Imaging device

Abstract

An imaging device (1) comprises, within a housing (10), a first detection substrate (5) that detects reflected light Lr, a second detection substrate (6) that detects transmitted light Lt, and a holding member (12). The first detection substrate (5) includes a first image sensor (51) that receives the reflected light Lr, and a first terminal serving as an output end of reflected-light luminance data. The second detection substrate (6) includes a second image sensor (61) for receiving the transmitted light Lt, and a second terminal serving as an output end of transmitted-light luminance data. The first detection substrate (5) and the second detection substrate (6) are held by the holding member (12) so as to protrude in mutually opposite directions from the holding member (12), the first terminal is positioned at the protruding portion of the first detection substrate (5), and the second terminal is positioned at the protruding portion of the second detection substrate (6).

Description

Imaging device

[0001] The present disclosure relates to an imaging device.

[0002] An example of a conventional imaging device is an imaging unit described in Patent Document 1. The imaging unit in Patent Document 1 includes an inclined dichroic mirror that separates light from a sample by transmitting or reflecting it according to wavelength, a first imaging unit that captures the light transmitted through the inclined dichroic mirror, and a second imaging unit that captures the light reflected by the inclined dichroic mirror. The first imaging unit and the second imaging unit output the imaging results to a control device. The control device corrects the acquired imaging results in consideration of optical characteristics related to changes in transmittance and reflectance with respect to wavelength in the inclined dichroic mirror. The control device analyzes the corrected image to determine whether the sample is good or bad.

[0003] International Publication No. 2021 / 161684

[0004] In the imaging device described above, an optical member that guides incident light, an imaging unit, various boards that perform image generation processing and output processing based on the imaging results of the imaging unit, etc. are arranged inside the housing. Flexible cables such as FFCs (Flexible Flat Cables) and FPCs (Flexible Printed Circuits) are used between the imaging unit and the various boards, but if the cable wiring inside the housing becomes complicated, it is conceivable that the housing will become large.

[0005] The present disclosure provides an imaging device with a compact housing.

[0006] The gist of the present disclosure is as follows.

[0007] [1] A housing includes a first prism having a separation surface that separates incident light into a first light and a second light, a second prism optically coupled to the first prism via the separation surface, a first detection board that detects the first light from the first prism, a second detection board that detects the second light from the second prism, and a holding member that integrally holds the first prism, the second prism, the first detection board, and the second detection board, and the first detection board includes a first image sensor that receives the first light. the second detection board includes a second image sensor that receives the second light and a second terminal that is an output end of a second signal from the second image sensor, the first detection board and the second detection board are held by the holding member so as to protrude in opposite directions from the holding member, and the first terminal is located on the protruding portion of the first detection board and the second terminal is located on the protruding portion of the second detection board.

[0008] In this imaging device, the first prism, the second prism, the first detection board, and the second detection board are held together by a holding member. Furthermore, the first detection board protrudes from the holding member in the opposite direction from the second detection board, with the first terminal and the second terminal located on each protruding portion. This allows the cable connected to the first terminal and the cable connected to the second terminal to be routed symmetrically within the housing. Therefore, in this imaging device, the components within the housing can be compactly arranged, enabling the housing to be made smaller.

[0009] [2] The imaging device according to [1] further includes a first image generation board that generates first image data based on the first signal and a second image generation board that generates second image data based on the second signal, the first image generation board being disposed on a first inner wall of the housing that faces the protruding portion of the first detection board from the holding member, and the second image generation board being disposed on a second inner wall of the housing that faces the protruding portion of the second detection board from the holding member. In this case, the first image generation board faces the protruding portion of the first detection board, and the second image generation board faces the protruding portion of the second detection board, thereby simplifying the routing of the cables connecting them. This allows for further miniaturization of the housing and simplifies the assembly of the device.

[0010] [3] The imaging device according to [2], wherein the opposing direction between the first image generation board and the protruding portion of the first detection board is along the arrangement direction of the first image sensors and the first terminals on the first detection board, and the opposing direction between the second image generation board and the protruding portion of the second detection board is along the arrangement direction of the second image sensors and the second terminals on the second board. In this case, the distance between the first terminals and the first image generation board and the distance between the second terminals and the second image generation board are reduced, thereby further simplifying the routing of cables connecting them.

[0011] [4] The imaging device according to [2], further comprising an image processing board in the housing that combines the first image data and the second image data and outputs the combined image data to the outside, the image processing board being disposed on a third inner wall of the housing that does not face either the protruding portion of the first detection board from the holding member or the protruding portion of the second detection board from the holding member. In this case, by utilizing, among the inner walls of the housing, an inner wall that does not face either the protruding portion of the first detection board or the protruding portion of the second detection board for disposing the image processing board, it is possible to achieve further miniaturization of the housing.

[0012] [5] The imaging device according to any one of [2] to [4], wherein the arrangement positions of the first image sensor and the first terminal on the first detection board are the same as the arrangement positions of the second image sensor and the second terminal on the second detection board, and the first detection board and the second detection board are held by the holding member in a state where one of them is inverted relative to the other in an in-plane direction of the board. In this case, the configuration of the first detection board and the second detection board can be made common, thereby simplifying the device configuration.

[0013] [6] The imaging device according to [5], wherein one of the first image generating board and the second image generating board inverts the orientation of the image in the image data it outputs. In this case, even if the first detection board and the second detection board are inverted in the in-plane direction of the boards, the orientation of the first image data output from the first detection board and the orientation of the second image data output from the second detection board can be aligned. This makes it easy to handle the first image data and the second image data.

[0014] [7] The imaging device according to any one of [1] to [6], wherein the separation surface is constituted by an optical element having a characteristic that the transmittance and reflectance change monotonically in a predetermined wavelength region. In this case, centroid wavelength image data, luminance image data, etc. can be generated from the image data of the transmitted light and the reflected light, and various analyses can be performed using the centroid wavelength image data, luminance image data, etc.

[0015] [8] The imaging device according to any one of [1] to [6], wherein the separation surface is constituted by a beam splitter, and an optical element having a characteristic that transmittance and reflectance change monotonically in a predetermined wavelength region is disposed in either the optical path of the first light or the optical path of the second light. Even with this configuration, centroid wavelength image data, luminance image data, etc. can be generated from image data of the transmitted light and the reflected light, and various analyses can be performed using the centroid wavelength image data, luminance image data, etc.

[0016] According to the present disclosure, the housing of the imaging device can be made smaller.

[0017] 1 is a block diagram showing an imaging system including an imaging device according to an embodiment; FIG. 2 is a diagram showing an example of the appearance of a housing; FIG. 3 is a diagram showing an example of a side view of an imaging device; FIG. 4 is a diagram showing an example of a relationship between incident light and the transmission characteristics of a filter surface; FIG. 5 is a diagram showing an example of a perspective view of an imaging device; FIG. 6 is a diagram showing an example of a rear view of an imaging device; FIG. 7 is a diagram showing another example of a rear view of an imaging device; FIG. 8 is a flowchart showing an example of an imaging method; FIG. 9 is a diagram showing another example of an image dataset; FIG. 10 is a diagram showing another example of an image dataset; FIG. 11 is a diagram showing an example of a side view of an imaging device according to a first modified example; FIG. 12 is a diagram showing an example of a side view of an imaging device according to a second modified example; and FIG. 13 is a diagram showing an example of a side view of an imaging device according to a third modified example.

[0018] Hereinafter, a preferred embodiment of an imaging device according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0019] 1 is a block diagram showing an imaging system 100 including an imaging device 1 according to one embodiment. The imaging system 100 includes the imaging device 1 and an analyzing device 20. The imaging device 1 separates incident light L1 (e.g., observation light) from a sample according to wavelength components, generates image data based on luminance data detected for each wavelength component, and outputs the image data to the analyzing device 20. The analyzing device 20 analyzes the image data output from the imaging device 1 to, for example, determine whether the sample is good or bad.

[0020] The sample may be, for example, a light-emitting element such as an LED, mini-LED, μLED, SLD element, laser element, vertical cavity laser element (VCSEL), or OLED, or may be a light-emitting element that adjusts the emission wavelength using a fluorescent material containing nanodots or the like. When the sample is a light-emitting element, the pass / fail judgment is based on, for example, color mottling information between multiple light-emitting elements. The sample may also be a light-reflective semiconductor wafer or food product made of various materials.

[0021] The imaging device 1 includes a prism unit 2 , a first detection board 5 , a second detection board 6 , a first image generation board 7 , a second image generation board 8 , and an image processing board 9 .

[0022] The prism unit 2 includes a first prism 3, a second prism 4, and a filter surface 2a. Incident light L1 incident on the prism unit 2 is separated by the filter surface 2a into reflected light Lr and transmitted light Lt. The reflected light Lr travels through the first prism 3 and is output from the prism unit 2 to a first detection board 5. The transmitted light Lt travels through the second prism 4 and is output from the prism unit 2 to a second detection board 6.

[0023] The first detection substrate 5 includes a first image sensor 51 that receives the reflected light Lr. The first image sensor 51 detects the reflected light Lr from the first prism 3 at a predetermined frame rate. The first image sensor 51 may be an area sensor in which pixels are arranged two-dimensionally, or a line sensor in which pixels are arranged one-dimensionally. If the first image sensor 51 is an area sensor, the first image sensor 51 may be a CCD image sensor, a CMOS image sensor, or an InGaAs image sensor.

[0024] In the first image sensor 51, charges are accumulated in each pixel by exposure to reflected light Lr. The first image sensor 51 outputs an electrical signal (e.g., a signal indicating a voltage value) corresponding to the amount of accumulated charges. Here, the electrical signal is reflected light luminance data Dr based on the magnitude of the luminance of the reflected light Lr received by the first image sensor 51. The first image sensor 51 generates reflected light luminance data Dr for each frame time corresponding to a predetermined frame rate. The first image sensor 51 outputs the reflected light luminance data Dr for each pixel to a first image generator 71 included in the first image generation board 7.

[0025] The second detection substrate 6 includes a second image sensor 61 that receives the transmitted light Lt. The second image sensor 61 detects the transmitted light Lt from the second prism 4 at a predetermined frame rate. This predetermined frame rate is the same as the frame rate at which the first image sensor 51 detects. The second image sensor 61 may be an area sensor in which pixels are arranged two-dimensionally, or may be a line sensor in which pixels are arranged one-dimensionally. If the second image sensor 61 is an area sensor, the second image sensor 61 may be a CCD image sensor, a CMOS image sensor, or an InGaAs image sensor.

[0026] In the second image sensor 61, charges are accumulated in each pixel by exposure to transmitted light Lt. The second image sensor 61 outputs an electrical signal (e.g., a signal indicating a voltage value) corresponding to the amount of accumulated charges. Here, the electrical signal is transmitted light luminance data Dt based on the magnitude of the luminance of the transmitted light Lt received by the second image sensor 61. The second image sensor 61 generates transmitted light luminance data Dt for each frame time corresponding to a predetermined frame rate. The second image sensor 61 outputs the transmitted light luminance data Dt for each pixel to a second image generator 81 included in the second image generation board 8.

[0027] The timing at which the reflected light luminance data Dr is output by the first image sensor 51 is the same as the timing at which the transmitted light luminance data Dt is output by the second image sensor 61. For example, the first image sensor 51 and the second image sensor 61 may be the same image sensor. In this case, the frame time of the first image sensor 51 may be synchronized with the frame time of the second image sensor 61. When the frame time is composed of an exposure time, a luminance data readout time, and a luminance data transfer time, it is sufficient that at least one of these times is synchronized between the first image sensor 51 and the second image sensor 61. For example, the exposure time may be synchronized between the first image sensor 51 and the second image sensor 61.

[0028] The first image generation board 7 includes a first image generator 71. The first image generator 71 generates first image data based on the reflected light luminance data Dr. The first image sensor 51 and the first image generator 71 are electrically connected via, for example, a flexible flat cable. The first image generator 71 generates reflected light image data Gr from the reflected light luminance data Dr. The reflected light image data Gr is an example of first image data. The first image generator 71 may, for example, generate the reflected light image data Gr by integrating multiple acquired pieces of reflected light luminance data Dr. The first image generator 71 may also generate the reflected light image data Gr by correcting the linearity of the reflected light luminance data Dr. The first image generator 71 outputs the generated reflected light image data Gr to an image processor 91 included in the image processing board 9. The first image generator 71 may be configured using an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), for example.

[0029] The second image generation board 8 includes a second image generator 81. The second image generator 81 generates second image data based on the transmitted light luminance data Dt. The second image sensor 61 and the second image generator 81 are electrically connected via, for example, a flexible flat cable. The second image generator 81 generates transmitted light image data Gt from the transmitted light luminance data Dt. The transmitted light image data Gt is an example of second image data. The second image generator 81 may generate the transmitted light image data Gt by, for example, integrating multiple acquired transmitted light luminance data Dt. The second image generator 81 may also generate the transmitted light image data Gt by correcting the linearity of the transmitted light luminance data Dt. The second image generator 81 outputs the generated transmitted light image data Gt to an image processor 91 included in the image processing board 9. The second image generator 81 may be configured using an FPGA, an ASIC, or the like.

[0030] The first image data or the second image data includes not only the reflected light image data Gr and the transmitted light image data Gt, but also various variations such as luminance image data or centroid wavelength data processed based on the reflected light luminance data Dr and the transmitted light luminance data Dt. The luminance image data and centroid wavelength data will be described later. In the following description, as an example, the first image data will be described as the reflected light image data Gr and the second image data will be described as the transmitted light image data Gt.

[0031] The timing at which the reflected light image data Gr is output by the first image generator 71 is the same as the timing at which the transmitted light image data Gt is output by the second image generator 81. For example, the image processor 91 included in the image processing board 9 may transmit a synchronization signal to the first image generator 71 and the second image generator 81, thereby synchronizing the output timing of the first image generator 71 and the output timing of the second image generator 81.

[0032] The image processor 91 generates an image data set Gs by combining image data based on the first image data and the second image data. The image processor 91, for example, combines reflected light image data Gr and transmitted light image data Gt and outputs the combined image data Gs to the outside. The image processor 91 generates an image data set Gs by combining image data based on the reflected light image data Gr and transmitted light image data Gt. The image data set Gs will be described later. The image processor 91 then outputs the image data set Gs to an analysis device 20 provided outside the imaging device 1. The image processor 91 may be configured with an FPGA, an ASIC, or the like. The image processor 91 communicates with the first image generator 71 and the second image generator 81, for example, via serial transmission or parallel transmission.

[0033] The above-described first image generator 71, second image generator 81, and image processor 91 constitute a processing unit P in the imaging device 1. That is, the processing unit P generates reflected light image data Gr and transmitted light image data Gt based on the reflected light luminance data Dr and transmitted light luminance data Dt output at the same time from the first image sensor 51 and the second image sensor 61. The processing unit P then generates an image data set Gs by combining image data based on the reflected light image data Gr and transmitted light image data Gt.

[0034] The first detection substrate 5 may further include a Peltier element (not shown). The Peltier element is a thermoelectric cooling element that utilizes the Peltier effect. The Peltier element cools the first image sensor 51. The first image generation substrate 7 may further include a drive element for driving the Peltier element. The drive element is, for example, a current source. When the drive element passes a current through the Peltier element, the Peltier element cools the first image sensor 51 to a temperature that corresponds to the magnitude of the current. Similarly, the second detection substrate 6 may further include a Peltier element for cooling the second image sensor 61, and the second image generation substrate 8 may further include a drive element for driving the Peltier element.

[0035] The imaging device 1 may further include a motor driver (not shown). The first detection board 5 and the second detection board 6 may each be placed on a support table (not shown) that is movable in two or three dimensions, for example. The support table may be motor-driven and controlled by the motor driver. Furthermore, the position of the support table may be controlled by, for example, the first image generator 71 and the second image generator 81. When changing the positions of the first detection board 5 and the second detection board 6, the first image generator 71 and the second image generator 81 may drive the motor driver and control the support table so that the first detection board 5 and the second detection board 6 reach desired positions.

[0036] [Specific Structure of Imaging Device] Next, a specific structure of the imaging device 1 will be described. The imaging device 1 further includes a housing 10 that houses the prism unit 2, the first detection board 5, the second detection board 6, the first image generation board 7, the second image generation board 8, and the image processing board 9. FIG. 2 is a diagram showing an example of the appearance of the housing 10. The housing 10 is, for example, a hexahedral box-like cubic shape. The housing 10 is made of, for example, metal, and protects and shields the functional components housed therein from light.

[0037] A mount 11 is provided on one side of the housing 10. The mount 11 is a connection portion for attaching a lens to the housing 10. By attaching the lens to the housing 10 via the mount 11, the lens and the prism unit 2 are optically connected. The lens is arranged, for example, so that incident light L1 from the sample is focused onto each of the first image sensor 51 and the second image sensor 61. The mount 11 may be, for example, a screw mount such as an M52 mount or a C mount, or a bayonet mount such as an F mount.

[0038] A connector C1 for electrically connecting the analysis device 20 and the imaging device 1 may be formed on another side surface of the housing 10. The imaging device 1 and the analysis device 20 are connected by, for example, a Camera Link interface, and the imaging device 1 performs high-speed data transfer of image data to the analysis device 20 via this interface. The connector C1 may be, for example, an SDR (Shrunk Delta Ribbon connector) connector or an MDR (Mini Delta Ribbon) connector.

[0039] Next, the configuration of the prism unit 2 will be described. FIG. 3 is a diagram schematically illustrating an example of a side view of the imaging device 1. The first prism 3 has a separation surface 3a that separates the incident light L1 incident from the mount 11. In this embodiment, the separation surface 3a is formed with a filter surface 2a having characteristics in which the transmittance and reflectance change monotonically over a predetermined wavelength range. Here, the filter surface 2a is formed with a light dividing element (beam splitter) called a linear reflectance gradient (LRG) dichroic mirror. The inclined dichroic mirror is formed, for example, with a dielectric multilayer film, and transmits and reflects the incident light L1 according to its wavelength, thereby dividing the incident light L1 into transmitted light Lt and reflected light Lr.

[0040] 4 is a diagram illustrating an example of the relationship between incident light L1 and the transmission characteristics of the filter surface 2a. For example, when a sample includes μLEDs and the incident light L1 has a center wavelength λ 2 different from the center wavelength λ 2 , １ ~λ ３ As shown in Fig. 4, the wavelength range in which the transmittance of the filter surface 2a changes linearly is set based on the wavelength range of the incident light L1. In the example of Fig. 4, the transmittance of the filter surface 2a changes linearly at a center wavelength λ １ In the wavelength region smaller than λ, it is close to 0%. １ ~λ ３ The transmittance of the filter surface 2a increases at a constant rate in the wavelength region including the center wavelength λ ３ In the wavelength range greater than 100%, the transmittance approaches 100%. The transmittance and reflectance of the filter surface 2a are negatively correlated, so that as one increases, the other decreases. The wavelength range in which the transmittance of the filter surface 2a increases at a constant rate is, for example, 400 nm to 800 nm.

[0041] The first prism 3 further has an input surface 3b and an output surface 3c. The input surface 3b faces the inner wall of the side of the housing 10 on which the mount 11 is provided. The first prism 3 is optically connected to the first image sensor 51 included in the first detection board 5. The reflected light Lr reflected at the separation surface 3a is further reflected at the input surface 3b. The input surface 3b serves as an input surface for the incident light L1, but serves as a total reflection surface for the reflected light Lr reflected at the separation surface 3a. The reflected light Lr then travels within the first prism 3, is output from the output surface 3c, and enters the first image sensor 51.

[0042] The second prism 4 is optically coupled to the first prism 3 via the separation surface 3a. The second prism 4 has an input surface 4a and an output surface 4b. The input surface 4a is bonded to the separation surface 3a without any gap. This optically couples the first prism 3 and the second prism 4. The second prism 4 is optically connected to a second image sensor 61 included in the second detection substrate 6. The transmitted light Lt that has passed through the separation surface 3a travels within the second prism 4, is output from the output surface 4b, and input to the second image sensor 61.

[0043] Next, the internal structure of the housing 10 will be described in more detail with reference to Figures 3, 5, and 6. Figure 5 is a diagram schematically showing an example of a perspective view of the imaging device 1, and Figure 6 is a diagram schematically showing an example of a rear view of the imaging device 1.

[0044] 3, the first image sensor 51 is mounted on the surface of the first detection substrate 5. The first image sensor 51 is disposed so as to face the first prism 3. The first image sensor 51 may be disposed with a space therebetween, for example, by a spacer, or may be disposed so as to be in direct contact with the output surface 3c of the first prism 3. The Peltier element may be mounted on the back surface of the first detection substrate 5 opposite the surface on which the first image sensor 51 is mounted. In addition, a heat sink (not shown) may be connected to the Peltier element to dissipate heat generated by the first image sensor 51.

[0045] The second image sensor 61 is mounted on the surface of the second detection substrate 6. The second image sensor 61 is disposed so as to face the second prism 4. The second image sensor 61 may be disposed with a space between it and the output surface 4b of the second prism 4, for example, by a spacer, or may be disposed so as to be in direct contact with the output surface 4b. As with the first detection substrate 5, a Peltier element (not shown) and a heat sink (not shown) may be mounted on the back surface of the second detection substrate 6.

[0046] The imaging device 1 further includes a holding member 12 within the housing 10. The holding member 12 integrally holds the first prism 3, the second prism 4, the first detection board 5, and the second detection board 6. As shown in FIG. 5 , the holding member 12 may include a pair of legs 121 and 122. The pair of legs 121 and 122 are arranged to sandwich the first prism 3 and the second prism 4. Ends of the pair of legs 121 and 122 on the side where the incident light L1 is incident are coupled to the mount 11. A heat sink is fixed to the end of the pair of legs 121 and 122 opposite the end coupled to the mount 11 via a spacer that passes through a hole in the second detection board 6. A Peltier element is sandwiched between the heat sink and the second detection board 6. The upper surfaces 121 a and 122 a of the pair of legs 121 and 122 are notched in a V-shape in side view. A heat sink is fixed to the inclined portion formed by this shape via a spacer that passes through a hole in the first detection board 5. A Peltier element is sandwiched between this heat sink and the first detection board 5.

[0047] The first detection board 5 further includes a first terminal 53. The first terminal 53 is an output terminal for reflected light luminance data Dr from the first image sensor 51. The second detection board 6 further includes a second terminal 63. The second terminal 63 is an output terminal for transmitted light luminance data Dt from the second image sensor 61. The first terminal 53 and the second terminal 63 are, for example, FFC connectors that mate with flexible flat cables.

[0048] The first detection board 5 and the second detection board 6 are held by the prisms (the first prism 3 and the second prism 4) via image sensors (the first image sensor 51 and the second image sensor 61) so as to protrude in opposite directions from the holding member 12. As shown in FIGS. 5 and 6 , the first detection board 5 includes a protruding portion 54 that protrudes beyond the leg portions 121 of the holding member 12 on the side opposite the first prism 3. The second detection board 6 includes a protruding portion 64 that protrudes beyond the leg portions 122 of the holding member 12 on the side opposite the second prism 4. The protruding portions 54 and 64 are located in opposite directions in a direction perpendicular to the traveling direction of the incident light L1. The first terminal 53 is located on the protruding portion 54. The second terminal 63 is located on the protruding portion 64.

[0049] In this embodiment, the arrangement positions of the first image sensor 51 and the first terminal 53 on the first detection board 5 are the same as the arrangement positions of the second image sensor 61 and the second terminal 63 on the second detection board 6. The first detection board 5 has a shape whose longitudinal direction is a direction perpendicular to the traveling direction of the incident light L1. The arrangement direction of the first image sensor 51 and the first terminal 53 on the first detection board 5 coincides with the longitudinal direction of the first detection board 5. The second detection board 6 has a shape whose longitudinal direction is a direction parallel to the longitudinal direction of the first detection board 5. The arrangement direction of the second image sensor 61 and the second terminal 63 on the second detection board 6 coincides with the longitudinal direction of the second detection board 6.

[0050] The first detection board 5 and the second detection board 6 are held by the holding member 12 in a state in which one of them is inverted relative to the other in the in-plane direction of the board. In the example of Figures 5 and 6, the first detection board 5 is arranged in a state rotated 180 degrees about the rotation axis relative to the second detection board 6, when the direction perpendicular to the board is taken as the rotation axis.

[0051] As shown in Fig. 5, when an imaginary line A1 is drawn from the mount 11 along the upper surfaces 121a, 122a of the holding member 12 to the end of the holding member 12 connected to the second detection board 6, the first image sensor 51 and the second image sensor 61 are both located on the imaginary line A1. As shown in Fig. 6, for example, when the upper surfaces 121a, 122a of the legs 121, 122 of the holding member 12 are viewed from above, the first image sensor 51 and the second image sensor 61 are located in a straight line on the imaginary line A1. As a result, the first terminal 53 and the second terminal 63 are arranged symmetrically with respect to the imaginary line A1.

[0052] As shown in FIG. 3 , the imaging device 1 may further include a cut filter 13 and a depolarizer 14. In the example of FIG. 3 , the cut filter 13 and the depolarizer 14 are disposed before the first prism 3. The incident light L1 passes through the cut filter 13 and the depolarizer 14 before reaching the separation surface 3a. The cut filter 13 is, for example, a bandpass filter. The cut filter 13 may pass light within a wavelength range in which the transmittance of the filter surface 2a on the separation surface 3a increases at a constant rate, and block light within other wavelength ranges. The depolarizer 14 converts the incident light L1 into unpolarized light when the incident light L1 is p-polarized, s-polarized, or elliptically polarized. The transmittance of the incident light L1 on the separation surface 3a may vary between p-polarized and s-polarized light. The depolarizer 14 can eliminate the polarization dependency of the incident light L1.

[0053] Next, the internal structure of the housing 10 of the imaging device 1, including the first image generation board 7, the second image generation board 8, and the image processing board 9, will be described. FIG. 7 is a diagram schematically illustrating another example of a rear view of the imaging device 1. FIG. 7 shows the state in which the rear panel of the housing 10 has been removed to reveal the interior. The housing 10 has inner walls 10a and 10b that face each other. As shown in FIG. 7, the first image generation board 7 is disposed on the inner wall 10a. The second image generation board 8 is disposed on the inner wall 10b. The in-plane direction of the first image generation board 7 is parallel to the inner wall 10a, and the in-plane direction of the second image generation board 8 is parallel to the inner wall 10b. In other words, the first image generation board 7 and the second image generation board 8 are disposed so as to face each other.

[0054] The first image generating board 7 faces the protruding portion 54 of the first detection board 5 that protrudes from the holding member 12. The second image generating board 8 faces the protruding portion 64 of the second detection board 6 that protrudes from the holding member 12. The opposing direction of the first image generating board 7 and the protruding portion 54 of the first detection board 5 is along the arrangement direction of the first image sensors 51 and the first terminals 53 on the first detection board 5. In the example of FIG. 7 , the longitudinal direction of the first detection board 5 and the opposing direction of the first image generating board 7 and the protruding portion 54 of the first detection board 5 coincide with each other. The first image generating board 7 is located on an extension of the longitudinal direction of the first detection board 5. The opposing direction of the second image generating board 8 and the protruding portion 64 of the second detection board 6 is along the arrangement direction of the second image sensors 61 and the second terminals 63 on the second detection board 6. 7, the longitudinal direction of the second detection board 6 coincides with the opposing direction of the second image generation board 8 and the protruding portion 64 of the second detection board 6. The second image generation board 8 is located on an extension of the longitudinal direction of the second detection board 6.

[0055] The first image generation board 7 further includes a third terminal 73. The third terminal 73 is an input terminal for the reflected light luminance data Dr output from the first terminal 53. The second image generation board 8 further includes a fourth terminal 83. The fourth terminal 83 is an input terminal for the transmitted light luminance data Dt output from the second terminal 63. The third terminal 73 and the fourth terminal 83 are, for example, FFC connectors that mate with flexible flat cables (FFC). The third terminal 73 and the first terminal 53 are connected by a flexible flat cable FC1. The flexible flat cable FC1 is wired from the first terminal 53 perpendicular to the board, bent parallel to the board in the direction opposite to the third terminal 73, and then folded back toward the third terminal 73 to connect to the third terminal 73. The fourth terminal 83 and the second terminal 63 are connected by a flexible flat cable FC2. The flexible flat cable FC2 is wired from the second terminal 63 perpendicular to the substrate, bent parallel to the substrate in the direction opposite to the fourth terminal 83, and then folded back toward the fourth terminal 83 to be connected to the fourth terminal 83. Note that an FPC (Flexible Printed Circuits) may be used instead of the flexible flat cable.

[0056] The housing 10 further includes an inner wall 10c connecting the inner wall 10a and the inner wall 10b. In this embodiment, the housing 10 has a cubic shape, and the inner wall 10c is perpendicular to the inner walls 10a and 10b. The image processing board 9 is disposed on the inner wall 10c. As a result, the image processing board 9 is disposed in the housing 10 so as not to face either the protruding portion 54 of the first detection board 5 from the holding member 12 or the protruding portion 64 of the second detection board 6 from the holding member 12, but is perpendicular to both the opposing direction of the first image generation board 7 and the protruding portion 54 and the opposing direction of the second image generation board 8 and the protruding portion 64.

[0057] [Imaging Method] Next, a description will be given of an imaging method using the imaging device 1. Fig. 8 is a flowchart showing an example of an imaging method (hereinafter, method MT1). In method MT1, steps ST1 to ST4 can be repeatedly performed in this order.

[0058] First, the first image sensor 51 detects the luminance of the reflected light Lr to generate reflected light luminance data Dr, and the second image sensor 61 detects the luminance of the transmitted light Lt to generate transmitted light luminance data Dt (step ST1: luminance data generation step). In step ST1, the first image sensor 51 and the second image sensor 61 output the reflected light luminance data Dr and the transmitted light luminance data Dt at the same time.

[0059] Next, the first image generator 71 generates reflected light image data Gr by combining the reflected light luminance data Dr for each predetermined wavelength region, and the second image generator 81 generates transmitted light image data Gt by combining the transmitted light luminance data Dt for each predetermined wavelength region (step ST2: image data generation step). In step ST2, the first image generator 71 and the second image generator 81 output the reflected light image data Gr and the transmitted light image data Gt at the same time.

[0060] In step ST2, one of the first image generator 71 and the second image generator 81 may invert the orientation of the image in the image data to be output. As described above, the first detection board 5 and the second detection board 6 are held by the holding member 12 with one of them inverted relative to the other in the in-plane direction of the board. Therefore, the orientation of the reflected light image data Gr output from the first image generator 71 and the orientation of the transmitted light image data Gt output from the second image generator 81 may be inverted. In this case, by having one of the first image generator 71 and the second image generator 81 invert the orientation of the image in the image data to be output, the reflected light image data Gr and the transmitted light image data Gt can be output in the same orientation.

[0061] The image orientation inversion in the image data as described above may be performed already when reading out the luminance data from the first image sensor 51 and the second image sensor 61. For example, if the first image sensor 51 and the second image sensor 61 are rolling shutter type, the order in which luminance data is read out from one image sensor may be reversed from the order in which luminance data is read out from the other image sensor. For example, when reading out pixel rows, one image sensor may read out rows one by one from the first row to the last row, while the other image sensor may read out rows one by one from the last row to the first row. The first image sensor 51 and the second image sensor 61 may be global shutter type.

[0062] Next, the image processor 91 generates an image data set Gs (step ST3: image data set generation step). As described above, the first image data or the second image data includes not only the reflected light image data Gr and the transmitted light image data Gt, but also various variations such as luminance image data or centroid wavelength data processed based on the reflected light luminance data Dr and the transmitted light luminance data Dt. Here, the luminance image data or centroid wavelength data is referred to as calculated image data. The image processor 91 generates an image data set Gs consisting of at least two pieces of image data by combining one each of the reflected light image data Gr, the transmitted light image data Gt, and the calculated image data.

[0063] The image processor 91 may generate luminance image data based on the sum of the reflected light luminance data Dr and the transmitted light luminance data Dt as the calculated image data. The luminance image data is data indicating the total amount of light, which is the sum of the luminance of the transmitted light Lt and the luminance of the reflected light Lr. The luminance image data may be generated as first image data or second image data. As shown in FIG. 4 , the pixel value of each pixel included in the luminance image data is expressed as T+R, where R is the count value of the luminance of the reflected light Lr received by each pixel of the first image sensor 51 and T is the count value of the luminance of the transmitted light Lt received by each pixel of the second image sensor 61.

[0064] The image processor 91 may generate, as the calculated image data, centroid wavelength image data that takes relative values ​​for each wavelength region in the reflected light luminance data Dr and the transmitted light luminance data Dt. The centroid wavelength image data is data that indicates the relative values ​​between the luminance of the transmitted light Lt and the luminance of the reflected light Lr. The centroid wavelength image data may be generated as first image data or second image data. As shown in FIG. 4 , the pixel value of each pixel included in the centroid wavelength image data is expressed as (T−R) / (2×(T+R)), where R is the count value of the luminance of the reflected light Lr received by each pixel of the first image sensor 51 and T is the count value of the luminance of the transmitted light Lt received by each pixel of the second image sensor 61.

[0065] The image processor 91 may generate, as the calculated image data, differential image data that is the difference between the reflected light luminance data Dr and the transmitted light luminance data Dt. Alternatively, the image processor 91 may generate, as the calculated image data, data that is easy to use in the analysis device 20. For example, the image processor 91 may perform filter processing on the reflected light image data Gr and the transmitted light image data Gt.

[0066] The image processor 91 generates the image data set Gs by combining any of the image data described above. For example, the image processor 91 generates the image data set Gs by combining reflected light image data Gr generated from reflected light luminance data Dr and transmitted light image data Gt generated from transmitted light luminance data Dt. For example, the image processor 91 generates the image data set Gs by combining luminance image data and centroid wavelength image data. The image data set Gs does not need to consist of two pieces of image data; the image processor 91 may also generate the image data set Gs by combining three or more images.

[0067] The image processor 91 generates an image data set Gs by arranging a combination of a plurality of image data, including reflected light image data Gr, transmitted light image data Gt, luminance image data, and centroid wavelength image data, in a predetermined direction. In the following description, an example will be described in which the image processor 91 generates the image data set Gs by combining the reflected light image data Gr and transmitted light image data Gt.

[0068] 9 to 11 are diagrams showing an example of the image data set Gs. The predetermined direction in which the image processor 91 arranges the reflected light image data Gr and the transmitted light image data Gt will be described using a three-dimensional coordinate system as an example. In the three-dimensional coordinate system shown in FIGS. 9 to 11, the direction in which the pixels of the image data are arranged horizontally is defined as the X direction, the direction in which the pixels of the image data are arranged vertically is defined as the Z direction, and the direction perpendicular to the X and Z directions is defined as the Y direction.

[0069] As shown in FIG. 9 , the image processor 91 may arrange the reflected light image data Gr and the transmitted light image data Gt in the X direction. As shown in FIG. 10 , the image processor 91 may arrange the reflected light image data Gr and the transmitted light image data Gt in the Z direction. As shown in FIG. 11 , the image processor 91 may arrange the reflected light image data Gr and the transmitted light image data Gt in the Y direction. In the example of FIG. 11 , the image processor 91 arranges the reflected light image data Gr and the transmitted light image data Gt so that their image planes overlap. In addition to the above example, the image processor 91 may arrange the reflected light image data Gr and the transmitted light image data Gt in any manner in the three-dimensional coordinate system. For example, the image processor 91 may arrange the reflected light image data Gr and the transmitted light image data Gt diagonally on a plane defined by the X and Z directions.

[0070] The image processor 91 generates the image data set Gs including identification information R for identifying boundaries of the combined image data. As shown in Figures 9 and 10, the image processor 91 may embed a string of dummy pixels with no pixel values ​​as the identification information R between the reflected light image data Gr and the transmitted light image data Gt in the X or Z direction. Alternatively, as shown in Figure 11, the image processor 91 may embed a dummy image as the identification information R between the reflected light image data Gr and the transmitted light image data Gt in the Y direction. Alternatively, the image processor 91 may generate data indicating image alignment information (for example, in the case of 4-bit serial data, "0001" is used when the image data are aligned in the X direction) as the identification information R along with the image data set Gs.

[0071] Finally, the image processor 91 outputs the image data set Gs to the analysis device 20 (step ST4: image data set output step). Since the timing of the image data is maintained uniform within the image data set Gs, the analysis device 20 can analyze the image data without adjusting the timing between the image data, for example.

[0072] [Operation and Effect] In the imaging device 1 according to this embodiment, the first prism 3, the second prism 4, the first detection board 5, and the second detection board 6 are held together by the holding member 12. Furthermore, the first detection board 5 protrudes from the holding member 12 in the opposite direction to the second detection board 6, and the first terminal 53 and the second terminal 63 are located on the respective protruding portions. This allows the cable connected to the first terminal 53 and the cable connected to the second terminal 63 to be wired symmetrically within the housing 10. Therefore, in this imaging device 1, the components within the housing 10 can be compactly arranged, enabling the housing 10 to be made smaller.

[0073] The imaging device 1 according to this embodiment includes a first image generating board 7 that generates reflected light image data Gr (first image data) based on reflected light luminance data Dr (first signal) and a second image generating board 8 that generates transmitted light image data Gt (second image data) based on transmitted light luminance data Dt (second signal) within a housing 10. The first image generating board 7 is disposed on an inner wall 10a (first inner wall) of the housing 10 that faces a protruding portion 54 of the first detection board 5 that protrudes from the holding member 12, and the second image generating board 8 is disposed on an inner wall 10b (second inner wall) of the housing 10 that faces a protruding portion 64 of the second detection board 6 that protrudes from the holding member 12. In this case, the first image generating board 7 and the protruding portion 54 of the first detection board 5 face each other, and the second image generating board 8 faces the protruding portion 64 of the second detection board 6, thereby simplifying the routing of the cables connecting them. This allows for further miniaturization of the housing 10. In addition, the device can be easily assembled.

[0074] In the imaging device 1 according to this embodiment, the opposing direction between the first image generating board 7 and the protruding portion 54 of the first detection board 5 is along the arrangement direction of the first image sensors 51 and the first terminals 53 on the first detection board 5, and the opposing direction between the second image generating board 8 and the protruding portion 64 of the second detection board 6 is along the arrangement direction of the second image sensors 61 and the second terminals 63 on the second detection board 6. In this case, the distance between the first terminals 53 and the first image generating board 7 and the distance between the second terminals 63 and the second image generating board 8 are reduced, which further simplifies the routing of the cables connecting them.

[0075] In the imaging device 1 according to this embodiment, the housing 10 includes an image processing board 9 that combines reflected light image data Gr and transmitted light image data Gt and outputs the combined image data to the outside, and the image processing board 9 is disposed on an inner wall 10c (third inner wall) of the housing 10 that does not face either the protruding portion 54 of the first detection board 5 from the holding member 12 or the protruding portion 64 of the second detection board 6 from the holding member 12. In this case, by utilizing, among the inner walls within the housing 10, an inner wall that does not face either the protruding portion 54 of the first detection board 5 or the protruding portion 64 of the second detection board 6 for disposing the image processing board 9, the housing 10 can be further reduced in size.

[0076] In this embodiment, the positions of the first image sensor 51 and the first terminals 53 on the first detection board 5 are the same as the positions of the second image sensor 61 and the second terminals 63 on the second detection board 6, and the first detection board 5 and the second detection board 6 are held by the holding member 12 in a state where one of them is inverted relative to the other in the in-plane direction of the board. In this case, the first detection board 5 and the second detection board 6 can have a common configuration, which simplifies the device configuration.

[0077] In the imaging device 1 according to this embodiment, one of the first image generating board 7 and the second image generating board 8 inverts the orientation of the image in the image data it outputs. In this case, even if the first detection board 5 and the second detection board 6 are inverted in the in-plane direction of the boards, the orientation of the reflected light image data Gr output from the first detection board 5 and the orientation of the transmitted light image data Gt output from the second detection board 6 can be aligned. This makes it possible to easily handle the reflected light image data Gr and the transmitted light image data Gt.

[0078] In this embodiment, the separation surface 3 a is configured by an optical element having a characteristic in which the transmittance and reflectance change monotonically in a predetermined wavelength range. In this case, centroid wavelength image data, luminance image data, etc. can be generated from the image data of the transmitted light Lt and the reflected light Lr, respectively, and various analyses can be performed using the centroid wavelength image data, luminance image data, etc.

[0079] [Modifications] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments.

[0080] Instead of the separation surface 3a, the filter surface 2a may be formed on any of the output surface 3c of the first prism 3, the input surface 3b of the first prism 3, and the output surface 4b of the second prism 4. In this case, the separation surface 3a may be formed by an optical element without wavelength selectivity. For example, the separation surface 3a may be formed by a beam splitter that separates the incident light L1 at a specific intensity ratio regardless of wavelength. The intensity ratio may be 1:1 or any other ratio. In the following description, a portion of the incident light L1 reflected by the separation surface 3a is referred to as the first incident light L11 (first light), and a portion of the incident light L1 transmitted through the separation surface 3a is referred to as the second incident light L12 (second light). An optical element (filter surface 2a) having a characteristic that its transmittance and reflectance change monotonically in a predetermined wavelength range is disposed in either the optical path of the first incident light L11 or the optical path of the second incident light L12.

[0081] [First Modification] FIG. 12 is a diagram showing an example of a side view of an imaging device 1A according to a first modification. In the imaging device 1A, a filter surface 2a is formed on the output surface 3c of the first prism 3. First, incident light L1 is separated into first incident light L11 and second incident light L12 at the separation surface 3a. The first incident light L11 is reflected at the input surface 3b of the first prism 3 and then split into transmitted light Lt and reflected light Lr (not shown) at the output surface 3c. Of the split light, the first image sensor 51 receives only the transmitted light Lt. Meanwhile, the second incident light L12 travels through the second prism 4 and is input to the second image sensor 61. The first image sensor 51 outputs transmitted light luminance data Dt based on the luminance of the transmitted light Lt to the first image generator 71.

[0082] The second image sensor 61 outputs luminance data based on the magnitude of the luminance of the second incident light L12 to the second image generator 81. The first image generator 71 generates transmitted light image data Gt based on the transmitted light luminance data Dt. The second image generator 81 generates image data based on the luminance data of the second incident light L12. Here, the reflected light Lr split at the output surface 3c is represented by the difference between the second incident light L12 and the transmitted light Lt. In other words, the image processor 91 may generate the reflected light image data Gr by calculating the difference between the image data of the second incident light L12 and the transmitted light image data Gt before generating the image data set Gs.

[0083] [Second Modification] FIG. 13 is a diagram showing an example of a side view of an imaging device 1B according to a second modification. In the imaging device 1B, a filter surface 2a is formed on the input surface 3b of the first prism 3. First, the incident light L1 is separated into a first incident light L11 and a second incident light L12 at the separation surface 3a. The first incident light L11 is split into a transmitted light Lt (not shown) and a reflected light Lr at the input surface 3b of the first prism 3. Of the split light, the first image sensor 51 receives only the reflected light Lr. Meanwhile, the second incident light L12 travels through the second prism 4 and is input to the second image sensor 61. The first image sensor 51 outputs reflected light luminance data Dr based on the luminance of the reflected light Lr to the first image generator 71.

[0084] The second image sensor 61 outputs luminance data based on the magnitude of the luminance of the second incident light L12 to the second image generator 81. The first image generator 71 generates reflected light image data Gr based on the reflected light luminance data Dr. The second image generator 81 generates image data based on the luminance data of the second incident light L12. Here, the transmitted light Lt split at the input surface 3b is represented by the difference between the second incident light L12 and the reflected light Lr. In other words, the image processor 91 may generate the transmitted light image data Gt by calculating the difference between the image data of the second incident light L12 and the reflected light image data Gr before generating the image data set Gs.

[0085] [Third Modification] Figure 14 is a diagram showing an example of a side view of an imaging device 1C according to a third modification. In the imaging device 1C, a filter surface 2a is formed on the output surface 4b of the second prism 4. First, the incident light L1 is separated into a first incident light L11 and a second incident light L12 at the separation surface 3a. The second incident light L12 is split into a transmitted light Lt and a reflected light Lr (not shown) at the output surface 4b of the second prism 4. Of the split light, the second image sensor 61 receives only the transmitted light Lt. Meanwhile, the first incident light L11 travels through the first prism 3 and enters the first image sensor 51.

[0086] The second image sensor 61 outputs transmitted light luminance data Dt based on the magnitude of the luminance of the transmitted light Lt to the second image generator 81. The first image sensor 51 outputs luminance data based on the magnitude of the luminance of the first incident light L11 to the first image generator 71. The second image generator 81 generates transmitted light image data Gt based on the transmitted light luminance data Dt. The first image generator 71 generates image data based on the luminance data of the first incident light L11. Here, the reflected light Lr split at the output surface 4b is represented by the difference between the first incident light L11 and the transmitted light Lt. In other words, the image processor 91 may generate the reflected light image data Gr by calculating the difference between the image data of the first incident light L11 and the transmitted light image data Gt before generating the image data set Gs.

[0087] As described in the first to third modified examples, the separation surface 3 a may be configured by a beam splitter, and an optical element having a characteristic in which the transmittance and reflectance change monotonically in a predetermined wavelength region may be disposed in either the optical path of the first incident light L11 or the optical path of the second incident light L12. Even with this configuration, centroid wavelength image data, luminance image data, etc. can be generated from the image data of the transmitted light Lt and the reflected light Lr, and various analyses can be performed using the centroid wavelength image data, luminance image data, etc.

[0088] 1, 1A, 1B, 1C...imaging device, 3...first prism, 4...second prism, 3a...separation surface, 5...first detection board, 6...second detection board, 7...first image generation board, 8...second image generation board, 9...image processing board, 10...housing, 10a...inner wall (first inner wall), 10b...inner wall (second inner wall), 10c...inner wall (third inner wall), 12...holding member, 51...first image sensor, 61...second image sensor, 53...first terminal, 63...second terminal, 54...protruding portion of first detection board, 64...protruding portion of second detection board, L1...incident light, Lr...reflected light (first light), Lt...transmitted light (second light).

Claims

1. A housing includes a first prism having a separation surface that separates incident light into a first light and a second light, a second prism optically coupled to the first prism via the separation surface, a first detection board that detects the first light from the first prism, a second detection board that detects the second light from the second prism, and a holding member that holds the first prism, the second prism, the first detection board, and the second detection board together, wherein the first detection board includes a first image sensor that receives the first light and a first terminal that serves as an output end for a first signal from the first image sensor, and the second detection board includes a second image sensor that receives the second light and a second terminal that serves as an output end for a second signal from the second image sensor, and the first detection board and the second detection board are held by the holding member so as to protrude in opposite directions from the holding member, An imaging device, wherein a first terminal is located on a protruding portion of the first detection substrate, and a second terminal is located on a protruding portion of the second detection substrate.

2. An imaging device as described in claim 1, comprising within the housing a first image generation board that generates first image data based on the first signal, and a second image generation board that generates second image data based on the second signal, wherein the first image generation board is arranged on a first inner wall of the housing that faces the protruding portion of the first detection board from the holding member, and the second image generation board is arranged on a second inner wall of the housing that faces the protruding portion of the second detection board from the holding member.

3. An imaging device as described in claim 2, wherein the opposing direction between the first image generating board and the protruding portion of the first detection board is along the arrangement direction of the first image sensors and the first terminals on the first detection board, and the opposing direction between the second image generating board and the protruding portion of the second detection board is along the arrangement direction of the second image sensors and the second terminals on the second detection board.

4. An imaging device as described in claim 2, further comprising an image processing board within the housing that combines the first image data and the second image data and outputs the combined image data to the outside, the image processing board being arranged on a third inner wall of the housing that does not face either the protruding portion of the first detection board from the holding member or the protruding portion of the second detection board from the holding member.

5. An imaging device according to any one of claims 2 to 4, wherein the positions of the first image sensor and the first terminal on the first detection board are the same as the positions of the second image sensor and the second terminal on the second detection board, and the first detection board and the second detection board are held by the holding member in a state where one of them is inverted relative to the other in the in-plane direction of the board.

6. The imaging device according to claim 5, wherein one of the first image generation board and the second image generation board inverts the orientation of the image in the image data it outputs.

7. An imaging device according to any one of claims 1 to 6, wherein the separation surface is constituted by an optical element having a characteristic in which the transmittance and reflectance change monotonically in a predetermined wavelength region.

8. An imaging device according to any one of claims 1 to 6, wherein the separation surface is constituted by a beam splitter, and an optical element having a characteristic that transmittance and reflectance change monotonically in a predetermined wavelength region is disposed in either the optical path of the first light or the optical path of the second light.

Images