WO2011158540A1

WO2011158540A1 - Color sensor

Info

Publication number: WO2011158540A1
Application number: PCT/JP2011/056735
Authority: WO
Inventors: 明弘細谷
Original assignee: オムロン株式会社
Priority date: 2010-06-18
Filing date: 2011-03-22
Publication date: 2011-12-22
Also published as: JP2012002762A

Abstract

Provided is a color sensor which can be used, with a reduced number of light sources, for a multi-directional illumination and unidirectional light-receiving colorimeter. To this end, a curved reflection mirror (15) is disposed to be focused on the emission point of a light source (13), and an optical path separating means (16) having two plane mirrors (16a, 16b) is disposed in the direction of a beam of light emitted from the light source (13), the beam having been collimated by the curved reflection mirror (15). The collimated beam reflected on the plane mirror (16a) illuminates directly a surface to be measured, while the collimated beam reflected on the plane mirror (16b) is reflected on an illuminating reflection mirror (17) to then illuminate in a different direction the surface to be measured.

Description

Color sensor

The present invention relates to a color sensor. Specifically, the present invention relates to a color sensor used as an illumination optical system of a colorimeter, for example.

Colorimeters are used to inspect the color of printed matter printed on printing presses and the painted surface of industrial products. The colorimeter includes a multi-angle illumination multi-directional colorimeter that illuminates from multiple directions and receives light in one direction, and a unidirectional illumination multi-directional light reception that illuminates from one direction and receives light in multiple directions. There is a multi-angle colorimeter of the type. Of these, the multi-directional illumination unidirectional light-receiving colorimeter irradiates the surface to be measured from multiple directions and receives the reflected light, so that the illumination light from each direction can be averaged and received. Since it becomes difficult to be influenced by the material of the target surface, measurement of the measurement target surface having various reflectance characteristics is possible, and the reproducibility of the measurement result is improved.

There is one disclosed in Patent Document 1 as a multi-directional illumination unidirectional light-receiving colorimeter. In the colorimeter disclosed in Patent Document 1, a plurality of light sources are arranged along a focus circumference (focus group) located on the inner surface side of the toroidal mirror. Each light source is arranged so as to emit light toward the toroidal mirror, and the light emitted from each light source is collimated by being reflected by the toroidal mirror, and reflected by the toroidal mirror and returned to the parallel light. A light beam is irradiated onto the surface to be measured. As a result, the parallel light flux emitted from each light source is irradiated onto the measurement target surface at different angles. Then, the light reflected by the measurement target surface is received by the light receiving unit, and a colorimetric inspection is performed.

JP 2006-145373 A

However, in the colorimeter as disclosed in Patent Document 1, the same number of light sources as the direction of the light rays irradiated on the measurement target surface are required. Therefore, a large number of light sources are required as a whole, and there is a problem that the manufacturing cost of the colorimeter is high.

Further, in the colorimeter of Patent Document 1, light emitted from the light source is reflected by the toroidal mirror and returned, so that a light source shadow is generated on the light irradiated on the measurement target surface. In order to reduce the shadow, it is necessary to make the light source as small as possible. If a smaller light source is used, the manufacturing cost of the colorimeter is increased.

The present invention has been made in view of the technical problems as described above. The purpose of the present invention is to provide the number of light sources to be used as long as the number of light directions irradiated to the measurement target surface is the same. It is an object of the present invention to provide a color sensor that can reduce the amount of color.

The color sensor according to the present invention includes one or a plurality of light sources, a curved reflector that converts light emitted from the light sources into non-diffused light, and an optical path that separates the optical path of the non-diffused light into different optical paths. A separation unit; and an irradiating reflecting mirror that reflects the light of a part of the plurality of optical paths separated by the optical path separating unit, the non-diffused light reflected by the irradiating reflecting mirror being measured surface A non-diffused light of a light path other than the part of the plurality of light paths separated by the light path separating means from a direction different from that of the non-diffused light reflected by the irradiation reflecting mirror It is characterized by irradiating the surface.

In the color sensor of the present invention, the light emitted from the light source is divided into light of a plurality of optical paths by the optical path separation means, and the light divided into the plurality of optical paths is irradiated to the measurement target surface from different directions, so one light source The surface to be measured can be irradiated from a plurality of directions. Therefore, the number of necessary light sources can be reduced as compared with the number of light beam directions irradiated to the measurement target surface, and the manufacturing cost of the color sensor can be reduced.

Further, in this color sensor, since the measurement target surface is irradiated with non-diffused light (that is, parallel light or focused light), the vicinity of the measurement target surface is compared with the case where the measurement target surface is irradiated with diffused light. It becomes difficult to irradiate the member (for example, the casing of the colorimeter). For this reason, it is difficult for the light receiving unit to receive light reflected from a surface other than the measurement target surface, noise is reduced, and the sensitivity of the colorimeter is improved.

In an embodiment of the color sensor according to the present invention, the curved reflecting mirror is a parabolic mirror whose mirror surface forms a part of a rotating paraboloid, and the focal point of the rotating paraboloid is a light emitting point of the light source. It is characterized by being arranged so as to match. According to this embodiment, the light emitted from the light source can be converted into parallel light by being reflected by the curved reflecting mirror, which is a parabolic mirror.

In addition, when the curved reflector does not include a region near the apex of the paraboloid of revolution, a light source shadow does not occur in the parallel light converted by the curved reflector, so the light use efficiency of the light source is good. become.

Also, in another embodiment of the color sensor according to the present invention, various forms of optical path separation means can be considered. For example, if a plurality of plane mirrors are used as the optical path separating means, the non-diffused light converted by the curved reflecting mirror is reflected in a plurality of directions to separate the optical path of the non-diffused light into a plurality of different optical paths. Can do. Further, if the light separating means is arranged so as to block and reflect a part of the non-diffused light converted by the curved reflecting mirror using, for example, a plane mirror, the optical path of the non-diffused light is separated into a plurality of different optical paths. be able to. Further, if a half mirror is used as the light separating means, a part of the non-diffused light converted by the curved reflector is transmitted, and the remaining non-diffused light is reflected by reflecting the remaining non-diffused light. Can be separated into a plurality of different optical paths.

In still another embodiment of the color sensor according to the present invention, the measurement object surface is irradiated with non-diffused light from different directions at the same angle with respect to the direction perpendicular to the measurement object surface. According to this embodiment, the direction dependency of the colorimeter can be reduced, and the same measurement result can be obtained regardless of the orientation.

Still another embodiment of the color sensor according to the present invention is characterized in that the curved reflecting mirror and the irradiation reflecting mirror are integrally formed. According to this embodiment, since the number of parts is reduced, the cost of the color sensor is reduced, and the position adjustment during assembly is facilitated.

Still another embodiment of the color sensor according to the present invention includes a plurality of light sources and a set of curved reflectors, optical path separating means, and irradiation reflectors corresponding to each of the plurality of light sources. It is characterized by. According to this embodiment, it is possible to irradiate non-diffused light onto the measurement target surface from more directions.

In addition, when a plurality of sets of illumination optical systems including a light source, a curved reflector, a light separating means, and an illumination reflector are provided, and the illumination optical system is arranged around a central axis perpendicular to the measurement target surface The direction dependency of the colorimeter can be further reduced, and the same measurement result can be obtained regardless of the direction.

Further, the non-diffused light reflected and emitted by the curved reflecting mirror is not limited to parallel light, and may be converged light that is gently focused.

The means for solving the above-described problems in the present invention has a feature in which the above-described constituent elements are appropriately combined, and the present invention enables many variations by combining such constituent elements. .

FIG. 1 is a schematic cross-sectional view of a color sensor according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of a parabolic mirror (off-axis parabolic mirror). FIG. 3 is an explanatory diagram of the color sensor according to the first embodiment. FIG. 4 is an explanatory diagram of the color sensor according to the first embodiment. FIG. 5 is a plan view of a color sensor according to Embodiment 2 of the present invention. FIG. 6 is a schematic perspective view illustrating light emitted from the color sensor according to the second embodiment to a measurement object. FIG. 7 is a schematic cross-sectional view of a color sensor according to Embodiment 3 of the present invention. FIG. 8 is a schematic cross-sectional view showing a modification of the color sensor of the third embodiment. FIG. 9 is a schematic cross-sectional view of a color sensor according to Embodiment 4 of the present invention. FIG. 10 is a schematic cross-sectional view showing another example of the fourth embodiment. FIG. 11 is a schematic cross-sectional view of a color sensor according to Embodiment 5 of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments, and various design changes can be made without departing from the gist of the present invention.

(First embodiment)
The first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic cross-sectional view of a color sensor 11 according to the first embodiment. The color sensor 11 shown in FIG. 1 includes an illumination optical system and a light receiving unit 14, and the illumination optical system includes a light source 13, a curved reflecting mirror 15, an optical path separating unit 16, and an irradiation reflecting mirror 17.

The light source 13 and the light receiving unit 14 are mounted on the lower surface of the circuit board 12. The circuit board 12 is disposed so as to be parallel to the surface (measurement target surface) of the measurement target 20. In the following description, it is assumed that the surface of the measurement object 20 is in a horizontal plane.

The light source 13 is a white light source with a built-in LED chip, and is installed such that its optical axis A is perpendicular to the circuit board 12 (that is, the principal ray emitted from the light source 13 is directed vertically downward). ing.

A curved reflecting mirror 15 is disposed vertically below the light source 13. The curved reflecting mirror 15 is a reflecting mirror whose surface (mirror surface) is constituted by a part of a rotating paraboloid P obtained by rotating a parabola around its symmetry axis C. In the curved reflector 15, the focal point E of the original paraboloid P is coincident with the light emitting point of the light source 13, the symmetry axis C is parallel to the lower surface of the circuit board 12, and the symmetry axis C is the light receiving unit 14. The position is determined so as to intersect the optical axis B of Further, in this embodiment, as shown in FIG. 2, the curved reflecting mirror 15 (off-axis parabolic mirror) is formed with a curved surface in a region located in a direction orthogonal to the symmetry axis C from the focal point E of the rotating paraboloid P. It is composed.

The curved reflector 15 may have any structure. In the illustrated example, the curved reflecting mirror 15 is a metal film formed on the surface of a parabolic mirror support plate 18a of a plastic molded product. The metal film is formed on a part of the surface of the parabolic mirror support plate 18a by plating or vacuum deposition. The parabolic mirror support plate 18a is preferably made of a resin filled with a black resin or a light-absorbing material so as not to reflect light on a surface other than the region where the curved reflector 15 is provided. Further, the curved reflecting mirror 15 may be one in which the surface of a metal plate is polished and mirror-finished into a paraboloid.

As shown in FIG. 3, in the vertical plane including the optical axis A of the light source 13 and the optical axis B of the light receiving unit 14, the X axis is determined in parallel with the optical axis A with the light emitting point of the light source 13 as the origin, and the circuit board 12. If the Y axis is defined in parallel with the lower surface of the paraboloid, the symmetry axis C of the paraboloid P coincides with the Y axis, and the focal point of the paraboloid P is located at the light emitting point of the light source 13. The cross-sectional shape (parabola) of
4f (Y + f) = X ² (Formula 1)
It is represented by Here, f is the distance between the focal point E and the apex of P (hereinafter referred to as the focal length).

Thus, the light La emitted from the light source 13 and incident on the curved reflecting mirror 15 and reflected by the curved reflecting mirror 15 is converted into parallel light Lb and parallel to the symmetry axis C (or Y axis direction). move on.

Specifically, if the curved reflecting mirror 15 is disposed at a position 6 mm from the light emitting point of the light source 13 in the X-axis direction, the cross-sectional shape of the rotating paraboloid P is given by
Y = (1/12) X ² -3
(That is, f = 3). Further, if the length of the curved reflecting mirror 15 in the direction parallel to the Y axis is expressed by coordinates in the Y axis direction and −9/4 (mm) ≦ Y ≦ 15/4 (mm) (Y axis) Direction length ΔY = 6 mm), and the beam width ΔX in the X-axis direction of the parallel light Lb converted by the curved reflector 15 is 6 mm (3 (mm) ≦ X if the range of the beam is expressed by coordinates in the X-axis direction) ≦ 9 (mm)). In addition, the numerical value described here is an example, and the color sensor 11 of the present invention is not limited to these numerical values.

The cross-sectional area of the parallel light flux depends not only on the area of the curved reflecting mirror 15 but also on the value of the focal length f of the paraboloid P. When the focal length of the rotating paraboloid P is changed, even when the area of the curved reflecting mirror 15 is the same, the cross-sectional area and light intensity of the parallel light Lb change.

An optical path separating means 16 is arranged on the opposite side of the curved reflecting mirror 15 with the optical axis B of the light receiving unit 14 in between. In other words, the optical path separating means 16 is disposed at the destination where the parallel light Lb reflected by the curved reflecting mirror 15 travels horizontally. The optical path separating means 16 is constituted by two

plane mirrors

16a and 16b, and is bent in a substantially square shape. The normal lines of the plane mirrors 16a and 16b are oriented in a direction parallel to the vertical plane including the optical axes A and B. The optical path separating means 16 (plane mirrors 16a and 16b) is also formed by forming a metal film on the surface of the support plate 19 which is a plastic molded product by a method such as plating or vapor deposition. Alternatively, the surface of the metal plate may be polished and mirror-finished.

Below the curved reflecting mirror 15, a flat-shaped irradiation reflecting mirror 17 is provided. The irradiation reflecting mirror 17 is a flat mirror in which a metal film is formed on the surface of the reflecting mirror support plate 18b made of a plastic molded product by a method such as plating or vacuum deposition. Alternatively, the surface of the metal plate may be polished and mirror-finished. The irradiation reflecting mirror 17 is tilted so that the normal direction thereof is parallel to the vertical plane including the optical axes A and B.

In the illustrated example, the paraboloid mirror support plate 18a and the reflector support plate 18b are integrally formed to be an integral support plate 18, but they may be separated. However, if the parabolic mirror support plate 18a and the reflector support plate 18b are integrated, the number of components is reduced, and the position adjustment during component assembly is facilitated. Is preferred.

The light receiving unit 14 is arranged immediately above the measurement target surface so that the optical axis B is perpendicular to the measurement target surface. Although not described in detail, the light receiving unit 14 includes a condensing lens, a diffraction grating, a sensor array, and the like.

In FIG. 1, the measurement window 22 is located below the measurement window 22 of the housing 21 in which the colorimeter is housed. However, this depends on the use of the colorimeter. In some cases, the measurement object 22 may flow on the conveyor in the production line, and in that case, the measurement meter is arranged above the line away from the measurement window 22. Alternatively, the measurement object 20 may be positioned above and the color sensor 11 may irradiate light from below to the lower surface of the measurement object 20.

In the light source 13, as shown in FIG. 1, the light La emitted from the light source 13 is reflected by the curved reflecting mirror 15 to become parallel light Lb and enters the optical path separating means 16. . Half of the parallel light Lb incident on the optical path separating means 16 is reflected by the flat mirror 16a, and the parallel light Lc reflected by the flat mirror 16a is irradiated on the upper surface of the measuring object 20 from a certain direction. The remaining half of the parallel light Lb incident on the optical path separating means 16 is reflected by the plane mirror 16 b, and the parallel light Ld reflected by the plane mirror 16 b is incident on the irradiation reflecting mirror 17. The parallel light Ld incident on the irradiation reflecting mirror 17 is reflected by the irradiation reflecting mirror 17, and the parallel light Le reflected by the irradiation reflecting mirror 17 is irradiated on the upper surface of the measuring object 20 from different directions.

Further, in this color sensor 11, an angle θ2 (hereinafter referred to as an irradiation angle) formed by the parallel light Lc that irradiates the measurement target surface and a normal N standing on the measurement target surface, and a parallel light Le that also irradiates the measurement target surface. Is equal to the irradiation angle θ5. If the angle formed by the plane mirror 16a with the Y-axis direction (or the angle formed with the plane parallel to the measurement target surface) is θ1, the irradiation angle θ2 of the parallel light Lc is
θ2 = 2θ1-90 ° (Formula 2)
It is represented by Further, if the angle formed by the plane mirror 16b with the Y axis is θ3 and the angle formed by the irradiation reflecting mirror 17 with the Y axis is θ4, the irradiation angle θ5 of the parallel light Le is
θ5 = 2 (θ3 + θ4) −270 ° (Equation 3)
It is represented by Therefore, in order to make the irradiation angles θ2 and θ5 of the parallel lights Lc and Le that irradiate the measurement target surface equal,
θ1 = θ3 + θ4-90 ° (Formula 4)
Should be satisfied.

For example, in order to set the irradiation angle of the parallel light Lc to θ2 = 20 °, from Equation 2, θ1 = 55 ° may be set. Further, in order to set the irradiation angle θ5 of the parallel light Le to 20 °, which is the same as θ2, it is sufficient that θ3 + θ4 = 145 ° from Equation 3, so that θ3 = 60 °, θ4 = 85 °, and the like.

In this way, if the irradiation angles θ2 and θ5 of the parallel lights Lc and Le are made equal, the same light is emitted even when the color sensor 11 is set 180 degrees around the normal line N of the measurement target surface. The surface to be measured is irradiated, and the reproducibility and reliability of the measurement results are improved.

Further, according to the color sensor 11, light can be applied to the measurement target surface from two directions with a single light source, and the number of light sources can be halved compared to the number of directions in which parallel light is irradiated. The cost of the color sensor can be reduced. In addition, when used in a portable or portable colorimeter, battery consumption can be reduced.

Further, in this color sensor 11, since the light irradiated onto the measurement target surface is made parallel light, the parallel light is less likely to hit members around the measurement target surface (for example, the casing 21 around the measurement window 22). . As a result, it is possible to prevent the light reflected by the surrounding members from entering the light receiving section and causing noise, improving the sensitivity of the colorimeter, and measuring the measurement target surface with low reflectance. It becomes easy.

In addition, since the color sensor 11 uses the curved reflecting mirror 15 (off-axis parabolic mirror) that does not include the region near the apex of the rotating paraboloid P, the light reflected by the curved reflecting mirror 15 is reflected by the light source 13. There is no shadow, and the reliability of the color sensor 11 is improved.

In the above embodiment, a dihedral mirror is used as the optical path separating means 16, but if three or more plane mirrors are used, the optical path of parallel light can be separated into three or more, and the measurement target plane has three directions. It is also possible to irradiate parallel light from the above directions.

(Second Embodiment)
FIG. 5 is a plan view of the color sensor 31 according to the second embodiment of the present invention. The color sensor 31 includes a plurality of sets of the illumination optical systems described in the first embodiment so as to be substantially rotationally symmetric about the optical axis B of the light receiving unit 14. In particular, in the illustrated example, two sets of illumination optical systems are provided around the optical axis B so as to form an angle of 90 °, and the FF section and the GG section in FIG. 5 are the same as those in FIG. It has a structure.

If such a color sensor 31 is used, as shown in FIG. 6, it is possible to irradiate parallel lights Lc and Le from a plurality of directions (four directions in FIG. 6) with the same irradiation angle, and to measure various surface materials. The surface can be measured with good reproducibility.

(Third embodiment)
FIG. 7 is a schematic sectional view showing a color sensor 41 according to Embodiment 3 of the present invention. In this color sensor 41, the light source 13 and the curved reflecting mirror 15 (that is, the symmetry axis C of the rotating paraboloid P) are rotated around an axis perpendicular to the paper surface, and the light is emitted from the light source 13 and paralleled by the curved reflecting mirror 15. The light source 13 and the curved reflecting mirror 15 are tilted so that the measurement target surface exists on the extension of the collimated light Lb. The optical path separation means 16 is formed by a flat mirror 16c and is arranged so as to block half of the parallel light Lb emitted from the curved reflecting mirror 15. Accordingly, the other half of the parallel light Lb emitted from the curved reflecting mirror 15 is irradiated onto the surface of the measurement object 20 at a certain irradiation angle.

The irradiation reflecting mirror 17 is disposed on the opposite side of the curved reflecting mirror 15 and the optical path separating means 16 with the optical axis B interposed therebetween. Of the parallel light Lb emitted from the curved reflecting mirror 15, half of the parallel light Ld reflected by the flat plate mirror 16 c (optical path separating means 16) is incident on the irradiation reflecting mirror 17 and reflected by the irradiation reflecting mirror 17. Thus, the parallel light Le is irradiated on the surface of the measurement target 20. Although the parallel light Le is irradiated to the measuring object 20 from the opposite side to the parallel light Lc, it is preferable that the irradiation angle of the parallel light Lc and the irradiation angle of the parallel light Le are also equal in this embodiment.

The parabolic mirror support plate 18a that supports the curved reflecting mirror 15 and the support plate 19 that supports the optical path separating means 16 may be separated, but if they are integrated as shown in FIG. Costs can be reduced, and position adjustment during assembly is facilitated.

In the embodiment of FIG. 7, the parallel light Lb is separated or divided into two optical paths using a flat mirror 16 c as the optical path separating unit 16. However, as shown in FIG. A mirror 16d may be used. In the modification shown in FIG. 8, the half mirror 16d is arranged on the optical path of the parallel light Lb emitted from the curved reflecting mirror 15, and half the parallel light Lc out of the parallel light Lb incident on the half mirror 16d is half mirror. The measurement object 20 is irradiated through 16d. The other half of the parallel light Lb incident on the half mirror 16d is incident on the irradiation reflecting mirror 17, and the parallel light Le reflected by the irradiation reflecting mirror 17 is irradiated on the measurement object 20. The

(Fourth embodiment)
Moreover, you may make it increase the parallel light irradiated to a measuring object surface by combining several sets of illumination optical systems with respect to one light-receiving part. For example, in the color sensor 51 shown in FIG. 9, the illumination optical system as shown in FIG. 1 is combined in a plurality of upper and lower stages (two stages in the illustrated example). Further, in the color sensor 52 shown in FIG. 10, the illumination optical system as shown in FIG. 7 is arranged symmetrically.

(Fifth embodiment)
If parallel light is used as light to irradiate the measurement object, the colorimeter becomes resistant to fluctuations in the detection distance. However, the light applied to the detection target is not limited to the parallel light, and may be converged light that is gently focused. FIG. 11 is a schematic sectional view showing an example of this.

In the surface light source device 61 shown in FIG. 11, for example, a spherical reflecting mirror (concave race) is used as the curved reflecting mirror 62, and the light emitting point of the light source 13 is arranged at a position slightly away from the spherical reflecting mirror from the focal position of the spherical reflecting mirror. is doing. The light La emitted from the light source 13 is reflected by the curved reflecting mirror 62 to be gradually converged light Lg and travels toward the optical path separating means 16. Part of the focused light Lg reflected by the flat mirror 16a is irradiated onto the measurement object 20 from the direction that is the focused light Lh. Further, a part of the focused light Lg reflected by the plane mirror 16b becomes the focused light Li, is further reflected by the irradiation reflecting mirror 17, and becomes the focused light Lj and is irradiated onto the measurement object 20 from another direction. . The focused lights Lh and Lj are not condensed before being incident on the measurement object 20, and are irradiated onto the measurement object surface with an appropriate beam cross section.

11, 31, 41, 42, 51, 52, 61 ... color sensor 13 ... light source 14 ...

light receiving unit

15, 62 ... curved reflector 16 ... optical path separating means 16a ... plane mirror 16b ... plane mirror 16c ... flat mirror 16d ... Half mirror 17 ... Reflecting mirror 20 ... Object to be measured A ... Optical axis of light source B ... Optical axis of light receiving part P ... Rotating paraboloid C ... Axis of symmetry of rotating paraboloid E ... Focal point of rotating paraboloid

Claims

One or more light sources;
A curved reflector that converts light emitted from the light source into non-diffused light;
An optical path separating means for separating the optical path of the non-diffused light into different optical paths;
An irradiating reflecting mirror that reflects the light of some of the plurality of optical paths separated by the optical path separating means;
Irradiate the surface to be measured with non-diffused light reflected by the irradiating reflector, and irradiate non-diffused light in light paths other than the part of the plurality of optical paths separated by the optical path separating means. A color sensor characterized in that the surface to be measured is irradiated from a different direction from the non-diffused light reflected by the reflector.
The curved reflecting mirror is a parabolic mirror whose mirror surface forms a part of a rotating paraboloid, and is arranged so that a focal point of the rotating paraboloid coincides with a light emitting point of the light source. The color sensor according to claim 1.
The color sensor according to claim 2, wherein the curved reflecting mirror does not include a region near the apex of the rotating paraboloid.
The optical path separation means separates the optical path of the non-diffused light into a plurality of different optical paths by reflecting the non-diffused light converted by the curved reflecting mirror in a plurality of directions. The described color sensor.
2. The optical path separating unit separates the optical path of the non-diffused light into a plurality of different optical paths by blocking and reflecting a part of the non-diffused light converted by the curved reflecting mirror. The color sensor described in 1.
The optical path separating means transmits a part of the non-diffused light converted by the curved reflector and reflects the remaining non-diffused light, thereby changing the optical path of the non-diffused light to a plurality of different optical paths. The color sensor according to claim 1, wherein the color sensor is separated.
The color sensor according to claim 1, wherein non-diffused light is irradiated to the measurement target surface from different directions at an equal angle with respect to a direction perpendicular to the measurement target surface.
The color sensor according to claim 1, wherein the curved reflecting mirror and the irradiating reflecting mirror are integrally formed.
2. The color sensor according to claim 1, further comprising a plurality of light sources and a pair of curved reflectors, optical path separating means, and irradiation reflectors corresponding to each of the plurality of light sources.
A plurality of sets of illumination optical systems including a light source, a curved reflecting mirror, a light separating means, and an irradiation reflecting mirror are provided, and the illumination optical system is arranged around a central axis perpendicular to the measurement target surface. The color sensor according to claim 9.
The color sensor according to claim 1, wherein light emitted from the light source is reflected by the curved reflecting mirror to be converted into gently focused light.