Image device and manufacturing method thereof

Abstract

SOLUTION: An image device 100 includes multiple photodiodes 116, a color filter layer 130, and a metasurface layer 150, in which the color filter layer is located on the multiple photodiodes and includes a blue filter B, a red filter, a first green filter G1, and a second green filter G2, the metasurface layer is located on the color filter layer and includes a first pixel unit, which includes a blue region BR on the blue filter, a red region on the red filter, a first green region GR1 on the first green filter, and a second green region on the second green filter G3, and the first green region is offset from a center point GR1_C of the first green region by a first vertical shift in the Y-axis direction and a first horizontal shift in the X-axis direction of a first central nanopost 154B when viewed from above.EFFECT: The performance of an image device is enhanced.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD The present disclosure relates to imaging devices and methods for manufacturing imaging devices. [Background technology]

[0002] In a complementary metal-oxide semiconductor (CMOS) image sensor (also known as CIS), a light-receiving component, such as a microlens layer or metasurface layer, may have the function of receiving and separating incident light containing different wavelengths of different colors. A color filter layer is placed below the light-receiving component and acts as an absorber to absorb light of a specific wavelength band before it propagates to the photodiode. The color separation of light in an imaging device further affects the performance of the imaging device.

[0003] However, the design of the metasurface layer, such as the color filter pattern in the color filter layer and the arrangement and shape of the nanostructures in the metasurface layer, can have a significant impact on the color distribution of light, so it is necessary to design the metasurface layer to improve the performance of the imaging device. Summary of the Invention

[0004] One aspect of the present disclosure provides an imaging device. The imaging device includes a plurality of photodiodes, a color filter layer, and a metasurface layer. The color filter is located on the plurality of photodiodes, and the color filter layer includes a blue filter, a red filter, a first green filter, and a second green filter. The metasurface layer is located on the color filter layer and includes a first pixel unit, the first pixel unit including a blue region on the blue filter, a red region on the red filter, a first green region on the first green filter, and a second green region on the second green filter. The first green region includes a first central nanopost, which is offset from the center of the first green region by a first vertical shift of the first central nanopost in the Y-axis direction and a first horizontal shift of the first central nanopost in the X-axis direction, as viewed from above. The second green region includes a second central nanopost, which is offset from the center of the second green region by a second vertical shift of the second central nanopost in the Y-axis direction and a second horizontal shift of the second central nanopost in the X-axis direction, as viewed from above.

[0005] In some embodiments, the first vertical shift and the first horizontal shift are determined by an angle of incidence and an azimuthal angle of the first green region. The angle of incidence of the first green region is between a first light incident on a top surface of the first green region and a normal to the top surface of the first green region. The azimuthal angle of the first green region is between a horizontal axis of the metasurface layer passing through a center of the metasurface layer and a first connecting line between the center of the first green region and the center of the metasurface layer.

[0006] In some embodiments, the metasurface layer further includes a second pixel unit, the second pixel unit including a third green region, the third green region including a third central nanopost, the third central nanopost being offset from the center of the third green region by a third vertical shift in the Y-axis direction of the third central nanopost and a third horizontal shift in the X-axis direction of the third central nanopost when viewed from above, the third vertical shift and the third horizontal shift being determined according to the angle of incidence and the azimuthal angle of the third green region. The angle of incidence of the third green region is between a second incident light on a top surface of the third green region and a normal to the top surface of the third green region. The azimuthal angle of the third green region is between the horizontal axis of the metasurface layer passing through the center of the metasurface layer and a second connecting line between the center of the third green region and the center of the metasurface layer. The first vertical shift of the first central nanopost and the third vertical shift of the third central nanopost satisfy the following equation:

number

[0007] In some embodiments, the first horizontal shift of the first central nanopost and the third horizontal shift of the third central nanopost satisfy the following formula:

number

[0008] In some embodiments, an edge of the first green region is offset from an edge of the corresponding first green filter by the first green region offset distance, the color filter layer includes a third green filter adjacent to the first green filter, the third green region is above the third green filter, and the edge of the third green region is offset from an edge of the corresponding third green filter by the third green region offset distance, wherein the offset distance of the first green region and the offset distance of the third green region satisfy the following formula:

number

[0009] In some embodiments, the offset distance of the first green region ranges from 0 to 300 nm, θ is greater than 0 degrees and less than or equal to 35 degrees, and φ is ranges from 0 to 360 degrees.

[0010] In some embodiments, the metasurface layer further comprises a plurality of peripheral nanoposts, the peripheral nanoposts being located at corners of the blue region, the red region, the first green region, and the second green region.

[0011] In some embodiments, the first vertical shift of the first central nanopost is within 1 / 5 of a dimension of the first green filter, and the first horizontal shift of the first central nanopost is within 1 / 5 of a dimension of the first green filter.

[0012] In some embodiments, the first vertical shift and the first horizontal shift have positive shifts. The second vertical shift and the second horizontal shift have positive shifts. The positive shift of the first vertical shift is defined by a shift from the first green region to the red region, and the positive shift of the first horizontal shift is defined by a shift from the first green region to the blue region. The positive shift of the second vertical shift is defined by a shift from the second green region to the blue region, and the positive shift of the second horizontal shift is defined by a shift from the second green region to the red region.

[0013] In some embodiments, the first vertical shift and the first horizontal shift have negative shifts. The second vertical shift and the second horizontal shift have negative shifts. The negative shift of the first vertical shift is defined by a shift from the first green region away from the red region, and the negative shift of the first horizontal shift is defined by a shift from the first green region away from the blue region. The negative shift of the second vertical shift is defined by a shift from the second green region away from the blue region, and the negative shift of the second horizontal shift is defined by a shift from the second green region away from the red region.

[0014] In some embodiments, the metasurface layer further comprises a filler material, the filler material laterally surrounding the first central nanopost and the second central nanopost, and the refractive index of the filler material is in the range of 1.0 to 1.6.

[0015] In some embodiments, the imaging device further comprises a dielectric layer, the dielectric layer being disposed between the color filter layer, the blue filter, the red filter, the first green filter, and the second green filter.

[0016] In some embodiments, the blue region, the red region, the first green region, and the second green region each have a dimension in the range of 400 nm to 700 nm, and the refractive index of the first central nanopost is in the range of 1.8 to 3.5.

[0017] One aspect of the present disclosure provides a method for manufacturing a pixel device. The method includes the following steps: providing a plurality of photodiodes; forming a color filter layer on the plurality of photodiodes, the color filter layer including a blue filter, a red filter, a first green filter, and a second green filter; and forming a metasurface layer on the color filter layer, the metasurface layer including a first pixel unit, the first pixel unit including a blue region on the blue filter, a red region on the red filter, a first green region on the first green filter, and a second green region on the second green filter, the first green region including a first central nanopost, and the second green region including a second central nanopost. Forming the metasurface layer includes the following steps: forming the first central nanopost offset from the center of the first green region by a first vertical shift in the Y-axis direction and a first horizontal shift in the X-axis direction of the first central nanopost, as viewed from above; and forming the second central nanopost offset from the center of the second green region by a second vertical shift in the Y-axis direction and a second horizontal shift in the X-axis direction of the second central nanopost, as viewed from above.

[0018] In some embodiments, the first vertical shift and the first horizontal shift are determined by an angle of incidence and an azimuthal angle of the first green region. The angle of incidence of the first green region is between a first light incident on a top surface of the first green region and a normal to the top surface of the first green region. The azimuthal angle of the first green region is between a horizontal axis of the metasurface layer passing through a center of the metasurface layer and a first connecting line between the center of the first green region and the center of the metasurface layer.

[0019] In some embodiments, forming the metasurface layer further includes forming a plurality of peripheral nanoposts at corners of the blue region, the red region, the first green region, and the second green region.

[0020] In some embodiments, forming the metasurface layer further includes forming a filler material laterally surrounding the peripheral nanoposts, the first central nanopost, and the second central nanopost.

[0021] In some embodiments, the method of manufacturing an imaging device further comprises forming a dielectric layer disposed between a color filter layer, the blue filter, the red filter, the first green filter, and the second green filter.

[0022] In some embodiments, the first vertical shift and the first horizontal shift have positive shifts. The second vertical shift and the second horizontal shift have positive shifts. The positive shift of the first vertical shift is defined by a shift from the first green region to the red region, and the positive shift of the first horizontal shift is defined by a shift from the first green region to the blue region. The positive shift of the second vertical shift is defined by a shift from the second green region to the blue region, and the positive shift of the second horizontal shift is defined by a shift from the second green region to the red region.

[0023] In some embodiments, the first vertical shift and the first horizontal shift have negative shifts. The second vertical shift and the second horizontal shift have negative shifts. The negative shift of the first vertical shift is defined by a shift from the first green region away from the red region, and the negative shift of the first horizontal shift is defined by a shift from the first green region away from the blue region. The negative shift of the second vertical shift is defined by a shift from the second green region away from the blue region, and the negative shift of the second horizontal shift is defined by a shift from the second green region away from the red region. [Brief explanation of the drawings]

[0024] Aspects of the present disclosure may be best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard industry practice, the various features have not been drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or decreased for clarity of illustration. [Figure 1] FIG. 10 is a perspective view of an imaging device in some embodiments of the present disclosure where the incident light is not perpendicularly incident. [Figure 2] FIG. 2 is a side view of a portion of the imaging device of FIG. [Figure 3] FIG. 2 is a top view of the metasurface layer in FIG. 1. [Figure 4A] FIG. 1B is a top view of the layout of metasurface layers for normal incidence of incident light in some embodiments of the present disclosure. [Figure 4B] FIG. 2 shows a top view of the metasurface layer layout of FIG. 1. [Figure 5A] 10 is a coordinate system showing the definitions of various parameters when incident light is perpendicularly incident. [Figure 5B] 10 is a coordinate system showing the definitions of various parameters when incident light is not perpendicularly incident. [Figure 5C] 10 is a coordinate system showing the definitions of various parameters when incident light is not perpendicularly incident. [Figure 5D] 10 is a coordinate system showing the definitions of various parameters when incident light is not perpendicularly incident. [Figure 5E] 1 is an arrangement of metasurface layers according to some embodiments of the present disclosure. [Figure 5F] FIG. 2 is a schematic diagram of a reference point. [Figure 6A] FIG. 10 is a side view of a portion of an imaging device under an incident angle (θi) of a third green region in some embodiments of the present disclosure. [Figure 6B] 1A is a side view of a portion of an imaging device under an incident angle (θ) of a first green region in some embodiments of the present disclosure. [Figure 7]FIG. 1B is a top view of a metasurface layer in some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0025] The following disclosure provides many different embodiments or examples for embodying different features of the given inventive subject matter. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. For example, in the following description, the formation of a first structure that encompasses or builds upon a second structure can include embodiments in which the first and second structures are formed contiguously, and can also include embodiments in which an additional structure can be formed between the first and second structures such that the first and second structures are not directly contiguous.

[0026] Furthermore, the present disclosure may repeat reference numerals and / or characters in various examples. This repetition is for the purposes of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and / or configurations being described.

[0027] Although terms such as "first" and "second" are used herein to describe various elements, it should be understood that these elements are not limited by these terms. These terms are used only to distinguish one element from another. For example, a "first element" could be referred to as a "second element," and similarly, a "second element" could be referred to as a "first element," without departing from the scope of the embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0028] Additionally, spatially relative terms such as "bottom," "lower," "bottom," "upper," "top," and the like, are intended to describe the relationship of one element or feature to another, as shown in the figures, and may be used herein for ease of description. Spatially relative terms are intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may be similarly interpreted.

[0029] In this disclosure, the terms "about," "approximately," and "substantially" generally mean ±20% of the stated value, more generally ±10% of the stated value, even more generally ±5% of the stated value, even more generally ±3% of the stated value, even more generally ±1% of the stated value, and even more generally ±0.5% of the stated value. Stated values ​​in this disclosure are approximate values.

[0030] In light of the continuous miniaturization of pixel size, the light reception of each pixel (which may be defined by different color filters) and the uniformity of light reception between different pixels have become major concerns. If the light reception between different pixels is unbalanced, color variations will occur in the imaging device and the quantum efficiency (QE) between different pixels will be insufficient, thereby degrading the performance of the imaging device. In addition, the angle of incidence of the incident light also affects the quantum efficiency of the imaging device.

[0031] Hereinafter, several embodiments of the present invention will be disclosed in conjunction with the accompanying drawings. For the sake of clarity, many practical details will be described below. However, it should be understood that these practical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these practical details are unnecessary. In addition, in order to simplify the drawings, some conventional structures and elements may be shown in the drawings in a simple schematic manner.

[0032] Because the incident light is a combination of different colors and wavelengths, and photodiodes in the imaging device are used to detect the incident light, the incident light must be separated through a metasurface layer and a color filter layer before being transmitted to the photodiode. The metasurface consists of multiple nanostructures (e.g., nanoposts and pillars) that form specific phase distributions, providing the required phase distribution for different wavelengths. The metasurface directs different incident wavelengths to their respective target locations, also known as color sorting. The target locations here refer to the different color filters in the color filter layer.

[0033] For example, after the phase distribution of the incident wavelength is adjusted, the specific phase distribution can be transmitted to a red color filter that transmits red light, and then the red light can be transmitted to a photodiode under the red color filter, and the electrical signal of the red light can be detected. In this case, the specific phase distribution for the red color filter can be understood as being used for red light.

[0034] In the imaging device disclosed herein, it is believed that different incident angles of incident light in a CMOS array affect the quantum efficiency of different green pixels in a Bayer array. The positions of the nanoposts in the metasurface layer disclosed herein can be adjusted using a disclosed formula calculated based on the incident angle of the incident light and the azimuthal angle of the nanoposts. The disclosed metasurface layer can provide similar quantum efficiencies between different green pixels in a Bayer array, thereby preventing channel separation between different green pixels and improving the performance of the imaging device. Channel separation, as used herein, refers to the imbalance in the quantum efficiencies of the photodiodes of different green pixels.

[0035] FIG. 1 is a perspective view of an imaging device 100 in some embodiments of the present disclosure where the incident light is not normally incident. That is, the incident light L in FIG. 1 is oblique to the top surface of the metasurface 150. FIG. 2 is a side view of a portion of the imaging device 100 in FIG. 1. Specifically, FIG. 2 shows only half of the imaging device 100 in FIG. 1 (such as the blue region BR and the first green region GR1 and their underlying components). FIG. 3 is a top view of the metasurface layer of FIG. 1.

[0036] 1 and 2, the imaging device 100 includes a photovoltaic layer 110. The photovoltaic layer 110 includes a substrate 112, a plurality of deep trench isolations (DTIs) 114, and a plurality of photodiodes .

[0037] 2, the DTIs 114 and photodiodes 116 are embedded in a substrate 112, with each photodiode 116 located between two DTIs 114. In some embodiments, the substrate 112 may be a single structure shared by all of the DTIs 114 and photodiodes 116 of the imaging device 100. The DTIs 114 are configured to avoid optical interference between adjacent photodiodes 116. The photodiodes 116 are configured to sense incident light L and generate intensity signals corresponding to the intensity of the incident light L propagating therethrough. The intensity signals form an image signal.

[0038] In some embodiments, the substrate 112 may be a semiconductor substrate, an organic photovoltaic substrate, a semiconductor-on-insulator (SOI) substrate, or other suitable substrate. In other embodiments, transistors, photodiodes, etc. may be formed in the active regions (defined by the DTIs 114) of the substrate 112. In some embodiments, additional isolation structures, such as shallow trench isolations (STIs) or local oxidation of silicon (LOCOS) structures, may instead be applied. In some embodiments, the DTIs 114 may be formed by a photolithographic process.

[0039] 1 and 2, imaging device 100 includes an anti-reflective layer 120 disposed over substrate 112. Anti-reflective layer 120 is configured to reduce reflection of light transmitted to underlying photodiode 116. In some embodiments, anti-reflective layer 120 is silicon oxynitride (SiO x N, where x and y range from 0 to 1.

[0040] 1 and 2, the imaging device 100 includes a color filter layer 130 disposed on the anti-reflection layer 120. The color filter layer 130 includes multiple color filters, such as a blue filter B, a first green filter G1, a second green filter G2, and a red filter R. As seen from a top view, the color filter layer 130 is arranged in a 2x2 array. In some embodiments, the color filter layer 130 is arranged in a Bayer array. As shown in FIG. 2, the color filter layer 130 further includes multiple grating structures 132 and multiple light-shielding structures 135. The grating structures 132 are disposed adjacent to the color filters. For example, as shown in FIG. 2, the grating structures 132 are disposed adjacent to the blue filter B and the first green filter G1. The grating structures 132 are configured to separate light within specific units and function as light traps. Each light-shielding structure 135 is embedded in one of the grating structures 132. The light blocking structure 135 is configured to prevent the underlying photodiode 116 from receiving additional light from adjacent components of different color.

[0041] In some embodiments, each filter (e.g., blue filter B, first green filter G1, second green filter G2, and red filter R) in color filter layer 130 passes light in a predetermined frequency range. For example, red filter R can transmit light with wavelengths ranging from about 620 nm to about 750 nm (red light) to corresponding photodiodes 116, first green filter G1 and second green filter G2 can transmit light with wavelengths ranging from about 495 nm to about 570 nm (green light) to corresponding photodiodes 116, and blue filter B can transmit light with wavelengths ranging from about 450 nm to about 495 nm to corresponding photodiodes 116. The first green filter G1 can be the same as the second green filter G2.

[0042] In some embodiments, the height of color filter layer 130 ranges from about 0.3 μm to about 2.0 μm, such as 0.5, 0.9, 1.2, 1.5, or 1.8 μm. In some embodiments, the height of grating structure 132 may be greater than or equal to the height of light-shielding structure 135, depending on the design requirements of imaging device 100. In some embodiments, the height of light-shielding structure 135 ranges from about 0.005 μm to about 2.000 μm. In some embodiments, grating structure 132 may be formed of a material including a transparent dielectric material. In some embodiments, light-shielding structure 135 may be formed of a material including an opaque metal, such as tungsten (W), aluminum (Al), an opaque metal nitride, an opaque metal oxide, other suitable materials, or a combination thereof.

[0043] In the present disclosure, one "pixel" is defined by one color filter, and each pixel can correspond to at least one photodiode. Specifically, in the cross-sectional view of FIG. 2, pixel P1 is defined by a blue filter B of the color filter layer 130, and pixel P1 corresponds to two photodiodes 116. The photodiodes 116 below the blue filter B are arranged in a 2x2 array (e.g., a quad photodiode (QPD)). When the photodiodes 116 are arranged in a 2x2 array, the blue filter B corresponds to four photodiodes 116. As shown in FIG. 2, pixel P1 includes a left pixel P1_a and a right pixel P1_b, and each of the left pixel P1_a and the right pixel P1_b corresponds to one photodiode 116.

[0044] Similarly, in the cross-sectional view of FIG. 2, pixel P2 is defined by the first green filter G1 of the color filter layer 130, and pixel P2 corresponds to two photodiodes 116. The photodiodes 116 below the first green filter G1 are arranged in a 2×2 array. As shown in FIG. 2, pixel P2 includes a left pixel P2_a and a right pixel P2_b, each of which corresponds to one photodiode 116. Each DTI 114 can be understood to function as a boundary between the left pixel P1_a, the right pixel P1_b, the left pixel P2_a, or the right pixel P2_b. Each lattice structure 132 can function as a boundary between different pixels (e.g., pixel P1 and pixel P2). The center line (not shown) of the lattice structure 132 can define the boundary between different pixels. That is, the lattice structure 132 in the center of FIG. 2 crosses the boundary between pixel P1 and pixel P2. In some embodiments, the dimensions of each of pixel P1 or pixel P2 range from about 400 nm to about 700 nm, for example, 500 or 600 nm.

[0045] It should be understood that in each pixel (such as pixel P1 or pixel P2), the photodiodes 116 can be arranged in an m×n array, where m and n are positive integers and can be the same or different, but the present disclosure is not limited thereto. For example, the photodiodes 116 under the blue filter B can be arranged in a 1×2 array (e.g., dual photodiode (DPD)), and the photodiodes 116 under the first green filter G1 can be arranged in a 1×2 array. When the photodiodes 116 are arranged in a 1×2 array, the blue filter B corresponds to two photodiodes 116, and the first green filter G1 corresponds to two photodiodes 116.

[0046] 1 and 2, the imaging device 100 includes a dielectric layer 140 (also referred to as a spacer layer) disposed on the color filter layer 130. As shown in FIG. 2, the dielectric layer 140 covers the upper portion 131 of the color filter layer 130 (such as the blue filter B and the first green filter G1) and the grating structure 132. In embodiments of the imaging device 100, the dielectric layer 140 can provide the necessary travel paths for differently diffracted incident light L to reach its respective destination (the different color filters of the color filter layer 130). In some embodiments, the upper portion 131 of each color filter of the color filter layer 130 has a trapezoidal shape in which the top surface is smaller than the bottom surface.

[0047] In some embodiments, the thickness of the dielectric layer 140 is from about 0.1 μm to about 0.5 μm, such as 0.2, 0.3, or 0.4 μm. The dimensions of the dielectric layer 140 can be adjusted depending on the design requirements of the imaging device 100. In some embodiments, the dielectric layer 140 may be formed from materials including silicon oxide, silicon nitride, silicon carbide, silicon carbonitride (SiCN), silicon oxynitride, silicon oxycarbide, tetraethylorthosilicate (TEOS), low-k materials, or other suitable materials.

[0048] 1 and 2, imaging device 100 includes metasurface layer 150 disposed on dielectric layer 140. That is, metasurface layer 150 is disposed on color filter layer 130. As shown in FIGS. 1-3, metasurface layer 150 includes blue region BR, first green region GR1, second green region GR2, and red region RR, which are arranged in a 2×2 array. Specifically, blue region BR is disposed on an underlying blue filter B, first green region GR1 is disposed on an underlying first green filter G1, second green region GR2 is disposed on an underlying second green filter G2, and red region RR is disposed on an underlying red filter R. In some embodiments, each dimension of blue region BR, first green region GR1, second green region GR2, and red region RR ranges from about 400 nm to about 700 nm. In some embodiments, the height of the metasurface layer ranges from about 0.7 μm to about 1.5 μm, e.g., 1.2 μm.

[0049] 1 to 3, the metasurface layer 150 includes a filler 152 and a plurality of nanostructures 154. The filler 152 laterally surrounds the nanostructures 154. The nanostructures 154 include a plurality of peripheral nanoposts 154A and a plurality of central nanoposts 154B. Specifically, the peripheral nanoposts 154A are located at the corners of each of the blue region BR, the first green region GR1, the second green region GR2, and the red region RR. In each of the blue region BR, the first green region GR1, the second green region GR2, and the red region RR, one of the central nanoposts 154B is surrounded by a plurality of peripheral nanoposts 154A.

[0050] 2, peripheral nanopost 154A, located in the center of FIG. 2, crosses the boundary between blue region BR and first green region GR1, while central nanopost 154B does not share an adjacent color region. Each peripheral nanopost 154A is co-located with each lattice structure 132; for example, the centerline of peripheral nanopost 154A is co-located with the centerline of lattice structure 132. To more clearly illustrate the configuration of nanostructures 154, the medium of filler material 152 in FIG. 1 is shown with dashed lines.

[0051] In an embodiment of imaging device 100, nanostructure 154 is a cylinder. In some embodiments, central nanopost 154B and peripheral nanoposts 154A have circular, rectangular, or triangular outlines in a top view. In some other embodiments, multiple intermediate nanoposts (not shown) may be positioned between central nanopost 154B and peripheral nanopost 154A in each of blue region BR, first green region GR1, second green region GR2, and red region RR. In some embodiments, the intermediate nanoposts are arranged in a ring shape, and central nanopost 154B is positioned in a cylindrical shape.

[0052] 2 and 3. The central nanopost 154B of the blue region BR has offset amounts OBxi and OByi relative to the center point BR_C of the blue region BR. The central nanopost 154B of the first green region GR1 has offset amounts OG1xi and OG1yi relative to the center point GR1_C of the first green region GR1. The central nanopost 154B of the second green region GR2 has offset amounts OG2xi and OG2yi relative to the center point GR2_C of the second green region GR2. The central nanopost 154B of the red region RR has offset amounts ORxi and ORyi relative to the center point RR_C of the red region RR. The offset amounts OBxi, OG1xi, OG2xi, and ORxi represent the offset amounts in the X direction when the incident angle of the incident light L is oblique with respect to the top surface of the metasurface layer 150. The offset amounts OByi, OG1yi, OG2yi, and ORyi represent the offset amounts in the Y direction when the incident angle of the incident light L is oblique to the top surface of the metasurface layer 150. In some embodiments, the offset amounts OBxi, OG1xi, OG2xi, ORxi and the offset amounts OByi, OG1yi, OG2yi, and ORyi may be within 1 / 5 of the dimension of the pixel P1 (see FIG. 2). The layout diagram of the nanostructures 154 will be described in detail later in FIG. 4B.

[0053] 4A is a top view of a metasurface layer layout 151a when incident light L is perpendicularly incident, according to some embodiments of the present disclosure. FIG. 5A is a coordinate system illustrating the definition of various parameters when incident light L is perpendicularly incident. In this specification, "perpendicular incidence" refers to the angle of incidence of incident light L being parallel to direction Z.

[0054] In the three-dimensional coordinate system of Fig. 5A, θ is the angle of incidence of incident light L. The angle of incidence θ is equal to 0 degrees when the angle of incidence of incident light L is perpendicular to the XY plane, and the layout diagram 151a shown in Fig. 4A can be understood to be a state in which incident light L is perpendicularly incident. In other words, when the angle of incidence θ is equal to 0, the normal vector of the XY plane is parallel to the angle of incidence of incident light L.

[0055] FIG. 4B is a top view of the layout diagram 151b of the metasurface layer 150 of FIG. 1. FIGS. 5B to 5D are coordinates showing the definitions of various parameters when the incident light L is not perpendicularly incident. It should be understood that the layout diagrams 151a and 151b are different because the difference between the conditions in FIG. 4A and FIG. 4B is the angle of incidence of the incident light L. Specifically, the metasurface layer in FIG. 4A is under the condition that the incident light L is perpendicularly incident, while the metasurface layer in FIG. 4B is under the condition that the incident light L is not perpendicularly incident.

[0056] When the incident light L is not perpendicularly incident (i.e., the incident angle of the incident light L is oblique to the top surface of the metasurface layer 150), the offset amount of the central nanopost 154B in the first green region GR1 and the second green region GR2 has an additional offset amount compared to that in the layout diagram 151a of Figure 4A. Referring to Figures 4A and 4B, the difference between the layout diagrams of Figures 4A and 4B is the position of the central nanopost 154B in the first green region GR1 and the central nanopost 154B in the second green region GR2.

[0057] See FIG. 4A. In the blue region BR, the central nanopost 154B is offset from the center point BR_C by an offset distance and located at an offset position BR_P1, where the offset distance is defined by a horizontal shift BR_dx1 in the X-axis direction and a vertical shift BR_dy1 in the Y-axis direction. In the first green region GR1, the central nanopost 154B is offset from the center point GR1_C by an offset distance and located at an offset position GR1_P1, where the offset distance is defined by a horizontal shift GR1_dx1 in the X-axis direction and a vertical shift GR1_dy1 in the Y-axis direction. In the second green region GR2, the central nanopost 154B is offset from the center point GR2_C by an offset distance and located at an offset position GR2_P1, where the offset distance is defined by a horizontal shift GR2_dx1 in the X-axis direction and a vertical shift GR2_dy1 in the Y-axis direction. In the red region RR, the central nanopost 154B is offset from the center point RR_C by an offset distance and positioned at an offset position RR_P1, where the offset distance is defined by a horizontal shift RR_dx1 in the X-axis direction and a vertical shift RR_dy1 in the Y-axis direction. In this disclosure, a "horizontal shift" can be understood to refer to a shift in a direction parallel to the X-axis, and a "vertical shift" can be understood to refer to a shift in a direction parallel to the Y-axis. In some embodiments, the horizontal and vertical shifts mentioned above can be within ⅕ of the dimension of pixel P1 (see FIG. 2 ).

[0058] 4B, in the first green region GR1, the central nanopost 154B is positioned at an offset position GR1_P2, offset from the offset position GR1_P1 by an additional offset distance, which is defined by a horizontal shift GR1_dx2 in the X-axis direction and a vertical shift GR1_dy2 in the Y-axis direction. In the second green region GR2, the central nanopost 154B is positioned at an offset position GR2_P2, offset from the offset position GR2_P1 by an additional offset distance, which is defined by a horizontal shift GR2_dx2 in the X-axis direction and a vertical shift GR2_dy2 in the Y-axis direction.

[0059] It should be understood that the horizontal shift BR_dx1 and the vertical shift BR_dy1 shown in Figure 4B are equal to the offset amounts OBxi and OByi shown in Figure 3, respectively. The sum of the horizontal shift GR1_dx1 and the horizontal shift GR1_dx2 shown in Figure 4B is equal to the offset amount OG1xi shown in Figure 3, and the sum of the vertical shift GR1_dy1 and the vertical shift GR1_dy2 is equal to the offset amount OG1y shown in Figure 3. The sum of the horizontal shift GR2_dx1 and the horizontal shift GR2_dx2 shown in Figure 4B is equal to the offset amount OG2xi shown in Figure 3, and the sum of the vertical shift GR2_dy1 and the vertical shift GR2_dy2 is equal to the offset amount OG2yi shown in Figure 3. The horizontal shift RR_dx1 and the vertical shift RR_dy1 shown in Figure 4B are equal to the offset amounts ORxi and ORyi shown in Figure 3, respectively.

[0060] In the embodiment of FIG. 4B, the horizontal shift GR1_dx2 in the first green region GR1 is the same as the horizontal shift GR2_dx2 in the second green region GR2, and the vertical shift GR1_dy2 in the first green region GR1 is the same as the vertical shift GR2_dy2 in the second green region GR2.

[0061] See Figures 5B to 5D. θ is the angle of incidence of the incident light L, and φ is the azimuthal angle. When the incident light L is oblique to the top surface of the metasurface layer 150 (see Figure 3), the angle of incidence θ of the incident light L is no longer zero. Therefore, the angle of incidence θ can be defined as the included angle between the incident direction of the incident light L and the normal vector of the XY plane coordinate system. The azimuthal angle corresponds to the included angle on the XY plane coordinate system.

[0062] See the equation below: D GR and D GB are functions of the incident angle θ and the azimuthal angle φ. For the incident angle θ and the incident angle φ, see Figures 5B to 5D.

[0063] As shown in Figures 5B and 5C, positions (r, θ, φ) and (r, θ, φ') have the same incident angle but different azimuth angles, where θ is less than 35 degrees, φ is between 0 and 360 degrees, and φ > φ'. As shown in Figures 5B and 5D, positions (r, θ, φ) and (r, θ', φ) have the same azimuth angle but different incident angles, where θ is less than 35 degrees, φ is between 0 and 360 degrees, and θ' > θ. Any condition in which the incident light L is not perpendicularly incident can be calculated using the following equation: D GR (θ, φ) and D GB (θ, φ) change depending on the incident angle and azimuth angle of the incident light L.

[0064] FIG. 5E illustrates an arrangement of a metasurface layer 150 in some embodiments of the present disclosure. A "pixel unit" herein comprises one blue region BR, one first green region GR1, one second green region GR2, and one red region RR. The metasurface layer 150 comprises multiple pixel units, as shown in FIG. 5E. FIG. 5E illustrates a first pixel unit and a second pixel unit adjacent to the first pixel unit. It is understood that each of the blue region BR, first green region GR1, second green region GR2, and red region RR of the first pixel unit and the second pixel unit includes one central nanopost 154B.

[0065] 4B and 5E, the sum of the horizontal shifts GR1_dx1 and GR1_dx2 in the first green region GR1 is determined by the incident angle θ and azimuth angle φ of the first green region GR1. Similarly, the vertical shifts GR1_dy1 and GR1_dy2 in the first green region GR1 are determined by the incident angle θ and azimuth angle φ of the first green region GR1. The incident angle θ of the first green region GR1 is between the first incident light L (see FIGS. 1 and 5B) on the top surface of the first green region GR1 and the normal to the top surface of the first green region GR1. Referring to FIG. 5E, the azimuth angle φ of the first green region GR1 is between the horizontal axis X of the metasurface layer 150, which passes through the center C of the metasurface layer 150, and the first connecting line CL1 between the center C of the first green region GR1 and the center C of the metasurface layer 150.

[0066] As shown in FIG. 5E, the metasurface layer 150 further includes a second pixel unit, the second pixel unit including a third green region, the third green region including a third central nanopost, the third central nanopost being offset from the center of the third green region by a third vertical shift and a third horizontal shift from the third central nanopost when viewed from above, and the third vertical shift and the third horizontal shift are determined by an incident angle θ of the third green region. i and azimuth angle φ j The incident angle θ of the third green region is determined by i is the angle between the second incident light on the top surface of the third green region and the normal to the top surface of the third green region. j is between the horizontal axis X of the metasurface layer passing through the center C of the metasurface layer 150 and the second connection line CL2 between the center of the third green region and the center C of the metasurface layer 150. The longitudinal shift GR1_dy1 plus the longitudinal shift GR1_dy2 of the central nanopost 154B of the first green region GR1 (see FIG. 4B ) and the third longitudinal shift of the third central nanopost satisfy the following equation:

number

[0067] Figure 5F is a schematic diagram of the reference points. Reference points 1 and 2 are the known D GR (θ i ,φ j) and the reference point 3 above represents the unknown D GR (θ,φ). Reference point 3 can be found from the nearest reference point (reference point 1 or reference point 2, etc.).

[0068] The sum of the horizontal shifts GR1_dx1 and GR1_dx2 of the first central nanopost 154B in the first green region GR1 (see FIG. 4B) and the third horizontal shift of the third central nanopost satisfy the following formula:

number

[0069] In some embodiments, θ is greater than 0 degrees and less than or equal to 35 degrees, and φ is in the range of 0 degrees to 360 degrees.

[0070] After the layout 151b of FIG. 4B is obtained, nanostructures 154 (including peripheral nanoposts 154A and central nanopost 154B) are formed according to the layout 151b, as shown in FIG. 3. In some embodiments, the nanostructures 154 can be formed by any suitable deposition and patterning process, after which the filler material 152 is formed laterally to surround the peripheral nanoposts 154A and central nanopost 154B. In other embodiments, the peripheral nanoposts 154A and central nanopost 154B are formed by etching holes in the filler material 152 after depositing the filler material 152. That is, the nanostructures 154 can be holes filled with ambient air, and the material of the nanostructures 154 is formed in the holes.

[0071] 1-3, in some embodiments, the dimensions (e.g., diameter) of the nanostructures 154 in the top view range from about 120 nm to about 250 nm. The dimensions of the central nanoposts 154B can be the same as or larger than the dimensions of the peripheral nanoposts 154A. Although the nanostructures 154 are depicted as circular in the top view, the present disclosure is not limited in this respect. The nanostructures 154 can have any suitable geometric shape that allows the desired phase distribution of different color light to be formed.

[0072] In some embodiments, the nanostructures 154 can be formed of a material including a transparent conductive material such as indium tin oxide (ITO), tin oxide (SnO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), indium tin zinc oxide (ITZO), antimony tin oxide (ATO), aluminum doped zinc oxide (AZO), titanium dioxide (TiO), or other suitable materials or combinations thereof. In some embodiments, the filler 152 can be formed of a transparent resin such as polyethylene terephthalate (PET) resin, polycarbonate (PC) resin, polyimide (PI) resin, polymethyl methacrylate (PMMA), polystyrene resin, or other suitable materials or combinations thereof.

[0073] In the above formula, D GR and D GB contains positive and negative shifts respectively. D GR A positive shift in is defined as a shift from the green region (such as the first green region GR1 or the second green region GR2) to the red region RR, and D GB A positive shift in is defined as a shift from a green region (such as the first green region GR1 or the second green region GR2) to the blue region BR. Specifically, in the first green region GR1 of FIG. 4B, the vertical shift GR1_dy1 and the vertical shift GR1_dy2 are both D GR The horizontal shift GR1_dx1 and the horizontal shift GR1_dx2 can both be understood as a "positive shift" of D GBIn the second green region GR2 in FIG. 4B, both the horizontal shift GR2_dx1 and the horizontal shift GR2_dx2 are D GR The vertical shift GR2_dy1 and the vertical shift GR2_dy2 can both be understood as a "positive shift" of GB This can be understood as a "positive shift" in

[0074] 3, the horizontal shifts GR1_dx1, GR1_dx2, and vertical shifts GR1_dy1, GR1_dy2 of the first green region GR1 are all positive shifts. Similarly, the horizontal shifts GR2_dx1, GR2_dx2, and vertical shifts GR2_dy1, GR2_dy2 of the second green region GR2 are all positive shifts.

[0075] FIG. 6A illustrates the incident angle θ of the third green region GR3 in some embodiments of the present disclosure. i 6B is a side view of a portion of imaging device 100a under an incident angle θ of a first green region GR1 in some embodiments of the present disclosure.

[0076] As shown in FIG. 6B, the edge of the first green region GR1 is offset from the edge of the corresponding first green filter G1 by the offset distance of the first green region GR1. The color filter layer 130 includes a third green filter G3 (see FIG. 6A) adjacent to the first green filter G1 (see FIG. 6B). As shown in FIG. 6A, the third green region GR3 is located above the third green filter G3, and the edge of the third green region GR3 is offset from the edge of the corresponding third green filter G3 by the offset distance of the third green region GR3. The offset distance of the first green region GR1 and the offset distance of the third green region GR3 satisfy the following formula:

number

[0077] In some embodiments, the offset distance S(θ) ranges from about −P½ to about P½. In some embodiments, when θ is 0 degrees, the offset distance S(θ) is 0 nm. In some embodiments, when θ is 7.5 degrees, the offset distance S(θ) is 72 nm. In some embodiments, when θ is 15 degrees, the offset distance S(θ) is 157 nm. In some embodiments, when θ is 22.5 degrees, the offset distance S(θ) is 209 nm. In some embodiments, when θ is 30 degrees, the offset distance S(θ) is 291 nm.

[0078] The manufacturing method of the imaging device 100 includes the following steps: a photoelectric conversion layer 110 is formed; an anti-reflection layer 120 is formed on the photoelectric conversion layer 110; a color filter layer 130 is formed on the anti-reflection layer 120; a dielectric layer 140 is formed on the color filter layer 130; a metasurface layer 150 (including peripheral nanoposts 154A and central nanoposts 154B) is formed on the dielectric layer 140, where the metasurface layer 150 is formed according to the layout diagram 151b.

[0079] 7 is a top view of a metasurface layer 750 according to some embodiments of the present disclosure. The difference between the metasurface layer 750 of FIG. 7 and the metasurface layer 150 of FIG. 3 is the position of the central nanopost 154B in each of the blue region BR, the first green region GR1, the second green region GR2, and the red region RR. The central nanopost 154B in FIG. 7 has a negative shift. In the present disclosure, D GRの A negative shift is defined as a shift from the green region (such as the first green region GR1 or the second green region GR2) away from the red region RR, and D GBA negative shift is defined as a shift away from the blue region BR as viewed from the green region (such as the first green region GR1 or the second green region GR2). Specifically, in the first green region GR1 in FIG. 7, the vertical shift GR1_dy1 and the vertical shift GR1_dy2 are both D GR The horizontal shift GR1_dx1 and the horizontal shift GR1_dx2 can both be understood as "negative shifts" of the GB In the second green region GR2 in FIG. 7, the horizontal shift GR2_dx1 and the horizontal shift GR2_dx2 are both D GR Both the vertical shift GR2_dy1 and the vertical shift GR2_dy2 can be understood as a "negative shift" of GB This can be understood as a "negative shift" of

[0080] 7, the horizontal shifts GR1_dx1, GR1_dx2, and vertical shifts GR1_dy1, GR1_dy2 of the first green region GR1 are all negative shifts, and similarly, the horizontal shifts GR2_dx1, GR2_dx2, and vertical shifts GR2_dy1, GR2_dy2 of the second green region GR2 are all negative shifts.

[0081] See imaging device 100 in FIG. 2. In some embodiments, the refractive index of nanostructure 154 (including peripheral nanoposts 154A and central nanopost 154B) is greater than the refractive index of filler material 152. In some embodiments, the refractive index of peripheral nanoposts 154A is equal to the refractive index of central nanopost 154B. In some embodiments, the refractive index of peripheral nanoposts 154A ranges from about 1.8 to about 3.5, e.g., 2.0, 2.5, or 3.0. In some embodiments, the refractive index of central nanopost 154B ranges from about 1.8 to about 3.5, e.g., 2.0, 2.5, or 3.0. In some embodiments, the refractive index of filler material 152 ranges from about 1.0 to about 1.6, e.g., 1.2 or 1.4. In some embodiments, filler material 152 can be air. It is worth noting that when the nanostructures 154 are surrounded by ambient air (the refractive index of the filler 152 is 1), the difference between the refractive indices may be greatest, and a significantly broader phase distribution may be achieved, thereby making it easier to separate the incident light L based on different wavelengths. In some embodiments, the radii of the central nanoposts 154B in each of the blue region BR, the first green region GR1, the second green region GR2, and the red region RR are different from each other. The dimensions of each central nanopost 154B can be adjusted according to the design requirements of the imaging device 100.

[0082] Referring again to imaging device 100 in FIG. 2 , in some embodiments, the refractive index of dielectric layer 140 is less than the refractive index of nanostructures 154. In some embodiments, the refractive index of dielectric layer 140 ranges from about 1.0 to about 1.6, such as 1.2 or 1.4. In some embodiments, the refractive index of each filter (e.g., blue filter B, first green filter G1, second green filter G2, and red filter R) in color filter layer 130 is greater than the refractive index of grating structure 132. In some embodiments, the refractive index of each filter in color filter layer 130 ranges from about 1.4 to about 2.3, such as 1.6, 1.8, 2.0, or 2.2. In some embodiments, the refractive index of grating structure 132 ranges from about 1.0 to about 1.3, such as 1.1 or 1.2.

[0083] The present disclosure provides a method for forming a metasurface layer in which the central nanoposts in the green region have an additional offset distance compared to the central nanoposts in the blue and red regions, taking into account the condition that the incident light L is not perpendicularly incident. The additional offset distance can be calculated using the above formula. The metasurface layer of the present disclosure can tolerate incident light at a wide range of incident angles and provide balanced values ​​of quantum efficiency for different green pixels in a Bayer array. The disclosed metasurface layer can provide similar values ​​of quantum efficiency between different green pixels, thereby avoiding channel separation between different green pixels and improving the performance of the imaging device.

[0084] Although the present disclosure has been disclosed as above in the above specification, it is not used to limit the present disclosure. Those skilled in the art can make various changes, substitutions and alterations in this specification without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure is intended to be covered by the claims attached hereto and equivalent structures.

Claims

1. a plurality of photodiodes; a color filter layer overlying the plurality of photodiodes, the color filter layer including a blue filter, a red filter, a first green filter, and a second green filter; a metasurface layer on the color filter layer, the metasurface layer including a first pixel unit, the first pixel unit including a blue region on the blue filter, a red region on the red filter, a first green region on the first green filter, and a second green region on the second green filter; An imaging device comprising: the first green region includes a first central nanopost, the first central nanopost being offset from a center of the first green region by a first vertical shift in a Y-axis direction and a first horizontal shift in an X-axis direction of the first central nanopost when viewed from above; The second green region includes a second central nanopost, and the second central nanopost is offset from the center of the second green region by a second vertical shift in the Y-axis direction and a second horizontal shift in the X-axis direction of the second central nanopost when viewed from above.

2. the first vertical shift and the first horizontal shift are determined by an incident angle and an azimuth angle of the first green region; the angle of incidence of the first green region is between a first incident light on a top surface of the first green region and a normal to the top surface of the first green region; 2. The pixel device of claim 1, wherein the azimuthal angle of the first green region is between a horizontal axis of the metasurface layer passing through a center of the metasurface layer and a first connecting line between the center of the first green region and the center of the metasurface layer.

3. the metasurface layer further comprises a second pixel unit, the second pixel unit comprising a third green region; the third green region includes a third central nanopost, the third central nanopost being offset from the center of the third green region by a third vertical shift in a Y-axis direction and a third horizontal shift in an X-axis direction of the third central nanopost when viewed from above; the third vertical shift and the third horizontal shift are determined according to an incident angle and an azimuth angle of the third green region, the angle of incidence of the third green region is between the second incident light on the top surface of the third green region and a normal to the top surface of the third green region; the azimuthal angle of the third green region is between the horizontal axis of the metasurface layer, which passes through the center of the metasurface layer, and a second connecting line between the center of the third green region and the center of the metasurface layer; The first longitudinal shift of the first central nanopost and the third longitudinal shift of the third central nanopost satisfy the following formula: [Equation 1] where θ is the angle of incidence of the first green region, and θ is not 0 degrees, φ is the azimuthal angle of the first green region, D ＧＲ (θ, φ) is the first longitudinal shift of the first central nanopost; θ ｉ is the angle of incidence of the third green region, and θ ｉ is not 0 degrees, φ ｊ is the azimuth angle of the third green region, D ＧＲ (θ ｉ , φ ｊ ) is the third longitudinal shift of the third central nanopost; Δθ is a first difference between the angle of incidence of the first green region and the angle of incidence of the third green region; 3. The pixel device of claim 2, wherein Δφ is a second difference between the azimuthal angle of the first green region and the azimuthal angle of the third green region.

4. The first horizontal shift of the first central nanopost and the third horizontal shift of the third central nanopost satisfy the following formula: [Equation 2] Here, D ＧＢ (θ, φ) is the first horizontal shift of the first central nanopost; D ＧＢ (θ ｉ , φ ｊ 4. The pixel device of claim 3, wherein: ##EQU1## is the third horizontal shift of the third central nanopost.

5. an edge of the first green region is offset from an edge of the corresponding first green filter by an offset distance of the first green region; the color filter layer includes a third green filter adjacent to the first green filter, the third green region being above the third green filter, and the edge of the third green region is offset from an edge of the corresponding third green filter by the offset distance of the third green region; The offset distance of the first green region and the offset distance of the third green region satisfy the following formula: [Equation 3] where S(θ) is the offset distance of the first green region; S (θ ｉ ) is the offset distance of the third green region, the offset distance of the first green region is in the range of 0 to 300 nm; θ is greater than 0 degrees and less than or equal to 35 degrees, 5. The pixel device of claim 4, wherein φ ranges from 0 to 360 degrees.

6. the metasurface layer further comprises a plurality of peripheral nanoposts and a filler material, the peripheral nanoposts being located at corners of the blue region, the red region, the first green region, and the second green region, the filler material laterally surrounding the first central nanopost and the second central nanopost, and a refractive index of the filler material being in the range of 1.0 to 1.6; the imaging device further comprises a dielectric layer, the dielectric layer being disposed between the color filter layer, the blue filter, the red filter, the first green filter, and the second green filter; 2. The pixel device of claim 1, wherein the blue region, the red region, the first green region, and the second green region each have a dimension in the range of 400 nm to 700 nm, and the refractive index of the first central nanopost is in the range of 1.8 to 3.

5.

7. 2. The pixel device of claim 1, wherein the first vertical shift of the first central nanopost is within 1 / 5 of a dimension of the first green filter, and the first horizontal shift of the first central nanopost is within 1 / 5 of a dimension of the first green filter.

8. the first vertical shift and the first horizontal shift have positive shifts; the second vertical shift and the second horizontal shift have positive shifts; the positive shift of the first vertical shift is defined by a shift from the first green region to the red region, and the positive shift of the first horizontal shift is defined by a shift from the first green region to the blue region; 2. The pixel device of claim 1, wherein the positive shift of the second vertical shift is defined by a shift from the second green region to the blue region, and the positive shift of the second horizontal shift is defined by a shift from the second green region to the red region.

9. the first vertical shift and the first horizontal shift have negative shifts; the second vertical shift and the second horizontal shift have negative shifts; the negative shift of the first vertical shift is defined as a shift from the first green region away from the red region, and the negative shift of the first horizontal shift is defined as a shift from the first green region away from the blue region; 2. The pixel device of claim 1, wherein the negative shift of the second vertical shift is defined by a shift from the second green region away from the blue region, and the negative shift of the second horizontal shift is defined by a shift from the second green region away from the red region.

10. 1. A method for manufacturing a pixel device, comprising: A plurality of photodiodes are provided, forming a color filter layer on the plurality of photodiodes, the color filter layer including a blue filter, a red filter, a first green filter, and a second green filter; A metasurface layer is formed on the color filter layer, the metasurface layer having a first pixel unit, the first pixel unit having a blue region on the blue filter, a red region on the red filter, a first green region on the first green filter, and a second green region on the second green filter, the first green region having a first central nanopost and the second green region having a second central nanopost, and the formation of the metasurface layer is forming the first central nanopost offset from the center of the first green region in a top view by a first vertical shift in a Y-axis direction of the first central nanopost and a first horizontal shift in an X-axis direction; forming the second central nanopost offset from the center of the second green region by a second vertical shift in the Y-axis direction and a second horizontal shift in the X-axis direction of the second central nanopost, when viewed from above.

Images