Spectrophotometer

Abstract

The present invention comprises: a light-receiving optical system (3) that receives measurement target light from a sample (100) to be measured and forms an image; a slit member (5) that has a slit (51) disposed at an image-forming position of the light-receiving optical system; a spectroscopic means (7) that separates the measurement target light L that has passed through the slit (51); a sensor (8) that receives the separated light and outputs a spectroscopic signal of the measurement target light (L); an observation light source (9) that is disposed on the optical path of the zero-order light of the spectroscopic means (7), and emits observation light toward the spectroscopic means (7) to illuminate the slit (51); and a diffusion member (10) that is disposed between the observation light source (9) and the spectroscopic means (7), and diffuses the light emitted from the observation light source (9). The light-receiving optical system (3) forms an image of the slit (51) on a measurement surface of the sample (100).

Description

spectrophotometer

[0001] The present invention relates to a spectrophotometer capable of observing a measurement position on a sample surface during measurement of the sample.

[0002] As a spectrophotometer capable of observing the position to be measured as described above, the following spectrophotometer is disclosed in Japanese Patent Application Laid-Open No. 2003-222299.

[0003] This spectrophotometer is equipped with a light-receiving optical system that receives and images the light to be measured from the sample to be measured, and a slit-forming element with a slit that passes the imaged light to be measured and generates light to be measured that travels along a measurement optical path. The slit and the surface of the sample to be measured are in a conjugate relationship. The light to be measured that travels along the measurement optical path is diffracted by a diffraction grating. The diffracted light is received by a sensor, which outputs a signal representing the spectral spectrum. An observation light source is also positioned on the optical path of the zeroth-order light of the diffracted light.

[0004] In this spectrophotometer, when observing the measurement position on the sample surface, observation light is emitted from the observation light source toward the diffraction grating. A slit image illuminated by the observation light source is then formed on the measurement surface of the sample. Then, by photographing the measurement surface of the sample on which the slit image has been formed with an observation camera or the like, the slit image serves as a pointer indicating the position of the measurement surface, allowing the measurer to confirm the measurement position.

[0005] This situation is shown in Figure 6. Figure 6 shows an image of the measurement surface of the sample on which the slit image is formed, captured by an observation camera. In Figure 6, the circular area 401 in the center is the aperture of the colorimeter. The rectangular area 402 that is approximately inscribed in the circular area 401 of the aperture is the outline of the hole in the target mask, and is the measurement aperture. The area inside the outline is the surface of the sample. Furthermore, the rectangular area 403 on the surface of the sample is the image of the slit, and this area serves as the pointer.

[0006] International Publication No. 2018 / 221082

[0007] In the above-mentioned spectrophotometer, the image of the slit illuminated by the observation light source serves as a pointer indicating the measurement position. Therefore, uneven illumination on the slit is projected onto the measurement surface, causing uneven light intensity on the pointer, making observation difficult. This uneven light intensity becomes more pronounced and has a greater impact the smaller the observation light source. In other words, when the observation light source is small, only a portion of the slit is strongly illuminated, resulting in only a portion of the slit image on the measurement surface being bright, while the other portions are relatively dark, resulting in noticeable uneven light intensity. Furthermore, if there is an error in the position of the concave mirror or diffraction grating, especially in the rotational direction, the light from the observation light source will not be properly guided to the slit, resulting in noticeable uneven light intensity.

[0008] It is possible to reduce uneven light intensity by increasing the size of the observation light source, but because the observation light source is made up of LEDs and other elements, there is a limit to how large the observation light source can be made, and it would also be costly.

[0009] An object of the present invention is to provide a spectrophotometer that can suppress unevenness in the amount of light in the image of a slit formed on the measurement surface of a sample without increasing the size of the observation light source.

[0010] The above object is achieved by the following means: (1) A spectrophotometer comprising: a light-receiving optical system that receives and images light to be measured from a sample to be measured; a slit member having a slit positioned at an imaging position of the light-receiving optical system; spectroscopic means that disperses the light to be measured that has passed through the slit; a sensor that receives the light dispersed by the spectroscopic means and outputs a spectral signal of the light to be measured; an observation light source that is positioned in the optical path of the zeroth-order light of the spectroscopic means and emits observation light; and a diffusing member that is positioned between the observation light source and the spectroscopic means and diffuses the light emitted from the observation light source and generates diffused light directed toward the spectroscopic means, wherein the light-receiving optical system forms an image of a slit on the measurement surface of the sample, the slit being illuminated by the diffused light that is directed toward the spectroscopic means and reflected by the spectroscopic means. (2) The spectrophotometer according to the preceding paragraph 1, further comprising: an integrating sphere having a measurement opening; an illumination light source that illuminates the sample placed in the measurement opening with diffused light from the integrating sphere and generates the light to be measured; and an auxiliary light source that emits light together with the observation light source and illuminates the sample. (3) The spectrophotometer according to the preceding paragraph 1 or 2, further comprising a light-shielding wall between the observation light source and the sensor to prevent the observation light from the observation light source from entering the sensor. (4) The spectrophotometer according to the preceding paragraph 3, further comprising: a light-shielding unit having a cylindrical space, the light-shielding unit accommodating the diffusing member and the observation light source, and the diffused light being directed toward the spectroscopic means through the cylindrical space. (5) The spectrophotometer according to the preceding paragraph 3, further comprising: a stepped wall surface on the sensor side of the light-shielding wall. (6) The spectrophotometer according to the preceding paragraph 3, further comprising: a substrate on which the observation light source is mounted, and the substrate is subjected to a light-shielding treatment. (7) The spectrophotometer according to the preceding paragraph 1 or 2, further comprising: a light-shielding member disposed with its normal tilted relative to the optical axis of the zero-order light. (8) A spectrophotometer as described in the preceding paragraph 4, in which the slit member, the spectroscopic means, and the sensor are housed in a light-shielding case, the light-shielding unit is attached by being fitted into a mounting hole in the light-shielding case, and the light-shielding unit is formed with a first light-shielding protrusion for preventing stray light from outside the light-shielding case from entering the light-shielding case.(9) A spectrophotometer according to the preceding paragraph 4, wherein the slit member, the spectroscopic means, and the sensor are housed in a light-shielding case, the light-shielding unit is attached by being fitted into a mounting hole in the light-shielding case, the light-shielding case is formed with an incident prevention member that prevents the zero-order light from being incident on the sensor during color measurement, and the light-shielding unit is formed with a second light-shielding protrusion that prevents the zero-order light from the spectroscopic means from slipping through a gap between the incident prevention member and the light-shielding unit to the sensor side.

[0011] In the spectrophotometer according to the present invention, when observing a measurement position on a sample surface, observation light emitted from an observation light source arranged in the optical path of the zero-order light of the spectroscopic means is diffused by a diffusing member and directed as diffused light toward the spectroscopic means. The diffused light directed toward the spectroscopic means is reflected by the spectroscopic means and directed toward the slit, illuminating the slit. An image of the illuminated slit is formed on the measurement surface of the sample by the light-receiving optical system.

[0012] In this way, the observation light is diffused by the diffusing member to generate diffused light, and this diffused light is used to illuminate the slit, thereby achieving the same effect as using a larger observation light source without increasing its size. Therefore, compared to illuminating the slit without diffusion, the entire slit can be illuminated with a uniform amount of light. Therefore, the slit image formed on the measurement surface of the sample also has reduced unevenness in the amount of light. As a result, when the observer uses the slit image on the measurement surface as a pointer to observe the measurement position, the pointer's light intensity is uniform, allowing for better observation.

[0013] 1 is a diagram illustrating the configuration of a spectrophotometer according to an embodiment of the present invention. (A) is a perspective view showing a light-shielding unit, a substrate on which an observation light source is mounted, and a diffusing member, separated from each other, and (B) is a perspective view showing the state before the light-shielding unit is attached to the light-shielding case. It is a perspective view showing the state in which the substrate on which an observation light source is mounted and the light-shielding unit accommodating the diffusing member are attached to the light-shielding case. It is a cross-sectional perspective view of the state in FIG. 3, viewed obliquely from below. It is a cross-sectional view taken along line V-V in FIG. 3. It is a diagram schematically illustrating the state in which a slit image is formed on the surface of a sample during observation.

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0015] Fig. 1 is a diagram showing the configuration of a spectrophotometer 1 according to an embodiment of the present invention. Although Fig. 1 shows a vertical spectrophotometer 1 as an example, the spectrophotometer 1 may also be a horizontal or oblique type.

[0016] The spectrophotometer 1 has an integrating sphere 2, and a sample opening 21 is formed on the lower end side of the integrating sphere 2. This sample opening 21 is a portion where a sample 100 to be measured is placed via a target mask (not shown). A hole formed in the target mask serves as the measurement opening.

[0017] A light-receiving aperture 22 is formed near the top of the integrating sphere 2 on the side opposite to the aperture 21. This light-receiving aperture 22 is formed at an angle of 8 degrees with respect to the normal to the sample 100 placed in the sample aperture 21 via the target mask. In addition, a light-receiving optical system 3 is disposed on the straight line connecting the sample 100 and the light-receiving aperture 22.

[0018] The integrating sphere 2 further has a circular trap hole 23 formed at a position symmetrical to the light-receiving opening 22 with respect to the normal to the sample 100. The trap hole 23 can be opened and closed by a trap 24.

[0019] Illumination light source 4 is arranged around integrating sphere 2 to illuminate the inner surface of integrating sphere 2 during color measurement, and the light irradiated onto the inner surface of integrating sphere 2 from illumination light source 4 is multiply diffused by the inner surface of integrating sphere 2. This diffused light illuminates sample 100, which reflects the diffused light. Light-receiving optical system 3 receives the reflected light from sample 100 as light L to be measured.

[0020] The light-receiving optical system 3 has a light-receiving lens 31 that receives and images the light to be measured L from the sample 100. Behind the light-receiving optical system 3, a slit member 5 having a slit 51 is arranged so that the slit 51 is positioned at the position where the light to be measured L is imaged by the light-receiving lens 31. The slit 51 of the slit member 5 and the measurement surface of the sample 100 are in a conjugate relationship.

[0021] Furthermore, a concave mirror 6 that reflects the light that has passed through the slit 51 is disposed behind the slit member 5. A diffraction grating 7 serving as a spectroscopic means is disposed at a position where it can receive the light reflected by the concave mirror 6, and a light-receiving sensor 8 is disposed at a position where it can receive the light that has been dispersed into wavelengths by the diffraction grating 7. The light-receiving sensor 8 outputs a spectral signal of the light L to be measured.

[0022] In this embodiment, an observation light source 9 is disposed in the optical path of the 0th (zeroth) order light L0 from the diffraction grating 7, which receives the light reflected by the concave mirror 6. This observation light source 9 is a light source used by an operator measuring the sample 100 to check the measurement position prior to measuring the sample 100, and is configured with an LED or the like.

[0023] In addition, a diffusion plate 10, which is a diffusion member, is disposed on the optical path of the observation light source 9 between the observation light source 9 and the diffraction grating 7. This diffusion plate 10 serves to diffuse the light from the observation light source 9 to generate diffused light, and the light from the observation light source 9 is diffused by the diffusion plate 10 and travels as diffused light toward the diffraction grating 7. The diffused light reflected by the diffraction grating 7 then travels in the opposite direction along the optical path of the zero-order light L0 and illuminates the slit 51 in the slit member 5.

[0024] In this embodiment, the diffuser 10 is disposed with its normal line tilted with respect to the optical axis La of the zero-order light L0 from the diffraction grating 7. The reason for this is to prevent the reflected light, when the zero-order light L0 is reflected by the diffuser 10, from entering the diffraction grating 7 and becoming stray light, which would adversely affect the measurement. However, the diffuser 10 may also be disposed so that the direction of its normal line coincides with the direction of the optical axis La of the zero-order light L0.

[0025] The above-mentioned slit member 5, concave mirror 6, diffraction grating 7, light-receiving sensor 8, observation light source 9, and diffuser plate 10 are housed in a single light-shielding case 11. The light to be measured L from the sample 100 that has passed through the light-receiving optical system 3 is guided into the light-shielding case 11 and reaches the slit 51 of the slit member 5, where it forms an image.

[0026] Additionally, auxiliary light sources 12, such as LEDs, are disposed at predetermined positions around integrating sphere 2. When the measurement position of sample 100 is confirmed by turning on observation light source 9, auxiliary light sources 12 illuminate the inner surface of integrating sphere 2, thereby illuminating the entire sample 100 placed in measurement aperture 21 with multiple diffused light from the inner surface of integrating sphere 2 and making the pointer easier to see.

[0027] Furthermore, in the integrating sphere 2, an observation opening 25 is formed at a position where the sample 100 can be observed, and a camera 26 is disposed outside the observation opening 25. Note that it is desirable that the observation opening 25 be closed during color measurement.

[0028] In the spectrophotometer 1 shown in Figure 1, to confirm the observation position on the measurement surface of sample 100, first turn on the observation light source 9 and auxiliary light source 12. Light emitted from the observation light source 9 is diffused by the diffuser plate 10, and travels as diffused light toward and is reflected by the diffraction grating 7. The diffused light reflected by the diffraction grating 7 is reflected by the concave mirror 6 and illuminates the slit 51 in the slit member 5. Because the size of the luminous flux of the diffused light is larger than the size of the luminous flux of the observation light source 9, the entire slit 51 is uniformly illuminated by the diffused light. In other words, the same effect as when the observation light source is enlarged can be achieved without enlarging it.

[0029] The diffused light that has passed through the slit 51 passes through the light-receiving optical system 3, which includes the light-receiving lens 31, and further passes through the light-receiving opening 22 to enter the integrating sphere 2, where it forms an image of the slit 51 on the measurement surface of the sample 100 to be measured. The appearance of the measurement surface of the sample 100, including this image, is photographed by the camera 26 through the observation opening 25. The image photographed by the camera 26 is displayed on a display unit (not shown). The appearance of the image is as described in FIG. 6 .

[0030] When the diffused light passes through the slit 51, the entire slit 51 is uniformly illuminated by the diffused light, so the image of the slit 51 formed on the measurement surface of the sample 100 has uniform brightness without unevenness in the amount of light. Therefore, the observer can clearly observe the measurement position by using the image of the slit 51 on the measurement surface with no unevenness in the amount of light as a pointer.

[0031] 2 to 5 are diagrams for explaining the specific structure for attaching the observation light source 9 and the diffusion plate 10. FIG.

[0032] 2A, the observation light source 9 and the diffusion plate 10 are attached to a light-shielding unit 200. The light-shielding unit 200 corresponds to a light-shielding wall provided between the observation light source 9 and the light-receiving sensor 8 to prevent the observation light from the observation light source 9 from entering the light-receiving sensor 8.

[0033] As shown in Figures 2(B), 3 and 4, the light-shielding unit 200 is attached to the peripheral wall 111 of the light-shielding case 11. Although only the peripheral wall 111 of the light-shielding case 11 is shown in Figures 2(B), 3 and 4, both sides of the peripheral wall 111 of the light-shielding case 11 in the width direction are light-shielded by covers. Also, reference numeral 7 denotes a diffraction grating, and reference numeral 8 denotes a light-receiving sensor.

[0034] 2A and 2B, the light-shielding unit 200 includes a rectangular large-diameter portion 201 and a unit main body portion 202 that bulges downward from the bottom surface of the large-diameter portion 201. The unit main body portion 202 is inclined so that a surface 205 on the diffraction grating 7 side and a surface 206 on the light-receiving sensor 8 side approach each other as they go downward. The surface 206 on the light-receiving sensor 8 side is formed in a stepped shape. The reason why the surface 206 on the light-receiving sensor 8 side is formed in a stepped shape will be described later.

[0035] A rectangular recess 203 is formed on the upper surface of the light-shielding unit 200. The size of the rectangular recess 203 is set to be smaller than the large-diameter portion 201 of the light-shielding unit 200. In addition, a cylindrical space 204 is formed obliquely penetrating the unit main body 202 of the light-shielding unit 200, and communicating between a surface 205 of the light-shielding unit 200 on the diffraction grating 7 side and the bottom surface of the rectangular recess 203.

[0036] In the light-shielding unit 200, except for the surface 205 on the diffraction grating 7 side and the surface 206 on the light-receiving sensor 8 side, the other two vertical surfaces 207, 208 (shown in Figure 5) are formed with second light-shielding protrusions 209, 210 (shown in Figure 5) that extend vertically and protrude perpendicularly to each surface 207, 208.

[0037] Mounting holes 112 for mounting the light-shielding unit 200 are formed in the peripheral wall 111 of the light-shielding case 11. Outwardly extending notches 112a and 112b are formed on two opposing sides of the mounting hole 112 in the width direction of the light-shielding case 11.

[0038] The light-shielding unit 200 is attached to the peripheral wall 111 of the light-shielding case 11 in the following manner. That is, the light-shielding unit 200 is fitted into the mounting hole 112 of the light-shielding case 11 with the second light-shielding protrusions 209 and 210 of the light-shielding unit 200 positioned in the notches 112a and 112b of the mounting hole 112. Then, with the lower surface of the large-diameter portion 201 of the light-shielding unit 200 abutting against the peripheral edge of the mounting hole 112, the light-shielding unit 200 is fixed to the peripheral wall 111 of the light-shielding case 11 with screws (not shown) or the like. In this state, the cylindrical space 204 is positioned on the optical axis La of the zero-order light of the diffraction grating 7, and most of the zero-order light L0 of the diffraction grating 7 passes through the cylindrical space 204 when measuring the sample 100.

[0039] Furthermore, a first light-shielding protrusion 220 is formed on the end of the large-diameter portion 201 of the light-shielding unit 200 on the diffraction grating 7 side, and extends parallel to the outer surface of the peripheral wall portion 111 of the light-shielding case 11 when the light-shielding unit 200 is attached to the light-shielding case 11. The role of the first light-shielding protrusion 220 will be described later.

[0040] Furthermore, two triangular pyramidal incident prevention members 113, 114 tapering downward are formed at a distance from each other on the underside of the peripheral wall 111 of the light-shielding case 11 on both sides in the width direction of the mounting hole 112 (the width direction of the peripheral wall 111). The light-shielding unit 200 is attached with the lower part of the unit body 202 fitted into the space between the two incident prevention members 113, 114, as shown in Fig. 3. In this embodiment, the light-shielding unit 200 and the two incident prevention members 113, 114 are close to each other, but they may also abut against each other.

[0041] During color measurement, most of the zero-order light traveling from the diffraction grating 7 toward the light-shielding unit 200 passes through the cylindrical space 204 of the light-shielding unit 200. However, if the incidence prevention members 113 and 114 were not present, some of the light would be reflected by the light-shielding unit 200 or would directly enter the light-receiving sensor 8. There is also a risk that the light reflected by the light-shielding unit 200 will return to the diffraction grating 7. The zero-order light that enters the light-receiving sensor 8 will reduce the measurement accuracy. Furthermore, the zero-order light that returns to the diffraction grating 7 will be reflected by the diffraction grating 7 and travel toward the light-receiving sensor 8, which may reduce the measurement accuracy.

[0042] Therefore, incidence prevention members 113 and 114 are provided to block the zero-order light incident on the light-receiving sensor 8. Furthermore, light that may be reflected by the light-shielding unit 200 and return to the diffraction grating 7 is reflected in a direction other than the diffraction grating 7 by the inclined surfaces 113b and 114b of the incidence prevention members 113 and 114, which are inclined at a predetermined angle. Note that the surface 205 of the light-shielding unit 200 facing the diffraction grating 7 is also inclined at approximately the same angle as the inclined surfaces 113b and 114b of the incidence prevention members 113 and 114. Therefore, even if light outside the cylindrical space 204 of the zero-order light is irradiated onto the surface 205 of the light-shielding unit 200 or the inclined surfaces 113b and 114b of the incidence prevention members 113 and 114, it is reflected in a direction other than the light-receiving sensor 8 or the diffraction grating 7. This prevents the light from entering the light-receiving sensor 8 or returning to the diffraction grating 7.

[0043] As described above, when the light-shielding unit 200 is attached to the light-shielding case 11, the second light-shielding protrusions 209, 210 are fitted into the notches 112a, 112b in the mounting hole 112 of the light-shielding case 11. Furthermore, as shown in FIG. 5 , the surfaces of these second light-shielding protrusions 209, 210 facing the diffraction grating 7 are in close proximity to the vertical surfaces 113a, 114a of the incident prevention members 113, 114 facing the light-receiving sensor 8. The second light-shielding protrusions 209, 210 may be in contact with the vertical surfaces 113a, 114a of the incident prevention members 113, 114. The role of the second light-shielding protrusions 209, 210 will be described later.

[0044] A diffuser plate 10 is disposed at the bottom of the rectangular recess 203 of the light-shielding unit 200. The central portion of the lower surface of the diffuser plate 10 is exposed at the top of the cylindrical space 204. A substrate 300 having an observation light source 9 such as an LED is fixed to the upper surface of the light-shielding unit 200 in a manner that covers the rectangular recess 203.

[0045] In this embodiment, the light shielding unit 200 is made of resin, ensuring insulation, and the substrate 300 can be attached directly to the light shielding unit 200. Furthermore, by making the light shielding unit 200 out of resin, there is no need to provide a separate insulating member, which also has the effect of reducing the number of parts.

[0046] The observation light source 9 attached to the shading unit 200 has a light-emitting portion on the underside of the substrate 300, and emits light downward from the light-emitting portion. The emitted light is diffused by the diffusion plate 10 to become diffused light, and this diffused light passes through the cylindrical space 204 and heads toward the diffraction grating 7. Therefore, the shading unit 200 prevents the observation light emitted from the observation light source 9 from entering the light-receiving sensor 8.

[0047] The diffused light generated by the diffuser plate 10 travels in the opposite direction to the direction of the zero-order light of the diffraction grating 7, whose optical axis La is shown in Figures 3 and 4. In other words, the diffused light traveling toward the diffraction grating 7 is reflected by the diffraction grating 7, then reflected by the concave mirror 6, and travels toward the slit member 5. The slit 51 of the slit member 5 is uniformly illuminated, and an image of the slit 51 without light unevenness is formed on the measurement surface of the sample 100, just like in the case of the spectrophotometer 1 according to the embodiment shown in Figure 1.

[0048] As described above, in this embodiment, the observation light source 9 and the diffuser plate 10 are housed in the light-shielding unit 200, which is attached to the light-shielding case 11. This not only prevents the observation light from the observation light source 9 from entering the light-receiving sensor 8, but also makes it easy to position the observation light source 9 and the diffuser plate 10 relative to the diffraction grating 7, etc. Furthermore, attachment of the observation light source 9 and the diffuser plate 10 is also simple.

[0049] However, if stray light occurs inside the light-shielding case 11, it will have an adverse effect on the light-receiving sensor 8, making it impossible to perform highly accurate color measurement. Therefore, in this embodiment, the following measures are taken to prevent stray light: [1] Arrangement of the diffuser plate 10 During normal color measurement, the zero-order light from the diffraction grating 7 is irradiated onto the diffuser plate 10, and if the reflected light is diffused inside the light-shielding case 11, it may become stray light.

[0050] 1, in this embodiment, the diffuser plate 10 housed in the rectangular recess 203 of the light-shielding unit 200 is disposed with its normal line tilted with respect to the optical axis La of the zero-order light. The above-described arrangement state is automatically realized simply by housing the diffuser plate 10 in the rectangular recess 203 of the light-shielding unit 200. [2] There is a risk that the measured light L reflected by the staircase-shaped diffraction grating 7 and directed toward the light-receiving sensor 8 will be reflected by the light-receiving sensor 8, and that this reflected light will be further reflected by the light-shielding unit 200 and directed toward the light-receiving sensor 8 again.

[0051] Therefore, as described above, in this embodiment, the surface 206 of the unit body 202 of the light-shielding unit 200 facing the light-receiving sensor 8 is formed in a stepped shape to scatter reflected light from the light-receiving sensor 8 toward the surface 206 of the light-shielding unit 200. This prevents light reflected by the light-shielding unit 200 from returning to the light-receiving sensor 8. [3] First Light-Shielding Projection 220 Because the light-shielding unit 200 is mounted by fitting into the mounting hole 112 of the light-shielding case 11, there is a risk of external light entering the light-shielding case 11 through a gap between the light-shielding unit 200 and the light-shielding case 11. In particular, high-brightness light from an illumination light source 4, such as a Xe lamp, which is turned on during color measurement, arrives from the direction indicated by arrow A in FIGS. 3 and 4 . Therefore, in order to prevent light, particularly from the illumination light source 4, from entering the light-shielding case 11, the light-shielding unit 200 is provided with a first light-shielding projection 220 that projects toward the illumination light source 4. This first light-shielding protrusion 220 protrudes like a canopy and shields the gap between the light-shielding unit 200 and the light-shielding case 11, thereby preventing light from the illumination light source 4 from entering the light-shielding case 11. [4] Second light-shielding protrusions 209, 210 During color measurement, the zero-order light reflected by the diffraction grating 7 heads toward the surface 205 of the light-shielding unit 200 facing the diffraction grating 7. Most of the zero-order light passes through the cylindrical space 204 of the light-shielding unit 200. Some heads toward the inclined surface 205 of the light-shielding unit 200 and the incident prevention members 113, 114. However, the incident prevention members 113, 114 prevent the light from heading toward the light-receiving sensor 8. Furthermore, the inclined surfaces 113b, 114b of the incident prevention members 113, 114 and the inclined surface 205 of the light-shielding unit 200 also prevent reflection toward the diffraction grating 7. However, there is a risk that the zero-order light may pass through the gap between the two incidence prevention members 113 and 114 of the light-shielding case 11 and the light-shielding unit 200 and leak toward the light-receiving sensor 8 side.

[0052] Therefore, when the light-shielding unit 200 is attached, the surfaces of the second light-shielding protrusions 209, 210 on the light-shielding unit 200 facing the diffraction grating 7 are adjacent to or in contact with the vertical surfaces 113a, 114a of the incident prevention members 113, 114 facing the light-receiving sensor 8. This prevents zero-order light reflected by the diffraction grating 7 from passing through the gaps between the incident prevention members 113, 114 and the light-shielding unit 200 and leaking to the light-receiving sensor 8. [5] Light-shielding unit 200 In this embodiment, the light-shielding unit 200 has a complex shape and is manufactured using a 3D printer. However, if the light-shielding unit 200 were manufactured using a powder sintering method similar to the surface condition of the inner surface of the light-shielding case 11, there is a risk that light generated by the illumination light source 4 would pass through the light-shielding unit 200 and enter the interior of the light-shielding case 11. Therefore, an additive manufacturing method is used to manufacture the light-shielding unit using a 3D printer. [6] Mounting substrate 300 for observation light source 9 There is a risk that light generated by the illumination light source 4 may pass through the substrate 300 on which the observation light source 9 is mounted. For this reason, a light-shielding treatment is applied to the substrate 300. As an example of the light-shielding treatment, in this embodiment, a black resist and a solid pattern are formed on the substrate 300.

[0053] The above stray light countermeasures [1] to [5] are not necessarily required, but it is advisable to implement at least one, and preferably all, of them.

[0054] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, although the case where the light-shielding unit 200 is formed separately from the light-shielding case 11 has been described, the portion corresponding to the light-shielding unit 200 may be formed integrally with the light-shielding case 11. In this case, a thick portion is formed in the light-shielding case 11, and portions corresponding to the light-shielding unit main body 202 and the like are machined into this thick portion. When the light-shielding unit 200 is formed integrally with the light-shielding case 11, measures [3], [4], and [5] of the above-described measures for preventing stray light are unnecessary.

[0055] In addition, the spectrophotometer 1 is exemplified as a type in which illumination light is irradiated onto the sample 100 via the integrating sphere 2 and the color of the reflected light is measured. However, the present invention can also be applied to a spectrophotometer that measures the color of a luminescent sample without using the integrating sphere 2.

[0056] This application claims priority from Japanese Patent Application No. 2024-145052, filed on August 27, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0057] The present invention can be used in a spectrophotometer that can observe a measurement position on a sample surface when measuring the sample.

[0058] REFERENCE SIGNS LIST 1 spectrophotometer 2 integrating sphere 21 sample opening 22 light-receiving opening 23 trap hole 24 trap 25 observation opening 26 camera 3 light-receiving optical system 4 illumination light source 5 slit member 51 slit 6 concave mirror 7 diffraction grating 8 light-receiving sensor 9 observation light source 10 diffuser plate 11 light-shielding case 12 auxiliary light source 100 sample 111 peripheral wall 112 mounting hole 112a, 112b notch 113, 114 incidence prevention member 113b, 114b inclined surface 200 light-shielding unit 201 large diameter portion 202 unit body 203 rectangular recess 204 cylindrical space 206 stepped surface 209, 210 second light-shielding protrusion 220 first light-shielding protrusion 300 Substrate L Light to be measured L0 0th order light La Optical axis of 0th order light

Claims

1. A spectrophotometer comprising: a light-receiving optical system that receives and images measured light from a sample to be measured; a slit member having a slit positioned at the imaging position of the light-receiving optical system; spectroscopic means that disperses the measured light that has passed through the slit; a sensor that receives the light dispersed by the spectroscopic means and outputs a spectral signal of the measured light; an observation light source that emits observation light and is positioned in the optical path of the zero-order light of the spectroscopic means; and a diffusion member that is positioned between the observation light source and the spectroscopic means and diffuses the light emitted from the observation light source and generates diffused light that is directed toward the spectroscopic means, wherein the light-receiving optical system forms an image of a slit on the measurement surface of the sample, illuminated by the diffused light that is directed toward the spectroscopic means and reflected by the spectroscopic means.

2. The spectrophotometer according to claim 1, further comprising: an integrating sphere having a measurement aperture; an illumination light source that generates the light to be measured by illuminating the sample placed in the measurement aperture with light diffused by the integrating sphere; and an auxiliary light source that emits light together with the observation light source and illuminates the sample.

3. A spectrophotometer according to claim 1 or 2, further comprising a light-shielding wall between the observation light source and the sensor to prevent the observation light from the observation light source from entering the sensor.

4. A spectrophotometer as described in claim 3, wherein the light-shielding wall is formed by a light-shielding unit having a cylindrical space, the light-shielding unit houses the diffusing member and the observation light source, and the diffused light is directed toward the spectroscopic means through the cylindrical space.

5. The spectrophotometer according to claim 3, wherein the wall surface of the light-shielding wall on the sensor side is formed in a stepped shape.

6. The spectrophotometer according to claim 3, wherein the observation light source is mounted on a substrate, and the substrate is subjected to a light-shielding treatment.

7. A spectrophotometer according to claim 1 or 2, wherein the diffusing member is disposed with its normal tilted relative to the optical axis of the zero-order light.

8. A spectrophotometer as set forth in claim 4, wherein the slit member, the spectroscopic means, and the sensor are housed in a light-shielding case, the light-shielding unit is attached by being fitted into a mounting hole in the light-shielding case, and the light-shielding unit is formed with a first light-shielding protrusion for preventing stray light from outside the light-shielding case from entering the light-shielding case.

9. A spectrophotometer as described in claim 4, wherein the slit member, the spectroscopic means, and the sensor are housed in a light-shielding case, the light-shielding unit is attached by being fitted into a mounting hole in the light-shielding case, the light-shielding case is formed with an incident prevention member that prevents the zeroth-order light from entering the sensor during color measurement, and the light-shielding unit is formed with a second light-shielding protrusion that prevents the zeroth-order light from the spectroscopic means from slipping through a gap between the incident prevention member and the light-shielding unit to the sensor side.

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