Wire grid polarizer and preparation method therefor, display device and electronic apparatus
By designing a cavity structure and etching method in the online grid polarizer, the problem of insufficient groove etching accuracy was solved, the groove depth consistency and extinction ratio were improved, and the optical performance and signal transmission quality were enhanced.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- HUAWEI TECH CO LTD
- Filing Date
- 2025-08-04
- Publication Date
- 2026-07-30
AI Technical Summary
Existing wire grid polarizers have difficulty controlling the precision during the etching of grooves, resulting in poor groove size consistency and affecting optical performance.
Design a wire grid polarizer structure in which a cavity is formed between adjacent wire grids. The cavity is composed of a first part and a second part. The groove opening faces the cavity. During etching, the reactive gas flows back in the cavity to ensure full contact with the substrate, reduce the use of bias voltage, and improve etching uniformity and depth consistency.
This improved the depth uniformity and extinction ratio of the groove, enhanced the transmittance and optical performance of the wire grid polarizer for horizontally polarized light, reduced power consumption, and ensured signal transmission quality.
Smart Images
Figure CN2025112547_30072026_PF_FP_ABST
Abstract
Description
Wire grid polarizer and its fabrication method, display device, electronic device
[0001] This application claims priority to Chinese Patent Application No. 202510125746.3, filed on January 26, 2025, entitled "Wire grating polarizer and preparation method, display device, electronic device", the entire contents of which are incorporated herein by reference. Technical Field
[0002] This application relates to the field of display technology, and in particular to a wire grid polarizer and its fabrication method, a display device, and an electronic device. Background Technology
[0003] A polarizing beam splitter (PBS), or simply a polarizer, is an optical device that separates incident light into those with different polarization states (i.e., different directions). A wire grating polarizer is one type of polarizer structure, consisting of multiple parallel wire gratings (also called gratings). Horizontally (P) polarized light in the incident light is parallel to the direction of the gratings and can pass through the wire grating polarizer, while vertically (S) polarized light is perpendicular to the direction of the gratings and is reflected by the wire grating polarizer.
[0004] The principle of the aforementioned wire grating polarizer is based on the resonance effect of light, which refers to the phenomenon where incident light interacts with the wire grating and resonates. However, the resonance intensity between incident light with shorter wavelengths (e.g., less than 0.5 μm) and the wire grating is greater, resulting in better selective transmission. Conversely, the resonance effect between incident light with longer wavelengths (e.g., greater than 0.5 μm) and the wire grating is weaker, leading to greater loss and lower transmittance of horizontally polarized light passing through the wire grating.
[0005] Currently, grooves are created on the substrate surface between two adjacent wire grids to enhance the resonance effect between longer wavelength incident light and the wire grids, thereby improving the transmittance of horizontally polarized light. However, due to the small size of the grooves, it is difficult to control the precision during etching, resulting in poor dimensional consistency of the grooves, which affects the optical performance of the wire grid polarizer. Summary of the Invention
[0006] This application provides a wire grid polarizer and its fabrication method, a display device, and an electronic device to improve the etching accuracy of the grooves in the wire grid polarizer, thereby improving the dimensional consistency of the grooves.
[0007] In a first aspect, this application provides a wire grid polarizer, including a substrate, a plurality of wire grids and a plurality of grooves. The substrate has a first surface facing a first direction. The plurality of wire grids are located on the first surface and arranged at intervals along a second direction. A cavity is formed between adjacent wire grids. The cavity includes a first part and a second part connected sequentially along the first direction. The first part is located at the end of the cavity. The dimension of the first part along the second direction is larger than the dimension of the second part along the second direction. The first direction and the second direction are perpendicular. The plurality of grooves are formed on the first surface. A groove is formed between adjacent wire grids. The opening of the groove faces the cavity.
[0008] Thus, during the etching process to form the grooves, the reactive gas, upon contacting the first surface of the substrate, experiences backflow within the first portion of the cavity and does not immediately overflow from the second portion. This allows the reactive gas to fill the first portion of the cavity, ensuring sufficient contact between the first surface of the substrate and the reactive gas, thereby improving etching uniformity. Furthermore, because the reactive gas can maintain sufficient contact with the first surface of the substrate, it is not necessary to apply a bias voltage to the reactive gas during etching, thus slowing down the etching rate and improving the controllability of the groove etching, ultimately enhancing the uniformity of the groove depth.
[0009] Understandably, the aforementioned structure of the wire-grid polarizer can also improve its extinction ratio. The extinction ratio refers to the ratio of the transmittance of horizontally polarized light to the transmittance of vertically polarized light in a wire-grid polarizer. A higher extinction ratio indicates higher transmittance of horizontally polarized light and lower transmittance of vertically polarized light, resulting in a stronger ability of the wire-grid polarizer to separate different polarized light states and better optical performance. Therefore, because the aforementioned wire-grid polarizer structure can improve the uniformity of groove depth, resulting in smaller groove depth deviations and closer approximation to the design dimensions, it improves the transmittance of horizontally polarized light and the overall extinction ratio of the wire-grid polarizer.
[0010] In some embodiments of the first aspect described above, the depth difference between any two grooves is less than or equal to 15% of the groove depth. For example, the depth difference between any two grooves can be 1%, 5%, 8%, 10%, or 15% of the groove depth, etc., to improve the consistency of groove depth.
[0011] In some embodiments of the first aspect described above, the wire grid body includes a first wire grid portion and a second wire grid portion connected to each other, the first portion being located between adjacent first wire grid portions, the second portion being located between adjacent second wire grid portions, and the size of the second wire grid portion in the first direction being less than or equal to the size of the first wire grid portion in the first direction.
[0012] This allows the narrower first wire grid portion to occupy a larger proportion of the entire wire grid, thereby keeping the resistance of the wire grid at a low value and reducing the power consumption of the wire grid polarizer. Furthermore, during current transmission, the narrower first wire grid portion leads to reduced signal attenuation or distortion, thus improving the uniformity of the groove depth while ensuring the transmission quality of the optical signal (i.e., incident light) and other related optical properties of the wire grid.
[0013] In some embodiments of the first aspect described above, the surface of the second wire grid portion facing the second portion is an arc surface.
[0014] Thus, due to the high surface smoothness of the curved surface, the reactant gas can enter the first part of the cavity more smoothly, thereby facilitating the formation of backflow in the first part and improving the etching uniformity and depth consistency of the groove. It should be noted that in some other embodiments, the side surface of the second grid portion can also be other shapes, such as a plane, etc. This application does not impose any limitations on the surface shape of the second grid portion.
[0015] In some embodiments of the first aspect described above, the size of the first wire gate portion along the second direction is 50nm to 80nm, and the size of the second wire gate portion along the second direction is 70nm to 90nm.
[0016] For example, the width of the first line gate portion can be 50nm, 60nm, 70nm, or 80nm, etc., and the width of the second line gate portion can be 70nm, 80nm, or 90nm, etc. In other embodiments of this application, the width of the second line gate portion can also be 110% to 140% of the width of the first line gate portion. It should be noted that this application does not impose any limitations on the specific dimensions of the first and second line gate portions, and those skilled in the art can select other dimensions according to actual needs.
[0017] In some embodiments of the first aspect described above, the cavity further includes a third portion, the second portion and the third portion being connected sequentially along a first direction, and the dimension of the third portion along the second direction being greater than the dimension of the second portion along the second direction.
[0018] In this way, when the reactant gas is introduced into the cavity, it will first enter the wider third part, which allows the reactant gas to enter the cavity more smoothly and improves the efficiency of reactant gas introduction.
[0019] In some embodiments of the first aspect described above, the wire grid body further includes a third wire grid portion, which is connected to the second wire grid portion. The third portion is located between adjacent third wire grid portions, and the size of the third wire grid portion along the second direction is 50 nm to 80 nm.
[0020] For example, the width of the third gate portion can be 50nm, 60nm, 70nm, or 80nm, etc. It should be noted that this application does not impose any limitations on the specific size of the third gate portion, and those skilled in the art can choose other sizes according to actual needs.
[0021] In some embodiments of the first aspect described above, the dimension of the second wire grid portion in the first direction is less than or equal to the sum of the dimensions of the first wire grid portion and the third wire grid portion in the first direction.
[0022] Therefore, as mentioned above, the narrower first wire grating portion occupies a larger proportion of the entire wire grating, thereby ensuring the signal transmission quality and other related optical properties of the wire grating.
[0023] In some embodiments of the first aspect described above, the depth of the groove is 5 nm to 50 nm. For example, the depth of the groove 105 can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, or 50 nm, etc.
[0024] In some embodiments of the first aspect described above, the cross-sectional shape of the groove is one of a rectangle, a square, a semicircle, or a triangle, and the cross-section is parallel to the first direction and parallel to the second direction.
[0025] It should be noted that this application does not impose any restrictions on the cross-sectional shape of the groove, and those skilled in the art can choose other shapes according to actual needs.
[0026] In some embodiments of the first aspect described above, the wire grid polarizer further includes a transparent layer located on the surface of the wire grid body facing the first direction.
[0027] In this way, the transparent layer can provide a physical barrier for the wire grating, protecting the upper surface of the wire grating from the influence of external environmental factors (such as pollution, mechanical damage, etc.). Furthermore, due to the high light transmittance of the transparent layer, it will not interfere with the incident light, thus protecting the wire grating without affecting the optical performance of the wire grating polarizer.
[0028] In some embodiments of the first aspect described above, the surface of the transparent layer facing the first direction is curved.
[0029] Thus, the curved surface can adjust the angle of the incident light, concentrating it onto the lower wire grid, further improving the transmittance of the wire grid polarizer. Furthermore, the curved surface of the transparent layer reduces the deflection or distortion of the incident light when it strikes the upper surface of the wire grid, thereby better matching the propagation path of the incident light and reducing changes in the refraction angle, thus reducing distortion. It should be noted that in some other embodiments, the surface of the transparent layer facing the first direction can also be other shapes, such as a plane. This application does not impose any limitations on the shape of the surface of the transparent layer facing the first direction.
[0030] In a second aspect, this application provides a display device including a light-emitting module and a wire grid polarizer described in the first aspect above, wherein the light-emitting module is used to provide incident light to the wire grid polarizer.
[0031] Thirdly, this application provides an electronic device including a housing and a display device described in the second aspect above, the display device being located within the housing.
[0032] Fourthly, this application provides a method for fabricating a wire grid polarizer, comprising: providing a substrate having a first surface facing a first direction; forming a plurality of wire grids spaced apart along a second direction on the first surface, wherein a cavity is formed between adjacent wire grids, the cavity comprising a first portion and a second portion connected sequentially along the first direction, the first portion being located at the end of the cavity, the dimension of the first portion along the second direction being larger than the dimension of the second portion along the second direction, and the first direction and the second direction being perpendicular; etching the first surface to form a plurality of grooves, and forming a groove between adjacent wire grids, the opening of the groove facing the cavity.
[0033] In some embodiments of the fourth aspect described above, etching the first surface to form a plurality of grooves includes: introducing a reactive gas into a cavity and etching the first surface between adjacent grid cells based on the reactive gas to form a plurality of grooves.
[0034] In some embodiments of the fourth aspect described above, introducing a reactive gas into the cavity includes: introducing a reactive gas into the cavity when the bias voltage is less than or equal to 0.1V.
[0035] The beneficial effects of the second to fourth aspects described above can be referred to the relevant descriptions in the various embodiments of the first aspect described above, and will not be repeated here. Attached Figure Description
[0036] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.
[0037] Figure 1 shows a cross-sectional schematic diagram of a first type of wire grid polarizer according to some embodiments of this application;
[0038] Figure 2 shows a cross-sectional schematic diagram of a second type of wire grid polarizer according to some embodiments of this application;
[0039] Figure 3 shows a graph of the relationship between the groove depth and transmittance of a wire grid polarizer according to some embodiments of this application;
[0040] Figure 4 shows a cross-sectional schematic diagram of a third type of wire grid polarizer according to some embodiments of this application;
[0041] Figure 5 shows a cross-sectional schematic diagram of a fourth type of wire grid polarizer according to some embodiments of this application;
[0042] Figure 6 shows a cross-sectional schematic diagram of a fifth type of wire grid polarizer according to some embodiments of this application;
[0043] Figure 7 shows a cross-sectional schematic diagram of a sixth type of wire grid polarizer according to some embodiments of this application;
[0044] Figure 8 shows a cross-sectional schematic diagram of a seventh type of wire grid polarizer according to some embodiments of this application;
[0045] Figure 9 shows a cross-sectional schematic diagram of an eighth type of wire grid polarizer according to some embodiments of this application;
[0046] Figure 10 shows a cross-sectional schematic diagram of a ninth type of wire grid polarizer according to some embodiments of this application;
[0047] Figure 11 shows a cross-sectional schematic diagram of a tenth type of wire grid polarizer according to some embodiments of this application;
[0048] Figure 12 shows a schematic diagram of the cross-sectional structure and corresponding performance parameters of three different wire grid polarizers according to some embodiments of this application;
[0049] Figure 13 shows a schematic flowchart of a method for fabricating a wire grid polarizer according to some embodiments of this application. Detailed Implementation
[0050] The illustrative embodiments of this application include, but are not limited to, wire grid polarizers and their fabrication methods, display devices, and electronic devices.
[0051] It is understood that the wire grid polarizer mentioned in the embodiments of this application can be applied to any electronic device including display functions. These electronic devices include, but are not limited to, mobile phones, smart TVs, wearable devices, tablets, desktop computers, laptops, virtual reality (VR) devices, augmented reality (AR) devices, electronic devices in industrial control, electronic devices in self-driving vehicles, electronic devices in remote medical surgery, electronic devices in smart grids, electronic devices in transportation safety, electronic devices in smart cities, electronic devices in smart homes, and so on. The embodiments of this application do not limit the specific form of the electronic device.
[0052] Furthermore, the aforementioned electronic device may include a display device for implementing the display function of the electronic device. The display device includes the line grid polarizer mentioned in the embodiments of this application. The display device may be a head-up display (HUD) device or other device that needs to project images (also referred to as an optomechanical system). For example, in the embodiments of this application, the display device may be a head-up display device applied in a vehicle. The head-up display device can project instrument information (such as vehicle speed, temperature, fuel level, etc.) and navigation information through the vehicle's windshield into the driver's field of vision, allowing the driver to obtain the necessary information during driving without looking down at the instrument panel or control screen. It should be noted that the above application scenarios are not intended to limit this application; the line grid polarizer and display device provided in this application can also be applied in other scenarios.
[0053] The basic structure and principle of a currently used wire grating polarizer are explained below with reference to Figure 1.
[0054] Figure 1 shows a schematic cross-sectional view of a wire grid polarizer 10, specifically a cross-section parallel to the XZ plane.
[0055] Referring to Figure 1, the wire grid polarizer 10 includes a substrate 101 and a plurality of parallel-spaced wire grids 102 disposed on the substrate 101, wherein the substrate 101 is a light-transmitting material, such as glass, and the wire grids 102 are made of a metallic material.
[0056] Before introducing the principle of the wire grid polarizer 10, the X-axis, Y-axis, and Z-axis directions of the wire grid polarizer 10 are defined with reference to Figure 1. As shown in Figure 1, the X-axis direction is the arrangement direction of the multiple wire grid bodies 102, the Y-axis direction is the extension direction of the wire grid bodies 102, and the Z-axis direction is the thickness direction of the substrate 101, that is, the height direction of the wire grid bodies 102 and the thickness direction of the wire grid polarizer 10. The positive Z-axis direction can be the direction from the substrate 101 to the wire grid bodies 102. In some embodiments of this application, the X-axis, Y-axis, and Z-axis directions intersect each other. In some implementations, the X-axis, Y-axis, and Z-axis directions can be perpendicular to each other.
[0057] Additionally, it should be noted that the directional terms such as "upper," "lower," "left," "right," "top," "bottom," and "above" used herein refer to exemplary orientations shown in the accompanying drawings corresponding to the embodiments, and do not indicate or imply that the components referred to must have a specific orientation. These terms can vary according to actual use and should not be construed as limiting this application. Furthermore, it is understood that when the viewing angle of the accompanying drawings changes (e.g., the drawings are rotated at any angle for reference), the directional terms also change accordingly.
[0058] It is understood that the perpendicularity in this application is not absolute perpendicularity. Approximate perpendicularity due to processing and assembly errors (e.g., an angle of 89° between two structural features) is also within the scope of mutual perpendicularity in this application. Similarly, the parallelism in this application is not absolute parallelism. Approximate parallelism due to processing and assembly errors (e.g., an angle of 1° between two structural features) is also within the scope of mutual parallelism in this application. The limitations of mutual parallelism and mutual perpendicularity will not be repeated below.
[0059] Referring again to Figure 1, the principle of the wire grid polarizer 10 is to achieve selective transmission of incident light 11 using the wire grid 102. Specifically, the incident light 11 includes vertically polarized light 111 and horizontally polarized light 112. The horizontally polarized light 112 is parallel to the extension direction of the wire grid 102 (i.e., the Y-axis direction) and can pass through the wire grid polarizer 10. The vertically polarized light 111 is perpendicular to the extension direction of the wire grid 102 (i.e., the Y-axis direction) and will be reflected by the wire grid polarizer 10.
[0060] The selective transmission of the linear grating polarizer 10 is achieved by utilizing the resonance effect of light. When incident light with a shorter wavelength (e.g., less than 0.5 μm) enters the grating, the resonance effect is stronger, resulting in higher transmittance of the horizontally polarized light 112. When incident light with a longer wavelength (e.g., greater than 0.5 μm) enters the grating, the resonance effect is weaker, and the grating 102 causes loss to the incident light 11, resulting in lower transmittance of the horizontally polarized light 112.
[0061] It should be noted that, in the embodiments of this application, the incident light can also be incident on the line grid polarizer from any other direction, and this application does not impose any restrictions on the incident direction of the incident light.
[0062] To address the aforementioned issues, the basic structure and principle of another currently used linear grid polarizer will be explained below with reference to Figures 2 and 3.
[0063] Figure 2 shows a schematic cross-sectional view of a wire grating polarizer 20, specifically a cross-section parallel to the XZ plane. Compared to the wire grating polarizer 10 in Figure 1, the wire grating polarizer 20 has grooves 103 formed on the substrate 101 between adjacent wire gratings 102. The grooves 103 can change the resonance intensity between the wire gratings 102 and the incident light, making the resonance characteristics of longer wavelength incident light closer to those of shorter wavelength incident light. In other words, it can enhance the resonance intensity between incident light of different wavelengths and the wire gratings 102, thereby improving the transmittance of horizontally polarized light.
[0064] Figure 3 shows a graph illustrating the relationship between the groove depth of a wire grating polarizer 20 and the transmittance (i.e., transmissivity) of horizontally polarized light. Referring to Figure 3, different curves correspond to wire grating polarizers with different focal lengths ff, where the focal length ff is the reciprocal of the period P1 of the wire grating polarizer 20. Combining with Figure 2, the period P1 of the wire grating polarizer 20 refers to the sum of the distance between adjacent wire grating bodies 102 and the width of one wire grating body 102 (i.e., the dimension along the X-axis). It can be seen that, considering the curve trends of wire grating polarizers with different focal lengths ff, the wire grating polarizer 20 exhibits the highest transmittance for horizontally polarized light when the groove depth (i.e., the dimension along the Z-axis) is approximately 20 nm. Therefore, the groove depth 103 is currently generally set to 20 nm to improve the optical performance of the wire grating polarizer 20.
[0065] However, since the size of the groove 103 is typically in the nanometer range, the process window during the etching process is very small, making it difficult to control dimensional accuracy during etching. Specifically, the groove 103 is usually etched using a dry etching method. To ensure sufficient contact between the reactive gas and the surface of the substrate 101 for uniform etching, a certain pressure (i.e., a bias voltage) needs to be applied to the reactive gas. Understandably, with a small process window, the etching rate is very sensitive to changes in the bias voltage. A slightly lower bias voltage will result in an insufficient etching rate for the groove 103, while a slightly higher bias voltage will result in an excessive etching rate, leading to over-etching. Consequently, the depth uniformity of the groove 103 is poor, making it difficult to approach the preset design size (e.g., 20 nm), thus affecting the optical performance of the wire grid polarizer 20.
[0066] To address the aforementioned issues, this application provides a wire-grid polarizer. The polarizer includes a substrate and a plurality of wire grids located on a first surface of the substrate. The wire grids are uniformly spaced along the positive X-axis, and cavities are formed between adjacent wire grids. Each cavity includes a first portion and a second portion connected sequentially along the positive Z-axis. The first portion is located at the end of the cavity, and its dimension along the positive X-axis is larger than that of the second portion. Grooves are also formed on the first surface between adjacent wire grids, with the openings of the grooves facing the cavities. Thus, during the etching process to form the grooves, the reactive gas, upon contacting the first surface of the substrate, will flow back into the first portion of the cavity and will not immediately overflow from the second portion. This allows the reactive gas to fill the first portion of the cavity, achieving sufficient contact between the first surface of the substrate and the reactive gas, thus improving etching uniformity. Furthermore, because the reactive gas can fully contact the first surface of the substrate, it is not necessary to apply a bias voltage to the reactive gas during etching, thereby slowing down the etching rate and improving the controllability of groove etching, thus enhancing the uniformity of groove depth.
[0067] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, this application will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0068] An embodiment of the wire grid polarizer of this application will be described in detail below with reference to Figure 4.
[0069] Figure 4 shows a cross-sectional schematic diagram of a wire grid polarizer 30, specifically a cross-sectional schematic diagram of the part of the wire grid polarizer 30 parallel to the XZ plane.
[0070] Referring to Figure 4, the wire grid polarizer 30 includes a substrate 101, a plurality of wire grids 104, and a plurality of grooves 105. The substrate 101 has a surface S1 (as a first surface) facing the positive Z-axis direction (as an example of a first direction). The plurality of wire grids 104 are located on surface S1 and spaced apart along the positive X-axis direction (as an example of a second direction). A cavity 106 is formed between adjacent wire grids 104. The cavity includes a first portion 1061 and a second portion 1062 connected sequentially along the positive Z-axis direction. The first portion 1061 is located at the end of the cavity 106, and its dimension along the positive X-axis direction is larger than that of the second portion 1062 along the positive X-axis direction. The plurality of grooves 105 are formed on surface S1, and a groove 105 is formed between adjacent wire grids 104, with the opening of the groove 105 facing the cavity 106, i.e., facing the positive Z-axis direction.
[0071] In some embodiments, the depth difference between any two grooves 105 may be less than or equal to 15% of the depth of the groove 105 (e.g., the average depth of each groove 105). For example, the depth difference between any two grooves 105 may be 1%, 5%, 8%, 10%, or 15% of the depth of the groove 105, etc., to improve the depth consistency of the grooves 105.
[0072] Referring again to Figure 4, and considering the structure of the wire grid polarizer 30 described above, it can be understood that during the etching process to form the groove 105, the reactive gas 40 needs to contact the substrate 101 via the cavity 106. The arrows within the cavity 106 in Figure 4 indicate the flow direction of the reactive gas 40. Specifically, since the second part 1062 is located at the top of the cavity 106, the reactive gas 40 will first enter the second part 1062 along the negative Z-axis, and then enter the first part 1061. When it reaches the bottom of the cavity 106, it contacts the surface S1, thereby etching the substrate 101 and ultimately obtaining the groove 105. During the etching process, the reactive gas 40 will continuously flow into the cavity 106. Therefore, after contacting the bottom of the cavity 106, a portion of the reactive gas 40 that does not have time to react with the substrate 101 will overflow from the cavity 106 along the positive Z-axis. In the structure of the aforementioned wire grid polarizer 30, since the dimension of the first portion 1061 along the positive X-axis is larger than the dimension of the second portion 1062 along the positive X-axis, that is, in the cavity 106, the width of the first portion 1061 is greater than the width of the second portion 1062. Thus, before the reactive gas 40 overflows the cavity 106, it is obstructed by the narrower second portion 1062, causing it to flow back into the first portion 1061 in the reverse direction (along the negative Z-axis), thereby filling the first portion 1061 with reactive gas 40. At this time, the first portion 1061 can be considered as a return cavity for the reactive gas 40, allowing the reactive gas 40 to make more sufficient contact with the surface S1, achieving uniform etching of different grooves 105. Furthermore, due to the formation of the aforementioned return cavity, sufficient contact between the reactive gas 40 and the substrate 101 can be achieved during the etching process without applying a bias voltage to the reactive gas 40. Therefore, it can also avoid uneven or excessive etching of the groove 105 due to deviations in the bias voltage value, thereby improving the depth consistency of the groove 105.
[0073] Understandably, the structure of the aforementioned wire-grid polarizer 30 can also improve its extinction ratio. The extinction ratio refers to the ratio of the transmittance of horizontally polarized light to the transmittance of vertically polarized light in the wire-grid polarizer 30. A higher extinction ratio indicates higher transmittance of horizontally polarized light and lower transmittance of vertically polarized light, resulting in a stronger ability of the wire-grid polarizer 30 to separate light of different polarization states and better optical performance. Therefore, because the structure of the aforementioned wire-grid polarizer 30 can improve the depth uniformity of the groove 105, the depth deviation of the groove 105 is smaller and closer to the design size (e.g., 20 nm), thereby improving the transmittance of the wire-grid polarizer 30 for horizontally polarized light and its overall extinction ratio.
[0074] Referring again to Figure 4, the wire grid body 104 may include a first wire grid portion 1041 and a second wire grid portion 1042 connected to each other. A first portion 1061 of the cavity 106 is located between adjacent first wire grid portions 1041, and a second portion 1062 of the cavity 106 is located between adjacent second wire grid portions 1042. It can be understood that since the dimension of the first portion 1061 along the positive X-axis is larger than the dimension of the second portion 1062 along the positive X-axis, correspondingly, the dimension of the first wire grid portion 1041 along the positive X-axis is smaller than the dimension of the second wire grid portion 1042 along the positive X-axis.
[0075] For example, the dimension of the second wire grid portion 1042 in the positive Z-axis direction is less than or equal to the dimension of the first wire grid portion 1041 in the positive Z-axis direction, that is, the proportion of the dimension of the second wire grid portion 1042 in the positive Z-axis direction to the dimension of the wire grid body 104 in the positive Z-axis direction is less than or equal to 50%. This allows the narrower first wire grid portion 1041 to occupy a larger proportion of the entire wire grid body 104, thereby keeping the resistance of the wire grid body 104 at a lower value and reducing the power consumption of the wire grid polarizer 30. Furthermore, during current transmission, the narrower first wire grid portion 1041 leads to reduced signal attenuation or distortion, thereby improving the depth uniformity of the groove 105 while ensuring the transmission quality of the optical signal (i.e., incident light) and other related optical performance of the wire grid body 104.
[0076] Referring again to Figure 4, the side surface of the second grid portion 1042 can be an arc surface, including a surface facing the cavity 106. Thus, due to the higher surface smoothness of the arc surface, the reactant gas 40 can more smoothly enter the first portion 1061 of the cavity 106, thereby facilitating the formation of backflow in the first portion 1061 and improving the etching uniformity and depth consistency of the groove 105. It should be noted that in some other embodiments, the side surface of the second grid portion 1042 can also be other shapes, such as a plane, etc. This application does not impose any limitations on the surface shape of the second grid portion 1042.
[0077] Referring again to Figure 4, exemplarily, the dimension of the wire gate 104 along the positive Z-axis, i.e., its height, can be 120 nm to 200 nm. For example, the height of the wire gate 104 can be 120 nm, 130 nm, 150 nm, 160 nm, 180 nm, or 200 nm, etc. It should be noted that this application does not impose any limitation on the height of the wire gate 104, and those skilled in the art can choose other dimensions according to actual needs.
[0078] Referring again to Figure 4, exemplarily, the dimension (width) of the first line gate portion 1041 along the positive X-axis can be 50 nm to 80 nm; the dimension (width) of the second line gate portion 1042 along the positive X-axis can be 70 nm to 90 nm. For example, the width of the first line gate portion 1041 can be 50 nm, 60 nm, 70 nm, or 80 nm, etc., and the width of the second line gate portion 1042 can be 70 nm, 80 nm, or 90 nm, etc. In other embodiments of this application, the width of the second line gate portion 1042 can also be 110% to 140% of the width of the first line gate portion 1041. It should be noted that this application does not impose any limitations on the specific dimensions of the first line gate portion 1041 and the second line gate portion 1042, and those skilled in the art can select other dimensions according to actual needs.
[0079] Referring again to Figure 4, the period P2 of the wire grid polarizer 30 is the sum of the distance between adjacent wire grid bodies 104 along the X-axis and the width (i.e., the dimension along the X-axis) of one wire grid body 104. For example, the period P2 can be 100 nm to 150 nm, such as 100 nm, 110 nm, 130 nm, or 150 nm. It should be noted that this application does not impose any limitations on the specific dimensions of the period P2 of the wire grid polarizer 30; those skilled in the art can select other dimensions according to actual needs.
[0080] Referring again to Figure 4, the wire grid 104 can be an integrally molded structure, meaning it is manufactured in one piece using a single molding method to improve its quality and durability. Furthermore, the material of the wire grid 104 can be an aluminum-copper alloy (AlCu) or metallic aluminum (Al), or other metallic materials. In some embodiments, the material of the wire grid 104 is an aluminum-copper alloy, and the proportion of copper (Cu) in the wire grid 104 can be 0.5%. It should be noted that this application does not impose any limitations on the material or material proportion of the wire grid 104.
[0081] Referring again to Figure 4, the depth of the groove 105 can be, for example, 5 nm to 50 nm. For instance, the depth of the groove 105 can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, or 50 nm, etc.
[0082] Exemplarily, the cross-sectional shape of the groove 105 can be one of a rectangle, a square, a semicircle, or a triangle, and the cross-section of the groove 105 is parallel to the positive X-axis direction and parallel to the positive Z-axis direction. For example, in some embodiments, referring to FIG4, the cross-sectional shape of the groove 105 is rectangular; in other embodiments, referring to FIG5, FIG5 shows a cross-sectional schematic diagram of another wire grid polarizer 30, and the cross-sectional shape of the groove 105 is triangular. It should be noted that this application does not impose any limitation on the cross-sectional shape of the groove 105, and those skilled in the art can also choose other shapes according to actual needs.
[0083] Referring again to Figure 4, the substrate 101 can be, by way of example, a material with high light transmittance, such as glass. The thickness of the substrate 101 (the dimension along the Z-axis) can be 0.7 mm to 1.5 mm. It should be noted that this application does not impose any limitations on the material, thickness, or shape of the substrate 101, and those skilled in the art can select other materials and thicknesses according to actual needs.
[0084] Additionally, it should be noted that the only difference between the wire grid polarizer 30 shown in Figure 5 and the wire grid polarizer 30 shown in Figure 4 is the cross-sectional shape of the groove 105; all other structures are identical. Therefore, the other structures of the wire grid polarizer 30 shown in Figure 5 can be referred to the description in the related embodiments of Figure 4 above, and will not be repeated here.
[0085] Another embodiment of the wire grid polarizer of this application will be described in detail below with reference to FIG6.
[0086] Figure 6 shows a cross-sectional schematic diagram of another type of wire-grid polarizer 30, specifically a cross-sectional schematic diagram of the portion of the wire-grid polarizer 30 parallel to the XZ plane. The wire-grid polarizer 30 shown in Figure 6 differs from the wire-grid polarizer 30 shown in Figure 4 only in that the cavity 106 also includes a third portion 1063. The second portion 1062 and the third portion 1063 are connected sequentially along the positive Z-axis, and the dimension of the third portion 1063 along the positive X-axis is larger than the dimension of the second portion 1062 along the positive X-axis. Thus, when the reactant gas is introduced into the cavity 106, it will first enter the wider third portion 1063, allowing the reactant gas to enter the cavity 106 more smoothly and improving the efficiency of reactant gas introduction.
[0087] Referring again to Figure 6, correspondingly, the wire grid body 104 also includes a third wire grid portion 1043, which is connected to the second wire grid portion 1042. A third portion 1063 is located between adjacent third wire grid portions 1043. It can be understood that since the dimension of the third portion 1063 along the positive X-axis is larger than the dimension of the second portion 1062 along the positive X-axis, correspondingly, the dimension of the third wire grid portion 1043 along the positive X-axis is smaller than the dimension of the second wire grid portion 1042 along the positive X-axis.
[0088] For example, the dimension of the third line gate portion 1043 along the positive Z-axis, i.e., its width, can be 50nm to 80nm. For instance, the width of the third line gate portion 1043 can be 50nm, 60nm, 70nm, or 80nm, etc. It should be noted that this application does not impose any limitations on the specific dimensions of the third line gate portion 1043, and those skilled in the art can select other dimensions according to actual needs.
[0089] Referring again to Figure 6, exemplarily, the dimension of the second wire grid portion 1042 in the positive Z-axis direction is less than or equal to the sum of the dimensions of the first wire grid portion 1041 and the third wire grid portion 1043 in the positive Z-axis direction. That is, the proportion of the dimension of the second wire grid portion 1042 in the positive Z-axis direction to the dimension of the wire grid body 104 in the positive Z-axis direction is less than or equal to 50%. Thus, as described above, the narrower first wire grid portion 1041 occupies a larger proportion of the entire wire grid body 104, thereby ensuring signal transmission quality and other related optical performance of the wire grid body 104.
[0090] It should be noted that the other structures and features of the wire grid polarizer 30 shown in Figure 6 are the same as those of the wire grid polarizer 30 shown in Figure 4. Therefore, the other structures in Figure 6 can be referred to the description in the relevant embodiments of Figure 4 above, and will not be repeated here. In addition, Figure 7 shows a cross-sectional schematic diagram of another type of wire grid polarizer 30. The only difference between the wire grid polarizer 30 shown in Figure 7 and the wire grid polarizer 30 shown in Figure 6 is the cross-sectional shape of the groove 105. Specifically, the cross-sectional shape of the groove 105 in Figure 6 is rectangular, while the cross-sectional shape of the groove 105 in Figure 7 is triangular; all other structures are the same. Therefore, the other structures in Figure 7 can be referred to the description in the relevant embodiments of Figure 6 above, and will not be repeated here.
[0091] Another embodiment of the wire grid polarizer of this application will be described in detail below with reference to Figure 8.
[0092] Figure 8 shows a cross-sectional schematic diagram of another type of wire-grid polarizer 30, specifically a cross-sectional schematic diagram of the portion of the wire-grid polarizer 30 parallel to the XZ plane. The only difference between the wire-grid polarizer 30 shown in Figure 8 and the wire-grid polarizer 30 shown in Figure 4 is that the wire-grid polarizer 30 also includes a transparent layer 107, which is located on the surface of the wire-grid body 104 facing the positive Z-axis (i.e., the upper surface of the wire-grid body 104). Thus, the transparent layer 107 provides a physical barrier for the wire-grid body 104, protecting the upper surface of the wire-grid body 104 from external environmental factors (such as contamination, mechanical damage, etc.). Furthermore, due to the high transmittance of the transparent layer, it will not interfere with the incident light, thus protecting the wire-grid body 104 without affecting the optical performance of the wire-grid polarizer 30.
[0093] Referring again to Figure 8, the surface of the transparent layer 107 facing the positive Z-axis can be curved. This curved surface allows for adjustment of the incident light angle, concentrating the incident light onto the lower wire grid 104, further improving the transmittance of the wire grid polarizer 30. Furthermore, the curved surface of the transparent layer 107 reduces deflection or distortion of the incident light when it strikes the upper surface of the wire grid 104, thereby better matching the propagation path of the incident light and reducing changes in the refraction angle, thus reducing distortion. It should be noted that in some other embodiments, the surface of the transparent layer 107 facing the positive Z-axis can also be other shapes, such as a plane. This application does not impose any limitations on the shape of the surface of the transparent layer 107 facing the positive Z-axis.
[0094] For example, the thickness of the transparent layer 107 (i.e., its dimension in the Z-axis direction) can be 4nm to 10nm. For instance, the thickness of the transparent layer 107 can be 4nm, 6nm, 8nm, or 10nm, etc. It should be noted that this application does not impose any limitations on the thickness of the transparent layer 107.
[0095] For example, the material of the transparent layer 107 can be a light-transmitting material such as silicon dioxide (SiO2). It should be noted that this application does not impose any restrictions on the material of the transparent layer 107.
[0096] Furthermore, Figures 9 to 11 show cross-sectional schematic diagrams of three different wire-grid polarizers 30. Figure 9 shows a structure with the aforementioned transparent layer 107 added to the wire-grid polarizer 30 shown in Figure 5; Figure 10 shows a structure with the aforementioned transparent layer 107 added to the wire-grid polarizer 30 shown in Figure 6; and Figure 11 shows a structure with the aforementioned transparent layer 107 added to the wire-grid polarizer 30 shown in Figure 7. The other structures in Figures 9, 10, and 11 are the same as those in Figures 5, 6, and 7, respectively. Therefore, the other structures in Figures 9, 10, and 11 can be referred to the descriptions in the embodiments related to Figures 5, 6, and 7, and will not be repeated here.
[0097] The performance parameters of the wire grid polarizer of this application will be described in detail below with reference to Figure 12.
[0098] Figure 12(a) shows a cross-sectional schematic diagram of a wire grid polarizer 10, which can be an exemplary structure of the wire grid polarizer 10 in Figure 1; Figure 12(b) shows a cross-sectional schematic diagram of a wire grid polarizer 20, which can be an exemplary structure of the wire grid polarizer 20 in Figure 2; Figure 12(c) shows a cross-sectional schematic diagram of a wire grid polarizer 30, which can be an exemplary structure of the wire grid polarizer 10 in Figure 4; Figure 12(d) shows the relevant performance parameters of the wire grid polarizer 10, the wire grid polarizer 20 and the wire grid polarizer 30.
[0099] As mentioned above, the specific structures of the wire grating polarizers 10, 20, and 30 can be referred to the relevant structural descriptions in Figures 1, 2, and 4, respectively, and will not be repeated here. Referring to Figure 12(d), it can be seen that due to the aforementioned groove consistency problem, the transmittance and extinction ratio of the wire grating polarizer 20 differ significantly between ideal and actual conditions. Compared to the actual wire grating polarizer 20, the transmittance and extinction ratio of the wire grating polarizer 30 in this application are improved when the incident light wavelength is 450 nm, and the extinction ratio of the wire grating polarizer 30 in this application is improved when the incident light wavelengths are 550 nm and 650 nm. Therefore, it can be seen that by improving the consistency of the groove 105, this application can improve the overall extinction ratio of the wire grating polarizer 30, that is, improve the ability of the wire grating polarizer 30 to separate light of different polarization states, thereby improving the optical performance of the grating polarizer 30.
[0100] In some embodiments, this application also provides a display device, which includes a light-emitting module and a linear grid polarizer described in the embodiments of this application. The light-emitting module is used to provide incident light to the linear grid polarizer. It is understood that a detailed description of the display device can be found in the above-mentioned embodiments, and will not be repeated here.
[0101] In some embodiments, this application also provides an electronic device, which includes a housing and a display device described in the embodiments of this application, wherein the display device is located within the housing. It is understood that a detailed description of the electronic device can be found in the foregoing related embodiments, and will not be repeated here.
[0102] The following describes in detail, with reference to Figure 13, a method for fabricating a linear grating polarizer according to this application.
[0103] Figure 13 shows a schematic flowchart of a method for fabricating a wire grating polarizer. Specifically, this method can be used to fabricate the wire grating polarizer 30 described in the embodiments shown in Figure 4 or Figure 5. Referring to Figure 13 and in conjunction with Figures 4 and 5, the method for fabricating the wire grating polarizer includes:
[0104] S11: Provide a substrate 101, which has a surface S1 facing the positive Z-axis direction.
[0105] The relevant structure of the substrate 101 can be referred to the description in the above embodiments, and will not be repeated here.
[0106] S12: A plurality of wire grids 104 are formed on surface S1 at intervals along the positive X-axis direction, wherein a cavity 106 is formed between adjacent wire grids 104. The cavity 106 includes a first part 1061 and a second part 1062 connected sequentially along the positive Z-axis direction. The first part 1061 is located at the end of the cavity 106, and the dimension of the first part 1061 along the positive X-axis direction is larger than the dimension of the second part 1062 along the positive X-axis direction.
[0107] In some embodiments, the wire gate 104 can be formed by a deposition process. Specifically, aluminum-copper alloy grains can be deposited on the substrate 101 by a vapor deposition process, followed by patterned etching to form a plurality of wire gates 104 spaced apart along the positive X-axis. Furthermore, the specific structure of the wire gate 104 can be referred to the relevant descriptions in the above embodiments, and will not be repeated here. It should be noted that the wire gate 104 can also be formed by other processes, and this application does not impose any limitations on the fabrication process of the wire gate 104.
[0108] S13: With a bias voltage less than or equal to 0.1 volts (V), a reactive gas 40 is introduced into the cavity 106, and the surface S1 between adjacent grid bodies 104 is etched based on the reactive gas 40 to form a plurality of grooves 105. Among them, a groove 105 is formed between adjacent grid bodies 104, and the opening of the groove 105 faces the cavity 106.
[0109] In some embodiments, the bias voltage can be 0V, 0.001V, 0.01V, or 0.1V, etc.
[0110] It is understandable that, continuing to refer to Figure 4, during the etching process to form the groove 105, the reactive gas 40 is introduced into the cavity 1062 along the negative Z-axis. Specifically, since the second part 1062 is located at the top of the cavity 106, the reactive gas 40 is first introduced into the second part 1062, and then into the first part 1061. When it reaches the bottom of the cavity 106, it contacts the surface S1, thereby etching the substrate 101 and finally obtaining the groove 105. Since the reactive gas 40 is continuously introduced into the cavity 106, after contacting the bottom of the cavity 106, a portion of the reactive gas 40 that does not have time to react with the substrate 101 will overflow from the cavity 106 along the positive Z-axis. In the structure of the wire grid polarizer 30 described above, since the dimension of the first part 1061 along the positive X-axis is larger than the dimension of the second part 1062 along the positive X-axis, that is, in the cavity 106, the width of the first part 1061 is larger than the width of the second part 1062.
[0111] Thus, before the reactive gas 40 overflows from the cavity 106, it is obstructed by the narrower second portion 1062, causing it to flow back into the first portion 1061. At this point, the first portion 1061 can be considered a reflux cavity, filled with the reactive gas 40, meaning the bottom of the cavity 106 is filled with the reactive gas 40. This allows the reactive gas 40 to make more thorough contact with the surface S1, improving the etching uniformity of different grooves 105. Furthermore, with the reflux cavity in place, the applied bias voltage can be less than or equal to 0.1V, or even none at all. Therefore, it can also avoid uneven etching or over-etching caused by deviations in the bias voltage value, thereby improving the depth consistency of the grooves 105.
[0112] In some other embodiments, referring to Figures 6 and 7, the cavity 106 may further include a third part 1063, wherein the second part 1062 and the third part 1063 are connected sequentially along the positive Z-axis, and the dimension of the third part 1063 along the positive X-axis is larger than the dimension of the second part 1062 along the positive X-axis. The specific structure of the third part 1063 can be referred to the relevant descriptions in the above embodiments, and will not be repeated here.
[0113] In some other embodiments, referring to Figures 8 to 12, before forming the groove 105 in S13, and after forming the wire grid 104 in S12, or after forming multiple grooves 105 in S13, the process may further include:
[0114] S14: A transparent layer 107 is formed on the surface of the wire grid 104 facing the positive Z-axis direction.
[0115] The transparent layer 107 can be formed on the wire gate 104 by deposition or other processes. The specific structure of the transparent layer 107 can be referred to the relevant description in the above embodiments, and will not be repeated here.
[0116] The specific embodiments described above illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with some embodiments, this does not mean that the features of this application are limited to this embodiment. On the contrary, the purpose of describing the application in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of this application. This application may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details have been omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.
[0117] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "set," "install," "connect," and "fit" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0118] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.
Claims
1. A wire grid polarizer, characterized in that, include: Substrate having a first surface facing a first direction; Multiple wire grids are located on the first surface and spaced apart along the second direction. A cavity is formed between adjacent wire grids. The cavity includes a first part and a second part connected sequentially along the first direction. The first part is located at the end of the cavity. The dimension of the first part along the second direction is larger than the dimension of the second part along the second direction. The first direction and the second direction are perpendicular. Multiple grooves are formed on the first surface, with one groove formed between adjacent wire grids, and the opening of the groove facing the cavity.
2. The wire grid polarizer according to claim 1, characterized in that, The depth difference between any two of the grooves is less than or equal to 15% of the groove depth.
3. The wire grid polarizer according to claim 1, characterized in that, The wire grid body includes a first wire grid portion and a second wire grid portion that are connected to each other. The first portion is located between adjacent first wire grid portions, and the second portion is located between adjacent second wire grid portions. The size of the second wire grid portion in the first direction is less than or equal to the size of the first wire grid portion in the first direction.
4. The wire grid polarizer according to claim 3, characterized in that, The surface of the second wire grid portion facing the second part is an arc surface.
5. The wire grid polarizer according to claim 3, characterized in that, The first line gate portion has a dimension of 50nm to 80nm along the second direction, and the second line gate portion has a dimension of 70nm to 90nm along the second direction.
6. The wire grid polarizer according to claim 3, characterized in that, The cavity further includes a third part, the second part and the third part are connected sequentially along the first direction, and the dimension of the third part along the second direction is greater than the dimension of the second part along the second direction.
7. The wire grid polarizer according to claim 6, characterized in that, The line grid body further includes a third line grid portion, which is connected to the second line grid portion. The third portion is located between adjacent third line grid portions, and the size of the third line grid portion along the second direction is 50nm to 80nm.
8. The wire grid polarizer according to claim 7, characterized in that, The size of the second wire grid portion in the first direction is less than or equal to the sum of the sizes of the first wire grid portion and the third wire grid portion in the first direction.
9. The wire grid polarizer according to claim 1, characterized in that, The depth of the groove is 5nm to 50nm.
10. The wire grid polarizer according to claim 1, characterized in that, The cross-sectional shape of the groove is one of a rectangle, a square, a semicircle, or a triangle, and the cross-section is parallel to the first direction and parallel to the second direction.
11. The wire grid polarizer according to any one of claims 1 to 10, characterized in that, The wire grid polarizer further includes a transparent layer located on the surface of the wire grid body facing the first direction.
12. The wire grid polarizer according to claim 11, characterized in that, The surface of the transparent layer facing the first direction is curved.
13. A display device, characterized in that, It includes a light-emitting module and a wire grid polarizer as described in any one of claims 1 to 12, wherein the light-emitting module is used to provide incident light to the wire grid polarizer.
14. An electronic device, characterized in that, It includes a housing and a display device as described in claim 13, wherein the display device is located within the housing.
15. A method for fabricating a linear grid polarizer, characterized in that, include: A substrate is provided, the substrate having a first surface facing a first direction; A plurality of wire grids are formed on the first surface at intervals along a second direction, wherein a cavity is formed between adjacent wire grids, the cavity comprising a first part and a second part connected sequentially along the first direction, the first part being located at the end of the cavity, the dimension of the first part along the second direction being greater than the dimension of the second part along the second direction, and the first direction being perpendicular to the second direction; The first surface is etched to form a plurality of grooves, and one of the grooves is formed between adjacent wire grids, the opening of the groove facing the cavity.
16. The method according to claim 15, characterized in that, The etching of the first surface to form a plurality of grooves includes: A reactive gas is introduced into the cavity, and the first surface between adjacent grid bodies is etched based on the reactive gas to form a plurality of grooves.
17. The method according to claim 16, characterized in that, The process of introducing a reactive gas into the cavity includes: When the bias voltage is less than or equal to 0.1V, the reactive gas is introduced into the cavity.