Spectral chip

Abstract

The utility model relates to a spectrum chip. The spectrum chip comprises a light sensing area, the light sensing area is composed of a photoelectric detection layer and a light modulation layer located above the photoelectric detection layer, the light modulation layer comprises eight light filtering units formed by eight light filtering materials, and the eight light filtering materials and a light filtering unit without a light filtering material are arranged in a 3 * 3 array. Therefore, the predetermined filtering unit has signals at the full wavelength, and sufficient signals can be provided in a dark light environment or a monochromatic light environment, so that the imaging quality is ensured.

Description

Technical Field

[0001] The present application relates to the field of spectral technology, and more specifically, to a spectral chip. Background Art

[0002] When light interacts with matter, such as absorption, scattering, fluorescence, Raman, etc., a specific spectrum will be produced, and the spectrum of each substance is unique. Therefore, spectral information can be said to be the "fingerprint" of all things. The spectrometer can directly detect the spectral information of a substance and obtain the existence status and material composition of the target being measured. It is one of the important testing instruments in the fields of material characterization and chemical analysis. From the perspective of technological development, micro-spectrometers can be divided into four categories: dispersion type, narrowband filtering type, Fourier transform type, and computational reconstruction type.

[0003] The spectral chip of the spectrometer is used to receive and modulate incident light, and output the spectral information of the incident light based on the modulated incident light. Its light modulation effect is critical to improving the overall performance of the spectrometer.

[0004] Therefore, it is desirable to provide a spectral chip solution with improved light modulation effect. Utility Model Content

[0005] The embodiment of the present application provides a spectral chip, which ensures imaging quality by ensuring that a predetermined filter unit has signals at all wavelengths and can provide sufficient signals in a dark light environment or a monochromatic light environment.

[0006] According to one aspect of the present application, a spectral chip is provided, comprising: a light sensing area, wherein the light sensing area is composed of a photodetection layer and a light modulation layer located above the photodetection layer, wherein the light modulation layer comprises eight filter units formed by eight filter materials, and the eight filter materials and one filter unit without filter material are arranged in a 3×3 array.

[0007] In the above-mentioned spectral chip, the one filter unit without filter material is located in the middle of the 3×3 array.

[0008] In the above-mentioned spectral chip, one filter material corresponds to one filter unit, and one filter material corresponds to one or more physical pixels, and the 3×3 array corresponds to one spectral pixel.

[0009] In the above-mentioned spectrum chip, the eight filter materials include at least one IR filter material, and the thickness of the IR filter material is 0.5um to 1.2um.

[0010] In the above-mentioned spectrum chip, the thickness of the IR filter material is 0.5um-0.8um.

[0011] In the above-mentioned spectrum chip, the thickness of each filter material is the same, or the thickness of multiple filter materials are different according to different transmittance curves.

[0012] In the above-mentioned spectral chip, the transmission spectrum curves of the different types of filter materials have peak values ​​near 450nm, near 475nm, near 550nm, near 685nm and in the infrared band.

[0013] In the above-mentioned spectral chip, the array is a single layer, or the array partially includes two or more layers superimposed.

[0014] The above-mentioned spectral chip further includes: a microlens layer, which is arranged on the light modulation layer.

[0015] In the above-mentioned spectral chip, the microlens layer and the light modulation layer are aligned with the pixels of the photodetection layer; or, the microlens layer and the light modulation layer shrink toward the array center of the pixels of the photodetection layer to form a misalignment with the pixels of the photodetection layer.

[0016] In the above spectrum chip, the incident principal light angle is a, the material filling the filter material and the material of the microlens have a refractive index n1, the material of the filter material has a refractive index n2, the refractive index of air is n0, the translation amount of the filter material relative to the pixel is L2, the translation amount of the microlens relative to the filter material is L1, the thickness of the filter material is h2, and the total thickness of the spherical vertex of the microlens plus the filling material is h1, then:

[0017]

[0018] And the translation amount of the microlens relative to the pixel is L1+L2.

[0019] The spectral chip provided in the embodiment of the present application can ensure imaging quality by ensuring that the predetermined filtering unit has signals at all wavelengths and can also provide sufficient signals in a dark light environment or a monochromatic light environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present application will become clear to those of ordinary skill in the art. The drawings in the specification are only used for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0021] Figure 1 The figure shows a schematic diagram of a filter material setting scheme of a spectral chip according to an embodiment of the present application.

[0022] Figure 2 The diagram illustrates a first part of the production process flow of a spectral chip according to an embodiment of the present application.

[0023] Figure 3 The figure shows a schematic diagram of the second part of the production process flow of the spectral chip according to an embodiment of the present application.

[0024] Figure 4 A schematic diagram of a comparative example of a production process flow of a spectral chip according to an embodiment of the present application is illustrated.

[0025] FIG. 5A to FIG. 5F The diagram shows a schematic diagram of a spectral chip according to an embodiment of the present application in which the filter materials are periodically arranged in square units.

[0026] Figure 5G A schematic cross-sectional view of a filter material including blank pixels and a microlens array of a spectral chip according to an embodiment of the present application is illustrated.

[0027] Figure 6 The diagram shows a schematic diagram of a periodic arrangement of filter materials in a spectral chip in non-square units according to an embodiment of the present application.

[0028] Fig. 7A and Figure 7B A schematic diagram of an example of a microlens arrangement of a spectral chip according to an embodiment of the present application is illustrated.

[0029] Figure 8 A schematic diagram of an example of calculating the translation amount of the filter material and the microlens of the spectral chip according to an embodiment of the present application is illustrated.

[0030] Fig. 9 A schematic diagram of an example of a photodetection layer and a light modulation layer having a metal gate structure of a spectral chip according to an embodiment of the present application is illustrated.

[0031] FIG. 10A to FIG. 10C The figure shows a schematic diagram of a specific arrangement example of nine filter materials of a spectral chip according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] Below, the exemplary embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the exemplary embodiments described here.

[0033] In an embodiment of the present application, the spectral chip is mainly composed of a photodetection layer and a light modulation layer located above the photodetection layer. Here, the photodetection layer is usually implemented as an image sensor, such as a CMOS image sensor (CIS). The light modulation layer includes different types of filter materials, and the different types of filter materials mainly refer to different corresponding transmission spectra, that is, different types of filter materials have different transmittance curves. The filter material can be implemented as a dye, pigment or other material.

[0034] In a common spectral chip with CIS, the light sensing area of ​​CIS is the core area of ​​spectral image acquisition, and its performance determines indicators such as signal-to-noise ratio and dynamic range. This area is composed of m×n repeated pixel units, and the photoelectric conversion parts of all pixel units are exactly the same. All units can be divided into multiple groups of repeated pixels through different filter materials such as RGB, that is, R, G, and B filter materials, and then the corresponding algorithm is used to restore the color. In the technical solution of the present application, in order to obtain detailed information of the spectrum, the goal of spectral sensing can be achieved by only the design combination of color filter materials without modifying the basic design of the pixel.

[0035] According to the spectral chip of the embodiment of the present application, for example, it can be implemented as a multi-spectral sensor, which includes ① a light sensing area (i.e., located in the photoelectric detection layer), which is composed of a photoelectric detection layer (which can be understood as a plurality of at least partially identical pixels) and a light modulation layer; ② peripheral circuits and wiring. After the filter material is selected, the filter material is coated in a certain area within the light sensing area. Different filter materials will bring different modulation effects to light of different wavelengths, that is, different transmittances. Therefore, in the technical solution of the present application, the type of filter material can refer to different colors of filter materials, different materials of filter materials, or different thicknesses of filter materials, as long as the transmittance curves between the filter materials of each type are different. Moreover, the greater the difference in transmittance for different wavelengths between different filter materials, the better the recovery performance of the final spectral chip. That is, the spectral chip can be formed by applying n kinds of filter materials to the light sensing area, and one filter material can correspond to one physical pixel or multiple physical pixels, for example, one filter material corresponds to one physical pixel, one filter material corresponds to four physical pixels, or nine pixels, etc. The filter material and the corresponding physical pixels constitute a filter unit, and multiple (at least two) filter units constitute a spectral pixel, which serves as the minimum unit for restoring the spectral curve. In addition, the spectral chip includes at least one spectral pixel. For example, if the spectral chip is used to restore the spectral curve, the spectral pixel can be one. In some cases, it can also be used for multi-region spectral restoration, and the spectral pixel is at least one. If the spectral chip is used for spectral imaging, the number of spectral pixels is at least two. It should be noted that if the spectrum needs to be restored, the spectral pixel requires more filter units with different transmission spectra. In principle, it should be at least greater than two. However, for higher accuracy, the number of filter units required will also be greater. Accordingly, if the combination of filter materials to form different filter units is not considered, then in the technical solution of the present application, the number of filter materials should be greater than 2, preferably greater than or equal to 3. Figure 1 FIG. 1 is a schematic diagram of a filter material setting scheme for a spectral chip according to an embodiment of the present application. Figure 1 As shown, when there are nine kinds of filter materials, namely filter materials A, B, C, D, E, F, G, H, and I, the filter materials are formed on the upper end of the physical pixels to constitute corresponding filter units A, B, C, D, E, F, G, H, and I. Therefore, it can be considered that the filter units A, B, C, D, E, F, G, H, and I constitute spectral pixels.

[0036] Figure 2 FIG. 1 is a schematic diagram of the first part of the production process flow of the spectral chip according to an embodiment of the present application. Figure 2As shown, first, a pixel photosensitive layer 110 and a peripheral circuit 120 relative to the pixel photosensitive layer 110 are provided on a base layer 100, and a protection / planarization layer 130 is provided thereon. Then, a first filter material layer 140 corresponding to the color filter material 1 is formed by coating on the protection / planarization layer 130. After that, photolithography is performed by superimposing a photolithography mask 141 on the first filter material layer 140, and a first filter unit 142 corresponding to the molded color filter material 1 is obtained by development or etching.

[0037] Figure 3 FIG. 2 is a schematic diagram of the second part of the production process flow of the spectral chip according to an embodiment of the present application. Figure 3 As shown, in order to form the second filter unit 152, a second filter material layer 150 corresponding to the color filter material 2 is coated. Here, the second filter unit 152 and the first filter unit 151 can be different materials of the same material or different materials, as long as they have different transmittance curves as required. Similarly, the second filter material layer 150 corresponding to the color filter material 2 is formed by coating on the protective / planarizing layer 130 at a position other than the first filter unit 142. Afterwards, photolithography is performed by superimposing a photolithography mask 151 on the second filter material layer 150, and the second filter unit 152 corresponding to the molded color filter material 2 is obtained by development or etching. And similarly, taking the array composed of 3×3 filter units as described above as an example, the cross-sectional view shows 3 different materials as a period, and in fact, the above process of forming the filter unit is repeated 9 times.

[0038] That is, in the embodiment of the present application, the color filter material is coated on the surface of the wafer by a spin coating process, and the desired distribution is obtained by photolithography, development, and etching. By using a plurality of pre-designed and manufactured mask plates, the materials coated on the surface in sequence are developed into corresponding patterns. However, for some types of filter materials, because they are not transparent to the specific wavelength of light used in photolithography, that is, the transmittance is not high, the light cannot effectively reach a certain depth, causing the material to produce a photosensitive reaction. Therefore, at a position close to the surface where light can reach, the photoreaction can fully occur, but at a deeper position, the amount of light entering is low, the photoreaction is slow, resulting in poor molding.

[0039] Therefore, for the sake of manufacturing stability, for filter units whose transmittance for light of the predetermined wavelength used for lithography is less than a predetermined threshold, that is, for filter units that are insensitive to the lithography light source and difficult to form, considering that they are difficult to expose to light during the lithography process, they are not suitable for adjacent arrangement in the array, but should be separated as much as possible by filter units that are sensitive to the lithography light source and easy to form, that is, filter units whose transmittance for light of the predetermined wavelength used for lithography is greater than or equal to the predetermined threshold. That is, it can be understood that the spectral chip has at least one filter unit whose transmittance for light of the predetermined wavelength used for lithography is less than the predetermined threshold and a filter unit whose transmittance for light of the predetermined wavelength used for lithography is greater than or equal to the predetermined threshold, which are arranged adjacent to each other, that is, there is at least one filter unit that is easy to form and a filter unit that is difficult to form arranged adjacent to each other. That is, since all filter units need to be patterned by photolithography, and the filter units that are insensitive to the photolithography light source and difficult to form have poor forming effects due to their insensitivity to the photolithography light source during the photolithography process, if they are directly exposed or arranged adjacently, they are prone to collapse, missing or insufficient thickness at the edge of the pattern. These defects will reduce the filtering effect of the filter material and fail to achieve the expected filtering purpose (i.e., light leakage at the defective position). Therefore, it is necessary to use other filter units that are sensitive to the photolithography light source and easy to form to surround them, so that during photolithography, the filter units that are insensitive to the photolithography light source and difficult to form are filled in the surrounding area of ​​the filter units that have been formed and are sensitive to the photolithography light source and easy to form, so as to ensure the edge integrity of all filter units. The wavelength of the photolithography light source can be 436nm, 365nm, 248nm, 192nm and / or 14nm. The predetermined threshold value can be understood as the transmittance of the wavelength of light used for photolithography is between 3% and 70%, preferably 5% and 15%.

[0040] Figure 4 FIG. 1 is a schematic diagram showing a comparative example of a production process flow of a spectral chip according to an embodiment of the present application. Figure 4 As shown, when a filter unit that is sensitive to the photolithography light source and easy to shape is formed on the protection / planarization layer 130, its morphology after photolithography is normal, while when a filter unit that is insensitive to the photolithography light source and difficult to shape is formed, its edge after photolithography is thin and the cross section is arc-shaped, so that the light transmittance of the thinner and thicker areas is different. In addition, if these filter units are arranged adjacent to each other, the edge morphology will be such an arc, thereby affecting the filtering effect. Of course, those skilled in the art can understand that in addition to the arc shown in the figure, there may also be other defects such as missing corners.

[0041] In contrast, for the filter units that are insensitive to the photolithography light source and difficult to form, the filter units that are sensitive to the photolithography light source and easy to form can be formed first, and intervals can be formed between the units. Then, the filter units that are insensitive to the photolithography light source and difficult to form are coated at the positions of the intervals to fill in between the formed filter units that are sensitive to the photolithography light source and easy to form. Then, photolithography is performed, and the edges of the filter units that are insensitive to the photolithography light source and difficult to form will be restricted by the filter units that are sensitive to the photolithography light source and easy to form, so that no obvious defects, such as curved edges, will be formed, resulting in excessive thickness differences in the filter units.

[0042] Therefore, an embodiment of the present application provides a spectral chip, including a light sensing area, wherein the light sensing area is composed of a photodetection layer and a light modulation layer located above the photodetection layer, wherein the light modulation layer includes a plurality of filter units formed by different types of filter materials, the different types of filter materials have different transmittance curves, the different types of filter materials are arranged in a filter material unit array, and in the array, the filter units that are insensitive to the photolithography light source and difficult to form are not adjacent.

[0043] Furthermore, in the spectral chip according to the embodiment of the present application, in the array, a filter unit that is sensitive to the photolithography light source and easy to form is first formed, and then a filter unit that is insensitive to the photolithography light source and difficult to form is formed by filling the filter units that are sensitive to the photolithography light source and easy to form non-adjacently between the filter units that are sensitive to the photolithography light source and easy to form.

[0044] Furthermore, in the spectral chip according to the embodiment of the present application, preferably, one filter material corresponds to one filter unit, one filter unit corresponds to one or more physical pixels, and at least one filter unit corresponds to one spectral pixel.

[0045] In the technical solution of the present application, the typical thickness of the filter material is 0.5um to 2um. Adjusting the thickness within this range has the best optical advantage. If the thickness is too thin, the transmittance modulation effect of different wavelengths will deteriorate. If it exceeds 2um, the optical path will be too long, the optical design will be difficult, and the quantum efficiency will be reduced and the crosstalk will increase. In addition, the thickness of each filter material can be the same, or the thickness can be adjusted according to the requirements of the transmittance curve. In addition, in the embodiments of the present application, filter materials of the same type but different thicknesses can also be considered as different types of filter materials.

[0046] Therefore, in the spectral chip according to the embodiment of the present application, the thickness of the filter material is 0.5um to 2um.

[0047] Furthermore, in the above-mentioned spectrum chip, the thickness of each filter material, or the thickness of multiple filter materials, is different according to different transmittance curve requirements.

[0048] Furthermore, when the transmittance wavelengths of all filter materials are superimposed, they must completely cover the wavelength range required for the application (for example, covering the visible light and near-infrared bands of 380 to 1300 nm). And, preferably, the peaks and troughs of the transmittance curves of different types of filter materials do not overlap. Specifically, the transmittance curve of the same type of filter material can be adjusted by thickness so that the peaks and troughs of the transmittance curve do not overlap. Preferably, the transmittance curves of the selected different types of filter materials have peak values ​​at least near 450nm, near 475nm, near 550nm, near 685nm, and in the infrared band, so as to meet the requirements of realizing spectral restoration or spectral imaging in the visible light-infrared band.

[0049] Furthermore, in the above-mentioned spectral chip, preferably, the transmission spectrum curves of the different types of filter materials have peak values ​​near 450 nm, near 475 nm, near 550 nm, near 685 nm and in the infrared band.

[0050] In principle, the various filter materials in the present application are generally arranged in an n×n matrix and periodically covered along the pixel array; in special cases (such as line sensors), they can also be arranged linearly or rectangularly. FIG. 5A to FIG. 5F The figure shows a schematic diagram of the filter material of the spectrum chip according to the embodiment of the present application being arranged periodically in square units. FIG. 5A to FIG. 5F As shown, the numbers represent different types of filter materials, but do not specifically refer to a certain filter material, and the small squares represent physical pixels.

[0051] like Figure 5A As shown, the four colors of filter materials form a periodic 2×2 filter unit arrangement, which has the advantage of low cost and is superior to Figure 1 Specifically, with the same physical resolution, the total area of ​​2×2 is smaller and the manufacturing cost is lower. At the same time, because there are 4 different color channels involved in the calculation, the color reproduction is better than that of a sensor with only RGB colors.

[0052] like Figure 5B As shown, the 9 colors of filter materials form a periodic 3×3 filter unit arrangement, for example Figure 1 The fundamental advantage of this solution is that it can collect more spectral information. In some examples, it can also solve the problem of RGB camera's metamerism and inaccurate color reproduction.

[0053] like Figure 5CAs shown in the figure, 16 colors of filter materials form a periodic 4×4 filter unit arrangement, which has the advantage of high performance. Specifically, it collects more spectral information than 9 channels, so the spectrum restoration accuracy is higher and the spectral resolution is higher. However, because the area of ​​4×4 is larger than 3×3, under the same physical resolution, the physical resolution of the output image of this solution is lower; similarly, if an image with the same physical resolution is to be output, the physical resolution of the sensor is higher and the cost is higher.

[0054] like Figure 5D As shown, the 9 colors of filter materials form a periodic 6×6 filter unit arrangement, which has the advantage of fast output speed and is suitable for spectral chips that require high-speed output. Specifically, if the physical size of the sensor is the same, in this 6×6 arrangement scheme, first, the incident light area of ​​a single channel is larger, so the signal is stronger and the signal-to-noise ratio is higher, and sufficient external signals can be obtained in a shorter time; secondly, if the total physical resolution of the sensor is the same, when the area of ​​the same channel is enlarged, the total period is reduced, the output image resolution is reduced, and the processing and transmission speed is faster.

[0055] like Figure 5E As shown, 7 (or less) colors of filter materials form a periodic 3×3 filter unit arrangement, which is used in scenarios based on cost considerations or specific wavelengths. Specifically, in addition to being related to the chip area, the cost is also related to the number of different channels, because each different channel requires an operation step to produce. When there is a need to reduce costs, two or more pixel channels can be appropriately merged into the same channel to reduce production steps. In addition, if there is a higher sensitivity requirement for the light corresponding to a certain channel, this solution can also be used to use the signals of multiple pixels to enhance the acquisition capability of this band.

[0056] like Fig. 5FAs shown, 8 colors of filter materials form a periodic 3×3 filter unit arrangement, in which one pixel has no filter material (i.e., no filter material is set), that is, there is a blank pixel N, (if one filter material corresponds to multiple physical pixels to form a filter unit, then the number of blank pixels is preferably consistent, for example, one filter material is set above four physical pixels to form a filter unit, then the blank pixel is also composed of four physical pixels) suitable for high-sensitivity products. In addition, in this design, there can be one or more pixels without filter material, and this design without filter material is not limited to the periodic 3×3 filter unit arrangement. Specifically, the channel without filter material is transparent in ultraviolet, visible, and infrared, that is, it can collect signals of all the above wavelengths. Because this channel does not filter out part of the light, the amount of light entering is significantly higher than the surrounding pixels, and the signal strength of the full wavelength can be quickly sensed, which is suitable for darker scenes, or the signal strength of this channel can be used to adjust the exposure of other channels (such as adjusting the exposure time) to achieve the best effect. Preferably, in this solution, the filter unit (without filter material) corresponding to the blank pixel is located in the middle of the spectral pixel formed by the 3×3 filter units. The design of the N channel without filter material enables the channel to have signals at all wavelengths, so it can also provide sufficient signals in dark light environments or monochromatic light environments to ensure imaging quality. Furthermore, because the N channel has full-wavelength incidence, it sometimes causes the amount of light entering the channel to be too large. When the signals in other channels are weak, the N channel has reached saturation (overexposure) and becomes an invalid signal. In order to overcome this weakness, in a preferred embodiment, the N channel does not have filter materials and does not have microlenses. In this way, due to the lack of focusing of the microlens, its quantum efficiency is artificially reduced, which can effectively prevent it from being saturated (overexposure) in advance, while also ensuring the ability to collect full-wavelength signals.

[0057] It should be noted that the N channel can have a microlens (same as the microlens on other channels, used to enhance the dark light imaging effect), or it can have no microlens (detecting full wavelength signals in most environments and preventing overexposure). In this case, it is preferred to have no microlens. In the N channel, regardless of whether a microlens is set, the area at the same height as the filter material is filled with the same material as the microlens (flush with the lower surface of the microlens in other channels)

[0058] Specifically, in a preferred embodiment, 8 colors of filter materials form a periodic 3×3 filter unit arrangement, in which one pixel has no filter material, that is, there is a blank pixel N, wherein, Fig. 5F As shown, the blank pixel is located in the middle of the spectrum pixel composed of 3×3 filter units, wherein the spectrum chip further includes a microlens layer, and the microlens layer is located on the upper end of the filter material. In this embodiment, no microlens is provided at the blank pixel, that is, the incident light can directly reach the blank pixel without being modulated by the filter material. Figure 5G Here, Figure 5G A schematic cross-sectional view of a filter material including blank pixels and a microlens array of a spectral chip according to an embodiment of the present application is illustrated.

[0059] Furthermore, in the present embodiment, the filter material includes an IR filter material (for example, the IR filter material is defined as having a transmittance of >20% at wavelengths above about 790 nm and a transmittance of <20% at other wavelengths), and the thickness of the filter unit corresponding to the IR filter material is preferably 0.5um-1.2um, preferably 0.5um-0.8um, so that the filter unit corresponding to the IR filter material has a higher transmittance. Secondly, since the blank pixel is adjacent to the filter unit corresponding to the IR filter material and there is crosstalk (the absence of a microlens can make the crosstalk stronger to a certain extent), the light of the blank pixel will partially enter the filter unit corresponding to the IR filter material, thereby also helping to improve the signal strength of the filter unit corresponding to the IR filter material.

[0060] It should be noted that in some embodiments of the present invention, in order to obtain better effects (better transmission spectrum matrix), when designing the filter unit array (or spectral pixel), it may be necessary to arrange the filter units that are difficult to form adjacent to each other. At this time, some filter units that are difficult to form may be arranged adjacent to each other.

[0061] in addition, Figure 6 The figure shows a schematic diagram of the filter material of the spectral chip according to the embodiment of the present application being arranged periodically in non-square units. Figure 6 As shown, 8 colors of filter materials form a periodic 4×2 pixel arrangement, which is suitable for special scenarios, such as line sensors with only one or several rows of pixels used in professional fields such as industry.

[0062] Generally, an array composed of multiple materials is a single layer; two or more materials can also be stacked when a narrower transmittance peak or other requirements are required.

[0063] Therefore, in the spectral chip according to the embodiment of the present application, the different types of filter materials include an array composed of periodically arranged units, and the units include n×n square units, linear units or rectangular units.

[0064] Furthermore, in the above-mentioned spectral chip, the array is a single layer, or the array partially includes two or more layers stacked together.

[0065] In addition, in the spectral chip according to the embodiment of the present application, a microlens layer may be further included above the light modulation layer. In one example, the pixels of the light modulation layer, the microlens layer and the photodetection layer are completely aligned, such as Fig. 7AIn another example, when the incident main light angle CRA is large, the light modulation layer and the microlens can be shrunk toward the center of the array according to the angle and the refractive index and shape of the microlens to form a certain misalignment, so as to ensure that as much light as possible enters the pixel at the edge and reduce the crosstalk between pixels. Figure 7B shown. Fig. 7A and Figure 7B A schematic diagram of an example of a microlens arrangement of a spectral chip according to an embodiment of the present application is illustrated.

[0066] Therefore, in the spectral chip according to the embodiment of the present application, it further includes: a microlens layer, which is arranged on the light modulation layer, preferably, formed on the upper surface of the light modulation layer.

[0067] Furthermore, in the above-mentioned spectral chip, the microlens layer and the light modulation layer are aligned with the pixels of the photodetection layer; or, the microlens layer and the light modulation layer shrink toward the array center of the pixels of the photodetection layer to form a misalignment with the pixels of the photodetection layer.

[0068] Specifically, the translation amount of the microlens and the light modulation layer is related to the incident main light angle CRA. A simplified translation scheme is: when the CRA corresponding to each pixel is a, the translation amount of the filter material and the microlens can be simply calculated by the following method. It should be recognized that if the influence of crosstalk and uniformity needs to be considered more accurately, the translation amount calculated below should be optimized by wave optics simulation method.

[0069] In this simplified solution, the material filling the filter material and the microlens use the same refractive index material, for example, with a refractive index of n1, the filter material has a refractive index of n2, and the air has a refractive index of n0, and the case where there is an additional film on the upper surface of the pixel is not considered. If the pixel upper surface is considered to have other films, the refractive index needs to be further calculated based on the refractive index and its thickness.

[0070] Figure 8 FIG. 1 is a schematic diagram showing an example of calculating the translation amount of the filter material and the microlens of the spectral chip according to an embodiment of the present application. Figure 8 As shown, the incident angle of the light is a, the translation amount of the filter material relative to the pixel is L2, the translation amount of the microlens relative to the filter material is L1, the thickness of the filter material is h2, and the total thickness of the spherical vertex of the microlens plus the filling material is h1, then:

[0071]

[0072] And the translation amount of the microlens relative to the pixel is L1+L2.

[0073] In addition, in other examples, in a CIS with a metal grid structure such as a back-illuminated type, the filter layer can be integrated at the same height as the metal grid to shorten the optical path, such as Fig. 9 shown. Fig. 9 A schematic diagram of an example of a photodetection layer and a light modulation layer having a metal gate structure of a spectral chip according to an embodiment of the present application is illustrated.

[0074] It should be noted that, in other embodiments of the present application, the number of physical pixels corresponding to different filter materials may be different. For example, there are at least two filter materials, and the transmittance of one filter material is significantly greater than that of the other filter material. At this time, the loss of incident light with a large transmittance is small, and the response value received by the corresponding physical pixel will be larger, and the corresponding signal-to-noise ratio will also be larger, and the overall effect will be better. However, due to the large loss of incident light, the same number of physical pixels may not give a good effect. Therefore, in the embodiment of the present application, the number of physical pixels corresponding to the filter material with a larger transmittance is smaller than the number of physical pixels corresponding to the filter material with a smaller transmittance. For the transmittance, the transmittance curve can be integrated within a specific band range (generally understood as the working band range of the spectral chip, such as one or more bands in visible light, infrared, and / or ultraviolet). The larger the value, the greater the transmittance.

[0075] That is, in the spectral chip according to other embodiments of the present application, the first number of physical pixels of the filter unit corresponding to the first filter material with high transmittance is less than the second number of physical pixels of the filter unit corresponding to the second filter material with low transmittance.

[0076] The working principle of the spectral chip according to the embodiment of the present application will be described below. The intensity signal of the incident light at different wavelengths λ is recorded as x(λ), the transmission spectrum curve of the light modulation layer is recorded as T(λ), the light modulation layer has filter units of n kinds of filter materials, and the transmission spectra of the filter units corresponding to each filter material are different. Overall, the light modulation layer can be recorded as Ti(λ) (i=1,2,3,…,n). The corresponding physical pixels under each filter material detect the light intensity bi adjusted by the filter material.

[0077] The relationship between the spectral distribution of the incident light and the measured value of the image sensor can be expressed as follows:

[0078] bi=∫x(λ)*Ti(λ)*R(λ)dλ

[0079] Discretize it again and get:

[0080] bi=Σ(x(λ)*Ti(λ)*R(λ))

[0081] Where R(λ) is the response of the image sensor, expressed as:

[0082] Ai(λ)=Ti(λ)*R(λ),

[0083] The above formula can be expanded into matrix form:

[0084]

[0085] Among them, bi (i = 1, 2, 3, ..., n) is the response of the image sensor after the light to be measured passes through the light modulation layer, which corresponds to the light intensity measurement value of the photoelectric detection layer corresponding to the n filter units. When a physical pixel corresponds to a structural unit, it can be understood as the light intensity measurement value corresponding to n physical pixels, which is a vector of length n. A is the system's response to light of different wavelengths, which is determined by two factors: the transmittance of the filter structure and the quantum efficiency of the image sensor. A is a matrix, and each row vector corresponds to the response of the filter unit to incident light of different wavelengths. Here, the incident light is discretely and uniformly sampled, with a total of m sampling points. The number of columns of A is the same as the number of sampling points of the incident light. Here, x (λ) is the intensity of the incident light at different wavelengths λ, that is, the incident light spectrum to be measured.

[0086] On the basis of the above implementation, the spectral pixels are arrayed to realize a snapshot spectral imaging device.

[0087] In the embodiment of the present application, for the above Figure 1 In the scheme of nine filter materials shown, in a specific example, without considering the CIS quantum efficiency, the transmittance curves of the nine filter materials 1, 2, 3, 4, 5, 6, 7, 8, and 9 in the visible light and near-infrared bands may have the following characteristics:

[0088] Filter material 1 (R): Transmittance > 20% for wavelengths above about 580nm, and < 20% for other wavelengths;

[0089] Filter material 2 (G1): Transmittance > 20% at wavelengths between about 475 and 630 nm and greater than 690 nm, and < 20% at other wavelengths;

[0090] Filter material 3 (G2): Transmittance > 20% at wavelengths between about 475 and 610 nm and greater than 690 nm, and < 20% at other wavelengths;

[0091] Filter material 4 (G3): Transmittance > 20% at wavelengths between about 470 and 650 nm and greater than 660 nm, and < 20% at other wavelengths;

[0092] Filter material 5 (B): Transmittance > 20% at wavelengths < 520 nm and greater than 785 nm, and < 20% at other wavelengths;

[0093] Filter material 6 (C): Transmittance > 20% at wavelengths < 570 nm and greater than 730 nm, and < 20% at other wavelengths;

[0094] Filter material 7 (Y): Transmittance > 20% at wavelengths > 470 nm, < 20% at other wavelengths;

[0095] Filter material 8 (M): Transmittance <20% at wavelengths of about 520-580nm, >20% at other wavelengths;

[0096] Filter material 9 (IR): Transmittance > 20% for wavelengths above about 790nm, and < 20% for other wavelengths.

[0097] In addition, for the sake of manufacturing stability, the filter materials 1, 7, and 8 are difficult to expose during the photolithography process, so they cannot be arranged adjacent to each other and are separated by the filter materials 2, 3, and 4 as much as possible. Since all filter materials need to be patterned by photolithography, and the filter materials 1, 7, and 8 are not sensitive to the photolithography light source during the photolithography process, the effect is poor. If they are directly exposed or arranged adjacent to each other, it is easy to cause collapse, missing or insufficient thickness at the edge of each pattern. These defects will reduce the filtering effect of the filter material and fail to achieve the expected filtering purpose (i.e., light leakage at the defective position). Therefore, it is necessary to use other filter materials that are easy to shape to surround them. During photolithography, the filter materials that are difficult to shape are filled in the surrounding area of ​​the already formed easy-to-shape filter materials (2, 3, and 4) to ensure the edge integrity of all filter materials.

[0098] That is, assuming that there are any two filter materials that are not sensitive to the photolithography light source and are not easy to form in the spectrum chip, such as any two of filter materials 1, 7, and 8, the two are arranged as far apart as possible to prevent incomplete edges; if there are filter materials that are easy to form in the spectrum chip, such as filter materials 2, 3, and 4, the filter materials that are not easy to form can be filled in the adjacent parts of the filter materials that are easy to form, and preferably, the filter materials that are easy to form are arranged around the filter materials that are not easy to form. It should be noted that, generally speaking, the filter units corresponding to the spectrum chip are arranged periodically. Therefore, it is necessary to consider that when the filter materials are arranged in the overall spectrum chip, all the filter materials that are not easy to form are arranged as far apart as possible.

[0099] FIG. 10A to FIG. 10C FIG. 1 is a schematic diagram showing a specific arrangement example of nine filter materials of a spectrum chip according to an embodiment of the present application. FIG. 10A to FIG. 10CAs shown, 9 filter materials are arranged in a 3×3 array, and one filter material corresponds to 2×2 physical pixels. For example, the main setting is that filter materials 1, 7, and 8 are not adjacent to each other, and at least one filter material among filter materials 2, 3, and 4 is as adjacent to at least one filter material among filter materials 1, 7, and 8 as possible.

[0100] In addition, from the perspective of thickness, the thickness of each filter material can be the same, or the thickness can be adjusted according to the requirements of the transmittance curve, and the same type of filter materials can also be used. Preferably, the thickness of filter materials 1, 4 to 8 is between 0.5 and 0.8um, the thickness of filter material 2 is 0.6 to 0.7um, the thickness of filter material 3 is 0.8 to 1.0um, the thickness of filter material 4 is 0.5 to 0.6um, and the thickness of filter material 9 is 1 to 1.5um. In this way, the difference in transmittance curves between filter materials can be maximized, and to a certain extent, the requirements of the algorithm can be better met, thereby making the recovery effect better and ensuring the reliability of the manufacturing process. For example, in FIG. 10A to FIG. 10C In the example shown, the thickness of filter material 1 (R) is preferably 0.5um, the thickness of filter material 2 (G1) is preferably 0.7um, the thickness of filter material 3 (G2) is preferably 1um, the thickness of filter material 4 (G3) is preferably 0.5um, the thickness of filter material 5 (B) is preferably 0.7um, the thickness of filter material 6 (C) is preferably 0.6um, the thickness of filter material 7 (Y) is preferably 0.6um, the thickness of filter material 8 (M) is preferably 0.6um, and the thickness of filter material 9 (IR) is preferably 1.5um.

[0101] like Fig. 10A As shown, filter material 1, filter material 7, and filter material 8 are arranged separately. Specifically, filter material 4, filter material 3, filter material 5, and filter material 9 are arranged around filter material 7 in the spectrum chip, filter material 3, filter material 2, filter material 6, and filter material 5 are arranged around filter material 8, and filter material 2, filter material 4, filter material 9, and filter material 6 are arranged around filter material 1. It can be understood that in this embodiment, 3*3 filter units constitute a spectrum pixel, and the spectrum chip is obtained in a periodic array.

[0102] Same as above, Fig. 10B As shown, in the spectrum chip, filter material 7 is surrounded by filter material 6, filter material 9, filter material 2, and filter material 5, respectively; filter material 8 is surrounded by filter material 3, filter material 6, filter material 5, and filter material 4, respectively; filter material 1 is surrounded by filter material 9, filter material 3, filter material 4, and filter material 2.

[0103] Same as above, Fig. 10CAs shown, in the spectrum chip, filter material 7 is surrounded by filter material 2, filter material 9, filter material 3, and filter material 6, respectively; filter material 8 is surrounded by filter material 3, filter material 6, filter material 5, and filter material 4, respectively; filter material 1 is surrounded by filter material 4, filter material 5, filter material 9, and filter material 2.

[0104] Furthermore, in order to prevent crosstalk and improve performance, the filter material 9 is preferably adjacent to the filter material 5 and / or the filter material 6 to reduce crosstalk between wavelengths above 600 nm.

[0105] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0106] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0107] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0108] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0109] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A spectral chip, wherein: include: a light sensing region, the light sensing region being composed of a photoelectric detection layer and a light modulation layer located above the photoelectric detection layer, The light modulation layer includes eight filter units formed by eight filter materials, and the eight filter units and one filter unit without filter material are arranged in a 3×3 array.

2. The spectral chip according to claim 1, wherein: The one filter unit without filter material is located in the middle of the 3×3 array.

3. The spectral chip according to claim 1, wherein: One filter material corresponds to one filter unit, and one filter material corresponds to one or more physical pixels, and the 3×3 array corresponds to one spectral pixel.

4. The spectral chip according to claim 1, wherein: The eight filter materials include at least one IR filter material, and the thickness of the IR filter material is 0.5um-1.2um.

5. The spectral chip according to claim 4, wherein: The thickness of the IR filter material is 0.5um to 0.8um.

6. The spectral chip according to claim 1, wherein: The thickness of each filter material is the same, or the thickness of the multiple filter materials are different according to different transmittance curves.

7. The spectral chip according to claim 6, wherein: The transmission spectrum curves of the different types of filter materials have peak values ​​near 450 nm, near 475 nm, near 550 nm, near 685 nm and in the infrared band.

8. The spectral chip according to claim 1, wherein: The array is a single layer, or the array partially includes two or more layers stacked together.

9. The spectral chip according to claim 1, wherein: It further includes: a microlens layer, which is arranged on the light modulation layer.

10. The spectral chip according to claim 9, wherein: Further including: No microlens is arranged on the upper end of the filter unit where no filter material is arranged.

11. The spectral chip according to claim 9 or 10, wherein: The microlens layer and the light modulation layer are aligned with pixels of the photodetection layer; Alternatively, the microlens layer and the light modulation layer shrink toward the array center of the pixels of the photodetection layer to form a misalignment with the pixels of the photodetection layer.

12. The spectral chip according to claim 11, wherein: The incident principal light angle is a, the material filling the filter material and the material of the microlens have a refractive index n1, the material of the filter material has a refractive index n2, the refractive index of air is n0, the translation amount of the filter material relative to the pixel is L2, the translation amount of the microlens relative to the filter material is L1, the thickness of the filter material is h2, and the total thickness of the spherical vertex of the microlens plus the filling material is h1, then: And the translation amount of the microlens relative to the pixel is L1+L2.

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