Optical systems for miniaturized head-mounted displays

Abstract

The present invention provides an optical system for a miniaturized head-mounted display. After an optical module and in front of a display screen, at least one phase retardation element, a partially transmissive and partially reflective element, and a reflective polarizing element are arranged. After the light emitted from the display screen is incident, it undergoes multiple polarizations, reflections, and re-polarizations to obtain polarized light that can penetrate the last reflective polarizing element. After passing through this reflective polarizing element, it is incident on the optical module and then guided into the human eye. When there are N optical lenses in the optical module, #imgabs0# where V dj and n j are the Abbe number and refractive index of the optical lens respectively, and 1 ≤ j ≤ 3. In the present invention, all optical elements are on the same axis. Through multiple polarizations and reflections, the shortest distance between the display screen and the final optical module is obtained under the condition of an approximate optical path, achieving the purpose of miniaturizing the head-mounted display.

Description

Technical Field

[0001] The present invention relates to a head mounted display technology, and in particular to an optical system of a miniaturized head mounted display. Background Art

[0002] A head-mounted display is a device used to display images and colors. It is usually in the form of an eye mask or a helmet. The display screen is placed close to the user's eyes. The focal length is adjusted through the optical path to project the image to the eyes at a close distance, creating a virtual image magnification effect and increasing the sense of presence.

[0003] Figure 1 The figure shows a virtual reality head mounted display. The image projected by the display screen 10 enters the optical module 20 after passing through an optical path of an optical path d. The optical module 20 then guides the image into the user's human eye 22. Assuming that the optical path d is 40 mm, the length of the head mounted display, which is the optical path d plus the optical module, the eye relief and the housing, must be greater than 40 mm. It is somewhat bulky for the eye mask and helmet worn on the head. Therefore, it is an important issue to reduce the thickness of the head mounted display to facilitate the user to wear and use.

[0004] Therefore, the present invention proposes an optical system of a miniaturized head mounted display, which effectively solves the above-mentioned problems. The specific architecture and implementation methods thereof are described in detail below: Summary of the invention

[0005] The main purpose of the present invention is to provide an optical system for a miniaturized head-mounted display, which is a system in which optical elements such as a polarization element, a phase delay element, a partially reflective and partially penetrating element are arranged between the display screen and the optical module of the head-mounted display, and the phase delay and multiple reflections of light are used to achieve an optical path of approximate length, so as to shorten the distance between the display screen and the optical module, thereby miniaturizing the head-mounted display.

[0006] Another object of the present invention is to provide an optical system for a miniaturized head-mounted display, in which all optical elements are coaxially arranged and adjusted according to the polarization of the display screen, so as to increase the variability and flexibility of the optical system configuration while shortening the distance between the display screen and the optical module.

[0007] To achieve the above-mentioned purpose, the present invention provides an optical system of a miniaturized head-mounted display, comprising: a display screen, outputting images and emitting polarized light; a partially reflective and partially transmissive element, arranged corresponding to the display screen, causing the polarized light to partially reflect and partially penetrate the partially reflective and partially transmissive element; a second phase delay element, arranged corresponding to the partially reflective and partially transmissive element, performing phase delay on the polarized light partially penetrating the partially reflective and partially transmissive element to become polarized light of a second polarization angle; a reflective polarizing element, arranged corresponding to the second phase delay element, receiving the polarized light of the second polarization angle and performing total reflection, reflecting to the second phase delay element, the polarized light of the second polarization angle passing through the second phase delay element and the partially reflective and partially transmissive element, and then being reflected by the partially reflective and partially transmissive element back to the second phase delay element and the reflective polarizing element and penetrating; and an optical module, corresponding to the reflective polarizing element, the optical module comprising at least one optical lens, for receiving the polarized light penetrating the reflective polarizing element and directing the polarized light into at least one eye, wherein when the at least one optical lens in the optical module is N, Where V dj is the Abbe number of the optical lens, n j is the refractive index of the optical lens, 1≤j≤3

[0008] According to an embodiment of the present invention, the radius of curvature of the optical surface of the at least one optical lens of the optical module closest to the human eye is R eye ,

[0009] According to an embodiment of the present invention, the at least one optical lens is closest to the human eye. The first lens does not include a planar light-transmitting element and a film with a polarizing function. The curvature radius of the optical surface of the first lens facing the human eye is R 1 , the radius of curvature on the other side is R 2 , the maximum visible radius of the optical system is H,

[0010] According to an embodiment of the present invention, the optical surface of the at least one optical lens of the optical module that is closest to the human eye is a plane, a spherical surface, an aspherical surface, a Fresnel surface, a free-form surface, or a partially concave and partially convex surface.

[0011] According to an embodiment of the present invention, the optical module includes a linear polarizer disposed on a planar light-transmitting element or the optical lens.

[0012] According to an embodiment of the present invention, the linear polarizer is disposed on the last surface of the optical module, and the second phase retardation plate and the reflective polarizer are disposed on the linear polarizer.

[0013] According to an embodiment of the present invention, the second phase retarder and the reflective polarizer are arranged on the last surface of the optical lens in the optical module.

[0014] According to an embodiment of the present invention, the thickness of the optical module is TTL, 1≦TTL≦11.

[0015] According to an embodiment of the present invention, the focal length of the reflective surface of the partially reflective and partially transmissive element is fs, 122≦fs≦infinity, and F is the effective focal length of the optical system.

[0016] According to an embodiment of the present invention, when the at least one optical lens in the optical module satisfies When the at least one optical lens does not include a flat glass element and a polarizer.

[0017] According to an embodiment of the present invention, the reflective polarization element is a polarizer, and the second phase delay element is a phase delay plate.

[0018] According to an embodiment of the present invention, the reflective polarization element is an element with reflective polarization function provided in the optical module, or is a lens with reflective polarization function in the optical module, and the second phase delay element is a phase delay plate.

[0019] According to an embodiment of the present invention, the reflective polarization element is an element with a reflective polarization function provided in the optical module, or is a lens with a reflective polarization function in the optical module, and the second phase delay element is also provided in the optical module, and is an element with a phase delay function before the reflective polarization element, or is a lens with a phase delay function in the optical module.

[0020] According to an embodiment of the present invention, the polarized light sent out from the display screen and entering the partially reflective and partially transmissive element is circularly polarized light.

[0021] According to an embodiment of the present invention, the polarized light sent out by the display screen is linearly polarized light, and a first phase delay element is further provided between the display screen and the partially reflective and partially transmissive element to perform a first phase delay on the polarized light to become polarized light of a first polarization angle, and to convert the linear polarized light into circularly polarized light after passing through the first phase delay element.

[0022] According to an embodiment of the present invention, the reflective polarization element totally reflects the polarized light of the second polarization angle back to the second phase delay element, so that the polarized light of the second polarization angle penetrates the second phase delay element and becomes the polarized light of the third polarization angle. After the polarized light of the third polarization angle is partially reflected back to the second phase delay element by the partially reflecting and partially penetrating element, it penetrates the second phase delay element and becomes the polarized light of the fourth polarization angle. The polarized light of the fourth polarization angle penetrates the reflective polarization element.

[0023] As mentioned above, among the polarized light with the second polarization angle, the part that partially penetrates the second phase delay element is linearly polarized light, and the part that is reflected by the reflective polarization element and then penetrates the second phase delay element is circularly polarized light.

[0024] According to an embodiment of the present invention, the polarized light of the second polarization angle reflected by the reflective polarization element is linearly polarized light, and the polarized light of the fourth polarization angle passed through the reflective polarization element is linearly polarized light.

[0025] According to an embodiment of the present invention, the polarized light sent out by the display screen has no specific polarization state, and a linear polarizer and a first phase delay element are further provided between the display screen and the partially reflective and partially transmissive element. The linear polarizer is provided between the display screen and the first phase delay element. The polarized light provided by the display screen becomes linear polarized light after passing through the linear polarizer. The first phase delay element then performs a first phase delay on the linear polarized light to become polarized light of a first polarization angle, and converts the polarized light of the first polarization angle into circularly polarized light.

[0026] According to an embodiment of the present invention, the optical module is a plane, spherical, aspherical, Fresnel, free-form, or partially concave and partially convex lens, and is a combination of one or more lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The diagram is a schematic diagram of the optical path between the display screen of a head mounted display and the human eye in the prior art.

[0028] Figure 2A and Figure 2B FIG. 4 is a schematic diagram of an optical system of a miniaturized head mounted display according to an embodiment of the present invention.

[0029] Figure 3A FIG. 4 is a schematic diagram of another embodiment of an optical system of a miniaturized head mounted display according to the present invention.

[0030] Figure 3B and Figure 3C For a conventional head mounted display and the present invention Figure 3A Schematic diagram of the comparison of the optical systems of head-mounted displays.

[0031] Figure 4 FIG. 4 is a schematic diagram of another embodiment of an optical system of a miniaturized head mounted display according to the present invention.

[0032] Figure 5 FIG. 4 is a schematic diagram of another embodiment of an optical system of a miniaturized head mounted display according to the present invention.

[0033] Figures 6 to 12 FIG. 4 is a schematic diagram of another embodiment of an optical system of a miniaturized head mounted display according to the present invention.

[0034] Explanation of the reference numerals: 10 - display screen; 11 - linear polarizer; 12 - first phase delay element; 14 - partially reflective and partially transmissive element; 16 - second phase delay element; 18 - reflective polarization element; 19 - lens, first lens; 20 - optical module; 202 - plane light-transmitting element; 204 - linear polarizer; 205 - first lens; 206 - second lens; 208 - third lens; 22 - human eye. DETAILED DESCRIPTION

[0035] The present invention provides an optical system for a miniaturized head-mounted display, which is applied to the head-mounted display, in particular to a virtual reality system of the head-mounted display. Since the head-mounted display is worn on the user's head, if the head-mounted display is too large or too long, it is difficult to fix it on the user's head and will fall due to gravity. Therefore, the head-mounted display should be as small as possible. The purpose of the present invention is to use multiple lenses to reflect light multiple times, so as to shorten the distance between the optical module and the display screen under the condition of a similar optical path length, so as to achieve the purpose of miniaturizing the head-mounted display.

[0036] Please refer to Figure 2A and Figure 2B , which is a schematic diagram of an embodiment of the optical system of the miniaturized head mounted display of the present invention, including a display screen 10, a partially reflective and partially transmissive element 14, a second phase delay element 16, a reflective polarization element 18 and an optical module 20. First, please refer to Figure 2AIn this embodiment, the display screen 10 outputs an image and emits polarized light, such as the polarized light 1 shown in the figure; the partially reflective and partially transmissive element 14 is arranged corresponding to the display screen 10, and reflects part of the incident polarized light 1 back to the display screen 10, and the rest penetrates the partially reflective and partially transmissive element 14. In a preferred embodiment, the partially reflective and partially transmissive element 14 is half reflective and half transmissive; in addition, in this embodiment, the second phase delay element 16 is an independent phase delay plate, and the reflective polarization element 18 is an independent polarization plate. The second phase delay element 16 is arranged corresponding to the partially reflective and partially transmissive element 14, and the polarized light 1 penetrating the partially reflective and partially transmissive element 14 is phase delayed for a second time to become polarized light 2 of a second polarization angle; the reflective polarization element 18 is arranged corresponding to the second phase delay element 16, and the polarized light 2 is totally reflected back to the second phase delay element 16, and after the polarized light 2 penetrates the second phase delay element 16, it is polarized once again to become polarized light 3 of a third polarization angle.

[0037] Please refer to Figure 2B After the polarized light 3 of the third polarization angle penetrates the second phase delay element 16 and reaches the partially reflecting and partially penetrating element 14, it is partially reflected back to the second phase delay element 16 by the partially reflecting and partially penetrating element 14 (the partially penetrating part is energy loss), and is polarized after penetrating the second phase delay element 16 to become the polarized light 4 of the fourth polarization angle. At this time, the fourth polarization angle of the polarized light 4 meets the penetration condition of the reflective polarization element 18, so the polarized light 4 can penetrate the reflective polarization element 18 and enter the corresponding optical module 20, and the optical module 20 guides the polarized light 4 into at least one human eye 22.

[0038] In a first embodiment, the light emitted by the display screen 10 is circularly polarized light with a polarization of 45 degrees, so the first polarization angle is 45 degrees (i.e., polarized light 1 is a 45-degree polarized light), and the second phase delay element 16 is a 45-degree polarization element, the second polarization angle is 90 degrees (i.e., polarized light 2 is a 90-degree polarized light), the third polarization angle is 135 degrees (i.e., polarized light 3 is a 135-degree polarized light), and the fourth polarization angle is 180 degrees (i.e., polarized light 4 is a 180-degree polarized light). In this embodiment, the reflective polarization element 18 only provides 180-degree polarized light to pass through, so polarized light 4 can pass through the reflective polarization element 18.

[0039] In a second embodiment, the display screen 10 has different polarization states, and its first polarization angle is 135 degrees (i.e., polarized light 1 is polarized light of 135 degrees), but it also emits circularly polarized light, and the second phase delay element 16 is also a 45-degree polarization element, the second polarization angle is 0 or 180 degrees (i.e., polarized light 2 is polarized light of 0 or 180 degrees), the third polarization angle is 45 degrees (i.e., polarized light 3 is polarized light of 45 degrees), and the fourth polarization angle is 90 degrees (i.e., polarized light 4 is polarized light of 90 degrees). In this embodiment, the reflective polarization element 18 only allows 90-degree polarized light to pass through, so polarized light 4 can pass through the reflective polarization element 18.

[0040] exist Figure 2A , Figure 2B In the embodiment, the polarized light 1 emitted by the display screen 10 is circularly polarized light; the polarized light 2 partially penetrating the second phase delay element 16 is linearly polarized light, and the polarized light 2 reflected by the reflective polarization element 18 is also linearly polarized light, but the polarized light 3 becomes circularly polarized light after passing through the second phase delay element 16. The polarized light 3 is originally circularly polarized light, but after being partially penetrating the second phase delay element 16 and reflecting, the polarized light 4 becomes linearly polarized light after passing through the second phase delay element 16 again, until the polarized light 4 penetrating the reflective polarization element 18 is still linearly polarized light.

[0041] In the present invention, the focal length of the reflective surface of the partially reflective and partially transmissive element 14 is fs, 122≦fs≦infinity, and F is the effective focal length of the optical system.

[0042] In the present invention, the optical module 20 is a plane, spherical, aspherical, Fresnel, free-form, or partially concave and partially convex lens, and is a combination of one or more lenses.

[0043] Figure 3A FIG. 1 is a schematic diagram of another embodiment of the optical system of the miniaturized head mounted display of the present invention. If the display screen 10 emits linear polarized light instead of circularly polarized light, then Figure 3AAs shown, a first phase delay element 12 is added behind the display screen 10 to convert the polarized light emitted by the display screen 10 into circularly polarized light, and perform the first phase delay to become polarized light 1 of the first polarization angle. After the polarized light 1 passes through the partially reflective and partially penetrating element 14, part of it is reflected back to the first phase delay element 12, and the rest penetrates the partially reflective and partially penetrating element 14; the polarized light 1 that partially penetrates the partially reflective and partially penetrating element 14 then passes through the second phase delay element 16, and becomes polarized light 2 of the second polarization angle after the second phase delay; the polarized light 2 is totally reflected back to the second phase delay element 16 by the reflective polarization element 18, and is polarized again into polarized light 3 of the third polarization angle after penetrating the second phase delay element 16. After the polarized light 3 penetrates the second phase delay element 16 and reaches the partially reflective and partially penetrating element 14, it is partially reflected back to the second phase delay element 16 by the partially reflective and partially penetrating element 14 (the partially penetrated portion is energy loss), and is polarized after penetrating the second phase delay element 16 to become the polarized light 4 with a fourth polarization angle. At this time, the fourth polarization angle of the polarized light 4 meets the penetration condition of the reflective polarization element 18, so the polarized light 4 can penetrate the reflective polarization element 18 and enter the corresponding optical module 20, and the optical module 20 guides the polarized light 4 into at least one human eye 22.

[0044] In a third embodiment, the polarized light emitted by the display screen 10 is 0-degree linear polarized light, the first phase delay element 12 is a 45-degree polarizing element, so the first polarization angle is 45 degrees (i.e., polarized light 1 is 45-degree polarized light), and the second phase delay element 16 is a 45-degree polarizing element, the second polarization angle is 90 degrees (i.e., polarized light 2 is 90-degree polarized light), the third polarization angle is 135 degrees (i.e., polarized light 3 is 135-degree polarized light), and the fourth polarization angle is 180 degrees (i.e., polarized light 4 is 180-degree polarized light). In this embodiment, the reflective polarizing element 18 only provides 180-degree polarized light to pass through, so polarized light 4 can pass through the reflective polarizing element 18.

[0045] In a fourth embodiment, the display screen emits polarized light of 90 degrees linear polarized light, and the first phase delay element 12 is a 45-degree polarizing element, so the first polarization angle is 135 degrees (i.e., polarized light 1 is 135 degrees polarized light), the second phase delay element 16 is also a 45-degree polarizing element, the second polarization angle is 0 or 180 degrees (i.e., polarized light 2 is 0 or 180 degrees polarized light), the third polarization angle is 45 degrees (i.e., polarized light 3 is 45 degrees polarized light), and the fourth polarization angle is 90 degrees (i.e., polarized light 4 is 90 degrees polarized light). In this embodiment, the reflective polarizing element 18 only provides 90 degrees polarized light to pass through, so polarized light 4 can pass through the reflective polarizing element 18.

[0046] Figure 3B and Figure 3C for Figure 1 Conventional head mounted display and the present invention Figure 3A Schematic diagram of comparison of the optical system of the head-mounted display. The present invention can set the first phase delay element 12 and the partially reflective and partially penetrating element 14 as a group, and the second phase delay element 16 and the reflective polarization element 18 as a group. For example, the second phase delay element 16 and the reflective polarization element 18 can be the same lens. For example, an element with a reflective polarization function is set on the side of the second phase delay plate 16 close to the optical module 20 as the reflective polarization element 18, or special materials are used to achieve the same lens with phase delay and reflective polarization functions. Similarly, the first phase delay element 12 and the partially reflective and partially penetrating element 14 can also be made on the same lens through material selection. It is well known that the thickness of the lens will affect the refractive index and the optical path. When the lens is thicker, the refractive index is higher, so the difference in the optical path is also higher, but the error is very small and still within the allowable range, so Figure 3B and Figure 3C It can be said that the optical path d (the total length of the dotted line in the figure) is almost the same, but the optical system of the present invention has a shorter back focal distance, which can shorten the back focal distance of the traditional head-mounted display to 0.3 to 0.7 times, and can achieve the same clear image effect as the traditional head-mounted display.

[0047] Figure 4 FIG. 1 is a schematic diagram of another embodiment of the optical system of the miniaturized head mounted display of the present invention. If the display screen 10 does not have a specific polarization state, then Figure 4As shown, a linear polarizer 11 is added after the display screen 10 and before the first phase delay element 12 to convert the polarized light emitted by the display screen 10 into linear polarized light. After passing through the first phase delay element 12, the linear polarized light becomes polarized light 1 of the first polarization angle, and the polarized light 1 becomes circular polarized light. After passing through the partially reflective and partially transmissive element 14, the polarized light 1 is partially reflected back to the first phase delay element 12, and the rest passes through the partially reflective and partially transmissive element 14; the polarized light 1 that partially passes through the partially reflective and partially transmissive element 14 then passes through the second phase delay element 16, and becomes polarized light 2 of the second polarization angle after a second phase delay; the polarized light 2 is totally reflected back to the second phase delay element 16 by the reflective polarization element 18, and after passing through the second phase delay element 16, it is polarized again into polarized light 3 of the third polarization angle. After the polarized light 3 penetrates the second phase delay element 16 and reaches the partially reflective and partially penetrating element 14, it is partially reflected back to the second phase delay element 16 by the partially reflective and partially penetrating element 14 (the partially penetrated portion is energy loss), and is polarized after penetrating the second phase delay element 16 to become the polarized light 4 with a fourth polarization angle. At this time, the fourth polarization angle of the polarized light 4 meets the penetration condition of the reflective polarization element 18, so the polarized light 4 can penetrate the reflective polarization element 18 and enter the corresponding optical module 20, and the optical module 20 guides the polarized light 4 into at least one human eye 22.

[0048] In a fifth embodiment, if the first phase delay element 12 and the second phase delay element 16 are 45-degree polarization elements, the partially reflective and partially transmissive element 14 is half reflective and half transmissive, and the reflective polarization element 18 only provides 180-degree polarized light transmission, then when the display screen 10 does not have a specific polarization state, the light first passes through the linear polarizer 11 to become a linear polarized light, and then passes through the first phase delay element 12 to increase the phase delay of 45 degrees, so that the light passing through the first phase delay element 12 is 45-degree polarized light 1, and then passes through the partially transmissive and partially reflective element 14 to make the light 45 degrees polarized. The 5-degree polarized light 1 partially penetrates, and after passing through the second phase delay element 16, its polarization is converted into the polarized light 2 with a phase delay of 90 degrees, and completes total reflection on the reflective polarization element 18, so that the reflected light passes through the second phase delay element 16 again, and the phase of the polarized light 3 is adjusted from 90 degrees to 135 degrees, and then passes through the partially penetrating and partially reflecting element 14 to be reflected back to the second phase delay element 16. At this time, the phase delay of the polarized light 3 is adjusted from 135 degrees to the original polarization state of the polarized light 4 of 180 degrees, which can be incident on the optical module 20.

[0049] In a sixth embodiment, the display screen 10 also has no specific polarization state, but the linear polarizer 11 emits 90-degree linear polarized light, the first phase delay element 12 is a 45-degree polarizing element, so the first polarization angle is 135 degrees (i.e., polarized light 1 is 135-degree polarized light), and the second phase delay element 16 is also a 45-degree polarizing element, the second polarization angle is 0 or 180 degrees (i.e., polarized light 2 is 0 or 180-degree polarized light), the third polarization angle is 45 degrees (i.e., polarized light 3 is 45-degree polarized light), and the fourth polarization angle is 90 degrees (i.e., polarized light 4 is 90-degree polarized light). In this embodiment, the reflective polarizing element 18 only provides 90-degree polarized light to pass through, so polarized light 4 can pass through the reflective polarizing element 18.

[0050] In the present invention, all elements are on the same axis, and according to the polarization state of the display screen of the head-mounted display, the Figure 3A and Figure 4 The display screen 10 and the linear polarizer 11 are adjusted by adding or subtracting. In short, if the display screen 10 emits circularly polarized light, there is no need to set the linear polarizer 11 and the first phase delay element 12; if the display screen 10 emits linearly polarized light, the first phase delay element 12 needs to be set; if the display screen 10 emits polarized light without a specific polarization state, the linear polarizer 11 and the first phase delay element 12 need to be set at the same time.

[0051] The present invention uses the principle that similar optical paths can achieve the same image to shorten the length of the head mounted display. For example, Figure 3A The optical path from the display screen 10 to the optical module 20 undergoes multiple reflections. Figure 3A In the embodiment of the present invention, the optical path length after the sum of the lengths of each reflection from the display screen 10 to the optical module 20 is d, and Figure 1 In the prior art, the optical path d from the display screen 10 to the optical module 20 is almost the same, but due to Figure 3A In the embodiment, the optical path from the display screen 10 to the optical module 20 is summed up after multiple reflections, so the actual length from the display screen 10 to the optical module 20 is much shorter than Figure 1 The length from the display screen 10 to the optical module 20 is reduced, thereby achieving the purpose of shortening the length of the head-mounted display.

[0052] In addition, the optical module 20 may further include at least one optical lens. For example, the reflective polarization element 18, or the reflective polarization element 18 and the second phase delay element 16 are disposed in the optical module. If only the reflective polarization element is disposed in the optical module, it may be an element with a reflective polarization function. If both are disposed in the optical module, then Figure 5As shown in FIG. 1 , the reflective polarizing element 18 is an element with a reflective polarizing function, and the second phase delay element 16 is an element with a phase delay function and is located before the reflective polarizing element 18. In this way, the back focus distance can be shortened. In summary, the optical surface (such as the optical surface closest to the human eye 22) of at least one optical lens in the optical module 20 Figure 5 The radius of curvature of the lens 19 (the side close to the human eye 22) is R eye , In addition, the optical surface of the lens 19 closest to the human eye 22 is a plane, a spherical surface, an aspherical surface, a Fresnel surface, a free-form surface, or a partially concave and partially convex surface.

[0053] In one embodiment of the present invention, the optical module closest to the human eye 22 is a first lens (eg Figure 5 The first lens 19 does not include a planar light-transmitting element and a film with a polarizing function, and the curvature radius of the optical surface of the first lens 19 facing the human eye is R 1 (equal to R in the previous paragraph eye ), the radius of curvature of the other side is R 2 , the maximum visible radius of the optical system of the present invention is H,

[0054] In addition, in another embodiment of the present invention, the optical module 20 includes a linear polarizer, which is disposed on a planar light-transmitting element or an optical lens. Figure 6 , assuming that the optical module 20 includes a planar light-transmitting element 202, and the linear polarizer 204 is disposed on the planar light-transmitting element 202 in the form of a lens or a coating. In addition, the linear polarizer can be further disposed on the last side of the optical module 20, such as Figure 6 The mid-line polarizer 204 is disposed on the last lens, that is, on the left side of the planar light-transmitting element 202 , and is the last side of the optical module 20 .

[0055] In another embodiment, the second phase retarder 16 and the reflective polarizer 18 are disposed on the last surface of the last optical lens of the optical module 20, or on the last linear polarizer 204 of the optical module 20. Figure 6 For example, the positions of the second phase retarder 16 and the reflective polarizer 18 are changed to be on the linear polarizer 204 .

[0056] Figure 7 In another embodiment of the present invention, in one embodiment of the present invention, when the number of optical lenses in the optical module 20 is N and the condition is satisfied Where V dj is the Abbe number of the optical lens, n j is the refractive index of the optical lens. At this time, the optical lens in the optical module 20 does not include flat glass and polarizer. Figure 7For example, the optical lens in the optical module 20 includes three lenses, which are a first lens 205, a second lens 206 and a third lens 208 in order from the human eye 22 to the display screen 10, and their refractive indices are n 1 、n 2 、n 3 , and the Abbe numbers are V d1 、V d2 、V d3 The first, second and third lenses 205, 206 and 208 do not include a planar light-transmitting element and a polarizing film, and For example, Figure 7 Although the first lens 205 is a plane, it can be a plane lens or a linear polarizer, rather than a plane light-transmitting element or a polarizer.

[0057] Figures 8 to 12 Schematic diagram of another embodiment of the optical system of the miniaturized head mounted display of the present invention. Figure 8 The embodiment includes a display screen 10, a partially reflective and partially transmissive element 14, a second phase delay element 16, a reflective polarization element 18, a planar light-transmitting element 202, a linear polarizer 204 and a first lens 205 in sequence. The first lens 205 in this figure is an optical module, and is a Fresnel lens. Fig. 9 The embodiment includes a display screen 10, a partially reflective and partially transmissive element 14, a second phase delay element 16, a reflective polarization element 18, a plane light-transmitting element 202, a first lens 205, a plane light-transmitting element 202 and a linear polarizer 204 in sequence. The first lens 205, the plane light-transmitting element 202 and the linear polarizer 204 in this figure are an optical module, and the first lens 205 is a Fresnel lens. Fig.10 The embodiment includes a display screen 10, a partially reflective and partially transmissive element 14, a second phase delay element 16, a reflective polarization element 18, a planar light-transmitting element 202, a second lens 206, a linear polarizer 204 and a first lens 205 in sequence. In this figure, the reflective polarization element 18 to the first lens 205 are all included in an optical module, and the first lens 205 is a spherical or aspherical lens, and the second lens 206 is a Fresnel lens. Fig.11 The embodiment includes a display screen 10, a partially reflective and partially transmissive element 14, a second phase delay element 16, a reflective polarizing element 18, a plane light-transmitting element 202, a second lens 206, a first lens 205, a linear polarizing plate 204 and a plane light-transmitting element 202 in sequence. In this figure, the plane light-transmitting element 202 from the reflective polarizing element 18 to the human eye is all included in the optical module, and the first lens 205 is a spherical or aspherical lens, and the second lens 206 is a Fresnel lens. Fig.12The embodiment of the present invention sequentially comprises a display screen 10, a partially reflective and partially transmissive element 14, a second phase delay element 16, a reflective polarizing element 18, a planar light-transmitting element 202, a linear polarizing plate 204, a second lens 206, and a first lens 205. The optical module of this embodiment comprises the second lens 206 and the first lens 205, and the first lens 205 is a spherical or aspherical lens, and the second lens 206 is a spherical or aspherical lens. Fig.12 It can be seen from the embodiments that the optical module 20 of the present invention may include one or more optical lenses, and may be a combination of various lenses such as plane, plane, concave, biconvex, etc. If the first lens 205 closest to the human eye in the optical module 20 is a plane lens, a linear polarizer 204 may be disposed thereon to further remove stray light.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Therefore, all equivalent changes or modifications based on the features and spirit described in the scope of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical system for a miniaturized head-mounted display, characterized in that: include: a display screen that outputs images and emits polarized light; A partially reflective and partially transmissive element is disposed corresponding to the display screen so that the polarized light is partially reflected and partially penetrated by the partially reflective and partially transmissive element; The partially reflective and partially transmissive element reflects part of the incident polarized light back to the display screen; a second phase delay element, arranged corresponding to the partially reflective and partially transmissive element, receiving the polarized light partially penetrating the partially reflective and partially transmissive element, and performing phase delay to convert the polarized light into polarized light of a second polarization angle; a reflective polarizing element, arranged corresponding to the second phase delay element, receiving the polarized light of the second polarization angle and performing total reflection, and reflecting the polarized light to the second phase delay element; after the polarized light of the second polarization angle passes through the second phase delay element and the partially reflective and partially transmissive element, it is reflected by the partially reflective and partially transmissive element back to the second phase delay element and the reflective polarizing element and penetrates; and a group of optical modules, arranged corresponding to the reflective polarization element, wherein the optical module includes at least one optical lens to receive polarized light penetrating the reflective polarization element and guide the polarized light into at least one eye, wherein when the number of the at least one optical lens in the optical module is N, Wherein Vdj is the Abbe number of the at least one optical lens, nj is the refractive index of the at least one optical lens, and 1≤j≤3; Among them, j=2, N=3; The first lens is the closest to the human eye in the at least one optical lens. The first lens does not include a planar light-transmitting element and a film with a polarizing function. The curvature radius of the optical surface of the first lens facing the human eye is R1, and the curvature radius of the other side is R2. The maximum visible radius of the optical system is H. ; The curvature radius of the optical surface of the at least one optical lens of the optical module closest to the human eye is Reye, .

2. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The optical surface of the at least one optical lens of the optical module that is closest to the human eye is a plane, a spherical surface, an aspherical surface, or a free-form surface.

3. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The optical module includes a linear polarizer which is arranged on a planar light-transmitting element or the optical lens.

4. The optical system of the miniaturized head mounted display according to claim 3, characterized in that: The linear polarizer is arranged on the last side of the optical module, and the second phase delay element and the reflective polarization element are arranged on the linear polarizer.

5. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The second phase delay element and the reflective polarization element are arranged on the last surface of the optical lens in the optical module.

6. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The thickness of this optical module is TTL, 1mm≦TTL≦11mm.

7. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The at least one optical lens in the optical module satisfies When the at least one optical lens does not include flat glass and polarizing film.

8. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The reflective polarization element is a polarizer, and the second phase delay element is a phase delay plate.

9. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The reflective polarization element is an element provided in the optical module and has a reflective polarization function, and the second phase delay element is a phase delay plate.

10. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The reflective polarization element is an element provided in the optical module and has a reflective polarization function, and the second phase delay element is also provided in the optical module and is an element before the reflective polarization element and has a phase delay function.

11. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The polarized light sent out from the display screen and entering the partially reflective and partially transmissive element is circularly polarized light.

12. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The polarized light sent out by the display screen is linearly polarized light. A first phase delay element is further provided between the display screen and the partially reflective and partially transparent element to perform a first phase delay on the polarized light to become polarized light of a first polarization angle, and to convert the linearly polarized light into circularly polarized light after passing through the first phase delay element.

13. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: Among the polarized light of the second polarization angle, part of the polarized light that penetrates the second phase delay element is linearly polarized light, and part of the polarized light that is reflected by the reflective polarization element and then penetrates the second phase delay element is circularly polarized light.

14. The optical system of the miniaturized head mounted display according to claim 1, characterized in that: The reflective polarization element totally reflects the polarized light of the second polarization angle back to the second phase delay element, so that the polarized light of the second polarization angle penetrates the second phase delay element and becomes the polarized light of the third polarization angle. After the polarized light of the third polarization angle is partially reflected back to the second phase delay element by the partially reflecting and partially penetrating element, it penetrates the second phase delay element and becomes the polarized light of the fourth polarization angle. The polarized light of the fourth polarization angle penetrates the reflective polarization element, wherein the polarized light of the second polarization angle reflected by the reflective polarization element is linear polarized light, and the polarized light of the fourth polarization angle penetrated by the reflective polarization element is linear polarized light.

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