TWI711839B - Miniaturized short-distance optical system - Google Patents

Abstract

The present invention provides a miniaturized short-distance optical system, which sequentially includes a display screen, a reflective polarizing element, a first phase retarder, a part of the penetrating part of the reflective element, at least one optical element, and any of the above elements One lens on the side. The optical element can be a circular polarizer or a combination of a second phase retarder and a linear polarizer. After the display screen outputs the image and emits light, the light is reflected twice between the reflective polarizing element and the partially penetrating and partially reflective element, and the light passes through the first phase retarder three times. After the light passes through the third phase retardation, it passes through the third time. The phase-delayed light penetrates the part of the reflective element, and undergoes a fourth phase delay through the optical element. Finally, the phase-delayed light is guided into at least one eye through a lens, and only a single lens allows the present invention The overall thickness of the optical system is smaller, achieving the purpose of miniaturization.

Description

Miniaturized short-distance optical system

The present invention relates to an optical system, in particular to a miniaturized short-distance optical system that can be applied to a head-mounted display.

Head-mounted display (Head-mounted display) is a device used to display images and colors, usually in the form of an eye mask or a helmet. The display is placed close to the user's eyes, and the focus is adjusted through the optical path to project the eyes at close range The screen produces the effect of virtual reality and increases the wearer’s sense of presence.

Figure 1 shows a schematic diagram of the optical system of a head-mounted display in virtual reality. The display screen 10 projects an image, which passes through a light path with an optical path of d and then enters the optical module 23. The optical module 23 is a single lens or The combination of multiple lenses is used to guide the image into the user’s eyes 24, assuming that the optical path d is 40mm, and the length of the head-mounted display is the optical path d plus the thickness of the optical module, eye distance, and housing Etc., the sum of which is slightly cumbersome for eye masks and helmets worn on the head, and will cause a burden on the bridge of the nose, top of the head, and neck of the user and cannot be worn for a long time. Therefore, the current technology department is committed to reducing the length of the optical system It is shortened to reduce the thickness of the head mounted display, which is convenient for users to wear and use.

Therefore, the present invention proposes a miniaturized short-distance optical system, which can not only shorten the distance of the optical system, but also expand the field of view, effectively solving the above-mentioned problems. The specific structure and implementation methods will be detailed later.

The main purpose of the present invention is to provide a miniaturized short-distance optical system, in which optical elements such as reflective polarizing elements, phase retarders, partially penetrating and partially reflective elements are arranged between the front of the display screen and the optical module, and the phase of light is utilized. The delay and multiple reflections reach approximately or the same length of the optical path, thereby shortening the distance between the display screen and the optical module, and finally can be used to miniaturize the head-mounted display.

Another object of the present invention is to provide a miniaturized short-distance optical system, which is in any one of the reflective polarizing element, the first phase retarder, the partially penetrating partially reflective element, the second phase retarder, and the linear polarizer A single lens is set on either side of the lens, which can be miniaturized before adjusting the focus.

Another object of the present invention is to provide a miniaturized short-distance optical system, which can be applied to wide-angle lenses or wide-angle eyepieces on head-mounted displays, game consoles, etc., using only a single lens for focal length adjustment, which can maximize the thickness of the device Shorten, achieve short distance, large field of view, good aberration correction and other advantages.

In order to achieve the above objective, the present invention provides a miniaturized short-distance optical system, including: a display screen, which outputs images and emits polarized or unpolarized light; and a reflective polarizing element is set corresponding to the display screen so that the light partially penetrates Transparent and partially reflective; a first phase retarder is set corresponding to the reflective polarizing element, receives the light partially penetrating the reflective polarizing element, and performs the first phase retardation; part penetrating the partially reflective element, corresponding The first phase retarder is arranged so that part of the light that has undergone the first phase retardation penetrates the part of the reflective element, and part is reflected back to the first phase retarder for second and third phase retardation; An optical element is provided corresponding to the partially penetrating partially reflective element, receiving the light partially penetrating the partially penetrating partially reflective element and passing the second and third phase delays, and performing the fourth phase delay, and then let The light that has passed the fourth phase retardation passes but the light that has only passed the second phase retardation cannot pass; and a lens provided on the reflective polarizing element, the first phase retarder, the partially penetrating partially reflective element, and the optical Either side of any element in the element to adjust the focus and lead the image into the eyes of at least one person.

According to an embodiment of the present invention, between the display screen and the lens and between the lens and the human eye may further include one or more pieces of flat glass.

According to an embodiment of the present invention, the optical element includes: a second phase retarder disposed corresponding to the partially penetrating partially reflective element, the receiving portion penetrating the partially penetrating partially reflective element and passing through the second and third phases The light is retarded, and the fourth phase retardation is performed; and a linear polarizer is set corresponding to the second phase retarder. The linear polarizer is used to prevent the light that has only undergone two phase delays from passing through, and to allow the The light with four phase delay passes through.

According to an embodiment of the present invention, the optical element is a circular polarizer.

According to an embodiment of the present invention, the partially penetrating partially reflective element and the light reflected back to the first phase retarder passes through the second phase retardation of the first phase retarder, and then reaches the reflection through the first phase retarder. Type polarizing element, and complete reflection on the reflective polarizing element, so that the light is reflected back to the first phase retarder and undergoes a third phase retardation, and then the light passes through the first phase retarder and the partial penetration The partially reflective element reaches the second phase retarder, and the lens can be arranged on either side of the second phase retarder and the linear polarizer.

According to an embodiment of the present invention, the first, second, third, and fourth phase retardation are all increased by an odd multiple of 1/4 wavelength, so that the light reaching the human eye is retarded by an integer multiple of a wavelength. .

According to an embodiment of the present invention, when the light emitted from the display screen and enters the reflective polarizing element is polarized light, it can be linearly polarized light, circularly polarized light or other polarization states, and the display screen and the reflective polarized light According to the polarization of the display, at least one linear polarizer, circular polarizer or phase retarder can be added between the components to adjust the polarization state of the display. The new material can be thin film materials or optical coatings. The form of cloth, coating or bonding is arranged on the display screen or the reflective polarizing element. The linearly polarized light can be converted into left circularly polarized light or right circularly polarized light after passing through the first phase retarder.

，且

，且

。 According to an embodiment of the present invention, the visible radius of the display screen is H, the total length of the optical system is TTL, the distance from the eye to the center of the closest element surface of the optical system is E, and the half-field angle of the optical system is 𝜔, then

And

And

.

。 According to an embodiment of the present invention, the effective focal length of the optical system is F, the radius of curvature of the side of the lens close to the eye is R ₁ , and the radius of curvature of the side close to the display screen is R ₂ ,

.

The present invention provides a miniaturized short-distance optical system, which is applied to a head-mounted display, especially a virtual reality system of a head-mounted display. Since it is worn on the user's head, it is difficult to fix it in use if the volume is too large and too long. The head of the user will fall under the influence of gravity, which will also burden the head and neck of the user. Therefore, the size of the head mounted display is as small as possible, especially the length must be shortened. The purpose of the present invention is to use Multiple optical elements reflect light multiple times, and only a single lens is arranged between these optical elements to adjust the focal length, so that the overall optical system is shortened under the same length of optical path, so as to achieve the purpose of miniaturizing the head-mounted display.

Please also refer to Figures 2 and 3, which are respectively a schematic diagram and an exploded view of an embodiment of the miniaturized short-distance optical system of the present invention. In the miniaturized short-distance optical system of the present invention, a display screen 10 and at least A human eye 24 includes a reflective polarizing element 12, a first phase retarder 14, a partly penetrating partially reflective element 16, a second phase retarder 18, a linear polarizer 20, and a lens 22 in sequence. Among them, The display screen 10 outputs images and emits light. The light is polarized or unpolarized. When the light is polarized, the polarized light can be linearly polarized, circularly polarized or other polarization states. In this embodiment , The light is linearly polarized light. Furthermore, the polarization direction of the linearly polarized light in this embodiment is perpendicular to the optical path; the reflective polarizing element 12 is set corresponding to the display screen 10, and receives the polarized light emitted by the display screen 10, and Partially penetrate and partially reflect the polarized light, especially the reflective polarizing element 12 used in the present invention includes two polarization directions perpendicular to and parallel to the optical path, allowing vertical polarized light to penetrate and horizontally polarized light to reflect; The phase retarder 14 is set corresponding to the reflective polarizing element 12 to receive the polarized light partially penetrated by the reflective polarizing element 12, and perform the first, second and third phase retardation, of which the first and The polarized light of the third phase retardation is in the direction of the human eye 24, and the polarized light of the second phase retardation is in the direction of the display screen 10; the partially penetrating partially reflective element 16 is set corresponding to the first phase retarder 14 , Receives the light passing through the first phase retarder 14 and partially reflects and partially penetrates the light passing through; the second phase retarder 18 is set corresponding to the partially penetrating partially reflective element 16, and the receiving portion penetrates the partially penetrating partially reflective element The light from the element 16 is retarded for the fourth time; the linear polarizer 20 is set corresponding to the second retarder 18, and the linear polarizer 20 is used to prevent the polarized light that has only undergone two phase retardation from passing through and only let it pass through four The polarized light with the sub-phase retardation passes through, and the lens 22 is arranged on any side of any element in the above-mentioned optical system to guide the image into the human eye 24.

The single lens 22 provided in the present invention can be a convex lens. As shown in Figure 3, the lens 22 can be provided on the reflective polarizing element 12, the first phase retarder 14, the partially penetrating partially reflective element 16, the second Either side of the two-phase retarder 18 and the linear polarizer 20 is used to adjust the focal length. No matter it is placed between any two optical elements mentioned above, the optical system can be shortened eventually. In the embodiment in Figure 2, , The lens 22 is arranged on the left side of the linear polarizer 20, close to the human eye 24.

In particular, in the present invention, the fast and slow axis of the first retarder 14 and the transmission axis of the reflective polarizer 12 are angled at 45 degrees, which can increase the phase retardation of 1/4 wavelength.

In addition, the lens 22 in the present invention can be an aspheric lens, a Fresnel lens, or a combination of multiple lenses.

Please refer to Figures 4A to 4C for the specific steps of the present invention. First, in Figure 4A, the display screen 10 outputs an image and emits polarized light to the reflective polarizing element 12. The reflective polarizing element 12 makes the polarized light Part of the polarized light that penetrates to the first phase retarder 14 and part is reflected back to the display screen 10, and the partially penetrated polarized light that penetrates the reflective polarizer 12 passes through the first phase retarder 14, and undergoes the first phase retardation , And then reach the partially penetrating partially reflective element 16; then please refer to Figure 4B, the polarized light after the first phase retardation partially penetrates at the partially penetrating partially reflective element 16, and part is reflected back to the first phase retarder 14 Perform a second phase retardation, where the polarized light partially penetrating the partially reflective element 16 is energy loss, and the polarized light that has passed the first phase retardation penetrates the first phase retarder 14 and then reaches the reflective polarizer 12; Please refer to Figure 4C again. The reflective polarizing element 12 reflects the polarized light that has undergone the second phase retardation, and reflects it back to the first phase retarder 14 for the third phase retardation, and then passes through the partially penetrating and partially reflective element. 16. The partially penetrated polarized light (after the third phase retardation) reaches the second phase retardation plate 18 and undergoes the fourth phase retardation; then, the polarized light after the fourth phase retardation penetrates the second phase retardation The film 18 is screened by the linear polarizer 20 so that only the polarized light that has undergone four phase retardations passes through the linear polarizer 20 and is guided by the lens 22 into at least one human eye 24.

Since the first phase retarder 14 and the second phase retarder 18 in the present invention are both odd multiples of the phase retardation of 1/4 wavelength, the retardation is an integer multiple of 1 wavelength after four phase retardations.

The linearly polarized light passes through the first phase retarder 14 and is converted into circularly polarized light, including left circularly polarized light or right circularly polarized light. However, when part of the circularly polarized light is reflected back to the first phase retarder 14 by the partially penetrating and partially reflective element 16, it will become linearly polarized light, although it will pass through the first phase retarder 14 and be converted into circularly polarized light. However, after passing through the second phase retarder 18, it will still be converted into linearly polarized light.

Between the display screen 10 and the reflective polarizing element 12, at least one linear polarizer, circular polarizer or phase retarder can be added according to the polarization of the display screen 10 to adjust the polarization state of the display screen 10, and the new material It can be a thin film material or an optical coating, etc., which are provided on the display screen 10 or the reflective polarizing element 12 in the form of coating, coating, or bonding.

(1)

(2)

(3)

(4) 上述公式(3)可達到良好的像差校正，而公式(1)、(2)、(4)則可達到較大視角、系統距離縮短(輕薄化)之優點。 The present invention can achieve the effects of larger viewing angle, shorter system distance and good aberration correction. Please refer to Figure 2. The lens 22 is L, its effective focal length is f, the effective focal length of the optical system is F, and the half-view of the optical system The field angle is 𝜔, the visible range radius of the display screen 10 is H, R ₁ ~ R ₂ are the curvature radii of the left and right sides of the lens 22 respectively, the distance from the eye (aperture) to the center of the nearest element surface of the optical system is E, the total length of the optical system For TTL, the following formula can be obtained:

(1)

(2)

(3)

(4) The above formula (3) can achieve good aberration correction, while the formulas (1), (2), (4) can achieve the advantages of larger viewing angle and shorter system distance (light and thin).

Specific experimental data can be obtained from the implementation mode in Figure 2 as shown in Table 1: f = 24.646 H = 17 2ω = 93.4° f1 = 24.646 TTL = 22.7 surface Radius thickness Nd Vd radius lens stop Infinity 10 2 2 48.50639387 4.28 1.49000 57.4 15.5 L1 3 -15.78174855 0.5 17.5 4 unlimited 0.3 1.49000 57.4 17.5 5 unlimited 0.5 1.52000 64.2 17.5 6 unlimited 6.42 17.5 7 unlimited 0..08 1.49000 57.4 17.5 8 unlimited 0.5 1.52000 64.2 17.5 9 unlimited 0.12 1.49000 57.4 17.5 10 unlimited Aspherical lens surface K A B C D E 2 3.595 2.661E-05 -4.933E-08 -2.615E-10 -5.620E-13 9.260E-17 3 -5.158 -9.933E-05 7.300E-07 -2.227E-09 0.000E+00 0.000E+00 Table I

，其中C=1/R，R為曲率半徑。此外，表中f為光學系統之有效焦距，𝜔為光學系統之半視場角，H為顯示屏的可視範圍半徑，f1為透鏡的有效焦距，Nd為折射率(Refractive index)，Vd為阿貝數(Abbe number)或色散係數(V-number)。 A, B, C, D, E, etc. in the above table are the parameters in the aspheric formula, the aspheric formula is

, Where C=1/R, R is the radius of curvature. In addition, in the table, f is the effective focal length of the optical system, 𝜔 is the half angle of view of the optical system, H is the visible radius of the display screen, f1 is the effective focal length of the lens, Nd is the Refractive index, and Vd is A Abbe number (Abbe number) or dispersion coefficient (V-number).

In the present invention, the reflective polarizing element 12 and the partially penetrating and partially reflective element 16 can be coated on the lens 22 with a coating with a reflective polarization function, or a lens with a reflective polarization function or an optical film in the form of a film. The material is attached to the lens 22. Therefore, the present invention can attach the reflective polarizing element 12 to the first phase retarder 14, attach the reflective polarizing element 12 to the lens 22, and partially penetrate the partially reflective element 16. Attached to the first phase retarder 14, attaching the partially penetrating partially reflective element 16 to the second phase retarder 18, attaching the partially penetrating partially reflective element 16 to the lens 22, etc., so as to produce a variety of Different implementation styles.

In addition to the implementation aspects of Fig. 2, the following describes the implementation aspects of various different configurations of the lens 22 in Figs. 5A to 5C, but these implementation aspects do not limit the arrangement of the lens 22 in the present invention The method, as long as it is a structure in which at least one of the reflective polarizing element 12, the first phase retarder 14, the partially penetrating partially reflective element 16, the second phase retarder 18, and the linear polarizer 20 is provided with a lens 22 It is included in the scope of the present invention.

In the embodiment shown in Figure 5A, the lens 22 is provided between the first phase retarder 14 and the partially penetrating partially reflective element 16, and the partially penetrating partially reflective element 16 is provided on the lens 22. In addition, the present invention The second phase retarder 18 and the linear polarizer 20 can be integrated. For example, as shown in FIG. 5A, the second phase retarder 18 and the linear polarizer 20 are on the same side of the same lens 22, which can be equivalent For the function of the circular polarizer, the second phase retarder 18 and the linear polarizer 20 can be replaced by a circular polarizer. In this embodiment, a plate glass 26 is additionally added before the polarized light enters the human eye 24 for protection. The specific data of this embodiment are as follows in Table 2: f = 24.79 H = 17 2ω =82.3° f1 = 135.1 TTL = 32.47 surface Radius thickness Index Abbe. radius lens stop Infinity 10 2 2 unlimited 0.5 1.52000 64.0 twenty one 3 unlimited 0.3 1.49000 57.4 twenty one 4 unlimited 0.5 twenty one 5 88.03425936 4.34 1.49000 70.4 twenty one L1 6 -260.8417997 5.13 twenty one 7 unlimited 0.08 1.49000 57.4 twenty one 8 unlimited 0.12 1.49000 57.4 twenty one 9 unlimited 0.5 1.52000 64.0 twenty one 10 unlimited 11 twenty one 11 unlimited Aspherical lens surface K A B C 5 0.000 5.83E-07 1.48E-09 0.00E+00 6 0.000 3.17E-07 7.74E-09 6.75E-13 Table II

Figure 5B shows another embodiment. The reflective polarizing element 12 is provided on the first phase retarder 14, and the lens 22 is provided between the first phase retarder 14 and the partially penetrating partially reflective element 16, and the fifthA The embodiment in the figure is the same, the second phase retarder 18 and the linear polarizer 20 can be replaced by a circular polarizer, and a flat glass 26 is added before the polarized light enters the human eye 24. The specific data of this embodiment are as follows in Table 3: f = 23.3 H = 17 2ω = 98.39° f1 = 158.4 TTL = 33.3 surface Radius thickness Nd Vd radius lens stop Infinity 10 2 2 unlimited 0.5 1.52000 64.0 20 3 unlimited 0.3 1.49000 57.4 20 4 unlimited 0.5 20 5 77.53033929 5.5 1.49000 70.4 20 L1 6 unlimited 0.08 1.49000 57.4 20 7 unlimited 0.12 1.49000 57.4 20 8 unlimited 16.3 20 9 unlimited Table Three

In the embodiment shown in FIG. 5C, the lens 22 is provided between the reflective polarizing element 12 and the first phase retarder 14. The reflective polarizing element 12 of this embodiment is provided on the right side of the lens 22, and the partial reflective element 16 is partially penetrated. It can be arranged on the left side of the first phase retarder 14 or the right side of the second phase retarder 18. The second phase retarder 18 and the linear polarizer 20 can be replaced by a circular polarizer, which is the same as the embodiment in Fig. 5A. A flat glass 26 is added before the polarized light enters the human eye 24. The specific data of this embodiment are as follows in Table 4: f = 21.86 H = 17 2ω = 96.4 ° f1 = 107.4 TTL = 25.38 surface Radius thickness Nd Vd radius lens stop Infinity 10 2 2 unlimited 0.5 1.52000 64.0 21.3 3 unlimited 0.3 1.49000 57.4 21.3 4 unlimited 0.5 1.52000 64.2 21.3 5 unlimited 0.08 1.49000 57.4 21.3 6 unlimited 4.7 21.3 7 151.8207853 6 1.49000 70.4 21.3 L1 8 -79.34731414 3.3 21.3 9 unlimited Aspherical lens surface K A B C D 7 32.684 -4.961E-07 -3.690E-09 -1.327E-12 -3.377E-15 8 -0.380 -2.352E-07 3.054E-10 0.000E+00 0.000E+00 Table Four

The present invention uses the principle of polarization to internally refract and reflect the optical path in the optical system to achieve the effect of shortening the length of the optical system. As shown in the embodiment in Figure 2 and Figure 5A to Figure 5C, the polarized light is emitted from the display screen 10. The optical path of the optical module (not shown in the figure) after it is emitted to the human eye 24 undergoes multiple reflections. It is assumed that the total length of each reflection of the light from the display screen 10 to the optical module is d , It is almost the same as the optical path d from the display screen 10 to the optical module 23 in the prior art in FIG. 1, but because in the embodiment of FIG. 2 and FIG. 5A to FIG. 5C, the polarized light passes from the display screen 10 After being emitted, the section of light path to the optical module in front of the human eye 24 is obtained by the sum of multiple reflections. Therefore, in fact, the length from the display screen 10 to the optical module is much smaller than that from the display screen in Figure 1. 10 to the length of the optical module 23 to shorten the length of the optical system.

1.34 1.91 1.96 1.49

0.75 1.32 1.37 0.9

1.44 0.61 0.55 0.65

1.49 0.98 1.02 1.28 表五 The following table 5 shows the calculation results of the embodiment of Fig. 2 and Fig. 5A~5C with the above formulas (1)~(4). Example of Figure 2 Example of Figure 5A Example of Figure 5B Example of Figure 5C

1.34 1.91 1.96 1.49

0.75 1.32 1.37 0.9

1.44 0.61 0.55 0.65

1.49 0.98 1.02 1.28 Table 5

In summary, the miniaturized short-distance optical system provided by the present invention is to place a plurality of optical elements in sequence behind the display screen and in front of the optical module, using multiple reflections of light to achieve the purpose of shortening the length of the optical system, and using The phase retarder performs four phase delays, so that when the polarization state of the polarized light finally reaches the optical module, the phase of the polarization state emitted from the display screen is delayed by an integer multiple of a wavelength. The invention further utilizes the design of a single lens to achieve the purpose of miniaturization at a short distance while still maintaining good aberration correction. It is suitable for wide-angle lenses or wide-angle eyepieces, and the viewing angle can reach 50 degrees or more.

Only the above are merely preferred embodiments of the present invention, and are not used to limit the scope of the present invention. Therefore, all equivalent changes or modifications made in accordance with the characteristics and spirit of the application scope of the present invention shall be included in the patent application scope of the present invention.

10: Display 12: Reflective polarization element 14: The first phase retarder 16: Partially penetrated partly reflective element 18: The second phase retarder 20: Linear polarizer 22: lens 23: Optical module 24: Human Eye 26: flat glass

Figure 1 is a schematic diagram of the optical path between the display screen of the head mounted display and the human eye in the prior art. Figure 2 is a schematic diagram of an embodiment of the miniaturized short-distance optical system of the present invention. Figure 3 is an exploded view of an embodiment of the miniaturized short-distance optical system of the present invention Figures 4A to 4C are flow charts of the steps of the miniaturized short-distance optical system of the present invention. 5A to 5C are schematic diagrams of different configurations of a single lens in the miniaturized short-distance optical system of the present invention.

10: Display

12: Reflective polarization element

14: The first phase retarder

16: Partially penetrated partly reflective element

18: The second phase retarder

20: Linear polarizer

22: lens

24: Human Eye

Claims (12)

A miniaturized short-distance optical system, including: a display screen, which outputs images and emits polarized or unpolarized light; a reflective polarizing element, arranged corresponding to the display screen, so that the light partially penetrates and partially reflects; The phase retarder is set corresponding to the reflective polarizing element, receives the light partially penetrating the reflective polarizing element, and performs the first phase retardation; part penetrating the partially reflective element, corresponding to the first phase retarder setting, Part of the light that has undergone the first phase delay penetrates the part of the reflection element, and part of it is reflected back to the first phase retarder for the second and third phase delays; at least one optical element corresponds to the part The partially penetrating reflective element is arranged to receive the light partially penetrating the partially penetrating element and passing through the second and third phase delays, and perform the fourth phase delay, and then let the light after the fourth phase delay Light passes through but only two phase delays cannot pass through; and a lens arranged on any of the reflective polarizing element, the first phase retarder, the partially penetrating partially reflective element, and the optical element On one side, lead the image output by the display screen into at least one eye, where the visible radius of the display screen is H, the total length of the optical system is TTL, and the distance from the eye to the center of the closest element surface of the optical system is E , 0.3

3.2. The miniaturized short-distance optical system according to claim 1, wherein between the human eye and the lens can include one or more pieces of flat glass, and between the lens and the display screen can further include one or more pieces of flat glass, and One or more optical elements can be set on the flat glass The material can be a thin-film material or an optical coating, etc., which are arranged on the flat glass in the form of coating, coating or bonding. The miniaturized short-distance optical system according to claim 1, wherein the optical element includes: a second phase retarder disposed corresponding to the partially penetrating partially reflective element, and the receiving portion penetrates the partially penetrating partially reflective element and passes through The second and third phase retardation of the light, and the fourth phase retardation; and a linear polarizer, corresponding to the second phase retarder, the linear polarizer is used to allow only two phase retardation Do not let light pass through, and let light passing through the fourth phase delay. The miniaturized short-distance optical system according to claim 1, wherein the optical element may be a circular polarizer. The miniaturized short-distance optical system according to claim 3, wherein the light that partially penetrates the partially reflective element and is reflected back to the first phase retarder passes through the second phase retardation of the first phase retarder. The first phase retarder reaches the reflective polarizing element and completes reflection on the reflective polarizing element, so that the light is reflected back to the first retarder for a third phase retardation, and then the light passes through the The first phase retarder and the partially penetrating partially reflective element reach the second phase retarder, and the lens can be arranged on either side of the second phase retarder and the linear polarizer. The miniaturized short-distance optical system according to claim 3, wherein the first, second, third, and fourth phase delays are all increased by an odd multiple of 1/4 wavelength, so as to reach the human eye The light is delayed by an integer multiple of a wavelength. The miniaturized short-distance optical system according to claim 1, wherein when the light emitted from the display screen and entering the reflective polarizing element is polarized light, it can be linearly polarized light, circularly polarized light or other polarization states, and The display screen and the reflective polarizing element can be based on the The polarization of the display screen adds one or more linear polarizers, circular polarizers or phase retarders to adjust the polarization state of the display, which can be thin film materials or optical coatings in the form of coating, coating or bonding, etc. It is arranged on the display screen or the reflective polarizing element. The miniaturized short-distance optical system according to claim 7, wherein the linearly polarized light is converted into left circularly polarized light or right circularly polarized light after passing through the first phase retarder. The miniaturized short-distance optical system according to claim 1, wherein the visible range radius of the display screen is H, and the total length of the optical system is TTL, 0.9

2.9. The miniaturized short-distance optical system according to claim 1, wherein the effective focal length of the optical system is F, the radius of curvature of the side of the lens close to the eye is R ₁ , and the radius of curvature of the side close to the display screen is R ₂ , 0.4

1.95. The miniaturized short-distance optical system according to claim 1, wherein the effective focal length of the optical system is F, the half angle of view of the optical system is ω, and the total length of the optical system is TTL, 0.3

2.7. The miniaturized short-distance optical system according to claim 1, wherein the lens may be an aspheric lens, a Fresnel lens, or a combination of multiple lenses.

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