Lens assembly, display module and electronic device
By adjusting the refractive index of the semi-transparent and semi-reflective film in the lens assembly, the P-polarization state and S-polarization state of circularly polarized light are made to be evenly split, thus solving the ghosting problem caused by low circular polarization and improving the imaging effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING ZITIAO NETWORK TECH CO LTD
- Filing Date
- 2023-07-07
- Publication Date
- 2026-05-19
AI Technical Summary
In ultra-short focal length optical folding paths, the low circular polarization of circularly polarized light leads to a reduction in the proportion of useful light, resulting in ghosting interference imaging effects, which is particularly noticeable when the screen size is reduced.
By adjusting the refractive index of the semi-transparent and semi-reflective film using a modulation thin film layer and a dielectric thin film layer in the lens assembly, the P-polarization state and S-polarization state of circularly polarized light are more uniformly split, maintaining the circular polarization state of the circularly polarized light and reducing the influence of stray light.
It improves the circular polarization of circularly polarized light, reduces ghosting, and enhances imaging performance.
Smart Images
Figure CN119270395B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of display technology, and in particular to a lens assembly, a display module, and an electronic device. Background Technology
[0002] Among related technologies, the pancake optical path scheme for ultra-short focal length optics has become the development and evolution direction of consumer-grade virtual reality optics due to its relatively small field of view, significant advantages in device lightweighting and portability. In virtual reality devices based on the pancake optical scheme, after the image source enters the beam splitter, the light is refracted multiple times between the lenses in the lens group before finally exiting and entering the human eye.
[0003] In the optical path of a lens group, "useful" light is the light that effectively follows the complete folded optical path designed by the lens to form an image, while "harmful" light is the light that does not follow the complete folded optical path but reaches the human eye. This "harmful" light does not participate in image formation but instead acts as stray light, reducing contrast and interfering with normal viewing as ghosting. The circular polarization of circularly polarized light in the optical path is a crucial indicator for ensuring the proportion of "useful" light. Specifically, the lower the circular polarization of circularly polarized light in the optical path, the lower the proportion of "useful" light; conversely, the higher the circular polarization of circularly polarized light in the optical path, the higher the proportion of "useful" light.
[0004] When the screen size is significantly reduced, a considerable portion of the light emitted from the screen enters the lens group at a relatively large angle. Due to the basic properties of the beam-splitting material, the incident light from the screen undergoes significant polarization and beam splitting when passing through the beam-splitting film on the lens. This significantly reduces circular polarization, resulting in severe ghosting and poor image quality. Summary of the Invention
[0005] This application provides a lens assembly, a display module, and an electronic device.
[0006] An embodiment of this application provides a lens assembly including a first lens and a semi-transparent, semi-reflective coating. The first lens includes a first surface and a second surface facing away from each other, and the semi-transparent, semi-reflective coating is disposed on the first surface of the first lens. The semi-transparent, semi-reflective coating includes a modulation thin film layer and a dielectric thin film layer. The modulation thin film layer is disposed on the first surface of the first lens, and the dielectric thin film layer is disposed on the side of the modulation thin film layer away from the first lens. The dielectric thin film layer and the modulation thin film layer are used to cooperate in adjusting the refractive index of the semi-transparent, semi-reflective coating so that circularly polarized light incident on the semi-transparent, semi-reflective coating at different incident angles remains circularly polarized light after entering the first lens.
[0007] In some embodiments, the dielectric thin film layer and the modulation thin film layer are used to control the difference between the refractive index of the P-polarized state and the refractive index of the S-polarized state of the circularly polarized light transmitted and reflected by the semi-transparent and semi-reflective film, so that the difference in the amount of light splitting between the P-polarized state and the S-polarized state of the circularly polarized light entering therein is less than a preset threshold.
[0008] In some embodiments, the modulation film layer includes a plurality of columnar modulation units arranged side by side on a first surface of the first lens, wherein the major axis of each modulation unit is inclined relative to the optical axis of the first lens.
[0009] In some embodiments, the intersection of the major axis of the modulation unit and the first surface of the first lens is taken as the incident point. The normal of the incident point on the first surface of the first lens forms an angle with the major axis of the modulation unit. The angle is related to the radius of curvature of the first lens, the axial distance from the incident point to the optical axis of the first lens, the distance from the light source emitting the circularly polarized light on the optical axis of the first lens to the first surface of the first lens, and the maximum length of the circularly polarized light that the light source can emit in the direction perpendicular to the optical axis of the first lens.
[0010] In some implementations, the included angle ranges from [5° to 80°].
[0011] In some embodiments, the thickness of the dielectric thin film layer is in the range of [20nm, 2000nm].
[0012] In some embodiments, the thickness of the modulation thin film layer is in the range of [20nm, 2000nm].
[0013] In some embodiments, the material of the dielectric thin film layer is an oxide.
[0014] In some embodiments, the material of the modulation thin film layer is an oxide or a metal.
[0015] In some embodiments, the material of the modulation thin film layer is metal, and the thickness of the modulation thin film layer ranges from [50nm, 2000nm].
[0016] In some embodiments, the lens assembly further includes a phase retardation film disposed on a second surface of the first lens, the phase retardation film being used to change the polarization state of light passing through the phase retardation film.
[0017] In some embodiments, the lens assembly further includes a second lens and a reflective polarizing film. The second lens includes a first surface and a second surface facing away from each other, with the first surface of the second lens facing the second surface of the first lens. The reflective polarizing film is disposed on the first surface of the second lens and is used to reflect linearly polarized light of the P-polarized state from the phase retardation film toward the phase retardation film and to transmit linearly polarized light of the S-polarized state from the phase retardation film.
[0018] An embodiment of this application provides a display module including a lens assembly and a display screen as described in any of the above embodiments, wherein the display screen is used to emit light to the lens assembly.
[0019] The electronic device provided in this application includes a body and a display module as described in the above embodiments, wherein the display module is combined with the body.
[0020] The lens assembly, display module, and electronic device of this application utilize a modulation thin film layer and a dielectric thin film layer to adjust the refractive index of a semi-transparent and semi-reflective film, thereby making the P-polarization state and S-polarization state of circularly polarized light more uniformly split. This ensures that the circularly polarized light passing through the semi-transparent and semi-reflective film maintains its circular polarization state, resulting in a higher circular polarization of the transmitted circularly polarized light. This reduces the influence of stray light on the propagation of subsequent light in the optical path, thereby reducing ghosting and improving imaging performance.
[0021] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0022] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein:
[0023] Figure 1 This is a schematic diagram of the structure of a display module according to certain embodiments of this application;
[0024] Figure 2 yes Figure 1 The diagram shows the relationship between the reflectivity of the lens assembly and the wavelength of light in the display module.
[0025] Figure 3 yes Figure 1 The diagram shown is a partial structural schematic of the display module.
[0026] Figure 4 yes Figure 3 Enlarged schematic diagram of section IV;
[0027] Figure 5 yes Figure 3 Enlarged diagram of section V;
[0028] Figure 6 This is a schematic diagram of the structure of an electronic device according to certain embodiments of this application;
[0029] Figure 7 This is a three-dimensional structural diagram of an electronic device according to certain embodiments of this application.
[0030] Explanation of key component symbols:
[0031] Lens assembly 10, first lens 12, first surface 120 of the first lens, second surface 122 of the first lens, semi-transparent and semi-reflective film 14, modulation thin film layer 140, modulation unit 1401, dielectric thin film layer 142, phase delay layer 16, second lens 18, first surface 180 of the second lens, second surface 182 of the second lens, reflective polarizing film 19.
[0032] 100 display modules, 20 display screens;
[0033] Electronic equipment 1000, main body 200. Detailed Implementation
[0034] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of this application, and should not be construed as limiting the embodiments of this application.
[0035] The following disclosure provides numerous different embodiments or examples for implementing various structures of the embodiments of this application. To simplify the disclosure of the embodiments of this application, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Reference numerals and / or reference letters may be repeated in different examples of the embodiments of this application; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Furthermore, the embodiments of this application provide examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0036] Virtual reality devices based on the pancake optical scheme of ultra-short focal length optical folding optical path have light sources that, after entering the beam splitter, are refracted multiple times between the lenses in the lens group before finally exiting and entering the human eye.
[0037] In the optical path of a lens group, "useful" light is the light that effectively follows the complete folded optical path designed by the lens to form an image, while "harmful" light is the light that does not follow the complete folded optical path but reaches the human eye. This "harmful" light does not participate in image formation but instead acts as stray light, reducing contrast and interfering with normal viewing as ghosting. The circular polarization of circularly polarized light in the optical path is a crucial indicator for ensuring the proportion of "useful" light. Specifically, the lower the circular polarization of circularly polarized light in the optical path, the lower the proportion of "useful" light; conversely, the higher the circular polarization of circularly polarized light in the optical path, the higher the proportion of "useful" light.
[0038] Circular polarization can be defined as the degree to which circularly polarized light is preserved on the outgoing side during a single transmission. When the incident light is circularly polarized, the outgoing light may contain circularly polarized light, elliptically polarized light, or both. The less circularly polarized light and the more elliptically polarized light in the outgoing light, the lower the circular polarization of the light; conversely, the more circularly polarized light and the less elliptically polarized light in the outgoing light, the higher the circular polarization of the light.
[0039] The Pancake optical scheme mainly consists of a beam splitter, a phase delay film, and a reflective polarizing film. The light source emits right-cricularly polarized (RCP) light. After passing through the beam splitter, 50% of the light is reflected, and 50% passes through. The transmitted RCP light then passes through the phase delay film and becomes P-linearly polarized light. This P-linearly polarized light reaches the reflective polarizing film, which reflects it back. The P-linearly polarized light then passes through the phase delay film a second time and becomes right-cricularly polarized again. It is then reflected by the beam splitter and becomes left-cricularly polarized (LCP). This left-cricularly polarized light passes through the phase delay film a third time and becomes S-linearly polarized light. The S-linearly polarized light reaches the reflective polarizing film and is transmitted, ultimately entering the human eye. In this process, the phase delay film is used to convert the polarization state of the light. To ensure that circularly polarized light passing through the phase delay plate is converted into linearly polarized light, it is necessary to ensure that all light incident on the phase delay plate is circularly polarized. However, when circularly polarized light passes through the beam splitter, due to the short distance between the light source and the beam splitter and the small size of the light source, the incident angle of the light rays entering the beam splitter is large. In this case, the circularly polarized light passing through the beam splitter becomes elliptically polarized light. Elliptically polarized light cannot be converted into linearly polarized light after passing through the phase delay plate, and therefore cannot be reflected by the reflective polarizing film. Instead, it becomes stray light propagating in the optical path. This stray light accumulates in the optical path between the lenses, producing shadows, ultimately resulting in ghosting in the image seen by the user and poor image quality. To solve this problem, this application provides a lens assembly 10 ( Figure 1 As shown), display device 100 Figure 6 (as shown) and electronic equipment ( Figure 7(As shown).
[0040] Please see Figure 1 The lens assembly 10 provided in this application includes a first lens 12 and a semi-transparent and semi-reflective film 14.
[0041] The first lens 12 includes a first surface 120 and a second surface 122 facing away from each other. The semi-transparent and semi-reflective coating 14 includes a modulation thin film layer 140 and a dielectric thin film layer 142. The modulation thin film layer 140 is disposed on the first surface 120 of the first lens 12, and the dielectric thin film layer 142 is disposed on the side of the modulation thin film layer 140 away from the first lens 12. The dielectric thin film layer 142 and the modulation thin film layer 140 are used to cooperate in adjusting the refractive index of the semi-transparent and semi-reflective coating 14 so that circularly polarized light incident on the semi-transparent and semi-reflective coating 14 at different incident angles remains circularly polarized light after entering the first lens 12.
[0042] The first lens 12 is an optical element made of a light-transmitting material (such as glass, plastic or crystal). It mainly uses the refraction of light to transmit light in the optical path of the lens assembly 10. The first lens 12 includes a first surface 120 and a second surface 122 that are opposite to each other.
[0043] The semi-transparent and semi-reflective film 14 is used to transmit circularly polarized light incident therein, and can reflect circularly polarized light from the second surface 122 of the first lens 12 into circularly polarized light with the opposite rotation direction.
[0044] A semi-transparent and semi-reflective coating 14 is disposed on the first surface 120 of the first lens 12. The semi-transparent and semi-reflective coating 14 includes a modulation thin film layer 140 and a dielectric thin film layer 142. The semi-transparent and semi-reflective coating 14 is configured by stacking the modulation thin film layer 140 and the dielectric thin film layer 142, which allows for control over the difference in refractive index between the modulation thin film layer 140 and the dielectric thin film layer 142. By adjusting the refractive index and film thickness of the modulation thin film layer 140 and the dielectric thin film layer 142, the beam splitting effect of the semi-transparent and semi-reflective coating 14 can be changed, that is, the circular polarization of circularly polarized light after transmission can be improved.
[0045] The lens assembly 10 described above uses the modulation thin film layer 140 and the dielectric thin film layer 142 to adjust the refractive index of the semi-transparent and semi-reflective film 14, thereby making the P-polarization state and S-polarization state of circularly polarized light more uniformly split, so that the circularly polarized light passing through the semi-transparent and semi-reflective film 14 remains in a circularly polarized state, and the circular polarization of the transmitted circularly polarized light is higher, reducing the influence of stray light on the propagation of subsequent light in the optical path, thereby reducing ghosting and improving the imaging effect.
[0046] In some embodiments, the dielectric thin film layer 142 and the modulation thin film layer 140 are used to control the difference between the refractive index of the P-polarized state and the refractive index of the S-polarized state of the circularly polarized light transmitted and reflected by the semi-transparent and semi-reflective film 14, so that the difference in the amount of light splitting between the P-polarized state and the S-polarized state of the circularly polarized light entering therein is less than a preset threshold.
[0047] Thus, by controlling the difference between the refractive index of the P-polarized state and the refractive index of the S-polarized state of circularly polarized light, the circular polarization of circularly polarized light can be made higher.
[0048] Specifically, the circularity of circularly polarized light is related to the difference between the refractive index of the P-polarized state and the refractive index of the S-polarized state. The dielectric thin film layer 142 and the modulation thin film layer 140 can ensure that the difference in the splitting amount of the P-polarized state and the S-polarized state of the circularly polarized light entering them is less than a preset threshold. Ideally, if the splitting amounts of the P-polarized state and the S-polarized state are equal, the circularity of the circularly polarized light can be optimized. The preset threshold can make the splitting amounts of the P-polarized state and the S-polarized state close to the ideal state, that is, the preset threshold can make the splitting amounts of the P-polarized state and the S-polarized state approximately equal. The preset threshold can be a reasonable range obtained from experiments or experience, and is not specifically limited here.
[0049] Please see Figure 2 , Figure 2 This diagram illustrates the relationship between the reflectivity of circularly polarized light and the wavelength of light on the semi-transparent and semi-reflective film 14. By adjusting the difference between the refractive indices of the P-polarized and S-polarized states of circularly polarized light in the semi-transparent and semi-reflective film 14, the dispersion of light between the P-polarized and S-polarized states becomes more uniform. A preset threshold is set at... Figure 2 The above reaction is the reflectance R. S and R P The smaller the distance between them, the higher the circular polarization of the circularly polarized light after passing through the semi-transparent and semi-reflective film 14.
[0050] Specifically, please refer to Figure 1 and Figure 3 In some embodiments, the modulation film layer 140 includes a plurality of columnar modulation units 1401, which are arranged side by side on the first surface 120 of the first lens 12, and the major axis of each modulation unit 1401 is inclined relative to the optical axis O of the first lens 12.
[0051] Thus, in the semi-transparent and semi-reflective film 14, the refractive index of the modulation film layer 140 is changed by the angle at which the major axis of each modulation unit 1401 is tilted relative to the optical axis O of the first lens 12, and in conjunction with the dielectric film layer 142, the polarization state of the incident light transmission portion is maintained.
[0052] Specifically, such as Figure 1 As shown, the optical axis of the first lens 12 is marked as O, and the major axis of the modulation unit 1401 is marked as C. The major axis C of the modulation unit 1401 is tilted relative to the optical axis O, thereby changing the refractive index of the modulation thin film layer 140 so that it forms a refractive angle difference with the refractive index of the dielectric thin film layer 142. This allows circularly polarized light incident on the semi-transparent and semi-reflective film 14 at different incident angles to remain circularly polarized light after entering the first lens 12.
[0053] In some embodiments, the intersection of the major axis of the modulation unit 1401 and the first surface 120 of the first lens 12 is used as the incident point. The normal of the incident point on the first surface 120 of the first lens 12 forms an angle with the major axis of the modulation unit 1401. The angle is related to the radius of curvature of the first lens 12, the axial distance from the incident point to the optical axis O of the first lens 12, the distance from the light source emitting circularly polarized light on the optical axis O of the first lens 12 to the first surface 120 of the first lens 12, and the maximum length of circularly polarized light that the light source can emit in the direction perpendicular to the optical axis O of the first lens 12.
[0054] Thus, in the lens assembly 10, as Figure 3 As shown, by drawing a tangent along the mirror direction of the first lens 12, the positional relationship between the lens assembly 10 and the light source is equivalent to a geometric relationship on a plane. Using the included angle, the radius of curvature of the first lens 12, the axial distance from the incident point to the optical axis O of the first lens 12, the distance from the light source emitting circularly polarized light on the optical axis O of the first lens 12 to the first surface 120 of the first lens 12, and the maximum length of circularly polarized light that the light source can emit in the direction perpendicular to the optical axis O of the first lens 12, the tilt angle between the major axis of the modulation unit 1401 and the optical axis O of the first lens 12 can be calculated and determined.
[0055] Specifically, such as Figures 3 to 5 As shown, the radius of curvature of the first lens 12 is R, the major axis of the modulation unit 1401 is C, the incident point is A, the tangent to the first surface 120 of the first lens 12 drawn through the incident point A is denoted as H, the normal to the first surface 120 of the first lens 12 is denoted as V, the distance from the light source emitting circularly polarized light on the optical axis O of the first lens 12 to the first surface 120 of the first lens 12 is L1, the maximum length of circularly polarized light that the light source can emit in the direction perpendicular to the optical axis O of the first lens 12 is L2, the perpendicular line drawn from the incident point A to the optical axis O is denoted as D, representing the on-axis distance from the incident point A to the optical axis O of the first lens 12, and denoted as 2D = L3. The incident angle of the incident ray is ∠α, the angle between the major axis C of the modulation unit 1401 and the normal V of the first surface 120 of the first lens 12 is denoted as ∠α', the complementary angle of ∠α is denoted as ∠β, and the angle between D and H is denoted as ∠γ. The value of ∠α will vary depending on the position of the incident point A on the first surface 120 of the first lens 12, such as... Figure 4 and Figure 5 As shown. When incident circularly polarized light is incident in the direction close to the optical axis O of the first lens 12, even if the refractive index of the modulation thin film layer 140 and the dielectric thin film layer 142 is the same, the circular polarization of the circularly polarized light passing through the semi-transparent and semi-reflective film 14 will be relatively high. Therefore, the closer to the optical axis O of the first lens 12, the smaller the incident angle of the circularly polarized light, that is, the smaller the value of ∠α'; correspondingly, the farther away from the optical axis O of the first lens 12, the larger the incident angle of the circularly polarized light, that is, the larger the value of ∠α'.
[0056] Since ∠α' is equal to the angle of reflection of the incident ray, we have ∠α=∠α'. ∠β is the complementary angle of ∠α, therefore, ∠β=90°-∠α.
[0057] Perform geometric calculations based on the above relationships:
[0058]
[0059]
[0060]
[0061] Through the above geometric derivation, it can be seen that given the distance L1 from the light source emitting circularly polarized light on the optical axis O of the first lens 12 to the first surface 120 of the first lens 12, the maximum length L2 of the circularly polarized light emitted by the light source in the direction perpendicular to the optical axis O of the first lens 12, the axial distance D from the incident point A to the optical axis O of the first lens 12, and the radius of curvature R of the first lens 12, the angle ∠α' between the major axis C of the modulation unit 1401 and the normal V of the first surface can be obtained. Based on ∠α', the first lens 12 is coated to obtain a modulation thin film layer 140 with a corresponding angle between the major axis C of the modulation unit 1401 and the normal V of the first surface 120 of the first lens 12, which can be used in conjunction with the dielectric thin film layer 142 to adjust the beam splitting effect of the semi-transparent and semi-reflective film 14.
[0062] In some implementations, the included angle ranges from [5° to 80°].
[0063] Thus, within this range, it is possible to maintain the effect of the semi-transparent and semi-reflective film 14 while keeping the size of the lens assembly 10 relatively small.
[0064] Specifically, in the above-mentioned lens assembly 10 used for display device 1000 ( Figure 6 or Figure 7In the case shown, based on the size requirements of the lens assembly 10, there are certain limitations on the relevant dimensions of the lens assembly 10. Therefore, considering the above-mentioned method for calculating the included angle and the size requirements of the lens assembly 10, the included angle ranges from [5°, 80°]. Furthermore, the included angle gradually increases from the direction closer to the optical axis O to the direction farther from the optical axis O. This allows the lens assembly 10 to have a smaller size while maintaining good imaging performance. When the included angle ∠α' is less than 5° or greater than 80°, it may result in the lens assembly 10 having the required imaging performance but a larger size, or a smaller size but a poorer imaging performance. Therefore, the included angle ranges from [5°, 80°]. For example, the included angle can be 5°, 10°, 20°, 30°, 40°, 45°, 50°, 60°, 70°, or 80°, or any other value within the range [5°, 80°].
[0065] In some embodiments, the thickness of the dielectric thin film layer 142 is in the range of [20nm, 2000nm].
[0066] In some embodiments, the thickness of the modulation thin film layer 140 is in the range of [20 nm, 2000 nm].
[0067] Thus, by selecting the thicknesses of the dielectric thin film layer 142 and the modulation thin film layer 140 within the range of values, the characteristics of the semi-transparent and semi-reflective film 14 can be guaranteed, and the overall size of the lens assembly 10 can be controlled.
[0068] Specifically, the dielectric thin film layer 142 and the modulation thin film layer 140 affect the reflectivity of the film through their material properties and film thickness, thereby affecting the performance of the semi-transparent and semi-reflective film 14. When incident circularly polarized light is incident on the film surface, there is a refraction angle difference between the dielectric thin film layer 142 and the modulation thin film layer 140. By controlling this refraction angle difference, the spectral splitting characteristics of the P-polarization state and the S-polarization state of the circularly polarized light can be controlled, making the spectral splitting of the P-polarization state and the S-polarization state of the circularly polarized light more uniform.
[0069] The thickness of the modulation thin film layer 140 ranges from [20nm to 2000nm]. For example, the thickness of the modulation thin film layer 140 can be 20nm, 50nm, 100nm, 300nm, 500nm, 1000nm, 1200nm, 1500nm, 1800nm, or 2000nm, or any other value within the range [20nm to 2000nm]. If the thickness of the modulation thin film layer 140 is less than 20nm, the processing is difficult, which may prevent the modulation unit 1401 of the modulation thin film layer 140 from being formed, or affect the refractive index of the modulation thin film layer 140 due to its small thickness. If the thickness of the modulation thin film layer 140 is greater than 2000nm, it may affect the refractive index of the modulation thin film layer 140 and the overall thickness of the first lens 12.
[0070] The thickness of the dielectric thin film layer 142 ranges from [20nm to 2000nm]. For example, the thickness of the dielectric thin film layer 142 can be 20nm, 50nm, 100nm, 300nm, 500nm, 1000nm, 1200nm, 1500nm, 1800nm, or 2000nm, or any other value within the range [20nm to 2000nm]. If the thickness of the dielectric thin film layer 142 is less than 20nm, the processing is difficult, which may prevent the modulation unit 1401 of the modulation thin film layer 140 from being formed, or affect the refractive index of the dielectric thin film layer 142 due to its small thickness. If the thickness of the dielectric thin film layer 142 is greater than 2000nm, it may affect the refractive index of the dielectric thin film layer 142 and the overall thickness of the first lens 12.
[0071] In some embodiments, the dielectric thin film layer 142 is made of an oxide.
[0072] In some embodiments, the material of the modulated thin film layer 140 is an oxide or a metal.
[0073] Thus, by utilizing the material properties of the dielectric thin film layer 142 and the modulation thin film layer 140, a semi-transparent and semi-reflective effect on incident light is achieved.
[0074] Specifically, the semi-transparent and semi-reflective coating 14 is typically applied to the first surface 120 of the first lens 12 using a coating process. In the coating material, an oxide or metal material capable of realizing the function of the semi-transparent and semi-reflective coating 14 is selected as the material for the dielectric thin film layer 142 and the modulation thin film layer 140, based on the refractive index of the coating material and the requirements of the processing technology.
[0075] In this design, the dielectric thin film layer 142 is made of oxide, and the modulation thin film layer 140 can be made of oxide or metal. When both the dielectric thin film layer 142 and the modulation thin film layer 140 are made of oxide, after processing, the dielectric thin film layer 142 and the modulation thin film layer 140 formed by the oxide material can bond more tightly to the first lens 12 and are less likely to fall off. The oxide can be any of the following materials: Al2O3, Bi2O3, CeO2, Cr2O3, HfO2, In2O3, MgO, MoO3, La2O3, Nd2O3, PbO, SiO2, Sm2O3, SnO2, Ta2O5, TiO2, Ti4O7, Ti3O5, Ti2O3, TiO, WO3, Y2O3, ZrO2, or ZnO.
[0076] In other embodiments, the modulated thin film layer 140 may be made of a metallic material, which may be any of the following materials: Ag, Au or Al.
[0077] In some embodiments, the material of the modulation thin film layer 140 is metal, and the thickness of the modulation thin film layer 140 ranges from [50nm, 2000nm].
[0078] Thus, by selecting a metallic material for the modulation thin film layer 140 and coordinating it with the oxide material of the dielectric thin film layer 142 to regulate the difference in refractive index, the spectral dispersive effect of the semi-transparent and semi-reflective film 14 can be better controlled.
[0079] Specifically, the material of the modulation thin film layer 140 can be a metallic material. Metallic materials have a greater difference in refractive index than oxide materials, and choosing a metallic material for the modulation thin film layer 140 allows for better compatibility with the oxide material of the dielectric thin film layer 142, thus controlling the difference in refractive index between the two. The thickness of the modulation thin film layer 140 ranges from [50nm to 2000nm]. For example, the thickness of the modulation thin film layer 140 can be 50nm, 100nm, 150nm, 300nm, 500nm, 1000nm, 1200nm, 1500nm, 1800nm, or 2000nm, or any other value within the range [50nm to 2000nm]. If the thickness of the modulation thin film layer 140 is less than 50nm, the processing is difficult, and it may be impossible to form the modulation thin film layer 140. If the thickness of the modulation thin film layer 140 is greater than 2000nm, it may affect the refractive index of the modulation thin film layer 140 and the overall thickness of the first lens 12.
[0080] In some embodiments, the lens assembly 10 further includes a phase retardation layer 16 disposed on the second surface 122 of the first lens 12, the phase retardation layer 16 being used to change the polarization state of light passing through the phase retardation layer 16.
[0081] In this way, the transmitted light can be converted between circularly polarized light and linearly polarized light.
[0082] Specifically, the phase retardation layer 16 refers to a device capable of converting the polarization state of light. The phase retardation layer 16 generates a relative phase delay between the two polarization components of polarized light whose vibration directions are perpendicular to each other, thereby changing the polarization characteristics of the light.
[0083] A phase retardation layer 16 is disposed on the second surface 122 of the first lens 12. The phase retardation layer 16 is used to change the polarization state of light in the folded optical path. For example, it can convert linearly polarized light into circularly polarized light, or circularly polarized light into linearly polarized light.
[0084] exist Figure 1 In the illustrated embodiment, the phase retardation layer 16 is a phase retardation film disposed on the second surface 122 of the first lens 12. In other embodiments, the phase retardation layer 16 may be a quarter-wave plate disposed on the side near the second surface 122 of the first lens 12.
[0085] In some embodiments, the lens assembly 10 further includes a second lens 18 and a reflective polarizing film 19.
[0086] The second lens 18 includes a first surface 180 and a second surface 182 facing away from each other. The first surface 180 of the second lens 18 faces the second surface 122 of the first lens 12. A reflective polarizing film 19 is disposed on the first surface 180 of the second lens 18. The reflective polarizing film 19 is used to reflect linearly polarized light of the P-polarized state from the phase retardation layer 16 toward the phase retardation layer 16 and to transmit linearly polarized light of the S-polarized state from the phase retardation layer 16.
[0087] Thus, the second lens 18 can reflect P-polarized light and transmit S-polarized light, ultimately causing the S-polarized light to be emitted.
[0088] Specifically, the second lens 18 is an optical element made of a light-transmitting material (such as glass, plastic or crystal), which mainly uses the refraction of light to refract light in the optical path of the lens assembly 10.
[0089] The reflective polarizing film 19 selectively transmits light. The reflective polarizing film 19 has a transmission axis; light rays with polarization directions parallel to the transmission axis can pass through the reflective polarizing film 19, while light rays with polarization directions perpendicular to the transmission axis can be reflected by the reflective polarizing film 19. In one embodiment, the reflective polarizing film 19 transmits S-polarized light and reflects P-polarized light, the polarization directions of which are perpendicular to those of the S-polarized light. That is, the polarization direction of the S-polarized light is parallel to the transmission axis of the reflective polarizing film 19, and the polarization direction of the P-polarized light is perpendicular to the transmission axis of the reflective polarizing film 19.
[0090] The lens assembly 10 also includes a second lens 18 and a reflective polarizing film 19. The second lens 18 includes a first surface 180 and a second surface 182 facing away from each other. The first surface 180 of the second lens 18 faces the second surface 122 of the first lens 12. The reflective polarizing film 19 is disposed on the first surface 180 of the second lens 18. The reflective polarizing film 19 is used to reflect the P-polarized light from the phase retardation layer 16 toward the phase retardation layer 16. After passing through the phase retardation layer 16, it becomes right-hand circularly polarized light. The right-hand circularly polarized light is reflected by the beam splitter and becomes left-hand circularly polarized light. The left-hand circularly polarized light passes through the phase retardation layer 16 for the third time and becomes S-polarized light. Finally, the reflective polarizing film 19 transmits the S-polarized light from the phase retardation layer 16.
[0091] In summary, the lens assembly 10 includes a first lens 12 and a second lens 18. The first lens 12 includes a first surface 120 and a second surface 122 that are opposite to each other. The second lens 18 includes a first surface 180 and a second surface 182 that are opposite to each other. The second lens 18 is disposed on the side where the second surface 122 of the first lens 12 is located. A semi-transparent and semi-reflective coating 14 is disposed on the first surface 120 of the first lens 12. A phase retardation layer 16 is disposed on the second surface 122 of the first lens 12. A reflective polarizing coating 19 is disposed on the second surface 182 of the second lens 18. The light source emits circularly polarized light. Based on the different incident angles of the circularly polarized light incident on the semi-transparent and semi-reflective film 14, the angle of the modulation unit 1401 of the modulation film layer 140 is controlled to change the refractive index of the modulation film layer 140, thereby controlling the refractive index difference between the dielectric film layer 142 and the modulation film layer 140. Ultimately, the spectral splitting characteristics of the P-polarization state and S-polarization state of the circularly polarized light transmitted on the semi-transparent and semi-reflective film 14 can be controlled, making the spectral splitting of the P-polarization state and S-polarization state of the circularly polarized light more uniform. This ensures the circular polarization of the circularly polarized light transmitted from the semi-transparent and semi-reflective film 14 at different angles, reduces the generation of elliptically polarized light, and further reduces the generation of stray light in the subsequent optical path, thus improving the imaging effect.
[0092] The display module 100 provided in this application includes a lens assembly 10 and a display screen 20 as described in any of the above embodiments, wherein the display screen 20 is used to emit light to the lens assembly 10.
[0093] Specifically, the display screen 20 serves as a light source, emitting light to the lens assembly 10. The display screen 20 can be one of the following: an organic light-emitting diode (OLED) display panel, a silicon-based OLED display panel, a micro-organic light-emitting diode (MicroOLED) display panel, a miniature light-emitting diode (Mini LED) display panel, a liquid crystal display panel, or a silicon-based liquid crystal display panel.
[0094] In one embodiment, the display screen 20 emits linearly polarized light, and the display module 100 may further include a quarter-wave plate disposed on the light emitting side of the display screen 20, which can convert the linearly polarized light emitted from the display screen 20 into circularly polarized light.
[0095] In other embodiments, the display screen 20 is configured to emit circularly polarized light, thereby eliminating the need for a quarter-wave plate in front of the display screen 20, which helps to simplify the structure of the display module 100 and reduce its size.
[0096] Please see Figure 6 and Figure 7 The electronic device 1000 provided in this application includes a main body 200 and a display module 100 as described in the above embodiments, wherein the display module 100 is combined with the main body 200.
[0097] The lens assembly 10, display module 100, and electronic device 1000 of this application utilize a modulation thin film layer 140 and a dielectric thin film layer 142 to adjust the refractive index of the semi-transparent and semi-reflective film 14, thereby making the P-polarization state and S-polarization state of circularly polarized light more uniformly split. This ensures that the circularly polarized light passing through the semi-transparent and semi-reflective film 14 maintains its circular polarization state, resulting in a higher circular polarization of the transmitted circularly polarized light. This reduces the influence of stray light on the propagation of subsequent light in the optical path, thereby reducing ghosting and improving the imaging effect.
[0098] Specifically, the electronic device 1000 can be a wearable electronic device, including but not limited to head-mounted displays, smart glasses, smartwatches, or wristbands.
[0099] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0100] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.
Claims
1. A lens assembly, characterized in that, include: A first lens, the first lens including a first surface and a second surface opposite to each other; and A semi-transparent and semi-reflective film is disposed on the first surface of the first lens. The semi-transparent and semi-reflective film includes a modulation film layer and a dielectric film layer. The modulation film layer is disposed on the first surface of the first lens, and the dielectric film layer is disposed on the side of the modulation film layer away from the first lens. The dielectric film layer and the modulation film layer are used to cooperate to adjust the refractive index of the semi-transparent and semi-reflective film so that circularly polarized light incident on the semi-transparent and semi-reflective film at different incident angles remains circularly polarized light after entering the first lens. The dielectric thin film layer and the modulation thin film layer are used to control the difference between the refractive index of the P-polarized state and the refractive index of the S-polarized state of the circularly polarized light transmitted and reflected by the semi-transparent and semi-reflective film, so that the difference in the amount of light splitting between the P-polarized state and the S-polarized state of the circularly polarized light entering it is less than a preset threshold.
2. The lens assembly according to claim 1, characterized in that, The modulation film layer includes a plurality of columnar modulation units, which are arranged side by side on the first surface of the first lens, and the major axis of each modulation unit is inclined relative to the optical axis of the first lens.
3. The lens assembly according to claim 2, characterized in that, The intersection of the major axis of the modulation unit and the first surface of the first lens is taken as the incident point. The normal of the incident point on the first surface of the first lens forms an angle with the major axis of the modulation unit. The angle is related to the radius of curvature of the first lens, the axial distance from the incident point to the optical axis of the first lens, the distance from the light source emitting the circularly polarized light on the optical axis of the first lens to the first surface of the first lens, and the maximum length of the circularly polarized light that the light source can emit in the direction perpendicular to the optical axis of the first lens.
4. The lens assembly according to claim 3, characterized in that, The included angle ranges from [5° to 80°].
5. The lens assembly according to any one of claims 1-4, characterized in that, The thickness of the dielectric thin film layer ranges from [20nm, 2000nm]; and / or, The thickness of the modulation thin film layer ranges from [20nm, 2000nm].
6. The lens assembly according to any one of claims 1-4, characterized in that, The material of the dielectric thin film layer is an oxide; and / or, The material of the modulation thin film layer is an oxide or a metal.
7. The lens assembly according to any one of claims 1-4, characterized in that, The material of the modulation film layer is metal, and the thickness of the modulation film layer ranges from [50nm, 2000nm].
8. The lens assembly according to any one of claims 1-4, characterized in that, The lens assembly further includes a phase retardation film disposed on the second surface of the first lens, the phase retardation film being used to change the polarization state of light passing through the phase retardation film.
9. The lens assembly according to claim 8, characterized in that, The lens assembly also includes: A second lens, comprising a first surface and a second surface facing away from each other, wherein the first surface of the second lens faces the second surface of the first lens; and A reflective polarizing film is disposed on a first surface of the second lens. The reflective polarizing film is used to reflect linearly polarized light of the P-polarized state from the phase retardation film toward the phase retardation film and to transmit linearly polarized light of the S-polarized state from the phase retardation film.
10. A display module, characterized in that, include: The lens assembly according to any one of claims 1-9; and A display screen for emitting light to the lens assembly.
11. An electronic device, characterized in that, include: ontology; and The display module of claim 10, wherein the display module is combined with the body.