Near-eye display optical system and smart glasses

Abstract

The present invention discloses a near-eye display optical system and smart glasses. The near-eye display optical system includes: a display unit for emitting a light beam; an optical waveguide, the optical waveguide including a coupling-in structure and a coupling-out structure, the coupling-in structure is used to couple the light beam emitted by the display unit into the optical waveguide, and the coupling-out structure is used to couple the light beam in the optical waveguide out; a filter component is arranged on the optical path of the light beam coupled out from the optical waveguide, and is used to filter out stray light in the light beam, the filter component includes a first lens group, a second lens group and an aperture, the aperture is arranged between the first lens group and the second lens group, the aperture is arranged on the focal plane of the first lens group, and the aperture is arranged on the focal plane of the second lens group. According to the near-eye display optical system of the present invention, by arranging the filter component on the optical waveguide coupling-out structure side, the stray light in the optical waveguide can be filtered out, thereby improving the imaging quality of the near-eye display optical system.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to a near-eye display optical system and smart glasses. Background Art

[0002] In recent years, augmented reality (AR) and virtual reality (VR) technologies have developed rapidly. In order to realize the function of augmented reality, researchers have proposed a variety of solutions, such as Birdbath, prism, free-form surface, optical waveguide and other technologies. In the first three solutions, there is often a contradiction between good product form and better display effect, and optical waveguide can effectively solve the above problems. However, in optical waveguide technology, due to processing errors, the surface that limits the total reflection transmission of light in the waveguide is not an ideal plane, which causes the transmitted light to scatter where there are defects on the surface of the waveguide, that is, the stray light generated by the waveguide, which directly causes the decline in the quality of virtual image display. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention is to provide a near-eye display optical system, which can effectively shield the stray light outside the market and improve the imaging quality of the optical waveguide.

[0004] The present invention also provides a pair of smart glasses having the above-mentioned near-eye display optical system.

[0005] According to the near-eye display optical system of the first aspect of the present invention, the near-eye display optical system comprises:

[0006] A display unit, for emitting a light beam;

[0007] An optical waveguide, the optical waveguide comprising a coupling-in structure and a coupling-out structure, the coupling-in structure is used to couple the light beam emitted by the display unit into the optical waveguide, and the coupling-out structure is used to couple the light beam in the optical waveguide out;

[0008] A filter assembly is arranged on the optical path of the light beam coupled out from the optical waveguide, and is used to filter out stray light in the light beam. The filter assembly includes a first lens group, a second lens group and an aperture. The aperture has a light-through hole. The aperture is arranged between the first lens group and the second lens group. The aperture is arranged on the focal plane of the first lens group, and the aperture is arranged on the focal plane of the second lens group. The light beam emitted from the optical waveguide is emitted to the human eye after passing through the first lens group, the aperture and the second lens group.

[0009] In some embodiments, the focal length of the first lens group is f 1, the field angle of the parallel light beam emitted from the optical waveguide is 2α, and the height of the light hole of the aperture is h, where h satisfies: h = f 1 tanα.

[0010] In some embodiments, the filter component is disposed on one side of the optical waveguide.

[0011] In some embodiments, the first lens group and the second lens group are disposed on opposite sides of the optical waveguide, and the near-eye display optical system further includes a reflector disposed on a side of the first lens group away from the optical waveguide.

[0012] In some embodiments, the reflector is a reflective film disposed on the first lens group, and the reflective film is formed on the first lens group through a coating process.

[0013] In some embodiments, the near-eye display optical system further includes a refractive index tunable element, which includes a wedge-shaped prism filled with a refractive index tunable material, and the light beam emitted from the optical waveguide passes through the refractive index tunable element and then is emitted toward the human eye.

[0014] In some optional embodiments, the refractive index adjustable element further includes a positive electrode and a negative electrode disposed on the wedge-shaped prism, the refractive index adjustable material is electrically connected to the positive electrode and the negative electrode, and the refractive index of the refractive index adjustable material is controlled by adjusting the voltage between the positive electrode and the negative electrode.

[0015] In some optional embodiments, the refractive index adjustable element is arranged at the light hole of the aperture.

[0016] In some optional embodiments, the refractive index tunable material is liquid crystal.

[0017] According to the near-eye display optical system of the present invention, a filter component is arranged on the side of the optical waveguide coupling structure, and the light coupled out of the optical waveguide is emitted to the human eye after passing through the filter component, thereby filtering out the stray light in the optical waveguide, thereby improving the imaging quality of the near-eye display optical system. In addition, the filter component composed of the first lens group, the second lens group and the aperture is used, and the structure of the filter component is simple and easy to manufacture, which is conducive to simplifying the structure of the near-eye display optical system and reducing the difficulty of assembling the near-eye display optical system.

[0018] The smart glasses according to the second aspect of the present invention include the near-eye display optical system according to the first aspect of the present invention.

[0019] According to the smart glasses of the present invention, the near-eye display optical system of the first aspect is provided, thereby improving the overall performance of the smart glasses.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of a near-eye display optical system according to an embodiment of the present invention;

[0022] Figure 2 is a schematic diagram of a near-eye display optical system according to another embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of a filter assembly according to an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the principle of human eyes distinguishing the distance of objects;

[0025] Figure 5 is a schematic diagram of a refractive index tunable element according to an embodiment of the present invention;

[0026] Figure 6 is a schematic diagram of a near-eye display optical system according to yet another embodiment of the present invention;

[0027] Figure 7 is a schematic diagram of smart glasses according to an embodiment of the present invention.

[0028] Reference numerals:

[0029] 100 near-eye display optical system; 10 display unit; 20 optical waveguide; 21 coupling structure; 22 coupling structure; 30 filter assembly; 31 first lens group; 32 aperture; 321; light hole; 33 second lens group; 34 reflector; 40 refractive index adjustable element; 41 wedge prism; 42 refractive index adjustable material; a stray light; b optical axis;

[0030] 1,000 smart glasses; 200 frames; 300 temples; 400 human eyes. DETAILED DESCRIPTION

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0032] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, 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 invention. In addition, the present invention can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific processes and examples of materials, but those of ordinary skill in the art can be aware of the applicability of other processes and / or the use of other materials.

[0033] Reference below Figure 1-Figure 6 A near-eye display optical system 100 according to an embodiment of the present invention is described. The near-eye display optical system 100 may include a display unit 10 and an optical waveguide 20. The display unit 10 is used to emit a light beam. For example, the display unit 10 may emit a light beam that forms a virtual image. The light beam that forms the virtual image is transmitted through the optical waveguide 20 and enters the human eye 400, thereby achieving a virtual reality display effect. At the same time, if light in the real world passes through the optical waveguide 20 and enters the human eye 400, the human eye 400 can observe the virtual image and the real world at the same time, thereby achieving an augmented reality effect.

[0034] It can be understood that the near-eye display optical system 100 in the embodiment of the present invention can be used with a variety of display units 10. Specifically, for example, the display unit 10 can include a micro organic light emitting diode (Micro OLED) display, a micro light emitting diode (Micro LED) display or a liquid crystal (LC) display. Furthermore, the micro organic light emitting diode, micro light emitting diode or liquid crystal display can all be silicon-based displays. The silicon-based display is based on a single crystal silicon wafer, and the pixel size is about 1 / 10 of that of a traditional display. It has the advantages of low power consumption, small size, and high resolution. It is very suitable for a near-eye display optical system 100 for close observation. Of course, the display unit 10 can also be other types of displays, which are not limited by the embodiment of the present invention.

[0035] Furthermore, the optical waveguide 20 in the near-eye display optical system 100 includes a coupling-in structure 21 and a coupling-out structure 22, and the coupling-in structure 21 and the coupling-out structure 22 are arranged at opposite ends of the optical waveguide 20. It can be understood that the light beam emitted by the display unit 10 is transmitted in the optical waveguide 20 by total reflection. Therefore, when the light beam enters the optical waveguide 20, after the light beam passes through the coupling-in structure 21, the incident angle of the coupled-in light beam reaches the condition of total reflection, so that the light beam can be transmitted in the optical waveguide 20 by total reflection. When the light beam is transmitted to the coupling-out structure 22, the coupling-out structure 22 can destroy the total reflection condition of the light beam, so that the light beam is emitted from the optical waveguide 20. Specifically, the coupling-in structure 21 may be a structure such as a grating, a prism, a reflector 34, and the coupling-out structure 22 may be a structure such as a grating, an array of semi-reflective and semi-mirror, and the like. The embodiment of the present invention does not limit the specific structures of the coupling-in structure 21 and the coupling-out structure 22. The coupling-in structure 21 may be the same as the coupling-out structure 22, for example, the coupling-in structure 21 and the coupling-out structure 22 are both gratings. The coupling-in structure 21 may also be different from the coupling-out structure 22, for example, the coupling-in structure 21 is a grating, and the coupling-out structure 22 is an array of semi-reflective and semi-mirror, and the like.

[0036] Furthermore, the near-eye display optical system 100 also includes a filter component 30 , which is disposed on the optical path of the light beam coupled out from the optical waveguide 20 , that is, the light beam emitted from the optical waveguide 20 is emitted toward the human eye 400 after passing through the filter component 30 .

[0037] Furthermore, the filter assembly 30 includes a first lens group 31, a second lens group 33 and an aperture 32. It can be understood that the first lens group 31 can be one lens, two lenses or multiple lenses, etc. The embodiment of the present invention does not limit the number of lenses in the first lens group 31. Similarly, the number of lenses in the second lens group 33 can also be one lens, two lenses or multiple lenses, etc.

[0038] Further, the aperture 32 is arranged between the first lens group 31 and the second lens group 33, the aperture 32 is arranged on the focal plane of the first lens group 31, and the aperture 32 is arranged on the focal plane of the second lens group 33. That is, the aperture 32 is arranged on the image-side focal plane of the first lens group 31, and the aperture 32 is arranged on the object-side focal plane of the second lens group 33, the image-side focal plane of the first lens group 31 coincides with the object-side focal plane of the second lens group 33, the aperture 32 is provided with a light-through hole 321, the first lens group 31 and the second lens group 33 have the same optical axis b, and the center of the light-through hole 321 of the aperture 32 is located on the optical axis b.

[0039] Further, the light beam of the virtual image emitted from the optical waveguide 20 is emitted toward the human eye 400 after passing through the first lens group 31, the aperture 32 and the second lens group 33. Specifically, when the light beam emitted from the optical waveguide 20 passes through the first lens group 31, parallel light of different angles will be focused to different positions on the image-side focal plane of the first lens group 31. At this time, since the aperture 32 is set at the image-side focal plane of the first lens group 31, the stray light a outside the field of view will be blocked by the aperture 32, and the light within the field of view passes through the light hole 321 of the aperture 32 and then passes through the second lens group 33 and becomes parallel light of different angles again.

[0040] Furthermore, the filter component 30 is used to filter out stray light a in the light beam. It should be noted that when the light beam propagates by total reflection in the optical waveguide 20, since the two relative planes of the optical waveguide 20 are not absolutely parallel or absolutely smooth, when the light emitted by the display unit 10 enters the waveguide for transmission, additional stray light a will be generated, thereby affecting the imaging quality of the near-eye display optical system 100.

[0041] According to the near-eye display optical system 100 of the present application, since the filter component 30 is arranged on the side of the coupling structure 22 of the optical waveguide 20, the light coupled out of the optical waveguide 20 is emitted to the human eye 400 after passing through the filter component 30, thereby filtering out the stray light a in the optical waveguide 20, improving the imaging quality of the near-eye display optical system 100, and utilizing the filter component 30 composed of the first lens group 31, the second lens group 33 and the aperture 32. The filter component 30 has a simple structure and is easy to manufacture, which is conducive to simplifying the structure of the near-eye display optical system 100 and reducing the difficulty of assembling the near-eye display optical system 100.

[0042] Please refer to Figure 1-Figure 3 As shown, in some embodiments, the focal length of the first lens group 31 is f 1 , the field angle of the parallel light beam emitted from the optical waveguide 20 is 2α, and the height of the light hole 321 of the aperture 32 is h, where h satisfies: h = f 1 tanα. Thus, by designing the height of the light hole 321 of the aperture 32, more stray light a can be removed while ensuring that the aperture 32 does not affect the field of view of the near-eye display optical system 100, thereby further improving the imaging quality of the near-eye display optical system 100. Furthermore, if the height of the light hole 321 of the aperture 32 is greater than f 1 When tanα, some stray light a will still enter the human eye 400 through the light hole 321 of the aperture 32, reducing the imaging quality. 1 When tanα, the aperture 32 will block the light beam of the virtual image in part of the field of view from entering the human eye 400, thereby causing the image to be partially confirmed or the image quality to be reduced.

[0043] It should be noted that when the first lens group 31 is a single lens, the focal length f of the first lens group 31 is 1 is the focal length of the lens. When the first lens group 31 is composed of two or more lenses, the focal length f of the first lens group 31 is 1 is the effective focal length of the first lens group 31. The light hole 321 of the aperture 32 may be in a circular, square, rectangular or other shape. The embodiment of the present invention does not limit the shape of the light hole 321 of the aperture 32. For example, when the light hole 321 of the aperture 32 is circular, the height h of the light hole 321 of the aperture 32 may be the diameter of the light hole 321. When the light hole 321 of the aperture 32 is square or rectangular, the height h of the light hole 321 of the aperture 32 may be the length or width of the square or rectangle.

[0044] like Figure 1 As shown, in some embodiments, the filter assembly 30 is disposed on one side of the optical waveguide 20. Thus, the difficulty of assembling the filter assembly 30 and the optical waveguide 20 can be reduced, and the structure of the near-eye display optical system 100 can be simplified.

[0045] It can be understood that the filter component 30 is arranged on one side of the optical waveguide 20, which means that the first lens group 31, the second lens group 33 and the aperture 32 are all arranged on the same side of the optical waveguide 20. For example, the filter component 30 can be arranged on the side of the optical waveguide 20 close to the human eye 400, or the filter component 30 can be arranged on the side of the optical waveguide 20 away from the human eye 400. The embodiment of the present invention is not limited to this, as long as the light emitted from the optical waveguide 20 can filter out the stray light a and emit to the human eye 400 after passing through the filter component 30.

[0046] Please refer to Figure 2 In some embodiments, the first lens group 31 and the second lens group 33 are arranged on opposite sides of the optical waveguide 20. Specifically, for example, the first lens group 31 can be arranged on a side of the optical waveguide 20 away from the human eye 400, the aperture 32 is arranged on a side of the optical waveguide 20 close to the human eye 400, and the aperture 32 is arranged on the focal plane of the first lens, and the second lens group 33 is also arranged on a side of the optical waveguide 20 close to the human eye 400, and the aperture 32 is also arranged on the focal plane of the second lens, that is, the image-side focal plane of the first lens group 31 coincides with the object-side focal plane of the second lens group 33, the aperture 32 is arranged on the image-side focal plane of the first lens group 31, and the aperture 32 is arranged on the object-side focal plane of the second lens group 33.

[0047] Please continue to refer to Figure 2Furthermore, the near-eye display optical system 100 further includes a reflector 34, which is disposed on a side of the first lens group 31 away from the optical waveguide 20. Therefore, after the light beam is emitted from the optical waveguide 20 through the outcoupling structure 22, it is emitted to the reflector 34 after passing through the first lens group 31, and after being reflected by the reflector 34, it passes through optical elements such as the first lens group 31, the aperture 32, and the second lens group 33, and finally emitted to the human eye 400.

[0048] It can be understood that by respectively arranging the first lens group 31 and the second lens group 33 on opposite sides of the optical waveguide 20, the optical elements of the near-eye display optical system 100 can be distributed more evenly, thereby making the weight distribution of the near-eye display optical system 100 more even, improving the user experience, and helping to reduce the size of the near-eye display optical system 100.

[0049] It should be noted that the reflector 34 can be arranged in close contact with the first lens group 31, so as to further reduce the size of the near-eye display optical system 100. Of course, the embodiment of the present invention does not limit the location of the reflector 34, as long as the light beam emitted from the optical waveguide 20 passes through the first lens group 31, is reflected by the reflector 34, and then passes through the first lens group 31, the aperture 32, the second lens group 33 and other optical elements, and finally can be emitted to the human eye 400, and the stray light a and can be removed.

[0050] In some embodiments, the reflector 34 is a reflective film disposed on the first lens group 31, and the reflective film is formed on the first lens group 31 through a coating process. Thus, the size and weight of the near-eye display optical system 100 can be further reduced, and the user experience can be further improved.

[0051] It can be understood that a reflective film is formed on the surface of the first lens group 31 away from the optical waveguide 20 by a coating process. For example, a vacuum evaporation coating, magnetron sputtering coating or other processes can be used to form the reflective film on the surface of the first lens group 31 away from the optical waveguide 20.

[0052] It should be noted that, since the reflective film reflects light, the reflective film can block the light from the real world from passing through the optical waveguide 20 and entering the human eye 400. At this time, the near-eye display optical system 100 can be a virtual reality (VR) optical system. On the other hand, when the reflectivity of the reflective film is reduced, while reflecting the light emitted from the optical waveguide 20, it can also transmit the light from the real world, so that the light from the real world can pass through the optical waveguide 20 and enter the human eye 400. At this time, the near-eye display optical system 100 can be an augmented reality (AR) optical system.

[0053] Furthermore, the reflective film can also be formed of an electrochromic material, so that the reflectivity of the reflective film can change under the action of voltage, so that the near-eye display optical system 100 can switch between a virtual reality optical system and an augmented reality optical system, thereby broadening the scope of use of the near-eye display optical system 100 and further improving the user experience.

[0054] like Figure 4 As shown, Figure 4 The principle of the human eye 400 in distinguishing the distance of an object is given. It should be noted that for an object at a distance D, when the left and right eyes of the human body observe, there will be an opening angle θ. When the distance of the observed object becomes D', the opening angle becomes θ'. The change in the opening angle enables the human eye 400 to perceive the distance. Therefore, in the near-eye display optical system 100, the control of the display distance of the virtual image is achieved by adjusting the angle between the left and right lenses. For example, the angle of the light rays in the central field of view received by the left and right eyes can be changed by adjusting the mechanical structure. However, once the mechanical structure is fixed, the display depth of the virtual image is fixed, and the display depth of the virtual image cannot be adjusted. There is still a problem of visual convergence conflict.

[0055] Please refer to Figure 5-Figure 6 In some embodiments, the near-eye display optical system 100 further includes a refractive index tunable element 40, which includes a wedge-shaped prism 41, and the wedge-shaped prism 41 is filled with a refractive index tunable material 42. The light beam emitted from the optical waveguide 20 passes through the refractive index tunable element 40 and then is emitted to the human eye 400. Of course, the wedge-shaped prism 41 itself may also be made of the refractive index tunable material 42, and the embodiment of the present invention is not limited to this.

[0056] It can be understood that the wedge prism 41 is a transparent optical element with a wedge-shaped cross section, and the distance between the two opposite planes of the wedge prism 41 gradually changes, thereby forming a wedge shape, that is, the thickness of the wedge prism 41 gradually changes. The wedge prism 41 is mainly used in the field of optics to control the deviation of light beams. When light passes through an optical element, due to the different propagation speeds of light in different media, the light will be refracted, and the light will also be deflected when passing through the wedge prism 41. The wedge angle of the wedge prism 41 refers to the angle at the top of the prism. The size of the wedge angle directly affects the deflection angle of the light. When the light passes through the wedge prism 41, the size of the angle between the incident angle of the light and the exit angle of the light (that is, the deflection angle) is also related to the wedge angle of the wedge prism 41 and the refractive index of the wedge prism 41. For example, the wedge angle of the wedge prism 41 is β, the deflection angle of the light is δ, the refractive index of the refractive index adjustable material 42 filled in the wedge prism 41 is n, and the deflection angle δ of the light satisfies: δ = (n-1) β.

[0057] It can be seen from the above formula that the deflection angle δ of the outgoing light relative to the incident light is affected by two factors: the wedge angle β and the refractive index n. Therefore, the refractive index adjustable material 42 can be filled in the wedge prism 41, so that n in the above formula can be changed, thereby adjusting the deflection angle δ of the light. When the light is deflected, the opening angle θ of the light incident on the human eye 400 changes, thereby changing the display depth of the virtual image, which is conducive to improving the problem of visual convergence conflict.

[0058] It should be noted that the refractive index adjustable element 40 can be arranged in front of the filter component 30, that is, the light beam emitted from the optical waveguide 20 passes through the refractive index adjustable element 40, then enters the filter component 30, and finally emits to the human eye 400. Alternatively, the refractive index adjustable element 40 can also be arranged after the filter component 30, and the light beam emitted from the optical waveguide 20 passes through the filter component 30, then emits to the refractive index adjustable element 40, and finally emits to the human eye 400. The embodiment of the present invention does not limit the setting position of the refractive index adjustable element 40.

[0059] It can be understood that, according to the above formula, the size of the deflection angle is also related to the size of the wedge angle of the wedge prism 41. Therefore, the two planes of the wedge prism 41 can also be set as two movably connected planes, and a driving member is set on one of the planes. When the driving member is working, the driving member can drive one plane in the wedge prism 41 to move, thereby changing the size of the wedge angle of the wedge prism 41, thereby realizing the regulation of the size of the deflection angle.

[0060] In some optional embodiments, the refractive index tunable element 40 further includes a positive electrode and a negative electrode disposed on the wedge-shaped prism 41, and the refractive index tunable material 42 is electrically connected to the positive electrode and the negative electrode, and the voltage between the positive electrode and the negative electrode is adjusted to control the refractive index of the refractive index tunable material 42. Thus, the refractive index of the refractive index tunable element 40 is adjusted by voltage, the structure is simple, the adjustment method is simple, and the structure of the near-eye display optical system 100 can be further simplified.

[0061] Specifically, a positive electrode and a negative electrode can be placed on two opposite surfaces of the wedge prism 41, respectively. The refractive index adjustable element 40 is arranged on the side of the coupling-out structure 22 of the optical waveguide 20, and there is an air gap between the refractive index adjustable element 40 and the optical waveguide 20, that is, the refractive index adjustable element 40 is not completely in contact with the optical waveguide 20. Since the refractive index of air is smaller than that of the optical waveguide 20, when light is transmitted from the air to the refractive index adjustable element 40, the adjustable range of the refractive index of the refractive index adjustable element 40 relative to that of the air is larger, thereby further increasing the modulation degree of the depth adjustment of the near-eye display optical system 100.

[0062] Please continue to refer to Figure 6In some optional embodiments, the refractive index tunable element 40 is disposed at the light hole 321 of the aperture 32. Thus, the filter assembly 30 of the near-eye display optical system 100 and the refractive index tunable element 40 can be cleverly combined, and the size of the near-eye display optical system 100 can be further reduced while the stray light a can be filtered out and the virtual image display depth can be adjusted.

[0063] It should be noted that the shape of the light hole 321 of the aperture 32 in the filter assembly 30 can be designed to be the same as or similar to the wedge-shaped prism 41, so that the wedge-shaped prism 41 can be engaged or bonded in the light hole 321 of the aperture 32. Of course, the embodiment of the present invention is not limited to this, and the light hole 321 of the aperture 32 can also be other shapes, as long as the wedge-shaped prism 41 can be set in the light hole 321.

[0064] In some embodiments, the refractive index adjustable element 40 may not be arranged in the light-transmitting hole 321. For example, the refractive index adjustable element 40 may be directly attached to the aperture 32. After the light passes through the refractive index adjustable element 40, it is emitted through the light-transmitting hole 321 of the aperture 32. Alternatively, the light first passes through the light-transmitting hole 321 of the aperture 32 and then passes through the refractive index adjustable element 40 to be emitted.

[0065] In some optional embodiments, the refractive index tunable material 42 is liquid crystal. Therefore, the preparation method of the liquid crystal material is simple and the preparation process is mature, so the manufacturing process of the near-eye display optical system 100 can be simplified and the production cost can be reduced.

[0066] Specifically, the refractive index adjustable element 40 includes a wedge-shaped prism 41, which is filled with liquid crystal, and the refractive index of the liquid crystal changes with the change of the external voltage. Therefore, after the light is emitted from the optical waveguide 20, it is emitted to the refractive index adjustable element 40. When the magnitude of the external voltage applied to the liquid crystal is changed, the magnitude of the refractive index of the liquid crystal is controlled, so that the exit angle of the light after passing through the refractive index adjustable element 40 changes. When the light is incident on the human eye 400, the opening angle of the virtual image perceived by the human eye 400 changes, thereby achieving the adjustment of the display depth of the virtual image.

[0067] It is understandable that the refractive index tunable material 42 may also be other electro-optical materials, and the embodiment of the present invention is not limited thereto, as long as it is light-transmissive and its refractive index can change under the action of an external voltage.

[0068] Please refer to Figure 7, a smart glasses 1000 according to an embodiment of the present invention comprises: the above-mentioned near-eye display optical system 100. The smart glasses 1000 may further comprise a frame 200 and temples 300. The optical waveguide 20 and the filter assembly in the near-eye display optical system 100 may be arranged in the frame 200, and the display unit 10 may be arranged on the temples 300, so that the weight distribution of the smart glasses 1000 is more uniform, thereby improving the user experience. Specifically, when the smart glasses 1000 are binocular, the smart glasses 1000 may be provided with two frames 200, and at this time, both frames 200 may be provided with optical waveguides 20. It can be understood that since the filter component 30 is set on the side of the coupling structure 22 of the optical waveguide 20, the light coupled out of the optical waveguide 20 is emitted to the human eye 400 after passing through the filter component 30, thereby filtering out the stray light a in the optical waveguide 20, improving the imaging quality of the near-eye display optical system 100, and utilizing the filter component 30 composed of the first lens group 31, the second lens group 33 and the aperture 32. The filter component 30 has a simple structure and is easy to manufacture, which is conducive to simplifying the structure of the near-eye display optical system 100 and reducing the difficulty of assembling the near-eye display optical system 100, thereby improving the overall performance of the smart glasses 1000.

[0069] Other structures and operations of the near-eye display optical system 100 and the smart glasses 1000 according to the embodiment of the present invention are known to ordinary technicians in the field and will not be described in detail here.

[0070] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0071] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0072] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0074] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do 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. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0075] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A near-eye display optical system, characterized in that: include: A display unit, for emitting a light beam; An optical waveguide, the optical waveguide comprising a coupling-in structure and a coupling-out structure, the coupling-in structure is used to couple the light beam emitted by the display unit into the optical waveguide, and the coupling-out structure is used to couple the light beam in the optical waveguide out; A filter assembly is arranged on the optical path of the light beam coupled out from the optical waveguide, and is used to filter out stray light in the light beam. The filter assembly comprises a first lens group, a second lens group and an aperture. The aperture has a light-through hole. The aperture is arranged between the first lens group and the second lens group. The aperture is arranged on the focal plane of the first lens group, and the aperture is arranged on the focal plane of the second lens group. The light beam emitted from the optical waveguide is emitted to the human eye after passing through the first lens group, the aperture and the second lens group. The focal length of the first lens group is f1, the field angle of the parallel light beam emitted from the optical waveguide is 2α, and the height of the light hole of the aperture is h, where h satisfies: h=f1tanα.

2. The near-eye display optical system according to claim 1, characterized in that: The filter component is arranged on one side of the optical waveguide.

3. The near-eye display optical system according to claim 1, characterized in that: The first lens group and the second lens group are arranged on two opposite sides of the optical waveguide. The near-eye display optical system also includes a reflector, which is arranged on a side of the first lens group away from the optical waveguide.

4. The near-eye display optical system according to claim 3, characterized in that: The reflector is a reflective film disposed on the first lens group, and the reflective film is formed on the first lens group through a coating process.

5. The near-eye display optical system according to any one of claims 1 to 4, characterized in that: It also includes a refractive index adjustable element, which includes a wedge-shaped prism filled with a refractive index adjustable material. The light beam emitted from the optical waveguide passes through the refractive index adjustable element and then is emitted to the human eye.

6. The near-eye display optical system according to claim 5, characterized in that: The refractive index adjustable element also includes a positive electrode and a negative electrode arranged on the wedge prism, and the refractive index adjustable material is electrically connected to the positive electrode and the negative electrode. The refractive index of the refractive index adjustable material is controlled by adjusting the voltage between the positive electrode and the negative electrode.

7. The near-eye display optical system according to claim 5, characterized in that: The refractive index adjustable element is arranged at the light hole of the aperture.

8. The near-eye display optical system according to claim 5, characterized in that: The refractive index tunable material is liquid crystal.

9. A smart glasses, characterized in that: include: A near-eye display optical system as described in any one of claims 1 to 8.

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