Optical module and optical system

Abstract

The application provides an optical module and an optical system, which are applied to the field of near-eye display devices. When a first direction circularly polarized light is emitted into the optical module from a first polarization component, a first polarization conversion component converts the light into a second direction circularly polarized light and transmits the light to a second polarization conversion component through a first lens. Then, the light is reflected back to the first polarization conversion component, and is reflected as the first direction circularly polarized light and transmitted out through the second polarization conversion component. When the first direction circularly polarized light is emitted into the optical module from the second polarization conversion component, the second polarization conversion component transmits the first direction circularly polarized light to the first polarization conversion component. Then, the light is reflected as the second direction circularly polarized light and transmitted to the second polarization conversion component. Then, the light is reflected back to the first polarization conversion component, and is converted into the first direction circularly polarized light and transmitted out. In the scheme, the front surface of the optical module does not have to face the display component during assembly of the optical module, so that the flexibility of the assembly device is improved.

Description

Technical Field

[0001] This invention relates to the field of near eye display (NED) device technology, and more particularly to an optical module and optical system. Background Technology

[0002] Near-eye displays are the most typical medium in the metaverse, and their development has accelerated in recent years due to breakthroughs in hardware and software solutions. To further reduce the size and weight of these devices while maintaining excellent optical performance, current near-eye displays are gradually replacing traditional Fresnel imaging with ultra-short-throw optical pancake designs. The pancake design utilizes the conversion of polarized light to fold the optical path, thereby reducing the size and weight of the device, making it more compact and lightweight.

[0003] However, due to their structural characteristics, the optical modules based on the Pancake scheme have a front and a back. Therefore, when assembling the device, it is necessary to distinguish the front and back of the optical modules and install them correctly. This results in high accuracy requirements and poor flexibility in assembling near-eye display devices.

[0004] Therefore, there is an urgent need for an optical module and optical system to improve the flexibility of assembling near-eye display devices. Summary of the Invention

[0005] This invention provides an optical module and optical system to improve the flexibility of assembling near-eye display devices.

[0006] In a first aspect, embodiments of the present invention provide an optical module, the optical module comprising, in sequence, a first polarization conversion component, a first lens, and a second polarization conversion component; when circularly polarized light in a first direction enters the optical module from the first polarization component: the first polarization conversion component is used to convert the circularly polarized light in the first direction into circularly polarized light in a second direction and transmit it through the first lens to the second polarization conversion component; the second polarization conversion component is used to reflect the circularly polarized light in the second direction back to the first lens and transmit it to the first polarization conversion component; the first polarization conversion component is further used to reflect the circularly polarized light in the second direction back into circularly polarized light in the first direction, and transmit the circularly polarized light in the first direction through the first lens to the second polarization conversion component. The second polarization conversion component is also used to emit circularly polarized light in the first direction; when the circularly polarized light in the first direction enters the optical module from the second polarization conversion component: the second polarization conversion component is used to transmit the circularly polarized light in the first direction to the first lens and reach the first polarization conversion component; the first polarization conversion component is used to reflect the circularly polarized light in the first direction into circularly polarized light in the second direction and emit the circularly polarized light in the second direction through the first lens to the second polarization conversion component; the second polarization conversion component is also used to reflect the circularly polarized light in the second direction back to the first lens and emit it towards the first polarization conversion component; the first polarization conversion component is also used to convert the circularly polarized light in the second direction into circularly polarized light in the first direction and emit it.

[0007] In the above scheme, if the side of the optical module closest to the first polarization conversion component is called the front side of the optical module, and the side of the optical module closest to the second polarization conversion component is called the back side of the optical module, it is possible to achieve optical path folding regardless of whether the light enters from the front or the back side of the optical module. Therefore, when assembling the optical module into the optical system, it is no longer necessary to have the front side of the optical module facing the display component. On the contrary, it is possible to have the front side or the back side of the optical module facing the display component, thereby improving the flexibility of assembling near-eye display devices.

[0008] Optionally, the first polarization conversion component includes a semi-transparent and semi-reflective film and N light conversion components; where N is a positive integer; the semi-transparent and semi-reflective film is disposed on the side close to the first lens, and the light conversion components are disposed on the side away from the first lens; the first surface of the light conversion component refers to the side facing the semi-transparent and semi-reflective film, and the second surface of the light conversion component refers to the side facing away from the semi-transparent and semi-reflective film; when light is incident on the light conversion component from the first surface, the light conversion component is used to absorb circularly polarized light in the first direction and transmit circularly polarized light in the second direction; when light is incident on the light conversion component from the second surface, the light conversion component is used to transmit circularly polarized light in the first direction and absorb circularly polarized light in the second direction.

[0009] In the above solution, a semi-transparent and semi-reflective film is used to transmit and reflect light, allowing the light to be folded. This reduces the size and weight of the optical module, making the optical device more compact and lightweight. Furthermore, the light conversion component allows for light path folding regardless of whether the light enters from the front or back of the optical module. Additionally, the light conversion component can absorb stray light and reduce ghosting, effectively improving the imaging clarity of the optical module.

[0010] Optionally, the optical conversion component includes a first phase retarder, a first polarizer, and a second phase retarder in sequence from the first surface to the second surface; wherein the optical axis direction of the first phase retarder is the same as that of the second phase retarder.

[0011] The above solution ensures that light can achieve the desired effect regardless of whether it enters the optical module from the front or back, or from the first or second surface of the light conversion component, thus folding the optical path of the optical module. Furthermore, in existing technologies, display components incorporate quarter-wave plates to convert the natural light emitted by the display component into circularly polarized light. Similarly, optical modules also require quarter-wave plates to convert between circularly and linearly polarized light. However, the type of quarter-wave plate in the display component may differ from that in the optical module, and different types of quarter-wave plates have varying conversion efficiencies. Therefore, if the type of quarter-wave plate in the display component and the optical module does not match, a conversion mismatch will occur in the optical path, resulting in stray light and ghosting in the optical module. In this solution, by setting a first phase delayer and a second phase delayer in the light conversion component, when the light emitted by the display component enters the optical module from the light conversion component of the first polarization component, the first phase delayer and the second phase delayer can convert the light conversion efficiency into the light conversion efficiency in the optical module, reduce or avoid the problem of conversion mismatch in the optical path, thereby reducing stray light and ghosting in the optical module and further improving the clarity of the optical module.

[0012] Optionally, the optical conversion assembly further includes a second polarizer located between the first polarizer and the second phase delayer; the direction of the transmission axis of the second polarizer is the same as the direction of the transmission axis of the first polarizer.

[0013] In the above scheme, by setting a second polarizer, stray light in the optical path can be further absorbed, thereby improving the clarity of the optical module.

[0014] Optionally, from the direction away from the first lens to the direction closer to the first lens, the second polarization conversion component sequentially includes a third phase retarder, a third polarizer, a polarizing reflective film, and a fourth phase retarder; the optical axis of the third phase retarder and the optical axis of the fourth phase retarder are at a 90° angle; the optical axis of the first phase retarder and the optical axis of the fourth phase retarder are the same, or the optical axis of the first phase retarder and the optical axis of the third phase retarder are the same; the transmission axis of the third polarizer is the same as the transmission axis of the polarizing reflective film; the transmission axis of the first polarizer and the transmission axis of the third polarizer are orthogonal, or the transmission axis of the first polarizer and the transmission axis of the third polarizer are the same.

[0015] In existing technologies, if light enters the optical module from the reverse side, i.e., from the polarizing reflective film end, optical path folding cannot be achieved, and the optical module cannot form an image. However, this solution allows light to enter the optical module from the reverse side, i.e., from the second polarization conversion component end, achieving optical path folding. This eliminates the need to distinguish between the front and back sides of the optical module when assembling it into the optical system, improving the flexibility of assembling near-eye display devices. Furthermore, this solution incorporates a third phase delay unit. When light emitted from the display component enters the optical module from the second polarization component, the third phase delay unit converts the light conversion efficiency to the conversion efficiency within the optical module, reducing or eliminating conversion mismatch in the optical path. This mitigates stray light and ghosting in the optical module, further improving its clarity.

[0016] Optionally, the radii of curvature of the two surfaces of the first lens are of the same size but opposite signs.

[0017] With the above configuration, the first lens is axially symmetrical with its central axis as the center line. Therefore, when assembling the optical module into the optical system, the imaging effect is consistent regardless of whether the optical module is assembled from the front or the back, thus further improving the assembly accuracy of the optical module.

[0018] Optionally, any phase delayer can be a quarter-wave plate, two eighth-wave plates, or four sixteenth-wave plates.

[0019] The above solutions offer a wide range of phase delayer types to suit various business scenarios and assembly requirements.

[0020] Optionally, the optical module also includes M second lenses, where M is an even number, and the M second lenses are located on both sides of the first polarization conversion component and the second polarization conversion component, respectively; the M second lenses are arranged symmetrically with the central axis of the first lens as the center line.

[0021] In the above scheme, the addition of a second lens facilitates further adjustment of the optical imaging effect. Furthermore, since the M second lenses are axially symmetrically arranged, the imaging effect is consistent regardless of whether the optical module is assembled from the front or the back of the optical module when it is assembled into the optical system, thus further improving the assembly accuracy of the optical module.

[0022] In a second aspect, embodiments of the present invention provide an optical system including a display assembly and an optical module of any one of the first aspects; the display assembly is disposed on a side close to a first polarization conversion assembly, or the display assembly is disposed on a side close to a second polarization conversion assembly; the display assembly is used to emit circularly polarized light in a first direction.

[0023] Optionally, the optical system also includes multiple refractive lenses, which are located on both sides of the optical module; the multiple refractive lenses are arranged symmetrically with the central axis of the first lens as the center line.

[0024] In the above scheme, setting multiple refractive lenses is beneficial for further adjusting the optical imaging effect. In addition, since the multiple refractive lenses are axially symmetrically arranged, the imaging effect is consistent whether the optical module is assembled with the front or the back of the optical module, thus further improving the assembly accuracy of the optical module. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in this invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram of a conventional optical system based on the Pancake scheme provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the optical path of a conventional optical system provided in an embodiment of the present invention;

[0028] Figure 3a This is a schematic diagram of the structure of an optical module provided in an embodiment of the present invention;

[0029] Figure 3b A schematic diagram of the central axis of a first lens provided in an embodiment of the present invention;

[0030] Figure 4a A schematic diagram of the optical path of an optical module provided in an embodiment of the present invention;

[0031] Figure 4b This is a schematic diagram of the optical path of another optical module provided in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of a first polarization conversion component provided in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure of an optical conversion component provided in an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the structure of a second polarization conversion component provided in an embodiment of the present invention;

[0035] Figure 8This is a schematic diagram of a possible optical module provided in an embodiment of the present invention;

[0036] Figure 9a A schematic diagram of the structure of an optical system provided in an embodiment of the present invention;

[0037] Figure 9b A schematic diagram of another optical system provided in an embodiment of the present invention;

[0038] Figure 10 This is a schematic diagram of the optical path of an optical system provided in an embodiment of the present invention;

[0039] Figure 11 This is a schematic diagram of the optical path of another optical system provided in an embodiment of the present invention;

[0040] Figure 12 A schematic diagram of the structure of an optical system provided in an embodiment of the present invention;

[0041] Figure 13 This is a schematic diagram of the optical path of an optical system provided in an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0043] It should be noted that in the description of this invention, "multiple" is understood as "at least two". "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A connected to B can represent: A and B directly connected, or A and B connected through C. Furthermore, in the description of this invention, terms such as "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or order.

[0044] The following explanations cover some of the terms used in this invention. It should be noted that these explanations are for the convenience of those skilled in the art and are not intended to limit the scope of protection claimed by this invention.

[0045] I. Semi-permeable and semi-reflective membrane

[0046] A semi-reflective film is a thin film material that combines transparency and reflection, typically composed of multiple optical films. It can reflect some light while maintaining a certain level of transmittance.

[0047] II. Polarizing Reflective Film

[0048] A polarizing reflective film is a thin film material with both polarization and reflection functions, selectively reflecting or transmitting light with a specific polarization direction. By applying a polarizing reflective film, light that does not belong to a specific polarization direction can be reflected. For example, a polarizing reflective film can transmit P-polarized light and reflect S-polarized light, or vice versa. Here, with the plane formed by the incident ray and the normal to the incident interface as a reference, P-polarized light refers to parallel polarized light, whose vibration direction is parallel to this reference plane; S-polarized light refers to perpendicular polarized light, whose vibration direction is perpendicular to this reference plane.

[0049] III. Wave Plate

[0050] A wave plate is a thin film material with special optical properties that can change the polarization state of light, such as converting linearly polarized light into circularly polarized light, or vice versa. Common wave plates include quarter-wave plates and half-wave plates.

[0051] IV. Polarizer

[0052] A polarizer is an optical element used to change the polarization state of light. Polarization refers to the orientation of the vibration direction in a light wave. Ordinary natural light is unpolarized light, in which the vibration direction of the light wave is randomly distributed. Polarized light, on the other hand, has a definite directional vibration direction. The main function of a polarizer is to convert unpolarized or partially polarized light into polarized light with a specific polarization direction. Common polarizers include polarizing filters and polarizing prisms. By using a polarizer, light rays that do not belong to a specific polarization direction can be absorbed. For example, a polarizer can transmit P-polarized light and absorb S-polarized light, or vice versa.

[0053] The preceding text introduced some terms used in the embodiments of the present invention. The following text describes the optical module based on the Pancake scheme in the prior art.

[0054] like Figure 1The diagram shown is a schematic representation of a conventional optical system based on a pancake scheme according to an embodiment of the present invention. This conventional optical system includes a display assembly and an optical module. The optical module includes lens a, a semi-transparent and semi-reflective coating, lens b, a quarter-wave plate, and a polarizing reflective coating. The semi-transparent and semi-reflective coating is located on the surface of lens a facing the display assembly, the quarter-wave plate is located on the surface of lens b facing away from the display assembly, and the polarizing reflective coating is disposed on the quarter-wave plate.

[0055] based on Figure 1 In the optical system, assuming the display component emits right-handed circularly polarized light, and the polarizing reflective film transmits P-polarized light and reflects S-polarized light, the following will combine... Figure 2 The imaging principle of this optical system will be introduced. Figure 2 This is a schematic diagram of the optical path of a conventional optical system provided in an embodiment of the present invention. It should be noted that since lenses a and b can directly transmit light without involving folding or changing the direction of the light rays, this is done to briefly explain the imaging principle. Figure 2 Lens a and lens b are not shown in the diagram. Readers should understand that lens a is actually positioned on the side of the semi-transparent, semi-reflective film facing away from the display assembly, and lens b is actually positioned on the side of the quarter-wave plate facing the display assembly. The imaging principle of existing optical systems is as follows:

[0056] The display assembly emits a cluster of right-handed circularly polarized rays. This cluster of rays first passes through a semi-transparent and semi-reflective film. Because the semi-transparent and semi-reflective film can reflect some light while maintaining a certain transmittance, a portion of the right-handed circularly polarized rays pass through the semi-transparent and semi-reflective film. Figure 2In process 1), the light is incident on a quarter-wave plate. Another portion of the right-hand circularly polarized light passes through the semi-transparent and semi-reflective film and is incident on the display assembly (process 8), causing stray light. For the right-hand circularly polarized light that passes through the semi-transparent and semi-reflective film, the quarter-wave plate converts this portion of the right-hand circularly polarized light into S-linearly polarized light and incident it on the polarizing reflective film (process 2). Because the polarizing reflective film transmits P-polarized light and reflects S-polarized light, the S-polarized light beam, upon reaching the polarizing reflective film, is reflected back to the quarter-wave plate (process 3) and reconverted into right-hand circularly polarized light by the quarter-wave plate (process 4). Next, the right-hand circularly polarized light beam strikes the semi-transparent and semi-reflective film, which then reflects a portion of the right-hand circularly polarized light beam into left-hand circularly polarized light (process 5). This left-hand circularly polarized light beam passes through the quarter-wave plate again, which converts it into P-polarized light (process 6). Finally, the P-polarized light beam strikes the polarizing reflective film. Because the polarizing reflective film transmits P-polarized light and reflects S-polarized light, the P-polarized light beam directly penetrates the polarizing reflective film (process 7). It should be noted that in process 4 above, after the right-hand circularly polarized light is incident on the semi-transparent and semi-reflective film, part of the light is reflected as left-hand circularly polarized light (process 5) and incident on the quarter-wave plate, while another part of the light passes through the semi-transparent and semi-reflective film (process 9) and incident on the display assembly, causing stray light.

[0057] As can be seen from the above process, the light emitted by the display component achieves optical path folding after reflection within the optical system. However, to achieve optical path folding, in existing optical systems, the light emitted by the display component must first pass through a semi-transparent, semi-reflective film in the optical module, and then sequentially through a quarter-wave plate and a polarizing reflective film. Therefore, for the optical module, the side closest to the semi-transparent, semi-reflective film is called the front side, and the side closest to the polarizing reflective film is called the back side. During assembly, the front side of the optical module must face the display component. If the back side of the optical module faces the display component during installation, the entire optical system will malfunction. This results in high accuracy requirements for assembling the optical module, poor assembly flexibility, and the need for proprietary fixtures to prevent assembly errors, leading to significant costs associated with assembling the optical module.

[0058] In addition to the aforementioned problem of poor assembly flexibility caused by the need to distinguish between the front and back sides of the optical modules in existing technologies, existing technologies also have the following problems:

[0059] Question 1: Display components require linear polarizers and quarter-wave plates to convert the natural light emitted by the display components into circularly polarized light. The optical module also needs a quarter-wave plate to complete the conversion between circular and linear polarization of the light. The conversion efficiency of a quarter-wave plate is a function of wavelength, meaning dispersion exists, and different manufacturers and models of quarter-wave plates have different conversion efficiencies. Therefore, if the model of the quarter-wave plate in the display component does not match the model of the quarter-wave plate in the optical module, a conversion mismatch will occur in the optical path, resulting in stray light and ghosting in the optical module.

[0060] Question 2: The function of a semi-transparent and semi-reflective film is to reflect half of the light and transmit the other half. Therefore, when light is folded in the optical module, stray light will be generated, such as the one mentioned above. Figure 2 Both processes 8 and 9 will generate stray light, which will appear as a ghosting effect and reduce the imaging clarity of the optical module.

[0061] Question 3: In optical modules, quarter-wave plates and polarizing reflective films are typically bonded together on the lens surface. If a curved surface coating is used, the surface curvature of the lens is limited due to the film material properties and coating process, making it difficult to control production yield. If a flat surface coating is used, the surface curvature of the lens is completely restricted. Such limitations result in a lack of corresponding optimization variables in optical design, thus restricting the image quality design of the entire optical system.

[0062] Based on the above description, the problems of the existing technology based on the Pancake scheme can be summarized as poor design flexibility, high requirements for assembly accuracy, and difficulty in eliminating ghosting stray light, resulting in poor image quality.

[0063] Therefore, embodiments of the present invention provide an optical module and an optical system that enable optical path folding regardless of whether light enters from the front or back of the optical module. Thus, when assembling the optical module into the optical system, it is no longer necessary for the front of the optical module to face the display assembly; instead, either the front or back of the optical module can face the display assembly, thereby improving the flexibility of assembling the optical system. It should be noted that the shape and thickness of the lenses in all the figures shown in the embodiments of the present invention are for illustrative purposes only and do not represent actual conditions; these will not be elaborated upon further thereafter.

[0064] like Figure 3aThe optical module comprises, in sequence, a first polarization conversion component 301, a first lens 302, and a second polarization conversion component 303. The first lens 302 may include one or more lenses, without specific limitation. The first lens 302 is used to transmit light and its type includes, but is not limited to, biconvex lenses, biconcave lenses, and concave-convex lenses, etc., and its lens surface may be a free-form surface, a spherical surface, or an aspherical surface, etc. The first polarization conversion component 301 and the second polarization conversion component 303 are symmetrically arranged about the central axis of the first lens 302; therefore, the spatial distance between the first polarization conversion component 301 and the first lens 302 is equal to the spatial distance between the second polarization conversion component 303 and the first lens 302.

[0065] Among them, combined Figure 3b Let's introduce the central axis of the first lens. Figure 3b A schematic diagram of the central axis of a first lens provided in an embodiment of the present invention is shown as an example. Wherein, Z is the optical axis direction of the first lens, XY is a planar orthogonal coordinate system perpendicular to the optical axis of the first lens, and Y is the central axis of the first lens.

[0066] Continue as Figure 3a As shown, in one possible implementation, the optical module further includes M second lenses (second lens 304 and second lens 305, respectively), where M is an even number. The second lens 304 is used to transmit light, and its type includes, but is not limited to, biconvex lenses, biconcave lenses, and concave-convex lenses, etc., and its lens surface can be a freeform surface, a spherical surface, or an aspherical surface, etc. The M second lenses 304 are respectively located on both sides of the first polarization conversion component 301 and the second polarization conversion component 303. Furthermore, with the central axis of the first lens 302 as the center line, the M second lenses are arranged axially symmetrically. Those skilled in the art will understand that the surface curvature radii of two mutually axially symmetrical second lenses have the same numerical value and the same sign. For example, in... Figure 3a In the example, the optical module includes two second lenses (second lens 304 and second lens 305). These two second lenses are symmetrical about the central axis of the first lens 302. Therefore, the surface radii of curvature of the second lens 304 and the surface radii of curvature of the second lens 305 have the same value and the same sign.

[0067] In this embodiment of the invention, the provision of a second lens facilitates further adjustment of the optical imaging effect. Furthermore, since the M second lenses are axially symmetrically arranged, the imaging effect is consistent regardless of whether the optical module is assembled from the front or the back of the optical module when it is assembled into the optical system, thus further improving the assembly accuracy of the optical module.

[0068] It should be noted that if the optical module only includes a first polarization conversion component, a first lens, and a second polarization conversion component, then the first polarization conversion component and the second polarization conversion component are respectively disposed on two sides of the first lens. If the optical module includes a first polarization conversion component, a first lens, a second polarization conversion component, and multiple second lenses, the first polarization conversion component and the second polarization conversion component can be disposed on two sides of the first lens, or they can be disposed on the sides of the second lenses on both sides of the center line. Furthermore, since the first polarization conversion component contains different films, some of the films inside the first polarization conversion component can be disposed on the first lens, and other films can be disposed on the second lenses. Similarly, since the second polarization conversion component also contains different films, some of the films inside the second polarization conversion component can be disposed on the first lens, and other films can be disposed on the second lenses. In this embodiment of the invention, the disposal methods include, but are not limited to, film application, coating, etc.

[0069] Preferably, the positions of the first polarization conversion component and the second polarization conversion component are symmetrical about the central axis of the first lens 302.

[0070] The optical path diagram of the optical module is shown below. Figure 4a as well as Figure 4b As shown. It should be noted that in this invention, the surface of the optical module on the side of the first polarization conversion component is referred to as the front side of the optical module, and the surface of the optical module on the side of the second polarization conversion component is referred to as the back side of the optical module. Alternatively, the surface of the optical module on the side of the first polarization conversion component can be referred to as the back side of the optical module, and the surface of the optical module on the side of the second polarization conversion component can be referred to as the front side of the optical module. In this embodiment of the invention, the surface of the optical module on the side of the first polarization conversion component is uniformly referred to as the front side of the optical module for explanation and description.

[0071] like Figure 4aAs shown, circularly polarized light in the first direction enters the optical module from the front. This first-direction circularly polarized light can refer to light emitted from the display component, and can be either right-handed or left-handed circularly polarized; this embodiment of the invention does not specifically limit this. When light enters the optical module from the front, i.e., the first polarization component, as circularly polarized light in the first direction, the first polarization conversion component 301 converts the first-direction circularly polarized light into circularly polarized light in the second direction. If the first-direction circularly polarized light is right-handed, the second-direction circularly polarized light is left-handed; conversely, if the first-direction circularly polarized light is left-handed, the second-direction circularly polarized light is right-handed. This second-direction circularly polarized light passes through the first lens 302 and is directed towards the second polarization conversion component 303. The second polarization conversion component 303 reflects the second-direction circularly polarized light back to the first lens 302 and directs it towards the first polarization conversion component 301. The first polarization conversion component 301 is also used to reflect the circularly polarized light in the second direction into circularly polarized light in the first direction, and then send the beam of circularly polarized light in the first direction through the first lens 302 to the second polarization conversion component 303. The second polarization conversion component 303 is also used to emit the beam of circularly polarized light in the first direction.

[0072] like Figure 4b As shown, circularly polarized light in the first direction enters the optical module from the back of the optical module. The second polarization conversion component 303 transmits the circularly polarized light in the first direction to the first lens 302, and then through the first lens 302 to the first polarization conversion component 301. After that, the first polarization conversion component 301 reflects the circularly polarized light in the first direction into circularly polarized light in the second direction and sends the circularly polarized light in the second direction through the first lens 302 to the second polarization conversion component 303. After that, the second polarization conversion component 303 also reflects the circularly polarized light in the second direction back to the first lens 302 and sends it to the first polarization conversion component 301. The first polarization conversion component 301 also converts the circularly polarized light in the second direction back into circularly polarized light in the first direction and sends it out.

[0073] Through the above Figure 4a as well as Figure 4b It is evident that, if we define the side of the optical module closest to the first polarization conversion component as the front side of the optical module and the side closest to the second polarization conversion component as the back side, light can be folded regardless of whether it enters from the front or back side of the optical module. Therefore, when assembling the optical module into an optical system, it is no longer necessary for the front side of the optical module to face the display component. Instead, either the front or back side of the optical module can face the display component, thereby improving the flexibility of assembling near-eye display devices. Furthermore, the optical module in this embodiment can be provided as a standard product to optical designers, without excessive restrictions on additional lenses added to the optical path, increasing the freedom of overall design and further enhancing the performance of the optical device.

[0074] The structure of the optical module will be described in more detail next.

[0075] In one possible implementation, the radii of curvature of the two surfaces of the first lens 302 are of the same magnitude but opposite signs. This arrangement ensures that the first lens is axially symmetrical about its central axis. Therefore, when assembling the optical module into the optical system, regardless of whether it is assembled from the front or back, the imaging effect is consistent, thus further improving the assembly accuracy of the optical module.

[0076] Furthermore, such as Figure 5 The diagram shown is a structural schematic of a first polarization conversion component provided in an embodiment of the present invention. The first polarization conversion component 301 includes a semi-transparent and semi-reflective film 501 and N optical conversion components 502. Wherein, N is a positive integer. Figure 5 In the example, N is 2, meaning that the first polarization conversion component 301 includes two light conversion components. The transflective film 501 is disposed on the side closer to the first lens 302, and the light conversion component 502 is disposed on the side farther from the first lens. Specifically, the first surface of the light conversion component 502 faces the transflective film, and the second surface of the light conversion component 502 faces away from the transflective film.

[0077] When light rays strike the light conversion component 502 from the first surface, the light conversion component 502 absorbs circularly polarized light in the first direction and transmits circularly polarized light in the second direction. When light rays strike the light conversion component 502 from the second surface, the light conversion component 502 transmits circularly polarized light in the first direction and absorbs circularly polarized light in the second direction.

[0078] For example, assuming the first direction of circularly polarized light is right-handed circularly polarized light and the second direction of circularly polarized light is left-handed circularly polarized light, when a beam of right-handed circularly polarized light is incident on the light conversion component 502 from the first surface, the light conversion component 502 will absorb the beam of right-handed circularly polarized light, so no light will pass through the light conversion component 502; while when a beam of right-handed circularly polarized light is incident on the light conversion component 502 from the second surface, the light conversion component 502 will transmit the beam of right-handed circularly polarized light. Similarly, in this example, when a beam of left-handed circularly polarized light is incident on the light conversion component 502 from the first surface, the light conversion component 502 will transmit the beam of left-handed circularly polarized light; while when a beam of left-handed circularly polarized light is incident on the light conversion component 502 from the second surface, the light conversion component 502 will absorb the beam of left-handed circularly polarized light.

[0079] like Figure 6The diagram shows a schematic representation of an optical conversion component 502 provided in an embodiment of the present invention. From the first surface to the second surface, the optical conversion component 502 sequentially includes a first phase retarder 601, a first polarizer 602, and a second phase retarder 604. The optical axis of the first phase retarder 601 is the same as that of the second phase retarder 604. The transmission axis of the first polarizer 602 forms a 45° angle with the optical axis of the first phase retarder 601. In this embodiment, because the optical axis of the first phase retarder 601 is the same as that of the second phase retarder 604, circularly polarized light incident on the optical conversion component in the first direction can be converted into circularly polarized light in the second direction.

[0080] The above solution ensures that light enters the optical module from either the front or back, i.e., from either the first or second surface of the light conversion component, achieving the desired effect by folding the optical path. Furthermore, as previously mentioned, in the prior art, the model of the quarter-wave plate in the display component does not match the model of the quarter-wave plate in the optical module, leading to conversion mismatch in the optical path and causing stray light and ghosting in the optical module. In this solution, by incorporating a first phase retarder and a second phase retarder in the light conversion component, when light emitted from the display component enters the optical module from the light conversion component of the first polarization component, the first and second phase retarders can convert the light conversion efficiency to the conversion efficiency of the light in the optical module, reducing or avoiding conversion mismatch in the optical path, thereby mitigating stray light and ghosting in the optical module and further improving its clarity.

[0081] In one possible implementation, any phase delayer is a quarter-wave plate, or two eighth-wave plates, or four sixteenth-wave plates.

[0082] Optionally, the optical conversion assembly also includes a second polarizer (such as...). Figure 6 The second polarizer 603 is located between the first polarizer 602 and the second phase retarder 604. The direction of the transmission axis of the second polarizer 603 is the same as that of the transmission axis of the first polarizer 602. The transmission axis of the second polarizer 603 and the optical axis of the second phase retarder 604 are at a 45° angle.

[0083] In this scheme, by setting a second polarizer, stray light in the optical path can be further absorbed, thereby improving the clarity of the optical module.

[0084] like Figure 7The diagram shown is a structural schematic of a second polarization conversion component 303 provided in an embodiment of the present invention. From the direction away from the first lens to the direction closer to the first lens, the second polarization conversion component sequentially includes a third phase retarder 701, a third polarizer 702, a polarizing reflective film 703, and a fourth phase retarder 704.

[0085] In this configuration, the optical axis of the third phase retarder 702 forms a 90° angle with the optical axis of the fourth phase retarder 704. The optical axis of the first phase retarder 601 is the same as that of the fourth phase retarder 704, or the optical axis of the first phase retarder 601 is the same as that of the third phase retarder 701. The transmission axis of the third polarizer 702 forms a 45° angle with the optical axis of the third phase retarder 701. The transmission axis of the third polarizer 702 is the same as the transmission axis of the polarizing reflective film 703; the transmission axis of the first polarizer 602 is orthogonal to the transmission axis of the third polarizer 702, or the transmission axis of the first polarizer 602 is the same as that of the third polarizer 702.

[0086] In existing technologies, if light enters the optical module from the reverse side, i.e., from the end of the polarizing reflective film, optical path folding cannot be achieved, and the optical module cannot form an image. In this embodiment of the invention, by incorporating a third phase retarder, a third polarizer, a polarizing reflective film, and a fourth phase retarder in the second polarization conversion component, optical path folding can be achieved even when light enters the optical module from the reverse side, i.e., from the end of the second polarization conversion component. This eliminates the need to distinguish between the front and back sides of the optical module when assembling it into the optical system, improving the flexibility of assembling near-eye display devices. Furthermore, by incorporating the third phase retarder, when light emitted from the display component enters the optical module from the second polarization component, the third phase retarder can convert the light conversion efficiency to the conversion efficiency of the light within the optical module, reducing or avoiding conversion mismatch in the optical path, thereby mitigating stray light and ghosting in the optical module and further improving its clarity.

[0087] To make the solutions of the embodiments of the present invention clearer, the following describes a specific implementation of an optical module provided by the embodiments of the present invention.

[0088] like Figure 8The diagram shows a possible optical module structure according to an embodiment of the present invention. The optical module includes a first lens 801, a first polarization conversion component 802, a second polarization conversion component 803, and four second lenses (second lens 804, second lens 805, second lens 806, and second lens 807). The radii of curvature of the two surfaces of the first lens 801 are the same in size but opposite in sign. The first polarization conversion component 802 is disposed on the surface of the second lens 804 facing the first lens 801, and the second polarization conversion component 803 is disposed on the surface of the second lens 805 facing the first lens 801. The first polarization conversion component 802 includes a semi-transparent and semi-reflective film and a light conversion component, which sequentially includes a first phase retarder, a first polarizer, a second polarizer, and a second phase retarder. The second polarization conversion component sequentially includes a third phase retarder, a third polarizer, a polarizing reflective film, and a fourth phase retarder. The radii of curvature of the two surfaces of the first lens are the same in size but opposite in sign. The optical axis direction of the first phase retarder is the same as that of the second phase retarder. The transmission axis of the first polarizer is in the same direction as the transmission axis of the second polarizer. The optical axis of the third phase retarder forms a 90° angle with the optical axis of the fourth phase retarder, while the optical axis of the first phase retarder is in the same direction as the fourth phase retarder. The transmission axis of the third polarizer is in the same direction as the transmission axis of the polarizing reflective film. The transmission axis of the first polarizer is in the same direction as the transmission axis of the third polarizer; the polarizing reflective film transmits P-polarized light and reflects S-polarized light, while any polarizer transmits P-polarized light and absorbs S-polarized light.

[0089] In one possible implementation, embodiments of the present invention provide an optical system. Figure 9a as well as Figure 9b A schematic diagram of this optical system is shown. (Refer to...) Figure 9a as well as Figure 9b As shown, the optical system includes not only an optical module but also a display assembly. The display assembly is positioned near the first polarization conversion assembly, or it is positioned near the second polarization conversion assembly. The display assembly is used to emit circularly polarized light in a first direction. The display assembly includes a display. This embodiment of the invention does not specifically limit the type of display; the type of display includes, but is not limited to, LCD-Side View Backlight, LCD-Mini LED Backlight, LCD-Quantum Dot LED Backlight, OLED, Micro-OLED, Micro LED, etc. It should be noted that... Figure 9a as well as Figure 9bIn the examples, the optical module includes a first lens, a first polarization conversion component, and a second polarization conversion component. This is only one possible structure of the optical module and is not a limitation on the solution.

[0090] Based on the above Figure 9a The example optical system assumes that the first polarization conversion component includes a semi-transparent and semi-reflective film, a first phase retarder, a first polarizer, a second polarizer, and a second phase retarder. The first directional circularly polarized light emitted by the display assembly to the optical module is right-handed circularly polarized light. The optical axis of the first phase retarder is the same as that of the second phase retarder. The transmission axis of the first polarizer is the same as that of the second polarizer. The optical axis of the third phase retarder forms a 90° angle with that of the fourth phase retarder, and the optical axis of the first phase retarder is the same as that of the fourth phase retarder. The transmission axis of the third polarizer is the same as that of the polarizing reflective film. The polarizing reflective film transmits P-polarized light and reflects S-polarized light; any polarizer transmits P-polarized light and absorbs S-polarized light. The transmission axis of the first polarizer is the same as that of the third polarizer.

[0091] Table 1 below summarizes the functions of each component in the first polarization conversion assembly and the second polarization conversion assembly.

[0092] Table 1

[0093]

[0094] It should be noted that the embodiments of the present invention are based on the example of a display component emitting right-hand circularly polarized light. If the display component emits left-hand circularly polarized light, the transmission axis direction of the third polarizer and the transmission axis direction of the polarizing reflective film need to be adjusted accordingly.

[0095] The following will combine Figure 10 The imaging principle of this optical system will be introduced. Figure 10 This is a schematic diagram of the optical path of an optical system provided in an embodiment of the present invention. It should be noted that, since the first lens can directly transmit light without altering the direction or shape of the light rays, this diagram is provided for the purpose of briefly explaining the imaging principle. Figure 10 The first lens is not shown in the image; however, the reader should understand that it is actually positioned between the semi-transparent, semi-reflective film and the fourth phase retarder. Its imaging principle is as follows:

[0096] In this process, right-hand circularly polarized light emitted from the display assembly enters the optical module through the second phase retarder. This beam of right-hand circularly polarized light is first converted into P-linearly polarized light by the second phase retarder. Figure 10In process 1), the light beam is directed towards the second polarizer. Since the second polarizer transmits P-polarized light and absorbs S-polarized light, the P-polarized light beam passes through the second polarizer and is directed towards the first polarizer (process 2). Since the first polarizer also transmits P-polarized light and absorbs S-polarized light, the P-polarized light beam passes through the first polarizer and is directed towards the first phase retarder (process 3). Because the optical axes of the first and second phase retarders are the same, and their transmission axes are the same, the P-polarized light beam passing through the two phase retarders is equivalent to passing through a half-wave plate, and its polarization chirality is opposite. Therefore, the first phase retarder converts the P-polarized light beam into left-handed circularly polarized light, which then travels towards the semi-transparent, semi-reflective film (process 4).

[0097] Since the function of a semi-reflective film is to reflect half of the incident light and transmit the other half, left-handed circularly polarized light incident on the film will be split into two paths. The film will reflect some of the light and transmit some. These two paths will be described below:

[0098] For the light reflected by the semi-transparent and semi-reflective film:

[0099] First, the semi-reflective film reflects a portion of the left-handed circularly polarized light, converting it into right-handed circularly polarized light, which is then redirected to the first phase retarder (process 14). Since in the pancake-folded optical path, it is desirable for all light to pass through the semi-reflective film and reach the fourth phase retarder in the second polarization conversion assembly, the right-handed circularly polarized light reflected by the semi-reflective film is also called stray light. This right-handed circularly polarized light is converted into S-polarized light by the first phase retarder and then directed to the first polarizer (process 15). Because the first polarizer transmits P-polarized light and absorbs S-polarized light, this S-polarized light will be absorbed by the first polarizer (process 16). Furthermore, if the first polarizer does not completely absorb the S-polarized light, the second polarizer will further absorb this portion of S-polarized light. In this way, the stray light is extinguished and will not propagate to the display assembly, thus preventing light from reflecting back and forth between the display assembly and the semi-reflective film, thus avoiding stray ghosting.

[0100] For the light passing through the semi-transparent and semi-reflective membrane:

[0101] First, a portion of the left-handed circularly polarized light passes through the semi-transparent and semi-reflective film (process 5). The light passing through the film remains left-handed circularly polarized. Then, this beam of left-handed circularly polarized light strikes the fourth phase retarder. Since the optical axis of the fourth phase retarder is aligned with that of the first phase retarder, the P-lined light after process 3 passes through both the first and fourth phase retarders, effectively passing through a half-wave plate. The polarization direction of the light changes by 2*45° (45° being the angle between the polarizer and the phase retarder), meaning the polarization direction changes by 90°, transforming into S-lined polarized light (process 6), and then strikes the polarizing reflective film. Because the polarizing reflective film transmits the P-lined polarized light but reflects the S-lined polarized light, this beam of S-lined polarized light is reflected by the film and strikes the fourth phase retarder again (process 7). This S-lined polarized light is then converted into left-handed circularly polarized light by the fourth phase retarder and strikes the semi-transparent and semi-reflective film (process 8). It is worth noting that due to the imperfections of the polarizing reflective film, some S-polarized light may pass through the polarizing reflective film, but the third polarizer will absorb this part of the S-polarized light, thereby eliminating stray light and ghosting propagating to the human eye.

[0102] When the left-hand circularly polarized light beam strikes the semi-transparent and semi-reflective film, it is split into two beams. That is, the film reflects some of the light while transmitting some. These two beams will be described separately below.

[0103] For the light passing through the semi-transparent and semi-reflective membrane:

[0104] Left-handed circularly polarized light passes through a semi-transparent, semi-reflective film and is directed towards the first phase retarder (process 17). This beam of left-handed circularly polarized light is converted to P-linearly polarized light after passing through the first phase retarder, and then passes through the first and second polarizers before being directed towards the second phase retarder (process 18). The second phase retarder converts the P-linearly polarized light into right-handed circularly polarized light, which is then directed towards the display assembly (process 19). The display assembly reflects the right-handed circularly polarized light, converting it into left-handed circularly polarized light, which is then directed towards the second phase retarder (process 20). The second phase retarder converts the left-handed circularly polarized light into S-linearly polarized light, which is then directed towards the second polarizer (process 21). The second polarizer absorbs the S-linearly polarized light, eliminating stray light and ghosting propagating towards the human eye (process 22). Furthermore, if the second polarizer does not completely absorb the S-linearly polarized light, the first polarizer will further absorb this portion of the S-linearly polarized light. In this way, stray light will be extinguished.

[0105] For the light reflected by the semi-transparent and semi-reflective film:

[0106] Left-handed circularly polarized light is reflected by a semi-reflective coating, becoming right-handed circularly polarized light, and then directed towards the fourth phase retarder (process 9). This right-handed circularly polarized light is converted into P-linearly polarized light by the fourth phase retarder (process 10), and then passes through a polarizing reflective film (process 11) and a third polarizer (process 12). The third phase retarder converts this P-linearly polarized light back into right-handed circularly polarized light (process 13) and exits the optical module. It is worth noting that due to imperfections in the phase retarder, the P-linearly polarized light converted from the right-handed circularly polarized light after passing through the fourth phase retarder in process 10 may contain some S-linearly polarized light. This S-linearly polarized light may then pass through the polarizing reflective film due to imperfections; however, the third polarizer can re-polarize and filter out this S-linearly polarized light, thereby further eliminating stray light.

[0107] Based on the above Figure 9b The example optical module assumes that its first polarization conversion component includes a semi-transparent and semi-reflective film, a first phase retarder, a first polarizer, a second polarizer, and a second phase retarder. The first directional circularly polarized light emitted by the display assembly to the optical module is right-handed circularly polarized light. The optical axis of the first phase retarder is the same as that of the second phase retarder. The transmission axis of the first polarizer is the same as that of the second polarizer. The optical axis of the third phase retarder forms a 90° angle with that of the fourth phase retarder, and the optical axis of the first phase retarder is the same as that of the fourth phase retarder. The transmission axis of the third polarizer is the same as that of the polarizing reflective film. The polarizing reflective film transmits P-polarized light and reflects S-polarized light, while any polarizer transmits P-polarized light and absorbs S-polarized light. The transmission axis of the first polarizer is the same as that of the third polarizer. The functions of the components in the first and second polarization conversion components are shown in Table 1 above and will not be repeated here.

[0108] The following will combine Figure 11 The imaging principle of this optical module will be introduced. Figure 11 This is a schematic diagram of the optical path of another optical system provided in an embodiment of the present invention. It should be noted that, since the first lens can directly transmit light without altering the direction or shape of the light rays, this is done to briefly explain the imaging principle. Figure 11 The first lens is not shown in the image; however, the reader should understand that it is actually positioned between the semi-transparent, semi-reflective film and the fourth phase retarder. Its imaging principle is as follows:

[0109] In this process, right-hand circularly polarized light emitted from the display assembly enters the optical module through the third phase retarder. This beam of right-hand circularly polarized light is first converted into P-linearly polarized light by the third phase retarder and then directed towards the third polarizer (…). Figure 11In process 1), since the third polarizer transmits P-polarized light and absorbs S-polarized light, the P-polarized light beam will pass through the third polarizer and strike the polarizing reflective film (process 2). Since the polarizing reflective film transmits P-polarized light and reflects S-polarized light, the P-polarized light beam will pass through the polarizing reflective film and strike the fourth phase retarder (process 3). Since there is a 90° angle between the optical axes of the third and fourth phase retarders, and the transmission axes of the third polarizer and the polarizing reflective film are the same, the P-polarized light beam passing through the two phase retarders is equivalent to passing through a half-wave plate, and the polarization chirality is the same. Therefore, the fourth phase retarder converts the P-polarized light beam into right-handed circularly polarized light, which then strikes the semi-transparent and semi-reflective film (process 4).

[0110] A semi-transparent and semi-reflective film reflects some light while transmitting some light. These two types of light will be described separately below:

[0111] For the light passing through the semi-transparent and semi-reflective membrane:

[0112] First, the transflective film transmits a portion of right-handed circularly polarized light, which is then directed towards the first phase retarder (process 14). Since the transflective film is expected to reflect all light in a pancake-folded optical path, this portion of right-handed circularly polarized light passing through it is also called stray light. The first phase retarder converts this beam of right-handed circularly polarized light into S-polarized light, which is then directed towards the first polarizer (process 15). Because the first polarizer transmits P-polarized light and absorbs S-polarized light, this beam of S-polarized light will be absorbed by the first polarizer (process 16). Furthermore, if the first polarizer does not completely absorb the S-polarized light, the second polarizer will further absorb this portion. In this way, the stray light is extinguished and will not propagate to the display assembly, thus preventing light from reflecting back and forth between the display assembly and the transflective film, thus avoiding stray ghosting.

[0113] For the light reflected by the semi-transparent and semi-reflective film:

[0114] First, the semi-transparent and semi-reflective film reflects a portion of the right-hand circularly polarized light, converting it into left-hand circularly polarized light, which then re-enters the fourth phase retarder (process 5). The fourth phase retarder converts the left-hand circularly polarized light into S-linearly polarized light, which then enters the polarizing reflective film (process 6). Since the polarizing reflective film transmits P-linearly polarized light but reflects S-linearly polarized light, this beam of S-linearly polarized light is reflected by the polarizing reflective film and re-enters the fourth phase retarder (process 7). This beam of S-linearly polarized light is converted into left-hand circularly polarized light by the fourth phase retarder and then enters the semi-transparent and semi-reflective film (process 8).

[0115] When the left-hand circularly polarized light beam strikes the semi-transparent and semi-reflective film, it is split into two beams. That is, the film reflects some of the light while transmitting some. These two beams will be described separately below.

[0116] For the light passing through the semi-transparent and semi-reflective membrane:

[0117] Left-handed circularly polarized light passes through a semi-transparent, semi-reflective film and is directed towards the first phase retarder (process 9). After passing through the first phase retarder, this left-handed circularly polarized light is converted into P-linearly polarized light and is directed towards the first polarizer (process 10). Next, this P-linearly polarized light passes through the first polarizer and is directed towards the second polarizer (process 11). Then, this P-linearly polarized light passes through the second polarizer and is directed towards the second phase retarder (process 12). The second phase retarder then converts the P-linearly polarized light into right-handed circularly polarized light and exits the optical module towards the human eye.

[0118] For the light passing through the semi-transparent and semi-reflective membrane:

[0119] First, left-handed circularly polarized light is reflected by a semi-reflective film, becoming right-handed circularly polarized light, and then directed towards the fourth phase retarder (process 17). Since it is desirable for all light to pass through the semi-reflective film and reach the first phase retarder in the first polarization conversion assembly during this optical path folding, the right-handed circularly polarized light reflected by the film is also called stray light. This right-handed circularly polarized light is converted into P-linearly polarized light by the fourth phase retarder (process 18). This P-linearly polarized light passes through the polarization reflection film and the third polarizer and reaches the third phase retarder, which converts it back into right-handed circularly polarized light and directs it towards the display assembly (process 19). Next, the display assembly reflects the right-handed circularly polarized light, converting it into left-handed circularly polarized light, which then reaches the third phase retarder (process 20). The third phase retarder converts the left-handed circularly polarized light into S-linearly polarized light and directs it towards the third polarizer (process 21). The third polarizer absorbs S-polarized light, eliminating stray light and ghosting propagating towards the human eye (process 22).

[0120] In one possible implementation, embodiments of the present invention provide another optical system. Figure 12 A schematic diagram of the structure of such an optical system is shown as an example. (Refer to...) Figure 12 As shown, the optical system includes not only the optical module and display assembly, but also multiple refractive lenses. Figure 12 In the example, there are four refractive lenses, with multiple refractive lenses located on both sides of the optical module. Furthermore, the multiple refractive lenses are arranged symmetrically about the central axis of the first lens.

[0121] The refractive lens can be positioned directly against the optical module or spaced apart from it; there are no limitations on this. Lens types include, but are not limited to, biconvex lenses, biconcave lenses, and concave-convex lenses. Lens surfaces include, but are not limited to, freeform surfaces, spherical surfaces, and aspherical surfaces. Furthermore, depending on business requirements or application scenarios, anti-reflective coatings can be applied to the surface of the refractive lens to reduce interface reflections.

[0122] In this embodiment of the invention, setting multiple refractive lenses is beneficial for further adjusting the optical imaging effect. In addition, since the multiple refractive lenses are axially symmetrically arranged, when the optical module is assembled into the optical system, the imaging effect is consistent regardless of whether the optical module is assembled from the front or the back, thus further improving the assembly accuracy of the optical module.

[0123] Figure 13 An exemplary optical path diagram of an optical system provided by an embodiment of the present invention is shown. The optical system includes an optical module, a display assembly, and two refractive lenses (refractive lens 1 and refractive lens 2). The display assembly emits light to refractive lens 1, which refracts the light to the optical module. After pancake folding within the optical module, the light is directed to refractive lens 2 and refracted before reaching the user's eye.

[0124] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0125] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0126] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0127] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0128] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. An optical module, characterized in that, The optical module includes, in sequence, a first polarization conversion component, a first lens, and a second polarization conversion component; When circularly polarized light in the first direction enters the optical module from the first polarization conversion component: The first polarization conversion component is used to convert circularly polarized light in the first direction into circularly polarized light in the second direction and send it through the first lens to the second polarization conversion component; the second polarization conversion component is used to reflect the circularly polarized light in the second direction back to the first lens and send it to the first polarization conversion component; the first polarization conversion component is also used to reflect the circularly polarized light in the second direction back into circularly polarized light in the first direction and send the circularly polarized light in the first direction through the first lens to the second polarization conversion component; the second polarization conversion component is also used to emit the circularly polarized light in the first direction. When circularly polarized light in the first direction enters the optical module from the second polarization conversion component: The second polarization conversion component is used to transmit the circularly polarized light in the first direction to the first lens and reach the first polarization conversion component; the first polarization conversion component is used to reflect the circularly polarized light in the first direction into circularly polarized light in the second direction and send the circularly polarized light in the second direction through the first lens to the second polarization conversion component; the second polarization conversion component is also used to reflect the circularly polarized light in the second direction back to the first lens and send it to the first polarization conversion component; the first polarization conversion component is also used to convert the circularly polarized light in the second direction into circularly polarized light in the first direction and send it out.

2. The optical module as described in claim 1, characterized in that, The first polarization conversion component includes a semi-transparent and semi-reflective film and N light conversion components; wherein, N is a positive integer; the semi-transparent and semi-reflective film is disposed on the side close to the first lens, and the light conversion components are disposed on the side away from the first lens; The first side of the light conversion component refers to the side facing the semi-transparent and semi-reflective film, and the second side of the light conversion component refers to the side facing away from the semi-transparent and semi-reflective film. When light shines from the first surface onto the light conversion component, the light conversion component is used to absorb circularly polarized light in the first direction and transmit circularly polarized light in the second direction; When light shines from the second surface onto the light conversion component, the light conversion component is used to transmit circularly polarized light in the first direction and absorb circularly polarized light in the second direction.

3. The optical module as described in claim 2, characterized in that, In the direction from the first surface to the second surface, the optical conversion component sequentially includes a first phase retarder, a first polarizer, and a second phase retarder; The optical axis direction of the first phase retarder is the same as that of the second phase retarder.

4. The optical module as described in claim 3, characterized in that, The optical conversion component further includes a second polarizer, which is located between the first polarizer and the second phase delayer; the direction of the transmission axis of the second polarizer is the same as the direction of the transmission axis of the first polarizer.

5. The optical module as described in claim 3, characterized in that, From the direction away from the first lens to the direction closer to the first lens, the second polarization conversion component sequentially includes a third phase retarder, a third polarizer, a polarizing reflective film, and a fourth phase retarder; The optical axis of the third phase retarder is at a 90° angle to the optical axis of the fourth phase retarder; The optical axis direction of the first phase retarder is the same as that of the fourth phase retarder, or the optical axis direction of the first phase retarder is the same as that of the third phase retarder; The direction of the transmission axis of the third polarizer is the same as the direction of the transmission axis of the polarizing reflective film; The direction of the light transmission axis of the first polarizer is orthogonal to the direction of the light transmission axis of the third polarizer, or the direction of the light transmission axis of the first polarizer is the same as the direction of the light transmission axis of the third polarizer.

6. The optical module as described in claim 1, characterized in that, The radii of curvature of the two surfaces of the first lens are the same in size but opposite in sign.

7. The optical module as described in claim 3 or 5, characterized in that, Any phase delayer can be a quarter-wave plate, or two eighth-wave plates, or four sixteenth-wave plates.

8. The optical module as described in claim 1, characterized in that, The optical module further includes M second lenses, where M is an even number, and the M second lenses are located on both sides of the first polarization conversion component and the second polarization conversion component, respectively. With the central axis of the first lens as the center line, the M second lenses are arranged symmetrically.

9. An optical system, characterized in that, Includes a display assembly and an optical module as claimed in any one of claims 1 to 8; The display assembly is disposed on the side closer to the first polarization conversion assembly, or the display assembly is disposed on the side closer to the second polarization conversion assembly; The display assembly is used to emit circularly polarized light in a first direction.

10. The optical system as claimed in claim 9, characterized in that, The optical system also includes multiple refractive lenses, which are located on both sides of the optical module. With the central axis of the first lens as the center line, the plurality of refractive lenses are arranged symmetrically.

Images