Color filter and image processing apparatus

Abstract

The invention discloses a color filter and an image processing device, the color filter comprises a first dielectric layer, a filter layer, a transition layer and a substrate layer, and the first dielectric layer, the filter layer, the transition layer and the substrate layer are sequentially stacked in a first direction; the light filtering layer comprises at least one light filtering unit, the light filtering unit comprises a plurality of double-layer structural bodies, the double-layer structural bodies are periodically arranged on the light filtering layer, each double-layer structural body comprises a metal layer and a second dielectric layer, and the metal layers and the second dielectric layers are sequentially arranged in a stacked mode in the first direction. One side, far away from the metal layer, of the second dielectric layer is connected with the transition layer, and the light filtering unit is arranged to selectively transmit light with a target wavelength through a plurality of double-layer structural bodies; the refractive index of the substrate layer is larger than the refractive index of the first dielectric layer, the refractive index of the metal layer and the refractive index of the second dielectric layer. According to the technical scheme, high transmittance of light with the target wavelength can be achieved, and the requirement for high-resolution image processing is met.

Description

Technical Field

[0001] This application relates to the field of optical filter technology, and more particularly to a color filter and an image processing device. Background Technology

[0002] In modern digital technology, color filters are indispensable optical components, widely used in image processing devices such as mobile phone screens, televisions, computer monitors, and image sensors in digital cameras. Their basic function is to selectively transmit light of specific colors (wavelengths). White light in nature is composed of a mixture of various colors, with red, green, and blue considered the "optical primary colors." An RGB color filter array (CFA) consists of numerous tiny R, G, and B filter units. When white light shines on the image, the red filter unit only allows red light to pass through; similarly, the green and blue filter units only allow light of their corresponding colors to pass through. In this way, display devices can mix colors to create full-color images, and imaging devices can capture and record color information. Therefore, the performance of RGB color filters, especially their light transmittance, directly affects the brightness and energy consumption of display devices, as well as the image quality of imaging devices.

[0003] Currently, existing RGB color filters are mainly divided into filters based on the principle of chemical dyes and filters based on the principle of structural colors, depending on the coloring method. Among them, filters based on the principle of chemical dyes are mainly based on chemically synthesized colors and achieve color filtering by absorbing light of specific wavelengths. This absorption principle directly leads to their generally low transmittance (usually between 40% and 60%), which makes it difficult to meet the needs of high-resolution image processing. Filters based on the principle of structural color derive their color from the resonant interaction between light and nanostructure arrays, providing a powerful technical route to replace traditional chemical dyes. However, achieving high transmittance still faces challenges. The main reason is that low-refractive-index substrates are conducive to forming strong resonant modes at the interface between nanostructures and air, resulting in good structural color display and filtering effects. Therefore, most filters based on the principle of structural color currently rely on low-refractive-index substrates (such as glass and SiO2). However, the optoelectronic devices (such as CMOS devices) below are usually made of high-refractive-index materials. As a result, when filtered light enters the high-refractive-index device from the low-refractive-index substrate, the huge refractive index difference at the interface will produce significant Fresnel reflection, resulting in a large loss of light energy. This significantly reduces the light flux entering the optoelectronic device below, making it difficult to achieve efficient light transmission and utilization. In other words, the overall transmittance efficiency of traditional structural color filters is also low, making it difficult to meet the requirements of high-resolution image processing. Summary of the Invention

[0004] The purpose of this application is to provide a color filter and an image processing device that aims to improve the problem that the light transmittance (i.e., "transmittance") of existing color filters is generally low and cannot meet the requirements of high-resolution image processing.

[0005] To achieve this objective, embodiments of this application provide a color filter, the color filter comprising a first dielectric layer, a filter layer, a transition layer and a substrate layer, wherein the first dielectric layer, the filter layer, the transition layer and the substrate layer are sequentially stacked along a first direction; The filter layer includes at least one filter unit, the filter unit includes multiple double-layer structures, and the multiple double-layer structures are periodically arranged in the filter layer. The double-layer structure includes a metal layer and a second dielectric layer. The metal layer and the second dielectric layer are stacked sequentially in the first direction, such that the side of the second dielectric layer away from the metal layer is connected to the transition layer. The filter unit is configured to selectively transmit light of a target wavelength through the multiple double-layer structures. The refractive index of the substrate layer is greater than that of the first dielectric layer, the metal layer, and the second dielectric layer.

[0006] Optionally, in some embodiments of this application, the target wavelength of light is any one of the light with the center wavelength of red light, the center wavelength of green light, and the center wavelength of blue light.

[0007] Optionally, in some embodiments of this application, the cross-section of the double-layer structure in the second direction is a circle or a polygon, and the second direction is perpendicular to the first direction.

[0008] Optionally, in some embodiments of this application, the material of the metal layer is selected from any one of gold, silver, aluminum, copper, and alloys; and / or, The material of the second dielectric layer is selected from any one of silicon dioxide, silicon nitride, aluminum oxide, and titanium oxide.

[0009] Optionally, in some embodiments of this application, the filter layer further includes a filler that fills the gaps between the respective double-layer structures; The material of the filler is the same as the material of the first dielectric layer, or the material of the filler, the material of the first dielectric layer, and the material of the transition layer are all the same.

[0010] Optionally, in some embodiments of this application, a plurality of the dual-layer structures are arranged in an Nx × Ny matrix on the filter layer, wherein the value of Nx is a positive integer greater than or equal to 5, and the value of Ny is a positive integer greater than or equal to 5.

[0011] Optionally, in some embodiments of this application, the filtering unit is configured to adjust the value of the target wavelength by changing at least one of the values ​​of Nx, Ny, the material of each layer of the double-layer structure, the size of the double-layer structure, the distance between two adjacent double-layer structures, and the material of the substrate layer.

[0012] Optionally, in some embodiments of this application, the filtering unit is configured to adjust the bandwidth and transmittance peak of the transmission spectrum by changing at least one of the materials of each layer of the double-layer structure, the distance between two adjacent double-layer structures, and the material of the substrate layer.

[0013] Optionally, in some embodiments of this application, at least one filter unit includes a red filter unit, a green filter unit, and a blue filter unit, and each of the double-layer structures is a cylinder; wherein, In the red filter unit, the distance between two adjacent double-layer structures is 273 nm to 313 nm, the diameter of each double-layer structure is 122 nm to 162 nm, the thickness of the metal layer in the first direction is 20 nm to 40 nm, the thickness of the second dielectric layer in the first direction is 200 nm to 240 nm, and the thickness of the portion of the transition layer corresponding to the red filter unit in the first direction is 20 nm to 40 nm. In the green filter unit, the distance between two adjacent double-layer structures is 320 nm to 360 nm, the diameter of each double-layer structure is 142 nm to 182 nm, the thickness of the metal layer in the first direction is 30 nm to 50 nm, the thickness of the second dielectric layer in the first direction is 225 nm to 265 nm, and the thickness of the transition layer corresponding to the red filter unit in the first direction is 45 nm to 65 nm. In the blue filter unit, the distance between two adjacent double-layer structures is 174 nm to 214 nm, the diameter of each double-layer structure is 75 nm to 100 nm, the thickness of the metal layer in the first direction is 45 nm to 65 nm, the thickness of the second dielectric layer in the first direction is 190 nm to 230 nm, and the thickness of the transition layer corresponding to the red filter unit in the first direction is 10 nm to 30 nm.

[0014] Furthermore, to achieve this objective, embodiments of this application also provide an image processing apparatus, which includes the color filter of any of the above-mentioned methods.

[0015] The color filter and image processing device provided in this application, through the aforementioned structural configuration, use a high-refractive-index substrate (i.e., a substrate layer with a refractive index greater than that of other layers) instead of a traditional low-refractive-index substrate for the color filter. The core of this approach lies in constructing and utilizing the coupling of two resonant modes: one is the localized surface plasmon resonance or lattice resonance generated by the periodic metal-dielectric bilayer nanostructures (i.e., multiple periodically arranged bilayer structures) of each filter unit; the other is the Fabry-Perot (FP) microcavity resonance formed by the high-refractive-index substrate and the upper metal layer (which can be considered a partial reflector). When the incident light wavelength satisfies the FP resonance condition, a vertically oriented standing wave field is formed within the substrate layer, greatly enhancing the local energy density of light near the substrate interface. This FP resonant mode synergistically couples with the resonant states of the nanostructures of each filter unit, enabling the reconstruction of the light field distribution and phase at the interface. The key effect is that the destructive interference generated by this coupling effectively cancels out the strong Fresnel reflection that would normally be caused by the large refractive index difference between the high-refractive-index substrate and the upper dielectric layer. This allows the filtered light to be efficiently coupled into the substrate layer, significantly improving the total transmittance and bringing it close to the theoretical limit. Thus, this technical solution can achieve high transmittance for the target wavelength, meeting the requirements of high-resolution image processing. Therefore, this technical solution effectively addresses the problem that existing color filters generally have low transmittance, making it difficult to meet the demands of high-resolution image processing. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0018] Figure 1 This is a schematic diagram of the structure of the color filter according to an embodiment of this application; Figure 2 for Figure 1 A schematic diagram of a two-layer structure of the color filter shown. Figure 3 for Figure 1 Another schematic diagram of the two-layer structure of the color filter shown; Figure 4 for Figure 1 A schematic diagram of the array structure of the two-layer structure of the color filter shown; Figure 5 for Figure 1 The diagram shows a first structural schematic of the three-color filter unit of the color filter shown. Figure 6 for Figure 1 The diagram shows a second structural schematic of the three-color filter unit of the color filter shown. Figure 7 for Figure 1 The diagram shows a third structure of the three-color filter unit of the color filter shown. Figure 8 yes Figure 5 The transmission spectrum of the three colors of light from the color filter is shown. Figure 9 yes Figure 5 The diagram shows the variation of red light transmittance with wavelength when the color filter faces different incident angles. Figure 10 yes Figure 5 The diagram shows the variation of green light transmittance with wavelength when the color filter faces different incident angles. Figure 11 yes Figure 5 The diagram shows the variation of blue light transmittance with wavelength when the color filter faces different incident angles. Figure 12 yes Figure 6 The transmission spectrum of the three colors of light from the color filter is shown. Figure 13 yes Figure 7 The transmission spectrum of the three colors of light from the color filter is shown.

[0019] Illustration: 10. Color filter; 11. First dielectric layer; 12. Filter layer; 121. Red light filter unit; 122. Green light filter unit; 123. Blue light filter unit; 124. Double-layer structure; 1241. Metal layer; 1242. Second dielectric layer; 125. Filler; 13. Transition layer; 14. Substrate layer. Detailed Implementation

[0020] To make the inventive objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component centrally located at the same time.

[0022] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] Please see Figures 1 to 4 As shown, in one embodiment, this application provides a color filter 10, which includes a first dielectric layer 11, a filter layer 12, a transition layer 13, and a substrate layer 14. The first dielectric layer 11, the filter layer 12, the transition layer 13, and the substrate layer 14 are arranged along a first direction (i.e., Figure 1 The filter layer 12 is stacked sequentially in the direction indicated by the middle arrow X. The filter layer 12 includes at least one filter unit, which includes multiple double-layer structures 124 arranged periodically in the filter layer 12. Each double-layer structure 124 includes a metal layer 1241 and a second dielectric layer 1242. The metal layer 1241 and the second dielectric layer 1242 are stacked sequentially in a first direction, such that the side of the second dielectric layer 1242 away from the metal layer 1241 is connected to the transition layer 13. The filter unit is configured to selectively transmit light of a target wavelength through the multiple double-layer structures 124. The refractive index of the substrate layer 14 is greater than the refractive index of the first dielectric layer 11, the refractive index of the metal layer 1241, and the refractive index of the second dielectric layer 1242.

[0024] It should be noted that the color filter 10 of this application embodiment is mainly applied in image processing devices such as mobile phone screens, televisions, computer monitors, and image sensors of digital cameras to achieve the basic function of selectively transmitting light of a specific color (wavelength). That is, the color filter 10 can achieve the filtering function of one color through each filtering unit, that is, selectively transmitting light of the wavelength corresponding to that color. When the color filter 10 is specifically an RGB color filter 10, the target wavelength of light can be any one of the light of the red center wavelength, the light of the green center wavelength, and the light of the blue center wavelength. That is, when the filtering unit is set to selectively transmit light of the red center wavelength through multiple double-layer structures 124, it can be a red filtering unit to achieve the red light filtering function. When the filtering unit is set to selectively transmit light of the green center wavelength through multiple double-layer structures 124, it can be a green filtering unit to achieve the green light filtering function. When the filtering unit is set to selectively transmit light of the blue center wavelength through multiple double-layer structures 124, it can be a blue filtering unit to achieve the blue light filtering function.

[0025] In this way, the color filter 10 of this embodiment, through the above-described structural configuration, uses a high-refractive-index substrate (i.e., substrate layer 14 with a refractive index greater than that of other layers) instead of a traditional low-refractive-index substrate. Its core lies in constructing and utilizing the coupling of two resonant modes: one is the localized surface plasmon resonance or lattice resonance generated by the periodic metal-dielectric bilayer nanostructures (i.e., multiple periodically arranged bilayer structures 124) of each filter unit; the other is the Fabry-Perot (FP) microcavity resonance formed by the high-refractive-index substrate and the upper metal layer 1241 (which can be considered a partial reflector). When the incident light wavelength meets the FP resonance condition, a vertically oriented standing wave field is formed within the substrate layer 14, greatly enhancing the local energy density of light near the substrate interface. This FP resonant mode synergistically couples with the nanostructure resonant states of each filter unit, enabling the reconstruction of the light field distribution and phase at the interface. The key effect is that the destructive interference generated by this coupling effectively cancels out the strong Fresnel reflection that would normally be caused by the huge refractive index difference between the high-refractive-index substrate and the upper dielectric layer. This allows the filtered light to be efficiently coupled into the substrate layer 14, significantly improving the total transmittance and bringing it close to the theoretical limit. Thus, this technical solution can achieve high transmittance for the target wavelength, meeting the requirements of high-resolution image processing.

[0026] In some examples, such as Figure 2 and Figure 3 As shown, the double-layer structure 124 is in the second direction (i.e. Figure 1The cross-section along the direction indicated by the middle arrow Y is circular or polygonal, with the second direction perpendicular to the first direction. Thus, the bilayer structure 124, with its circular or polygonal cross-section perpendicular to the stacking direction, can more effectively modulate the electromagnetic field distribution of locally incident light through its symmetrical or specific edge shapes. This geometric characteristic helps optimize the resonant modes of the nanostructure (i.e., the bilayer structure 124), enhancing its coupling efficiency with Fabry-Perot cavity modes, thereby achieving stable and efficient filtering and transmission performance over a wider range of angles and wavelengths.

[0027] In some examples, such as Figure 1 , Figure 2 and Figure 3 As shown, the metal layer 1241 is made of any one of gold, silver, aluminum, copper, or alloys. Thus, through the above structural configuration, since metals such as gold, silver, aluminum, copper, or alloys possess excellent plasmon resonance characteristics in the visible and near-infrared bands, they can efficiently excite and support the strong localized surface plasmon resonance required by the filter unit, which is the physical basis for achieving highly selective wavelength filtering. Simultaneously, the optical constants (especially the complex refractive index) of these materials can be well matched with the Fabry-Perot resonator formed by the high-refractive-index substrate, working synergistically to maximize the suppression of interface reflection and improve overall transmittance. Therefore, selecting the above materials as the metal layer 1241 can further achieve high transmittance for the target wavelength, meeting the requirements of high-resolution image processing.

[0028] It should be noted that the alloy in this example can specifically be a gold-silver (Au-Ag), gold-copper (Au-Cu), or aluminum-silicon (Al-Si) alloy system. These alloy materials can achieve an optimal balance between surface plasmon resonance frequency, material stability, and fabrication processability by adjusting the composition ratio. For example, gold-silver alloys can combine the high performance of silver with the chemical stability of gold, thereby optimizing the optical performance of the filter and the reliability of the device.

[0029] In some examples, such as Figures 1 to 2 As shown, the material of the second dielectric layer 1242 is selected from any one of silicon dioxide, silicon nitride, aluminum oxide, and titanium oxide. Thus, with the above structural configuration, since materials such as silicon dioxide, silicon nitride, aluminum oxide, or titanium oxide have high transparency and controllable refractive index, they can form an effective resonant unit together with the metal layer 1241. Furthermore, by adjusting their thickness and refractive index, the center wavelength and bandwidth of the filter unit can be precisely controlled. In addition, these dielectric materials have good interface compatibility and structural stability with the metal layer 1241 and the transition layer 13, which helps ensure the reliability and durability of the filter unit's filtering performance.

[0030] In some examples, such as Figure 1As shown, the filter layer 12 also includes fillers 125 filling the gaps between the various double-layer structures 124. The filler 125 is made of the same material as the first dielectric layer 11, or the filler 125, the first dielectric layer 11, and the transition layer 13 are all made of the same material. By using the same material as the first dielectric layer 11 or the transition layer 13, the filler 125 ensures that the entire filter layer 12 region has a uniform background refractive index, which effectively suppresses parasitic scattering caused by non-uniform media, thereby maintaining the purity and efficiency of the filter unit resonance. Secondly, this material consistency simplifies the fabrication process of the multilayer structure, enhances the interface stability and mechanical integrity between layers, and helps improve the overall reliability and yield of the device.

[0031] In some examples, such as Figure 1 and Figure 4 As shown, multiple double-layer structures 124 are arranged in an Nx × Ny matrix on the filter layer 12, where Nx and Ny are both positive integers greater than or equal to 5. By designing each filter unit as a periodic matrix arrangement of at least 5x5 double-layer structures 124, a sufficiently large periodic area is ensured for each filter unit, thereby enabling the excitation of clear and stable lattice resonances or diffraction modes. This ordered macroscopic periodicity effectively suppresses optical noise caused by random defects, ensuring the uniformity and high purity of the filtered spectrum of the corresponding filter unit. Furthermore, the large-scale periodic arrangement is a necessary condition for achieving efficient and controllable coupling with the Fabry-Perot resonance formed on the high-refractive-index substrate, thus achieving near-theoretical high transmittance at the entire device scale.

[0032] In some examples, such as Figures 1 to 4 As shown, the filter unit is configured to adjust the target wavelength by changing at least one of the following: the value of Nx, the value of Ny, the material of each layer of the double-layer structure 124, the size of the double-layer structure 124, the distance between two adjacent double-layer structures 124, and the material of the substrate layer 14. Thus, by adjusting multiple degrees of freedom such as the period, unit size, material, and unit spacing of the double-layer structure 124, a high degree of design flexibility is provided for precise control of the target wavelength. This multi-parameter collaborative design method allows for independent and precise "customization" of the spectral response of the filter unit for specific applications (such as red, green, and blue filtering). Ultimately, this enables the efficient fabrication of filter arrays covering a wide wavelength range and with stable performance based on the same basic process platform.

[0033] It should be noted that the materials of each layer of the double-layer structure 124 in this example specifically refer to the materials of the metal layer 1241 and the second dielectric layer 1242. The metal layer 1241 can be selected from any one of gold, silver, aluminum, copper, and alloys. The material of the second dielectric layer 1242 is selected from any one of silicon dioxide, silicon nitride, aluminum oxide, and titanium oxide. The dimensions of the double-layer structure 124 in this example may specifically include the thickness of the double-layer structure 124 in the first direction (which can generally also be considered as the thickness of the corresponding filter layer 12 in the first direction), the side length (corresponding to a polygonal cross-section), or the diameter (corresponding to a circular cross-section) of the cross-section of the double-layer structure 124 in the second direction. The material of the substrate layer 14 in this example can specifically be selected from any one of silicon (Si), gallium arsenide (GaAs), sapphire (Al2O3), or high-refractive-index glass (such as glass with a refractive index n>1.8).

[0034] In some examples, such as Figures 1 to 4 As shown, the filter unit is configured to adjust the bandwidth and transmittance peak of the transmission spectrum by changing at least one of the following: the material of each layer of the double-layer structure 124, the distance between two adjacent double-layer structures 124, and the material of the substrate layer 14. Thus, by adjusting the material of the double-layer structure 124, the unit spacing, and the substrate material, the coupling strength and mode quality factor of the resonant unit (i.e., the corresponding filter unit) can be directly changed, thereby achieving fine control of the transmission spectrum bandwidth. Simultaneously, the synergistic optimization of these parameters can effectively control the coupling efficiency of the Fabry-Perot resonance and the nanostructure resonance, thereby precisely adjusting the transmittance peak value. Furthermore, this multi-dimensional design freedom allows the color filter 10 to flexibly balance the different application requirements of narrowband high selectivity and high throughput transmittance at the target wavelength.

[0035] Based on simulation results, the following specific examples further illustrate the above embodiments: In some examples, such as Figure 5As shown, at least one filter unit includes a red filter unit, a green filter unit, and a blue filter unit, and each double-layer structure 124 is a cylinder. In the red filter unit, the distance between two adjacent double-layer structures 124 is 273 nm to 313 nm, the diameter of each double-layer structure 124 is 122 nm to 162 nm, the thickness of the metal layer 1241 in the first direction is 20 nm to 40 nm, the thickness of the second dielectric layer 1242 in the first direction is 200 nm to 240 nm, and the thickness of the transition layer 13 corresponding to the red filter unit in the first direction is 20 nm to 40 nm. In the green filter unit, the distance between two adjacent double-layer structures 124 is 320 nm to 360 nm, the diameter of each double-layer structure 124 is 142 nm to 182 nm, the thickness of the metal layer 1241 in the first direction is 30 nm to 50 nm, the thickness of the second dielectric layer 1242 in the first direction is 225 nm to 265 nm, and the thickness of the transition layer 13 corresponding to the red filter unit in the first direction is 45 nm to 65 nm. In the blue filter unit, the distance between two adjacent double-layer structures 124 is 174 nm to 214 nm, the diameter of each double-layer structure 124 is 75 nm to 100 nm, the thickness of the metal layer 1241 in the first direction is 45 nm to 65 nm, the thickness of the second dielectric layer 1242 in the first direction is 190 nm to 230 nm, and the thickness of the transition layer 13 corresponding to the red filter unit in the first direction is 10 nm to 30 nm. Thus, through the above-mentioned specific parameter design, an optimized structural size system can be established for each of the red, green, and blue color filter units. By precisely matching the resonance conditions corresponding to each color band, these parameters ensure that each filter unit can simultaneously excite efficient nanostructure resonance and Fabry-Perot cavity resonance at its target wavelength (red, green, and blue light). The final effect is to realize a high-performance color filter array that can achieve high transmittance and high color purity in the visible light band, and suppress crosstalk to the greatest extent, meeting the needs of high-resolution imaging and display applications.

[0036] Furthermore, in this example, the first dielectric layer 11, the filter layer 12, and the transition layer 13 can all be filled with silicon dioxide with a refractive index of 1.45, that is, the refractive index of the first dielectric layer 11, the refractive index of the filter layer 12, and the refractive index of the transition layer 13 are all 1.45. In the double-layer structure 124 in this example, the metal layer 1241 is made of aluminum dielectric with a thickness of h1, and the second dielectric layer 1242 is made of silicon nitride dielectric with a thickness of h2 and a refractive index of 2.1. The substrate layer 14 in this example is made of aluminum gallium arsenide dielectric with a refractive index of 3.8. By adjusting the above parameters, the output color can be controlled. Figure 8 As shown in the figure, the relationship between the transmittance and wavelength of the corresponding filters, calculated using the Rigorous Coupled-Wave Analysis (RCWA) algorithm, demonstrates that the maximum transmittance is 80% for red light with a center wavelength of 660 nm, 75% for green light with a center wavelength of 540 nm, and 75% for blue light with a center wavelength of 450 nm. All three exhibit high optical transmittance efficiency. Furthermore, the figure also shows that the transmittance of other colors is effectively suppressed, ensuring optimized spectral selectivity and optical performance. For the red filter unit, as... Figure 9 As shown, when the incident angle increases from 0° to 8°, the red light transmittance increases from 80% to 82%, and when the incident angle decreases from 0° to -8°, the red light transmittance decreases slightly from 80% to 77%. Furthermore, neither increasing nor decreasing the incident angle excites higher-order modes, indicating that the proposed color filter 10 exhibits high insensitivity to changes in the incident angle. For the green filter unit, as... Figure 10 As shown, when the incident angle increases from 0° to 8°, the green light transmittance increases from 75% to 80%. When the incident angle decreases from 0° to -8°, the red light transmittance decreases slightly from 75% to 72%, and no higher-order modes are excited regardless of whether the incident angle is increased or decreased. This also indicates that the proposed color filter 10 exhibits high insensitivity to changes in the incident angle. For the blue filter unit, as... Figure 11 As shown, when the incident angle increases from 0° to 8°, the blue light transmittance increases from 76% to 81%, and when the incident angle decreases from 0° to -8°, the blue light transmittance decreases slightly from 76% to 73%. Furthermore, no higher-order modes are excited regardless of whether the incident angle is increased or decreased. This also indicates that the proposed color filter 10 is highly insensitive to changes in the incident angle.

[0037] In some examples, such as Figure 6 As shown, the thickness of the metal layer 1241 (i.e., the value of h1) and the thickness of the second dielectric layer 1242 (i.e., the value of h2) of each double-layer structure 124 in the red, green, and blue filter units can be set to the same value. At this time, as... Figure 12 As shown in the figure, the relationship between the filter transmittance and wavelength, calculated using the Rigorous Coupled-Wave Analysis (RCWA) algorithm, reveals the following simulation results: Red light has a center wavelength of 700 nm and a maximum transmittance of 82%; green light has a center wavelength of 540 nm and a maximum transmittance of 80%; and blue light has a center wavelength of 470 nm and a maximum transmittance of 78%. All three exhibit high optical transmittance efficiency. This demonstrates that high-performance filtering can be achieved while maintaining identical layer thicknesses in the double-layer structure 124 for the red, green, and blue color channels, indicating that the same mechanism can also be used to implement filtering.

[0038] In some examples, such as Figure 8 As shown, in addition to setting the thickness (i.e., the value of h1) of the metal layer 1241 and the thickness (i.e., the value of h2) of the second dielectric layer 1242 of each double-layer structure 124 in the red, green, and blue filter units to be the same, the thickness of the transition layer 13 corresponding to the red, green, and blue filter units can also be set to be the same. At this time, as... Figure 13 As shown in the figure, the relationship between the transmittance of the corresponding filter and the wavelength is calculated using the Rigorous Coupled-Wave Analysis (RCWA) algorithm. Simulation results show that the maximum transmittance is 75% for red light with a center wavelength of 650 nm, 90% for green light with a center wavelength of 530 nm, and 89% for blue light with a center wavelength of 440 nm. This demonstrates that even with identical thicknesses in the red, green, and blue filter units of color filter 10, high-performance filtering can still be achieved, indicating that the same mechanism can be used to implement filtering functionality.

[0039] In one embodiment, this application also provides an image processing apparatus, which includes the color filter 10 of the above embodiment. Thus, since the image processing apparatus of this application uses the color filter 10 of the above embodiment, it can achieve the same technical effects as the color filter 10 described above, and will not be repeated here.

[0040] In some examples, the image processing device may specifically be any one of a CMOS image sensor, a liquid crystal display, a machine vision system, or a miniature spectrometer, to enable these image processing devices to selectively transmit light of a specific color (wavelength).

[0041] In some examples, the image processing device may specifically be an image sensor, which includes a color filter 10 and a photoelectric conversion layer. The photoelectric conversion layer is stacked on the side of the substrate layer 14 of the color filter 10 away from the transition layer 13. In use, the filter layer 12 of the color filter 10 selectively transmits different colors of light in response to specific wavelengths. The photoelectric conversion layer converts the light signal passing through the color filter 10 into a corresponding electrical signal, thereby enabling the perception of color information.

[0042] In some examples, the image processing device may specifically be a color display device, which includes a color filter 10 and a backlight. The backlight is stacked on the side of the substrate layer 14 of the color filter 10 away from the transition layer 13. When this color display device is in use, light is emitted from the bottommost backlight, passes upward through the filter layer 12, and is modulated into light of a specific color. Thus, by arranging the various filter units of the color filter 10 in a reasonable manner, a full-color image can be synthesized on the display screen.

[0043] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A color filter, characterized in that, The color filter includes a first dielectric layer, a filter layer, a transition layer, and a substrate layer, wherein the first dielectric layer, the filter layer, the transition layer, and the substrate layer are stacked sequentially along a first direction; The filter layer includes at least one filter unit, the filter unit includes multiple double-layer structures, and the multiple double-layer structures are periodically arranged in the filter layer. The double-layer structure includes a metal layer and a second dielectric layer. The metal layer and the second dielectric layer are stacked sequentially in the first direction, such that the side of the second dielectric layer away from the metal layer is connected to the transition layer. The filter unit is configured to selectively transmit light of a target wavelength through the multiple double-layer structures. The refractive index of the substrate layer is greater than that of the first dielectric layer, the metal layer, and the second dielectric layer.

2. The color filter according to claim 1, characterized in that, The target wavelength of light is any one of the following: the center wavelength of red light, the center wavelength of green light, and the center wavelength of blue light.

3. The color filter according to claim 1, characterized in that, The cross-section of the double-layer structure in the second direction is a circle or a polygon, and the second direction is perpendicular to the first direction.

4. The color filter according to claim 1, characterized in that, The metal layer is made of any one of gold, silver, aluminum, copper, and alloys; and / or, The material of the second dielectric layer is selected from any one of silicon dioxide, silicon nitride, aluminum oxide, and titanium oxide.

5. The color filter according to claim 1, characterized in that, The filter layer also includes a filler that fills the gaps between the various double-layer structures; The material of the filler is the same as the material of the first dielectric layer, or the material of the filler, the material of the first dielectric layer, and the material of the transition layer are all the same.

6. The color filter according to any one of claims 1-5, characterized in that, Multiple dual-layer structures are arranged in an Nx × Ny matrix on the filter layer, where Nx is a positive integer greater than or equal to 5 and Ny is a positive integer greater than or equal to 5.

7. The color filter according to claim 6, characterized in that, The filtering unit is configured to adjust the target wavelength by changing at least one of the following: the value of Nx, the value of Ny, the material of each layer of the double-layer structure, the size of the double-layer structure, the distance between two adjacent double-layer structures, and the material of the substrate layer.

8. The color filter according to claim 6, characterized in that, The filtering unit is configured to adjust the bandwidth and transmittance peak of the transmission spectrum by changing at least one of the following: the material of each layer of the double-layer structure, the distance between two adjacent double-layer structures, and the material of the substrate layer.

9. The color filter according to claim 6, characterized in that, At least one filter unit includes a red filter unit, a green filter unit, and a blue filter unit, and each of the dual-layer structures is a cylinder; wherein, In the red filter unit, the distance between two adjacent double-layer structures is 273 nm to 313 nm, the diameter of each double-layer structure is 122 nm to 162 nm, the thickness of the metal layer in the first direction is 20 nm to 40 nm, the thickness of the second dielectric layer in the first direction is 200 nm to 240 nm, and the thickness of the portion of the transition layer corresponding to the red filter unit in the first direction is 20 nm to 40 nm. In the green filter unit, the distance between two adjacent double-layer structures is 320 nm to 360 nm, the diameter of each double-layer structure is 142 nm to 182 nm, the thickness of the metal layer in the first direction is 30 nm to 50 nm, the thickness of the second dielectric layer in the first direction is 225 nm to 265 nm, and the thickness of the transition layer corresponding to the red filter unit in the first direction is 45 nm to 65 nm. In the blue filter unit, the distance between two adjacent double-layer structures is 174 nm to 214 nm, the diameter of each double-layer structure is 75 nm to 100 nm, the thickness of the metal layer in the first direction is 45 nm to 65 nm, the thickness of the second dielectric layer in the first direction is 190 nm to 230 nm, and the thickness of the transition layer corresponding to the red filter unit in the first direction is 10 nm to 30 nm.

10. An image processing device, characterized in that, The image processing device includes a color filter as described in any one of claims 1-9.

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