Optical information acquisition device and optical information acquisition method

Abstract

A measurement system 1 comprises: a first line sensor unit that has a first pixel unit 23a in which a plurality of pixels are arranged, detects measurement light from an object S moving relative to the first pixel unit 23a, and outputs a first detection signal; a second line sensor unit that has a second pixel unit 23b in which a plurality of pixels are arranged in parallel with the first pixel unit 23a, and an LRG filter 31 that is disposed so as to cover the second pixel unit 23b and has a characteristic such that the transmittance thereof changes monotonically in accordance with wavelength in a prescribed wavelength band, and the second line sensor unit detects the measurement light from the object S moving relative to the second pixel unit 23b and outputs a second detection signal; and a computer 10 that acquires a characteristic value related to the wavelength spectrum of the measurement light on the basis of at least the first detection signal and the second detection signal.

Description

Optical information acquisition device and optical information acquisition method

[0001] The present invention relates to an optical information acquisition device and an optical information acquisition method.

[0002] Conventionally, measurement devices capable of detecting the centroid wavelength of incident light have been used (see, for example, Patent Document 1). In these measurement devices, an inclined dichroic mirror is used to detect light transmitted through the inclined dichroic mirror and light reflected from the inclined dichroic mirror, and the centroid wavelength of the wavelength spectrum of the incident light is calculated based on the light intensity of each light.

[0003] International Publication No. 2021 / 161684

[0004] While the conventional measurement devices described above can acquire characteristics related to the wavelength spectrum of incident light from an object, there is a need for a device that can acquire characteristics related to the wavelength spectrum of incident light from an object that moves relative to a detection area.

[0005] The present disclosure has been made in consideration of such problems, and aims to provide an optical information acquisition device and an optical information acquisition method that can acquire characteristics related to the wavelength spectrum of incident light from a wide range of objects that move relative to the detection area.

[0006] An optical information acquisition device according to a first aspect of the embodiment includes a first line sensor unit having a first pixel unit in which a plurality of pixels are arranged, which detects measurement light from an object moving relatively to the first pixel unit, and outputs a first detection signal; a second pixel unit having a plurality of pixels arranged in parallel with the first pixel unit; a monotonic function filter arranged to cover the second pixel unit and having a characteristic that transmittance changes monotonically with wavelength in a predetermined wavelength range, which detects measurement light from an object moving relatively to the second pixel unit, and outputs a second detection signal; and a calculation unit that acquires characteristic values ​​related to the wavelength spectrum of the measurement light based on at least the first detection signal and the second detection signal, wherein there is a predetermined time difference between the detection timing of the measurement light of the first line sensor unit and the detection timing of the measurement light of the second line sensor unit.

[0007] Alternatively, an optical information acquisition method according to a second aspect of the embodiment includes a first optical detection step of detecting measurement light from an object moving relatively to the first pixel unit using a first pixel unit having a plurality of pixels arranged thereon and outputting a first detection signal; a second optical detection step of detecting measurement light from an object moving relatively to the second pixel unit using a second pixel unit having a plurality of pixels arranged thereon and a monotonic function filter arranged to cover the second pixel unit and having a characteristic that transmittance changes monotonically depending on wavelength in a predetermined wavelength range and outputting a second detection signal; and a calculation step of acquiring a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal and the second detection signal, wherein there is a predetermined time difference between the detection timing of the measurement light by the first optical detection step and the detection timing of the measurement light by the second optical detection step.

[0008] According to either the first or second aspect, measurement light from an object moving relatively to the first pixel unit is detected by the first pixel unit to output a first detection signal, measurement light from an object moving relatively to the second pixel unit is detected by the second pixel unit after passing through a monotonic function filter to output a second detection signal, and a characteristic value related to the wavelength spectrum of the measurement light is acquired based on the first detection signal and the second detection signal. This makes it possible to acquire a characteristic value related to the wavelength spectrum of measurement light from a wide range of objects moving relatively to the detection region.

[0009] According to any aspect of the present embodiment, it is possible to obtain characteristics related to the width of the wavelength spectrum of incident light.

[0010] FIG. 1 is a schematic diagram of a measurement system 1, which is an optical information acquisition device according to the first embodiment. FIG. 2(a) is a plan view of an imaging device 5 as seen from a direction perpendicular to the light receiving surface, and FIG. 2(b) is a side view of the imaging device 5 as seen from a direction along the light receiving surface. FIG. 3 is a block diagram showing the hardware configuration of the computer 10 in FIG. 1. FIG. 4(a) is a diagram showing an imaging range of an object S, and FIGS. 4(b) to 4(d) are timing charts showing imaging timings of the first pixel unit 23a and the second pixel unit 23b. FIG. 5 is a diagram showing the incident light I to be calculated by the image generation unit 7 in FIG. 1. ０ and transmitted light I １ 6A is a plan view of the image capturing device 5A as viewed from a direction perpendicular to the light receiving surface, and FIG. 6B is a side view of the image capturing device 5A as viewed from a direction along the light receiving surface. ０ , transmitted light I １ , and transmitted light I ２ 8A is a plan view of the image pickup device 5B as seen from a direction perpendicular to the light receiving surface, and FIG. 8B is a side view of the image pickup device 5B as seen from a direction along the light receiving surface. ０ , transmitted light I １ , transmitted light I ２ , and transmitted light I ３ 10A is a plan view of the image pickup device 5C as seen from a direction perpendicular to the light receiving surface, and FIG. 10B is a side view of the image pickup device 5C as seen from a direction along the light receiving surface. FIG. 11 shows the incident state of the incident light I, which is the object of calculation by the image generation unit 7. ０ , transmitted light I １ , transmitted light I ２ , transmitted light I ３ , and transmitted light I ４FIG. 12 is a side view of an imaging device 5D according to a modified example, viewed from a direction along the light receiving surface. FIG. 13 is a timing chart showing imaging timings of the first pixel unit 23a and the second pixel unit 23b in the modified example. FIG. 14 is a diagram showing an example of the transmission characteristics of an LRG filter according to a modified example. FIG. 15 is a diagram showing an example of the transmission characteristics of an LRG filter according to another modified example. FIG. 16 is a diagram showing the configuration of a transport unit 2A according to a modified example. FIG. 17 is a diagram showing the structure of an imaging device 5B.

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted. [First Embodiment]

[0012] FIG. 1 is a schematic diagram of a measurement system 1, which is an optical information acquisition device according to a first embodiment of the present disclosure. The measurement system 1 shown in FIG. 1 is configured as a device that acquires characteristic values ​​related to the wavelength spectrum of measurement light incident from an object S by irradiating the object with light La. As described below, the measurement system 1 uses an optical element having transmission characteristics in which the transmittance changes monotonically with wavelength in a predetermined wavelength range. The measurement system 1 receives, of measurement light Lb from the object S generated by light La, light that has passed through the optical element and light that has not passed through the optical element and is incident. Image data related to the distribution of centroid wavelengths in the object S is then generated based on brightness data based on the respective detection signals obtained as a result of receiving the two types of light. Note that the "centroid wavelength" in this embodiment may also be referred to as the "center wavelength."

[0013] The measurement light Lb is light from the object S, such as light emission, fluorescence, output light, reflected light, or transmitted light from the object S. The object S may be a semiconductor device, a semiconductor wafer, an optical integrated circuit, a light-emitting element, food, a resin material, waste, or a biological sample.

[0014] As shown in Fig. 1, the measurement system 1 includes a transport unit 2, a light source unit 3, an imaging device 5, and a computer (arithmetic unit) 10. The transport unit 2 transports the object S in a predetermined direction. The transport unit 2 is configured, for example, by a belt conveyor. The transport unit 2 transports the object S in the horizontal direction at a constant speed v toward the irradiation position of the light La from the light source unit 3. This causes the object S to be scanned toward the irradiation position of the light La.

[0015] The light source unit 3 is a part that outputs light La toward the target object S. In this embodiment, the light source unit 3 is configured with light source devices 3a and 3b that can output light La toward the target object S from two directions, the upstream side and the downstream side in the conveyance direction. The light La is, for example, a directional light beam. Examples of the light source devices 3a and 3b that output such light include a multi-band LED bar illumination device. The illumination device incorporates, for example, an LED bar with a center wavelength of 1200 nm, an LED bar with a center wavelength of 1300 nm, an LED bar with a center wavelength of 1450 nm, an LED bar with a center wavelength of 1550 nm, and an LED bar with a center wavelength of 1650 nm. The configuration including the two light source devices 3a and 3b can reduce the difference in intensity of the incident measurement light due to differences in the light receiving position or height between the first pixel unit 23a and the second pixel unit 23b (described later).

[0016] 2A is a plan view of the image pickup device 5 as viewed from a direction perpendicular to the light receiving surface, and FIG. 2B is a side view of the image pickup device 5 as viewed from a direction along the light receiving surface. The image pickup device 5 includes a substrate 21, a first pixel unit 23 a, a second pixel unit 23 b, a window unit (plate member) 25, an LRG (Linear Reflectance Gradient on the wavelength axis) filter (monotonous function filter) 31, and AR (Anti-Reflection) coatings 27 and 29.

[0017] The first pixel section 23a is made up of a plurality of pixels 22 linearly arranged on the substrate 21. The second pixel section 23b is made up of a plurality of pixels 22 linearly arranged on the substrate 21 parallel to the first pixel section 23a. The pixel spacing between the first pixel section 23a and the second pixel section on the substrate 21, in other words, the arrangement pitch of the pixels 22 between the first pixel section 23a and the second pixel section, is set to d. The window section 25 is a plate-shaped transparent member made of a material that transmits the measurement light Lb, such as glass, and is arranged so as to entirely cover the first pixel section 23a and the second pixel section 23b on the substrate 21 with a gap therebetween. On the surface of the window section 25 facing the first pixel section 23a and the second pixel section 23b, an LRG filter 31 is formed only in the area covering the second pixel section 23b, and an AR coating 29, which is an anti-reflection film that prevents reflected light, is formed only in the area covering the first pixel section 23a. In addition, an AR coating 27 is formed on the surface of the window portion 25 opposite to the surface facing the first pixel portion 23a and the second pixel portion 23b, in an area that covers the entire first pixel portion 23a and the second pixel portion 23b.

[0018] The imaging device 5 having the above configuration is disposed so that the light receiving side of the substrate 21 faces the object S transported on the transport unit 2, and the arrangement direction of the pixels 22 of the first pixel unit 23 a and the second pixel unit 23 b is perpendicular to the transport direction. The first pixel unit 23 a receives incident light I, which is measurement light Lb from the object S moving relatively to the first pixel unit 23 a. ０ On the other hand, the second pixel unit 23b and the LRG filter 31 detect the incident light I from the object S that moves relative to the second pixel unit 23b, forming a first line sensor unit that outputs a first detection signal. ０ is the transmitted light I that has passed through the LRG filter 31. １ and outputs a second detection signal. The imaging device 5 may include a lens.

[0019] The LRG filter 31 provided in the imaging device 5 is a filter member made of a special optical material, and has a property that the light transmittance in a predetermined wavelength range changes depending on the wavelength, specifically, the light transmittance in a predetermined wavelength range changes linearly with the wavelength. In other words, the LRG filter 31 has a property that the light transmittance in a predetermined wavelength range changes monotonically with the change in wavelength (for example, a property that the transmittance in a predetermined wavelength range increases or decreases monotonically), and has a light transmittance T １ It has the following characteristics. １ (λ) = s １ λ+t １ ... (1) In the above formula (1), s １ , t １ is a known constant determined by the transmittance characteristics. ０ The wavelength range overlaps with the wavelength range of , for example, 400 nm or more and 800 nm or less.

[0020] The computer 10 has a function of controlling the operations of the light source unit 3 and the image pickup device 5, and a function of detecting the incident light I based on the detection signal output from the image pickup device 5. ０and a function to acquire characteristic values ​​related to the wavelength spectrum of the image. FIG. 3 is a block diagram showing the hardware configuration of the computer 10. As shown in FIG. 3, the computer 10 is physically a computer including a processor such as a CPU (Central Processing Unit) 131 and a GPU (Graphic Processing Unit) 135, a storage medium such as a RAM (Random Access Memory) 132 and a ROM (Read Only Memory) 133, a communication module 134, and an input / output module 136, all of which are electrically connected to one another. The computer 10 may include input / output devices such as a display, a keyboard, a mouse, a touch panel display, or a data storage device such as a hard disk drive or semiconductor memory. The computer 10 may also be configured as a microcomputer or an FPGA. The computer 10 may also be configured by multiple computers, or may be integrated with the imaging device 5.

[0021] First, the control function of the computer 10 for the light source unit 3 and the image capture device 5 will be described.

[0022] When measurement of the object S is started, the computer 10 controls the light source unit 3 to output light La of a temporally uniform light intensity toward the object S. Note that the computer 10 may control the light source unit 3 to turn on intermittently so as to synchronize with the image capturing timing of the first pixel unit 23 a and the second pixel unit 23 b described below.

[0023] The computer 10 also controls the imaging timing of the first pixel unit 23 a and the second pixel unit 23 b by outputting control pulses to each of the first pixel unit 23 a and the second pixel unit 23 b. Figure 4 is a diagram for explaining the control of imaging timing by the computer 10, where Figure 4(a) is a diagram showing an imaging range of the object S, and Figures 4(b) and 4(c) are timing charts showing the imaging timing of the first pixel unit 23 a and the second pixel unit 23 b.

[0024] As shown in FIG. 4A , while the object S is being transported by the transport unit 2 so as to move at a speed v relative to the first pixel unit 23 a and the second pixel unit 23 b, the computer 10 controls the image capturing timing, thereby capturing an image for each range (e.g., four ranges indicated by “1” to “4”) divided in the transport direction by the first pixel unit 23 a and the second pixel unit 23 b. In the control shown in FIG. 4B , the computer 10 controls the first pixel unit 23 a and the second pixel unit 23 b to repeatedly detect the measurement light Lb at a period determined by the width of the divided range of the object S and the speed v. At this time, the computer 10 controls the detection start timing of each detection by the second pixel unit 23 b arranged downstream of the transport so that the detection start timing of each detection by the first pixel unit 23 a arranged upstream of the transport is delayed by a time difference (predetermined time difference) ΔT = d / v determined by the transport speed v and the array pitch d. As a result, immediately after the first pixel unit 23a captures each of the ranges "1" to "4," the second pixel unit 23b captures each of the ranges "1" to "4." When the transport direction is reversed, the computer 10 may control the timing of each detection start by the first pixel unit 23a, which is arranged downstream of the transport, to be delayed by a time difference (predetermined time difference) ΔT = d / v determined by the transport speed v and the array pitch d relative to the timing of each detection start by the second pixel unit 23b, which is arranged upstream of the transport. In other words, the computer 10 may control the timing of each detection start by the first pixel unit 23a and the timing of each detection start by the second pixel unit 23b to have a time difference (predetermined time difference) ΔT = d / v determined by the transport speed v and the array pitch d.

[0025] Here, the computer 10 may set the imaging timing of the first pixel unit 23a and the second pixel unit 23b to the timing shown in Figures 4(c) and 4(d). That is, the computer 10 controls the imaging period of the first pixel unit 23a and the second pixel unit 23b to a period ΔT = (1 / n) d / v determined by the transport speed v, the array pitch d, and the integer n, i.e., to set the imaging rate to n v / d. Figure 4(c) shows a control example when n = 1, and Figure 4(d) shows a control example when n = 2. As a result, imaging of the range "1" to "4" by the first pixel unit 23a and imaging of the range "1" to "4" by the second pixel unit 23b are performed simultaneously, and the imaging timing of the same range is shifted by a time difference of n x ΔT between the first pixel unit 23a and the second pixel unit 23b. In other words, the computer 10 may control the timing of the start of detection each time by the first pixel section 23a and the timing of the start of detection each time by the second pixel section 23b so that there is a time difference (predetermined time difference) n·ΔT=n·d / v determined by the transport speed v and the arrangement pitch d.

[0026] Next, the incident light I ０ 1, the computer 10 includes a signal acquisition unit 6, an image generation unit 7, and a display unit 8 as functional components.

[0027] The signal acquisition unit 6 acquires a first detection signal output from the pixel row of the first pixel unit 23 a at each imaging timing, and detects the incident light I incident from the entire object S. ０ The signal acquisition unit 6 acquires second detection signals output from the pixel row of the second pixel unit 23 b at each imaging timing, and generates first image data representing the intensity distribution of the transmitted light I incident from the entire object S. １At this time, the signal acquisition unit 6 may acquire the first detection signal from the first pixel unit 23 a via a delay circuit and a memory (not shown) inside the imaging device 5, thereby synchronizing the output timing of the first detection signal from the first pixel unit 23 a that has detected the range of the object S with the output timing of the second detection signal from the second pixel unit 23 b that has detected the same range of the object S.

[0028] The image generating unit 7 generates an image of the incident light I for each pixel based on the first image data and the second image data. ０ In the following description, the incident light I ０ The light intensity is represented by the symbol I ０ and the transmitted light I １ The light intensity is represented by the symbol I １ Or I Ｔ０ 5 shows the incident light I ０ and transmitted light I １ In this way, the incident light I ０ is the light that does not pass through the LRG filter 31 and enters the image pickup device 5, and the transmitted light I １ is light that passes through the LRG filter 31 and enters the imaging device 5 .

[0029] In detail, the image generating unit 7 generates an image of incident light I ０ The centroid wavelength λ is the first moment in the wavelength spectrum of Ｇ０ That is, the image generating unit 7 has a function of acquiring the light intensity I ０ and the light intensity I indicated by the pixel value of the second image data. １ Based on this, the incident light I ０ Calculate the first moment of the wavelength spectrum of the incident light I ０ The centroid wavelength λ in the wavelength spectrum of Ｇ０ The principle of this function is as follows: ０ The wavelength spectrum of the function i ０ (λ) = I ０ ×f ０ (λ), and the transmitted light I １The wavelength spectrum of the function i １ Assuming that the distribution is (λ), the following equation holds:

[0030] According to the above principle, the image generating unit 7 generates the light intensity I ０ , I １ is expressed by the following formula (2): By substituting into, the centroid wavelength λ Ｇ０ Then, the image generating unit 7 calculates the centroid wavelength λ Ｇ０ The calculation of the incident light I is repeated for each pixel. ０ The centroid wavelength λ is a characteristic value of the wavelength spectrum of Ｇ０ The output image data representing the distribution of

[0031] The display unit 8 outputs the output image data generated by the image generation unit 7. The output destination may be a display, which is an input / output device, or a data recording device such as a hard disk drive or semiconductor memory.

[0032] Next, the procedure of the measurement process of the measurement light from the target S by the measurement system 1 will be described, and the light information acquisition method of this embodiment will be described in detail.

[0033] First, when the transport unit 2 starts transporting the object S, light La is output toward the object S under the control of the computer 10. At the same time, the computer 10 outputs control pulses to each of the first pixel unit 23 a and the second pixel unit 23 b in the imaging device 5, and the imaging timing of each of the first pixel unit 23 a and the second pixel unit 23 b is controlled so that images are captured at timing determined by the transport speed v of the object S and the array pitch d.

[0034] In response to imaging control by the computer 10, first detection signals are output sequentially from the first pixel unit 23a to the computer 10, and first image data is generated by the computer 10 based on the first detection signals output for each pixel row. In parallel with this, second detection signals are output sequentially from the second pixel unit 23b to the computer 10, and second image data is generated by the computer 10 based on the second detection signals output for each pixel row. Next, the computer 10 calculates the incident light I for each pixel based on the first image data and the second image data. ０ The characteristic values ​​of the wavelength spectrum of the incident light I ０ Output image data indicating the distribution of characteristic values ​​relating to the wavelength spectrum is generated and output.

[0035] According to the measurement system 1 according to the first embodiment described above, incident light I from the object S moving relatively to the first pixel unit 23a is ０ is detected by the first pixel unit 23a, a first detection signal is output, and the incident light I from the object S moving relatively to the second pixel unit 23b is ０ is detected by the second pixel unit 23b after passing through the LRG filter 31, and a second detection signal is output. Based on the first detection signal and the second detection signal, the incident light I ０ The distribution of characteristic values ​​relating to the wavelength spectrum of the incident light I from a wide range of the object S moving relatively to the detection area is thereby obtained. ０ It is possible to obtain characteristic values ​​relating to the wavelength spectrum of the light.

[0036] In the first embodiment, the second pixel portion 23b is disposed so as to cover the second pixel portion 23b, and the incident light I ０ The LRG filter 31 may be disposed on a surface of the window 25 that faces the second pixel unit 23b. According to the above-described configuration, the transmitted light I from the object S that has passed through the LRG filter 31 can be easily transmitted. １ can be stably detected by the second pixel portion 23b.

[0037] The configuration of a measurement system according to the second embodiment will be described. The measurement system according to the second embodiment differs from the first embodiment in the configuration of the imaging device 5 and the function of the computer 10. Only the differences between the first embodiment and the second embodiment will be described below.

[0038] 6A and 6B are diagrams showing the configuration of an imaging device 5A according to a second embodiment, with (a) being a plan view seen from a direction perpendicular to the light-receiving surface and (b) being a side view seen from a direction along the light-receiving surface. The imaging device 5A further includes a third pixel section 23c consisting of a plurality of pixels 22 linearly arranged in parallel with the first pixel section 23a and the second pixel section 23b on the substrate 21. The third pixel section 23c is provided adjacent to the second pixel section 23b, but the arrangement order of the first pixel section 23a, the second pixel section 23b, and the third pixel section 23c may be changed to any order.

[0039] The window portion 25 is disposed so as to entirely cover the first pixel portion 23 a, the second pixel portion 23 b, and the third pixel portion 23 c on the substrate 21, with a gap therebetween. A quadratic function filter (first curve function filter) 33 is formed on the surface of the window portion 25 facing the first pixel portion 23 a, the second pixel portion 23 b, and the third pixel portion 23 c only in the area covering the third pixel portion 23 c. An AR coating 27 is formed on the surface of the window portion 25 opposite to the surface facing the first pixel portion 23 a, the second pixel portion 23 b, and the third pixel portion 23 c in the area entirely covering the first pixel portion 23 a, the second pixel portion 23 b, and the third pixel portion 23 c.

[0040] The imaging device 5A having the above configuration is disposed so that the light receiving side of the substrate 21 faces the object S transported on the transport unit 2, and the arrangement direction of the pixels 22 of the first pixel unit 23a, the second pixel unit 23b, and the third pixel unit 23c is perpendicular to the transport direction. The third pixel unit 23c and the quadratic function filter 33 receive incident light I from the object S moving relatively to the third pixel unit 23c. ０ is the transmitted light I transmitted through the quadratic function filter 33. ２ and outputs a third detection signal.

[0041] The quadratic function filter 33 included in the imaging device 5A is a filter member made of a special optical material, and has a property that the transmittance of light in a predetermined wavelength range changes depending on the wavelength, specifically, the transmittance of light in a predetermined wavelength range changes in a curved manner depending on the wavelength. More specifically, the quadratic function filter 33 has a light transmittance T ２ It has the following characteristics. ２ (λ) = r ２ λ ２ +s ２ λ+t ２ ... (3) In the above formula (3), r ２ , s ２ , t ２ is a known constant determined by the transmittance characteristics. The quadratic function filter 33 having the above characteristics can be realized by overlapping two LRG filters. Alternatively, the quadratic function filter 33 may be realized by a single filter.

[0042] The computer 10 according to the second embodiment controls the imaging timing of the first pixel unit 23a, the second pixel unit 23b, and the third pixel unit 23c by outputting control pulses to each of the first pixel unit 23a, the second pixel unit 23b, and the third pixel unit 23c, in the same manner as in the first embodiment. That is, the computer 10 controls the timing of the start of detection for each of the first pixel unit 23a, the second pixel unit 23b, and the third pixel unit 23c so that there is a time difference (predetermined time difference) determined by the transport speed v and the array pitch d. The signal acquisition unit 6 of the computer 10 acquires a third detection signal output from the pixel row of the third pixel unit 23c at each imaging timing, and converts the transmitted light I incident from the entire target S into a signal. ２ and generating third image data representing the intensity distribution of the light beam.

[0043] The image generating unit 7 of the computer 10 generates an image of the incident light I for each pixel based on the first image data, the second image data, and the third image data. ０ In the following description, the transmitted light I２ The light intensity is represented by the symbol I ２ Or I Ｔ１ 7 shows the incident light I ０ , transmitted light I １ , and transmitted light I ２ In this way, the incident light I ０ is the light that does not pass through the LRG filter 31 and the quadratic function filter 33 and enters the image pickup device 5A, and the transmitted light I １ is the light that passes through the LRG filter 31 and enters the image pickup device 5A, and the transmitted light I ２ is the light that passes through the quadratic function filter 33 and enters the imaging device 5A.

[0044] The image generating unit 7 of the computer 10 generates an image of incident light I ０ The standard deviation σ, which is the second moment of the wavelength spectrum of ０ That is, the image generating unit 7 also has a function of acquiring the light intensity I ０ , the light intensity I indicated by the pixel value of the second image data １ , and the light intensity I indicated by the pixel value of the third image data ２ Based on this, the incident light I ０ Calculate the second moment of the wavelength spectrum of the incident light I ０ Standard deviation σ in the wavelength spectrum of ０ Or variance σ ０ ２ The principle of this function is as follows: where the transmitted light I ２ The wavelength spectrum of the function i ２ (λ) = I ２ ×f ２ Assuming that the distribution is (λ), the following equation holds:

[0045] According to the above principle, the image generating unit 7 generates a light intensity I ０ , I ２ is expressed by the following formula (4): By substituting into, the standard deviation σ ０ The image generating unit 7 calculates the standard deviation σ ０ Instead of σ, the variance ０２ The image generating unit 7 may further calculate the incident light I ０ The standard deviation σ, which is a characteristic value of the wavelength spectrum of ０ The output image data representing the distribution of

[0046] According to the measurement system according to the second embodiment described above, incident light I from a wide range of the object S moving relatively to the detection area is ０ The distribution of characteristic values ​​for the wavelength spectrum is expressed as a function of standard deviation σ ０ It is possible to acquire multiple types of information, including the above. [Third embodiment]

[0047] The configuration of a measurement system according to the third embodiment will be described. The measurement system according to the third embodiment differs from the second embodiment in the configuration of the imaging device 5A and the function of the computer 10. Only the differences between the second embodiment and the third embodiment will be described below.

[0048] 8A and 8B are diagrams showing the configuration of an imaging device 5B according to a third embodiment, with (a) being a plan view seen from a direction perpendicular to the light-receiving surface and (b) being a side view seen from a direction along the light-receiving surface. The imaging device 5B further includes a fourth pixel unit 23d consisting of a plurality of pixels 22 linearly arranged in parallel with the first pixel unit 23a, the second pixel unit 23b, and the third pixel unit 23c on the substrate 21. The fourth pixel unit 23d is provided adjacent to the third pixel unit 23c, but the arrangement order of the first pixel unit 23a, the second pixel unit 23b, the third pixel unit 23c, and the fourth pixel unit 23d may be changed to any order.

[0049] The window portion 25 is arranged to entirely cover the first pixel portion 23 a, the second pixel portion 23 b, the third pixel portion 23 c, and the fourth pixel portion 23 d on the substrate 21, with a gap therebetween. A cubic function filter (second curve function filter) 35 is formed on the surface of the window portion 25 facing the first pixel portion 23 a, the second pixel portion 23 b, the third pixel portion 23 c, and the fourth pixel portion 23 d, only in an area covering the fourth pixel portion 23 d. An AR coating 27 is formed on the surface of the window portion 25 opposite to the surface facing the first pixel portion 23 a, the second pixel portion 23 b, the third pixel portion 23 c, and the fourth pixel portion 23 d, in an area covering the entire first pixel portion 23 a, the second pixel portion 23 b, the third pixel portion 23 c, and the fourth pixel portion 23 d.

[0050] The imaging device 5B having the above configuration is arranged so that the light receiving side of the substrate 21 faces the object S transported on the transport unit 2, and the arrangement direction of the pixels 22 of the first pixel unit 23 a, the second pixel unit 23 b, the third pixel unit 23 c, and the fourth pixel unit 23 d is perpendicular to the transport direction. The fourth pixel unit 23 d and the cubic function filter 35 receive incident light I from the object S moving relatively to the fourth pixel unit 23 d. ０ is the transmitted light I transmitted through the cubic function filter 35. ３ and outputs a fourth detection signal.

[0051] The cubic function filter 35 included in the imaging device 5B is a filter member made of a special optical material, and has a property that the transmittance of light in a predetermined wavelength range changes depending on the wavelength, specifically, the transmittance of light in a predetermined wavelength range changes in a curved manner depending on the wavelength. More specifically, the cubic function filter 35 has a light transmittance T ３ It has the following characteristics. ３ (λ) = q ３ λ ３ +r ３ λ ２ +s ３ λ+t ３ ... (5) In the above formula (5), q ３ , r ３ , s ３ , t３ is a known constant determined by the transmittance characteristics. The cubic function filter 35 having the above characteristics can be realized by overlapping three LRG filters. The cubic function filter 35 may also be realized by a single filter, or by overlapping an LRG filter and a quadratic function filter.

[0052] The computer 10 according to the third embodiment controls the imaging timing of the first pixel unit 23a, the second pixel unit 23b, the third pixel unit 23c, and the fourth pixel unit 23d by outputting control pulses to each of the first pixel unit 23a, the second pixel unit 23b, the third pixel unit 23c, and the fourth pixel unit 23d, as in the second embodiment. That is, the computer 10 may control the timing of the start of detection for each of the first pixel unit 23a, the second pixel unit 23b, the third pixel unit 23c, and the fourth pixel unit 23d so that they have a time difference (a predetermined time difference) determined by the transport speed v and the array pitch d. The signal acquisition unit 6 of the computer 10 acquires a fourth detection signal output from the pixel row of the fourth pixel unit 23d at each imaging timing, and converts the transmitted light I incident from the entire target S into a signal. ３ and generating fourth image data representing the intensity distribution of the light beam.

[0053] The image generating unit 7 of the computer 10 generates an image of the incident light I for each pixel based on the first image data, the second image data, the third image data, and the fourth image data. ０ In the following description, the transmitted light I ３ The light intensity is represented by the symbol I ３ Or I Ｔ２ 9 shows the incident light I ０ , transmitted light I １ , transmitted light I ２ , and transmitted light I ３ In this way, the incident light I ０ is the light that does not pass through the LRG filter 31, the quadratic function filter 33, and the cubic function filter 35 and enters the image pickup device 5B, and the transmitted light I１ is the light that passes through the LRG filter 31 and enters the image pickup device 5B, and the transmitted light I ２ is the light that passes through the quadratic function filter 33 and enters the image pickup device 5B, and the transmitted light I ３ is the light that passes through the cubic function filter 35 and enters the image pickup device 5B.

[0054] The image generating unit 7 of the computer 10 generates an image of incident light I ０ The skewness S is the third moment of the wavelength spectrum of ０ That is, the image generating unit 7 also has a function of acquiring the light intensity I ０ , the light intensity I indicated by the pixel value of the second image data １ , the light intensity I indicated by the pixel value of the third image data ２ , and the light intensity I indicated by the pixel value of the fourth image data ３ Based on this, the incident light I ０ Calculate the third moment of the wavelength spectrum of the incident light I ０ The skewness S in the wavelength spectrum of ０ The principle of this function is as follows: where the transmitted light I ３ The wavelength spectrum of the function i ３ (λ) = I ３ ×f ３ Assuming that the distribution is (λ), the following equation holds:

[0055] According to the above principle, the image generating unit 7 generates a light intensity I ０ , I ３ is expressed by the following formula (6): By substituting into, the skewness S ０ The image generating unit 7 further calculates the incident light I ０ The skewness S, which is a characteristic value of the wavelength spectrum ０ The output image data representing the distribution of

[0056] According to the measurement system according to the third embodiment described above, incident light I from a wide range of the object S moving relatively to the detection area is ０ The distribution of characteristic values ​​for the wavelength spectrum is expressed as a function of standard deviation σ ０and skewness S ０ [Fourth embodiment]

[0057] The configuration of a measurement system according to the fourth embodiment will be described. The measurement system according to the fourth embodiment differs from the third embodiment in the configuration of the imaging device 5B and the function of the computer 10. Only the differences between the fourth embodiment and the third embodiment will be described below.

[0058] 10 shows the configuration of an imaging device 5C according to a fourth embodiment, with (a) being a plan view seen from a direction perpendicular to the light-receiving surface and (b) being a side view seen from a direction along the light-receiving surface. The imaging device 5C further includes a fifth pixel section 23e consisting of a plurality of pixels 22 linearly arranged in parallel with the first pixel section 23a, the second pixel section 23b, the third pixel section 23c, and the fourth pixel section 23d on the substrate 21. The fifth pixel section 23e is provided adjacent to the fourth pixel section 23d, but the arrangement order of the first pixel section 23a, the second pixel section 23b, the third pixel section 23c, the fourth pixel section 23d, and the fifth pixel section 23e may be changed to any order.

[0059] The window portion 25 is disposed so as to entirely cover, with a gap therebetween, the first pixel portion 23 a, the second pixel portion 23 b, the third pixel portion 23 c, the fourth pixel portion 23 d, and the fifth pixel portion 23 e on the substrate 21. A quartic function filter (third curve function filter) 37 is formed on the surface of the window portion 25 facing the first pixel portion 23 a, the second pixel portion 23 b, the third pixel portion 23 c, the fourth pixel portion 23 d, and the fifth pixel portion 23 e, only in the range covering the fifth pixel portion 23 e. On the surface of the window portion 25 opposite to the surface facing the first pixel portion 23 a, the second pixel portion 23 b, the third pixel portion 23 c, the fourth pixel portion 23 d, and the fifth pixel portion 23 e, an AR coating 27 is formed in an area covering the entire first pixel portion 23 a, the second pixel portion 23 b, the third pixel portion 23 c, the fourth pixel portion 23 d, and the fifth pixel portion 23 e.

[0060] The imaging device 5C having the above configuration is arranged so that the light receiving side of the substrate 21 faces the object S transported on the transport unit 2, and the arrangement direction of the pixels 22 of the first pixel unit 23a, the second pixel unit 23b, the third pixel unit 23c, the fourth pixel unit 23d, and the fifth pixel unit 23e is perpendicular to the transport direction. The fifth pixel unit 23e and the quartic function filter 37 receive incident light I from the object S moving relatively to the fifth pixel unit 23e. ０ is the transmitted light I transmitted through the quartic function filter 37. ４ and outputs a fifth detection signal.

[0061] The quartic function filter 37 included in the imaging device 5C is a filter member made of a special optical material, and has a property that the transmittance of light in a predetermined wavelength range changes depending on the wavelength, specifically, the transmittance of light in a predetermined wavelength range changes in a curved manner depending on the wavelength. More specifically, the quartic function filter 37 has a light transmittance T ４ It has the following characteristics. ４ (λ) = p ４ λ ４ +q ４ λ ３ +r ４ λ ２ +s ４ λ+t ４ ... (7) In the above formula (7), p ４ , q ４ , r ４ , s ４ , t ４ is a known constant determined by the transmittance characteristics. The quartic function filter 37 having the above characteristics can be realized by overlapping four LRG filters. The quartic function filter 37 may be realized by a single filter, by overlapping an LRG filter and a cubic function filter, or by overlapping two quadratic function filters.

[0062] The computer 10 according to the fourth embodiment controls the imaging timing of the first pixel unit 23 a, the second pixel unit 23 b, the third pixel unit 23 c, the fourth pixel unit 23 d, and the fifth pixel unit 23 e, by outputting control pulses to each of the first pixel unit 23 a, the second pixel unit 23 b, the third pixel unit 23 c, the fourth pixel unit 23 d, and the fifth pixel unit 23 e, in the same manner as in the third embodiment. That is, the computer 10 may control the timing of the start of detection for each of the first pixel unit 23 a, the second pixel unit 23 b, the third pixel unit 23 c, the fourth pixel unit 23 d, and the fifth pixel unit 23 e so that there is a time difference (predetermined time difference) between them that is determined by the transport speed v and the array pitch d. The signal acquisition unit 6 of the computer 10 acquires a fifth detection signal output from the pixel row of the fifth pixel unit 23e at each imaging timing, and calculates the transmitted light I incident from the entire object S. ４ A fifth image data representing the intensity distribution of the light is generated.

[0063] The image generating unit 7 of the computer 10 generates an image of the incident light I for each pixel based on the first image data, the second image data, the third image data, the fourth image data, and the fifth image data. ０ In the following description, the transmitted light I ４ The light intensity is represented by the symbol I ４ Or I Ｔ３ 11 shows the incident light I ０ , transmitted light I １ , transmitted light I ２ , transmitted light I ３ , and transmitted light I ４ In this way, the incident light I ０ is light that does not pass through the LRG filter 31, the quadratic function filter 33, the cubic function filter 35, and the quartic function filter 37 and enters the image pickup device 5C, and transmitted light I １ is the light that passes through the LRG filter 31 and enters the image pickup device 5C, and the transmitted light I ２ is the light that passes through the quadratic function filter 33 and enters the image pickup device 5C, and the transmitted light I３ is the light that passes through the cubic function filter 35 and enters the image pickup device 5C, and the transmitted light I ４ is the light that passes through the quartic function filter 37 and enters the image pickup device 5C.

[0064] The image generating unit 7 of the computer 10 generates an image of incident light I ０ The kurtosis K is the fourth moment of the wavelength spectrum of ０ That is, the image generating unit 7 also has a function of acquiring the light intensity I ０ , the light intensity I indicated by the pixel value of the second image data １ , the light intensity I indicated by the pixel value of the third image data ２ , the light intensity I indicated by the pixel value of the fourth image data ３ , and the light intensity I indicated by the pixel value of the fifth image data ４ Based on this, the incident light I ０ Calculate the fourth moment of the wavelength spectrum of the incident light I ０ Kurtosis K in the wavelength spectrum of ０ The principle of this function is as follows: where the transmitted light I ４ The wavelength spectrum of the function i ４ (λ) = I ４ ×f ４ Assuming that the distribution is (λ), the following equation holds:

[0065] According to the above principle, the image generating unit 7 generates a light intensity I ０ , I ４ is expressed by the following formula (8): By substituting into, the kurtosis K ０ The image generating unit 7 further calculates the incident light I ０ The kurtosis K is a characteristic value of the wavelength spectrum of ０ The output image data representing the distribution of

[0066] According to the measurement system according to the fourth embodiment described above, incident light I from a wide range of the object S moving relatively to the detection area is ０ The distribution of characteristic values ​​for the wavelength spectrum is expressed as a function of standard deviation σ ０ , skewness S ０, and kurtosis K ０ [Modifications]

[0067] Although various embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments.

[0068] In the imaging devices 5, 5A, 5B, and 5C according to the first to fourth embodiments, the LRG filter, the quadratic function filter 33, the cubic function filter 35, or the quartic function filter 37 is disposed on the window portion 25, but these filters may be disposed on any one of the first pixel portion 23 a, the second pixel portion 23 b, the third pixel portion 23 c, the fourth pixel portion 23 d, and the fifth pixel portion 23 e.

[0069] The imaging device 5 according to the first embodiment may be modified to have the configuration of an imaging device 5D as shown in Fig. 12. In the imaging device 5D, the upper part of the AR coating 29 on the surface of the window 25 facing the first pixel portion 23a is coated with an AR coating 29 to cover only the first pixel portion 23a. ０ A light-reducing filter 39 is provided to reduce the light.

[0070] With this configuration, it is possible to reduce the difference in intensity of the measurement light detected by the first pixel portion 23a and the second pixel portion 23b, and to prevent saturation of the first detection signal. ０ It is possible to accurately obtain characteristic values ​​relating to the wavelength spectrum of the incident light. For example, in order to ensure a sufficient amount of light detection by the second pixel unit 23b, it is necessary to increase the intensity of the light La from the light source unit 3. In this case, if the intensity of the light La is increased, each pixel of the first pixel unit 23a may be saturated. The configuration of the imaging device 5D makes it possible to prevent pixel saturation. When the configuration of the above modified example is adopted, the image generating unit 7 of the computer 10 detects the incident light I through the neutral density filter 39. ０ In the case of a configuration in which the intensity of is multiplied by a (0<a<1), when calculating the characteristic value, the intensity a×I obtained from the first detection signal is ０ Based on the strength I ０ is calculated and then the calculation is performed.

[0071] The configuration of the imaging device 5D according to the above modification may also be applied to the second to fourth embodiments.

[0072] In the measurement systems according to the first to fourth embodiments, in order to prevent saturation of the first detection signal, the computer 10 may control the first pixel unit 23 a and the second pixel unit 23 b so that the exposure time for one image capture is different. ０ The exposure time for one detection is １ 13 shows the image capturing timing of the first pixel unit 23a and the second pixel unit 23b controlled by the computer 10, and shows a control example corresponding to the control example shown in FIGS. 4(c) and 4(d). In this case, too, the incident light I ０ However, in this case, as in the above-described modified example, the image generating unit 7 of the computer 10 converts the value obtained from the first detection signal into the intensity I ０ The characteristic value is calculated after correcting the error.

[0073] In the first to fourth embodiments, the imaging devices 5, 5A, 5B, and 5C or the computer 10 may have a region of interest (ROI) function for selecting pixels from the first pixel to the last pixel from which a detection signal is to be acquired from the pixel row constituting the first pixel unit 23a, the second pixel unit 23b, the third pixel unit 23c, or the fourth pixel unit 23d. With this ROI function, even if the positions of the pixel units are misaligned in the pixel array direction on the substrate 21, it is possible to adjust the detection range for the object S, and accurately detect the incident light I. ０ It is possible to calculate characteristic values ​​related to the wavelength spectrum.

[0074] In the first to fourth embodiments, the imaging devices 5, 5A, 5B, 5C or the computer 10 may perform FFC (flat field correction) on the detection signals acquired from multiple pixel units in order to correct luminance unevenness, color unevenness of the light source unit 3, or errors in the spectral sensitivity of the line sensor unit itself.

[0075] Furthermore, in the first to fourth embodiments, the LRG filter 31 may have transmission characteristics in which the transmittance changes linearly in each of a plurality of different wavelength regions, as shown in Fig. 14. Such transmission characteristics may be realized by designing a dielectric multilayer film of a single inclined dichroic mirror, or may be realized by stacking a plurality of inclined dichroic mirrors or by switching between them using a filter changer.

[0076] In the example of FIG. 14, the central wavelength λ １ A wavelength region including the center wavelength λ ３ and a wavelength range including the center wavelength λ ５ The transmittance of the LRG filter 31 varies linearly and independently for wavelength regions including the wavelengths I and II. In this case, the transmittance of the LRG filter 31 varies from near 0% to near 100% in each wavelength region, so the gradient of the change in the transmittance of the LRG filter 31 for each wavelength region is greater than in the examples of the first to fourth embodiments. As the gradient of the change in the transmittance of the LRG filter 31 is greater, the change in the relative value between the transmittance and the reflectance increases with the amount of wavelength shift when a wavelength shift occurs. This improves the wavelength resolution of the centroid wavelength. Therefore, the incident light I on the object S ０ Therefore, the characteristic values ​​relating to the wavelength spectrum can be obtained with higher accuracy.

[0077] 15, the LRG filter 31 may have transmission characteristics in which wavelength regions in which the transmittance increases linearly and wavelength regions in which the transmittance decreases linearly alternately. １ The transmittance of the LRG filter 31 increases linearly in the wavelength region including the center wavelength λ ３ In the wavelength region including the center wavelength λ ５ The transmittance of the LRG filter 31 increases linearly in the wavelength region including the wavelengths of the LRG filters 31. The dielectric multilayer film of such an LRG filter 31 can be designed more simply than that of the LRG filter 31 having the transmission characteristics shown in FIG.

[0078] Furthermore, in the first to fourth embodiments, the transport unit 2 may be modified to have the configuration of a transport unit 2A as shown in FIG. 16 . The transport unit 2A includes an XY stage 2a arranged to face the imaging devices 5, 5A to 5C. The target object S is placed on the XY stage 2a. When measuring the target object S, the XY stage 2a operates to move the imaging region IR formed by the first pixel unit 23a, the second pixel unit 23b, etc., at a predetermined speed v in the Y-axis direction intersecting the pixel arrangement direction of the first pixel unit 23a, shift it in the X-axis direction, and then move it again in the Y-axis direction. This allows the measurement range of the target object S to be scanned over the surface of the target S.

[0079] In the first to fourth embodiments, some of the functions of the computer 10 may be executed by the imaging device 5 .

[0080] The imaging devices 5, 5A to 5C of the first to fourth embodiments are realized, for example, by the structure shown in Fig. 17. Fig. 17 shows an example of the structure of an imaging device 5B.

[0081] As shown in FIG. 17 , the imaging device 5B includes a pixel unit 41 and a data readout unit 43. The pixel unit 41 and the data readout unit 43 are formed on a single chip and integrated with each other. The pixel unit 41 is configured by N (N is an integer of 2 or greater, for example, 4) × M (M is an integer of 2 or greater) pixels 22 that perform photoelectric conversion, arranged in a two-dimensional matrix. Four columns of the pixel array 12, each consisting of M columns of pixels, respectively constitute a first pixel portion 23 a, a second pixel portion 23 b, a third pixel portion 23 c, and a fourth pixel portion 23 d. Each pixel 22 is formed, for example, in a rectangular shape in a plan view.

[0082] Each pixel 22 is electrically connected to the data readout unit 43 via the wiring unit 42. When an image is captured by each pixel array 12 under the control of the image capture timing by the computer 10 as described above, a charge signal corresponding to light detected in the pixel 22 included in each pixel array 12 is output to the data readout unit 43. The data readout unit 43 converts the charge signal output from the pixel 22 included in each pixel array 12 into a digital value and outputs it to the computer 10 as a detection signal.

[0083] In the first aspect, the first line sensor unit may further include a neutral density filter disposed to cover the first pixel unit and configured to attenuate the measurement light. This reduces the difference in intensity of the measurement light detected by the first pixel unit and the second pixel unit, thereby preventing saturation of the first detection signal. As a result, it is possible to accurately obtain a characteristic value related to the wavelength spectrum of the measurement light.

[0084] In the first aspect, the exposure time for one detection of the measurement light in the first line sensor unit may be set shorter than the exposure time for one detection of the measurement light in the second line sensor unit. This configuration can reduce the difference in intensity of the measurement light detected by the first pixel unit and the second pixel unit, thereby preventing saturation of the first detection signal. As a result, it is possible to accurately obtain a characteristic value related to the wavelength spectrum of the measurement light.

[0085] In the first aspect, the optical element may further include a plate member that is arranged to cover the second pixel unit and that transmits the measurement light, and the monotonic function filter is arranged on a surface of the plate member that faces the second pixel unit. With this configuration, the measurement light from the object that has transmitted through the monotonic function filter can be stably detected by the second pixel unit with a simple configuration.

[0086] In the first aspect, the optical fiber optical system may further include a third line sensor unit including a third pixel unit having a plurality of pixels arranged in parallel with the first pixel unit and the second pixel unit, and a first curve function filter arranged to cover the third pixel unit and having a transmittance that changes curvedly with wavelength in a predetermined wavelength range, the third line sensor unit detecting measurement light from an object moving relative to the third pixel unit and outputting a third detection signal, wherein the calculation unit may further include a third light detection step of detecting measurement light from an object moving relative to the third pixel unit using the third pixel unit having a plurality of pixels arranged in parallel with the first pixel unit and the second pixel unit, and the first curve function filter arranged to cover the third pixel unit and having a transmittance that changes curvedly with wavelength in a predetermined wavelength range, and outputting a third detection signal, wherein the calculation step may further include a third light detection step of detecting measurement light from an object moving relative to the third pixel unit using the third pixel unit having a plurality of pixels arranged in parallel with the first pixel unit and the second pixel unit, the first curve function filter arranged to cover the third pixel unit and having a transmittance that changes curvedly with wavelength in a predetermined wavelength range, and outputting a third detection signal, wherein the calculation step may further include a third light detection step of detecting measurement light from an object moving relative to the third pixel unit using the third pixel unit having a plurality of pixels arranged in parallel with the first pixel unit and the second pixel unit With this configuration, it is possible to acquire a plurality of types of characteristics relating to the wavelength spectrum of measurement light from a wide range of an object that moves relatively to the detection region.

[0087] In the first aspect, the first curved line function filter may be a filter formed by stacking two monotonic function filters each having a characteristic that transmittance changes monotonically with wavelength in a predetermined wavelength range. With this configuration, the first curved line function filter can be realized with a simple configuration.

[0088] In the first aspect, the optical element further includes a fourth line sensor unit that has a fourth pixel unit in which a plurality of pixels are arranged in parallel with the first pixel unit, the second pixel unit, and the third pixel unit, and a second curve function filter that is arranged to cover the fourth pixel unit and has a characteristic that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and that detects measurement light from an object that moves relative to the fourth pixel unit and outputs a fourth detection signal, and the calculation unit may acquire a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal, the second detection signal, the third detection signal, and the fourth detection signal. In the second aspect, the present invention may further include a fourth light detection step of detecting measurement light from an object moving relatively to the fourth pixel unit using a fourth pixel unit having an array of multiple pixels and a second curve function filter arranged to cover the fourth pixel unit and having a characteristic that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and outputting a fourth detection signal, and the calculation step may acquire a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal, the second detection signal, the third detection signal, and the fourth detection signal. In this case, it is possible to acquire more types of characteristics related to the wavelength spectrum of the measurement light from a wide range of the object moving relatively to the detection region.

[0089] In the first aspect, the second curved line function filter may be a filter formed by stacking three monotonic function filters each having a characteristic that transmittance changes monotonically with wavelength in a predetermined wavelength range. With this configuration, the second curved line function filter can be realized with a simple configuration.

[0090] In the first aspect, the optical element further includes a fifth pixel unit having a plurality of pixels arranged in parallel with the first pixel unit, the second pixel unit, the third pixel unit, and the fourth pixel unit, and a third curve function filter arranged to cover the fifth pixel unit and having a characteristic that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and a fifth line sensor unit that detects measurement light from an object moving relative to the fifth pixel unit and outputs a fifth detection signal, and the calculation unit may acquire a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal, the second detection signal, the third detection signal, the fourth detection signal, and the fifth detection signal. In the second aspect, the method may further include a fifth light detection step of detecting measurement light from an object moving relatively to the fifth pixel unit using a fifth pixel unit having an array of multiple pixels and a third curve function filter arranged to cover the fifth pixel unit and having a characteristic that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and outputting a fifth detection signal, and the calculation step may acquire a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal, the second detection signal, the third detection signal, the fourth detection signal, and the fifth detection signal. With this configuration, it is possible to acquire even more types of characteristics related to the wavelength spectrum of the measurement light from a wide range of the object moving relatively to the detection area.

[0091] In the first aspect, the third curve function filter may be a filter formed by stacking four monotonic function filters each having a characteristic that transmittance changes monotonically with wavelength in a predetermined wavelength range. With this configuration, the third curve function filter can be realized with a simple configuration.

[0092] The optical information acquisition device of the embodiment is [1] "an optical information acquisition device comprising: a first line sensor unit having a first pixel unit in which a plurality of pixels are arranged, detecting measurement light from an object moving relatively to the first pixel unit, and outputting a first detection signal; a second pixel unit having a plurality of pixels arranged in parallel with the first pixel unit, and a monotonic function filter arranged to cover the second pixel unit and having a characteristic that transmittance changes monotonically depending on wavelength in a predetermined wavelength range, detecting measurement light from an object moving relatively to the second pixel unit, and outputting a second detection signal; and a calculation unit that acquires a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal and the second detection signal, wherein there is a predetermined time difference between the detection timing of the measurement light of the first line sensor unit and the detection timing of the measurement light of the second line sensor unit."

[0093] The optical information acquisition device of the embodiment may be [2] "the optical information acquisition device described in [1] above, wherein the first line sensor unit is arranged to cover the first pixel unit and further has a neutral density filter that attenuates the measurement light."

[0094] The optical information acquisition device of the embodiment may be [3] "the optical information acquisition device described in [1] or [2] above, wherein the exposure time for one detection of the measurement light in the first line sensor unit is set shorter than the exposure time for one detection of the measurement light in the second line sensor unit."

[0095] The optical information acquisition device of the embodiment may be [4] "the optical information acquisition device described in any one of [1] to [3] above, further comprising a plate member arranged to cover the second pixel unit and transmitting the measurement light, and the monotonic function filter is arranged on a surface of the plate member facing the second pixel unit."

[0096] The optical information acquisition device of the embodiment may be [5] "the optical information acquisition device according to any one of the above [1] to [4], further comprising a third line sensor unit that includes a third pixel unit having a plurality of pixels arranged in parallel with the first pixel unit and the second pixel unit, and a first curve function filter that is arranged to cover the third pixel unit and has a characteristic that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and detects measurement light from an object that moves relatively to the third pixel unit and outputs a third detection signal, and the calculation unit acquires a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal, the second detection signal, and the third detection signal."

[0097] The optical information acquisition device of the embodiment may be [6] "the optical information acquisition device described in [5] above, wherein the first curve function filter is a filter made by stacking two monotonic function filters having a characteristic that the transmittance changes monotonically depending on the wavelength in a predetermined wavelength range."

[0098] The optical information acquisition device of the embodiment may be [7] "the optical information acquisition device described in [5] above, which has a fourth pixel unit including a plurality of pixels arranged in parallel with the first pixel unit, the second pixel unit, and the third pixel unit, and a second curve function filter arranged to cover the fourth pixel unit and having a characteristic that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and further includes a fourth line sensor unit that detects measurement light from an object moving relatively to the fourth pixel unit and outputs a fourth detection signal, and the calculation unit acquires a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal, the second detection signal, the third detection signal, and the fourth detection signal."

[0099] The optical information acquisition device of the embodiment may be [8] "the optical information acquisition device described in [7] above, wherein the second curve function filter is a filter made by stacking three monotonic function filters having a characteristic that the transmittance changes monotonically depending on the wavelength in a predetermined wavelength range."

[0100] The optical information acquisition device of the embodiment may be [9] "the optical information acquisition device described in the above [8], which further includes a fifth pixel unit including a plurality of pixels arranged in parallel with the first pixel unit, the second pixel unit, the third pixel unit, and the fourth pixel unit, and a third curve function filter arranged to cover the fifth pixel unit and having a property that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and which detects measurement light from an object moving relatively to the fifth pixel unit and outputs a fifth detection signal, and the calculation unit acquires a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal, the second detection signal, the third detection signal, the fourth detection signal, and the fifth detection signal."

[0101] The optical information acquisition device of the embodiment may be

[10] "the optical information acquisition device described in [9] above, wherein the third curve function filter is a filter formed by stacking four monotonic function filters having a characteristic that the transmittance changes monotonically depending on the wavelength in a predetermined wavelength range."

[0102] The optical information acquisition method of the embodiment may be

[11] "a first optical detection step of detecting measurement light from an object moving relatively to a first pixel unit having a plurality of pixels arranged thereon, and outputting a first detection signal; a second optical detection step of detecting measurement light from an object moving relatively to the second pixel unit, using a second pixel unit having a plurality of pixels arranged thereon and a monotonic function filter, the filter being arranged to cover the second pixel unit and having a characteristic that transmittance changes monotonically according to wavelength in a predetermined wavelength range, and outputting a second detection signal; and a calculation step of acquiring a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal and the second detection signal, wherein there is a predetermined time difference between the detection timing of the measurement light by the first optical detection step and the detection timing of the measurement light by the second optical detection step."

[0103] The optical information acquisition method of the embodiment may be

[12] "the optical information acquisition method described in the above

[11] , further including a third optical detection step of detecting measurement light from an object moving relatively to the third pixel unit using a third pixel unit formed by an array of a plurality of pixels and a first curve function filter arranged to cover the third pixel unit and having a property that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and outputting a third detection signal, wherein in the calculation step, a characteristic value related to the wavelength spectrum of the measurement light is acquired based on at least the first detection signal, the second detection signal, and the third detection signal."

[0104] The optical information acquisition method of the embodiment may be

[13] "the optical information acquisition method described in the above

[12] , further comprising a fourth optical detection step of detecting measurement light from an object moving relatively to the fourth pixel unit using a fourth pixel unit formed by an array of a plurality of pixels and a second curve function filter arranged to cover the fourth pixel unit and having a property that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and outputting a fourth detection signal, wherein in the calculation step, a characteristic value related to the wavelength spectrum of the measurement light is acquired based on at least the first detection signal, the second detection signal, the third detection signal, and the fourth detection signal."

[0105] The optical information acquisition method of the embodiment may be

[14] "the optical information acquisition method described in the above

[13] , further including a fifth optical detection step of detecting measurement light from an object moving relatively to the fifth pixel unit using a fifth pixel unit formed by an array of a plurality of pixels and a third curve function filter arranged to cover the fifth pixel unit and having a property that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and outputting a fifth detection signal, wherein in the calculation step, a characteristic value related to the wavelength spectrum of the measurement light is acquired based on at least the first detection signal, the second detection signal, the third detection signal, the fourth detection signal, and the fifth detection signal."

[0106] 1...measurement system (optical information acquisition device), 10...computer (calculation unit), 22...pixel, 23a, 23b, 23c, 23d, 23e...pixel unit, 25...window unit (plate member), 31...LRG filter (monotone function filter), 33...quadratic function filter (first curve function filter), 35...cubic function filter (second curve function filter), 37...quartic function filter (third curve function filter), 39...neutral attenuation filter, Lb...measurement light, S...object.

Claims

1. An optical information acquisition device comprising: a first line sensor unit having a first pixel unit consisting of an array of multiple pixels, which detects measurement light from an object moving relatively to the first pixel unit and outputs a first detection signal; a second pixel unit having a plurality of pixels arranged in parallel with the first pixel unit, and a monotonic function filter arranged to cover the second pixel unit and having a characteristic that transmittance changes monotonically depending on wavelength in a predetermined wavelength range, which detects measurement light from an object moving relatively to the second pixel unit and outputs a second detection signal; and a calculation unit that acquires characteristic values ​​related to the wavelength spectrum of the measurement light based on at least the first detection signal and the second detection signal, wherein there is a predetermined time difference between the detection timing of the measurement light of the first line sensor unit and the detection timing of the measurement light of the second line sensor unit.

2. The optical information acquisition device according to claim 1, wherein the first line sensor unit is arranged to cover the first pixel unit and further includes a neutral density filter that attenuates the measurement light.

3. An optical information acquisition device as described in claim 1 or 2, wherein the exposure time for one detection of the measurement light in the first line sensor unit is set shorter than the exposure time for one detection of the measurement light in the second line sensor unit.

4. An optical information acquisition device according to any one of claims 1 to 3, further comprising a plate member arranged to cover the second pixel portion and transmitting the measurement light, wherein the monotonic function filter is arranged on a surface of the plate member facing the second pixel portion.

5. An optical information acquisition device according to any one of claims 1 to 4, further comprising: a third pixel unit comprising a plurality of pixels arranged in parallel with the first pixel unit and the second pixel unit; and a first curve function filter arranged to cover the third pixel unit and having a characteristic that transmittance changes in a curved manner depending on wavelength in a predetermined wavelength range; a third line sensor unit that detects measurement light from an object moving relatively to the third pixel unit and outputs a third detection signal; and the calculation unit acquires a characteristic value relating to the wavelength spectrum of the measurement light based on at least the first detection signal, the second detection signal, and the third detection signal.

6. An optical information acquisition device according to claim 5, wherein the first curve function filter is a filter formed by stacking two monotonic function filters each having a characteristic that transmittance changes monotonically depending on wavelength in a predetermined wavelength range.

7. The optical information acquisition device according to claim 5, further comprising: a fourth pixel unit comprising a plurality of pixels arranged in parallel with the first pixel unit, the second pixel unit, and the third pixel unit; and a second curve function filter arranged to cover the fourth pixel unit and having a characteristic that transmittance changes in a curved manner depending on wavelength in a predetermined wavelength range; a fourth line sensor unit that detects measurement light from an object moving relatively to the fourth pixel unit and outputs a fourth detection signal; and the calculation unit acquires a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal, the second detection signal, the third detection signal, and the fourth detection signal.

8. The optical information acquisition device according to claim 7, wherein the second curved function filter is a filter formed by stacking three monotonic function filters each having a characteristic that transmittance changes monotonically depending on wavelength in a predetermined wavelength range.

9. The optical information acquisition device according to claim 7 or 8, further comprising: a fifth pixel unit comprising a plurality of pixels arranged in parallel with the first pixel unit, the second pixel unit, the third pixel unit, and the fourth pixel unit; and a third curve function filter arranged to cover the fifth pixel unit and having a characteristic that transmittance changes in a curved manner depending on wavelength in a predetermined wavelength range; a fifth line sensor unit that detects measurement light from an object moving relatively to the fifth pixel unit and outputs a fifth detection signal; and the calculation unit acquires a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal, the second detection signal, the third detection signal, the fourth detection signal, and the fifth detection signal.

10. An optical information acquisition device according to claim 9, wherein the third curve function filter is a filter formed by stacking four monotonic function filters each having a characteristic that transmittance changes monotonically depending on wavelength in a predetermined wavelength range.

11. A method for acquiring optical information, comprising: a first optical detection step of detecting measurement light from an object moving relatively to a first pixel unit having a plurality of pixels arranged thereon, and outputting a first detection signal; a second optical detection step of detecting measurement light from an object moving relatively to the second pixel unit, using a second pixel unit having a plurality of pixels arranged thereon and a monotonic function filter arranged to cover the second pixel unit, the monotonic function filter having a characteristic that transmittance changes monotonically according to wavelength in a predetermined wavelength range, and outputting a second detection signal; and a calculation step of acquiring a characteristic value related to the wavelength spectrum of the measurement light based on at least the first detection signal and the second detection signal, wherein there is a predetermined time difference between the detection timing of the measurement light by the first optical detection step and the detection timing of the measurement light by the second optical detection step.

12. The optical information acquisition method according to claim 11, further comprising a third optical detection step of detecting measurement light from an object moving relatively to the third pixel unit using a third pixel unit formed by an array of multiple pixels and a first curve function filter arranged to cover the third pixel unit and having a characteristic that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and outputting a third detection signal, wherein in the calculation step, a characteristic value relating to the wavelength spectrum of the measurement light is acquired based on at least the first detection signal, the second detection signal, and the third detection signal.

13. The optical information acquisition method according to claim 12, further comprising a fourth optical detection step that detects measurement light from an object moving relatively to the fourth pixel unit using a fourth pixel unit formed by an array of multiple pixels and a second curve function filter that is arranged to cover the fourth pixel unit and has a characteristic that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and outputs a fourth detection signal, and wherein in the calculation step, a characteristic value related to the wavelength spectrum of the measurement light is acquired based on at least the first detection signal, the second detection signal, the third detection signal, and the fourth detection signal.

14. The optical information acquisition method according to claim 13, further comprising a fifth optical detection step of detecting measurement light from an object moving relatively to the fifth pixel unit using a fifth pixel unit formed by an array of multiple pixels and a third curve function filter arranged to cover the fifth pixel unit and having a characteristic that transmittance changes curvedly depending on wavelength in a predetermined wavelength range, and outputting a fifth detection signal, wherein in the calculation step, a characteristic value related to the wavelength spectrum of the measurement light is acquired based on at least the first detection signal, the second detection signal, the third detection signal, the fourth detection signal, and the fifth detection signal.

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