Image sensor
By using a hybrid color filter in the image sensor and incorporating materials with different refractive indices to induce light-stealing behavior, the problem of light loss in traditional technologies is solved, thereby improving the signal acquisition efficiency and sensitivity of the image sensor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2026-03-13
AI Technical Summary
Traditional phase-detection autofocus technology results in the loss of half of the incident light, leading to poor signal acquisition and affecting the performance of the image sensor.
A hybrid color filter is used, comprising a first material and a second material, both with the same extinction coefficient but different refractive indices. It is designed to directly contact the photodiode without a grid, inducing light-stealing behavior to improve the energy absorption of the photodiode.
It improves the sensitivity and signal acquisition efficiency of the image sensor, reduces light loss, and enhances the performance of phase detection autofocus.
Smart Images
Figure CN121665707A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to an image sensor. Background Technology
[0002] An image sensor is a semiconductor device that converts light images into electrical signals. Image sensors are generally classified into charge-coupled device (CCD) and complementary metal-oxide-semiconductor (CMOS) image sensors. Among the aforementioned image sensors, CMOS image sensors include a photodiode for detecting incident light and converting it into an electrical signal, and logic circuitry for transmitting and processing the electrical signal.
[0003] In recent years, phase detection autofocus (PDAF) technology has been adopted in electronic products such as digital single-lens reflex (DSLR) cameras, digital still cameras (DSC), and smartphone cameras. The traditional principle of phase detection autofocus is to provide a semi-shaded layer on adjacent pixels. The signal difference between these two pixels creates the phase detection autofocus function. However, these two semi-shaded pixels lose half of the incident light, lower than standard green pixels, resulting in poorer signal capture.
[0004] Therefore, the development of a novel image sensor structure that can implement phase detection autofocus and has excellent image capture performance is highly anticipated. Summary of the Invention
[0005] One embodiment of this disclosure provides an image sensor including a phase-detection autofocus unit comprising a plurality of photodiodes and a hybrid color filter disposed on a group of the photodiodes. The hybrid color filter includes a first material and a second material in direct contact with each other, the extinction coefficient of the first material being substantially the same as that of the second material, and the refractive index of the first material being different from that of the second material, wherein the refractive indices of the first material and the second material satisfy the following equation:
[0006] |k L (λ1)-k R (λ1)∣+∣k L (λ2)-k R (λ2)∣+…+∣k L (λ n… )-k R (λ n ) |<(n-1)×0.01,
[0007] Where k L (λ) is the extinction coefficient of the first material, k R(λ) is the extinction coefficient of the second material, n is a positive integer, and λ is the filtering band of the hybrid color filter, which is in the range of 300nm to 2000nm. The difference between the refractive index of the first material and the refractive index of the second material is less than 2.
[0008] In some embodiments, the ratio between the size of the first material and the size of the second material is in the range of 0.5 to 1.5, and the sum of the size of the first material and the size of the second material is equal to the size of two adjacent materials in the photodiode, and the shape of each of the first material and the second material is a square, a rectangle or a trapezoid, in a top view.
[0009] In some embodiments, the image sensor further includes a metalayer disposed on a hybrid color filter, wherein the metalayer contains multiple microstructures.
[0010] In some embodiments, the image sensor further includes a microlens layer disposed on a hybrid color filter.
[0011] In some embodiments, the phase detection autofocus unit includes a grid surrounding a hybrid color filter, and no grid is disposed between the first material and the second material.
[0012] In some embodiments, the group of photodiodes includes a first photodiode and a second photodiode adjacent to the first photodiode, with a first material disposed on the first photodiode and a second material disposed on the second photodiode.
[0013] In some embodiments, the group of photodiodes includes a first photodiode and a second photodiode adjacent to the first photodiode, a first material disposed on the first photodiode, and a second material disposed on the first photodiode and the second photodiode.
[0014] In some embodiments, the group of photodiodes comprises four photodiodes arranged in a 2x2 array, with a first material disposed on two adjacent of the four photodiodes and a second material disposed on the other two adjacent of the four photodiodes.
[0015] In some embodiments, the group of photodiodes comprises four photodiodes arranged in a 2x2 array, a first material comprising two parts disposed on two diagonally opposite sides of the four photodiodes, and a second material comprising two parts disposed on the other two diagonally opposite sides of the four photodiodes.
[0016] In some embodiments, the group of photodiodes comprises nine photodiodes arranged in a 3x3 array, a hybrid color filter is disposed on a middle column of the photodiodes, and the second material comprises two parts disposed on opposite sides of the first material.
[0017] In some embodiments, the phase detection autofocus unit further includes two single-color filters, respectively disposed on the left and right columns of the nine photodiodes, and the filtering band of the hybrid color filter is the same as that of the single-color filter.
[0018] In some embodiments, the group of photodiodes comprises nine photodiodes arranged in a 3x3 array, a hybrid color filter is disposed in the middle row of the nine photodiodes, and the second material comprises two parts disposed on opposite sides of the first material.
[0019] In some embodiments, the phase detection autofocus unit further includes two single-color filters, respectively disposed above and below the nine photodiodes, and the filtering band of the hybrid color filter is the same as that of the single-color filter.
[0020] In some embodiments, the group of photodiodes comprises nine photodiodes arranged in a 3x3 array, a hybrid color filter is disposed in the middle column and middle row of the nine photodiodes, and the second material comprises four parts, respectively disposed on the side of the first material.
[0021] In some embodiments, the phase detection autofocus unit further includes four single-color filters, which are respectively disposed at the four corners of the nine photodiodes, and the filtering band of the hybrid color filter is the same as that of the single-color filter.
[0022] In some embodiments, the group of photodiodes comprises 25 photodiodes arranged in a 5x5 array, a first material is disposed on a central portion of the 25 photodiodes, and a second material comprises two portions disposed on opposite sides of the first material.
[0023] In some embodiments, the phase detection autofocus unit further includes a first single-color filter and a second single-color filter diagonally arranged on 25 photodiodes, and two third single-color filters diagonally arranged on 25 photodiodes, wherein the filtering band of the hybrid color filter is the same as that of the third single-color filters.
[0024] In some embodiments, the filtering band of the hybrid color filter is different from the filtering band of the first single color filter, and the filtering band of the hybrid color filter is different from the filtering band of the second single color filter.
[0025] In some embodiments, the image sensor further includes an additional hybrid color filter, wherein the hybrid color filter and the additional hybrid color filter are respectively disposed on the diagonal of the 25 photodiodes, and the filtering band of the hybrid color filter is the same as that of the additional hybrid color filter.
[0026] In some embodiments, the hybrid color filter corresponds to red, green, blue, yellow, transparent, magenta, or cyan.
[0027] According to embodiments of this disclosure, an image sensor with a PDAF sensing unit is provided. The PDAF sensing unit includes a hybrid color filter comprising a first material and a second material. The extinction coefficient of the first material is substantially equal to that of the second material, and the refractive index of the first material is different from that of the second material. Due to the difference in refractive index between the first and second materials, light-stealing behavior is induced in the PDAF sensing unit to improve the L / R ratio, and the sensitivity of the PDAF sensing unit is also improved. Attached Figure Description
[0028] To make the objectives, features, advantages, and embodiments of this disclosure more apparent and understandable, the accompanying drawings are described in detail below:
[0029] Figure 1 This is a top view schematic diagram of an image sensor according to some embodiments of the present disclosure.
[0030] Figure 2A This is a top view schematic diagram of a PDAF sensing unit in an image sensor according to some embodiments of the present disclosure.
[0031] Figure 2B For along Figure 2A Some embodiments of the PDAF sensing unit are shown in a cross-sectional view along line segment AA.
[0032] Figure 2C This is a cross-sectional view of a PDAF sensing unit according to other embodiments of this disclosure.
[0033] Figure 3 This is a cross-sectional view of a PDAF sensing unit in an image sensor according to some embodiments of the present disclosure.
[0034] Figure 4 This is a cross-sectional view of a PDAF sensing unit in an image sensor according to some embodiments of the present disclosure.
[0035] Figures 5 to 16 These are top views of PDAF sensing units in image sensors according to different embodiments of the present disclosure.
[0036] Figure 17 and Figure 18 These are cross-sectional views of PDAF sensing units in image sensors according to other embodiments of this disclosure.
[0037] The reference numerals in the attached figures are explained as follows:
[0038] 10: Image Sensor
[0039] 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H, 100I, 100J, 100K, 100L: Phase Detection Autofocus (PDAF) sensor unit
[0040] 102: Substrate
[0041] 104, 104L, 104R: Photodiodes
[0042] 1041: First photodiode
[0043] 1042: Second photodiode
[0044] 1043: Third photodiode
[0045] 1044: Fourth photodiode
[0046] 1045: The Fifth Photodiode
[0047] 1046: The Sixth Photodiode
[0048] 1047: The Seventh Photodiode
[0049] 1048: The Eighth Photodiode
[0050] 1049: Ninth photodiode
[0051] 106: Deep trench isolation structure
[0052] 108: Grille
[0053] 110, 170: Single-color filter
[0054] 110R: Red Single-color Filter
[0055] 110G: Green Single-Color Filter
[0056] 110B: Blue Single-Color Filter
[0057] 120, 120A, 120B: Hybrid Color Filters
[0058] 122: Interface
[0059] 130: First Material
[0060] 1301, 1302: Partial
[0061] 140: Second Material
[0062] 1401, 1402, 1403, 1404: Partial
[0063] 150: Super-inspired layer
[0064] 152: Microstructure
[0065] 160: Microlens layer
[0066] 162: Microlenses
[0067] 200: Color sensing unit
[0068] 210: Color Filter
[0069] C L Left column
[0070] C M Middle column
[0071] C R Right column
[0072] L: Incident light
[0073] LL: First incident light
[0074] LR: Second incident light
[0075] R T The upper row
[0076] R M Middle row
[0077] R B The bottom row
[0078] S: Offset Detailed Implementation
[0079] The following drawings disclose multiple embodiments of this disclosure. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details should not be used to limit this disclosure. That is, in some embodiments of this disclosure, these practical details are not essential. Furthermore, for the sake of simplicity, some conventional structures and elements will be shown in a simple schematic manner in the drawings, and in all drawings, the same reference numerals will be used to denote the same or similar elements. And, where feasible, the features of different embodiments can be interchanged.
[0080] Relative terms, such as "below" or "bottom" and "above" or "top," are used to describe the relationship between one element and another shown in the accompanying drawings. Relative terms are used to describe different orientations of the device beyond those depicted in the drawings, which can be understood. For example, if a device in a drawing is flipped, an element that was originally described as being "below" other elements will be oriented as being "above" other elements.
[0081] The terms “include,” “including,” “have,” and similar words used in this article are all open-ended terms, meaning that they include but are not limited to these.
[0082] Reference Figure 1 , Figure 1 This is a top view schematic diagram of an image sensor according to some embodiments of the present disclosure. The image sensor 10 includes at least one phase detection autofocus (PDAF) sensing unit 100 and a plurality of color sensing units 200. Each color sensing unit 200 includes a plurality of color filters 210, wherein the combination of color filters 210 corresponds to red, green, blue, yellow, transparent, magenta, or cyan. In some embodiments, the color filters 210 in each color sensing unit 200 are arranged in a Bayer configuration, and each color filter 210 covers a plurality of photodiodes. The PDAF sensing unit 100 includes a plurality of single-color filters 110 and a hybrid color filter 120. The combination of single-color filters 110 corresponds to red, green, blue, yellow, transparent, magenta, or cyan. The hybrid color filter 120 corresponds to red, green, blue, yellow, transparent, magenta, or cyan. Each single-color filter 110 and the hybrid color filter 120 are respectively covered on multiple photodiodes.
[0083] The hybrid color filter 120 includes a first material 130 and a second material 140, wherein the first material 130 and the second material 140 are in direct contact with each other and there is no grid between them. The extinction coefficient of the first material 130 is substantially the same as that of the second material 140, and the refractive index of the first material 130 is different from that of the second material 140.
[0084] In some embodiments, the extinction coefficient of the first material 130 or the extinction coefficient of the second material 140 is the same as the extinction coefficient of the material of one of the single-color filters 110 in the PDAF sensing unit 100, or the extinction coefficient of the first material 130 or the extinction coefficient of the second material 140 is the same as the extinction coefficient of the material of one of the color filters 210 in the color sensing unit 200.
[0085] The PDAF sensing unit 100 disclosed herein includes a hybrid color filter 120, comprising a first material 130 and a second material 140 having different refractive indices. The PDAF sensing unit 100 thus exhibits light plunder behavior to increase the L / R ratio of the PDAF sensing unit 100 when incident light with an incident angle enters the PDAF sensing unit 100.
[0086] Reference Figure 2A as well as Figure 2B , Figure 2A This is a top view schematic diagram of a PDAF sensing unit in an image sensor according to some embodiments of the present disclosure. Figure 2B For along Figure 2A Some embodiments of the PDAF sensing unit are shown in a cross-sectional view along line segment AA. The PDAF sensing unit 100 includes a plurality of photodiodes 104 formed on a substrate 102, the photodiodes 104 being defined and separated by a deep trench isolation structure 106. The PDAF sensing unit 100 includes a grid 108 disposed on the deep trench isolation structure 106. The grid 108 defines a plurality of cavities, and the PDAF sensing unit 100 includes a single-color filter 110 and a hybrid color filter 120, the single-color filter 110 and the hybrid color filter 120 being disposed on the photodiodes 104 and filling the cavities defined by the grid 108. In some embodiments, each single-color filter 110 and each hybrid color filter 120 covers four photodiodes 104, and each photodiode 104 is square in shape.
[0087] The hybrid color filter 120 includes a first material 130 and a second material 140, which are in direct contact with each other without a grid between them. The extinction coefficient of the first material 130 is substantially equal to that of the second material 140, and the refractive index of the first material 130 is greater than that of the second material 140.
[0088] When incident light L with an incident angle reaches the interface 122 between the first material 130 and the second material 140, light plundering behavior occurs due to the difference in refractive index between the first material 130 and the second material 140. Before the incident light L reaches the deep trench isolation structure 106, the incident light L will split at the interface 122 between the first material 130 and the second material 140.
[0089] The incident light L splits into a first incident light LL and a second incident light LR. The first incident light LL passes through interface 122, while the second incident light LR is reflected by interface 122. The first incident light LL enters the photodiode 104L below it after passing through the first material 130. The second incident light LR enters the photodiode 104R below it after passing through the second material 140.
[0090] Because the refractive index of the first material 130 is greater than that of the second material 140, the first material 130 will capture more light. That is, the energy of the first incident light LL passing through the first material 130 will be greater than the energy of the second incident light LR passing through the second material 140. The L / R ratio, that is, the ratio of the energy received by the photodiode 104L below the first material 130 to the energy received by the photodiode 104R below the second material 140, can therefore increase because the first material 130, with its higher refractive index, captures more light.
[0091] In addition, the incident light L splits before reaching the deep trench isolation structure 106, and there is no semi-shielding layer between the hybrid color filter 120 and the photodiode 104. Therefore, it can be assumed that almost all the energy of the incident light L is absorbed by the photodiode 104 below the hybrid color filter 120. Compared to conventional PDAF technology using a semi-shielding layer, the energy absorbed by the photodiode 104 is significantly increased, and the sensitivity of the PDAF sensing unit 100 is also improved.
[0092] Reference Figure 2CThis is a cross-sectional view of a PDAF sensing unit according to other embodiments of the present disclosure. In some embodiments, the hybrid color filter 120 includes a first material 130 and a second material 140, which are in direct contact with each other without a grid between them. The extinction coefficient of the first material 130 is substantially equal to that of the second material 140, and the refractive index of the second material 140 is greater than that of the first material 130.
[0093] Before the incident light L reaches the deep trench isolation structure 106, the incident light L splits at the interface 122 between the first material 130 and the second material 140. For example, the incident light L splits into a first incident light LL and a second incident light LR, wherein the first incident light LL enters the photodiode 104L below it after passing through the first material 130. The second incident light LR is reflected by the interface 122 and enters the photodiode 104R below it after passing through the second material 140.
[0094] Because the refractive index of the second material 140 is greater than that of the first material 130, the second material 140 will capture more light. That is, the energy of the second incident light LR passing through the second material 140 will be greater than the energy of the first incident light LL passing through the first material 130. The L / R ratio, i.e., the ratio of the energy received by the photodiode 104R below the second material 140 to the energy received by the photodiode 104L below the first material 130, can therefore increase because the second material 140, with its higher refractive index, captures more light. Furthermore, the energy absorbed by the photodiode 104 can be significantly increased, and the sensitivity of the PDAF sensing unit 100 is also improved.
[0095] according to Figures 2A to 2C It is understood that the light-stealing behavior caused by the difference in refractive index between the first material 130 and the second material 140 is introduced into the PDAF sensing unit 100 to enhance the L / R ratio of the PDAF sensing unit 100. In some embodiments, the difference between the refractive index of the first material 130 and the refractive index of the second material 140 is greater than zero and less than 2. In some embodiments, when the difference between the refractive index of the first material 130 and the refractive index of the second material 140 is greater than 0.5, the light-stealing behavior can be clearly observed.
[0096] In some embodiments, the extinction coefficient of the first material 130 is substantially equivalent to the extinction coefficient of the second material 140, and the refractive index of the first material 130 is greater than the refractive index of the second material 140, satisfying the following equation:
[0097] |k L (λ1)-k R (λ1)∣+∣kL (λ2)-k R (λ2)∣+…+∣k L (λ n )-k R (λ n ) |<(n-1)×0.01,
[0098] Where k L (λ) is the extinction coefficient of the first material 130, k R (λ) is the extinction coefficient of the second material 140, n is a positive integer, and λ is the filtering band of the hybrid color filter 120, which is in the range of 300nm to 2000nm.
[0099] In some embodiments, the sum of the dimensions D1 of the first material 130 and D2 of the second material 140 is equal to the dimensions D3 of adjacent elements in the photodiode 104, wherein the dimensions D3 of adjacent elements in the photodiode 104 are measured between the centers of the deep trench isolation structure 106. In some embodiments, the dimension D1 of the first material 130 may be greater than, equal to, or less than the dimension D2 of the second material 140. In some embodiments, the ratio between the dimensions D1 of the first material 130 and D2 of the second material 140 is in the range of 0.5 to 1.5.
[0100] Reference Figure 3 This is a cross-sectional view of a PDAF sensing unit in an image sensor according to some embodiments of the present disclosure. The PDAF sensing unit 100 further includes a meta layer 150 disposed on a hybrid color filter 120 and a single color filter 110. In some embodiments, the meta layer 150 includes a plurality of microstructures 152.
[0101] Reference Figure 4 This is a cross-sectional view of a PDAF sensing unit in an image sensor according to some embodiments of the present disclosure. The PDAF sensing unit 100 further includes a microlens layer 160 disposed on a hybrid color filter 120 and a single color filter 110. In some embodiments, the microlens layer 160 includes a plurality of microlenses 162, and the microlenses 162 are respectively disposed on the corresponding hybrid color filter 120 and single color filter 110.
[0102] Reference Figures 5 to 16 , Figures 5 to 16 These are top-view schematic diagrams of PDAF sensing units in image sensors according to different embodiments of the present disclosure. For ease of explanation, the top-view schematic diagrams show the filter layer and photodiode layer, including the hybrid color filter and the single color filter, separately. Please note... Figures 5 to 16The red, green, and blue referred to in the single color filter 110 and the hybrid color filter 120 are merely examples. The single color filter 110 and the hybrid color filter 120 can correspond to a combination of red, green, blue, yellow, transparent, magenta, or cyan.
[0103] like Figure 5 As shown, the PDAF sensing unit 100A includes 16 photodiodes 104 arranged in a 4x4 array. A hybrid color filter 120 is disposed on a group of these photodiodes 104, such as on the first to fourth photodiodes 1041 to 1044 located in the upper left corner. A red single-color filter 110R, a green single-color filter 110G, and a blue single-color filter 110B are disposed on the remaining photodiodes 104. In some embodiments, the hybrid color filter 120 and the green single-color filter 110G are respectively disposed diagonally on the PDAF sensing unit 100A, and the filtering band of the hybrid color filter 120 is the same as that of the green single-color filter 110G.
[0104] The hybrid color filter 120 includes a first material 130 and a second material 140, which are in direct contact with each other and do not have a grid between them. The extinction coefficients of the first material 130 and the second material 140 are substantially the same, and the refractive index of the first material 130 is different from that of the second material 140.
[0105] The first to fourth photodiodes 1041 to 1044 are arranged in a 2x2 array, wherein the first photodiode 1041 and the fourth photodiode 1044 are diagonally opposite each other, the second photodiode 1042 is adjacent to the first photodiode 1041, and the third photodiode 1043 is adjacent to the fourth photodiode 1044.
[0106] The first material 130 of the hybrid color filter 120 is disposed on the first photodiode 1041 and the third photodiode 1043 in the left column, and the second material 140 of the hybrid color filter 120 is disposed on the second photodiode 1042 and the fourth photodiode 1044 in the right column. The first material 130 and the second material 140 have the same dimensions. Each of the first material 130 and the second material 140 is rectangular in shape, as shown in a top view.
[0107] For reference Figure 6The PDAF sensing unit 100B shown differs from the PDAF sensing unit 100A primarily in the design of the hybrid color filter 120. In some embodiments, the size of the first material 130 differs from the size of the second material 140. For example, the size of the first material 130 is smaller than the size of the second material 140, and the second material 140 is further disposed on the first photodiode 1041 and the third photodiode 1043.
[0108] For reference Figure 7 The PDAF sensing unit 100C shown is primarily different from the PDAF sensing unit 100B in the design of the hybrid color filter 120. In some embodiments, the dimensions of the first material 130 differ from those of the second material 140. Each of the first material 130 and the second material 140 is trapezoidal in shape, as shown in a top view.
[0109] For reference Figure 8 The PDAF sensing unit 100D shown differs from the PDAF sensing unit 100A primarily in the design of the hybrid color filter 120. In some embodiments, the first material 130 comprises two portions 1301 and 1302 respectively disposed diagonally on the group of first to fourth photodiodes 1041 to 1044, such as on the first and fourth photodiodes 1041 and 1044. The second material 140 comprises two additional portions 1401 and 1402 respectively disposed on the group of first to fourth photodiodes 1041 to 1044, such as on the second and third photodiodes 1042 and 1043.
[0110] In some embodiments, the dimensions of each portion 1301, 1302, 1401, 1402 in the first material 130 and the second material 140 are all the same, and the shape of each portion 1301, 1302, 1401, 1402 in the first material 130 and the second material 140 is square, as shown in a top view.
[0111] For reference Figure 9 The PDAF sensing unit 100E shown is primarily different from the PDAF sensing unit 100D in the design of the hybrid color filter 120. In some embodiments, the dimensions of the portions 1301, 1302, 1401, and 1402 in the first material 130 and the second material 140 may be different, and the shapes of the portions 1301, 1302, 1401, and 1402 in the first material 130 and the second material 140 are rectangular, as shown in a top view.
[0112] For reference Figure 10 The PDAF sensing unit 100F shown is primarily different from the PDAF sensing unit 100D in the design of the hybrid color filter 120. In some embodiments, the dimensions of the portions 1301, 1302, 1401, and 1402 in the first material 130 and the second material 140 may be different, and the shapes of the portions 1301, 1302, 1401, and 1402 in the first material 130 and the second material 140 are trapezoidal, as shown in a top view.
[0113] For reference Figure 11 The main difference between the PDAF sensing unit 100G and the PDAF sensing unit 100A shown is that the green single-color filter 110G is replaced by a hybrid color filter 120. The first material 130 and the second material 140 in the hybrid color filter 120 may include multiple portions arranged adjacently or diagonally, the shapes of these portions may be square, rectangular or trapezoidal, and / or the dimensions of these portions may be the same or different.
[0114] For reference Figure 12 The main difference between the PDAF sensing unit 100H and the PDAF sensing unit 100A is that the red single-color filter 110R (or blue single-color filter 110B) is replaced by a hybrid color filter 120, and two green single-color filters 110G are diagonally arranged in the PDAF sensing unit 100H. The first material 130 and the second material 140 in the hybrid color filter 120 may comprise multiple adjacent or diagonally arranged portions, the shapes of which may be square, rectangular, or trapezoidal, and / or the dimensions of which may be the same or different.
[0115] like Figure 13 As shown, the PDAF sensing unit 100A includes 36 photodiodes 104 arranged in a 6x6 array. A hybrid color filter 120 is disposed on one group of these photodiodes 104. A red single-color filter 110R, a green single-color filter 110G, and a blue single-color filter 110B are disposed on the remaining photodiodes 104. In some embodiments, the hybrid color filter 120 and the green single-color filter 110G are respectively disposed diagonally opposite to each other in the PDAF sensing unit 100A, and the filtering band of the hybrid color filter 120 is the same as that of the green single-color filter 110G.
[0116] The first to ninth photodiodes 1041 to 1049 are arranged in a 3x3 array, wherein the first to third photodiodes 1041 to 1043 are positioned in the upper row R. T The fourth to sixth photodiodes 1044 to 1046 are located in the middle row R. M The seventh to ninth photodiodes 1047 to 1049 are located in the lower row R. B The hybrid color filter 120 is located in the middle row R between the first to ninth photodiodes 1041-1049. M And the middle column C M superior.
[0117] More specifically, the first material 130 of the hybrid color filter 120 is disposed in the fifth photodiode 1045, while the second material 140 of the hybrid color filter 120 comprises four portions 1401 to 1404, respectively disposed on the four sides of the first material 130. The four portions 1401 to 1404 of the first material 130 and the second material 140 are in direct contact with each other without having a grid between them. The extinction coefficient of the first material 130 is substantially the same as that of the second material 140, and the refractive index of the first material 130 is different from that of the second material 140. In some embodiments, the dimensions of the first material 130 and each of the four portions 1401 to 1404 of the second material 140 are the same, and the shape of the first material 130 and each of the four portions 1401 to 1404 of the second material 140 is square, as shown in a top view.
[0118] In addition, the PDAF sensing unit 100I includes four single-color filters 170, disposed at the four corners of the group of first to ninth photodiodes 1041-1049. For example, the single-color filters 170 are disposed on the first, third, seventh, and ninth photodiodes 1041, 1043, 1047, and 1049, respectively. The filtering band of the single-color filters 170 is the same as that of the hybrid color filter 120, and also the same as that of the green single-color filter 110G.
[0119] For reference Figure 14 The PDAF sensing unit 100J shown differs from the PDAF sensing unit 100I primarily in that it incorporates two hybrid color filters 120A and 120B on a 6x6 array of photodiodes 104. The hybrid color filter 120A is located in the middle column C of a 3x3 array of photodiodes 104 positioned in the upper left corner. MAbove, the first material 130 of the hybrid color filter 120A is disposed at the center of the nine photodiodes 104, while the second material 140 of the hybrid color filter 120A comprises two parts 1401 and 1402, respectively disposed on the upper and lower sides of the first material 130. The PDAF sensing unit 100J further includes two single color filters 170, disposed in the left column C. L And column C on the right R It is located above and adjacent to the hybrid color filter 120A. The filtering band of the hybrid color filter 120A is the same as that of the single color filter 170.
[0120] In the hybrid color filter 120B, the hybrid color filter 120B is the middle row R of the 3x3 array of photodiodes 104 located in the lower right corner. M In the hybrid color filter 120B, the first material 130 is disposed at the center of the nine photodiodes 104, while the second material 140 of the hybrid color filter 120B comprises two parts 1401 and 1402, respectively disposed on the left and right sides of the first material 130. The PDAF sensing unit 100J further includes two single-color filters 170, disposed in the upper row R. T and the row below R B Above and adjacent to the hybrid color filter 120A. The filtering band of the hybrid color filter 120B is the same as that of the single color filter 170.
[0121] For reference Figure 15 The PDAF sensing unit 100K shown is as follows Figure 16 The PDAF sensing unit 100L is shown. Both the PDAF sensing unit 100K and the PDAF sensing unit 100L contain 25 photodiodes 104 arranged in a 5x5 array. A hybrid color filter 120 is disposed on a group of photodiodes 104. In some embodiments, the first material 130 of the hybrid color filter 120 is disposed at the center of the array of photodiodes 104, while the second material 140 of the hybrid color filter 120 comprises two parts 1401 and 1402, respectively disposed on the left and right sides of the first material 130 (e.g., ...). Figure 15 (as shown) or the top and bottom sides (as shown) Figure 16 (As shown above).
[0122] In some embodiments, the PDAF sensing unit 100K and the PDAF sensing unit 100L respectively include a red single-color filter 110R, two green single-color filters 110G, and a blue single-color filter 110B, which are disposed on other photodiodes 104.
[0123] In some embodiments, a red single-color filter 110R and a blue single-color filter 110B are diagonally positioned on an array of photodiodes 104. In some embodiments, two green single-color filters 110G are diagonally positioned on an array of photodiodes 104, and the filtering band of the hybrid color filter 120 is the same as that of the green single-color filter 110G.
[0124] Reference Figure 17 and Figure 18 These are cross-sectional views of PDAF sensing units in image sensors according to other embodiments of this disclosure. In some embodiments, such as Figure 1 The design of the individual PDAF sensing units 100 in the image sensor 10 shown can be further varied according to their relative positions in the image sensor 10.
[0125] For example, such as Figure 17 The PDAF sensing unit 100 shown is located at or near the center of the image sensor 10. The first material 130 and the second material 140 in the hybrid color filter 120 can be the same size, and the metalayer 150 (or microlens layer 160) will be aligned with the grid 108.
[0126] For example, such as Figure 18 The PDAF sensing unit 100 shown is located at or near the edge of the image sensor 10. The first material 130 and the second material 140 in the hybrid color filter 120 may have different sizes, and the metalayer 150 (or microlens layer 160) is laterally offset from the grid 108 by an offset S.
[0127] According to embodiments of this disclosure, an image sensor with a PDAF sensing unit is provided. The PDAF sensing unit includes a hybrid color filter comprising a first material and a second material. The extinction coefficient of the first material is substantially equal to that of the second material, and the refractive index of the first material is different from that of the second material. Due to the difference in refractive index between the first and second materials, light-stealing behavior is induced in the PDAF sensing unit to improve the L / R ratio, and the sensitivity of the PDAF sensing unit is also improved.
[0128] Although this disclosure has been provided above with reference to embodiments, it is not intended to limit this disclosure. Any person skilled in the art may make various modifications and alterations without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the appended claims.
Claims
1. An image sensor, characterized in that, Include: A phase-detection autofocus unit, comprising: Multiple photodiodes; and A hybrid color filter is disposed on one group of a plurality of photodiodes, wherein the hybrid color filter comprises a first material and a second material in direct contact with each other, the extinction coefficient of the first material being substantially the same as that of the second material, and the refractive index of the first material being different from that of the second material. The refractive indices of the first material and the second material satisfy the following equation: ∣k L (λ1)-k R (λ1)∣+∣k L (λ2)-k R (λ2)∣+…+∣k L (l n )-k R (l n )∣<(n-1)×0.01, Where k L (λ) is the extinction coefficient of the first material, k R (λ) is the extinction coefficient of the second material, n is a positive integer, and λ is the filtering band of the hybrid color filter, which is in the range of 300nm to 2000nm. The difference between the refractive index of the first material and the refractive index of the second material is less than 2.
2. The image sensor of claim 1, wherein the ratio between the size of the first material and the size of the second material is in the range of 0.5 to 1.5, and the sum of the size of the first material and the size of the second material is equal to the size of two adjacent photodiodes among the plurality of photodiodes, and each of the first material and the second material is square, rectangular or trapezoidal in a top view.
3. The image sensor of claim 1, wherein the hybrid color filter corresponds to red, green, blue, yellow, transparent, magenta, or cyan, and the image sensor further comprises: A metalayer is disposed on the hybrid color filter, wherein the metalayer comprises multiple microstructures; or A microlens layer is disposed on the hybrid color filter.
4. The image sensor of claim 1, wherein the phase detection autofocus unit includes a grid surrounding the hybrid color filter, and the grid is not disposed between the first material and the second material.
5. The image sensor of claim 1, wherein the group of the plurality of photodiodes includes a first photodiode and a second photodiode adjacent to the first photodiode, the first material being disposed on the first photodiode, and the second material being disposed on the second photodiode or disposed on both the first photodiode and the second photodiode.
6. The image sensor of claim 1, wherein the group of the plurality of photodiodes comprises four photodiodes arranged in a 2x2 array, wherein: The first material is disposed on two adjacent surfaces of the four photodiodes, and the second material is disposed on the other two adjacent surfaces of the four photodiodes; or The first material comprises two parts, which are respectively disposed on two diagonally opposite sides of the four photodiodes. The second material comprises two parts, which are respectively disposed on the other two diagonally opposite sides of the four photodiodes.
7. The image sensor of claim 1, wherein the group of the plurality of photodiodes comprises nine photodiodes arranged in a 3x3 array, the hybrid color filter is disposed on a middle column of the nine photodiodes, and the second material comprises two parts disposed on opposite sides of the first material, the phase detection autofocus unit further comprises two single color filters disposed on a left column and a right column of the nine photodiodes, and the filtering band of the hybrid color filter is the same as the filtering band of the single color filter.
8. The image sensor of claim 1, wherein the group of the plurality of photodiodes comprises nine photodiodes arranged in a 3x3 array, the hybrid color filter is disposed on a middle row of the nine photodiodes, and the second material comprises two parts disposed on opposite sides of the first material, the phase detection autofocus unit further comprises two single color filters disposed on an upper row and a lower row of the nine photodiodes, and the filtering band of the hybrid color filter is the same as the filtering band of the single color filter.
9. The image sensor of claim 1, wherein the group of the plurality of photodiodes comprises nine photodiodes arranged in a 3x3 array, the hybrid color filter is disposed on a middle column and a middle row of the nine photodiodes, and the second material comprises four portions disposed on the sides of the first material, the phase detection autofocus unit further comprises four single color filters disposed at the four corners of the nine photodiodes, and the filtering band of the hybrid color filter is the same as the filtering band of the plurality of single color filters.
10. The image sensor of claim 1, wherein the group of the plurality of photodiodes comprises 25 photodiodes arranged in a 5x5 array, the first material is disposed on a central portion of the 25 photodiodes, and the second material comprises two portions disposed on opposite sides of the first material, the phase detection autofocus unit further comprising a first single-color filter and a second single-color filter diagonally disposed on the 25 photodiodes, and two third single-color filters diagonally disposed on the 25 photodiodes, wherein the filtering band of the hybrid color filter is the same as the filtering band of the third single-color filters.
11. The image sensor of claim 10, wherein the filtering band of the hybrid color filter is different from the filtering band of the first single color filter, and the filtering band of the hybrid color filter is different from the filtering band of the second single color filter.
12. The image sensor of claim 1, further comprising an additional hybrid color filter, wherein the hybrid color filter and the additional hybrid color filter are respectively disposed on the diagonal of the plurality of photodiodes, and the filtering band of the hybrid color filter is the same as the filtering band of the additional hybrid color filter.