Spectroscopic device, Raman spectroscopic measurement device, and spectroscopic method

Abstract

This spectroscopic device (5) receives light (L1) wavelength-decomposed in a predetermined direction by a spectroscopic optical system (4) including a spectroscopic element and outputs spectroscopic spectral data of the light (L1), and is provided with: a CMOS image sensor having a plurality of pixels (21) that receive the wavelength-decomposed light (L1) and convert the wavelength-decomposed light (L1) into electrical signals; the plurality of pixels (21) are arranged in a row direction along a wavelength decomposition direction and a column direction perpendicular to the row direction. A specifying unit (14) that specifies, as a specified pixel (21K), a pixel (21) from among the plurality of pixels (21) that forms a spectral spectral image (31) of the light (L1); and a generation unit (15) that integrates the pixel values of the specific pixels (21K) belonging to the same column, and generates spectral data based on the result of the integration.

Description

Technical Field

[0001] The present disclosure relates to a spectroscopic device, a Raman spectrometric measurement device and a spectroscopic method. Background Art

[0002] As an existing spectroscopic device, there is a spectroscopic device described in Patent Document 1, for example. This existing spectroscopic device is a so-called Raman spectroscopic device. The spectroscopic device includes: a mechanism for linearly irradiating excitation light; a movable stage on which a sample is placed; an objective lens that focuses Raman light from an area irradiated with excitation light; a narrow slot that is provided at an imaging position of the Raman light; a spectrometer that disperses light passing through the narrow slot; a CCD detector that detects a Raman spectrum image; and a control device that controls positioning measurement by synchronizing the movable stage with the CCD detector. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Publication No. 2016-180732 Summary of the invention The problem the invention is intended to solve

[0004] In the field of spectrometry such as Raman spectroscopy, fluorescence spectroscopy, and plasma spectroscopy, vertical binning of CCD image sensors is used when obtaining spectroscopic spectrum data in order to improve the signal-to-noise ratio. Vertical binning in CCD image sensors divides the charges generated in each pixel into multiple poles and adds them together. In CCD image sensors, read noise is only generated in the final amplifier and does not increase during the vertical binning process. Therefore, the more the number of vertical binning stages increases, the higher the signal-to-noise ratio can be.

[0005] As image sensors, CMOS image sensors are also known in addition to CCDs. However, at present, the popularity of CMOS image sensors has not progressed in the field of spectrometry. In CMOS image sensors, an amplifier is configured in each pixel to convert charge into voltage for each pixel. In the case of vertical binning in existing CMOS image sensors, the more the number of vertical binning stages increases, the more the readout noise is accumulated, so there is a problem that the signal S / N ratio is lower than when using a CCD image sensor.

[0006] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a spectroscopic device, a Raman spectrometry device, and a spectroscopic method that can acquire spectroscopic spectrum data with an excellent SN ratio. Technical means of solving problems

[0007] The gist of a spectrometer, a Raman spectrometry device, and a spectrometry method according to one embodiment of the present disclosure is as follows [1] to

[14] .

[0008] [1] A spectroscopic device that receives light decomposed by wavelength in a specified direction through a spectroscopic optical system including a spectroscopic element and obtains spectroscopic spectrum data of the light, and comprises: a CMOS image sensor having a pixel unit, the pixel unit having a plurality of pixels that receive the light decomposed by wavelength and convert them into electrical signals, and the plurality of pixels are arranged in a row direction along the wavelength decomposition direction and in a column direction perpendicular to the row direction; a specific unit that specifies a pixel that images the spectroscopic spectrum of the light among the plurality of pixels as a specific pixel; and a generating unit that integrates the pixel values ​​of the specific pixels belonging to the same column and generates spectroscopic spectrum data based on the integration result.

[0009] In the spectroscopic device, the pixel of the spectroscopic spectrum image that images the light decomposed by wavelength is specified as a specific pixel, and the pixel values ​​of the specific pixels belonging to the same column are integrated to generate spectroscopic spectrum data. By excluding other pixels that do not image the spectroscopic spectrum image from the integration of pixel values, the influence of read noise when integrating pixel values ​​can be fully reduced. Therefore, in the spectroscopic device, spectroscopic spectrum data can be obtained with an excellent SN ratio.

[0010] [2] The spectroscopic device of [1], wherein the specific unit excludes pixels whose readout noise exceeds a threshold value from the specific pixels. This can further reduce the influence of the readout noise when integrating pixel values. Therefore, the SN ratio of the spectroscopic spectrum data can be further improved.

[0011] [3] The spectroscopic device of [1] or [2], wherein the threshold of the readout noise is set to 0.1 [e - rms] and above 1.0[e - By setting such a threshold value, the influence of the read noise when integrating the pixel values ​​can be further reduced. Therefore, the SN ratio of the spectral spectrum data can be further improved.

[0012] [4] A spectroscopic device as in any one of [1] to [3], wherein the specific unit specifies pixels whose imaging area of ​​the spectroscopic spectrum image is 50% or more of the area of ​​the light receiving surface as the specific pixels. In this case, by excluding pixels that contribute less to the acquisition of the spectroscopic spectrum image from the specific pixels, the influence of read noise when integrating pixel values ​​can be further reduced. Therefore, the SN ratio of the spectroscopic spectrum data can be further improved.

[0013] [5] A spectroscopic device as described in any one of [1] to [3], wherein the specifying unit specifies the integration ratio of the specific pixel based on the aberration information of the light, and the generating unit integrates the pixel value of the specific pixel using the integration ratio. According to this structure, even if distortion due to aberration occurs in the spectral image of the light decomposed by wavelength, spectroscopic spectrum data with a good SN ratio can be obtained.

[0014] [6] A spectroscopic device as described in any one of [1] to [5], wherein the pixel unit comprises: a first pixel region and a second pixel region divided along the column direction, a first readout unit for reading out each pixel belonging to the first pixel region, and a second readout unit for reading out each pixel belonging to the second pixel region. In this case, the first pixel region and the second image region can be used respectively in accordance with the method of spectroscopic spectrum imaging. Therefore, spectroscopic spectrum data of various lights can be obtained with a good SN ratio.

[0015] [7] A spectroscopic device as in [6], wherein the first exposure time of each pixel belonging to the first pixel region is shorter than the second exposure time of each pixel belonging to the second pixel region. According to this configuration, for example, a spectroscopic spectrum image of light having different intensities according to wavelength can be obtained in the first pixel region and the second pixel region at different exposure times. By combining the saturated wavelength range of the spectroscopic spectrum data obtained in the first pixel region at a shorter exposure time with the non-saturated wavelength range of the spectroscopic spectrum data obtained in the second pixel region at a longer exposure time, spectroscopic spectrum data with a good SN ratio can be obtained in a high dynamic range.

[0016] [8] A spectroscopic device as in [7], wherein during the period in which image data of one frame is acquired in the second pixel region, image data of multiple frames is acquired in the first pixel region. In this case, even when different exposure times are set in the first pixel region and the second pixel region, the readout noise of specific pixels in each column can be made consistent between the first pixel region and the second pixel region. Therefore, the SN ratio of the spectroscopic spectrum data can be stably improved.

[0017] [9] A spectroscopic device as in [6], wherein the saturation charge amount of each pixel belonging to the first pixel region is different from the saturation charge amount of each pixel belonging to the second pixel region. In this case, spectroscopic spectrum data with a good SN ratio can be obtained in a high dynamic range while keeping the exposure time of each pixel belonging to the first pixel region equal to the exposure time of each pixel belonging to the second pixel region.

[0018]

[10] A spectroscopic device as in [9], wherein the pixel portion has a mask that makes the light receiving area of ​​the first pixel region equal to the light receiving area of ​​the second pixel region. In order to expand the dynamic range, it is desired to increase the difference between the saturation charge amount of the first pixel region and the saturation charge amount of the second pixel region, and it is considered that the size difference between the light receiving area of ​​the first pixel region and the light receiving area of ​​the second pixel region is enlarged in the structure of the image sensor. In this regard, by using a mask that makes the area of ​​the light receiving area of ​​the first pixel region equal to the area of ​​the light receiving area of ​​the second pixel region, the amount of light received per unit time of the two can be made equal. Thus, while the exposure time of each pixel belonging to the first pixel region and the exposure time of each pixel belonging to the second pixel region remain equal, spectroscopic spectrum data with a good SN ratio can be obtained in a higher dynamic range.

[0019]

[11] The spectroscopic device according to any one of [1] to

[10] , further comprising an analysis unit for analyzing the spectroscopic spectrum data. In this case, the spectroscopic device is provided with a function for analyzing the spectroscopic spectrum data, thereby improving convenience.

[0020]

[12] The spectroscopic device according to any one of [1] to

[11] , further comprising the spectroscopic optical system including the spectroscopic element. In this case, the spectroscopic device has a wavelength separation function of light, thereby improving convenience.

[0021]

[13] A Raman spectrometry device comprising: a spectrometer according to any one of [1] to

[12] ; a light source unit that generates light to be irradiated onto a sample; and a light guiding optical system that guides Raman scattered light generated by irradiating the sample with the light to the spectrometer.

[0022] In the Raman spectrometry device, a pixel that forms a spectral spectrum image of Raman scattered light decomposed by wavelength is identified as a specific pixel, and the pixel values ​​of the specific pixels belonging to the same column are integrated to generate spectral spectrum data. By excluding other pixels that do not form a spectral spectrum image from the integration of pixel values, the influence of read noise of each pixel when integrating pixel values ​​can be sufficiently reduced. Therefore, in the Raman spectrometry device, spectral spectrum data of Raman scattered light can be obtained with an excellent SN ratio.

[0023]

[14] A spectroscopic method, which receives light decomposed by wavelength along a specified direction and obtains spectroscopic spectrum data of the light, and comprises: a light receiving step, using a CMOS image sensor to receive the light decomposed by wavelength with a plurality of pixels arranged in a row direction along the wavelength decomposition direction and in a column direction perpendicular to the row direction, and converting the light into an electrical signal; a specific step, specifying a pixel among a plurality of pixels that images the spectroscopic spectrum of the light as a specific pixel; and a generating step, integrating the pixel values ​​of the specific pixels belonging to the same column, and generating spectroscopic spectrum data based on the integration result.

[0024] In this spectroscopic method, a pixel that images a spectroscopic spectrum image of light decomposed by wavelength is specifically identified as a specific pixel, and the pixel values ​​of the specific pixels belonging to the same column are integrated to generate spectroscopic spectrum data. By excluding other pixels that do not image the spectroscopic spectrum image from the integration of pixel values, the influence of readout noise of each pixel when integrating pixel values ​​can be sufficiently reduced. Therefore, in this spectroscopic method, spectroscopic spectrum data can be obtained with an excellent SN ratio. Effects of the Invention

[0025] According to the present disclosure, spectroscopic spectrum data can be acquired with an excellent SN ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a block diagram showing the structure of a Raman spectrometer according to one embodiment of the present disclosure. Figure 2 This is a diagram showing an example of the structure of an imaging sensor. Figure 3 It is a schematic diagram showing the relationship between the exposure time of each pixel belonging to the first imaging area and the exposure time of each pixel belonging to the second imaging area. Figure 4 This is a schematic diagram showing an example of a specific pixel map. Figure 5 is a schematic diagram showing details of a particular pixel map. Figure 6 is a schematic diagram showing details of a readout noise graph. Figure 7 1 is a flowchart showing a spectroscopic method according to an embodiment of the present disclosure. Figure 8 (a) is a schematic diagram showing an example of a spectral image with aberration. Figure 8 (b) shows that based on Figure 8 Schematic diagram of an example of spectral spectrum data obtained by using the spectral spectrum image shown in (a). Fig. 9 It is a schematic diagram showing an example of an integration ratio graph. Fig.10is a schematic diagram showing spectroscopic spectrum data obtained by vertical binning using an integrated ratio graph. Fig.11 (a) to (c) are schematic diagrams showing how spectroscopic spectrum data is generated according to a modification example. Fig.12 Schematic diagram showing a variation of a pixel portion. DETAILED DESCRIPTION

[0027] Hereinafter, preferred embodiments of a spectroscopic device, a Raman spectrometry device, and a spectroscopic method according to one aspect of the present disclosure will be described in detail with reference to the drawings.

[0028] Figure 1 1 is a block diagram showing the structure of a Raman spectrometer according to an embodiment of the present disclosure. The Raman spectrometer 1 is a device for measuring the physical properties of a sample S using Raman scattered light Lr. In the Raman spectrometer 1, light L1 from a light source unit 2 is irradiated onto the sample S, and the Raman scattered light Lr generated by the interaction between the light L1 and the sample S is detected by a spectrometer 5, and spectroscopic spectrum data of the Raman scattered light Lr is obtained. By analyzing the spectroscopic spectrum data obtained by the spectrometer 5 using a computer 6, various physical properties of the sample S, such as the molecular structure, crystallinity, orientation, and distortion amount, can be evaluated. Examples of the sample S include semiconductor materials, polymers, cells, and pharmaceuticals.

[0029] Raman spectrometry device 1 Figure 1 As shown in the figure, the light source unit 2, the light guide optical system 3, the spectroscopic optical system 4, the spectroscopic device 5, the computer 6, and the display unit 7 are provided. In the following description, for convenience of description, the light incident on the spectroscopic device 5 via the spectroscopic optical system 4 is sometimes distinguished from the Raman scattered light Lr and referred to as light L1. In the spectroscopic device 5 incorporated in the Raman spectrometry device 1, the light L1 refers to the Raman scattered light Lr.

[0030] The light source unit 2 is a part that generates the light L0 that is irradiated to the sample S. As the light source constituting the light source unit 2, for example, a laser light source, a light emitting diode, etc. that is an excitation light source for Raman spectroscopy can be used. The light guide optical system 3 is a part that guides the Raman scattered light Lr generated by irradiating the sample S with the light L0 to the spectroscopic device 5. The light guide optical system 3 is composed of, for example, a collimating lens, one or more reflective mirrors, a slot, etc.

[0031] The spectroscopic optical system 4 is a part that decomposes the light L1 along a specified direction. The spectroscopic optical system 4 is composed of a spectroscopic element that decomposes the light L1 along a specific wavelength decomposition direction. As the spectroscopic element, for example, a prism, a diffraction grating (Grating), a concave diffraction grating, a crystal spectroscopic element, etc. can be used. The Raman scattered light Lr is split by the spectroscopic optical system 4 and input to the spectroscopic device 5.

[0032] exist Figure 1 In the embodiment, the spectroscopic optical system 4 and the spectroscopic device 5 are configured as separate bodies, but the spectroscopic optical system 4 can be incorporated as a component of the spectroscopic device 5. That is, the spectroscopic device 5 can further include a spectroscopic optical system 4 including a spectroscopic element that splits the light L1 along the wavelength decomposition direction. In this case, by providing the spectroscopic device 5 with a wavelength decomposition function of the light L1, convenience is sought to be improved. The spectroscopic device 5 is a part that receives the light L1 decomposed by the wavelength along a specified direction and outputs the spectroscopic spectrum data of the light L1. In the present embodiment, the spectroscopic device 5 receives the Raman scattered light Lr that is split along a specific wavelength decomposition direction by the spectroscopic optical system 4, and outputs the spectroscopic spectrum data of the Raman scattered light Lr to the computer 6.

[0033] The computer 6 is physically equipped with a storage device such as a RAM, a ROM, a processor such as a CPU (computational circuit), a communication interface, etc. As the computer 6, for example, a personal computer, a cloud server, an intelligent device (a smart phone, a tablet terminal, etc.) can be used. The computer 6 can be connected to the light source unit 2 and the spectrometer 5 of the Raman spectrometry device 1 for information communication, and these components can be controlled comprehensively. The computer 6 also functions as an analysis unit 8 that analyzes the physical properties of the sample S based on the spectroscopic spectrum data received from the spectrometer 5 (generating unit 15). The computer 6 outputs information showing the analysis results in the analysis unit 8 to the display unit 7.

[0034] The spectroscopic device 5 is as follows Figure 1 As shown in the figure, it includes a pixel unit 11, a conversion unit 12, a readout unit 13, a specifying unit 14, and a generating unit 15. The pixel unit 11, the conversion unit 12, and the readout unit 13 are constituted by an imaging sensor 10. As the imaging sensor 10, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor can be cited.

[0035] In the present embodiment, the spectroscopic device 5 is configured as a camera including an image sensor 10, a specific unit 14, and a generating unit 15. Here, the spectroscopic device 5 and the computer 6 are separate bodies, but the spectroscopic device 5 may be configured to include a camera including an image sensor 10, a specific unit 14, and a generating unit 15, and a computer 6 (analyzer 8) connected to the camera through electrical connection or wireless communication so that information can be communicated with each other. In this case, the spectroscopic device 5 is provided with an analysis function of the spectroscopic spectrum data, so as to improve convenience.

[0036] Figure 21 is a diagram showing the structure of an image sensor. As shown in the figure, in the pixel unit 11 of the image sensor 10, a plurality of pixels 21 are arranged in a row direction and a column direction perpendicular to the row direction. Here, the row direction is the wavelength decomposition direction of the light L1 or the Raman scattered light Lr along the spectroscopic optical system 4, and the column direction is the vertical merging direction described later. Figure 2 In FIG. 1 , for convenience of explanation, 6 rows×7 columns of pixels 21 are illustrated as an example. However, in an actual pixel portion 11 , n rows×m columns of pixels 21 are arranged.

[0037] Each pixel 21 is a part that captures the spectral image of the light L1 or the Raman scattered light Lr formed by the spectroscopic optical system 4. Each pixel 21 has a photodiode 22 and an amplifier 23. The photodiode 22 accumulates electrons (photoelectrons) generated by the input of the light L1 as electric charges. The amplifier 23 converts the electric charges accumulated in the photodiode 22 into an electric signal (for example, a signal indicating a voltage value) and amplifies it.

[0038] The electric signal amplified by the amplifier 23 is transmitted to the vertical signal line 25 connecting the pixels 21 in the row direction by switching the selection switch 24 of each pixel 21. A CDS (correlated double sampling) circuit 26 is arranged on each vertical signal line 25. The CDS circuit 26 reduces the read noise between the pixels 21 and temporarily stores the electric signal transmitted to the vertical signal line 25.

[0039] The conversion unit 12 is a part that converts the voltage value output from the amplifier 23 of each of the plurality of pixels 21 into a digital value. In the present embodiment, the conversion unit 12 is composed of an A / D converter 27. The A / D converter 27 converts the voltage value stored in the CDS circuit 26 into a digital value. The converted digital value (pixel value) is output to the generation unit 15 via the readout unit 13. When the readout unit 13 outputs the pixel value to the generation unit 15, it outputs instruction information for instructing the specific unit 14 to start processing.

[0040] In this embodiment, the pixel portion 11 is as follows Figure 2 As shown in the figure, it has: a first pixel region 21A and a second pixel region 21B divided along the column direction, a first readout section 13A for reading out each pixel 21 belonging to the first pixel region 21A, and a second readout section 13B for reading out each pixel 21 belonging to the second pixel region 21B. Figure 2 In the example, the first pixel region 21A and the second pixel region 21B are divided along the center of the column direction. That is, the pixel 21 on one side of the center in the column direction belongs to the first pixel region 21A, and the pixel 21 on the other side of the center in the column direction belongs to the second pixel region 21B.

[0041] The first readout section 13A and the second readout section 13B are configured independently of each other. The first readout section 13A is connected to the A / D converter 27 corresponding to the vertical signal line 25 of each pixel 21 belonging to the first pixel area 21A. The first readout section 13A outputs the pixel value of each pixel 21 belonging to the first pixel area 21A to the generation section 15. The second readout section 13B is connected to the A / D converter 27 corresponding to the vertical signal line 25 of each pixel 21 belonging to the second pixel area 21B. The second readout section 13B outputs the pixel value of each pixel 21 belonging to the second pixel area 21B to the generation section 15.

[0042] In this embodiment, the first exposure time T1 of each pixel 21 belonging to the first pixel region 21A and the second exposure time T2 of each pixel 21 belonging to the second pixel region 21B are different from each other. Figure 3 As shown, the first exposure time T1 of each pixel 21 belonging to the first pixel region 21A is shorter than the second exposure time T2 of each pixel 21 belonging to the second pixel region 21B. Therefore, during the period in which one frame of image data is obtained in the second pixel region 21B, multiple frames of image data are obtained in the first pixel region 21A. In the generation unit 15, the pixel values ​​corresponding to the multiple frames of image data in the first pixel region 21A are integrated, and image data based on the integrated pixel values ​​is generated. In addition, Figure 3 In the example, the second exposure time T2 is an integer multiple of the first exposure time T1.

[0043] The specific unit 14 and the generating unit 15 are physically constituted by a computer system having a storage device such as RAM, ROM, a processor (calculation circuit) such as CPU, a communication interface, etc. The specific unit 14 and the generating unit 15 can be constituted by a PLC (programmable logic controller) or an FPGA (field-programmable gate array).

[0044] The specific unit 14 is a part that specifies the pixel 21 that images the spectral spectrum image of the light L1 among the plurality of pixels 21 as the specific pixel 21K. When receiving the instruction information from the readout unit 13, the specific unit 14 generates specific information indicating the specific pixel 21K and outputs it to the generating unit 15. The specific unit 14 may retain a specific pixel map M1 for the pixel unit 11 as the specific information. The specific pixel map M1 may be obtained in advance by, for example, simulation data or actual measurement data of a case where the light L1 or the Raman scattered light Lr is guided to the spectroscopic optical system 4.

[0045] Figure 4 is a schematic diagram showing an example of a specific pixel map. Figure 4In the example, for the horizontally long pixel portion 11 having more pixels in the row direction than in the column direction, five spectral images 31 (31A to 31E from the short wavelength side) decomposed by wavelength are imaged. The spectral images 31A to 31E are imaged on the pixel portion 11 in a state where they extend linearly in the column direction of the pixel 21 and are separated from each other in the row direction.

[0046] For the spectral image 31, in the specific pixel map M1, for example, pixels 21 whose imaging area of ​​the spectral image 31 is 50% or more of the area of ​​the light receiving surface are specified as specific pixels 21K. Figure 5 3 rows×3 columns of arbitrary pixels 21 in the specific pixel map M1 are illustrated, and the ratio of the imaging area of ​​the spectral spectrum image 31 to the area of ​​the light receiving surface 21 a of each pixel 21 is displayed.

[0047] exist Figure 5 In the example, the coordinates (x n ,y m+1 ), coordinates(x n ,y m ), coordinates(x n ,y m-1 ) each has an imaging area of ​​100% of the area of ​​the light receiving surface 21a. n-1 ,y m+1 ), coordinates(x n-1 ,y m ), coordinates(x n-1 ,y m-1 ) have imaging areas of spectral images 31 of the three pixels 21 of 15%, 40%, and 65% respectively. n+1 ,y m+1 ), coordinates(x n+1 ,y m ), coordinates(x n+1 ,y m-1 ) have imaging areas of spectral images 31 of 15%, 40%, and 65% respectively. n ,y m+1 ), coordinates(x n ,y m ), coordinates(x n ,y m-1 ), coordinates(x n-1 ,y m-1 ), coordinates(x n+1 ,y m-1 ) are candidates for the specific pixel 21K.

[0048] The specific unit 14 excludes the pixel 21Fa whose readout noise exceeds the threshold value from the specific pixel 21K. The specific unit 14 may retain a readout noise map M2 for the pixel unit 11. The readout noise map M2 is prepared by, for example, measuring the readout noise of each pixel 21 of the pixel unit 11 before the imaging sensor 10 is incorporated into the spectrometer 5. In the present embodiment, the readout noise map M2 is overlapped with the specific pixel map M1 to form a whole (see Figure 4 ).

[0049] In the read noise graph M2, the threshold of the read noise is set to 0.1[e - rms] and above 1.0[e - Based on the read noise map M2, the identifying unit 14 identifies the read noise exceeding 0.1 [e - rms] is excluded from the candidates of the specific pixel 21K. In the present embodiment, the threshold value of the read noise is set to 1.0 [e - rms]. The threshold of the readout noise can be set to 0.5[e - rms], can also be set to 0.3[e - rms]. The threshold of the readout noise can be set to 0.1[e - rms] and above 0.3[e - rms]. In this case, the threshold of the read noise can be set to 0.2[e - rms].

[0050] exist Figure 6 , exemplified Figure 5 3 rows×3 columns of pixels 21 are shown, and the value of the read noise of each pixel 21 is exemplified. Figure 6 In the example, the coordinate (x n-1 ,y m ) and the readout noise of the pixel 21 at the coordinate (x n+1 ,y m-1 ) are 1.4[e - rms], 1.1[e - rms]. When the threshold of the readout noise is set to 1.0[e - rms], these two pixels 21 are pixels 21Fa whose read noise value exceeds the threshold. n+1 ,y m-1 ) of pixels 21 in Figure 5 In the example of , the pixel 21Fa is a candidate for the specific pixel 21K, but the pixel 21Fa has a readout noise exceeding the threshold value, so it is excluded from the candidate for the specific pixel 21K. Figure 5 and Figure 6 Within the range of the pixel 21 shown, the coordinate (x n ,ym+1 ), coordinates(x n ,y m ), coordinates(x n ,y m-1 ), coordinates(x n-1 ,y m-1 ) are finally specified as specific pixels 21K.

[0051] The specific unit 14 may retain in advance the region information indicating the region where no light L1 or Raman scattered light Lr is input in the pixel unit 11, and exclude the pixel 21 corresponding to the region information from the candidate of the specific pixel 21K. The region information is generated in advance based on the specification or configuration of the spectroscopic element in the spectroscopic optical system 4, for example. The region information may be superimposed on the specific pixel map M1. Figure 4 In the example of , the pixels 21 located at both ends of each column belong to the region R where no light L1 is input. The pixels 21Fb belonging to the region R are excluded from the candidates for the specific pixel 21K.

[0052] The generating unit 15 is a part that integrates the pixel values ​​of the specific pixels 21K belonging to the same column and generates spectral spectrum data based on the integration result. The integration of the pixel values ​​of multiple specific pixels 21K belonging to the same column is equivalent to the so-called vertical merging process. The spectral spectrum data can be a two-dimensional image representing the pixel values ​​of each specific pixel 21K, or a histogram plotting pixel values. The generating unit 15 outputs the generated spectral spectrum data to the computer 6 (analyzing unit 8).

[0053] In this embodiment, as described above, the pixel unit 11 is divided into the first pixel region 21A and the second pixel region 21B. In addition, the first exposure time T1 of each pixel 21 belonging to the first pixel region 21A is shorter than the second exposure time T2 of each pixel 21 belonging to the second pixel region 21B (see Figure 2 and Figure 3 The generating unit 15 generates: first spectral spectrum data obtained by integrating pixel values ​​of specific pixels 21K belonging to the same column in the first pixel region 21A, and second spectral spectrum data obtained by integrating pixel values ​​of specific pixels 21K belonging to the same column in the second pixel region 21B.

[0054] The first spectral spectrum data is obtained in the first pixel region 21A at a relatively short first exposure time T1, and is, for example, below the saturation level in all wavelength ranges. The second spectral spectrum data is obtained in the second pixel region 21B at a relatively long second exposure time T2, and is above the saturation level in a certain wavelength range.

[0055] The generating unit 15 divides the wavelength range of the entire spectrum into a saturated wavelength range and a non-saturated wavelength range of the second spectral spectrum data. In the saturated wavelength range, the second spectral spectrum data is above the saturation level, and the first spectral spectrum data does not reach the saturation level. In the non-saturated wavelength range, the second spectral spectrum data does not reach the saturation level and has a better S / N ratio than the first spectral spectrum data. The generating unit 15 combines the first spectral spectrum data of the saturated wavelength range with the second spectral spectrum data of the non-saturated wavelength range to generate spectral spectrum data output to the computer 6.

[0056] Figure 7 1 is a flow chart showing a spectroscopic method according to an embodiment of the present disclosure. The spectroscopic method is a method for receiving light decomposed by wavelength along a predetermined direction and obtaining spectroscopic spectrum data of the light. The spectroscopic method of this embodiment is implemented using the spectroscopic device 5 described above. Figure 7 As shown, the spectroscopic method includes: a light receiving step (step S01), a specifying step (step S02), a generating step (step S03), and an analyzing step (step S4).

[0057] In the light receiving step S01, the imaging sensor 10 (CMOS image sensor) is used to receive the wavelength-decomposed light L1 or Raman scattered light Lr through a plurality of pixels 21 arranged in a row direction along the wavelength decomposition direction and a column direction perpendicular to the row direction, and convert the received light L1 or Raman scattered light Lr into an electrical signal. In the present embodiment, the light L1 or Raman scattered light Lr is received in different exposure periods in the first pixel region 21A and the second pixel region 21B. Then, the pixel values ​​of the pixels 21 belonging to the first pixel region 21A and the pixel values ​​of the pixels 21 belonging to the second pixel region 21B are output to the generating unit 15, respectively.

[0058] In the specific step S02, the pixel 21 that images the spectral spectrum image 31 of the light L1 or the Raman scattered light Lr among the plurality of pixels 21 is identified as the specific pixel 21K. In the present embodiment, the specific unit 14 has a specific pixel map M1 in advance, and the pixel 21 whose imaging area of ​​the spectral spectrum image 31 is 50% or more of the area of ​​the light receiving surface 21a is identified as the specific pixel 21K. In the present embodiment, the read noise is set to a threshold value of 1.0 [e - rms] is excluded from the specific pixel 21K.

[0059] In the generation step S03, the pixel values ​​of the specific pixels 21K belonging to the same column are integrated, and spectral spectrum data based on the integrated result is generated. In this embodiment, the first spectral spectrum data obtained by integrating the pixel values ​​of the specific pixels 21K belonging to the same column in the first pixel area 21A and the second spectral spectrum data obtained by integrating the pixel values ​​of the specific pixels 21K belonging to the same column in the second pixel area 21B are generated in the generation unit 15. In addition, the first spectral data of the saturated wavelength range and the second spectral data of the non-saturated wavelength range are combined to generate the spectral spectrum data output to the computer 6.

[0060] In the analysis step S04, the sample S is analyzed based on the spectral spectrum data generated in the generation step S03. For example, the waveform, peak position, half-width, etc. of the spectral spectrum are analyzed to evaluate various physical properties of the sample S, such as molecular structure, crystallinity, orientation, and distortion amount.

[0061] As described above, in the spectroscopic device 5, the pixel 21 that forms the spectroscopic spectrum image 31 of the wavelength-decomposed light L1 is specifically identified as the specific pixel 21K, and the pixel values ​​of the specific pixels 21K belonging to the same column are integrated to generate the spectroscopic spectrum data. By excluding the other pixels 21 that do not form the spectroscopic spectrum image 31 from the integration of the pixel values, the influence of the read noise when the pixel values ​​are integrated can be sufficiently reduced. Therefore, in the spectroscopic device 5, the spectroscopic spectrum data can be obtained with an excellent SN ratio.

[0062] In the spectroscopic device 5, the pixel 21Fa whose read noise exceeds the threshold value is excluded from the specific pixel 21K. In addition, the threshold value of the read noise is set to 0.1 [e - rms] and above 1.0[e - rms] or less. Thus, the influence of the readout noise when integrating the pixel values ​​can be further reduced. Therefore, the SN ratio of the spectral spectrum data can be further improved.

[0063] In the spectroscopic device 5, the pixel 21 whose imaging area of ​​the specific spectral spectrum image 31 is 50% or more of the area of ​​the light receiving surface 21a is defined as the specific pixel 21K. By excluding the pixel 21 that has a small contribution to the acquisition of the spectral spectrum image 31 from the specific pixel 21K, the influence of the read noise when the pixel value is integrated is further reduced. Therefore, the SN ratio of the spectral spectrum data can be further improved.

[0064] In the spectroscopic device 5, the pixel section 11 includes: a first pixel region 21A and a second pixel region 21B divided along the column direction, a first readout section 13A for reading out each pixel 21 belonging to the first pixel region 21A, and a second readout section 13B for reading out each pixel 21 belonging to the second pixel region 21B. According to such a structure, the first pixel region 21A and the second pixel region 21B can be used respectively according to the method of the spectroscopic spectrum image. Therefore, the spectroscopic spectrum data of various lights can be obtained with a good SN ratio.

[0065] In the spectroscopic device 5, the first exposure time T1 of each pixel 21 belonging to the first pixel region 21A is shorter than the second exposure time T2 of each pixel 21 belonging to the second pixel region 21B. According to this configuration, for example, a spectroscopic spectrum image 31 of light L1 whose intensity varies according to wavelength can be obtained in the first pixel region 21A and the second pixel region 21B at different exposure times. In this embodiment, the saturated wavelength range of the spectroscopic spectrum data obtained in the first pixel region 21A at a relatively short first exposure time T1 and the unsaturated wavelength range of the spectroscopic spectrum data obtained in the second pixel region 21B at a relatively long second exposure time T2 are combined to generate the final spectroscopic spectrum data. Thus, spectroscopic spectrum data with a good SN ratio can be obtained in a high dynamic range.

[0066] In the spectroscopic device 5, the second exposure time T2 is longer than the first exposure time T1, and during the period in which one frame of image data is obtained in the second pixel region 21B, a plurality of frames of image data are obtained in the first pixel region 21A. Thus, even when different exposure times are set in the first pixel region 21A and the second pixel region 21B, the readout noise of each column of specific pixels 21K can be made uniform between the first pixel region 21A and the second pixel region 21B. Therefore, the SN ratio of the spectroscopic spectrum data can be stably improved.

[0067] In the Raman spectrometer 1 incorporating the spectrometer 5, the pixel 21 that forms the spectroscopic spectrum image 31 of the wavelength-decomposed Raman scattered light Lr is identified as a specific pixel 21K, and the pixel values ​​of the specific pixels 21K belonging to the same column are integrated to generate spectroscopic spectrum data. By excluding the other pixels 21 that do not form the spectroscopic spectrum image 31 from the integration of pixel values, the influence of read noise when integrating pixel values ​​can be sufficiently reduced. Therefore, in the Raman spectrometer 1, the spectroscopic spectrum data can be obtained with an excellent SN ratio.

[0068] The present disclosure is not limited to the above-mentioned embodiments, and various changes can be applied. The spectroscopic optical system 4 is composed of a spectroscopic element that splits the light L1 or the Raman scattered light Lr along the wavelength decomposition direction as described above. However, in reality, the spectroscopic spectrum imaged on the pixel unit 11 via the spectroscopic optical system 4 is not linear due to the influence of the aberration of the optical system, as represented by, for example, the Czerny-Turner type of spectrometry.

[0069] In e.g. Figure 8 In the example of (a), the spectral image 31C located at the center of the pixel unit 11 forms a straight line in the column direction (vertical merging direction), but the spectral images 31A, 31B and the spectral images 31D and 31E all have a so-called pincushion-shaped distortion in which the image is bent toward the center of the pixel unit 11. The distortion amount of the spectral image 31 becomes larger as the spectral image is farther away from the center of the pixel unit 11. The distortion amounts of the spectral images 31A and 31E are larger than those of the spectral images 31B and 31D.

[0070] If the pixel values ​​of the specific pixels 21K of each column are vertically merged in the state where such distortion occurs, Figure 8 As shown in (b), among the spectral data 32A to 32E based on the spectral images 31A to 31E, there is a risk that the wavelength resolution in the row direction is reduced according to the degree of distortion in the spectral data 32A, 32B, 32D, and 32E based on the spectral images 31A, 31B, 31D, and 31E except the spectral image 31C. In addition, there is a problem that the SN ratio is reduced due to the reduction of the peak value of the spectral data 32A, 32B, 32D, and 32E.

[0071] In order to solve this problem, it is feasible that the specifying unit 14 specifies the integration ratio of the specific pixel 21K used for the integration of the number of pixels based on the aberration information of the light L1 or the Raman scattered light Lr in the spectroscopic optical system 4, and the generating unit 15 integrates the pixel value of the specific pixel 21K using the integration ratio. Specifically, the specifying unit 14 may be as follows: Fig. 9 As shown in FIG. 1 , there is an integration ratio diagram M3 for the pixel portion 11. Fig. 9 In the example, the integrated ratio map M3 is overlapped with the specific pixel map M1 to form a whole. The aberration information used to generate the integrated ratio map M3 can be obtained in advance by using simulation data or measured data when the light L1 or the Raman scattered light Lr is guided to the spectroscopic optical system 4. When the measured data is used, the aberration information can be obtained based on the spectroscopic spectrum data of multiple light images without local distortion.

[0072] The specific unit 14 can refer to the integration ratio map M3 and perform sub-pixel processing based on the integration ratio of a plurality of specific pixels 21K adjacent to each other in the row direction when vertically combining pixel values. Fig. 9 The integrated ratio of a part of the specific pixel 21K corresponding to the spectral spectrum image 31B and the spectral spectrum image 31E in the integrated ratio diagram M of the entire pixel unit 11 is extracted and displayed. As described above, the distortion of the spectral spectrum image 31E is greater than that of the spectral spectrum image 31B. Therefore, in Fig. 9 In the example of FIG. 3 , in the vertical merging of the pixel values ​​of the specific pixel 21K corresponding to the spectral spectrum image 31B, sub-pixel processing based on the integration ratio of two specific pixels 21K adjacent in the row direction is performed. In addition, in the vertical merging of the pixel 21 corresponding to the spectral spectrum image 31E, sub-pixel processing based on the integration ratio of three specific pixels 21K adjacent in the row direction is performed.

[0073] exist Fig. 9 In the example, the pixel value of the specific pixel 21K with coordinates (x, y) is set to P(x, y). If it is assumed that the reference x coordinate of the specific pixel 21K corresponding to the spectral spectrum image 31B is 300 and the y coordinate is -512 to +512, the vertical combination of the pixel values ​​of the specific pixel 21K corresponding to the spectral spectrum image 31B is expressed by the following formula (1). If it is assumed that the reference x coordinate of the specific pixel 21K corresponding to the spectral spectrum image 31E is 700 and the y coordinate is -512 to +512, the vertical combination of the pixel values ​​of the specific pixel 21K corresponding to the spectral spectrum image 31E is expressed by the following formula (2). [Number 1] [Number 2]

[0074] exist Fig. 9 In FIG. 3 , as a part of the specific pixel 21K corresponding to the spectral spectrum image 31B, four pixels of coordinates (300, -500), coordinates (301, -500), coordinates (300, -501), and coordinates (301, -501) are displayed. For these four pixels, the integration ratio of P(300, -500) is 80%, the integration ratio of P(301, -500) is 20%, the integration ratio of P(300, -501) is 90%, and the integration ratio of P(301, -501) is 10%. Therefore, in equation (1), α(300, -500) is obtained by the following equation (3), and α(300, -501) is obtained by the following equation (4). α(300,-500)=(80×P(300,-500)+20×P(301,-500)) / 100…(3) α(300,-501)=(90×P(300,-501)+10×P(301,-501)) / 100…(4)

[0075] In addition, Fig. 9 In the figure, as part of the specific pixel 21K corresponding to the spectral spectrum image 31E, 9 pixels of coordinates (699,350), coordinates (700,350), coordinates (701,350), coordinates (699,349), coordinates (700,349), coordinates (701,349), coordinates (699,348), coordinates (700,348), and coordinates (701,348) are displayed. For these 9 pixels, the integration ratio of P(699,350) is 15%, the integration ratio of P(700,350) is 70%, the integration ratio of P(701,350) is 15%, the integration ratio of P(699,349) is 20%, the integration ratio of P(700,349) is 70%, the integration ratio of P(701,349) is 10%, the integration ratio of P(699,348) is 25%, the integration ratio of P(700,348) is 70%, and the integration ratio of P(701,348) is 5%.

[0076] Therefore, in equation (2), β(700, 350) is obtained by equation (5) below, β(700, 349) is obtained by equation (6) below, and β(700, 348) is obtained by equation (7) below. β(700,350)=(15×P(699,350)+70×P(700,350)+15×P(701,350))…(5) β(700,349)=(20×P(699,349)+70×P(700,349)+10×P(701,349))…(6) β(700,348)=(25×P(699,348)+70×P(700,348)+5×P(701,348))…(7)

[0077] Fig.10 Schematic diagram showing spectral spectrum data obtained by vertical merging using an integration ratio diagram. As shown in the figure, by integrating the number of pixels of a specific pixel 21K using an integration ratio based on aberration information of light L1 or Raman scattered light Lr, even when distortion occurs in spectral spectrum images 31A to 31E, it is possible to suppress the reduction of wavelength resolution in the row direction in each of spectral spectrum data 32A to 32E based on spectral spectrum images 31A to 31E. In addition, the reduction of the peak value is also suppressed, and the SN ratio is also improved.

[0078] In addition, Fig. 9In the example of FIG. 1 , only the integration ratio map M3 is displayed, but the above-mentioned read noise map M2 may be overlapped in the integration ratio map M3. In addition, the region information may be further overlapped in the integration ratio map M3. In this case, the generation unit 15 excludes the pixel 21 specified by the read noise map M2 and the region information from the specific pixel 21K, and performs vertical merging by sub-pixel processing using the integration ratio map M3.

[0079] In the above embodiment, the first exposure time T1 of each pixel 21 belonging to the first pixel region 21A is shorter than the second exposure time T2 of each pixel 21 belonging to the second pixel region 21B, but a common exposure time may be set in the first pixel region 21A and the second pixel region 21B. When a common exposure time is set, in the pixel unit 11, the saturation charge amount of each pixel 21 belonging to the first pixel region 21A and the saturation charge amount of each pixel 21 belonging to the second pixel region 21B may be different from each other.

[0080] For example, when the saturation charge amount of each pixel 21 belonging to the first pixel region 21A is relatively reduced, the read noise of these pixels 21 is relatively reduced. The first spectroscopic spectrum data obtained by integrating the pixel values ​​of the specific pixels 21K belonging to the same column in the first pixel region 21A is as follows: Fig.11 As shown in (a), the SN ratio is generally good, and the wavelength range with an intensity greater than a specific value is the saturation wavelength range.

[0081] On the other hand, when the saturation charge amount of each pixel 21 belonging to the second pixel region 21B is relatively increased, the read noise of these pixels 21 also becomes relatively large. The second spectroscopic spectrum data obtained by integrating the pixel values ​​of the specific pixels 21K belonging to the same column in the second pixel region 21B is as follows: Fig.11 As shown in (b), the entire spectrum is a non-saturated wavelength range, but the SN ratio decreases in the wavelength range with an intensity below a specific value.

[0082] In this case, the generating unit 15 divides the wavelength range of the entire spectrum into a saturated wavelength range and a non-saturated wavelength range of the first spectrum data. The generating unit 15 combines the first spectrum data of the non-saturated wavelength range with the second spectrum data of the saturated wavelength range, such as Fig.11 Spectral data output to the computer 6 is generated as shown in (c). According to this structure, while keeping the first exposure time T1 of each pixel 21 belonging to the first pixel area 21A and the second exposure time T2 of each pixel 21 belonging to the second pixel area 21B equal to each other, spectral data with a good SN ratio can be obtained in a high dynamic range.

[0083] In order to expand the dynamic range, if the difference between the saturation charge amount of the first pixel region 21A and the saturation charge amount of the second pixel region 21B is to be increased, it is considered that the size difference between the light receiving area of ​​the first pixel region 21A and the light receiving area of ​​the second pixel region 21B is increased in the structure of the image sensor 10. In this case, Fig.12 As shown, a mask 41 is provided in the pixel portion 11 , and the mask 41 makes the area of ​​the light receiving region V1 of the first pixel region 21A and the area of ​​the light receiving region V2 of the second pixel region 21B equal.

[0084] By configuring the mask 41, the amount of light received per unit time of the two can be made equal. Thus, while the exposure time T1 of each pixel 21 belonging to the first pixel region 21A and the exposure time T2 of each pixel 21 belonging to the second pixel region 21B are kept equal, spectral spectrum data with a good SN ratio can be obtained in a higher dynamic range.

[0085] As another variation, the pixel portion 11 may not necessarily be divided into the first pixel region 21A and the second pixel region 21B, and may be composed of one pixel region. The spectrometer 5 is not limited to the application to the Raman spectrometer 1, and may be applied to other spectrometers such as a fluorescence spectrometer, a plasma spectrometer, and a luminescence spectrometer. In addition, the spectrometer 5 may be applied to other spectrometers such as a film thickness measurement device, an optical density measurement, a LIBS (Laser-Induced Breakdown Spectroscopy) measurement, and a DOAS (Differential Optical Absorption Spectroscopy) measurement. Explanation of symbols

[0086] 1…Raman spectrometer; 2…light source; 3…light guiding optical system; 4…spectrometric optical system; 5…spectrometric device; 8…analyzer; 10…image sensor (CMOS image sensor); 11…pixel; 13A…first readout section; 13B…second readout section; 14…specific section; 15…generator; 21…pixel; 21a…light receiving surface; 21A…first pixel region; 21B…second pixel region; 21K…specific pixel; 31 (31A to 31E)…spectrometric spectrum; 41…mask; L1…light; Lr…Raman scattered light; T1…first exposure time; T2…second exposure time; V1…light receiving region of the first pixel region; V2…light receiving region of the second pixel region.

Claims

1. A spectroscopic device, wherein: A spectroscopic device receives light decomposed by wavelength in a predetermined direction by a spectroscopic optical system including a spectroscopic element and obtains spectroscopic spectrum data of the light. It has: a CMOS image sensor, a specific unit, and a generating unit. The CMOS image sensor has a pixel unit having a plurality of pixels that receive the wavelength-decomposed light and convert the light into an electrical signal, and The plurality of pixels are arranged in a row direction along a wavelength separation direction and in a column direction perpendicular to the row direction. The specifying unit specifies, as a specific pixel, a pixel that forms a spectroscopic spectrum image of the light among the plurality of pixels. The generating unit integrates the pixel values ​​of the specific pixels belonging to the same column and generates spectroscopic spectrum data based on the integration result.

2. The spectroscopic device according to claim 1, wherein: The specifying unit excludes pixels having readout noise exceeding a threshold value from the specific pixels.

3. The spectroscopic device according to claim 2, wherein: The threshold of the read noise is set to 0.1[e - rms] and above 1.0[e - rms] range below.

4. The spectroscopic device according to any one of claims 1 to 3, wherein: The specifying unit specifies, as the specific pixel, a pixel whose imaging area of ​​the spectral spectrum image is 50% or more of the area of ​​the light receiving surface.

5. The spectroscopic device according to any one of claims 1 to 3, wherein: The specifying unit specifies the integration ratio of the specific pixel based on the aberration information of the light, The generating unit integrates the pixel value of the specific pixel using the integration ratio.

6. The spectroscopic device according to any one of claims 1 to 3, wherein: The pixel portion has: A first pixel region and a second pixel region, which are divided along the column direction; a first reading unit configured to read out each pixel belonging to the first pixel area; and The second reading unit reads out each pixel belonging to the second pixel area.

7. The spectroscopic device according to claim 6, wherein: A first exposure time of each pixel belonging to the first pixel region is shorter than a second exposure time of each pixel belonging to the second pixel region.

8. The spectroscopic device according to claim 7, wherein: While image data of one frame is being acquired in the second pixel region, image data of a plurality of frames is being acquired in the first pixel region.

9. The spectroscopic device according to claim 6, wherein: The saturation charge amount of each pixel belonging to the first pixel region and the saturation charge amount of each pixel belonging to the second pixel region are different from each other.

10. The spectroscopic device according to claim 9, wherein: The pixel portion includes a mask that makes the area of ​​the light receiving region of the first pixel region equal to the area of ​​the light receiving region of the second pixel region.

11. The spectroscopic device according to any one of claims 1 to 3, wherein: The device further comprises: an analyzing unit configured to analyze the spectroscopic spectrum data.

12. The spectroscopic device according to any one of claims 1 to 3, wherein: The present invention further comprises: the spectroscopic optical system including the spectroscopic element.

13. A Raman spectrometry device, wherein: have: The spectroscopic device according to any one of claims 1 to 3; a light source unit that generates light to irradiate the sample; and The light guide optical system guides the Raman scattered light generated by irradiating the sample with the light to the spectroscopic device.

14. A spectroscopic method, wherein: It is a spectroscopic method that receives light decomposed by wavelength along a specified direction and obtains the spectroscopic spectrum data of the light. have: A light receiving step, using a CMOS image sensor to receive the wavelength-decomposed light with a plurality of pixels arranged in a row direction along the wavelength decomposition direction and in a column direction perpendicular to the row direction, and converting the light into an electrical signal; a specific step of specifying a pixel that images the spectral image of the light from among a plurality of pixels as a specific pixel; and The generating step integrates the pixel values ​​of the specific pixels belonging to the same column and generates spectroscopic spectrum data based on the integration result.

Images