Multispectral pixel structure and image sensor

Abstract

The invention discloses a multispectral pixel structure and an image sensor, the pixel structure comprises a pixel array, the pixel array comprises a plurality of modules arranged in an array, each module comprises M * N color filters and M * N micro lenses, and the transmission wavelength ranges and corresponding transmittances of part or all of the M * N color filters are different from each other; wherein one or more first wavelength color filters transmitting the first wavelength range exist in the M * N color filters, the transmittance of the first wavelength color filters is larger than that of the non-first wavelength color filters, and the area of the first wavelength color filters is smaller than that of the non-first wavelength color filters; and / or a plurality of Kth wavelength color filters transmitting the Kth wavelength range exist in the M * N color filters, the transmittance of the Kth wavelength color filters is smaller than that of the non-Kth wavelength color filters, the area of the Kth wavelength color filters is larger than that of the non-Kth wavelength color filters, M is larger than or equal to 2, N is larger than or equal to 2, and M and N are integers. Pixel structure design is carried out according to the transmittance condition of the color filters, color crosstalk can be reduced, the process manufacturing difficulty of the image sensor is reduced, the image sensor is particularly suitable for color temperature detection, and through the reasonable arrangement design of the multiple color filters, the color temperature detection with the wider warm and cold range and more real can be provided.

Description

Technical Field

[0001] The present invention relates to the field of image sensors, and in particular to a pixel structure and an image sensor. Background Art

[0002] The image sensor uses the photoelectric conversion function of the photoelectric devices in the pixel array to convert the light image on the photosensitive surface into an electrical signal that is proportional to the light image, and then records the image information through processing and storage by peripheral circuits.

[0003] Red green blue (RGB) imaging technology refers to collecting the red spectrum information, green spectrum information and blue spectrum information of the target object in the visible light spectrum band, and then generating an image of the target object. Hyperspectral imaging technology or multispectral imaging technology has more spectral bands, and can collect light signals of the target object in more spectral bands. It has the characteristics of high spectral resolution and wide spectral range, and the amount of information collected is richer. In order to present an image that is convenient for the human eye to watch, after collecting the spectral information of the target object through a hyperspectral or multispectral filter array, it is necessary to finally output an RGB image. Therefore, a solution that uses a hyperspectral or multispectral filter array to collect the light signal of the target object and is compatible with RGB imaging technology is urgently needed.

[0004] At present, chip-based multi-spectral Fabry-Perot interference filter devices mostly use physical methods, mainly including all-dielectric filters and metal interference filters. The latter adjusts the filter wavelength by changing the thickness of the medium in the metal layer, and has a low transmittance. Both filter designs use the principle of multi-beam interference filtering. When multi-spectral filtering is to be achieved, a specific film thickness or number of film layers needs to be selected for a specific wavelength, so it is necessary to prepare filter unit arrays with different film thicknesses on the same chip.

[0005] Existing multispectral chips generally have a pixel structure with periodically arranged color channels such as 3*3 or 4*4, and the channels involved are realized by covering the chip with color filter materials of different types or thicknesses. Color filter materials of different types or thicknesses have different transmittances, and generally one or more channels have higher transmittances and one or more channels have lower transmittances. There is a microlens structure above the color filter material to converge the incident light, improve sensitivity, and reduce crosstalk between different color channels. However, in the currently common multispectral chips, different color channels have basically the same area; and usually microlenses are arranged above all color channels, and the microlenses have the same critical dimensions; however, this may cause the pixel sensitivity in some high-transmittance channels (such as transparent (white) channels) to be too high, quickly reaching saturation, affecting the use of image sensors. In order to solve this problem, the prior art often removes the microlens above the color channel and only sets microlenses above other colors; however, at this time, although the pixel sensitivity of the high-transmittance channel is reduced and will not quickly reach saturation, the lack of a microlens structure will lead to new problems. First, without the microlens, the light of the color channel is not converged, causing it to propagate to the adjacent color channel and cause serious crosstalk; second, after some microlenses are removed, the microlenses in the microlens layer cannot be evenly adjacent to each other, which brings great difficulties to the manufacturing process of the microlens and greatly reduces the stability of the process. Summary of the invention

[0006] Based on the problems described above, the multi-spectral pixel structure and image sensor proposed in the present invention design the area of ​​color filters, microlenses and even photodiode sub-pixels based on the transmittance of each color filter, which can reduce color crosstalk, reduce the difficulty of process manufacturing of image sensors, and improve the color temperature effect of the sensor.

[0007] In a first aspect, the present invention provides a multi-spectral pixel structure, the pixel structure comprising a pixel array, a color filter array, and a microlens array, wherein the color filter array comprises: M*N color filters, wherein the transmission wavelength ranges and corresponding transmittances of some or all of the M*N color filters are different from each other; Among the M*N color filters, there are a plurality of first wavelength color filters transmitting the first wavelength range, the transmittance of the first wavelength color filters is greater than the transmittance of the non-first wavelength color filters, and the area of ​​the first wavelength color filters is smaller than the area of ​​the non-first wavelength color filters; and / or, Among the M*N color filters, there are several K-th wavelength color filters that transmit the K-th wavelength range, the transmittance of the K-th wavelength color filters is less than the transmittance of non-K-th wavelength color filters, and the area of ​​the K-th wavelength color filters is greater than the area of ​​non-K-th wavelength color filters; Among them, M≥2, N≥2, and M and N are integers.

[0008] Preferably, the M*N color filters are repeatedly arranged as a cycle. In one cycle, the color filters are grouped according to their respective transmittance ranges, and the groups are different to match the areas of different color filters, wherein the color filters in the group with relatively large transmittance are arranged adjacent to the color filters in the group with relatively small transmittance.

[0009] Preferably, the M*N color filters are repeatedly arranged as a cycle. In one cycle, except for the first wavelength filter, the remaining color filters are grouped according to their respective transmittance ranges, and the groups are different to match the areas of different color filters, wherein the color filters in the group with relatively large transmittance are arranged adjacent to the color filters in the group with relatively small transmittance.

[0010] Preferably, within one cycle, the positions of the first wavelength filter and the Kth wavelength filter are fixed, and the first wavelength filter and the Kth wavelength filter are arranged alternately adjacent to or non-adjacent to each other, and the remaining filters are arranged in sequence at positions outside the first wavelength filter and the Kth wavelength filter.

[0011] Preferably, within one period, each color filter in a group with relatively large transmittance is arranged adjacent to the Kth wavelength filter, and each color filter in a group with relatively small transmittance is arranged adjacent to the first wavelength filter as much as possible.

[0012] Preferably, when M is equal to N and M and N are odd numbers, at least one of the first wavelength filters is disposed corresponding to the photodiode sub-pixel at the center position in the M*N arrangement.

[0013] Preferably, the first wavelength filter includes a transparent filter and / or a yellow filter.

[0014] Preferably, the Kth wavelength filter comprises an infrared filter.

[0015] Preferably, M=N, M*N=9, and the transmission wavelength ranges of the respective color filters are different from each other, or the transmission wavelength ranges of the eight color filters are different from each other.

[0016] Preferably, the color filter array comprises the following 9 color filters respectively: A first wavelength color filter that transmits white in a first wavelength range; A second wavelength color filter that transmits yellow in a second wavelength range; A third wavelength color filter that transmits cyan in a third wavelength range; a fourth wavelength color filter transmitting a first magenta color in a fourth wavelength range; a fifth wavelength color filter transmitting a second magenta color in a fifth wavelength range; A sixth wavelength color filter that transmits green in a sixth wavelength range; A seventh wavelength color filter that transmits red in the seventh wavelength range; An eighth wavelength color filter that transmits blue in an eighth wavelength range; A ninth wavelength color filter that transmits infrared light in a ninth wavelength range; The fourth wavelength range and the fifth wavelength range are the same or different.

[0017] Preferably, the transmittance of the 1st wavelength filter to the 9th wavelength filter through their corresponding 1st wavelength to the 9th wavelength decreases sequentially, and the area of ​​the 1st wavelength filter to the 9th wavelength filter increases sequentially, wherein the sequential increase includes sequentially increasing one by one or sequentially increasing in groups, and the group is composed of several filters.

[0018] Preferably, in one cycle, the first wavelength filter is centrally arranged, and the sixth wavelength filter, the seventh wavelength filter, the eighth wavelength filter, and the ninth wavelength filter are adjacently arranged around it, and the first wavelength filter is not adjacent to the second wavelength filter, the third wavelength filter, the fourth wavelength filter, and the fifth wavelength filter.

[0019] Preferably, in one period, the sixth wavelength filter, the seventh wavelength filter, the eighth wavelength filter, and the ninth wavelength filter each cover a portion of the photodiode sub-pixel at the center and form sides adjacent to each other in pairs.

[0020] Preferably, the microlenses corresponding to the color filters having different transmission wavelength ranges have different heights.

[0021] Preferably, the microlenses corresponding to the color filters having different transmission wavelength ranges have different heights which differ by no more than 50%.

[0022] Preferably, the pixel structure further includes a grid structure, and the M*N color filters at least cover the openings of the grid.

[0023] Preferably, the grid is arranged in the same layer as the color filter, or the grid is arranged below the color filter.

[0024] Preferably, the effective area of ​​the color filter is adjusted by adjusting the size of the grid or the position of the grid relative to the photodiode sub-pixel to change the opening.

[0025] Preferably, the position and / or area of ​​each color filter within one period of the first region of the color filter array is different from the position and / or area of ​​each color filter within one period of the second region of the pixel array.

[0026] Preferably, the first area is located in a central area of ​​the pixel array, and the second area is located in a peripheral area of ​​the pixel array.

[0027] Preferably, from the central area of ​​the pixel array toward the peripheral area of ​​the pixel array, the color filters of the same color in different periods gradually change according to a preset rule.

[0028] Preferably, the preset rule includes that the positions of the color filters in different periods are the same, but from the central area of ​​the pixel array toward the peripheral area of ​​the pixel array, the same color filters in different periods gradually increase or decrease according to a preset ratio.

[0029] Preferably, the preset ratio is less than 10%.

[0030] Preferably, the microlens array comprises M*N microlenses, and the critical dimensions of the M*N microlenses are arranged on the M*N color filters in a one-to-one correspondence with the areas of the M*N color filters.

[0031] Preferably, the key sizes of the M*N microlenses are matched one-to-one with the areas of the M*N color filters. Specifically, a change in the key size or area of ​​a microlens is consistent with a change in the area of ​​the corresponding color filter within an error range.

[0032] Preferably, the error range is within ±30%.

[0033] Preferably, the pixel array comprises M*N photodiode sub-pixels located below the M*N color filters, and the M*N photodiode sub-pixels have the same size as each other.

[0034] In a second aspect, the present invention provides an image sensor, comprising a plurality of multi-spectral pixel structures as described in any one of the aforementioned embodiments.

[0035] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: the multi-spectral pixel structure and image sensor proposed in the present invention can reduce color crosstalk, reduce the difficulty of image sensor manufacturing process, and improve the color temperature effect of the sensor by designing the area through the transmission wavelength range of the color filter and the corresponding transmittance, and even design matching microlenses corresponding to the color filter. The multi-spectral pixel structure and image sensor proposed in the present invention are particularly suitable for color temperature detection, and can provide a wider and more realistic color temperature detection with a warmer or colder range through the reasonable arrangement and design of several color filters. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings of the present invention constitute a part of this specification and are used to further understand the present invention. The drawings illustrate embodiments of the present invention and together with the description are used to explain the principle of the present invention.

[0037] Figure 1 This is a multi-spectral pixel structure according to an embodiment of the present invention.

[0038] Figure 2 This is a multi-spectral module according to an embodiment of the present invention.

[0039] Figure 3 This is an example of a symmetric multi-spectral module according to a preferred embodiment of the present invention.

[0040] Figure 4a~4b This is an example of an asymmetric multi-spectral module according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following detailed descriptions are all illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0042] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention.

[0043] In a first aspect, an embodiment of the present invention proposes a multi-spectral pixel structure, wherein the pixel structure includes a pixel array, a color filter array, and a microlens array, wherein the color filter array includes M*N color filters, and the transmission wavelength ranges and corresponding transmittances of some or all of the M*N color filters are different from each other; wherein, among the M*N color filters, there are several first wavelength color filters that transmit the first wavelength range, the transmittance of the first wavelength color filter is greater than the transmittance of non-first wavelength color filters, and the area of ​​the first wavelength color filter is smaller than the area of ​​non-first wavelength color filters, M and N may be equal, M and N may also be unequal, and / or, among the M*N color filters, there are several Kth wavelength color filters that transmit the Kth wavelength range, the transmittance of the Kth wavelength color filter is less than the transmittance of non-Kth wavelength color filters, and the area of ​​the Kth wavelength color filter is larger than the area of ​​non-Kth wavelength color filters; wherein, M≥2, N≥2, and M and N are integers.

[0044] Preferably, the M*N microlenses have critical dimensions that match the area dimensions of the M*N color filters in a one-to-one correspondence and are arranged on the M*N color filters; further, the critical dimensions of the M*N microlenses match the area dimensions of the M*N color filters in a one-to-one correspondence, and the area dimensions of the color filters and the microlenses may change according to an equal change condition, or specifically, the change of the critical dimension or area of ​​the microlenses is consistent with the change of the area of ​​the corresponding color filters within an error range, for example, the error range is within ±30%.

[0045] The area changes of the color filters mentioned in the present invention are all changes in the effective area of ​​the color filters that can transmit light through the openings of the covering grid. The present invention sets the color filters with high transmittance to have a small area and matches all the color filters with microlenses, for example, sets the color filters with the highest transmittance to have the smallest area and matches all the color filters with microlenses. This can avoid the sub-pixels corresponding to the high transmittance color filters from reaching saturation quickly, prevent color crosstalk, reduce the difficulty of the manufacturing process, and greatly improve the color temperature effect of the sensor.

[0046] like Figure 1 FIG. 1 is an example of a multi-spectral pixel structure 0 (top view). The pixel structure 0 includes M*N color filters as a module 10 that is repeatedly arranged periodically. The module 10 includes a plurality of sub-pixel regions A corresponding to the plurality of sub-pixel regions. 11 , …, A MN M*N color filters 100 are provided, and M*N color filters are, for example, CF 11 , …, CF MN The module also includes a grid structure, which can be arranged in the same layer as the color filter or below the color filter, so that the M*N color filters can at least cover the corresponding multiple sub-pixel areas A of the grid one by one. 11 , …, A MN The embodiment provides a module 10 of an M*N array, but in other embodiments, the arrangement should not be limited to this. In this embodiment, the color filter CF 11 , …, CF MN The transmission wavelength ranges of some or all of the color filters are different from each other, and CF 11 , …, CF MN The transmittances of some or all of the color filters in the corresponding transmission wavelength ranges are different from each other. For example, the color filter CF 11 The corresponding transmission wavelength range is different from CF 12 Corresponding to its transmission wavelength range; color filter CF 11 The transmittance corresponding to its transmission wavelength range is different from CF 12The transmittance corresponding to its transmission wavelength range. It can be understood by those skilled in the art that a color filter can block some bands of light in the spectrum and allow light in other bands to pass through. Generally, a color filter that can transmit more than 50% of light in certain bands is considered to be a color filter with a transmission wavelength range of that band. For example, a red color filter is considered to be a color filter that transmits the red band. The transmittance mentioned in the present invention should be the transmittance of the color filter through its corresponding band. For example, the transmittance of a red color filter through the red band and the transmittance of a green color filter through the green band are not listed here one by one.

[0047] Preferably, each color filter CF 11 , …, CF MN Each microlens 300 is matched one by one. Figure 1 Not indicated, see Figure 2~3 ), each microlens 300 is named L 11 , …, L MN The critical dimensions of the N micro-lenses are matched one-to-one with the area dimensions of the N color filters and are arranged on the M*N color filters. Specifically, L 11 , …, L MN Can correspond to CF one by one 11 , …, CF MN For example, when the area of ​​the first wavelength filter is reduced, it is preferred to reduce the critical size of the microlens disposed thereon.

[0048] Figure 1 It is also illustrated that the module 10 further includes N photodiode sub-pixels 200 located under the M*N color filters, and the M*N photodiode sub-pixels have the same size as each other. Figure 1 As shown, it is a schematic diagram of the photodiode sub-pixel array included in the pixel structure 0, and multiple photodiode sub-pixel arrays correspond to multiple sub-pixel areas A in the module 10. 11 , …, A MN Set under M*N color filters 100, M*N photodiode sub-pixels 200, respectively P 11 ,…,P MN , and are also arranged in an M*N array. Although the attached figure illustrates an M*N array of photodiode sub-pixels, in a specific embodiment, the arrangement of photodiode sub-pixels should not be limited to this. Furthermore, the so-called M*N photodiode sub-pixels having the same size scale should mean that the area size of the M*N photodiode sub-pixels continues to use the existing unified standard scale and will not change with the change of the area of ​​the color filter mentioned in the above description. For example, when the area of ​​the first wavelength color filter is reduced by the first wavelength color filter, the photodiode sub-pixel matched thereunder is not designed to be reduced in area accordingly.

[0049] Preferably, M*N color filters are repeatedly arranged as a cycle, and in one cycle, each color filter is grouped according to its own transmittance range, and the areas of different color filters are matched according to different groups, wherein each color filter in a group with relatively large transmittance is arranged adjacent to each color filter in a group with relatively small transmittance. Further, in other preferred embodiments, in addition to setting the area of ​​the first wavelength color filter to be the smallest, the remaining color filters can also be matched one by one or partially one by one with different color filter areas according to their different transmittances; or the color filters in the preset transmittance range can be grouped into a group, and the color filters can be matched with different areas according to different grouping conditions.

[0050] By setting the color filter with relatively high transmittance (or preset transmittance range) to have a relatively small area, and the color filter with relatively low transmittance (or preset transmittance range) to have a relatively large area, and regardless of the size of the area of ​​the color filter, each color filter in the pixel structure is matched with a microlens in a corresponding area relationship, so that it is better to avoid the sub-pixel corresponding to the high transmittance color filter from reaching saturation quickly while preventing color crosstalk, and also avoid the difficulty of the manufacturing process caused by the uneven configuration of the microlens, thereby reducing the difficulty of the manufacturing process, and then greatly improving the color temperature effect of the sensor and reducing the manufacturing cost. Specifically, the relationship between the critical dimensions (CD) of each matching microlens is consistent with the relationship between the areas of each color filter. For example, the critical dimension (CD) of the first microlens set on the first wavelength color filter with the smallest area is smaller than the critical dimension (CD) of the microlens set on the non-first wavelength color filter.

[0051] In a preferred embodiment, the microlenses corresponding to the color filters with different transmission wavelength ranges have different heights. Preferably, the microlenses corresponding to the color filters with different transmission wavelength ranges have different heights with a difference of no more than 50%, which can facilitate the one-time production of the microlens layer while taking into account the adjustment of the beam control effect of each microlens. By controlling the height difference of the microlenses, the direction and amount of light transmission can be further controlled, thereby further improving the problems of crosstalk, rapid saturation of sub-pixels, and manufacturing process limitations.

[0052] In a specific embodiment, among the M*N color filters included in the module 10, there are several K-th wavelength color filters that transmit the K-th wavelength range, the transmittance of the K-th wavelength color filter is less than the transmittance of the non-K-th wavelength color filter, and the area of ​​the K-th wavelength color filter is larger than the area of ​​the non-K-th wavelength color filter, K≤M*N. That is, there are one or more color filters with the lowest transmittance, and their area can be set as large as possible, such as the maximum area, so that the saturation speed of its sub-pixel can be increased to improve the sensing efficiency.

[0053] In a preferred embodiment, in order to design an advantageous pixel structure at low cost and high efficiency as much as possible, within one cycle, the positions of the first wavelength filter and the Kth wavelength filter in the module are fixed, and the first wavelength filter and the Kth wavelength filter are arranged alternately adjacently or non-adjacently, and the remaining filters are arranged in sequence at positions other than the first wavelength filter and the Kth wavelength filter. The so-called sequential arrangement can be based on the size of the transmittance as the basis for the order, for example, the color filter with relatively large transmittance is arranged adjacent to the Kth wavelength filter as much as possible, and the color filter with relatively small transmittance is arranged adjacent to the first wavelength filter as much as possible; or each color filter with relatively large transmittance is arranged adjacent to other color filters with relatively small transmittance as much as possible. Although the embodiments of the present invention do not list various arrangements one by one, it can be understood that as long as the arrangement meets the above-mentioned arrangement purpose, it should be within the scope of the present invention.

[0054] The module 10 includes M*N photodiode sub-pixels 200 arranged in M*N. Further preferably, the first wavelength filter can be set corresponding to the photodiode sub-pixel at any position of the arrangement of the M*N photodiode sub-pixels; and in order to further improve the color temperature effect fed back by the pixel structure, preferably, when M and N are equal, and M and N are odd numbers, at least one first wavelength filter is set corresponding to the photodiode sub-pixel at the center position in the N*M arrangement, wherein, if there is only one first wavelength filter, it can be set above the middle photodiode sub-pixel to achieve the best symmetry; if there are five first wavelength filters, they can be set above the middle photodiode sub-pixel, which can also achieve the best symmetry. In some other arrangements, it may not be possible to obtain one or more photodiode sub-pixels in the center position. For example, when N*M is an even-numbered array of rows and columns or an arrangement with unequal numbers of rows and columns, it is difficult to obtain a photodiode sub-pixel in the center position at all angles, but at this time, a relatively center position can also be selected for arranging the first wavelength filter. It can be seen that by arranging the first wavelength filter on the photodiode sub-pixel in the middle area of ​​the module as much as possible, a better symmetry effect can be obtained, which can also make the symmetry of the entire module better and improve the image quality.

[0055] In a preferred embodiment, except for the first wavelength filter, the remaining color filters can be divided into several groups, and the areas of different color filters can be matched according to the groups. The color filters of the group with relatively large transmittance are arranged adjacent to the color filters of the group with relatively small transmittance. For example, the color filters of the group with relatively large transmittance are arranged adjacent to the Kth wavelength filter, and the color filters of the group with relatively small transmittance are arranged adjacent to the first wavelength filter as much as possible. For example, it is divided into a first group of color filters and a second group of color filters, wherein the transmittance of each color filter of the first group is greater than the transmittance of each color filter of the second group, so that the first wavelength filter can be designed to be adjacent to each color filter of the second group, and the first wavelength filter is not adjacent to each color filter of the first group, so as to improve crosstalk, rapid saturation of sub-pixels, manufacturing process limitations and other problems.

[0056] In a specific embodiment, for example Figure 2~3 As shown, the module 10 (10') further includes a grid structure 400, the opening size of the grid 400 matches the M*N color filters one by one, the grid 400 can be arranged in the same layer as the color filter 100 or arranged below the color filter 100, and the change of the color filter designed by the present invention can be adjusted by adjusting the size of the grid or the position relative to the photodiode sub-pixel to change the opening and thus adjust the effective area of ​​the color filter. It can be understood that the effective opening area of ​​each color filter 100 is equal to the opening area size of the corresponding grid 400.

[0057] In a specific embodiment, the design of the first wavelength filter of the present invention can be applied to a transparent (or white) filter and / or a yellow filter. The design of the Kth wavelength filter can be applied to an infrared filter.

[0058] As attached Figure 2 , is a preferred module example of the present invention, where M=N, M*N=9, and a 3*3 module 10 is used as an example, but in other embodiments, the present invention should not be limited to this. Further, each color filter CF is arranged in a 3*3 array 11 , …, CF 33 The transmission wavelength ranges of the 11 , …, CF 33 The transmission wavelength ranges of the eight color filters are different from each other (ie, there are two color filters having the same transmission wavelength range).

[0059] In a specific embodiment, the module 10 includes, for example, the following nine color filters 100 defined by the grid 400: 22 The first wavelength filter CF 22 , transmits white in the first wavelength range; located in sub-pixel area A 33 The second wavelength filter CF 33, transmits yellow in the second wavelength range; located in sub-pixel area A 32 The third wavelength filter CF 32 , transmits cyan in the third wavelength range; located in sub-pixel area A 31 The 4th wavelength color filter CF 31 , transmitting the first magenta color in the fourth wavelength range; located in sub-pixel area A 13 The fifth wavelength color filter CF 13 , transmitting the second magenta color in the fifth wavelength range; located in sub-pixel area A 12 The 6th wavelength color filter CF 11 , transmits green in the sixth wavelength range; located in sub-pixel area A 11 7th wavelength color filter CF 12 , transmits red in the seventh wavelength range; located in sub-pixel area A 21 8th wavelength color filter CF 21 , transmits blue in the eighth wavelength range; located in sub-pixel area A 23 9th wavelength color filter CF 23 , transmitting infrared light in the ninth wavelength range. The fourth wavelength range and the fifth wavelength range are the same or different, and the transmittance of the filter materials of the first wavelength filter to the ninth wavelength filter decreases in sequence. And the areas of the first wavelength filter to the ninth wavelength filter increase in sequence, wherein the sequential increase includes sequential increase one by one or sequential increase in groups, and the group is composed of a plurality of filters, such as attached Figure 3 The example is one of the preferred example of increasing in groups.

[0060] Exemplarily, the transmittance of the nine color filters 100 defined by the module 10 for the wavelength band 400-700 nm may be as follows: Green filter G: Transmittance at wavelengths of 475-610nm> 20%, especially at wavelengths of 505-590nm> 50%, and transmittance at other wavelengths < 20%; Blue filter B: The transmittance is >20% at a wavelength of about 400-520nm, especially >50% at a wavelength of 400-495nm, and <20% at other wavelengths; Red filter R: The transmittance is >20% at a wavelength of about 580-700nm, especially >50% at a wavelength of 585-700nm, and <20% at other wavelengths; Cyan filter C: Transmittance > 20% at wavelengths of about 400-555nm, especially > 50% at wavelengths of 400-540nm, and < 20% at other wavelengths; Yellow filter Y: The transmittance is >20% at a wavelength of about 480-700nm, especially >50% at a wavelength of 485-700nm, and <20% at other wavelengths; First magenta color filter M1: the transmittance is greater than 20% at wavelengths of about 400-490nm and 585-700nm, in particular, the transmittance is greater than 50% at wavelengths of 400-450nm and 595-700nm, and the transmittance is less than 20% at other wavelengths; Second magenta color filter M2: the transmittance is greater than 20% at wavelengths of about 400-510nm and 580-700nm, especially greater than 50% at wavelengths of 400-470nm and 590-700nm, and less than 20% at other wavelengths; Infrared filter IR: The transmittance is >20% for wavelengths above about 600nm, especially >50% for wavelengths greater than 785nm, and <20% for other wavelengths.

[0061] In a specific embodiment, the eight color filters except the first wavelength filter are grouped according to the transmittance range. For example, the second wavelength filter, the third wavelength filter, the fourth wavelength filter, and the fifth wavelength filter are classified as filters that meet the first transmittance range; the sixth wavelength filter, the seventh wavelength filter, the eighth wavelength filter, and the ninth wavelength filter are classified as filters that meet the second transmittance range.

[0062] To further improve the problems of crosstalk, rapid saturation of sub-pixels, and manufacturing process limitations, such as Figure 3 As shown, the module 10 'is illustrated, and the corresponding color filters CF ' 11 , …, CF´ 33 . The sixth wavelength filter, the seventh wavelength filter, the eighth wavelength filter, and the ninth wavelength filter are respectively arranged adjacent to the first wavelength filter, and the first wavelength filter is not adjacent to the second wavelength filter, the third wavelength filter, the fourth wavelength filter, and the fifth wavelength filter. It can be seen that relative Figure 2 The example arrangement, Figure 3 The instance of Figure 2 Sub-pixel area A in 11 , A 32 The color of the filter, in Figure 3 Located in sub-pixel area A 32 The 7th wavelength filter CF 11 (CF´ 32 ), transmits red in the seventh wavelength range; located in sub-pixel area A 11 The third color filter CF 32 (CF´ 11 ), transmits cyan in the third wavelength range. Preferably, as Figure 3 As shown, the sixth wavelength filter, the seventh wavelength filter, the eighth wavelength filter, and the ninth wavelength filter are also provided, each extending to cover a portion of the photodiode sub-pixel 200 at the central position and forming sides adjacent to each other in pairs, so that the transparent (white) first wavelength filter CF ' 22 The area can be reduced by reducing the first wavelength filter CF´ 22 The area of ​​the photodiode sub-pixel 200 under the transparent (white) first wavelength filter can be prevented from being too sensitive and quickly reaching saturation, which affects the use. Preferably, the sixth wavelength filter, the seventh wavelength filter, the eighth wavelength filter, and the ninth wavelength filter each extend to cover the area of ​​the photodiode sub-pixel 200 in the center and are centrally symmetrical, so that the symmetry of the entire module 10 can be better, and the image quality can be improved. For details, please refer to the attached Figure 3 The partial grid 400 originally arranged at the dotted line position shown in the figure is moved above the photodiode sub-pixel 200 in the center, and the 6th wavelength filter, the 7th wavelength filter, the 8th wavelength filter, and the 9th wavelength filter respectively form corresponding grids on the partial positions of the diagonal lines of the photodiode sub-pixel 200, so that the 6th wavelength filter, the 7th wavelength filter, the 8th wavelength filter, and the 9th wavelength filter form edges adjacent to each other.

[0063] Attached Figure 3 In the example, the sub-pixel area A 11 , …, A 33 , each microlens is exemplarily named L´ 11 , …, L´ 33 , microlens L´ 11 , …, L´ 33 Critical dimensions and color filter CF´ 11 , …, CF´ 33 The area sizes of the microlenses L' are matched one by one. 22 With the first critical dimension CD 1 , corresponding to the above grouping, microlens L´ 11 , L´ 13 , L´ 31 , …, L´ 33 With the second critical dimension CD 2 , microlens L´ 12 , L´ 23 , L´ 32 , …, L´ 23 With the third critical dimension CD 3 , the first critical dimension CD 1 <Second critical dimension CD 2 <The third critical dimension CD3 (Wherein, the CD size may be, for example, the major and minor axis size of the ellipsoidal lens at the contact surface between the microlens and the color filter, or the diameter of a perfect sphere.) In other optional embodiments, it is not limited to the following Figure 3 The CD relationship of the key dimensions of each microlens is shown. Each microlens can also be adjusted according to the actual adjustment of the area of ​​the color filter. In addition, in addition to adjusting the key dimension of the contact surface between the microlens and the color filter, the height of the microlens can also be adjusted (for example, the spherical microlens can adjust the ball height to adjust the light beam). In this embodiment, by matching each color filter with a microlens of a corresponding key dimension, it is possible to avoid the use of a method of removing the microlens to avoid the rapid saturation of the corresponding photodiode sub-pixel, thereby avoiding the huge process manufacturing difficulty and color crosstalk caused by the occasional missing microlens. By reducing the area of ​​the color filter, the pixels of the color filter with high transmittance can also be prevented from reaching saturation quickly, which can improve the color temperature effect of the sensor.

[0064] It should be pointed out that Figure 3 The exemplary embodiment of the module 10' has better symmetry among the embodiments, and can better balance the avoidance of rapid saturation of pixels of the high transmittance color filter, reduce color crosstalk, reduce the difficulty of manufacturing the image sensor, reduce cost, and improve the color temperature effect of the sensor. The embodiment of the present invention will not actually be based on Figure 3 For the purpose of limitation, as an example, the attached Figure 4a The diagram shows the first wavelength filter of the module 10'' with a reduced area and the ninth wavelength filter with an increased area. Figure 4a In the embodiment shown, only the sub-pixel area A 23 Color filter CF 23 spans adjacent photodiode sub-pixels P 23 , P 22 , the increased area of ​​the 9th wavelength filter covers the photodiode sub-pixel P 23 It also extends to the photodiode sub-pixel P 22 Attached Figure 4b Also shown is an example of a module 10''' including an asymmetric color filter, except for the sub-pixel region A in the module 10'''. 11 , A 13 Color filter CF 11 , CF 13 Except for the color filter CF, the rest of the color filters are not matched according to the boundaries defined by the photodiode sub-pixels (see the dotted lines in the figure). 21 , CF 32 , CF 23 Uneven squeezed color filter CF across the photodiode sub-pixel boundary towards the middle 22 Outside the area of ​​the color filter CF 12Also across the photodiode sub-pixel P 13 Squeeze Color Filter CF 13 The area of ​​the color filter CF 32 Also across the photodiode sub-pixel P 33 Squeeze Color Filter CF 33 The area of ​​each color filter can be precisely arranged to obtain the appropriate amount of incident light. The aforementioned symmetrical or asymmetrical arrangement of the areas of each color filter is only an example, and the present invention does not exhaustively list the specific practicable situations. It can be understood by those skilled in the art that other similar arrangements of color filters should also be within the scope of the present invention.

[0065] Preferably, the position and / or area of ​​the color filters of the module in the first area of ​​the pixel array of the image sensor is different from the position and / or area of ​​each color filter of the module in the second area of ​​the pixel array. In other words, the different arrangements of the color filters include one or more differences in the position and area of ​​the color filters in the module. Preferably, the first area can be arranged in the middle area of ​​the pixel array, and the second area can be arranged in the peripheral area of ​​the pixel array, so as to design the module to match the difference in the amount of light and the angle of light incident in the middle area and the edge area.

[0066] Preferably, from the central area of ​​the pixel array toward the peripheral area of ​​the pixel array, the color filters of the same color in different modules can gradually change according to a preset rule to adapt to the differences in the amount of light, incident angle, etc. between the central area and the peripheral area. For example, the preset rule may include that the positions of the color filters in different modules are the same, but from the central area of ​​the pixel array toward the peripheral area of ​​the pixel array, the color filters of the same color in different modules gradually increase or decrease according to a preset ratio, and the preset ratio may be, for example, less than 10%.

[0067] In a second aspect, the present invention provides an image sensor, which is designed to include a multi-spectral pixel structure of any of the aforementioned embodiments, and the details are not repeated here.

[0068] In summary, the multi-spectral pixel structure and image sensor proposed in the present invention can reduce color crosstalk, reduce the difficulty of image sensor manufacturing process, and improve the color temperature effect of the sensor by designing the pixel structure according to the transmittance of the color filter. The multi-spectral pixel structure and image sensor proposed in the present invention are particularly suitable for color temperature detection. Through the reasonable arrangement and design of several color filters, a wider and more realistic color temperature detection with a warmer or colder range can be provided.

[0069] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present invention. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and corrections to the present invention. Such modifications, improvements and corrections are suggested in the present invention, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of the present invention.

[0070] It should be understood that the embodiments described in the present invention are only used to illustrate the principles of the embodiments of the present invention. Other variations may also fall within the scope of the present invention. Therefore, as examples and not limitations, alternative configurations of the embodiments of the present invention may be considered consistent with the teachings of the present invention. Accordingly, the embodiments of the present invention are not limited to the embodiments explicitly introduced and described in the present invention.

Claims

1. A multi-spectral pixel structure, comprising a pixel array, a color filter array, and a microlens array, characterized in that: The color filter array comprises, M*N color filters, wherein the transmission wavelength ranges and corresponding transmittances of some or all of the M*N color filters are different from each other; Among the M*N color filters, there are a plurality of first wavelength color filters transmitting the first wavelength range, the transmittance of the first wavelength color filters is greater than the transmittance of the non-first wavelength color filters, and the area of ​​the first wavelength color filters is smaller than the area of ​​the non-first wavelength color filters; and / or, Among the M*N color filters, there are several K-th wavelength color filters that transmit the K-th wavelength range, the transmittance of the K-th wavelength color filters is less than the transmittance of non-K-th wavelength color filters, and the area of ​​the K-th wavelength color filters is greater than the area of ​​non-K-th wavelength color filters; Among them, M≥2, N≥2, and M and N are integers.

2. The multi-spectral pixel structure according to claim 1, characterized in that: The M*N color filters are repeatedly arranged as a cycle. In one cycle, the color filters are grouped according to their respective transmittance ranges, and the groups are different to match the areas of different color filters, wherein the color filters in the group with relatively large transmittance are arranged adjacent to the color filters in the group with relatively small transmittance.

3. The multi-spectral pixel structure according to claim 1, characterized in that: The M*N color filters are repeatedly arranged as a cycle. In one cycle, except for the first wavelength filter, the other color filters are grouped according to their respective transmittance ranges, and the groups are different to match the areas of different color filters, wherein the color filters in the group with relatively large transmittance are arranged adjacent to the color filters in the group with relatively small transmittance.

4. The multi-spectral pixel structure according to claim 2 or 3, characterized in that: In one cycle, the positions of the first wavelength filter and the Kth wavelength filter are fixed, and the first wavelength filter and the Kth wavelength filter are arranged alternately adjacent to or non-adjacent to each other, and the remaining filters are arranged in sequence at positions outside the first wavelength filter and the Kth wavelength filter.

5. The multi-spectral pixel structure according to claim 2 or 3, characterized in that: In one period, each color filter of the group with relatively large transmittance is arranged adjacent to the Kth wavelength filter, and each color filter of the group with relatively small transmittance is arranged adjacent to the 1st wavelength filter as much as possible.

6. The multi-spectral pixel structure according to claim 1, characterized in that: When M is equal to N and M and N are odd numbers, at least one of the first wavelength filters is disposed corresponding to the photodiode sub-pixel at the center position in the M*N arrangement.

7. The multi-spectral pixel structure according to any one of claims 1 to 6, characterized in that: The first wavelength filter includes a transparent filter and / or a yellow filter.

8. The multi-spectral pixel structure according to any one of claims 1 to 7, characterized in that: The Kth wavelength filter includes an infrared filter.

9. The multi-spectral pixel structure according to any one of claims 1 to 8, characterized in that: M=N, M*N=9, and the transmission wavelength ranges of the respective color filters are different from each other, or the transmission wavelength ranges of the eight color filters are different from each other.

10. The multi-spectral pixel structure according to claim 9, characterized in that: The color filter array includes the following 9 color filters: A first wavelength color filter that transmits white in a first wavelength range; A second wavelength color filter that transmits yellow in a second wavelength range; A third wavelength color filter that transmits cyan in a third wavelength range; a fourth wavelength color filter transmitting a first magenta color in a fourth wavelength range; a fifth wavelength color filter transmitting a second magenta color in a fifth wavelength range; A sixth wavelength color filter that transmits green in a sixth wavelength range; A seventh wavelength color filter that transmits red in the seventh wavelength range; An eighth wavelength color filter that transmits blue in an eighth wavelength range; A ninth wavelength color filter that transmits infrared light in a ninth wavelength range; The fourth wavelength range and the fifth wavelength range are the same or different.

11. The multi-spectral pixel structure according to claim 10, characterized in that: The transmittance of the 1st wavelength filter to the 9th wavelength filter through its corresponding 1st wavelength to the 9th wavelength decreases sequentially, and the area of ​​the 1st wavelength filter to the 9th wavelength filter increases sequentially, wherein the sequential increase includes sequentially increasing one by one or sequentially increasing in groups, and the group is composed of a number of filters.

12. The multi-spectral pixel structure according to claim 10 or 11, characterized in that: In one cycle, the first wavelength filter is centrally arranged, and the sixth wavelength filter, the seventh wavelength filter, the eighth wavelength filter, and the ninth wavelength filter are adjacently arranged around it, and the first wavelength filter is not adjacent to the second wavelength filter, the third wavelength filter, the fourth wavelength filter, and the fifth wavelength filter.

13. The multi-spectral pixel structure according to claim 12, characterized in that: In one period, the sixth wavelength filter, the seventh wavelength filter, the eighth wavelength filter, and the ninth wavelength filter each cover a portion of the photodiode sub-pixel at the center and form sides adjacent to each other in pairs.

14. The multi-spectral pixel structure according to claims 1 to 13, characterized in that: The microlenses corresponding to the color filters having different transmission wavelength ranges have different heights.

15. The multi-spectral pixel structure according to claim 14, characterized in that: The microlenses corresponding to the color filters having different transmission wavelength ranges have different heights which differ by no more than 50%.

16. The multi-spectral pixel structure according to claim 1, characterized in that: The pixel structure further includes a grid structure, and M*N color filters at least cover the openings of the grid.

17. The multi-spectral pixel structure according to claim 16, wherein: The grid is arranged in the same layer as the color filter, or the grid is arranged below the color filter.

18. The multi-spectral pixel structure according to claim 16, wherein: The effective area of ​​the color filter can be adjusted by adjusting the size of the grid or the position relative to the photodiode sub-pixel to change the opening.

19. The multi-spectral pixel structure according to claim 1, characterized in that: The position and / or area of ​​each color filter within one period of the first region of the color filter array is different from the position and / or area of ​​each color filter within one period of the second region of the pixel array.

20. The multi-spectral pixel structure according to claim 19, characterized in that: The first area is located in the central area of ​​the pixel array, and the second area is located in the peripheral area of ​​the pixel array.

21. The multi-spectral pixel structure according to claim 19, characterized in that: From the central area of ​​the pixel array toward the peripheral area of ​​the pixel array, the color filters of the same color in different periods gradually change according to a preset rule.

22. The multi-spectral pixel structure according to claim 21, characterized in that: The preset rule includes that the color filters in different periods are arranged at the same position, but the color filters of the same color in different periods gradually increase or decrease according to a preset ratio from the central area of ​​the pixel array toward the peripheral area of ​​the pixel array.

23. The multi-spectral pixel structure according to claim 22, characterized in that: The preset ratio is less than 10%.

24. The multi-spectral pixel structure according to claim 1, characterized in that: The microlens array includes M*N microlenses, and the critical sizes of the M*N microlenses are matched one-to-one with the areas of the M*N color filters and are arranged on the M*N color filters.

25. The multi-spectral pixel structure according to claim 24, characterized in that: The key sizes of the M*N microlenses are matched one-to-one with the areas of the M*N color filters. Specifically, a change in the key size or area of ​​the microlens is consistent with a change in the area of ​​the corresponding color filter within an error range.

26. The multi-spectral pixel structure according to claim 25, characterized in that: The error range is within ±30%.

27. The multi-spectral pixel structure of claim 1, wherein: The pixel array includes M*N photodiode sub-pixels located under the M*N color filters, and the M*N photodiode sub-pixels have the same size as each other.

28. An image sensor, characterized in that: The invention comprises a multi-spectral pixel structure as described in any one of claims 1 to 27.

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