Lens assembly, display module and electronic equipment

Abstract

The invention discloses a lens assembly, a display module and electronic equipment. The lens assembly comprises a first lens and a semi-transparent and semi-reflective film. The first lens comprises a first surface and a second surface which are opposite to each other, and the semi-transparent and semi-reflective film is arranged on the first surface. The semi-transparent and semi-reflective film comprises a modulation thin film layer and a dielectric thin film layer, the modulation thin film layer is arranged on the first face of the first lens, and the dielectric thin film layer is arranged on the side, away from the first lens, of the modulation thin film layer. The dielectric thin film layer and the modulation thin film layer are used for adjusting the refractive index of the semi-transparent and semi-reflective film in a matched mode so that circularly polarized light entering the semi-transparent and semi-reflective film at different incident angles can be kept to be circularly polarized light after entering the first lens. According to the lens assembly, the display module and the electronic equipment, after the circularly polarized light is incident and passes through the semi-transparent and semi-reflective film, the circular polarization state of the circularly polarized light passing through the semi-transparent and semi-reflective film can be kept, the circular polarization degree of the circularly polarized light passing through the semi-transparent and semi-reflective film is high, the influence of stray light on follow-up light propagation is reduced, and therefore ghosting is reduced, and the imaging effect is improved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a lens assembly, a display module and an electronic device. Background Art

[0002] In related technologies, the ultra-short-focus optical folded light path (Pancake) solution has gradually become the development and evolution direction of consumer-grade virtual reality optics due to its relatively small field of view, lightweight equipment, and significant portability advantages. In virtual reality devices based on the Pancake optical solution, after the image source enters the beam splitter, the light is folded back and forth between the lenses in the lens group for many times, and finally emitted into the human eye.

[0003] In the optical path of the lens group, "useful" light is light that effectively follows the complete folded optical path designed by the lens to form an image, and "harmful" light is light that reaches the human eye without following the complete folded optical path. These "harmful" lights do not participate in imaging, but act as stray light to reduce contrast and act as ghosts to interfere with normal viewing. Among them, the circular deflection of circularly polarized light in the optical path is an important indicator to ensure the proportion of "useful" light. Specifically, the lower the circular deflection of circularly polarized light in the optical path, the lower the proportion of "useful" light. Conversely, the higher the circular deflection 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 larger angle. Due to the basic characteristics of the spectroscopic material, when the incident light from the screen passes through the spectroscopic film on the lens, the light incident at a large angle will undergo significant polarization splitting, which significantly reduces the circular deflection, resulting in severe ghosting and poor imaging effects. Summary of the invention

[0005] Embodiments of the present application provide a lens assembly, a display module, and an electronic device.

[0006] A lens assembly provided in an embodiment of the present application includes a first lens and a semi-transparent and semi-reflective film. The first lens includes a first surface and a second surface opposite to each other, and the semi-transparent and semi-reflective film is arranged 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 arranged on the first surface of the first lens, and the dielectric film layer is arranged 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 in adjusting the refractive index of the semi-transparent and semi-reflective film so that the circularly polarized light incident on the semi-transparent and semi-reflective film at different incident angles remains as circularly polarized light after entering the first lens.

[0007] In some embodiments, the dielectric film layer and the modulating film layer are used to control the difference between the refractive index of the P polarization state and the refractive index of the S polarization state of the circularly polarized light transmitted and reflected by the semi-transparent and semi-reflective membrane, so that the difference in the splitting amount of the P polarization state and the S polarization 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, and the plurality of modulation units are arranged side by side on the first surface of the first lens, and the long axis of each of the modulation units 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 used as the incident point, and there is an angle between the normal of the incident point on the first surface of the first lens and the major axis of the modulation unit, and the angle is related to the curvature radius 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 can be emitted by the light source in a direction perpendicular to the optical axis of the first lens.

[0010] In some embodiments, the angle ranges from [5°, 80°].

[0011] In some embodiments, the thickness of the dielectric thin film layer ranges from [20 nm to 2000 nm].

[0012] In some embodiments, the thickness of the modulated thin film layer ranges from [20 nm to 2000 nm].

[0013] In some embodiments, the material of the dielectric film layer is oxide.

[0014] In some embodiments, the material of the modulation thin film layer is oxide or 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 [50 nm to 2000 nm].

[0016] In some embodiments, the lens assembly further includes a phase delay film, which is disposed on the second surface of the first lens, and the phase delay film is used to change the polarization state of light passing through the phase delay film.

[0017] In some embodiments, the lens assembly further includes a second lens and a reflective polarizing film, wherein the second lens includes a first surface and a second surface opposite to each other, and the first surface of the second lens faces the second surface of the first lens. The reflective polarizing film is disposed on the first surface of the second lens, and the reflective polarizing film is used to reflect the linear polarized light in the P polarization state from the phase delay film toward the phase delay film, and to transmit the linear polarized light in the S polarization state from the phase delay film.

[0018] A display module provided in an embodiment of the present application includes the lens assembly and a display screen as described in any of the above embodiments, and the display screen is used to emit light to the lens assembly.

[0019] The electronic device provided in the embodiment of the present application includes a main body and the display module described in the above embodiment, and the display module is combined with the main body.

[0020] The lens assembly, display module and electronic device of the present application utilize a modulating thin film layer and a dielectric thin film layer to coordinately adjust the refractive index of a semi-transparent and semi-reflective film, thereby making the P polarization state and the S polarization state of the circularly polarized light more uniform, so that the circular polarization state of the circularly polarized light passing through the semi-transparent and semi-reflective film is maintained, and the circular polarization degree of the transmitted circularly polarized light is higher, thereby reducing the influence of stray light on the propagation of subsequent light in the optical path, thereby reducing ghost images and improving imaging effects.

[0021] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 is a schematic diagram of the structure of a display module of certain embodiments of the present application;

[0024] Figure 2 yes Figure 1 A schematic diagram showing the relationship between the reflectivity of the lens assembly in the display module and the wavelength of light;

[0025] Figure 3 yes Figure 1 A partial structural schematic diagram of a display module shown;

[0026] Figure 4 yes Figure 3 The enlarged schematic diagram of part IV;

[0027] Figure 5 yes Figure 3 The enlarged schematic diagram of part V;

[0028] Figure 6 is a schematic diagram of the structure of an electronic device according to some embodiments of the present application;

[0029] Figure 7 It is a schematic diagram of the three-dimensional structure of an electronic device according to certain embodiments of the present application.

[0030] Description of main component symbols:

[0031] Lens assembly 10, first lens 12, first surface 120 of the first lens, second surface 122 of the first lens, semi-transmissive and semi-reflective film 14, modulation film layer 140, modulation unit 1401, dielectric 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] Display module 100, display screen 20;

[0033] Electronic device 1000, main body 200. DETAILED DESCRIPTION

[0034] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of the present application, and cannot be understood as limiting the embodiments of the present application.

[0035] The disclosure below provides many different embodiments or examples to realize different structures of the embodiments of the present application. In order to simplify the disclosure of the embodiments of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. The embodiments of the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the embodiments of the present application provide various specific processes and examples of materials, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0036] In a virtual reality device based on the ultra-short-focus optical folded light path (Pancake) optical solution, after the image source enters the beam splitter, the light rays are folded back and forth between the lenses in the lens group for many times, and finally emitted into the human eye.

[0037] In the optical path of the lens group, "useful" light is light that effectively follows the complete folded optical path designed by the lens to form an image, and "harmful" light is light that reaches the human eye without following the complete folded optical path. These "harmful" lights do not participate in imaging, but act as stray light to reduce contrast and act as ghosts to interfere with normal viewing. Among them, the circular deflection of circularly polarized light in the optical path is an important indicator to ensure the proportion of "useful" light. Specifically, the lower the circular deflection of circularly polarized light in the optical path, the lower the proportion of "useful" light. Conversely, the higher the circular deflection 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 circular polarization is maintained on the outgoing side when circular polarization is transmitted once. When the incident light is circularly polarized, the outgoing light may contain circular polarization, elliptically polarized light, or both. When there is less circular polarization and more elliptically polarized light in the outgoing light, the circular polarization is low; when there is more circular polarization and less elliptically polarized light in the outgoing light, the circular polarization is high.

[0039] The Pancake optical solution mainly includes a beam splitter, a phase delay plate and a reflective polarizing film. The light source emits right-handed circularly polarized light (Right Cricular Polarized, RCP). After passing through the beam splitter, 50% of the light is reflected and 50% of the light passes through the beam splitter. The transmitted right-handed circularly polarized light passes through the phase delay plate and becomes P-linearly polarized light. The P-linearly polarized light reaches the reflective polarizing film, and the reflective polarizing film reflects the P-linearly polarized light. After the P-linearly polarized light passes through the phase delay plate for the second time, it turns back to right-handed circularly polarized light. The right-handed circularly polarized light is reflected by the beam splitter and becomes left-handed circularly polarized light (Left Cricular Polarized, LCP). The left-handed circularly polarized light passes through the phase delay plate for the third time and becomes S-linearly polarized light. The S-linearly polarized light reaches the reflective polarizing film and transmits, and finally enters the human eye. In this process, the phase delay plate is used to convert the polarization state of light. In order to ensure that the circularly polarized light passing through the phase delay plate can be converted into linearly polarized light, it is necessary to ensure that the light directed to the phase delay plate is circularly polarized light. When the circularly polarized light passes through the beam splitter, since the distance between the light source and the beam splitter is close and the size of the light source is small, the incident angle of the light incident on the beam splitter is large. In this case, the circularly polarized light passing through the beam splitter will be converted into elliptically polarized light. The elliptically polarized light cannot be converted into linearly polarized light after passing through the phase delay plate, and thus cannot be reflected by the reflective polarizing film, but becomes stray light propagating in the light path. The stray light gathers in the light path between the lenses, generating shadows, which are ultimately manifested as ghost images in the picture seen by the user, and the imaging effect is poor. In order to solve this problem, the present application provides a lens assembly 10( Figure 1 ), the display device 100 ( Figure 6 shown) and electronic equipment ( Figure 7shown).

[0040] See also Figure 1 The lens assembly 10 provided in the embodiment of the present 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 each other, and the semi-transparent and semi-reflective film 14 includes a modulation film layer 140 and a dielectric film layer 142. The modulation film layer 140 is disposed on the first surface 120 of the first lens 12, and the dielectric film layer 142 is disposed on a side of the modulation film layer 140 away from the first lens 12. The dielectric film layer 142 and the modulation film layer 140 are used to cooperate in adjusting the refractive index of the semi-transparent and semi-reflective film 14, so that the circularly polarized light incident on the semi-transparent and semi-reflective film 14 at different incident angles remains as 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, etc.), and mainly utilizes 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 opposite to each other.

[0043] The semi-transmissive and semi-reflective film 14 is used to transmit circularly polarized light incident therein, and can reflect the circularly polarized light from the second surface 122 of the first lens 12 into circularly polarized light with the opposite rotation direction.

[0044] The semi-transparent and semi-reflective film 14 is arranged on the first surface 120 of the first lens 12, and the semi-transparent and semi-reflective film 14 includes a modulation film layer 140 and a dielectric film layer 142. The semi-transparent and semi-reflective film 14 is in the form of a stacked arrangement of the modulation film layer 140 and the dielectric film layer 142, and the refractive index of the modulation film layer 140 and the dielectric film layer 142 can be controlled to be different. By adjusting the refractive index and film thickness of the modulation film layer 140 and the dielectric film layer 142, the light splitting effect of the semi-transparent and semi-reflective film 14 can be changed, that is, the circular deflection of the circularly polarized light after transmission can be improved.

[0045] The above-mentioned lens assembly 10 utilizes the modulation film layer 140 and the dielectric film layer 142 to coordinately adjust the refractive index of the semi-transparent and semi-reflective film 14, so as to make the P polarization state and the S polarization state of the 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 circular polarization state, and the circular deflection of the transmitted circularly polarized light is higher, thereby reducing the influence of stray light on the propagation of subsequent light in the optical path, thereby reducing ghost images and improving imaging effects.

[0046] In some embodiments, the dielectric film layer 142 and the modulation film layer 140 are used to control the difference between the refractive index of the P polarization state and the refractive index of the S polarization state of the circularly polarized light transmitted and reflected by the semi-transparent and semi-reflective film 14, so that the difference in the splitting amount of the P polarization state and the S polarization state of the circularly polarized light entering therein is less than a preset threshold.

[0047] In this way, by controlling the difference between the refractive index of the P polarization state and the refractive index of the S polarization state of the circularly polarized light, the circular polarization degree of the circularly polarized light can be made higher.

[0048] Specifically, the circular deflection of circularly polarized light is related to the difference between the refractive index of the P polarization state and the refractive index of the S polarization state of the circularly polarized light. The dielectric film layer 142 and the modulation film layer 140 can make the difference between the splitting amount of the P polarization state and the S polarization state of the circularly polarized light entering therein smaller than a preset threshold. In an ideal state, if the splitting amount of the P polarization state and the S polarization state are equal, the circular deflection of the circularly polarized light can be optimized. The preset threshold can make the splitting amount of the P polarization state and the S polarization state close to the ideal state, that is, the preset threshold can make the splitting amount of the P polarization state and the S polarization state approximately equal. The preset threshold can be a reasonable range obtained according to experiments or experience, and is not specifically limited here.

[0049] See also Figure 2 , Figure 2 Schematic diagram of the relationship between the reflectivity of circularly polarized light on the semi-transparent and semi-reflective film 14 and the wavelength of the light. In the semi-transparent and semi-reflective film 14, the difference between the refractive index of the P polarization state and the refractive index of the S polarization state of the circularly polarized light is adjusted to make the splitting amount of the P polarization state and the S polarization state more uniform. The preset threshold is Figure 2 The above reaction is the reflectivity R S and R P The smaller the distance is, the higher the circular polarization degree of the circularly polarized light after passing through the semi-transparent and semi-reflective film 14 is.

[0050] Specifically, see Figure 1 and Figure 3 In some embodiments, the modulation film layer 140 includes a plurality of columnar modulation units 1401 , and the plurality of modulation units 1401 are arranged side by side on the first surface 120 of the first lens 12 , and the long 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 inclination angle of the long axis of each modulation unit 1401 relative to the optical axis O of the first lens 12, and cooperates with the dielectric film layer 142 to maintain the polarization state of the transmitted part of the incident light.

[0052] Specifically, Figure 1 As shown, the optical axis of the first lens 12 is marked as O, the major axis of the modulation unit 1401 is marked as C, and the major axis C of the modulation unit 1401 is inclined relative to the optical axis O, thereby being able to change the refractive index of the modulation film layer 140 so that it forms a refractive angle difference with the refractive index of the dielectric film layer 142, so that the circularly polarized light incident on the semi-transparent and semi-reflective film 14 at different incident angles remains as 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, and there is an angle between the normal of the incident point on the first surface 120 of the first lens 12 and the major axis of the modulation unit 1401, and the angle is related to the curvature radius 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 the light source that can emit circularly polarized light in a direction perpendicular to the optical axis O of the first lens 12.

[0054] Thus, in the lens assembly 10, as shown in FIG. Figure 3 As shown, a tangent line is drawn along the mirror direction of the first lens 12, and the positional relationship between the lens assembly 10 and the light source is equivalent to a geometric relationship on a plane. 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 by the 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 the light source that can emit circularly polarized light in a direction perpendicular to the optical axis O of the first lens 12.

[0055] Specifically, 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 line of the first surface 120 of the first lens 12 through the incident point A is denoted as H, the normal line of 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 the circularly polarized light that can be emitted by the light source in the direction perpendicular to the optical axis O of the first lens 12 is L2, the perpendicular line of the optical axis O through the incident point A is denoted as D, indicating the axial 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 light is ∠α, the angle between the major axis C of the modulation unit 1401 and the normal line 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. Depending on the position of the incident point A on the first surface 120 of the first lens 12, the value of ∠α may also vary, such as Figure 4 and Figure 5 When the incident circularly polarized light is incident in the direction of the optical axis O close to the first lens 12, even if the modulating film layer 140 and the dielectric film layer 142 have the same refractive index, the circular deflection of the circularly polarized light passing through the semi-transparent and semi-reflective film 14 will be higher. 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] ∠α' is equal to the reflection angle of the incident light, so ∠α=∠α', ∠β is the complementary angle of ∠α, so ∠β=90°-∠α.

[0057] According to the above relationship, geometric calculation is performed:

[0058]

[0059]

[0060]

[0061] Through the above geometric derivation, it can be known that 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 that can be emitted by the light source in a 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 curvature radius R of the first lens 12 can be obtained, and the angle ∠α' between the major axis C of the modulation unit 1401 and the normal V of the first surface can be obtained. According to ∠α', the first lens 12 is coated to obtain a modulation thin film layer 140 having 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, so as to cooperate with the dielectric thin film layer 142 to adjust the light splitting effect of the semi-transparent and semi-reflective film 14.

[0062] In some embodiments, the angle ranges from [5°, 80°].

[0063] Thus, within this range, the size of the lens assembly 10 can be made smaller while maintaining a better effect of the semi-transparent and semi-reflective film 14 .

[0064] Specifically, the lens assembly 10 is used in the display device 1000 ( Figure 6 or Figure 7In the case of (as shown), according to the size requirements of the lens assembly 10, there are certain restrictions on the relevant dimensions of the lens assembly 10. Therefore, according to the above method for calculating the angle and the comprehensive consideration of the size requirements of the lens assembly 10, the value range of the angle is [5°, 80°], and the value of the angle gradually increases from the direction close to the optical axis O to the direction away from the optical axis O. In this way, the lens assembly 10 can be smaller in size and have a good imaging effect. When the angle ∠α' is less than 5° or when the angle ∠α' is greater than 80°, it may cause the imaging effect of the lens assembly 10 to meet the requirements but the size of the lens assembly 10 is larger, or the size of the lens assembly 10 is smaller but the imaging effect of the lens assembly 10 is worse. Therefore, the value range of the angle is [5°, 80°]. For example, the value of the angle can be 5°, 10°, 20°, 30°, 40°, 45°, 50°, 60°, 70° or 80°, or any other value in the range [5°, 80°].

[0065] In some embodiments, the thickness of the dielectric film layer 142 is in the range of [20 nm, 2000 nm].

[0066] In some embodiments, the thickness of the modulation thin film layer 140 is in the range of [20 nm, 2000 nm].

[0067] In this way, by selecting the thickness of the dielectric film layer 142 and the modulation film layer 140 within the value range, the characteristics of the semi-transmissive and semi-reflective film 14 can be ensured and the overall size of the lens assembly 10 can be controlled.

[0068] Specifically, the dielectric film layer 142 and the modulation film layer 140 affect their reflectivity through their material properties and the thickness of the film, thereby affecting the performance of the semi-transparent and semi-reflective film 14. When the incident circularly polarized light is incident on the film surface, there is a refraction angle difference between the dielectric film layer 142 and the modulation film layer 140. By controlling the refraction angle difference, the spectroscopic characteristics of the P polarization state and the S polarization state of the circularly polarized light can be controlled, making the spectroscopic characteristics of the P polarization state and the S polarization state of the circularly polarized light more uniform.

[0069] The thickness of the modulation film layer 140 ranges from [20nm, 2000nm]. For example, the thickness of the modulation film layer 140 can be 20nm, 50nm, 100nm, 300nm, 500nm, 1000nm, 1200nm, 1500nm, 1800nm ​​or 2000nm, or any other value in the range [20nm, 2000nm]. If the thickness of the modulation film layer 140 is less than 20nm, the processing difficulty is high, and the modulation unit 1401 of the modulation film layer 140 may not be formed, or the refractive index of the modulation film layer 140 may be affected due to the small thickness. If the thickness of the modulation film layer 140 is greater than 2000nm, the refractive index of the modulation film layer 140 and the overall thickness of the first lens 12 may be affected.

[0070] The thickness of the dielectric film layer 142 is in the range of [20nm, 2000nm]. For example, the thickness of the dielectric film layer 142 can be 20nm, 50nm, 100nm, 300nm, 500nm, 1000nm, 1200nm, 1500nm, 1800nm ​​or 2000nm, or any other value in the range of [20nm, 2000nm]. If the thickness of the dielectric film layer 142 is less than 20nm, the processing difficulty is high, and the modulation unit 1401 of the modulation film layer 140 may not be formed, or the refractive index of the dielectric film layer 142 may be affected due to the too small thickness; if the thickness of the dielectric film layer 142 is greater than 2000nm, the refractive index of the dielectric film layer 142 and the overall thickness of the first lens 12 may be affected.

[0071] In some embodiments, the material of the dielectric film layer 142 is oxide.

[0072] In some embodiments, the material of the modulation thin film layer 140 is oxide or metal.

[0073] In this way, a semi-transmissive and semi-reflective effect on incident light is achieved through the material properties of the dielectric film layer 142 and the modulation film layer 140 .

[0074] Specifically, the semi-transparent and semi-reflective film 14 is usually disposed on the first surface 120 of the first lens 12 by a coating process. Among the coating materials, oxides or metal materials that can realize the functions of the semi-transparent and semi-reflective film 14 are selected as the materials of the dielectric film layer 142 and the modulation film layer 140 according to the refractive index of the coating material, the requirements of the processing technology on the material, etc.

[0075] The material of the dielectric film layer 142 is oxide, and the material of the modulation film layer 140 can be oxide or metal. When the materials of the dielectric film layer 142 and the modulation film layer 140 are both oxides, after processing, the dielectric film layer 142 and the modulation film layer 140 formed by the oxide material can be more closely combined with the first lens 12 and are not easy to fall off. The oxide can be any one 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 modulation thin film layer 140 may be made of a metal material, and the metal material may be any one 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 is in the range of [50 nm, 2000 nm].

[0078] In this way, the modulation film layer 140 is made of a metal material, which cooperates with the oxide material of the dielectric film layer 142 to adjust the difference in refractive index, so as to better control the light splitting effect of the semi-transparent and semi-reflective film 14 .

[0079] Specifically, the material of the modulation film layer 140 can be selected from metal materials. The refractive index difference between metal materials and oxide materials is greater. The selection of metal materials for the material of the modulation film layer 140 can better cooperate with the oxide material of the dielectric film layer 142 to adjust the refractive index difference between the two. The thickness of the modulation film layer 140 ranges from [50nm, 2000nm]. For example, the thickness of the modulation film layer 140 can be 50nm, 100nm, 150nm, 300nm, 500nm, 1000nm, 1200nm, 1500nm, 1800nm ​​or 2000nm, or any other value in the range [50nm, 2000nm]. If the thickness of the modulation film layer 140 is less than 50nm, the processing difficulty is high, and the modulation film layer 140 may not be formed. If the thickness of the modulation film layer 140 is greater than 2000nm, it may affect the refractive index of the modulation 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 , which 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 passing through the phase retardation layer 16 .

[0081] In this way, the light passing through 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 two polarization components of polarized light with mutually perpendicular vibration directions, thereby changing the polarization characteristics of the light.

[0083] The 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 light path, for example, it can convert linearly polarized light into circularly polarized light, or convert circularly polarized light into linearly polarized light.

[0084] exist Figure 1 In the embodiment shown, 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 a side close to 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 opposite to 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 arranged on the first surface 180 of the second lens 18. The reflective polarizing film 19 is used to reflect the linear polarized light of the P polarization state from the phase retardation layer 16 toward the phase retardation layer 16, and to transmit the linear polarized light of the S polarization state from the phase retardation layer 16.

[0087] In this way, the second lens 18 can reflect the P linear polarized light and transmit the S linear polarized light, and finally emit the S linear polarized light.

[0088] Specifically, the second lens 18 is an optical element made of a light-transmitting material (such as glass, plastic or crystal, etc.), and mainly utilizes the refraction of light to refract light in the optical path of the lens assembly 10 .

[0089] The reflective polarizing film 19 can selectively transmit light. The reflective polarizing film 19 has a transmission axis, and light with a polarization direction parallel to the transmission axis can pass through the reflective polarizing film 19, and light with a polarization direction perpendicular to the transmission axis can be reflected by the reflective polarizing film 19. In one embodiment, the reflective polarizing film 19 is used to transmit S-polarized light and reflect P-polarized light, and the polarization direction of the P-polarized light is perpendicular to the polarization direction of the S-polarized light. In other words, 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 direction 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 opposite to 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 arranged on the first surface 180 of the second lens 18. The reflective polarizing film 19 is used to reflect the P linear polarized light from the phase delay layer 16 toward the phase delay layer 16, and pass through the phase delay layer 16 to change it back into right-handed circularly polarized light. The right-handed circularly polarized light is reflected by the beam splitter and becomes left-handed circularly polarized light. The left-handed circularly polarized light passes through the phase delay layer 16 for the third time and becomes S linear polarized light. Finally, the reflective polarizing film 19 transmits the S linear polarized light from the phase delay layer 16.

[0091] To summarize, 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 opposite to each other, the second lens 18 includes a first surface 180 and a second surface 182 opposite to each other, the second lens 18 is arranged on the side where the second surface 122 of the first lens 12 is located, a semi-transparent and semi-reflective film 14 is arranged on the first surface 120 of the first lens 12, a phase retardation layer 16 is arranged on the second surface 122 of the first lens 12, and a reflective polarizing film 19 is arranged on the second surface 182 of the second lens 18. The light source emits circularly polarized light. According to the different incident angles of the circularly polarized light directed to 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 characteristics of the P polarization state and the S polarization state of the circularly polarized light passing through the semi-transparent and semi-reflective film 14 can be controlled, so that the spectral separation of the P polarization state and the S polarization state of the circularly polarized light is more uniform, thereby ensuring the circular deflection of the circularly polarized light passing through the semi-transparent and semi-reflective film 14 from different angles, reducing the generation of elliptically polarized light, and then reducing the generation of stray light in the subsequent optical path, thereby improving the imaging effect.

[0092] The display module 100 provided in the embodiment of the present application includes the lens assembly 10 of any one of the above embodiments and a display screen 20 , and the display screen 20 is used to emit light to the lens assembly 10 .

[0093] Specifically, the display screen 20 is used as a light source to emit light to the lens assembly 10. The display screen 20 can be an organic light emitting diode (OLED) display panel, a silicon-based OLED display panel, a micro organic light emitting diode (MicroOLED) display panel, a micro light emitting diode (Mini LED) display panel, a liquid crystal display panel, a silicon-based liquid crystal display panel, etc.

[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 , and the quarter-wave plate can convert the linearly polarized light emitted by the display screen 20 into circularly polarized light.

[0095] In other embodiments, the display screen 20 is configured to emit circularly polarized light, so that there is no need to provide a quarter-wave plate in front of the display screen 20 , which is beneficial for streamlining the structure of the display module 100 and reducing its size.

[0096] See also Figure 6 and Figure 7 The electronic device 1000 provided in the embodiment of the present application includes a main body 200 and the display module 100 of the above embodiment, and the display module 100 is combined with the main body 200.

[0097] The lens assembly 10, display module 100 and electronic device 1000 of the present application utilize a modulating thin film layer 140 and a dielectric thin film layer 142 to cooperate in adjusting the refractive index of the semi-transparent and semi-reflective film 14, thereby making the P polarization state and the S polarization state of the circularly polarized light more uniform, so that the circular polarization state of the circularly polarized light passing through the semi-transparent and semi-reflective film 14 is maintained, and the circular polarization degree of the transmitted circularly polarized light is higher, thereby reducing the influence of stray light on the propagation of subsequent light in the optical path, thereby reducing ghost images and improving the imaging effect.

[0098] Specifically, the electronic device 1000 may be a wearable electronic device, including but not limited to a head-mounted display, smart glasses, a smart watch or a bracelet, and the like.

[0099] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0100] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above implementation methods within the scope of the present application.

Claims

1. A lens assembly, characterized in that: include: A first lens, the first lens comprising a first surface and a second surface opposite to each other; and A semi-transparent and semi-reflective film is arranged 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 arranged on the first surface of the first lens, and the dielectric film layer is arranged on a side of the modulation film layer away from the first lens, and 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 as circularly polarized light after entering the first lens.

2. The lens assembly according to claim 1, characterized in that The dielectric film layer and the modulation film layer are used to control the difference between the refractive index of the P polarization state and the refractive index of the S polarization state of the circularly polarized light transmitted and reflected by the semi-transparent and semi-reflective membrane, so that the difference in the splitting amount of the P polarization state and the S polarization state of the circularly polarized light entering therein is less than a preset threshold.

3. The lens assembly according to claim 1, characterized in that The modulation film layer includes a plurality of columnar modulation units, and the plurality of modulation units are arranged side by side on the first surface of the first lens. The long axis of each modulation unit is inclined compared to the optical axis of the first lens.

4. The lens assembly according to claim 3, characterized in that The intersection of the major axis of the modulation unit and the first surface of the first lens is used as the incident point, and there is an angle between the normal of the incident point on the first surface of the first lens and the major axis of the modulation unit, and the angle is related to the curvature radius 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 can be emitted by the light source in a direction perpendicular to the optical axis of the first lens.

5. The lens assembly according to claim 4, characterized in that: The value range of the angle is [5°, 80°].

6. The lens assembly according to any one of claims 1 to 5, characterized in that: The thickness of the dielectric thin film layer ranges from [20 nm to 2000 nm]; and / or, The thickness of the modulation thin film layer ranges from [20nm to 2000nm].

7. The lens assembly according to any one of claims 1 to 5, characterized in that: The material of the dielectric film layer is oxide; and / or, The material of the modulation thin film layer is oxide or metal.

8. The lens assembly according to any one of claims 1 to 5, characterized in that: The material of the modulation thin film layer is metal, and the thickness of the modulation thin film layer ranges from [50nm to 2000nm].

9. The lens assembly according to any one of claims 1 to 5, characterized in that: The lens assembly further includes a phase delay film, which is disposed on the second surface of the first lens and is used to change the polarization state of light passing through the phase delay film.

10. The lens assembly according to claim 9, characterized in that The lens assembly further comprises: a second lens, the second lens comprising a first surface and a second surface opposite to each other, the first surface of the second lens facing the second surface of the first lens; and A reflective polarizing film is disposed on the first surface of the second lens, and is used for reflecting the linearly polarized light in the P polarization state from the phase delay film toward the phase delay film, and transmitting the linearly polarized light in the S polarization state from the phase delay film.

11. A display module, characterized in that: include: The lens assembly according to any one of claims 1 to 10; and A display screen is used to emit light to the lens assembly.

12. An electronic device, characterized in that: include: ontology; and The display module as claimed in claim 11, wherein the display module is combined with the body.

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