KR20210048401A - Image sensor including color separating lens array and electronic apparatus including the image sensor - Google Patents

Abstract

Disclosed is an image sensor including a color separating lens array. The disclosed image sensor includes: a sensor substrate including a plurality of first photo-sensing cells and a plurality of second photo-sensing cells for sensing light; and a color separation lens array having a plurality of first regions respectively corresponding to the plurality of first photo-sensing cells and having a first microstructure, and a plurality of second regions respectively corresponding to the plurality of second photo-sensing cells and having a second microstructure different from the first microstructure, wherein light of a first wavelength and light of a second wavelength that are different from each other, among the incident light incident on the color separation lens array, are branched in different directions, thereby focusing on the first photo-sensing cell and the second photo-sensing cell, respectively.

Description

An image sensor including a color separating lens array and an electronic apparatus including the image sensor.

The disclosed embodiments relate to an image sensor including a color separation lens array and an electronic device including an image sensor, and more particularly, an image sensor and an image including a color separation lens array capable of separating and condensing incident light by wavelength. It relates to an electronic device including a sensor.

Image sensors typically detect the color of incident light using a color filter. However, since the color filter absorbs light of a color other than the light of the corresponding color, the light utilization efficiency may be deteriorated. For example, when an RGB color filter is used, only 1/3 of the incident light is transmitted and the remaining 2/3 is absorbed, so that the light utilization efficiency is only about 33%. Therefore, in the case of a color display device or a color image sensor, most of the light loss occurs in the color filter.

An image sensor with improved light utilization efficiency is provided by using a color separation lens array capable of separating and condensing incident light by wavelength.

It provides an electronic device including an image sensor.

An image sensor according to an exemplary embodiment includes a sensor substrate including a plurality of first photo-sensing cells and a plurality of second photo-sensing cells that sense light, and each corresponding to the plurality of first photo-sensing cells, A color separation lens array including a plurality of first regions having a structure, and a plurality of second regions each corresponding to the plurality of second light sensing cells and having a second microstructure different from the first microstructure; In the first microstructure and the second microstructure, light of a first wavelength and light of a second wavelength different from among incident light incident on the color separation lens array are diverged in different directions, respectively, so that a first light sensing cell is formed. And a phase distribution condensed on the second light sensing cell at positions passing through the first region and the second region, and positions of the first region and the second region at the center of the color separation lens array are respectively The positions of the corresponding first light sensing cells and the second light sensing cells coincide with the positions of the corresponding first and second light sensing cells, and the positions of the first and second regions in the periphery of the color separation lens array are respectively The light sensing cell may be shifted toward the center of the color separation lens array.

The degree to which the first region and the second region at the periphery of the color separation lens array are shifted with respect to the corresponding first and second light sensing cells, respectively, increases as the distance from the center of the color separation lens array increases. It can be big.

를 만족할 수 있으며, 여기서 d는 상기 색분리 렌즈 어레이의 하부 표면과 상기 센서 기판의 상부 표면 사이의 최단 직선 거리이고, CRA’는 상기 센서 기판에 입사하는 빛의 입사각이다.The distance s at which the first and second regions are shifted with respect to the corresponding first and second photosensitive cells, respectively, is

Wherein d is the shortest linear distance between the lower surface of the color separation lens array and the upper surface of the sensor substrate, and CRA' is the incident angle of light incident on the sensor substrate.

For example, in the first microstructure and the second microstructure, at a position immediately after passing through the color separation lens array, light of a first wavelength is 2Nπ at the center of the first light sensing cell, and the second light senses A phase distribution of (2N-1)π can be formed at the center of the cell. Here, N is an integer greater than 0.

For example, in the first microstructure and the second microstructure, at a position immediately after passing through the color separation lens array, light of a second wavelength is (2M-1)π at the center of the first light sensing cell, A phase distribution of 2Mπ may be formed in the center of the second light sensing cell. Here, M is an integer greater than 0.

The image sensor may further include a spacer layer disposed between the sensor substrate and the color separation lens array to form a distance between the sensor substrate and the color separation lens array.

When the theoretical thickness of the spacer layer is h _t , and the pitch of each of the first and second light sensing cells is p, the thickness h of the spacer layer is h _t -p ≤ h ≤ h _t -p , The theoretical thickness of the spacer layer may be a focal length of the color separation lens array at a center wavelength of a wavelength band of incident light color-separated by the color separation lens array.

When the refractive index of the spacer layer is n and the center wavelength of the wavelength band of light color-separated by the color separation lens array is λ ₀ , the theoretical thickness h _t of the spacer layer is the following equation:

으로 표현될 수 있다.

It can be expressed as

The sensor substrate further includes a plurality of third photo-sensing cells and a plurality of fourth photo-sensing cells for sensing light, and the color separation lens array corresponds to the plurality of third photo-sensing cells, 2 A plurality of third regions having a third microstructure different from the microstructure, and a plurality of fourth microstructures each corresponding to the plurality of fourth light sensing cells and having a fourth microstructure different from the first to third microstructures A region is included, and each of the first region, the second region, the third region, and the fourth region may be respectively arranged along the four quadrants.

Positions of the first, second, third, and fourth regions of the color separation lens array in the center of the image sensor are respectively corresponding to the first light sensing cell, the second light sensing cell, and the third light. The first region, the second region, the third region, and the fourth region of the color separation lens array at the periphery of the image sensor correspond to the positions of the sensing cell and the fourth light sensing cell, respectively. The light sensing cell, the second light sensing cell, the third light sensing cell, and the fourth light sensing cell may be shifted toward the center of the image sensor.

The first, second, third, and fourth regions of the color separation lens array at the periphery of the image sensor respectively correspond to a first light sensing cell, a second light sensing cell, and a third light sensing cell. , And the degree of shift with respect to the fourth light sensing cell may increase as the distance from the center of the image sensor increases.

In the first to fourth microstructures, light having different first wavelengths to third wavelengths among incident light incident on the color separation lens array is diverged in different directions, so that light of the first wavelength is converted into the first light. The first phase distribution in which light of a sensing cell and the fourth light sensing cell is condensed, light of a second wavelength is condensed on the second light sensing cell, and light of a third wavelength is condensed to the third light sensing cell. It can be formed in the region through the fourth region.

For example, the first wavelength may be green light, the second wavelength may be blue light, and the third wavelength may be red light.

The first to fourth microstructures include: light having a first wavelength at a position immediately after passing through the color separation lens array is 2Nπ at a center of the first photosensitive cell and a center of the fourth photosensitive cell, A phase distribution of (2N-1)π is formed at the center of the second photosensitive cell and the center of the third photosensitive cell, and light of the second wavelength is transmitted at a position immediately after passing through the color separation lens array. (2M-1)π from the center of the first photosensitive cell and the center of the fourth photosensitive cell, 2Mπ from the center of the second photosensitive cell, and (2M-2) from the center of the third photosensitive cell A phase distribution that is larger than π and smaller than (2M-1)π is formed, and at a position immediately after passing through the color separation lens array, light of a third wavelength is detected at the center of the first light sensing cell and the fourth light sensing. A phase distribution greater than (2L-1)π at the center of the cell, 2Lπ at the center of the third photosensitive cell, and less than (2L-2)π at the center of the second photosensitive cell Can be formed. Here, L is an integer greater than 0.

The first to fourth microstructures of the first to fourth regions include a plurality of nanoposts, and the first to fourth regions have at least one of the shape, size, and arrangement of the nanoposts different from each other. I can.

For example, the image sensor has a pixel arrangement structure in which a plurality of unit pixels including a red pixel, a green pixel, and a blue pixel are repeatedly arranged, and is provided in a region corresponding to a green pixel among the first to fourth regions. The resulting nanoposts may have different distribution rules along a first direction and a second direction perpendicular to the first direction.

Nanoposts provided in regions corresponding to blue and red pixels among the first to fourth regions may have a symmetrical distribution rule along the first and second directions.

Each of the plurality of nanoposts includes a first nanopost and a second nanopost stacked on the first nanopost, and the position of the second nanopost in the center of the image sensor is the position of the first nanopost and Coincidentally, the second nanoposts at the periphery of the image sensor may be shifted toward the center of the image sensor with respect to the first nanoposts.

The degree to which the second nanopost is shifted with respect to the first nanopost in the periphery of the image sensor may increase as the distance from the center of the image sensor increases.

Each of the plurality of nanoposts includes a first nanopost, a second nanopost stacked on the first nanopost, and a third nanopost stacked on the second nanopost. 2 The position of the nanopost and the position of the third nanopost coincide with the position of the first nanopost, and the second nanopost from the periphery of the image sensor is directed toward the center of the image sensor with respect to the first nanopost. And the third nanopost may be shifted toward the center of the image sensor with respect to the second nanopost.

The line width of the nanoposts disposed in any one of the first, second, third, and fourth areas at the periphery of the image sensor is a nano-post disposed at the same location in the same area from the center of the image sensor. May be larger than the line width of the post.

When the line width of the nanopost at the periphery of the image sensor is w, and the line width of the nanopost at the center of the image sensor is w ₀ ,

을 만족할 수 있으며,

Can be satisfied,

Here, CRA is an angle of incidence of light incident on the color separation lens array.

The line width of the nanopost at the edge of the image sensor may be 2.5% to 6.5% larger than the line width of the nanopost at the center of the image sensor.

The color separation lens array may further include a plurality of first regions and a plurality of second regions that are disposed to protrude from the edge of the sensor substrate and do not face any light sensing cells of the sensor substrate in a vertical direction. .

The total area of the color separation lens array may be smaller than the total area of the sensor substrate.

The color separation lens array includes a first color separation lens array and a second color separation lens array disposed on the first color separation lens array, and a first area and a second area of the first color separation lens array The first microstructure and the second microstructure include a plurality of nanoposts, and the first and second microstructures of the first region and the second region of the second color separation lens array include a plurality of nanoposts, , The arrangement of the plurality of nanoposts of the first color separation lens array may be different from the arrangement of the plurality of nanoposts of the second color separation lens array.

An image sensor according to another exemplary embodiment includes a sensor substrate including a plurality of first photo-sensing cells and a plurality of second photo-sensing cells for sensing light, and a first dielectric material having a first refractive index and forming a first pattern, and A plurality of first regions having a second refractive index smaller than the first refractive index, having a second dielectric filled between the first dielectrics of the first pattern, and respectively corresponding to the plurality of first light sensing cells, and a first refractive index. And a first dielectric material that forms a second pattern that is different from the first pattern, and a second dielectric having a second refractive index less than the first refractive index, and having a second dielectric filled between the first dielectrics of the second pattern, and detecting the plurality of second photos And a color separation lens array corresponding to each cell, wherein the first region and the second region have different first and second wavelengths of incident light incident on the color separation lens array. A phase distribution branched in the direction and condensed on the first and second light sensing cells, respectively, is formed at a position passing through the first region and the second region, and a second region of the first region and the second region is formed. The shape of the first pattern and the shape of the second pattern may gradually change from the center of the color separation lens array toward the periphery of the color separation lens array.

An electronic device according to another embodiment includes: an image pickup unit configured to form an optical image by focusing light reflected from a subject; And the above-described image sensor for converting the optical image formed by the imaging unit into an electrical signal.

For example, the electronic device may be a smart phone, a mobile phone, a personal digital assistant (PDA), a laptop, or a personal computer (PC).

Since the disclosed color separation lens array can separate and condense light by wavelength without absorbing or blocking incident light, it is possible to improve the light utilization efficiency of the image sensor. In addition, the image sensor employing the disclosed color separation lens array can maintain the Bayer pattern method generally adopted in the image sensor, and thus can utilize the pixel structure and image processing algorithm of the existing image sensor. In addition, an image sensor employing the disclosed color separation lens array does not require a separate microlens for condensing light onto a pixel.

1 is a block diagram of an image sensor according to an exemplary embodiment.
2A to 2C exemplarily show various pixel arrangements of a pixel array of an image sensor.
3 is a conceptual diagram showing a schematic structure and operation of a color separation lens array according to an exemplary embodiment.
4A and 4B are schematic cross-sectional views of a pixel array of an image sensor according to an embodiment, and FIG. 5A is a plan view schematically showing an arrangement of photosensitive cells in a pixel array of an image sensor, and FIG. 5B is a plan view exemplarily showing a form in which a plurality of nanoposts are arranged in a plurality of regions of a color separation lens array in a pixel array of an image sensor, and FIG. 5C is a partially enlarged plan view of FIG. 5B.
6A and 6B are diagrams for computational simulation of a phase distribution of blue light passing through a color separation lens array and a focusing distribution of blue light in an opposing light sensing cell, and FIG. 6C is a second color separation lens array corresponding to a blue pixel. The moving direction of the blue light incident on the region and its periphery is shown as an example, and FIG. 6D exemplarily shows a micro lens array that acts equivalently to a color separation lens array for blue light.
7A and 7B are diagrams that simulate the phase distribution of green light passing through the color separation lens array and the focusing distribution of green light in the opposing photosensitive cells, and FIG. 7C is a first diagram of a color separation lens array corresponding to a green pixel. The moving direction of the green light incident on the region and its periphery is shown as an example, and FIG. 7D exemplarily shows a micro lens array that acts equivalently to a color separation lens array for green light.
8A and 8B are diagrams that simulate the phase distribution of red light passing through the color separation lens array and the focusing distribution of red light in an opposing photosensitive cell, and FIG. 8C is a third color separation lens array corresponding to a red pixel. The traveling direction of the red light incident on the region and its periphery is shown as an example, and FIG. 8D exemplarily shows a micro lens array that acts equivalently to a color separation lens array for red light.
9A to 9E are graphs exemplarily showing changes in efficiency of the color separation lens array according to the distance between the color separation lens array and the sensor substrate when the pitch of the photosensitive cells is 0.7 μm.
10A to 10E are graphs exemplarily showing changes in efficiency of the color separation lens array according to the distance between the color separation lens array and the sensor substrate when the pitch of the light sensing cells is 0.8 μm.
11A to 11E are graphs exemplarily showing changes in efficiency of the color separation lens array according to the distance between the color separation lens array and the sensor substrate when the pitch of the photosensitive cells is 1.0 μm.
12 is a perspective view showing an exemplary form of a nanopost that may be employed in a color separation lens array of an image sensor according to an exemplary embodiment.
13A to 13H are plan views showing exemplary shapes of nanoposts that may be employed in a color separation lens array of an image sensor according to another exemplary embodiment.
14 is a plan view illustrating an arrangement of a plurality of nanoposts constituting a color separation lens array of an image sensor according to another exemplary embodiment.
15 is a plan view exemplarily showing an arrangement of a plurality of nanoposts forming a color separation lens array of an image sensor according to another exemplary embodiment.
16 is a plan view illustrating an arrangement of a plurality of nanoposts constituting a color separation lens array of an image sensor according to another exemplary embodiment.
17 is a plan view illustrating an arrangement of a plurality of nanoposts constituting a color separation lens array of an image sensor according to another exemplary embodiment.
18 is a graph exemplarily showing spectral distributions of light incident on a red pixel, a green pixel, and a blue pixel of the image sensor including the color separation lens array of FIG. 17.
19A and 19B are cross-sectional views illustrating a schematic structure of a pixel array of an image sensor according to another exemplary embodiment, respectively.
20 and 21 are graphs showing spectral distributions of light incident on a red pixel, a green pixel, and a blue pixel of an image sensor according to an exemplary embodiment, respectively, when a color filter is provided and a color filter is provided. It is for the case that it is not.
22 is a conceptual diagram schematically showing a camera according to an embodiment.
23A to 23C are plan views showing a change in the arrangement shape of the nanoposts of the color separation lens array according to the position on the image sensor.
24 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor according to another exemplary embodiment.
25 is a plan view exemplarily showing a shift form of nanoposts arranged in two dimensions in a color separation lens array applied to the image sensor of the camera shown in FIG. 22.
26 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor including a color separation lens array shown in FIG. 25.
FIG. 27 is a perspective view illustrating an exemplary shape of a nanopost employed in the color separation lens array of the image sensor of FIG. 26.
28 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor according to another exemplary embodiment.
29A to 29C are graphs showing spectral distributions of light incident on a red pixel, a green pixel, and a blue pixel of the image sensor according to an exemplary embodiment. If not considered, the case where the position of the nanopost is changed in consideration of the change in the principal ray angle, and the case in which the nanopost is configured in two stages in consideration of the change in the principal ray angle.
30A and 30B are plan views illustrating a line width change of a nanopost according to a position on an image sensor according to another exemplary embodiment.
FIG. 31 is a graph exemplarily showing a spectral distribution of light incident on a red pixel, a green pixel, and a blue pixel of the image sensor illustrated in FIG. 30.
32 and 33 are plan views showing various shapes of nanoposts used in a color separation lens array according to another exemplary embodiment.
34 and 35 are cross-sectional views showing various cross-sectional shapes of nanoposts used in a color separation lens array according to another embodiment.
36 is a cross-sectional view illustrating a schematic structure of a pixel array of an image sensor according to another exemplary embodiment.
37 is a conceptual diagram showing a schematic structure and operation of a color separation lens array according to another embodiment.
38 is a plan view illustrating a unit pattern array of a color separation lens array that can be applied to a Bayer pattern type image sensor.
39 is a cross-sectional view illustrating a vertical cross section of the unit pattern array shown in FIG. 38 taken along the line AA′.
40 is a cross-sectional view illustrating a vertical cross section of the unit pattern array shown in FIG. 38 taken along line BB′.
41 is a plan view illustrating an arrangement of a color separation lens array including a plurality of unit pattern arrays illustrated in FIG. 38.
FIG. 42A is an exemplary view of a first area of the unit pattern array illustrated in FIG. 38, and FIG. 42B is an exemplary view of a pixel of an image sensor corresponding thereto and pixels surrounding the same.
43A is an exemplary view of a second area of the unit pattern array illustrated in FIG. 38, and FIG. 43B is an exemplary view of a pixel of an image sensor corresponding thereto and pixels surrounding the same.
FIG. 44A exemplarily shows a third area of the unit pattern array shown in FIG. 38, and FIG. 44B exemplarily shows a pixel of an image sensor corresponding thereto and a pixel surrounding it.
FIG. 45A exemplarily shows a fourth region of the unit pattern array illustrated in FIG. 38, and FIG. 45B exemplarily shows a pixel of an image sensor corresponding thereto and a pixel surrounding the same.
46 is a plan view exemplarily showing a shape of a unit pattern array of a color separation lens array according to another embodiment.
47 is a plan view exemplarily showing a shape of a unit pattern array of a color separation lens array according to another exemplary embodiment.
48A and 48B are schematic cross-sectional views of different cross-sections of a pixel array of an image sensor employing a color separation lens array.
49 is a plan view illustrating a color separation lens array according to another exemplary embodiment.
50 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor including the color separation lens array illustrated in FIG. 49.
51 is a plan view illustrating an arrangement of a plurality of unit pattern arrays of a color separation lens array according to another exemplary embodiment.
52 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor according to another exemplary embodiment.
53 is a schematic block diagram of an electronic device including an image sensor according to embodiments.
54 to 64 show various examples of electronic devices to which an image sensor according to embodiments is applied.

Hereinafter, an image sensor including a color separation lens array and an electronic device including the same will be described in detail with reference to the accompanying drawings. The described embodiments are merely exemplary, and various modifications are possible from these embodiments. In the following drawings, the same reference numerals refer to the same components, and the size of each component in the drawings may be exaggerated for clarity and convenience of description.

Hereinafter, the expression described as "upper" or "upper" may include not only those that are directly above/below/left/right in contact, but also those that are above/below/left/right in a non-contact manner.

Terms such as first and second may be used to describe various components, but are used only for the purpose of distinguishing one component from other components. These terms are not intended to limit differences in materials or structures of components.

Singular expressions include plural expressions unless the context clearly indicates otherwise. In addition, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

In addition, terms such as "... unit" and "module" described in the specification mean units that process functions or operations, which may be implemented as hardware or software, or as a combination of hardware and software.

The use of the term "above" and similar reference terms may correspond to both the singular and the plural.

The steps constituting the method may be performed in any suitable order unless there is a clear statement that the steps constituting the method should be performed in the order described. In addition, the use of all exemplary terms (eg, etc.) is merely for describing technical ideas in detail, and the scope of the rights is not limited by these terms unless limited by claims.

1 is a schematic block diagram of an image sensor according to an exemplary embodiment. Referring to FIG. 1, the image sensor 1000 may include a pixel array 1100, a timing controller 1010, a row decoder 1020, and an output circuit 1030. The image sensor may be a charge coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor.

The pixel array 1100 includes pixels that are two-dimensionally arranged along a plurality of rows and columns. The row decoder 1020 selects one of the rows of the pixel array 1100 in response to a row address signal output from the timing controller 1010. The output circuit 1030 outputs a light detection signal in column units from a plurality of pixels arranged along the selected row. To this end, the output circuit 1030 may include a column decoder and an analog to digital converter (ADC). For example, the output circuit 1030 may include a plurality of ADCs disposed for each column between the column decoder and the pixel array 1100 or one ADC disposed at an output terminal of the column decoder. The timing controller 1010, the row decoder 1020, and the output circuit 1030 may be implemented as a single chip or separate chips. A processor for processing the image signal output through the output circuit 1030 may be implemented as a single chip together with the timing controller 1010, the row decoder 1020, and the output circuit 1030.

The pixel array 1100 may include a plurality of pixels sensing light of different wavelengths. Pixels may be arranged in various ways as shown in FIGS. 2A to 2C.

First, FIG. 2A shows a Bayer pattern generally adopted in the image sensor 1000. Referring to FIG. 2A, one unit pixel includes four quadrant regions, and the first to fourth quadrants are respectively a blue pixel (B), a green pixel (G), a red pixel (R), and a green color. It can be a pixel (G). These unit pixels are repeatedly arranged two-dimensionally along a first direction (X direction) and a second direction (Y direction). In other words, two green pixels (G) are arranged in one diagonal direction within a 2×2 array-type unit pixel, and one blue pixel (B) and one red pixel (R) in the other diagonal direction, respectively. Is placed. Looking at the overall pixel arrangement, a first row in which a plurality of green pixels (G) and a plurality of blue pixels (B) are alternately arranged along a first direction, and a plurality of red pixels (R) and a plurality of green pixels (G) are The second rows alternately arranged along the first direction are repeatedly arranged.

However, the arrangement method of the pixel array 1100 is not limited only to the Bayer pattern, and various arrangement methods other than the Bayer pattern are possible. For example, referring to FIG. 2B, a magenta pixel (M), a cyan pixel (C), a yellow pixel (Y), and a green pixel (G) represent one unit pixel. The configuration of the CYGM method is also possible. Further, referring to FIG. 2C, an RGBW arrangement in which a green pixel (G), a red pixel (R), a blue pixel (B), and a white pixel (W) constitute one unit pixel is also possible. Also, although not shown, the unit pixel may have a 3×2 array form. In addition, the pixels of the pixel array 1100 may be arranged in various ways according to the color characteristics of the image sensor 1000. Hereinafter, for convenience, the pixel array 1100 of the image sensor 1000 will be described as having a Bayer pattern, but the principles of the embodiments described below may be applied to a pixel array other than a Bayer pattern.

According to an embodiment, the pixel array 1100 of the image sensor 1000 may include a color separation lens array configured to condense light of a corresponding color to each pixel. 3 is a conceptual diagram showing a schematic structure and operation of a color separation lens array according to an exemplary embodiment. Referring to FIG. 3, the color separation lens array 130 includes nanoposts NP disposed on the same plane according to a predetermined rule. The color separation lens array 130 may be disposed on the spacer layer 120.

Here, the rule is applied to parameters such as the shape, size (width, height), spacing, and arrangement shape of the nanopost (NP), and the color separation lens array 130 is intended to be implemented for the incident light (Li). It may be determined according to the target phase distribution (TP). The target phase distribution TP may be determined in consideration of the target regions R1 and R2 to be condensed by separating the wavelength of the incident light Li. The target phase distribution TP is displayed between the color separation lens array 130 and the target regions R1 and R2, but this is merely for convenience of illustration. The actual target phase distribution TP is the position immediately after the incident light Li passes through the color separation lens array 130, for example, the lower surface of the color separation lens array 130 or the upper surface of the spacer layer 120 Means the phase distribution at

The color separation lens array 130 may include a first region 131 and a second region 132 each having different first and second microstructures. For example, each of the first region 131 and the second region 132 may include one or a plurality of nanoposts NP. The first region 131 and the second region 132 are disposed to face the first target region R1 and the second target region R2, respectively, and may correspond to each other on a one-to-one basis. Although it is shown that three nanoposts NP are disposed in each of the first region 131 and the second region 132, this is exemplary. In addition, the nanoposts NP are shown to be entirely located within one of the first region 131 and the second region 132, but are not limited thereto, and some of the nanoposts NP are the first region 131 It may be disposed at the boundary between the and the second region 132.

The nanoposts NP of the color separation lens array 130 may form a phase distribution in which light of different wavelengths included in the incident light Li is diverged in different directions and condensed. For example, the light Lλ1 of the first wavelength included in the incident light Li has a first phase distribution, and the light Lλ2 of the second wavelength forms a target phase distribution TP having a second phase distribution. , The shape, size, and arrangement of the nanoposts NP distributed in the first region 131 and the second region 132 may be determined. According to the target phase distribution TP, the array of nanoposts NP and the light of the first wavelength (Lλ1) and the light of the second wavelength ( Lλ2) can be condensed.

A rule in which the nanoposts NP is disposed in the first region 131 and a rule disposed in the second region 132 may be different from each other. In other words, any one of the shape, size, and arrangement of the nanoposts NP provided in the first region 131 may be different from the shape and size arrangement of the nanoposts NP provided in the second region 132. .

The nanopost NP may have a shape dimension of a sub-wavelength smaller than a wavelength band to be branched. The nanopost NP may have a shape dimension smaller than the shorter of the first wavelength and the second wavelength, and when the incident light Li is visible light, the nanopost NP may have a dimension smaller than 400 nm, 300 nm, or 200 nm.

The nanopost NP may be made of a material having a refractive index higher than that of surrounding materials. For example, the nanopost (NP) may be made of c-Si, p-Si, a-Si and III-V compound semiconductors (GaP, GaN, GaAs, etc.), SiC, TiO2, SiN, and/or combinations thereof. have. The nanopost (NP) having a difference in refractive index from the surrounding material may change the phase of passing light. This is due to the phase delay caused by the shape dimension of the sub-wavelength, and the degree of the phase delay is determined by the detailed shape dimension and arrangement shape of the nanopost (NP). The surrounding material may be made of a dielectric material material having a refractive index lower than that of the nanopost (NP), for example, SiO2 or air.

The first wavelength λ1 and the second wavelength λ2 may be a visible light wavelength band, but are not limited thereto, and various wavelength bands may be implemented according to the rules of the arranged nanoposts NP. FIG. 3 illustrates that two wavelengths are branched and condensed, but the present invention is not limited thereto, and incident light may be divided and condensed in three or more directions depending on the wavelength.

Hereinafter, an example in which the above-described color separation lens array 130 is applied to the pixel array 1100 of the image sensor 1000 will be described in more detail.

4A and 4B are cross-sectional views of a pixel array according to an exemplary embodiment, FIG. 5A is a plan view schematically showing an arrangement of photosensitive cells of the pixel array, and FIG. 5B is a configuration in which nanoposts of a color separation lens array are arranged. This is an exemplary plan view.

4A and 4B, the pixel array 1100 is disposed on a sensor substrate 110 and a sensor substrate 110 including a plurality of light sensing cells 111, 112, 113, and 114 for sensing light. And a transparent spacer layer 120 and a color separation lens array 130 disposed on the spacer layer 120.

The sensor substrate 110 includes a first photo-sensing cell 111, a second photo-sensing cell 112, a third photo-sensing cell 113, and a fourth photo-sensing cell 114 that converts light into an electrical signal. Can include. As shown in FIG. 4A, the first photosensitive cells 111 and the second photosensitive cells 112 are alternately arranged along the first direction (X direction), and the position in the Y direction is shown in FIG. 4B in different cross-sections. As shown, the third light sensing cells 113 and the fourth light sensing cells 114 may be alternately arranged. The division of the area is for sensing incident light by dividing the incident light into a pixel unit. For example, the first light sensing cell 111 and the fourth light sensing cell 114 receive light of a first wavelength corresponding to the first pixel. Sensing, the second light sensing cell 112 senses light of a second wavelength corresponding to the second pixel, and the third light sensing cell 113 senses light of a third wavelength corresponding to the third pixel. I can. Hereinafter, light of the first wavelength is green light, light of the second wavelength is blue light, and light of the third wavelength is red light, and the first, second, and third pixels are green pixels (G) and blue pixels ( B), the case of the red pixel R will be described as an example. Although not shown at the boundary between cells, a separator for cell separation may be further formed.

The spacer layer 120 supports the color separation lens array 130 and serves to maintain a constant gap between the sensor substrate 110 and the color separation lens array 130, and may be made of a material transparent to visible light. . For example, the spacer layer 120 has a refractive index lower than the refractive index of the nanopost (NP) of the color separation lens array 130, such as SiO2, silanol-based spin on glass (SOG), etc. It can be made of a dielectric material having a low absorption rate.

The color separation lens array 130 includes nanoposts NPs arranged in a predetermined rule. Although not shown, the color separation lens array 130 may further include a protective layer protecting the nanopost NP. The protective layer may be made of a dielectric material having a refractive index lower than that of a material constituting the nanopost NP.

The color separation lens array 130 is divided into a plurality of regions 131, 132, 133, and 134 that correspond to the plurality of light sensing cells 111, 112, 113, and 114 on a one-to-one basis and face each other. One or a plurality of nanoposts NP may be disposed in each of the plurality of regions 131, 132, 133, and 134, and any one of a shape, size, and arrangement may be different depending on the region.

The color separation lens array 130 divides and condenses light of a first wavelength by the first photo-sensing cell 111 and the fourth photo-sensing cell 114, and the second light-sensing cell 112 The light is branched and condensed, and a region is divided so that light of a third wavelength is divided and condensed by the third light sensing cell 113, and the size, shape, and arrangement of the nanoposts NP are determined for each region.

When the pixel array 1100 has the arrangement of the Bayer pattern as shown in FIG. 2A, the first light sensing cell 111 and the fourth light sensing cell 114 of FIG. 5A correspond to the green pixel G, and , The second photosensitive cell 112 corresponds to the blue pixel (B), and the third photosensitive cell 113 corresponds to the red pixel (R).

Referring to FIG. 5B, the first and fourth regions 131 and 134 of the color separation lens array 130 correspond to the green pixel G, and the second photosensitive cell 112 and the second region 132 This corresponds to the blue pixel B, and the third light sensing cell 113 and the third region 133 correspond to the red pixel R. Accordingly, the color separation lens array 130 includes a plurality of unit pattern arrays arranged in two dimensions, and each unit pattern array includes a first region 131 and a second region 132 arranged in a 2×2 shape. , A third area 133, and a fourth area 134.

5B, the first and fourth regions 131 and 134 corresponding to the green pixel G, the second region 132 corresponding to the blue pixel B, and the red pixel R The third regions 133 may include cylindrical nanoposts NP having a circular cross-section. Nanoposts (NP) having different cross-sectional areas are disposed in the centers of the first region 131, the second region 132, the third region 133, and the fourth region 134, and The nanoposts NP may also be disposed at the intersection of the pixel boundary lines. The cross-sectional area of the nanoposts NP disposed at the boundary between pixels may have a smaller cross-sectional area than the nanoposts NP disposed at the center of the pixel.

5C shows the arrangement of nanoposts NPs in a partial region of FIG. 5B, that is, the first to fourth regions 131, 132, 133, and 134 constituting the unit pattern array. In FIG. 5C, nanoposts (NPs) are indicated as p1 to p9 according to detailed positions in the unit pattern array. Referring to FIG. 5C, the cross-sectional area of the nanoposts p1 disposed in the center of the first region 131 and the nanoposts p4 disposed in the center of the fourth region 134 among the nanoposts NP is limited. 2 A nanopost that is larger than the cross-sectional area of the nanopost (p2) disposed in the center of the area 132 or the nanopost (p3) disposed in the center of the third area 133, and is disposed in the center of the second area 132 The cross-sectional area of (p2) is larger than the cross-sectional area of the nanoposts p3 disposed in the center of the third area 133. However, this is only an example, and nanoposts (NPs) of various shapes, sizes, and arrangements may be applied as needed.

The nanoposts NP provided in the first and fourth regions 131 and 134 corresponding to the green pixel G follow different distribution rules along the first direction (X direction) and the second direction (Y direction). I can have it. For example, the nanoposts NP disposed in the first and fourth regions 131 and 134 may have different size arrangements along the first direction (X direction) and the second direction (Y direction). As shown in FIG. 5C, of the nanoposts NP, the nanoposts p5 positioned at the boundary between the first region 131 and the second region 132 adjacent in the first direction (X direction) The cross-sectional area and the cross-sectional area of the nanoposts p6 positioned at the boundary between the third region 133 adjacent in the second direction (Y direction) are different from each other. Similarly, the cross-sectional area of the nanopost p7 positioned at the boundary between the fourth region 134 and the third region 133 adjacent in the first direction (X direction) and the second region adjacent in the second direction (Y direction) The cross-sectional areas of the nanoposts p8 positioned at the boundary with the region 132 are different from each other.

On the other hand, the nanoposts NP disposed in the second region 132 corresponding to the blue pixel B and the third region 133 corresponding to the red pixel R are It can have a symmetrical distribution rule along the direction (Y direction). As shown in FIG. 5C, of the nanoposts NP, a nanopost p5 and a second direction (Y direction) placed at the boundary between the second region 132 and pixels adjacent in the first direction (X direction) The cross-sectional areas of the nanoposts p6 placed at the boundary between adjacent pixels are the same, and the nanoposts p7 and the second nanoposts placed at the boundary between adjacent pixels in the first direction (X direction) in the third region 133 are the same. The cross-sectional areas of the nanoposts p6 placed at the boundary between adjacent pixels in the direction (Y direction) are the same.

Meanwhile, the first region 131, the second region 132, the third region 133, and the fourth region 134 have four corners, that is, the nanoposts p9 disposed at the intersections of the four regions. They have the same cross-sectional area. This distribution is due to the pixel arrangement of the Bayer pattern. In the blue pixel (B) and the red pixel (R), the pixels adjacent in the first direction (X direction) and the second direction (Y direction) are the same as the green pixel (G). In the green pixel G, the pixels adjacent in the first direction (X direction) are blue pixels B, and the pixels adjacent in the second direction (Y direction) are red pixels R, which are different from each other. In the corresponding green pixel G, the pixels adjacent in the first direction (X direction) are the red pixels R, and the pixels adjacent in the second direction (Y direction) are the blue pixels B, which are different from each other. In addition, the green pixels G corresponding to the first region 131 and the fourth region 134 are green pixels G, which are adjacent to each other in four diagonal directions, and correspond to the second region 132. In the blue pixel (B), pixels adjacent in four diagonal directions are the same as the red pixels (R), and the red pixels (R) corresponding to the third region 133 are blue pixels (B) adjacent in four diagonal directions. ) Is the same as each other. Accordingly, in the second region 132 and the third region 133 respectively corresponding to the blue pixel B and the red pixel R, the nanoposts NP are arranged in a form of 4-fold symmetry. In addition, nanoposts NP may be arranged in the form of 2-fold symmetry in the first and fourth regions 131 and 134 corresponding to the green pixel G. In particular, the first region 131 and the fourth region 134 are rotated 90 degrees with respect to each other.

All of the nanoposts NP are illustrated to have a symmetrical circular cross-sectional shape, but are not limited thereto, and some nanoposts having an asymmetrical cross-sectional shape may be included. For example, the first region 131 and the fourth region 134 corresponding to the green pixel G have an asymmetric cross-sectional shape having different widths in the first direction (X direction) and the second direction (Y direction). Nanoposts are employed, and in the second region 132 and the third region 133 respectively corresponding to the blue pixel (B) and the red pixel (R), a first direction (X direction) and a second direction (Y direction) A nanopost having a symmetrical cross-sectional shape having the same width of) may be employed.

The illustrated arrangement rule of the color separation lens array 130 is that light of a first wavelength is branched and condensed to the first light sensing cell 111 and the fourth light sensing cell 114, and the second light sensing cell 112 It is an example for implementing a target phase distribution in which the light of the second wavelength is branched and condensed by the light of the second wavelength in the third light sensing cell 113 and the light of the third wavelength is branched and condensed in the third light sensing cell 113, and limited to the illustrated pattern is no.

At a position passing through the color separation lens array 130, a phase at which light of the first wavelength is condensed to the first and fourth light sensing cells 111 and 114 is formed, and the second light sensing cell 112 The shape, size, and arrangement of the nanoposts NP provided in each region of the color separation lens array 130 may be determined so as to form a phase that does not proceed to the and the third light sensing cell 113.

Similarly, a phase in which light of a second wavelength is condensed to the second light sensing cell 112 at a position passing through the color separation lens array 130 is formed, and the first light sensing cell 111 and the third light sensing cell ( 113), and the shape, size, and arrangement of the nanoposts NP provided in each region of the color separation lens array 130 to form a phase that does not proceed to the fourth light sensing cell 114 .

Similarly, a phase in which light of a third wavelength is condensed to the third light sensing cell 113 at a position passing through the color separation lens array 130 is formed, and the first light sensing cell 111 and the second light sensing cell are formed. The shape, size, and arrangement of the nanoposts (NP) provided in each region of the color separation lens array 130 may be determined so as to form a phase that does not proceed to 112 and the fourth light sensing cell 114. have.

The shape, size, and/or arrangement of the nanopost (NP) that satisfies all of these conditions may be determined, and the color separation lens array 130 allows the light immediately after passing through it to have a target phase distribution as follows. can do. At a position immediately after passing through the color separation lens array 130, that is, on the lower surface of the color separation lens array 130 or the upper surface of the spacer layer 120, the phase of the light of the first wavelength is the first light sensing cell ( 2Nπ at the center of the first region 131 corresponding to 111) and the center of the fourth region 134 corresponding to the fourth light sensing cell 114, and the second light corresponding to the second light sensing cell 112 The central portion of the region 132 and the central portion of the third region 132 corresponding to the third sensing cell 113 may be a distribution indicating a phase of (2N-1)π. Here, N is an integer greater than 0. In other words, the phase of the light of the first wavelength at the position immediately after passing through the color separation lens array 130 is maximized at the center of the first region 131 and the center of the fourth region 134, and the first region As the distance from the center of 131 and the center of the fourth area 134 gradually decreases in the shape of a concentric circle, the center of the second area 132 and the center of the third area 132 may be minimized. For example, in the case of N=1, the phase of green light at a position passing through the color separation lens array 130 is 2π at the center of the first region 131 and the center of the fourth region 134, and the second region ( It may be π at the center of 132 and the center of the third area 132. Here, the phase may mean a phase value relative to a phase immediately before light passes through the nanopost NP.

In addition, the phase of the light of the second wavelength at the position immediately after passing through the color separation lens array 130 is 2Mπ at the center of the second region 132 corresponding to the second light sensing cell 112 and the first light sensing cell In the center of the first area 131 corresponding to (111) and the center of the fourth area 134 corresponding to the fourth light-sensing cell 114, (2M-1)π and the third light-sensing cell 113 In the central portion of the third region 133 corresponding to, the distribution may be greater than (2M-2)π and smaller than (2M-1)π. Here, M is an integer greater than 0. In other words, the phase of the light of the second wavelength at the position immediately after passing through the color separation lens array 130 is maximized at the center of the second region 132, and the further away from the center of the second region 132, the concentric circles. The shape gradually decreases and becomes a local minimum in the center of the third area 133. For example, in the case of M=1, the phase of the light of the second wavelength at the position passing through the color separation lens array 130 is 2π at the center of the second region 132 and the center of the first region 131 and the second wavelength. 4 may be π at the center of the area 134 and about 0.2π to 0.7π at the center of the third area 133.

Likewise, the phase of the light of the third wavelength at the position immediately after passing through the color separation lens array 130 is 2Lπ at the center of the third region 133 corresponding to the third light sensing cell 113 and the first light sensing The center of the first region 131 corresponding to the cell 111 and the fourth region 134 corresponding to the fourth light sensing cell 114 is (2L-1) π, and the second light sensing cell 112 is In the center of the corresponding second region 132, it may be larger than (2L-2)π and smaller than (2L-1)π. Here, L is an integer greater than 0. In other words, the phase of the light of the third wavelength at the position immediately after passing through the color separation lens array 130 becomes maximum in the center of the third area 133, and the further away from the center of the third area 133, It gradually decreases in the shape of a concentric circle, and is locally minimized in the center of the second region 132. For example, in the case of L=1, the phase of the light of the third wavelength at the position passing through the color separation lens array 130 is 2π at the center of the third area 133, and the center of the first area 131 4 may be π at the center of the area 134 and about 0.2π to 0.7π at the center of the second area 132.

As mentioned above, the target phase distribution means a phase distribution of light at a position immediately after passing through the color separation lens array 130. When the light passing through the color separation lens array 130 has such a phase distribution, the first to third wavelengths of light are collected in the corresponding first to fourth light sensing cells 111 to 114, respectively. . In other words, the light transmitted through the color separation lens array 130 may be divided according to a wavelength and proceed in different directions to obtain an effect of condensing light.

In this way, a predetermined propagation distance requirement may be determined so that light of a corresponding wavelength is condensed to the corresponding light sensing cell, and accordingly, the thickness h of the spacer layer 120 may be determined. The thickness h of the spacer layer 120 may vary depending on the wavelength λ that is a branching target, the pixel size, and the arrangement period p of the photosensitive cells. The thickness (h) of the spacer layer 120 may be greater than the center wavelength (λ) of the visible light wavelength band to be branched, and compared to the photosensitive cell arrangement period (p), which is the distance between the centers of adjacent photosensitive cells, 1p It can be in the range of ~3p. Specifically, the thickness h of the spacer layer 120 may range from 500 nm to 5 μm. For more detailed details of setting the thickness h of the spacer layer 120, referring to FIGS. 9A to 9E, 10A to 10E, and 11A to 11E, it will be described later.

6A and 6B are diagrams for computational simulation of the phase distribution of blue light passing through the color separation lens array and the focusing distribution of blue light in the facing light sensing cell, and FIG. 6C is a color separation lens array corresponding to the blue pixel (B). The second region of and the direction of blue light incident thereto are illustrated as an example, and FIG. 6D exemplarily shows a microlens array that acts equivalently to a color separation lens array for blue light.

Looking at the phase distribution illustrated in FIG. 6A, the phase at the center of the region corresponding to the blue pixel B is approximately 2π, and the phase at the center of the region corresponding to the adjacent green pixel G is approximately π. Value, and the phase at the center of the area corresponding to the red pixel R in the diagonal direction is approximately smaller than π (eg, about 0.2π to 0.7π).

This phase distribution may represent a focusing distribution of blue light as shown in FIG. 6B. Most of the blue light is condensed in the area corresponding to the blue pixel B, and the blue light hardly reaches the area corresponding to the other pixel.

As a result, the second region 132 corresponding to the blue pixel B and the blue light incident thereto pass through the color separation lens array 130 and then proceed as shown in FIG. 6C. For example, of incident light incident on some of the second region 132 and other regions surrounding the second region 132 of the color separation lens array 130, blue light is the second region directly under the second region 132. It is condensed on the light sensing cell 112. In other words, one blue pixel B includes blue light coming from the second region 132 corresponding to the blue pixel B, and two first regions 131 adjacent to the second region 132 in the horizontal direction. Blue light coming from, blue light coming from two fourth areas 134 adjacent to the second area 132 in a vertical direction, and four third areas 113 adjacent to the second area 132 in a diagonal direction. Blue light that comes is incident.

Accordingly, as shown in FIG. 6D, the color separation lens array 130 may play an equivalent role to an array of a plurality of micro lenses ML1 arranged around the second light sensing cell 112 for blue light. . Since each equivalent microlens ML1 is larger than the corresponding second light sensing cell 112, the second light sensing cell 112 as well as the blue light incident on the region of the second light sensing cell 112 Blue light incident to another surrounding area may also be condensed to the second light sensing cell 112. For example, each microlens ML1 is about 4 times larger than the corresponding second light sensing cell 112, and the four sides of each microlens ML1 are parallel to the four sides of the second light sensing cell 112. can do.

7A and 7B are diagrams that simulate the phase distribution of green light passing through the color separation lens array and the focusing distribution of green light in the opposing photosensitive cells, and FIG. 7C is a first diagram of a color separation lens array corresponding to a green pixel. The moving direction of the green light incident on the area, the fourth area, and the periphery thereof is shown as an example, and FIG. 7D exemplarily shows a microlens array that acts equivalently to a color separation lens array for green light.

Looking at the phase distribution illustrated in FIG. 7A, the phase at the center of the area corresponding to the green pixel G is approximately 2π, and at the center of the area corresponding to the adjacent blue pixel B and the red pixel R. The phase roughly represents the value of π.

This phase distribution may represent a focusing distribution of green light as shown in FIG. 7B. The green light is divided into areas corresponding to the two green pixels G and condensed, and the green light hardly reaches the areas corresponding to the other pixels.

As a result, the first and fourth regions 131 and 134 corresponding to the green pixel G and the green light incident thereto pass through the color separation lens array 130 and then proceed as shown in FIG. 7C. do. For example, among incident light incident on a part of the first region 131 and other regions surrounding the first region 131 of the color separation lens array 130, green light is the first region directly under the first region 131. It is condensed on the light sensing cell 111. Also, although not shown, among the incident light incident on some of the fourth region 134 and other regions surrounding the fourth region 134 of the color separation lens array 130, the green light is directly under the fourth region 134. It is condensed on the fourth light sensing cell 114. In other words, in one green pixel G, green light from the first region 131 or the fourth region 134 corresponding to the green pixel G, the first region 131 or the fourth region 134 The green light coming from the two second regions 132 and the two third regions 113 adjacent to each other in the horizontal and vertical directions is incident.

Accordingly, as shown in FIG. 7D, the color separation lens array 130 includes a plurality of micro lenses ML2 arranged around the first and fourth light sensing cells 111 and 114 for green light. It can play an equivalent role to an array. Since each of the equivalent micro lenses ML2 is larger than the first photo-sensing cell 111 or the fourth photo-sensing cell 114 corresponding thereto, the first photo-sensing cell 111 and the fourth photo-sensing cell 114 ), as well as green light incident on the other areas surrounding the first and fourth photo-sensing cells 111 and 114, as well as the first photo-sensing cell 111 and the fourth photo-sensing cell. It can be condensed at (114). For example, each micro-lens ML2 is about twice as large as the first light-sensing cell 111 or the fourth light-sensing cell 114 corresponding thereto, and the first light-sensing cell 111 and the corresponding 4 It may be arranged to be in contact with the light sensing cell 114 in a diagonal direction.

8A and 8B are diagrams that simulate the phase distribution of red light passing through the color separation lens array and the focusing distribution of red light in an opposing light sensing cell, and FIG. 8C is a diagram illustrating a color separation lens array corresponding to a red pixel. 3 exemplarily shows the traveling direction of red light incident on the region and its periphery, and FIG. 8D exemplarily shows a microlens array that acts equivalently to the color separation lens array for the red pixel R. FIG.

Looking at the phase distribution illustrated in FIG. 8A, the phase at the center of the region corresponding to the red pixel R is approximately 2π, and the phase at the center of the region corresponding to the adjacent green pixel G is approximately π. Value, and the phase at the center of the area corresponding to the blue pixel B in the diagonal direction is approximately smaller than π (eg, about 0.2π to 0.7π).

This phase distribution may represent a focusing distribution of red light as shown in FIG. 8B. The red light is condensed in the area corresponding to the red pixel R, and the red light hardly reaches the area corresponding to the other pixels.

As a result, the third region 133 corresponding to the red pixel R and the light incident thereto pass through the color separation lens array 130 and then proceed as shown in FIG. 8C. For example, of incident light incident on some of the third area 133 and other areas surrounding the third area 133 of the color separation lens array 130, the red light is the third area directly under the third area 133. It is condensed on the light sensing cell 113. In other words, one red pixel R includes red light coming from the third region 133 corresponding to the red pixel R, and two fourth regions 134 adjacent to the third region 133 in the horizontal direction. Red light coming from, red light coming from two first areas 131 adjacent to the third area 133 in the vertical direction, and red light coming from four second areas 132 adjacent to the third area 133 in a diagonal direction. Red light enters.

Accordingly, as shown in FIG. 8D, the color separation lens array 130 may play a role equivalent to an array of a plurality of micro lenses ML3 arranged around the third light sensing cell 113 for red light. . Since each equivalent microlens ML3 is larger than the corresponding third light sensing cell 113, not only the red light incident on the region of the third light sensing cell 113 but also the third light sensing cell 113 Red light incident to another surrounding area may also be condensed to the third light sensing cell 113. For example, each microlens ML3 is about 4 times larger than the corresponding third light sensing cell 113, and the four sides of each microlens ML3 are parallel to the four sides of the third light sensing cell 113. can do.

6C, 6D, 7C, 7D, 8C, and 8D are differently expressed. Among the incident light incident on the first region 131 of the color separation lens array 130, green light is The first light sensing cell 111 corresponding to the first region 131 proceeds toward the center, and the blue light is applied to the second light sensing cell around the first light sensing cell 111 corresponding to the first region 131. The red light travels toward the central portion of 112 ), and the red light proceeds toward the central portion of the third optical sensing cell 113 around the first optical sensing cell 111 corresponding to the first region 131. In addition, among the incident light incident on the second region 132 of the color separation lens array 130, the blue light proceeds toward the center of the second light sensing cell 112 corresponding to the second region 132, and the green light is The second light-sensing cell 111 and the fourth light-sensing cell 114 around the second light-sensing cell 112 corresponding to the second area 132 are directed toward the center of the second area 132, and the red light is transmitted to the second area 132 It proceeds toward the center of the third light-sensing cell 113 around the second light-sensing cell 112 corresponding to ). Similarly, among the incident light incident on the third area 133 of the color separation lens array 130, the red light proceeds toward the center of the third light sensing cell 113 corresponding to the third area 133, and the green light is The first light sensing cell 111 and the fourth light sensing cell 114 around the third light sensing cell 113 corresponding to the third region 133 are directed toward the center of the third region 133, and the blue light is transmitted to the third region 133. ), the second light sensing cell 112 around the third light sensing cell 113 corresponding to ). Finally, among the incident light incident on the fourth region 134 of the color separation lens array 130, the green light proceeds toward the center of the fourth light sensing cell 114 corresponding to the fourth region 134, and the blue light Silver proceeds toward the center of the second light sensing cell 112 around the fourth light sensing cell 114 corresponding to the fourth region 134, and the red light senses the fourth light corresponding to the fourth region 134. It proceeds toward the center of the third light sensing cell 113 around the cell 114.

Such color separation and light collection may be performed more effectively by appropriately setting the thickness of the spacer layer 120. For example, when the theoretical thickness _{of the spacer layer 120 is the refractive index of the spacer layer 120 with respect to the wavelength of h t} and λ ₀ is n, and the pitch of the photosensitive cell is p, the following equation (1) may be satisfied. I can.

_{Here, the theoretical thickness h t} of the spacer layer 120 is a focal point at which light having a wavelength of λ ₀ is condensed on the upper surface of the light sensing cells 111, 112, 113 and 114 by the color separation lens array 130. Can mean distance. In other words, _{light having a wavelength of λ 0} may pass through the color separation lens array 130 and be focused at a distance _{h t} from the lower surface of the color separation lens array 130.

As described in Equation 1, the theoretical thickness h _t of the spacer layer 120 varies depending on the pitch (p) of the photosensitive cells 111, 112, 113, 114 and the refractive index (n) of the spacer layer 120 I can. For example, the center wavelength (λ ₀ ) of the visible light band is 540 nm, the pitch (p) of the light sensing cells 111, 112, 113, 114 is 0.8 μm, and the spacer layer 120 has a wavelength of 540 nm. Assuming that the refractive index (n) is 1.46, the theoretical thickness h _t of the spacer layer 120, that is, the distance between the lower surface of the color separation lens array 130 and the upper surface of the sensor substrate 110 may be about 1.64 μm. have. However, the actual thickness of the spacer layer 120 need not be limited only to the _{theoretical thickness (h t) described in Equation (1).} For example, the actual thickness of the spacer layer 120 may be selected within a predetermined range based on _{the theoretical thickness h t} in consideration of the efficiency of the color separation lens array 130.

9A to 9E show the color separation lens array 130 according to the distance between the color separation lens array 130 and the sensor substrate 110 when the pitch of the photosensitive cells 111, 112, 113, and 114 is 0.7 μm. ) Is a graph showing the change in efficiency. 9A is a color separation lens for blue light incident on the second light sensing cell 112 from the first to fourth regions 131, 132, 133, and 134 constituting the unit pattern array of the color separation lens array 130 The light collection efficiency of the array 130 is shown, and FIG. 9B shows the first to fourth regions 131, 132, 133, and 134 constituting the unit pattern array. 114) shows the condensing efficiency of the color separation lens array 130 with respect to the green light incident, and FIG. 9C shows the third light detection from the first to fourth regions 131, 132, 133, and 134 constituting the unit pattern array. It shows the condensing efficiency of the color separation lens array 130 for red light incident on the cell 113.

In the case of FIGS. 9A and 9C, since four regions are arranged for one light sensing cell, the theoretical maximum value is 4. In the case of FIG. 9B, since four regions are arranged for two light sensing cells, the theoretical maximum value is 2. In the graphs of FIGS. 9A to 9C, the distance of the color separation lens array 130 having the highest light collection efficiency becomes the theoretical thickness h _t that satisfies Equation 1. 9A to 9C, the theoretical thickness h _t varies slightly depending on the wavelength.

9D is a graph showing an example of a change in efficiency of a color separation lens array in consideration of a sensitivity characteristic of a human eye to visible light. For example, the human eye is typically the most sensitive to green light and the least sensitive to blue light. Therefore, the graph of FIG. 9D can be obtained by assigning the lowest weight to the graph of Fig. 9A, giving the graph of Fig. 9C a higher weight than the blue light, and giving the highest weight to Fig. 9B and then averaging the summed values. . 9E is a graph showing the results of normalizing the graph of FIG. 9D.

Referring to the graphs of FIGS. 9D and 9E, when the pitch of the photosensitive cells 111, 112, 113, and 114 is 0.7 μm, a color separation lens array ( 130) is the highest at a distance of about 1.2 μm. Further, the efficiency of the color separation lens array 130 becomes about 80% of the maximum efficiency at a distance of about 0.5 μm, and about 95% of the maximum efficiency at a distance of about 1.9 μm.

10A to 10E show the color separation lens array 130 according to the distance between the color separation lens array 130 and the sensor substrate 110 when the pitch of the photosensitive cells 111, 112, 113, and 114 is 0.8 μm. ) Is a graph showing the change in efficiency. 10A to 10E, when the pitch of the photosensitive cells 111, 112, 113, and 114 is 0.8 μm, the color separation lens array 130 for the entire visible light considering the sensitivity characteristics of the human eye The efficiency of is highest at a distance of about 1.64 μm. In addition, the efficiency of the color separation lens array 130 becomes about 85% of the maximum efficiency at a distance of about 0.8 μm, and about 93% of the maximum efficiency at a distance of about 2.5 μm.

11A to 11E show the color separation lens array 130 according to the distance between the color separation lens array 130 and the sensor substrate 110 when the pitch of the photosensitive cells 111, 112, 113, and 114 is 1.0 μm. ) Is a graph showing the change in efficiency. 11A to 11E, when the pitch of the photosensitive cells 111, 112, 113, and 114 is 1.0 μm, a color separation lens array 130 for the entire visible light considering the sensitivity characteristics of the human eye The efficiency of is highest at a distance of about 2.6 μm. In addition, the efficiency of the color separation lens array 130 becomes about 87% of the maximum efficiency at a distance of about 1.6 μm, and about 94% of the maximum efficiency at a distance of about 3.6 μm.

As a result, even if the actual thickness (h) of the spacer layer 120 _{is larger or smaller than the theoretical thickness (h t} ) of Equation 1 by the pitch p of the photosensitive cells 111, 112, 113, 114, It can be seen that the color separation lens array 130 has a high efficiency of 80% or more, 90% or more, or 95% or more of the maximum efficiency. Considering the above result, the actual thickness (h) of the spacer layer 120 is h _t - may be chosen within the range of _{p ≤ h ≤ h t + p} .

Since the above-described color separation lens array 130 can diverge by wavelength and condense the branched light to a specific region without absorbing or blocking incident light, it is possible to improve the light utilization efficiency of the image sensor. In addition, since the color separation lens array 130 has improved color separation performance, an image sensor employing the color separation lens array 130 may have excellent color purity. In addition, the image sensor employing the color separation lens array 130 can maintain the Bayer pattern method generally adopted in the image sensor, and thus can utilize the same image processing algorithm as the existing pixel structure. Moreover, since the color separation lens array 130 can also serve as a lens for condensing incident light, an image sensor employing the color separation lens array 130 provides a separate microlens for condensing light to each pixel. I don't need it.

12 is a perspective view showing an exemplary form of a nanopost that may be employed in a color separation lens array according to an exemplary embodiment. Referring to FIG. 12, the nanopost may have a cylindrical shape having a diameter D and a height H. The diameter D and/or the height H may have a value of the sub-wavelength, and the diameter D may vary depending on the position where the nanopost is disposed.

In addition, the nanopost may be formed as a pillar having various cross-sectional shapes. 13A to 13H are plan views showing exemplary shapes of nanoposts that may be employed in a color separation lens array of an image sensor.

13A, the cross-sectional shape of the nanopost may have a circular ring shape having an outer diameter D and an inner diameter Di. The width of the ring, w, may have a sub-wavelength value. 13B, the cross-sectional shape of the nanopost may have an elliptical shape in which the major and minor lengths, Dx, and Dy are different from each other in the first direction (X direction) and the second direction (Y direction). Such a shape may be employed, for example, in the first region 131 and the fourth region 134 corresponding to the green pixel, as mentioned when describing the embodiment of FIG. 5B.

Additionally, the cross-sectional shape of the nanopost is a square shape, a square ring shape, or a cross shape, as shown in Figs. 13C, 13D, and 13F, or, as shown in Figs. 13E and 13G, in the first direction ( X-direction) and the second direction (Y-direction) lengths, Dx, and Dy may have different rectangular shapes or cross-shaped shapes. Such a rectangle or cross shape may be employed in the first region 131 and the fourth region 134 corresponding to the green pixel, as mentioned when describing the embodiment of FIG. 5B.

As another example, the cross-sectional shape of the nanopost may be a shape having a plurality of concave arcs, as shown in FIG. 13H.

14 is a plan view illustrating an arrangement of nanoposts forming a color separation lens array according to another exemplary embodiment.

The color separation lens array 140 has a shape corresponding to the pixel arrangement of the Bayer pattern illustrated in FIG. 2A, and includes a first region 141 corresponding to the green pixel G, and a second region 142 corresponding to the blue pixel B. ), a third region 143 corresponding to the red pixel R, and a fourth region 144 corresponding to the green pixel G. Although not shown, such a unit pattern array may be repeatedly arranged along the first direction (X direction) and the second direction (Y direction). Each region may be divided into a plurality of sub-regions, and a nanopost NP may be disposed at an intersection of the boundaries of the sub-regions. FIG. 14 shows an example in which the number of sub-regions is 9, and nanoposts (NPs) are arranged on the grid points that divide the sub-regions into nine, so that the center of each region 141, 142, 143, 144 The nanoposts (NP) are not arranged in the structure, and four nanoposts (NP) of the same size form the center. The nanoposts (NP) at the periphery are arranged on the boundary line with other regions. The nanoposts (NPs) are indicated by r1 to r9 according to the detailed position in the unit pattern array.

Referring to FIG. 14, the nanoposts r1 disposed at the center of the first region 141 corresponding to the green pixel have a larger cross-sectional area than the nanoposts r5, r6, and r9 disposed at the periphery, and The nanoposts r4 disposed at the center of the corresponding fourth region 144 have a larger cross-sectional area than the nanoposts r7, r8, and r9 disposed at the periphery. The cross-sectional sizes of the nanoposts r1 and r4 disposed in the centers of the first and fourth areas 141 and 144 corresponding to the green pixels are disposed at the center of the second area 142 corresponding to the blue pixels. It may be larger than the cross-sectional size of the nanoposts r2 and the nanoposts r3 disposed in the center of the third region 143 corresponding to the red pixel. In addition, the cross-sectional area of the nanopost r2 disposed in the center of the second region 142 corresponding to the blue pixel is less than the cross-sectional area of the nanopost r3 disposed in the center of the third region 143 corresponding to the red pixel. It can be big.

The nanoposts NP in the second region 142 and the third region 143 may be symmetrically disposed along a first direction (X direction) and a second direction (Y direction), and the first region ( The nanoposts NP of the 141 and the fourth region 144 may be asymmetrically disposed along the first direction (X direction) and the second direction (Y direction). In other words, the nanoposts NP of the second region 142 and the third region 143 corresponding to the blue and red pixels, respectively, are identical in the first direction (X direction) and the second direction (Y direction). It may have a distribution rule, and the nanoposts NPs of the first region 141 and the fourth region 144 corresponding to the green pixels are each other along a first direction (X direction) and a second direction (Y direction). It can have different distribution rules.

Among the nanoposts NP, the cross-sectional area and the first region 141 of the nanoposts r5 positioned at the boundary between the first region 141 and the second region 142 adjacent in the first direction (X direction) The cross-sectional areas of the nanoposts r6 positioned at the boundary between the and the third region 143 adjacent in the second direction (Y direction) are different from each other. In addition, the cross-sectional area of the nanopost r7 positioned at the boundary between the fourth region 144 and the third region 143 adjacent in the first direction (X direction) and the fourth region 144 and the second direction (Y direction) The cross-sectional areas of the nanoposts r8 positioned at the boundary with the second region 142 adjacent to each other in the direction) are different from each other.

On the other hand, the cross-sectional area of the nanopost r5 positioned at the boundary between the first region 141 and the second region 142 adjacent in the first direction (X direction) and the fourth region 144 and the second direction (Y direction) The third region 143 adjacent to the first region 141 and the second direction (Y direction) with the same cross-sectional area of the nanoposts r8 positioned at the boundary with the second region 142 adjacent in the direction) The cross-sectional area of the nanoposts (r6) located at the boundary of and the cross-sectional area of the nanoposts (r7) located at the boundary between the fourth region 144 and the third region 143 adjacent in the first direction (X direction) Is the same.

On the other hand, the first region 141, the second region 142, the third region 143, the fourth region 144, each of the four corners, that is, the nanoposts (r9) arranged at the intersection of the four regions They have the same cross-sectional area.

In this way, in the second region 142 and the third region 143 respectively corresponding to the blue and red pixels, nanoposts NP are arranged in a form of 4-fold symmetry, and In the corresponding first and fourth regions 141 and 144, nanoposts NP are arranged in a form of 2-fold symmetry, and the first region 141 and the fourth region 144 are It is rotated 90 degrees about. This form also appears in the embodiments of FIGS. 16 and 17 to be described later.

15 is a plan view exemplarily showing an arrangement of nanoposts forming a color separation lens array according to another exemplary embodiment.

The color separation lens array 150 has a shape corresponding to the pixel arrangement of the Bayer pattern, and has a first region 151 corresponding to a green pixel, a second region 152 corresponding to a blue pixel, and a third region corresponding to a red pixel ( 153) and a fourth region 154 corresponding to a green pixel may include a quadrant.

Each region may be divided into a plurality of sub-regions, and a nanopost NP may be disposed at an intersection of the boundaries of the sub-regions. 15 is different from the arrangement of the nanostructures of FIG. 14 in that it shows an example in which the number of sub-regions is 16, and nanoposts (NPs) are arranged on the grid points divided into 16 sub-regions, respectively. A nanopost NP is disposed in the center of the regions 151, 152, 153, and 154. The nanoposts (NPs) are indicated by s1 to s11 according to the detailed position in the unit pattern array.

In the embodiment of FIG. 15, a nanopost s1 located in the center of the first region 151 corresponding to a green pixel, and a nanopost s4 located in the center of the fourth region 154 are located at the periphery. ) And may have a cross-sectional area larger than that of the nanoposts NP disposed in the second region 152 corresponding to the blue pixel and the third region 153 corresponding to the red pixel.

In the first region 151, the nanopost s1 having the largest cross-sectional area is disposed in the center, and the nanoposts s10, s5, and s6 whose cross-sectional area gradually decreases toward the periphery are disposed. Also in the fourth region 154, the nanoposts s4 with the largest cross-sectional area are arranged in the center, and the nanoposts s11, s7, and s8 whose cross-sectional areas gradually decrease toward the periphery are arranged. In contrast, in the second region 152, nine nanoposts s2 having the same cross-sectional area are disposed at the center, and nanoposts s5 and s8 having a larger cross-sectional area are disposed at the periphery thereof. Also in the third region 153, nine nanoposts s3 having the same cross-sectional area are disposed in the center, and nanoposts s6 and s7 having a larger cross-sectional area are disposed at the periphery thereof. The nanoposts NP at the periphery of the second and third regions 152 and 153 are arranged on a boundary line with other regions.

In the embodiment of FIG. 15, as in the embodiment of FIG. 14, the nanoposts NP of the second region 152 and the third region 153 are arranged in the first direction (X direction) and the second direction (Y direction). The nanoposts NP of the first region 151 and the fourth region 154 may be disposed symmetrically, and may be asymmetrically disposed along the first direction (X direction) and the second direction (Y direction). I can. In addition, the first region 151, the second region 152, the third region 153, the four corners of each of the fourth region 154, that is, the nanoposts (s9) arranged at a position adjacent to the four regions They have the same cross-sectional area.

16 is a plan view exemplarily showing an arrangement of nanoposts forming a color separation lens array according to another exemplary embodiment.

The color separation lens array 160 has a shape corresponding to the pixel arrangement of the Bayer pattern, and has a first region 161 corresponding to a green pixel, a second region 162 corresponding to a blue pixel, and a third region corresponding to a red pixel ( 163) and a fourth region 164 corresponding to a green pixel may include a quadrant.

Each region may be divided into a plurality of sub-regions, and nanoposts NP may be disposed within the sub-regions. In the color separation lens array 160, each region is divided into nine sub-regions, as in FIG. 14, but there is a difference in that the nanoposts NP are disposed inside the sub-regions rather than at the intersections between the sub-regions. Nanoposts (NPs) are denoted as t1 to t16 according to detailed positions in the unit pattern array.

In the embodiment of FIG. 16, the nanopost t1 located in the center of the first region 161 and the nanopost t4 located in the center of the fourth region 164 are not only nanoposts (NP) located at the periphery thereof. , The cross-sectional size may be larger than that of the nanoposts NP disposed in the second region 162 and the third region 163.

The cross-sectional area of the nanopost t2 disposed in the center of the second area 162 may be larger than the cross-sectional area of the nanopost t3 disposed in the center of the third area 163. In the case of the second region 162, the cross-sectional area of the nanoposts s6 and s10 located in the periphery spaced apart from the center in the first direction (X direction) and the second direction (Y direction) The cross-sectional area is larger than the cross-sectional area, and, on the contrary, the cross-sectional area of the nanoposts t14 located in the periphery spaced diagonally from the center is smaller than the cross-sectional area of the central nanopost t2.

In the case of the third region 163, the cross-sectional area of the central nanopost t3 is the smallest, and the peripheral nanoposts t7, t11, and t15 all have a larger cross-sectional area than the central nanopost t3.

The nanoposts NP of the second region 162 and the third region 163 may be symmetrically disposed along a first direction (X direction) and a second direction (Y direction), and the first region 161 ) And the fourth region 164 may be arranged asymmetrically along the first direction (X direction) and the second direction (Y direction). In other words, the nanoposts NPs in the second region 162 and the third region 163 corresponding to the blue pixel and the red pixel, respectively, are in the first direction (X direction) and the second direction (Y direction). Representing the same distribution rule, the nanoposts (NP) in the first region 161 and the fourth region 164 corresponding to the green pixels are each other along the first direction (X direction) and the second direction (Y direction). Different distribution rules are shown.

In the first region 161, the nanopost t1 in the center, the nanopost t5 adjacent in the first direction (X direction) and the nanopost t9 adjacent in the second direction (Y direction) have different cross-sectional areas. . In the fourth region 164, the nanopost t4 in the center, the nanopost t8 adjacent in the first direction (X direction) and the nanopost t12 adjacent in the second direction (Y direction) have different cross-sectional areas. . In addition, the nanopost t1 in the center of the first region 161 and the nanopost t5 adjacent to the nanopost in the first direction (X direction) have a nanopost t4 in the center of the fourth region 164 and a second direction (Y direction). Direction) has the same cross-sectional area as the nanopost t12 adjacent to the first region 161 and the nanopost t9 adjacent to the second direction (Y direction) and the nanopost t1 at the center of the first region 161 are the fourth region 164 It has the same cross-sectional area as the nanopost t4 in the center and the nanopost t8 adjacent in the first direction (X direction). The nanoposts t13 located adjacent to the four corners of the first region 161 and the nanoposts t16 located adjacent to the four corners of the fourth region 164 have the same cross-sectional area. In this way, the first region 161 and the fourth region 164 are rotated 90 degrees with respect to each other.

In the second region 162, the nanopost t2 in the center and the nanopost t6 adjacent in the first direction (X direction) and the nanopost t10 adjacent in the second direction (Y direction) have the same cross-sectional area. Have. The nanoposts t14 positioned adjacent to the four corners of the second region 162 have the same cross-sectional area.

Also in the case of the third region 163, the nanoposts t3 in the center and the nanoposts t7 adjacent in the first direction (X direction) and the nanoposts t11 adjacent in the second direction (Y direction) are the same. Has a cross-sectional area. The nanoposts t15 located adjacent to the four corners of the third region 163 have the same cross-sectional area.

17 is a plan view illustrating an arrangement of a plurality of nanoposts constituting a color separation lens array according to another exemplary embodiment.

The color separation lens array 170 of the image sensor of this embodiment is an embodiment of the simplest structure. Each of the first region 171 corresponding to the green pixel, the second region 172 corresponding to the blue pixel, the third region 173 corresponding to the red pixel, and the fourth region 174 corresponding to the green pixel. One nanopost (NP) is disposed, the cross-sectional area of the nanopost (NP) provided in the first region 171 and the fourth region 174 is the largest, and the nanopost provided in the second region 172 ( The cross-sectional area of NP) is smaller than the cross-sectional area of the nanoposts NP provided in the first region 171, and the cross-sectional area of the nanoposts NP of the third region 173 is the smallest.

18 is a graph exemplarily showing a spectral distribution of light incident on each of a red pixel (R), a green pixel (G), and a blue pixel (B) of an image sensor including the color separation lens array of FIG. 17.

19A and 19B are cross-sectional views illustrating a schematic structure of a pixel array according to another exemplary embodiment, respectively.

The pixel array 1100a is different from the above-described embodiments of FIGS. 4A and 4B in that a color filter 105 is further disposed between the sensor substrate 110 and the color separation lens array 130. The color filter 105 may be disposed between the sensor substrate 110 and the spacer layer 120.

The pixel array 1100a may further include a transparent dielectric layer 121 protecting the color separation lens array 130. The dielectric layer 121 may be disposed to cover a space between adjacent nanoposts NP and an upper surface of the nanoposts NP. The dielectric layer 121 may be made of a material having a refractive index lower than that of the nanopost NP, for example, the same material as the spacer layer 120.

The color filter 105 has a filter area having a shape corresponding to the pixel arrangement of the Bayer pattern. As shown in FIG. 19A, the green filter area CF1 and the blue filter area CF2 are alternately disposed, and as shown in FIG. 19B, the red filter area CF3 and the green color are separated from each other in the Y direction in the next row. Filter regions CF1 are alternately arranged. Since the color separation lens array 130 diverges and condenses light of different wavelengths to the plurality of light sensing cells 111, 112, 113, and 114, the configuration of the color filter 105 is not an essential component. However, by providing the color filter 105 additionally as described above, color purity may be supplemented, and since the color-separated light to a considerable extent enters the color filter 105, the optical loss is not large.

20 and 21 are graphs showing spectral distributions of light incident on a red pixel (R), a green pixel (G), and a blue pixel (B) of an image sensor as an example. It shows the spectral distribution of an example without a color filter.

The graph of FIG. 20 is a spectrum of the image sensor with the color filter shown in FIGS. 19A and 19B, and the graph of FIG. 21 is a spectrum of the image sensor without the color filter shown in FIGS. 4A and 4B. 20 and 21 are simulation results of an image sensor having a pixel width of about 0.7 μm. When a color filter is provided, the overall amount of light tends to decrease, but all of the color separation performance is improved compared to the comparative example.

The image sensor including the color separation lens array according to the above-described embodiments can be applied to various optical devices such as a camera. For example, FIG. 22 is a conceptual diagram schematically showing a camera according to an embodiment.

Referring to FIG. 22, the camera 2000 according to an embodiment uses an objective lens 2010 to form an optical image by focusing light reflected from an object and an optical image formed by the objective lens 2010 as an electrical image signal. It may include an image sensor 1000 that converts into. The image sensor 1000 includes the above-described color separation lens array. In addition, the camera 2000 further includes a processor 2200 that processes the electrical signal output from the image sensor 1000 into an image signal. The processor 2200 forms an image by performing operations such as noise removal and color interpolation with respect to the color-specific signals output from the image sensor 1000. Although not shown, the camera 2000 may also include an infrared cut filter disposed between the image sensor 1000 and the objective lens 2010, a display panel displaying an image formed by the processor 2200, and the processor 2200. It may further include a memory for storing the formed image data. The camera 2000 may be mounted in, for example, a mobile electronic device such as a mobile phone, a notebook computer, or a tablet PC.

The objective lens 2010 serves to focus an image of a subject outside the camera 2000 on the image sensor 1000. When the image sensor 1000 is accurately positioned on the focal plane of the objective lens 2010, light originating from a point on the subject is collected again to a point on the image sensor 1000 through the objective lens 2010. For example, light starting from a point A on the optical axis OX passes through the objective lens 2010 and then is collected at the center of the image sensor 1000 on the optical axis OX. Light originating from a point (B, C, D) deviating from the optical axis OX crosses the optical axis OX by the objective lens 2010 and is collected at a point in the periphery of the image sensor 1000. For example, in FIG. 22, light originating from a point B above the optical axis OX crosses the optical axis OX and is collected at the lower edge of the image sensor 1000, and is lower than the optical axis OX. The light originating from a point C in is collected at the upper edge of the image sensor 1000 across the optical axis OX. In addition, the light originating from the point D located between the optical axis OX and the point B is collected between the center and the lower edge of the image sensor 1000.

Therefore, the light from each of the different points (A, B, C, D) is at different angles depending on the distance between the points (A, B, C, D) and the optical axis (OX). 1000). The incident angle of light incident on the image sensor 1000 is typically defined as a chief ray angle (CRA). The chief ray refers to a light ray incident on the image sensor 1000 from one point of the subject through the center of the objective lens 2010, and the chief ray angle refers to an angle formed by the chief ray with the optical axis OX. The light originating from the point A on the optical axis OX has a principal ray angle of 0 degrees, and enters the image sensor 1000 perpendicularly. As the starting point is farther from the optical axis OX, the principal ray angle increases.

From the viewpoint of the image sensor 1000, the main ray angle of light incident on the center of the image sensor 1000 is 0 degrees, and the main ray angle of the incident light increases toward the edge of the image sensor 1000. For example, starting from points (B) and (C), the main ray angle of light incident on the edge of the image sensor 1000 is the largest, and starting from point (A) and incident on the center of the image sensor 1000 The main ray angle of light is 0 degrees. In addition, the main ray angle of the light incident between the center and the edge of the image sensor 1000 starting from the point D is less than the main ray angle of the light starting from the points B and C and is greater than 0 degrees.

However, the color separation lens array described above may generally have directionality. In other words, the color separation lens array operates efficiently with respect to light incident in a specific angular range, but when the incident angle is away from the specific angular range, the color separation performance of the color separation lens array deteriorates. Therefore, if all the nanoposts of the color separation lens array have the same arrangement in the entire area of the image sensor 1000, the color separation efficiency is not uniform in the entire area of the image sensor 1000, and the color separation efficiency is not uniform in the area of the image sensor 1000. Accordingly, the color separation efficiency varies. As a result, the quality of an image provided by the camera 2000 may be deteriorated.

Accordingly, the arrangement of the nanoposts of the color separation lens array may be designed differently in consideration of the main ray angle of incident light that varies depending on the position on the image sensor 1000. For example, FIGS. 23A to 23C are schematic plan views showing a change in the arrangement shape of the nanoposts of the color separation lens array according to the position on the image sensor. In particular, FIG. 23A shows the location of the nanoposts NP disposed in the center of the image sensor 1000, and FIG. 23B shows the location of the nanoposts NP disposed between the center and the edge of the image sensor 1000. , FIG. 23C shows the location of the nanoposts NP disposed at the edge of the image sensor 1000. 23A to 23C are not intended to limit a specific arrangement of the nanoposts NP, but are merely for conceptually explaining a change in the relative position of the nanoposts NP according to the position on the image sensor 1000.

23A to 23C, the first, second, third, and fourth regions of the color-separating lens array from the center of the image sensor 1000 to the edge are corresponding pixels or light. It can be located shifted further away from the sensing cells. For example, the positions of the first region, the second region, the third region, and the fourth region of the color separation lens array from the center of the image sensor 1000, the center of the color separation lens array, or the center of the sensor substrate are The positions of the corresponding green pixels, blue pixels, red pixels, and green pixels (or positions of corresponding photosensitive cells) may be matched. Further, as the distance from the center of the image sensor 1000, the center of the color separation lens array, or the center of the sensor substrate, the first area, the second area, the third area, and the fourth area of the color separation lens array are Each of the corresponding green pixels, blue pixels, red pixels, and green pixels may be shifted further away from locations (or locations of corresponding light sensing cells). The degree to which the first region, the second region, the third region, and the fourth region of the color separation lens array are shifted may be determined by a principal ray angle of light incident on the color separation lens array. In particular, the first region, the second region, the third region, and the fourth region of the color separation lens array at the periphery of the image sensor 1000, the periphery of the color separating lens array, or the periphery of the sensor substrate, respectively The first light sensing cell, the second light sensing cell, the third light sensing cell, and the fourth light sensing cell are shifted toward the center of the image sensor 1000.

Hereinafter, for convenience, it is expressed as the center of the image sensor 1000, but since the image sensor 1000, the color separation lens array, and the sensor substrate are disposed facing each other, the center of the image sensor 1000 is also of the color separation lens array. It may mean the center or the center of the sensor substrate. Likewise, hereinafter, the periphery/edge of the image sensor 1000 may mean the periphery/edge of the color separation lens array or the periphery/edge of the sensor substrate.

24 is a cross-sectional view illustrating a schematic structure of a pixel array according to another exemplary embodiment.

Referring to FIG. 24, the pixel array 1100b of the image sensor of this embodiment is different from the above-described embodiments in that it includes a color separation lens array 230 including nanoposts (NPs) stacked in two stages. There is. The nanopost NP may include a first nanopost NP1 disposed on the spacer layer 120 and a second nanopost NP2 disposed on the first nanopost NP1. The second nanopost NP2 may be shifted along the inclination direction of light with respect to the first nanopost NP1. For example, when light incident on the color separation lens array 230 is inclined from right to left, the second nanopost NP2 may be shifted to the right with respect to the first nanopost NP1. Conversely, when light incident on the color separation lens array 230 is inclined from left to right, the second nanopost NP2 may be shifted to the left with respect to the first nanopost NP1.

In addition, when considering the main ray angle of light incident on the image sensor 1000 illustrated in FIG. 22, the second nanopost NP2 is directed toward the center of the image sensor 1000 with respect to the first nanopost NP1. Can be shifted. For example, as the image sensor 1000 moves from the center to the left edge, the second nanopost NP2 is shifted further to the right with respect to the first nanopost NP1, and from the center of the image sensor 1000 to the right edge. Increasingly, the second nanopost NP2 is further shifted to the left with respect to the first nanopost NP1.

Likewise, the third region 233 and the fourth region 234 of the color separation lens array 230 are each corresponding to the red pixel (or the third light sensing cell) and the green pixel (or the fourth light sensing cell). In contrast, it is shifted toward the center of the image sensor 1000. For example, from the center of the image sensor 1000 to the left edge, the third area 233 and the fourth area 234 of the color separation lens array 230 are on the right side of the corresponding green and red pixels, respectively. Is shifted further. Although not shown, the first region and the second region disposed on different end surfaces of the color separation lens array 230 are also corresponding green pixels (or first light sensing cells) and blue pixels (or second light sensing cells). ) Is shifted toward the center of the image sensor 1000.

In particular, the third region 233 and the fourth region 234 of the color separation lens array 230 are located in the center of the third photo-sensing cell 113 and the center of the fourth photo-sensing cell 114 respectively. It can be shifted to condense red light and green light, respectively. The distance s at which the third region 233 and the fourth region 234 of the color separation lens array 230 are shifted may be determined by, for example, Equation 2 below.

In Equation 2, d is the shortest linear distance or distance between the lower surface of the color separation lens array 230 and the upper surface of the sensor substrate 110, and CRA' is the incident angle of light incident on the sensor substrate 110. In addition, CRA' may be determined by Equation 3 below.

In Equation 3, CRA is the incident angle of light incident on the color separation lens array 230, and n is the refractive index of the material disposed between the color separation lens array 230 and the sensor substrate 110. Accordingly, the distance s at which the third region 233 and the fourth region 234 of the color separation lens array 230 are shifted from the corresponding pixels is the incident angle of light incident on the color separation lens array 230 and the color It may be determined by the refractive index of a material disposed between the separation lens array 230 and the sensor substrate 110. If not only the spacer layer 120 but also the color filter 105 is disposed between the color separation lens array 230 and the sensor substrate 110, the incident angle of light incident on the spacer layer 120 and the spacer layer 120 CRA′ may be determined in consideration of the refractive index of ), the incident angle of light incident on the color filter 105 and the refractive index of the color filter 105.

25 is a plan view exemplarily showing a shift form of nanoposts arranged in two dimensions in the color separation lens array applied to the image sensor of the camera shown in FIG. 22, and FIG. 26 is provided with the color separation lens array shown in FIG. Is a cross-sectional view showing a schematic structure of a pixel array.

25 and 26, the first to fourth regions of the color separation lens array 230 in the center C of the image sensor 1000 are shifted with respect to the corresponding pixels (or photosensitive cells). Didn't. In addition, the second nanopost NP2 in the center C of the image sensor 1000 is not shifted with respect to the first nanopost NP1. In addition, the first to fourth regions of the color separation lens array 230 in the peripheral portion P of the image sensor 1000 are shifted toward the central portion C of the image sensor 1000, and the second nanopost NP2 ) Is also shifted toward the center C of the image sensor 1000 with respect to the first nanopost NP1. Accordingly, in the case of the image sensor 1000 employed in the camera 2000 shown in FIG. 22, the total area of the color separation lens array 230 is the total area of the pixel array 1100b of the image sensor 1000 or the sensor substrate It may be smaller than the total area of (110).

On the other hand, in the embodiment of FIG. 24, although the color filter 105 is disposed on the sensor substrate 110, if the color separation lens array 230 has sufficient performance in the peripheral portion P of the image sensor 1000, FIG. 26 As shown in, the color filter 105 may be omitted.

FIG. 27 is a perspective view illustrating an exemplary shape of a nanopost employed in the color separation lens array of the image sensor of FIG. 26. As shown in FIG. 27, the lower first nanoposts NP1 and the upper second nanoposts NP2 may be stacked to be offset from each other. The degree of deviation is indicated by b in FIG. 27, and the size may increase from the central portion C of the image sensor 1000 to the peripheral portion P, that is, along the radial direction. The direction in which the second nanopost NP2 deviates from the first nanopost NP1 becomes a direction from the peripheral portion P to the central portion C. In particular, the degree of shift b may be determined such that light is incident on the center of the upper surface of the second nanopost NP2 and the light is incident on the center of the upper surface of the first nanopost NP1.

In order to manufacture a nanopost (NP) with such a structure, as shown in FIG. 26, the dielectric layer 121 is disposed on the spacer layer 120 to fill the space between the first nanoposts NP1 and A first dielectric layer 121a supporting the post NP2 and a second dielectric layer 121b covering the second nanoposts NP2 may be included. The first dielectric layer 121a and the second dielectric layer 121b may be formed of a material having a refractive index lower than that of a material constituting the first nanopost NP1 and the second nanopost NP2.

Although the structure in which the nanoposts (NP) are stacked in two layers is illustrated, the structure is not limited thereto and may have a structure of three or more layers. For example, FIG. 28 is a cross-sectional view showing a schematic structure of a pixel array according to another exemplary embodiment.

Referring to FIG. 28, a pixel array 1100c of an image sensor includes a color separation lens array 240 including nanoposts NPs stacked in three tiers. The nanopost (NP) is disposed on the first nanopost (NP1) disposed on the spacer layer 120, the second nanopost (NP2) disposed on the first nanopost (NP1), and the second nanopost (NP2) It may include a third nanopost (NP3). The second nanopost (NP2) is shifted toward the center of the image sensor with respect to the first nanopost (NP1), and the third nanopost (NP3) is shifted toward the center of the image sensor with respect to the second nanopost (NP2). do.

In addition, the fourth area 244 of the color separation lens array 240 is shifted toward the center of the image sensor with respect to the corresponding green pixel or the fourth light sensing cell 114, and the third area 243 is It is shifted toward the center of the image sensor with respect to the corresponding red pixel or the third light sensing cell 113.

29A to 29C are graphs showing spectral distributions of light incident on a red pixel, a green pixel, and a blue pixel of the image sensor according to an exemplary embodiment. If not considered, the case where the position of the nanopost is changed in consideration of the change in the principal ray angle, and the case in which the nanopost is configured in two stages in consideration of the change in the principal ray angle. In FIGS. 29A to 29C, the graph indicated by B0 is the spectrum distribution of light incident on the blue pixel when the main ray angle is 0 degrees, and the graph indicated by G0 is the spectrum of light incident on the green pixel when the principal ray angle is 0°. Distribution, and the graph indicated by R0 is the spectral distribution of light incident on the red pixel when the main ray angle is 0 degrees. In addition, the graph indicated by B26 is the spectral distribution of light incident on the blue pixel when the main ray angle is 26 degrees, and the graph indicated by Gb26 is the blue pixel and the green pixel alternately arranged in the first direction when the main ray angle is 26 degrees. The graph indicated by Gr26 is the spectral distribution of light incident on the red pixel and the green pixel alternately arranged in the first direction when the main ray angle is 26 degrees, and the graph indicated by R26 indicates the main ray angle is 0. In the case of degrees, it is the spectral distribution of light incident on the red pixel.

As shown in the graph of FIG. 29A, it can be seen that performance of the color separation lens array for light having a principal ray angle of 26 degrees deteriorates when the change in the principal ray angle is not considered. In addition, as shown in the graph of FIG. 29B, when the nanopost is shifted in consideration of the change of the principal ray angle, the performance of the color separation lens array for light having a principal ray angle of 26 degrees is improved. In addition, as shown in the graph of FIG. 29C, when the nanoposts are configured in two stages together with the shift of the nanoposts, the performance of the color separation lens array for light with a principal ray angle of 26 degrees is further improved, and thus light with a principal ray angle of 0 degrees. The performance of the color separation lens array for

30A and 30B are plan views illustrating a line width change of a nanopost according to a position on an image sensor according to another exemplary embodiment. FIG. 30A shows the line width of the nanoposts NP' of the color separation lens array at the center of the image sensor, and FIG. 30B exemplarily shows the line width of the nanoposts NP′ of the color separation lens array at the periphery of the image sensor. do. In the embodiment shown in FIG. 30B, the position of the nanopost is shifted with respect to the corresponding pixel, and the second nanopost NP2' is shifted with respect to the first nanopost NP1'. ) Has been further changed. The line width change of the nanopost NP' may be determined as shown in Equation 4 below according to the principal ray angle.

In Equation 4, w is the line width of the nanopost NP' at the periphery of the image sensor, and w ₀ is the line width of the nanopost NP at the center of the image sensor. Accordingly, the line width of the nanopost NP' may increase toward the periphery of the image sensor. 30B is an exaggerated view of the line width increase of the nanopost (NP') for convenience. The line width of the nanopost NP' at the edge of the image sensor may increase by about 2.5% to 6.5% compared to the line width at the center of the image sensor.

Here, the line width change is a comparison of the line widths of nanoposts disposed at the same position in the same region among a plurality of first, second, third, and fourth regions of the color separation sensor array. For example, the line width of the nanopost disposed in the center of the first area of the color separation sensor array at the center of the image sensor and the line width of the nanopost disposed in the center of the first area of the color separation sensor array at the periphery of the image sensor. Can be compared. Nanoposts disposed in different regions of the color separation sensor array or nanoposts disposed at different positions within the same region are not subject to line width comparison.

FIG. 31 is a graph exemplarily showing a spectral distribution of light incident on a red pixel, a green pixel, and a blue pixel of the image sensor illustrated in FIG. 30. Comparing the graph of FIG. 31 with the graph of FIG. 29C, when the line width of the nanopost is further changed together with the shift of the nanopost and the two-stage configuration of the nanopost, the performance of the color separation lens array for light with a principal ray angle of 26 degrees. It can be seen that this is further improved.

32 and 33 are plan views showing various shapes of nanoposts used in a color separation lens array according to another exemplary embodiment. As shown in FIGS. 32 and 33, nanoposts having various shapes may be shifted and disposed. For example, as shown in FIG. 32, two-stage stacked nanoposts NP1 and NP2 in a rectangular shape having different sizes from each other may be shifted with respect to each other. In addition, as shown in FIG. 33, two-stage stacked ring-shaped nanoposts (NPa), two-stage stacked circular nanoposts (NPb), and two-stage stacked rectangular nanoposts (NPc) are each of the color separation lens array. Can be shifted relative to each other in the areas of.

34 and 35 are cross-sectional views showing various cross-sectional shapes of nanoposts used in a color separation lens array according to another embodiment. 34 and 35, an inclined surface may be formed on the side of the nanopost. For example, in the color separation lens array 250 illustrated in FIG. 34, an inclined surface is formed on the side of the nanopost in such a manner that the cross-sectional area of the nanopost increases from the bottom to the top. Accordingly, the nanoposts of the color separation lens array 250 have a trapezoidal cross section in which an upper surface is larger than a lower surface. In addition, the color separation lens array 260 illustrated in FIG. 35 has an inclined surface formed on the side of the nanopost in such a manner that the cross-sectional area of the nanopost decreases from the bottom to the top. Accordingly, the nanoposts of the color separation lens array 260 have a trapezoidal cross section in which the lower surface is larger than the upper surface.

The inclinations of the inclined surfaces of the nanoposts respectively disposed in the first region, the second region, the third region, and the fourth region of the color separation lens arrays 250 and 260 may be different from each other. Also, the inclination of the inclined surfaces of the nanoposts located corresponding to the center of the image sensor and the inclination of the inclined surfaces of the nanoposts located corresponding to the peripheral part of the image sensor may be different from each other.

36 is a cross-sectional view illustrating a schematic structure of a pixel array according to another exemplary embodiment.

Referring to FIG. 36, a pixel array 1100d of an image sensor may include a first color separation lens array 280 and a second color separation lens array 290 having a plurality of different arrangements of nanoposts. The second color separation lens array 290 may be disposed on the first color separation lens array 280. The nanoposts of the second color separation lens array 290 do not have a shifted relationship with the nanoposts of the first color separation lens array 280, and the arrangement of the nanoposts of the second color separation lens array 290 May be different from the arrangement shape of the nanoposts of the first color separation lens array 280.

The arrangement of the plurality of nanoposts of the first color separation lens array 280 and the arrangement of the plurality of nanoposts of the second color separation lens array 290 may be determined in consideration of a principal ray angle of light incident on the image sensor. . For example, light incident on the sensor substrate 110 by continuously transmitting the second color separation lens array 290 and the first color separation lens array 280 is efficiently color-separated and condensed irrespective of the incident angle. An arrangement of a plurality of nanoposts of the one color separation lens array 280 and the second color separation lens array 290 may be designed.

As described above, color separation efficiency may be increased by a color separation lens array in which nanoposts of sub wavelengths are arranged in a predetermined rule, and performance of an image sensor employing the same may be improved. The specific forms described are exemplary, and various modifications and combinations thereof are possible. For example, although the wavelength band of visible light has been exemplified, the description is not limited thereto, and other wavelength bands may be separated according to the nanopost arrangement rule. In addition, the number of nanoposts provided in each of the plurality of regions of the nanopost array may be variously changed. The pixel arrangement of the image sensor has been described by exemplifying the Bayer pattern, but is not limited thereto. For example, an arrangement in which red pixels, green pixels, and blue pixels are repeated in one direction in order may be possible, or the CYGM method shown in FIG. 2B An arrangement of or an arrangement of the RGBW method shown in FIG. 2C is also possible. In addition, it may be applied to a pixel arrangement pattern in which a plurality of unit pixels including pixels of two or more colors are repeatedly arranged. The color separation lens array adopts a region division suitable for this pixel arrangement, and a nanopost arrangement rule can be selected for each region.

Until now, it has been described that a color separation lens array is configured through an array of nanoposts formed in a definable shape, but the color separation lens array may also be configured with a free pattern of various types that cannot be defined. For example, FIG. 37 is a conceptual diagram showing a schematic structure and operation of a color separation lens array according to another embodiment.

Referring to FIG. 37, the unit pattern array of the color separation lens array 330 includes first to fourth regions 331, 332, 333, and 334 each having first to fourth microstructures that are distinguished from each other. can do. For example, the first region 331 has a first pattern, the second region 332 has a second pattern patterned in a different shape from the first pattern, and the third region 333 has a first pattern and The third pattern may have a shape different from that of the second pattern, and the fourth region 334 may have a fourth pattern patterned in a shape different from the first to third patterns.

The first to fourth regions 331, 332, 333, and 334 may be arranged on the same plane in the form of, for example, 2×2. Accordingly, the first area 331 and the second area 332 are disposed adjacent to each other in the first direction, and the third area 333 and the fourth area 334 are also disposed adjacent to each other in the first direction. do. In addition, the first region 331 and the third region 333 are disposed adjacent to each other in a second direction perpendicular to the first direction, and the third region 333 and the fourth region 334 are also arranged in the second direction. Are arranged adjacent to each other along the line. The first and fourth regions 331 and 334 are arranged along a diagonal direction, and the second and third regions 333 and 333 are arranged along different diagonal directions.

According to the embodiment, among the incident light incident on the color separation lens array 330, the light of the first wavelength λ1 is condensed in the first target region R1 facing the first region 331 along a vertical direction, and , Light of the second wavelength λ2 is focused on the second target region R2 facing the second region 332 along the vertical direction, and the light of the third wavelength λ3 is focused on the third region 333 It is condensed on the third target region R3 facing along the vertical direction, and the light of the fourth wavelength λ4 is focused on the fourth target region R4 facing the fourth region 334 along the vertical direction, The first to fourth patterns may be determined. Specific first to fourth patterns of the first to fourth regions 331, 332, 333, and 334 are pixels of the image sensor to which the color separation lens array 330 is applied. It can be designed in various ways according to the arrangement and color characteristics.

For example, when the color separation lens array 330 is applied to the Bayer pattern type image sensor shown in FIG. 2A, the first region 331 and the fourth region 334 face the green pixel G. The second region 332 may be disposed to face the blue pixel B, and the third region 333 may be disposed to face the red pixel R. In addition, the first wavelength light λ1 and the fourth wavelength light λ4 may be green light, the second wavelength light λ2 may be blue light, and the third wavelength light λ3 may be red light.

38 is a plan view illustrating a unit pattern array of a color separation lens array that can be applied to a Bayer pattern type image sensor. Referring to FIG. 38, a first region 331 facing the green pixel G includes a first dielectric 331a forming a first pattern and a second dielectric 331b filled between the first dielectric 331a. Includes. The second region 332 facing the blue pixel B includes a first dielectric 332a forming a second pattern and a second dielectric 332b filled between the first dielectric 332a, and the red pixel ( The third region 333 facing R) includes a first dielectric 333a forming a third pattern and a second dielectric 333b filled between the first dielectric 333a, and is formed in the green pixel G. The facing fourth region 334 includes a first dielectric 334a forming a fourth pattern and a second dielectric 334b filled between the first dielectric 334a.

The first region 331 and the second region 332 both face the green pixel and thus have the same shape, but their rotation directions may be different. For example, as shown in FIG. 38, the pattern of the fourth region 334 may have a shape in which the pattern of the first region 331 is rotated by 90 degrees. This difference may be determined according to the arrangement of adjacent pixels. 38, blue pixels B are disposed on the left and right sides of the green pixel G facing the first area 331, and red pixels B are disposed on the left and right sides of the green pixel G facing the fourth area 334. In the difference in which R) is arranged, a pattern arranged in a different direction of rotation may be formed as described above.

All of the first dielectrics 331a, 332a, 333a, and 334a may be made of the same material, and all of the second dielectrics 331b, 332b, 333b, and 334b may be made of the same material. For example, the first dielectric 331a, 332a, 333a, 334a may be made of a dielectric material having a high refractive index, such as TiO2, GaN, SiN3, ZnS, ZnSe, Si3N4, etc., and having a low absorption rate in the visible light band. The dielectrics 331b, 332b, 333b, and 334b may be made of a dielectric material having a low refractive index, such as air, SiO2, and silanol-based spin on glass (SOG), and having a low absorption rate in the visible light band. . When the second dielectrics 331b, 332b, 333b, and 334b are made of air, the color separation lens array 330 shown in FIG. 38 can be formed simply by etching the first dielectrics 331a, 332a, 333a, and 334a. have.

39 is a cross-sectional view illustrating a vertical cross section of the unit pattern array shown in FIG. 38 taken along the AA′ line (X direction), and FIG. 40 is a cross-sectional view illustrating the unit pattern array shown in FIG. It is a cross-sectional view showing a vertical cross section cut along the direction) as an example.

39 and 40, the first dielectrics 331a, 332a, 333a, and 334a and the second dielectrics 331b, 332b, 333b, and 334b may extend in parallel in a vertical direction. The shape of the vertical cross section shown in FIGS. 39 and 40 is exemplary, and the shape of the vertical cross section of the first to fourth regions 331, 332, 333, and 334 varies according to the positions of the AA' line and the BB' line. I can. For example, as the AA' line moves along the Y direction, the shape of the vertical section shown in Fig. 39 changes, and as the BB' line moves along the X direction, the shape of the vertical section shown in Fig. 40 changes. It will change. Regardless of the change in the shape of the vertical section, the first dielectrics 331a, 332a, 333a, 334a and the second dielectrics 331b, 332b in all vertical sections of the first to fourth regions 331, 332, 333, 334 , 333b, 334b) may exist together.

41 is a plan view illustrating an arrangement of a color separation lens array including a plurality of unit pattern arrays illustrated in FIG. 38. As shown in FIG. 41, the color separation lens array 330 may have a form in which a 2×2 unit pattern array shown in FIG. 38 is repeatedly two-dimensionally arranged.

In the color separation lens array 330 applied to the Bayer pattern type image sensor, the first to fourth patterns of the first to fourth regions 331, 332, 333, and 334 may have a predetermined rule. For example, FIG. 42A exemplarily shows a pattern of the first region 331 of the unit pattern array shown in FIG. 38, and FIG. 42B exemplarily shows a pixel of an image sensor corresponding thereto and a pixel around it. Referring to FIG. 42B, a blue pixel B is disposed in a left-right direction of a green pixel G corresponding to the first region 331 and a red pixel R is disposed in a vertical direction. Green pixels corresponding to the fourth region 334 are disposed in a diagonal direction of the green pixel G corresponding to the first region 331, and are not shown in FIG. 42B. Therefore, among the transmitted light that has passed through the first region 331, in order to obtain the same optical effect as the blue light proceeds in the left-right direction of the first region 331 and the red light proceeds in the vertical direction of the first region 331, The first pattern of the first region 331 may have a 2-fold symmetry. For example, as shown in FIG. 42A, the first pattern of the first region 331 is symmetrical to the first axis (I) along the Y direction and to the second axis (II) along the X direction. I can.

43A is an exemplary view of the shape of the second region 332 in the unit pattern array illustrated in FIG. 38, and FIG. 43B is an exemplary view of a pixel of an image sensor corresponding thereto and a pixel surrounding it. Referring to FIG. 43B, green pixels G are disposed in the left-right direction and the vertical direction of the blue pixel B corresponding to the second region 332. In addition, red pixels R are disposed in two diagonal directions intersecting. Therefore, among the transmitted light that has passed through the second region 332, the green light proceeds in the left and right directions and the vertical direction of the second region 332, and the red light has the same optical effect as proceeding in the diagonal direction of the second region 332. To obtain, the second pattern of the second region 332 may have a 4-fold symmetry. For example, as shown in FIG. 43A, the second pattern of the second region 332 is symmetrical to the first axis (I) along the Y direction, and is symmetrical to the second axis (II) along the X direction. , It may be symmetrical to the third axis (III) and the fourth axis (IV) along the diagonal direction.

44A is an exemplary view of the shape of the third area 333 of the unit pattern array illustrated in FIG. 38, and FIG. 44B is an exemplary view showing a pixel of an image sensor corresponding thereto and pixels surrounding the same. Referring to FIG. 44B, green pixels G are disposed in the left-right direction and the vertical direction of the red pixel R corresponding to the third area 333. In addition, blue pixels B are disposed in two diagonal directions intersecting. Therefore, among the transmitted light that has passed through the third area 333, the green light proceeds in the left and right directions and the vertical direction of the third area 333, and the blue light has the same optical effect as the diagonal direction of the third area 333. To obtain, the third pattern of the third region 333 may be four-way symmetric. For example, as shown in FIG. 44A, the third pattern of the third region 333 is symmetrical to the first axis (I) along the Y direction, and is symmetrical to the second axis (II) along the X direction. , It may be symmetrical to the third axis (III) and the fourth axis (IV) along the diagonal direction.

FIG. 45A exemplarily shows the shape of the fourth region 334 of the unit pattern array shown in FIG. 38, and FIG. 45B exemplarily shows the pixels of the image sensor and surrounding pixels corresponding thereto. Referring to FIG. 45B, the red pixel R is disposed in the left and right direction of the green pixel G corresponding to the fourth region 334 and the blue pixel B is disposed in the vertical direction. Green pixels corresponding to the first area 331 are arranged in a diagonal direction, and are not shown in FIG. 45B. Therefore, among the transmitted light that has passed through the fourth region 334, in order to obtain the same optical effect as the red light proceeds in the left and right direction of the fourth region 334 and the blue light proceeds in the vertical direction of the fourth region 401, The fourth pattern of the fourth region 334 may be two-way symmetric. For example, as shown in FIG. 45A, the fourth pattern of the fourth region 334 may be symmetrical to the first axis (I) along the Y direction and symmetrical to the second axis (II) along the X direction. . Also, the pixel arrangement shown in FIG. 45B is rotated by 90 degrees with respect to the pixel arrangement shown in FIG. 42B. Accordingly, the fourth pattern of the fourth region 334 may have the same shape as rotated 90 degrees with respect to the first pattern of the first region 331.

In the color separation lens array 330 applied to the Bayer pattern type image sensor, as another rule of the first to fourth patterns of the first to fourth regions 331, 332, 333, 334, a color separation lens array The first to fourth patterns of the first to fourth regions 331, 332, 333, and 334 may be designed so that blue light, green light, and red light transmitted through 330 have a predetermined target phase distribution. For example, a first region adjacent to the second region 332 and forming a phase in which blue light transmitted through the color separation lens array 330 is condensed to the position of the blue pixel B corresponding to the second region 332 First to fourth patterns of the first to fourth regions 331, 332, 333, and 334 may be determined so as to form a phase that does not advance to positions corresponding to the 331 and the fourth regions 334 .

In addition, a phase in which green light transmitted through the color separation lens array 330 is condensed to the positions of the green pixels G corresponding to the first region 331 and the fourth region 334 is formed, and the first region 331 And the first to fourth regions 331, 332, 333, and 334 to form a phase that does not proceed to positions corresponding to the second region 332 and the third region 333 adjacent to the fourth region 334. ) Of the first to fourth patterns may be determined.

In addition, a phase in which the red light transmitted through the color separation lens array 330 is condensed to the red pixel R corresponding to the third region 333 is formed, and the first region 331 adjacent to the third region 333 is formed. First to fourth patterns of the first to fourth regions 331, 332, 333 and 334 may be determined to form a phase that does not proceed to a position corresponding to the fourth region 334.

Since the target phase distribution to be implemented by the color separation lens array 330 is the same as that described for the color separation lens array 130 described above, a detailed description will be omitted. According to the first to fourth patterns of the first to fourth regions 331, 332, 333, and 334, the color separation lens array 330 is shown in FIGS. 6A to 6D, 7A to 7D, and 8A to 8D. It can do the same thing as described above.

The pattern of the color separation lens array 330 that satisfies the phase distribution as described above can be automatically designed through various computer simulations. For example, using a nature-inspired algorithm such as genetic algorithm, particle swarm optimization algorithm, ant colony optimization, or adjoint optimization ) The pattern of the first to fourth regions 331, 332, 333, and 334 may be optimized through an algorithm-based reverse engineering method.

For the design of the color separation lens array 330, the first to fourth regions 331, 332, and 333, while evaluating the performance of the candidate color separation lens array using evaluation factors such as color separation spectrum, light efficiency, and signal-to-noise ratio. The first to fourth patterns of 334) may be optimized. For example, after determining a target numerical value for each evaluation element in advance, the first to fourth areas 331, 332, and 333 are minimized by minimizing the sum of the difference between the target numerical values and the plurality of evaluation elements. , 334) of the first to fourth patterns may be optimized. Alternatively, performance may be indexed for each evaluation element, and first to fourth patterns of the first to fourth regions 331, 332, 333, and 334 may be optimized so that a value representing the performance is maximized.

The color separation lens array 330 shown in FIG. 38 is only an example, and the size, thickness, and color separation lens of the first to fourth regions 331, 332, 333, 334 of the color separation lens array 330 According to the color characteristics of the image sensor to which the array 330 is applied, the pixel pitch, the distance between the color separation lens array 330 and the image sensor, the incident angle of incident light, etc., various types of color separation lens arrays 330 ) Can be obtained. For example, FIG. 46 is a plan view showing an exemplary shape of a unit pattern array of a color separation lens array according to another embodiment that can be applied to a Bayer pattern type image sensor, and FIG. 47 is a view showing a Bayer pattern type image sensor. It is a plan view exemplarily showing a shape of a unit pattern array of a color separation lens array according to another embodiment that can be applied.

Each of the first to fourth areas 331, 332, 333, and 334 shown in FIG. 38 is optimized in a digitized binary form in a 14×14 rectangular arrangement, and the first to fourth areas 331 shown in FIG. 46 , 332, 333, and 334), each was optimized in a digitized binary form in a 16×16 rectangular array. Accordingly, the unit pattern array of the color separation lens array 330 shown in FIG. 38 has a shape consisting of a 28×28 rectangular array, and the unit pattern array of the color separation lens shown in FIG. 46 is a 32×32 rectangular array. It has a form consisting of. In this case, the shape of the vertical cross section of the first to fourth regions 331, 332, 333, 334 shown in FIGS. 39 and 40 is as the AA' line moves along the Y direction or the BB' line moves in the X direction. As it moves along, it changes discontinuously.

Alternatively, each of the first to fourth regions 331, 332, 333, and 334 shown in FIG. 47 may be optimized in the form of a continuous curve that is not digitized. In this case, the shape of the vertical cross section of the first to fourth regions 331, 332, 333, 334 shown in FIGS. 39 and 40 is as the AA' line moves along the Y direction or the BB' line moves in the X direction. It changes continuously as it moves along.

48A and 48B are schematic cross-sectional views of different cross-sections of a pixel array of an image sensor employing a color separation lens array. 48A and 48B, the pixel array 1100e of the image sensor may include a sensor substrate 110, a spacer layer 120, and a color separation lens array 330. The first region 331 of the color separation lens array 330 is disposed corresponding to the first light sensing cell 111 of the sensor substrate 110, and the second region 332 of the color separation lens array 330 is It is disposed corresponding to the second light sensing cell 112 of the sensor substrate 110. In addition, in the second region 332 of the color separation lens array 330, the sensor substrate 110 is disposed to correspond to the second light sensing cell 112, and the fourth region 334 of the color separation lens array 330 ) Is disposed corresponding to the fourth light sensing cell 114 of the sensor substrate 110. Although not shown in FIGS. 48A and 48B, a color filter may be further disposed between the sensor substrate 110 and the spacer layer 120. The thickness of the spacer layer is determined according to a predetermined propagation distance requirement for condensing light of different wavelengths separated by the color separation lens array 330 onto a corresponding light sensing cell as described above.

The specific patterns of the color separation lens array 330 described so far are merely exemplary, and various modifications thereof are possible. For example, according to different pattern shapes of the first to fourth regions 331, 332, 333, and 334 of the color separation lens array 330, wavelength bands other than visible light may be separated. Also, the number of color separation patterns constituting the unit pattern array of the color separation lens array 330 may be variously changed according to an application example of the color separation lens array 330. The pixel arrangement of the image sensor has been described by exemplifying the Bayer pattern, but is not limited thereto, and may also be applied to the pixel arrangement shown in FIGS. 2B and 2C. A pattern suitable for this pixel arrangement may be determined by adopting regions of the color separation lens array 330 and using the above-described optimization method for each region.

49 is a plan view illustrating a color separation lens array according to another exemplary embodiment. Referring to FIG. 49, the color separation lens array 340 may include a plurality of two-dimensional array of unit patterns indicated by thick lines. Each unit pattern array may be arranged in a 2×2 dimensional shape including the first area 341, the second area 342, the third area 343, and the fourth area 344. When looking at the overall configuration of the color separation lens array 340, the first regions 341 and the second regions 342 are alternately arranged in the horizontal direction within one row, and the third region in the other row. The regions 343 and the fourth regions 344 are alternately arranged along the horizontal direction. In addition, the first region 341 and the third region 343 are alternately arranged in the vertical direction in one column, and the second region 342 and the fourth region 344 are arranged in another column. They are arranged alternately along the longitudinal direction.

In addition, the color separation lens array 340 may further include a plurality of first to fourth regions 341, 342, 343, and 344 that do not belong to any unit pattern array. The first to fourth regions 341, 342, 343, and 344 that do not belong to any unit pattern array may be arranged along the edge of the color separation lens array 340. In other words, a plurality of second regions 342 and a plurality of fourth regions 344 constituting one column are additionally arranged on the left edge of the color separation lens array 340, and one column is formed on the right edge. A plurality of first regions 341 and a plurality of third regions 343 are additionally arranged, and a plurality of third regions 343 and a plurality of fourth regions 344 constituting one row at the upper edge. ) May be additionally arranged, and a plurality of first regions 341 and a plurality of second regions 342 constituting one row may be additionally arranged at the lower edge.

50 is a vertical cross-section of the color separation lens array 340 shown in FIG. 49 taken along a line C-C'. Referring to FIG. 50, the color separation lens array 340 is disposed to protrude in a horizontal direction with respect to the edge of the sensor substrate 110 and does not face any light sensing cells of the sensor substrate 110 in the vertical direction. A first region 341 and a plurality of second regions 342 may be included. Although not all shown in FIG. 50, in FIG. 50, the plurality of first to fourth regions 341, 342, 343, and 344 that do not belong to any unit pattern array are all in a horizontal direction with respect to the edge of the sensor substrate 110. It is arranged to protrude and does not face any light sensing cells in the vertical direction.

As described in FIGS. 6A to 6D, 7A to 7D, and 8A to 8D, the photosensitive cell is not only a region of the color separation lens array 340 corresponding to the vertical, but also a plurality of other surrounding regions. It also receives light from the realm. Therefore, in the absence of the first to fourth regions 341, 342, 343, and 344 added along the edge of the color separation lens array 340, the light sensing cells arranged along the edge of the sensor substrate 110 The amount of incident light is reduced, and color purity may also decrease. By further arranging the first to fourth regions 341, 342, 343, and 344 along the edge of the color separation lens array 340, the sensor substrate ( Light may be provided in the same manner as the light sensing cells arranged on the inside of 110). 49 and 50 may also be applied to a color separation lens array including an arrangement of a plurality of nanoposts described above.

Meanwhile, when applied to the camera 2000 illustrated in FIG. 22, the shape of the plurality of unit pattern arrays of the color separation lens array may be designed differently in consideration of the principal ray angle of incident light. For example, FIG. 51 is a plan view illustrating an exemplary arrangement of a plurality of unit pattern arrays of a color separation lens array according to another exemplary embodiment. Referring to FIG. 51, the color separation lens array 350 may include a plurality of different unit pattern arrays 350a to 350i having different tiles according to positions on the image sensor. For example, the first region of each of the unit pattern arrays 350a to 350i through the above-described optimization algorithm in consideration of the principal ray angle of incident light incident on the image sensor on which the unit pattern arrays 350a to 350i are disposed. The pattern of the fourth area may be determined. When the principal ray angle of light incident on the center of the image sensor is 0 degrees and the principal ray angle of the incident light increases toward the edge of the image sensor, the patterns of the first to fourth regions of the unit pattern arrays 350a to 350i are the image sensor. It may change gradually from the unit pattern array 350e disposed at the center of the image sensor toward the unit pattern arrays 350a, 350b, 350c, 350d, 350f, 350g, 350h, and 350i disposed at the edge of the image sensor.

In addition, two different color separation lens arrays may be stacked in a two-layer structure in order to obtain a constant color separation efficiency regardless of a change in the main ray angle of incident light that varies depending on the position on the image sensor. For example, FIG. 52 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor according to another exemplary embodiment. Referring to FIG. 52, the pixel array 1100f of the image sensor includes a first color separation lens array 360 disposed on the spacer layer 120 and a second color separation lens disposed on the first color separation lens array 360. An array 370 may be included.

The first color separation lens array 360 is disposed to face the first region 361 and the second photosensitive cell 112 along the vertical direction to face the first photosensitive cell 111 A second area 362 may be included. Although only the first region 361 and the second region 362 are shown in the cross-sectional view of FIG. 52, the first color separation lens array 360 may further include a third region and a fourth region at different cross-sectional positions. The second color separation lens array 370 is disposed to face the first region 371 and the second light sensing cell 112 along the vertical direction to face the first light sensing cell 111. The second area 372 may be included. Accordingly, the first region 361 and the second region 362 of the first color separation lens array 360 are respectively formed in the first region 371 and the second region of the second color separation lens array 370 along a vertical direction. It may be disposed facing the region 372. In addition, the second color separation lens array 370 may also further include a third region and a fourth region.

The first area 361 and the second area 362 of the first color separation lens array 360 may have different patterns, and the first area 371 of the second color separation lens array 370 The and second regions 372 may also have different patterns. In addition, the first region 361 of the first color separation lens array 360 has a pattern of a different shape from the first region 371 and the second region 372 of the second color separation lens array 370, The second area 362 of the first color separation lens array 360 may have a pattern different from that of the first area 371 and the second area 372 of the second color separation lens array 370.

In this structure, light incident on the sensor substrate 110 by successively transmitting the second color separation lens array 370 and the first color separation lens array 360 is effectively color-separated regardless of the angle of incidence. Patterns of the separation lens array 370 and the first color separation lens array 360 may be designed. For example, the second color separation lens array 370 may have a different shape according to a position on the image sensor, and may change the incident light traveling direction to be substantially parallel to the surface normal of the first color separation lens array 360. In this case, the pattern of the first color separation lens array 360 may be constant regardless of the position on the image sensor. Alternatively, the pattern of the first color separation lens array 360 and the pattern of the second color separation lens array 370 may be shifted from each other along a direction in which light travels.

Since the image sensor according to the above-described embodiments hardly loses light due to the color filter, a sufficient amount of light can be provided to the pixel even if the size of the pixel is reduced. Therefore, it is possible to manufacture an ultra-high resolution, ultra-small, high-sensitivity image sensor having hundreds of millions of pixels or more. Such an ultra-high resolution, ultra-small, high-sensitivity image sensor may be employed in various high-performance optical devices or high-performance electronic devices. For example, such electronic devices include, for example, smart phones, mobile phones, mobile phones, personal digital assistants (PDAs), laptops, PCs, various portable devices, home appliances, security cameras, medical cameras, and automobiles. , Internet of Things (IoT), other mobile or non-mobile computing devices, but is not limited thereto.

53 is a schematic block diagram of an electronic device including an image sensor according to embodiments. The electronic device includes an image sensor 1000, a processor 2200, a memory 2300, a display 2400, and a bus 2500. The image sensor 1000 acquires image information on an external subject under the control of the processor 2200 and provides it to the processor 2200. The processor 2200 may store the image information provided from the image sensor 1000 in the memory 2300 through the bus 2500, and output the image information stored in the memory 2300 to the display 2400 to be displayed to the user. have. Also, the processor 2200 may perform various image processing on image information provided from the image sensor 1000.

54 to 64 show various examples of electronic devices to which an image sensor according to embodiments is applied.

The image sensor according to the embodiments may be applied to various multimedia devices having an image capturing function. For example, the image sensor may be applied to the camera 2000 shown in FIG. 54. The camera 2000 may be a digital camera or a digital camcorder.

Referring to FIG. 55, the camera 2000 may include an imaging unit 2100, an image sensor 1000, and a processor 2200.

The imaging unit 2100 forms an optical image by focusing light reflected from the subject OBJ. The imaging unit 2100 may include an objective lens 2010, a lens driving unit 2120, a diaphragm 2130, and a diaphragm driving unit 2140. In FIG. 55, only one lens is representatively displayed for convenience, but the objective lens 2010 may actually include a plurality of lenses having different sizes and shapes. The lens driver 2120 may communicate information on focus detection with the processor 2200 and may adjust the position of the objective lens 2010 according to a control signal provided from the processor 2200. The lens driver 1120 may move the objective lens 2010 to adjust the distance between the objective lens 2010 and the object OBJ, or may adjust the positions of individual lenses in the objective lens 2010. The focus on the subject OBJ may be adjusted by the lens driver 2120 driving the objective lens 2010. The camera 2000 may have an auto focus function.

The iris driver 2140 may communicate information on the amount of light with the processor 2200 and may adjust the iris 2130 according to a control signal provided from the processor 2200. For example, the aperture driver 2140 may increase or decrease the aperture of the aperture 2130 according to the amount of light entering the camera 2000 through the objective lens 2010, and the aperture 2130 may be opened. You can adjust the time.

The image sensor 1000 may generate an electrical image signal based on the intensity of incident light. The image sensor 1000 may include a pixel array 1100, a timing controller 1010, and an output circuit 1030. Although not shown in FIG. 55, the image sensor 1000 may further include a row decoder shown in FIG. 1. Light transmitted through the objective lens 2010 and the aperture 2130 may form an image of the object OBJ on the light-receiving surface of the pixel array 1100. The pixel array 1100 may be a CCD or CMOS that converts optical signals into electrical signals. The pixel array 1100 may include additional pixels for performing an AF function or a distance measurement function. Also, the pixel array 1100 may include the above-described color separation lens array.

The processor 2200 may control the overall operation of the camera 2000 and may have an image processing function. For example, the processor 2200 may provide a control signal for the operation of each component to the lens driver 2120, the aperture driver 2140, the timing controller 1010, and the like.

Image sensors according to embodiments are a mobile phone or smart phone 3000 shown in FIG. 56, a tablet or smart tablet 3100 shown in FIG. 57, a notebook computer 3200 shown in FIG. 58, and shown in FIG. 59 It can be applied to the TV or smart television (3300). For example, the smart phone 3000 or the smart tablet 3100 may include a plurality of high-resolution cameras each equipped with a high-resolution image sensor. Using high-resolution cameras, depth information of subjects in an image can be extracted, out-focusing of an image can be adjusted, or subjects in an image can be automatically identified.

In addition, the image sensor is applied to the smart refrigerator 3400 shown in FIG. 60, the security camera 3500 shown in FIG. 61, the robot 3600 shown in FIG. 62, or the medical camera 3700 shown in FIG. 63. I can. For example, the smart refrigerator 3400 may automatically recognize food in the refrigerator using an image sensor, and inform the user of the existence of a specific food, the type of food stocked or released, and the like to the user through the smartphone. In addition, the security camera 3500 may provide an ultra-high resolution image, and may use high sensitivity to recognize an object or person in the image even in a dark environment. The robot 3600 may be input at a disaster or industrial site that cannot be directly accessed by humans to provide a high-resolution image. The medical camera 3700 can provide a high-resolution image for diagnosis or surgery, and can dynamically adjust a field of view.

Also, the image sensor may be applied to the vehicle 3800 as shown in FIG. 64. The vehicle 3800 may include a plurality of vehicle cameras 3810, 3820, 3830, and 3840 arranged at various locations, and each vehicle camera 3810, 3820, 3830, and 3840 uses an image sensor according to an embodiment. Can include. The vehicle 3800 may provide a variety of information about the interior or surroundings of the vehicle 3800 to the driver using a plurality of vehicle cameras 3810, 3820, 3830, and 3840, and automatically recognizes objects or people in the image. It can provide information necessary for autonomous driving.

The image sensor having the above-described color separation lens array and the electronic device including the same have been described with reference to the embodiment shown in the drawings, but this is only exemplary, and various modifications thereof are made to those of ordinary skill in the art. And it will be appreciated that other equivalent embodiments are possible. Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the rights is indicated in the claims rather than the above description, and all differences within the scope equivalent thereto should be construed as being included in the scope of the rights.

105.....color filter
110.....sensor board
111, 112, 113, 114.....light sensing cell
120.....spacer layer
121.....dielectric layer
130, 140, 150, 160, 170.....color-separated lens array
131, 141, 151, 161, 171.....First area
132, 142, 152, 162, 172.....Second area
133, 143, 153, 163, 173.....3rd area
134, 144, 154, 164, 174.....4th area
1000.....image sensor
1010.....Timing controller
1020.....low decoder
1030.....output circuit
1100.....pixel array

Claims (29)

A sensor substrate including a plurality of first light sensing cells and a plurality of second light sensing cells for sensing light: And
A plurality of first regions each corresponding to the plurality of first light sensing cells and having a first microstructure, and each corresponding to the plurality of second light sensing cells and having a second microstructure different from the first microstructure. Including; a color separation lens array having a plurality of second regions,
In the first microstructure and the second microstructure, light having a first wavelength and light having a second wavelength different from among incident light incident on the color separation lens array are diverged in different directions, respectively. 2 A phase distribution condensed by the light sensing cell is formed at a position passing through the first region and the second region,
The positions of the first and second regions in the center of the color separation lens array coincide with the positions of the first and second light sensing cells respectively corresponding thereto, and the first region and the second region are located at the periphery of the color separation lens array. The positions of the first region and the second region are shifted toward the center of the color separation lens array with respect to the first and second light sensing cells corresponding thereto, respectively. The method of claim 1,
The degree to which the first region and the second region at the periphery of the color separation lens array are shifted with respect to the corresponding first and second light sensing cells, respectively, increases as the distance from the center of the color separation lens array increases. Growing, image sensor. The method of claim 1,
The distance s at which the first and second regions are shifted with respect to the corresponding first and second photosensitive cells, respectively, is

Wherein d is the shortest linear distance between the lower surface of the color separation lens array and the upper surface of the sensor substrate, and CRA′ is the incident angle of light incident on the sensor substrate. The method of claim 1,
In the first and second microstructures, at a position immediately after passing through the color separation lens array, light of a first wavelength is 2Nπ at the center of the first photosensitive cell, and at the center of the second photosensitive cell. An image sensor that forms a phase distribution of (2N-1)π, where N is an integer greater than 0. The method of claim 4,
In the first microstructure and the second microstructure, at a position immediately after passing through the color separation lens array, light of a second wavelength is (2M-1)π at the center of the first light sensing cell, and the second light An image sensor that forms a phase distribution of 2Mπ in the center of the sensing cell, and M is an integer greater than 0. The method of claim 1,
The image sensor further comprising a spacer layer disposed between the sensor substrate and the color separation lens array to form a distance between the sensor substrate and the color separation lens array. The method of claim 6,
When the theoretical thickness of the spacer layer is h _t , and the pitch of each of the first and second light sensing cells is p, the thickness h of the spacer layer is h _t -p ≤ h ≤ h _t -p ,
The theoretical thickness of the spacer layer is a focal length of the color separation lens array at a center wavelength of a wavelength band of incident light color-separated by the color separation lens array. The method of claim 7,
When the refractive index of the spacer layer is n and the center wavelength of the wavelength band of light color-separated by the color separation lens array is λ ₀ , the theoretical thickness h _t of the spacer layer is the following equation:

Represented as, the image sensor. The method of claim 1,
The sensor substrate further includes a plurality of third light sensing cells and a plurality of fourth light sensing cells for sensing light,
The color separation lens array corresponds to each of the plurality of third light sensing cells and includes a plurality of third regions having a third microstructure different from the first and second microstructures, and each of the plurality of fourth photosensitive cells. A plurality of fourth regions corresponding to and having a fourth microstructure different from the first to third microstructures,
Each of the first region, the second region, the third region, and the fourth region are each arranged along four quadrants. The method of claim 9,
Positions of the first, second, third, and fourth regions of the color separation lens array in the center of the image sensor are respectively corresponding to the first light sensing cell, the second light sensing cell, and the third light. It matches the position of the sensing cell and the fourth light sensing cell,
At the periphery of the image sensor, the first, second, third, and fourth regions of the color separation lens array are respectively corresponding to a first light sensing cell, a second light sensing cell, and a third light sensing cell. , And a fourth light sensing cell that is shifted toward the center of the image sensor. The method of claim 10,
The first, second, third, and fourth regions of the color separation lens array at the periphery of the image sensor respectively correspond to a first light sensing cell, a second light sensing cell, and a third light sensing cell. , And a degree of shifting with respect to the fourth light sensing cell increases as the distance from the center of the image sensor increases. The method of claim 9,
In the first to fourth microstructures, light having different first wavelengths to third wavelengths among incident light incident on the color separation lens array is diverged in different directions, so that light of the first wavelength is converted into the first light. The first phase distribution in which light of a sensing cell and the fourth light sensing cell is condensed, light of a second wavelength is condensed on the second light sensing cell, and light of a third wavelength is condensed to the third light sensing cell. An image sensor formed at a position passing through the region to the fourth region. The method of claim 12,
The first wavelength is green light, the second wavelength is blue light, and the third wavelength is red light. The method of claim 12,
The first to fourth microstructures are:
At a position immediately after passing through the color separation lens array, light of a first wavelength is 2Nπ at the center of the first photo-sensing cell and the center of the fourth photo-sensing cell, and the center of the second photo-sensing cell and the third Form a phase distribution of (2N-1)π at the center of the light sensing cell,
At a position immediately after passing through the color separation lens array, light of a second wavelength is (2M-1)π at the center of the first photosensitive cell and the center of the fourth photosensitive cell, 2Mπ at the center and a phase distribution larger than (2M-2)π and smaller than (2M-1)π at the center of the third light sensing cell,
At the position immediately after passing through the color separation lens array, the light of the third wavelength is (2L-1)π at the center of the first photosensitive cell and the center of the fourth photosensitive cell, 2Lπ at the center, larger than (2L-2)π and smaller than (2L-1)π at the center of the second light sensing cell, and N, M, and L are integers greater than 0. The method of claim 9,
The first to fourth microstructures of the first to fourth regions include a plurality of nanoposts, and the first to fourth regions have different shapes, sizes, and arrangements of the nanoposts. , Image sensor. The method of claim 15,
The image sensor has a pixel arrangement structure in which a plurality of unit pixels including a red pixel, a green pixel, and a blue pixel are repeatedly arranged,
The image sensor, wherein the nanoposts provided in a region corresponding to a green pixel among the first to fourth regions have different distribution rules along a first direction and a second direction perpendicular to the first direction. The method of claim 16,
The image sensor, wherein the nanoposts provided in regions corresponding to blue pixels and red pixels among the first to fourth regions have symmetrical distribution rules along the first and second directions. The method of claim 15,
Each of the plurality of nanoposts includes a first nanopost and a second nanopost stacked on the first nanopost,
The position of the second nanopost in the center of the image sensor coincides with the position of the first nanopost,
The image sensor, in which the second nanopost is shifted toward the center of the image sensor with respect to the first nanopost in the peripheral part of the image sensor. The method of claim 18,
An image sensor, wherein a degree to which the second nanopost is shifted with respect to the first nanopost in a peripheral portion of the image sensor increases as the distance from the center of the image sensor increases. The method of claim 15,
Each of the plurality of nanoposts includes a first nanopost, a second nanopost stacked on the first nanopost, and a third nanopost stacked on the second nanopost,
The position of the second nanopost and the position of the third nanopost in the center of the image sensor coincide with the position of the first nanopost,
At the periphery of the image sensor, the second nanopost is shifted toward the center of the image sensor with respect to the first nanopost, and the third nanopost is toward the center of the image sensor with respect to the second nanopost. The image sensor, which is shifted towards the. The method of claim 15,
The line width of the nanoposts disposed in any one of the first, second, third, and fourth areas at the periphery of the image sensor is a nano-post disposed at the same location in the same area from the center of the image sensor. Image sensor, larger than the line width of the post. The method of claim 21,
When the line width of the nanopost at the periphery of the image sensor is w, and the line width of the nanopost at the center of the image sensor is w ₀ ,

Satisfies
Here, CRA is an incidence angle of light incident on the color separation lens array, an image sensor. The method of claim 21,
The image sensor, wherein the line width of the nanopost at the edge of the image sensor is 2.5% to 6.5% larger than the line width of the nanopost at the center of the image sensor. The method of claim 1,
The color separation lens array is disposed to protrude from the edge of the sensor substrate and further includes a plurality of first regions and a plurality of second regions that do not face any light sensing cells of the sensor substrate in a vertical direction. sensor. The method of claim 1,
The image sensor, wherein the total area of the color separation lens array is smaller than the total area of the sensor substrate. The method of claim 1,
The color separation lens array includes a first color separation lens array and a second color separation lens array disposed on the first color separation lens array,
The first and second microstructures of the first region and the second region of the first color separation lens array include a plurality of nanoposts, and the first region and the second region of the second color separation lens array The first microstructure and the second microstructure include a plurality of nanoposts, and the arrangement of the plurality of nanoposts of the first color separation lens array corresponds to the arrangement of the plurality of nanoposts of the second color separation lens array. Different, image sensor. A sensor substrate including a plurality of first light sensing cells and a plurality of second light sensing cells for sensing light: And
The plurality of first light sensing cells having a first dielectric having a first refractive index and forming a first pattern and a second dielectric having a second refractive index less than the first refractive index and filled between the first dielectrics of the first pattern A plurality of first regions respectively corresponding to, and a first dielectric having a first refractive index and forming a second pattern different from the first pattern, and a second dielectric having a second refractive index less than the first refractive index, and between the first dielectric of the second pattern Including; a color separation lens array having a second dielectric filled in and corresponding to each of the plurality of second light sensing cells,
In the first region and the second region, light of a first wavelength and light of a second wavelength different from among incident light incident on the color separation lens array are diverged in different directions, respectively, so that a first light sensing cell and a second light are formed. A phase distribution condensed by the sensing cell is formed at a position passing through the first region and the second region,
The image sensor, wherein the shape of the first pattern and the shape of the second pattern of the first area and the second area gradually change from the center of the color separation lens array toward the periphery of the color separation lens array. An imaging unit that focuses the light reflected from the subject to form an optical image; And
An electronic device comprising: the image sensor according to any one of claims 1 to 27, which converts the optical image formed by the imaging unit into an electrical signal. The method of claim 28,
The electronic device is a smart phone, a mobile phone, a personal digital assistant (PDA), a laptop, or a personal computer (PC).

Images