Ultra-short throw eyepiece system

Abstract

An ultra-short-distance eyepiece system includes a display screen, an optical module and a plurality of lenses, wherein the optical module includes a reflective polarizer, a first phase delay plate, a partially transparent and partially reflective element, a second phase delay plate and a linear polarizer arranged in sequence in front of the display screen, and the plurality of lenses include a first lens, a second lens and a third lens, and are respectively arranged on any side of at least one of the optical modules. The present invention utilizes multiple phase delays and reflections of light to achieve an ultra-short-distance optical architecture, and at the same time, by using this architecture with three lenses for focal length adjustment, good aberration performance and image quality can be achieved in a large field of view.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to an ultra-short-distance eyepiece system applicable to a 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, and the focal length is adjusted through the optical path to project the image to the eyes at a close distance, creating a virtual reality effect and increasing the wearer's sense of presence.

[0003] Figure 1 The diagram shows the eyepiece system of a virtual reality head-mounted display. The display screen 10 projects an image, which enters the lens 40 after passing through an optical path of an optical path of d. The lens 40 is a single lens or a combination of multiple lenses, which is used to guide the image into the user's human eye 24. Assuming that the optical path d is 40 mm, the length of the head-mounted display is the optical path d plus the thickness of the lens, the eye relief, the shell, etc. The sum is slightly bulky for the eye mask and helmet worn on the head, and will cause a burden on the user's nose bridge, the top of the head, and the neck, making it difficult to wear for a long time. Therefore, the technicians are currently committed to shortening the length of the eyepiece system in the head-mounted display to reduce the thickness of the head-mounted display and make it easier for users to wear.

[0004] In addition, in order for the virtual images provided by the head-mounted display to reproduce the visual effects, the eyepiece system must also provide high-standard image quality to meet consumers' visual needs for experiencing virtual reality. Summary of the invention

[0005] The main purpose of the present invention is to provide an ultra-short-distance eyepiece system, which adopts a three-lens design in the optical architecture to achieve a good aberration balance and improve the image quality, while also maintaining the ultra-short distance and wide viewing angle of the eyepiece system. This eyepiece system can be applied to wide-angle lenses or wide-angle eyepieces set on head-mounted displays, game consoles and other products, giving users a more perfect visual experience.

[0006] Another object of the present invention is to provide an ultra-short-distance eyepiece system, which has optical elements such as a reflective polarizer, a first phase delay plate, a partially transmissive and partially reflective element, a second phase delay plate, and a linear polarizer arranged in sequence behind a display screen and in front of a human eye, and utilizes multiple phase delays and reflections of light to shorten the overall length of the eyepiece system, which can be used to miniaturize a head-mounted display.

[0007] To achieve the above-mentioned purpose, the present invention provides an ultra-short-distance eyepiece system, including a display screen, an optical module and a plurality of lenses. The display screen is used to output images and emit light. The optical module includes: a reflective polarizer, which is arranged corresponding to the display screen, so that the vertical polarized light in the light is transmitted and the horizontal polarized light is reflected; a first phase delay plate, which is arranged corresponding to the reflective polarizer, receives the light that penetrates the reflective polarizer and performs a first phase delay; a partially penetrating partial reflection element, which is arranged corresponding to the first phase delay plate, so that the light that has undergone the first phase delay partially penetrates the aforementioned partially penetrating partial reflection element, and partially reflects back to the first phase delay plate for a second phase delay and a third phase delay; a second phase delay plate, which is arranged corresponding to the partially penetrating partial reflection element, receives the light that partially penetrates the aforementioned partially penetrating partial reflection element and undergoes the second phase delay and the third phase delay, and performs a fourth phase delay; and a linear polarizer, which is arranged corresponding to the second phase delay plate, so that the light that has undergone only two phase delays does not pass through and only allows the light that has undergone four phase delays to pass through. The plurality of lenses include a first lens, a second lens, and a third lens, which are respectively disposed on either side of at least one of the optical modules to direct the image output by the display screen into at least one eye of the person, and the third lens is the lens closest to the display screen, and the first lens is the lens closest to the eye of the person; at the same time, the ultra-short-throw eyepiece system must meet the following conditions (1) and (2):

[0008] (1) and

[0009] (2)

[0010] Wherein, f1 is the effective focal length of the first lens;

[0011] f2 is the effective focal length of the second lens;

[0012] f3 is the effective focal length of the third lens;

[0013] F is the effective focal length of the ultra-short-throw eyepiece system;

[0014] R1 is the radius of curvature of the first lens on the side close to the human eye;

[0015] R2 is the radius of curvature of the first lens on the side close to the display screen;

[0016] R3 is the radius of curvature of the second lens on the side close to the human eye;

[0017] R4 is the radius of curvature of the second lens on a side close to the display screen;

[0018] R5 is the radius of curvature of the side of the third lens close to the human eye; and

[0019] R6 is the curvature radius of the third lens on a side close to the display screen.

[0020] According to an embodiment of the present invention, the lens comprises a single lens or a multi-lens, wherein the single lens is a spherical lens, an aspherical lens or a Fresnel lens, and the multi-lens is composed of at least one of a spherical lens, an aspherical lens and a Fresnel lens.

[0021] According to an embodiment of the present invention, the ultra-short-throw eyepiece system further satisfies any one of the following conditions (3) to (6):

[0022] (3)

[0023] (4)

[0024] (5) and

[0025] (6)

[0026] Among them, f s4 is the focal length of the reflective surface of the partially penetrating reflective element;

[0027] f s5 is the focal length of the reflective surface of the reflective polarizer;

[0028] TTL is the total length of the ultra-short throw eyepiece system; and

[0029] ω is the half-field viewing angle of the ultra-short-throw eyepiece system.

[0030] According to an embodiment of the present invention, at least one of the reflective polarizer, the first phase retarder, the partially reflective and partially transmissive element, the second phase retarder and the linear polarizer is a thin film material or an optical coating, and is disposed on at least one of the aforementioned lenses or at least one flat glass by coating, coating or bonding.

[0031] According to an embodiment of the present invention, the first polarized light that partially penetrates the partially reflective element and is reflected back to the first phase retarder undergoes a second phase delay by the first phase retarder, passes through the first phase retarder to reach the reflective polarizer, completes reflection on the reflective polarizer, and then reflects back to the first phase retarder for a third phase delay to form a second polarized light. The second polarized light passes through the first phase retarder and partially penetrates the partially reflective element to reach the second phase retarder.

[0032] According to an embodiment of the present invention, the first, second, third and fourth phase delays all increase the phase delay by an odd multiple of 1 / 4 wavelength, so that the light reaching the human eye is delayed by an integer multiple of 1 wavelength.

[0033] According to an embodiment of the present invention, the light emitted from the display screen and entering the reflective polarizer is linearly polarized light; further, the linearly polarized light is converted into left circularly polarized light or right circularly polarized light after passing through the first phase retarder.

[0034] According to an embodiment of the present invention, the light emitted from the display screen and entering the reflective polarizer is circularly polarized light, and a third phase retarder or a circular polarizer is further provided between the display screen and the reflective polarizer so that the circularly polarized light is converted into linearly polarized light after passing through the third phase retarder or the circular polarizer.

[0035] According to an embodiment of the present invention, the light emitted from the display screen and entering the reflective polarizer is non-polarized light, and another linear polarizer is disposed between the display screen and the reflective polarizer so that the non-polarized light is converted into linear polarized light after passing through the other linear polarizer.

[0036] The following detailed description is made through specific embodiments to make it easier to understand the purpose, technical content, characteristics and effects achieved by the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] Figure 2 Schematic diagram of an embodiment of an ultra-short-throw eyepiece system of the present invention.

[0039] FIG. 3A to FIG. 3C 4 is a flow chart of the steps of the ultra-short-distance eyepiece system of the present invention.

[0040] FIG. 4A to FIG. 4E Schematic diagram of different configurations of three lenses in the ultra-short-throw eyepiece system of the present invention.

[0041] Explanation of the reference numerals: 10 - display screen; 12 - reflective polarizer; 14 - first phase retarder; 16 - partially penetrating and partially reflecting element; 18 - second phase retarder; 20 - linear polarizer; 22 - lens; 24 - human eye; 26 - flat glass; 30 - first lens; 32 - second lens; 34 - third lens; 40 - lens; d - optical path. DETAILED DESCRIPTION

[0042] The present invention provides an ultra-short-distance eyepiece system for use in a head-mounted display. The system utilizes a plurality of optical elements to reflect light multiple times, and a plurality of lenses are used in the optical elements. The system can effectively achieve aberration balance, improve image quality, and shorten the overall eyepiece system at the same optical path length, thereby miniaturizing the head-mounted display.

[0043] Please refer to Figure 2, which is a schematic diagram of an embodiment of the ultra-short-distance eyepiece system of the present invention. The ultra-short-distance eyepiece system of this embodiment includes a reflective polarizer 12, a first phase retardation plate 14, a partially transparent and partially reflective element 16, a second phase retardation plate 18, a linear polarizer 20 and three lenses 22 in sequence between a display screen 10 and at least a human eye 24. Among them, the display screen 10 outputs an image and emits light, which is polarized light or non-polarized light. When the light is polarized light, the polarized light can be linearly polarized light, circularly polarized light or other polarization states; in this embodiment, the polarized light is linearly polarized light. Further, the polarization direction of the linear polarized light in this embodiment is perpendicular to the optical path; the reflective polarizer 12 is arranged corresponding to the display screen 10, receives the polarized light emitted by the display screen 10, and partially transmits and partially reflects the polarized light. In particular, the reflective polarizer 12 used in the present invention includes two polarization directions perpendicular to and parallel to the optical path, the vertical direction is the transmission axis, and the horizontal direction is the reflection axis; the first phase retarder 14 is arranged corresponding to the reflective polarizer 12, and is used to receive the polarized light partially transmitted from the reflective polarizer 12, and perform the first phase delay; the partially penetrating and partially reflecting element 16 is arranged corresponding to the first phase retarder 14, receives the light passing through the first phase retarder 14, and partially reflects and partially transmits the light passing through; the second phase retarder 18 is arranged corresponding to the partially penetrating and partially reflecting element 16, receives the light partially transmitted through the partially reflecting element 16, and performs phase delay; the linear polarizer 20 is arranged corresponding to the second phase retarder 18, and the linear polarizer 20 is used to prevent the polarized light that has only undergone two phase delays from passing through and only allow the polarized light that has undergone four phase delays to pass through, and introduce the image into the human eye 24 through the lens 22.

[0044] Particularly, the fast and slow axes of the first phase retarder 14 of the present invention are at an angle of 45 degrees to the transmission axis of the reflective polarizer 12, which can increase the phase retardation by 1 / 4 wavelength.

[0045] In addition, the three lenses 22 of the present invention are respectively arranged on either side of at least one element in the optical module to Figure 2 For example, three lenses 22 are disposed between the partially transmissive and partially reflective element 16 and the first phase retarder 14. Each lens can be a single lens or a multi-lens; specifically, the lens can be a single lens selected from a spherical lens, an aspherical lens, and a Fresnel lens, or a multi-lens selected from a spherical lens, an aspherical lens, and a Fresnel lens.

[0046] For specific steps in the present invention, please refer to FIG. 3A to FIG. 3C , first in Figure 3AIn the embodiment, the display screen 10 outputs an image and emits polarized light to the reflective polarizer 12. The reflective polarizer 12 allows the polarized light to partially penetrate the first phase retarder 14 and partially reflect back to the display screen 10. The partially penetrated polarized light that penetrates the reflective polarizer 12 undergoes a first phase delay after passing through the first phase retarder 14 and then reaches the partially penetrating and partially reflecting element 16. Please refer to Figure 3B The polarized light that has undergone the first phase delay partially penetrates the partially penetrating and partially reflecting element 16, and partially reflects back to the first phase delay plate 14 for the second phase delay. The polarized light that has partially penetrated the partially reflecting element 16 is energy loss, and the polarized light that has undergone the first phase delay penetrates the first phase delay plate 14 and reaches the reflective polarizer 12; please refer to Figure 3C The reflective polarizer 12 reflects the polarized light that has undergone the second phase delay, reflects it back to the first phase delay plate 14, undergoes the third phase delay, and then passes through the partially penetrating partially reflecting element 16. The partially penetrating polarized light (after the third phase delay) reaches the second phase delay plate 18 and undergoes the fourth phase delay. Then, the polarized light that has undergone the fourth phase delay penetrates the second phase delay plate 18 and is screened by the linear polarizer 20, so that only the polarized light that has undergone four phase delays passes through the linear polarizer 20 and is guided into at least one human eye 24 by the lens 22.

[0047] Since the first phase retarder 14 and the second phase retarder 18 in the present invention both have an odd-numbered phase delay of 1 / 4 wavelength, they are delayed by an integer multiple of a wavelength after four phase delays.

[0048] After passing through the first phase retarder 14, the linearly polarized light will be 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 reflecting element 16, it will be converted into linearly polarized light again. Although it will pass through the first phase retarder 14 again and be converted into circularly polarized light, it will still be converted back into linearly polarized light after passing through the second phase retarder 18.

[0049] In addition, the present invention can further add one or more linear polarizers, circular polarizers or phase retarders between the display screen 10 and the reflective polarizer 12 according to the polarization condition of the display screen 10 to adjust the polarization state of the display screen 10, and the material of the linear polarizer, circular polarizer and phase retarder can be a thin film material or an optical coating, which can be disposed on the display screen 10 or the reflective polarizer 12 in the form of coating, coating or bonding. For example, if the light emitted by the display screen 10 is not linearly polarized light but circularly polarized light, a third phase retarder or a circular polarizer needs to be added after the display screen 10, so that the circularly polarized light emitted by the display screen 10 is converted into linearly polarized light after passing through the third phase retarder or circular polarizer; or, if the light emitted by the display screen 10 is non-polarized light without a specific polarization state, another linear polarizer needs to be added after the display screen 10, so that the non-polarized light emitted by the display screen 10 is converted into linearly polarized light after passing through the linear polarizer.

[0050] FIG. 4A to FIG. 4E 2 is an embodiment of a plurality of different configuration methods of three lenses, wherein the three lenses are a first lens 30, a second lens 32 and a third lens 34, wherein the third lens 34 is the lens closest to the display screen 10, and the first lens 30 is the lens closest to the human eye 24. This embodiment is not intended to limit the configuration method of the lenses in the present invention, as long as a lens is disposed on any side of at least one of the reflective polarizer 12, the first phase retarder 14, the partially transmissive and partially reflective element 16, the second phase retarder 18 and the linear polarizer 20, a total of at least three sets of lenses for focusing are included in the scope of the present invention.

[0051] To further illustrate, the reflective polarizer 12, the first phase retarder 14, the partially transparent and partially reflective element 16, the second phase retarder 18 and the linear polarizer 20 and other optical elements may be made of thin film materials or optical coatings, etc., and may be placed on at least one of the lenses or at least one flat glass in the form of coating, plating or bonding. For example, the reflective polarizer 12 and the partially transparent and partially reflective element 16 may be coatings on the lens, or lenses with reflective polarization functions themselves or optical materials in the form of thin films attached to the lens. Therefore, the present invention may integrate the reflective polarizer 12 and the first phase retarder 14, and integrate the partially transparent and partially reflective element 16 and the second phase retarder 18. For example, Figure 4AAs shown, the reflective polarizer 12 and the first phase retarder 14 are the same lens group 34 (the third lens group 34 in this embodiment is a single lens), for example, a reflective polarizer film is set on the side of the first phase retarder 14 close to the display screen 10, or a special material is used to achieve the same lens having the functions of phase retardation and reflective polarization, and on the left side of the first lens group 30, a partially transparent and partially reflective element 16 (a partially transparent and partially reflective film in this embodiment), a second phase retarder 18, a linear polarizer 20 and a flat glass 26 are sequentially arranged. In other words, Figure 4A In the embodiment, the first lens 30 is disposed between the second lens 32 and the partially transmissive and partially reflective element 16, the second lens 32 is disposed between the first lens 30 and the third lens 34, and the third lens 34 is disposed between the second lens 32 and the reflective polarizer 12 and the first phase retarder 14. Specific data of this embodiment are shown in Tables 1 and 2:

[0052]

[0053] Table 1. Lens parameters

[0054]

[0055] Table 2. Aspheric coefficients

[0056] A, B, C, D, E, K, etc. in Table 2 above are the parameters in the aspheric formula. The aspheric formula is Where C = 1 / R, R is the radius of curvature, and K is the cone coefficient. In addition, L1, L2, and L3 in the table represent the first, second, and third lenses, respectively. f1, f2, and f3 represent the effective focal lengths of the first, second, and third lenses, respectively. s4 is the focal length of the reflective surface of the partially penetrating and partially reflecting element, f s5 is the focal length of the reflective surface of the reflective polarizer, f is the effective focal length of the ultra-short-throw eyepiece system, ω is the half field angle of the ultra-short-throw eyepiece system, TTL is the total length of the ultra-short-throw eyepiece system, Nd is the refractive index, and Vd is the Abbe number or dispersion coefficient (V-number).

[0057] Figure 4B Another embodiment is shown, the reflective polarizer 12 and the first phase retarder 14 are both disposed on the right side of the second lens 32, and the partially transmissive and partially reflective element 16, the second phase retarder 18 and the linear polarizer 20 are all disposed on the left side of the first lens 30. The specific data of this embodiment are shown in Tables 3 and 4 below:

[0058]

[0059] Table 3. Lens parameters

[0060]

[0061] Table 4. Aspheric coefficients

[0062] Figure 4C , Figure 4D and Figure 4E There are three other configurations of the first lens 30, the second lens 32 and the third lens 34. Since the first lens 30, the second lens 32 and the third lens 34 can be a single lens or a combination of multiple lenses, and can be concave lenses, convex lenses, etc., and the concave and convex directions can also be changed, a variety of different combinations can be generated.

[0063] Figure 4C In the embodiment, the reflective polarizer 12 and the first phase retarder 14 are arranged on the left side of the third lens 34, the left side of the first phase retarder 14 is the second lens 32, and the partially transparent and partially reflecting element 16, the second phase retarder 18 and the linear polarizer 20 are all arranged on the left side of the third lens. The specific data of this embodiment are shown in Tables 5 and 6:

[0064]

[0065] Table 5. Lens parameters

[0066]

[0067] Table 6. Aspheric coefficients

[0068] Figure 4D In the embodiment, and Figure 4C The difference between the embodiment of the present invention and the embodiment of the present invention is that the second phase retarder 18 and the linear polarizer 20 of this embodiment are made into independent components. The specific data of this embodiment are as follows in Tables 7 and 8:

[0069]

[0070]

[0071] Table 7. Lens parameters

[0072]

[0073] Table 8. Aspheric coefficients

[0074] Figure 4E In the embodiment, the reflective polarizer 12 and the first phase retarder 14 are made into independent components and are arranged on the right side of the third lens 34. The partially transparent and partially reflecting element 16, the second phase retarder 18 and the linear polarizer 20 are arranged on the right side of the first lens 30 in sequence. The specific data of this embodiment are shown in Table 9 and Table 10:

[0075]

[0076] Table 9. Lens parameters

[0077]

[0078] Table 10. Aspheric coefficients

[0079] Further explanation, the present invention can integrate the second phase retarder 18 and the linear polarizer 20. For example, Figure 4E As shown, the second phase retarder 18 and the linear polarizer 20 are both on the same side of the same lens 30 , which can be equivalent to the function of a circular polarizer.

[0080] The ultra-short-distance eyepiece system of the present invention can achieve the effects of a larger viewing angle, a shorter system distance and good aberration correction. Please refer to Figure 4A , the ultra-short-throw eyepiece system must meet the following conditions (1) and (2):

[0081] (1) and

[0082] (2)

[0083] Wherein, f1 is the effective focal length of the first lens;

[0084] f2 is the effective focal length of the second lens;

[0085] f3 is the effective focal length of the third lens;

[0086] F is the effective focal length of the ultra-short-throw eyepiece system;

[0087] R1 is the radius of curvature of the first lens on the side close to the human eye;

[0088] R2 is the radius of curvature of the first lens on the side close to the display screen;

[0089] R3 is the radius of curvature of the second lens on the side close to the human eye;

[0090] R4 is the radius of curvature of the second lens on a side close to the display screen;

[0091] R5 is the radius of curvature of the side of the third lens close to the human eye; and

[0092] R6 is the curvature radius of the third lens on a side close to the display screen.

[0093] Preferably, the ultra-short-throw eyepiece system of the present invention satisfies any one of the following conditions (3) to (6):

[0094] (3)

[0095] (4)

[0096] (5) and

[0097] (6)

[0098] Among them, f s4 is the focal length of the reflective surface of the partially penetrating reflective element;

[0099] f s5 is the focal length of the reflective surface of the reflective polarizer;

[0100] TTL is the total length of the ultra-short throw eyepiece system; and

[0101] ω is the half-field viewing angle of the ultra-short-throw eyepiece system.

[0102] The above conditions (1), (3) and (4) can reduce the thickness of the system and achieve an optical magnification effect. Condition (2) can achieve a good aberration balance and obtain better image quality. Conditions (5) and (6) can achieve the advantages of a larger viewing angle and thinness.

[0103] The present invention uses the polarization principle to make the light path do internal refraction and reflection in the optical system to achieve the effect of shortening the distance between the display screen and the human eye. FIG. 4A to FIG. 4E For example, the optical path of the polarized light from the display screen 10 to the optical element in front of the human eye 24 undergoes multiple reflections. FIG. 4A to FIG. 4E In the embodiment of FIG. 1 , the optical path length after the sum of each reflection length of the light from the display screen 10 to the optical element in front of the human eye 24 is d, which is Figure 1 In the prior art, the optical path d from the display screen 10 to the lens 22 is almost the same, but due to FIG. 4A to FIG. 4E In the embodiment, the optical path from the display screen 10 to the human eye is obtained by summing up multiple reflections, so the actual length from the display screen 10 to the human eye is much shorter than Figure 1 The length from the display screen 10 to the human eye 24 is reduced, thereby achieving the purpose of shortening the length of the optical system.

[0104] In summary, the ultra-short distance eyepiece system provided by the present invention utilizes multiple phase delays and reflections of light to achieve an ultra-short distance optical architecture. At the same time, by using three lenses on this architecture for focal length adjustment, good aberration performance and image quality can be achieved at short distances and large fields of view. Furthermore, the ultra-short distance eyepiece system provided by the present invention can be used for myopia adjustment, with an imaging range of Φ7mm to Φ52mm, and is suitable for screens of 0.3 inches to 3 inches, providing a higher image quality for small-size screens. Moreover, since the length of the eyepiece system is shortened, the product using the optical system can achieve the purpose of being thin and light, and miniaturized, and is particularly suitable for wide-angle lenses or wide-angle eyepieces on head-mounted displays, game consoles, and other products.

[0105] 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 ultra-short-distance eyepiece system, characterized in that: include: A display screen that outputs images and emits light; An optical module, comprising: a reflective polarizer, arranged corresponding to the display screen, receiving the light from the display screen, and allowing the light to partially penetrate and partially reflect; a first phase retarder, arranged corresponding to the reflective polarizer, receiving a portion of the light penetrating the reflective polarizer and performing a first phase retarder; A partially penetrating partially reflecting element is disposed corresponding to the first phase retarder, so that the light that has undergone the first phase delay partially penetrates the partially penetrating partially reflecting element and partially reflects back to the first phase retarder for second and third phase delays; a second phase delay plate, arranged corresponding to the partially penetrating partially reflecting element, receiving the light that partially penetrates the partially penetrating partially reflecting element and undergoes the second phase delay and the third phase delay, and performs the fourth phase delay; and a linear polarizer, arranged corresponding to the second phase delay plate, for preventing the light that has undergone only two phase delays from passing through and only allowing the light that has undergone four phase delays to pass through; and a plurality of lenses, including a first lens, a second lens, and a third lens, respectively arranged on either side of at least one of the optical modules, for guiding the image output by the display screen into at least one person's eye, wherein the third lens is the lens closest to the display screen, and the first lens is the lens closest to the person's eye; The first lens, the second lens, and the third lens are single-piece lenses or multi-piece lenses; the single-piece lens is a spherical lens or an aspherical lens; the multi-piece lens is composed of at least one of a spherical lens and an aspherical lens; The ultra-short-throw eyepiece system satisfies the following conditions (1) and (2): (1) and (2) Wherein, f1 is the effective focal length of the first lens; f2 is the effective focal length of the second lens; f3 is the effective focal length of the third lens; F is the effective focal length of the ultra-short-throw eyepiece system; R1 is the radius of curvature of the first lens on the side close to the human eye; R2 is the radius of curvature of the first lens on the side close to the display screen; R3 is the radius of curvature of the second lens on the side close to the human eye; R4 is the radius of curvature of the second lens on a side close to the display screen; R5 is the radius of curvature of the side of the third lens close to the human eye; and R6 is the radius of curvature of the side of the third lens close to the display screen; At least one of the reflective polarizer, the first phase retarder, the partially reflective and partially transmissive element, the second phase retarder and the linear polarizer is a thin film material or an optical coating, and is disposed on at least one of the multiple lenses or at least one flat glass in a coating, coating or bonding manner.

2. The ultra-short-distance eyepiece system according to claim 1, wherein: Furthermore, any one of the following conditions (3) to (6) is satisfied: (3) (4) (5) and (6) Wherein, fs4 is the focal length of the reflective surface of the partially penetrating reflective element; fs5 is the focal length of the reflective surface of the reflective polarizer; TTL is the total length of the ultra short throw eyepiece system; and ω is the half field viewing angle of the ultra short throw eyepiece system.

3. The ultra-short-distance eyepiece system according to claim 1, wherein: The light reflected back to the first phase retarder by the partially penetrating partially reflecting element undergoes the second phase delay of the first phase retarder, passes through the first phase retarder to reach the reflective polarizer, and completes reflection on the reflective polarizer, allowing the light to be reflected back to the first phase retarder for the third phase delay, and then the light passes through the first phase retarder and the partially penetrating partially reflecting element to reach the second phase retarder.

4. The ultra-short-distance eyepiece system according to claim 1, wherein: The first phase delay, the second phase delay, the third phase delay, and the fourth phase delay all increase the phase delay by an odd multiple of a quarter wavelength, so that the light reaching the human eye is delayed by an integer multiple of a wavelength.

5. The ultra-short-distance eyepiece system according to claim 1, wherein: The light emitted from the display screen and entering the reflective polarizer is linearly polarized light.

6. The ultra-short-distance eyepiece system according to claim 5, characterized in that: The linearly polarized light is converted into left circularly polarized light or right circularly polarized light after passing through the first phase retarder.

7. The ultra-short-distance eyepiece system according to claim 1, wherein: The light emitted from the display screen and entering the reflective polarizer is circularly polarized light. A third phase retarder or a circular polarizer is further provided between the display screen and the reflective polarizer so that the circularly polarized light is converted into linearly polarized light after passing through the third phase retarder or the circular polarizer.

8. The ultra-short-distance eyepiece system according to claim 1, wherein: The light emitted from the display screen and entering the reflective polarizer is non-polarized light. Another linear polarizer is arranged between the display screen and the reflective polarizer so that the non-polarized light is converted into linear polarized light after passing through the other linear polarizer.

Images