. The light flux of the reflected light RF guided to the light receiver 18 is shown.

  First, when the object OB moves in the −X direction and the tip of the object OB enters the measurement area T, the light emitting elements 12 sequentially emit light with a time difference, and the irradiation light IF is directed to the object OB It is irradiated sequentially. Then, until the rear end of the object OB passes through the measurement area T, light emission of one cycle from the light emitting element 12A to the light emitting element 12B is repeated. As described above, the light emission control of the light emitting element 12 is performed by the control unit 20.

  The degree of divergence of the luminous flux of the irradiation light IF emitted from each light emitting element 12 is changed by the lens 32 so as to be directed to the lens 34. The luminous flux whose degree of divergence is changed by the lens 32 is narrowed (restricted) by the stop 40. The light flux narrowed by the stop 40 is condensed by the lens 34 and is irradiated onto the object OB from the Z-axis direction (direction parallel to the optical axis M). In other words, the object OB is disposed in the vicinity of a condensing point by the lens 34 of the irradiation light IF. As described above, the irradiation light IF according to the present embodiment is condensed to, for example, about several tens of μmφ on the surface 200 of the object OB.

  The irradiation light IF irradiated to the object OB is reflected by the surface 200 of the object OB to generate a reflected light RF (indicated by a dotted arrow in FIG. 5). The light flux of the reflected light RF is redirected by the lens 34 so as to be directed to each light receiving element 16. The reflected light RF transmitted through the lens 34 is received by each light receiving element 16.

  According to the state of the surface 200 of the object OB, the irradiation light IF is reflected in various directions, but in the present embodiment, as described above, light passes through the incident point of the irradiation light to the surface 200 of IF. The reflected light RF is received in the range of an angle of 0 ° to 40 ° around an axis parallel to the axis M. Therefore, the light receiving area RA of the light receiver 18 corresponding to the irradiation light IF emitted from one light emitting element 12 is substantially circular. The light receiving area RA in FIG. 3A shows an example thereof.

  The light reception signal received by each light receiving element 16 is read at a predetermined timing by the control of the control unit 20. The read light reception signal may be temporarily stored in storage means such as the RAM 104 or the like. The control unit 20 generates an output distribution (light reception profile) in the light reception area RA using the light reception signal (luminance signal) corresponding to each light emitting element 12. Since the output distribution includes angle information of the reflected light RF, for example, the degree of unevenness of the object OB is measured.

  By the way, the reflected light obtained by irradiating the object with the irradiation light generally includes, in addition to the reflected light reflected on the surface, the reflected light reflected inside the object. Hereinafter, reflection on the surface of the object is "surface reflection", light reflected on the surface of the object is "surface reflection light", reflection on the inside of the object is "internal reflection", and light reflected on the inside of the object is "internal It is called "reflected light". The ratio of surface reflection to internal reflection is an object of low transparency such as metal or black resin (hereinafter referred to as “low transparency object”) and an object of high transparency such as translucent resin (hereinafter It differs from "high transparency object").

  The internal reflection will be described in more detail with reference to FIG. FIG. 6 (a) shows the reflection on a low transparency object, and FIG. 6 (b) shows the reflection on a high transparency object. In FIG. 6, the "object" is described as "sample".

  As shown in FIG. 6A, when the low transparency target is irradiated with the irradiation light, most of the irradiation light is reflected, and the reflection light is mainly surface reflection light. On the other hand, as shown in FIG. 6 (b), when the highly transparent object is irradiated with the irradiation light, in addition to the light reflected on the surface, there is light which penetrates the inside of the sample. The light that has penetrated into the inside of the sample is reflected, scattered, refracted, absorbed in the inside of the sample, and part of it is transmitted to become transmitted light. Of the transmitted light, light emitted in the incident direction of the irradiation light is internally reflected light.

  If surface reflection and internal reflection of a substance that is translucent to light of a specific wavelength are measured separately, for example, it becomes easy to distinguish the surface contamination from the deterioration of the material itself in the inspection of the article. Excellent effects such as easy identification of the cause can be expected. Conventionally, a measuring device, a measuring method, etc. which distinguish and measure surface reflection and internal reflection are also known. However, the conventional means requires much time and effort, and the measured internal reflection is also analogical.

  Therefore, in the present invention, in the measurement apparatus using the telecentric optical system, the internal reflection is calculated from the value corresponding to the minimum value or the minimum value for each reflection angle of the plurality of received light amount distributions for the plurality of irradiation lights. This provides a measuring device and a measuring method for measuring surface reflection and internal reflection separately with a simple configuration. Note that the reflection angle according to the present embodiment is defined as an angle measured from the optical axis M (see FIG. 10 (d). In FIG. 10 (d), the irradiation light IF is reflected by the reflection light RF and the irradiation angle φ is reflected). Defined in place of the angle θ).

  Here, in the present embodiment, attention is paid to the difference in reflection mode between surface reflection and internal reflection. That is, since surface reflection is reflected at an angle dependent on the shape of the surface of the object OB, the reflection characteristic varies depending on the location of the object OB. On the other hand, internal reflection hardly depends on the shape of the surface of the object OB, and it is considered that the reflection characteristic depends on the material of the object OB. Therefore, as shown in FIG. 5, the value corresponding to the minimum value or the minimum value of the light reception quantity for each reflection angle of the plurality of light reception quantity distributions acquired by irradiating the irradiation light to various irradiation points on the object OB is It is considered to reflect internal reflection that is always present depending on the material of the object OB, not the shape. That is, for example, in a combined received light amount distribution obtained by superposing received light amount distributions from different irradiation points of several tens to several hundreds, a value corresponding to the minimum value or the minimum value existing at approximately the same value at any reflection angle It is considered to indicate the magnitude of internal reflection.

  The measurement principle of internal reflection in the measuring device 10 according to the present embodiment will be described with reference to FIG. FIG. 7 (a) shows the reflection mode of the highly transparent object and the reflection angle of the received light amount (in FIG. 7 (a), it is written as “output”. The same applies hereinafter.) Shows the distribution of received light quantity. As shown in FIG. 7 (a) <1>, when the distribution of received light, which is a measurement value of the reflected light in which the surface reflection and the internal reflection are mixed, is measured, “total reflection” is shown in FIG. 7 (a) <2>. The indicated curve is obtained. Here, “total reflection” indicated by a double line in FIG. 7A <2> is calculated by an average value of a plurality of received light amounts at each reflection angle. However, the total reflection is not limited to the average value, and for example, the maximum value may be used. Further, “internal reflection” indicated by a solid line in FIG. 7A <2> is calculated by a value corresponding to the minimum value or the minimum value of the plurality of received light amounts at each reflection angle.

  Here, in FIG. 6, the total light amount of the reflected light RF is considered to be the sum of the light amount of the surface reflected light and the light amount of the internally reflected light. Therefore, if the internal reflection is subtracted from the total reflection in FIG. 7 (a) <2>, “surface reflection” indicated by a dotted line in FIG. 7 (a) <2> is obtained. The value of "surface reflection" indicates the net amount of light of surface reflection. On the other hand, in the case of a low transparency object such as metal, the light receiving light intensity distribution as shown in FIG. 7 (b) <2> is obtained. That is, since the internal reflection is extremely small, the surface reflection has a value close to the total reflection.

  With reference to FIG. 8 and FIG. 9, the internal reflection arithmetic processing for calculating the amount of internal reflection of the object OB based on the above principle will be described.

  First, as shown in FIG. 5, a plurality of received light amount distributions are acquired by reflected light RF from a plurality of irradiation points of the irradiation light IF which is irradiated by changing the light emitting element 12 to be emitted. FIGS. 8A to 8H show an example of a plurality of received light amount distributions obtained from the reflected light RF at eight irradiation points. The horizontal axis of each of FIGS. 8A to 8H is the reflection angle θ (degrees), and the vertical axis is the light reception amount I. As shown in FIGS. 8 (a) to 8 (h), received light amount distributions with respect to the reflection angle θ of the reflected light RF are acquired in various shapes according to the state of the surface of the object OB and the transparency.

  Next, the plurality of received light amount distributions are superimposed to obtain a combined received light amount distribution as shown in FIG. 8 (i). Furthermore, the minimum value of the range (hereinafter, “received light amount width”) of the received light amount at each reflection angle of the received light amount distribution shown in FIG. 8 (i) is connected to obtain the internal reflected light amount distribution shown in FIG. Calculate The internally reflected light amount distribution shown in FIG. 8 (j) indicates the internally reflected light amount of the object OB.

  The connection of the minimum value at each reflection angle θ of the received light amount distribution will be described in more detail with reference to FIG. 9 (a). FIG. 9A shows the value of the light reception amount at each reflection angle θ calculated based on the combined light reception amount distribution shown in FIG. 8I. In the example shown in FIG. 9A, the received light amount values for four reflection angles θ of −20 °, −5 °, 5 °, and 20 ° are shown, and in the present example, the received light amount distributions for eight irradiation points The eight received light amounts are plotted at each reflection angle θ. The width between the minimum value and the maximum value of the eight received light amounts at each reflection angle θ is the “received light amount width ΔI” described above, and FIG. 9A shows an example of the received light amount width ΔI with a reflection angle of 20 °. It is shown. Also, the minimum value at each reflection angle θ is indicated by a black circle. A curve connecting the minimum values is the internally reflected light quantity distribution shown in FIG. 8 (j).

  Here, the calculation processing for calculating the internal light amount distribution shown in FIG. 8 (j) from the minimum value of the light reception light amount width ΔI will be described in more detail. That is, although the minimum value of received light amount width ΔI is connected to calculate the internal light amount distribution in the above example, the present invention is not limited thereto, and the internal light amount distribution may be calculated by a value corresponding to the minimum value by the following method. As in the case of a low transparency object, the light amount of internal reflection may be weak originally, and the light reception light amount width ΔI may include an error such as an error due to the sensitivity of the light receiving element 16 or a measurement error. Therefore, in order to further average the influence of the error, for example, the internal reflection light amount distribution may be calculated by calculating an approximate curve for the minimum value of the light reception light amount width ΔI.

  As a method of calculating the approximate curve, for example, there is polynomial approximation with respect to the minimum value of the received light amount width ΔI. Alternatively, for each reflection angle θ, a predetermined number (for example, three) are extracted in the ascending order from the smallest value of the received light amount width ΔI, and the average value of the three received light amounts at each reflected angle θ is connected to approximate the curve May be calculated. Furthermore, polynomial approximation may be calculated for the three received light quantities at each reflection angle θ.

  Next, with reference to FIG. 9B, an internal reflection calculation processing program for calculating the internal reflection light amount distribution according to the present embodiment will be described. FIG. 9B is a flowchart showing the flow of processing of the internal reflection calculation processing program according to the present embodiment. For example, when an instruction to start execution of the process shown in FIG. 9B is issued by the user via the input unit of the measuring device 10 (not shown), the CPU 100 of the control unit 20 calculates the internal reflection from the storage unit such as the ROM 102. Load and execute the processing program.

  As shown in FIG. 9B, in step S100, the light emitting element 12 of the light emitting device 14 is caused to emit light. In the present embodiment, at least a part of the plurality of light emitting elements 12 is caused to emit light, and the distribution of received light amounts of the reflected light RF from the plurality of irradiation points is acquired. Therefore, although the plurality of light emitting elements 12 are made to emit light, the order of the light emission is not particularly limited. In this embodiment, as shown in FIG. 5 as an example, light is emitted sequentially from the light emitting elements 12A to 12B.

  In the next step S102, the reflected light RF that has reached the light receiving area RA is received by the light receiving element 16 to acquire the received light quantity distribution.

  In the next step S104, it is determined whether all the scheduled light emitting elements 12 have been made to emit light, and if the determination is negative, the process returns to step S100, and the light emitting elements 12 continue to emit light.

  On the other hand, when an affirmative determination is made in step S104, the process proceeds to step S106, and the internal reflection calculation process is performed by the above-described method to acquire the internal reflection light amount distribution. The total surface reflection light amount may be obtained by separately calculating the total reflection light amount and subtracting the internally reflected light amount acquired in step S106 from the calculated total reflection light amount. Thereafter, the internal reflection calculation processing program ends.

Second Embodiment
The measurement apparatus and measurement method according to the present embodiment will be described with reference to FIGS. 10 to 13. In the measurement apparatus 10 according to the above-described embodiment, the irradiation direction of the irradiation light IF is a direction parallel to the optical axis M of the lens 34, that is, the irradiation angle φ is φ from the optical axis M defined in FIG. Although the direction is set to be 0 °, the measurement apparatus according to the present embodiment is provided with an angle setting unit 50 (general name of angle setting units 50A, 50B, and 50C described below) that changes the irradiation angle φ.

  FIG. 10A shows a measuring device 10A provided with the angle setting unit 50A. The angle setting unit 50A is integrally configured with a measurement unit main body 80 including the light emitter 14, the optical system 30, and the light receiver 18 in the measurement device 10A. Then, the inclination angle of the measurement unit main body 80 is configured to be changed, for example, in a direction indicated by a symbol D1 in FIG. 10A by the motor 52 (see FIG. 4). By this, for example, the irradiation direction of the irradiation light L1 is changed to the irradiation direction of the irradiation light L2. The angle setting unit 50A according to the present embodiment corresponds to the "optical module" according to the present invention.

  FIG. 10B shows a measuring device 10B provided with an angle setting unit 50B. In the angle setting unit 50B, the inclination angle of the mounting portion (not shown) for arranging the object OB in the measuring device 10B is changed, for example, in the direction indicated by symbol D2 in FIG. Are configured to be By this, for example, the reflection direction of the reflected light R1 is changed to the reflection direction of the reflected light R2. Needless to say, the change of the reflection angle θ is equivalent to the change of the irradiation angle φ.

  FIG. 10C shows a measuring device 10C provided with the angle setting unit 50C. In the angle setting unit 50C, the diaphragm 40 in the measuring device 10C is configured to be movable by a motor 52 (see FIG. 4), for example, in the direction indicated by symbol D3 in FIG. As a result, the opening 42 of the diaphragm 40 moves, so that, for example, the irradiation direction of the irradiation light L3 is changed to the irradiation direction of the irradiation light L4. The operation of the angle setting unit according to the present embodiment will be described below with reference to FIGS.

  Here, depending on the object OB, the surface may include many planes that form a specific angle with the optical axis M. For example, in the object OB shown in FIG. 11A <1>, a plurality of planes P perpendicular to the optical axis M (see FIG. 1) are included in the surface. A plurality of irradiation lights IF with an irradiation angle φ = 0 ° from a direction parallel to the optical axis M are irradiated to such an object, and a plurality of received light amount distributions acquired by the method described in the above embodiment are overlapped. As shown in FIG. 11 (a) <2>, the reflection angles θ = 0 ° and near 0 ° (peaks shown in FIG. 11 (a) <2>) as shown in FIG. An upswing may occur in the portion of the value PK1). This is based on the feature of the measurement apparatus according to the present embodiment that the reflected light RF reflected at the equal reflection angle θ is received at the same position of the light receiver 18 (that is, the same light receiving element 16). This is because the reflected light RF from P is accumulated in the central portion of the light receiver 18. Hereinafter, the reflection in the plane forming a specific angle may be referred to as “plane reflection”, and the reflected light resulting from the plane reflection may be referred to as “plane reflected light”. Since the reflected light RF includes planar reflection as surface reflection, the result of the internal reflection calculation processing can not be used as internal reflection as it is. As a result, even if the result of the internal reflection calculation processing is subtracted from the total reflection light reception amount, the light reception amount of the surface reflection can not be obtained. The degree of plane reflection depends on the magnitude relationship between the beam diameter of the irradiation light IF and the plane P, and becomes more prominent when the beam diameter is smaller than the area of the plane P.

  On the other hand, when the irradiation angle φ of the irradiation light IF is shifted from 0 °, the peak value of the result of the internal reflection calculation processing moves according to the size of the irradiation angle φ. FIG. 11 (b) shows the result of the internal reflection calculation process in which the irradiation angle φ of 0 ° is changed to 10 ° in FIG. 11 (a) <1>, and FIG. 11 (b) <2> As shown in the graph, the peak value as a result of the internal reflection calculation process is shifted from the peak value PK1 to the peak value PK2. At this time, it is considered from the nature of internal reflection described above that there is no significant change in the amount of light received by internal reflection even if the irradiation angle φ is changed. Therefore, the internal reflection operation processing (hereinafter, “second internal reflection operation processing”) is further performed on the result of performing the plurality of internal reflection operation processing (hereinafter, referred to as “first internal reflection operation processing”) by changing the irradiation angle φ. It is considered that the received light amount distribution from which the received light amount corresponding to the plane reflection is removed is acquired, and the received light amount distribution indicates internal reflection.

  The second internal reflection calculation process will be described in more detail with reference to FIG. <1> to <5> in FIG. 12A show the results of execution of the first internal reflection calculation process for five different irradiation angles φ. As shown in FIG. 12 (a) <1> to <5>, the result of the first internal reflection calculation process in which the peak position is moved according to the irradiation angle φ is obtained. In the present embodiment, the second internal reflection calculation process is further performed on the distributions shown in <1> to <5> of FIG. The contents of the second internal reflection calculation process are the same as the internal reflection calculation process described with reference to FIG. FIG. 12B shows the result of performing the second internal reflection calculation process. As shown in FIG. 12 (b), when the second internal reflection calculation process is executed, a distribution from which a portion of the distribution corresponding to planar reflection shown in FIGS. 12 (a) <1> to <5> is removed is obtained. Ru. It is considered that the result of execution of the second internal reflection calculation process indicates the internal reflection of the object OB shown in FIG.

  Next, with reference to FIG. 13, a second internal reflection calculation processing program for calculating the internal reflection light amount distribution executed in the present embodiment will be described. FIG. 13 is a flowchart showing a flow of processing of a second internal reflection calculation processing program according to the present embodiment. For example, when an instruction to start execution of the process shown in FIG. 13 is given by the user via the input unit of the measuring device 10A (10B, 10C) (not shown), the CPU 100 of the control unit 20 Load and execute internal reflection calculation processing program 2

  In step S200, the irradiation angle φ is set (initial setting). Although there is no limitation on the initial setting value of the irradiation angle φ, for example, the irradiation angle φ is set to 0 °. The setting of the irradiation angle φ is performed by the above-described angle setting unit 50.

  The subsequent steps S202 to S208 are similar to the steps S100 to S106 described in FIG. The first internally reflected light amount calculation in step S208 is the same process as the internally reflected light amount calculation in step S106, and as a result of the process, one of the distributions shown in <1> to <5> of FIG. For example, <1> is acquired.

In the next step S210, it is determined whether or not the internal reflected light amount calculation has been completed for all of the irradiation angles φ set in advance. If the determination is negative, the process returns to step S200, and the process is repeated from the setting of the irradiation angle φ. On the other hand, in the case of a positive determination, the process proceeds to step S212.
At this point, for example, distributions shown in <1> to <5> of FIG. 12A are acquired.

  In step S212, the second internal reflection light amount calculation is performed, and then the second internal reflection calculation processing program ends. The second internally reflected light amount calculation is a process of acquiring the distribution shown in FIG. 12 (b) by further performing the internal reflection operation on the distributions <1> to <5> in FIG. 12 (a) described above. is there. The light quantity distribution acquired in step S212 indicates the internally reflected light quantity of the object OB including many planar areas of the specific reflection angle described in FIG. If necessary, the distribution of surface reflection at the irradiation angle φ is calculated by subtracting the distribution of light amounts of internal reflection calculated in step S212 from the distribution of light amounts of total reflection at a certain irradiation angle φ.

  Here, the size and direction of the irradiation angle φ set by the angle setting unit 50 according to the present embodiment may be set in advance. Also, the present invention is not limited thereto. For example, with a predetermined irradiation angle φ and a direction as a reference position, the irradiation to be set next according to the result of the first internal reflection calculation process performed in the state of the reference position The size and direction of the angle φ may be set. As the reference position, for example, the irradiation angle φ may be set to 0 °.

  In each of the above-described embodiments, the light emitters 14 are described by exemplifying a mode in which the light emitting elements 12 are arranged in one line in one direction. However, the present invention is not limited to this. Further, at that time, the emission wavelength of the light emitting element 12 may be made different for each row. By making the light emission wavelength of the light emitting element 12 different for each row and emitting light, for example, the wavelength dependency of surface reflection and internal reflection of the object OB is measured.

  In each of the above-described embodiments, the lens 32 and the lens 34 are illustrated as a substantially circular convex lens. However, the present invention is not limited to this, and lenses of other forms, for example, an aspheric lens may be used. Good. Furthermore, in each lens, unnecessary portions where light flux is not transmitted may be deleted. Thereby, the measuring device 10 is further miniaturized.

10, 10A, 10B, 10C Measuring device 12, 12A, 12B, 12C Light emitting element 14 Light emitter 14A Substrate 16 Light receiving element 18 Light receiving element 18A Substrate 18B Opening 20 Control part 30 Optical system 32 Lens 34 Lens 40 Aperture 42 A 42A Opening edge 50, 50A, 50B, 50C Angle setting unit 52 Motor 80 Measuring unit body 100 CPU
102 ROM
104 RAM
200 Surface BUS Bus D Dimension D1, D2 Direction IF Irradiated light RF Reflected light L1, L2, L3, L4 Irradiated light M Optical axis P Plane PK1, PK2 Peak value RA Light receiving area R1, R2 Reflected light T Measurement area θ Reflection angle φ Irradiation angle

Claims (14)

A light emitting unit including a plurality of light emitting elements and emitting light to be irradiated to an object;
A first lens that changes the degree of divergence of the irradiation light emitted from the light emitting unit;
A diaphragm unit that narrows the irradiation light emitted from the first lens;
A second lens that condenses the irradiation light that has passed through the diaphragm so as to be irradiated from a predetermined direction of the object;
A plurality of light receiving elements are provided and disposed between the diaphragm unit and the second lens, and the reflected light that is emitted from the object and reflected by the irradiation light is received by the plurality of light receiving elements and the reflection angle with respect to the reflection angle is obtained. A light receiving unit that outputs a received light amount distribution;
The light emitting unit is controlled to emit at least a part of the plurality of light emitting elements to emit a plurality of irradiation lights, and the plurality of irradiation lights are irradiated to the target object to receive reflected light which is reflected and is plurality The light receiving unit is controlled to output the received light amount distribution, and the minimum value of the received light amount width for each reflection angle calculated from the combined received light amount distribution obtained by combining the plurality of received light amount distributions with respect to the reflected angle And a calculation unit that calculates an approximate curve indicating a distribution. The measurement device according to claim 1, wherein the calculation unit extracts a light reception light amount in a predetermined range for each light reception light amount width, and calculates the approximate curve using the light reception light amount in the predetermined range. The measurement device according to claim 2, wherein the calculation unit extracts a minimum value of the light reception amount for each of the light reception light width, and calculates the approximate curve using the minimum value. The measuring apparatus according to claim 3, wherein the calculation unit connects the minimum values to calculate the approximate curve. The measuring device according to claim 3, wherein the calculation unit performs polynomial approximation of the minimum value to calculate the approximate curve. The calculation unit extracts the light reception amount in a predetermined range from the minimum value for each light reception light width, and calculates the approximate curve using the light reception amount in the predetermined range. Measuring device. The measuring device according to claim 6, wherein the calculation unit calculates the approximate curve by connecting an average value of the minimum value and the maximum value of the light reception amount in the predetermined range. The measurement device according to any one of claims 1 to 7, wherein the predetermined direction is a direction parallel to the optical axis of the second lens. The predetermined direction is a plurality of directions forming a plurality of predetermined angles with respect to a direction parallel to the optical axis of the second lens,
9. The calculation unit calculates the approximate curve in each of the plurality of directions, and further calculates a distribution with respect to a reflection angle of a minimum value of a combined approximate curve in which a plurality of the approximate curves are combined. The measuring device according to 1 or 2. It further includes setting means for setting an irradiation direction of the irradiation light,
The measurement device according to claim 9, wherein the calculation unit calculates a distribution with respect to a reflection angle of the minimum value of the synthetic approximate curve while controlling the setting unit such that the irradiation direction of the irradiation light becomes the plurality of directions. The light emitting unit, the first lens, the diaphragm unit, the second lens, and the light receiving unit are integrated in which the setting means has a variable inclination angle with respect to the direction perpendicular to the object. The measurement apparatus according to claim 10, which is an optical module. The measurement apparatus according to claim 10, wherein the setting unit is a mounting portion of the object capable of setting an inclination angle of the object. The measurement apparatus according to claim 10, wherein the setting unit is a position change unit that changes a position of the aperture. A light emitting unit including a plurality of light emitting elements and emitting light to be irradiated to an object;
A first lens that changes the degree of divergence of the irradiation light emitted from the light emitting unit;
A diaphragm unit that narrows the irradiation light emitted from the first lens;
A second lens that condenses the irradiation light that has passed through the diaphragm so as to be irradiated from a predetermined direction of the object;
A plurality of light receiving elements are provided and disposed between the diaphragm unit and the second lens, and the reflected light that is emitted from the object and reflected by the irradiation light is received by the plurality of light receiving elements and the reflection angle with respect to the reflection angle is obtained. A measuring method using a measuring device including a light receiving unit that outputs a light receiving amount distribution,
The light emitting unit is controlled such that at least a part of the plurality of light emitting elements emits light to emit a plurality of irradiation lights by the operation unit, and the plurality of irradiation lights are reflected on the object and reflected light is reflected And control the light receiving unit to output a plurality of received light amount distributions, and the minimum value of the received light amount width for each reflection angle calculated from the combined received light amount distribution obtained by combining the plurality of received light amount distributions A measurement method for calculating an approximate curve indicating a distribution with respect to the reflection angle.