Spectrometer and optical apparatus

Abstract

To provide a spectrometer whose accuracy is improved compared with conventional techniques, and an optical apparatus including the spectrometer.SOLUTION: A spectrometer includes: a spectroscopic element 40 that spectrally disperses incident light (reflected light L2) in accordance with wavelength; a detector (line sensor 42) that has a plurality of pixels 42a, and receives spectrally dispersed light L2a for respective wavelengths dispersed by the spectroscopic element 40 with mutually-different pixels 42a; and low-emissivity members 44, 46 that are provided on at least one of a first direction side and a second direction side of the spectroscopic element 40 and the detector when one direction side of a spectroscopic direction A of the spectroscopic element 40 is defined as the first direction side and the other direction side of the spectroscopic direction A is defined as the second direction side.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a spectrometer and an optical device including the spectrometer. [Background technology]

[0002] A displacement meter employing the color confocal method is known as a measuring device for measuring the shape (displacement) of the surface of a measurement object. This displacement meter includes a color confocal optical system and a spectrometer. The color confocal optical system emits measurement light toward the surface of the measurement object. The measurement light reflected by the surface of the measurement object is incident on the color confocal optical system. The color confocal optical system then emits, to the spectrometer, the reflected measurement light in a wavelength range that is focused on the surface of the measurement object, among the light reflected by the surface of the measurement object.

[0003] The spectroscope includes a spectroscopic element and a line sensor (see Patent Document 1). The spectroscopic element separates reflected light (incident light) incident from the color confocal optical system. The line sensor has a plurality of pixels arranged in a line, and receives the light separated by the spectroscopic element for each wavelength at different pixels. The shape of the surface of the object to be measured can be calculated based on the light reception signals output from the line sensor that indicate the intensity of reflected light for each wavelength. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-67611 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a light source such as an LED (Light Emitting Diode) is placed near the spectrometer, parts of the spectrometer can be heated by light leaking from the light source and by radiated light from areas heated by the light source. As a result, a temperature gradient can occur in the spectrometer. In this case, the spectrometer's wavelength calibration (the relationship between each pixel of the line sensor and the wavelength of the light it receives) changes, degrading the spectrometer's accuracy.

[0006] To prevent this deterioration in spectrometer accuracy, one possible approach is to wait for the spectrometer to heat up due to the light emitted from the LED light source, and then calibrate the spectrometer (obtaining the correlation between each pixel of the line sensor and the wavelength of the received light) once the spectrometer and light source have reached thermal equilibrium. However, this approach has the drawback of not being able to start measurements using the displacement meter until the spectrometer and other components have reached thermal equilibrium. Furthermore, if the light intensity of the LED light source is changed, the spectrometer will reach a different thermal equilibrium state from the state before the change in LED light intensity, thereby degrading the spectrometer's accuracy.

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide a spectroscope with improved accuracy compared to conventional spectroscopes, and an optical device equipped with such a spectroscope. [Means for solving the problem]

[0008] The spectrometer for achieving the object of the present invention comprises: a spectroscopic element for separating incident light according to wavelength; The device includes a detector having a plurality of pixels and receiving light separated by the spectroscopic element for each wavelength at different pixels, and a low-emissivity member provided on at least one of the first direction side and the second direction side of the spectroscopic element and the detector, when one side of the spectroscopic direction of the spectroscopic element is defined as the first direction side and the other side of the spectroscopic direction is defined as the second direction side.

[0009] This spectrometer can reduce the temperature gradient in the spectroscopic direction of the spectrometer.

[0010] In a spectrometer according to another aspect of the present invention, when a direction parallel to a plane including the wavelength-separated light beams split by the spectroscopic element and perpendicular to the spectroscopic direction is defined as a first perpendicular direction, and one side of the first perpendicular direction is defined as a third direction, the detector is provided on the third direction side of the spectroscopic element, thereby making it possible to reduce the temperature gradient in the spectroscopic direction of the spectrometer.

[0011] In a spectrometer according to another aspect of the present invention, low-emissivity members are provided on the first and second direction sides of the spectroscopic element and the detector, thereby making it possible to reduce the temperature gradient in the spectroscopic direction of the spectrometer.

[0012] In a spectrometer according to another aspect of the present invention, when a high-temperature section having a temperature higher than that of the spectrometer is provided on the first or second direction side of the spectroscopic element and the detector, a low-emissivity member is provided between the spectroscopic element and the detector and the high-temperature section, thereby making it possible to reduce the temperature gradient in the spectroscopic direction of the spectrometer.

[0013] In a spectrometer according to another aspect of the present invention, when the other side of the first perpendicular direction is defined as a fourth direction side, high-emissivity members are provided on the fourth direction side of the spectroscopic element and on the third direction side of the detector. This reduces the temperature gradient in the spectroscopic direction of the spectrometer and enables the spectrometer to reach thermal equilibrium with the ambient environment in a shorter time, thereby achieving both improved accuracy and improved cost efficiency of the spectrometer.

[0014] In a spectrometer according to another aspect of the present invention, when the other side of the first vertical direction is defined as a fourth direction side, the direction perpendicular to the spectroscopic direction and the first vertical direction is defined as a second vertical direction, one side of the second vertical direction is defined as a fifth direction side, and the other side of the first vertical direction is defined as a sixth direction side, low-emissivity members are further provided on the fourth direction side of the spectroscopic element and the third direction side of the detector, and high-emissivity members are provided on the fifth and sixth direction sides of the spectroscopic element and the detector. This makes it possible to achieve both improved accuracy and improved economy of the spectrometer.

[0015] In a spectrometer according to another aspect of the present invention, the detector is a line sensor having a plurality of pixels arranged in a spectral direction.

[0016] An optical device for achieving the object of the present invention comprises the above-mentioned spectrometer, a high-temperature section that is located on the first direction side or the second direction side of the spectrometer and has a higher temperature than the spectrometer, and a partition wall that is located between the spectrometer and the high-temperature section.

[0017] With this optical device, radiant heat from the high-temperature area is transmitted to the spectrometer by going around the partition wall, thereby preventing an increase in the heat flow to only a specific surface of the spectrometer.As a result, the temperature uniformity of the spectrometer is improved, thereby further improving the accuracy of the spectrometer.

[0018] In the optical device according to another aspect of the present invention, an opening is formed in the partition wall, which allows the temperature distribution of the spectroscope to be made uniform in a shorter time.

[0019] In the optical device according to another aspect of the present invention, the high temperature part is a light source part. [Effects of the Invention]

[0020] The present invention can improve the accuracy of the spectrometer. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram of a displacement meter according to a first embodiment. [Figure 2] FIG. 2 is an enlarged view of the controller of the first embodiment. [Figure 3] FIG. 3 is an enlarged view of a portion of the line sensor shown in FIG. [Figure 4] 10 is a graph showing an example of the intensity of reflected light for each wavelength of reflected light detected by a line sensor. [Figure 5] FIG. 10 is a diagram illustrating an example of a spectroscope of a comparative example that does not include a low-emissivity member. [Figure 6] 10A and 10B are explanatory diagrams for explaining a problem of the spectrometer of the comparative example. [Figure 7] FIG. 2 is an explanatory diagram for explaining a low-emissivity member of the spectroscope. [Figure 8] 8 shows an enlarged view of the low-emissivity member within the dotted circle C1 in FIG. 7 and an enlarged view of the low-emissivity member within the dotted circle C2 in FIG. 7. [Figure 9] 8 is a diagram showing a modified example of the low-emissivity member within the dotted circle C1 in FIG. 7 and a modified example of the low-emissivity member within the dotted circle C2 in FIG. 7. FIG. [Figure 10] FIG. 10 is a diagram illustrating a case where a temperature gradient occurs in the Y direction of the spectrometer. [Figure 11] FIG. 10 is a diagram illustrating a case where a temperature gradient occurs in the X direction of the spectrometer. [Figure 12] FIG. 10 is a schematic diagram of a spectroscope of a displacement meter according to a second embodiment. [Figure 13] FIG. 10 is a schematic diagram of a spectroscope of a displacement meter according to a third embodiment. [Figure 14] FIG. 11 is a view of the spectroscope of the displacement meter of the fourth embodiment as viewed from the X direction side. [Figure 15] FIG. 11 is a view of the spectroscope of the displacement meter of the fourth embodiment as viewed from the +Z direction side. [Figure 16] FIG. 10 is a schematic diagram of a controller of a displacement meter according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] [First embodiment] Fig. 1 is a schematic diagram of a displacement meter 10 according to a first embodiment. As shown in Fig. 1, the displacement meter 10 corresponds to the optical device of the present invention, and measures the shape (displacement, distance to the surface) of the surface of a workpiece W, which is an object to be measured. Note that the X, Y, and Z directions in the figure are perpendicular to one another.

[0023] The displacement meter 10 includes a color confocal optical system 11, a controller 12, optical fiber cables 13, 14, and 15, and an optical fiber coupler 16. One end of the optical fiber cable 13 is connected to the color confocal optical system 11, and the optical fiber coupler 16 is connected to the other end of the optical fiber cable 13. The optical fiber coupler 16 connects the other end of the optical fiber cable 13 to one ends of the optical fiber cables 14 and 15. The other ends of the optical fiber cables 14 and 15 are each connected to the controller 12.

[0024] The controller 12 emits measurement light L1, which is white light, to the color confocal optical system 11 via the optical fiber cable 14, the optical fiber coupler 16, and the optical fiber cable 13. The controller 12 also disperses and receives reflected light L2 of the measurement light L1 that is incident from the color confocal optical system 11 via the optical fiber cable 13, the optical fiber coupler 16, and the optical fiber cable 15, and calculates the surface shape of the workpiece W.

[0025] The color confocal optical system 11 includes a cylindrical lens barrel 20 with a bottom, an objective lens 21, and an eyepiece lens 22.

[0026] An objective lens 21 is provided at the opening at the tip end of the lens barrel 20, and an eyepiece lens 22 is provided inside the lens barrel 20. One end of the optical fiber cable 13 is connected to the bottom of the lens barrel 20, and the end face of this end, that is, the fiber end face 13a, faces the eyepiece lens 22 inside the lens barrel 20. As a result, the measurement light L1 that has entered from the controller 12 via the optical fiber cable 14, the optical fiber coupler 16, and the optical fiber cable 13 is emitted from the fiber end face 13a toward the eyepiece lens 22, passes through the eyepiece lens 22, and enters the objective lens 21.

[0027] The objective lens 21 focuses the measurement light L1 incident through the eyepiece lens 22 onto the surface of the workpiece W. At this time, the focal position differs for each wavelength of the measurement light L1 due to chromatic aberration of the objective lens 21. Reflected light L2 of each wavelength of the measurement light L1 reflected by the surface of the workpiece W is incident on the objective lens 21, and this reflected light L2 is emitted toward the eyepiece lens 22.

[0028] The eyepiece 22 forms an image on the fiber end face 13a of only the reflected light L2 of the measurement light L1 in the wavelength range that has been imaged on the surface of the workpiece W. As a result, the fiber end face 13a functions as an aperture, and only the reflected light L2 of the measurement light L1 in the wavelength range that has been imaged on the surface of the workpiece W is emitted to the controller 12 via the optical fiber cable 13, the optical fiber coupler 16, and the optical fiber cable 15.

[0029] Fig. 2 is an enlarged view of the controller 12 of the first embodiment. As shown in Fig. 2 and the above-described Fig. 1, the controller 12 includes a power supply 30, a light source unit 32, a spectroscope 34, a control circuit 36, and a case 12a that houses these components. The case 12a also includes an output connector 38 to which the other end of the optical fiber cable 14 is connected, and an input connector 39 to which the other end of the optical fiber cable 15 is connected.

[0030] The power supply 30 supplies driving power to the light source unit 32 and the control circuit 36 ​​.

[0031] The light source unit 32 includes an LED light source 32a and an optical fiber cable 33. The LED light source 32a emits measurement light L1. Note that a light source other than an LED may be used. One end of the optical fiber cable 33 is disposed opposite the LED light source 32a, and the other end is connected to an output connector 38. As a result, the measurement light L1 emitted from the LED light source 32a enters the color confocal optical system 11 via the optical fiber cable 33, the output connector 38, the optical fiber cable 14, the optical fiber coupler 16, and the optical fiber cable 13.

[0032] An incident connector 39 is connected to the spectroscope 34, and the reflected light L2 enters from this incident connector 39. The spectroscope 34 separates the reflected light L2 (corresponding to incident light of the present invention) entering from the incident connector 39 and detects the intensity of the split light L2a for each wavelength. The spectroscope 34 includes a spectroscopic element 40, a line sensor 42, and low-emissivity members 44 and 46.

[0033] A diffraction grating, for example, is used as the spectroscopic element 40. This spectroscopic element 40 disperses the reflected light L2 incident in the -Z direction from the input connector 39, and emits the separated light L2a for each wavelength toward the line sensor 42 located on the +Y direction side of the spectroscopic element 40. Here, the arrow in FIG. 2 indicates the spectroscopic direction A of the spectroscopic element 40.

[0034] The spectral direction A of the spectral element 40 is a direction that intersects with the traveling direction of the spectral light L2a of each wavelength separated by the spectral element 40 (here, the direction from the spectral element 40 toward the line sensor 42: the +Y direction) in a plane (here, the YZ plane) that includes the spectral light L2a of each wavelength, and in this embodiment, is the Z direction. If the spectral direction A is defined as the Z direction, the Y direction, which is parallel to the YZ plane that includes the spectral light L2a of each wavelength and perpendicular to the Z direction, corresponds to the first vertical direction of the present invention. Furthermore, the X direction corresponds to the second vertical direction of the present invention.

[0035] In this embodiment, a diffraction grating is used as the spectroscopic element 40, but a prism, an optical filter, or the like may be used instead. In this case, the position of the input connector 39 is changed appropriately depending on the type of spectroscopic element 40.

[0036] The line sensor 42 corresponds to a detector of the present invention, and as described above, is arranged on the +Y direction side (corresponding to the third direction side of the present invention) of the spectroscopic element 40. The line sensor 42 includes a plurality of pixels 42a (also referred to as light receiving elements) arranged in a row along the spectroscopic direction A (Z direction). The line sensor 42 receives the light beams L2a of each wavelength separated by the spectroscopic element 40 at different pixels 42a, and outputs light receiving signals indicating the spectral intensities (reflected light intensities) of the respective pixels 42a to the control circuit 36.

[0037] Fig. 3 is an enlarged view of a portion of the line sensor 42 shown in Fig. 2. Fig. 4 is a graph showing an example of the reflected light intensity for each wavelength of the reflected light L2 (spectral light L2a in each wavelength range) detected by the line sensor 42. Note that in Fig. 3, pixel numbers (1, 2, 3, ...) are assigned to each pixel 42a of the line sensor 42 from the +Z direction side to the -Z direction side.

[0038] As shown in Fig. 3, wavelength calibration is performed in advance on the spectrometer 34 using a light source that emits light of a known wavelength. Wavelength calibration involves obtaining the relationship between each pixel 42a (pixel number) of the line sensor 42 and the wavelengths (λ1, λ2, λ3, λ4, ...) of the light beams L2a incident on each pixel 42a. Based on the wavelength calibration result and the light reception signal (signal intensity) for each pixel 42a of the line sensor 42, the reflected light intensity for each wavelength of the reflected light L2 as shown in Fig. 4 is obtained.

[0039] 1 and 2, the low-emissivity members 44, 46 will be described later. The control circuit 36 ​​controls the operation of the LED light source 32a and the line sensor 42. The control circuit 36 ​​also calculates the reflected light intensity for each wavelength of the reflected light L2 as shown in FIG. 4 based on the light-receiving signals output from each pixel 42a of the line sensor 42 and the wavelength calibration results described above, and calculates the distance to the surface of the workpiece W using a known method based on these calculation results. This makes it possible to measure the surface shape of the workpiece W.

[0040] Next, the low-emissivity members 44, 46 will be described. The light source unit 32 is disposed on the -Z direction side of the spectroscope 34 (corresponding to the first or second direction side of the present invention). Therefore, the -Z direction side of the spectroscope 34 is heated by leaked light from the light source unit 32 and radiated light from an area heated by the light source unit 32. For this reason, it can be said that a high-temperature section HS (see FIG. 5) that is hotter than the spectroscope 34 is disposed on the -Z direction side of the spectroscope 34. Note that this high-temperature section HS may include the power supply 30 in addition to the light source unit 32. On the other hand, since nothing is disposed on the +Z direction side of the spectroscope 34 (corresponding to the second or first direction side of the present invention), it can be said that a low-temperature section LS (see FIG. 5) that is cooler than the spectroscope 34 is disposed on the +Z direction side of the spectroscope 34.

[0041] Fig. 5 is a diagram showing an example of a spectroscope 34A of a comparative example that does not include the low-emissivity members 44, 46. Fig. 6 is an explanatory diagram for explaining the problems with the spectroscope 34A of the comparative example. The spectroscope 34A of the comparative example has basically the same configuration as the spectroscope 34, except that it does not include the low-emissivity members 44, 46.

[0042] 5, in the spectroscope 34A of the comparative example that does not include the low-emissivity members 44, 46, the emissivity is higher (the reflectivity is lower) at the end on the -Z direction side and the end on the +Z direction side compared to the spectroscope 34 that includes the low-emissivity members 44, 46 described below. For this reason, the radiant heat T2 reflected at the end on the -Z direction side of the spectroscope 34A is smaller than the radiant heat T1 transmitted from the high-temperature part HS to the end on the -Z direction side of the spectroscope 34A, resulting in a larger temperature rise at the end on the -Z direction side of the spectroscope 34A.

[0043] Furthermore, radiant heat T3 transferred from the end of spectroscope 34A on the +Z direction side to low-temperature section LS is greater than radiant heat T4 transferred from low-temperature section LS to the end of spectroscope 34A on the +Z direction side, resulting in a greater temperature drop at the end of spectroscope 34A on the +Z direction side. As a result, the temperature gradient in the Z direction of spectroscope 34A (spectrographic direction A, the long-axis direction of line sensor 42) becomes greater.

[0044] When the temperature gradient in the Z direction of the spectrometer 34A increases, as indicated by reference symbol 6A in Fig. 6, the grating surface of the spectroscopic element 40 (diffraction grating) may be displaced or deformed, as indicated by reference symbol 6B in Fig. 6, and, although not shown, non-uniform deformation of the line sensor 42 may also occur. In this case, the wavelength calibration of the spectrometer 34A is lost, and the accuracy of the spectrometer 34A deteriorates. Therefore, in the spectrometer 34 of this embodiment, low-emissivity members 44, 46 are provided to suppress the temperature gradient in the Z direction of the spectrometer 34.

[0045] Fig. 7 is an explanatory diagram illustrating the low emissivity members 44, 46 of the spectroscope 34. Fig. 8 shows an enlarged view (see reference numeral 8A) of the low emissivity member 44 within the dotted circle C1 in Fig. 7, and an enlarged view (see reference numeral 8B) of the low emissivity member 46 within the dotted circle C2 in Fig. 7.

[0046] 7 and 8, the low-emissivity members 44, 46 are formed, for example, in the shape of flat plates parallel to the XY plane and have low emissivity (high reflectivity and low absorptivity). The emissivity of the low-emissivity members 44, 46 is 0.15 or less, and more preferably 0.05 or less. The low-emissivity member 44 is provided on the −Z direction side (one side in the spectral direction A) of the spectroscopic element 40 and the line sensor 42, and functions as a sidewall portion on the −Z direction side of the spectrometer 34. The low-emissivity member 46 is provided on the +Z direction side (the other side in the spectral direction A) of the spectroscopic element 40 and the line sensor 42, and functions as a sidewall portion on the +Z direction side of the spectrometer 34.

[0047] The low-emissivity member 44 includes, for example, a flat plate-shaped main body 50 parallel to the XY plane and a low-emissivity layer 52 provided on the surface of the main body 50 in the -Z direction (see reference numeral 8A in FIG. 8). Specifically, the main body 50 (low-emissivity member 44) is made of aluminum, and the surface in the -Z direction is polished to form a polished aluminum surface which serves as the low-emissivity layer 52. In this case, the emissivity of the low-emissivity member 44 is approximately 0.05.

[0048] Furthermore, a low-emissivity sheet (e.g., a metal foil sheet or an aluminum vapor-deposited sheet) may be attached to the surface of the main body 50 on the -Z direction side as the low-emissivity layer 52. For example, when an aluminum vapor-deposited sheet is used as the low-emissivity layer 52, the emissivity of the low-emissivity member 44 is approximately 0.04. Furthermore, in this case, instead of a low-emissivity sheet, a multilayer film of a metal layer with low emissivity and an insulator may be attached to the surface of the main body 50 on the -Z direction side.

[0049] The low-emissivity member 46 has basically the same configuration as the low-emissivity member 44, except that a low-emissivity layer 52 is provided on the surface of the main body 50 on the +Z direction side (see reference numeral 8B in FIG. 8).

[0050] 9 shows a modified example of the low-emissivity member 44 (see reference numeral 9A) within the dotted circle C1 in FIG. 7 and a modified example of the low-emissivity member 46 (see reference numeral 9B) within the dotted circle C2 in FIG. 7. As shown by reference numeral 9A in FIG. 9, instead of providing a low-emissivity layer 52 only on the surface of the main body 50 of the low-emissivity member 44 on the −Z direction side, the low-emissivity layer 52 may be provided on both surfaces of the main body 50 in the Z direction. Furthermore, as shown by reference numeral 9B in FIG. 9, instead of providing a low-emissivity layer 52 only on the surface of the main body 50 of the low-emissivity member 46 on the +Z direction side, the low-emissivity layer 52 may be provided on both surfaces of the main body 50 in the Z direction.

[0051] 7, by providing the low-emissivity member 44 on the -Z direction side of the spectroscopic element 40 and the line sensor 42, the radiant heat T1 transmitted from the high-temperature part HS to the end of the spectrometer 34 on the -Z direction side is reflected by the low-emissivity member 44. As a result, the radiant heat T2 reflected at the end of the spectrometer 34 on the -Z direction side is larger than in the comparative example shown in FIG. 5 (hereinafter simply referred to as the comparative example). As a result, the temperature rise at the end of the spectrometer 34 on the -Z direction side is suppressed more than in the comparative example.

[0052] Furthermore, by providing the low-emissivity member 46 on the +Z direction side of the spectroscopic element 40 and the line sensor 42, the radiant heat T3 transmitted from the end of the spectrometer 34 on the +Z direction side to the low-temperature section LS is reduced by the low-emissivity member 46. As a result, the temperature drop at the end of the spectrometer 34 on the +Z direction side is suppressed more than in the comparative example.

[0053] By providing the low-emissivity member 44 on the -Z direction side of the spectroscopic element 40 and the line sensor 42 and the low-emissivity member 46 on the +Z direction side in this way, the temperature gradient in the Z direction (spectroscopic direction A, the long axis direction of the line sensor 42) of the spectrometer 34 can be made smaller than in the comparative example. As a result, displacement or deformation of the grating surface of the spectroscopic element 40 (diffraction grating) and non-uniform deformation of the line sensor 42 are suppressed. This suppresses the collapse of the wavelength calibration of the spectrometer 34, thereby making it possible to improve the accuracy of the spectrometer 34 compared to conventional methods.

[0054] Next, the reason why the spectrometer 34 of the first embodiment only suppresses the occurrence of a temperature gradient in the Z direction (spectroscopic direction A, the long axis direction of the line sensor 42) will be described.

[0055] Symbols XA and XB in Fig. 10 are diagrams illustrating a case where a temperature gradient occurs in the Y direction of the spectroscope 34. Symbols XIA and XIB in Fig. 11 are diagrams illustrating a case where a temperature gradient occurs in the X direction of the spectroscope 34. Note that symbol XIA in Fig. 11 is a diagram of the spectroscope 34 as viewed from the +Z direction side. In addition, to avoid complication of the drawings, low emissivity members 44, 46 are omitted from Figs. 10 and 11.

[0056] 10, even if a temperature gradient occurs in the Y direction of the spectrometer 34, the line sensor 42 will be uniformly deformed (not shown). Therefore, the error in the wavelength calibration of the spectrometer 34 will be smaller than when a temperature gradient occurs in the Z direction as in the comparative example.

[0057] 11, even if a temperature gradient occurs in the X direction of the spectrometer 34, the spectroscopic element 40 and the line sensor 42 will only deform in the X direction. Therefore, the error in the wavelength calibration of the spectrometer 34 will be smaller than when a temperature gradient occurs in the Z direction as in the comparative example.

[0058] Therefore, as in the spectroscope 34 of the first embodiment, the accuracy of the spectroscope 34 can be improved simply by reducing the temperature gradient in the Z direction using the low emissivity members 44, 46.

[0059] [Second embodiment] Fig. 12 is a schematic diagram of the spectroscope 34 of the displacement meter 10 of the second embodiment. In the spectroscope 34 of the first embodiment, the low emissivity member 44 is provided on the -Z direction side of the spectroscopic element 40 and the line sensor 42, and the low emissivity member 46 is provided on the +Z direction side, but as shown in Fig. 12, the low emissivity member 44 may be provided only on the -Z direction side of the spectroscopic element 40 and the line sensor 42.

[0060] The displacement meter 10 of the second embodiment has basically the same configuration as the first embodiment, except that it omits the low-emissivity member 46 of the spectroscope 34. Therefore, the same reference numerals are used to designate the same components in terms of function or configuration as those of the first embodiment, and the description thereof will be omitted.

[0061] As in the second embodiment, simply providing the low-emissivity member 44 only between the spectroscope 34 (spectroscope element 40 and line sensor 42) and the high-temperature part HS suppresses the temperature rise at the end of the spectroscope 34 on the -Z direction side due to the influence of the high-temperature part HS more than in the comparative example. This makes the temperature gradient in the Z direction of the spectroscope 34 smaller than in the comparative example. As a result, the accuracy of the spectroscope 34 can be improved.

[0062] [Third embodiment] Fig. 13 is a schematic diagram of the spectrometer 34 of the displacement meter 10 of the third embodiment. As shown in Fig. 13, the displacement meter 10 of the third embodiment has basically the same configuration as the displacement meter 10 of each of the above embodiments, except that high-emissivity members 60, 62 are provided in the spectrometer 34. For this reason, parts that are the same in function or configuration as those of the above embodiments are given the same reference numerals, and their description will be omitted.

[0063] The high-emissivity members 60, 62 are formed, for example, in the shape of flat plates parallel to the ZX plane, and have high emissivity (low reflectivity and high absorptivity). The emissivity of the high-emissivity members 60, 62 is 0.4 or higher, and more preferably 0.5 or higher. The high-emissivity member 60 is provided on the -Y direction side (corresponding to the fourth direction side of the present invention) of the spectroscopic element 40, and functions as a sidewall portion on the -Y direction side of the spectroscope 34. The high-emissivity member 62 is provided on the +Y direction side of the line sensor 42, and functions as a sidewall portion on the +Y direction side of the spectroscope 34.

[0064] The high-emissivity members 60, 62 are, for example, aluminum plates parallel to the ZX plane, with both sides (or one side) anodized, more preferably with matte black anodized. The emissivity of the high-emissivity members 60, 62 when anodized (with an anodized aluminum surface) is approximately 0.5, and the emissivity of the high-emissivity members when anodized (with a matte black anodized aluminum surface) is approximately 0.95.

[0065] Alternatively, aluminum plates parallel to the ZX plane with roughened surfaces on both sides (or one side) may be used as the high-emissivity members 60, 62. For example, when the high-emissivity members 60, 62 are subjected to a blasting process to increase the surface roughness, the emissivity is approximately 0.4.

[0066] By providing high-emissivity members 60, 62 on the -Y and +Y sides of spectrometer 34 in this manner, heat exchange is quickly carried out between the surrounding environment of spectrometer 34 (high-temperature section HS, low-temperature section LS, etc.) and the housing of spectrometer 34. This allows spectrometer 34 to reach thermal equilibrium with the surrounding environment in a shorter time. As a result, the time from when displacement meter 10 is started until spectrometer 34 becomes stable (reaches thermal equilibrium) can be shortened, thereby further improving economy.

[0067] Here, if high-emissivity members 60, 62 are provided in the spectroscope 34, there is a risk of a temperature gradient occurring in the Y direction of the spectroscope 34 as shown in Fig. 10, but as described above, this does not have a significant effect on the accuracy of the spectroscope 34. Therefore, the spectroscope 34 of the third embodiment can achieve both improved accuracy and improved economy.

[0068] [Fourth embodiment] Fig. 14 is a view of the spectroscope 34 of the displacement meter 10 of the fourth embodiment as viewed from the X direction side. Fig. 15 is a view of the spectroscope 34 of the displacement meter 10 of the fourth embodiment as viewed from the +Z direction side. As shown in Figs. 14 and 15, the displacement meter 10 of the fourth embodiment has basically the same configuration as the displacement meter 10 of the first embodiment, except that it is provided with low emissivity members 47, 48 and high emissivity members 64, 66. For this reason, parts that are the same in function or configuration as those of the first embodiment are given the same reference numerals, and their description will be omitted.

[0069] The low emissivity members 47 and 48 are formed, for example, in the shape of a flat plate parallel to the XZ plane, and are basically the same as the previously described low emissivity members 44 and 46. The emissivity of the low emissivity members 47 and 48 may be the same as or different from the emissivity of the low emissivity members 44 and 46.

[0070] The low-emissivity member 47 is provided on the −Y direction side of the spectroscopic element 40, and functions as a sidewall portion on the −Y direction side of the spectroscope 34. It is preferable that a low-emissivity layer 52 (see FIGS. 8 and 9) is formed on the surface on the −Y direction side of the low-emissivity member 47 or on both surfaces in the Y direction.

[0071] The low-emissivity member 48 is provided on the +Y direction side of the line sensor 42, and functions as a sidewall portion on the +Y direction side of the spectroscope 34. It is preferable that a low-emissivity layer 52 (see FIGS. 8 and 9) is formed on the surface of the low-emissivity member 48 on the +Y direction side or on both surfaces in the Y direction.

[0072] The high emissivity members 64, 66 are formed, for example, in the shape of flat plates parallel to the YZ plane, and are basically the same as the above-mentioned high emissivity members 60, 62. The emissivity of the high emissivity members 64, 66 may be the same as or different from the emissivity of the high emissivity members 60, 62.

[0073] High-emissivity member 64 is provided on the +X direction side (corresponding to the fifth direction side of the present invention) of spectroscopic element 40 and line sensor 42, and functions as a sidewall portion on the +X direction side of spectroscope 34. High-emissivity member 66 is provided on the −X direction side (corresponding to the sixth direction side of the present invention) of spectroscopic element 40 and line sensor 42, and functions as a sidewall portion on the −X direction side of spectroscope 34.

[0074] In this way, in the spectrometer 34 of the fourth embodiment, the emissivity is reduced in the Z direction and the Y direction, and the emissivity is increased in the X direction. As a result, the spectrometer 34 of the fourth embodiment increases the emissivity in the X direction, which does not significantly affect the accuracy of the spectrometer 34, and thereby reaches a state of thermal equilibrium with the surrounding environment in a shorter time after activation of the displacement meter 10, as in the third embodiment. Furthermore, the spectrometer 34 of the fourth embodiment can improve the accuracy of the spectrometer 34, as in the above-mentioned embodiments, by reducing the temperature gradient in the Y direction and the Z direction (particularly the Z direction). As a result, the spectrometer 34 of the fourth embodiment can achieve both improved accuracy and improved economy.

[0075] Note that instead of reducing the emissivity in the Z and Y directions and increasing the emissivity in the X direction as in the spectrometer 34 of the fourth embodiment, it is also possible to reduce the emissivity in the Z and X directions and increase the emissivity in the Y direction.

[0076] [Fifth embodiment] Fig. 16 is a schematic diagram of the controller 12 of the displacement meter 10 of the fifth embodiment. As shown in Fig. 16, the displacement meter 10 of the fifth embodiment has basically the same configuration as the displacement meter 10 of each of the above embodiments, except that a partition wall 70 (also called a partition or a wall portion) is provided inside the controller 12.

[0077] The partition wall 70 is provided between the spectrometer 34 and the power supply 30 and light source unit 32 (high-temperature unit HS), and is formed in the shape of a screen (a flat plate parallel to the XY plane) that separates the two. This prevents radiant heat T1 from the high-temperature unit HS, such as the light source unit 32, from being directly transmitted to the end of the spectrometer 34 on the -Z direction side. In other words, the radiant heat T1 from the high-temperature unit HS is transmitted to the spectrometer 34 while going around the partition wall 70, thereby preventing an increase in the heat flow rate to only a specific surface of the spectrometer 34 (here, the surface on the -Z direction side). As a result, the temperature uniformity of the spectrometer 34 is improved, and the accuracy of the spectrometer 34 can be further improved.

[0078] In this case, it is desirable that the partition wall 70 has one or more openings 70a rather than completely separating the space between the spectrometer 34 and the power supply 30 and light source unit 32. By allowing air to pass through these openings 70a, the spectrometer 34 and the high-temperature parts HS such as the light source unit 32 can quickly reach a state of thermal equilibrium. As a result, the temperature distribution of the spectrometer 34 can be made uniform in a shorter time.

[0079] [others] In each of the above embodiments, the light source unit 32 and the power supply 30 (either one is acceptable) are used as examples of the high-temperature unit HS, but the high-temperature unit HS may also include various devices, components, and mechanisms that become hotter than the spectrometer 34, such as a control circuit 36 ​​(CPU, etc.).

[0080] In the above embodiments, the line sensor 42 has been described as an example of the detector of the present invention, but an area sensor in which the pixels 42a are arranged two-dimensionally may also be used as the detector of the present invention.

[0081] In each of the above embodiments, the low emissivity member 44 is provided on the −Z direction side of the spectroscope 34 and the line sensor 42, but the low emissivity member 44 may be provided only on the −Z direction side of either the spectroscope 34 or the line sensor 42. Also, the low emissivity member 46 may be provided only on the +Z direction side of either the spectroscope 34 or the line sensor 42.

[0082] In each of the above embodiments, the configurations shown in Figures 8 and 9 are exemplified as low-emissivity members 44, 46 to 48, but the type of suppression member is not particularly limited as long as it is capable of suppressing (reducing) temperature changes in the spectrometer 34 due to the influence of the surrounding environment (high-temperature section HS, low-temperature section LS, etc.) [including heat insulating material, heat-reflecting material (heat-reflecting plate, heat-reflecting glass)].

[0083] In the above embodiments, the displacement meter 10 has been described as an example of an optical device equipped with the spectrometer 34 of the present invention, but the present invention can be applied to various optical devices equipped with the spectrometer 34, such as a thickness measurement device equipped with the spectrometer 34. [Explanation of symbols]

[0084] 10...Displacement meter, 11...Color confocal optical system, 12...Controller, 12a...Case, 13...Optical fiber cable, 13a...Fiber end face, 14, 15...Optical fiber cable, 16...Optical fiber coupler, 20...Optical tube, 21...Objective lens, 22...Eyepiece, 30...Power supply, 32...Light source unit, 32a...LED light source, 33...Optical fiber cable, 34...Spectrometer, 34A...Spectrometer, 36 ...control circuit, 38...output connector, 39...input connector, 40...spectroscopic element, 42...line sensor, 42a...pixel, 44, 46 to 48...low emissivity member, 50...main body, 52...low emissivity layer, 60, 62, 64, 66...high emissivity member, 70...partition wall, 70a...opening, A...spectroscopic direction, HS...high temperature section, L1...measurement light, L2...reflected light, L2a...spectroscopic, LS...low temperature section, T1 to T4...radiant heat, W...work

Claims

1. a spectroscopic element that separates incident light according to wavelength; a detector having a plurality of pixels, the detector receiving light beams separated by the spectroscopic element for each wavelength at different pixels; a low-emissivity member provided on at least one of the first direction side and the second direction side of the spectroscopic element and the detector, where one direction side of the spectroscopic direction of the spectroscopic element is defined as a first direction side and the other direction side of the spectroscopic direction is defined as a second direction side; A spectrometer comprising:

2. 2. The spectrometer according to claim 1, wherein a direction parallel to a plane including the split light for each wavelength split by the spectroscopic element and perpendicular to the spectroscopic direction is defined as a first perpendicular direction, and one side of the first perpendicular direction is defined as a third direction side, and the detector is provided on the third direction side of the spectroscopic element.

3. The spectroscope according to claim 2 , wherein the low-emissivity members are provided on the first direction side and the second direction side of the spectroscopic element and the detector.

4. 3. The spectrometer according to claim 2, wherein a high-temperature section having a temperature higher than that of the spectrometer is provided on the first direction side or the second direction side of the spectroscopic element and the detector, and the low-emissivity member is provided between the spectroscopic element and the detector and the high-temperature section.

5. 4. The spectrometer according to claim 3, further comprising: a high-emissivity member provided on a fourth direction side of the spectroscopic element and a third direction side of the detector, where the other direction side of the first perpendicular direction is a fourth direction side.

6. when the other side of the first vertical direction is defined as a fourth direction side, a direction perpendicular to the spectroscopic direction and the first vertical direction is defined as a second vertical direction, one side of the second vertical direction is defined as a fifth direction side, and the other side of the first vertical direction is defined as a sixth direction side, the low emissivity member is further provided on the fourth direction side of the spectroscopic element and the third direction side of the detector, The spectroscope according to claim 3 , further comprising high-emissivity members provided on the fifth direction side and the sixth direction side of the spectroscopic element and the detector.

7. 7. The spectrometer according to claim 1, wherein the detector is a line sensor having a plurality of the pixels arranged in the direction of the spectrum.

8. A spectrometer according to any one of claims 1 to 6; a high-temperature section that is provided on the first direction side or the second direction side of the spectrometer and has a higher temperature than the spectrometer; a partition wall provided between the spectrometer and the high-temperature section; An optical device comprising:

9. 9. The optical device according to claim 8, wherein an opening is formed in the partition wall.

10. 9. The optical device according to claim 8, wherein the high-temperature portion is a light source portion.

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