Prism-type multi-fold near-eye display system and ar glasses

Abstract

A prism-type multi-fold near-eye display system and AR glasses. The system comprises a micro display screen (SCN), a light-splitting prism group (PG), a light-splitting optical flat plate (P), and a semi-transmissive and semi-reflective optical curved piece (C1), wherein the light-splitting prism group (PG) is arranged at an interval in front of the display end of the micro display screen (SCN) to form an upper-layer transverse light path; the light-splitting optical flat plate (P) is arranged below the light-splitting prism group (PG); the semi-transmissive and semi-reflective optical curved piece (C1) is arranged in front of the light-splitting optical flat plate (P); a position of human eyes is located behind the light-splitting optical flat plate (P); the light-splitting optical flat plate (P) and the semi-transmissive and semi-reflective optical curved piece (C1) form a lower-layer transverse light path; a vertical connection light path is formed from the light-emitting end of the light-splitting prism group (PG) to the upper end surface of the light-splitting optical flat plate (P); the upper-layer transverse light path, the vertical connection light path, and the lower-layer transverse light path form a display light path of an I-shaped structure from the micro display screen (SCN) to the position of human eyes. The components of the system are stacked, so that the thickness of the whole display system is less than or equal to 30 mm, the height is less than or equal to 45 mm, the field of view angle of a virtual image is greater than or equal to 60°, and the exit pupil diameter is greater than or equal to 18 mm.

Description

A prism type multiple fold return near-eye display system and AR glasses

[0001] This application claims priority to Chinese patent application 202410843094.2 filed on June 27, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of near-eye display, in particular to a prism type multiple fold return near-eye display system and AR glasses. BACKGROUND

[0003] Augmented reality glasses, namely AR glasses, can project virtual images and real world images into the human eye at the same time, allowing users to see virtual images superimposed on real scenery. AR glasses can bring great convenience to people's learning, work, life, entertainment and other aspects. When users access visual text, images and video information, they can not only move freely, but also free their hands, greatly facilitating people's daily life. AR glasses technology has developed rapidly in recent years and has been successfully applied to military equipment, industrial production, medical diagnosis and daily life entertainment and many other fields. There are already AR glasses on the market based on different optical principles such as planar semi-transparent semi-reflective, free-form surface semi-transparent semi-reflective, geometric light waveguide, catadioptric structure, and diffractive light waveguide. Among them, the catadioptric structure (commonly known as Birdbath) has been widely used due to its good optical clarity and low optical distortion.

[0004] Although the catadioptric structure has obvious advantages compared to other optical structures such as planar semi-transparent semi-reflective, it still cannot meet the needs of the development of AR glasses products. For example, Chinese patent CN112051671B discloses a near-eye display optical system that uses a conventional structure of one light splitting plane combined with one reflective curved sheet, which still has the problems of small field of view angle and low display quality. Chinese patent CN111638602B discloses an optical device and a near-eye display device that uses a structure of two light splitting planes combined with one reflective curved sheet, which reduces the overall thickness of the system, but still has the problems of small field of view angle and low display quality.

[0005] Users need AR glasses to have a larger FOV (field of view angle) and clearer images, but the FOV of the conventional single or double lens catadioptric structure is difficult to reach 50°, the clarity is difficult to match images with a resolution of 1080P or above, and the exit pupil diameter is also small, usually around 12mm.

[0006] In view of the above, the present application is proposed. SUMMARY

[0007] The prism type multiple fold return near eye display system and the AR glasses have a larger field of view angle and a clearer picture, improve the performance of the AR glasses with fold reflection structure, and solve the above technical problems in the prior art.

[0008] The purpose of the present application is realized by the following technical solutions:

[0009] A prism type multiple fold return near eye display system comprises:

[0010] A micro display screen, a light splitting prism group, a light splitting optical flat and a semi-transparent semi-reflective optical curved sheet, wherein,

[0011] The light splitting prism group is arranged in front of the display end of the micro display screen and forms an upper layer horizontal light path;

[0012] The light splitting optical flat is arranged below the light splitting prism group, a semi-transparent semi-reflective optical curved sheet is arranged in front of the light splitting optical flat, and an eye position is arranged behind the light splitting optical flat, the light splitting optical flat and the semi-transparent semi-reflective optical curved sheet form a lower layer horizontal light path;

[0013] The light splitting prism group forms a vertical connection light path from the light exit end to the upper end surface of the light splitting optical flat;

[0014] The upper layer horizontal light path, the vertical connection light path and the lower layer horizontal light path form a display light path of the I-shaped structure from the display end of the micro display screen to the eye position.

[0015] An AR glasses comprises a glasses body and a near eye display system integrated on the glasses body, and the near eye display system adopts the prism type multiple fold return near eye display system.

[0016] Compared with the prior art, the prism type multiple fold return near eye display system and the AR glasses have the following beneficial effects:

[0017] By setting the micro display screen, the light splitting prism group, the light splitting optical flat and the semi-transmissive and semi-reflective optical curved sheet, and making the micro display screen and the light splitting prism group transversely spaced apart to form an upper layer transverse light path, the light splitting optical flat and the semi-transmissive and semi-reflective optical curved sheet are arranged below to form a lower layer transverse light path, a vertical connecting light path is formed from the light exit end of the light splitting prism group to the upper end surface of the light splitting optical flat, so that the upper layer transverse light path, the vertical connecting light path and the lower layer transverse light path form a display light path of the I-shaped structure from the display end of the micro display screen to the eye position, due to the stacking arrangement of the components, the entire thickness of the near-eye display system is ≤30mm, the height is ≤45mm, while the FOV (Field of view) of the virtual image is ≥60°, and the exit pupil diameter is ≥18mm, which can well meet the requirements of small volume, large field of view and high definition of AR glasses.

[0018] BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0020] Fig. 1 is a schematic diagram of the prism type multiple return near-eye display system provided by the embodiment 1 of the present application.

[0021] Fig. 2 is a schematic diagram of the prism type multiple return near-eye display system provided by the embodiment 2 of the present application.

[0022] Fig. 3 is a schematic diagram of the prism type multiple return near-eye display system provided by the embodiment 3 of the present application.

[0023] Fig. 4 is a schematic diagram of the prism type multiple return near-eye display system provided by the embodiment 4 of the present application.

[0024] Fig. 5 is a schematic diagram of the prism type multiple return near-eye display system provided by the embodiment 5 of the present application.

[0025] Fig. 6 is a schematic diagram of the prism type multiple return near-eye display system provided by the embodiment 6 of the present application.

[0026] Fig. 7 is a schematic diagram of the prism type multiple return near-eye display system provided by the embodiment 7 of the present application.

[0027] The components corresponding to the respective marks in the figure are: SCN-micro display screen; P-polarizing optical flat; PG-polarizing prism group; PR1-first prism of the polarizing prism group; PR2-second prism of the polarizing prism group; PBS1-first polarizing beam splitter; PBS2-second polarizing beam splitter; QWP1-first quarter wave plate; QWP2-second quarter wave plate; POL1-first linear polarizer; POL2-second linear polarizer; C1-semi-transmission semi-reflection optical curved sheet; Eye-human eye position; p-polarized light; s-polarized light; c-circularly polarized light; LG1-transmissive optical lens group; L1-first optical lens of the transmissive optical lens group; LG2-total reflection optical lens group; L2-second optical lens of the total reflection optical lens group; HM1-first semi-transmission semi-reflection beam splitter; HM2-second semi-transmission semi-reflection beam splitter.

[0028] Implementation of the present application

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the specific contents of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments, which do not constitute a limitation on the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0030] The orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like are based on the orientations or positional relationships shown in the drawings, and are merely intended to facilitate the description and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present text.

[0031] The schemes provided by the present application will be described in detail below. The contents not described in detail in the embodiments of the present application belong to the prior art known to those skilled in the art. If the specific conditions are not specified in the embodiments of the present application, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used in the embodiments of the present application are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0032] As shown in FIG. 1, the embodiments of the present application provide a prism type multi-turn near-eye display system, comprising:

[0033] The micro display screen, the polarizing prism group, the polarizing optical flat and the semi-transmission semi-reflection optical curved sheet; wherein,

[0034] The display end of the micro display screen is spaced apart from the upper layer transverse light path of the split prism group;

[0035] The split optical flat is arranged below the split prism group, the front of the split optical flat is provided with a semi-transparent and semi-reflective optical curved sheet, and the rear of the split optical flat is the human eye position, and the split optical flat and the semi-transparent and semi-reflective optical curved sheet form the lower layer transverse light path;

[0036] The light emitting end of the split prism group forms a vertical connection light path with the upper end surface of the split optical flat;

[0037] The upper layer transverse light path, the vertical connection light path and the lower layer transverse light path form the I-shaped display light path from the display end of the micro display screen to the human eye position.

[0038] Preferably, in the above system, the split prism group is composed of at least two optical prisms and a split plane which is glued together, and the split plane is located on the gluing surface of the two optical prisms;

[0039] The included angle a_PP between the split plane and the split optical flat satisfies: a_PP < 20°;

[0040] The included angle a_SP1 between the micro display screen and the split plane of the split prism group satisfies: 25° < a_SP1 < 65°.

[0041] Preferably, in the above system, the included angle a_SP2 between the micro display screen and the split optical flat satisfies: 25° < a_SP2 < 65°;

[0042] The reflectivity r_CP of the semi-transparent and semi-reflective optical curved sheet satisfies: 5% < r_CP < 90%.

[0043] Preferably, in the above system, the optical prism close to the display end of the micro display screen in the split prism group is a light-transmitting optical prism;

[0044] The optical prism away from the display end of the micro display screen is coated with a total reflection film on the outside.

[0045] Further, the surface of the split plane of the split prism group is provided with a first polarization split film; or the surface of the split plane is provided with a first polarization split film and a first quarter wave plate.

[0046] Preferably, in the above system, the split optical flat adopts an optical flat with a surface coated with an optical semi-reflective and semi-transparent film; or the split optical flat adopts an optical flat with a surface pasted with a polarization split film and composed of a linear polarization module and a quarter wave plate;

[0047] The semi-transmissive and semi-reflective optical curved sheet adopts an optical plastic curved sheet with one surface coated with a semi-transmissive and semi-reflective film and the other surface coated with an anti-reflection film, and the Abbe number vd_C1 of the optical plastic curved sheet satisfies 30 < vd_C1 < 70; the surface of the optical curved sheet is any one of a spherical surface, an aspherical surface, and a free-form surface;

[0048] The micro display screen adopts any one of a Micro-OLED screen, a Micro-LED screen, an LCD screen, and an equivalent LBS light source.

[0049] Preferably, the system further comprises a light-transmissive optical lens group arranged between the display end of the micro display screen and the light-splitting prism group;

[0050] Alternatively, the system further comprises a total reflection optical lens group arranged in front of the light-splitting prism group; and the two optical prisms of the light-splitting prism group are both light-transmissive optical prisms.

[0051] Alternatively, the system further comprises a light-transmissive optical lens group and a total reflection optical lens group, the light-transmissive optical lens group is arranged between the display end of the micro display screen and the light-splitting prism group, and the total reflection optical lens group is arranged in front of the light-splitting prism group, and the two optical prisms of the light-splitting prism group are both light-transmissive optical prisms.

[0052] Preferably, in the system, the display end surface of the micro display screen is provided with a first linear polarizing film.

[0053] The upper surface of the light-splitting optical flat is sequentially provided, from top to bottom, with a second quarter-wave plate, a second polarization light-splitting film, and a second linear polarizing film.

[0054] The lower surface of the light-splitting optical flat is provided with an anti-reflection film.

[0055] Preferably, in the system, the display end surface of the micro display screen is provided with a first linear polarizing film.

[0056] When the total reflection optical lens group is arranged, a first quarter-wave plate is arranged between the light-splitting prism group and the total reflection optical lens group.

[0057] The upper surface of the light-splitting optical flat is sequentially provided, from top to bottom, with a second polarization light-splitting film and a second linear polarizing film.

[0058] The lower surface of the light-splitting optical flat is provided with an anti-reflection film.

[0059] A second quarter-wave plate is arranged between the upper surface of the light-splitting optical flat and the semi-transmissive and semi-reflective optical curved sheet.

[0060] The surface of the light-splitting plane of the light-splitting prism group is provided with a first polarization light-splitting film; or the surface of the light-splitting plane of the light-splitting prism group is provided with a first semi-reflective semi-transmissive film; or the surface of the light-splitting plane of the light-splitting prism group is provided with a first polarization light-splitting film and a first quarter-wave plate.

[0061] Preferably, in the above system, each optical lens of the light-transmitting optical lens group and the total reflection optical lens group has any one of a spherical surface, an aspherical surface and a free-form surface;

[0062] When the optical lens has an aspherical surface, the aspherical surface has a height H in a direction perpendicular to the optical axis, and different power values of the height H are H 2 , H 4 , H 6 , H 8 , H 10 , H 12 , H 14 , H 16 , a conical coefficient k and aspherical coefficients A4, A6, A8, A 10 , A 12 , A 14 and A 16 , and the aspherical surface of the optical lens is represented by the following formula:

[0063] The embodiment of the present application also provides an AR glass, comprising a glass body and a near-eye display system integrated on the glass body, wherein the near-eye display system adopts the above prism-type multi-reflection near-eye display system.

[0064] As can be seen from the above, the near-eye display system of the embodiment of the present application comprises a micro display screen, a light-splitting prism group, a light-splitting optical flat and a semi-reflective semi-transmissive optical film, the micro display screen and the light-splitting prism group are horizontally spaced apart to form an upper horizontal light path, the light-splitting optical flat and the semi-reflective semi-transmissive optical film are arranged below to form a lower horizontal light path, a vertical connecting light path is formed from the light exit end of the light-splitting prism group to the upper end surface of the light-splitting optical flat, the upper horizontal light path, the vertical connecting light path and the lower horizontal light path form a display light path in the shape of an I-beam from the display end of the micro display screen to the position of the human eye, due to the stacking of the components, the light path is effectively folded, the optical imaging modulation capability of the system is improved while the length of the light path is shortened, the entire thickness of the near-eye display system is ≤30 mm, the height is ≤45 mm, the FOV of the virtual image is ≥60°, the exit pupil diameter is ≥18 mm, and the requirements of small volume, large field of view and high definition of the AR glass are well met.

[0065] In order to more clearly show the technical solutions provided by the present application and the technical effects produced, the schemes provided by the embodiments of the present application are described in detail below with specific examples.

[0066] Embodiment 1

[0067] As shown in Fig. 1, the present embodiment provides a prism type multi-turn near-eye display system, which comprises a micro display screen SCN, a split prism group PG, a split plane FS with a split function interposed in the split prism group PG, a single split optical flat P with a split function, and a semi-transmissive and semi-reflective optical curved sheet C1 with a semi-transmissive and semi-reflective characteristic;

[0068] The split prism group PG is composed of two single plastic prisms PR1 and PR2 which are glued together and are arranged in front of the display end of the micro display screen SCN, and the micro display screen SCN and the split prism group PG form an upper horizontal light path. The arrangement here means that the two are arranged at a predetermined distance;

[0069] The split optical flat is arranged below the split prism group PG, and the light exit end of the split prism group PG forms a vertical connection light path with the upper end surface of the split optical flat P;

[0070] The semi-transmissive and semi-reflective optical curved sheet is arranged in front of the split optical flat P, and the rear of the split optical flat P is the position of the human eye, and the split optical flat P and the semi-transmissive and semi-reflective optical curved sheet form a lower horizontal light path;

[0071] The upper horizontal light path, the vertical connection light path and the lower horizontal light path form a I-shaped structure display light path from the display end of the micro display screen to the position of the human eye.

[0072] In the present embodiment, the micro display screen SCN is attached with a first linear polarization POL1 for polarization. The split plane FS of the prism glue is attached with a first polarization split film PBS1 and a first quarter wave plate QWP1 from top to bottom. The first polarization split film PBS1 is used for polarization split, and the first quarter wave plate QWP1 is used for modulating the polarization state of light. The upper side of the split optical flat P is attached with a second quarter wave plate QWP2, a second polarization split film PBS2 and a second linear polarization film POL2 from top to bottom, and the lower side of the split optical flat P is attached with an anti-reflection film ARF for reducing bottom reflection. The first polarization split film PBS1 and the second polarization split film PBS2 can transmit p-polarized light and reflect s-polarized light.

[0073] The display system, the light splitting prism group PG is composed of the first prism PR1 and the second prism PR2. The first prism PR1 is a three-prism, having two optical surfaces: the right side surface and the left lower side surface (the rest surfaces are non-optical surfaces). The right side surface of the first prism PR1 is aspherical, coated with an anti-reflective film. The left lower side surface is a plane, which is the plane that is glued to the second prism PR2. The second prism PR2 is a three-prism, having three optical surfaces: the right upper side plane, the left side surface and the lower side surface. The right upper side plane is glued to the left lower side plane of the first prism PR1 (the glue splitting plane FS); the left side surface of the second prism PR2 is aspherical, coated with a total reflection film, coaxial with the optical axis of the right side surface of the first prism PR1. The lower side surface of the second prism PR2 is aspherical, coated with an anti-reflective film; the angle between the optical axis of the lower side surface of the second prism PR2 and the optical axis of the left side surface of the second prism PR2 is 85°.

[0074] The first polarization splitting film PBS1 and the first quarter wave plate QWP1 are glued in the splitting plane FS of the first prism PR1 and the second prism PR2. The structure of the glued surface is in order from top to bottom: the first prism PR1, the first polarization splitting film PBS1, the first quarter wave plate QWP1, the second prism PR2. The splitting plane FS can be glued by optical photosensitive glue, or can be glued by OCA (Optically Clear Adhesive) optical glue or other ways.

[0075] In the display system, the inner side surface (the left side, i.e. the side close to the human eye) of the semi-transmissive semi-reflective optical curved sheet C1 is coated with a semi-reflective semi-transmissive film, and its reflectivity r_C1 = 50%. The outer side surface is coated with an anti-reflective film to reduce reflection, thereby reducing the stray light of the virtual image and improving the perspective effect. The material of the semi-transmissive semi-reflective optical curved sheet C1 is K26R. Both the inner side surface and the outer side surface are free-form surfaces.

[0076] The light splitting optical sheet P uses glass BK7 material, and the thickness t_P2 = 0.5mm.

[0077] The propagation path of the display light of the display system of the embodiment is as follows: the light emitted by the micro display screen SCN passes through the first linear polarized film POL1 and becomes p-polarized light, then passes through the first prism PR1 and the first polarized light splitting film PBS1 on the light splitting plane FS (transmits p light and reflects s light), then reaches the first quarter wave plate QWP1 on the light splitting plane FS, and becomes circularly polarized light c after conversion by the first quarter wave plate QWP1. The circularly polarized light passes through the second prism PR2 to the left, is reflected by the total reflection surface on the left side of the second prism PR2, and then passes through the second prism PR2 and the first quarter wave plate QWP1 on the light splitting plane FS again to the right. The s-polarized light is converted by the first quarter wave plate QWP1, is reflected by the first polarized light splitting film PBS1 (transmits p light and reflects s light), and then propagates downward, passes through the second quarter wave plate QWP2 for the third time, is converted into circularly polarized light c, passes through the lower surface of the second prism PR2, and then propagates downward to the light splitting optical flat P. The circularly polarized light first passes through the second quarter wave plate QWP2 on the light splitting optical flat P, is converted into s light, is reflected by the second polarized light splitting film PBS2 (transmits p light and reflects s light), and then propagates to the right, passes through the second quarter wave plate QWP2 again, is converted into circularly polarized light c, and then continues to propagate to the right and is incident on the half-transmission half-reflection film in the half-transmission half-reflection optical curved plate C1. Part of the light directly passes through the half-transmission half-reflection optical curved plate to the outside of the module, and the other part is reflected to the left and still retains circular polarization. The circularly polarized light passes through the second quarter wave plate QWP2 again, is converted into p-polarized light, then passes through the second polarized light splitting film PBS2 (transmits s light and reflects p light) and the light splitting optical flat P, and finally reaches the human eye.

[0078] In the embodiment, the polarized light splitting film and the corresponding wave plate are attached to the light splitting plane, so that the system assembly difficulty is greatly reduced while the optical function of the system is ensured, and the production process is facilitated.

[0079] Embodiment 2

[0080] As shown in FIG. 2, the embodiment of the present application provides a prism type multiple-turn near-eye display system, which comprises:

[0081] The micro display screen SCN, the light-transmitting optical lens group LG1, the total reflection optical lens group LG2, the light-splitting prism group PG, the light-splitting prism group PG, the light-splitting optical flat P, and the half-transmission half-reflection optical curved plate C1.

[0082] The light-transmitting optical lens group LG1 and the total reflection optical lens group LG2 are sequentially and spaced apart from each other in front of the display end of the micro display screen SCN, and form an upper layer horizontal light path.

[0083] The light-splitting optical flat is arranged below the light-transmitting optical lens group LG1, and the light-emitting end of the light-transmitting optical lens group LG1 forms a vertical connecting light path with the upper end surface of the light-splitting optical flat P;

[0084] A semi-transmissive and semi-reflective optical curved sheet C1 is arranged in front of the light-splitting optical flat P, and the rear of the light-splitting optical flat P is the human eye position, and the light-splitting optical flat P and the semi-transmissive and semi-reflective optical curved sheet C1 form a lower horizontal light path;

[0085] The upper horizontal light path, the vertical connecting light path and the lower horizontal light path form a I-shaped display light path of the display end of the micro display screen to the human eye position.

[0086] The light-splitting prism group PG is composed of the first prism PR1, the second prism PR2 and a light-splitting flat FS with light-splitting function, and the light-splitting flat FS with light-splitting function is located on the bonding surface. In the display system, the light emitted by the micro display screen SCN passes through the light-transmitting optical lens group LG1, the first prism PR1, the light-splitting flat FS, the second prism PR2 and the total reflection optical lens group LG2 in sequence, and then is reflected by the reflecting surface of the total reflection optical lens group LG2 to propagate to the right (with reference to up, down, left and right in FIG. 2), re-passes through the total reflection optical lens group LG2 and the second prism PR2, reaches the light-splitting flat FS again and is reflected on the surface of the light-splitting flat FS, at this time the light propagates downward, passes through the second prism PR2 for the third time and reaches the light-splitting optical flat P downward, is reflected on the surface of the light-splitting optical flat P, at this time the light propagates to the right. When the light reaches the semi-transmissive and semi-reflective optical curved sheet C1, it is reflected again, propagates to the left and passes through the light-splitting optical flat P to finally reach the human eye position Eye. The optical system containing the above basic structure and similar propagation path is within the protection scope of the present application.

[0087] In the display system, the light-splitting flat FS, the light-splitting optical flat P and the semi-transmissive and semi-reflective optical curved sheet C1 all have light-splitting characteristics, the light-splitting characteristics can be realized by coating an optical semi-reflective and semi-transmissive film on the surface of these optical elements, or by pasting a polarization light-splitting film on the surface of the elements and inserting a polarization mode and a quarter-wave plate in the optical system to change the polarization state and direction of the light to realize the switching of transmission and reflection. Both of the above two ways are within the protection scope of the present application.

[0088] The micro display screen SCN in the display system can be a micro-sized organic light-emitting diode (Micro-OLED) screen, a micro-sized light-emitting diode (Micro-LED) screen, a LCD (Liquid crystal Display) screen with appropriate size, or an LBS (Laser beam scanning) light source equivalent to the micro display screen.

[0089] The material of the light-splitting optical flat plate P in the display system can be optical plastic or glass, and the thickness t_P satisfies 0.1 mm < t_P2 < 2.0 mm. Any one side of the light-splitting optical flat plate needs to be provided with the semi-transmissive and semi-reflective film or the polarization light-splitting film mentioned above, and the other side can be coated with an anti-reflection film to increase the transmittance.

[0090] The light-transmitting optical lens group LG1 in the display system can be provided or cancelled, and the number of lenses Ln satisfies 0 ≤ Ln ≤ 5. The lenses can be non-cemented lenses, double-cemented lenses or triple-cemented lenses (when calculating the total number of lenses in the lens group, double-cemented lenses are counted as two pieces, and triple-cemented lenses are counted as three pieces). The material of the lenses can be glass lenses, plastic lenses or a combination of the two. When the lens group contains cemented lenses, the material can be a combination of double-color injection molding plastic, glass cementing or glass-plastic hybrid. Each surface of all the lenses is coated with an anti-reflection film to reduce stray light of the optical system.

[0091] The total number of lenses Ln in the total reflection optical lens group LG2 satisfies 0 ≤ Ln ≤ 5. The lenses can be non-cemented lenses, double-cemented lenses or triple-cemented lenses (when calculating the total number of lenses in the lens group, double-cemented lenses are counted as two pieces, and triple-cemented lenses are counted as three pieces). The material of the lenses can be glass lenses, plastic lenses or a combination of the two. When the lens group contains cemented lenses, the material can be a combination of double-color injection molding plastic, glass cementing or glass-plastic hybrid. One of the surfaces of the leftmost lens (the lens close to the position of the human eye) of the total reflection optical lens group LG2 is coated with a total reflection film to reflect the light path, and each surface of all the remaining lenses (when the number of lenses is greater than or equal to 2) is coated with an anti-reflection film to reduce stray light of the optical system.

[0092] The display system comprises a light-splitting prism group PG (Prism group) composed of at least two optical prisms (PR1, PR2). The two prisms are combined by gluing (or other means) and the light-splitting plane FS is located on the gluing surface of the first optical prism PR1 and the second optical prism PR2. The first optical prism PR1 or the second optical prism PR2 can be a single prism or a glued prism composed of a general lens and a prism or a prism and a prism. The material of the prism or the lens can be glass or plastic. When the prism is a glued prism, the material can be a combination of double-color injection molding plastic, glass gluing, or glass-plastic mixing. When the total reflection optical lens group LG2 is not provided, the leftmost optical surface of the second prism PR2 is coated with a total reflection film, and the other optical surfaces of the light-splitting prism group are coated with an anti-reflection film to reduce stray light of the optical system. When the total reflection optical lens group LG2 is provided, the optical surfaces of the light-splitting prism group can be coated with an anti-reflection film.

[0093] A quarter-wave plate can be inserted on the gluing surface of the light-splitting prism group (i.e. near the light-splitting plane FS) to adjust the polarization state of the returned light. Whether the quarter-wave plate is included is within the protection scope of the present application.

[0094] A quarter-wave plate can be inserted in the total reflection optical lens group LG2 to adjust the polarization state of the returned light. Whether the quarter-wave plate is included is within the protection scope of the present application.

[0095] A quarter-wave plate can be inserted on the left side of the curved sheet C1 to adjust the polarization state of the returned light. Whether the quarter-wave plate is included is within the protection scope of the present application.

[0096] Each lens surface in the light-transmitting optical lens group LG1, the total reflection optical lens group LG2, and the light-splitting prism group PG can be spherical, aspherical, or free-form. When the surface is aspherical, the aspherical surface has a height H in the optical axis direction Z and a height H in the direction perpendicular to the optical axis. The different power values of the height H are H 2 , H 4 , H 6 , H 8 , H 10 , H 12 , H 14 , H 16 The base radius of the aspherical surface is R, the conical coefficient k, and the aspherical coefficients are A4, A6, A8, A 10 , A 12 , A 14 , and A 16 . The aspherical surface of the lens surface is represented by the following formula:

[0097] In this display system, the inner surface (left side in Figure 1) of the semi-reflective optical curved plate C1 is coated with a semi-reflective film, and its reflectivity r_C1 satisfies 5% < r_CP < 90%. The outer surface is coated with an anti-reflection film to reduce reflection, thereby reducing stray light in the virtual image and improving the perspective effect. The inner and outer coating methods can be interchanged, and both methods are within the scope of protection of this application. The material of the curved plate is optical plastic, and its Abbe number vd_C1 satisfies: 30 < vd_C1 < 70.

[0098] The surface of the semi-transparent, semi-reflective optical lens C1 can be spherical, aspherical, or freeform. When the surface is aspherical, the surface shape formula is the same as that of a lens. When the surface is freeform, the surface shape needs to be fitted by polynomials in both the x and y directions. Freeform prisms can reduce system distortion, but they require more sophisticated manufacturing processes and have higher production costs.

[0099] The light paths in this display system form an "I"-shaped structure. The angle a_PP between the beam-splitting plane FS and the beam-splitting optical plate P satisfies <a_PP < 20°. The angle a_SP1 between the microdisplay SCN and the beam-splitting plane FS satisfies: 25° <a_SP1 < 65°. The angle a_SP2 between the microdisplay SCN and the beam-splitting optical plate P satisfies: 25° <a_SP2 < 65°.

[0100] The system can be designed to ensure that the thickness of the entire display system is ≤30mm and the height is ≤45mm, while achieving a field of view (FOV) of ≥60° for the virtual image and an exit pupil diameter of ≥18mm.

[0101] Example 3

[0102] As shown in Figure 3, this embodiment of the invention provides a prism-type multiple reflection near-eye display system. In this system, the light-transmitting optical lens group LG1 uses a single plastic lens, namely the first optical lens L1; the total reflection optical lens group LG2 uses a single plastic lens, namely the second optical lens L2; ​​and the beam-splitting prism group PG is composed of two single plastic prisms, namely the first prism PR1 and the second prism PR2, and the beam-splitting plane FS bonded together.

[0103] The micro-display SCN has a translucent optical lens group LG1 and a total internal reflection optical lens group LG2 arranged sequentially at intervals in front of the display end to form the upper horizontal optical path;

[0104] The beam-splitting optical plate is positioned below the light-transmitting optical lens group LG1, and a vertical connecting optical path is formed between the light-emitting end of the light-transmitting optical lens group LG1 and the upper surface of the beam-splitting optical plate P.

[0105] A half-transmission half-reflection optical film C1 is arranged in front of the light splitting optical flat P, and the rear of the light splitting optical flat P is the position of the human eye. The light splitting optical flat P and the half-transmission half-reflection optical film C1 form a lower horizontal light path.

[0106] The upper horizontal light path, the vertical connecting light path and the lower horizontal light path form a I-shaped structure display light path from the display end of the micro display screen to the position of the human eye.

[0107] In the embodiment, the micro display screen SCN is pasted with a first linear polarization film POL1 for polarization. The light splitting plane FS of the prism is pasted with a first polarization light splitting film PBS1 and a first quarter wave plate QWP1 from top to bottom. The first polarization light splitting film PBS1 is used for polarization splitting, and the first quarter wave plate QWP1 is used for modulating the polarization state of light. The upper side of the light splitting optical flat P is pasted with a second quarter wave plate QWP2, a second polarization light splitting film PBS2 and a second linear polarization film POL2 from top to bottom, and the lower side of the light splitting optical flat P is pasted with an anti-reflection film ARF for reducing bottom reflection. The first polarization light splitting film PBS1 and the second polarization light splitting film PBS2 can transmit p-polarized light and reflect s-polarized light.

[0108] In the display system, the first optical lens L1 is coated with an anti-reflection film on both sides. The first optical lens L1 has a positive refractive power. A lower refractive index optical plastic material K26R is used. Both optical surfaces of the first optical lens L1 are optical aspheric surfaces.

[0109] In the display system, the left side (close to the eye side) of the second optical lens L2 is coated with a total reflection film. The second optical lens L2 uses a higher refractive index optical plastic material OKP1. The right side transmission optical surface of the second optical lens L2 is coated with an anti-reflection film.

[0110] In the display system, the light splitting prism group PG is composed of a first prism PR1 and a second prism PR2. The first prism PR1 is a three-prism with two optical surfaces: the right side and the lower left side (the remaining surfaces are non-optical surfaces). The right side of the first prism PR1 is an aspheric surface coaxial with the optical axis of the first optical lens L1. The lower left side is a plane, which is the plane for gluing with the second prism PR2. The second prism PR2 is a three-prism with three optical surfaces: the upper right plane, the left side and the lower side. The upper right plane is glued with the lower left plane of the first prism PR1 (gluing plane FS); the left side of the second prism PR2 is an aspheric surface coated with an anti-reflection film, coaxial with the optical axes of the first optical lens L1 and the second optical lens L2. The lower side of the second prism PR2 is an aspheric surface coated with an anti-reflection film; the optical axis of the lower side of the second prism PR2 is at an angle of 85° with the optical axis of the left side of the second prism PR2.

[0111] The first polarization beam splitting film PBS1 and the first quarter wave plate QWP1 are sandwiched in the splitting plane FS of the first prism PR1 and the second prism PR2. The structure of the splitting plane FS from top to bottom is the first prism PR1, the first polarization beam splitting film PBS1, the first quarter wave plate QWP1, and the second prism PR2. The splitting plane FS can be bonded by optical photosensitive adhesive, OCA (Optically Clear Adhesive), or other methods.

[0112] In the display system, the inner side (left side, i.e., the side close to the human eye) of the semi-transmissive and semi-reflective optical curved sheet C1 is coated with a semi-reflective and semi-transmissive film, and the reflectivity r_C1 is 50%. The outer side is coated with an anti-reflection film to reduce reflection, thereby reducing stray light of the virtual image and improving the see-through effect. The material of the semi-transmissive and semi-reflective optical curved sheet is K26R. Both the inner side and the outer side are free-form surfaces.

[0113] The splitting optical flat P is made of glass BK7 material, and the thickness t_P2 is 0.5 mm.

[0114] The propagation path of the display light of the display system of the embodiment is as follows: the light emitted by the micro display screen SCN passes through the first linear polarization film POL1 and becomes p-polarized light, then passes through the first optical lens L1, the first prism PR1, and the first polarization beam splitting film PBS1 on the splitting plane FS (transmits p-polarized light and reflects s-polarized light), then reaches the first quarter wave plate QWP1 on the splitting plane FS, and is converted into circularly polarized light c by the first quarter wave plate QWP1. The circularly polarized light passes through the second prism PR2 and the second optical lens L2 from left to right, is reflected by the total reflection surface on the left side of the second optical lens L2, then passes through the second optical lens L2 and the second prism PR2 from right to left again, and is converted into s-polarized light by the first quarter wave plate QWP1. The s-polarized light is incident on the first polarization beam splitting film PBS1 and is reflected downward after being reflected by the first polarization beam splitting film PBS1 (transmits p-polarized light and reflects s-polarized light), then passes through the second quarter wave plate QWP2 for the third time, is converted into circularly polarized light c, then passes through the lower side of the second prism PR2 and is transmitted downward to the splitting optical flat P. The circularly polarized light first passes through the second quarter wave plate QWP2 on the splitting optical flat P, is converted into s-polarized light, then is incident on the second polarization beam splitting film PBS2 (transmits p-polarized light and reflects s-polarized light) and is reflected to the right, then passes through the second quarter wave plate QWP2 again, is converted into circularly polarized light c, and continues to be transmitted to the right and is incident on the semi-reflective and semi-transmissive film on the inner side of the semi-transmissive and semi-reflective optical curved sheet C1. Part of the light directly passes through the semi-transmissive and semi-reflective optical curved sheet to the outside of the module, and the other part is reflected to the left and still retains circular polarization. The circularly polarized light passes through the second quarter wave plate QWP2 again, is converted into p-polarized light, then passes through the second polarization beam splitting film PBS2 (transmits s-polarized light and reflects p-polarized light) and the splitting optical flat P, and finally reaches the human eye.

[0115] Compared with the system structure of Embodiment 1, the system structure is simplified, and the system structure is more compact.

[0116] Embodiment 4

[0117] As shown in FIG. 4, the embodiment of the application provides a prism type multiple-turn near-eye display system, in which a light-transmitting optical lens group LG1 uses a plastic lens, i.e., a first optical lens L1, and a total reflection optical lens group LG2 is not arranged, and a splitting prism group PG is composed of two single plastic prisms, i.e., a first prism PR1 and a second prism PR2, and a splitting plane FS.

[0118] The light-transmitting optical lens group LG1 is arranged in front of a display end of the micro display screen SCN to form an upper horizontal light path.

[0119] A splitting optical flat plate is arranged below the light-transmitting optical lens group LG1, and a light exit end of the light-transmitting optical lens group LG1 forms a vertical connecting light path with an upper end surface of the splitting optical flat plate P.

[0120] A semi-transmissive and semi-reflective optical curved plate C1 is arranged in front of the splitting optical flat plate P, and a human eye position is arranged behind the splitting optical flat plate P, and the splitting optical flat plate P and the semi-transmissive and semi-reflective optical curved plate C1 form a lower horizontal light path.

[0121] The upper horizontal light path, the vertical connecting light path and the lower horizontal light path form a I-shaped structure display light path from the display end of the micro display screen to the human eye position.

[0122] In the embodiment, the micro display screen SCN is attached with a first linear polarization film POL1 for polarization. The splitting plane FS of the prism is attached with a first polarization splitting film PBS1 and a first quarter wave plate QWP1 from top to bottom. The first polarization splitting film PBS1 is used for polarization splitting, and the first quarter wave plate QWP1 is used for modulating the polarization state of light. The upper side of the splitting optical flat plate P is attached with a second quarter wave plate QWP2, a second polarization splitting film PBS2 and a second linear polarization film POL2 from top to bottom, and the lower side of the splitting optical flat plate P is attached with an anti-reflection film ARF for reducing bottom reflection. The first polarization splitting film PBS1 and the second polarization splitting film PBS2 can transmit p-polarized light and reflect s-polarized light.

[0123] In the display system, the first optical lens L1 is coated with an anti-reflection film on both sides. The first optical lens L1 has a positive refractive power. A low refractive index optical plastic material K26R is used. Both optical surfaces of the first optical lens L1 are optical aspheric surfaces.

[0124] The display system, the light splitting prism group PG is composed of a first prism PR1 and a second prism PR2. The first prism PR1 is a three-prism, having two optical surfaces: the right side surface and the left lower side surface (the rest of the surfaces are non-optical surfaces). The right side surface of the first prism PR1 is an aspherical surface, coaxial with the optical axis of the first optical lens L1. The left lower side surface is a plane, which is the plane that is glued to the second prism PR2. The second prism PR2 is a three-prism, having three optical surfaces: the right upper side plane, the left side surface and the lower side surface. The right upper side plane is glued to the left lower side plane of the first prism PR1 (the gluing plane FS); the left side surface of the second prism PR2 is an aspherical surface, coated with a total reflection film, coaxial with the optical axis of the first optical lens L1. The lower side surface of the second prism PR2 is an aspherical surface, coated with an anti-reflection film; the angle between the optical axis of the lower side surface of the second prism PR2 and the optical axis of the left side surface of the second prism PR2 is 85°.

[0125] The first polarization splitting film PBS1 and the first quarter-wave plate QWP1 are inserted into the light splitting plane FS where the first prism PR1 is glued to the second prism PR2. The structure of the gluing surface from top to bottom is: the first prism PR1, the first polarization splitting film PBS1, the first quarter-wave plate QWP1, the second prism PR2. The light splitting plane FS can be glued by optical photosensitive glue, or can be glued by OCA (Optically Clear Adhesive) optical glue or other ways.

[0126] In the display system, the inner side surface (the left side, i.e. the side close to the human eye) of the semi-transmissive semi-reflective optical curved sheet C1 is coated with a semi-reflective semi-transmissive film, with a reflectivity r_C1 = 50%. The outer side surface is coated with an anti-reflection film to reduce reflection, thereby reducing the stray light of the virtual image and improving the perspective effect. The material of the semi-transmissive semi-reflective optical curved sheet is K26R. Both the inner side surface and the outer side surface are free-form surfaces.

[0127] The light splitting optical sheet P is made of glass BK7 material, with a thickness t_P2 = 0.5mm.

[0128] The propagation path of the display light of the display system of the embodiment is as follows: the light emitted by the micro display screen SCN passes through the first linear polarizing film POL1 and becomes p-polarized light, then passes through the first optical lens L1, the first prism PR1 and the first polarizing beam splitter film PBS1 on the light splitting plane FS (transmits p-polarized light and reflects s-polarized light), then reaches the first quarter wave plate QWP1 on the FS, and is converted into circularly polarized light c by the first quarter wave plate QWP1. The circularly polarized light passes through the second prism PR2 to the left, is reflected by the total reflection surface on the left side of the second prism PR2, and then passes through the second prism PR2 and the first quarter wave plate QWP1 on the light splitting plane FS again to the right. The s-polarized light is converted into p-polarized light by the first quarter wave plate QWP1, is incident on the first polarizing beam splitter film PBS1, is reflected by the first polarizing beam splitter film PBS1 (transmits p-polarized light and reflects s-polarized light), and then passes downward. The p-polarized light passes through the second quarter wave plate QWP2 for the third time, is converted into circularly polarized light c, passes through the lower surface of the second prism PR2, and then passes downward to the light splitting optical flat P. The circularly polarized light first passes through the second quarter wave plate QWP2 on the light splitting optical flat P, is converted into s-polarized light, is then incident on the second polarizing beam splitter film PBS2 (transmits p-polarized light and reflects s-polarized light), is reflected to the right, passes through the second quarter wave plate QWP2 again, is converted into circularly polarized light c, and then continues to pass rightward to be incident on the semi-transparent semi-reflective film in the inner surface of the semi-transparent semi-reflective optical curved plate C1. Part of the light directly passes through the semi-transparent semi-reflective optical curved plate to the outside of the module, and the other part is reflected to the left and still retains circular polarization. The circularly polarized light passes through the second quarter wave plate QWP2 again, is converted into p-polarized light, and then passes through the second polarizing beam splitter film PBS2 (transmits s-polarized light and reflects p-polarized light) and the light splitting optical flat P to reach the human eye.

[0129] The system structure of the embodiment is further simplified, and the system structure is more compact.

[0130] Embodiment 5

[0131] As shown in FIG. 5, the embodiment of the present application provides a prism type multiple-turn return near-eye display system. In the system, the light-transmitting optical lens group LG1 uses a plastic lens, i.e., the first optical lens L1, the total reflection optical lens group LG2 uses a plastic lens, i.e., the second optical lens L2, and the light-splitting prism group PG is composed of two single plastic prisms, i.e., the first prism PR1 and the second prism PR2, and the light splitting plane FS.

[0132] The light-transmitting optical lens group LG1 and the total reflection optical lens group LG2 are sequentially and spaced apart from each other in front of the display end of the micro display screen SCN, and form an upper layer horizontal light path.

[0133] The light splitting optical flat is arranged below the light-transmitting optical lens group LG1, and a vertical connecting light path is formed between the light exit end of the light-transmitting optical lens group LG1 and the upper surface of the light splitting optical flat P.

[0134] A half-transmission half-reflection optical curved sheet C1 is arranged in front of the light-splitting optical flat P, and the position of the human eye is behind the light-splitting optical flat P, and the light-splitting optical flat P and the half-transmission half-reflection optical curved sheet C1 form a lower horizontal light path;

[0135] The upper horizontal light path, the vertical connecting light path and the lower horizontal light path form a I-shaped display light path of the display end of the micro display screen to the position of the human eye.

[0136] In the embodiment, the micro display screen SCN is pasted with a first linear polarization POL1 for polarization. The light-splitting plane FS of the prism is pasted with a first polarization light-splitting film PBS1 for polarization light splitting. The upper side of the light-splitting optical flat P is sequentially pasted with a second polarization light-splitting film PBS2 and a second linear polarization film POL2 from top to bottom, and the lower side of the light-splitting optical flat P is pasted with an anti-reflection film ARF for reducing bottom reflection. The first polarization light-splitting film PBS1 and the second polarization light-splitting film PBS2 can transmit p-polarized light and reflect s-polarized light.

[0137] In the display system, the first optical lens L1 is coated with an anti-reflection film on both sides. The first optical lens L1 has a positive refractive power. A lower refractive index optical plastic material K26R is used. Both optical surfaces of the first optical lens L1 are optical aspheric surfaces.

[0138] In the display system, the left side (close to the eye side) of the second optical lens L2 is coated with a total reflection film. The second optical lens L2 uses a higher refractive index optical plastic material OKP1. The right side transmission optical surface of the second optical lens L2 is coated with an anti-reflection film.

[0139] In the display system, the light-splitting prism group PG is composed of a first prism PR1, a second prism PR2 and a light-splitting plane FS. The first prism PR1 is a three-prism with two optical surfaces: the right side surface and the lower left side surface (the remaining surfaces are non-optical surfaces). The right side surface of the first prism PR1 is an aspheric surface coaxial with the optical axis of the first optical lens L1. The lower left side surface is a plane, which is the plane for gluing with the second prism PR2. The second prism PR2 is a three-prism with three optical surfaces: the upper right side plane, the left side surface and the lower side surface. The upper right side plane is glued with the lower left side plane of the first prism PR1 (the gluing plane FS); the left side surface of the second prism PR2 is an aspheric surface coated with an anti-reflection film, coaxial with the optical axes of the first optical lens L1 and the second optical lens L2. The lower side surface of the second prism PR2 is an aspheric surface coated with an anti-reflection film; the optical axis of the lower side surface of the second prism PR2 is at an angle of 85° with the optical axis of the left side surface of the second prism PR2.

[0140] The first polarization beam splitting film PBS1 is sandwiched in the splitting plane FS between the first prism PR1 and the second prism PR2. The structure of the bonding surface is in order from top to bottom: the first prism PR1, the first polarization beam splitting film PBS1, and the second prism PR2. The splitting plane FS can be bonded by optical photosensitive glue, OCA (Optically Clear Adhesive) optical glue, or other ways.

[0141] In the display system, the first quarter wave plate QWP1 is arranged between the right side of the second optical lens L2 and the second prism PR2, and the first quarter wave plate QWP1 can also be attached to the optical surface on the right side of the second optical lens L2.

[0142] In the display system, the inner side (left side, i.e., the side close to the human eye) of the semi-transmissive and semi-reflective optical curve sheet C1 is coated with a semi-reflective and semi-transmissive film, and the reflectivity r_C1 is 50%. The outer side is coated with an anti-reflection film to reduce reflection, thereby reducing stray light of the virtual image and improving the see-through effect. The material of the semi-transmissive and semi-reflective optical curve sheet is K26R. Both the inner side and the outer side are free-form surfaces.

[0143] In the display system, the second quarter wave plate QWP2 is arranged between the left side of the semi-transmissive and semi-reflective optical curve sheet C1 and the splitting optical plate P, and the second quarter wave plate QWP2 can also be attached to the reflective surface on the left side of the semi-transmissive and semi-reflective optical curve sheet C1.

[0144] The splitting optical plate P uses glass BK7 material, and the thickness t_P2 is 0.5 mm.

[0145] The propagation path of the display light of the display system of the embodiment is as follows: the light emitted by the micro display screen SCN passes through the first linear polarizing film POL1 and becomes p-polarized light, then passes through the first optical lens L1, the first prism PR1, the first polarizing beam splitter film PBS1 on the splitting plane FS (transmits p-polarized light and reflects s-polarized light), the second prism PR2, and then reaches the first quarter wave plate QWP1, and is converted into circularly polarized light c by the first quarter wave plate QWP1. The circularly polarized light passes through the second optical lens L2 to the left, is reflected by the total reflection surface on the left side of the second optical lens L2, and then passes through the second optical lens L2 to the right to reach the QWP1, and is converted into s-polarized light by the first quarter wave plate QWP1. The s-polarized light passes through the second prism PR2 to the right, is reflected by the first polarizing beam splitter film PBS1 on the splitting plane FS of the cemented surface, and is kept in the s-polarized state to propagate downward, then passes through the lower side of the second prism PR2 and propagates downward to reach the light splitting optical flat P. The s-polarized light is reflected by the second polarizing beam splitter film PBS2 (transmits p-polarized light and reflects s-polarized light) on the light splitting optical flat P and propagates to the right, then reaches the second quarter wave plate QWP2, is converted into circularly polarized light c, and continues to propagate to the right to be incident on the semi-transparent semi-reflective film in the semi-transparent semi-reflective optical curved plate C1. Part of the light directly passes through the semi-transparent semi-reflective optical curved plate C1 to the outside of the module, and the other part is reflected to the left and still keeps the circular polarization. The circularly polarized light passes through the second quarter wave plate QWP2 again, is converted into p-polarized light, then passes through the second polarizing beam splitter film PBS2 (transmits s-polarized light and reflects p-polarized light) and the light splitting optical flat P, and reaches the human eye.

[0146] The embodiment has excellent optical modulation capability, thereby having excellent optical imaging quality.

[0147] Embodiment 6

[0148] As shown in FIG. 6, the embodiment of the present application provides a prism type multiple-turn-return near-eye display system. In the system, the light-transmitting optical lens group LG1 is not arranged, the total reflection optical lens group LG2 uses one piece of plastic lens, i.e., the second optical lens L2, and the light-splitting prism group PG is composed of two single plastic prisms, i.e., the first prism PR1 and the second prism PR2, and the splitting plane FS is cemented.

[0149] The light-transmitting optical lens group LG1 and the total reflection optical lens group LG2 are sequentially and spaced apart from each other in front of the display end of the micro display screen SCN, and form an upper horizontal light path.

[0150] The light splitting optical flat is arranged below the light-transmitting optical lens group LG1, and the light exit end of the light-transmitting optical lens group LG1 forms a vertical connecting light path with the upper end surface of the light splitting optical flat P.

[0151] A semi-transmissive and semi-reflective optical curved sheet C1 is arranged in front of the light-splitting optical flat P, and the rear of the light-splitting optical flat P is the position of the human eye, and the light-splitting optical flat P and the semi-transmissive and semi-reflective optical curved sheet C1 form a lower horizontal light path.

[0152] The upper horizontal light path, the vertical connecting light path and the lower horizontal light path form a I-shaped structure display light path from the display end of the micro display screen to the position of the human eye.

[0153] In the embodiment, the micro display screen SCN is attached with a first linear polarization POL1 for polarization. The light-splitting plane FS of the prism is attached with a first polarization light-splitting film PBS1 for polarization light-splitting. The upper side of the light-splitting optical flat P is sequentially attached with a second polarization light-splitting film PBS2 and a second linear polarization film POL2 from top to bottom, and the lower side of the light-splitting optical flat P is attached with an anti-reflection film ARF for reducing bottom reflection. The first polarization light-splitting film PBS1 and the second polarization light-splitting film PBS2 can transmit p-polarized light and reflect s-polarized light.

[0154] In the display system, the left side (close to the eye side) of the second optical lens L2 is coated with a total reflection film. The second optical lens L2 is made of an optical plastic material OKP1 with a relatively high refractive index. The right side of the second optical lens L2 is coated with an anti-reflection film.

[0155] In the display system, the light-splitting prism group PG is composed of a first prism PR1, a second prism PR2 and a light-splitting plane FS. The first prism PR1 is a three-prism with two optical surfaces: the right side and the lower left side (the remaining surfaces are non-optical surfaces). The right side of the first prism PR1 is a non-spherical surface coated with an anti-reflection film. The lower left side is a plane which is the plane for gluing with the second prism PR2. The second prism PR2 is a three-prism with three optical surfaces: the upper right plane, the left side and the lower side. The upper right plane is glued with the lower left plane of the first prism PR1 (the light-splitting plane FS); the left side of the second prism PR2 is a non-spherical surface coated with an anti-reflection film, coaxial with the optical axis of the second optical lens L2. The lower side of the second prism PR2 is a non-spherical surface coated with an anti-reflection film; the angle between the optical axis of the lower side of the second prism PR2 and the optical axis of the left side of the second prism PR2 is 85°.

[0156] The first polarization light-splitting film PBS1 is inserted into the light-splitting plane FS where the first prism PR1 is glued with the second prism PR2, and the structure of the glued surface is sequentially the first prism PR1, the first polarization light-splitting film PBS1 and the second prism PR2 from top to bottom. The light-splitting plane FS can be glued by optical photosensitive glue, or can be glued by OCA (Optically Clear Adhesive) optical glue or other ways.

[0157] In the display system, a first quarter wave plate QWP1 is arranged between the right side of the second optical lens L2 and the second prism PR2 (the first quarter wave plate QWP1 can also be attached to the optical surface on the right side of L2).

[0158] In the display system, the inner side (the left side, i.e., the side close to the human eye) of the semi-transmissive and semi-reflective optical curved sheet C1 is coated with a semi-reflective and semi-transmissive film, and the reflectivity r_C1 thereof is 50%. The outer side is coated with an anti-reflection film to reduce reflection, thereby reducing stray light of the virtual image and improving the see-through effect. The material of the semi-transmissive and semi-reflective optical curved sheet is K26R. Both the inner side and the outer side are free-form surfaces.

[0159] In the display system, a quarter wave plate QWP2 is arranged between the left side of the semi-transmissive and semi-reflective optical curved sheet C1 and the light splitting optical flat P, and the QWP2 can also be attached to the reflective surface on the left side of the semi-transmissive and semi-reflective optical curved sheet C1.

[0160] The light splitting optical flat P is made of glass BK7 material, and the thickness t_P2 is 0.5 mm.

[0161] The propagation path of the display light in the display system of the embodiment is as follows: the light emitted by the micro display screen SCN passes through the first linear polarizing film POL1 and becomes p-polarized light, and then passes through the first prism PR1, the first polarizing beam splitter film PBS1 on the light splitting flat FS (transmits p-polarized light and reflects s-polarized light), the second prism PR2, and then reaches the first quarter wave plate QWP1. After conversion by the first quarter wave plate QWP1, the light becomes circularly polarized light c. The circularly polarized light passes through the second light splitting flat L2 to the left, is reflected by the total reflection surface on the left side of the second light splitting flat L2, and then passes through the second light splitting flat L2 to the right to reach the first quarter wave plate QWP1. The s-polarized light is converted by the first quarter wave plate QWP1, passes through the second prism PR2 to the right, and is incident on the first polarizing beam splitter film PBS1 on the bonded light splitting flat FS. The first polarizing beam splitter film PBS1 (transmits p-polarized light and reflects s-polarized light) reflects the s-polarized light, which remains in the s-polarized state and then passes downward, passes through the second prism PR2 on the lower side, and then passes downward to reach the light splitting optical flat P. The s-polarized light is incident on the second polarizing beam splitter film PBS2 (transmits p-polarized light and reflects s-polarized light) on the light splitting optical flat P, is reflected to the right, and then reaches the second quarter wave plate QWP2. After conversion into circularly polarized light c, the light continues to propagate to the right, is incident on the semi-reflective and semi-transmissive film on the inner side of the semi-transmissive and semi-reflective optical curved sheet C1, and then passes through the semi-transmissive and semi-reflective optical curved sheet C1 to the outside of the module. Another part of the light is reflected to the left and still remains in the circularly polarized state. The circularly polarized light passes through the second quarter wave plate QWP2 again, is converted into p-polarized light, and then passes through the second polarizing beam splitter film PBS2 (transmits s-polarized light and reflects p-polarized light) and the light splitting optical flat P to reach the human eye.

[0162] The embodiment has excellent optical modulation capability, thereby having better optical imaging quality.

[0163] Example 7

[0164] As shown in Fig. 7, the embodiment of the present application provides a prism type multiple-turn near-eye display system, in which a plastic lens is used as the first optical lens L1 in the light-transmitting optical lens group LG1, a plastic lens is used as the second optical lens L2 in the total reflection optical lens group LG2, and the prism group PG is composed of two single plastic prisms, i.e. the first prism PR1 and the second prism PR2, and the splitting plane FS.

[0165] In the embodiment, the splitting plane FS of the prism glue surface is pasted with (or coated with) the first half-reflective half-transmissive splitting film HM1 for splitting, and the upper side of the splitting optical flat P is pasted with (or coated with) the second half-reflective half-transmissive splitting film HM2, whose reflectivity r_C1 = 50%. The lower side of the splitting optical flat P is pasted with the anti-reflection film ARF for reducing the bottom reflection.

[0166] In the display system, the first optical lens L1 is coated with the anti-reflection film on both sides. The first optical lens L1 has a positive refractive power. The optical plastic material K26R with a lower refractive index is used. Both optical surfaces of the first optical lens L1 are optical aspheric surfaces.

[0167] In the display system, the second optical lens L2 is coated with the total reflection film on the left side (the side close to the eye). The optical plastic material OKP1 with a higher refractive index is used for the second optical lens L2. The right side transmissive optical surface of the second optical lens L2 is coated with the anti-reflection film.

[0168] In the display system, the prism group PG is composed of the first prism PR1, the second prism PR2 and the splitting plane FS. The first prism PR1 is a three-prism with two optical surfaces, i.e. the right side surface and the left lower side surface (the remaining surfaces are non-optical surfaces). The right side surface of the first prism PR1 is an aspheric surface coaxial with the optical axis of the first optical lens L1. The left lower side surface is a plane, which is the plane for gluing with the second prism PR2. The prism PR2 is a three-prism with three optical surfaces, i.e. the right upper side plane, the left side surface and the lower side surface. The right upper side plane is glued with the left lower side plane of the first prism PR1 (the splitting plane FS). The left side surface of the second prism PR2 is an aspheric surface coated with the anti-reflection film, which is coaxial with the optical axes of the first optical lens L1 and the second optical lens L2. The lower side surface of the second prism PR2 is an aspheric surface coated with the anti-reflection film, and the optical axis of the lower side surface of the second prism PR2 is at an angle of 85° with the optical axis of the left side surface of the second prism PR2.

[0169] The first half-reflection half-transmission film HM1 is sandwiched between the first prism PR1 and the second prism PR2 in the splitting plane FS. The structure of the bonding surface is in order from top to bottom: the first prism PR1, the first half-reflection half-transmission film HM1, and the second prism PR2. The splitting plane FS can be bonded by optical photosensitive adhesive, or can be bonded by OCA (Optically Clear Adhesive) optical adhesive or other ways.

[0170] In the display system, the inner side (left side, i.e., the side close to the human eye) of the half-transmission half-reflection optical curved sheet C1 is coated with a half-reflection half-transmission film, and the reflectivity r_C1 thereof is 50%. The outer side is coated with an anti-reflection film to reduce reflection, thereby reducing stray light of the virtual image and improving the see-through effect. The material of the half-transmission half-reflection optical curved sheet is K26R. Both the inner side and the outer side are free-form surfaces.

[0171] The splitting optical plane P uses glass BK7 material, and the thickness t_P2 is 0.5 mm.

[0172] The propagation path of the display light of the display system of the embodiment is as follows: the light emitted by the screen SCN passes through the first optical lens L1, the first prism PR1, the first half-reflection half-transmission film HM1 on the splitting plane FS, the second prism PR2, and the second optical lens L2 in sequence, is reflected by the total reflection surface on the left side of the second optical lens L2, and then passes through the second optical lens L2 again, the second prism PR2, and reaches the first half-reflection half-transmission film HM1 on the splitting plane FS. After being reflected by the first half-reflection half-transmission film HM1, the light propagates downward, then passes through the lower side of the second prism PR2 and propagates downward to reach the splitting optical plane P. After being reflected by the second half-reflection half-transmission film HM2 on the splitting optical plane P, the light propagates rightward, and is incident on the half-transmission half-reflection film on the inner side of the half-transmission half-reflection optical curved sheet C1. Part of the light directly passes through the half-transmission half-reflection optical curved sheet to the outside of the module, and the other part is reflected leftward, then passes through the second half-reflection half-transmission film HM2 and the splitting optical plane P, and reaches the human eye.

[0173] The advantages of the embodiment are as follows: the structure and film layers are simple, and the assembly is easy. In addition, since there is no modulation of polarized light, the system is not affected by the material stress of the optical lens, thereby having better imaging quality.

[0174] The above description is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims. The information disclosed in the background section of the present application is only intended to deepen the understanding of the overall background of the present application, and should not be regarded as acknowledging or implying in any form that the information constitutes the prior art known by those skilled in the art.

Claims

1. A prism-type multiple-reflection near-eye display system, characterized in that, include: Micro-display screen, beam-splitting prism assembly, beam-splitting optical plate, and semi-transparent / semi-reflective curved optical plate; among them, The upper horizontal optical path is formed by the beam-splitting prism group spaced apart in front of the display end of the micro display screen. The beam-splitting optical plate is positioned below the beam-splitting prism assembly. A semi-transparent and semi-reflective optical curved plate is positioned in front of the beam-splitting optical plate, and the area behind the beam-splitting optical plate is the position of the human eye. The beam-splitting optical plate and the semi-transparent and semi-reflective optical curved plate form the lower transverse optical path. The light-emitting end of the beam-splitting prism group forms a vertical connecting optical path to the upper surface of the beam-splitting optical plate; The upper horizontal optical path, the vertical connecting optical path, and the lower horizontal optical path constitute the I-shaped display optical path from the display end of the micro-display screen to the human eye position.

2. The prism-type multiple-reflection near-eye display system according to claim 1, characterized in that, The beam-splitting prism assembly is composed of at least two optical prisms and a beam-splitting plane bonded together, with the beam-splitting plane located on the bonded surface of the two optical prisms. The included angle α_PP between the beam-splitting plane and the beam-splitting optical plate satisfies: α_PP < 20°; The included angle α_SP1 between the microdisplay and the beam-splitting plane of the beam-splitting prism group satisfies: 25° < α_SP1 < 65°.

3. The prism-type multiple-reflection near-eye display system according to claim 1 or 2, characterized in that, The included angle α_SP2 between the micro-display and the beam-splitting optical plate satisfies: 25°<α_SP2<65°; The reflectivity r_CP of the semi-transparent and semi-reflective optical plate satisfies: 5% < r_CP < 90%.

4. The prism-type multiple-reflection near-eye display system according to claim 2, characterized in that, In the beam-splitting prism group, the optical prism closest to the display end of the micro-display screen is a light-transmitting optical prism; The outer side of the optical prism at the display end away from the microdisplay is coated with a total reflection film; The surface of the beam-splitting plane is provided with a first polarizing beam-splitting film; or, the surface of the beam-splitting plane is provided with a first polarizing beam-splitting film and a first quarter-wave plate.

5. The prism-type multiple-reflection near-eye display system according to claim 1, characterized in that, The beam-splitting optical plate is an optical plate with a surface coated with a semi-reflective and semi-transparent optical film; or, the beam-splitting optical plate is an optical plate with a surface coated with a polarizing beam-splitting film and interspersed with linear polarizing modes and quarter-wave plates. The semi-transparent and semi-reflective optical curved sheet is an optical plastic curved sheet with a semi-transparent and semi-reflective film coated on one surface and an anti-reflective film coated on the other surface. The Abbe number vd_C1 of the optical plastic curved sheet satisfies: 30 < vd_C1 < 70. The surface of the optical curved sheet can be any one of a spherical surface, an aspherical surface, or a freeform surface. The micro-display screen can be any one of Micro-OLED screen, Micro-LED screen, LCD screen, or equivalent LBS light source.

6. The prism-type multiple-reflection near-eye display system according to claim 1, 2, or 5, characterized in that, Also includes: A group of light-transmitting optical lenses is spaced between the display end of the micro-display screen and the beam-splitting prism group; Alternatively, it may also include: a total internal reflection optical lens group, spaced apart in front of the beam-splitting prism group; both optical prisms of the beam-splitting prism group are light-transmitting optical prisms; Alternatively, it may also include: a light-transmitting optical lens group and a total internal reflection optical lens group, wherein the light-transmitting optical lens group is spaced apart between the display end of the micro-display screen and the beam-splitting prism group, and the total internal reflection optical lens group is spaced apart in front of the beam-splitting prism group, wherein both optical prisms of the beam-splitting prism group are light-transmitting optical prisms.

7. The prism-type multiple-reflection near-eye display system according to claim 6, characterized in that, The display end surface of the micro-display screen is provided with a first linear polarization film; The upper surface of the beam-splitting optical plate is provided with a second quarter-wave plate, a second polarizing beam-splitting film and a second linear polarizing film from top to bottom, and the lower surface of the beam-splitting optical plate is provided with an anti-reflection film. or, The beam-splitting plane of the prism assembly is provided with a first semi-reflective and semi-transparent beam-splitting film. The upper surface of the beam-splitting optical plate is provided with a second semi-reflective and semi-transparent beam-splitting film, and the lower surface of the beam-splitting optical plate is provided with an anti-reflection film.

8. The prism-type multiple-reflection near-eye display system according to claim 6, characterized in that, The display end surface of the micro-display screen is provided with a first linear polarization film; When a total internal reflection optical lens group is set up, a first quarter-wave plate is provided between the beam-splitting prism group and the total internal reflection optical lens group; The upper surface of the beam-splitting optical plate is provided with a second polarizing beam-splitting film and a second linear polarizing film from top to bottom; The lower surface of the beam-splitting optical plate is provided with an anti-reflection film; A second quarter-wave plate is provided between the upper surface of the beam-splitting optical plate and the semi-transparent and semi-reflective optical curved plate; The surface of the beam-splitting plane of the beam-splitting prism group is provided with a first polarizing beam-splitting film; or, the surface of the beam-splitting plane of the beam-splitting prism group is provided with a first semi-reflective and semi-transparent film; or, the surface of the beam-splitting plane of the beam-splitting prism group is provided with a first polarizing beam-splitting film and a first tetramolecular waveplate.

9. The prism-type multiple-reflection near-eye display system according to claim 6, characterized in that, Each optical lens in the light-transmitting optical lens group and the total internal reflection optical lens group has a lens surface shape of any one of spherical, aspherical, or freeform surface; When the surface of an optical lens is aspherical, the aspherical surface has a height H in the direction of the optical axis Z and in the direction perpendicular to the optical axis. The different powers of the height H are H 2 H 4 H 6 H 8 H 10 H 12 H 14 H 16 The aspherical surface has a base radius of R, a taper coefficient of k, and aspherical coefficients of A4, A6, A8, and A. 10 A 12 A 14 and A 16 The aspherical surface profile of an optical lens is represented by the following formula:

10. An AR glasses pair, comprising: The eyeglasses body and the near-eye display system integrated on the eyeglasses body are characterized in that the near-eye display system adopts the prism-type multiple reflection near-eye display system as described in any one of claims 1-9.

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