Color filter element

Abstract

The invention relates to a color filter element, which is used for being arranged on a photosensitive side of a CIS detector, and comprises a waveguide substrate which is provided with a plurality of first pixel regions, a plurality of second pixel regions and a plurality of third pixel regions which are periodically arranged; a plurality of first grating groups, wherein the first grating groups are arranged in the first pixel area; a plurality of second grating groups, wherein the second grating groups are arranged in the second pixel area; the third grating groups are arranged in the third pixel areas, and light beams filtered by other pixel areas are guided to a detection area of the CIS detector corresponding to the pixel area capable of penetrating through the corresponding wave band by utilizing the grating groups, so that more light energy of the wave band can be absorbed by the CIS detector, the light energy use efficiency of the CIS detector is improved, and the light efficiency of the CIS detector is improved. Therefore, the sensitivity and the detection quality of the CIS detector are improved.

Description

Technical Field

[0001] The invention relates to the technical field of optical elements, and in particular to a color filter element. Background Art

[0002] CMOS image sensor (Complementary Metal-Oxide-Semiconductor Image Sensor, CIS) is composed of many photosensitive units, namely pixels, each of which can convert incident photons into electronic charges. When light shines on the surface of the CIS detector, the semiconductor material can absorb the energy of the photons and generate electron-hole pairs, where the electrons are collected in the capacitor of the pixel, forming a charge accumulation proportional to the light intensity. By processing the above electrical signals, an image that can be recorded and displayed can be formed.

[0003] In order to realize color perception of CIS detector, a layer of color filter, namely color filter array (CFA), is usually covered on the CIS detector corresponding to each pixel. Common color filter arrays include Bayer arrays, which are composed of red (R), green (G), and blue (B) filters arranged in a certain pattern. The principle of CIS detector recording color images is as follows: light of different colors will be filtered by filters of corresponding colors, and only photons of specific colors can reach the corresponding pixels, so that each pixel responds to light of a specific color. For example, by adding corresponding R, G, and B filters in front of R, G, and B pixels, the filters can effectively intercept light of other bands, so that the CIS detector can record color images.

[0004] Since the filter only allows light of specific wavelengths to pass through and can reflect other wavelengths, the filter will filter out a large amount of light energy, so a large amount of light cannot be received by the CIS detector, resulting in a decrease in the efficiency of light energy use. In the Bayer array, only a quarter of the energy of light in the R and B bands can be detected, and only half of the energy of light in the G band can be detected, resulting in a significant reduction in the sensitivity of the CIS detector and an increase in noise in low-light environments. Summary of the invention

[0005] Based on this, it is necessary to provide a color filter element to address the problem of low light energy utilization efficiency in the color perception scheme of the existing CIS detector.

[0006] A color filter element, used for being arranged on the photosensitive side of a CIS detector, comprising:

[0007] A waveguide substrate, wherein the waveguide substrate has a plurality of first pixel areas, a plurality of second pixel areas, and a plurality of third pixel areas that are periodically arranged, wherein the first pixel areas are used to correspond to a first CIS detector that detects light of a first wavelength band, the second pixel areas are used to correspond to a second CIS detector that detects light of a second wavelength band, and the third pixel areas are used to correspond to a third CIS detector that detects light of a third wavelength band;

[0008] a plurality of first grating groups, wherein the first grating groups are arranged in the first pixel area, and are used to transmit the first wavelength band light in the first pixel area to the first CIS detector, and transmit the second wavelength band light in the first pixel area to the second pixel area and / or transmit the third wavelength band light in the first pixel area to the third pixel area;

[0009] a plurality of second grating groups, wherein the second grating groups are arranged in the second pixel area, and are used to transmit the second wavelength band light in the second pixel area to the second CIS detector, and transmit the first wavelength band light in the second pixel area to the first pixel area and / or transmit the third wavelength band light in the second pixel area to the third pixel area; and

[0010] A plurality of third grating groups are arranged in the third pixel area, and are used to transmit the third-band light in the third pixel area to the third CIS detector, and transmit the first-band light in the third pixel area to the first pixel area and / or transmit the second-band light in the third pixel area to the second pixel area.

[0011] In some embodiments, the first grating group includes a first front coupling-in grating disposed on the front surface of the waveguide substrate, a first rear coupling-in grating disposed on the rear surface of the waveguide substrate, a first front coupling-out grating disposed on the front surface of the waveguide substrate, and a first rear coupling-out grating disposed on the rear surface of the waveguide substrate; the second grating group includes a second front coupling-in grating disposed on the front surface of the waveguide substrate, a second rear coupling-in grating disposed on the rear surface of the waveguide substrate, a second front coupling-out grating disposed on the front surface of the waveguide substrate, and a second rear coupling-out grating disposed on the rear surface of the waveguide substrate; the third grating group includes a first front coupling-in grating disposed on the front surface of the waveguide substrate, a second rear coupling-in grating disposed on the rear surface of the waveguide substrate, a second front coupling-out grating disposed on the front surface of the waveguide substrate, and a second rear coupling-out grating disposed on the rear surface of the waveguide substrate; A third front coupling-in grating arranged on the front surface of the bottom, a third rear coupling-in grating arranged on the rear surface of the waveguide substrate, a third front coupling-out grating arranged on the front surface of the waveguide substrate, and a third rear coupling-out grating arranged on the rear surface of the waveguide substrate, wherein the first front coupling-in grating, the first rear coupling-out grating, the second front coupling-in grating, the second rear coupling-out grating, the third front coupling-in grating and the third rear coupling-out grating are all transmission gratings; the first rear coupling-in grating, the first front coupling-out grating, the second rear coupling-in grating, the second front coupling-out grating, the third rear coupling-in grating and the third front coupling-out grating are all reflection gratings.

[0012] In some embodiments, the first front coupling-in grating is arranged around the first front coupling-out grating, and the first rear coupling-in grating is arranged around the first rear coupling-out grating; the second front coupling-in grating is arranged around the second front coupling-out grating, and the second rear coupling-in grating is arranged around the second rear coupling-out grating; the third front coupling-in grating is arranged around the third front coupling-out grating, and the third rear coupling-in grating is arranged around the third rear coupling-out grating.

[0013] In some embodiments, the area of ​​the first front coupling-in grating is larger than the first front coupling-out grating, and the area of ​​the first rear coupling-in grating is larger than the first rear coupling-out grating; the area of ​​the second front coupling-in grating is larger than the second front coupling-out grating, and the area of ​​the second rear coupling-in grating is larger than the second rear coupling-out grating; the area of ​​the third front coupling-in grating is larger than the third front coupling-out grating, and the area of ​​the third rear coupling-in grating is larger than the third rear coupling-out grating.

[0014] In some embodiments, the first front coupling grating, the first rear coupling grating, the second front coupling grating, the second rear coupling grating, the third front coupling grating and the third rear coupling grating all have positive optical power.

[0015] In some embodiments, the first front outcoupling grating, the first rear outcoupling grating, the second front outcoupling grating, the second rear outcoupling grating, the third front outcoupling grating and the third rear outcoupling grating all have negative optical power.

[0016] In some embodiments, the first grating group includes a first front diffraction grating disposed on the front surface of the waveguide substrate and / or a first rear diffraction grating disposed on the rear surface of the waveguide substrate; the second grating group includes a second front diffraction grating disposed on the front surface of the waveguide substrate and / or a second rear diffraction grating disposed on the rear surface of the waveguide substrate; the third grating group includes a third front diffraction grating disposed on the front surface of the waveguide substrate and / or a third rear diffraction grating disposed on the rear surface of the waveguide substrate.

[0017] In some embodiments, the first front diffraction grating includes two first front diffraction sub-gratings with grating vector directions perpendicular to each other, or the first rear diffraction grating includes two first rear diffraction sub-gratings with grating vector directions perpendicular to each other, the second front diffraction grating includes two second front diffraction sub-gratings with grating vector directions perpendicular to each other, or the second rear diffraction grating includes two second rear diffraction sub-gratings with grating vector directions perpendicular to each other, the third front diffraction grating includes two third front diffraction sub-gratings with grating vector directions perpendicular to each other, or the third rear diffraction grating includes two third rear diffraction sub-gratings with grating vector directions perpendicular to each other.

[0018] In some embodiments, the waveguide substrate has a thickness ranging from 0.3 mm to 3 mm.

[0019] In some embodiments, the air gap between the rear surface of the waveguide substrate and the CIS detector ranges from 1 μm to 1 mm.

[0020] The color filter element of the present application utilizes a grating group to transmit the second-band light in the first pixel area to the second pixel area or the third-band light in the first pixel area to the third pixel area, to transmit the first-band light in the second pixel area to the first pixel area or the third-band light in the second pixel area to the third pixel area, to transmit the first-band light in the third pixel area to the first pixel area or the second-band light in the third pixel area to the second pixel area, so that more first-band light is absorbed by the first CIS detector, more second-band light is absorbed by the second CIS detector, and more third-band light is absorbed by the third CIS detector, thereby improving the light energy utilization efficiency of the CIS detector and thus improving the sensitivity and detection quality of the CIS detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the front surface of the color filter element provided in the first embodiment of the present application;

[0022] Figure 2 A schematic diagram showing the rear surface of the color filter element according to the first embodiment of the present application is shown;

[0023] Figure 3 It shows that Figure 1 A schematic cross-sectional view of the color filter element along line X1-X1 shown;

[0024] Figure 4 A schematic diagram of the front surface of the color filter element provided in the second embodiment of the present application;

[0025] Figure 5 A schematic diagram showing the rear surface of the color filter element according to the second embodiment of the present application is shown;

[0026] Figure 6 It shows that Figure 4 A schematic cross-sectional view of the color filter element shown along X2-X2;

[0027] Figure 7 A schematic diagram of the front surface of the color filter element provided in the third embodiment of the present application;

[0028] Figure 8 It shows that Figure 7 The cross-sectional schematic diagram of the color filter element along X3-X3 is shown.

[0029] Figure 1: 10, waveguide substrate; 11, first pixel region; 12, second pixel region; 13, third pixel region; 20, first grating group; 21, first front coupling grating; 22, first rear coupling grating; 23, first front outcoupling grating; 24, first rear outcoupling grating; 25, first front diffraction grating; 26, first rear diffraction grating; 30, second grating group; 31, second front coupling grating; 32, second rear coupling grating; 33, second front outcoupling grating Grating; 34, second rear out-coupling grating; 35, second front diffraction grating; 36, second rear diffraction grating; 40, third grating group; 41, third front input grating; 42, third rear input grating; 43, third front out-coupling grating; 44, third rear out-coupling grating; 45, third front diffraction grating; 46, third rear diffraction grating; 50, CIS detector; 51, first CIS detector; 52, second CIS detector; 53, third CIS detector. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0033] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0036] Based on the problem that the color perception scheme of the existing CIS detector has low light energy utilization efficiency, a color filter element is provided. The color filter element is used to be arranged on the photosensitive side of the CIS detector, and can use the grating light waveguide technology to guide the light beam filtered by other pixel areas to the detection area of ​​the CIS detector corresponding to the pixel area that can transmit the corresponding band, so that more light energy in the band can be absorbed by the CIS detector, thereby improving the light energy utilization efficiency of the CIS detector, thereby improving the sensitivity and detection quality of the CIS detector.

[0037] For details, please refer to Figure 1 , Figure 2 and Figure 3 The color filter element of the present application may include a waveguide substrate 10, a plurality of first grating groups 20, a plurality of second grating groups 30, and a plurality of third grating groups 40. The waveguide substrate 10 is periodically provided with a plurality of first pixel areas 11, a plurality of second pixel areas 12, and a plurality of third pixel areas 13. The first pixel area 11 is used to correspond to a first CIS detector 51 for detecting light of a first wavelength band, the second pixel area 12 is used to correspond to a second CIS detector 52 for detecting light of a second wavelength band, and the third pixel area 13 is used to correspond to a third CIS detector 53 for detecting light of a third wavelength band. The first grating group 20 is arranged in the first pixel area 11, and is used to transmit the first wavelength band light in the first pixel area 11 to the first CIS detector 51, and transmit the second wavelength band light in the first pixel area 11 to the second pixel area 12 and / or transmit the third wavelength band light in the first pixel area 11 to the third pixel area 13. The second grating group 30 is disposed in the second pixel area 12, and is used to transmit the second-band light in the second pixel area 12 to the second CIS detector 52, and transmit the first-band light in the second pixel area 12 to the first pixel area 11 and / or transmit the third-band light in the second pixel area 12 to the third pixel area 13. The third grating group 40 is disposed in the third pixel area 13, and is used to transmit the third-band light in the third pixel area 13 to the third CIS detector 53, and transmit the first-band light in the third pixel area 13 to the first pixel area 11 and / or transmit the second-band light in the third pixel area 13 to the second pixel area 12.

[0038] It can be understood that when the light beam is irradiated to the first pixel area 11 of the waveguide substrate 10, the first band light in the light beam can directly pass through the first pixel area 11 and be recognized by the first CIS detector 51, while other bands of light in the light beam, for example, the second band light can be transmitted by the first grating group 20 to the second pixel area 12, emitted from the second pixel area 12 or transmitted by the second grating group 30 to the second CIS detector 52, and the third band light can be transmitted by the first grating group 20 to the third pixel area 13, emitted from the third pixel area 13 to the CIS detector 50 or transmitted by the third grating group 40 to the third CIS detector 53.

[0039] Similarly, when the light beam is irradiated to the second pixel area 12 of the waveguide substrate 10, the second band light in the light beam can directly pass through the second pixel area 12 and be recognized by the second CIS detector 52, while other bands of light in the light beam, for example, the first band light can be transmitted to the first pixel area 11 by the second grating group 30, emitted from the first pixel area 11 or transmitted to the first CIS detector 51 by the first grating group 20, and the third band light can be transmitted to the third pixel area 13 by the first grating group 20, emitted from the third pixel area 13 to the CIS detector 50 or transmitted to the third CIS detector 53 by the third grating group 40.

[0040] When the light beam is irradiated to the third pixel area 13 of the waveguide substrate 10, the third band light in the light beam can directly pass through the third pixel area 13 and be recognized by the third CIS detector 53, while other band lights in the light beam, for example, the first band light can be transmitted to the first pixel area 11 by the third grating group 40, emitted from the first pixel area 11 or transmitted to the first CIS detector 51 by the first grating group 20, and the second band light can be transmitted to the second pixel area 12 by the third grating group 40, emitted from the second pixel area 12 to the CIS detector 50 or transmitted to the second CIS detector 52 by the second grating group 30.

[0041] In this way, by utilizing the grating group to transmit the second-band light in the first pixel area 11 to the second pixel area 12 or to transmit the third-band light in the first pixel area 11 to the third pixel area 13, to transmit the first-band light in the second pixel area 12 to the first pixel area 11 or to transmit the third-band light in the second pixel area 12 to the third pixel area 13, to transmit the first-band light in the third pixel area 13 to the first pixel area 11 or to transmit the second-band light in the third pixel area 13 to the second pixel area 12, more first-band light is absorbed by the first CIS detector 51, more second-band light is absorbed by the second CIS detector 52, and more third-band light is absorbed by the third CIS detector 53, the light energy utilization efficiency of the CIS detector 50 can be improved, thereby improving the sensitivity and detection quality of the CIS detector 50.

[0042] like Figure 3 and Figure 6 As shown, in some embodiments, the first grating group 20 includes a first front coupling grating 21, a first rear coupling grating 24, a first front coupling grating 23 and a first rear coupling grating 24, the first front coupling grating 21 is arranged on the front surface of the waveguide substrate 10; the first rear coupling grating 22 is arranged on the rear surface of the waveguide substrate 10; the first front coupling grating 23 is arranged on the front surface of the waveguide substrate 10; the first rear coupling grating 24 is arranged on the front surface of the waveguide substrate The second grating group 30 includes a second front coupling grating 31, a second rear coupling grating 34, a second front coupling grating 33 and a second rear coupling grating 34, wherein the second front coupling grating 31 is arranged on the front surface of the waveguide substrate 10; the second rear coupling grating 32 is arranged on the rear surface of the waveguide substrate 10; the second front coupling grating 33 is arranged on the front surface of the waveguide substrate 10; the second rear coupling grating 34 is arranged on the waveguide substrate 10 The third grating group 40 includes a third front coupling grating 41, a third rear coupling grating 44, a third front coupling grating 43 and a third rear coupling grating 44, wherein the third front coupling grating 41 is arranged on the front surface of the waveguide substrate 10; the third rear coupling grating 42 is arranged on the rear surface of the waveguide substrate 10; the third front coupling grating 43 is arranged on the front surface of the waveguide substrate 10; the third rear coupling grating 44 is arranged on the rear surface of the waveguide substrate 10 surface; wherein the first front coupling-in grating 21, the first rear coupling-out grating 24, the second front coupling-in grating 31, the second rear coupling-out grating 34, the third front coupling-in grating 41 and the third rear coupling-out grating 44 are all transmission gratings; the first rear coupling-in grating 22, the first front outcoupling grating 23, the second rear coupling-in grating 32, the second front outcoupling grating 33, the third rear coupling-in grating 42 and the third front outcoupling grating 43 are all reflection gratings.

[0043] It can be understood that the first front coupling grating 21, the first rear coupling grating 22, the second front coupling grating 31, the second rear coupling grating 32, the third front coupling grating 41 and the third rear coupling grating 42 can be one-dimensional gratings or two-dimensional gratings. That is, the first front coupling grating 21 and the first rear coupling grating 22 can be used to couple in one of the second wavelength band light or the third wavelength band light, or can be used to couple in both the second wavelength band light and the third wavelength band light at the same time, and the first front coupling grating 23 and the first rear coupling grating 24 can be used to couple out the first wavelength band light. The second front coupling grating 31 and the second rear coupling grating 32 can be used to couple in one of the first wavelength band light or the third wavelength band light, or can be used to couple in both the first wavelength band light and the third wavelength band light at the same time, and the second front coupling grating 33 and the second rear coupling grating 34 can be used to couple out the second wavelength band light. The third front coupling-in grating 41 and the third rear coupling-in grating 42 can be used to couple in one of the first wavelength band light or the second wavelength band light, and can also be used to couple in both the first wavelength band light and the second wavelength band light at the same time. The third front coupling-out grating 43 and the third rear coupling-out grating 44 can be used to couple out the third wavelength band light.

[0044] Taking the first pixel area 11 as an example, when the light beam is irradiated to the first pixel area 11 of the waveguide substrate 10, the first band light in the light beam can directly pass through the first pixel area 11 and be recognized by the first CIS detector 51, while other band light in the light beam, for example, the second band light can be coupled into the waveguide substrate 10 by the first front coupling grating 21, transmitted to the second pixel area 12 through multiple reflections of the waveguide, and coupled out to the second CIS detector 52 by the second front coupling grating 33 or the second rear coupling grating 34 in the second pixel area 12, and the third band light can be coupled into the waveguide substrate 10 by the first front coupling grating 21, transmitted to the third pixel area 13 through multiple reflections of the waveguide, and coupled out to the third CIS detector 53 by the third front coupling grating 43 or the third rear coupling grating 44 in the third pixel area 13. Similarly, when the light beam irradiates the second pixel region 12 or the third pixel region 13 of the waveguide substrate 10 , the first wavelength band light, the second wavelength band light and the third wavelength band light in the light beam can also be coupled out to the corresponding CIS detector 50 .

[0045] like Figure 1 , Figure 2 , Figure 4 and Figure 5As shown, in some embodiments, the first front coupling-in grating 21 is arranged around the first front decoupling grating 23, and the first rear coupling-in grating 22 is arranged around the first rear decoupling grating 24; the second front coupling-in grating 31 is arranged around the second front decoupling grating 33, and the second rear coupling-in grating 32 is arranged around the second rear decoupling grating 34; the third front coupling-in grating 41 is arranged around the third front decoupling grating 43, and the third rear coupling-in grating 42 is arranged around the third rear decoupling grating 44.

[0046] In this way, by surrounding the coupling-in grating outside the coupling-out grating, more light beams coupled into the waveguide through the coupling-in grating can be converged to the coupling-out grating, reducing the loss of light energy and further improving the efficiency of light energy use.

[0047] In order to reduce the diffraction effect of the incident light beam in each pixel area of ​​the waveguide substrate 10 with the outcoupling grating when entering the waveguide, and then transmit the light to other pixel areas, the area of ​​the first front coupling grating 21 is larger than the first front coupling grating 23, and the area of ​​the first rear coupling grating 22 is larger than the first rear coupling grating 24; the area of ​​the second front coupling grating 31 is larger than the second front coupling grating 33, and the area of ​​the second rear coupling grating 32 is larger than the second rear coupling grating 34; the area of ​​the third front coupling grating 41 is larger than the third front coupling grating 43, and the area of ​​the third rear coupling grating 42 is larger than the third rear coupling grating 44. In this way, by setting the area of ​​the coupling grating to be larger than the area of ​​the outcoupling grating, it is possible to avoid the incident light from diffracting with the outcoupling grating, reduce unnecessary light energy loss, and improve the use efficiency of light energy.

[0048] It is worth noting that the area of ​​the coupling-in grating in the pixel region is generally slightly smaller than the area of ​​the pixel region, and the area of ​​the coupling-out grating in the pixel region is generally not greater than one quarter of the area of ​​the pixel region.

[0049] Since the area of ​​the coupling-in grating is larger than that of the coupling-out grating, in order to allow more light to be converged to the coupling-out grating, in some embodiments, the first front coupling-in grating 21, the first rear coupling-in grating 22, the second front coupling-in grating 31, the second rear coupling-in grating 32, the third front coupling-in grating 41, and the third rear coupling-in grating 42 all have positive optical power. With such a configuration, when light is coupled into the coupling-in grating, it can be further converged and coupled into the waveguide substrate 10, and when propagating in the waveguide substrate 10, it can maintain a convergent state and finally converge to the coupling-out grating, so that more light is transmitted to the coupling-out grating, thereby improving the efficiency of light energy use.

[0050] Since the area of ​​the outcoupling grating is smaller than that of the incoupling grating, in order to make the light diffuse more evenly to the CIS detector 50 after being outcoupled, in some embodiments, the first front outcoupling grating 23, the first rear outcoupling grating 24, the second front outcoupling grating 33, the second rear outcoupling grating 34, the third front outcoupling grating 43 and the third rear outcoupling grating 44 all have negative optical power. In this way, when the light is outcoupled by the outcoupling grating, its exit angle can be expanded by the outcoupling grating, so that the CIS detector 50 can be evenly covered.

[0051] It is worth noting that the light transmission process of the color filter element of the present application is different from the traditional grating light waveguide imaging transmission process, so there is no need to strictly and accurately control the direction of the light beam, but only to ensure that the light beam can be transmitted to the optical signal detection area of ​​the CIS detector 50 with maximum efficiency, so the optical focal length of the grating can be designed more freely. Similarly, for the pupil expansion function of the traditional out-coupling grating, this design can be ignored in the color filter element of the present application, and the pupil expansion function can be avoided as much as possible to ensure that the light transmitted in the out-coupling waveguide is coupled out after only one reflection.

[0052] like Figure 7 and Figure 8 As shown, in some embodiments, the first grating group 20 includes a first front diffraction grating 25 and / or a first rear diffraction grating 26, the first front diffraction grating 25 is disposed on the front surface of the waveguide substrate 10, and the first rear diffraction grating 26 is disposed on the rear surface of the waveguide substrate 10. The second grating group 30 includes a second front diffraction grating 35 and / or a second rear diffraction grating 36, the second front diffraction grating 35 is disposed on the front surface of the waveguide substrate 10, and the second rear diffraction grating 36 is disposed on the rear surface of the waveguide substrate 10. The third grating group 40 includes a third front diffraction grating 45 and / or a third rear diffraction grating 46, the third front diffraction grating 45 is disposed on the front surface of the waveguide substrate 10, and the third rear diffraction grating 46 is disposed on the rear surface of the waveguide substrate 10.

[0053] It can be understood that the first front diffraction grating 25 can be used to deflect the transmission direction of the second band light or the third band light, and the first rear diffraction grating 26 can be used to deflect the transmission direction of the second band light or the third band light; the second front diffraction grating 35 can be used to deflect the transmission direction of the first band light or the third band light, and the second rear diffraction grating 36 can be used to deflect the transmission direction of the first band light or the third band light; the third front diffraction grating 45 can be used to deflect the transmission direction of the first band light or the second band light, and the third rear diffraction grating 46 can be used to deflect the transmission direction of the first band light or the second band light.

[0054] Taking the first pixel area 11 as an example, when the light beam irradiates the first pixel area 11 of the waveguide substrate 10, the first band light in the light beam can directly pass through the first pixel area 11 and be recognized by the first CIS detector 51, while the other band light in the light beam can be transmitted to the corresponding pixel area by the first front diffraction grating 25 or the first rear diffraction grating 26. For example, the second band light can be deflected by the first front diffraction grating 25 in the transmission direction, so that the second band light is diffracted to the second pixel area 12 and is recognized by the second CIS detector 52, and the third band light can be deflected by the first rear diffraction grating 26 in the transmission direction, so that the third band light is diffracted to the third pixel area 13 and is recognized by the third CIS detector 53. Similarly, when the light beam irradiates the second pixel area 12 or the third pixel area 13 of the waveguide substrate 10, the first band light, the second band light and the third band light in the light beam can also be deflected to the corresponding CIS detector 50.

[0055] In some embodiments, the first front diffraction grating 25 includes two first front diffraction sub-gratings, and the grating vector directions of the two first front diffraction sub-gratings are perpendicular to each other, or the first rear diffraction grating 26 includes two first rear diffraction sub-gratings, and the grating vector directions of the two first rear diffraction sub-gratings are perpendicular to each other, the second front diffraction grating 35 includes two second front diffraction sub-gratings, and the grating vector directions of the two second front diffraction sub-gratings are perpendicular to each other, or the second rear diffraction grating 36 includes two second rear diffraction sub-gratings, and the grating vector directions of the two second rear diffraction sub-gratings are perpendicular to each other, the third front diffraction grating 45 includes two third front diffraction sub-gratings, and the grating vector directions of the two third front diffraction sub-gratings are perpendicular to each other, or the third rear diffraction grating 46 includes two mutually perpendicular third rear diffraction sub-gratings, and the grating vector directions of the two third rear diffraction sub-gratings are perpendicular to each other.

[0056] It can be understood that the front diffraction grating or the rear diffraction grating can be a two-dimensional grating, and the first front diffraction grating 25 can be used to deflect the second band light and the third band light at the same time, wherein one first front diffraction sub-grating can be used to deflect the second band light, and another first front diffraction sub-grating can be used to deflect the third band light; the first rear diffraction grating 26 can be used to deflect the second band light and the third band light at the same time, wherein one first rear diffraction sub-grating can be used to deflect the second band light, and another first rear diffraction sub-grating can be used to deflect the third band light. The grating can be used to deflect the third band light; the second front diffraction grating 35 can be used to simultaneously deflect the first band light and the third band light, wherein one second front diffraction sub-grating can be used to deflect the first band light, and another second front diffraction sub-grating can be used to deflect the third band light; the second rear diffraction grating 36 can be used to simultaneously deflect the second band light and the third band light, wherein one second rear diffraction sub-grating can be used to deflect the second band light, and another second rear diffraction sub-grating can be used to deflect the third band light.

[0057] Taking the first pixel area 11 as an example, when the light beam is irradiated to the first pixel area 11 of the waveguide substrate 10, the first band light in the light beam can directly pass through the first pixel area 11 and be recognized by the first CIS detector 51, and the other bands of light in the light beam can be transmitted to the corresponding pixel area by the first front diffraction grating 25 or the first rear diffraction grating 26. When the first front diffraction grating 25 is provided on the front surface of the waveguide substrate 10, the second band light may be deflected by the first front diffraction sub-grating to the second pixel area 12 and recognized by the second CIS detector 52, and the third band light may be deflected by the first front diffraction sub-grating to the third pixel area 13 and recognized by the third CIS detector 53. When the first rear diffraction grating 26 is disposed on the rear surface of the waveguide substrate 10, the second band light may be deflected by the first rear diffraction sub-grating to the second pixel area 12 and recognized by the second CIS detector 52, and the third band light may be deflected by the first rear diffraction sub-grating to the third pixel area 13 and recognized by the third CIS detector 53. Similarly, when the light beam is irradiated to the second pixel area 12 or the third pixel area 13 of the waveguide substrate 10, the first band light, the second band light and the third band light in the light beam may also be deflected to the corresponding CIS detector 50.

[0058] Optionally, in some embodiments, the diffraction grating may be a volume holographic grating or a relief grating, and the grating material may be a photoresist material or a polymer material.

[0059] In some embodiments, the present application does not impose a rigid requirement on the thickness of the waveguide substrate 10 , and the thickness of the waveguide substrate 10 may range from 0.3 mm to 3 mm. When the thickness of the waveguide substrate 10 ranges from 0.3 mm to 3 mm, the utilization efficiency of light energy can be significantly improved.

[0060] Optionally, in some embodiments, the waveguide may be made of glass, resin or other materials.

[0061] Optionally, in some embodiments, in order to maintain the total reflection effect of the waveguide, the air gap between the rear surface of the waveguide substrate 10 and the CIS detector 50 may range from 1 μm to 1 mm.

[0062] Optionally, in some embodiments, the first pixel area 11, the second pixel area 12, and the third pixel area 13 of the waveguide are arranged according to the Bayer array. Among them, the first pixel area 11 is an R (red) pixel area, and the first band light is red light, the second pixel area 12 is a G (green) pixel area, and the second band light is green light, and the third pixel area 13 is a B (blue) pixel area, and the third band light is blue light. The four adjacent pixel areas above, below, left, and right of the first pixel area 11 are the second pixel area 12; the two adjacent pixel areas to the left and right of the second pixel area 12 are the first pixel area 11, the two adjacent pixel areas above and below the second pixel area 12 are the third pixel area 13, and the four adjacent pixel areas above, below, left, and right of the third pixel area 13 are the second pixel area 12.

[0063] The color filter element of the present application is further described below in conjunction with specific embodiments.

[0064] Embodiment 1

[0065] like Figure 1 , Figure 2 and Figure 3As shown, the color filter element of this embodiment may include a waveguide substrate 10, a plurality of first grating groups 20, a plurality of second grating groups 30 and a plurality of third grating groups 40. The waveguide substrate 10 is periodically provided with a plurality of R pixel regions, a plurality of G pixel regions and a plurality of B pixel regions according to the Bayer array. The first grating group 20 includes a first front coupling-in grating 21, a first rear coupling-out grating 24, a first front coupling-out grating 23 and a first rear coupling-out grating 24. The first front coupling-in grating 21 is arranged on the front surface of the waveguide substrate 10; the first rear coupling-in grating 22 is arranged on the rear surface of the waveguide substrate 10; the first front coupling-out grating 23 is arranged on the front surface of the waveguide substrate 10; the first rear coupling-out grating 24 is arranged on the rear surface of the waveguide substrate 10; The second grating group 30 includes a second front coupling grating 31, a second rear coupling grating 34, a second front coupling grating 33 and a second rear coupling grating 34, wherein the second front coupling grating 31 is disposed on the front surface of the waveguide substrate 10; the second rear coupling grating 32 is disposed on the rear surface of the waveguide substrate 10; the second front coupling grating 33 is disposed on the front surface of the waveguide substrate 10; and the second rear coupling grating 34 is disposed on the rear surface of the waveguide substrate 10; The third grating group 40 includes a third front coupling grating 41, a third rear coupling grating 44, a third front coupling grating 43 and a third rear coupling grating 44, wherein the third front coupling grating 41 is disposed on the front surface of the waveguide substrate 10; the third rear coupling grating 42 is disposed on the rear surface of the waveguide substrate 10; the third front coupling grating 43 is disposed on the front surface of the waveguide substrate 10; and the third rear coupling grating 44 is disposed on the rear surface of the waveguide substrate 10; Among them, the first rear coupling grating 22, the first front coupling grating 23, the second rear coupling grating 32, the second front coupling grating 33, the third rear coupling grating 42 and the third front coupling grating 43 are all transmission gratings; the first rear coupling grating 22, the first front coupling grating 23, the second rear coupling grating 32, the second front coupling grating 33, the third rear coupling grating 42 and the third front coupling grating 43 are all reflection gratings.

[0066] The first front outcoupling grating 23 and the first rear outcoupling grating 24 can be used to couple out red light, the first front coupling grating 21 can be used to couple in green light, the first rear coupling grating 22 can be used to couple in blue light, the second front outcoupling grating 33 and the second rear outcoupling grating 34 can be used to couple out green light, the second front coupling grating 31 can be used to couple in red light, the second rear coupling grating 32 can be used to couple in blue light, the third front outcoupling grating 43 and the third rear outcoupling grating 44 can be used to couple out blue light, the third front coupling grating 41 can be used to couple in red light, and the third rear coupling grating 42 can be used to couple in green light. The first CIS detector 51 is used to identify red light, the second CIS detector 52 is used to identify green light, and the third CIS detector 53 is used to identify blue light.

[0067] Taking the R pixel area as an example, when the light beam is irradiated to the R pixel area of ​​the waveguide substrate 10, the red light in the light beam can directly pass through the R pixel area and be recognized by the first CIS detector 51, while the green light in the light beam can be coupled into the waveguide substrate 10 by the first front coupling grating 21, transmitted to the G pixel area through multiple reflections of the waveguide, and coupled out to the second CIS detector 52 by the second front coupling grating 33 or the second rear coupling grating 34 in the G pixel area; the blue light in the light beam can be coupled into the waveguide by the first rear coupling grating 22, transmitted to the B pixel area through multiple reflections of the waveguide, and coupled out to the third CIS detector 53 by the third front coupling grating 43 or the third rear coupling grating 44 in the B pixel area. Similarly, when the light beam is irradiated to the G pixel area and the B pixel area of ​​the waveguide substrate 10, the red light, green light and blue light in the light beam can also be coupled out to the first CIS detector 51, the second CIS detector 52 and the third CIS detector 53, respectively.

[0068] Embodiment 2

[0069] like Figure 4 , Figure 5 and Figure 6 As shown, the color optical waveguide of this embodiment may include a waveguide substrate 10, a plurality of first grating groups 20, a plurality of second grating groups 30 and a plurality of third grating groups 40. The arrangement of the waveguide substrate 10 and the grating groups in this embodiment is the same as the arrangement of the waveguide substrate 10 and the grating groups in the first embodiment. The difference between the second embodiment and the first embodiment is that the first front coupling grating 21, the first rear coupling grating 22, the first front coupling grating 23, the first rear coupling grating 24, the second front coupling grating 31, the second rear coupling grating 32, the second front coupling grating 33, the second rear coupling grating 34, the third front coupling grating 41, the third rear coupling grating 42, the third front coupling grating The grating 43 and the third rear outcoupling grating 44 are both two-dimensional gratings, wherein the first front coupling grating 21 and the first rear coupling grating 22 can both couple in green light and blue light at the same time, and the first front outcoupling grating 23 and the first rear outcoupling grating 24 can couple out red light; the second front coupling grating 31 and the second rear coupling grating 32 can both couple in red light and blue light at the same time, and the second front outcoupling grating 33 and the second rear outcoupling grating 34 can couple out green light; the third front coupling grating 41 and the third rear coupling grating 42 can both couple in red light and green light at the same time, and the third front outcoupling grating 43 and the third rear outcoupling grating 44 can couple out blue light.

[0070] Taking the R pixel area as an example, when the light beam is irradiated to the R pixel area of ​​the waveguide substrate 10, the red light in the light beam can directly pass through the R pixel area and be recognized by the first CIS detector 51, while the green light and the blue light in the light beam can be coupled into the waveguide substrate 10 by the first front coupling grating 21 or the first rear coupling grating 22, and respectively transmitted to the G pixel area and the B pixel area through multiple reflections of the waveguide, and then respectively coupled out to the second CIS detector 52 by the second front coupling grating 33 or the second rear coupling grating 34 in the G pixel area, and coupled out to the third CIS detector 53 by the third front coupling grating 43 or the third rear coupling grating 44 in the B pixel area. Similarly, when the light beam is irradiated to the G pixel area and the B pixel area of ​​the waveguide substrate 10, the red light, the green light and the blue light in the light beam can also be coupled out to the first CIS detector 51, the second CIS detector 52 and the third CIS detector 53, respectively.

[0071] Embodiment 3

[0072] like Figure 7 and Figure 8 As shown, the color filter element of this embodiment may include a waveguide substrate 10, a plurality of first grating groups 20, a plurality of second grating groups 30, and a plurality of third grating groups 40. The waveguide substrate 10 is periodically provided with a plurality of R pixel areas, a plurality of G pixel areas, and a plurality of B pixel areas according to the Bayer array. The first grating group 20 includes a first front diffraction grating 25 and a first rear diffraction grating 26. The first front diffraction grating 25 is arranged on the front surface of the waveguide substrate 10, and the first rear diffraction grating 26 is arranged on the rear surface of the waveguide substrate 10. The second grating group 30 includes a second front diffraction grating 35 and a second rear diffraction grating 36. The second front diffraction grating 35 is arranged on the front surface of the waveguide substrate 10, and the second rear diffraction grating 36 is arranged on the rear surface of the waveguide substrate 10. The third grating group 40 includes a third front diffraction grating 45 and a third rear diffraction grating 46 . The third front diffraction grating 45 is disposed on the front surface of the waveguide substrate 10 , and the third rear diffraction grating 46 is disposed on the rear surface of the waveguide substrate 10 .

[0073] The first front diffraction grating 25 can be used to deflect the transmission direction of green light, and the first rear diffraction grating 26 can be used to deflect the transmission direction of blue light; the second front diffraction grating 35 can be used to deflect the transmission direction of red light, and the second rear diffraction grating 36 can be used to deflect the transmission direction of blue light; the third front diffraction grating 45 can be used to deflect the transmission direction of green light, and the third rear diffraction grating 46 can be used to deflect the transmission direction of red light.

[0074] When the light beam is irradiated to the R pixel area of ​​the waveguide substrate 10, the red light in the light beam can directly pass through the R pixel area and be recognized by the first CIS detector 51, while the green light in the light beam can be deflected by the first front diffraction grating 25 in the transmission direction, so that the green light is diffracted to the G pixel area and recognized by the second CIS detector 52, and the blue light in the light beam can be deflected by the first rear diffraction grating 26 in the transmission direction, so that the blue light is diffracted to the B pixel area and recognized by the third CIS detector 53. When the light beam is irradiated to the G pixel area of ​​the waveguide substrate 10, the green light in the light beam can directly pass through the G pixel area and be recognized by the second CIS detector 52, while the red light in the light beam can be deflected by the second front diffraction grating 35 in the transmission direction, so that the red light is diffracted to the R pixel area and recognized by the first CIS detector 51, and the blue light in the light beam can be deflected by the second rear diffraction grating 36 in the transmission direction, so that the blue light is diffracted to the B pixel area and recognized by the third CIS detector 53. When the light beam is irradiated to the B pixel area of ​​the waveguide substrate 10, the blue light in the light beam can directly pass through the B pixel area and be recognized by the third CIS detector 53, while the green light in the light beam can be deflected by the third front diffraction grating 45 in the transmission direction, so that the green light is diffracted to the G pixel area and recognized by the second CIS detector 52, and the red light in the light beam can be deflected by the third front diffraction grating 45 in the transmission direction, so that the red light is diffracted to the R pixel area and recognized by the first CIS detector 51.

[0075] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0076] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A color filter element, used to be arranged on the photosensitive side of a CIS detector, characterized in that: include: A waveguide substrate, wherein the waveguide substrate has a plurality of first pixel areas, a plurality of second pixel areas, and a plurality of third pixel areas that are periodically arranged, wherein the first pixel areas are used to correspond to a first CIS detector that detects light of a first wavelength band, the second pixel areas are used to correspond to a second CIS detector that detects light of a second wavelength band, and the third pixel areas are used to correspond to a third CIS detector that detects light of a third wavelength band; a plurality of first grating groups, wherein the first grating groups are arranged in the first pixel area, and are used to transmit the first wavelength band light in the first pixel area to the first CIS detector, and transmit the second wavelength band light in the first pixel area to the second pixel area and / or transmit the third wavelength band light in the first pixel area to the third pixel area; a plurality of second grating groups, wherein the second grating groups are arranged in the second pixel area, and are used to transmit the second wavelength band light in the second pixel area to the second CIS detector, and transmit the first wavelength band light in the second pixel area to the first pixel area and / or transmit the third wavelength band light in the second pixel area to the third pixel area; as well as A plurality of third grating groups are arranged in the third pixel area, and are used to transmit the third-band light in the third pixel area to the third CIS detector, and transmit the first-band light in the third pixel area to the first pixel area and / or transmit the second-band light in the third pixel area to the second pixel area.

2. The color filter element according to claim 1, characterized in that The first grating group includes a first front coupling grating arranged on the front surface of the waveguide substrate, a first rear coupling grating arranged on the rear surface of the waveguide substrate, a first front coupling grating arranged on the front surface of the waveguide substrate, and a first rear coupling grating arranged on the rear surface of the waveguide substrate; the second grating group includes a second front coupling grating arranged on the front surface of the waveguide substrate, a second rear coupling grating arranged on the rear surface of the waveguide substrate, a second front coupling grating arranged on the front surface of the waveguide substrate, and a second rear coupling grating arranged on the rear surface of the waveguide substrate; the third grating group includes a first front coupling grating arranged on the front surface of the waveguide substrate, a second rear coupling grating arranged on the rear surface of the waveguide substrate, and a second rear coupling grating arranged on the rear surface of the waveguide substrate. A third front coupling-in grating arranged on the rear surface of the waveguide substrate, a third rear coupling-in grating arranged on the front surface of the waveguide substrate, a third front out coupling-out grating arranged on the rear surface of the waveguide substrate, and a third rear out coupling-out grating arranged on the rear surface of the waveguide substrate, wherein the first front coupling-in grating, the first rear out coupling-out grating, the second front coupling-in grating, the second rear out coupling-out grating, the third front coupling-in grating and the third rear out coupling-out grating are all transmission gratings; and the first rear coupling-in grating, the first front out coupling-out grating, the second rear coupling-in grating, the second front out coupling-out grating, the third rear coupling-in grating and the third front out coupling-out grating are all reflection gratings.

3. The color filter element according to claim 2, characterized in that: The first front coupling-in grating is arranged around the first front coupling-out grating, and the first rear coupling-in grating is arranged around the first rear coupling-out grating; the second front coupling-in grating is arranged around the second front coupling-out grating, and the second rear coupling-in grating is arranged around the second rear coupling-out grating; the third front coupling-in grating is arranged around the third front coupling-out grating, and the third rear coupling-in grating is arranged around the third rear coupling-out grating.

4. The color filter element according to claim 2, characterized in that: The area of ​​the first front coupling-in grating is larger than that of the first front coupling-out grating, and the area of ​​the first rear coupling-in grating is larger than that of the first rear coupling-out grating; the area of ​​the second front coupling-in grating is larger than that of the second front coupling-out grating, and the area of ​​the second rear coupling-in grating is larger than that of the second rear coupling-out grating; the area of ​​the third front coupling-in grating is larger than that of the third front coupling-out grating, and the area of ​​the third rear coupling-in grating is larger than that of the third rear coupling-out grating.

5. The color filter element according to claim 2, characterized in that: The first front coupling grating, the first rear coupling grating, the second front coupling grating, the second rear coupling grating, the third front coupling grating and the third rear coupling grating all have positive optical power.

6. The color filter element according to claim 2, characterized in that: The first front outcoupling grating, the first rear outcoupling grating, the second front outcoupling grating, the second rear outcoupling grating, the third front outcoupling grating and the third rear outcoupling grating all have negative optical power.

7. The color filter element according to claim 1, characterized in that: The first grating group includes a first front diffraction grating arranged on the front surface of the waveguide substrate and / or a first rear diffraction grating arranged on the rear surface of the waveguide substrate; the second grating group includes a second front diffraction grating arranged on the front surface of the waveguide substrate and / or a second rear diffraction grating arranged on the rear surface of the waveguide substrate; the third grating group includes a third front diffraction grating arranged on the front surface of the waveguide substrate and / or a third rear diffraction grating arranged on the rear surface of the waveguide substrate.

8. The color filter element according to claim 7, characterized in that: The first front diffraction grating includes two first front diffraction sub-gratings with grating vector directions perpendicular to each other, or the first rear diffraction grating includes two first rear diffraction sub-gratings with grating vector directions perpendicular to each other, the second front diffraction grating includes two second front diffraction sub-gratings with grating vector directions perpendicular to each other, or the second rear diffraction grating includes two second rear diffraction sub-gratings with grating vector directions perpendicular to each other, the third front diffraction grating includes two third front diffraction sub-gratings with grating vector directions perpendicular to each other, or the third rear diffraction grating includes two third rear diffraction sub-gratings with grating vector directions perpendicular to each other.

9. The color filter element according to any one of claims 1 to 8, characterized in that: The thickness of the waveguide substrate ranges from 0.3 mm to 3 mm.

10. The color filter element according to any one of claims 1 to 8, characterized in that: The air gap between the rear surface of the waveguide substrate and the CIS detector ranges from 1 μm to 1 mm.

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