Image sensor with color separation lens array and electronic device including same

Abstract

To provide an image sensor including a color separation lens array, and an electronic device including the same.SOLUTION: In an image sensor including a color separation lens array 130, a pixel array 1100 includes: a sensor substrate 110 including a plurality of first photosensitive cells 111 and a plurality of second photosensitive cells 112 for sensing light; and the color separation lens array 130 including a plurality of first regions 131 corresponding to the respective first photosensitive cells and having a first microstructure, and a plurality of second regions 132 corresponding to the respective second photosensitive cells and having a second microstructure different from the first microstructure. The incident light that enters the color separation lens array is branched into light with a first wavelength and light with a second wavelength, which are different from each other, in different directions and the light is converged on the first photosensitive cells and the second photosensitive cells.SELECTED DRAWING: Figure 4A

Description

[Technical field]

[0001] The present invention relates to an image sensor having a color separation lens array and an electronic device including the image sensor, and more particularly to an image sensor having a color separation lens array capable of separating and focusing incident light according to wavelength, and an electronic device including the image sensor. [Background technology]

[0002] Image sensors generally use color filters to detect the color of incident light. However, color filters absorb the remaining colors of light except for the light of the color of interest, resulting in a decrease in light utilization efficiency. For example, when using an RGB color filter, only 1 / 3 of the incident light is transmitted and the remaining 2 / 3 is absorbed, resulting in a light utilization efficiency of only about 33%. Therefore, in the case of color display devices and color image sensors, most of the light loss occurs in the color filters. Summary of the Invention [Problem to be solved by the invention]

[0003] SUMMARY OF THE PRESENTLY PREFERRED EMBODIMENTS An object of the present invention is to provide an image sensor having improved light utilization efficiency by using a color separation lens array capable of separating and focusing incident light according to wavelength.

[0004] Another problem to be solved by the present invention is to provide an electronic device including the image sensor. [Means for solving the problem]

[0005] According to an embodiment, an image sensor includes: a sensor substrate including a plurality of first photosensitive cells and a plurality of second photosensitive cells for detecting light; and a color separation lens array including a plurality of first regions corresponding to the plurality of first photosensitive cells, each having a first microstructure, and a plurality of second regions corresponding to the plurality of second photosensitive cells, each having a second microstructure different from the first microstructure; wherein the first microstructure and the second microstructure are configured to separate light having a first wavelength and light having a second wavelength from each other in incident light incident on the color separation lens array in different directions. a phase distribution in which the light is branched in the color separation lens array toward the center of the color separation lens array and focused on the first photosensitive cells and the second photosensitive cells, respectively, is formed at a position where the light passes through the first region and the second region; at the central portion of the color separation lens array, the positions of the first region and the second region coincide with the positions of the first photosensitive cells and the second photosensitive cells corresponding thereto, respectively, and at the peripheral portion of the color separation lens array, the positions of the first region and the second region are also shifted toward the center of the color separation lens array with respect to the first photosensitive cells and the second photosensitive cells corresponding thereto.

[0006] In the peripheral portion of the color separation lens array, the degree to which the first and second regions are shifted relative to the corresponding first and second photosensitive cells becomes larger as the region moves away from the central portion of the color separation lens array.

[0007] The distance s by which the first regions and the second regions are shifted relative to the corresponding first and second photosensitive cells is given by:

[0008]

number

[0009] where 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 angle of incidence of light incident on the sensor substrate.

[0010] For example, the first microstructure and the second microstructure can cause the light of a first wavelength to form a phase distribution of 2Nπ at the center of the first photosensitive cell and a phase distribution of (2N-1)π at the center of the second photosensitive cell immediately after passing through the color separation lens array, where N is an integer greater than 0.

[0011] For example, the first microstructure and the second microstructure can cause the light of the second wavelength to form a phase distribution of (2M-1)π at the center of the first photosensitive cell and a phase distribution of 2Mπ at the center of the second photosensitive cell immediately after passing through the color separation lens array, where M is an integer greater than 0.

[0012] 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.

[0013] The theoretical thickness of the spacer layer is h t and the pitch of each of the first photosensitive cells and the second photosensitive cells is p, the thickness h of the spacer layer is h t -p≦h≦h t −p, and the theoretical thickness of the spacer layer is also the focal length of the color separation lens array at the center wavelength of the wavelength band of incident light that is color-separated by the color separation lens array.

[0014] The refractive index of the spacer layer is n, and the center wavelength of the wavelength band of light that is color-separated by the color separation lens array is λ 0 Then, the theoretical thickness of the spacer layer h t is expressed as follows:

[0015]

number

[0016] It is also expressed by:

[0017] The sensor substrate further includes a plurality of third photosensitive cells and a plurality of fourth photosensitive cells for detecting light, and the color separation lens array includes a plurality of third regions corresponding to the plurality of third photosensitive cells, respectively, and having a third microstructure different from the first microstructure and the second microstructure, and a plurality of fourth regions corresponding to the plurality of fourth photosensitive cells, respectively, and having a fourth microstructure different from the first microstructure to the third microstructure, and the first regions, the second regions, the third regions and the fourth regions are also respectively arranged along four quadrants.

[0018] At the central part of the image sensor, the positions of the first, second, third and fourth regions of the color separation lens array coincide with the positions of the first, second, third and fourth photosensitive cells corresponding thereto, respectively, and at the peripheral part of the image sensor, the first, second, third and fourth regions of the color separation lens array are also shifted toward the central part of the image sensor with respect to the first, second, third and fourth photosensitive cells corresponding thereto, respectively.

[0019] In the peripheral portion of the image sensor, the degree to which the first, second, third and fourth regions of the color separation lens array are shifted relative to the corresponding first, second, third and fourth photosensitive cells becomes larger as the region moves away from the central portion of the image sensor.

[0020] The first to fourth microstructures may split light of different first to third wavelengths, which are incident on the color separation lens array, into different directions, at positions passing through the first to fourth regions, to form a phase distribution in which the light of the first wavelength is focused on the first photosensitive cell and the fourth photosensitive cell, the light of the second wavelength is focused on the second photosensitive cell, and the light of the third wavelength is focused on the third photosensitive cell.

[0021] For example, the first wavelength is green light, the second wavelength is blue light, and the third wavelength is red light.

[0022] The first to fourth microstructures are configured so that, immediately after passing through the color separation lens array, the light having a first wavelength forms a phase distribution of 2Nπ at the central portion of the first photosensitive cell and the central portion of the fourth photosensitive cell and a phase distribution of (2N-1)π at the central portion of the second photosensitive cell and the central portion of the third photosensitive cell; and, immediately after passing through the color separation lens array, the light having a second wavelength forms a phase distribution of (2M-1)π at the central portion of the first photosensitive cell and the central portion of the fourth photosensitive cell and a phase distribution of (2M-1)π at the central portion of the second photosensitive cell. a phase distribution of 2Mπ at the center and a phase distribution greater than (2M-2)π and smaller than (2M-1)π at the center of the third photosensitive cell, and the light of the third wavelength can be made to form a phase distribution of (2L-1)π at the center of the first photosensitive cell and the center of the fourth photosensitive cell, a phase distribution of 2Lπ at the center of the third photosensitive cell, and a phase distribution greater than (2L-2)π and smaller than (2L-1)π at the center of the second photosensitive cell, immediately after passing through the color separation lens array.

[0023] The first to fourth microstructures in the first to fourth regions include a plurality of nanoposts, and the first to fourth regions may differ from each other in at least one of the shape, size, and arrangement of the nanoposts.

[0024] For example, the image sensor may have a pixel array structure in which a plurality of unit pixels including red, green, and blue pixels are repeatedly arranged, and the nanoposts provided in the first to fourth regions corresponding to the green pixels may have different distribution patterns along a first direction and a second direction perpendicular to the first direction.

[0025] In the first to fourth regions, the nanoposts provided in the regions corresponding to blue and red pixels may have a symmetrical distribution pattern along the first and second directions.

[0026] Each of the plurality of nanoposts includes a first nanopost and a second nanopost stacked on the first nanopost, and at a center of the image sensor, the positions of the second nanoposts coincide with the positions of the first nanoposts, and at a periphery of the image sensor, the second nanoposts are also shifted relative to the first nanoposts toward the center of the image sensor.

[0027] At the periphery of the image sensor, the degree to which the second nanoposts are shifted relative to the first nanoposts becomes greater the farther away from the center of the image sensor.

[0028] 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, and at the center of the image sensor, the positions of the second nanopost and the third nanopost coincide with the positions of the first nanopost, and at the periphery of the image sensor, the second nanopost is shifted toward the center of the image sensor relative to the first nanopost, and the third nanopost is also shifted toward the center of the image sensor relative to the second nanopost.

[0029] At the periphery of the image sensor, the line width of a nanopost arranged in one of the first region, the second region, the third region, and the fourth region is wider than the line width of a nanopost arranged at the same position in the same region at the center of the image sensor.

[0030] At the periphery of the image sensor, the nanoposts have a line width of w, and at the center of the image sensor, the nanoposts have a line width of w 0 When

[0031]

number

[0032] where CRA is the angle of incidence of light entering the color separation lens array.

[0033] At the outermost edges of the image sensor, the linewidth of the nanoposts may be 2.5% to 6.5% greater than the linewidth of the nanoposts at the center of the image sensor.

[0034] The color separation lens array may further include a plurality of first regions and a plurality of second regions that are arranged to protrude from an edge of the sensor substrate and do not face any of the photosensitive cells of the sensor substrate in the vertical direction.

[0035] The total area of ​​the color separation lens array is smaller than the total area of ​​the sensor substrate.

[0036] The color separation lens array includes a first color separation lens array and a second color separation lens array arranged on the first color separation lens array, the first microstructures and the second microstructures in the first and second regions of the first color separation lens array include a plurality of nanoposts, the first microstructures and the second microstructures in the first and second regions of the second color separation lens array include a plurality of nanoposts, and the arrangement shape of the plurality of nanoposts of the first color separation lens array is different from the arrangement shape of the plurality of nanoposts of the second color separation lens array.

[0037] According to another embodiment, an image sensor includes a sensor substrate including a plurality of first photosensitive cells and a plurality of second photosensitive cells for detecting light; a first dielectric having a first refractive index and forming a first pattern, and a second dielectric having a second refractive index smaller than the first refractive index and filled between the first dielectrics in the first pattern, a plurality of first regions respectively corresponding to the plurality of first photosensitive cells, 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 smaller than the first refractive index and filled between the first dielectrics in the second pattern, the first region and the second region form a phase distribution in which light having a first wavelength and light having a second wavelength that are different from each other are branched into different directions from each other among light incident on the color separation lens array and focused on the first photosensitive cells and the second photosensitive cells, respectively, at a position where the light passes through the first region and the second region, and a shape of a first pattern and a shape of a second pattern of the first region and the second region may gradually change from a center portion of the color separation lens array toward a periphery of the color separation lens array.

[0038] In yet another embodiment, the electronic device may include an imaging unit that focuses light reflected from a subject to form an optical image, and the aforementioned image sensor that converts the optical image formed by the imaging unit into an electrical signal.

[0039] 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). [Brief description of the drawings]

[0040] [Figure 1] FIG. 1 is a block diagram of an image sensor according to one embodiment. [Figure 2A] 1 is a diagram illustrating an example of a pixel arrangement of a pixel array of an image sensor. [Figure 2B]10 is a diagram illustrating an example of another pixel arrangement of a pixel array of an image sensor; [Figure 2C] 13 is a diagram illustrating an example of yet another pixel arrangement of a pixel array of an image sensor; [Diagram 3] 1 is a conceptual diagram illustrating the general structure and operation of a color separation lens array according to one embodiment. [Figure 4A] 1 is a schematic cross-sectional view showing one cross section of a pixel array of an image sensor according to an embodiment. [Figure 4B] 4 is a schematic cross-sectional view showing another cross section of a pixel array of an image sensor according to an embodiment. FIG. [Figure 5A] FIG. 2 is a plan view illustrating an arrangement of photosensitive cells in a pixel array of an image sensor. [Figure 5B] 1 is a plan view illustrating an example of a pixel array of an image sensor in which a plurality of nanoposts are arranged in a plurality of regions of a color separation lens array. [Figure 5C] FIG. 5C is an enlarged plan view showing a portion of FIG. 5B in detail. [Figure 6A] 13 is a diagram showing a phase distribution of blue light that has passed through a color separation lens array. [Figure 6B] 13 is a diagram showing a computer-simulated blue light focusing distribution in opposing photosensitive cells; [Figure 6C] 11 is a diagram illustrating an example of a traveling direction of blue light incident on a second region of a color separation lens array corresponding to a blue pixel and its periphery; [Figure 6D] 1 is a diagram illustrating an example of a microlens array that functions equivalently to a color separation lens array for blue light. [Figure 7A] 13 is a diagram showing a phase distribution of green light that has passed through a color separation lens array. [Figure 7B] 13 is a diagram showing a computer-simulated green light focusing distribution in opposing photosensitive cells; [Figure 7C] 11 is a diagram showing an example of a traveling direction of green light incident on a first region of a color separation lens array corresponding to a green pixel and its periphery; [Figure 7D] 13 is a diagram illustrating an example of a microlens array that functions equivalently to a color separation lens array for green light. [Figure 8A] 13 is a diagram showing a phase distribution of red light that has passed through a color separation lens array. [Figure 8B] 13 is a diagram showing a computer-simulated red light focusing distribution in opposing photosensitive cells; [Figure 8C] 13 is a diagram illustrating an example of a traveling direction of red light incident on a third region of a color separation lens array corresponding to a red pixel and its periphery; [Figure 8D] 13 is a diagram illustrating an example of a microlens array that functions equivalently to a color separation lens array for red light. [Figure 9A] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 0.7 μm; [Figure 9B] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 0.7 μm; [Figure 9C] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 0.7 μm; [Figure 9D] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 0.7 μm; [Figure 9E] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 0.7 μm; [Figure 10A] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 0.8 μm; [Figure 10B]13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 0.8 μm; [Figure 10C] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 0.8 μm; [Figure 10D] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 0.8 μm; [Figure 10E] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 0.8 μm; [Figure 11A] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 1.0 μm. [Figure 11B] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 1.0 μm. [Figure 11C] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 1.0 μm. [Figure 11D] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 1.0 μm. [Figure 11E] 13 is a graph showing an example of how the efficiency of a color separation lens array changes depending on the distance between the color separation lens array and a sensor substrate when the pitch of photosensitive cells is 1.0 μm. [Figure 12] 1 is a perspective view illustrating an exemplary configuration of nanoposts that may be employed in a color separation lens array of an image sensor according to an embodiment. [Figure 13A]11A and 11B are plan views illustrating example shapes of nanoposts that may be employed in a color separation lens array of an image sensor according to another embodiment. [Figure 13B] 11A and 11B are plan views illustrating example shapes of nanoposts that may be employed in a color separation lens array of an image sensor according to another embodiment. [Figure 13C] 11A and 11B are plan views illustrating example shapes of nanoposts that may be employed in a color separation lens array of an image sensor according to another embodiment. [Figure 13D] 11A and 11B are plan views illustrating example shapes of nanoposts that may be employed in a color separation lens array of an image sensor according to another embodiment. [Figure 13E] 11A and 11B are plan views illustrating example shapes of nanoposts that may be employed in a color separation lens array of an image sensor according to another embodiment. [Figure 13F] 11A and 11B are plan views illustrating example shapes of nanoposts that may be employed in a color separation lens array of an image sensor according to another embodiment. [Figure 13G] 11A and 11B are plan views illustrating example shapes of nanoposts that may be employed in a color separation lens array of an image sensor according to another embodiment. [Figure 13H] 11A and 11B are plan views illustrating example shapes of nanoposts that may be employed in a color separation lens array of an image sensor according to another embodiment. [Figure 14] 13 is a plan view illustrating an example of an arrangement of a plurality of nanoposts constituting a color separation lens array of an image sensor according to another embodiment. [Figure 15] 13 is a plan view illustrating an exemplary arrangement of a plurality of nanoposts constituting a color separation lens array of an image sensor according to yet another embodiment. [Figure 16] 13 is a plan view illustrating an exemplary arrangement of a plurality of nanoposts constituting a color separation lens array of an image sensor according to yet another embodiment. [Figure 17] 13 is a plan view illustrating an exemplary arrangement of a plurality of nanoposts constituting a color separation lens array of an image sensor according to yet another embodiment. [Figure 18]18 is a graph showing an example of the spectral distribution of light incident on red, green, and blue pixels of an image sensor having the color separation lens array of FIG. 17; [Figure 19A] FIG. 11 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor according to another embodiment. [Figure 19B] 11 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor according to another embodiment of the present invention in another cross section. [Figure 20] 4 is a graph showing an example of a spectral distribution of light incident on red, green, and blue pixels of an image sensor according to an embodiment, in which a color filter is provided; [Figure 21] 4 is a graph showing an example of a spectral distribution of light incident on red, green, and blue pixels of an image sensor according to an embodiment, in a case where no color filter is provided; [Figure 22] FIG. 1 is a conceptual diagram illustrating a camera according to an embodiment. [Figure 23A] 1 is a plan view showing changes in the arrangement of nanoposts of a color separation lens array depending on the position on an image sensor. FIG. [Figure 23B] 1 is a plan view showing changes in the arrangement of nanoposts of a color separation lens array depending on the position on an image sensor. FIG. [Figure 23C] 1 is a plan view showing changes in the arrangement of nanoposts of a color separation lens array depending on the position on an image sensor. FIG. [Figure 24] 11 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor according to another embodiment. [Diagram 25] 23 is a plan view illustratively showing the shifting shape of two-dimensionally arranged nanoposts in a color separation lens array applied to the image sensor of the camera shown in FIG. 22. [Figure 26] 26 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor having a color separation lens array shown in FIG. 25. [Figure 27]27A and 27B are perspective views illustrating example shapes of nanoposts employed in the color separation lens array of the image sensor of FIG. 26. [Figure 28] 11 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor according to another embodiment. [Figure 29A] 1 is a graph showing an example of a spectral distribution of light incident on red, green, and blue pixels of an image sensor according to an embodiment, in which a change in a chief ray angle depending on a position on the image sensor is not taken into consideration. [Figure 29B] 1 is a graph showing an example of the spectral distribution of light incident on red, green, and blue pixels of an image sensor according to an embodiment, in which the position of the nanopost is changed while taking into account the change in the chief ray angle. [Figure 29C] 1 is a graph showing an example of the spectral distribution of light incident on red, green, and blue pixels of an image sensor according to an embodiment, in which nanoposts are arranged in two stages in consideration of changes in the chief ray angle. [Figure 30A] 13 is a plan view showing a change in line width of a nanopost depending on a position on an image sensor according to another embodiment. FIG. [Figure 30B] 13 is a plan view showing a change in line width of a nanopost depending on a position on an image sensor according to another embodiment. FIG. [Diagram 31] 31 is a graph showing an example of the spectral distribution of light incident on red, green, and blue pixels of the image sensor shown in FIG. 30; [Diagram 32] 13 is a plan view showing one shape of nanoposts employed in a color separation lens array according to another embodiment. FIG. [Diagram 33] 13A and 13B are plan views showing other shapes of nanoposts employed in a color separation lens array according to another embodiment. [Diagram 34] 11 is a cross-sectional view showing one cross-sectional shape of a nanopost employed in a color separation lens array according to another embodiment. FIG. [Diagram 35]11A and 11B are cross-sectional views showing other cross-sectional shapes of nanoposts employed in a color separation lens array according to another embodiment. [Diagram 36] 11 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor according to another embodiment. [Figure 37] 11A and 11B are conceptual diagrams illustrating the general structure and operation of a color separation lens array according to another embodiment. [Figure 38] 1 is a plan view illustrating an example of a unit pattern array of a color separation lens array that is also applied to a Bayer pattern type image sensor; [Figure 39] 39 is a cross-sectional view illustratively showing a vertical cross section of the unit pattern array shown in FIG. 38 taken along line AA'. [Diagram 40] 39 is a cross-sectional view illustratively showing a vertical cross section of the unit pattern array shown in FIG. 38 taken along line BB'. [Diagram 41] 10 is a plan view showing an example of an arrangement of a color separation lens array including a plurality of the illustrated unit pattern arrays. FIG. [Figure 42A] 39 is a diagram illustrating an example of a first region in the unit pattern array illustrated in FIG. 38. [Figure 42B] 2 is a diagram illustrating an example of a pixel and its neighboring pixels of an image sensor corresponding to the pixel; [Figure 43A] 39 is a diagram illustrating an example of a second region in the unit pattern array illustrated in FIG. 38. [Figure 43B] 2 is a diagram illustrating an example of a pixel and its neighboring pixels of an image sensor corresponding to the pixel; [Figure 44A] 39 is a diagram illustrating an example of a third region in the unit pattern array illustrated in FIG. 38. [Figure 44B] 2 is a diagram illustrating an example of a pixel and its neighboring pixels of an image sensor corresponding to the pixel; [Figure 45A] 39 is a diagram illustrating an example of a fourth region in the unit pattern array illustrated in FIG. 38. [Figure 45B]2 is a diagram illustrating an example of a pixel and its neighboring pixels of an image sensor corresponding to the pixel; [Figure 46] 13 is a plan view illustrating an example of a shape of a unit pattern array of a color separation lens array according to another embodiment. FIG. [Figure 47] 13 is a plan view illustrating an example of a shape of a unit pattern array of a color separation lens array according to another embodiment. FIG. [Figure 48A] 1 is a schematic cross-sectional view showing one cross section of a pixel array of an image sensor that employs a color separation lens array. [Figure 48B] 1 is a schematic cross-sectional view showing another cross section of a pixel array of an image sensor employing a color separation lens array. [Figure 49] 11 is a plan view illustrating an example of a color separation lens array according to another embodiment. [Figure 50] 50 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor including the color separation lens array shown in FIG. 49. [Figure 51] 13 is a plan view illustrating an example of an arrangement of a plurality of unit pattern arrays of a color separation lens array according to another embodiment. FIG. [Figure 52] 11 is a cross-sectional view showing a schematic structure of a pixel array of an image sensor according to another embodiment. [Figure 53] 1 is a block diagram that illustrates a schematic diagram of an electronic device including an image sensor according to an embodiment. [Figure 54] 1 is a diagram illustrating an example of an electronic device to which an image sensor according to an embodiment is applied. [Figure 55] 1 is a diagram illustrating another example of an electronic device to which an image sensor according to an embodiment is applied. [Figure 56] 1 is a diagram illustrating yet another example of an electronic device to which an image sensor according to an embodiment is applied. [Figure 57] 1 is a diagram illustrating yet another example of an electronic device to which an image sensor according to an embodiment is applied. [Figure 58] 1 is a diagram illustrating yet another example of an electronic device to which an image sensor according to an embodiment is applied. [Figure 59] 1 is a diagram illustrating yet another example of an electronic device to which an image sensor according to an embodiment is applied. [Figure 60] 1 is a diagram illustrating yet another example of an electronic device to which an image sensor according to an embodiment is applied. [Figure 61] 1 is a diagram illustrating yet another example of an electronic device to which an image sensor according to an embodiment is applied. [Figure 62] 1 is a diagram illustrating yet another example of an electronic device to which an image sensor according to an embodiment is applied. [Figure 63] 1 is a diagram illustrating yet another example of an electronic device to which an image sensor according to an embodiment is applied. [Figure 64] 1 is a diagram illustrating yet another example of an electronic device to which an image sensor according to an embodiment is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Hereinafter, an image sensor having 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 such embodiments. In the following drawings, the same reference numerals refer to the same components, and the size of each component may be exaggerated in the drawings for clarity and convenience of description.

[0042] In the following description, the expression "upper" or "above" may include not only things that are in contact and immediately above, below, left or right of one another, but also things that are not in contact and are immediately above, below, left or right of one another.

[0043] Terms such as first and second are used in the description of various components only to distinguish one component from another, and are not intended to limit the materials or structures of the components.

[0044] The singular expression includes the plural expression unless the context clearly indicates otherwise. Furthermore, when a part "includes" a certain element, it does not mean excluding other elements, but means that other elements may be further included, unless otherwise specified to the contrary.

[0045] In addition, terms such as "unit" and "module" used in the specification refer to a unit that processes a function or operation, and may be realized by hardware or software, or a combination of hardware and software.

[0046] Use of the terms "said" and similar referents refers to both the singular and the plural.

[0047] The steps constituting the method may be performed in any suitable order unless expressly stated to be performed in the order described. In addition, the use of all exemplary terms (such as "for example") is merely for the purpose of explaining the technical idea in detail, and such terms are not intended to limit the scope of the claims, except as otherwise limited by the claims.

[0048] 1 is a schematic block diagram of an image sensor according to an embodiment. Referring to FIG. 1, an image sensor 1000 may include a pixel array 1100, a timing controller (T / C) 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.

[0049] The pixel array 1100 includes pixels two-dimensionally arranged along a plurality of rows and columns. The row decoder 1020 selects one row of the pixel array 1100 in response to a row address signal output from the timing controller 1010. The output circuit 1030 outputs a photodetection signal in units of columns 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 analog to digital converters arranged for each column between the column decoder and the pixel array 1100, or one analog to digital converter arranged at an output end of the column decoder. The timing controller 1010, the row decoder 1020, and the output circuit 1030 may be implemented on a single chip or on separate chips. A processor for processing the video signal output via the output circuit 1030 is also embodied on one chip together with the timing controller 1010, the row decoder 1020, and the output circuit 1030.

[0050] The pixel array 1100 may include a number of pixels that are sensitive to light of different wavelengths, and the pixels may be arranged in a variety of ways, such as those shown in Figures 2A to 2C.

[0051] First, FIG. 2A shows a Bayer pattern that is 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 blue pixels B, green pixels G, red pixels R, and green pixels G, respectively. Such unit pixels are two-dimensionally arranged in a repeated manner along a first direction (X direction) and a second direction (Y direction). In other words, in a unit pixel having a 2×2 array, two green pixels G are arranged in one diagonal direction, and one blue pixel B and one red pixel R are arranged in the other diagonal direction. In terms of 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 the first direction, and a second row in which a plurality of red pixels R and a plurality of green pixels G are alternately arranged along the first direction are repeatedly arranged.

[0052] However, the arrangement of the pixel array 1100 is not limited to the Bayer pattern, and various arrangements are possible other than the Bayer pattern. For example, referring to FIG. 2B, a CYGM arrangement in which a magenta pixel M, a cyan pixel C, a yellow pixel Y, and a green pixel G constitute one unit pixel is also possible. 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. 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 depending on the color characteristics of the image sensor 1000. In the following, for convenience, the pixel array 1100 of the image sensor 1000 is described as having a Bayer pattern, but the principles of the embodiments described below may be applied to pixel arrangements of other forms other than the Bayer pattern.

[0053] According to an embodiment, the pixel array 1100 of the image sensor 1000 may include a color separation lens array configured to focus light of a color corresponding to each pixel. FIG. 3 is a conceptual diagram showing a schematic structure and operation of a color separation lens array according to an embodiment. Referring to FIG. 3, the color separation lens array 130 includes nanopost NPs arranged on the same plane according to a predetermined rule. Such a color separation lens array 130 is also arranged on the spacer layer 120.

[0054] Here, the rule applies to parameters such as the shape, size (width, height), spacing, and array form of the nanopost NPs, and the incident light L i The target phase distribution TP is also determined by the target phase distribution TP realized by the color separation lens array 130 with respect to the incident light L i The target phase distribution TP is also determined by considering the target areas R1 and R2 that separate and collect the wavelengths of the incident light L. The target phase distribution TP is shown between the color separation lens array 130 and the target areas R1 and R2, but this is merely for convenience of illustration. The actual target phase distribution TP is i means the phase distribution at a position immediately after passing through the color separation lens array 130, for example, at the lower surface of the color separation lens array 130 or the upper surface of the spacer layer 120.

[0055] The color separation lens array 130 may include a first region 131 and a second region 132 each having a first microstructure and a second microstructure different from each other. For example, the first region 131 and the second region 132 may each include one or more nanopost NPs. The first region 131 and the second region 132 may be arranged to face the first target region R1 and the second target region R2, respectively, and may correspond one-to-one. Although the first region 131 and the second region 132 are illustrated as having three nanopost NPs arranged therein, this is merely an example. In addition, the nanopost NPs are illustrated as being entirely located within a certain region of the first region 131 and the second region 132, but this is not limited thereto, and some nanopost NPs may also be arranged at the boundary between the first region 131 and the second region 132.

[0056] The nanoposts NP of the color separation lens array 130 are incident light L i It is possible to form a phase distribution in which the light of different wavelengths contained in the incident light L is split into different directions and focused. i The light of the first wavelength contained in λ1 has a first phase distribution and a second wavelength of light L λ2 The shape, size, arrangement, etc. of the nanoposts NP distributed in the first region 131 and the second region 132 can be determined so as to form a target phase distribution TP having a second phase distribution. With such a target phase distribution TP, the array of nanoposts NP and the light L of the first wavelength are respectively directed to target positions R1 and R2 at a predetermined separation distance A. λ1 and the second wavelength light L λ2 and can be collected.

[0057] The arrangement of the nanoposts NPs in the first region 131 may be different from the arrangement of the nanoposts NPs in the second region 132. In other words, any one of the shape, size, and arrangement of the nanoposts NPs in the first region 131 may be different from the shape, size, and arrangement of the nanoposts NPs in the second region 132.

[0058] The nanopost NP may have a shape dimension of a sub-wavelength smaller than the wavelength band to be split. The nanopost NP may have a shape dimension smaller than the shorter wavelength of the first wavelength and the second wavelength, and the incident light L i When is visible light, it can have dimensions smaller than 400 nm, 300 nm or 200 nm.

[0059] Nanopost NPs can also be made of materials that have a higher refractive index than the surrounding materials. For example, nanopost NPs can be made of c-Si (crystalline silicon), p-Si (polysilicon), a-Si (amorphous silicon), III-V compound semiconductors (GaP, GaN, GaAs, etc.), SiC, TiO 2 , SiN, and / or a combination thereof. Nanopost NPs, which have a refractive index difference with the surrounding material, can change the phase of light passing through them. This is due to a phase delay caused by the sub-wavelength shape and dimensions, and the degree of phase delay is determined by the detailed shape, dimensions, arrangement form, etc. of the nanopost NPs. The surrounding material is a dielectric material with a refractive index lower than that of the nanopost NPs, such as SiO 2 Or it can be air.

[0060] The first wavelength λ1 and the second wavelength λ2 may be visible light wavelength bands, but are not limited thereto, and various wavelength bands may be realized depending on the order of the arranged nanoposts NPs. Although Fig. 3 illustrates an example in which two wavelengths are split and focused, the present invention is not limited thereto, and incident light may be split and focused in three or more directions depending on the wavelength.

[0061] In the following, an example in which the above-mentioned color separation lens array 130 is applied to the pixel array 1100 of the image sensor 1000 will be described in more detail.

[0062] 4A and 4B are cross-sectional views of a pixel array according to one embodiment, FIG. 5A is a plan view illustrating a schematic arrangement of photosensitive cells in the pixel array, and FIG. 5B is a plan view illustrating an example of an arrangement of nanoposts in a color separation lens array.

[0063] 4A and 4B, the pixel array 1100 includes a sensor substrate 110 including a plurality of photosensitive cells 111, 112, 113, and 114 for sensing light, a transparent spacer layer 120 disposed on the sensor substrate 110, and a color separation lens array 130 disposed on the spacer layer 120.

[0064] The sensor substrate 110 may include a first photosensitive cell 111, a second photosensitive cell 112, a third photosensitive cell 113, and a fourth photosensitive cell 114 that convert light into an electrical signal. As shown in Fig. 4A, the first photosensitive cells 111 and the second photosensitive cells 112 are alternately arranged along a first direction (X direction), and in a cross section at a different position in the Y direction, as shown in Fig. 4B, the third photosensitive cells 113 and the fourth photosensitive cells 114 are alternately arranged. Such region division is for dividing incident light into pixel units for sensing. For example, the first photosensitive cell 111 and the fourth photosensitive cell 114 may sense light of a first wavelength corresponding to a first pixel, the second photosensitive cell 112 may sense light of a second wavelength corresponding to a second pixel, and the third photosensitive cell 113 may sense light of a third wavelength corresponding to a third pixel. In the following description, the first wavelength light is green light, the second wavelength light is blue light, and the third wavelength light is red light, and the first pixel, the second pixel, and the third pixel are a green pixel G, a blue pixel B, and a red pixel R, respectively. Although not shown, a separation film for separating cells may be further formed at the boundaries between the cells.

[0065] The spacer layer 120 supports the color separation lens array 130 and maintains a constant distance between the sensor substrate 110 and the color separation lens array 130. The spacer layer 120 is made of a material transparent to visible light. For example, the spacer layer 120 is made of SiO 2Alternatively, the color separation lens array 130 may be made of a dielectric material, such as siloxane-based spin on glass (SOG), that has a refractive index lower than that of the nanopost NPs of the color separation lens array 130 and has low absorption in the visible light range.

[0066] The color separation lens array 130 includes nanoposts NPs arranged according to a predetermined rule. Although not shown, the color separation lens array 130 may further include a protective layer for protecting the nanoposts NPs. The protective layer may be made of a dielectric material having a refractive index lower than that of the material forming the nanoposts NPs.

[0067] The color separation lens array 130 is divided into a number of regions 131, 132, 133, and 134 that face the photosensitive cells 111, 112, 113, and 114 in a one-to-one correspondence with each other. One or a number of nanoposts NPs are arranged in each of the multiple regions 131, 132, 133, and 134, and any one of the shape, size, and arrangement may differ depending on the region.

[0068] The color separation lens array 130 is divided into regions so that light having a first wavelength is branched and focused to the first photosensitive cell 111 and the fourth photosensitive cell 114, light having a second wavelength is branched and focused to the second photosensitive cell 112, and light having a third wavelength is branched and focused to the third photosensitive cell 113, and the size, shape and arrangement of the nanoposts NPs are determined for each region.

[0069] If the pixel array 1100 has a Bayer pattern arrangement as shown in FIG. 2A , the first photosensitive cell 111 and the fourth photosensitive cell 114 in FIG. 5A correspond to a green pixel G, the second photosensitive cell 112 corresponds to a blue pixel B, and the third photosensitive cell 113 corresponds to a red pixel R.

[0070] 5B, the first region 131 and the fourth region 134 of the color separation lens array 130 correspond to a green pixel G, the second photosensitive cell 112 and the second region 132 correspond to a blue pixel B, and the third photosensitive cell 113 and the third region 133 correspond to a red pixel R. Thus, the color separation lens array 130 includes a plurality of unit pattern arrays arranged two-dimensionally, and each unit pattern array includes the first region 131, the second region 132, the third region 133, and the fourth region 134 arranged in a 2×2 pattern.

[0071] 5B, the first region 131 and fourth region 134 corresponding to the green pixel G, the second region 132 corresponding to the blue pixel B, and the third region 133 corresponding to the red pixel R may include cylindrical nanopost NPs having a circular cross section. Nanopost NPs having different cross-sectional areas may be arranged in the centers of the first region 131, the second region 132, the third region 133, and the fourth region 134, and nanopost NPs may also be arranged at the centers of the inter-pixel boundary lines and at intersections of the pixel boundary lines. The cross-sectional area of ​​the nanopost NPs arranged at the inter-pixel boundary lines may be smaller than that of the nanopost NPs arranged at the center of the pixels.

[0072] FIG. 5C shows in detail a portion of FIG. 5B, i.e., the nanopost NP arrangement in the first region 131 to the fourth region 134 constituting the unit pattern array. In FIG. 5C, the nanopost NPs are indicated as p1 to p9 according to their detailed positions in the unit pattern array. Referring to FIG. 5C, among the nanoposts NPs, the nanopost p1 arranged at the center of the first region 131 and the nanopost p4 arranged at the center of the fourth region 134 have a larger cross-sectional area than the nanopost p2 arranged at the center of the second region 132 and the nanopost p3 arranged at the center of the third region 133, and the cross-sectional area of ​​the nanopost p2 arranged at the center of the second region 132 is larger than the cross-sectional area of ​​the nanopost p3 arranged at the center of the third region 133. However, this is merely one example, and nanopost NPs of various shapes, sizes, and arrangements may be applied as necessary.

[0073] The nanoposts NP provided in the first region 131 and the fourth region 134 corresponding to the green pixel G may have different distribution patterns along the first direction (X direction) and the second direction (Y direction). For example, the nanoposts NP arranged in the first region 131 and the fourth region 134 may have different size arrangements along the first direction (X direction) and the second direction (Y direction). As shown in FIG. 5C, among the nanoposts NP, the cross-sectional area of ​​the nanopost p5 located at the boundary between the first region 131 and the second region 132 adjacent thereto in the first direction (X direction) is different from the cross-sectional area of ​​the nanopost p6 located at the boundary between the first region 131 and the third region 133 adjacent thereto in the second direction (Y direction). Similarly, the cross-sectional area of ​​nanopost p7 located at the boundary between the fourth region 134 and the third region 133 adjacent to it in the first direction (X direction) is different from the cross-sectional area of ​​nanopost p8 located at the boundary between the fourth region 134 and the second region 132 adjacent to it in the second direction (Y direction).

[0074] Meanwhile, the nanoposts NP arranged in the second region 132 corresponding to the blue pixel B and the third region 133 corresponding to the red pixel R may have a symmetrical distribution pattern along the first direction (X direction) and the second direction (Y direction). As shown in Fig. 5C, among the nanoposts NP, in the second region 132, the cross-sectional areas of the nanopost p5 arranged at the boundary between adjacent pixels in the first direction (X direction) and the nanopost p8 arranged at the boundary between adjacent pixels in the second direction (Y direction) are the same, and also in the third region 133, the cross-sectional areas of the nanopost p7 arranged at the boundary between adjacent pixels in the first direction (X direction) and the nanopost p6 arranged at the boundary between adjacent pixels in the second direction (Y direction) are the same.

[0075] On the other hand, the nanoposts p9 arranged at the corners of the first region 131, the second region 132, the third region 133, and the fourth region 134, i.e., at the intersections of the four regions, have the same cross-sectional area. Such a distribution is due to the pixel arrangement of the Bayer pattern. The blue pixel B and the red pixel R are the same as the green pixel G in the first direction (X direction) and the second direction (Y direction), while the green pixel G corresponding to the first region 131 is different from the pixel G in that the pixel adjacent to it in the first direction (X direction) is the blue pixel B and the pixel adjacent to it in the second direction (Y direction), and the green pixel G corresponding to the fourth region 134 is different from the pixel G in that the pixel adjacent to it in the first direction (X direction) is the red pixel R and the pixel adjacent to it in the second direction (Y direction). In addition, the green pixels G corresponding to the first region 131 and the fourth region 134 have four diagonally adjacent pixels that are the same as the green pixels G, the blue pixels B corresponding to the second region 132 have four diagonally adjacent pixels that are the same as the red pixels R, and the red pixels R corresponding to the third region 133 have four diagonally adjacent pixels that are the same as the blue pixels B. Therefore, in the second region 132 and the third region 133 corresponding to the blue pixels B and the red pixels R, respectively, the nanoposts NP may be arranged in a four-fold symmetry form, and in the first region 131 and the fourth region 134 corresponding to the green pixels G, the nanoposts NP may be arranged in a two-fold symmetry form. In particular, the first region 131 and the fourth region 134 are rotated by 90° with respect to each other.

[0076] Although the nanoposts NP are illustrated as having a symmetrical circular cross-sectional shape, the present invention is not limited thereto, and some nanoposts may have an asymmetrical cross-sectional shape. For example, the first region 131 and the fourth region 134 corresponding to the green pixel G may employ nanoposts having an asymmetrical cross-sectional shape with different widths in the first direction (X direction) and the second direction (Y direction), and the second region 132 and the third region 133 corresponding to the blue pixel B and the red pixel R may employ nanoposts having a symmetrical cross-sectional shape with the same widths in the first direction (X direction) and the second direction (Y direction).

[0077] The illustrated arrangement pattern of the color separation lens array 130 is merely one example for realizing a target phase distribution in which light having a first wavelength is branched and focused at the first photosensitive cell 111 and the fourth photosensitive cell 114, light having a second wavelength is branched and focused at the second photosensitive cell 112, and light having a third wavelength is branched and focused at the third photosensitive cell 113, and is not limited to the pattern illustrated in the figure.

[0078] The shape, size and arrangement of the nanoposts NP provided in each region of the color separation lens array 130 can be determined so that, at a position where the light of the first wavelength has passed through the color separation lens array 130, the light forms a phase where it is focused on the first photosensitive cell 111 and the fourth photosensitive cell 114 and does not travel to the second photosensitive cell 112 or the third photosensitive cell 113.

[0079] Similarly, the shape, size and arrangement of the nanoposts NP provided in each region of the color separation lens array 130 can be determined so that, at a position where the light of the second wavelength has passed through the color separation lens array 130, the light forms a phase where the light is focused on the second photosensitive cell 112 and does not proceed to the first photosensitive cell 111, the third photosensitive cell 113, or the fourth photosensitive cell 114.

[0080] Similarly, the shape, size and arrangement of the nanoposts NP provided in each region of the color separation lens array 130 can be determined so that, at a position where the light of the third wavelength has passed through the color separation lens array 130, the light forms a phase where the light is focused on the third photosensitive cell 113 and does not proceed to the first photosensitive cell 111, the second photosensitive cell 112, or the fourth photosensitive cell 114.

[0081] The shape, size and / or arrangement of the nanoposts NPs that satisfy all of these conditions can be determined, and such a color separation lens array 130 can be configured so that light immediately after passing through it has a target phase distribution as follows: Just after passing through the color separation lens array 130, in other words, 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 2Nπ at the center of the first region 131 corresponding to the first photosensitive cell 111 and the center of the fourth region 134 corresponding to the fourth photosensitive cell 114, and also has a distribution showing a phase of (2N-1)π at the center of the second region 132 corresponding to the second photosensitive cell 112 and the center of the third region 133 corresponding to the third photosensitive cell 113. Here, N is an integer greater than 0. In other words, the phase of the light of the first wavelength is maximum at the center of the first region 131 and the center of the fourth region 134 at a position immediately after passing through the color separation lens array 130, and gradually becomes smaller in a concentric manner as it gets farther from the center of the first region 131 and the center of the fourth region 134, and is also minimum at the center of the second region 132 and the center of the third region 133. For example, when N=1, the phase of the green light is 2π at the center of the first region 131 and the center of the fourth region 134 at a position after passing through the color separation lens array 130, and is also π at the center of the second region 132 and the center of the third region 133. Here, the phase means a relative phase value with respect to the phase immediately before the light passes through the nanopost NP.

[0082] Furthermore, just after passing through the color separation lens array 130, the phase of the light with the second wavelength is 2Mπ at the center of the second region 132 corresponding to the second photosensitive cell 112, is (2M-1)π at the center of the first region 131 corresponding to the first photosensitive cell 111 and at the center of the fourth region 134 corresponding to the fourth photosensitive cell 114, and is greater than (2M-2)π and smaller than (2M-1)π at the center of the third region 133 corresponding to the third photosensitive cell 113. Here, M is an integer greater than 0. In other words, just after passing through the color separation lens array 130, the phase of the light with the second wavelength is maximum at the center of the second region 132, concentrically decreases gradually with increasing distance from the center of the second region 132, and is locally minimum at the center of the third region 133. For example, when M=1, at the position where it passes through the color separation lens array 130, the phase of the light of the second wavelength is 2π at the center of the second region 132, π at the center of the first region 131 and the center of the fourth region 134, and approximately 0.2π to 0.7π at the center of the third region 133.

[0083] Similarly, just after passing through the color separation lens array 130, the phase of the light with the third wavelength is 2Lπ at the center of the third region 133 corresponding to the third photosensitive cell 113, is (2L-1)π at the centers of the first region 131 corresponding to the first photosensitive cell 111 and the fourth region 134 corresponding to the fourth photosensitive cell 114, and is greater than (2L-2)π and smaller than (2L-1)π at the center of the second region 132 corresponding to the second photosensitive cell 112. Here, L is an integer greater than 0. In other words, just after passing through the color separation lens array 130, the phase of the light with the third wavelength is maximum at the center of the third region 133, concentrically decreases gradually with increasing distance from the center of the third region 133, and is locally minimum at the center of the second region 132. For example, when L=1, at the position where it passes through the color separation lens array 130, the phase of the third wavelength light is 2π at the center of the third region 133, π at the center of the first region 131 and the center of the fourth region 134, and approximately 0.2π to 0.7π at the center of the second region 132.

[0084] As described above, the target phase distribution refers to the phase distribution of light at a position immediately after it has passed through the color separation lens array 130. If the light that has passed through the color separation lens array 130 has such a phase distribution, the light of the first to third wavelengths will be concentrated in the first to fourth photosensitive cells 111 to 114, respectively. In other words, the light that has passed through the color separation lens array 130 can be advantageously branched according to its wavelength, and each of the light beams travels in a different direction and is then concentrated.

[0085] In this way, a certain propagation distance requirement is determined so that light of that wavelength can be focused on that photosensitive cell, and the thickness h of the spacer layer 120 can be determined accordingly. The thickness h of the spacer layer 120 also varies depending on the wavelength λ to be split, the pixel size, and the arrangement period p of the photosensitive cells. The thickness h of the spacer layer 120 is larger than the central wavelength λ of the visible light wavelength band to be split, and is in the range of 1p to 3p compared with the arrangement period p of the photosensitive cells, which is the distance between the centers of adjacent photosensitive cells. To be more specific, the thickness h of the spacer layer 120 is in the range of 500 nm to 5 μm. Details of setting the thickness h of the spacer layer 120 will be described later with reference to FIGS. 9A to 9E, 10A to 10E, and 11A to 11E.

[0086] 6A and 6B are computer-generated images of the phase distribution of blue light passing through a color separation lens array and the focusing distribution of blue light in the facing photosensitive cells. FIG. 6C exemplarily illustrates the traveling direction of blue light incident on a second region of the color separation lens array corresponding to blue pixel B and its periphery. FIG. 6D exemplarily illustrates a microlens array that acts equivalently to the color separation lens array with respect to blue light.

[0087] Regarding the phase distribution illustrated in Figure 6A, the phase at the center of the area corresponding to the blue pixel B is approximately 2π, the phase at the center of the area corresponding to the adjacent green pixel G exhibits approximately a π value, and the phase at the center of the area corresponding to the diagonal red pixel R exhibits approximately a value smaller than π (e.g., approximately 0.2π to 0.7π).

[0088] Such a phase distribution may show a focusing distribution of blue light as shown in Fig. 6B, in which the blue light is mostly focused in an area corresponding to the blue pixel B, and almost no blue light reaches areas corresponding to other pixels.

[0089] As a result, the blue light incident on the second region 132 corresponding to the blue pixel B and its periphery travels as shown in Fig. 6C after passing through the color separation lens array 130. For example, the blue light among the incident light incident on the second region 132 of the color separation lens array 130 and parts of other regions surrounding the second region 132 is focused on the second photosensitive cell 112 immediately below the second region 132. In other words, blue light from the second region 132 corresponding to the blue pixel B, blue light from two first regions 131 horizontally adjacent to the second region 132, blue light from two fourth regions 134 vertically adjacent to the second region 132, and blue light from four third regions 133 diagonally adjacent to the second region 132 are incident on one blue pixel B.

[0090] 6D , for blue light, the color separation lens array 130 can function equivalently to an array of a plurality of microlenses ML1 arranged around the second photosensitive cell 112. Since each equivalent microlens ML1 is larger than the corresponding second photosensitive cell 112, it can focus not only the blue light incident on the region of the second photosensitive cell 112 but also the blue light incident on other regions surrounding the second photosensitive cell 112 onto the second photosensitive cell 112. For example, each microlens ML1 is about four times larger than the corresponding second photosensitive cell 112, and the four sides of each microlens ML1 are parallel to the four sides of the second photosensitive cell 112.

[0091] 7A and 7B are computer-generated images of the phase distribution of green light passing through a color separation lens array and the focusing distribution of green light in the opposing photosensitive cells. FIG. 7C illustrates an example of the traveling direction of green light incident on a first region and a fourth region of a color separation lens array corresponding to green pixels and their surroundings. FIG. 7D illustrates an example of a microlens array that acts equivalently to the color separation lens array with respect to green light.

[0092] Regarding the phase distribution illustrated in FIG. 7A, the phase at the center of the area corresponding to the green pixel G is approximately 2π, while the phase at the center of the areas corresponding to the adjacent blue pixel B and red pixel R shows approximately a π value.

[0093] Such a phase distribution can show a focusing distribution of green light as shown in Fig. 7B, where the green light is divided and focused in areas corresponding to two green pixels G, and almost no green light reaches areas corresponding to other pixels.

[0094] As a result, the green light that is incident on the first region 131 and the fourth region 134 corresponding to the green pixel G and their surroundings travels as shown in Fig. 7C after passing through the color separation lens array 130. For example, the green light of the incident light that is incident on the first region 131 of the color separation lens array 130 and parts of other regions surrounding the first region 131 is collected on the first photosensitive cell 111 immediately below the first region 131. In addition, although not shown, the green light of the incident light that is incident on the fourth region 134 of the color separation lens array 130 and parts of other regions surrounding the fourth region 134 is collected on the fourth photosensitive cell 114 immediately below the fourth region 134. In other words, one green pixel G is incident with green light coming from the first region 131 or fourth region 134 corresponding to that green pixel G, and green light coming from the first region 131 or fourth region 134, two second regions 132 adjacent to that green pixel G in the horizontal and vertical directions, and two third regions 133.

[0095] 7D , for green light, the color separation lens array 130 can function equivalently to an array of a plurality of microlenses ML2 arranged around the first and fourth photosensitive cells 111 and 114. Since each equivalent microlens ML2 is larger than the corresponding first or fourth photosensitive cell 111 or 114, it can focus not only the green light incident on the region of the first or fourth photosensitive cell 111 or 114 but also the green light incident on other regions surrounding the first or fourth photosensitive cell 111 or 114 onto the first or fourth photosensitive cell 111 or 114. For example, each microlens ML2 is twice as large as the corresponding first or fourth photosensitive cell 111 or 114 and is disposed adjacent to the corresponding first or fourth photosensitive cell 111 or 114 in the diagonal direction.

[0096] 8A and 8B are computer-generated images of the phase distribution of red light that has passed through a color separation lens array and the focusing distribution of the red light in the opposing photosensitive cells. FIG. 8C exemplarily illustrates the traveling direction of red light that has entered a third region of the color separation lens array corresponding to a red pixel and its periphery. FIG. 8D exemplarily illustrates a microlens array that functions equivalently to the color separation lens array with respect to a red pixel R.

[0097] Regarding the phase distribution illustrated in Figure 8A, the phase at the center of the area corresponding to the red pixel R is approximately 2π, the phase at the center of the area corresponding to the adjacent green pixel G exhibits approximately a π value, and the phase at the center of the area corresponding to the diagonal blue pixel B exhibits approximately a value smaller than π (e.g., approximately 0.2π to 0.7π).

[0098] Such a phase distribution can show a focusing distribution of red light as shown in Fig. 8B, where the red light is focused in an area corresponding to the red pixel R, and almost no red light reaches areas corresponding to other pixels.

[0099] As a result, the light that is incident on the third region 133 corresponding to the red pixel R and its periphery travels as shown in Fig. 8C after passing through the color separation lens array 130. For example, of the incident light that is incident on the third region 133 of the color separation lens array 130 and parts of the other regions surrounding the third region 133, the red light is focused on the third photosensitive cell 113 immediately below the third region 133. In other words, one red pixel R is incident with the red light coming from the third region 133 corresponding to that red pixel R, the red light coming from two fourth regions 134 that are horizontally adjacent to the third region 133, the red light coming from two first regions 131 that are vertically adjacent to the third region 133, and the red light coming from four second regions 132 that are diagonally adjacent to the third region 133.

[0100] 8D , for red light, the color separation lens array 130 can function equivalently to an array of a plurality of microlenses ML3 arranged around the third photosensitive cell 113. Since each equivalent microlens ML3 is larger than the corresponding third photosensitive cell 113, it can focus not only the red light incident on the region of the third photosensitive cell 113 but also the red light incident on other regions surrounding the third photosensitive cell 113 onto the third photosensitive cell 113. For example, each microlens ML3 is about four times larger than the corresponding third photosensitive cell 113, and the four sides of each microlens ML3 are parallel to the four sides of the third photosensitive cell 113.

[0101] 6C , 6D , 7C , 7D , 8C , and 8D can be expressed in a different way: of the incident light entering the first region 131 of the color separation lens array 130, the green light travels toward the center of the first photosensitive cell 111 corresponding to the first region 131, the blue light travels toward the center of the second photosensitive cell 112 around the first photosensitive cell 111 corresponding to the first region 131, and the red light travels toward the center of the third photosensitive cell 113 around the first photosensitive cell 111 corresponding to the first region 131. Of the incident light beams entering the second region 132 of the color separation lens array 130, the blue light beam travels toward the center of the second photosensitive cell 112 corresponding to the second region 132, the green light beam travels toward the center of the first photosensitive cell 111 and the fourth photosensitive cell 114 around the second photosensitive cell 112 corresponding to the second region 132, and the red light beam travels toward the center of the third photosensitive cell 113 around the second photosensitive cell 112 corresponding to the second region 132. Similarly, of the incident light beams entering the third region 133 of the color separation lens array 130, the red light beam travels toward the center of the third photosensitive cell 113 corresponding to the third region 133, the green light beam travels toward the center of the first photosensitive cell 111 and the fourth photosensitive cell 114 around the third photosensitive cell 113 corresponding to the third region 133, and the blue light beam travels toward the center of the second photosensitive cell 112 around the third photosensitive cell 113 corresponding to the third region 133. Finally, of the incident light beams entering the fourth region 134 of the color separation lens array 130, the green light beams travel toward the central portions of the fourth photosensitive cells 114 corresponding to the fourth region 134, the blue light beams travel toward the central portions of the second photosensitive cells 112 around the fourth photosensitive cells 114 corresponding to the fourth region 134, and the red light beams travel toward the central portions of the third photosensitive cells 113 around the fourth photosensitive cells 114 corresponding to the fourth region 134.

[0102] Such color separation and light collection can be achieved more effectively by appropriately setting the thickness of the spacer layer 120. For example, the theoretical thickness of the spacer layer 120 is t , λ 0 If the refractive index of the spacer layer 120 for a wavelength is n and the pitch of the photosensitive cells is p, then the following Equation 1 can be satisfied:

[0103]

number

[0104] Here, the theoretical thickness h of the spacer layer 120 t is λ 0 In other words, λ 1 means the focal length at which light having a wavelength of λ 2 is focused by the color separation lens array 130 onto the upper surfaces of the photosensitive cells 111, 112, 113, and 114. 0 While passing through the color separation lens array 130, the light having a wavelength of h t It can be focused at a distance of about

[0105] As described in Equation 1, the theoretical thickness h t also depends on the pitch p of the photosensitive cells 111, 112, 113, and 114 and the refractive index n of the spacer layer 120. For example, 0 Assuming that the wavelength of the photosensitive cells 111, 112, 113, and 114 is 540 nm, the pitch p of the photosensitive cells 111, 112, 113, and 114 is 0.8 μm, and the refractive index n of the spacer layer 120 at a wavelength of 540 nm is 1.46, then the theoretical thickness h of the spacer layer 120 is t In other words, the distance between the lower surface of the color separation lens array 130 and the upper surface of the sensor substrate 110 is about 1.64 μm. However, the actual thickness of the spacer layer 120 is smaller than the theoretical thickness h t For example, in consideration of the efficiency of the color separation lens array 130, the theoretical thickness h t Based on this, the actual thickness of the spacer layer 120 can be selected within a predetermined range.

[0106] 9A to 9E are graphs illustrating an example of a change in efficiency of the color separation lens array 130 depending on 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. Fig. 9A shows the light-collecting efficiency of the color separation lens array 130 for blue light incident on the second photosensitive cell 112 from the first region 131 to the fourth region 134 constituting the unit pattern array of the color separation lens array 130, Fig. 9B shows the light-collecting efficiency of the color separation lens array 130 for green light incident on the first photosensitive cell 111 and the fourth photosensitive cell 114 from the first region 131 to the fourth region 134 constituting the unit pattern array, and Fig. 9C shows the light-collecting efficiency of the color separation lens array 130 for red light incident on the third photosensitive cell 113 from the first region 131 to the fourth region 134 constituting the unit pattern array.

[0107] 9A and 9C, four regions are arranged for one photosensitive cell, so the theoretical maximum value is 4. In the case of FIG. 9B, four regions are arranged for two photosensitive cells, so the theoretical maximum value is 2. In the graphs of FIGS. 9A to 9C, the distance at which the light-collecting efficiency of the color separation lens array 130 is at the theoretical thickness h that satisfies Equation 1 is t As shown in FIG. 9A to FIG. 9C, the theoretical thickness h t varies slightly depending on the wavelength.

[0108] FIG. 9D is a graph showing an example of the efficiency change of a color separation lens array considering the sensitivity characteristics of the human eye to visible light. For example, the human eye is generally most sensitive to green light and least sensitive to blue light. Therefore, the graph of FIG. 9D can be obtained by giving the lowest weight to the graph of FIG. 9A, giving a weight higher than blue light to the graph of FIG. 9C, and giving the highest weight to the graph of FIG. 9B, and then averaging the sum of the weights. FIG. 9E is a graph showing the result of normalizing the graph of FIG. 9D.

[0109] 9D and 9E, when the pitch of the photosensitive cells 111, 112, 113, and 114 is 0.7 μm, the efficiency of the color separation lens array 130 for all visible light rays taking into account the sensitivity characteristics of the human eye is highest at a distance of about 1.2 μm. Also, the efficiency of the color separation lens array 130 is 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.

[0110] 10A to 10E are graphs illustrating an example of a change in efficiency of the color separation lens array 130 depending on 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. Referring to FIG. 10A to 10E, when the pitch of the photosensitive cells 111, 112, 113, and 114 is 0.8 μm, the efficiency of the color separation lens array 130 for all visible light rays taking into account the sensitivity characteristics of the human eye is highest at a distance of about 1.64 μm. In addition, the efficiency of the color separation lens array 130 is 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.

[0111] 11A to 11E are graphs illustrating an example of a change in efficiency of the color separation lens array 130 depending on 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. Referring to FIG. 11A to 11E, when the pitch of the photosensitive cells 111, 112, 113, and 114 is 1.0 μm, the efficiency of the color separation lens array 130 for all visible light rays taking into account the sensitivity characteristics of the human eye is highest at a distance of about 2.6 μm. In addition, the efficiency of the color separation lens array 130 is 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.

[0112] As a result, it can be seen that even if the actual thickness h of the spacer layer 120 is larger or smaller than the theoretical thickness ht of Equation 1 by the pitch p of the photosensitive cells 111, 112, 113, and 114, the color separation lens array 130 still has a high efficiency of 80% or more, 90% or more, or 95% or more of the maximum efficiency. Considering the above results, the actual thickness h of the spacer layer 120 is h t -p≦h≦h t It is also selected within the range of +p.

[0113] The color separation lens array 130 does not absorb or block incident light, but splits it according to wavelength and collects the split light in a specific area, thereby improving the light utilization efficiency of the image sensor. In addition, since the color separation lens array 130 has an improved color separation performance, an image sensor using the color separation lens array 130 can have excellent color purity. In addition, the image sensor using the color separation lens array 130 can maintain the Bayer pattern method that is generally adopted in image sensors, and can utilize the same image processing algorithm as the existing pixel structure. In addition, since the color separation lens array 130 can also function as a lens that collects incident light, the image sensor using the color separation lens array 130 does not require a separate microlens for collecting light to each pixel.

[0114] 12 is a perspective view showing an exemplary shape of a nanopost that may be employed in a color separation lens array according to an embodiment. Referring to FIG. 12, the nanopost may have a cylindrical shape with a diameter D and a height H. The diameter D and / or the height H may have a sub-wavelength value, and the diameter D may vary depending on the position where the nanopost is disposed.

[0115] Nanoposts can also be formed by posts having various cross-sectional shapes. Figures 13A to 13H are plan views showing exemplary shapes of nanoposts that can be employed in a color separation lens array of an image sensor.

[0116] As shown in FIG. 13A, the cross-sectional shape of the nanopost may be a circular ring with an outer diameter D and an inner diameter Di. The width w of the ring may have a sub-wavelength value. As shown in FIG. 13B, the cross-sectional shape of the nanopost may be an ellipse with different major and minor axis lengths Dx, Dy in the first direction (X direction) and the second direction (Y direction). Such a shape may also be adopted for the first region 131 and the fourth region 134 corresponding to the green pixel, as mentioned when describing the embodiment of FIG. 5B.

[0117] Furthermore, the cross-sectional shape of the nanopost may be a square, a square ring, or a cross as shown in Figures 13C, 13D, and 13F, or a rectangle or a cross with different lengths Dx and Dy in the first direction (X direction) and the second direction (Y direction) as shown in Figures 13E and 13G. Such a rectangle or cross shape is also adopted for the first region 131 and the fourth region 134 corresponding to the green pixel, as mentioned in the description of the embodiment of Figure 5B.

[0118] As another example, the cross-sectional shape of the nanopost can have a plurality of concave arcs, as shown in FIG. 13H.

[0119] FIG. 14 is a plan view illustrating an example of an arrangement of nanoposts forming a color separation lens array according to another embodiment.

[0120] The color separation lens array 140 may have a shape corresponding to the pixel arrangement of the Bayer pattern illustrated in FIG. 2A, and may include a region divided into four regions: a first region 141 corresponding to a green pixel G, a second region 142 corresponding to a blue pixel B, a third region 143 corresponding to a red pixel R, and a fourth region 144 corresponding to a green pixel G. Although not illustrated, such unit pattern arrays may be arranged by repeating them along a first direction (X direction) and a second direction (Y direction). Each region may be equally divided into a plurality of subregions, and nanoposts NPs may be arranged at the intersections of the subregion boundaries. FIG. 14 shows an example in which the number of subregions is nine, and nanoposts NPs are arranged on lattice points dividing the nine subregions, and no nanoposts NPs are arranged in the center of each of the regions 141, 142, 143, and 144, with four nanoposts NPs of the same size forming the center. The nanoposts NPs in the peripheral regions are arranged on the boundary lines with other regions. The nanoposts NPs are labeled r1 to r9 according to their detailed positions within the unit pattern array.

[0121] 14, the nanopost r1 arranged at the center of the first region 141 corresponding to the green pixel has a larger cross-sectional area than the nanoposts r5, r6, and r9 arranged at the periphery, and the nanopost r4 arranged at the center of the fourth region 144 corresponding to the green pixel has a larger cross-sectional area than the nanoposts r7, r8, and r9 arranged at the periphery. The cross-sectional size of the nanoposts r1 and r4 arranged at the centers of the first region 141 and the fourth region 144 corresponding to the green pixel is also larger than the cross-sectional size of the nanopost r2 arranged at the center of the second region 142 corresponding to the blue pixel and the nanopost r3 arranged at the center of the third region 143 corresponding to the red pixel. Also, the cross-sectional area of ​​the nanopost r2 arranged at the center of the second region 142 corresponding to the blue pixel is also larger than the cross-sectional area of ​​the nanopost r3 arranged at the center of the third region 143 corresponding to the red pixel.

[0122] The nanoposts NP in the second region 142 and the third region 143 are also arranged symmetrically along the first direction (X direction) and the second direction (Y direction), and the nanoposts NP in the first region 141 and the fourth region 144 are also arranged asymmetrically along the first direction (X direction) and the second direction (Y direction). In other words, the nanoposts NP in the second region 142 and the third region 143 corresponding to blue pixels and red pixels, respectively, can have the same distribution rule along the first direction (X direction) and the second direction (Y direction), and the nanoposts NP in the first region 141 and the fourth region 144 corresponding to green pixels can have different distribution rules along the first direction (X direction) and the second direction (Y direction).

[0123] Among the nanoposts NP, the cross-sectional area of ​​nanopost r5 located at the boundary between the first region 141 and the second region 142 adjacent thereto in the first direction (X direction) is different from the cross-sectional area of ​​nanopost r6 located at the boundary between the first region 141 and the third region 143 adjacent thereto in the second direction (Y direction). Also, the cross-sectional area of ​​nanopost r7 located at the boundary between the fourth region 144 and the third region 143 adjacent thereto in the first direction (X direction) is different from the cross-sectional area of ​​nanopost r8 located at the boundary between the fourth region 144 and the second region 142 adjacent thereto in the second direction (Y direction).

[0124] On the other hand, the cross-sectional area of ​​nanopost r5 located at the boundary between the first region 141 and the second region 142 adjacent to it in the first direction (X direction) is identical to the cross-sectional area of ​​nanopost r8 located at the boundary between the fourth region 144 and the second region 142 adjacent to it in the second direction (Y direction), and the cross-sectional area of ​​nanopost r6 located at the boundary between the first region 141 and the third region 143 adjacent to it in the second direction (Y direction) is identical to the cross-sectional area of ​​nanopost r7 located at the boundary between the fourth region 144 and the third region 143 adjacent to it in the first direction (X direction).

[0125] On the other hand, nanoposts r9 arranged at the corners of the first region 141, the second region 142, the third region 143, and the fourth region 144, ie, at the positions where the four regions intersect, have the same cross-sectional area.

[0126] Thus, in the second region 142 and the third region 143 corresponding to the blue pixel and the red pixel, respectively, the nanoposts NP are arranged in a four-fold symmetric form, and in the first and fourth regions 141 and 144 corresponding to the green pixel, the nanoposts NP are arranged in a two-fold symmetric form, the first region 141 and the fourth region 144 being rotated 90° with respect to each other. Such a form is also shown in the embodiments of Figures 16 and 17 described later.

[0127] FIG. 15 is a plan view illustrating an exemplary arrangement of nanoposts constituting a color separation lens array according to still another embodiment.

[0128] The color separation lens array 150 may have a shape corresponding to the pixel arrangement of the Bayer pattern, and may include an area divided into a first area 151 corresponding to green pixels, a second area 152 corresponding to blue pixels, a third area 153 corresponding to red pixels, and a fourth area 154 corresponding to green pixels.

[0129] Each region is also divided into a number of subregions, and nanoposts NPs can be placed at the intersections of the boundaries of the subregions. Fig. 15 differs from the nanostructure array in Fig. 14 in that it shows an example in which the number of subregions is 16, and nanoposts NPs are placed on the lattice points dividing the subregions into 16, with nanoposts NPs placed in the center of each of the regions 151, 152, 153, and 154. The nanoposts NPs are indicated as s1 to s11 according to their detailed positions within the unit pattern array.

[0130] In the embodiment of FIG. 15, nanopost s1 located in the center of first region 151 corresponding to a green pixel and nanopost s4 located in the center of fourth region 154 have larger cross-sectional areas than the nanoposts NP located on the periphery, and can also have larger cross-sectional areas than the nanoposts NP located in second region 152 corresponding to a blue pixel and third region 153 corresponding to a red pixel.

[0131] In the first region 151, the nanopost s1 with the largest cross-sectional area is arranged in the center, and the nanoposts s10, s5, and s6 with gradually smaller cross-sectional areas are arranged toward the periphery. In the fourth region 154, the nanopost s4 with the largest cross-sectional area is arranged in the center, and the nanoposts s11, s7, and s8 with gradually smaller cross-sectional areas are arranged toward the periphery. In contrast, in the second region 152, nine nanoposts s2 with the same cross-sectional area are arranged in the center, and nanoposts s5 and s8 with larger cross-sectional areas are arranged in the periphery. In the third region 153, nine nanoposts s3g with the same cross-sectional area are arranged in the center, and nanoposts s6 and s7 with larger cross-sectional areas are arranged in the periphery. In the second region 152 and the third region 153, the nanoposts NP in the periphery are arranged on the borders with the other regions.

[0132] 14, in the embodiment of Fig. 15, the nanoposts NP in the second region 152 and the third region 153 are also arranged symmetrically along the first direction (X direction) and the second direction (Y direction), and the nanoposts NP in the first region 151 and the fourth region 154 are also arranged asymmetrically along the first direction (X direction) and the second direction (Y direction). Also, the nanoposts s9 arranged at the corners of the first region 151, the second region 152, the third region 153, and the fourth region 154, i.e., at positions where the four regions are adjacent, have the same cross-sectional area.

[0133] FIG. 16 is a plan view illustrating an exemplary arrangement of nanoposts constituting a color separation lens array according to yet another embodiment.

[0134] The color separation lens array 160 may have a shape corresponding to the pixel arrangement of the Bayer pattern, and may include an area divided into a first area 161 corresponding to green pixels, a second area 162 corresponding to blue pixels, a third area 163 corresponding to red pixels, and a fourth area 164 corresponding to green pixels.

[0135] Each region is also divided into a number of subregions, and nanopost NPs can be arranged within the subregions. In the color separation lens array 160, each region is divided into nine subregions, similar to that in Fig. 14, but the difference is that the nanopost NPs are arranged inside the subregions, not at the intersections between the subregions. The nanopost NPs are indicated as t1 to t16 according to their detailed positions within the unit pattern array.

[0136] In the embodiment of Figure 16, nanopost t1 located at the center of the first region 161 and nanopost t4 located at the center of the fourth region 164 have cross-sectional sizes larger than not only the nanoposts NP located in their peripheral areas but also the nanoposts NP located in the second region 162 and the third region 163.

[0137] The cross-sectional area of ​​the nanopost t2 disposed at the center of the second region 162 is larger than the cross-sectional area of ​​the nanopost t3 disposed at the center of the third region 163. In the case of the second region 162, the cross-sectional areas of the nanoposts t6 and t10 disposed at the periphery spaced apart from the center in the first direction (X direction) and the second direction (Y direction) are larger than the cross-sectional area of ​​the central nanopost t2, whereas the cross-sectional area of ​​the nanopost t14 disposed at the periphery spaced apart from the center in the diagonal direction is smaller than the cross-sectional area of ​​the central nanopost t2.

[0138] In the third region 163, the central nanopost t3 has the smallest cross-sectional area, and the peripheral nanoposts t7, t11, and t15 all have cross-sectional areas larger than that of the central nanopost t3.

[0139] The nanoposts NP in the second region 162 and the third region 163 are also arranged symmetrically along the first direction (X direction) and the second direction (Y direction), and the nanoposts NP arrangement in the first region 161 and the fourth region 164 is also arranged asymmetrically along the first direction (X direction) and the second direction (Y direction). In other words, the nanoposts NP in the second region 162 and the third region 163 corresponding to blue pixels and red pixels, respectively, show the same distribution pattern along the first direction (X direction) and the second direction (Y direction), and the nanoposts NP in the first region 161 and the fourth region 164 corresponding to green pixels show different distribution patterns along the first direction (X direction) and the second direction (Y direction).

[0140] In the first region 161, the central nanopost t1 has a different cross-sectional area from the nanopost t5 adjacent thereto in the first direction (X direction) and the nanopost t9 adjacent thereto in the second direction (Y direction). Similarly, in the fourth region 164, the central nanopost t4 has a different cross-sectional area from the nanopost t8 adjacent thereto in the first direction (X direction) and the nanopost t12 adjacent thereto in the second direction (Y direction). Also, the nanopost t1 at the center of the first region 161 and the nanopost t5 adjacent thereto in the first direction (X direction) have the same cross-sectional area as the nanopost t4 at the center of the fourth region 164 and the nanopost t12 adjacent thereto in the second direction (Y direction), and the nanopost t1 at the center of the first region 161 and the nanopost t9 adjacent thereto in the second direction (Y direction) have the same cross-sectional area as the nanopost t4 at the center of the fourth region 164 and the nanopost t8 adjacent thereto in the first direction (X direction). The nanopost t13 adjacent to the corner of the first region 161 and the nanopost t16 adjacent to the corner 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° with respect to each other.

[0141] In the second region 162, the nanopost t6 adjacent to the central nanopost t2 in the first direction (X direction) and the nanopost t10 adjacent to the central nanopost t2 in the second direction (Y direction) have the same cross-sectional area. The nanopost t14 adjacent to the corner of the second region 162 has the same cross-sectional area.

[0142] In the third region 163, the nanopost t7 adjacent to the central nanopost t3 in the first direction (X direction) and the nanopost t11 ​​adjacent to the central nanopost t3 in the second direction (Y direction) have the same cross-sectional area. The nanopost t15 adjacent to the corner of the third region 163 have the same cross-sectional area.

[0143] FIG. 17 is a plan view illustrating an example of a configuration of a plurality of nanoposts forming a color separation lens array according to yet another embodiment.

[0144] The color separation lens array 170 of the image sensor of this embodiment has the simplest structure. One nanopost NP is arranged in each of the first region 171 corresponding to the green pixels, the second region 172 corresponding to the blue pixels, the third region 173 corresponding to the red pixels, and the fourth region 174 corresponding to the green pixels. The cross-sectional area of ​​the nanopost NP in the first region 171 and the fourth region 174 is the largest, the cross-sectional area of ​​the nanopost NP in the second region 172 is smaller than the cross-sectional area of ​​the nanopost NP in the first region 171, and the cross-sectional area of ​​the nanopost NP in the third region 173 is the smallest.

[0145] FIG. 18 is a graph showing an example of the spectral distribution of light incident on each of the red, green, and blue pixels R, G, and B of an image sensor including the color separation lens array of FIG.

[0146] 19A and 19B are cross-sectional views showing a schematic structure of a pixel array according to another embodiment, taken along different cross sections.

[0147] 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 is also disposed between the sensor substrate 110 and the spacer layer 120.

[0148] The pixel array 1100a may further include a transparent dielectric layer 121 that protects the color separation lens array 130. The dielectric layer 121 is also disposed to cover the spaces between adjacent nanopost NPs and the top surfaces of the nanopost NPs. The dielectric layer 121 may be made of a material having a refractive index lower than that of the nanopost NPs, for example, the same material as the spacer layer 120.

[0149] The color filter 105 has filter regions in a shape corresponding to the pixel arrangement of the Bayer pattern. As shown in FIG. 19A, green filter regions CF1 and blue filter regions CF2 are alternately arranged, and as shown in FIG. 19B, red filter regions CF3 and green filter regions CF1 are alternately arranged in a row spaced apart in the Y direction. The color filter 105 is not an essential component in that the color separation lens array 130 splits and focuses light of different wavelengths into the photosensitive cells 111, 112, 113, and 114. However, by providing the additional color filter 105 in this way, color purity is complemented, and light that has been color-separated to a considerable extent is incident on the color filter 105, so that light loss is not large.

[0150] 20 and 21 are graphs showing exemplary spectral distributions of light incident on the red pixel R, green pixel G, and blue pixel B of an image sensor, respectively showing the spectral distributions of an embodiment having a color filter and an embodiment having no color filter.

[0151] The graph in Figure 20 is the spectrum of the image sensor equipped with the color filters shown in Figures 19A and 19B, and the graph in Figure 21 is the spectrum of the image sensor without the color filters shown in Figures 4A and 4B. Figures 20 and 21 are simulation results for an image sensor with a pixel width of about 0.7 μm, and when a color filter is provided, the overall amount of light tends to be lower, but the color separation performance is improved compared to the comparative example.

[0152] The image sensor including the color separation lens array according to the above-described embodiment can be applied to various optical devices such as a camera. For example, FIG. 22 is a conceptual diagram showing a camera according to an embodiment.

[0153] 22, the camera 2000 according to an embodiment may include an objective lens 2010 that forms an optical image by converging light reflected from an object, and an image sensor 1000 that converts the optical image formed by the objective lens 2010 into an electrical image signal. The image sensor 1000 includes the above-mentioned color separation lens array. The camera 2000 further includes a processor 2200 that processes an electrical signal output from the image sensor 1000 into an image signal. The processor 2200 performs operations such as noise removal and color interpolation on the color-specific signals output from the image sensor 1000 to form an image. Although not shown, the camera 2000 may further include an infrared blocking filter disposed between the image sensor 1000 and the objective lens 2010, a display panel that displays an image formed by the processor 2200, and a memory that stores image data formed by the processor 2200. Such a camera 2000 may also be mounted in a mobile electronic device, such as a mobile phone, a notebook computer, or a tablet personal computer (PC).

[0154] The objective lens 2010 serves to focus an image of a subject outside the camera 2000 onto the image sensor 1000. If 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 further focused at a point on the image sensor 1000 via the objective lens 2010. For example, light originating from a point A on the optical axis OX passes through the objective lens 2010 and is focused at the center of the image sensor 1000 on the optical axis OX. Light originating from points B, C, and D off the optical axis OX cross the optical axis OX by the objective lens 2010 and is focused at a point on the periphery of the image sensor 1000. 22, for example, light starting from point B above the optical axis OX crosses the optical axis OX and collects at the lower end of the image sensor 1000, while light starting from point C below the optical axis OX crosses the optical axis OX and collects at the upper end of the image sensor 1000. Light starting from point D located between the optical axis OX and point B collects between the center and the lower end of the image sensor 1000.

[0155] Therefore, the light beams starting from different points A, B, C, and D respectively enter the image sensor 1000 at different angles depending on the distance between the points A, B, C, and D and the optical axis OX. The angle of incidence of the light beams entering the image sensor 1000 is generally defined as the chief ray angle (CRA). The chief ray means a light beam that starts from a point on the subject, passes through the center of the objective lens 2010, and enters the image sensor 1000, and the chief ray angle means an angle that the chief ray makes with the optical axis OX. The light beams starting from a point A on the optical axis OX have a chief ray angle of 0° and enter the image sensor 1000 perpendicularly. The farther the starting point is from the optical axis OX, the greater the chief ray angle becomes.

[0156] From the viewpoint of image sensor 1000, the chief ray angle of light incident on the center of image sensor 1000 is 0°, and the chief ray angle of the incident light increases toward the edge of image sensor 1000. For example, the chief ray angle of light starting from point B and point C and incident on the outermost edge of image sensor 1000 is the largest, and the chief ray angle of light starting from point A and incident on the center of image sensor 1000 is 0°. In addition, the chief ray angle of light starting from point D and incident between the center and the edge of image sensor 1000 is smaller than the chief ray angle of light starting from point B and point C, and is greater than 0°.

[0157] However, the color separation lens array may generally have a directionality. In other words, the color separation lens array operates efficiently for light incident in a specific angle range, but if the incident angle is far from the specific angle range, the color separation performance of the color separation lens array is degraded. Therefore, if the nanoposts of the color separation lens array have the same arrangement form in the entire region of the image sensor 1000, the color separation efficiency is not uniform in the entire region of the image sensor 1000, and the color separation efficiency differs depending on the region of the image sensor 1000. As a result, the quality of the image provided by the camera 2000 is degraded.

[0158] Therefore, the arrangement of the nanoposts of the color separation lens array can be designed to be different in consideration of the chief ray angle of the incident light which varies depending on the position on the image sensor 1000. For example, Figs. 23A to 23C are schematic plan views showing the change in the arrangement of the nanoposts of the color separation lens array depending on the position on the image sensor. In particular, Fig. 23A shows the positions of the nanoposts NP arranged at the center of the image sensor 1000, Fig. 23B shows the positions of the nanoposts NP arranged between the center and the edge of the image sensor 1000, and Fig. 23C shows the positions of the nanoposts NP arranged at the edge of the image sensor 1000. Figs. 23A to 23C are not intended to limit the specific arrangement of the nanoposts NP, but are merely intended to conceptually explain the relative positional change of the nanoposts NP depending on the position on the image sensor 1000.

[0159] 23A to 23C, the first, second, third and fourth regions of the color separation lens array may be shifted farther from the corresponding pixels or photosensitive cells from the center of the image sensor 1000 toward the edge. For example, the positions of the first, second, third and fourth regions of the color separation lens array may coincide with the positions of the corresponding green, blue, red and green pixels (or the positions of the corresponding photosensitive cells) at the center of the image sensor 1000, the center of the color separation lens array or the center of the sensor substrate. The first, second, third and fourth regions of the color separation lens array may be shifted farther from the positions of the corresponding green, blue, red and green pixels (or the positions of the corresponding photosensitive cells) from the center of the image sensor 1000, the center of the color separation lens array or the center of the sensor substrate. The degree to which the first, second, third and fourth regions of the color separation lens array are shifted is also determined by the angle of the chief ray of light incident on the color separation lens array. In particular, in the periphery of the image sensor 1000, the periphery of the color separation lens array or the periphery of the sensor substrate, the first, second, third and fourth regions of the color separation lens array are shifted toward the center of the image sensor 1000 with respect to the first, second, third and fourth photosensitive cells corresponding thereto, respectively.

[0160] In the following, for convenience, the center of the image sensor 1000 is referred to as the center of the image sensor 1000, but since the image sensor 1000, the color separation lens array, and the sensor substrate are arranged opposite each other, the center of the image sensor 1000 can also mean the center of the color separation lens array or the center of the sensor substrate. Similarly, in the following, the periphery / edge of the image sensor 1000 can also mean the periphery / edge of the color separation lens array or the periphery / edge of the sensor substrate.

[0161] FIG. 24 is a cross-sectional view showing a schematic structure of a pixel array according to another embodiment.

[0162] 24, the pixel array 1100b of the image sensor of this embodiment is different from the previous embodiment in that it includes a color separation lens array 230 having nanoposts NP stacked in two stages. The nanoposts NP may include a first nanopost NP1 arranged on the spacer layer 120 and a second nanopost NP2 arranged on the first nanopost NP1. The second nanopost NP2 is also shifted along the inclination direction of the light with respect to the first nanopost NP1. For example, when the light incident on the color separation lens array 230 is inclined from the right side to the left side, the second nanopost NP2 is also shifted to the right with respect to the first nanopost NP1. Conversely, when the light incident on the color separation lens array 230 is inclined from the left side to the right side, the second nanopost NP2 is also shifted to the left with respect to the first nanopost NP1.

[0163] 22, the second nanopost NP2 is also shifted relative to the first nanopost NP1 toward the center of the image sensor 1000. For example, from the center of the image sensor 1000 toward the left end, the second nanopost NP2 is shifted further to the right relative to the first nanopost NP1, and from the center of the image sensor 1000 toward the right end, the second nanopost NP2 is shifted further to the left relative to the first nanopost NP1.

[0164] Similarly, the third region 233 and the fourth region 234 of the color separation lens array 230 are shifted toward the center of the image sensor 1000 relative to their corresponding red pixels (or third photosensitive cells) and green pixels (or fourth photosensitive cells). For example, from the center to the left end of the image sensor 1000, the third region 233 and the fourth region 234 of the color separation lens array 230 are shifted further to the right relative to their corresponding green pixels and red pixels. Although not shown, the first region and the second region arranged on another cross section of the color separation lens array 230 are also shifted toward the center of the image sensor 1000 relative to their corresponding green pixels (or first photosensitive cells) and blue pixels (or second photosensitive cells).

[0165] In particular, the third region 233 and the fourth region 234 of the color separation lens array 230 are also shifted so as to focus the red light and the green light, respectively, on the central portions of the corresponding third photosensitive cells 113 and fourth photosensitive cells 114. The distance s by which the third region 233 and the fourth region 234 of the color separation lens array 230 are shifted is also determined by, for example, the following Equation 2:

[0166]

number

[0167] In Equation 2, d is the shortest linear distance or interval between the lower surface of the color separation lens array 230 and the upper surface of the sensor substrate 110, and CRA' is the angle of incidence of light incident on the sensor substrate 110. CRA' is also determined by Equation 3 below.

[0168]

number

[0169] In Equation 3, CRA is the angle of incidence 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. Therefore, the distance s by which the third region 233 and the fourth region 234 of the color separation lens array 230 are shifted from the corresponding pixels is determined by the angle of incidence of light incident on the color separation lens array 230 and the refractive index of the material disposed between the color 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, CRA' can be determined by considering the angle of incidence of light incident on the spacer layer 120 and the refractive index of the spacer layer 120, the angle of incidence of light incident on the color filter 105 and the refractive index of the color filter 105.

[0170] FIG. 25 is a plan view illustratively showing the shift pattern of two-dimensionally arranged nanoposts in a color separation lens array applied to the image sensor of the camera shown in FIG. 22, and FIG. 26 is a cross-sectional view showing a schematic structure of a pixel array having the color separation lens array shown in FIG. 25.

[0171] 25 and 26, in the center C of the image sensor 1000, the first to fourth regions of the color separation lens array 230 are not shifted with respect to the corresponding pixels (or photosensitive cells). In addition, in the center C of the image sensor 1000, the second nanopost NP2 is not shifted with respect to the first nanopost NP1. In the peripheral portion P of the image sensor 1000, the first to fourth regions of the color separation lens array 230 are shifted toward the center 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. Therefore, in the case of the image sensor 1000 used in the camera 2000 illustrated in FIG. 22, the total area of ​​the color separation lens array 230 is smaller than the total area of ​​the pixel array 1100b of the image sensor 1000 or the total area of ​​the sensor substrate 110.

[0172] On the other hand, in the embodiment of Figure 24, a color filter 105 is disposed on the sensor substrate 110, but if the color separation lens array 230 has sufficient performance in the peripheral portion P of the image sensor 1000, the color filter 105 may be omitted, as shown in Figure 26.

[0173] 27 is a perspective view showing 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 nanopost NP1 and the upper second nanopost NP2 are stacked so as to be offset from each other. The offset is indicated by b in FIG. 27, and the magnitude of the offset increases from the center C to the peripheral portion P of the image sensor 1000, i.e., along the radial direction. The second nanopost NP2 is offset from the first nanopost NP1 in the direction from the peripheral portion P toward the center C. In particular, the offset b is determined so that light is incident on the center of the upper surface of the second nanopost NP2 and light is incident on the center of the upper surface of the first nanopost NP1.

[0174] 26, in order to manufacture the nanoposts NP in such a structure, the dielectric layer 121 may include a first dielectric layer 121a disposed on the spacer layer 120, filling the spaces between the first nanoposts NP1 and supporting the second nanoposts NP2, and a second dielectric layer 121b covering the second nanoposts NP2. The first dielectric layer 121a and the second dielectric layer 121b are also formed from a material having a refractive index lower than that of the material forming the first nanoposts NP1 and the second nanoposts NP2.

[0175] Although the structure in which the nanoposts NP are stacked in two layers is illustrated, the present invention is not limited thereto, and a structure of three or more layers may be used. For example, FIG. 28 is a cross-sectional view showing a schematic structure of a pixel array according to another embodiment.

[0176] 28, the pixel array 1100c of the image sensor includes a color separation lens array 240 having nanoposts NP stacked in three stages. The nanoposts NP may include a first nanopost NP1 arranged on the spacer layer 120, a second nanopost NP2 arranged on the first nanopost NP1, and a third nanopost NP3 arranged on the second nanopost NP2. The second nanopost NP2 is shifted toward the center of the image sensor relative to the first nanopost NP1, and the third nanopost NP3 is shifted toward the center of the image sensor relative to the second nanopost NP2.

[0177] In addition, the fourth region 244 of the color separation lens array 240 is shifted toward the center of the image sensor relative to the corresponding green pixel or fourth photosensitive cell 114, and the third region 243 is shifted toward the center of the image sensor relative to the corresponding red pixel or third photosensitive cell 113.

[0178] 29A to 29C are graphs showing exemplary spectral distributions of light incident on red, green, and blue pixels of an image sensor according to an embodiment, respectively, in cases where a change in the chief ray angle due to the position on the image sensor is not taken into consideration, a change in the chief ray angle is taken into consideration, a change in the nanopost position is taken into consideration, and nanoposts are arranged in two stages in consideration of a change in the chief ray angle. In Figs. 29A to 29C, the graph marked B0 is the spectral distribution of light incident on a blue pixel when the chief ray angle is 0°, the graph marked G0 is the spectral distribution of light incident on a green pixel when the chief ray angle is 0°, and the graph marked R0 is the spectral distribution of light incident on a red pixel when the chief ray angle is 0°. In addition, the graph indicated by B26 is the spectral distribution of light incident on a blue pixel when the chief ray angle is 26°, the graph indicated by Gb26 is the spectral distribution of light incident on a blue pixel and a green pixel arranged alternately with it in the first direction when the chief ray angle is 26°, the graph indicated by Gr26 is the spectral distribution of light incident on a red pixel and a green pixel arranged alternately with it in the first direction when the chief ray angle is 26°, and the graph indicated by R26 is the spectral distribution of light incident on a red pixel when the chief ray angle is 0°.

[0179] As shown in the graph of Fig. 29A, if the change in the chief ray angle is not taken into consideration, the performance of the color separation lens array for light with a chief ray angle of 26° is degraded. And, as shown in the graph of Fig. 29B, if the nanoposts are shifted while taking into consideration the change in the chief ray angle, the performance of the color separation lens array for light with a chief ray angle of 26° is improved. Also, as shown in the graph of Fig. 29C, if the nanoposts are arranged in two stages together with the shifting of the nanoposts, the performance of the color separation lens array for light with a chief ray angle of 26° is further improved, becoming almost close to the performance of the color separation lens array for light with a chief ray angle of 0°.

[0180] 30A and 30B are plan views showing changes in nanopost line width depending on the position on an image sensor according to another embodiment. FIG. 30A illustrates the line width of the nanoposts NP of a color separation lens array at the center of the image sensor, and FIG. 30B illustrates the line width of the nanoposts NP' of a color separation lens array at the periphery of the image sensor. In the embodiment illustrated in FIG. 30B, the position of the nanoposts is shifted with respect to the corresponding pixel, and the line width of the nanoposts NP' is further changed by shifting the second nanopost NP2' with respect to the first nanopost NP1'. The change in the line width of the nanoposts NP' is also determined by the chief ray angle as shown in the following Equation 4.

[0181]

number

[0182] 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. Therefore, the line width of the nanopost NP' increases toward the periphery of the image sensor. For convenience, FIG. 30B shows an exaggerated increase in the line width of the nanopost NP'. The line width of the nanopost NP' at the outermost edge of the image sensor can increase by about 2.5% to 6.5% compared to the line width at the center of the image sensor.

[0183] Here, the line width change is a comparison of the line widths of nanoposts arranged at the same position in the same region among the first, second, third, and fourth regions of the color separation sensor array. For example, the line width of a nanopost arranged at the center of the first region of the color separation sensor array at the center of the image sensor can be compared with the line width of a nanopost arranged at the center of the first region of the color separation sensor array at the periphery of the image sensor. Nanoposts arranged in different regions of the color separation sensor array, or nanoposts arranged at different positions in the same region, are not subject to line width comparison.

[0184] Figure 31 is a graph showing an example of the spectral distribution of light incident on the red, green, and blue pixels of the image sensor shown in Figure 30. Comparing the graph of Figure 31 with the graph of Figure 29C, it can be seen that the performance of the color separation lens array for light with a chief ray angle of 26° is further improved when the line width of the nanoposts is further changed along with the shift of the nanoposts and the two-stage structure of the nanoposts.

[0185] 32 and 33 are plan views showing various shapes of nanoposts employed in a color separation lens array according to another embodiment. As shown in Fig. 32 and Fig. 33, nanoposts having various shapes are arranged even if they are shifted. For example, as shown in Fig. 32, rectangular nanoposts NP1 and NP2 having different sizes are stacked in two stages and shifted relative to each other. Also, 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 shifted relative to each other in each region of the color separation lens array.

[0186] 34 and 35 are cross-sectional views showing various cross-sectional shapes of nanoposts used in color separation lens arrays according to other embodiments. As shown in FIG. 34 and FIG. 35, an inclined surface may be formed on the side of the nanopost. For example, in the color separation lens array 250 shown 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. Thus, the nanoposts of the color separation lens array 250 have a trapezoidal cross section in which the top surface is larger than the bottom surface. Also, in the color separation lens array 260 shown in FIG. 35, an inclined surface is 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. Thus, the nanoposts of the color separation lens array 260 have a trapezoidal cross section in which the bottom surface is larger than the top surface.

[0187] The inclinations of the inclined surfaces of the nanoposts arranged in the first, second, third and fourth regions of the color separation lens arrays 250 and 260 may be different from each other. Also, the inclinations of the inclined surfaces of the nanoposts located in correspondence with the center of the image sensor may be different from the inclinations of the inclined surfaces of the nanoposts located in correspondence with the periphery of the image sensor.

[0188] FIG. 36 is a cross-sectional view showing a schematic structure of a pixel array according to another embodiment.

[0189] 36, the pixel array 1100d of the image sensor may include a first color separation lens array 280 and a second color separation lens array 290 having different nanopost arrangements. The second color separation lens array 290 is also 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 respect to 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 of the nanoposts of the first color separation lens array 280.

[0190] The arrangement of the nanoposts of the first color separation lens array 280 and the second color separation lens array 290 is determined taking into consideration the chief ray angle of light incident on the image sensor. For example, the arrangement of the nanoposts of the first color separation lens array 280 and the second color separation lens array 290 can be designed so that light that passes through the second color separation lens array 290 and the first color separation lens array 280 in succession and enters the sensor substrate 110 is efficiently color-separated and focused regardless of the incident angle.

[0191] As described above, the color separation lens array in which the sub-wavelength nanoposts are arranged in a predetermined order can increase the color separation efficiency, and the performance of the image sensor using the color separation lens array can be improved. The specific forms described are merely illustrative, and various modifications and combinations thereof are possible. For example, the visible light wavelength band has been exemplified, but the invention is not limited thereto, and other wavelength bands can be separated according to the nanopost arrangement order. In addition, the number of nanoposts provided in each of the multiple regions of the nanopost array can be changed in various ways. The pixel arrangement of the image sensor has been described using a Bayer pattern as an example, but the invention is not limited thereto, and for example, an arrangement in which red pixels, green pixels, and blue pixels are repeated in one direction is also possible, or an arrangement in the CYGM type shown in FIG. 2B or an arrangement in the RGBW type shown in FIG. 2C is also possible. In addition, the color separation lens array can 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 can adopt a region division appropriate for such a pixel arrangement, and select a nanopost arrangement order for each region.

[0192] Although the above description has been given of a color separation lens array formed through an arrangement of nanoposts formed in a definable shape, the color separation lens array can also be formed by various other free patterns that cannot be defined. For example, FIG. 37 is a conceptual diagram showing the schematic structure and operation of a color separation lens array according to another embodiment.

[0193] 37, the unit pattern array of the color separation lens array 330 may include a first region 331 to a fourth region 334 having first to fourth microstructures that are separated from each other. For example, the first region 331 may have a first pattern, the second region 332 may have a second pattern patterned in a different shape from the first pattern, the third region 333 may have a third pattern patterned in a different shape from the first and second patterns, and the fourth region 334 may have a fourth pattern patterned in a different shape from the first to third patterns.

[0194] The first region 331 to the fourth region 334 may be arranged on the same plane in a 2×2 pattern, for example. Thus, the first region 331 and the second region 332 are arranged adjacent to each other along a first direction, and the third region 333 and the fourth region 334 are also arranged adjacent to each other along the first direction. The first region 331 and the third region 333 are arranged adjacent to each other along a second direction perpendicular to the first direction, and the third region 333 and the fourth region 334 are also arranged adjacent to each other along the second direction. The first region 331 and the fourth region 334 are arranged along a diagonal direction, and the second region 332 and the third region 333 are arranged along the other diagonal direction.

[0195] According to an embodiment, the first to fourth patterns may be determined such that, among the incident light beams incident on the color separation lens array 330, the light beam λ1 having the first wavelength is focused on the first target region R1 facing the first region 331 along the vertical direction, the light beam λ2 having the second wavelength is focused on the second target region R2 facing the second region 332 along the vertical direction, the light beam λ3 having the third wavelength is focused on the third target region R3 facing the third region 333 along the vertical direction, and the light beam λ4 having the fourth wavelength is focused on the fourth target region R4 facing the fourth region 334 along the vertical direction. The specific patterns 1 to 4 of the first region 331 to the fourth region 334 may be variously designed according to the pixel arrangement and color characteristics of the image sensor to which the color separation lens array 330 is applied.

[0196] 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 are also arranged to face the green pixel G, the second region 332 is also arranged to face the blue pixel B, and the third region 333 is also arranged to face the red pixel R. The first wavelength light λ1 and the fourth wavelength light λ4 are also green light, the second wavelength light λ2 is also blue light, and the third wavelength light λ3 is also red light.

[0197] 38 is a plan view showing an example of a unit pattern array of a color separation lens array that is also applied to a Bayer pattern type image sensor. Referring to FIG. 38, a first region 331 facing a green pixel G includes a first dielectric 331a forming a first pattern and a second dielectric 331b filled between the first dielectric 331a. A second region 332 facing a blue pixel B includes a first dielectric 332a forming a second pattern and a second dielectric 332b filled between the first dielectric 332a, a third region 333 facing a red pixel R includes a first dielectric 333a forming a third pattern and a second dielectric 333b filled between the first dielectric 333a, and a fourth region 334 facing a green pixel G includes a first dielectric 334a forming a fourth pattern and a second dielectric 334b ​​filled between the first dielectric 334a.

[0198] The first region 331 and the second region 332 both face green pixels and have the same shape, but the rotation direction 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. Such a difference is also determined by the arrangement of adjacent pixels. In the case of FIG. 38, blue pixels B are arranged on the left and right of the green pixel G facing the first region 331, and red pixels R are arranged on the left and right of the green pixel G facing the fourth region 334, so that patterns that are the same but arranged in different rotation directions may be formed.

[0199] The first dielectrics 331a, 332a, 333a, and 334a may all be made of the same material, and the second dielectrics 331b, 332b, 333b, and 334b ​​may all be made of the same material. For example, the first dielectrics 331a, 332a, 333a, and 334a may be made of TiO 2 , GaN, SiN 3 , ZnS, ZnSe, Si 3 N 4 As described above, the second dielectrics 331b, 332b, 333b, and 334b ​​are made of a dielectric material having a high refractive index and a low absorption rate in the visible light band. 2Alternatively, the second dielectrics 331b, 332b, 333b, and 334b ​​may be made of a dielectric material that has a low refractive index and a low absorption rate in the visible light band, such as silanol-based glass (SOG). 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 easily formed by etching the first dielectrics 331a, 332a, 333a, and 334a.

[0200] FIG. 39 is an exemplary cross-sectional view showing a vertical cross-section of the unit pattern array shown in FIG. 38 cut along line A-A' (X direction), and FIG. 40 is an exemplary cross-sectional view showing a vertical cross-section of the unit pattern array shown in FIG. 38 cut along line B-B' (Y direction).

[0201] 39 and 40, the first dielectrics 331a, 332a, 333a, and 334a and the second dielectrics 331b, 332b, 333b, and 334b ​​may extend parallel to the vertical direction. The shapes of the vertical cross sections shown in Fig. 39 and 40 are merely examples, and the shapes of the vertical cross sections of the first region 331 to the fourth region 334 may differ depending on the positions of the A-A' line and the B-B' line. For example, the shape of the vertical cross section shown in Fig. 39 changes when the A-A' line moves along the Y direction, and the shape of the vertical cross section shown in Fig. 40 changes when the B-B' line moves along the X direction. Regardless of such a change in the vertical cross-sectional shape, in all vertical cross-sections of the first region 331 to the fourth region 334, the first dielectrics 331a, 332a, 333a, and 334a and the second dielectrics 331b, 332b, 333b, and 334b ​​may exist together.

[0202] Fig. 41 is a plan view showing an example of an arrangement of a color separation lens array including a plurality of unit pattern arrays shown in Fig. 38. As shown in Fig. 41, the color separation lens array 330 may have a shape in which the 2 x 2 unit pattern arrays shown in Fig. 38 are repeatedly arranged two-dimensionally.

[0203] In the color separation lens array 330 applied to the image sensor of the Bayer pattern type, the first to fourth patterns of the first to fourth regions 331 to 334 may have a predetermined rule. For example, FIG. 42A exemplarily illustrates the pattern of the first region 331 in the unit pattern array illustrated in FIG. 38, and FIG. 42B exemplarily illustrates the corresponding pixels of the image sensor and its surrounding pixels. Referring to FIG. 42B, a blue pixel B is arranged in the left-right direction of the green pixel G corresponding to the first region 331, and a red pixel R is arranged in the up-down direction. A green pixel corresponding to the fourth region 334 is arranged in the diagonal direction of the green pixel G corresponding to the first region 331, and is not shown in FIG. 42B. Therefore, in order to obtain the same optical effect as when the blue light of the transmitted light transmitted through the first region 331 travels in the left-right direction of the first region 331 and the red light travels in the up-down direction of the first region 331, the first pattern of the first region 331 is also two-fold symmetric. For example, as shown in FIG. 42A, the first pattern of the first region 331 is symmetrical about a first axis I along the Y direction and also symmetrical about a second axis II along the X direction.

[0204] FIG. 43A exemplarily illustrates the shape of the second region 332 in the unit pattern array illustrated in FIG. 38, and FIG. 43B exemplarily illustrates the corresponding pixel and its surrounding pixels of the image sensor. Referring to FIG. 43B, green pixels G are arranged in the left-right and up-down directions of the blue pixel B corresponding to the second region 332. And red pixels R are arranged in the two intersecting diagonal directions. Therefore, in order to obtain the same optical effect as when the green light of the transmitted light transmitted through the second region 332 advances in the left-right and up-down directions of the second region 332 and the red light advances in the diagonal direction of the second region 332, the second pattern of the second region 332 is also four-fold symmetric. For example, as illustrated in FIG. 43A, the second pattern of the second region 332 is symmetric about a first axis I along the Y direction, a second axis II along the X direction, and a third axis III and a fourth axis IV along the diagonal directions.

[0205] FIG. 44A exemplarily illustrates the shape of the third region 333 in the unit pattern array illustrated in FIG. 38, and FIG. 44B exemplarily illustrates the corresponding pixel and its peripheral pixels of the image sensor. Referring to FIG. 44B, green pixels G are arranged in the left-right and up-down directions of the red pixel R corresponding to the third region 333. And blue pixels B are arranged in the two intersecting diagonal directions. Therefore, in order to obtain the same optical effect as when the green light of the transmitted light transmitted through the third region 333 advances in the left-right and up-down directions of the third region 333 and the blue light advances in the diagonal direction of the third region 333, the third pattern of the third region 333 is also 4-fold symmetric. For example, as illustrated in FIG. 44A, the third pattern of the third region 333 is symmetric about a first axis I along the Y direction, a second axis II along the X direction, and a third axis III and a fourth axis IV along the diagonal directions.

[0206] FIG. 45A exemplarily illustrates the shape of the fourth region 334 in the unit pattern array illustrated in FIG. 38, and FIG. 45B exemplarily illustrates the corresponding pixel of the image sensor and its surrounding pixels. Referring to FIG. 45B, a red pixel R is arranged in the left-right direction of a green pixel G corresponding to the fourth region 334, and a blue pixel B is arranged in the up-down direction. A green pixel corresponding to the first region 331 is arranged in the diagonal direction and is not shown in FIG. 45B. Therefore, in order to obtain the same optical effect as when the red light of the transmitted light transmitted through the fourth region 334 travels in the left-right direction of the fourth region 334 and the blue light travels in the up-down direction of the fourth region 334, the fourth pattern of the fourth region 334 is also two-fold symmetric. For example, as illustrated in FIG. 45A, the fourth pattern of the fourth region 334 is symmetric with respect to a first axis I along the Y direction and a second axis II along the X direction. In addition, the pixel arrangement shown in Fig. 45B is rotated 90° with respect to the pixel arrangement shown in Fig. 42B. Therefore, the fourth pattern of the fourth region 334 may have the same shape as the first pattern of the first region 331 rotated 90°.

[0207] As another rule of the first to fourth patterns of the first region 331 to the fourth region 334 in the color separation lens array 330 applied to the Bayer pattern type image sensor, the first to fourth patterns of the first region 331 to the fourth region 334 may be designed so that blue light, green light, and red light transmitted through the color separation lens array 330 have a predetermined target phase distribution. For example, the first to fourth patterns of the first region 331 to the fourth region 334 may be determined so that the blue light transmitted through the color separation lens array 330 forms a phase in which it is focused at the position of the blue pixel B corresponding to the second region 332, and does not proceed to the positions corresponding to the first region 331 and the fourth region 334 adjacent to the second region 332.

[0208] In addition, patterns 1 to 4 of the first region 331 to the fourth region 334 can be determined so that the green light passing through the color separation lens array 330 forms a phase in which it is focused at the position of the green pixel G corresponding to the first region 331 and the fourth region 334, and does not proceed to the positions corresponding to the second region 332 and the third region 333 adjacent to the first region 331 and the fourth region 334.

[0209] In addition, patterns 1 to 4 of the first region 331 to the fourth region 334 can be determined so that the red light passing through the color separation lens array 330 forms a phase in which it is focused on the red pixel R corresponding to the third region 333, and does not proceed to positions corresponding to the first region 331 and the fourth region 334 adjacent to the third region 333.

[0210] The target phase distribution realized by the color separation lens array 330 is the same as that described for the color separation lens array 130, and therefore a detailed description thereof will be omitted. Due to the first to fourth patterns of the first to fourth regions 331 to 334, the color separation lens array 330 can perform the same functions as those described in Figures 6A to 6D, 7A to 7D, and 8A to 8D.

[0211] The pattern of the color separation lens array 330 satisfying the above-mentioned phase distribution can be designed automatically through various computer simulations. For example, the patterns of the first region 331 to the fourth region 334 can be optimized using a nature-inspired algorithm such as a genetic algorithm, a particle swarm optimization algorithm, or an ant colony optimization algorithm, or through a paradoxical method based on an adjoint optimization algorithm.

[0212] In order to design the color separation lens array 330, the first to fourth patterns of the first region 331 to the fourth region 334 may be optimized while evaluating the performance of the candidate color separation lens arrays using evaluation factors such as color separation spectrum, light efficiency, and signal-to-noise ratio. For example, after determining a target value for each evaluation factor in advance, the first to fourth patterns of the first region 331 to the fourth region 334 may be optimized by minimizing the sum of the differences between the target values ​​and the evaluation factors. Alternatively, the performance may be indexed for each evaluation factor, and the first to fourth patterns of the first region 331 to the fourth region 334 may be optimized so that a value indicating the performance is maximized.

[0213] The color separation lens array 330 shown in Fig. 38 is only one example, and various types of color separation lens arrays 330 can be obtained through the above-mentioned optimization design depending on the size and thickness of the first region 331 to the fourth region 334 of the color separation lens array 330, the color characteristics and pixel pitch of the image sensor to which the color separation lens array 330 is applied, the distance between the color separation lens array 330 and the image sensor, the incidence angle of the incident light, etc. For example, Fig. 46 is a plan view illustrating an example of a shape of a unit pattern array of a color separation lens array according to another embodiment that is also applicable to a Bayer pattern type image sensor, and Fig. 47 is a plan view illustrating an example of a shape of a unit pattern array of a color separation lens array according to yet another embodiment that is also applicable to a Bayer pattern type image sensor.

[0214] Each of the first to fourth regions 331 to 334 shown in Fig. 38 is optimized in a binary form digitized into a 14x14 rectangular array, and each of the first to fourth regions 331 to 334 shown in Fig. 46 is optimized in a binary form digitized into a 16x16 rectangular array. Therefore, the unit pattern array of the color separation lens array 330 shown in Fig. 38 has a form formed by a 28x28 rectangular array, and the unit pattern array of the color separation lens shown in Fig. 46 has a form formed by a 32x32 rectangular array. In this case, the form of the vertical cross section of the first to fourth regions 331 to 334 shown in Figs. 39 and 40 changes discontinuously as the A-A' line moves along the Y direction or the B-B' line moves along the X direction.

[0215] In contrast, each of the first region 331 to the fourth region 334 shown in Fig. 47 is also optimized for a non-digitized continuous curve shape. In this case, the shape of the vertical cross section of the first region 331 to the fourth region 334 shown in Fig. 39 and Fig. 40 changes continuously as the A-A' line moves along the Y direction or the B-B' line moves along the X direction.

[0216] 48A and 48B are schematic cross-sectional views showing different cross sections of a pixel array of an image sensor employing a color separation lens array. Referring to Figs. 48A and 48B, a pixel array 1100e of the image sensor may include a sensor substrate 110, a spacer layer 120, and a color separation lens array 330. A first region 331 of the color separation lens array 330 is disposed corresponding to a first photosensitive cell 111 of the sensor substrate 110, and a second region 332 of the color separation lens array 330 is disposed corresponding to a second photosensitive cell 112 of the sensor substrate 110. In addition, the second region 332 of the color separation lens array 330 is disposed corresponding to the second photosensitive cell 112 of the sensor substrate 110, and a fourth region 334 of the color separation lens array 330 is disposed corresponding to a fourth photosensitive cell 114 of the sensor substrate 110. 48A and 48B , a color filter may further be disposed between the sensor substrate 110 and the spacer layer 120. As described above, the thickness of the spacer layer is determined by a predetermined propagation distance requirement for the light beams with different wavelengths separated by the color separation lens array 330 to be focused on the corresponding photosensitive cells.

[0217] The specific patterns of the color separation lens array 330 described above are merely examples, and various modifications thereof are possible. For example, it is possible to separate wavelength bands other than visible light by using other pattern shapes of the first region 331 to the fourth region 334 of the color separation lens array 330. In addition, the number of color separation patterns constituting the unit pattern array of the color separation lens array 330 may be variously changed depending on the application of the color separation lens array 330. Although the pixel arrangement of the image sensor has been described using the Bayer pattern as an example, it is not limited thereto, and may be applied to the pixel arrangements shown in FIGS. 2B and 2C. A pattern suitable for such a pixel arrangement may be determined by selecting the region of the color separation lens array 330 and performing the above-mentioned optimization method for each region.

[0218] FIG. 49 is a plan view illustrating a color separation lens array according to another embodiment. Referring to FIG. 49, the color separation lens array 340 may include a plurality of unit pattern arrays arranged two-dimensionally, which are indicated by thick lines. Each unit pattern array is also arranged in a 2×2 dimensional form including a first region 341, a second region 342, a third region 343, and a fourth region 344. When looking at the overall configuration of the color separation lens array 340, the first region 341 and the second region 342 are alternately arranged in the horizontal direction in one row, and the third region 343 and the fourth region 344 are alternately arranged in the horizontal direction in another row. 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 alternately arranged in the vertical direction in another column.

[0219] In addition, the color separation lens array 340 may further include a plurality of first regions 341 to a fourth region 344 that do not belong to any unit pattern array. The first regions 341 to a fourth region 344 that do not belong to any unit pattern array are also 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 may be additionally arranged on the left edge of the color separation lens array 340, a plurality of first regions 341 and a plurality of third regions 343 constituting one column may be additionally arranged on the right edge, a plurality of third regions 343 and a plurality of fourth regions 344 constituting one row may be additionally arranged on the upper edge, and a plurality of first regions 341 and a plurality of second regions 342 constituting one row may be additionally arranged on the lower edge.

[0220] Fig. 50 is a vertical cross-sectional view of the color separation lens array 340 shown in Fig. 49 taken along line CC'. Referring to Fig. 50, the color separation lens array 340 may include a plurality of first regions 341 and a plurality of second regions 342 that are arranged to protrude in the horizontal direction from an edge of the sensor substrate 110 and do not face any photosensitive cells of the sensor substrate 110 in the vertical direction. Although none of them are shown in Fig. 50, the plurality of first regions 341 to fourth regions 344 that do not belong to any unit pattern array in Fig. 50 are all arranged to protrude in the horizontal direction from an edge of the sensor substrate 110 and do not face any photosensitive cells in the vertical direction.

[0221] As described with reference to FIGS. 6A to 6D, 7A to 7D, and 8A to 8D, the photosensitive cells are provided with light not only from the region of the color separation lens array 340 that corresponds to the vertical direction, but also from a number of other regions around the region. Therefore, if the first to fourth regions 341 to 344 were not added along the edge of the color separation lens array 340, the amount of light incident on the photosensitive cells arranged along the edge of the sensor substrate 110 would be reduced, and the color purity would also be reduced. By additionally arranging the first to fourth regions 341 to 344 along the edge of the color separation lens array 340, light can be provided to the photosensitive cells arranged along the edge of the sensor substrate 110 in the same manner as the photosensitive cells arranged inside the sensor substrate 110. Such an embodiment illustrated in FIGS. 49 and 50 may also be applied to the color separation lens array including the above-mentioned array of nanoposts.

[0222] Meanwhile, when applied to the camera 2000 shown in FIG. 22, the shape of the plurality of unit pattern arrays of the color separation lens array can be designed differently in consideration of the chief ray angle of the incident light. For example, FIG. 51 is a plan view illustrating an example of the arrangement of a plurality of unit pattern arrays of a color separation lens array according to another 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 patterns according to positions on the image sensor. For example, in consideration of the chief ray angle of the incident light incident on the positions on the image sensor where the unit pattern arrays 350a to 350i are arranged, the patterns of the first to fourth regions of each of the unit pattern arrays 350a to 350i can be determined through the above-mentioned optimization algorithm. If the chief ray angle of light incident on the center of the image sensor is 0° and the chief ray angle of the incident light increases toward the edge of the image sensor, the patterns of the first to fourth regions of unit pattern arrays 350a to 350i may gradually change from unit pattern array 350e arranged in the center of the image sensor toward unit pattern arrays 350a, 350b, 350c, 350d, 350f, 350g, 350h, and 350i arranged at the edges of the image sensor.

[0223] In addition, two different color separation lens arrays may be stacked in a two-layer structure to obtain a constant color separation efficiency regardless of the change in the chief ray angle of the incident light which 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 embodiment. Referring to FIG. 52, the pixel array 1100f of the image sensor may include a first color separation lens array 360 disposed on the spacer layer 120, and a second color separation lens array 370 disposed on the first color separation lens array 360.

[0224] The first color separation lens array 360 may include a first region 361 arranged in the vertical direction to face the first photosensitive cells 111, and a second region 362 arranged in the vertical direction to face the second photosensitive cells 112. 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 other cross-sectional positions. The second color separation lens array 370 may include a first region 371 arranged in the vertical direction to face the first photosensitive cells 111, and a second region 372 arranged in the vertical direction to face the second photosensitive cells 112. Therefore, the first region 361 and the second region 362 of the first color separation lens array 360 are also arranged in the vertical direction to face the first region 371 and the second region 372 of the second color separation lens array 370, respectively. Moreover, the second color separation lens array 370 may also further include a third region and a fourth region.

[0225] The first region 361 and the second region 362 of the first color separation lens array 360 may have patterns different from each other, and the first region 371 and the second region 372 of the second color separation lens array 370 may also have patterns different from each other. In addition, the first region 361 of the first color separation lens array 360 may have a pattern different from the first region 371 and the second region 372 of the second color separation lens array 370, and the second region 362 of the first color separation lens array 360 may have a pattern different from the first region 371 and the second region 372 of the second color separation lens array 370.

[0226] In such a structure, the patterns of the second color separation lens array 370 and the first color separation lens array 360 can be designed so that the light that passes through the second color separation lens array 370 and the first color separation lens array 360 in succession and enters the sensor substrate 110 is efficiently color-separated regardless of the incident angle. For example, the second color separation lens array 370 has a different shape depending on the position on the image sensor, and the incident light traveling direction can be changed to be approximately parallel to the surface normal of the first color separation lens array 360. In that case, the pattern of the first color separation lens array 360 is also constant regardless of the position on the image sensor. Or, the pattern of the first color separation lens array 360 and the pattern of the second color separation lens array 370 are shifted from each other along the light traveling direction.

[0227] The image sensor according to the above embodiment can provide a sufficient amount of light to the pixel even if the pixel size is small because there is almost no light loss due to the color filter. Therefore, it is possible to fabricate an ultra-high resolution micro-high sensitivity image sensor having hundreds of millions of pixels. Such an ultra-high resolution micro-high sensitivity image sensor can also be used in various high performance optical devices or high performance electronic devices. For example, such electronic devices can be, but are not limited to, smartphones, mobile phones, mobile phones, PDAs (personal digital assistants), laptops, PCs, various portable devices, home appliances, security cameras, medical cameras, automobiles, Internet of Things (IoT), and other mobile or non-mobile computing devices.

[0228] 53 is a block diagram illustrating an electronic device including an image sensor according to an embodiment. 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 related to an external object under the control of the processor 2200 and provides the image information to the processor 2200. The processor 2200 stores the image information provided from the image sensor 1000 in the memory 2300 via the bus 2500, and outputs the image information stored in the memory 2300 to the display 2400 to display it to a user. The processor 2200 can also perform various image processes on the image information provided from the image sensor 1000.

[0229] 54 to 64 show various examples of electronic devices to which an image sensor according to an embodiment is applied.

[0230] The image sensor according to an embodiment of the present invention may be applied to various multimedia devices having a video capture function. For example, the image sensor may be applied to a camera 2000 shown in Fig. 54. The camera 2000 may be a digital camera or a digital camcorder.

[0231] Referring to FIG. 55, the camera 2000 may include an imaging unit 2100, an image sensor 1000, and a processor 2200.

[0232] The imaging unit 2100 focuses light reflected from the object OBJ to form an optical image. The imaging unit 2100 may include an objective lens 2010, a lens driver 2120, an aperture 2130, and an aperture driver 2140. Although only one lens is shown representatively in FIG. 55 for convenience, the objective lens 2010 may actually include a plurality of lenses having different sizes and shapes. The lens driver 2120 may communicate information related to 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 2120 may move the objective lens 2010 to adjust the distance between the objective lens 2010 and the object OBJ, or adjust the position of each lens in the objective lens 2010. The lens driver 2120 may drive the objective lens 2010 to adjust the focus on the object OBJ. Such a camera 2000 may be equipped with an autofocus function.

[0233] The aperture driver 2140 can communicate information related to the amount of light with the processor 2200, and can adjust the aperture 2130 according to a control signal provided from the processor 2200. For example, the aperture driver 2140 can increase or decrease the aperture of the aperture 2130 and adjust the opening time of the aperture 2130 according to the amount of light entering the camera 2000 through the objective lens 2010.

[0234] The image sensor 1000 can generate an electrical image signal based on the intensity of the incident light. The image sensor 1000 may include a pixel array 1100, a timing controller (T / C) 1010, and an output circuit 1030. Although not shown in FIG. 55, the image sensor 1000 may further include a row decoder as shown in FIG. 1. The light transmitted through the objective lens 2010 and the aperture 2130 can form an object OBJ image on the light receiving surface of the pixel array 1100. The pixel array 1100 may be a CCD or CMOS that converts an optical signal into an electrical signal. The pixel array 1100 may include additional pixels for performing an AF function or a distance measurement function. The pixel array 1100 may also include the above-mentioned color separation lens array.

[0235] 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 control signals for the operation of each component to the lens driver 2120, the aperture driver 2140, the timing controller 1010, etc.

[0236] The image sensor according to an embodiment may be applied to a mobile phone or smartphone 3000 shown in FIG. 56, a tablet or smart tablet 3100 shown in FIG. 57, a laptop computer 3200 shown in FIG. 58, and a television or smart television 3300 shown in FIG. 59. For example, the smartphone 3000 or the smart tablet 3100 may include a plurality of high-resolution cameras each equipped with a high-resolution image sensor. The high-resolution cameras may be used to extract depth information of an object in an image, adjust out-focusing of the image, or automatically identify an object in an image.

[0237] The image sensor is also 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. For example, the smart refrigerator 3400 can automatically recognize food and drink in the refrigerator using the image sensor and can notify a user via a smartphone of the presence or absence of a specific food and drink and the type of food and drink that has been taken in and out. The security camera 3500 can provide ultra-high resolution images and can recognize objects or people in images even in dark environments using high sensitivity. The robot 3600 can be deployed in disaster sites or industrial sites where people cannot directly approach and can provide high resolution images. The medical camera 3700 can provide high resolution images for diagnosis or surgery and can dynamically adjust the field of view.

[0238] The image sensor is also applied to a vehicle 3800 as shown in Fig. 64. The vehicle 3800 includes a plurality of vehicle cameras 3810, 3820, 3830, and 3840 arranged at various positions, and each of the vehicle cameras 3810, 3820, 3830, and 3840 may include an image sensor according to an embodiment. The vehicle 3800 can provide a driver with various information related to the inside or surroundings of the vehicle 3800 by using the plurality of vehicle cameras 3810, 3820, 3830, and 3840, and can automatically recognize objects or people in the image and provide information required for autonomous driving.

[0239] The image sensor having the above-mentioned color separation lens array and the electronic device including the same have been described with reference to the embodiments shown in the drawings, but they are merely exemplary, and a person skilled in the art will understand that various modifications and other equivalent embodiments are possible therefrom. Therefore, the disclosed embodiments should be considered from an illustrative perspective, not a restrictive one. The scope of the claims is set forth in the claims, not the above description, and all differences within the scope of the claims should be interpreted as being within the scope of the claims. [Explanation of symbols]

[0240] 105 Color Filter 110 Sensor board 111,112,113,114 Photosensitive cell 120 Spacer layer 121 Dielectric layer 130,140,150,160,170 Color separation lens array 131,141,151,161,171 1st area 132,142,152,162,172 2nd area 133,143,153,163,173 Third area 134,144,154,164,174 4th area 1000 Image Sensor 1010 Timing Controller 1020 Row Decoder 1030 Output circuit 1100 pixel array

Claims

1. An image sensor comprising: a sensor substrate including a plurality of first photosensitive cells and a plurality of second photosensitive cells that detect light; a color separation lens array including a plurality of first regions each corresponding to the first photosensitive cells and having a first microstructure, and a plurality of second regions each corresponding to the second photosensitive cells and having a second microstructure different from the first microstructure, the first microstructure and the second microstructure split light having a first wavelength and light having a second wavelength, which are different from each other, from the incident light incident on the color separation lens array into light having a first wavelength and light having a second wavelength, in different directions, and form phase distributions at positions where the light passes through the first region and the second region and is focused on the first photosensitive cell and the second photosensitive cell, respectively; at a central portion of the color separation lens array, the positions of the first regions and the second regions coincide with the positions of the first photosensitive cells and the second photosensitive cells corresponding thereto, respectively, and at a peripheral portion of the color separation lens array, the positions of the first regions and the second regions are shifted toward the central portion of the color separation lens array with respect to the positions of the first photosensitive cells and the second photosensitive cells corresponding thereto, respectively; the first and second microstructures in the first and second regions include nanoposts with first nanoposts and second nanoposts stacked on the first nanoposts; An image sensor, wherein at a periphery of the image sensor, the second nanoposts are shifted toward a center of the image sensor relative to the first nanoposts.

2. An image sensor as described in claim 1, wherein, at the center of the image sensor, the position of the second nanopost coincides with the position of the first nanopost.

3. The image sensor of claim 1 or 2, wherein the degree to which the second nanoposts are shifted relative to the first nanoposts in the periphery of the image sensor increases with distance from the center of the image sensor.

4. An image sensor comprising: a sensor substrate including a plurality of first photosensitive cells and a plurality of second photosensitive cells that detect light; a color separation lens array including a plurality of first regions each corresponding to the first photosensitive cells and having a first microstructure, and a plurality of second regions each corresponding to the second photosensitive cells and having a second microstructure different from the first microstructure, the first microstructure and the second microstructure split light having a first wavelength and light having a second wavelength, which are different from each other, from the incident light incident on the color separation lens array into light having a first wavelength and light having a second wavelength, in different directions, and form phase distributions at positions where the light passes through the first region and the second region and is focused on the first photosensitive cell and the second photosensitive cell, respectively; at a central portion of the color separation lens array, the positions of the first regions and the second regions coincide with the positions of the first photosensitive cells and the second photosensitive cells corresponding thereto, respectively, and at a peripheral portion of the color separation lens array, the positions of the first regions and the second regions are shifted toward the central portion of the color separation lens array with respect to the positions of the first photosensitive cells and the second photosensitive cells corresponding thereto, respectively; the first and second microstructures in the first and second regions include nanoposts, the nanoposts comprising a first nanopost, a second nanopost stacked on the first nanopost, and a third nanopost stacked on the second nanopost; An image sensor, wherein, at a periphery of the image sensor, the second nanoposts are shifted relative to the first nanoposts toward a center of the image sensor, and the third nanoposts are shifted relative to the second nanoposts toward a center of the image sensor.

5. An image sensor as described in claim 4, wherein, at the center of the image sensor, the position of the second nanopost and the position of the third nanopost coincide with the position of the first nanopost.

6. An image sensor comprising: a sensor substrate including a plurality of first photosensitive cells and a plurality of second photosensitive cells that detect light; a color separation lens array including a plurality of first regions each corresponding to the first photosensitive cells and having a first microstructure, and a plurality of second regions each corresponding to the second photosensitive cells and having a second microstructure different from the first microstructure, the first microstructure and the second microstructure split light having a first wavelength and light having a second wavelength, which are different from each other, from the incident light incident on the color separation lens array into light having a first wavelength and light having a second wavelength, in different directions, and form phase distributions at positions where the light passes through the first region and the second region and is focused on the first photosensitive cell and the second photosensitive cell, respectively; at a central portion of the color separation lens array, the positions of the first regions and the second regions coincide with the positions of the first photosensitive cells and the second photosensitive cells corresponding thereto, respectively, and at a peripheral portion of the color separation lens array, the positions of the first regions and the second regions are shifted toward the central portion of the color separation lens array with respect to the positions of the first photosensitive cells and the second photosensitive cells corresponding thereto, respectively; An image sensor, wherein the line width of nanoposts arranged in any one of the first region, second region, third region, and fourth region in the peripheral portion of the image sensor is wider than the line width of nanoposts arranged at the same position in the same region in the center of the image sensor.

7. At the periphery of the image sensor, the nanoposts have a line width of w, and at the center of the image sensor, the nanoposts have a line width of w ０ When [0010] Satisfied, 7. The image sensor of claim 6, wherein CRA is the angle of incidence of light incident on the color separation lens array.

8. 8. The image sensor of claim 6 or 7, wherein the line width of the nanoposts at the outermost edges of the image sensor is 2.5% to 6.5% greater than the line width of the nanoposts at a center of the image sensor.

9. the sensor substrate further includes a plurality of third photo-sensing cells and a plurality of fourth photo-sensing cells that sense light, the color separation lens array includes a plurality of third regions corresponding to the third photosensitive cells, respectively, and having a third microstructure different from the first microstructure and the second microstructure; and a plurality of fourth regions corresponding to the fourth photosensitive cells, respectively, and having a fourth microstructure different from the first microstructure to the third microstructure; 9. The image sensor according to claim 1, wherein each of the first, second, third and fourth regions is arranged along four quadrants, respectively.

10. the positions of the first region, the second region, the third region and the fourth region of the color separation lens array coincide with the positions of the first photosensitive cell, the second photosensitive cell, the third photosensitive cell and the fourth photosensitive cell, respectively, at a central portion of the image sensor; 10. The image sensor of claim 9, wherein, in the peripheral portion of the image sensor, the first region, the second region, the third region and the fourth region of the color separation lens array are shifted toward the central portion of the image sensor relative to the first photosensitive cells, the second photosensitive cells, the third photosensitive cells and the fourth photosensitive cells corresponding thereto, respectively.

11. 11. The image sensor of claim 10, wherein the degree to which the first, second, third and fourth regions of the color separation lens array are shifted relative to the corresponding first, second, third and fourth photosensitive cells in the peripheral portion of the image sensor increases as the region gets farther away from the central portion of the image sensor.

12. 12. The image sensor of claim 9, wherein the first to fourth microstructures form a phase distribution at a position passing through the first to fourth regions, in which light of different first to third wavelengths among incident light entering the color separation lens array is branched into different directions, and the light of the first wavelength is focused on the first photosensitive cell and the fourth photosensitive cell, the light of the second wavelength is focused on the second photosensitive cell, and the light of the third wavelength is focused on the third photosensitive cell.

13. 13. The image sensor of claim 12, wherein the first wavelength is green light, the second wavelength is blue light, and the third wavelength is red light.

14. The first microstructure to the fourth microstructure are the light having a first wavelength forms a phase distribution of 2Nπ at the central portion of the first photosensitive cell and the central portion of the fourth photosensitive cell and forms a phase distribution of (2N−1)π at the central portion of the second photosensitive cell and the central portion of the third photosensitive cell, immediately after passing through the color separation lens array; the light of the second wavelength has a phase distribution of (2M−1)π at the center of the first photosensitive cell and at the center of the fourth photosensitive cell just after passing through the color separation lens array, a phase distribution of 2Mπ is formed at the center of the second photosensitive cell, and a phase distribution of greater than (2M−2)π and smaller than (2M−1)π is formed at the center of the third photosensitive cell, 14. The image sensor according to claim 12, wherein, immediately after passing through the color separation lens array, the light of a third wavelength forms a phase distribution of (2L-1)π at the central portion of the first photosensitive cell and the central portion of the fourth photosensitive cell, a phase distribution of 2Lπ at the central portion of the third photosensitive cell, and a phase distribution larger than (2L-2)π and smaller than (2L-1)π at the central portion of the second photosensitive cell, and N, M, and L are integers larger than 0.

15. An image sensor as described in any one of claims 9 to 14, wherein the first microstructure to the fourth microstructure in the first region to the fourth region include a plurality of nanoposts, and at least one of the shape, size, and arrangement of the nanoposts in the first region to the fourth region are different from each other.

16. The image sensor has a pixel array structure in which a plurality of unit pixels including red pixels, green pixels, and blue pixels are repeatedly arranged, 16. The image sensor of claim 15, wherein the nanoposts provided in the first to fourth regions corresponding to green pixels have different distribution patterns along a first direction and a second direction perpendicular to the first direction.

17. 17. The image sensor of claim 16, wherein the nanoposts provided in the first to fourth regions corresponding to blue and red pixels have a symmetrical distribution pattern along the first and second directions.

18. 18. The image sensor of claim 1, wherein in the peripheral portion of the color separation lens array, the degree to which the first regions and the second regions are shifted relative to the corresponding first photosensitive cells and second photosensitive cells increases as the first regions and the second regions are shifted away from the central portion of the color separation lens array.

19. The distance s by which the first region and the second region are shifted with respect to the corresponding first photosensitive cell and the corresponding second photosensitive cell is given by: [0025] The image sensor according to any one of claims 1 to 18, wherein d is the shortest straight-line distance between the lower surface of the color separation lens array and the upper surface of the sensor substrate, and CRA' is the angle of incidence of light incident on the sensor substrate.

20. 20. The image sensor of claim 1, wherein the first microstructure and the second microstructure are configured so that, at a position immediately after passing through the color separation lens array, light of a first wavelength forms a phase distribution of 2Nπ at the center of the first photosensitive cell and a phase distribution of (2N-1)π at the center of the second photosensitive cell, where N is an integer greater than 0.

21. 21. The image sensor of claim 20, wherein the first microstructure and the second microstructure form a phase distribution of (2M-1)π at the center of the first photosensitive cell and a phase distribution of 2Mπ at the center of the second photosensitive cell at a position immediately after passing through the color separation lens array, where M is an integer greater than 0.

22. The image sensor according to any one of claims 1 to 21, further comprising a spacer layer disposed between the sensor substrate and the color separation lens array, forming a distance between the sensor substrate and the color separation lens array.

23. The theoretical thickness of the spacer layer is h ｔ and the pitch of each of the first photosensitive cells and the second photosensitive cells is p, the thickness h of the spacer layer is expressed as h ｔ -p≦h≦h ｔ -p, 23. The image sensor of claim 22, wherein the theoretical thickness of the spacer layer is a focal length of the color separation lens array at a central wavelength of a wavelength band of incident light that is color separated by the color separation lens array.

24. The refractive index of the spacer layer is n, and the center wavelength of the wavelength band of light that is color-separated by the color separation lens array is λ ０ Then, the theoretical thickness h of the spacer layer ｔ is expressed as follows: [0030] 24. The image sensor of claim 23, wherein:

25. 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; An image sensor as described in any one of claims 1 to 24, wherein the first microstructures and the second microstructures in the first and second regions of the first color separation lens array include a plurality of nanoposts, the first microstructures and the second microstructures in the first and second regions of the second color separation lens array include a plurality of nanoposts, and the arrangement pattern of the plurality of nanoposts in the first color separation lens array is different from the arrangement pattern of the plurality of nanoposts in the second color separation lens array.

26. an imaging unit that focuses light reflected from a subject to form an optical image; and an image sensor according to any one of claims 1 to 25, The image sensor is an electronic device that converts the optical image formed by the imaging unit into an electrical signal.

27. 27. The electronic device of claim 26, wherein the electronic device is a smart phone, a mobile phone, a personal digital assistant (PDA), a laptop or a personal computer (PC).

Images