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

Abstract

An image sensor includes: a sensor substrate including first and second photosensitive cells configured to sense light; and a dichroic lens array including a first region and a second region, wherein the first region faces the first photosensitive cell and includes a first nanopillar, and the second region faces the second photosensitive cell and includes a second nanopillar. The first and second nanopillars form a phase distribution at locations where light passes through the first and second regions. Due to the phase distribution, light having a first wavelength and light having a second wavelength, which are different from each other, of incident light incident on the dichroic lens array are branched in different directions, and the light having the first wavelength is focused on the first photosensitive cell, while the light having the second wavelength is focused on the second photosensitive cell.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of Korean Patent Application No. 10-2019-0132385 filed on October 23, 2019, Korean Patent Application No. 10-2019-0146210 filed on November 14, 2019, and Korean Patent Application No. 10-2020-0116333 filed on September 10, 2020, both filed in the Korean Intellectual Property Office, the disclosures of which are hereby incorporated by reference in their entirety. Technical Field

[0003] The present disclosure relates to an image sensor including a color separation lens array and an electronic device including the image sensor, and more particularly, to an image sensor including a color separation lens array capable of separating and converging incident light according to wavelength, and an electronic device including the image sensor. Background Art

[0004] Image sensors typically detect the color of incident light using color filters. However, because color filters absorb light of colors other than the color corresponding to the filter, light usage efficiency can decrease. For example, when using red, green, and blue (RGB) color filters, only one-third of the incident light passes through the RGB filters, while the remaining two-thirds is absorbed, resulting in a light usage efficiency of approximately 33%. Therefore, in color displays or color image sensors, most light loss occurs in the color filters. Summary of the Invention

[0005] One or more embodiments include an image sensor having improved light utilization efficiency by using a dichroic lens array in which incident light can be separated and condensed according to wavelengths.

[0006] One or more embodiments also include an electronic device including an image sensor.

[0007] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the embodiments presented herein.

[0008] According to one aspect of the present disclosure, an image sensor is provided, comprising: a sensor substrate comprising a first photosensitive unit and a second photosensitive unit configured to sense light; and a color separation lens array comprising a first area and a second area, wherein the first area faces the first photosensitive unit and comprises a first nanocolumn, and the second area faces the second photosensitive unit and comprises a second nanocolumn, wherein at least one of a first size, a first shape, or a first arrangement of the first nanocolumn is different from at least one of a second size, a second shape, or a second arrangement of the second nanocolumn, and wherein the first nanocolumn and the second nanocolumn form a phase distribution at a position where light passes through the first area and the second area, through which light with a first wavelength and light with a second wavelength that are different from each other in the incident light incident on the color separation lens array are branched to different directions, and the light with the first wavelength converges onto the first photosensitive unit, and the light with the second wavelength converges onto the second photosensitive unit.

[0009] For light of the first wavelength, the first nanocolumn and the second nanocolumn are formed at the position immediately after the light passes through the color separation lens array: a phase distribution of 2Nπ at the position corresponding to the center of the first photosensitive unit, and a phase distribution of (2N-1)π at the position corresponding to the center of the second photosensitive unit, where N is an integer greater than 0.

[0010] For light of the second wavelength, the first nanocolumn and the second nanocolumn are formed at the position immediately after the light passes through the color separation lens array: a phase distribution of (2M-1)π at the position corresponding to the center of the first photosensitive unit, and a phase distribution of 2Mπ at the position corresponding to the center of the second photosensitive unit, where M is an integer greater than 0.

[0011] The image sensor may further include: a spacer layer disposed between the sensor substrate and the color separation lens array.

[0012] The thickness of the spacer layer may correspond to the focal length of the dichroic lens array relative to the center wavelength of the wavelength band of incident light to be separated by the dichroic lens array.

[0013] According to example embodiments, when the theoretical thickness of the spacer layer is h t When the spacing between each photosensitive unit is p, the refractive index of the spacer layer is n, and the center wavelength d of the wavelength band of light to be separated by the color separation lens array is λ0, the theoretical thickness of the spacer layer is h t It is expressed by the following equation:

[0014] as well as

[0015] The actual thickness of the spacer layer h is t -p≤h≤h t +p range to select.

[0016] The sensor substrate may further include a third photosensitive unit and a fourth photosensitive unit configured to sense light, and the color separation lens array may further include a third region and a fourth region, wherein the third region faces the third photosensitive unit and includes a third nanopillar, and the fourth region faces the fourth photosensitive unit and may include a fourth nanopillar, and wherein at least one of a third size, a third shape, or a third arrangement of the third nanopillar may be different from at least one of a fourth size, a fourth shape, or a fourth arrangement of the fourth nanopillar.

[0017] The first to fourth nanopillars can form a phase distribution at the position where the light passes through the first area to the fourth area. Through the phase distribution, light with a first wavelength, light with a second wavelength, and light with a third wavelength, which are different from each other in the incident light incident on the color separation lens array, are branched to different directions, the light with the first wavelength is converged onto the first photosensitive unit and the fourth photosensitive unit, the light with the second wavelength is converged onto the second photosensitive unit, and the light with the third wavelength is converged onto the third photosensitive unit.

[0018] The light having the first wavelength may be green light, the light having the second wavelength may be blue light, and the light having the third wavelength may be red light.

[0019] For light of the first wavelength, the first to fourth nanocolumns can be formed at positions immediately after the light passes through the color separation lens array: a phase distribution of 2Nπ at positions corresponding to the center of the first photosensitive unit and the center of the fourth photosensitive unit, and a phase distribution of (2N-1)π at positions corresponding to the center of the second photosensitive unit and the center of the third photosensitive unit, where N is an integer greater than 0.

[0020] For light of the second wavelength, the first to fourth nanocolumns can be formed at positions immediately after the light passes through the color separation lens array: a phase distribution of (2M-1)π at positions corresponding to the center of the first photosensitive unit and the center of the fourth photosensitive unit, a phase distribution of 2Mπ at a position corresponding to the center of the second photosensitive unit, and a phase distribution greater than (2M-2)π and less than (2M-1)π at a position corresponding to the center of the third photosensitive unit, where M is an integer greater than 0.

[0021] For light of the third wavelength, the first to fourth nanocolumns can be formed at positions immediately after the light passes through the color separation lens array: a phase distribution of (2L-1)π at positions corresponding to the center of the first photosensitive unit and the center of the fourth photosensitive unit, a phase distribution of 2Lπ at a position corresponding to the center of the third photosensitive unit, and a phase distribution greater than (2L-2)π and less than (2L-1)π at a position corresponding to the center of the second photosensitive unit, where L is an integer greater than 0.

[0022] The image sensor may have a pixel arrangement structure in which a plurality of unit pixels including red pixels, green pixels, and blue pixels are arranged in a Bayer pattern, and among the first to fourth nanocolumns, the nanocolumns in the first to fourth regions corresponding to the green pixels may have different distribution rules in a first direction and in a second direction perpendicular to the first direction.

[0023] Among the first to fourth nanocolumns, the nanocolumns in the first to fourth regions corresponding to the blue and red pixels may have a symmetrical distribution rule in the first and second directions.

[0024] One of the first to fourth nanocolumns located at the center of an area corresponding to a green pixel among the first to fourth areas has a larger cross-sectional area than another of the first to fourth nanocolumns located in an area corresponding to a pixel of another color.

[0025] In an area corresponding to a green pixel among the first to fourth areas, one of the first to fourth nanopillars located at the center of the area may have a larger cross-sectional area than another one of the first to fourth nanopillars located at the periphery of the area.

[0026] The dichroic lens array may further include a plurality of first regions and a plurality of second regions, the plurality of first regions and the plurality of second regions being arranged to protrude from an edge of the sensor substrate and not facing any photosensitive unit of the sensor substrate in a vertical direction.

[0027] At least one of the first and second nanopillars includes a lower pillar and an upper pillar stacked on the lower pillar, and wherein the lower pillar and the upper pillar are stacked to be offset from each other.

[0028] The degree of offset between the lower pillars and the upper pillars may increase from a central portion to a peripheral portion of the image sensor.

[0029] According to one aspect of the present disclosure, an image sensor is provided, comprising: a sensor substrate, comprising a plurality of first photosensitive units and a plurality of second photosensitive units alternately arranged along a first row, and a plurality of third photosensitive units and a plurality of fourth photosensitive units alternately arranged along a second row adjacent to the first row; and a color separation lens array, comprising: a plurality of first regions, each facing the plurality of first photosensitive units and comprising a first nanocolumn; a plurality of second regions, each facing the plurality of second photosensitive units and comprising a second nanocolumn; a plurality of third regions, each facing the plurality of third photosensitive units and comprising a third nanocolumn; and a plurality of fourth regions, each facing the plurality of fourth photosensitive units and comprising a fourth nanocolumn, wherein at least one of the shapes, sizes, and arrangements of the first to fourth nanocolumns is configured such that: for light incident on the first For light incident in the second area, the light with the second wavelength is focused on the second photosensitive unit located directly below the first area, the light with the second wavelength is branched to the second photosensitive unit adjacent to the first photosensitive unit in the horizontal direction, and the light with the third wavelength is branched to the third photosensitive unit adjacent to the first photosensitive unit in the vertical direction, and for light incident in the second area, the light with the second wavelength is focused on the second photosensitive unit located directly below the second area, the light with the first wavelength is branched to the first photosensitive unit adjacent to the second photosensitive unit in the horizontal direction and to the fourth photosensitive unit adjacent to the second photosensitive unit in the vertical direction, and the light with the third wavelength is branched to the third photosensitive unit adjacent to the second photosensitive unit in the diagonal direction.

[0030] The light having the first wavelength may be green light, the light having the second wavelength may be blue light, and the light having the third wavelength may be red light.

[0031] According to one aspect of the present disclosure, there is provided an electronic device including: an image capture unit configured to focus light reflected from an object and form an optical image; and the image sensor discussed above configured to convert the optical image formed by the image capture unit into an electrical signal.

[0032] The electronic device may include a smartphone, a mobile phone, a personal digital assistant (PDA), a laptop computer, a personal computer (PC), a home appliance, a security camera, a medical camera, a vehicle, or an Internet of Things (IoT) device.

[0033] According to one aspect of the present disclosure, an image sensor is provided, comprising: a substrate comprising a first photosensitive unit and a second photosensitive unit configured to sense light; a color separation lens array disposed on the substrate, the color separation lens array comprising a first area overlapping with the first photosensitive unit in a plan view and a second area overlapping with the second photosensitive unit in a plan view; one or more first nanopillars disposed in a first arrangement in the first area; and one or more second nanopillars provided in a second arrangement in the second area, wherein at least one of a first dimension, a first size or a first arrangement of the one or more first nanopillars is different from at least one of a second size, a second shape or a second arrangement of the one or more first nanopillars.

[0034] Each of the one or more first nanopillars may include a lower pillar and an upper pillar stacked on the lower pillar, and wherein the lower pillar and the upper pillar may be stacked to be offset from each other, wherein the first offset may be a second offset, the first offset corresponding to the lower pillar and the upper pillar of the first one or more first nanopillars being closer to the center portion of the image sensor, and the second offset corresponding to the lower pillar and the upper pillar of the second one or more of the first nanopillars being farther away from the center portion of the first one or more of the first nanopillars.

[0035] According to one aspect of the present disclosure, an electronic device is provided, comprising: one or more optical elements configured to focus light reflected from an object and form an optical image; and an image sensor configured to convert the optical image formed by an image capture unit into an electrical signal, the image sensor comprising: a substrate comprising a first photosensitive unit and a second photosensitive unit configured to sense light; a color separation lens array disposed on the substrate, the color separation lens array comprising a first area overlapping with the first photosensitive unit in a plan view and a second area overlapping with the second photosensitive unit in a plan view; one or more first nanopillars disposed in a first arrangement in the first area; and one or more second nanopillars provided in a second arrangement in the second area, wherein at least one of a first dimension, a first size or a first arrangement of the one or more first nanopillars is different from at least one of a second size, a second shape or a second arrangement of the one or more first nanopillars.

[0036] According to one aspect of the present disclosure, a method for manufacturing an image sensor is provided, the method comprising: forming a first photosensitive unit and a second photosensitive unit on a substrate; forming a color separation lens array on the substrate, the color separation lens array comprising a first region overlapping with the first photosensitive unit in a plan view and a second region overlapping with the second photosensitive unit in a plan view; forming one or more first nanopillars in a first arrangement in the first region; and forming one or more second nanopillars in a second arrangement in the second region, wherein at least one of a first dimension, a first size, or a first arrangement of the one or more first nanopillars is different from at least one of a second size, a second shape, or a second arrangement of the one or more first nanopillars. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other aspects, features and advantages of some embodiments of the present disclosure will become more apparent from the following description in conjunction with the accompanying drawings, in which:

[0038] Figure 1 is a schematic block diagram of an image sensor according to example embodiments;

[0039] Figures 2A to 2C Various pixel arrangements of a pixel array of an image sensor according to example embodiments are shown;

[0040] Figure 3 is a conceptual diagram illustrating a schematic structure and operation of a dichroic lens array according to example embodiments;

[0041] Figure 4A and Figure 4B is a cross-sectional view of a pixel array of an image sensor according to example embodiments;

[0042] Figure 5A is a plan view illustrating an arrangement of photosensitive units in a pixel array of an image sensor according to example embodiments, Figure 5B is a plan view illustrating shapes of arrangements of a plurality of nanorods in a plurality of regions of a dichroic lens array in a pixel array of an image sensor according to example embodiments, and Figure 5C yes Figure 5B enlarged views and detailed plans of a portion of the

[0043] Figure 6A and Figure 6B is a diagram illustrating a computer simulation of a phase distribution shape of blue light passing through a dichroic lens array and a focus distribution of the blue light in a photosensitive unit facing the blue light according to example embodiments, Figure 6C shows a traveling direction of blue light incident on and around a second region of a dichroic lens array corresponding to a blue pixel according to example embodiments, and Figure 6DShown are a dichroic lens array for blue light and a microlens array functioning equivalently to the dichroic lens array according to example embodiments;

[0044] Figure 7A and Figure 7B is a diagram illustrating a computer simulation of a phase distribution shape of green light passing through a dichroic lens array and a focus distribution of green light in a photosensitive unit facing the green light according to example embodiments, Figure 7C shows a traveling direction of green light incident on and around first and fourth areas of a dichroic lens array corresponding to a green pixel according to example embodiments, and Figure 7D Shown are a dichroic lens array for green light and a microlens array that functions equivalently to the dichroic lens array according to example embodiments;

[0045] Figure 8A and Figure 8B is a diagram illustrating a computer simulation of a phase distribution shape of red light passing through a dichroic lens array and a focus distribution of red light in a photosensitive unit facing the red light according to example embodiments, Figure 8C shows a traveling direction of red light incident on and around a third area of ​​a dichroic lens array corresponding to a red pixel according to an example embodiment, and Figure 8D Shown are a dichroic lens array for red light and a microlens array that functions equivalently to the dichroic lens array according to example embodiments;

[0046] Figure 9A 、 Figure 9B and Figure 9C illustrates a traveling direction of light of each color incident on a region corresponding to a blue pixel, a region corresponding to a green pixel, and a region corresponding to a red pixel according to example embodiments;

[0047] Figures 10A to 10E is a graph showing a change in the efficiency of the dichroic lens array according to the distance between the dichroic lens array and the sensor substrate when the pitch of each photosensitive unit is 0.7 μm;

[0048] Figures 11A to 11E is a graph showing a change in the efficiency of the dichroic lens array according to the distance between the dichroic lens array and the sensor substrate when the pitch of each photosensitive unit is 0.8 μm;

[0049] 12A to 12E is a graph showing a change in the efficiency of the dichroic lens array according to the distance between the dichroic lens array and the sensor substrate when the pitch of each photosensitive unit is 1.0 μm;

[0050] Figure 13is a perspective view illustrating exemplary shapes of nanorods that may be employed in a dichroic lens array according to example embodiments;

[0051] 14A to 14H is a plan view illustrating exemplary shapes of nanorods that may be employed in a dichroic lens array of an image sensor according to example embodiments;

[0052] Figure 15 is a plan view illustrating an arrangement shape of nanorods constituting a dichroic lens array according to another example embodiment;

[0053] Figure 16 is a plan view illustrating an arrangement shape of nanorods constituting a dichroic lens array according to another example embodiment;

[0054] Figure 17 is a plan view illustrating an arrangement shape of nanorods constituting a dichroic lens array according to another example embodiment;

[0055] Figure 18 is a plan view illustrating an arrangement shape of a plurality of nanorods constituting a dichroic lens array according to another example embodiment;

[0056] Figure 19 It shows the incident Figure 18 a graph of spectral distribution of light on each of red pixels, green pixels, and blue pixels of an image sensor including a dichroic lens array;

[0057] Figure 20A and Figure 20B is a cross-sectional view of a schematic structure of a pixel array according to another example embodiment;

[0058] Figure 21 and Figure 22 is a graph showing spectral distribution of light incident on red, green, and blue pixels of an image sensor, and respectively showing the spectral distributions of an embodiment in which a color filter is provided and an embodiment in which no color filter is provided;

[0059] Figure 23 is a plan view showing a dichroic lens array according to another example embodiment;

[0060] Figure 24 It is shown that Figure 23 A cross-sectional view of a schematic structure of a pixel array of an image sensor including a dichroic lens array is shown;

[0061] Figure 25 is a cross-sectional view illustrating a schematic structure of an image sensor according to another example embodiment;

[0062] Figure 26It is shown in Figure 25 A perspective view of exemplary shapes of nanopillars employed in a dichroic lens array of an image sensor;

[0063] Figure 27 is a block diagram schematically illustrating an electronic device including an image sensor according to example embodiments; and

[0064] Figures 28 to 38 Various examples of multimedia electronic devices to which the image sensor according to example embodiments is applied are illustrated. DETAILED DESCRIPTION

[0065] With reference now in detail to example embodiments, examples of embodiments are shown in the accompanying drawings, and the same reference numerals refer to the same elements throughout the accompanying drawings. In this regard, exemplary embodiments may have different forms and should not be construed as being limited to the description set forth herein. Therefore, example embodiments will be described below only with reference to the accompanying drawings to explain various aspects. As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items. Statements such as "at least one of..." modify the entire element list when following the element list, rather than modifying the individual elements in the list.

[0066] Hereinafter, an image sensor including a dichroic lens array and an electronic device including the image sensor will be described in detail with reference to the accompanying drawings. The exemplary embodiments described below are merely examples, and various modifications may be made to these exemplary embodiments. In the following drawings, like reference numerals refer to like elements, and the dimensions of components in the drawings may be exaggerated for clarity and ease of description.

[0067] Hereinafter, expressions described as “on…” or “on…” may include not only direct contact but also non-contact. For example, expressions described as “on…” or “on…” may include not only a first element being in direct contact with a second element above, below, on the left, or on the right, but also a first element being in non-contact with the second element above, below, on the left, or on the right.

[0068] It should be understood that although the terms "first," "second," etc. may be used herein to describe various components, these components should not be limited by these terms. These components are only used to distinguish components from each other. These terms do not limit the materials or structures of the components to be different from each other.

[0069] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when a part is referred to as "including" another component, unless the context indicates otherwise, the part may not exclude the other component but may also include the other component.

[0070] In addition, the terms "... unit" and "... module" used herein designate a unit for processing at least one function or operation, and this can be implemented by hardware or software, or a combination of hardware and software.

[0071] The use of the term "above" and similar referential terms may correspond to both the singular and the plural.

[0072] Unless the context clearly indicates that the operations must be performed in the order described, the operations constituting the method may be performed in an appropriate order. In addition, the use of all exemplary terms (e.g., etc.) is only to describe the technical spirit in detail, and the scope of rights is not limited by these terms unless the context is limited by the claims.

[0073] Figure 1 is a schematic block diagram of an image sensor according to an example embodiment. Figure 1 , the image sensor 1000 may include a pixel array 1100, a timing controller (TC) 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.

[0074] The pixel array 1100 may include pixels arranged in two dimensions along multiple rows and columns. The row decoder 1020 may select a row from the rows of the pixel array 1100 in response to a row address signal output from the timing controller 1010. The output circuit 1030 may output a photosensitive signal from multiple pixels arranged along the selected row in columns. 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 multiple ADCs arranged in columns between the column decoder and the pixel array 1100, or an ADC arranged at the output end of the column decoder. The timing controller 1010, the row decoder 1020, and the output circuit 1030 may be implemented as a single chip or a separate chip. A processor for processing an image signal output by the output circuit 1030 may be implemented as a single chip together with the timing controller 1010, the row decoder 1020, and the output circuit 1030.

[0075] The pixel array 1100 may include a plurality of pixels that detect light having different wavelengths. Figures 2A to 2C As shown, multiple pixels can be arranged in various ways.

[0076] Figure 2A 1 shows a Bayer pattern provided in the image sensor 1000 according to example embodiments. Figure 2A , a unit pixel of the pixel array 1100 may include four quadrant areas, and the first to fourth quadrants may be blue pixels B, green pixels G, red pixels R, and green pixels G, respectively. These unit pixels may be two-dimensionally repeated in a first direction (X direction) and a second direction (Y direction). In other words, two green pixels G may be arranged in a diagonal direction within a 2×2 array type unit pixel, and one blue pixel B and one red pixel R may be arranged in another diagonal direction. Observing the overall pixel arrangement of the pixel array 1100, it may be repeated to have: a first row in which a plurality of green pixels G and a plurality of blue pixels B are alternately arranged in 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 in the first direction.

[0077] However, the arrangement method of the pixel array 1100 is not limited to the Bayer pattern, and various arrangement methods other than the Bayer pattern are also possible. Figure 2B , in which a magenta pixel M, a cyan pixel C, a yellow pixel Y, and a green pixel G constitute a unit pixel CYGM method arrangement is also feasible. Figure 2C An arrangement of an RGBW method 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.

[0078] although Figures 2A to 2C The unit pixel may have a 2×2 array shape, but the present disclosure is not limited thereto. According to another exemplary embodiment, the unit pixel may have a 3×2 array shape. In addition, the pixels in the pixel array 1100 may be arranged in various ways according to the color characteristics of the image sensor 1000. Hereinafter, for convenience, the pixel array 1100 of the image sensor 1000 has a Bayer pattern. However, the principles of the embodiments described below may be applied to pixel arrangements other than the Bayer pattern.

[0079] According to an embodiment, the pixel array 1100 of the image sensor 1000 may include a color separation lens array configured to condense light of a color corresponding to each pixel. Figure 3 : is a conceptual diagram showing a schematic structure and operation of a dichroic lens array according to an embodiment. Figure 3The dichroic lens array 130 may include nanorods NP. According to example embodiments, the dichroic lens array 130 may include nanorods NP arranged on the same plane according to a specific rule. According to example embodiments, the specific rule may be a predetermined rule. According to example embodiments, the dichroic lens array 130 may be arranged on the spacer layer 120.

[0080] Here, the incident light L can be dichroic by the dichroic lens array 130. i The parameters such as the shape, size (width, height), spacing and arrangement of the nanopillars NP are determined by the target phase distribution TP to be achieved on the nanopillars NP. i The target phase distribution TP is determined by the first target region R1 and the second target region R2. The target phase distribution TP is shown between the dichroic lens array 130 and the first target region R1 and the second target region R2, but this is only for ease of explanation. The actual target phase distribution TP may refer to the phase distribution immediately before the incident light L i The phase distribution at a position after passing through the dichroic lens array 130 , for example, the phase distribution on the bottom surface of the dichroic lens array 130 or the top surface of the spacer layer 120 .

[0081] The color separation lens array 130 may include a first region 131 and a second region 132, and each of the first region 131 and the second region 132 may include one or more nanopillars NP. 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 in a one-to-one manner. Although three nanopillars NP are shown as being arranged in the first region 131 and the second region 132, respectively, this is exemplary and the present disclosure is not limited thereto. Moreover, although the nanopillars NP are shown as being completely located in one of the first region 131 and the second region 132, the present disclosure is not limited thereto, and some nanopillars NP may be arranged at the boundary between the first region 131 and the second region 132.

[0082] The nanorods NP of the dichroic lens array 130 can be formed on the incident light L i The phase distribution in which light with different wavelengths included in the target phase distribution is branched and converged in different directions. For example, the shape, size, and arrangement of the nanorods NP distributed in the first region 131 and the second region 132 can be determined to form a target phase distribution TP, in which the incident light L i The first wavelength light L included in λ1 With incident light L i The first phase distribution and the second wavelength light L λ2 According to the target phase distribution TP, the light of the first wavelength L λ1 and the second wavelength of light Lλ2 The nanorods NP may converge at target regions R1 and R2 at a certain separation distance A from the nanorods NP, respectively.

[0083] According to example embodiments, the focused light L of the first wavelength is concentrated according to the target phase distribution TP. λ1 and the second wavelength of light L λ2 The light L of the first wavelength may be concentrated at the target regions R1 and R2 at a certain separation distance A from the nanorods NP. λ1 and the second wavelength of light L λ2 According to example embodiments, the light L of the first wavelength that is focused is, according to the target phase distribution TP, λ1 and the second wavelength of light L λ2 The light L of the first wavelength may be focused at the target regions R1 and R2 at a certain separation distance A from the nanorods NP. λ1 and the second wavelength of light L λ2 .

[0084] According to example embodiments, the nanorods NP of the dichroic lens array 130 may be formed on the incident light L i The phase distribution in which light with different wavelengths is divided and converged in different directions is included.

[0085] According to example embodiments, a rule in which the nanopillars NPs are arranged in the first region 131 may be different from a rule in which the nanopillars NPs are arranged in the second region 132. In other words, one of the shape, size, and arrangement of the nanopillars NPs disposed in the first region 131 may be different from the shape, size, and arrangement of the nanopillars NPs disposed in the second region 132.

[0086] The nanorod NP may have a shape size smaller than the sub-wavelength of the wavelength band to be branched. The nanorod NP may have a shape size smaller than the shorter wavelength of the first wavelength and the second wavelength, and for example, when the incident light L i When visible light is present, the nanopillar NP may have a size smaller than 400 nm, 300 nm, or 200 nm.

[0087] Nanopillar NP can be made of a material with a refractive index higher than that of the surrounding material. For example, nanopillar NP can be made of c-Si, p-Si, a-Si and III-V compound semiconductors (GaP, GaN, GaAs, etc.), SiC, TiO2, SiN and / or a combination thereof. Nanopillar NP having a different refractive index from the surrounding material can change the phase of the light passing through. This is due to the phase delay caused by the shape size of the sub-wavelength, and the degree of phase delay can be determined by the detailed shape size and arrangement shape of the nanopillar NP. The surrounding material can be made of a dielectric material with a lower refractive index than the nanopillar NP, for example, SiO2 or air.

[0088] According to example embodiments, the first wavelength λ1 and the second wavelength λ2 may be in the visible light wavelength band. However, embodiments are not limited thereto, and various wavelength bands may be implemented according to the shape, size, interval, and arrangement of the arranged nanopillars NP. Figure 3 It is shown that two wavelengths of light are branched and converged. However, the embodiment is not limited thereto, and the incident light may be branched and converged in three or more directions according to the wavelength.

[0089] Hereinafter, an example in which the above-described dichroic lens array 130 is applied to the pixel array 1100 of the image sensor 1000 will be described in more detail.

[0090] Figure 4A and Figure 4B is a cross-sectional view of a pixel array according to example embodiments, Figure 5A is a plan view illustrating an arrangement of photosensitive units of a pixel array according to example embodiments, and Figure 5B is a plan view illustrating the shape of an arrangement of nanorods of a dichroic lens array according to example embodiments.

[0091] Reference Figure 4A and Figure 4B , the pixel array 1100 may include: a sensor substrate 110 including a plurality of light sensing units 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. Figure 5A In the illustrated example embodiment, the photosensitive units 111 and 112 may be arranged in one row, and the photosensitive units 113 and 114 may be arranged in another row.

[0092] The sensor substrate 110 may include a first photosensitive unit 111, a second photosensitive unit 112, a third photosensitive unit 113, and a fourth photosensitive unit 114 that convert light into an electrical signal. These photosensitive units, for example, Figure 4A As shown, the first photosensitive unit 111 and the second photosensitive unit 112 may be alternately arranged in the first direction (X direction), and in a cross section having different Y direction positions, as shown in FIG. Figure 4BAs shown, the third photosensitive unit 113 and the fourth photosensitive unit 114 can be arranged alternately. This area division is used to sense incident light by pixel unit. For example, the first photosensitive unit 111 and the fourth photosensitive unit 114 can sense light having a first wavelength corresponding to the first pixel, the second photosensitive unit 112 can sense light having a second wavelength corresponding to the second pixel, and the third photosensitive unit 113 can sense light having a third wavelength corresponding to the third pixel. In the following, light having a first wavelength is shown as green light, light having a second wavelength is shown as blue light, and light having a third wavelength is shown as red light, and the first pixel, the second pixel and the third pixel are shown as green pixel G, blue pixel B and red pixel R, respectively. According to example embodiments, a separator for the separation unit may be further formed on the sensor substrate 110.

[0093] The spacer layer 120 can be configured to maintain a distance h between the sensor substrate 110 and the dichroic lens array 130 while supporting the dichroic lens array 130, and can be made of a material transparent to visible light. For example, the spacer layer 120 can be made of a dielectric material having a refractive index lower than that of the nanorods NP of the dichroic lens array 130 (e.g., SiO2, siloxane-based spin-on-glass (SOG)) and low absorptivity in the visible light band.

[0094] The dichroic lens array 130 may include nanopillars NP arranged according to a specific rule. According to example embodiments, the dichroic lens array 130 may further include a protective layer for protecting the nanopillars NP. The protective layer may be made of a dielectric material having a lower refractive index than the material used to form the nanopillars NP.

[0095] The dichroic lens array 130 may be divided into a plurality of regions 131, 132, 133, and 134 facing the plurality of photosensitive units 111, 112, 113, and 114 in a one-to-one correspondence. One or more nanopillars NP may be arranged in each of the plurality of regions 131, 132, 133, and 134, and any one of the shape, size, and arrangement of the nanopillars NP may be different from one region to another.

[0096] According to example embodiments, the area of ​​the color separation lens array 130 can be divided so that light with a first wavelength can be branched and converged onto the first photosensitive unit 111 and the fourth photosensitive unit 114, light with a second wavelength can be branched and converged onto the second photosensitive unit 112, and light with a third wavelength can be branched and converged onto the third photosensitive unit 113, and the size, shape and arrangement of the nanopillars NP can be determined according to the area.

[0097] When the pixel array 1100 has Figure 2A The Bayer pattern shown Figure 5A The first photosensitive unit 111 and the fourth photosensitive unit 114 may correspond to the green pixel G, the second photosensitive unit 112 may correspond to the blue pixel B, and the third photosensitive unit 113 may correspond to the red pixel R. Figure 5B , the first area 131 and the fourth area 134 of the dichroic lens array 130 may correspond to the green pixel G, the second area 132 of the dichroic lens array 130 may correspond to the blue pixel B, and the third area 133 of the dichroic lens array 130 may correspond to the red pixel R. Therefore, the dichroic lens array 130 may include a plurality of unit pattern arrays arranged two-dimensionally, and each of the plurality of unit pattern arrays may include a first area 131, a second area 132, a third area 133, and a fourth area 134 arranged in a 2×2 form.

[0098] like Figure 5B As shown, first region 131 and fourth region 134 corresponding to green pixel G, second region 132 corresponding to blue pixel B, and third region 133 corresponding to red pixel R may include cylindrical nanopillars NP having a circular cross-section. Nanopillars NP having different cross-sectional areas may be arranged in the center of first region 131, second region 132, third region 133, and fourth region 134, and may be arranged in the center of the boundary between pixels and at the intersection of the pixel boundaries. The cross-sectional area of ​​the nanopillars NP arranged at the boundary between pixels may be smaller than the cross-sectional area of ​​the nanopillars NP arranged in the center of the pixel.

[0099] Figure 5C The details of the nanopillar NP are shown in Figure 5B In some areas, that is, in the first to fourth areas 131, 132, 133 and 134 constituting the unit pattern array. Figure 5C In FIG, the nanopillars NP are represented by p1 to p9 according to the detailed positions in the unit pattern array. Figure 5C , among the nanopillars NP, the cross-sectional areas of the nanopillar p1 arranged at the center of the first region 131 and the nanopillar p4 arranged at the center of the fourth region 134 may be larger than the cross-sectional areas of the nanopillar p2 arranged at the center of the second region 132 or the nanopillar p3 arranged at the center of the third region 133, and the cross-sectional area of ​​the nanopillar p2 arranged at the center of the second region 132 may be larger than the cross-sectional area of ​​the nanopillar p3 arranged at the center of the third region 133. However, this is merely an example, and nanopillars NP having various shapes, sizes, and arrangements may be applied if necessary.

[0100] The nanopillars NP arranged in the first region 131 and the fourth region 134 corresponding to the green pixel G may have different distribution rules in the first direction (X direction) and the second direction (Y direction). For example, the nanopillars NP arranged in the first region 131 and the fourth region 134 may have different size arrangements in the first direction (X direction) and the second direction (Y direction). Figure 5C As shown, among the nanopillars NP, the cross-sectional area of ​​a nanopillar p5 located at the boundary between a first region 131 and a second region 132 adjacent to the first region 131 in the first direction (X direction) may be different from the cross-sectional area of ​​a nanopillar p6 located at the boundary between the first region 131 and a third region 133 adjacent to the first region 131 in the second direction (Y direction). Similarly, the cross-sectional area of ​​a nanopillar p7 located at the boundary between the third region 133 and a fourth region 134 adjacent to the third region 133 in the first direction (X direction) may be different from the cross-sectional area of ​​a nanopillar p8 located at the boundary between the third region 133 and the second region 132 adjacent to the third region 133 in the second direction (Y direction).

[0101] On the other hand, the nanopillars NP arranged in the second region 132 corresponding to the blue pixel B and in the third region 133 corresponding to the red pixel R may have a symmetrical distribution rule in the first direction (X direction) and the second direction (Y direction). Figure 5C As shown, in the nanopillar NP, the cross-sectional area of ​​the nanopillar p5 located at the boundary between pixels adjacent to the second region 132 in the first direction (X direction) can be the same as the cross-sectional area of ​​the nanopillar p8 located at the boundary between pixels adjacent to the second region 132 in the second direction (Y direction), and the cross-sectional area of ​​the nanopillar p7 located at the boundary between pixels adjacent to the third region 133 in the first direction (X direction) can be the same as the cross-sectional area of ​​the nanopillar p6 located at the boundary between pixels adjacent to the third region 133 in the second direction (Y direction).

[0102] Also, the nanopillars P9 arranged at four edges of each of the first, second, third, and fourth regions 131 , 132 , 133 , and 134 (ie, where the four regions cross each other) may have the same cross-sectional area.

[0103] Figure 5CThe distribution of nanopillars NP in the image is arranged according to the Bayer pattern. For both blue pixels B and red pixels R, adjacent pixels in the first direction (X direction) and the second direction (Y direction) are identical to green pixels G. However, for green pixels G corresponding to first region 131, adjacent pixels in the first direction (X direction) are blue pixels B, and adjacent pixels in the second direction (Y direction) are different red pixels R. For green pixels G corresponding to fourth region 134, adjacent pixels in the first direction (X direction) are red pixels R, and adjacent pixels in the second direction (Y direction) are different blue pixels B. For green pixels G corresponding to first region 131 and fourth region 134, adjacent pixels in the four diagonal directions are identical green pixels G. For blue pixels B corresponding to second region 132, adjacent pixels in the four diagonal directions are identical red pixels R. And for red pixels R corresponding to third region 133, adjacent pixels in the four diagonal directions are identical blue pixels B. Therefore, in the second region 132 and the third region 133 corresponding to the blue pixel B and the red pixel R, respectively, the nanopillars NP may be arranged in a 4-fold symmetric form, and in the first region 131 and the fourth region 134 corresponding to the green pixel G, the nanopillars NP may be arranged in a 2-fold symmetric form. In particular, the first region 131 and the fourth region 134 may be rotated 90 degrees relative to each other.

[0104] Although the nanopillars NP have a symmetrical circular cross-sectional shape according to example embodiments, the present disclosure is not limited thereto and may include some nanopillars having asymmetrical cross-sectional shapes. For example, in the first region 131 and the fourth region 134 corresponding to the green pixel G, nanopillars having asymmetrical cross-sectional shapes with different widths in the first direction (X direction) and the second direction (Y direction) may be employed, and in the second region 132 and the third region 133 corresponding to the blue pixel B and the red pixel R, respectively, nanopillars having symmetrical cross-sectional shapes with the same width in the first direction (X direction) and the second direction (Y direction) may be employed.

[0105] The arrangement pattern of the dichroic lens array 130 is an example for achieving the target phase distribution in which light of a first wavelength is branched and focused on the first photosensitive unit 111 and the fourth photosensitive unit 114, light of a second wavelength is branched and focused on the second photosensitive unit 112, and light of a third wavelength is branched and focused on the third photosensitive unit 113. The arrangement pattern of the dichroic lens array 130 is not limited to the illustrated pattern. The arrangement pattern may be provided according to a specific rule.

[0106] The shape, size and arrangement of the nanopillars NP in each area of ​​the color separation lens array 130 can be determined so that light with a first wavelength can form a phase at the position where the light passes through the color separation lens array 130, and the light with the first wavelength is converged onto the first photosensitive unit 111 and the fourth photosensitive unit 114 through the phase and does not proceed to the adjacent second photosensitive unit 112 and the third photosensitive unit 113.

[0107] The shape, size and arrangement of the nanopillars NP in each area of ​​the color separation lens array 130 can be determined so that light with the second wavelength can form a phase at the position where the light passes through the color separation lens array 130, and the light with the second wavelength is converged onto the second photosensitive unit 112 through the phase and does not proceed to the adjacent first photosensitive unit 111, third photosensitive unit 113 and fourth photosensitive unit 114.

[0108] In addition, similarly, the shape, size and arrangement of the nanopillars NP in each area of ​​the color separation lens array 130 can be determined so that light with a third wavelength can form a phase at the position where the light passes through the color separation lens array 130, and the light with the third wavelength converges onto the third photosensitive unit 113 through the phase and does not proceed to the adjacent first photosensitive unit 111, second photosensitive unit 112 and fourth photosensitive unit 114.

[0109] The shape, size, and / or arrangement of the nanopillars NP that satisfies all of these conditions can be determined, and the light immediately after passing through the dichroic lens array 130 can have the following target phase distribution. The phase of the light having the first wavelength immediately after passing through the dichroic lens array 130, in other words, the phase of the light having the first wavelength on the bottom surface of the dichroic lens array 130 or the top surface of the spacer layer 120 can be 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 can be (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 light having a first wavelength immediately after passing through the dichroic lens array 130 may be maximized at the center of the first region 131 and the center of the fourth region 134, and as the distance from the center of the first region 131 and the center of the fourth region 134 gradually decreases in a concentric circle shape, the phase of light having the first wavelength may be minimized at the center of the second region 132 and the center of the third region 132. For example, when N=1, the phase of green light passing through the dichroic lens array 130 may be 2π at the center of the first region 131 and the center of the fourth region 134, and may be π at the center of the second region 132 and the center of the third region 133. Here, the phase may refer to a phase value relative to the phase of the light immediately before passing through the nanorods NP.

[0110] In addition, the phase of the light having the second wavelength immediately after passing through the dichroic lens array 130 may be 2Mπ at the center of the second region 132 corresponding to the second photosensitive unit 112, (2M-1)π at the center of the first region 131 corresponding to the first photosensitive unit 111, and (2M-1)π at the center of the fourth region 134 corresponding to the fourth photosensitive unit 114, and may be greater than (2M-2)π and less than (2M-1)π at the center of the third region 133 corresponding to the third photosensitive unit 113. Here, M is an integer greater than 0. In other words, the phase of the light having the second wavelength immediately after passing through the dichroic lens array 130 may be maximized at the center of the second region 132, and as the distance from the center of the second region 132 gradually decreases in a concentric circle shape, the phase of the light having the second wavelength may be locally minimized at the centers of the first region 131, the fourth region 134, and the third region 133. For example, when M=1, the phase of blue light passing through the dichroic lens array 130 may be 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 approximately 0.7π at the center of the third region 133 .

[0111] Similarly, the phase of the light having the third wavelength immediately after passing through the dichroic lens array 130 may be 2Lπ at the center of the third region 133 corresponding to the third photosensitive unit 113, (2L-1)π at the center of the first region 131 corresponding to the first photosensitive unit 111, and (2L-1)π at the center of the fourth region 134 corresponding to the fourth photosensitive unit 114, and may be greater than (2L-2)π and less than (2L-1)π at the center of the second region 132 corresponding to the second photosensitive unit 112. Here, L is an integer greater than 0. In other words, the phase of the light having the third wavelength immediately after passing through the dichroic lens array 130 may be maximized at the center of the third region 133, and as the distance from the center of the third region 133 gradually decreases in a concentric circle shape, the phase of the light having the third wavelength may be locally minimized at the centers of the first region 131, the fourth region 134, and the second region 132. For example, when L=1, the phase of red light passing through the dichroic lens array 130 may be 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 .

[0112] As described above, the target phase distribution refers to the phase distribution of light immediately after passing through the dichroic lens array 130. When the light passing through the dichroic lens array 130 has this phase distribution, light having the first to fourth wavelengths can be respectively converged onto the first photosensitive unit 111, the second photosensitive unit 112, the third photosensitive unit 113, and the fourth photosensitive unit 114. In other words, the light passing through the dichroic lens array 130 can achieve the same optical effect as if it were branched according to wavelength, traveled in different directions, and converged.

[0113] According to example embodiments, a certain travel distance requirement may be determined so that light having a corresponding wavelength may converge onto a corresponding photosensitive unit. Therefore, the thickness h of the spacer layer 120 may be determined accordingly. For example, according to example embodiments, the thickness h of the spacer layer 120 may be changed according to the wavelength λ to be branched, the pixel size, and the arrangement period p of the photosensitive units. The thickness h of the spacer layer 120 may be greater than the center wavelength λ of the wavelength band of visible light to be branched, and when compared with the photosensitive unit arrangement period p, which is the distance between the centers of adjacent photosensitive units, the thickness h of the spacer layer 120 may be in the range of 1p to 3p. In detail, the thickness h of the spacer layer 120 may be between 500nm and 5μm. This will be referred to later. Figures 10A to 10E 、 Figures 11A to 11E as well as 12A to 12E More details for setting the thickness h of the spacer layer 120 are described below.

[0114] Figure 6A and Figure 6Bis a diagram illustrating a computer simulation of a phase distribution shape of blue light passing through a dichroic lens array and a focus distribution of the blue light in a photosensitive unit facing the blue light according to example embodiments, Figure 6C shows a traveling direction of blue light incident on and around a second region of a dichroic lens array corresponding to a blue pixel B according to an example embodiment, and Figure 6D A dichroic lens array for blue light and a microlens array functioning equivalently to the dichroic lens array according to example embodiments are shown.

[0115] according to Figure 6A In the phase distribution shown, the phase of the blue light at the center of the area corresponding to the blue pixel B can be approximately 2π, and the phase of the blue light at the center of the area corresponding to the adjacent green pixel G can be approximately π, and the phase of the blue light at the center of the area corresponding to the red pixel R in the diagonal direction can be approximately less than π (for example, approximately 0.2π to 0.7π).

[0116] The phase distribution can be expressed as Figure 6B The focusing distribution of blue light is shown in FIG. Most of the blue light can be focused on the area corresponding to the blue pixel B, and the blue light almost does not reach the areas corresponding to other pixels.

[0117] Results, such as Figure 6C As shown, blue light incident on and around the second region 132 corresponding to the blue pixel B passes through the dichroic lens array 130 and then travels toward the second photosensitive unit. For example, of the incident light on the second region 132 of the dichroic lens array 130 and a portion of the other regions surrounding the second region 132, the blue light may be focused on the second photosensitive unit 112 directly below the second region 132. In other words, blue light from the second region 132 corresponding to the blue pixel B, blue light from the two first regions 131 adjacent to the second region 132 in the horizontal direction, blue light from the two fourth regions 134 adjacent to the second region 132 in the vertical direction, and blue light from the four third regions 113 adjacent to the second region 132 in the diagonal direction are incident on a single blue pixel B.

[0118] Therefore, if Figure 6DAs shown, for blue light, the dichroic lens array 130 can function equivalently to an array of multiple microlenses ML1 arranged around the second photosensitive cell 112. Because each equivalent microlens ML1 is larger than the corresponding second photosensitive cell 112, blue light incident on another area surrounding the second photosensitive cell 112 and blue light incident on the area of ​​the second photosensitive cell 112 can also be focused onto the second photosensitive cell 112. For example, each microlens ML1 can be approximately four times the size of the corresponding second photosensitive cell 112, and the four sides of each microlens ML1 can be parallel to the four sides of the second photosensitive cell 112.

[0119] Figure 7A and Figure 7B is a diagram showing a computer simulation of the phase distribution shape of green light passing through the dichroic lens array and the focus distribution of green light in the photosensitive unit facing the green light, Figure 7C shows the traveling direction of green light incident on and around the first and fourth regions of the dichroic lens array corresponding to the green pixel, and Figure 7D A dichroic lens array for green light and a microlens array that functions equivalently to the dichroic lens array are shown.

[0120] according to Figure 7A In the phase distribution shown, the phase of green light at the center of the region corresponding to the green pixel G may be approximately 2π, and the phase of green light at the centers of the regions corresponding to the adjacent blue pixel B and red pixel R may be approximately π.

[0121] The phase distribution can be expressed as Figure 7B The green light can be focused on the areas corresponding to the two green pixels G, and the green light hardly reaches the areas corresponding to the other pixels.

[0122] Results, such as Figure 7C As shown, green light incident on and around the first and fourth regions 131, 134 corresponding to the green pixel G passes through the dichroic lens array 130 and then travels to the first photosensitive unit 111. For example, of the light incident on the first region 131 of the dichroic lens array 130 and a portion of other regions surrounding the first region 131, the green light may be focused on the first photosensitive unit 111 directly below the first region 131. In other words, green light from the first region 131 or the fourth region 134 corresponding to the green pixel G, and green light from the two second regions 132 and the two third regions 133 adjacent to the first region 131 or the fourth region 134 in the horizontal and vertical directions, is incident on one green pixel G.

[0123] Therefore, if Figure 7DAs shown, for green light, the dichroic lens array 130 can function equivalently to an array of a plurality of microlenses ML2 arranged around the first photosensitive cell 111 and the fourth photosensitive cell 114. Since each equivalent microlens ML2 is larger than the corresponding first photosensitive cell 111 or fourth photosensitive cell 114, green light incident on another area surrounding the first photosensitive cell 111 and the fourth photosensitive cell 114, as well as green light incident on the first photosensitive cell 111 and the fourth photosensitive cell 114, can also be focused onto the first photosensitive cell 111 and the fourth photosensitive cell 114. For example, each microlens ML2 can be approximately twice the size of the corresponding first photosensitive cell 111 or the fourth photosensitive cell 114 and can be arranged diagonally adjacent to the corresponding first photosensitive cell 111 or the fourth photosensitive cell 114.

[0124] Figure 8A and Figure 8B is a diagram showing a computer simulation of the phase distribution shape of red light passing through the dichroic lens array and the focus distribution of red light in the photosensitive unit facing the red light, Figure 8C shows the traveling direction of red light incident on and around the third area of ​​the dichroic lens array corresponding to the red pixel, and Figure 8D A dichroic lens array for red light and a microlens array that functions equivalently to the dichroic lens array are shown.

[0125] according to Figure 8A In the phase distribution shown, the phase of the red light at the center of the area corresponding to the red pixel R can be approximately 2π, and the phase of the red light at the center of the area corresponding to the adjacent green pixel G can be approximately π, and the phase of the red light at the center of the area corresponding to the blue pixel B in the diagonal direction can be approximately less than π (for example, approximately 0.2π to 0.7π).

[0126] The phase distribution can be expressed as Figure 8B The focusing distribution of red light is shown in FIG. The red light can be focused on the area corresponding to the red pixel R, and the red light hardly reaches the areas corresponding to other pixels.

[0127] Results, such as Figure 8CAs shown, light incident on and around the third region 133 corresponding to the red pixel R passes through the dichroic lens array 130 and then travels. For example, among the incident light incident on the third region 133 of the dichroic lens array 130 and a portion of the other regions surrounding the third region 133, red light may be focused on the third photosensitive unit 113 directly below the third region 133. In other words, red light from the third region 133 corresponding to the red pixel R, red light from two fourth regions 134 adjacent to the third region 133 in the horizontal direction, red light from two first regions 131 adjacent to the third region 133 in the vertical direction, and red light from four second regions 132 adjacent to the third region 133 in the diagonal direction are incident on one red pixel R.

[0128] Therefore, if Figure 8D As shown, for red light, the dichroic lens array 130 can function equivalently to an array of multiple microlenses ML3 arranged around the third photosensitive cell 113. Because each equivalent microlens ML3 is larger than the corresponding third photosensitive cell 113, red light incident on another area around the third photosensitive cell 113 and red light incident on the area of ​​the third photosensitive cell 113 can also be focused onto the third photosensitive cell 113. For example, each microlens ML3 can be approximately four times the size of the corresponding third photosensitive cell 113, and the four sides of each microlens ML3 can be parallel to the four sides of the third photosensitive cell 113.

[0129] Figure 6C 、 Figure 7C and Figure 8C The paths of blue light, green light, and red light described in may have a shape in which light incident on each region is branched for each color, and may be described as follows.

[0130] Figure 9A The traveling direction of light of each color incident on the area corresponding to the blue pixel is shown. Figure 9A , when the light L incident on the second region 132 corresponding to the blue pixel B i Medium, Blue Light L B The incident light L enters the second region 132 and travels to the second photosensitive unit 112 directly below the second region 132. i Middle, Green Light L G Most of the light travels to the two first photosensitive units 111 adjacent to the second photosensitive unit 112 in the horizontal direction and the two fourth photosensitive units 114 adjacent to the second photosensitive unit 112 in the vertical direction. i Middle, red light L R Most of the light travels to four third photosensitive units 113 adjacent to the second photosensitive unit 112 in the diagonal direction.

[0131] Figure 9B The traveling direction of light of each color incident on the area corresponding to the green pixel is shown. Figure 9B , when the light L incident on the first region 131 corresponding to the green pixel G i Middle, Green Light L G The incident light L on the first region 131 travels to the first photosensitive unit 111 directly below the first region 131. i Medium, Blu-ray L B The red light L travels to the two second photosensitive units 112 adjacent to the first photosensitive unit 111 in the horizontal direction, and R Most of the light travels to two third photosensitive units 113 adjacent to the first region 111 in the vertical direction.

[0132] Figure 9C The direction of travel of light incident on the region corresponding to the red pixel is shown. i Middle, red light L R The incident light L enters the third region 133 and travels to the third photosensitive unit 113 directly below the third region 133. i Middle, Green Light L G The incident light L travels to the two first photosensitive units 111 adjacent to the third photosensitive unit 113 in the vertical direction, and travels to the two fourth photosensitive units 114 adjacent to the third photosensitive unit 113 in the horizontal direction. i Blu-ray L B Most of the light travels to the four second photosensitive units 112 adjacent to the third photosensitive unit 113 in the diagonal direction.

[0133] By properly setting the thickness of the spacer layer 120, the above-mentioned color separation and convergence can be performed more effectively. For example, when the refractive index of the spacer layer 120 relative to the wavelength of λ0 is n and the pitch of the photosensitive unit is p, the theoretical thickness h of the spacer layer 120 is t The following Equation 1 may be satisfied.

[0134] [Equation 1]

[0135]

[0136] Here, the theoretical thickness h of the spacer layer 120 is t It may refer to the focal length of the dichroic lens array 130 for focusing the light having a wavelength of λ0 onto the top surfaces of the photosensitive units 111, 112, 113, and 114. In other words, the light having a wavelength of λ0 may be focused at a distance h from the bottom surface of the dichroic lens array 130 while passing through the dichroic lens array 130.t Place.

[0137] As described in Equation 1 above, the theoretical thickness h of the spacer layer 120 is t The thickness of the spacer layer 120 may vary depending on the pitch p of the photosensitive units 111, 112, 113, and 114 and the refractive index n of the spacer layer 120. For example, assuming that the center wavelength λ0 of the visible light band is 540 nm, the pitch p of the photosensitive units 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, the theoretical thickness h of the spacer layer 120 is t , that is, the optimal distance between the lower surface of the dichroic lens array 130 and the top surface of the sensor substrate 110 may be about 1.64 μm. However, the theoretical thickness of the spacer layer 120 is not necessarily limited to the theoretical thickness h described in Equation 1. t For example, considering the efficiency of the dichroic lens array 130, the theoretical thickness h can be calculated based on Equation 1. t The actual thickness of the spacer layer 120 is selected within a specific range.

[0138] Figures 10A to 10E is a graph showing a change in the efficiency of the dichroic lens array 130 according to the distance between the dichroic lens array 130 and the sensor substrate 110 when the pitch of each of the photosensitive units 111 , 112 , 113 , and 114 is 0.7 μm. Figure 10A FIG. 3 shows the focusing efficiency of the dichroic lens array 130 with respect to the blue light incident on the second photosensitive unit 112 from the first to fourth regions 131, 132, 133, and 134 constituting one unit pattern array of the dichroic lens array 130. Figure 10B shows the focusing efficiency of the dichroic lens array 130 with respect to the green light incident on the first photosensitive unit 111 and the fourth photosensitive unit 114 from the first area 131 to the fourth area 131 of one unit pattern array constituting the unit pattern array 130, and Figure 10C The condensing efficiency of the dichroic lens array 130 with respect to red light incident on the third photosensitive unit 113 from the first to fourth regions 131 , 132 , 133 , and 134 constituting one unit pattern array of the unit pattern array 130 is shown.

[0139] exist Figure 10A and Figure 10C In , since four areas are provided to one photosensitive unit, the theoretical maximum value is 4. Figure 10B In , since four areas are provided to two photosensitive units, the theoretical maximum value is 2. Figures 10A to 10C In the graph, the distance at which the focusing efficiency of the dichroic lens array 130 is the highest becomes the theoretical thickness h that satisfies Equation 1. t .like 10A to 10CAs shown, the theoretical thickness h t It varies slightly depending on the wavelength.

[0140] Figure 10D is a graph showing changes in the efficiency of a dichroic lens array taking into account the sensitivity characteristics of the human eye to visible light. For example, the human eye generally has the highest sensitivity to green light and the lowest sensitivity to blue light. Thus, according to example embodiments, the lowest weight may be assigned to Figure 10A , and the highest weight can be given to Figure 10B Furthermore, according to an exemplary embodiment, Figure 10C The curve of gives a higher weight than blue light. Figure 10A The curve graph gives the lowest weight to Figure 10C The curve graph gives a higher weight than blue light and Figure 10B Give the highest weight and average the sum to get Figure 10D 's curve graph. Figure 10E It shows the Figure 10D Graph of the normalized results.

[0141] Reference Figure 10D and Figure 10E According to the graph, when the pitch of each photosensitive unit 111, 112, 113, and 114 is 0.7 μm, the efficiency of the dichroic lens array 130 with respect to the entire visible light can be highest at a distance of approximately 1.2 μm, taking into account the sensitivity characteristics of the human eye. Furthermore, the efficiency of the dichroic lens array 130 can be approximately 80% of the maximum efficiency at a distance of approximately 0.5 μm, and approximately 95% of the maximum efficiency at a distance of approximately 1.9 μm.

[0142] Figures 11A to 11E 1 is a graph showing a change in the efficiency of the dichroic lens array 130 according to the distance between the dichroic lens array 130 and the sensor substrate 110 when the pitch of each photosensitive unit 111, 112, 113, and 114 is 0.8 μm. Figures 11A to 11E When the pitch of each photosensitive unit 111, 112, 113, and 114 is 0.8 μm, considering the sensitivity characteristics of the human eye, the efficiency of the dichroic lens array 130 relative to the entire visible light is highest at a distance of approximately 1.64 μm. Furthermore, the efficiency of the dichroic lens array 130 can be approximately 85% of the maximum efficiency at a distance of approximately 0.8 μm and approximately 93% of the maximum efficiency at a distance of approximately 2.5 μm.

[0143] 12A to 12E 1 is a graph showing a change in the efficiency of the dichroic lens array 130 according to the distance between the dichroic lens array 130 and the sensor substrate 110 when the pitch of each photosensitive unit 111, 112, 113, and 114 is 1.0 μm. 12A to 12E When the pitch of each photosensitive unit 111, 112, 113, and 114 is 1.0 μm, the efficiency of the dichroic lens array 130 relative to the entire visible light is highest at a distance of approximately 2.6 μm, taking into account the sensitivity characteristics of the human eye. Furthermore, the efficiency of the dichroic lens array 130 can be approximately 87% of the maximum efficiency at a distance of approximately 1.6 μm, and approximately 94% of the maximum efficiency at a distance of approximately 3.6 μm.

[0144] As a result, even if the actual thickness h of the spacer layer 120 is greater or less than the theoretical thickness h of the spacer layer 120 t The high efficiency of the color separation lens array 130 can be about 80%, 90%, or about 95% of the maximum efficiency. t -p≤h≤h t The actual thickness h of the spacer layer 120 is selected within the range of ρ + p.

[0145] Because the color separation lens array 130 can branch incident light according to wavelength without absorbing or blocking it, and can focus the branched light onto a specific area, it can improve the light utilization efficiency of the image sensor. Furthermore, because the color separation lens array 130 has improved color separation performance, an image sensor incorporating the color separation lens array 130 can have excellent color purity. Furthermore, because an image sensor incorporating the color separation lens array 130 can maintain the Bayer pattern commonly used in image sensors, it can utilize the same image processing algorithms as existing pixel structures. Furthermore, because the color separation lens array 130 serves as a lens for converging incident light, an image sensor incorporating the color separation lens array 130 does not require a separate microlens for focusing light onto each pixel.

[0146] Figure 13 is a perspective view illustrating exemplary shapes of nanorods that may be provided in a dichroic lens array according to example embodiments. Figure 13 , the nanopillar may have a cylindrical shape with a diameter D and a height H. The diameter D and the height H may have sub-wavelength values, and the diameter D may differ depending on the position where the nanopillar is arranged.

[0147] Furthermore, the nanopillars may have the shape of pillars of various cross-sectional shapes. 14A to 14H is a plan view of exemplary shapes of nanorods that may be provided in the dichroic lens array 130 of an image sensor.

[0148] like Figure 14AAs shown, the cross-sectional shape of the nanopillar can be a ring shape having an outer diameter D and an inner diameter Di. The width w of the ring can have a value of a sub-wavelength. The cross-sectional shape of the nanopillar can be an elliptical shape, in which the major axis length Dx and the minor axis length Dy are different from each other in the first direction (X direction) and the second direction (Y direction), as shown in FIG. Figure 14B As described in Figure 5B As mentioned in the embodiment of FIG. 1 , this shape may be provided in the first region 131 and the fourth region 134 corresponding to green pixels.

[0149] In addition, the cross-sectional shape of the nanopillars can be as follows Figure 14C 、 Figure 14D and Figure 14F The shape of the square, square ring or cross shown, or can be as shown Figure 14E and Figure 14G The rectangular shape or cross shape shown in FIG, wherein the lengths Dx and Dy are different from each other in the first direction (X direction) and the second direction (Y direction). Figure 5B As mentioned in the embodiment of FIG. 1 , a rectangular shape or a cross shape may be provided in the first region 131 and the fourth region 134 corresponding to the green pixel.

[0150] In another example, the cross-sectional shape of the nanorod may have a plurality of concave arc shapes, such as Figure 14H shown.

[0151] Figure 15 is a plan view illustrating an arrangement shape of nanorods constituting a dichroic lens array according to another example embodiment.

[0152] According to example embodiments, the dichroic lens array 140 may have Figure 2A The pixel arrangement of the Bayer pattern shown corresponds to a shape and may include 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 shown, the unit pattern array may be repeatedly arranged in a first direction (X direction) and a second direction (Y direction). Each region may be divided into a plurality of sub-regions, and the nanopillars NP may be arranged at the intersection of the boundaries between the plurality of sub-regions. Figure 15 The following example shows nine subregions, with nanopillars NP arranged at the lattice points that divide each region into nine subregions. Therefore, the nanopillar NP is not arranged at the center of each region 141, 142, 143, and 144. Instead, four nanopillars NP of the same size form the center. Nanopillars NP located at its periphery are arranged along the borders with other regions. Depending on the detailed position within the unit pattern array, r1 to r9 can indicate a nanopillar NP.

[0153] Reference Figure 15 , nanopillar r1 arranged at the center of the first region 141 corresponding to the green pixel may have a larger cross-sectional area than nanopillars r5, r6, and r9 arranged around the first region 141, and the cross-sectional area of ​​nanopillar r4 arranged at the center of the fourth region 144 corresponding to the green pixel may also be larger than the nanopillars r7, r8, and r9 arranged around the fourth region 144. The cross-sectional areas of nanopillars r1 and r4 arranged at the centers of the first region 141 and the fourth region 144 corresponding to the green pixel may be larger than the cross-sectional areas of nanopillar r2 arranged at the center of the second region 142 corresponding to the blue pixel and nanopillar r3 arranged at the center of the third region 143 corresponding to the red pixel. Furthermore, the cross-sectional area of ​​nanopillar r2 arranged at the center of the second region 142 corresponding to the blue pixel may be larger than the cross-sectional area of ​​nanopillar r3 arranged at the center of the third region 143 corresponding to the red pixel.

[0154] The nanopillars NP in the second region 142 and the third region 143 can be symmetrically arranged in the first direction (X direction) and the second direction (Y direction), and the nanopillars NP in the first region 141 and the fourth region 144 can be asymmetrically arranged in the first direction (X direction) and the second direction (Y direction). In other words, the nanopillars NP in the second region 142 and the third region 143 corresponding to the blue pixel and the red pixel, respectively, can have the same distribution pattern in the first direction (X direction) and the second direction (Y direction), and the nanopillars NP in the first region 141 and the fourth region 144 corresponding to the green pixel can have different distribution patterns in the first direction (X direction) and the second direction (Y direction).

[0155] Among the nanopillars NP, the cross-sectional area of ​​a nanopillar r5 located at the boundary between the first region 141 and the second region 142 adjacent to the first region 141 in the first direction (X direction) may be different from the cross-sectional area of ​​a nanopillar r6 located at the boundary between the first region 141 and the third region 143 adjacent to the first region 141 in the second direction (Y direction). In addition, the cross-sectional area of ​​a nanopillar r7 located at the boundary between the fourth region 144 and the third region 143 adjacent to the fourth region 144 in the first direction (X direction) may be different from the cross-sectional area of ​​a nanopillar r8 located at the boundary between the fourth region 144 and the second region 142 adjacent to the fourth region 144 in the second direction (Y direction).

[0156] On the other hand, the cross-sectional area of ​​the nanocolumn r5 located at the boundary between the first region 141 and the second region 142 adjacent to the first region 141 in the first direction (X direction) may be the same as that of the nanocolumn r8 located at the boundary between the fourth region 144 and the second region 142 adjacent to the fourth region 144 in the second direction (Y direction), and the cross-sectional area of ​​the nanocolumn r6 located at the boundary between the first region 141 and the third region 143 adjacent to the first region 141 in the second direction (Y direction) may be the same as that of the nanocolumn r7 located at the boundary between the fourth region 144 and the third region 143 adjacent to the fourth region 144 in the first direction (X direction).

[0157] Also, the nano-pillars r9 arranged at four edges of each of the first, second, third, and fourth regions 141, 142, 143, and 144 (ie, where the four regions cross each other) may have the same cross-sectional area.

[0158] In this way, the nanopillars NP can be arranged in the second region 142 and the third region 143 corresponding to the blue pixel and the red pixel, respectively, in a 4-fold symmetric form, and the nanopillars NP can be arranged in the first region 141 and the fourth region 144 corresponding to the green pixel in a 2-fold symmetric form, and the first region 141 and the fourth region 144 can be rotated 90 degrees relative to each other. These shapes are described later. Figure 16 and Figure 17 is shown in the embodiment of FIG.

[0159] Figure 16 is a plan view illustrating an arrangement shape of nanorods constituting a dichroic lens array according to another example embodiment.

[0160] According to example embodiments, the dichroic lens array 150 may have a shape corresponding to a pixel arrangement of a Bayer pattern and may include a first region 151 corresponding to a green pixel, a second region 152 corresponding to a blue pixel, a third region 153 corresponding to a red pixel, and a fourth region 154 corresponding to a green pixel. Each region may be divided into a plurality of sub-regions, and the nanopillars NP may be arranged at intersections of boundaries between the plurality of sub-regions. Figure 16 An example is shown where the number of sub-regions is 16, so Figure 16 and Figure 15 The nanopillars are arranged differently. Nanopillars NP are arranged on lattice points that divide each region into 16 subregions, so that the nanopillars NP can be arranged at the center of each of regions 151, 152, 153, and 154. According to the detailed position within the unit pattern array, s1 to s11 indicate the nanopillars NP.

[0161] exist Figure 16 In the embodiment, the nanopillar s1 located at the center of the first region 151 corresponding to the green pixel and the nanopillar s4 located at the center of the fourth region 154 may have a cross-sectional area greater than that of the nanopillars NP arranged in the second region 152 corresponding to the blue pixel and in the third region 153 corresponding to the red pixel, as well as the nanopillars NP located around them.

[0162] In the first region 151, the nanopillar s1 having the largest cross-sectional area can be arranged at the center, while the nanopillars s10, s5, and s6 can be arranged with cross-sectional areas gradually decreasing toward the periphery. Even in the fourth region 154, the nanopillar s4 having the largest cross-sectional area can be arranged at the center, while the nanopillars s11, s7, and s8 can be arranged with cross-sectional areas gradually decreasing toward the periphery. In contrast, in the second region 152, nine nanopillars s2 having the same cross-sectional area can be arranged at the center, while nanopillars s5 and s8 having larger cross-sectional areas than nanopillars s2 can be arranged at the periphery. Even in the third region 153, nine nanopillars s3 having the same cross-sectional area can be arranged at the center, while nanopillars s6 and s7 having larger cross-sectional areas than nanopillars s3 can be arranged at the periphery. In both the second and third regions 152 and 153, the nanopillars NP located at the periphery are arranged on the borders with other regions.

[0163] exist Figure 16 In the embodiment, Figure 15 As in the embodiment of the present invention, the nanopillars NP in the second region 152 and the third region 153 can be symmetrically arranged in the first direction (X direction) and the second direction (Y direction), and the nanopillars NP in the first region 151 and the fourth region 154 can be asymmetrically arranged in the first direction (X direction) and the second direction (Y direction). Moreover, the nanopillars s9 arranged at the four edges of each of the first region 151, the second region 152, the third region 153, and the fourth region 154 (i.e., the four regions are adjacent to each other) can have the same cross-sectional area.

[0164] Figure 17 is a plan view illustrating an arrangement shape of nanorods constituting a dichroic lens array according to another example embodiment.

[0165] According to example embodiments, the dichroic lens array 160 may have a shape corresponding to a pixel arrangement of a Bayer pattern and may include a first region 161 corresponding to a green pixel, a second region 162 corresponding to a blue pixel, a third region 163 corresponding to a red pixel, and a fourth region 164 corresponding to a green pixel. Each region may be divided into a plurality of sub-regions, and the nanorods NP may be arranged in the plurality of sub-regions. In the dichroic lens array 160, as shown in FIG. Figure 15 As shown, each region can be divided into nine sub-regions, but the difference is that the nanopillars NP are arranged inside the sub-regions rather than at the intersections between the sub-regions. According to the detailed position within the unit pattern array, t1 to t16 indicate the nanopillars NP.

[0166] according to Figure 17 In an exemplary embodiment, nanopillar t1 located at the center of first region 161 and nanopillar t4 located at the center of fourth region 164 may have larger cross-sectional areas than nanopillars NP arranged in second region 162 and third region 163, and nanopillars NP located at the periphery of first region 161 and fourth region 164. The cross-sectional area of ​​nanopillar t2 located at the center of second region 162 may be larger than the cross-sectional area of ​​nanopillar t3 located at the center of third region 163. In second region 162, nanopillars t6 and t10 located at the periphery and spaced from the center in the first direction (X direction) and the second direction (Y direction) may have larger cross-sectional areas than nanopillar t2 located at the center. In contrast, nanopillar t14 located at the periphery and spaced diagonally from the center may have smaller cross-sectional areas than nanopillar t2 located at the center. In third region 163, nanopillar t3 located at the center may have the smallest cross-sectional area, and all nanopillars t7, t11, and t15 located at the periphery may have larger cross-sectional areas than nanopillar t3 located at the center.

[0167] The nanopillars NP in the second region 162 and the third region 163 can be symmetrically arranged in the first direction (X direction) and the second direction (Y direction), and the nanopillars NP in the first region 161 and the fourth region 164 can be asymmetrically arranged in the first direction (X direction) and the second direction (Y direction). In other words, the nanopillars NP in the second region 162 and the third region 163 corresponding to the blue pixel and the red pixel, respectively, can exhibit the same distribution pattern in the first direction (X direction) and the second direction (Y direction), while the nanopillars NP in the first region 161 and the fourth region 164 corresponding to the green pixel can exhibit different distribution patterns in the first direction (X direction) and the second direction (Y direction).

[0168] In the first region 161, the central nanopillar t1, the nanopillar t5 adjacent to the first region 161 in the first direction (X direction), and the nanopillar t9 adjacent to the first region 161 in the second direction (Y direction) may have different cross-sectional areas. Even in the fourth region 164, the central nanopillar t4, the nanopillar t8 adjacent to the fourth region 164 in the first direction (X direction), and the nanopillar t12 adjacent to the fourth region 164 in the second direction (Y direction) may have different cross-sectional areas. In this case, the nanopillar t1 at the center of the first region 161 and the nanopillar t5 adjacent to the first region 161 in the first direction (X direction) may have the same cross-sectional area as the nanopillar t4 at the center of the fourth region 164 and the nanopillar t12 adjacent to the fourth region 164 in the second direction (Y direction), and the nanopillar t11 at the center of the first region 161 and the nanopillar t9 adjacent to the first region 161 in the second direction (Y direction) may have the same cross-sectional area as the nanopillar t4 at the center of the fourth region 164 and the nanopillar t8 adjacent to the fourth region 164 in the first direction (X direction). The nanopillar t13 adjacent to the four edges of the first region 161 may have the same cross-sectional area as the nanopillar t16 adjacent to the four edges of the fourth region 164. Therefore, the first region 161 and the fourth region 164 may be rotated 90 degrees relative to each other.

[0169] The nanopillar t6 at the center of the second region 162, the nanopillar t6 adjacent to the second region 162 in the first direction (X direction), and the nanopillar t10 adjacent to the second region 162 in the second direction (Y direction) may have the same cross-sectional area. The nanopillars t14 adjacent to the four edges of the second region 162 may also have the same cross-sectional area.

[0170] Even in the third region 163, the central nanopillar t3, the nanopillar t7 adjacent to the third region 163 in the first direction (X direction), and the nanopillar t11 adjacent to the third region 163 in the second direction (Y direction) may have the same cross-sectional area. The nanopillars t15 adjacent to the four edges of the third region 163 may have the same cross-sectional area.

[0171] Figure 18 is a plan view illustrating an arrangement shape of a plurality of nanorods constituting a dichroic lens array according to another example embodiment.

[0172] According to an example embodiment, Figure 18The simplest structure is shown in the dichroic lens array 170. One nanopillar NP can be arranged in each of the first region 171 corresponding to the green pixel, the second region 172 corresponding to the blue pixel, the third region 173 corresponding to the red pixel, and the fourth region 174 corresponding to the green pixel. The cross-sectional area of ​​the nanopillars NP in the first region 171 and the fourth region 174 can be the largest, the cross-sectional area of ​​the nanopillars NP in the second region 172 can be smaller than that of the nanopillars NP in the first region 171, and the cross-sectional area of ​​the nanopillars NP in the third region 173 can be the smallest.

[0173] Figure 19 It shows the incident Figure 18 FIG. 1 is a graph showing the spectral distribution of light on each of the red pixel R, green pixel G, and blue pixel B of the image sensor including the dichroic lens array.

[0174] Figure 20A and Figure 20B is a cross-sectional view of a schematic structure of a pixel array according to another exemplary embodiment. Figure 4A and Figure 4B The difference of the above exemplary embodiment is that a color filter 105 is further provided between the sensor substrate 110 and the color separation lens array 130. The color filter 105 may be arranged between the sensor substrate 110 and the spacer layer 120. Specifically, Figure 20A is a cross-sectional view of a schematic structure of a first row of a pixel array, and Figure 20B is a cross-sectional view showing a schematic structure of the second row of the pixel array.

[0175] The pixel array 1100a may further include a transparent dielectric layer 121 that protects the dichroic lens array 130. The dielectric layer 121 may be arranged to cover adjacent nanopillars NP and the space between the top surfaces of the nanopillars NP. The dielectric layer 121 may be made of a material having a lower refractive index than that of the nanopillars NP, for example, the same material as the spacer layer 120.

[0176] The color filter 105 may include a filter area having a shape corresponding to the pixel arrangement in the Bayer pattern. Figure 20A As shown, the green filter regions CF1 and the blue filter regions CF2 may be alternately arranged, and as shown in FIG. Figure 20BAs shown, in the next row spaced apart in the Y direction, red filter regions CF3 and green filter regions CF1 can be arranged alternately. Because the dichroic lens array 130 branches and converges light having different wavelengths onto the multiple photosensitive cells 111, 112, 113, and 114, the configuration of the color filter 105 is not a necessary component. However, in this manner, the color filter 105 can be additionally provided to enhance color purity, and since the separated light largely enters the color filter 105, light loss is minimal.

[0177] Figure 21 is a graph showing spectral distribution of light incident on a red pixel R, a green pixel G, and a blue pixel B of an image sensor of an embodiment provided with a color filter, and Figure 22 : is a graph showing the spectral distribution of light incident on the red pixel R, the green pixel G, and the blue pixel B of the image sensor of the embodiment in which no color filter is provided.

[0178] Figure 21 The graph includes Figure 20A and 20B The color filters of the image sensor are shown, and Figure 22 The graph is not Figure 4A and 4B The spectrum of the image sensor with the color filters shown. Figure 21 and Figure 22 The simulation results of an image with a pixel width of about 0.7 μm are shown, and when the color filter is provided, the total amount of light tends to decrease, but both show good color separation performance.

[0179] Figure 23 FIG is a plan view showing a dichroic lens array according to another exemplary embodiment. Figure 23 , the color separation lens array 340 may include a plurality of unit pattern arrays represented by bold lines. Each unit pattern array may be arranged in a two-dimensional form of 2×2, including a first region 341, a second region 342, a third region 343, and a fourth region 344. When describing the overall configuration of the color separation lens array 340, the first region 341 and the second region 342 may be alternately arranged in a row in the horizontal direction, and the third region 343 and the fourth region 344 may be alternately arranged in another row in the horizontal direction. In addition, the first region 341 and the third region 343 may be alternately arranged in a column in the vertical direction, and a plurality of second regions 342 and a plurality of fourth regions 344 may be alternately arranged in another column in the vertical direction.

[0180] Furthermore, the dichroic lens array 340 may further include a plurality of first to fourth regions 341, 342, 343, and 344 that do not belong to any unit pattern array. The first to fourth regions 341, 342, 343, and 344 that do not belong to any unit pattern array may be arranged along the edge of the dichroic lens array 340. In other words, the plurality of second regions 342 and the plurality of fourth regions 344 forming a column may be additionally arranged on the left edge of the dichroic lens array 340, the plurality of first regions 341 and the plurality of third regions 343 forming a column may be additionally arranged on the right edge of the dichroic lens array 340, the plurality of third regions 343 and the plurality of fourth regions 344 forming a row may be additionally arranged on the upper edge of the dichroic lens array 340, and the plurality of first regions 341 and the plurality of second regions 342 forming a row may be additionally arranged on the lower edge of the dichroic lens array 340.

[0181] Figure 24 It is taken along line C-C' Figure 23 The vertical cross section of the dichroic lens array 340 is shown. Figure 24 The dichroic lens array 340 may include a plurality of first regions 341 and a plurality of second regions 342 that protrude in the horizontal direction relative to the edge of the sensor substrate 110 and do not face any photosensitive unit of the sensor substrate 110 in the vertical direction. Figure 24 Not all are shown, but Figure 23 In the embodiment, all of the plurality of first to fourth regions 341, 342, 343, and 344 that do not belong to any unit pattern array may protrude in a horizontal direction relative to an edge of the sensor substrate 100 and may not face any photosensitive unit in a vertical direction.

[0182] like 6A to 6D 、 7A to 7D as well as Figures 8A to 8D As described above, the photosensitive cells receive light not only from the area corresponding to the vertical direction of the dichroic lens array 340, but also from multiple other areas surrounding that area. Therefore, if the first to fourth areas 341, 342, 343, and 344 added along the edge of the dichroic lens array 340 are not present, the amount of light incident on the photosensitive cells arranged along the edge of the sensor substrate 110 can be reduced, and the color purity can also be reduced. The first to fourth areas 341, 342, 343, and 344 can be additionally arranged along the edge of the dichroic lens array 340, allowing the photosensitive cells arranged along the edge of the sensor substrate 110 to be arranged in the same manner as the photosensitive cells arranged within the sensor substrate 110. Figure 23 and Figure 24 The illustrated embodiment can also be applied to the dichroic lens arrays 130 , 140 , 150 , 160 , and 170 described above.

[0183] Figure 25 is a cross-sectional view showing a schematic structure of a pixel array according to another example embodiment, and Figure 26 It is shown in Figure 25 Perspective view of exemplary shapes of nanopillar NPs employed in a dichroic lens array.

[0184] Pixel array 1100b includes a sensor substrate 310 for sensing light and a dichroic lens array 350 disposed on sensor substrate 310. A spacer layer 320 is disposed between sensor substrate 310 and dichroic lens array 350. Dichroic lens array 350 may include a plurality of nanopillars NP supported by spacer layer 320 and arranged according to a specific pattern. Sensor substrate 310 may include a plurality of photosensitive cells for sensing light, which may correspond one-to-one with the plurality of regions of dichroic lens array 350. For convenience, the illustration of such regional divisions is omitted.

[0185] The dichroic lens array 350 according to example embodiments is different from the above-described example embodiments in that each of the plurality of nanopillars NP includes a lower pillar LP and an upper pillar UP stacked on the lower pillar LP.

[0186] According to example embodiments, a portion of the plurality of nanopillars NP may have a shape in which a lower pillar LP and an upper pillar UP are stacked so as to be shifted from each other. Figure 26 The upper pillar UP deviates from the lower pillar LP in a direction from the central portion C toward the peripheral portion P.

[0187] In order to manufacture nanopillars NP having such a structure, a first material layer 331 filling the area between the lower pillars LP and supporting the upper pillars UP, and a second material layer 332 covering the upper pillars UP may be further provided. The first material layer 331 and the second material layer 332 may be formed of a material having a refractive index lower than that of the material used to form the upper pillars UP and the lower pillars LP.

[0188] This arrangement takes into account the different light incident angles at the peripheral portion P and the central portion C of the pixel array 1100b employed in the image capture device. Generally, light is vertically incident near the central portion C of the pixel array 1100b, and the incident angle increases toward the peripheral portion P. Nanopillars NP can be configured in a shape corresponding to this incident path, making it easier to produce the desired color separation even for oblique light incident on the image sensor 302.

[0189] Although the nanopillars NP show a structure in which they are stacked in two layers, upper and lower layers, the nanopillars NP may have a structure of three or more layers, and the shapes or sizes of the nanopillars of the upper and lower layers may vary depending on positions. Figure 25 and Figure 26 The illustrated embodiment can also be applied to the dichroic lens arrays 130 , 140 , 150 , 160 , 170 , and 340 described above.

[0190] although Figure 25 The nanopillars NP shown have a structure in which some nanopillars NP are stacked without bias and some nanopillars NP are stacked with bias, but the present disclosure is not limited thereto. For example, according to example embodiments, all nanopillars NP in a pixel array may be stacked without bias, or all nanopillars NP in a pixel array may be stacked with bias.

[0191] According to the above-described example embodiments, since the light loss caused by the color filter is very small, even if the size of the pixel is reduced, a sufficient amount of light can be effectively provided to the pixel. Therefore, it is possible to manufacture ultra-high-resolution, ultra-small, and highly sensitive image sensors having hundreds of millions of pixels or more. Such ultra-high-resolution, ultra-small, and highly sensitive image sensors can be used in various high-performance optical devices or high-performance electronic devices. Such electronic devices may include, for example, smartphones, mobile phones, personal digital assistants (PDAs), laptop computers, personal computers (PCs), various portable devices, electronic devices, surveillance cameras, medical cameras, automobiles, Internet of Things (IoT) devices, and other mobile or non-mobile computing devices, but are not limited thereto.

[0192] Figure 27 2 is a block diagram schematically illustrating an electronic device including an image sensor according to an embodiment. The electronic device may include an image sensor 1000, a processor 2200, a memory 2300, a display 2400, and a bus 2500. The image sensor 1000 may acquire image information about an external object under the control of the processor 2200 and may provide the image information to the processor 2200. The processor 2200 may store the image information provided from the image sensor 1000 in the memory 2300 via the bus 2500 and may output the image information stored in the memory 2300 to the display device 2400 to display the image information to the user. In addition, the processor 2200 may perform various image processing on the image information provided from the image sensor 1000.

[0193] Figures 28 to 38 Various examples of multimedia electronic devices to which the image sensor according to one or more example embodiments is applied are illustrated.

[0194] According to one or more example embodiments, the image sensor shown in the present disclosure may be applied to various electronic devices having an image capturing function. For example, the image sensor may be applied to Figure 28 The camera 2000 is shown. The camera 2000 may be a digital still camera or a digital video camera.

[0195] Reference Figure 29 , the camera 2000 may include an image capturing unit 2100 , an image sensor 1000 , and a processor 2200 .

[0196] The image capture unit 2100 can focus the light reflected from the object OBJ to form an optical image. The image capture unit 2100 may include an objective lens 2010, a lens driver 2120, an aperture 2130, and an aperture driver 2140. Although the image capture unit 2100 is not shown in FIG. Figure 29 Only one lens is representatively shown in the figure, but the present disclosure is not limited thereto. However, according to other example embodiments, the objective lens 2010 may include a plurality of lenses having different sizes and shapes. The lens driver 2120 may communicate information about focus detection with the processor 2200, and may adjust the position of the objective lens 2010 according to a control signal provided by the processor 2200. The lens driver 1120 may move the objective lens 2010 to adjust the distance between the objective lens 2010 and the object OBJ, or to adjust the position of each lens in the objective lens 2010. The lens driver 2120 may drive the objective lens 2010 so as to adjust the focus on the object OBJ. The camera 2000 may have an autofocus (AF) function.

[0197] The aperture iris driver 2140 may communicate information about the amount of light with the processor 2200 and may adjust the aperture iris 2130 according to a control signal provided by the processor 2200. For example, the aperture iris driver 2140 may increase or decrease the aperture of the aperture iris 2130 according to the amount of light entering the camera 2000 through the objective lens 2010 and may adjust the opening time of the aperture iris 2130.

[0198] The image sensor 1000 may generate an electrical image signal based on the intensity of incident light. The image sensor 1000 may include a pixel array 1100, a timing controller 1010, and an output circuit 1030. According to example embodiments, the image sensor 1000 may further include Figure 1The row decoder shown. Light projected through objective lens 2010 and aperture diaphragm 2130 can form an image of object OBJ on the light receiving surface of pixel array 1100. Pixel array 1100 can be a CCD or CMOS that converts optical signals into electrical signals. Pixel array 1100 can include additional pixels for performing an AF function or a distance measurement function. Furthermore, pixel array 1100 can include the aforementioned dichroic lens array.

[0199] The processor 2200 may control the overall operation of the camera 2000 and may have an image processing function. For example, the processor 2200 may provide a control signal for the operation of each component to the lens driving unit 2120, the aperture driver 2140, and the timing controller 1010.

[0200] The image sensor according to example embodiments may be applied to Figure 30 The mobile phone or smart phone 3000 shown, Figure 31 The tablet computer or smart tablet computer 3100 shown, Figure 32 Laptop computer 3200 or Figure 33 The television or smart TV 3300 is shown. For example, the smartphone 3000 or the smart tablet computer 3100 may include multiple high-resolution cameras, each equipped with a high-resolution image sensor. The high-resolution cameras can be used to extract depth information about objects in an image, adjust the defocusing of an image, or automatically identify objects in an image.

[0201] Moreover, image sensors can be applied to Figure 34 The smart refrigerator 3400 shown, Figure 35 The camera 3500 shown, Figure 36 The robot 3600 shown and Figure 35 Medical camera 3700 is shown. For example, smart refrigerator 3400 can use image sensors to automatically identify food in the refrigerator and notify the user via smartphone of the presence of specific food, the type of food that has been placed or released, etc. Camera 3500 can be a security camera or surveillance camera that can provide ultra-high-resolution images and use high sensitivity to identify objects or people in the image even in dark environments. Robot 3600 can be input from disaster or industrial sites that cannot be directly accessed by humans and can provide high-resolution images. Medical camera 3700 can provide high-resolution images for diagnosis or surgery and can dynamically adjust the field of view.

[0202] Moreover, the image sensor can be Figure 383800. Vehicle 3800 may include multiple vehicle cameras 3810, 3820, 3830, and 3840 arranged at various locations. Each of the multiple vehicle cameras 3810, 3820, 3830, and 3840 may include an image sensor according to an example embodiment. Vehicle 3800 may use multiple vehicle cameras 3810, 3820, 3830, and 3840 to provide the driver with various information about the interior or surrounding environment of vehicle 3800, and may automatically identify objects or people in the image to provide information necessary for autonomous driving.

[0203] Because the disclosed dichroic lens array can separate and focus light of each wavelength without absorbing or blocking incident light, it can improve the light utilization efficiency of image sensors. Furthermore, image sensors employing the disclosed dichroic lens array can maintain the Bayer pattern commonly used in image sensors, thereby utilizing the pixel structure and image processing algorithms of existing image sensors. Furthermore, image sensors employing the disclosed dichroic lens array do not require separate microlenses for focusing light onto pixels.

[0204] Although the image sensor including the above-described dichroic lens array and the electronic device including the image sensor have been described with reference to the example embodiments shown in the accompanying drawings, the present disclosure is not limited thereto, and those skilled in the art will appreciate that variations and other equivalent embodiments are possible. Therefore, the example embodiments should be considered merely as illustrative and not for purposes of limitation. The scope of the claims is indicated in the claims, not in the foregoing description, and all differences within the scope of the claims should be construed as being included within the scope of the claims.

[0205] It should be understood that the example embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. The description of features or aspects in each example embodiment should typically be considered as applicable to other similar features or aspects in other example embodiments. Although one or more example embodiments have been described with reference to the accompanying drawings, it should be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the appended claims.

Claims

1. An image sensor, comprising: a sensor substrate comprising a first photosensitive unit and a second photosensitive unit configured to sense light; A dichroic lens array comprising a first region and a second region, wherein the first region faces the first photosensitive unit and comprises at least one first nanorod, and the second region faces the second photosensitive unit and comprises at least one second nanorod; and a spacer layer disposed between the sensor substrate and the dichroic lens array, such that the first nanorods and the second nanorods are disposed on a top surface of the spacer layer; wherein at least one of a first size, a first shape, or a first arrangement of the first nanorods is different from at least one of a second size, a second shape, or a second arrangement of the second nanorods, and In which, the first nanocolumn and the second nanocolumn are configured so that light with a first wavelength and light with a second wavelength, which are different from each other in the incident light incident on the color separation lens array, are branched into different directions, and the light with the first wavelength converges onto the first photosensitive unit, and the light with the second wavelength converges onto the second photosensitive unit.

2. The image sensor according to claim 1, wherein For light of the first wavelength, the first nanopillar and the second nanopillar are formed at a position immediately after the light passes through the color separation lens array: a phase distribution of 2Nπ at a position corresponding to the center of the first photosensitive unit, a phase distribution of (2N-1)π at a position corresponding to the center of the second photosensitive unit, and N is an integer greater than 0.

3. The image sensor according to claim 2, wherein: For light of the second wavelength, the first nanorod and the second nanorod are formed at a position immediately after the light passes through the color separation lens array: a phase distribution of (2M-1)π at a position corresponding to the center of the first photosensitive unit, a phase distribution of 2Mπ at a position corresponding to the center of the second photosensitive unit, and M is an integer greater than 0.

4. The image sensor according to claim 1, wherein The thickness of the spacer layer corresponds to the focal length of the dichroic lens array with respect to the center wavelength of a wavelength band of incident light to be separated by the dichroic lens array.

5. The image sensor according to claim 1, wherein When the theoretical thickness of the spacer layer is h t , the spacing between each photosensitive unit is p, the refractive index of the spacer layer is n, and the central wavelength of the wavelength band of light to be separated by the color separation lens array is λ0, the theoretical thickness of the spacer layer is h t It is expressed by the following equation: ,as well as The actual thickness h of the spacer layer is h t -p≤h≤h t +p range to select.

6. The image sensor according to claim 1, wherein The sensor substrate further includes a third photosensitive unit and a fourth photosensitive unit configured to sense light, and The dichroic lens array further includes a third region and a fourth region, wherein the third region faces the third photosensitive unit and includes a third nanorod, and the fourth region faces the fourth photosensitive unit and includes a fourth nanorod, and At least one of a third size, a third shape, or a third arrangement of the third nanorod is different from at least one of a fourth size, a fourth shape, or a fourth arrangement of the fourth nanorod.

7. The image sensor according to claim 6, wherein: The first to fourth nanopillars form a phase distribution at the position where light passes through the first region to the fourth region. Through the phase distribution, light with a first wavelength, light with a second wavelength, and light with a third wavelength, which are different from each other in the incident light incident on the color separation lens array, are branched to different directions, the light with the first wavelength is converged onto the first photosensitive unit and the fourth photosensitive unit, the light with the second wavelength is converged onto the second photosensitive unit, and the light with the third wavelength is converged onto the third photosensitive unit.

8. The image sensor according to claim 7, wherein: The light having the first wavelength is green light, the light having the second wavelength is blue light, and the light having the third wavelength is red light.

9. The image sensor according to claim 7, wherein: For light of the first wavelength, the first to fourth nanocolumns are formed at positions immediately after the light passes through the color separation lens array: a phase distribution of 2Nπ at positions corresponding to the center of the first photosensitive unit and the center of the fourth photosensitive unit, a phase distribution of (2N-1)π at positions corresponding to the center of the second photosensitive unit and the center of the third photosensitive unit, and N is an integer greater than 0.

10. The image sensor according to claim 9, wherein: For light of the second wavelength, the first to fourth nanocolumns are formed at positions immediately after the light passes through the color separation lens array: a phase distribution of (2M-1)π at positions corresponding to the center of the first photosensitive unit and the center of the fourth photosensitive unit, a phase distribution of 2Mπ at a position corresponding to the center of the second photosensitive unit, a phase distribution greater than (2M-2)π and less than (2M-1)π at a position corresponding to the center of the third photosensitive unit, and M is an integer greater than 0.

11. The image sensor according to claim 10, wherein: For the light of the third wavelength, the first to fourth nanocolumns are formed at positions immediately after the light passes through the color separation lens array: a phase distribution of (2L-1)π at positions corresponding to the center of the first photosensitive unit and the center of the fourth photosensitive unit, a phase distribution of 2Lπ at a position corresponding to the center of the third photosensitive unit, a phase distribution greater than (2L-2)π and less than (2L-1)π at a position corresponding to the center of the second photosensitive unit, and L is an integer greater than 0.

12. The image sensor according to claim 9, wherein: The image sensor has a pixel arrangement structure in which a plurality of unit pixels including red pixels, green pixels, and blue pixels are arranged in a Bayer pattern, and Among the first to fourth nanocolumns, the nanocolumns in the first to fourth regions corresponding to the green pixels have different distribution rules in a first direction and a second direction perpendicular to the first direction.

13. The image sensor according to claim 12, wherein: Among the first to fourth nanocolumns, the nanocolumns in the first to fourth regions corresponding to the blue pixels and the red pixels have a symmetrical distribution rule in the first direction and the second direction.

14. The image sensor according to claim 12, wherein: One of the first to fourth nanocolumns located at the center of an area corresponding to the green pixel among the first to fourth areas has a larger cross-sectional area than another of the first to fourth nanocolumns located in an area corresponding to a pixel of another color.

15. The image sensor according to claim 12, wherein: In an area corresponding to the green pixel among the first to fourth areas, one of the first to fourth nanopillars located at the center of the area has a larger cross-sectional area than another nanopillar among the first to fourth nanopillars located at the periphery of the area.

16. The image sensor according to claim 1, wherein The dichroic lens array further includes a plurality of first regions and a plurality of second regions, which are arranged to protrude from an edge of the sensor substrate and not face any photosensitive unit of the sensor substrate in a vertical direction.

17. The image sensor according to claim 1, wherein At least one of the first nanopillar and the second nanopillar includes a lower pillar and an upper pillar stacked on the lower pillar, and wherein the lower column and the upper column are stacked to be offset from each other.

18. The image sensor according to claim 17, wherein: The degree of offset between the lower pillar and the upper pillar increases from a central portion to a peripheral portion of the image sensor.

19. An image sensor comprising: a sensor substrate comprising a plurality of first photosensitive cells and a plurality of second photosensitive cells arranged alternately along a first row, and a plurality of third photosensitive cells and a plurality of fourth photosensitive cells arranged alternately along a second row adjacent to the first row; The color separation lens array includes: a plurality of first regions, each facing the plurality of first photosensitive units and including at least one first nanorod; a plurality of second regions, each facing the plurality of second photosensitive units and including at least one second nanorod; a plurality of third regions, each facing the plurality of third photosensitive units and including at least one third nanorod; and a plurality of fourth regions, each facing the plurality of fourth photosensitive units and including at least one fourth nanorod; and a spacer layer disposed between the sensor substrate and the dichroic lens array, such that the first nanopillar, the second nanopillar, the third nanopillar, and the fourth nanopillar are disposed on a top surface of the spacer layer; Wherein, at least one of the shape, size and arrangement of the first to fourth nanopillars is configured as follows: For light incident on the first area, light with a first wavelength is focused on the first photosensitive unit located directly below the first area, light with a second wavelength is branched to the second photosensitive unit adjacent to the first photosensitive unit in the horizontal direction, and light with a third wavelength is branched to the third photosensitive unit adjacent to the first photosensitive unit in the vertical direction, and For light incident in the second area, light with the second wavelength is converged onto the second photosensitive unit located directly below the second area, light with the first wavelength is branched to the first photosensitive unit adjacent to the second photosensitive unit in the horizontal direction and to the fourth photosensitive unit adjacent to the second photosensitive unit in the vertical direction, and light with the third wavelength is branched to the third photosensitive unit adjacent to the second photosensitive unit in the diagonal direction.

20. The image sensor according to claim 19, wherein The light having the first wavelength is green light, the light having the second wavelength is blue light, and the light having the third wavelength is red light.

21. The image sensor according to claim 19, wherein The first nanopillars and the fourth nanopillars are arranged in a 2-fold symmetric form, the first region and the fourth region are rotated 90 degrees relative to each other, and the second nanopillars and the third nanopillars are arranged in a 4-fold symmetric form.

22. An electronic device comprising: an image capturing unit configured to focus light reflected from an object and form an optical image; as well as The image sensor according to claim 1, configured to convert an optical image formed by the image capturing unit into an electrical signal.

23. The electronic device according to claim 22, wherein: The electronic device includes a smartphone, a mobile phone, a personal digital assistant (PDA), a laptop computer, a personal computer (PC), a home appliance, a security camera, a medical camera, a vehicle, or an Internet of Things (IoT) device.

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