Combination chip structure with wide free spectral range

Abstract

The application provides a combined chip structure with a wide free spectral range, which comprises four spectral imaging chip structures, any of which comprises a pixel photosensitive unit and a narrow-band filter film, the narrow-band filter film being integrally deposited and grown on the pixel photosensitive unit, the narrow-band filter film comprising a plurality of FP cavity structures arranged in a line scanning mode, when spectral imaging is performed by using the combined chip structure, the four spectral imaging chip structures are arranged in a line along a spectral dimension, the heights of the plurality of FP cavity structures of the narrow-band filter film change along the spectral dimension, and the spectral ranges covered by the four spectral imaging chip structures are all different. The application can improve the free spectral range.

Description

Technical Field

[0001] This invention relates to the field of spectral analysis technology, and to a combined chip structure with a wide free spectral range. Background Technology

[0002] Each pixel in a standard RGB color image contains data for color identification. However, the photosensitive spectral range of a standard RGB color image is too wide, making it impossible to distinguish many targets with similar spectral information. To differentiate between targets with similar spectral information, narrowband filtering of the image sensor's response spectral bands is required to extract the target's characteristic spectral bands and achieve target differentiation. Since the characteristic spectral bands of various targets to be identified differ, narrowband filtering at different wavelengths needs to be implemented at different pixels.

[0003] Variable cavity Fabry-Perot (FP) spectral filters can be integrated onto CMOS image sensors, achieving unified imaging sensor functionality. The materials used in the fabrication of FP filters are semiconductor materials compatible with CMOS sensors. The optical cavity of a FP filter includes a light-transmitting layer, an upper mirror, and a lower mirror. Bragg mirrors, made of semiconductor materials and fabricated through overlapping growth, achieve a reflectivity of over 99% and can be used as FP cavity mirrors.

[0004] The center wavelength of the filter can be changed by altering the cavity length of the FP cavity through a variable cavity structure. However, due to the limitations of semiconductor materials compatible with CMOS technology, such as the narrow free spectral bandwidth of SINx and SiO2 stacked Bragg mirrors (100nm narrower in visible light and 170nm in near-infrared), it is impossible to cover the visible spectrum (400-1000nm) with a single structural design. Therefore, improving the free spectral range is a challenge for multispectral imaging micro sensors. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0006] Therefore, the present invention provides a combined chip structure with a wide free spectral range.

[0007] The technical solution of this invention is as follows: This invention provides a combined chip structure with a wide free spectral range. This combined chip structure includes four spectral imaging chip structures. Each of the spectral imaging chip structures includes a pixel photosensitive unit and a narrowband filter. The narrowband filter is integrally deposited and grown on the pixel photosensitive unit. The narrowband filter includes multiple FP cavity structures distributed in a line scan. When performing spectral imaging using the combined chip structure, the four spectral imaging chip structures are arranged in a straight line along the spectral dimension. The height of the multiple FP cavity structures of the narrowband filter varies along the spectral dimension. The spectral ranges covered by the four spectral imaging chip structures are all different.

[0008] Furthermore, along the spectral dimension, the four spectral imaging chip structures sequentially cover spectral ranges of 400–510 nm, 510–630 nm, 640–810 nm, and 800–1000 nm.

[0009] Furthermore, along the spectral dimension, the four spectral imaging chip structures are, in order, a line scan chip with 16 spectral bands in the range of 400nm to 510nm, a line scan chip with 32 spectral bands in the range of 510nm to 630nm, a line scan chip with 32 spectral bands in the range of 640nm to 810nm, and a line scan chip with 32 spectral bands in the range of 800nm ​​to 1000nm; the center wavelength tuning ranges corresponding to the four spectral imaging chip structures are, in order, a center wavelength range tuned from 408nm to 502nm, a center wavelength range tuned from 512nm to 623nm, a center wavelength range tuned from 645nm to 790nm, and a center wavelength range tuned from 810nm to 992nm.

[0010] Furthermore, the film structure of any of the aforementioned spectral imaging chip structures is Sub|H(LH)^S 2nL(HL)^SH|Air, where n is the film thickness adjustment coefficient, S is the number of stacking operations, H is a high refractive index material, and L is a low refractive index material. The film thickness adjustment coefficients n of the four spectral imaging chip structures are all different, and the film thickness adjustment coefficients n are evenly distributed among the corresponding spectral bands.

[0011] Furthermore, along the spectral dimension, the range of the film thickness adjustment coefficient n corresponding to the four spectral imaging chip structures is designed to be 0.745~1.557, 0.67~1.439, 0.643~1.425, and 0.652~1.437, respectively.

[0012] Furthermore, any of the spectral imaging chip structures also includes a first matching layer, which is integrally deposited and grown on the pixel photosensitive unit. The narrowband filter is integrally deposited and grown on the first matching layer. The first matching layer is used to transition the optical admittance between the narrowband filter and the pixel photosensitive unit to improve the peak transmittance of the center wavelength.

[0013] Furthermore, any of the spectral imaging chip structures also includes a second matching layer, which is integrally deposited and grown on the narrowband filter film. The second matching layer is used to improve the center wavelength transmittance of the spectral imaging chip structure.

[0014] Furthermore, the film structure of the first matching layer is Q1, which includes L or HL, where H is a high refractive index material and L is a low refractive index material.

[0015] Furthermore, the film structure of the first matching layer is Q1, and the film structure of the second matching layer is Q2. Q1 includes HL or LHL, and Q2 includes LH or LHL. When Q1 is HL, Q2 is LHL; when Q1 is LHL, Q2 is LH. H is a high refractive index material, and L is a low refractive index material.

[0016] Furthermore, each of the aforementioned spectral imaging chip structures also includes a cutoff filter, which is attached to the narrowband filter film. The cutoff filter is used to cut off interference bands, and the cutoff filters of the four spectral imaging chip structures cut off different interference bands.

[0017] By applying the above technical solution, four spectral imaging chip structures are designed in a straight line along the spectral dimension. The height of multiple FP cavity structures of the narrowband filter film of the arbitrary spectral imaging chip structure varies along the spectral dimension. The four spectral imaging chip structures cover different spectral ranges respectively, resulting in a combined chip structure with a wide free spectral range. By simply adjusting the spectral range covered by the four spectral imaging chip structures, it is possible to cover the visible spectrum (400-1000nm). This overcomes the limitation of the free spectral range due to the difference in refractive index of materials and broadens the free spectral range of narrowband filtering of image sensors. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0019] Figure 1 A schematic diagram of a 16-band tuned filter in the 400nm–510nm range provided according to a specific embodiment of the present invention is shown.

[0020] Figure 2 A schematic diagram of a 32-band tuned filter in the 510nm to 630nm range provided according to a specific embodiment of the present invention is shown.

[0021] Figure 3 A schematic diagram of a 32-band tuned filter in the 640nm to 810nm range provided according to a specific embodiment of the present invention is shown.

[0022] Figure 4 This diagram illustrates a 32-band tuning filter in the 800nm–1000nm range according to a specific embodiment of the present invention.

[0023] Figure 5 A schematic diagram of the structure of the spectral imaging chip provided according to the fifth embodiment of the present invention is shown;

[0024] Figure 6 This diagram illustrates the center wavelength transmittance with and without a matching layer according to a specific embodiment of the present invention.

[0025] Figure 7 A schematic diagram of the center wavelength transmittance of the unmatched layer, the substrate-side matching layer, and the air-side matching layer provided according to a specific embodiment of the present invention is shown.

[0026] Figure 8 A schematic diagram of the center wavelength transmittance of the unmatched layer, the L-matched layer, and the HL-matched layer provided according to a specific embodiment of the present invention is shown.

[0027] The above figures include the following reference numerals:

[0028] 10. Pixel photosensitive unit; 20. Narrow-band filter; 50. First matching layer. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0032] As a first embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. The combined chip structure includes four spectral imaging chip structures. Each of the spectral imaging chip structures includes a pixel photosensitive unit 10 and a narrowband filter 20. The narrowband filter 20 is integrally deposited and grown on the pixel photosensitive unit 10. The narrowband filter 20 includes multiple FP cavity structures distributed in a line scan. When performing spectral imaging using the combined chip structure, the four spectral imaging chip structures are arranged in a line along the spectral dimension. The height of the multiple FP cavity structures of the narrowband filter varies along the spectral dimension. The spectral ranges covered by the four spectral imaging chip structures are all different.

[0033] In this embodiment of the invention, the pixel photosensitive unit 10 is used to realize image acquisition and data readout, and can be, for example, a CMOS sensor; the narrowband filter 20 is used to realize tunability at the center wavelength of the desired band, and any FP cavity structure of the narrowband filter includes a lower reflector, a light-transmitting layer and an upper reflector stacked from bottom to top.

[0034] In the first embodiment of the present invention, by designing four spectral imaging chip structures arranged in a straight line along the spectral dimension, and by varying the height of multiple FP cavity structures of the narrowband filter film of the arbitrary spectral imaging chip structure along the spectral dimension, the four spectral imaging chip structures cover different spectral ranges respectively, resulting in a combined chip structure with a wide free spectral range. By simply adjusting the spectral range covered by the four spectral imaging chip structures, it is possible to cover the visible spectrum (400-1000nm), breaking through the limitation of the free spectral range due to the difference in refractive index of materials, and broadening the free spectral range of the narrowband filter of the image sensor.

[0035] As a second embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure, based on the first embodiment, further defines the spectral range covered by the four spectral imaging chips. In this embodiment, along the spectral direction, the four spectral imaging chip structures sequentially cover spectral ranges of 400–510 nm, 510–630 nm, 640–810 nm, and 800–1000 nm. In the second embodiment of the present invention, by designing the spectral ranges covered by the four spectral shaping chip structures along the spectral direction to be sequentially 400–510 nm, 510–630 nm, 640–810 nm, and 800–1000 nm, the combined chip structure can cover the light-emitting spectral range of 400–1000 nm.

[0036] As a third embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure is based on the second embodiment, and further defines the spectral range covered by the four spectral imaging chips. In this embodiment, along the spectral dimension, the four spectral imaging chip structures are, in sequence, a line scan chip with 16 spectral bands in the range of 400nm to 510nm, a line scan chip with 32 spectral bands in the range of 510nm to 630nm, a line scan chip with 32 spectral bands in the range of 640nm to 810nm, and a line scan chip with 32 spectral bands in the range of 800nm ​​to 1000nm. The center wavelength tuning ranges corresponding to the four spectral imaging chip structures are, in sequence, a center wavelength range tuned from 408nm to 502nm, a center wavelength range tuned from 512nm to 623nm, a center wavelength range tuned from 645nm to 790nm, and a center wavelength range tuned from 810nm to 992nm. In the third embodiment of the present invention, by designing the number of spectral bands of the four spectral imaging chips, a combined chip structure with more than 100 spectral bands is obtained, which makes the application scenarios of the combined chip structure wider and the resolution higher, wherein the spectral resolution does not exceed 10nm. In addition, by designing the center wavelength tuning range, bandpass filtering of 400-510nm, 510-630nm, 640-810nm and 800-1000nm is realized.

[0037] In this embodiment of the invention, the center wavelength of the Bragg mirror corresponding to the 400-510nm spectral range is set at 440nm, the center wavelength of the Bragg mirror corresponding to the 510-630nm spectral range is set at 560nm, the center wavelength of the Bragg mirror corresponding to the 640-810nm spectral range is set at 710nm, and the center wavelength of the Bragg mirror corresponding to the 800-1000nm spectral range is set at 890nm.

[0038] As a fourth embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure is based on the third embodiment, further defining the film structure of the four spectral imaging chips. In this embodiment, the film structure of any of the spectral imaging chip structures is Sub|H(LH)^S12nL(HL)^S1 H|Air, where n is the film thickness adjustment coefficient, S1 is the number of stacking operations, H is a high refractive index material, and L is a low refractive index material. The film thickness adjustment coefficient n of the four spectral imaging chip structures is different, and the film thickness adjustment coefficient n is evenly distributed among the corresponding spectral bands. In the fourth embodiment of the present invention, by designing the film structure of the four spectral chips, a line scan chip with 16 spectral bands in the range of 400nm to 510nm, a line scan chip with 32 spectral bands in the range of 510nm to 630nm, a line scan chip with 32 spectral bands in the range of 640nm to 810nm, and a line scan chip with 32 spectral bands in the range of 800nm ​​to 1000nm can be obtained.

[0039] In this embodiment of the invention, the film thickness adjustment coefficients in the film structures of the four spectral imaging chips are respectively limited. Preferably, the ranges of the film thickness adjustment coefficients n corresponding to the four spectral imaging chip structures are designed as 0.745–1.557, 0.67–1.439, 0.643–1.425, and 0.652–1.437, respectively. By designing the film thickness adjustment coefficients of the four spectral chips, line scan chips with 16 spectral bands in the range of 400 nm to 510 nm, 32 spectral bands in the range of 510 nm to 630 nm, 32 spectral bands in the range of 640 nm to 810 nm, and 32 spectral bands in the range of 800 nm to 1000 nm can be obtained. The optimized film structures of the four spectral chips are shown in Tables 1, 2, 3, and 4, respectively, and the corresponding transmittance curves are shown in Tables 1, 2, 3, and 4. Figure 1-4 As shown (the middle band has been simplified).

[0040] Table 1

[0041]

[0042]

[0043] Table 2

[0044]

[0045]

[0046] Table 3

[0047]

[0048] Table 4

[0049]

[0050] As a fifth embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure further defines the arbitrary spectral imaging chip structure based on the above embodiments. In this embodiment, such as... Figure 5-6 As shown, any of the spectral imaging chip structures further includes a first matching layer 50, which is integrally deposited and grown on the pixel photosensitive unit 10. A narrowband filter film 20 is integrally deposited and grown on the first matching layer 50. The first matching layer 50 is used to transition the optical admittance between the narrowband filter film 20 and the pixel photosensitive unit 10 to improve the peak transmittance of the center wavelength.

[0051] In the fifth embodiment of the present invention, the spectral imaging chip structure integrally deposits a first matching layer on the pixel photosensitive unit and integrally deposits and grows a narrowband filter on the first matching layer. There are no gaps between the narrowband filter, the first matching layer, and the pixel photosensitive unit, resulting in high spectral transmittance, reduced energy loss, and a one-time fabrication process that is not affected by external environmental contamination, thus exhibiting better robustness, higher fabrication efficiency, and higher integration. In this invention, because the refractive index difference between the narrowband filter material and the pixel photosensitive unit material of the image sensor is significant during the growth process, direct growth would lead to refractive index mismatch and a decrease in the center wavelength peak transmittance, resulting in low quantum efficiency of the spectral imaging system and affecting imaging performance. Therefore, by setting a first matching layer between the pixel photosensitive unit and the narrowband filter, the problem of refractive index mismatch and decreased center wavelength peak transmittance can be effectively overcome, effectively improving the center wavelength peak transmittance of the spectral imaging chip structure. While increasing transmittance, the bandwidth is reduced, allowing for the fabrication of more spectral bands and the acquisition of more spectral lines within a fixed cutoff range. Furthermore, the overlap between adjacent spectral bands is reduced, leading to better resolution during data processing.

[0052] As a sixth embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure is based on the fifth embodiment, with further definition of the film structure of the first matching layer. In this embodiment, the film structure Q1 of the first matching layer 50 includes L or HL, where H represents a high refractive index material and L represents a low refractive index material. That is, after stacking the first matching layer, the film structure of any spectral imaging chip structure can also be configured as Sub|Q1 H(LH)^S12nL(HL)^S1 H|Air, where Q1 is the film structure of the first matching layer 50, H(LH)^S12nL(HL)^S1 H is the film structure of the narrowband filter 20, n is the film thickness adjustment coefficient of the narrowband filter 20, H is a high refractive index material, L is a low refractive index material, and S1 and S2 are the stacking times. By configuring the specific model structure of the spectral imaging chip structure, tunable filtering at the center of the desired band and improved peak transmittance at the center wavelength can be achieved.

[0053] Specifically, in this sixth embodiment, any spectral imaging chip structure can be represented by an equivalent interface, whose reflection, transmission, and phase characteristics are determined by the combined admittance of the incident medium and the equivalent interface. Essentially, the effect of any thin film layer can be viewed as altering the admittance of the equivalent interface, thereby changing the optical properties of the thin film system. Optical admittance is the ratio of electric field strength to magnetic field strength; in the optical band, optical admittance is numerically equal to the refractive index.

[0054] On the substrate (refractive index n) s When the beam has only one thin film (i.e., any H or L, a single-layer thin film), its characteristic matrix is ​​as follows when the beam is incident perpendicularly from air (n0 = 1):

[0055]

[0056] The above formula contains all the useful parameters of the thin film, where, B is the electric field strength, C is the magnetic field strength, δ1 is the phase thickness of the first thin film, n1 is the refractive index of the first thin film, d1 is the film thickness of the first thin film, λ is the center wavelength, θ1 is the incident angle of the first thin film, η1 is the tilt optical admittance of the first thin film, and η s The tilted optical admittance is the base, and i is a complex number.

[0057] Depend on From the expression of the matrix, we can see that when the effective optical thickness of the thin film is an integer multiple of 1 / 4 wavelength, that is...

[0058]

[0059] Where n is the refractive index, d is the film thickness, and θ is the incident angle.

[0060] or its phase thickness is Integer multiples of, i.e.

[0061]

[0062] Where δ is the phase thickness of the film;

[0063] The characteristic matrix of the thin film is

[0064]

[0065]

[0066] R = [(η0 - η] s ) / (η0+η s )] 2

[0067] Where Y represents optical admittance, R is reflectivity, η0 is optical admittance at the center wavelength λ, and the characteristic matrix of the thin film is an identity matrix. At the reference wavelength λ, it has no effect on the reflection or transmission characteristics of the film system. This thin film is called a dummy layer.

[0068] Taking the currently designed spectral imaging chip structure as an example, the narrowband filter film is essentially a dummy layer, which does not affect the spectral transmittance. The film structure is as follows:

[0069] Sub|H(LH)^32nL(HL)^3H|Air

[0070] At the center wavelength λ, the middle cavity layer is an even multiple of λ / 4 and has no effect on the transmittance of the center wavelength, so it can be removed. In the remaining structure, two adjacent high refractive index film layers form a λ / 2 layer, which can also be removed. In this way, all film layers are removed, and finally, the Sub|Air structure is obtained.

[0071] Due to the difference in refractive index between the substrate and air, residual reflectivity inevitably exists at the center wavelength. Transmittance at the center wavelength can be improved by adding a matching layer. With the introduction of the concept of a dummy layer, the design problem of the matching layer becomes primarily a substrate-related antireflection coating design. For Sub|Air, a thick, low-refractive-index layer can be added near the substrate or air side to act as a matching layer.

[0072] For the case of a low refractive index spacer layer (i.e., 2nL), the half-width is expressed by the following formula:

[0073]

[0074] Where x represents the total number of high-refractive-index layers in the multilayer reflective film. Without a matching layer, the multilayer reflective film refers to the upper Bragg mirror; with a matching layer, it refers to the multilayer film before the 2L spacer layer, including the high-refractive-index layers within the spacer layer. When the film system structure is Sub|H(LH)^32nL(HL)^3H|Air, X = 4; when the film system structure is Sub|HL H(LH)^32nL(HL)^3H LHL|Air, X = 5. m represents the interference order, and n... H n is the refractive index of a high-refractive-index material. L The refractive index is the refractive index of the low-refractive-index material.

[0075] According to equation (1), the half-width of the pre-matching layer membrane system is:

[0076]

[0077] The half-width after adding a low-refractive-index matching layer to the substrate side is:

[0078]

[0079] Based on the half-width (WWHM) after adding a matching layer to the substrate side, it can be seen that the addition of the matching layer improves the filter transmittance while changing the WWHM, and the change in WWHM affects the resolution. Adding a matching layer closer to the substrate can reduce the WWHM while improving the filter transmittance. A reduced WWHM allows for the preparation of more spectral bands within a limited cutoff range, reduces the overlap between adjacent spectral bands, and better identifies the characteristics of different spectral bands. However, a too narrow WWHM is not conducive to signal recognition. Therefore, the WWHM can be adjusted according to the actual number of spectral bands and the required signal recognition rate.

[0080] As a seventh embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure with a wide free spectral range further defines the film system of the spectral chip structure. In this spectral imaging chip structure, S1 = 5-7, where Sub is the substrate Si, Air is air, H represents one of the high refractive index materials Ta2O5, Ti3O5, TiO2, Si3N4, and Nb2O5, and L represents one or a mixture of low refractive index materials SiO2, MgF2, and Al2O3.

[0081] As an eighth embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure with a wide free spectral range is based on the fifth embodiment, but introduces a second matching layer. The second matching layer is integrally deposited and grown on the narrowband filter 20. The second matching layer is used to improve the center wavelength peak transmittance of the spectral imaging chip structure. In this embodiment, a first matching layer is disposed on the substrate side and a second matching layer is disposed on the air side. The addition of the first matching layer and the second matching layer improves the transmittance of the filter while changing the half-width. Figure 7 As shown, adding a matching layer to the substrate side reduces the half-width at half-maximum (WWHM), while adding it to the air side increases it. To make the bandwidth with and without a matching layer close to that without a matching layer, matching layers can be added simultaneously to both the substrate and air sides, thus ensuring that the WWHM remains unchanged.

[0082] As a ninth embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure with a wide free spectral range is based on the spectral imaging chip structure provided in the above embodiments, and the film structure of the spectral imaging chip structure is specifically defined. In this embodiment, the film structure is Sub|Q1 H(LH)^S12nL(HL)^S1 H Q2|Air, where Q1 is the film structure of the first matching layer 50, H(LH)^S12nL(HL)^S1 H is the film structure of the narrowband filter 20, n is the film thickness adjustment coefficient of the narrowband filter 20, Q2 is the film structure of the second matching layer, H is a high refractive index material, L is a low refractive index material, and S1 is the number of stacking times.

[0083] As a tenth embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure with a wide free spectral range is based on the ninth embodiment, with specific definitions for the first matching layer and the second matching layer. In this embodiment, the film structure is Sub|HL H(LH)^32nL(HL)^3H LHL|Air, and its half-width is... To obtain, where λ is the center wavelength, m represents the interference order, and n H n is the refractive index of a high-refractive-index material. L η is the refractive index of a low-refractive-index material. s The tilted optical admittance of the substrate. As a specific embodiment of the present invention, the half-width of the spectral imaging chip structure is...

[0084] As an eleventh embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure with a wide free spectral range further defines the film structure of the spectral imaging chip structure based on the above embodiments. In this embodiment, the film structure with a low refractive index layer added to the substrate side is Sub|LH(LH)^32nL(HL)^3H|Air. The film structure with a high refractive index layer and a low refractive index layer added to the substrate side is Sub|HL H(LH)^32nL(HL)^3H|Air. The transmittance curve is shown below. Figure 8 As shown, after adding the matching layer L, the transmittance of the center wavelength is 92.78%; after adding the matching layer HL, the transmittance of the center wavelength is 94.68%, which is even higher.

[0085] As a twelfth embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. The arbitrary spectrum imaging chip structure of the combined chip structure with a wide free spectral range includes a pixel photosensitive unit 10, a narrowband filter 20, and a third matching layer. The pixel photosensitive unit 10 is used to realize image acquisition and data readout. The narrowband filter 20 is integrally deposited and grown on the pixel photosensitive unit 10. The narrowband filter 20 is used to realize tunability of the center wavelength in the desired band. The third matching layer is integrally deposited and grown on the narrowband filter 20. The third matching layer is used to improve the peak transmittance of the center wavelength of the spectral imaging chip structure.

[0086] In this embodiment, considering that the refractive index difference between the film material and the pixel photosensitive unit material of the image sensor is large during the growth process of the narrowband filter film, direct growth will lead to refractive index mismatch and a decrease in the center wavelength peak transmittance, which will result in low quantum efficiency of the spectral imaging system and affect the imaging effect. Therefore, by integrally growing a third matching layer on the upper layer of the narrowband filter film, the problem of refractive index mismatch and decrease in center wavelength peak transmittance can be effectively overcome, and the center wavelength peak transmittance of the spectral imaging chip structure can be effectively improved.

[0087] As the thirteenth embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure with a wide free spectral range is based on the twelfth embodiment, but with a defined film structure for the spectral imaging chip. The film structure of this spectral imaging chip structure is Sub|(HL)^S1 H2nL H(LH)^S2 Q3|Air, where (HL)^S1H2nL H(LH)^S2 is the film structure of the narrowband filter 20, n is the film thickness adjustment coefficient of the narrowband filter 20, Q3 is the film structure of the third matching layer, H is a high refractive index material, L is a low refractive index material, and S1 and S2 are the number of stacking operations.

[0088] Specifically, in this invention, the film structure selection of the matching layer of the spectral imaging chip structure is shown in Table 1. Q1 and Q2 have a corresponding relationship: when Q1 is L, there is no Q2; when Q2 is L, there is no Q1; when Q1 is HL, there is no Q2 or Q2 is LHL; when Q1 is LHL, Q2 is LH.

[0089] Table 5 Selection of Matching Layer Membrane System Structure

[0090] Q1 Q2 Equivalent to L <![CDATA[ Sub|L|Air (basal side) L <![CDATA[ Sub|L|Air (Air side) HL <![CDATA[ Sub|HL|Air (basal side) HL LHL <![CDATA[ Sub|L|Air (Air side) LHL LH <![CDATA[ Sub|L|Air (basal side)

[0091] As the fourteenth embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure with a wide free spectral range is based on the twelfth embodiment, but the determination of the half-width of the spectral imaging chip structure is defined. In this embodiment, the half-width of the spectral imaging chip structure can be determined according to... To obtain, where λ is the center wavelength, x represents the total number of high refractive index layers in the multilayer reflective film, m represents the interference order, and n H n is the refractive index of a high-refractive-index material. L is the refractive index of a low-refractive-index material.

[0092] As the fifteenth embodiment of the present invention, a combined chip structure with a wide free spectral range is provided. This combined chip structure with a wide free spectral range is based on the fifth embodiment, which limits the arbitrary spectral imaging chip structure. Each of the spectral imaging chip structures also includes a cutoff filter. The cutoff filter is attached to the narrowband filter film. The cutoff filter is used to cut off interference bands. The cutoff filters of the four spectral imaging chip structures cut off different interference bands.

[0093] In this embodiment of the invention, each of the four spectral imaging chip structures includes a cutoff filter. The cutoff filter is attached to the narrowband filter film. The cutoff filters of the four spectral imaging chip structures cut off different interference bands, ensuring that all chip structures can achieve cutoff of their respective interference bands, and greatly simplifying the manufacturing process.

[0094] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0095] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A combined chip structure with a wide free spectral range, characterized in that, The combined chip structure includes four spectral imaging chip structures. Each of the spectral imaging chip structures includes a pixel photosensitive unit (10) and a narrowband filter (20). The narrowband filter (20) is integrally deposited and grown on the pixel photosensitive unit (10). The narrowband filter (20) includes multiple FP cavity structures distributed in a line scan. When performing spectral imaging using the combined chip structure, the four spectral imaging chip structures are arranged in a line along the spectral dimension. The height of the multiple FP cavity structures of the narrowband filter (20) varies along the spectral dimension. The spectral ranges covered by the four spectral imaging chip structures are all different. Along the spectral dimension, the four spectral imaging chip structures sequentially cover spectral ranges of 400–510 nm, 510–630 nm, 640–810 nm, and 800–1000 nm. The four spectral imaging chip structures are, respectively, a 16-band linear scanning chip in the 400 nm–510 nm range, a 32-band linear scanning chip in the 510 nm–630 nm range, a 32-band linear scanning chip in the 640 nm–810 nm range, and a 32-band linear scanning chip in the 800 nm–1000 nm range. The corresponding center wavelength tuning ranges for the four spectral imaging chip structures are, respectively, a center wavelength range tuned from 408 nm to 502 nm, a center wavelength range tuned from 512 nm to 623 nm, a center wavelength range tuned from 645 nm to 790 nm, and a center wavelength range tuned from 810 nm to 992 nm. The film structure of any of the spectral imaging chip structures is Sub|H(LH)^S1 2nL (HL)^S1 H|Air, where n is the film thickness adjustment coefficient of the narrowband filter (20), S1 is the number of stacking, H is a high refractive index material, and L is a low refractive index material. The film thickness adjustment coefficient n of the four spectral imaging chip structures is different, and the film thickness adjustment coefficient n is evenly distributed among the corresponding spectral bands. Along the spectral dimension, the values ​​of the film thickness adjustment coefficient n corresponding to the four spectral imaging chip structures are designed to be 0.745~1.557, 0.67~1.439, 0.643~1.425, and 0.652~1.437, respectively. Any of the spectral imaging chip structures further includes a first matching layer (50), which is integrally deposited on the pixel photosensitive unit (10), and the narrowband filter (20) is integrally deposited on the first matching layer (50). The first matching layer (50) is used to transition the optical admittance between the narrowband filter (20) and the pixel photosensitive unit (10) to improve the center wavelength peak transmittance. Any of the spectral imaging chip structures further includes a second matching layer, which is integrally deposited on the narrowband filter (20). The second matching layer is used to improve the center wavelength transmittance of the spectral imaging chip structure.

2. The combined chip structure with a wide free spectral range according to claim 1, characterized in that, The first matching layer (50) has a film structure of Q1, which includes L or HL, where H is a high refractive index material and L is a low refractive index material.

3. The combined chip structure with a wide free spectral range according to claim 2, characterized in that, The first matching layer (50) has a film structure of Q1 and the second matching layer has a film structure of Q2. Q1 includes HL or LHL and Q2 includes LH or LHL. When Q1 is HL, Q2 is LHL; when Q1 is LHL, Q2 is LH. H is a high refractive index material and L is a low refractive index material.

4. The combined chip structure with a wide free spectral range according to claim 1, characterized in that, Each of the aforementioned spectral imaging chip structures also includes a cutoff filter, which is attached to the narrowband filter film (20). The cutoff filter is used to cut off interference bands, and the cutoff filters of the four spectral imaging chip structures cut off different interference bands.

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