Spectrophotometer

Abstract

To irradiate a position to be measured with observation light without providing a large space inside a spectrophotometer, thereby making it possible to easily know the position to be measured.SOLUTION: The spectrophotometer includes a measurement aperture, a light reception optical system that forms light to be measured from a position of a sample to be measured that is incident through the measurement aperture to generate the light to be measured that is formed into the image, a sensor that receives the light to be measured and outputs a signal expressing optical characteristics, an observation light source that emits observation light to illuminate a position of a sample to be measured opposing the measurement aperture through the measurement aperture when observing the position to be measured, and an auxiliary light source that emits illumination light for illuminating a surface of the sample opposing the measurement aperture through the measurement aperture during observation of the position of the sample to be measured through the measurement aperture at the same time as the observation light emission by the observation light source.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a spectrophotometer. [Background technology]

[0002] When the measurement range of a spectrophotometer that measures a spectral spectrum is small, even if the measurement position is only slightly shifted from the intended position, the measured spectral spectrum may differ significantly from the spectral spectrum of light from the intended position. For this reason, when the measurement range of a spectrophotometer is small, it is desirable to be able to observe the measurement position before measurement and to align the measurement position with the intended position before measurement. The technology described in Patent Document 1 is an example of a technology that makes this possible in a spectroscope.

[0003] In the technology described in Patent Document 1, when observation light is injected, the shutter is closed. An LED irradiates the observation light toward the shutter, which reflects the irradiated observation light toward an objective lens, which then forms an image of the reflected light on the surface of the object to be measured. The measurement site is identified from the position of the light image formed on the surface of the object to be measured. When measurement is to be performed, the shutter is opened, and light that has passed through a slit mirror is guided to a light receiving unit (paragraphs 0027-0031). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-288150 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional techniques such as that described in Patent Document 1, a large space must be provided inside the spectrophotometer to accommodate a mechanism for irradiating the measurement position with observation light. For example, in the technique described in Patent Document 1, a large space must be provided inside the spectroscope to accommodate a slit mirror or the like inside the spectroscope.

[0006] The invention described below aims to solve this problem. The problem that the invention described below aims to solve is to make it possible to irradiate the measurement position with observation light without providing a large space inside the spectrophotometer, and to make it possible to easily determine the measurement position. [Means for solving the problem]

[0007] The invention described below relates to spectrophotometers.

[0008] In the first invention described below, The illumination optical system includes an illumination light source and an integrating sphere having a measurement aperture, and illuminates a sample placed opposite the measurement aperture with diffused light. The light to be measured, which is incident from the position to be measured on the sample through the measurement aperture, is imaged by the light receiving optical system, thereby generating the imaged light to be measured.

[0009] The spectroscope separates the light to be measured that has been imaged by the light receiving optical system. The sensor is Spectroscopic It receives the light to be measured and outputs a signal representing the optical characteristics.

[0010] The observation light source emits observation light for illuminating the measurement position on the sample facing the measurement aperture through the measurement aperture when observing the measurement position.

[0011] The auxiliary light source is used to illuminate the surface of the sample facing the measurement aperture through the measurement aperture when observing the position to be measured through the measurement aperture. Light The bright light is emitted simultaneously with the emission of the observation light by the observation light source. The camera captures an image of the surface of the sample facing the measurement aperture through the measurement aperture. The observation light is imaged on the sample by the light receiving optical system, illuminating the measurement position on the sample, the measurement position illuminated by the observation light is a part of the surface of the sample illuminated by the illumination light, The camera captures an image of the surface of the sample facing the measurement opening including the illuminated measurement position, using an optical path different from the optical path of the light receiving optical system. [Effects of the Invention]

[0012] According to the invention described below, it becomes possible to irradiate the measurement position with observation light without providing a large space inside the spectrophotometer, and it becomes possible to easily know the measurement position.

[0013] The objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram illustrating a spectrophotometer according to a first embodiment. [Figure 2] 2 is a schematic diagram illustrating a cross section of a spectroscope provided in the spectrophotometer of the first embodiment. FIG. [Figure 3] 2 is a schematic diagram illustrating a partial cross section of a drive mechanism for a spectroscope and an observation light source provided in the spectrophotometer of the first embodiment. FIG. [Figure 4] 2 is a schematic diagram illustrating an observation light source that can replace the observation light source provided in the spectrophotometer of the first embodiment. FIG. [Figure 5] FIG. 10 is a schematic diagram illustrating a spectrophotometer according to a second embodiment. [Figure 6] FIG. 10 is a perspective view illustrating the arrangement of a diffraction grating in a spectrophotometer according to a second embodiment. [Figure 7] FIG. 10 is a perspective view illustrating an arrangement of a diffraction grating that is compared with the arrangement of a diffraction grating in the spectrophotometer of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1. First embodiment 1.1 Spectrophotometer Fig. 1 is a schematic diagram illustrating a spectrophotometer according to a first embodiment. Fig. 2 is a schematic diagram illustrating a cross section of a spectroscope included in the spectrophotometer according to the first embodiment. Fig. 3 is a schematic diagram illustrating a partial cross section of the spectroscope and a driving mechanism for an observation light source included in the spectrophotometer according to the first embodiment.

[0016] Fig. 2 illustrates a cross section taken along line AA in Fig. 3. Fig. 3 illustrates a partial cross section taken along line BB in Fig. 2.

[0017] 1 includes an illumination optical system 1020, a light receiving optical system 1021, a spectrometer 1022, a controller 1023, and an operation unit 1024. The spectrophotometer 1000 may include components other than these components.

[0018] The spectrophotometer 1000 is a spectrophotometer for measuring object color with d:8 geometry. Therefore, in the spectrophotometer 1000, an illumination optical system 1020 illuminates a sample with diffused light. A light-receiving optical system 1021 receives the light to be measured that is emitted from the sample in a direction that forms an 8° angle with the normal direction of the surface, and guides the light to a spectroscope 1022. The spectroscope 1022 measures the spectrum of the light to be measured that has been guided by the light-receiving optical system 1021.

[0019] The illumination optical system 1020 includes an illumination light source 1040 and an integrating sphere 1041. The illumination optical system 1020 may include components other than these components. The light-receiving optical system 1021 includes a light-receiving lens 1060. The light-receiving optical system 1021 may include components other than the light-receiving lens 1060. As shown in FIGS. 1, 2, and 3, the spectrometer 1022 includes a slit plate 1080, a lens 1081, a diffraction grating 1082, a line sensor 1083, an observation light source 1084, and an insertion / removal mechanism 1085. The spectrometer 1022 may include components other than these components. A slit 1100 is formed in the slit plate 1080. The slit plate 1080, which is a plate-shaped slit-forming element, may be replaced with a non-plate-shaped slit-forming element. The diffraction grating 1082 may be replaced with a wavelength dispersion element other than the diffraction grating 1082. For example, the diffraction grating 1082 may be replaced with a prism. The line sensor 1083 having a plurality of photoelectric conversion elements arranged in the wavelength dispersion direction may be replaced with a sensor other than the line sensor 1083. For example, the line sensor 1083 may be replaced with a sensor having a single photoelectric conversion element. In this case, a scanning mechanism is provided that scans the sensor in the wavelength dispersion direction. Alternatively, a scanning mechanism is provided that rotates and scans the wavelength dispersion element in the wavelength dispersion direction.

[0020] 1.2 Spectroscopic Measurement The measurement of the optical spectrum is started in response to the controller 1023 detecting an operation to start the measurement performed on the operation unit 1024. The trigger for starting the measurement may be something other than an operation to start the measurement performed on the operation unit 1024. For example, the trigger for starting the measurement may be a signal to start the measurement input from a device communicatively connected to the spectrophotometer 1000.

[0021] When measuring the optical spectrum, the insertion / removal mechanism 1085 retracts the observation light source 1084 to outside the measurement optical path 1120 under the control of the controller 1023. The retraction of the observation light source 1084 is performed by the rotation mechanism 1090 rotating an arm 1091 to which the observation light source 1084 is attached around a rotation center 1092.

[0022] During the measurement of the optical spectrum, the illumination light source 1040 emits illumination light for illuminating the sample under the control of the controller 1023 .

[0023] The emitted illumination light passes through opening 1140 formed in the side surface of integrating sphere 1041 and enters space 1160 formed inside integrating sphere 1041, and is diffusely and multiple-reflected by diffuse reflection surface 1180 surrounding space 1160. As a result, the illumination light becomes uniformly diffused illumination light.

[0024] The uniformly diffused illumination light is emitted from measurement aperture 1200 formed in integrating sphere 1041, illuminates an area facing measurement aperture 1200, and is reflected by the surface of a sample placed at measurement position 1220. As a result, measurement light 1240 is generated from measurement position 1220.

[0025] When performing measurements with specular reflection light removed, the specular reflection light is removed by opening openable trap 1260 formed in integrating sphere 1041 .

[0026] The generated measured light 1240 is imaged onto the slit 1100 by the light receiving lens 1060. This generates imaged measured light 1280. The light receiving lens 1060 is movable in the direction of its optical axis. By moving the light receiving lens 1060 in the direction of its optical axis, the size of the measured region can be changed.

[0027] The imaged measured light 1280 passes through the slit 1100. This generates measured light 1300 that travels along a measurement optical path 1120 between the slit 1100 and the diffraction grating 1082.

[0028] Measured light 1300 traveling along measurement optical path 1120 is guided by lens 1081 and diffracted by diffraction grating 1082. This generates diffracted light including −1st-order diffracted light 1320. Since the measured light 1300 traveling along measurement optical path 1120 is wavelength-dispersed by diffraction, the −1st-order diffracted light 1320 is wavelength-dispersed light.

[0029] The generated −1st-order diffracted light 1320 is received by the line sensor 1083. The line sensor 1083 may receive diffracted light other than the −1st-order diffracted light 1320.

[0030] The line sensor 1083 outputs a signal representing a spectrum corresponding to the received −1st-order diffracted light 1320 .

[0031] 1.3 Observation of the measurement position Spectrophotometer 1000 has a function of irradiating observation light onto measurement position 1220. An operator of spectrophotometer 1000 can observe measurement position 1220 by visually recognizing a highlight portion that appears when observation light is irradiated onto measurement position 1220 through finder hole 1340 formed in integrating sphere 1041.

[0032] When observing the measurement position 1220, the insertion / removal mechanism 1085 inserts the observation light source 1084 into the measurement light path 1120 under the control of the controller 1023. The observation light source 1084 is inserted by the rotation mechanism 1090 rotating the arm 1091 to which the observation light source 1084 is attached around the rotation center 1092. When the observation light source 1084 is inserted into the measurement light path 1120, the light-emitting surface of the observation light source 1084 faces the slit 1100, and the observation light source 1084 can emit observation light toward the slit 1100.

[0033] When observing the measurement position 1220 , the observation light source 1084 emits observation light toward the slit 1100 under the control of the controller 1023 .

[0034] The emitted observation light passes through a slit 1100 and is focused into an image by a light receiving lens 1060 .

[0035] Slit 1100 is disposed at a position optically conjugate with measurement position 1220. Therefore, when observation light source 1084 emits observation light, an image of slit 1100 is formed on the surface of the sample. Since the position where the image of slit 1100 is formed is measurement position 1220, the operator can observe measurement position 1220 by visually recognizing the image of slit 1100 through finder hole 1340 formed in integrating sphere 1041.

[0036] The fact that the slit 1100 and the measurement position 1220 are optically conjugate contributes to preventing the position at which the image of the slit 1100 is formed from shifting even if the position at which the observation light source 1084 is disposed shifts. Furthermore, inserting the observation light source 1084 into the measurement light path 1120 using the insertion / removal mechanism 1085 makes it possible to position the observation light source 1084 near the slit 1100, contributing to increasing the amount of observation light that can be used as pointer light.

[0037] According to the spectrophotometer 1000 of the first embodiment, it is possible to irradiate the measurement position 1220 with observation light that serves as pointer light without providing a large space between the slit 1100 and the diffraction grating 1082 inside the spectrophotometer 1000, and it is therefore possible to easily observe the measurement position 1220. Furthermore, according to the spectrophotometer 1000 of the first embodiment, no additional member such as a mirror is required.

[0038] 1.4 Observation light source The observation light source 1084 includes a light-emitting diode (LED) that emits observation light. The LED is preferably a thin LED. Although a light source other than a light-emitting diode may be used to emit the observation light, using an LED to emit the observation light allows the spectrophotometer 1000 to be made more compact. Furthermore, using an LED to emit the observation light reduces the power consumption of the observation light source 1084, thereby extending its lifespan.

[0039] FIG. 4 is a schematic diagram illustrating an observation light source that can replace the observation light source provided in the spectrophotometer of the first embodiment.

[0040] The observation light source 1380 shown in FIG. 4 can replace the observation light source 1084 shown in FIG. 1 and includes LEDs 1400, 1401, and 1402. The LEDs 1400, 1401, and 1402 emit light 1420, 1421, and 1422, respectively. The light 1420, 1421, and 1422 have different colors. The three LEDs consisting of the LEDs 1400, 1401, and 1402 may be replaced with two LEDs or four or more LEDs. At least some of the LEDs 1400, 1401, and 1402 may be replaced with light sources other than LEDs.

[0041] When the observation light source 1084 is replaced with the observation light source 1380, the controller 1023 and the operation unit 1024 operate as a switching mechanism that switches the light to be used as the observation light among the lights 1420, 1421, and 1422. That is, the controller 1023 detects an operation performed on the operation unit 1024 to select a color, and controls the LEDs 1400, 1401, and 1402 so that the observation light source 1380 emits light of a color corresponding to the selected color. This allows the color of the observation light to be selected according to the color of the surface of the sample, making it easier to observe the measurement position 1220. The color of the sample may be provisionally measured when observing the measurement position 1220, and the color of the light emitted by the observation light source 1380 may be determined using the results of the provisional measurement.

[0042] 1.5 Illumination light emission when observing the measurement position In the object color spectrophotometer 1000, the gap between the illumination optical system 1020 and the sample is often shielded by a target mask or the like to prevent external light other than the illumination light from entering the gap. When the gap is shielded, simply irradiating the measurement position 1220 with observation light makes it difficult to see anything other than the measurement position 1220, making it impossible to determine which part of the sample surface the measurement position 1220 is located on. For this reason, the illumination light source 1040 may be used as an auxiliary light source when observing the measurement position 1220, and the illumination light source 1040 may be configured to emit illumination light under the control of the controller 1023 when observing the measurement position 1220. This makes it possible to see anything other than the measurement position 1220, thereby determining which part of the sample surface the measurement position 1220 is located on.

[0043] When illumination light is emitted during observation of the measurement position 1220, the controller 1023 and the operation unit 1024 function as an adjustment mechanism that adjusts the amount of illumination light. That is, the controller 1023 detects an operation performed on the operation unit 1024 to set the amount of illumination light, and controls the illumination light source 1040 so that the illumination light source 1040 emits illumination light having an amount of light corresponding to the selected amount of light.

[0044] 1.6 Other The above configuration for irradiating the measurement position 1220 with observation light may be employed in a spectrophotometer other than the object color spectrophotometer 1000 having d:8 geometry. The spectral spectrum of the transmitted light that has passed through the sample may be measured.

[0045] 2. Second embodiment 2.1 Main differences between the first and second embodiments The main difference between the first and second embodiments is that in the first embodiment, an observation light source 1084 is inserted into the measurement light path 1120 when observing the measurement position 1220, whereas in the second embodiment, the observation light source is always placed on the optical path of the zero-order light generated by reflecting the measurement light off the diffraction grating. The configuration of the spectrophotometer 1000 of the first embodiment or a variation thereof may be adopted in the spectrophotometer of the second embodiment, as long as it does not prevent the adoption of the configuration that causes this main difference.

[0046] 2.2 Spectrophotometer FIG. 5 is a schematic diagram illustrating a spectrophotometer according to the second embodiment.

[0047] The spectrophotometer 2000 shown in FIG. 5 includes an illumination optical system 2020, a light receiving optical system 2021, a spectrometer 2022, a controller 2023, an operation unit 2024, and a camera 2025.

[0048] The illumination optical system 2020 includes an illumination light source 2040 and an integrating sphere 2041. The light-receiving optical system 2021 includes a light-receiving lens 2060. The spectroscope 2022 includes a slit plate 2080, a lens 2081, a diffraction grating 2082, a line sensor 2083, and an observation light source 2084. A slit 2100 is formed in the slit plate 2080.

[0049] 2.3 Spectroscopic Measurement When measuring the optical spectrum, the illumination light source 2040 emits illumination light for illuminating the sample under the control of the controller 2023 .

[0050] The emitted illumination light passes through opening 2140 formed in the side surface of integrating sphere 2041 and enters space 2160 formed inside integrating sphere 2041, and is diffusely and multiple-reflected by diffuse reflection surface 2180 surrounding space 2160. As a result, the illumination light becomes uniformly diffused illumination light.

[0051] The uniformly diffused illumination light is emitted from measurement aperture 2200 formed in integrating sphere 2041, illuminates an area facing measurement aperture 2200, and is reflected by the surface of a sample placed at measurement position 2220. As a result, measurement light 2240 from measurement position 2220 is generated.

[0052] The generated light to be measured 2240 is imaged by the light receiving lens 2060. As a result, imaged light to be measured 2280 is generated.

[0053] The imaged measured light 2280 passes through the slit 2100. This generates measured light 2300 that travels along a measurement optical path 2120 between the slit 2100 and the diffraction grating 2082.

[0054] Measured light 2300 traveling along measurement optical path 2120 is guided by lens 2081, and diffracted and reflected by diffraction grating 2082. Diffraction generates diffracted light including −1st-order diffracted light 2320. Reflection generates 0th-order light 2321. Since measured light 2300 traveling along measurement optical path 2120 is wavelength-dispersed by diffraction, −1st-order diffracted light 2320 is wavelength-dispersed light.

[0055] The generated −1st order diffracted light 2320 is received by the line sensor 2083 .

[0056] The line sensor 2083 outputs a signal representing a spectrum corresponding to the received −1st-order diffracted light 2320 .

[0057] 2.4 Observation of the measurement position The spectrophotometer 2000 has a function of irradiating the measurement position 2220 with observation light. The operator can observe the measurement position 2220 by visually recognizing bright spots, bright lines, etc. that appear when the observation light is irradiated onto the measurement position 2220 through a finder hole 2340 formed in the integrating sphere 2041.

[0058] The observation light source 2084 is disposed on the optical path of the zero-order light 2321. Because the optical path of the zero-order light 2321 is outside the measurement optical path 2120, it is not necessary to retract the observation light source 2084 when measuring the spectrum. Therefore, it is not necessary to make the observation light source 2084, the mirror that reflects the observation light, etc. movable, and no drive mechanism is required to move the observation light source 2084, the mirror that reflects the observation light, etc.

[0059] When observing the measurement position 2220 , the observation light source 2084 emits observation light toward the diffraction grating 2082 under the control of the controller 2023 .

[0060] The emitted observation light is reflected by the diffraction grating 2082 , passes through the slit 2100 , and is focused into an image by the light receiving lens 2060 .

[0061] When observation light source 2084 emits observation light, an image of slit 2100 is formed on the surface of the sample. Since the position where the image of slit 2100 is formed is measurement position 2220, the operator can observe measurement position 2220 by visually checking the image of slit 2100 through finder hole 2340 formed in integrating sphere 2041.

[0062] In the second embodiment, unlike the first embodiment, it is not necessary to place the slit 2100 at a position optically conjugate with the position to be measured 2220 .

[0063] According to the spectrophotometer 2000 of the second embodiment, observation light can be irradiated onto the measurement position 2220 without providing a large space inside the spectrophotometer 2000, making it possible to easily observe the measurement position 2220. Furthermore, according to the spectrophotometer 2000 of the second embodiment, no additional member such as a mirror is required.

[0064] In addition, according to the spectrophotometer 2000 of the second embodiment, even if the light-emitting area of ​​the observation light source 2084 is small, the observation light is irradiated onto the entire entrance pupil of the spectroscope 2022, and therefore the NA of the observation light that has passed through the slit 2100 is equal to the NA of the spectroscope 2022. Therefore, even if the slit 2100 is not positioned at a position optically conjugate with the measurement position 2220, the entire measurement area can be observed.

[0065] 2.5 Wavelength of observation light The observation light may have a wavelength outside the wavelength range of the optical spectrum to be measured. For example, if the wavelength range of the optical spectrum to be measured is in the visible range, the observation light may have a wavelength in the ultraviolet or infrared range. This prevents the observation light from affecting the measurement of the optical spectrum, making it possible to observe the measurement position 2220 when measuring the optical spectrum.

[0066] When the observation light has a wavelength outside the wavelength range of the optical spectrum to be measured, the camera 2025 has sensitivity to the wavelength of the observation light and captures an image of the position to be measured 2220 .

[0067] 2.6 Diffraction grating arrangement Fig. 6 is a perspective view illustrating the arrangement of a diffraction grating in a spectrophotometer according to the second embodiment. Fig. 7 is a perspective view illustrating the arrangement of a diffraction grating that is compared with the arrangement of the diffraction grating in the spectrophotometer according to the second embodiment.

[0068] In the spectrophotometer 2000 of the second embodiment, as shown in FIG. 6, a diffraction grating 2082 is installed so that the −1st-order diffracted light 2320 deviates from a plane 2500 that includes the chief ray of the measured light 2300 traveling along the measurement optical path 2120 and the chief ray of the 0th-order light 2321.

[0069] 7 , when the −1st-order diffracted light 2320 does not deviate from a plane 2500 including the chief ray of the measured light 2300 traveling along the measurement optical path 2120 and the chief ray of the zeroth-order light 2321, the −1st-order diffracted light 2320 generated by the diffraction grating 2082 diffracting the measured light 2300 heads toward the same position as the first-order diffracted light 2322 generated by the diffraction grating 2082 diffracting light from the optical path of the zeroth-order light 2321, and the line sensor 2083 receives both the −1st-order diffracted light 2320 and the first-order diffracted light 2322. Therefore, reflected light generated by the observation light source 2084 reflecting the zeroth-order light 2321 or fluorescence emitted when the observation light source 2084 receives the zeroth-order light 2321 becomes stray light and affects the measurement of the spectral spectrum.

[0070] 6 , when the diffraction grating 2082 is rotated with respect to the −1st-order diffracted light 2320 and the zeroth-order light 2321 so that the −1st-order diffracted light 2320 deviates from a plane 2500 that includes the chief ray of the measured light 2300 traveling along the measurement optical path 2120 and the chief ray of the zeroth-order light 2321, the −1st-order diffracted light 2320 generated by the diffraction grating 2082 diffracting the measured light 2300 heads toward a position different from the position toward which the first-order diffracted light 2322 generated by the diffraction grating 2082 diffracting light from the optical path of the zeroth-order light 2321 heads, and the line sensor 2083 receives the −1st-order diffracted light 2320 but does not receive the first-order diffracted light 2322. Therefore, reflected light generated by the observation light source 2084 reflecting the zeroth-order light 2321 or fluorescence emitted when the observation light source 2084 receives the zeroth-order light 2321 does not affect the measurement of the spectral spectrum.

[0071] Although the present invention has been described in detail, the above description is illustrative in all respects and does not limit the present invention, and it is understood that countless variations not illustrated can be envisaged without departing from the scope of the present invention. [Explanation of symbols]

[0072] 1000,2000 spectrophotometer 1020,2020 Illumination optical system 1021,2021 Light receiving optical system 1022,2022 Spectrometer 1023,2023 Controller 1024,2024 Operation section 1060,2060 receiving lens 1080,2080 slit plate 1081,2081 Lens 1082,2082 diffraction grating 1083,2083 line sensor 1084,1380,2084 Observation light source 1085 Insertion / extraction mechanism 1100,2100 slit 1120,2120 Measurement optical path 1220,2220 Measured position 1240,2240 Light to be measured 1320,2320 -1st order diffracted light 1400, 1401, 1402 LEDs 2025 Camera 2321 0th order light

Claims

1. an illumination optical system including an illumination light source and an integrating sphere having a measurement aperture, and illuminating a sample placed opposite the measurement aperture with diffused light; a light-receiving optical system that forms an image of the light to be measured from the position to be measured on the sample, which is incident through the measurement opening, and generates the imaged light to be measured; a spectroscope that separates the light to be measured that has been imaged by the light receiving optical system; a sensor that receives the dispersed light to be measured and outputs a signal representing an optical characteristic; an observation light source that emits observation light for illuminating the measurement position of the sample facing the measurement opening through the measurement opening when observing the measurement position; an auxiliary light source that emits illumination light for illuminating a surface of the sample facing the measurement opening through the measurement opening when observing the position to be measured through the measurement opening, simultaneously with the emission of observation light by the observation light source; a camera that captures an image of a surface of a sample facing the measurement opening through the measurement opening; Equipped with the observation light is imaged on the sample by the light receiving optical system, illuminating a position to be measured on the sample; the measurement position illuminated by the observation light is a part of the surface of the sample illuminated by the illumination light, The camera captures an image of the surface of the sample facing the measurement opening, including the illuminated measurement position, through an optical path different from the optical path of the light-receiving optical system.

2. 2. The spectrophotometer according to claim 1, wherein the measurement of the optical characteristics of the measurement position and the observation of the measurement position are performed at different times.

3. 3. The spectrophotometer according to claim 1, wherein the auxiliary light source and the illumination light source are configured such that a common light source functions as both the auxiliary light source and the illumination light source by using the illumination light source as the auxiliary light source when observing the measurement position.

4. The observation light source is a light-emitting diode that emits the observation light; Equipped with 4. The spectrophotometer according to claim 1.

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