JPH10213482A - Color measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To take in simultaneously a plurality of light fluxes from an object to be measured for calculation of color value with a single plate type measuring apparatus easy to cool a photographing means. SOLUTION: A light flux 1 incident from an object to be measured on a plane mirror group consisting of a half mirror 6, a dichroic mirror 7 and a total reflection mirror 8 is divided into a light flux 1a reflected by the half mirror 6, a light flux reflected by the dichroic mirror 7 and a light flux 1b reflected by the total reflection mirror 8. The light fluxes 1a, 1b, 1c are transmitted respectively through the corresponding filters 9a, 9b and 9c and focused by a second relay lens 11 to image third images in different positions on the photographing surface of a CCD area sensor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color measuring device for two-dimensionally measuring a color value of an object to be measured.

[0002]

2. Description of the Related Art Conventionally, a rotary filter plate having a plurality of band-pass filters having different pass bands is provided with a device to be measured and a CCD.
And a color classification device (Japanese Patent Laid-Open No. 7-120324) in which the rotary filter plate is rotated to sequentially capture images passing through the filters, and a color CCD camera R, G, A color measuring device which converts a B signal into tristimulus values X, Y, Z by calculation (Japanese Patent Laid-Open No. 8-114)
No. 503) has been proposed.

[0003]

However, in the color classification apparatus described in Japanese Patent Application Laid-Open No. Hei 7-120324, the color value is obtained by making the filter have characteristics approximating the CIE color matching functions X, Y and Z. Although it can be obtained, since the filter is rotated and the image data is sequentially taken in, the data of the tristimulus values X, Y, and Z are shifted when the measured object moves at a high speed. It is necessary to remove the influence of this displacement, but it is difficult in principle to completely remove the influence of this displacement.

On the other hand, in the color measuring apparatus described in Japanese Patent Application Laid-Open No. H08-114503, the R, G, and B signals can be simultaneously captured, so that there is no effect due to the movement of the object to be measured.
The numerical conversion from the B signal to the tristimulus values X, Y, and Z is only an approximation, and an error increases depending on the color.

In the color measuring apparatus described in the publication, a color CCD camera is used. The color CCD camera includes a single-plate type and a three-plate type.
Since the G and B pixels are different, there is a disadvantage that if there is unevenness among the three pixels, an error occurs in the color value.

[0006] Furthermore, the S / N is reduced by cooling the CCD.
Although the ratio can be improved, in the case of the three-plate type, there is a problem that it is difficult to cool the CCD since three monochrome CCDs are attached to the color separation prism.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problem, and separates the luminous flux from the same part of the object to be measured, thereby facilitating the cooling of the imaging means. It is an object of the present invention to provide a color measurement device capable of simultaneously taking in luminous fluxes from light sources.

[0008]

According to the present invention, there is provided a separation optical system for separating a light beam emitted from a measurement surface of an object to be measured into a predetermined number, and a single optical system for two-dimensionally imaging the light beam incident on an imaging surface. An imaging unit, an imaging optical system that forms each light beam separated into the predetermined number at a different position on an imaging surface of the imaging unit, and between the separation optical system and the imaging unit,
The apparatus further comprises the predetermined number of filters arranged on the optical path of each of the separated light beams and having different spectral transmittances.

According to this structure, the light beams emitted from the measurement surface of the object to be measured are separated into a predetermined number, and the separated light beams pass through a predetermined number of filters having different spectral transmittances. Are formed at different positions on the imaging surface of a single imaging unit, and are imaged by this imaging unit. Thus, since there is a single imaging unit, it can be easily cooled, and light beams from the same part of the object to be measured are simultaneously imaged.

Further, in the color measuring apparatus according to the first aspect, each of the filters is disposed between the separation optical system and the image pickup optical system, and the separation optical system emits light from a measurement surface of an object to be measured. A first optical system for converging a light beam to be focused and forming an image as a first image, a light beam from the first image being separated into a predetermined number, and separating the separated light beams into a second image on each of the filters. A second optical system that forms an image as a light beam. The imaging optical system forms a light beam transmitted through each of the filters on an imaging surface of the imaging unit.

According to this configuration, the light beams emitted from the measurement surface of the object to be measured are focused and formed as a first image, the light beams from the first image are separated into a predetermined number, and the separated light beams are separated. Is formed as a second image on each filter,
Each of the separated light beams will surely pass through the corresponding filter without being mixed with other light beams, and the light beams transmitted through each filter will be imaged on the imaging surface of the imaging means, respectively. An imaging result can be obtained with high accuracy.

Further, in the color measuring apparatus according to claim 2, the second optical system includes a convex lens optical system having a focal point located near an image forming position of the first image, and the second optical system is measured by the convex lens optical system. A predetermined number of plane mirrors that are arranged at a position away from an object substantially perpendicular to the optical axis of the convex lens optical system, are arranged in directions different by a small angle from each other, and have different spectral transmittances, respectively. (Claim 3).

According to this structure, the light beam from the object to be measured is converted into a parallel light beam by the convex lens optical system whose focal point is located near the image forming position of the first image, and is incident on a predetermined number of plane mirrors.
Light beams having the spectral intensity corresponding to the spectral transmittance of each plane mirror are reflected in different directions by a small angle, so that the light beams from the same part of the measured object are separated into a predetermined number of light beams having different spectral characteristics. Becomes

Further, in the color measuring apparatus according to claim 3, the predetermined number of plane mirrors is a single total reflection mirror disposed farthest from the convex lens optical system, and the convex lens optical system is located closer to the total reflection mirror. And a half mirror disposed in close proximity to the first lens (claim 4).

According to this configuration, the light beam from the object to be measured, which has been converted into a parallel light beam by the convex lens optical system, enters the half mirror and is separated into transmitted light and reflected light at a ratio corresponding to the spectral transmittance of the half mirror. The reflected light is reflected at an angle corresponding to the direction of the half mirror, while the transmitted light is reflected by the total reflection mirror in a direction different from the reflected light of the half mirror by a small angle, so that the reflected light is reflected from the same part of the DUT. The luminous flux of
The reflected light from the half mirror and the reflected light from the total reflection mirror are separated.

Further, in the color measuring apparatus according to the present invention, the predetermined number of plane mirrors further includes a dichroic mirror disposed between the total reflection mirror and the half mirror (claim 5).

According to this configuration, the light beam from the object to be measured, which has been converted into a parallel light beam by the convex lens optical system, enters the half mirror and is separated into transmitted light and reflected light at a ratio corresponding to the spectral transmittance of the half mirror. The reflected light is reflected at an angle corresponding to the direction of the half mirror. On the other hand, the transmitted light is incident on the dichroic mirror, and the light flux in the wavelength range according to the spectral transmittance of the dichroic mirror is transmitted, and the light flux outside this wavelength range is reflected in a direction different from the reflected light of the half mirror by a small angle. I do. Further, the transmitted light of the dichroic mirror is reflected by the total reflection mirror in a direction different from that of the dichroic mirror by a small angle. As a result, the light beam from the same part of the device under test is separated into the reflected light from the half mirror, the reflected light from the dichroic mirror, and the reflected light from the total reflection mirror.

Further, in the color measuring apparatus according to claim 2, the second optical system includes the predetermined number of concave mirrors having different spectral transmittances, and these concave mirrors are:
The respective centers of curvature are arranged at positions close to the image forming position of the first image, and are arranged in directions different from each other by a small angle (claim 6).

According to this structure, the light beam from the object to be measured is incident on a predetermined number of concave mirrors, and the light beams having a spectral intensity corresponding to the spectral transmittance of each concave mirror are reflected in different directions by a small angle, so that the light beam is reflected. Light beams from the same part of the object to be measured are separated into a predetermined number of light beams having different spectral characteristics.

Further, in the color measuring apparatus according to the present invention, the predetermined number of concave mirrors may be a single total reflection mirror disposed farthest from the first optical system and the second total reflection mirror may be a second total reflection mirror. A half mirror disposed in close proximity to the first optical system (claim 7).

According to this configuration, the light beam from the object to be measured enters the half mirror, is separated into transmitted light and reflected light at a ratio corresponding to the spectral transmittance of the half mirror, and the reflected light is directed toward the half mirror. The transmitted light is reflected by the total reflection mirror in a direction different from the reflected light of the half mirror by a small angle, so that the light flux from the same part of the DUT is reflected by the half mirror. And the light reflected by the total reflection mirror.

Further, in the color measuring apparatus according to claim 7, the predetermined number of concave mirrors further include a dichroic mirror disposed between the total reflection mirror and the half mirror (claim 8).

According to this configuration, the light beam from the object to be measured enters the half mirror, is separated into transmitted light and reflected light at a ratio corresponding to the spectral transmittance of the half mirror, and the reflected light is directed toward the half mirror. Reflect at an angle according to. On the other hand, the transmitted light is incident on the dichroic mirror, and the light flux in the wavelength range according to the spectral transmittance of the dichroic mirror is transmitted, and the light flux outside this wavelength range is reflected in a direction different from the reflected light of the half mirror by a small angle. I do. Further, the transmitted light of the dichroic mirror is reflected by the total reflection mirror in a direction different from that of the dichroic mirror by a small angle. As a result, the light beam from the same part of the device under test is separated into the reflected light from the half mirror, the reflected light from the dichroic mirror, and the reflected light from the total reflection mirror.

According to a second aspect of the present invention, in the color measuring device, the second optical system includes a convex lens optical system having a focal point located near an image forming position of the first image, and a measurement target is formed by the convex lens optical system. A segment mirror disposed perpendicular to the optical axis of the convex lens optical system at a position away from the object,
This segment mirror has a reflecting surface in which a large number of minute regions in the predetermined number of directions different from each other by minute angles are formed.

According to this configuration, the light beam from the object to be measured is converted into a parallel light beam by the convex lens optical system whose focal point is located in the vicinity of the image forming position of the first image and is incident on the segment mirror. By reflecting light in different directions by minute angles according to the direction of the region, the light flux from the same part of the measured object is separated into a predetermined number of light fluxes.

Further, in the color measuring apparatus according to claim 2, the second optical system includes a convex lens optical system having an object point near an image forming position of the first image and an object to be measured by the convex lens optical system. A prism plate disposed perpendicular to the optical axis of the convex lens optical system at a position distant from the prism lens. It has a surface (claim 10).

According to this configuration, the light beam from the object to be measured is again incident on the prism plate by the convex lens optical system having the object point in the vicinity of the image forming position of the first image, and is incident on the prism plate. By emitting light in directions different by minute angles according to the direction of each minute region on the emission surface, light beams from the same portion of the object to be measured are separated into a predetermined number of light beams to form an image.

The color measuring apparatus according to any one of claims 1 to 10, wherein the predetermined number is three, and the three filters have a spectral transmittance of the three filters on the imaging surface of the imaging means. Are set so that the spectral characteristics of the output values corresponding to the third image of each of the CIEs are close to the spectral sensitivities X, Y, and Z of the standard observer of the CIE.

According to this configuration, the spectral transmittance of the three filters is such that the spectral characteristics of the output values corresponding to the three third images on the imaging surface of the imaging means are respectively the spectral sensitivity of the standard observer of the CIE. Since the values are set so as to approximate X, Y, and Z, the color value of the measured object can be accurately obtained.

[0030] In the color measuring apparatus according to the eleventh aspect, the spectral transmittances of the three filters include a spectral intensity of illumination light for illuminating a known object to be measured, a spectral transmittance of the separation optical system, and It is set in advance in consideration of the spectral sensitivity of the imaging means (claim 12).

According to this configuration, the spectral intensity of the illuminating light for illuminating the object to be measured, the spectral transmittance of the separation optical system, and the spectral sensitivity of the imaging unit are known, and the spectral transmittance of the three filters is Using these values, the spectral characteristics of the output values corresponding to the three third images on the imaging surface of the imaging unit become values close to the spectral sensitivities X, Y, and Z of the standard observer of CIE, respectively. As a result, the spectral transmittance of each filter is set with high accuracy, and
The color value of the measured object can be accurately obtained.

[0032]

FIG. 1 is a block diagram showing an optical system of an embodiment of a color measuring apparatus according to the present invention. FIG. 2 is a view showing an arrangement of a group of plane mirrors M1 as viewed from an arrow A in FIG. FIG. 4 is a characteristic diagram showing the spectral transmittance and spectral reflectance of the half mirror 6, the dichroic mirror 7, and the total reflection mirror 8 constituting the plane mirror group M1.

This color measuring device, as shown in FIG.
An illumination unit L for illuminating an unillustrated DUT is provided, and a light flux 1 from the DUT illuminated by the illumination unit L
Passes through the imaging lens 2, the aperture 3a of the aperture plate 3, the field lens 4, and the first relay lens 5, is reflected by the plane mirror group M1 (FIG. 2), and is again reflected by the first relay lens 5, the field lens 4. Opening 3b of aperture plate 3
, Then through filters 9a, 9b, 9c,
The second relay lens 11 is reflected by the reflection mirror 10
, And is incident on the CCD area sensor 12.

The illuminating means L has a light source such as a xenon lamp or a fluorescent lamp, and is configured using a known integrating sphere or other optical system. The imaging lens 2 is composed of a convex lens, and focuses the light beam 1 and forms an image on the opening 3 a of the aperture plate 3.

The field lens 4 is composed of a convex lens, is arranged so that its optical axis φ is parallel to the optical axis of the imaging lens 2, and its upper half faces the opening 3 a of the aperture plate 3. The lower half is arranged so as to face the opening 3 b of the aperture plate 3. The openings 3a and 3b of the aperture plate 3 are provided at positions symmetrical to each other with respect to the optical axis φ.

The first relay lens 5 is composed of a lens group functioning as a convex lens, and is arranged so that its optical axis coincides with the optical axis φ. It is arranged at a conjugate position, and its focal point coincides with the aperture plate 3.

As a result, the light beam 1 having passed through the first relay lens 5 becomes a parallel light beam and is incident on the plane mirror group M1, and the light beam reflected by the plane mirror group M1 is converged to form an aperture plate. The second image is formed on the third opening 3b.

The plane mirror group M1 comprises a flat half mirror 6, a dichroic mirror 7, and a total reflection mirror 8, respectively. The half mirror 6 has a spectral reflectance R ₆ (λ) and a spectral transmittance T ₆ (λ) shown in FIG. 3 and reflects part of incident light and transmits the rest. The dichroic mirror 7 has a spectral reflectance R ₇ (λ) shown in FIG.
And has a spectral transmittance T ₇ (λ), and reflects incident light in a part of the wavelength range and transmits the rest. The total reflection mirror 8 has a spectral reflectance R ₈ (λ) shown in FIG. 3 and reflects almost 100% of incident light.

As shown in FIGS. 1 and 2, the total reflection mirror 8 has a reflection surface arranged perpendicular to the optical axis φ.
When the incident light beam 1 passes through the half mirror 6 and the dichroic mirror 7, the light beam 1 is reflected by the total reflection mirror 8 to become a light beam 1b.

The half mirror 6 is arranged along an axis 6X-6Y perpendicular to the optical axis φ, as shown in FIG. 1, and has an axis with respect to a vertical plane of the optical axis φ, as shown in FIG. 6X
It is arranged in a direction rotated by _a small angle θa counterclockwise around −6Y, and when the incident light beam 1 is reflected by the half mirror 6, it becomes a light beam 1a.

As shown in FIG. 1, the dichroic mirror 7 is arranged along an axis 7X-7Y perpendicular to the optical axis φ, and as shown in FIG. around the 7X-7Y are arranged in a direction rotated clockwise by a small angle theta _c, the light beam 1 which is incident through the half mirror 6, a light beam 1c when reflected by the dichroic mirror 7.

That is, as shown in FIG. 2, the light beam 1 incident on the plane mirror group M1 is a light beam 1a reflected by the half mirror 6, a light beam 1c reflected by the dichroic mirror 7, and a total reflection mirror 8 The light is separated into the reflected light flux 1b.

The filters 9a, 9b, 9c are respectively provided with spectral transmittances T _a (λ), T _b (λ),
_Tc (λ), as shown in FIG. 1, the opening 3b of the aperture plate 3 is disposed so as to cover the opening 3b immediately to the left, and as shown in FIG. It is juxtaposed so as to divide into three.

The reflection mirror 10 includes filters 9a, 9b,
Immediately to the left of 9c, it is disposed at an angle of 45 ° with respect to the optical axis φ to change the direction of the incident light beam downward.
The second relay lens 11 includes a lens group functioning as a convex lens, and is arranged on an optical axis orthogonal to the optical axis φ.
This is for converging the incident light beam and forming an image on the imaging surface of the CCD area sensor 12 as a third image.

The CCD area sensor 12 includes a large number of CCDs.
Are two-dimensionally arranged, receive a light beam incident on the imaging surface, and output an electric signal of a level corresponding to the received light intensity.

The CCD area sensor 12 is mounted on a cooling device 13 as shown in FIG. The cooling device 13 cools the CCD area sensor 12 using the Peltier effect or the like, and the S / N ratio of each CCD is improved by cooling.

The CPU 31 comprises a microcomputer or the like having a ROM (not shown) for storing a control program and preset data and a RAM (not shown) for temporarily storing data. In addition to controlling the operation of the present measuring apparatus, the color value is calculated using the received light intensity data of the third image output from the CCD area sensor 12.

Next, the operation of this embodiment will be described with reference to FIGS. 1, 4 and 5. FIG. 4 is a front view of the aperture plate 3 showing a first image and a second image, and FIG. 5 is a view C showing a third image.
FIG. 3 is a plan view of the CD area sensor 12.

A light beam 1 from an object to be measured (not shown) is converged by an imaging lens 2 and forms a first image 21 at a position of an opening 3a of an aperture plate 3, as shown in FIG. The light beam forming the first image 21 passes through the opening 3 a of the aperture plate 3 as it is, and when transmitted through the field lens 4, is slightly deflected downward in FIG. 1 and enters the first relay lens 5. .

The light beam transmitted through the first relay lens 5 becomes a parallel light beam, enters the plane mirror group M1, is reflected by the half mirror 6, the dichroic mirror 7, and the total reflection mirror 8, and is separated into light beams 1a, 1b, and 1c. Then, the light enters the first relay lens 5 again.

Then, the separated light beams 1a, 1b, 1c
Are focused by the first relay lens 5, respectively.
As shown in FIG. 4, images are formed as second images 22a, 22b, and 22c at the positions of the openings 3b of the aperture plate 3.

The light beam forming the second image 22a passes through the filter 9a, is reflected by the reflection mirror 10, turns downward, and is converged by the second relay lens 11, as shown in FIG. Imaging area 12 of CCD area sensor 12
The image is formed as a third image 23a on a. Second image 22b, 2
Similarly, the luminous flux forming 2c also has a filter 9
b, 9c, is reflected by the reflection mirror 10, turned downward, is focused by the second relay lens 11, and is located on the imaging areas 12b, 12c of the CCD area sensor 12, as shown in FIG. Images are formed as third images 23b and 23c.

Next, the setting of the spectral transmittances T _a (λ), T _b (λ), and T _c (λ) of the filters 9a, 9b, 9c will be described. The light beam 1a is reflected by the half mirror 6, passes through the filter 9a, and forms a third image 23a.

[0054]

[Number 1] _{T Y (λ) = R 6} (λ) · T a (λ) ≒ Y (λ) Therefore, the spectral transmittance T _a of the filter 9a (lambda) is the spectral reflectance of the half mirror 6 R ₆ (lambda) and the product T _Y spectral transmittance T _a (λ) (λ) becomes a value approximate to CIE standard observer spectral sensitivity Y (lambda) of the filter 9a, i.e. so as to satisfy the above Equation 1 By setting the third image 23a to CI
An image based on the spectral sensitivity Y (λ) of the standard observer E can be obtained.

The light beam 1b passes through the half mirror 6 and the dichroic mirror 7, is reflected by the total reflection mirror 8, and is again returned to the half mirror 6 and the dichroic mirror 7.
To form a third image 23b.

[0056]

T _x1 (λ) = T ₆ (λ) · T ₇ (λ) · R ₈ (λ) · T ₇ (λ) ·
T ₆ (λ) · T _b (λ) ≒ X ₁ (λ) Accordingly, by setting the spectral transmittance T _b (λ) of the filter 9b so as to satisfy Expression 2, the third image 23 is obtained.
b can be an image based on the spectral sensitivity X ₁ (λ) of the standard observer of CIE.

The light beam 1c passes through the half mirror 6, is reflected by the dichroic mirror 7, and passes through the half mirror 6 again to form a third image 23c.

[0058]

T _z (λ) = T ₆ (λ) · R ₇ (λ) · T ₆ (λ) · T _c (λ) ≒ Z (λ) Therefore, the spectral transmittance T _c (λ ) Is set so as to satisfy Expression 3 above, whereby the third image 23 is obtained.
c can be an image based on the spectral sensitivity Z (λ) of a standard observer of CIE.

Here, the spectral sensitivity X of the standard observer of CIE
(λ) takes a value close to 0 in the vicinity of λ = 500 nm and has two maximum values. Therefore, X ₁ (λ) in the range of λ ≧ 500 nm and λ <50
Using X ₂ (λ) in the range of 0 nm,

[0060]

## EQU4 ## X (λ) = X ₁ (λ) + X ₂ (λ), where X ₂ (λ) is substantially similar to Z (λ). Z (λ). Therefore, in the above equation (2), instead of X (λ), X (λ)
It is set to a value close to ₁ (λ).

The total combined spectral transmittance T _Y (λ) of the half mirror 6, the dichroic mirror 7, the total reflection mirror 8, and the filters 9a, 9b, 9c through which the light beams forming the third images 23a, 23b, 23c pass. FIG. 6 shows T _x1 (λ) and T _Z (λ).
Shown in In FIG. 6, the values are normalized so that the maximum value of each value is 100%.

As described above, the light beam 1 from the object to be measured is separated into the light beams 1a, 1b, and 1c by using the half mirror 6, the dichroic mirror 7, and the total reflection mirror 8, and the separated light beams 1a, 1b, and 1c are separated. To the filters 9a, 9b, 9c
And the image is simultaneously captured by the CCD area sensor 12, so that even when the object to be measured is moving at a high speed, the measurement can be performed using the luminous flux from the same part of the object to be measured. Color values can be measured accurately.

Since the spectral transmittances T _a (λ), T _b (λ), and T _c (λ) of the filters 9a, 9b, and 9c are set so as to satisfy the above equations (1) to (3), the CIE It is possible to obtain received light intensity data based on spectral sensitivities approximating the spectral sensitivities X ₁ (λ), Y (λ), and Z (λ) of the standard observer, and thereby accurately obtain color values.

Further, since the CCD area sensor 12 is constituted by a single plate, the CCD area sensor 1 has a simple structure.
2 can be cooled, so that the S / N ratio of the CCD area sensor 12 can be easily improved.

Further, since the dichroic mirror 7 is used as a mirror constituting the plane mirror group M1, the loss of light quantity can be reduced. In FIG. 2, for example, the reflectance of the half mirror 6 is 35%, the transmittance is 65%, the transmittance of the dichroic mirror 7 in the transmission region and the reflectance in the reflection region is 90%, and the reflectance of the total reflection mirror 8 is 90%. Assuming 95%, luminous flux 1a: 35% luminous flux 1b: 0.65 × 0.9 × 0.95 × 0.9 × 0.65 × 100 = 32.5% luminous flux 1c: 0.65 × 0.9 × 0.65 × 100 = 38%. Can be suppressed.

Here, the reason why X ₁ (λ) in the long wavelength region is applied to the light beam 1b whose transmission number is large and the light amount loss is high is CC
This is because the sensitivity of D, the reflectance of the total reflection mirror, and the energy of most light sources are high in the long wavelength region.

When the illumination light from the illuminating means L is reflected on the object as the light beam 1 from the object, the opaque object color of the object can be measured.
When the illumination light from the illuminating means L uses light transmitted through the object, the color of the translucent object can be measured.

The present invention is not limited to the above embodiment, but can adopt the following modifications (1) to (7).

(1) Instead of Equations 1 to 3 in which only the spectral characteristics of the plane mirror group M1 are considered, in addition to the spectral characteristics of the plane mirror group M1, the spectral intensity of the illumination light of the illumination means L and the CCD
Considering the spectral sensitivity of the area sensor 12, the filter 9
a, 9b and 9c are set. Further, an imaging lens 2, a field lens 4, a first relay lens 5,
The spectral transmittance of each filter is set in consideration of the spectral characteristics of the entire optical system including the reflection mirror 10 and the second relay lens 11. According to these embodiments, the color value of the measured object can be obtained more accurately.

(2) The half mirror 6, the dichroic mirror 7, and the total reflection mirror 8 can be manually rotated about the axes 6X-6Y, 7X-7Y, and 8X-8Y, respectively, as shown by the dashed line in FIG. And a rotation adjusting unit 32 for adjusting the rotation angle of each of the mirrors 6, 7, and 8.

According to this embodiment, the images of the same part of the object to be measured are imaged on the imaging areas 12a and 12a on the CCD area sensor 12.
It is possible to accurately form an image on the corresponding sensor pixels b and 12c without a pixel shift.
An accurate color value can be obtained more reliably.

(3) Instead of the plane mirror group M1 including the half mirror 6, the dichroic mirror 7, and the total reflection mirror 8, a segment mirror 14 arranged perpendicular to the optical axis φ as shown in FIG. Prepare. Segment mirror 14
Is a band-like region 14b perpendicular to the optical axis φ and a band-like region 14
a and a strip-shaped reflective surface in which a large number of strip-shaped areas 14c downwardly by a small angle with respect to the area 14b are sequentially formed.

According to this embodiment, as shown in FIG. 7, a light beam 1 from an object to be measured is converted into a light beam 1a,
1b and 1c, whereby the same operation and effect can be obtained with a simpler configuration than the above embodiment.

(4) Instead of the first relay lens 5, the half mirror 6, the dichroic mirror 7, and the total reflection mirror 8, as shown in FIG. 8, a concave half mirror 61, a concave dichroic mirror 71, and a concave total reflection mirror are provided. A concave mirror group M2 consisting of 81 is provided. This mirror 61,7
5 have the same spectral characteristics as the mirrors 6, 7, 8 shown in FIG. 5, and are arranged such that the center of curvature coincides with the intersection of the optical axis φ and the aperture plate 3.

As shown in FIG. 9, the concave dichroic mirror 71 has a reflecting surface arranged perpendicular to the optical axis φ, and the light flux 1 incident along the optical axis φ and transmitted through the concave half mirror 61. Of the concave dichroic mirror 71
The component reflected at becomes a light beam 1a.

[0076] concave half mirror 61 is arranged in a direction rotated by a small angle [psi _b with respect to the vertical plane of the optical axis φ counterclockwise about an axis perpendicular to the plane of FIG. 9, the optical axis φ
Of the light beam 1 incident along the concave half mirror 61
The component reflected at becomes a light flux 1b.

The concave total reflection mirror 81 is arranged in a direction rotated clockwise around the axis perpendicular to the paper surface of FIG. 9 by a small angle 面_{c with} respect to the vertical plane of the optical axis φ. Are transmitted along the concave half mirror 61 and the concave dichroic mirror 71, and are reflected along the optical axis φ by the concave total reflection mirror 81 to become the light flux 1a.

That is, as shown in FIG. 9, the light beam 1 incident on the concave mirror group M2 has the light beam 1b reflected by the concave half mirror 61, the light beam 1a reflected by the concave dichroic mirror 71, and the concave total reflection. The light beam 1a reflected by the mirror 81 will be separated.

According to this embodiment, the light flux 1 from the object to be measured
Can be separated into luminous fluxes 1a, 1b, and 1c in the same manner as in the above-described embodiment, whereby the same operation and effect as those in the above-described embodiment can be obtained.

(5) Instead of the dichroic mirror 7,
A half mirror is used. In FIG. 2, for example, the reflectance of the half mirror 6 is 20%, the transmittance is 80%, the reflectance of the half mirror replacing the dichroic mirror 7 is 40%, the transmittance is 60%, and the reflectance of the total reflection mirror 8 is 95. %, Luminous flux 1a: 20% luminous flux 1b: 0.80 × 0.60 × 0.95 × 0.60 × 0.80 × 100 = 21.9
% Luminous flux 1c: 0.80 × 0.40 × 0.80 × 100 = 25.6% Therefore, according to this embodiment, the amount of light with respect to each light beam 1 is slightly reduced as compared with the case where the dichroic mirror 7 is used.

(6) Instead of a reflection optical system having a plane mirror group M1 including a half mirror 6, a dichroic mirror 7, and a total reflection mirror 8, as shown in FIG. And a transmission optical system provided with the prism plate 15 described above.

The prism plate 15 is, as shown in FIG.
The shape is substantially the same as that of the segment mirror 14 (FIG. 7) having a flat entrance surface and a stripe exit surface, and the exit surface has a band-like region 15b perpendicular to the optical axis φ, and this region 15b.
a band-like region 15a upward by a small angle with respect to b;
Band-like region 1 facing down by a small angle with respect to region 15b
5c are formed in order.

Further, since the transmission mirror is constituted by the transmission optical system using the prism plate 15, as shown in FIG. 10, the reflection mirror 10 becomes unnecessary, and the filter 9a and the filter 9a are disposed on the optical axis φ behind the prism plate 15. 9b, 9c, field lens 4,
A second relay lens 11, a CCD area sensor 12, and a cooling device 13 are sequentially arranged.

According to this embodiment, the light flux 1 from the object to be measured is
Can be separated into luminous fluxes 1a, 1b, and 1c in the same manner as in the above-described embodiment. As a result, similar to the above-described modification (3), the same operation and effect can be obtained while having a simpler configuration than the above-described embodiment. Obtainable.

(7) Instead of the half mirror 6 and the dichroic mirror 7, three half mirrors are provided, four filters are provided, and the light beam 1
The light beams are separated into a plurality of light beams and transmitted through each filter to form four third images.

The output of the CCD area sensor 12 based on the third image is the spectral transmittance of the filter, and the spectral sensitivity X ₁ (λ), X ₂ (λ), Y
(λ) and Z (λ) are set to approximate values.

According to this embodiment, X (λ) = X ₁ (λ) + X ₂
By setting (λ) = X ₁ (λ) + α · Z (λ), the received light intensity based on the spectral sensitivity close to the spectral sensitivity X (λ), Y (λ), Z (λ) of the standard observer of CIE. Data can be obtained so that color values can be accurately determined.

A filter approximating to X ₁ (λ),
Since a filter that approximates X ₂ (λ) is separately provided, design and manufacture of each filter can be easily performed.

[0089]

As described above, according to the present invention,
A light beam emitted from the measurement surface of the device under test is separated into a predetermined number of light beams, and the separated light beams are transmitted through a predetermined number of filters having different spectral transmittances. Are formed at different positions, and an image is picked up by this image pickup means, so that a single image pickup means can be easily cooled. Further, it is possible to simultaneously image light beams from the same part of the object to be measured, and thereby to accurately image regardless of the movement of the object to be measured.

Further, the light beam emitted from the measurement surface of the object to be measured is focused and formed as a first image, the light beam from the first image is separated into a predetermined number, and the separated light beam is applied to each filter. By forming an image as the second image, each separated light beam can surely pass through the corresponding filter without mixing with other light beams, and the light beams transmitted through each filter can be respectively transmitted to the imaging surface of the imaging unit. By forming an image, an imaging result of each light beam can be obtained with high accuracy.

Further, a light beam from the object to be measured is made into a parallel light beam and made incident on a predetermined number of plane mirrors by a convex lens optical system having a focal point located in the vicinity of the image forming position of the first image according to the spectral transmittance of each plane mirror. By reflecting the light beams having the different spectral intensities in different directions by minute angles, the light beams from the same portion of the object to be measured can be separated into a predetermined number of light beams having different spectral characteristics.

Further, the light beam from the object to be measured is made incident on the half mirror, and the light transmitted through the half mirror is reflected by the total reflection mirror, which is different from the half mirror by a small angle, so that the same portion of the object is measured. Can be separated into reflected light from a half mirror and reflected light from a total reflection mirror having different spectral characteristics.

A light beam from an object to be measured is made incident on a half mirror, light transmitted through the half mirror is made incident on a dichroic mirror having a direction slightly different from that of the half mirror, and light transmitted through the dichroic mirror is dichroic. The light from the same part of the device under test is reflected by a half mirror, dichroic mirror, Light can be separated into reflected light, and the use of a dichroic mirror can reduce a decrease in the amount of reflected light.

Also, the light beam from the object to be measured is made incident on a predetermined number of concave mirrors arranged at different angles by a small angle from each other, and is reflected at a spectral intensity corresponding to the spectral transmittance of each concave mirror, whereby the object to be measured is reflected. Can be separated into a predetermined number of light beams having different spectral characteristics.

Further, the light beam from the object to be measured, which has been converted into a parallel light beam, is incident on the segment mirror, and is reflected in different directions by a small angle according to the direction of each minute region of the segment mirror. The light beam from the site can be separated into a predetermined number of light beams.

Also, the convex lens optical system having an object point in the vicinity of the first imaging position causes the light beam to be incident on the prism plate immediately after the light is again focused, and is directed in the direction of each minute area on the exit surface of the prism plate. By irradiating the light beams in directions different from each other by a small angle, a light beam from the same part of the object to be measured can be separated into a predetermined number of light beams.

Further, the spectral transmittances of the three filters are represented by the spectral sensitivities X and C of the standard observer of the CIE, respectively.
By setting the values to approximate Y and Z,
The color value of the measured object can be accurately obtained.

Further, the spectral transmittances of the three filters are calculated as known spectral intensities of illumination light for illuminating an object to be measured.
By setting in advance in consideration of the spectral transmittance of the separation optical system and the spectral sensitivity of the imaging unit, the spectral transmittance of each filter can be set with high accuracy, and thereby the color value of the measured object can be accurately obtained. be able to.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an optical system of an embodiment of a color measurement device according to the present invention.

FIG. 2 is a view on arrow A of FIG. 1 showing an arrangement of a group of plane mirrors;

FIG. 3 is a characteristic diagram showing a spectral transmittance and a spectral reflectance of a half mirror, a dichroic mirror, and a total reflection mirror constituting a plane mirror group.

FIG. 4 is a front view of an aperture plate showing a first image and a second image.

FIG. 5 is a plan view of a CCD showing a third image.

FIG. 6 is a characteristic diagram showing the overall combined spectral transmittance of a half mirror, a dichroic mirror, a total reflection mirror, and each filter through which a light beam forming a third image passes.

FIG. 7 is a side view showing a shape of a segment mirror according to a modification (3).

FIG. 8 is a configuration diagram showing an optical system according to a modification (4).

FIG. 9 is a view on arrow A of FIG. 8 showing the arrangement of the concave mirror group;

FIG. 10 is a configuration diagram illustrating an optical system according to a modification (6).

FIG. 11 is a side view showing the shape of a prism plate according to a modification (6).

[Explanation of symbols]

REFERENCE SIGNS LIST 1 light beam from object 2 imaging lens (separation optical system, first optical system) 3 aperture plate 3 a, 3 b aperture 4 field lens 5 first relay lens (separation optical system, second optical system,
Convex lens optical system 6 Half mirror (separation optical system, second optical system, plane mirror) 7 Dichroic mirror (separation optical system, second optical system, plane mirror) 8 Total reflection mirror (separation optical system, second optical system) 9a, 9b, 9c Filter 10 Reflecting mirror (imaging optical system) 11 Second relay lens (imaging optical system) 12 CCD area sensor (imaging means) 13 Cooling device 14 Segment mirror (separating optical system, second) Optical system) 15 Prism plate (separating optical system, second optical system) 21a, 21b, 21c First image 22a, 22b, 22c Second image 23a, 23b, 23c Third image 31 CPU 32 Rotation driving unit 61 Concave half Mirror (separation optical system, second optical system,
Concave mirror) 71 concave dichroic mirror (separation optical system, second optical system, concave mirror) 81 concave total reflection mirror (separation optical system, second optical system,
Concave mirror) L Illumination means M1 Plane mirror group M2 Concave mirror group

Claims (12)

[Claims] 1. A separation optical system for separating a light beam emitted from a measurement surface of an object to be measured into a predetermined number, a single imaging means for two-dimensionally imaging a light beam incident on an imaging surface, and the predetermined number of light beams An imaging optical system that forms each of the separated luminous fluxes at different positions on the imaging surface of the imaging unit, between the separation optics and the imaging unit, and on the optical path of each of the separated luminous fluxes. A color measuring device, comprising: the predetermined number of filters arranged respectively and having different spectral transmittances. 2. A color measuring apparatus according to claim 1, wherein
The filters are respectively disposed between the separation optical system and the imaging optical system, and the separation optical system focuses a light beam emitted from the measurement surface of the device under test and forms a first image. A first optical system and a second optical system that separates a light beam from the first image into a predetermined number and forms each of the separated light beams as a second image on each of the filters. A color measuring apparatus, wherein the imaging optical system forms a light beam transmitted through each of the filters on an imaging surface of the imaging means. 3. The color measuring device according to claim 2, wherein
The second optical system has a convex lens optical system having a focal point near the image forming position of the first image, and a convex lens optical system at a position farther from the object than the convex lens optical system with respect to an optical axis of the convex lens optical system. A plurality of plane mirrors, which are arranged substantially perpendicularly to each other, are arranged in directions different from each other by a small angle, and have the predetermined number of plane mirrors having different spectral transmittances. 4. The color measuring device according to claim 3, wherein
The predetermined number of plane mirrors includes a single total reflection mirror disposed farthest from the convex lens optical system, and a half mirror disposed closer to the convex lens optical system than the total reflection mirror. Color measuring device. 5. The color measuring device according to claim 4, wherein
The color measuring apparatus according to claim 1, wherein the predetermined number of plane mirrors further includes a dichroic mirror disposed between the total reflection mirror and the half mirror. 6. The color measuring device according to claim 2, wherein
The second optical system includes the predetermined number of concave mirrors having different spectral transmittances, and the concave mirrors are each disposed at a position where the center of curvature is close to the imaging position of the first image, A color measuring device, wherein the color measuring devices are arranged in directions different from each other by minute angles. 7. The color measuring device according to claim 6, wherein
The predetermined number of concave mirrors includes a single total reflection mirror disposed farthest from the first optical system and a half mirror disposed closer to the first optical system than the total reflection mirror. A color measuring device comprising: 8. The color measuring device according to claim 7, wherein
The color measuring apparatus according to claim 1, wherein the predetermined number of concave mirrors further includes a dichroic mirror disposed between the total reflection mirror and the half mirror. 9. The color measuring apparatus according to claim 2, wherein
The second optical system has a convex lens optical system having a focal point near the image forming position of the first image, and a convex lens optical system at a position farther from the object than the convex lens optical system with respect to an optical axis of the convex lens optical system. And a segment mirror arranged vertically, the segment mirror having a reflection surface formed with a large number of minute regions in the predetermined number of directions different from each other by minute angles. 10. The color measuring apparatus according to claim 2, wherein the second optical system has a convex lens optical system having an object point near an image forming position of the first image, and an object to be measured by the convex lens optical system. A prism plate disposed perpendicular to the optical axis of the convex lens optical system at a position distant from the prism lens. A color measuring device having a surface. 11. The color measuring apparatus according to claim 1, wherein said predetermined number is three, and said three filters have a spectral transmittance of said three filters on an imaging surface of said imaging means. The spectral characteristics of the output values corresponding to the third image
A color measuring apparatus characterized in that the values are set so as to approximate the spectral sensitivities X, Y, and Z of the IE standard observer. 12. The color measuring apparatus according to claim 11, wherein the spectral transmittances of the three filters are respectively a spectral intensity of illumination light for illuminating a known object to be measured, a spectral transmittance of the separation optical system, and A color measuring device, which is set in advance in consideration of the spectral sensitivity of the imaging means.