JP6717199B2 - Multi-angle colorimeter - Google Patents

Description

The present invention relates to a multi-angle colorimeter that receives reflected light from a measurement point at a plurality of reflection angles and obtains color information of a measurement surface on which the measurement point is arranged.

In a coating formed by using a paint containing a glitter material such as metallic and pearl color paints, the reflected light on the surface of the glitter material has an angle dependence. Therefore, the color of the coating recognized by the observer may be different depending on the direction in which the observer observes the coating (also referred to as the observation direction). Therefore, when the object whose color recognized by the observer may be different depending on the observation direction is a color measurement object (also referred to as a color measurement object), the light from the color measurement object is at one angle. It is not possible to evaluate the difference in brightness or color depending on the viewing direction only by receiving the light.

Therefore, when the object whose color recognized depending on the viewing direction is a colorimetric object, for example, multi-direction illumination-one-direction light receiving system or one-direction illumination-multi-direction light receiving system, multi-angle color measurement A meter may be adopted (for example, Patent Document 1). The multi-directional illumination-one-direction light receiving system is a system in which a colorimetric object is sequentially illuminated from a plurality of directions and light from the colorimetric object is received in one direction. The one-way illumination-multidirectional light receiving method is a method of illuminating a colorimetric object from one direction and receiving light from the colorimetric object sequentially or simultaneously in a plurality of directions.

Further, in the multi-angle colorimeter disclosed in Patent Document 1, two measured values corresponding to the light received by each pair of light receiving portions provided symmetrically with respect to the reference axis are averaged. Thus, when the surface of the colorimetric object has a curvature, even if the reference axis is inclined with respect to the normal line of the surface of the colorimetric object during colorimetry, the color depending on the viewing direction The difference can be measured properly.

International Publication No. 2012/147488

In a multi-angle colorimeter, a large number of optical elements (for example, a light emitting element and a light receiving element) arranged inside the apparatus are constrained in terms of angular relationship. In particular, when the light receiving portions are provided in the axially symmetrical manner as described above, a large number of optical elements are arranged, and the arrangement constraint is further increased. Therefore, there has been a demand for a multi-angle colorimeter capable of improving the freedom of layout of each optical element inside the device.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a multi-angle colorimeter capable of improving the degree of freedom in layout of each optical element inside the apparatus.

In order to solve the above problems, a multi-angle colorimeter according to a first aspect is different from an illumination unit that irradiates a measurement point on a target surface with light and a reflected light from the measurement point of the light. A plurality of light receiving portions that receive light at a plurality of reflection angles and the remaining light except at least two lights of the plurality of light received by the plurality of light receiving portions are selectively guided to a detection position in a specific order. and selecting light guide, is disposed in the detection position, based on the light detection unit for photoelectrically converting light emitted from the selected light guide comprises a detection result of the previous Kisukuna without even two light, the the estimated information and the at least two optical estimating the detection result of the different specific light reflection angles are generated, pre-Symbol least two light is detected by the light detecting portion are mixed optically of the reflected light Thus, the estimation information is generated.
Multi-angle colorimeter according to the second aspect is a multi-angle colorimeter according to the first aspect, toward the specular reflection direction or RaHajime reference plane of the illumination light irradiated to the measurement point An angle in a direction inclined by X degrees (0≦X≦180) is expressed as an aspecular angle X degrees, and a direction inclined by X degrees (0≦X≦180) in a direction away from the regular reflection direction from the reference plane. when representing the angle between aspecular angle -X degree, by the aspecular angle of the plurality of light is detected at a different at least two light are mixed optically the light detecting unit, wherein the estimation information There are generated, the reference surface is characterized by flat der Rukoto including a virtual central axis intersects the measuring surface as the target surface at the measurement point.

A multi-angle colorimeter according to a third aspect is the multi-angle colorimeter according to the first or second aspect, wherein the selective light guide has a plurality of entrances and a single exit. It has a bundle fiber, It is characterized in that the at least two lights are optically mixed in the path of the bundle fiber and detected by the photo-detecting unit.

Multi-angle colorimeter according to the fourth aspect, to no first aspect there is provided a multi-angle colorimeter according to any one of the third aspect, respectively provided in the middle of the optical path of said at least two optical , At least two filters having respective transmittances according to respective reflection angles of the at least two lights and reflectances of the target surface.

A multi-angle colorimeter according to a fifth aspect is the multi-angle colorimeter according to any of the first to fourth aspects, wherein the maximum angle of the reflection angles of the at least two lights is It is characterized in that the reflection angle of the specific light is included in an angle range sandwiched between the minimum angle and the minimum angle.

The multi-angle colorimeter according to the sixth aspect is arranged symmetrically with respect to a reference plane that is a plane including a virtual central axis that intersects the measurement plane at the measurement point, and emits light toward the measurement point. an illumination unit, disposed symmetrically with respect to the reference plane, and a plurality of light receiving portions for receiving light reflected from the measuring point at different reflection angles, at least two of the plurality of light received respectively by the plurality of light receiving portions Selective light guide part that selectively guides the remaining light excluding two lights to a detection position in a specific order, and a light detection part that is arranged at the detection position and photoelectrically converts the light emitted from the selective light guide part. When provided with, in both the as viewed from the reference plane on one side and the other side on the basis of the detection result even before Kisukuna no two light are obtained is guided to the light detector, the reflection estimation information for estimating the detection result of the different specific light reflection angle than the out of light at least two of the light is generated, the previous SL least two light is detected by the light detecting portion are mixed optically According to the above, the estimation information is generated.
A multi-angle colorimeter according to a seventh aspect is the multi-angle colorimeter according to the sixth aspect, wherein the multi-angle colorimeter is in a direction approaching the reference plane from a regular reflection direction of illumination light applied to the measurement point. An angle in a direction inclined by X degrees (0≦X≦180) is expressed as an aspecular angle X degrees, and a direction inclined by X degrees (0≦X≦180) in a direction away from the regular reflection direction from the reference plane. when representing the angle between aspecular angle -X degree, by the aspecular angle of the plurality of light is detected at a different at least two light are mixed optically the light detecting unit, wherein the estimation information Is generated.

A multi-angle colorimeter according to an eighth aspect is the multi-angle colorimeter according to the sixth aspect, wherein the illumination light radiated to the measurement points is provided on both the one side and the other side. An angle of a direction tilted by X degrees (0≦X≦180) from the regular reflection direction toward the reference plane is expressed as an aspecular angle X degrees, and X degrees (a degree apart from the regular reflection direction to the reference plane). 0≦X≦180) when the angle in a direction inclined by 0≦X≦180) is expressed as an aspecular angle−X degrees, the at least two lights are light having an aspecular angle of 105 degrees and an aspecular angle on both of the one side and the other side. And the specific light is light having an aspecular angle of 110 degrees.

In the multi-angle colorimeter according to the first to eighth aspects of the present invention, based on the detection result of at least two lights out of a plurality of lights having different reflection angles, the at least two lights out of the reflected lights. It is estimated that the detection result of the specific light having a different reflection angle from is detected. As a result, the detection result of the specific light at the position where the optical elements for guiding light are not actually arranged (the position where the specific light passes) can be estimated. In this way, the detection result can be obtained even at an angle without each optical element, so that the degree of freedom in layout of each member arranged in the multi-angle colorimeter is improved. As a result, it is possible to achieve miniaturization as compared with a conventional multi-angle colorimeter in which each optical element for guiding light is arranged at an angular position where a detection result is desired to be acquired.

A multi-angle colorimeter according to a sixth aspect of the present invention is configured such that a plurality of illumination units arranged symmetrically with respect to a reference plane and a plurality of light receiving units arranged symmetrically with respect to the reference plane. And a selective light guide section and a light detection section, which is a so-called double-pass type colorimeter. The double-pass multi-angle colorimeter has the advantage that the measurement error due to the attitude error of the multi-angle colorimeter is reduced, while the number of each member arranged in the multi-angle colorimeter is reduced. However, there is a drawback that the degree of freedom in layout of each member is low due to the large number of components (and thus the multi-angle colorimeter becomes large). Further, in the sixth aspect of the present invention, based on the detection result obtained by guiding at least two lights having different reflection angles to both sides of the one side and the other side when viewed from the reference surface to the photodetector. In addition, the detection result of the specific light having a reflection angle different from that of the at least two lights among the reflected lights is estimated. Therefore, in the sixth aspect of the present invention, the estimation technique can be used to improve the degree of freedom in layout and reduce the size of the device. Therefore, the advantages of the double-pass method can be obtained while the drawbacks of the double-pass method can be compensated. desirable.

It is a perspective view which illustrates the appearance of a multi-angle colorimeter. It is a schematic diagram which illustrates the angular relationship of the central axis of a main-body part and the normal line of a measurement surface. It is a figure which illustrates the angular relationship of the illumination part and the light-receiving part, and the normal line of a measurement surface. It is a graph which illustrates the distribution of the intensity of reflected light. It is a figure which illustrates the angular relationship of the illumination part and the light-receiving part, and the normal line of a measurement surface. It is a graph which illustrates the distribution of the intensity of reflected light. It is a schematic diagram which illustrates the main structures of a multi-angle colorimeter. It is sectional drawing which shows especially the peripheral part of an opening among the structures of a multi-angle colorimeter. It is a schematic diagram which illustrates the structure of a spectroscopic unit. It is a schematic diagram which illustrates the structure of a spectroscopic unit. It is a figure which illustrates typically the arrangement|positioning of several opening part and several emission part. It is a front view which illustrates the composition of a shade part typically. It is a flowchart which shows the flow of the color measurement operation of a multi-angle colorimeter. It is a flowchart which shows the flow of the color measurement operation of a multi-angle colorimeter. It is a flowchart which shows the flow of the color measurement operation of a multi-angle colorimeter. It is a figure which shows the relationship between the as angle and reflectance in Silver Metallic. It is a schematic diagram which showed the peripheral part of the lens among the multi-angle colorimeters which concern on a modification. It is a schematic diagram which showed the peripheral part of the lens among the multi-angle colorimeters which concern on a modification. It is a schematic diagram which showed the peripheral part of the lens among the multi-angle colorimeters which concern on a modification. It is a schematic diagram which showed the peripheral part of the lens among the multi-angle colorimeters which concern on a modification. It is a schematic diagram which illustrates the main structures of the multi-angle colorimeter which concerns on a modification.

Embodiments and modifications of the present invention will be described below with reference to the drawings. In the drawings, parts having similar configurations and functions are designated by the same reference numerals, and redundant description will be omitted in the following description. The drawings are schematically shown, and the size and positional relationship of various structures in each drawing may be appropriately changed. 9 to 12 show a right-handed XYZ coordinate system in which the +X direction is the direction in which the optical axis 6La of the optical system 6L of the spectroscopic unit extends (the right direction in the drawing of FIG. 9).

<1 embodiment>
<1.1 Appearance of multi-angle colorimeter>
FIG. 1 is a perspective view showing the appearance of a multi-angle colorimeter 1 according to the embodiment. The multi-angle colorimeter 1 measures the color of a measured portion by receiving light from the measured portion of an object at a plurality of angles and obtaining a spectral reflectance. In the present embodiment, the multi-angle colorimeter 1 is a small-sized and portable portable colorimeter.

As shown in FIG. 1, the multi-angle colorimeter 1 includes a box-shaped main body 2 in which various configurations are built. The main body portion 2 has, for example, an opening 3 for measurement formed in the bottom wall and an operation display portion 4 arranged at an appropriate position on the surface. The operation display unit 4 has an operation unit 91 (see FIG. 7) and a display unit 92 (see FIG. 7) that displays the measurement result of the multi-angle colorimeter 1. The operation unit 91 is composed of, for example, various buttons and switches. The display unit 92 is composed of, for example, a liquid crystal display or the like. As the operation display unit 4, for example, a touch panel having both functions of the operation unit 91 and the display unit 92 may be adopted.

FIG. 2 is a schematic diagram for explaining an angular relationship between the main body 2 and the surface (also referred to as a measurement surface) of the DUT 5. In FIG. 2, the angular relationship between the virtual center axis 2n of the main body 2 of the multi-angle colorimeter 1 and the normal line 5n of the measurement surface is schematically shown.

As shown in FIG. 2, color measurement is performed with the measurement opening 3 of the multi-angle colorimeter 1 facing the object 5. At this time, a region (also referred to as a colorimetric region) 5a of the measurement surface of the DUT 5 facing the opening 3 is an object of colorimetry. When the color measurement is performed, the main body 2 is arranged so as to face the surface of the DUT 5 so that the central axis 2n of the main body 2 and the virtual normal line 5n of the measurement region 5a coincide with each other. To be done. In the present embodiment, the central axis 2n is a normal line of the opening 3 that passes through substantially the center of the opening 3. Further, the normal line 5n is a normal line at a point (also referred to as a measurement point) 5p that intersects with the central axis 2n in the measurement region 5a.

By the way, when the measurement surface of the DUT 5 has a curved surface like a bumper of an automobile, it is difficult to make the central axis 2n of the main body 2 and the normal line 5n of the measurement surface match exactly. Therefore, in general, there are many cases where the central axis 2n and the normal line 5n do not coincide with each other. For example, the central axis 2n is inclined with respect to the normal line 5n about the measurement point 5p (also referred to as an inclined state). ..

<1.2 Symmetrical arrangement of illumination unit and light receiving unit>
Hereinafter, a portion in which a plurality of light receiving portions are arranged for one illumination portion and which is configured by one illumination portion and a plurality of light receiving portions is referred to as one light emitting/receiving unit. The one light emitting/receiving unit illuminates the DUT 5 from one direction, and receives the light from the DUT 5 in a plurality of directions. Configuration of a unidirectional illumination-multidirectional light receiving type multi-angle colorimeter have. Thereby, the reflected light generated by the light from one illumination unit being reflected on the measurement surface is received by the plurality of light receiving units at different angles, and the detection function of the reflected light can be enhanced.

Further, in the multi-angle colorimeter 1 according to the present embodiment, a pair of light emitting/receiving units are arranged so as to have a line-symmetrical relationship with the central axis 2n as a symmetrical axis (a symmetrical arrangement method or a double-pass method). (Also called) has been adopted.

Here, the advantage of adopting the symmetrical arrangement method will be described. Here, in order to avoid complication of the description, a simple model in which one light emitting/receiving unit has one illuminating unit and one light receiving unit will be described.

3 to 6 are diagrams for explaining the angular relationship between the normal line 5n of the measurement surface 5s and the central axis 2n of the main body 2 and the phenomenon that occurs depending on the angular relationship. 4 and 6, the vertical axis represents the intensity of reflected light and the horizontal axis represents the angle A based on the normal line 5n. 3 and 5, the normal line 5n is used as a reference, the clockwise rotation angle about the measurement point 5p is a positive angle, and the counterclockwise rotation angle is It is a negative angle.

FIG. 3 shows an angular relationship between the illumination units E1 and E2, the light receiving units R1 and R2, and the normal line 5n of the measurement surface 5s when the central axis 2n of the main body unit 2 and the normal line 5n coincide with each other. ing. In this case, as shown in FIG. 3, the illumination light l1 emitted from the illumination unit E1 that is arranged on the virtual line that passes through the measurement point 5p and is inclined by the angle +θ from the normal line 5n is on the measurement surface 5s. The measurement point 5p is irradiated and reflected light is generated at the measurement point 5p. The reflected light passes through the measurement point 5p and is arranged on a virtual line inclined by an angle +(θ+α) from the normal line 5n, or the reflected light passes through the measurement point 5p and is inclined by −(θ+α) from the normal line 5n. The light is received by the light receiving portion R2 arranged on the virtual line. Further, the illumination light 12 emitted from the illumination unit E2 arranged on the virtual line that passes through the measurement point 5p and is inclined by the angle −θ from the normal line 5n is irradiated to the measurement point 5p, and at the measurement point 5p on the measurement surface 5s. Reflected light is generated. The reflected light is received by the light receiving unit R1 or the light receiving unit R2.

FIG. 4 shows a distribution of the intensity of reflected light generated on the measurement surface 5s when the illumination portions E1 and E2 and the light receiving portions R1 and R2 and the normal 5n of the measurement surface 5s have the angular relationship shown in FIG. It is a graph.

As shown in FIGS. 3 and 4, an optical path of light (also referred to as specular reflection light) generated by regular reflection of the illumination lights l1 and l2 from the illumination units E1 and E2 on the measurement surface 5s, and the illumination light l1. The optical path with which l2 is irradiated toward the measurement surface 5s has a line-symmetrical relationship with the normal line 5n as the axis of symmetry. That is, the regular reflection light corresponding to the illumination light l1 from the illumination unit E1 is reflected by the measurement surface 5s and emitted toward the illumination unit E2, and the regular reflection light corresponding to the illumination light l2 from the illumination unit E2 is , Is reflected by the measurement surface 5s and is emitted toward the illumination unit E1. Further, as shown in FIG. 4, on the measurement surface 5s, in response to the irradiation of the illumination lights l1 and l2 from the illumination units E1 and E2, diffuse reflection occurs around the specular reflection light centered on the specular reflection light. It produces reflected light (also called diffuse reflected light).

Here, the intensity distribution of the reflected light including the specularly reflected light and the diffusely reflected light is formed by the sum of the following three types of components [i] to [iii].

[I] A component of a sharp peak at the angle of the optical path of specular reflection light.

[Ii] A component that can be approximated by a Gaussian function that symmetrically attenuates at both positive and negative angles around the angle of the optical path of specularly reflected light.

[Iii] A component related to the intensity of diffused light that has a peak at the angle of the normal line 5n of the measurement surface 5s and can be regarded as substantially constant regardless of the angle.

It should be noted that the component [ii] that occupies the intensity distribution of the reflected light is high at an angle relatively close to the angle of the optical path of the specularly reflected light, and the component [ii] is relatively far from the optical path of the specularly reflected light. The ratio of the component [iii] that occupies the light intensity distribution is high.

Therefore, the intensity of the reflected light corresponding to the irradiation of the illumination light 11 from the illumination unit E1 to the measurement surface 5s can be approximately represented by R(A+θ), and the intensity of the reflected light from the illumination unit E2 to the measurement surface 5s can be expressed. The intensity of the reflected light corresponding to the irradiation of the illumination light 12 can be approximately represented by R(A−θ). At this time, the reflected light having the intensity R(+α) can be received by the light receiving unit R1 arranged on the virtual line that passes through the measurement point 5p and is inclined by the angle (θ+α) from the normal 5n. Further, the light receiving portion R2, which is disposed on the virtual line that passes through the measurement point 5p and is inclined by the angle −(θ+α) from the normal line 5n, can receive the reflected light having the intensity R(−α). Then, for the intensities R(+α) and R(−α) shown by the shaded areas in FIG. 4, the relationship of R(+α)=R(−α) is established.

On the other hand, in FIG. 5, when the central axis 2n of the main body 2 is an imaginary line that passes through the measurement point 5p and is inclined by the angle −φ from the normal 5n, measurement is performed with the illumination units E1 and E2 and the light receiving units R1 and R2. The angular relationship between the surface 5s and the normal 5n is shown. In this case, the illumination unit E1 is arranged on a virtual line inclined by an angle +(θ−φ) with respect to the normal line 5n, and the illumination unit E2 is virtually inclined by an angle −(θ+φ) with respect to the normal line 5n. Arranged on the line. Further, in this case, the light receiving portion R1 is arranged on a virtual line that is tilted at an angle +(θ+α−φ) with respect to the normal line 5n, and the light receiving portion R2 is tilted at an angle −(θ+α+φ) with respect to the normal line 5n. Placed on the virtual line.

FIG. 6 shows a distribution of the intensity of reflected light generated on the measurement surface 5s when the illumination portions E1 and E2 and the light receiving portions R1 and R2 and the normal 5n of the measurement surface 5s have the angular relationship shown in FIG. It is a graph.

Here, the intensity of the reflected light corresponding to the irradiation of the illumination light 11 from the illumination unit E1 to the measurement surface 5s can be approximately expressed as R(A+(θ−φ)), and from the illumination unit E2. The intensity of the reflected light according to the irradiation of the illumination light 12 can be approximately represented by R(A−(θ+φ)). At this time, the light receiving portion R1 disposed on the virtual line that passes through the measurement point 5p and is inclined by the angle (θ+α−φ) from the normal line 5n can receive the reflected light having the intensity R(α−2φ). Further, the light receiving portion R2 arranged on the virtual line that passes through the measurement point 5p and is inclined by the angle −(θ+α+φ) from the normal line 5n can receive the reflected light having the intensity R(−α−2φ). Then, for the intensities R(α-2φ) and R(-α-2φ) indicated by the shaded areas in FIG. 6, the relationship of R(α-2φ)≠R(-α-2φ) is established. To do.

As shown in FIGS. 4 and 6, when the central axis 2n of the main body 2 is inclined with respect to the normal line 5n of the measurement surface 5s, the case where the central axis 2n and the normal line 5n coincide with each other In comparison, the intensity of the reflected light received by the light receiving unit R1 increases, and the intensity of the reflected light received by the light receiving unit R2 decreases. However, regarding the total value of the intensities of the reflected light received by the light receiving portions R1 and R2, either the case where the central axis 2n and the normal line 5n coincide or the case where the central axis 2n is inclined with respect to the normal line 5n are used. In the case of, it is almost the same. That is, the relationship of R(−α)+R(+α)=R(α−2φ)+R(−α−2φ) approximately holds. Note that such an approximate relationship can be established when the angle φ of inclination of the central axis 2n with respect to the normal 5n is relatively small.

In this way, if color measurement is performed in a posture in which the central axis 2n of the main body 2 and the normal 5n of the measurement surface 5s do not match, from the information of reflected light obtained only by the light receiving unit R1 (or light receiving unit R2). Cannot obtain correct color information of the measurement surface 5s existing at the measurement point 5p. However, even in a tilted state in which the central axis 2n is slightly tilted with respect to the normal 5n, the information of the reflected light is independently acquired by the light receiving portions R1 and R2 that have an optically line-symmetrical relationship. And the total value of the intensities of the reflected light received by the light receiving portions R1 and R2 is considered to be substantially equal. Therefore, by performing the process of calculating the average value of the intensities of the reflected light received by the light receiving units R1 and R2, the error (also referred to as the attitude error) in the detection of the reflected light that occurs in the tilted state can be corrected.

<1.3 Main configuration of multi-angle colorimeter>
FIG. 7 is a schematic view illustrating the main configuration of the multi-angle colorimeter 1. FIG. 8 is a cross-sectional view showing the periphery of the opening 3 in the configuration of the multi-angle colorimeter 1.

As shown in FIG. 7, the multi-angle colorimeter 1 is provided with a spectroscopic unit 6, a control unit 7, a storage unit 8, an operation display unit 9, and a light emitting and receiving unit 10 in the main body 2.

<1.3.1 Emitter/Receiver>
The light projecting/receiving unit 10 includes two illumination units L1a, L1b, nine lenses C1a to C4a, C1b to C4b, C5 as light receiving units, and eleven light guiding units F1a to F4a, F1b to F4b, F5, F6a,. It has F6b.

The lighting unit L1a includes a lighting unit E1a, a light emitting circuit Ct1a, a half mirror H1a, and a lens C6a. Further, the lighting unit L1b includes a lighting unit E1b, a light emitting circuit Ct1b, a half mirror H1b, and a lens C6b.

The illuminating section E1a and the illuminating section E1b are arranged symmetrically with respect to a reference plane (a plane including the central axis 2n and extending in the front-rear direction in the view of FIG. 7). The lenses C1a to C4a and the lenses C1b to C4b are also arranged symmetrically with respect to the reference plane. The lens C5 is arranged on the reference plane. The illumination unit E1a, the illumination unit E1b, and the lenses C1a to C4a, C1b to C4b, and C5 are arranged on a plane including the central axis 2n and perpendicular to the reference plane (also referred to as “arrangement plane”).

The illumination units E1a and E1b irradiate light toward a measurement point 5p defined on the central axis 2n. As shown in FIG. 7, the illumination unit E1a is arranged on the right side in the drawing when viewed from the reference plane, and the illumination unit E1b is disposed on the left side in the drawing when viewed from the reference plane. The angle formed by the virtual line connecting the illuminating section E1a and the measuring point 5p and the central axis 2n is 45 degrees, and the angle formed by the virtual line connecting the illuminating section E1b and the measuring point 5p and the central axis 2n is also 45 degrees. is there.

Each of the illumination units E1a and E1b includes, for example, a light source such as a xenon flash lamp, a regulation plate that regulates a light beam emitted from the light source, and a collimator that converts a light beam emitted from the light source and regulated by the regulation plate into parallel light. And a lens.

The light emitting circuit Ct1a is provided in the vicinity of the lighting unit E1a and causes the light source of the lighting unit E1a to emit light under the control of the control unit 7. Like the light emitting circuit Ct1a, the light emitting circuit Ct1b is provided in the vicinity of the lighting unit E1b and causes the light source of the lighting unit E1b to emit light under the control of the control unit 7.

The half mirror H1a reflects a part of the light emitted from the illumination unit E1a toward the lens C6a and transmits the remaining light (also referred to as illumination light) toward the measurement point 5p. Similar to the half mirror H1a, the half mirror H1b reflects a part of the light emitted from the illumination unit E1b toward the lens C6b and directs the remaining light (also referred to as illumination light) to the measurement point 5p. To make it transparent.

The lens C6a (reference light receiving portion) receives the light reflected by the half mirror H1a among the light emitted from the illumination portion E1a, and the reflected light is an incident portion located at one end of the light guide portion F6a. The light is focused toward I6a. The lens C6b (reference light receiving unit) receives the light reflected by the half mirror H1b among the light emitted from the illumination unit E1b, and the reflected light is an incident unit located at one end of the light guiding unit F6b. Focus the light toward I6b.

That is, when the illumination section E1a emits light, part of the light is received by the lens C6a, and the rest of the light is emitted toward the measurement point 5p. When the illumination unit E1b emits light, part of the light is received by the lens C6b, and the rest of the light is emitted toward the measurement point 5p.

The lenses C1a to C4a, C1b to C4b, and C5 are configured by, for example, condenser lenses. As shown in FIG. 7, the lenses C1a to C4a are arranged on the right side as viewed from the central axis 2n, the lens C5 is arranged on the central axis 2n, and the lenses C1b to C4b are arranged on the left side as viewed from the central axis 2n. To be done. In the present embodiment, virtual lines that virtually connect the lenses C1a to C4a, C1b to C4b, and C5 and the measurement point 5p coincide with the optical axes of the lenses C1a to C4a, C1b to C4b, and C5. An angle formed by a virtual line connecting the lens C1a and the measurement point 5p and the central axis 2n is 70 degrees. An angle formed by a virtual line connecting the lens C2a and the measurement point 5p and the central axis 2n is 60 degrees. An angle formed by a virtual line connecting the lens C3a and the measurement point 5p and the central axis 2n is 30 degrees. The angle formed by the virtual line connecting the lens C4a and the measurement point 5p and the central axis 2n is 20 degrees. An angle formed by a virtual line connecting the lens C5 and the measurement point 5p and the central axis 2n is 0 degree. An angle formed by a virtual line connecting the lens C1b and the measurement point 5p and the central axis 2n is 70 degrees. An angle formed by a virtual line connecting the lens C2b and the measurement point 5p and the central axis 2n is 60 degrees. An angle formed by a virtual line connecting the lens C3b and the measurement point 5p and the central axis 2n is 30 degrees. The angle formed by the virtual line connecting the lens C4b and the measurement point 5p and the central axis 2n is 20 degrees.

Each group symmetrically arranged with respect to the reference plane (specifically, a group of the lens C1a and the lens C1b, a group of the lens C2a and the lens C2b, a group of the lens C3a and the lens C3b, and a lens C4a and the lens C4b. Group) respectively constitutes a pair of lenses. With such a configuration, even if the normal line 5n of the measurement surface 5s at the measurement point 5p is tilted within the reference plane with respect to the central axis 2n, the measurement accuracy of the color information related to the measurement surface 5s can be secured by the double pass method. ..

When the central axis 2n is perpendicular to the measurement surface 5s, the array surface is a plane including the central axis 2n and perpendicular to the measurement surface 5s. Such a surface is called, for example, a main geometry surface. A plane (reference plane) orthogonal to the array plane (main geometry plane) is called, for example, a sub geometry plane. In the multi-angle colorimeter 1 according to the present embodiment, the illumination parts E1a and E1b are symmetrically arranged on the main geometry surface with the central axis 2n as the axis of symmetry, and the lenses C1a to C4a and the lenses C1b to C4b is arranged symmetrically.

The lenses C1a to C4a, C1b to C4b, and C5 reflect the reflected light from the measurement point 5p at the incident portions I1a to I4a, I1b to I4b located at one end of the corresponding light guide portions F1a to F4a, F1b to F4b, and F5. , I5, respectively. In the present embodiment, the light from the measurement point 5p is reflected light generated at the measurement point 5p on the measurement surface 5s according to the light emitted by either one of the illumination units E1a and E1b.

Here, of the reflected light from the measurement point 5p, the light incident on the lens C1a is condensed by the lens C1a toward the incident portion I1a of the light guide portion F1a, and the light incident on the lens C1b is reflected by the lens C1b. The light is focused toward the incident portion I1b of the light guide portion F1b. Further, the light incident on the lens C2a is condensed by the lens C2a toward the incident portion I2a of the light guide portion F2a, and the light incident on the lens C2b is directed toward the incident portion I2b of the light guide portion F2b by the lens C2b. Collected. Further, the light incident on the lens C3a is condensed by the lens C3a toward the incident portion I3a of the light guide portion F3a, and the light incident on the lens C3b is directed by the lens C3b toward the incident portion I3b of the light guide portion F3b. Collected. Further, the light incident on the lens C4a is condensed by the lens C4a toward the incident portion I4a of the light guide portion F4a, and the light incident on the lens C4b is directed toward the incident portion I4b of the light guide portion F4b by the lens C4b. Collected. Further, the light incident on the lens C5 is condensed by the lens C5 toward the incident portion I5 of the light guide portion F5.

The light guide portions F1a to F4a, F1b to F4b, and F5 guide the lights respectively received by the lenses C1a to C4a, C1b to C4b, and C5 as light receiving portions to the spectroscopic unit 6. The light guides F6a and F6b guide the light received by the lenses C6a and C6b to the spectroscopic unit 6, respectively. Here, if the light guide portions F1a to F4a, F1b to F4b, F5, F6a, and F6b are configured to include, for example, optical fibers, light guiding can be performed with a simple configuration.

<1.3.2 Spectroscopic unit>
9 and 10 are diagrams schematically illustrating a main configuration of the spectroscopic unit 6. The spectroscopic unit 6 is a part for obtaining information on the spectral distribution of the light guided by the light guides F1a to F4a, F1b to F4b, F5, F6a, and F6b.

As shown in FIGS. 9 and 10, the spectroscopic unit 6 includes a housing 6c, an optical system 6L, a spectroscopic unit 6Lv, and a light detection unit 6Ls. 9 and 10, a part of the housing 6c is drawn, and among the light fluxes of the light emitted from the light guide portions F1a to F4a, F1b to F4b, F5, F6a, and F6b, the light fluxes are extracted. An imaginary line passing through the center of is drawn by a chain line, and the outer edge of the light flux is drawn by a thin line. Further, in FIGS. 9 and 10, the optical axis 6La of the optical system 6L is drawn by a dashed line.

The housing 6c shields incident light from the outside of the spectroscopic unit 6. The housing 6c is provided with openings W1a to W4a, W1b to W4b, W5, W6a, W6b as a plurality of incident parts. In the openings W1a to W4a, W1b to W4b, W5, W6a, W6b, portions near the other ends of the light guide portions F1a to F4a, F1b to F4b, F5, F6a, F6b are arranged, respectively. As a result, in each of the openings W1a to W4a, W1b to W4b, W5, W6a, W6b, light (also referred to as incident light) is transmitted through any of the corresponding light guides F1a to F4a, F1b to F4b, F5, F6a, F6b. Is input to the spectroscopic unit 6.

The light guide portions F1a to F4a, F1b to F4b, F5, F6a, and F6b are the light emitting portions C1a to C4a, C1b to C4b, C5, C6a, and C6b. It has O1b to O4b, O5, O6a, and O6b, respectively. Then, the light is emitted from the emitting portions O1a to O4a, O1b to O4b, O5, O6a, and O6b, so that the light enters the spectroscopic unit 6 through the openings W1a to W4a, W1b to W4b, W5, W6a, and W6b. To be done. Further, imaginary lines obtained by virtually extending the axes in the vicinity of the other ends of the light guide portions F1a to F4a, F1b to F4b, F5, F6a, and F6b respectively indicate the center points of the main surfaces of the optical system 6L. It is set to pass.

The optical system 6L adjusts the shape of the YZ cross section of the luminous flux of the incident light incident from the openings W1a to W4a, W1b to W4b, W5, W6a, and W6b. The optical system 6L has, for example, three cylindrical lenses 6L1 to 6L3. By such an optical system 6L, the YZ cross section of the light flux of the incident light incident from the openings W1a to W4a, W1b to W4b, W5, W6a, W6b is converted into a linear cross section extending in the Y direction. It Accordingly, with a simple configuration, it is possible to achieve the formation of a light beam suitable for the light splitting in the light splitting unit 6Lv and the improvement of the intensity of the light received by the light detection unit 6Ls. As a result, it is possible to improve the S/N ratio in the electric signal obtained by the light detection unit 6Ls.

The spectroscopic unit 6Lv disperses the light having different wavelengths depending on the position in the Y direction to disperse the incident light from the openings W1a to W4a, W1b to W4b, W5, W6a, and W6b.

As the spectroscopic unit 6Lv, for example, a linear variable filter (LVF) or a division filter can be adopted. The LVF is a filter that makes the wavelength of light (also referred to as transmitted light) that passes through the LVF different in proportion to the change in the position where incident light passes in the Y direction (also referred to as wavelength change direction) as one direction. .. The split filter is a filter in which a large number of filters having different wavelengths of light to be transmitted are arranged in the Y direction as one direction.

The light detection unit 6Ls has a plurality of photoelectric conversion elements that respectively obtain electric signals (also referred to as electric signals) according to the intensity of the transmitted light that has passed through the spectroscopic unit 6Lv for each wavelength range. Here, the width of each wavelength range can be set to, for example, about 1 to 10 nm. Here, the plurality of photoelectric conversion elements are arranged at positions different from each other in the direction in which the wavelength of the transmitted light that has passed through the spectroscopic unit 6Lv changes, and the photoelectric conversion elements are arranged in different wavelength ranges of the transmitted light according to the irradiation of the transmitted light. An electric signal corresponding to the intensity is obtained. As a result, information about the spectral distribution of incident light from the openings W1a to W4a, W1b to W4b, W5, W6a, and W6b can be acquired. As the light detection unit 6Ls, for example, a line sensor in which a plurality of photoelectric conversion elements are arranged along the Y direction as one direction can be adopted.

In the light detection unit 6Ls, the plurality of photoelectric conversion elements irradiates the light guided to the light guide unit F6a and transmitted through the spectroscopic unit 6Lv, and the light is guided to the light guide unit F6b and transmitted through the spectroscopic unit 6Lv. An electric signal corresponding to the intensity of each wavelength of each transmitted light is obtained according to the irradiation of light. Thereby, the information regarding the spectral distribution of the light emitted from the illumination units E1a and E1b can be acquired. Therefore, the calculation unit 72, which will be described later, can appropriately perform the correction when calculating the color information related to the measurement surface 5s. As a result, the measurement accuracy of the color information related to the measurement surface 5s can be improved.

FIG. 11 is a YZ plan view schematically illustrating the arrangement of the plurality of openings W1a to W4a, W1b to W4b, W5, W6a, W6b. In this embodiment, the traveling directions of the incident light and the emitted light are +X directions. In the present embodiment, the plurality of openings W6b, W3b, W1b, W2b, W4b, W6a arranged along the Y direction and the plurality of openings W5, W3a, W1a, W2a arranged along the Y direction, W4a is arranged in the Z direction. That is, the plurality of openings W1a to W4a, W1b to W4b, W5, W6a, W6b are arranged in two rows.

Further, the spectroscopic unit 6 has a light shielding portion 6s. The light-shielding portion 6s selectively transmits light traveling from one of the plurality of openings W1a to W4a, W1b to W4b, W5, W6a, and W6b toward the spectroscopic unit 6Lv, and removes light other than the one opening. Residual light traveling from the residual opening toward the spectroscopic unit 6Lv is blocked. Thereby, the light incident from each of the openings W1a to W4a, W1b to W4b, W5, W6a, W6b can be selectively measured. It should be noted that the light-shielding portion 6s is not shown in FIGS. 9 and 10.

FIG. 12 is a front view schematically illustrating the appearance of the light shielding unit 6s. In FIG. 12, a plurality of openings W1a to W4a, W1b to W4b, W5, W6a, W6b and emitting portions O1a to O4a, O1b to O4b, O5, O6a, O6b arranged on the −X side of the light shielding portion 6s. The outer edge of is shown in dashed lines.

As shown in FIG. 12, the light shield 6s has the form of a rotary shutter. Specifically, the light shield 6s has a main body 6sb. The main body portion 6sb may be formed of, for example, a non-translucent disk-shaped thin plate that blocks light. The main body 6sb is provided with windows T1a to T4a, T1b to T4b, T5, T6a, and T6b that allow visible light to pass therethrough. The windows T1a to T4a, T1b to T4b, T5, T6a, and T6b are made of, for example, at least one of a hole (also referred to as a through hole) penetrating the main body 6sb in the X direction and a light-transmitting material. obtain.

In the light-shielding portion 6s, by rotating the main body portion 6sb, light directed from one opening of the plurality of openings W1a to W4a, W1b to W4b, W5, W6a, W6b to the spectroscopic portion 6Lv is transmitted to the window portion T1a to. It selectively passes through T4a, T1b to T4b, T5, T6a, and T6b. At this time, the main body portion 6sb shields the remaining light traveling from the remaining openings other than the one opening toward the spectroscopic section 6Lv. Thus, in the spectroscopic unit 6, the light incident from the openings W1a to W4a, W1b to W4b, W5, W6a, W6b can be selectively measured. From another point of view, by rotating the main body portion 6sb, the light emitted from one of the plurality of emitting portions O1a to O4a, O1b to O4b, O5, O6a, and O6b toward the spectroscopic portion 6Lv is converted into the window portion. It selectively passes through T1a to T4a, T1b to T4b, T5, T6a, and T6b. At this time, the main body portion 6sb shields the remaining light from the remaining emitting portions other than the one emitting portion toward the spectroscopic portion 6Lv. Thereby, in the spectroscopic unit 6, the light emitted from each of the emission units O1a to O4a, O1b to O4b, O5, O6a, O6b can be selectively measured with a simple configuration.

In the present embodiment, the drive unit (not shown) rotates the main body 6sb around the virtual rotation shaft 6sa. Here, the virtual rotation shaft 6sa penetrates the center of the circular board surface of the main body portion 6sb in the X direction.

As shown in FIG. 12, when the main body portion 6sb is viewed in a plane from the +X side in the −X direction, the main body portion 6sb has 11 windows T6b, T5, T3b, T3a, T1b, and T1a in the clockwise direction. , T2b, T2a, T4b, T4a, T6a are provided in this order. Then, for example, when obtaining the color information of the measurement surface 5s, the main body portion 6sb is rotated clockwise about the rotation axis 6sa, and the openings W4a, W4b, W2a, W2b, W1a, W1b, W3a, W3b, W5 are provided. The light traveling from the light source to the spectroscopic unit 6Lv selectively passes through the light shielding unit 6s in this order. That is, the openings W4a, W4b, W2a, W2b, W1a, W1b, W3a, W3b, and W5 are set in this order to a state where they are not shielded from light (also referred to as a non-shielded state). From another point of view, at this time, the light traveling from the emitting portions O4a, O4b, O2a, O2b, O1a, O1b, O3a, O3b, O5 toward the spectroscopic portion 6Lv selectively passes through the light shielding portion 6s in this order. That is, the emitting portions O4a, O4b, O2a, O2b, O1a, O1b, O3a, O3b, and O5 are set to the non-light-shielding state in which they are not alternately shielded in this order.

A plurality of light guide portions F1a to F4a, F1b to F4b, F5, F6a, F6b and a light shielding portion 6s, each of which receives light with lenses C1a to C4a, C1b to C4b, C5, C6a, C6b as a light receiving portion. The functional unit that selectively guides the light of 1 to the detection position (the position where the light detection unit 6Ls is arranged) in a specific order is also referred to as a selective light guide unit.

<1.3.3 Control unit, storage unit and operation display unit>
The control unit 7 is a unit that controls the operation of the multi-angle colorimeter 1 and performs various calculations. The control unit 7 has, for example, a central processing unit (CPU), a memory, and the like, and realizes various functions by reading and executing a program stored in the storage unit 8. The control unit 7 includes, for example, a measurement control unit 71 and a calculation unit 72 as a functional configuration realized by the control unit 7.

The measurement control unit 71 controls the irradiation of light from the illumination units E1a and E1b to the measurement point 5p by transmitting an electric signal to the light emitting circuits Ct1a and Ct1b, for example. Further, the measurement control unit 71 controls the rotation of the light shielding unit 6s, for example, by transmitting a signal to a drive unit (not shown).

The calculation unit 72 obtains the color information of the measurement surface 5s arranged at the measurement point 5p based on the plurality of electric signals obtained by the light detection unit 6Ls. For example, in the calculation unit 72, based on the electric signal obtained by the light detection unit 6Ls, detection relating to the reflected light from the measurement surface 5s illuminated by the illumination unit E1a to each of the lenses C1a to C4a, C5, C1b to C4b. Each value (also called light detection value) is obtained. Here, as the light detection value, for example, a spectral distribution can be adopted. Then, the calculation unit 72 obtains color information (for example, tristimulus value) of the measurement surface 5s existing at the measurement point 5p based on the plurality of light detection values. As a result, in the multi-angle colorimeter 1, simplification of the configuration and improvement in acquisition accuracy of color information regarding the measurement surface 5s located at the measurement point 5p can be achieved.

The storage unit 8 is composed of, for example, a non-volatile storage medium, and stores programs and various data.

The operation display unit 9 has an operation unit 91 and a display unit 92. The operation display unit 9 transmits a signal according to the operation of the operation unit 91 to the control unit 7, so that the color measurement operation of the multi-angle colorimeter 1 under the control of the control unit 7 can be executed. The operation display unit 9 also obtains data relating to the color information as the measurement result obtained by the calculation unit 72, and visually outputs various information including the color information on the display unit 92.

<1.4 Multi-angle colorimeter operation>
<1.4.1 Acquire light detection value by actual measurement>
13 to 15 are flowcharts showing a flow when the light detection value is actually measured. This flow can be realized by the control of the measurement control unit 71. Various information obtained during the actual measurement is appropriately stored in the memory or the like.

First, in step S0 of FIG. 13, the opening W6a and the emission unit O6a are set to the non-light-shielding state, the illumination unit E1a is turned on, and the photodetection unit 6Ls and the calculation unit 72 move from the opening W6a to the spectroscopic unit 6. The light detection value (also referred to as the first reference light detection value) of the incident light (that is, the emission light emitted from the emission unit O6a) is acquired.

In step S1, the opening W4a and the emitting portion O4a are set in the non-light-shielding state.

In step S2, the measurement surface 5s is illuminated by the illumination unit E1b, and the light detection unit 6Ls and the calculation unit 72 convert the incident light into the spectroscopic unit 6 from the opening W4a (that is, the emission light emitted from the emission unit O4a). The first detected light value is acquired.

In step S3, the opening W4b and the emitting portion O4b are set in the non-light-shielding state.

In step S4, the illuminating section E1a illuminates the measurement surface 5s, and the light detecting section 6Ls and the computing section 72 convert the incident light into the spectroscopic unit 6 from the opening W4b (that is, the outgoing light emitted from the outgoing section O4b). The second detected light value is acquired.

In step S5, the opening W2a and the emitting portion O2a are set to the non-light-shielding state.

In step S6, the measurement surface 5s is illuminated by the illumination unit E1a, and the light detection unit 6Ls and the calculation unit 72 convert the incident light into the spectroscopic unit 6 from the opening W2a (that is, the emission light emitted from the emission unit O2a). The third detected light value is acquired.

In step S7, the measurement surface 5s is illuminated by the illumination unit E1b, and the light detection unit 6Ls and the calculation unit 72 convert the incident light from the opening W2a into the spectroscopic unit 6 (that is, the emission light emitted from the emission unit O2a). The fourth detected light value is acquired.

Next, in step S8 of FIG. 14, the opening W2b and the emitting portion O2b are set to the non-light-shielding state.

In step S9, the illuminating section E1a illuminates the measurement surface 5s, and the light detecting section 6Ls and the calculating section 72 convert the incident light into the spectroscopic unit 6 from the opening W2b (that is, the outgoing light emitted from the outgoing section O2b). The fifth detected light value is acquired.

In step S10, the measurement surface 5s is illuminated by the illumination unit E1b, and the light detection unit 6Ls and the calculation unit 72 convert the incident light into the spectroscopic unit 6 from the opening W2b (that is, the emission light emitted from the emission unit O2b). The sixth light detection value is acquired.

In step S11, the opening W1a and the emitting portion O1a are set in the non-light-shielding state.

In step S12, the illuminating section E1a illuminates the measurement surface 5s, and the light detecting section 6Ls and the calculating section 72 convert the incident light into the spectroscopic unit 6 from the opening W1a (that is, the outgoing light emitted from the outgoing section O1a). The seventh detected light value is acquired.

In step S13, the opening W1b and the emitting portion O1b are set in the non-light-shielding state.

In step S14, the illuminating section E1b illuminates the measurement surface 5s, and the light detecting section 6Ls and the calculating section 72 convert the incident light into the spectroscopic unit 6 from the opening W1b (that is, the outgoing light emitted from the outgoing section O1b). The eighth detected light value is acquired.

Next, in step S15 of FIG. 15, the opening W3a and the emitting portion O3a are set to the non-light-shielding state.

In step S16, the measurement surface 5s is illuminated by the illumination unit E1a, and the light detection unit 6Ls and the calculation unit 72 convert the incident light from the opening W3a into the spectroscopic unit 6 (that is, the emission light emitted from the emission unit O3a). The ninth light detection value is acquired.

In step S17, the illumination surface E1b illuminates the measurement surface 5s, and the light detection unit 6Ls and the calculation unit 72 convert the incident light into the spectroscopic unit 6 from the opening W3a (that is, the emission light emitted from the emission unit O3a). The 10th light detection value concerned is acquired.

In step S18, the opening W3b and the emitting portion O3b are set in the non-light-shielding state.

In step S19, the illuminating section E1a illuminates the measurement surface 5s, and the light detecting section 6Ls and the calculating section 72 convert the incident light into the spectroscopic unit 6 from the opening W3b (that is, the outgoing light emitted from the outgoing section O3b). The 11th light detection value concerned is acquired.

In step S20, the illumination surface E1b illuminates the measurement surface 5s, and the photodetector 6Ls and the calculator 72 convert the incident light into the spectroscopic unit 6 from the opening W3b (that is, the emitted light emitted from the emitting portion O3b). The twelfth light detection value is acquired.

In step S21, the opening W5 and the emitting portion O5 are set in the non-light-shielding state.

In step S22, the measurement surface 5s is illuminated by the illumination unit E1a, and the light detection unit 6Ls and the calculation unit 72 convert the incident light from the opening W5 into the spectroscopic unit 6 (that is, the emission light emitted from the emission unit O5). The thirteenth light detection value is acquired.

In step S23, the measurement surface 5s is illuminated by the illumination unit E1b, and the light detection unit 6Ls and the calculation unit 72 convert the incident light into the spectroscopic unit 6 from the opening W5 (that is, the emission light emitted from the emission unit O5). The 14th light detection value concerned is acquired.

In step S24, the opening W6b and the emitting portion O6b are set to the non-light-shielding state, the illumination unit E1b is turned on, and the incident light from the opening W6b to the spectroscopic unit 6 (that is, the light detecting unit 6Ls and the calculating unit 72 is turned on). , The light detection value (also referred to as the second reference light detection value) of the emission light emitted from the emission unit O6b is acquired.

<1.4.2 Acquisition of light detection value by estimation>
In the present embodiment, based on the detection result of at least two lights of the plurality of lights having different reflection angles, the detection result of the specific light having a reflection angle different from that of the at least two lights of the reflected lights is estimated. In the following, as an example, of the reflected light emitted from the illumination unit E1a, based on the detection result of the light with an aspecular angle of 105 degrees and the detection result of the light with an aspecular angle of 115 degrees, the specific light of the aspecular angle of 110 degrees The case where the detection result of 1 is estimated will be described.

Here, an angle inclined by X degrees (0≦X≦180) in the direction approaching the reference plane from the regular reflection direction of the light irradiated to the measurement point 5p is expressed as an aspecular angle X degree, and from the regular reflection direction. An angle in a direction inclined by X degrees (0≦X≦180) in a direction away from the reference plane is expressed as an aspecular angle−X degrees. Further, hereinafter, the aspecular angle is referred to as the as angle.

The direction of an imaginary line connecting the illuminating section E1a and the measurement point 5p is a direction inclined 45 degrees clockwise from the central axis 2n in the drawing view of FIG. Therefore, the specular reflection direction of the light emitted from the illumination unit E1a to the measurement point 5p is a direction inclined by 45 degrees counterclockwise from the central axis 2n in the drawing view of FIG. 7.

The direction of an imaginary line connecting the lens C2a and the measurement point 5p is a direction tilted clockwise by 60 degrees from the central axis 2n in the drawing view of FIG. Therefore, the light received by the lens C2a is expressed as light having an as angle of 105 degrees when viewed from the illumination section E1a. Further, the direction of the imaginary line connecting the lens C1a and the measurement point 5p is a direction inclined by 70 degrees clockwise from the central axis 2n in the drawing view of FIG. Therefore, the light received by the lens C1a is expressed as light having an as angle of 115 degrees when viewed from the illumination section E1a. Therefore, the detection result of the light having the as angle of 105 degrees specifically means the third light detection value acquired in step S6. Further, the light having an as angle of 115 degrees specifically means the seventh light detection value acquired in step S12.

FIG. 16 is a diagram showing the relationship between the as angle and the reflectance in Silver Metallic as an example of the DUT 5. In FIG. 16, the vertical axis represents the light reflectance (value obtained by multiplying the ratio of the emitted light flux to the perfect diffuse reflection surface by 100) in the range of 0% to 500%, and the horizontal axis represents the as angle −30 degrees. Shows the as angle in the range from to 120 degrees.

As shown in FIG. 16, the light reflectance has a peak at an as angle of 0 degrees (angle in the regular reflection direction), and monotonically decreases as the distance from the as angle of 0 degrees increases. Further, as shown in FIG. 16, in a range where the absolute value of the as angle is relatively large, for example, in a range where the absolute value of the as angle is 70 degrees to 180 degrees, the reflectance value is expressed in a more linear form. It

Therefore, the light reflectance at an as angle of 110 degrees, which is located at the midpoint between the as angle of 105 degrees and the as angle of 115 degrees, is the light reflectance at the as angle of 105 degrees and the light reflectance at the as angle of 115 degrees. It is approximately obtained by averaging. In addition, since the light detection value acquired by the light detection unit 6Ls is a value corresponding to the emitted light flux, in the present embodiment in which the incident light flux from the incidence unit I1a is constant, the light detection value of light at an as angle of 110 degrees. Is approximately obtained by averaging the light detection value of light at the as angle of 105 degrees (third light detection value) and the light detection value of light at the as angle of 115 degrees (seventh light detection value).

Since the third light detection value has already been acquired in step S6 and the seventh light detection value has already been acquired in step S12, the as angle of the light emitted from the illumination unit E1a is based on these detection values. The light detection value (15th light detection value) of light at 110 degrees is estimated. In addition, the light detection value (sixteenth light detection value) of the light emitted from the illumination unit E1b at the as angle of 110 degrees is also estimated based on the sixth light detection value and the eighth light detection value, similarly to the above. To be done. These estimations are executed by the calculation unit 72.

<1.4.3 Obtain color information of measurement surface 5s>
Based on the 1st to 14th light detection values acquired by actual measurement, the 15th and 16th light detection values acquired by estimation, and the 1st and 2nd reference light detection values acquired in steps S0 and S24, the calculation unit 72 calculates color information. Here, an average value of the following pairs of light detection values [i] to [viii] is calculated as the corrected light detection value for each angle. Then, based on the plurality of corrected light detection values and the first and second reference light detection values, color information (for example, tristimulus value) of the measurement surface 5s existing at the measurement point 5p is obtained, and the multi-angle measurement is performed. The color measurement operation of the color meter 1 is completed.

[I] a combination of a first light detection value and a second light detection value,
[Ii] a combination of a third light detection value and a sixth light detection value,
[Iii] a combination of a fourth light detection value and a fifth light detection value,
[Iv] a combination of a seventh light detection value and an eighth light detection value,
[V] A combination of a ninth light detection value and a twelfth light detection value,
[Vi] A combination of the tenth light detection value and the eleventh light detection value,
[Vii] A combination of the thirteenth light detection value and the fourteenth light detection value,
[Viii] A combination of the 15th light detection value and the 16th light detection value.

In the operation flow, for example, the obtained color information may be displayed on the display unit 92 as the measurement result under the control of the measurement control unit 71.

<1.5 Summary>
As described above, in the multi-angle colorimeter 1 according to the present embodiment, based on the detection result of at least two lights of a plurality of lights having different reflection angles, the reflected light is reflected from the at least two lights. The detection results of specific lights with different angles are estimated. As a result, the light detection value at an as angle of 110 degrees in which the optical elements (lenses, light guides, etc.) for guiding light are not actually arranged are the light detection value at the as angle of 105 degrees and the as detection value. It is estimated and acquired based on the light detection value at an angle of 115 degrees. As described above, since the multi-angle colorimeter 1 can obtain the light detection value even at an angle without each optical element, the layout of each member arranged in the multi-angle colorimeter 1 can be improved. The degree of freedom is improved. As a result, the multi-angle colorimeter 1 of the present embodiment can be made smaller than the conventional multi-angle colorimeter in which each optical element for guiding light is arranged at an angular position where a light detection value is desired to be acquired. .. Further, in the present embodiment, in order to improve the degree of freedom of layout and downsize the multi-angle colorimeter 1, another mode for downsizing the multi-angle colorimeter by reducing the effective diameter of the lens or the like. Unlike the above, it is possible to suppress a decrease in color measurement accuracy.

Generally, the double-pass multi-angle colorimeter has the above-mentioned advantage that the measurement error due to the attitude error of the multi-angle colorimeter is reduced. On the other hand, the double-pass multi-angle colorimeter has a low degree of freedom in the layout of each member due to the large number of each member arranged in the multi-angle colorimeter (therefore, the multi-angle colorimeter). However, it has a drawback that it becomes large. Since the multi-angle colorimeter 1 of the present embodiment can realize the degree of freedom in layout and the downsizing of the apparatus by using the above estimation technique, it is possible to obtain the advantages of the double-pass method while compensating for the drawbacks of the double-pass method. Can be desirable.

In the present embodiment, first, the light detection value at the as angle of 105 degrees and the light detection value at the as angle of 115 degrees are acquired by actual measurement, and then the light detection value of the specific light at the as angle of 110 degrees is acquired by estimation. As a result, the light detection values of the as angle of 105 degrees, the as angle of 110 degrees, and the as angle of 115 degrees are acquired. Here, it is assumed that the multi-angle colorimeter according to the comparative example of the present embodiment is a multi-angle colorimeter that obtains all of these three light detection values by actual measurement. In this multi-angle colorimeter, there are three optical positions for guiding light, a position corresponding to an as angle of 105 degrees, a position corresponding to an as angle of 110 degrees, and a position corresponding to an as angle of 115 degrees. It becomes necessary to arrange elements. However, in the case where the optical elements are arranged at the angular intervals of 5 degrees as described above, if the size of each optical element is the same as that of this embodiment, the multi-angle colorimeter becomes large. Is not desirable. Further, when the optical elements are arranged at an angle interval of 5 degrees, if the size of each optical element is smaller than that of this embodiment (for example, the effective diameter of the lens is small), the multi-angle colorimeter The colorimetric accuracy of is reduced, which is not desirable. Therefore, by using the above-described estimation technique at a portion where the angle interval between adjacent light receiving elements is small (for example, a portion of 5 degrees or less) as in the present embodiment, the size of the apparatus and the color measurement accuracy are reduced. It can be effectively suppressed.

<2 modification>
It should be noted that the present invention is not limited to the above embodiment, and various modifications and improvements can be made without departing from the gist of the present invention.

<2.1 Modification of estimation technology>
In the above-described embodiment, the light detection values (third light detection value and seventh light detection value) for two lights having different angles are known, and the light detection value of the specific light is generated as estimated information based on these. However, the present invention is not limited to this. If the reflectances of two lights with different angles are known, the reflectance of the specific light may be generated as the estimation information based on these. Also, other index values may be generated as the estimation information.

In the above-described embodiment, a calculation process for averaging the light detection value (third light detection value) of light at an as angle of 105 degrees and the light detection value (seventh light detection value) of light at an as angle of 115 degrees is performed. , A light detection value of light at an as angle of 110 degrees was approximately obtained. The arithmetic processing may be a mode including weighting processing according to each reflection angle of at least two lights and the reflectance of the target surface. For example, in the example of the above-described embodiment, the light detection value of light at an as angle of 110 degrees is calculated by the sum of the value obtained by multiplying the third light detection value by the coefficient n1 and the value obtained by multiplying the seventh light detection value by the coefficient n2. It may be obtained approximately. Further, in the above-described embodiment, the arithmetic processing is executed by using the fact that the reflectance can be approximately expressed by a linear function having the as angle as an independent variable, but the present invention is not limited to this. When the reflectance can be approximately expressed by a Gaussian function in which the as angle is an independent variable, the coefficients n1 and n2 can be appropriately set according to the relationship between the reflectance and the as angle. The effective diameters of the lenses C1a to C4a, C1b to C4b, C5, C6a, and C6b can be set appropriately. For example, in an aspect in which the estimation technique is used based on the detection results of two lights having different as angles, measurement is performed by reducing the effective diameter with a lens arranged at an angle with a small as angle (angle near 0 degree as angle). The possibility that the lens receives the specularly reflected light on the surface 5s can be reduced, which is desirable. In this case, the coefficients n1 and n2 are appropriately set in consideration of the effective diameter of each lens.

When the calculation process includes the weighting process as described above, the reflection angle of the specific light falls within the reflection angle range sandwiched between the maximum angle and the minimum angle of the reflection angles of at least two lights that are the basis of the estimation. In the included mode, the approximation accuracy is improved as compared with the mode in which the reflection angle of the specific light is not included in this angle range, which is desirable. Particularly, in a mode in which the reflection angle of the specific light is included in this angle range and the regular reflection angle (as angle 0 degree) is not included in this angle range, the sum of the coefficients n1 and n2 is 1. An approximation can be used.

In the above-described embodiment, a mode has been described in which the estimated information of the specific light is generated based on the two lights including the light at the as angle of 105 degrees and the light at the as angle of 115 degrees, but the present invention is not limited to this. There may be three or more lights that are the basis of estimation, and there may be a plurality of specific lights.

In the above-described embodiment, the light detection unit individually detects each of the two lights serving as the basis of the estimation, and the arithmetic processing is performed based on the detection result of each of the two lights, thereby responding to the specific light. Although the mode in which the estimated information is generated has been described, the present invention is not limited to this. There may be a mode in which the estimated information is generated by at least two lights being optically mixed and detected by the photodetector.

17 to 20 are schematic diagrams showing the peripheral portions of the lenses C1a and C2a in the multi-angle colorimeter using this optical mixing. In FIGS. 17 to 20, among the respective components of the spectroscopic unit, the photodetector is shown in particular.

As a first example of the optical mixing, there may be a mode in which the light detection unit 6Ls simultaneously detects the light guided to the light guide unit F1a and the light guided to the light guide unit F2a ( (Fig. 17). In this case, the spectroscopic unit 6W has a light blocking portion (not shown) that allows these two lights to pass through at the same time.

In addition, as a second example of optical mixing, the light received by the lens C1a and the light received by the lens C2a are incident on each of the entrances of the bundle fiber BF having two entrances and one exit. It is also possible to adopt a mode in which the light detectors 6Ls that are respectively incident are optically mixed in the middle of the path of the bundle fiber BF and are emitted from the emission port (FIG. 18). In this case, the spectroscopic unit 6X has a light blocking portion (not shown) that allows the light guided to the bundle fiber BF to pass therethrough.

Further, as a third example of optical mixing, the light detection unit 6Ls may detect diffused light (light in which two lights serving as a basis for estimation are diffused through the diffuser plate 6D). (FIG. 19). In this case, the spectroscopic unit 6Y diffuses the two light beams that pass through both the light guided to the light guide portion F1a and the light guided to the light guide portion F2a, and a light blocking portion (not shown). And a diffusing plate 6D.

Further, as a fourth example of optical mixing, the light detection unit 6Ls passes through the neutral density filter ND1 and is guided to the light guide unit F1a, and the light detection unit 6Ls passes through the neutral density filter ND2 and the light guide unit F2a. It is also possible to adopt a mode in which each of the light guided to and the detection of the light is simultaneously performed (FIG. 20). In this case, the spectroscopic unit 6Z has a light blocking portion (not shown) that simultaneously passes both the light guided to the light guide portion F1a and the light guided to the light guide portion F2a. In the fourth example of optical mixing, if the transmittances of the neutral density filters ND1 and ND2 are preset according to the reflection angles of the two lights and the reflectance of the target surface, the weighting process is included. The same effect as when the estimated information is generated by the arithmetic processing can be obtained.

<2.2 other modifications>
In the above-described embodiment, the multi-angle colorimeter 1 in which the pair of light emitting/receiving units are symmetrically arranged with respect to the reference plane is adopted, but the estimation technique of the present invention does not adopt the double pass method. It can also be applied to multi-angle colorimeters. FIG. 21 is a schematic view illustrating the main configuration of the multi-angle colorimeter 1A according to the modification. As shown in FIG. 21, the multi-angle colorimeter 1A is a one-way illumination-multi-direction light receiving type colorimeter, and the multi-angle colorimeter 1A does not employ the double-pass type. Also in this aspect, similar to the case of the above-described embodiment, based on the detection result of at least two lights detected by the spectroscopic unit 6A, the detection of the specific light having a reflection angle different from that of the at least two lights among the reflected lights. Estimated information is generated that estimates the result. This improves the degree of freedom in the layout of the members inside the colorimeter.

Further, in the above-described embodiment, the total number of light receiving portions and reference light receiving portions, the number of light guiding portions, the number of openings, and the number of emitting portions are 11, respectively, but the number is not limited to this. The total number of light receiving portions and reference light receiving portions, the number of light guiding portions, the number of openings, and the number of emitting portions may be two or more, respectively.

Moreover, in the said embodiment, although the two illumination parts E1a and E1b each had a light source, it is not restricted to this. A configuration capable of irradiating the light emitted from one light source toward the measurement point 5p from two or more positions by an optical fiber or the like may be adopted. In this case, it is possible to adopt a mode in which the irradiation of light from two or more positions toward the measurement point 5p is alternatively executed by, for example, the movement of the light shielding unit.

Needless to say, all or part of the configurations of the above-described embodiment and various modifications can be combined as appropriate within a range that does not contradict.

1,1A Multi-angle colorimeter 2n Central axis 5 Object to be measured 5n Normal 5p Measuring point 5s Measuring surface 6,6A, 6X, 6Y, 6Z Spectroscopic unit 6D Diffuser 6Ls Photodetector 7 Controller 8 Memory 10, 10A Light emitting/receiving unit 71 Measurement control unit 72 Calculation unit BF Bundle fiber C1a to C4a, C1b to C4b, C5, C6a, C6b Lens E1, E1a, E1b, E2 Illumination unit F1a to F4a, F1b to F4b, F5, F6a, F6b Light guide part L1a, L1b Illumination unit O1a-O4a, O1b-O4b, O5, O6a, O6b Emission part T1a-T4a, T1b-T4b, T5, T6a, T6b Window part W1a-W4a, W1b-W4b, W5, W6a, W6b opening

Claims (8)

An illumination unit that emits light toward a measurement point on the target surface,
A plurality of light receiving portions that receive reflected light from the measurement point of the light at a plurality of different reflection angles, and
A selective light guide part that selectively guides the remaining light except at least two lights of the plurality of lights received by the plurality of light receivers to a detection position in a specific order;
A photodetector arranged at the detection position and photoelectrically converting light emitted from the selective light guide,
Equipped with
Before even without Kisukuna based on the detection results of the two optical, estimation information said at least two optical estimating the detection result of the different specific light reflection angle of the reflected light is generated,
By pre-Symbol least two light is detected by the light detecting portion are mixed optically, multi-angle colorimeter that wherein the estimation information is generated. The multi-angle colorimeter according to claim 1,
Wherein the specular reflection direction or RaHajime reference plane approaching direction X degrees (0 ≦ X ≦ 180) inclined at a direction angle of the illumination light irradiated to the measurement point is expressed as aspecular angle X degrees, the specular direction When the angle in the direction inclined by X degrees (0≦X≦180) in the direction away from the reference plane is expressed as aspecular angle −X degrees,
By the aspecular angle of the plurality of light is detected at a different at least two light are mixed optically the light detecting unit, wherein the estimation information is generated,
The reference surface is a multi-angle colorimeter, wherein a plane der Rukoto including a virtual central axis intersects the measuring surface as the target surface at the measurement point. The multi-angle colorimeter according to claim 1 or 2,
The selective light guide has a bundle fiber having a plurality of entrances and a single exit,
A multi-angle colorimeter, wherein the at least two lights are optically mixed in the path of the bundle fiber and detected by the photodetector. The multi-angle colorimeter according to any one of claims 1 to 3,
At least two filters provided in the middle of each optical path of the at least two lights and having transmissivities corresponding to the respective reflection angles of the at least two lights and the reflectivity of the target surface;
A multi-angle colorimeter characterized by comprising. The multi-angle colorimeter according to any one of claims 1 to 4,
A multi-angle colorimeter, wherein a reflection angle of the specific light is included in an angle range sandwiched between a maximum angle and a minimum angle of the reflection angles of the at least two lights. A plurality of illumination units that are symmetrically arranged with respect to a reference plane that is a plane that includes a virtual central axis that intersects the measurement surface at the measurement point, and that irradiates light toward the measurement point.
A plurality of light receiving portions that are symmetrically arranged with respect to the reference plane and that receive reflected light from the measurement points at mutually different reflection angles,
A selective light guide part that selectively guides the remaining light except at least two lights of the plurality of lights received by the plurality of light receivers to a detection position in a specific order;
A photodetector arranged at the detection position and photoelectrically converting light emitted from the selective light guide,
Equipped with
In both the viewed from the reference plane on one side and the other side on the basis of the detection result even before Kisukuna no two light are obtained is guided to the light detector, said one of said reflected light at least The estimation information for estimating the detection result of the specific light having a different reflection angle from the two lights is generated,
By pre-Symbol least two light is detected by the light detecting portion are mixed optically, multi-angle colorimeter that wherein the estimation information is generated. The multi-angle colorimeter according to claim 6,
An angle in a direction inclined by X degrees (0≦X≦180) from the regular reflection direction of the illumination light irradiated to the measurement point toward the reference plane is expressed as an aspecular angle X degree, and from the regular reflection direction. When an angle in a direction inclined by X degrees (0≦X≦180) in a direction away from the reference plane is expressed as an aspecular angle−X degrees,
By the aspecular angle of the plurality of light is detected at a different at least two light are mixed optically the light detecting unit, measuring multi-angle, wherein the estimation information is generated Colorimeter. The multi-angle colorimeter according to claim 6,
On both the one side and the other side, an angle of a direction inclined by X degrees (0≦X≦180) in a direction approaching the reference plane from a regular reflection direction of the illumination light applied to the measurement point is aspecular. When expressed as an angle X degrees, and an angle inclined by X degrees (0≦X≦180) from the regular reflection direction in a direction away from the reference surface is expressed as an aspecular angle−X degrees,
On both the one side and the other side, the at least two lights are composed of light having an aspecular angle of 105 degrees and light of an aspecular angle of 115 degrees, and the specific light is composed of light having an aspecular angle of 110 degrees. This is a multi-angle colorimeter.

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