Head-mounted display optical system and head-mounted display device

Abstract

The invention discloses a head-mounted display optical system and head-mounted display equipment. The head-mounted display optical system comprises an exit pupil part, a cylindrical cemented lens and a display, the cylindrical cemented lens comprises a first lens, a second lens, a reflective polarizing film, a quarter-wave plate and a semi-transparent and semi-reflective film. The first lens and the second lens are sequentially arranged between the exit pupil part and the display; the reflective polarizing film is mounted on one surface, close to an exit pupil part, of the first lens, the cylindrical surface of the first lens is glued to the second lens, the quarter-wave plate is mounted between the first lens and the second lens, and the semi-transparent and semi-reflective film is mounted on one surface, close to a display, of the second lens; a cover plate piece is installed on the face, close to the second lens, of the displayer. A polaroid is installed between the displayer and the cover plate piece. Compared with the prior art, the lens gluing difficulty is reduced, the optical performance of the optical system is improved, the number of the lenses is reduced, and the size and weight of the optical system are reduced, so that the light weight of the head-mounted display equipment is realized, and the wearing comfort is improved.

Description

Technical Field

[0001] This invention relates to the field of projection display technology, and in particular to a head-mounted display optical system and a head-mounted display device. Background Technology

[0002] With the rapid development of optical technology, users have increasingly higher requirements for head-mounted display devices. In the design of the optical system of head-mounted display devices, to address the issues of system size and light loss, cemented lenses are typically used to fold the optical path, reducing gaps between lenses and reflection losses. However, using curved cementing between lenses increases the difficulty of manufacturing processes and eliminating stray light; while using planar cementing reduces the variables for lens optimization, which is detrimental to improving the performance of the optical system.

[0003] Therefore, it is necessary to provide a head-mounted display optical system and a head-mounted display device to solve the above problems. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a head-mounted display optical system and a head-mounted display device, which can effectively solve the problems of difficult lens bonding, poor optical performance optimization, and relatively large size and weight of the optical system.

[0005] To achieve the above objectives, a first aspect of the present invention provides a head-mounted display optical system, comprising an exit pupil, a cemented cylindrical lens, and a display; the cemented cylindrical lens includes a first lens, a second lens, a reflective polarizing film, a quarter-wave plate, and a semi-transparent film; the first lens and the second lens are sequentially mounted between the exit pupil and the display; the reflective polarizing film is mounted on the side of the first lens near the exit pupil, the first lens is cemented cylindrically to the second lens, the quarter-wave plate is mounted between the first lens and the second lens, and the semi-transparent film is mounted on the side of the second lens near the display; a cover plate is mounted on the side of the display near the second lens, and a polarizing film is mounted between the display and the cover plate.

[0006] In a preferred embodiment, the cylindrical surface of the cemented cylindrical lens is curved in the horizontal direction and flat in the vertical direction.

[0007] In a preferred embodiment, the effective focal length of the head-mounted display optical system is F, the effective focal length of the first lens in the horizontal direction is F1, the effective focal length of the first lens in the vertical direction is F2, the effective focal length of the second lens in the horizontal direction is F3, and the effective focal length of the second lens in the vertical direction is F4, satisfying: -3.015≤F1 / F≤-2.895;-3.217≤F2 / F≤-3.018;3.057≤F3 / F≤3.314;3.317≤F4 / F≤3.610;

[0008] In a preferred embodiment, the refractive index of the first lens is N1, the Abbe number of the first lens is V1, the refractive index of the second lens is N2, and the Abbe number of the second lens is V2, satisfying: 1.012≤N1 / N2≤3.610; 0.486≤V1 / V2≤0.913.

[0009] In a preferred embodiment, the center thickness of the head-mounted display optical system is D, the center thickness of the first lens is D1, and the center thickness of the second lens is D2. 2， satisfy: 0 < D ≤ 12 mm, 0.165 ≤ D1 / D ≤ 0.197, 0.721 ≤ D2 / D ≤ 0.777.

[0010] In a preferred embodiment, the head-mounted display optical system further includes a third lens bonded to the first lens, and a reflective polarizing film is mounted between the third lens and the first lens.

[0011] In a preferred embodiment, the effective focal length of the head-mounted display optical system is F5, the effective focal length of the first lens in the horizontal direction is F6, the effective focal length of the first lens in the vertical direction is F7, the effective focal length of the second lens in the horizontal direction is F8, the effective focal length of the second lens in the vertical direction is F9, and the effective focal length of the third lens is F... 10； satisfy: -5.978≤F6 / F5≤-5.587; -6.455≤F7 / F5≤-5.587; 3.910≤F8 / F5≤4.162; 4.165≤F9 / F5≤4.468; 4.885≤F 10 / F5≤5.023.

[0012] In a preferred embodiment, the refractive indices of the first lens, the second lens, and the third lens are N3, N4, and N5, respectively, and the Abbe numbers of the first lens, the second lens, and the third lens are V3, V4, and V5, respectively, satisfying: 3.309<N3*N4*N5≤3.647;7.571<V3*V4*V5 / 10000≤14.422.

[0013] In a preferred embodiment, the center thickness of the head-mounted display optical system is D3, the center thickness of the first lens is D4, the center thickness of the second lens is D5, and the center thickness of the third lens is D6, satisfying: 0 < D3 ≤ 18 mm, 0.301 ≤ D4 / D3 ≤ 0.412, 0.111 ≤ D5 / D3 ≤ 0.139, and 0.434 ≤ D6 / D3 ≤ 0.502.

[0014] A second aspect of the present invention provides a head-mounted display device comprising the head-mounted display optical system of any of the preceding claims.

[0015] The beneficial effects of this invention are as follows: by setting a cylindrical cemented lens, and utilizing the principle of cylindrical cementation between the first lens and the second lens and the pancake folding optical path, the difficulty of lens cementation is reduced, the optical performance of the optical system is improved, the number of lenses is reduced, and the size and weight of the optical system are reduced, thereby achieving lightweighting of the head-mounted display device and improving wearing comfort. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the first horizontal structure of the head-mounted display optical system provided in an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the first vertical structure of the head-mounted display optical system provided in an embodiment of the present invention.

[0018] Figure 3 This is a first exploded structural diagram of the head-mounted display optical system provided in an embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the second horizontal structure of the head-mounted display optical system provided in an embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of the second vertical structure of the head-mounted display optical system provided in an embodiment of the present invention.

[0021] Figure 6 This is a second exploded view of the optical system for a head-mounted display provided in an embodiment of the present invention. Detailed Implementation

[0022] In this invention, the terms "set up," "equipped with," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0025] 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 and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] This invention provides a head-mounted display optical system and a head-mounted display device, which reduces the difficulty of lens bonding, improves the optical performance of the optical system, optimizes the imaging effect, reduces the number of lenses, and reduces the size and weight of the optical system, thereby achieving lightweighting of the head-mounted display device and improving wearing comfort.

[0027] The following is the content of the first aspect of the present invention: Please refer to Figures 1 to 3 The head-mounted display optical system provided in this embodiment includes an exit pupil 1, a cemented cylindrical lens 2, and a display 3; the cemented cylindrical lens 2 includes a first lens 21, a second lens 22, a reflective polarizing film 23, a quarter-wave plate 24, and a semi-transparent and semi-reflective film 25. Among them, the reflective polarizing film 23 is used to reflect P-polarized light.

[0028] A first lens 21 and a second lens 22 are sequentially mounted between the exit pupil 1 and the display 3. A reflective polarizing film 23 is mounted on the side of the first lens 21 near the exit pupil 1. The cylindrical surface of the first lens 21 is cemented to the second lens 22. A quarter-wave plate 24 is mounted between the first lens 21 and the second lens 22. A semi-transparent, semi-reflective film 25 is mounted on the side of the second lens 22 near the display 3. A cover plate 31 is mounted on the side of the display 3 near the second lens 22, and a polarizer 32 is mounted between the display 3 and the cover plate 31. The cover plate 31 is a glass plate. It is easy to understand that by sequentially mounting the polarizer 32 and the cover glass onto the display 3, the light emitted by the display 3 can be directly converted into circularly polarized light, simplifying the optical path.

[0029] Specifically, the head-mounted display optical system provided in this embodiment is designed based on the principle of pancake folded optical path. To better illustrate the head-mounted display optical system provided in this embodiment, preferred parameters of the head-mounted display optical system are listed here for explanation. These parameters can be selected and replaced according to design requirements, and no further restrictions are imposed. Preferably, to improve the system resolution, the display 3 is preferably a rectangular Micro OLED display screen, with the horizontal field of view and vertical field of view set to 37.63° and 32.49° respectively, and the diameter of the exit pupil 1 set to 8mm; to control the size of the system, the exit pupil distance is set to 15mm.

[0030] Both the side of the first lens 21 near the exit pupil 1 and the side of the second lens 22 near the display 3 are aspherical. The cemented cylindrical surfaces of both the first lens 21 and the second lens 22 are constructed using annular surfaces. A quarter-wave plate 24 is bonded between the first lens 21 and the second lens 22. The quarter-wave plate 24 requires a bonding process to attach it between the first lens 21 and the second lens 22. The cylindrical bonding method used for the first lens 21 and the second lens 22, compared to curved bonding, effectively improves the bonding quality and efficiency of the quarter-wave plate 24 without introducing stray light or affecting the optimization of the cemented lens group, ensuring the optical effect of the quarter-wave plate 24 and reducing the difficulty of lens bonding.

[0031] The optical path of the head-mounted display optical system provided in this embodiment is as follows: After the display 3 emits light, the light passes through the polarizer 32 and the cover plate 31. After the light passes through the polarizer 32 and the cover plate 31, the light is converted into right circularly polarized light (for the sake of explaining the optical path principle, it is assumed here that it is converted into right circularly polarized light, but this is not a limitation). The right circularly polarized light enters the second lens 22 through the semi-transparent and semi-reflective film 25. After passing through the second lens 22, it is transmitted by the quarter-wave plate 24. The quarter-wave plate 24 then converts the circularly polarized light into P-polarized light. When the P-polarized light penetrates the first lens 21, it is reflected along the optical path under the action of the reflective polarizing film 23. When the P-polarized light penetrates the first lens 21 and passes through the quarter-wave plate 24, the P-polarized light is converted into right circularly polarized light. The right circularly polarized light penetrates the second lens 22 and is projected onto the semi-transparent and semi-reflective film 25. After being emitted by the semi-transparent and semi-reflective film 25, the right circularly polarized light is converted into left circularly polarized light. The left circularly polarized light then passes through the second lens 22 and the quarter-wave plate 24 in sequence, and is converted into S-polarized light. The S-polarized light passes through the first lens 21 and the reflective polarizing film 23, and finally enters the exit pupil 1.

[0032] Understandably, by using a cylindrical cemented lens 2, the difficulty of lens cementation is reduced, the optical performance of the optical system is improved, the imaging effect of the optical system is optimized, the number of lenses is reduced, and the size and weight of the optical system are reduced, thereby achieving lightweighting of the head-mounted display device and improving wearing comfort.

[0033] For further details, please refer to... Figures 1 to 3 In one embodiment, the cylindrical surface of the cemented cylindrical lens 2 is curved in the horizontal direction and flat in the vertical direction.

[0034] Specifically, the side of the first lens 21 closest to the second lens 22 is a convex cylindrical surface, and the side of the second lens 22 closest to the first lens 21 is a concave cylindrical surface. The vertical direction of the cylindrical surface is the axis. The side of the first lens 21 closest to the exit pupil 1 has negative optical power, and the convex cylindrical surface of the first lens 21 has positive optical power.

[0035] Since the horizontal field of view of the display 3 is greater than the vertical field of view, more compensation is needed in the horizontal direction. Therefore, the cylindrical surface of the cemented cylindrical lens 2 is curved in the horizontal direction, while the cylindrical surface of the cemented cylindrical lens 2 is horizontal in the vertical direction.

[0036] It is understandable that by setting the cylindrical surface of the cemented lens 2 as a curved surface in the horizontal direction and a flat surface in the vertical direction, the cementation difficulty can be effectively reduced, while the field of view of the head-mounted display optical system can be increased to a certain extent, thereby improving the resolution of the head-mounted display optical system.

[0037] Furthermore, in one embodiment, the effective focal length of the head-mounted display optical system is F, the effective focal length of the first lens 21 in the horizontal direction is F1, the effective focal length of the first lens 21 in the vertical direction is F2, the effective focal length of the second lens 22 in the horizontal direction is F3, and the effective focal length of the second lens 22 in the vertical direction is F4, satisfying: -3.015≤F1 / F≤-2.895; -3.217≤F2 / F≤-3.018; 3.057≤F3 / F≤3.314; 3.317≤F4 / F≤3.610.

[0038] In the head-mounted display optical system provided in this embodiment, the curvature of the cylindrical cemented lens 2 in the horizontal direction is relatively gentle, and the surface compensation pressure is relatively small. Compensation can be performed on the outer or inner surface of the cylindrical cemented lens 2. Since the processing cost and difficulty of the first lens 21 are relatively low, asymmetric compensation is performed on the side of the first lens 21 near the exit pupil 1.

[0039] Understandably, by asymmetrically compensating the side of the first lens 21 near the exit pupil 1, asymmetric aberrations can be better corrected, field uniformity improved, the impact of surface shape changes reduced, and the wearing experience of the head-mounted display optical system improved.

[0040] Furthermore, in one embodiment, the refractive index of the first lens 21 is N1, the Abbe number of the first lens 21 is V1, the refractive index of the second lens 22 is N2, and the Abbe number of the second lens 22 is V2, satisfying: 1.012≤N1 / N2≤3.610; 0.486≤V1 / V2≤0.913.

[0041] It is understandable that by limiting the resolution and Abbe number of the first lens 21 and the second lens 22 respectively, the achromatic effect of the cylindrical cemented lens 2 can be improved, and the imaging effect of the head-mounted display optical system can be further improved.

[0042] Furthermore, in one embodiment, the center thickness of the head-mounted display optical system is D, the center thickness of the first lens 21 is D1, and the center thickness of the second lens 22 is D2. 2， It satisfies: 0 < D ≤ 12 mm, 0.165 ≤ D1 / D ≤ 0.197, 0.721 ≤ D2 / D ≤ 0.777.

[0043] It is understandable that by setting the center thickness range of the head-mounted display optical system, the first lens 21 and the second lens 22, the lens thickness of the first lens 21 and the second lens 22 can be effectively controlled, the thickness of the head-mounted display optical system can be reduced, thereby optimizing the internal space layout of the head-mounted display device and reducing the size and weight of the head-mounted display device.

[0044] For further details, please refer to... Figures 4 to 6 In a preferred embodiment, the head-mounted display optical system further includes a third lens 4, which is cemented to the first lens 21, and a reflective polarizing film 23 is mounted between the third lens 4 and the first lens 21.

[0045] Specifically, the first lens 21, the second lens 22, and the third lens 4 constitute a three-element cemented lens. The first lens 21 and the second lens 22 are still cemented cylindrically, with the cylindrical surface remaining curved in the horizontal direction and planar in the vertical direction. Preferably, the first lens 21, the second lens 22, and the third lens 4 are all aspherical plastic lenses. Similarly, the head-mounted display optical system provided in this preferred embodiment is designed based on the principle of a pancake folded optical path.

[0046] It is easy to understand that by adding a third lens 4, a three-element cemented lens is further constructed on the basis of the cylindrical cemented lens 2 formed by the first lens 21 and the second lens 22. This can effectively reduce the amount of air medium surface between the lenses, improve the imaging quality of the head-mounted display optical system, and at the same time, reduce the size and weight of the optical system.

[0047] Furthermore, in one embodiment, the effective focal length of the head-mounted display optical system is F5, the effective focal length of the first lens 21 in the horizontal direction is F6, the effective focal length of the first lens 21 in the vertical direction is F7, the effective focal length of the second lens 22 in the horizontal direction is F8, the effective focal length of the second lens 22 in the vertical direction is F9, and the effective focal length of the third lens 4 is F... 10； Satisfying: -5.978≤F6 / F5≤-5.587; -6.455≤F7 / F5≤-5.587; 3.910≤F8 / F5≤4.162; 4.165≤F9 / F5≤4.468; 4.885≤F 10 / F5≤5.023.

[0048] Specifically, the first lens 21 has positive optical power, the second lens 22 is a negative lens, and the third lens 4 is a positive lens. The cylindrical surfaces of both the first lens 21 and the second lens 22 are constructed using annular surfaces. The side of the first lens 21 closest to the third lens 4 and the side of the second lens 22 closest to the display 3 are both aspherical. The surface of the third lens 4 is also aspherical. It can be understood that the non-curved surface design of the third lens 4 can further correct advanced aberrations in the head-mounted display's optical system. By setting the effective focal length range of the first lens 21, the second lens 22, and the third lens 4, the overall length of the head-mounted display's optical system can be reduced to a certain extent, ensuring the imaging quality and stability of the optical system, and making it easier to control the field of view of the optical system.

[0049] Furthermore, in order to better adjust the imaging quality of the head-mounted display optical system, there are certain requirements for the range of parameters such as refractive index, Abbe number and thickness of the first lens 21, the second lens 22 and the third lens 4.

[0050] Specifically, in a preferred embodiment, the refractive indices of the first lens 21, the second lens 22, and the third lens 4 are N3, N4, and N5, respectively, and the Abbe numbers of the first lens 21, the second lens 22, and the third lens 4 are V3, V4, and V5, respectively, satisfying: 3.309 < N3 * N4 * N5 ≤ 3.647; 7.571 < V3 * V4 * V5 / 10000 ≤ 14.422.

[0051] It is understandable that the first lens 21, the second lens 22 and the third lens 4 have different refractive indices, which can adapt to light of different wavelengths, enabling the control and elimination of chromatic aberration. At the same time, they are more conducive to the correction of aberrations, and the relatively low curvature of the cylindrical surface is more conducive to the adhesion of optical films on the lens, further ensuring the imaging quality of the optical system.

[0052] The center thickness of the head-mounted display optical system is D3, the center thickness of the first lens 21 is D4, the center thickness of the second lens 22 is D5, and the center thickness of the third lens 4 is D6, satisfying: 0 < D3 ≤ 18 mm, 0.301 ≤ D4 / D3 ≤ 0.412, 0.111 ≤ D5 / D3 ≤ 0.139, and 0.434 ≤ D6 / D3 ≤ 0.502.

[0053] It is understandable that by setting the center thickness range of the first lens 21, the second lens 22 and the third lens 4, the lens thickness of each lens in the head-mounted display optical system can be effectively controlled, the thickness of the head-mounted display optical system can be reduced, and the internal space layout of the head-mounted display device can be optimized, thereby reducing the size and weight of the head-mounted display device.

[0054] In summary, by setting up a cylindrical cemented lens 2, and utilizing the principle of cylindrical cementation between the first lens 21 and the second lens 22 and the pancake folding optical path, this invention reduces the difficulty of lens cementation, improves the optical performance of the optical system, reduces the number of lenses, and reduces the size and weight of the optical system, thereby achieving lightweighting of the head-mounted display device and improving wearing comfort.

[0055] A second aspect of the present invention provides a head-mounted display device including the aforementioned head-mounted display optical system, which improves the optical performance of the optical system, reduces the size and weight of the optical system, thereby achieving a lightweight head-mounted display device and improving wearing comfort.

[0056] The above are merely specific embodiments of this application. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A head-mounted display optical system, characterized by, The head-mounted display optical system comprises an exit pupil portion, a cylindrical cemented lens, and a display; the cylindrical cemented lens comprises a first lens, a second lens, a reflective polarizing film, a quarter-wave plate, and a semi-transparent semi-reflective film; the first lens and the second lens are sequentially arranged between the exit pupil portion and the display; the reflective polarizing film is arranged on a side of the first lens close to the exit pupil portion; the first lens is cylindrically cemented to the second lens; the quarter-wave plate is arranged between the first lens and the second lens; and the semi-transparent semi-reflective film is arranged on a side of the second lens close to the display; a cover plate is arranged on a side of the display close to the second lens; and a polarizing plate is arranged between the display and the cover plate.

2. The head-mounted display optical system of claim 1, wherein, The cylindrical surface of the cylindrical cemented lens is curved in the horizontal direction, and the cylindrical surface of the cylindrical cemented lens is planar in the vertical direction.

3. The head-mounted display optical system of claim 1, wherein, The effective focal length of the head-mounted display optical system is F, the effective focal length of the first lens in the horizontal direction is F1, the effective focal length of the first lens in the vertical direction is F2, the effective focal length of the second lens in the horizontal direction is F3, and the effective focal length of the second lens in the vertical direction is F4, and the following conditions are met: -3.015≤F1 / F≤-2.895; -3.217≤F2 / F≤-3.018; 3.057≤F3 / F≤3.314; and 3.317≤F4 / F≤3.

610.

4. The head-mounted display optical system of claim 1, wherein, The refractive index of the first lens is N1, the Abbe number of the first lens is V1, the refractive index of the second lens is N2, and the Abbe number of the second lens is V2, and the following conditions are met: 1.012≤N1 / N2≤3.610; and 0.486≤V1 / V2≤0.

913.

5. The head-mounted optical system of claim 1, wherein, A center thickness of the head-mounted optical system is D, a center thickness of the first lens is D1, and a center thickness of the second lens is D2 2， 0 < D ≤ 12 mm, 0.165 ≤ D1 / D ≤ 0.197, and 0.721 ≤ D2 / D ≤ 0.777 are satisfied.

6. The head-mounted optical system of claim 1, wherein, The head-mounted display optical system further comprises a third lens, the third lens is cemented to the first lens, and the reflective polarizing film is arranged between the third lens and the first lens.

7. The head-mounted optical system of claim 6, wherein, An effective focal length of the head-mounted optical system is F5, an effective focal length of the first lens in a horizontal direction is F6, an effective focal length of the first lens in a vertical direction is F7, an effective focal length of the second lens in the horizontal direction is F8, an effective focal length of the second lens in the vertical direction is F9, and an effective focal length of the third lens is F 10； -5.978≤F6 / F5≤-5.587; -6.455≤F7 / F5≤-5.587; 3.910≤F8 / F5≤4.162; 4.165≤F9 / F5≤4.468; 4.885≤F 10 / F5≤5.

023.

8. The head-mounted optical system of claim 6, wherein, The refractive indices of the first lens, the second lens, and the third lens are N3, N4, and N5 respectively, and the Abbe numbers of the first lens, the second lens, and the third lens are V3, V4, and V5 respectively, and the following conditions are met: 3.309≤N3*N4*N5≤3.647; and 7.571≤V3*V4*V5 / 10000≤14.

422.

9. The head-mounted optical system of claim 1, wherein, The center thickness of the head-mounted display optical system is D3, the center thickness of the first lens is D4, the center thickness of the second lens is D5, and the center thickness of the third lens is D6, and the following conditions are met: 0≤D3≤18mm; 0.301≤D4 / D3≤0.412; 0.111≤D5 / D3≤0.139; and 0.434≤D6 / D3≤0.

502.

10. A head-mounted display device, comprising: The head-mounted display optical system comprises the head-mounted display optical system according to any one of the preceding claims 1 to 9.

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