TWI797563B - Ultra short distance eyepiece system - Google Patents

Abstract

An ultra-short-distance eyepiece system, which includes a display screen, an optical module and multiple lenses, the optical module includes a reflective polarizer, a first phase retarder, and a partially penetrating partially reflective element arranged in sequence in front of the display screen . A second phase retarder and a linear polarizer. The plural lenses include a first lens, a second lens and a third lens, and are respectively arranged on either side of at least one of the optical modules. The present invention realizes an ultra-short-distance optical structure by performing multiple phase delays and reflections on light rays. At the same time, by using this structure with three lenses for focal length adjustment, good aberration performance and image quality can be achieved in a large field of view. quality.

Description

Ultra short distance eyepiece system

The invention relates to the field of optical technology, in particular to an ultra-short-distance eyepiece system applicable 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 goggles or helmets, the display is close to the user's eyes, and the focal length is adjusted through the optical path to project on the eyes at a close distance. The screen can produce the effect of virtual reality and increase the sense of presence of the wearer.

FIG. 1 is a schematic diagram of the eyepiece system of a head-mounted display in virtual reality. The image projected from the display screen 10 is incident on the lens 40 after passing through a light path with an optical path of d. The lens 40 is a single lens or a plurality of lenses. combined to guide the image into the user's eyes 24 . Assuming that the optical path d is 40mm, the length of the head-mounted display is the optical path d plus the thickness of the lens, eye distance, casing, etc. The bridge of the nose, the top of the head, and the neck will cause a burden and cannot be worn for a long time. Therefore, technical personnel are currently working on shortening the length of the eyepiece system in the head-mounted display, so as to reduce the thickness of the head-mounted display and make it easier for users to wear it.

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

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 structure, so as to achieve a good aberration balance and improve image quality, while maintaining the ultra-short-distance and large viewing angle of the eyepiece system. This eyepiece system can be applied to wide-angle lenses or wide-angle eyepieces installed on head-mounted displays, game consoles and other products to give users a more perfect visual experience.

Another object of the present invention is to provide an ultra-short-distance eyepiece system, which sequentially arranges a reflective polarizer, a first phase retardation film, a partially penetrating partial reflection element, and a second phase retardation film behind the display screen and in front of the human eye. Optical components such as linear polarizers and linear polarizers use multiple phase delays and reflections of light to shorten the overall length of the eyepiece system, which can be used to miniaturize head-mounted displays.

；及 （2）

.15； 其中，f ₁為第一透鏡之有效焦距； f ₂為第二透鏡之有效焦距； f ₃為第三透鏡之有效焦距； F為超短距目鏡系統之有效焦距； R ₁為第一透鏡靠近人眼之一側之曲率半徑； R ₂為第一透鏡靠近顯示屏之一側之曲率半徑； R ₃為第二透鏡靠近人眼之一側之曲率半徑； R ₄為第二透鏡靠近顯示屏之一側之曲率半徑； R ₅為第三透鏡靠近人眼之一側之曲率半徑；及 R ₆為第三透鏡靠近顯示屏之一側之曲率半徑。 To achieve the above purpose, the present invention provides an ultra-short-distance eyepiece system, which includes a display screen, an optical module and a plurality of lenses. Wherein, the display screen is used for outputting images and emitting light. The optical module includes: a reflective polarizer, which is set corresponding to the display screen, so that the vertically polarized light in the light can pass through and the horizontally polarized light can be reflected; The light from the first phase retardation film is delayed for the first time; a part of it penetrates the partial reflection element, and is set corresponding to the first phase retardation film, so that part of the light rays of the first phase delay penetrates the aforementioned part and penetrates the partial reflection element, and part of it passes through the partial reflection element Reflected back to the first phase retarder for the second and third phase delays; a second phase retarder, corresponding to the partial penetrating part of the reflective element, the aforementioned part of the receiving part penetrates through the partial reflective element and passes through the second , the light with the third phase delay, and the fourth phase delay; and a first-line polarizer, which is set corresponding to the second phase retarder, so that the light that has only undergone two phase delays does not pass through and only passes through the four phases Delayed rays pass through. The plural lenses include a first lens, a second lens and a third lens, which are respectively arranged on either side of at least one of the optical modules, and guide the image output by the display screen into at least one human eye, and the third lens It is the lens closest to the display screen, and the first lens is the lens closest to the human eye; at the same time, the ultra-short-distance eyepiece system must meet the following conditions (1) and (2): (1)

and (2)

.15; Among them, f ₁ is the effective focal length of the first lens; f ₂ is the effective focal length of the second lens; f ₃ is the effective focal length of the third lens; F is the effective focal length of the ultra-short distance eyepiece system; R ₁ is the effective focal length of the second lens The radius of curvature of the side of a lens close to the human eye; R ₂ is the radius of curvature of the first lens close to the display screen; R ₃ is the radius of curvature of the second lens close to the side of the human eye; R ₄ is the radius of curvature of the second lens The radius of curvature of the 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.

According to an embodiment of the present invention, the aforementioned lens includes a single-piece lens or a multi-piece lens. Wherein, the single lens is a spherical lens, an aspheric lens or a Fresnel lens; the multi-chip lens is composed of at least one of a spherical lens, an aspheric lens and a Fresnel lens.

； （4）

，

； （5）

；及 （6）

； 其中，

為部分穿透部分反射元件反射面之焦距；

為反射式偏振片反射面之焦距； TTL為超短距目鏡系統之總長；及

為超短距目鏡系統之半場視角。 According to the embodiment of the present invention, the ultra-short-distance eyepiece system further satisfies any one of the following conditions (3) to (6): (3)

;(4)

,

; (5)

and (6)

; in,

is the focal length of the reflective surface of the partially penetrating part of the reflective element;

is the focal length of the reflecting surface of the reflective polarizer; TTL is the total length of the ultra-short-throw eyepiece system; and

It is the half-field angle of view of the ultra-short-distance eyepiece system.

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 film material or an optical coating, and is coated, The method of coating or bonding is arranged on at least one of the aforementioned lenses or at least one plate glass.

According to an embodiment of the present invention, the first polarized light that partially passes through the partial reflection element and is reflected back to the first phase retarder passes through the first phase retarder to reach the reflective polarized light after the second phase delay of the first phase retarder. plate, and complete the reflection on the reflective polarizer, and then reflect back to the first phase retarder for the third phase delay to form the second polarized light, the second polarized light passes through the first phase retarder and partially penetrates the partial reflection element to the second phase retarder.

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

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.

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 to make the circularly polarized light After passing through the third phase retarder or circular polarizer, it is converted into linearly polarized light.

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 further provided between the display screen and the reflective polarizer, so that the unpolarized light passes through this other linear polarization post-conversion to linearly polarized light.

In the following detailed description by means of specific embodiments, it will be easier to understand the purpose, technical content, characteristics and effects of the present invention.

The present invention provides an ultra-short-distance eyepiece system, which is applied to a head-mounted display. It uses multiple optical elements to reflect light multiple times, and these optical elements are equipped with multiple lenses, which can effectively achieve aberration balance and improve image quality. quality, shorten the overall eyepiece system with the same length of light path, and miniaturize the head-mounted display.

Please refer to FIG. 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 retarder 14, a part of the penetrating partial reflection element 16, a first Two phase retarders 18 , one line polarizer 20 and three lenses 22 . Wherein, the display screen 10 outputs images 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 , polarized light is linearly polarized light. Further, the polarization direction of the linearly 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 , especially the reflective polarizer 12 adopted in the present invention includes two kinds of polarization directions vertical and parallel to the optical path, the vertical axis is the transmission axis, and the horizontal axis is the reflection axis; the first phase retarder 14 is set corresponding to the reflective polarizer 12, with To receive the polarized light partially penetrating from the reflective polarizer 12, and perform the first phase retardation; the partially penetrating partial reflection element 16 is set corresponding to the first phase retarder 14, and receives the light passing through the first phase retarder 14 And partly reflect and partly penetrate the passing light; the second phase retarder 18 is set corresponding to the partly penetrating partly reflecting element 16, and receives the light partly penetrating partly reflecting partly 16, and carries out phase retardation; the linear polarizer 20 corresponds to the first Two phase retarders 18 are set, 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 the image is introduced into the human eye 24 through the lens 22 .

In particular, in the present invention, the fast and slow axes of the first phase retarder 14 and the transmission axis of the reflective polarizer 12 form an angle of 45 degrees, which can increase the phase delay of 1/4 wavelength.

In addition, the three lenses 22 in the present invention are respectively arranged on either side of at least one element in the optical module. Taking the embodiment in Fig. 2 as an example, the three lenses 22 are arranged on the partly penetrating part reflective element 16 and the first Between the phase retarder 14. Each lens can be a single-piece lens or a multi-piece lens; specifically, the lens can be a single-piece lens in a spherical lens, an aspheric lens, and a Fresnel lens (Fresnel lens), or it can be made of a spherical lens. A multi-piece lens composed of at least one of lens, aspheric lens and Fresnel lens.

Please refer to Fig. 3A to Fig. 3C for the specific steps of the present invention. First, in Fig. 3A, the display screen 10 outputs an image and sends polarized light to the reflective polarizer 12. The reflective polarizer 12 makes the polarized light part After passing through the first phase retarder 14, part of it is reflected back to the display screen 10, and the partially transmitted polarized light that passes through the reflective polarizer 12 will undergo the first phase retardation after passing through the first phase retarder 14, Then, please refer to the 3B figure, the polarized light through the first phase retardation is partially penetrated at the partly penetrating part reflective element 16, and the part is reflected back to the first phase retarder 14 for further processing. The second phase delay, the polarized light that partially penetrates the partial reflection element 16 here is energy loss, and the polarized light that passes through the first phase delay penetrates the first phase retarder 14 and reaches the reflective polarizer 12; then Please refer to Fig. 3C again, the reflective polarizer 12 reflects the polarized light that has undergone the second phase retardation, reflects it back to the first phase retarder 14, performs the third phase retardation, and then passes through the partially penetrating partial reflection element 16 , the partially transmitted polarized light (through the third phase retardation) reaches the second phase retarder 18, and undergoes the fourth phase retardation; then, the polarized light through the fourth phase retardation penetrates the second phase retarder 18. Screening by the linear polarizer 20, 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.

Since the first phase retardation film 14 and the second phase retardation film 18 in the present invention are both odd multiples of 1/4 wavelength, they are retarded by an integer multiple of a wavelength after four phase delays.

The linearly polarized light will be transformed into circularly polarized light after passing through the first phase retarder 14 , including left circularly polarized light and right circularly polarized light. However, when part of the circularly polarized light is reflected back to the first phase retarder 14 by partly penetrating the partial reflection element 16, it will become linearly polarized light again, 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 back-linearly polarized light.

In addition, the present invention can 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 of the display screen 10 to adjust the polarization of the display screen 10. state, and the material of linear polarizer, circular polarizer and phase retarder can be thin film material or optical coating, which can be arranged on display screen 10 or 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 behind the display screen 10, so that the circularly polarized light emitted by the display screen 10 passes through the The third phase retarder or circular polarizer is converted into linearly polarized light; or, if the light emitted by the display screen 10 is unpolarized light without a specific polarization state, another linear polarizer needs to be added behind the display screen 10, The unpolarized light emitted by the display screen 10 is converted into linearly polarized light after passing through the linear polarizer.

Figures 4A to 4E are examples of various configurations of the three lenses. The three lenses are the first lens 30, the second lens 32, and the third lens 34, and the third lens 34 is the closest to the display screen. 10, the first lens 30 is the lens closest to the human eye 24. This embodiment is not intended to limit the disposition method of the lens in the present invention, as long as it is in the reflective polarizer 12, the first phase retarder 14, the partially penetrating part reflective element 16, the second phase retarder 18 and the linear polarizer 20 A lens is arranged on any side of at least one of them, and a total of at least three groups of lenses for focusing are included in the scope of the present application.

To further illustrate, the materials of optical components such as the reflective polarizer 12, the first phase retarder 14, the partially penetrating partial reflection element 16, the second phase retarder 18, and the linear polarizer 20 can be thin film materials or optical coatings, etc. Place on at least one of the above-mentioned lenses or at least one flat glass by means of coating, coating or bonding. For example, the reflective polarizer 12 and the partially penetrating partial reflection element 16 can be coatings on the lens, or It is a lens with a reflective polarizing function or an optical material in the form of a film attached to the lens. Therefore, the present invention can integrate the reflective polarizer 12 and the first phase retarder 14, and partially penetrate the partial reflective element 16. and the second phase retarder 18 are set as one, for example, as shown in Figure 4A, 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 single lens), for example, a reflective polarizing film is arranged on the side of the first phase retarder 14 close to the display screen 10 or a special material is used to achieve the functions of phase delay and reflective polarization of the same lens, while on the left side of the first lens group 30 , then a partially transmissive partially reflective element 16 (in this embodiment, a partially transparent partially reflective film), a second phase retarder 18 , a linear polarizer 20 and a flat glass 26 are provided in sequence. In other words, in the embodiment of FIG. 4A, the first lens 30 is disposed between the second lens 32 and the partially transmissive partially reflective element 16, the second lens 32 is disposed between the first lens 30 and the third lens 34, The third lens 34 is disposed between the second lens 32 and the reflective polarizer 12 and the first phase retarder 14 . The specific data of this embodiment are as follows Table 1 and Table 2: f = 38.5; 2ω = 90.1°; f1 = 705.1; f2 = 1573.6; f3 = 34.35; fs4 = infinite; fs5 = 38.8; TTL = 28.24 surface Curvature (Radius) thickness Nd Vd. radius lens aperture unlimited 10.00 - - 2 - 2 unlimited 0.70 1.49 57.4 twenty two - 3 unlimited 2.89 1.54 56.3 twenty two L1 4 -379.161 3.00 - - twenty two 5 -179.982 4.00 1.54 56.3 twenty three L2 6 -150.000 1.00 - - twenty three 7 150.000 5.00 1.54 56.3 twenty three L3 8 -120.000 1.65 - - twenty three 9 unlimited 0.00 - - - - Table 1. Lens parameters Aspherical Coefficient Lens Surface K A B C D. E. 4 0.000 0.000E+00 2.028E-07 4.688E-11 -1.098E-13 -3.251E-16 5 0.000 0.000E+00 -1.947E-07 -5.607E-11 5.513E-14 1.868E-16 6 0.000 0.000E+00 1.821E-07 4.786E-11 -4.971E-14 -1.545E-16 7 0.000 0.000E+00 -5.691E-08 -6.731E-12 1.300E-14 2.171E-17 8 0.000 0.000E+00 3.759E-08 1.940E-11 4.300E-14 1.574E-16 Table 2. Aspheric coefficients

，其中C=1/R，R為曲率半徑，K為圓椎係數。此外，表中L1、L2、L3分別代表第一、第二及第三透鏡，f1、f2及f3分別為第一、第二及第三透鏡的有效焦距，

為部分穿透部分反射元件反射面之焦距，

為反射式偏振片反射面之焦距，f為超短距目鏡系統之有效焦距，𝜔為超短距目鏡系統之半視場角， TTL為超短距目鏡系統之總長，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, K in Table 2 above are the parameters in the aspheric formula, and 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, and f1, f2, and f3 are the effective focal lengths of the first, second, and third lenses respectively,

is the focal length of the reflective surface of the partly penetrating partly reflective element,

is the focal length of the reflective surface of the reflective polarizer, f is the effective focal length of the ultra-short-distance eyepiece system, 𝜔 is the half-field angle of the ultra-short-distance eyepiece system, TTL is the total length of the ultra-short-distance eyepiece system, Nd is the refractive index (Refractive index), Vd is the Abbe number (Abbe number) or dispersion coefficient (V-number).

Fig. 4B shows another embodiment, the reflective polarizer 12 and the first phase retarder 14 are all arranged on the right side of the second lens 32, and partially penetrate the partial reflection element 16, the second phase retarder 18 and the linear polarization The sheets 20 are all disposed on the left side of the first lens 30 . The concrete data of this embodiment are following table three and table four: f =26.739; 2ω = 90.1°; f1 = 537.57; f2 = 41.417; f3 = 531.96; fs4 = infinite; fs5 = 48.27; TTL = 33.17 surface Curvature (Radius) thickness Nd Vd. radius lens aperture unlimited 10.00 - - 2 - 2 unlimited 0.70 1.49 57.4 20 - 3 unlimited 2.73 1.54 56.3 20 L1 4 -293.750 2.84 - - 20 5 151.088 3.89 1.54 56.3 20 L2 6 -149.296 0.85 - - 20 7 119.957 2.00 1.54 56.3 20 L3 8 203.038 10.16 - - 20 9 unlimited 0.00 - - - - Table 3. Lens parameters Aspherical Coefficient Lens Surface K A B C D. E. 4 0.000 0.000E+00 4.040E-08 6.986E-11 2.016E-13 0.000E+00 5 0.000 0.000E+00 -4.154E-08 -9.149E-11 -2.623E-13 0.000E+00 6 0.000 0.000E+00 1.687E-08 4.726E-11 1.591E-13 0.000E+00 7 0.000 0.000E+00 -3.638E-07 5.496E-11 4.674E-13 1.167E-15 8 0.000 0.000E+00 3.868E-07 -8.623E-11 -6.672E-13 0.000E+00 Table 4. Aspherical Coefficients

Fig. 4C, Fig. 4D and Fig. 4E are other three configurations of the first lens 30, the second lens 32 and the third lens 34, because the first lens 30, the second lens 32 and the third lens 34 can be single A lens or a combination of multiple lenses, and it can be a concave lens, a convex lens, etc., and the direction of the concave and convex can also be changed, so there will be many different combinations.

In the embodiment of Figure 4C, the reflective polarizer 12 and the first phase retarder 14 are arranged on the left side of the third lens 34, and the left side of the first phase retarder 14 is the second lens 32, which partially penetrates the partial reflection 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 as follows table five and table six: f =30.014; 2ω = 80°; f1 = 117.15; f2 = 156.56; f3 = -139.63; fs4 = infinite; fs5 = infinite; TTL = 32.77 surface Curvature (Radius) thickness Nd Vd. radius lens aperture unlimited 10 - - 2 - 2 unlimited 0.70 1.49 57.4 twenty one - 3 unlimited 4.00 1.54 56.3 twenty one L1 4 -64.018 4.00 - - twenty one 5 165.076 4.00 1.54 56.3 20 L2 6 -176.079 0.50 - - 20 7 unlimited 2.00 1.54 56.3 20 L3 8 76.298 7.57 - - 20 9 unlimited 0 - - - - Table 5. Lens parameters Aspherical Coefficient Lens Surface K A B C D. E. 4 0.000 0.000E+00 3.561E-07 3.243E-10 -1.281E-12 -2.554E-15 5 0.000 0.000E+00 -6.941E-07 -3.526E-10 -4.992E-13 -1.568E-15 6 0.000 0.000E+00 5.535E-07 6.616E-11 2.821E-13 2.271E-15 8 0.000 0.000E+00 -1.194E-05 0.000E+00 0.000E+00 0.000E+00 Table 6. Aspheric coefficients

In the embodiment shown in FIG. 4D , the difference from the embodiment shown in FIG. 4C is that the second phase retarder 18 and the linear polarizer 20 of this embodiment are made as independent components. The concrete data of this embodiment are following table seven and table eight: f =28.904; 2ω = 86°; f1 = 98.07; f2 = 239.815; f3 = -302.65; fs4 = 1280.8; fs5 = infinite; TTL = 36.51 surface Curvature (Radius) thickness Nd Vd. radius lens aperture unlimited 10.00 - - 2 - 2 unlimited 0.70 1.49 57.4 twenty one - 3 unlimited 1.00 - - twenty one - 4 -699.898 3.40 1.54 56.3 twenty one L1 5 -49.867 0.40 - - 20 6 129.151 2.33 1.54 56.3 20 L2 7 8875.134 0.80 - - 20 8 unlimited 2.00 1.54 56.3 20 L3 9 165.381 15.88 - - - 10 unlimited 0 - - - - Table 7. Lens parameters Aspherical Coefficient Lens Surface K A B C D. E. 4 0.000 0.000E+00 -6.686E-08 -5.374E-10 -4.884E-12 0.000E+00 5 0.000 0.000E+00 -6.212E-08 -2.810E-10 -1.050E-12 0.000E+00 6 0.000 0.000E+00 1.364E-07 4.688E-10 1.581E-12 0.000E+00 7 0.000 0.000E+00 -1.414E-07 -4.948E-10 -1.700E-12 0.000E+00 9 0.000 0.000E+00 -5.786E-07 -1.503E-09 -4.142E-12 -1.182E-14 Table 8. Aspheric coefficients

In the embodiment of Fig. 4E, the reflective polarizer 12 and the first phase retarder 14 are made into independent elements, and are arranged on the right side of the third lens 34, and partially penetrate the partial reflection element 16, the second phase retarder 18 and the line The polarizer 20 is sequentially disposed on the right side of the first lens 30 . The concrete data of this embodiment are following table nine and table ten: f =27.9923; 2ω = 90.5°; f1 = 117.79; f2 = 326.83; f3 = 99.24; fs4 = infinite; fs5 = infinite; TTL = 31.10 surface Curvature (Radius) thickness Nd Vd. radius lens aperture unlimited 10.00 - - 2 - 2 63.340 2.70 1.54 56.1 twenty two L1 3 unlimited 0.70 1.52 64.2 twenty two - 4 unlimited 2.00 - - twenty two - 5 -356.569 4.02 1.54 56.3 twenty three L2 6 -119.467 1.00 - - twenty three 7 119.397 6.00 1.54 56.3 twenty three L3 8 -97.592 0.10 - - twenty three 9 unlimited 0.33 1.52 64.2 twenty three - 10 unlimited 4.25 - - twenty three - 11 unlimited - - - - - Table 9. Lens parameters Aspherical Coefficient Lens Surface K A B C D. E. 2 0.000 0.000E+00 -1.512E-05 -4.508E-09 -7.594E-12 -2.022E-14 5 0.000 0.000E+00 1.027E-06 2.593E-11 -1.066E-15 1.197E-16 6 0.000 0.000E+00 -7.996E-07 -2.845E-11 2.541E-15 -1.153E-16 7 0.000 0.000E+00 -1.439E-07 -1.096E-11 4.045E-14 1.269E-16 8 0.000 0.000E+00 -1.782E-07 3.010E-11 -1.047E-13 -2.858E-16 Table 10. Aspherical Coefficients

To further illustrate, in the present invention, the second phase retardation film 18 and the linear polarizing film 20 can be integrated. For example, as shown in FIG. On the same side, it can be equivalent to the function of a circular polarizer.

；及 （2）

.15； 其中，f ₁為第一透鏡30之有效焦距； f ₂為第二透鏡32之有效焦距； f ₃為第三透鏡34之有效焦距； F為超短距目鏡系統之有效焦距； R ₁為第一透鏡30靠近人眼24之一側之曲率半徑； R ₂為第一透鏡30靠近顯示屏10之一側之曲率半徑； R ₃為第二透鏡32靠近人眼24之一側之曲率半徑； R ₄為第二透鏡32靠近顯示屏10之一側之曲率半徑； R ₅為第三透鏡34靠近人眼24之一側之曲率半徑；及 R ₆為第三透鏡34靠近顯示屏10之一側之曲率半徑。 The ultra-short-distance eyepiece system of the present invention can achieve a larger viewing angle, shorter system distance and good aberration correction. Please refer to Figure 4A. The ultra-short-distance eyepiece system must meet the following conditions (1) and (2): (1 )

and (2)

.15; Wherein, f ₁ is the effective focal length of the first lens 30; f ₂ is the effective focal length of the second lens 32; f ₃ is the effective focal length of the third lens 34; F is the effective focal length of the ultra-short distance eyepiece system; R ₁ is the radius of curvature of the side of the first lens 30 close to the human eye 24; R ₂ is the radius of curvature of the side of the first lens 30 close to the display screen 10; R ₃ is the radius of the side of the second lens 32 close to the human eye 24 Radius of curvature; R ₄ is the radius of curvature of the second lens 32 near the side of the display screen 10; R ₅ is the radius of curvature of the third lens 34 near the side of the human eye 24; and R ₆ is the third lens 34 near the display screen The radius of curvature of one side of 10.

； （4）

，

； （5）

；及 （6）

； 其中，

為部分穿透部分反射元件16反射面之焦距；

為反射式偏振片12反射面之焦距； TTL為超短距目鏡系統之總長；及

為超短距目鏡系統之半場視角。 Preferably, the ultra-short-distance eyepiece system of the present invention satisfies any one of the following conditions (3) to (6): (3)

;(4)

,

; (5)

and (6)

; in,

is the focal length of the reflective surface of the partially penetrating partial reflective element 16;

is the focal length of the reflection surface of the reflective polarizer 12; TTL is the total length of the ultra-short-throw eyepiece system; and

It is the half-field angle of view of the ultra-short-distance eyepiece system.

The above conditions (1), (3), and (4) can reduce the thickness of the system and have an optical magnification effect, and the condition (2) can achieve a good aberration balance and better image quality, while the conditions (5), (6) can achieve the advantages of larger viewing angle and thinner.

The present invention makes use of the principle of polarization to perform internal refraction and reflection of the optical path in the optical system to shorten the distance between the display screen and the human eye. Taking Figures 4A to 4E as examples, polarized light is emitted from the display screen 10 in the figure The optical path from the rear to the optical element in front of the human eye 24 undergoes multiple reflections, assuming that in the embodiment of Fig. 4A to Fig. 4E, the length of each reflection of the light from the display screen 10 to the optical element in front of the human eye 24 The summed optical distance is d, which is almost the same as the optical distance d from the display screen 10 to the lens 22 in the prior art of FIG. The optical path of the eye is obtained through the sum of multiple reflections, so in fact the length from the display screen 10 to the human eye will be much smaller than the length from the display screen 10 to the human eye 24 in Figure 1, so as to shorten the length of the optical system the goal of.

To sum up, the ultra-short-distance eyepiece system provided by the present invention uses multiple phase delays and reflections for light to achieve an ultra-short-distance optical structure. It can achieve good aberration performance and image quality at short distance and large field of view. Furthermore, the ultra-short-distance eyepiece system provided by the present invention can be used for the function of myopia adjustment. The imaging range is: Ф7mm～Ф52mm, suitable for screens of 0.3 inches to 3 inches, providing higher image quality for small-sized screens, and because the eyepiece system The length is shortened, so products using optical systems can achieve the purpose of thinness and miniaturization, especially suitable for wide-angle lenses or wide-angle eyepieces on head-mounted displays, game consoles and other products.

The above descriptions are only preferred embodiments of the present invention, and are 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 application of the present invention shall be included in the scope of the patent application of the present invention.

10: display screen 12: Reflective polarizer 14: The first phase retarder 16: Partially penetrating partly reflective element 18: The 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

FIG. 1 is a schematic diagram of the optical path between the display screen of the head-mounted display and human eyes in the prior art. Fig. 2 is a schematic diagram of an embodiment of the ultra-short-distance eyepiece system of the present invention. Fig. 3A to Fig. 3C are flowcharts of steps of the ultra-short-distance eyepiece system of the present invention. Fig. 4A to Fig. 4E are schematic diagrams of different configurations of the three lenses in the ultra-short-distance eyepiece system of the present invention.

10: Display screen

12: Reflective polarizer

14: The first phase retarder

16: Partially penetrating partly reflective element

18: The second phase retarder

20: linear polarizer

22: lens

24: Human eye

26: Flat glass

30: First lens

32: second lens

34: third lens

Claims (11)

An ultra-short-distance eyepiece system, comprising: a display screen, outputting images and emitting light; an optical module, comprising: a reflective polarizer, set corresponding to the display screen, receiving the light from the display screen, and making the The light partly penetrates and partly reflects; a first phase retarder is set corresponding to the reflective polarizer, and receives part of the light that penetrates the reflective polarizer, and performs the first phase delay; a part of it penetrates the partial reflective element , is set corresponding to the first phase retarder, so that the light that has been delayed by the first phase partially penetrates the part and penetrates the partial reflection element, and part of it is reflected back to the first phase retarder for the second and third times. Secondary phase retardation; a second phase retarder, set corresponding to the part of the penetrating part of the reflective element, receiving part of the light that penetrates the part of the penetrating part of the reflective element and passes through the second and third phase delays, and performs the second phase delay Four times of phase retardation; and a line of polarizers, set corresponding to the second phase retardation film, in order to allow the light that has only undergone two phase delays not to pass through and only allow the light that has undergone four phase delays to pass through; wherein, the part The light reflected back to the first phase retarder after passing through the partial reflection element passes through the first phase retarder to reach the reflective polarizer after passing through the second phase retardation of the first phase retarder, and Reflection is completed on the reflective polarizer, so that the light is reflected back to the first phase retarder to perform the third phase delay, and then the light passes through the first phase retarder and the part of the penetrating part of the reflective element to reach the second a phase retarder; and a plurality of lenses, including a first lens, a second lens and a third lens, which are respectively arranged on either side of at least one of the optical modules to guide the image output from the display screen into In at least one human eye, and the third lens is the lens closest to the display screen, and the first lens is the lens closest to the human eye; the ultra-short-distance eyepiece system satisfies the following conditions (1) and (2): ( 1) 0.4

|

+

+

|

2.6; and (2) 0.03

(

+

)+(

+

)+(

+

)

0.15; where, f ₁ is the effective focal length of the first lens; f ₂ is the effective focal length of the second lens; f ₃ is the effective focal length of the third lens; F is the effective focal length of the ultra-short-distance eyepiece system; R ₁ is the radius of curvature of the first lens on the side close to the human eye; R ₂ is the radius of curvature of the first lens on the side close to the display screen; R ₃ is the radius of the second lens on the side close to the human eye Radius of curvature; R ₄ is the radius of curvature of the second lens near the side of the display screen; R ₅ is the radius of curvature of the third lens near the side of the human eye; and R ₆ is the third lens near the display The radius of curvature of one side of the screen. The ultra-short-distance eyepiece system according to claim 1, wherein the lenses include single-piece lenses or multi-piece lenses. The ultra-short-distance eyepiece system according to claim 2, wherein the single lens is a spherical lens, an aspheric lens or a Fresnel lens. The ultra-short-distance eyepiece system as described in claim 2, wherein the multi-piece lens is made of a spherical It is composed of at least one of lens, aspheric lens and Fresnel lens. The ultra-short-distance eyepiece system described in claim 1 further satisfies any of the following conditions (3)~(6): (3)0

|

+

|

0.15; (4)0

|

|

,0

|

|

; (5)0.8

1.5; and (6) 0.7

1.3; Wherein, f _{s 4} is the focal length of the reflective surface of the partial penetrating part of the reflective element; f _{s 5} is the focal length of the reflective polarizer reflective surface; TTL is the total length of the ultra-short-distance eyepiece system; and ω is the ultra-short distance eyepiece system The half-field angle of view of the short-distance eyepiece system. The ultra-short-distance eyepiece system as claimed in item 1, wherein at least one of the reflective polarizer, the first phase retarder, the partially reflective and partially transparent element, the second phase retarder, and the linear polarizer It is a thin film material or an optical coating, and is arranged on at least one of the lenses or at least one flat glass by coating, coating or bonding. The ultra-short-distance eyepiece system as described in claim 1, wherein the first, second, third, and fourth phase delays all increase the phase delay of an odd multiple of a quarter wavelength, so that the phase delay reaching the human eye Light rays are delayed by an integer multiple of a wavelength. The ultra-short-distance eyepiece system as described in claim 1, wherein the light emitted from the display screen and entering the reflective polarizer is linearly polarized light. The ultra-short-distance eyepiece system as claimed in item 8, 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 ultra-short-distance eyepiece system as described in Claim 1, wherein the light emitted by the display screen and entering the reflective polarizer is circularly polarized light, and a third is further arranged between the display screen and the reflective polarizer a phase retarder or a circular polarizer, and the circularly polarized light passes through the third phase retarder or the Converted to linear polarized light after circular polarizer. The ultra-short-distance eyepiece system as described in Claim 1, wherein the light emitted by the display screen and entering the reflective polarizer is non-polarized light, and another line is further provided between the display screen and the reflective polarizer A polarizer is used to convert the non-polarized light into linearly polarized light after passing through the other linear polarizer.

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