Optical display devices and AR display devices

Abstract

An optical display device comprising an image source (1), a first prism unit (2), a second prism unit (3), and a first lens unit (4), wherein a first semi-transparent semi-reflective film is provided on the surface (402) of the first lens unit (4) that is away from the first prism unit (2), and the projected light emitted from the image source (1) enters the first prism unit (2) from the first surface (201) of the first prism unit (2), and further enters the second surface (2) of the first prism unit (2) The light passes through total internal reflection by (02), reflection by the third surface (203) of the first prism unit (2), and transmission by the second surface (202) of the first prism unit (2) in sequence before entering the first lens unit (4). After further reflection by the first semi-transparent semi-reflective film, the light passes through the second surface (202) and third surface (203) of the first prism unit (2), and then through the second lens unit (3) in sequence before entering the human eye. This design results in a simple structure, lightweight overall structure, and excellent display effect.

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims the priority of the following Chinese patent applications, the entire contents of which are incorporated herein by reference: Application No. 202310443709.8, titled "Optical Display Device and AR Display Device", filed with the China National Intellectual Property Administration on April 24, 2023; Application No. 2023221818965, titled "Lightweight Near - Eye Display Device", filed with the China National Intellectual Property Administration on August 14, 2023; Application No. 2023218656147, titled "Wide - Viewing - Angle Lightweight Head - Mounted Display Device", filed with the China National Intellectual Property Administration on July 14, 2023; Application No. 2023223562402, titled "Optical Module and Near - Eye Display Device with Glare Elimination", filed with the China National Intellectual Property Administration on August 30, 2023; Application No. 2023228140271, titled "Near - Eye Display Device with Adjustable Refractive Power", filed with the China National Intellectual Property Administration on October 19, 2023; Application No. 2023115297397, titled "Lightweight and Thin - Type Near - Eye Display Device with Glare Elimination", filed with the China National Intellectual Property Administration on November 16, 2023. This application claims the priority of the above - mentioned Chinese patent applications, and the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the field of optical devices, particularly to optical display devices and AR display devices.

Background Art

[0003] Augmented reality (AR) display technology is a technology that uses optical elements to superimpose virtual and real images. Currently, optical devices that realize AR display technology can be broadly classified into two different types. One type projects projection light onto an optical wave guide using a projection optical engine, transmits it through total internal reflection within the wave guide, and then emits it to the human eye. Simultaneously, ambient light also reaches the human eye via the wave guide, allowing for the superimposition of virtual and real images. The other type uses geometric optical elements to guide projection light to the human eye, and similarly, ambient light is also incident on the human eye via geometric optical elements, thereby superimposing virtual and real images.

[0004] In the field of AR display technology, one of the research areas attracting attention in the industry is how to achieve weight reduction in the device structure of display devices that use geometric optical elements. [Overview of the project] [Problems that the invention aims to solve]

[0005] The object of the present invention is to provide an optical display device and an AR display device that have a simple structure, a certain degree of weight reduction in the overall structure, and relatively good display effects. [Means for solving the problem]

[0006] To solve the above technical problems, the present invention provides an optical display device, which includes an image source, a first prism unit, a second prism unit, and a first lens unit.

[0007] Among them, the image source is installed on one side of the first surface of the first prism unit, the first lens unit is installed in contact with the second surface of the first prism unit, the first surface of the second prism unit is installed in contact with the third surface of the first prism unit, and the first surface and the third surface of the first prism unit are closer to the wearer's eyes than the second surface of the first prism unit. The first lens unit is provided with a first semi-transmissive semi-reflective film on the surface on the side away from the first prism unit. The projection light emitted from the image source enters the first prism unit through the first surface of the first prism unit, and then passes through total reflection by the second surface of the first prism unit, reflection by the third surface of the first prism unit, and transmission by the second surface of the first prism unit, and then enters the first lens unit. After being reflected by the first semi-transmissive semi-reflective film, it passes through the second surface and the third surface of the first prism unit and the transmission by the second prism unit, and then enters the human eye.

[0008] Optionally, the included angle α between the second surface and the third surface of the first prism unit satisfies 15° < α < 35°, and the included angle b between the first surface and the second surface of the second prism unit satisfies 15° < b < 25° and a - b ≤ 10°. The second surface of the second prism unit is the surface on the side where the projection light is emitted.

[0009] Optionally, a polarizing film is provided on the third surface of the first prism unit, and a first quarter-wave plate is arranged between the first lens unit and the polarizing film. In addition, a second semi-transmissive semi-reflective film is arranged on the third surface of the first prism unit.

[0010] Optionally, there is a fourth surface of the first prism unit between the first surface and the third surface of the first prism unit, and the fourth surface of the first prism unit is parallel to the second surface of the first prism unit, or the fourth surface of the first prism unit is parallel to the second surface of the second prism unit.

[0011] Optionally, both the first and second prism units are prisms with a refractive index of 1.45 to 1.75 and an Abbe number of 18.0 to 60.0. The first lens unit satisfies the following conditions: focal length f1 is 10mm ≤ f1 ≤ 25mm, refractive index is 1.45 to 1.90, Abbe number is 35.0 to 85.0, radius of curvature R11 of the first surface is R11 ≥ 100mm or R11 ≤ -100mm, and radius of curvature R12 of the second surface is 40mm ≤ R12 ≤ 80mm. Of these, the first surface of the first lens unit is the surface closer to the first prism unit, and the second surface of the first lens unit is the surface further away from the first prism unit. The gap between the first surface of the first lens unit and the second surface of the first prism unit is 0.01 mm to 1.0 mm.

[0012] Optionally, the image source is movable relative to the first prism unit, and the movement distance is less than 2.5 mm.

[0013] Optionally, the angle between the direction in which the image source moves relative to the first prism unit and the optical axis direction of the image source is 0° to 15°.

[0014] Optionally, a second lens unit is further installed between the image source and the first surface of the first prism unit.

[0015] Optionally, the second lens unit and the image source can be synchronized with the first prism unit to adjust the refractive power.

[0016] Optionally, the focal length f2 of the second lens unit satisfies f2 ≥ 50 mm or f2 ≤ -50 mm, the refractive index is 1.45 to 1.90, the Abbe number is 35.0 to 85.0, and the radius of curvature R21 of the first surface and the radius of curvature R22 of the second surface satisfy |R21 - R22| > 50 mm. Of these, the first surface of the second lens unit is the surface on the side away from the first prism unit, and the second surface of the second lens unit is the surface on the side closer to the first prism unit. The gap between the first surface of the second lens unit and the first surface of the first prism unit is 0.05 mm to 3.00 mm.

[0017] Optionally, a third lens unit is further provided on the side of the second surface of the second prism unit, wherein the second surface of the second prism unit is the surface through which the projected light is transmitted through the second prism unit and emitted.

[0018] Optionally, the focal length f3 of the third lens unit satisfies f3 ≥ 50 mm or f3 ≤ -50 mm, the refractive index is 1.45 to 1.90, the Abbe number is 35.0 to 85.0, the radius of curvature R31 of the first surface satisfies R31 ≥ 100 mm or R31 ≤ -100 mm, and the radius of curvature R32 of the second surface satisfies R32 ≥ 100 mm or R32 ≤ -100 mm. Among them, the first surface of the third lens unit is the surface closer to the main body of the second prism unit, and the second surface of the third lens unit is the surface farther from the main body of the second prism unit.

[0019] Optionally, the third lens unit can achieve refractive power adjustment by moving along the optical axis with respect to the second prism unit.

[0020] Optionally, a film system unit is further provided. The film system unit is used to reflect all or part of the light emitted from the image source to the first lens unit and to transmit the light reflected from the first lens unit to the first prism unit. The film system unit is installed between the third surface of the first prism unit and the first surface of the second prism unit.

[0021] Optionally, the first surface of the first prism unit is spherical or aspherical, and the surface of the first lens unit is any combination of spherical, aspherical, freeform, Fresnel, and planar surfaces.

[0022] Optionally, the image source can achieve refractive power adjustment by moving with respect to the first surface of the first prism unit, and the focal length of the first surface of the first prism unit is 25 mm to 200 mm.

[0023] Optionally, it further includes a fourth lens unit. The fourth lens unit is installed close to the first semi-transmissive semi-reflective film, and the focal length of the fourth lens unit is the reciprocal (value with the opposite sign) of the focal length of the first lens unit.

[0024] Optionally, the focal length of the first lens unit is 10 mm to 25 mm.

[0025] Optionally, the film system unit includes at least one of a third semi-transmissive semi-reflective film, a reflective polarizing film, a quarter-wave plate, and an absorptive polarizing film.

[0026] Optionally, the ratio of the transmittance to the reflectance of each semi-transmissive semi-reflective film is 1:9 to 9:1.

[0027] Optionally, the distance between the image source and the first surface of the first prism unit is 0.25 mm to 3.0 mm.

[0028] Optionally, the optical display device further satisfies the following conditions: R1 ≤ -100 mm or R1 ≥ 100 mm, -40 mm ≤ R2 ≤ -100 mm, R3 ≤ -200 mm or R3 ≥ 18 mm, Among them, R1 represents the radius of curvature of the surface of the first lens unit close to the fourth lens unit, R2 represents the radius of curvature of the side of the first lens unit away from the fourth lens unit, and R3 represents the radius of curvature of the first surface of the first prism unit.

[0029] Optionally, the aspherical surface satisfies the following formula:

Equation

[0030] Optionally, the optical display device also meets the following conditions: In JPEG2026529165000003.jpg52150, R represents the radius of curvature in mm, Len1_S1 indicates the lens surface on the first lens unit close to the fourth lens unit, Len1_S2 indicates the lens surface on the first lens unit away from the fourth lens unit, and P2_S3 indicates the first surface of the first prism unit.

[0031] Optionally, a first polarization unit is further provided, the first polarization unit being located between the first prism unit and the second prism unit, and used to reflect imaging light in the first polarization transmission direction to the first lens unit and to transmit imaging light in the second polarization transmission direction, the first polarization transmission direction exhibiting a 90° angle with respect to the second polarization transmission direction, and the first polarization transmission direction being the same as the polarization transmission direction of the image source, the first semi-transmitting semi-reflective film reflecting imaging light in the first polarization transmission direction, passing it sequentially through the first prism unit and the second prism unit before entering the human eye, and transmitting real-world light, passing it sequentially through the first prism unit and the second prism unit before entering the human eye. A second polarizing unit is further attached to the second surface of the second prism unit, and the second polarizing unit is expected to transmit light parallel to the third polarizing transmission direction and reflect light perpendicular to the third polarizing transmission direction, with the third polarizing transmission direction being the same as the second polarizing transmission direction.

[0032] Optionally, the first polarization unit includes a first linear polarizer, a polarizing reflector, and a second quarter-wave plate, which are sequentially arranged along the direction from the second prism unit toward the first prism unit.

[0033] Optionally, the image source may be further provided with a third polarization unit, which is used to convert the image light into 45° linearly polarized light.

[0034] Optionally, the second polarizing unit includes a second linear polarizer, and the third polarizing unit includes a third linear polarizer.

[0035] Optionally, 45° linearly polarized light is reflected once by the second surface of the first prism unit to form the first ray, the first ray is reflected a second time by the first polarization unit to form the second ray, the second ray is reflected a third time by the first semi-transparent semi-reflective film to form the third ray, the third ray is converted into a fourth ray by the first polarization unit, then passes through the second polarization unit before entering the human eye. The first ray is 45° linearly polarized, the second ray is left-handed circularly polarized, the third ray is right-handed circularly polarized, and the fourth ray is -45° linearly polarized. The second polarization unit transmits -45° linearly polarized light and reflects 45° linearly polarized light.

[0036] Optionally, a fifth lens unit may be included, which is positioned between the image source and the first prism unit, and which includes at least one lens.

[0037] The refractive power can be adjusted by optionally synchronizing the movement of the fifth lens unit and the image source relative to the first prism unit.

[0038] Optionally, further equipped with a polarization conversion unit, The image source has a linear polarizing film on its light-emitting side, and further It includes a film system unit, the film system unit includes a polarizing reflective unit, and is attached to the third surface of the first prism. The polarization conversion unit is located between the first prism unit and the first lens unit, or installed between the polarization reflection unit and the first prism unit. The thickness of the linear polarizing film is 60nm to 250nm, the thickness of the film system unit is 90nm to 280nm, the thickness of the polarization conversion unit is 30nm to 100nm, and the thickness of the semi-transparent, semi-reflective film is 50nm to 300nm. The imaging light emitted from the image source is converted into linearly polarized light by a linearly polarizing film. This linearly polarized light enters the first prism unit, undergoes total internal reflection, and then reaches the film system unit. It is then reflected by the film system unit to the first lens unit, and then reflected again by the first lens unit to reach the first prism unit. Finally, it passes through the film system unit and the second prism unit in that order before reaching the human eye and forming an image.

[0039] Optionally, the polarization conversion unit is a quarter-wave plate, and the angle between the reflection axis of the film system unit and the slow axis of the polarization conversion unit is 45°±1°.

[0040] Optionally, the polarizing reflective unit is a polarizing reflective film.

[0041] Optionally, the film system unit further comprises a polarization absorption unit, the polarization absorption unit being a polarization absorption film, further located between the polarization reflection unit and the second prism unit, and the absorption axis of the polarization absorption unit being parallel to the reflection axis of the polarization reflection unit.

[0042] Optionally, the image source can be further moved relative to the first prism unit, with a movement distance of less than 5 mm.

[0043] Optionally, the angle between the direction in which the image source moves relative to the first prism unit and the optical axis direction of the image source is between 0° and 15°.

[0044] Optionally, a sixth lens unit may be provided, which is located on the light emission side of the image source, and linearly polarized light enters the first prism unit via the sixth lens unit.

[0045] Optionally, the focal length of the sixth lens unit is between 5mm and 50mm.

[0046] Optionally, the image source and the sixth lens unit can be moved synchronously with respect to the first prism unit, with a movement distance of less than 4 mm.

[0047] Optionally, the angle between the direction in which the image source and the sixth lens unit move synchronously with respect to the first prism unit and the optical axis direction of the image source is 0° to 10°.

[0048] Optionally, an additional polarizing plate is provided on the side of the second prism unit closest to the human eye, with a thickness of 60 nm to 250 nm.

[0049] Optionally, each lens unit includes at least one lens.

[0050] The surface shape of each lens can be any combination of spherical, aspherical, freeform, Fresnel, and planar.

[0051] Optionally, the first lens unit is a curved lens.

[0052] Arbitrarily, an aspherical surface satisfies the following equation.

number

[0053] Optionally, a seventh lens unit may be included, the seventh lens unit being positioned on the side of the first lens unit away from the wearer's eye, and the focal length of the seventh lens unit being inversely proportional to (with opposite signs) the focal length of the first lens unit. The second prism unit includes at least one Fresnel lens. The membrane unit is installed between the first prism unit and the second prism unit.

[0054] Optionally, the film system unit includes at least one of a fourth semitransmitting semi-reflective film, a reflective polarizing film, a quarter-wave plate, and an absorbing polarizing film.

[0055] The ratio of transmittance to reflectance of each semi-transparent, semi-reflective film is arbitrarily between 1:9 and 9:1.

[0056] Optionally, the air gap between the first prism unit and the first lens unit is 0.01 mm to 1 mm.

[0057] Optionally, the second prism unit includes one Fresnel lens, the angle between the line connecting the roots of two adjacent teeth of the Fresnel lens and the corresponding tooth width direction is 15° to 35°, the tooth width of the Fresnel lens is 0.1 mm or more, the draft angle of the Fresnel lens teeth is 60° to 120°, and the refractive indices of both the Fresnel lens and the first prism unit are 1.45 to 1.75, and the Abbe numbers are both 18.0 to 60.0.

[0058] Optionally, a membrane system unit may be included, which is installed between the first prism unit and the second prism unit. The second prism unit is a Fresnel lens and is positioned close to the third surface of the first prism unit, with the Fresnel surface of the Fresnel prism positioned on the side closest to the wearer's eye, and satisfying the following conditions: sin(β)*n>sin(max(aor)) or sin(β)*n <sin(min(aor)) ))、 r / pitch<0.05, R / pitch < 0.05, In the formula, β is the draft angle of each tooth, αor is the range of the angle between the line connecting the tip and root of each tooth to any point on the aperture and the normal to the aperture, max is the maximum value of αor, min is the minimum value of αor, n is the refractive index of the Fresnel lens material, pitch is the tooth width of each tooth, r is the chamfer radius of the root of each tooth, and R is the chamfer radius of the tip of each tooth.

[0059] Optionally, the pitch value range of the Fresnel surface of the second prism unit is 0.15 mm to 0.6 mm, and the range of values ​​for both r and R is 0.05 mm to 0.02 mm.

[0060] Optionally, the film system unit includes at least one of a fifth semi-transmissive semi-reflective film, a reflective polarizing film, a quarter-wave plate, and an absorbing polarizing film.

[0061] Optionally, the air gap between the first prism unit and the first lens unit is 0.01 mm to 1.0 mm.

[0062] Optionally, the first lens unit is a curved lens, and the radius of curvature R11 of the first surface of the first lens unit satisfies R11 ≥ 150 mm or R11 ≤ -150 mm, the radius of curvature R12 of the second surface of the first lens unit satisfies 40 mm ≤ R12 ≤ 75 mm, the first surface of the first prism unit is curved, and the radius of curvature R13 satisfies R13 ≥ 22 mm or R13 ≤ -100 mm, the first surface of the first lens unit is the surface closer to the first prism unit, and the second surface of the first lens unit is the surface further away from the first prism unit.

[0063] Optionally, an eighth lens unit may be included, the eighth lens unit being positioned in close proximity to the first semi-transparent semi-reflective film, and the focal length of the eighth lens unit being the inverse of (opposite sign) the focal length of the lens unit.

[0064] Optionally, the focal length of the first lens unit is between 10mm and 25mm.

[0065] The refractive power is adjusted by optionally moving the image source relative to the first prism unit. [Effects of the Invention]

[0066] In the optical display device provided in this application, the projection light emitted from the image source is repeatedly reflected within the first prism unit through the cooperation between the first prism unit and the first lens unit. As a result, the transmission path of the projection light is repeatedly folded back within the first prism unit, providing the projection light with a sufficiently large transmission path length. Furthermore, the projection light only needs to be reflected twice within the first prism unit, thereby ensuring a sufficient optical path length for the projection light while avoiding the problem of the first prism unit becoming excessively large due to too many reflections, which is advantageous for reducing the overall weight of the display device. In addition, since the first surface of the first prism unit is the side closer to the wearer's eyes, and the image source emits projection light to the first surface of the first prism unit, the image source is installed on the side of the first prism unit closer to the wearer's head, making it easier to install the image source and simplifying the installation structure of the image source. The optical display device provided in this application has a simple structure and a relatively small overall size, achieving a degree of weight reduction and good display effect, which is advantageous for the device's wide application. [Brief explanation of the drawing]

[0067] To more clearly illustrate one embodiment of this application or the technical configuration of the prior art, the drawings used in describing the embodiment or the prior art are briefly introduced below. Clearly, the drawings described below represent only a few embodiments of the present invention. Those skilled in the art can obtain other drawings based on these without requiring any creative work.

[0068] [Figure 1] This is a schematic diagram of the structure of an optical display device provided by an embodiment of this application. [Figure 2] This is a spot diagram of the structure of the optical display device provided in the embodiment of this application when ab = 6. [Figure 3] This is a spot diagram of the structure of the optical display device provided in the embodiment of this application when ab = 0. [Figure 4] This is a spot diagram of the structure of the optical display device provided in the embodiment of this application when ab = 10. [Figure 5] This is a schematic diagram of the structure of another optical display device provided by the embodiments of this application. [Figure 6] This is a schematic diagram of the structure of another optical display device provided by the embodiments of this application. [Figure 7] This is a schematic diagram of the structure of another optical display device provided by the embodiments of this application. [Figure 8] This is a schematic diagram of the structure of another optical display device provided by the embodiments of this application. [Figure 9] This is an MTF diagram at 0D refractive index for one embodiment of this application. [Figure 10] This is a spot diagram at 0D refractive index for one embodiment of this application. [Figure 11] This is an MTF diagram at -3D refractive index for one embodiment of the present application. [Figure 12] This is a spot diagram at -3D refractive index for one embodiment of the present application. [Figure 13] This is an MTF diagram at a refractive index of -7D for one embodiment of this application. [Figure 14] This is a spot diagram at a refractive index of -7D according to one embodiment of this application. [Figure 15] This is a schematic diagram of the structure of another optical display device provided by one embodiment of this application. [Figure 16] This figure shows the cheek reflex principle according to one embodiment of this application. [Figure 17] This is a schematic diagram showing the configuration of each polarizing unit in one embodiment of the present application. [Figure 18] This is a schematic diagram of the structure of another optical display device provided by one embodiment of this application. [Figure 19] This is a schematic diagram of refractive power adjustment in one embodiment of the present application. [Figure 20]This is an MTF curve diagram at 0D refractive index for one embodiment of the present application. [Figure 21] This is an MTF curve diagram for a 6D refractive index according to one embodiment of this application. [Figure 22] This is an MTF curve diagram at 0D refractive index for one embodiment of the present application. [Figure 23] This is an MTF curve diagram for a 6D refractive index according to one embodiment of this application. [Figure 24] This is an MTF curve diagram at 0D refractive index for one embodiment of the present application. [Figure 25] This is an MTF curve diagram for a 6D refractive index according to one embodiment of this application. [Figure 26] This is an MTF curve diagram at 0D refractive index for one embodiment of the present application. [Figure 27] This is an MTF curve diagram for a 6D refractive index according to one embodiment of this application. [Figure 28] This is an MTF curve diagram at 0D refractive index for one embodiment of the present application. [Figure 29] This is an MTF curve diagram for a 6D refractive index according to one embodiment of this application. [Figure 30] This is a schematic diagram of the structure of another optical display device provided by one embodiment of this application. [Figure 31] This is a schematic diagram of the structure of the second prism unit in one embodiment of the present application. [Figure 32] This is a magnified view I of the second prism unit in Figure 21. [Figure 33] This is an optical path diagram of another optical display device provided in one embodiment of this application. [Figure 34] This is a principal ray path diagram of one embodiment of the present application. [Figure 35] This is a magnified view of part A in Figure 31. [Figure 36] This is a simulated optical path diagram for the second prism unit in one embodiment of this application, where β=0°, R=0μm, and r=0μm. [Figure 37]This is a simulation diagram of the overall positive illuminance distribution in one embodiment of this application, where β=0°, R=0μm, and r=0μm for the second prism unit (without reducing the threshold energy). [Figure 38] This is a simulation diagram of the overall positive illuminance distribution in one embodiment of this application, where β=0°, R=0μm, and r=0μm for the second prism unit (after reducing the threshold energy). [Figure 39] These are (a) a simulated stray light path diagram and (b) a partially enlarged view of portion B in the case of β=0°, R=0μm, and r=0μm for the second prism unit in one embodiment of this application. [Figure 40] This is a simulation diagram of the overall positive illuminance distribution of stray light in one embodiment of the present application, where β=0°, R=0μm, and r=0μm for the second prism unit. [Figure 41] This is a simulated optical path diagram for the second prism unit in one embodiment of this application, where β=0°, R=25μm, and r=25μm. [Figure 42] This is a simulation diagram of the overall positive illuminance distribution for the second prism unit in one embodiment of this application, where β=0°, R=25um, and r=25um (threshold energy has not been reduced). [Figure 43] This is a simulation diagram of the overall positive illuminance distribution in one embodiment of the present application for the second prism unit with β=0°, R=25um, and r=25um (after reducing the threshold energy). [Figure 44] This is a simulation illuminance distribution diagram (a) and a partial enlarged view (b) of portion C of stray light in the positive direction for the second prism unit in one embodiment of this application, where β=0°, R=25um, and r=25um. [Figure 45] This is a forward-direction simulated illuminance distribution diagram relating to stray light ghosting (dragging image) in the case of β=0°, R=25um, and r=25um for the second prism unit in one embodiment of this application. [Figure 46]This is a simulated optical path diagram for the second prism unit in one embodiment of this application, where β=12°, R=5μm, and r=5μm. [Figure 47] This is a simulation diagram of the overall positive illuminance distribution in one embodiment of this application, where the second prism unit has β=12°, R=5μm, and r=5μm (threshold energy has not been reduced). [Figure 48] This is a simulation diagram of the overall positive illuminance distribution in one embodiment of this application, where the second prism unit has β=12°, R=5μm, and r=5μm (after reducing the threshold energy). [Figure 49] These are (a) a simulated stray light path diagram and (b) a partially enlarged view of portion D in the case of β=12°, R=5μm, and r=5μm for the second prism unit in one embodiment of this application. [Figure 50] This is a forward-direction simulated illuminance distribution diagram relating to stray light ghosting (dragging image) in one embodiment of the present application, where the second prism unit has β=12°, R=5μm, and r=5μm.

[0069] (Explanation of symbols) Image source, 2. First prism unit, 201. First surface of the first prism unit, 202. Second surface of the first prism unit, 203. Third surface of the first prism unit, 204. Fourth surface of the first prism unit, 3. Second prism unit, 301. First surface of the second prism unit, 302. Second surface of the second prism unit, 4. First lens unit, 5. First quarter-wave plate, 6. Second lens unit, 601. First surface of the second lens unit, 602. Second surface of the second lens unit, 7. Third lens unit, 701. First surface of the third lens unit, 702. Second surface of the third lens unit, 8. Fourth lens unit, 9. First polarizing unit, 91. First linear polarizer, 92. Polarizing reflector, 93. Second quarter-wave plate, 10. Second polarizing unit, 11. Human eye, 12. Third polarizing unit, 13. Fifth lens unit, 14. Sixth lens unit, 15. Seventh lens unit. [Modes for carrying out the invention]

[0070] To enable those skilled in the art to better understand the structure of the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments. Clearly, the embodiments described are only some, and not all, embodiments of the present invention. All other embodiments that can be obtained by those skilled in the art without requiring any creative work based on the embodiments of the present invention are within the scope of the protection of the present invention.

[0071] As shown in Figures 1 to 7, in one specific embodiment of this application, the optical display device may include the following:

[0072] Image source 1, first prism unit 2, second prism unit 3, first lens unit 4.

[0073] Of these, image source 1 is installed on the first surface 201 side of the first prism unit, and the first lens unit 4 is installed in contact with the second surface 202 of the first prism unit. The first surface of the second prism unit 3 is installed in contact with the third surface 203 of the first prism unit, and the first surface 201 and the third surface 203 of the first prism unit are closer to the wearer's eye than the second surface 202 of the first prism unit. A first semi-transparent semi-reflective film is installed on the surface of the first lens unit 4 that is away from the first prism unit 2.

[0074] The projected light emitted from image source 1 enters the first prism unit 2 from the first surface 201 of the first prism unit, undergoes total internal reflection by the second surface 202 of the first prism unit, reflection by the third surface 203 of the first prism unit, and transmission by the second surface 202 of the first prism unit before entering the first lens unit 4. After being reflected by the first semi-transparent semi-reflective film, it is sequentially transmitted through the second surface 202 and third surface 203 of the first prism unit and the second prism unit 3 before being emitted and entering the human eye 11.

[0075] Referring to Figure 1, in the embodiment shown in Figure 1, the projected light emitted from the image source 1 first passes through the first surface 201 of the first prism unit and enters the first prism unit 2, where it undergoes total internal reflection at the second surface 202 of the first prism unit, and then enters the third surface 203 of the first prism unit. Since a polarizing film is provided on the third surface 203 of the first prism unit, the polarizing film partially reflects the projected light, and the reflected projected light is polarized. This polarized light is transmitted again to the second surface 202 of the first prism unit, transmitted through the second surface 202 of the first prism unit, passes through the first quarter-wave plate 5 for the first time, and enters the first lens unit 4 via the first surface 401 of the first lens unit. Furthermore, it is reflected by the semi-transparent semi-reflective film on the second surface 402 of the first lens unit, and the polarized light passes through the first surface 401 of the first lens unit a second time, and the first quarter-wave plate 5 a second time, before entering the first prism unit 2. Because the polarized light passes through the first quarter-wave plate 5 twice, its polarization direction changes. When the polarized light is incident on the third surface 203 of the first prism unit 2, where the polarizing film is installed, it is directly transmitted. Therefore, the polarized light passes sequentially through the second surface 202 and the third surface 203 of the first prism unit before being incident on the second prism unit 3. After passing through the second prism unit 3, it is emitted to the aperture, which is located at the position of the human eye 11. In other words, the light that has passed through the second prism unit 3 can be incident on the human eye 11.

[0076] Light reflected by the polarizing film and then reflected again by the first semi-transparent semi-reflective film must be able to pass through the polarizing film. Therefore, an element that changes the polarization state of light must be placed between the polarizing film and the first semi-transparent semi-reflective film. By passing the light through this element twice, the polarization state changes, changing from a state in which it can be reflected by the polarizing film to a state in which it can pass through the polarizing film. In this embodiment, a first quarter-wave plate 5 is used to realize this function. According to the above principle, the first quarter-wave plate 5 needs to be placed between the polarizing film and the first semi-transparent semi-reflective film. In actual use, the first quarter-wave plate 5 can be attached to the polarizing film or the first semi-transparent semi-reflective film, or it can be placed between the first lens unit 4 and the first prism unit 2, or on any surface adjacent to both.

[0077] In the embodiment shown in Figure 1, a polarizing film is provided on the third surface 203 of the first prism unit to allow partial transmission and partial reflection of the projected light when it is first incident on the third surface 203 of the first prism unit, and a first quarter-wave plate 5 is provided between the polarizing film and the first semi-transparent semi-reflective film. However, in actual applications, it is not always necessary to provide a polarizing film on the third surface 203 of the first prism unit, nor is it always necessary to provide the first quarter-wave plate 5 between the polarizing film and the first semi-transparent semi-reflective film. In another arbitrary embodiment of this application, a second semi-transparent semi-reflective film can also be provided on the third surface 203 of the first prism unit. In this case, it is not necessary to provide the first quarter-wave plate 5, and the projected light can still be partially reflected and partially transmitted as it passes through the third surface 203 of the first prism unit.

[0078] Furthermore, the third surface 203 of the first prism unit itself has the function of partially reflecting and partially transmitting incident light. The ratio of reflection to transmission depends on the angle of the incident light. Therefore, in actual applications, it is conceivable to omit the polarizing film and the second semi-transparent semi-reflective film from the third surface 203 of the first prism unit.

[0079] Referring to the embodiment shown in FIG. 1, as can be seen, both the first surface 201 and the third surface 203 of the first prism unit in the present application are installed on the side of the second prism unit 3 closer to the human eye 11 of the wearer, and the second surface 202 of the first prism unit is installed on the side of the second prism unit 3 away from the human eye 11 of the wearer. The image source 1 emits projection light onto the first surface 201 of the first prism unit. Therefore, the image source 1 is installed on the side of the first prism unit 2 closer to the human eye 11 of the wearer. Compared with the case where the image source 1 is installed on the side of the first prism unit 2 away from the human eye 11 of the wearer, the image source 1 in this embodiment is easy to install and helps to reduce the complexity of the installation structure of the image source 1.

[0080] Furthermore, in this embodiment, after the projection light is incident on the first prism unit 2, it is only reflected twice. Thereby, while sufficiently ensuring the optical path length of the projection light, it is possible to avoid the volume of the first prism unit 2 being overly increased due to multiple reflections. Also, since the projection light in the present application is only reflected twice within the first prism unit 2, the degree of divergence of the projection light when passing through the first prism unit 2 does not become overly large. Therefore, in this embodiment, an image source 1 capable of outputting a wider projection light area can be selected, that is, projection light for an image with a wider area can be output. As a result, the imaging screen formed by the projection light emitted after passing through the first prism unit 2, the second prism unit 3, and the first lens unit 4 in sequence is sufficiently large, and the distortion of the image due to divergence is relatively small, thereby ensuring the display effect. Therefore, in actual applications, the light-emitting area of the image source 1 that outputs the projection light can be set to be not less than a predetermined area.

[0081] In one embodiment, the included angle α between the second surface 202 and the third surface 203 of the first prism unit satisfies 15° < α < 35°, the included angle b between the first surface 301 and the second surface 302 of the second prism unit satisfies 15° < b < 25°, and a - b ≤ 10°. The second surface 302 of the second prism unit is the surface on the side that emits the projection light.

[0082] The structural shapes of the first prism unit 2 and the second prism unit 3 directly affect the occupied space volume of the entire optical display device, the imaging effect, and the like.

[0083] In the first prism unit 2, if the included angle α between the second surface 202 and the third surface 203 of the first prism unit is too large or too small, the requirement that the projection light is reflected twice in the first prism unit 2 and then emitted cannot be satisfied. If the included angle α is too small, the projection light emitted from the image source 1 will be reflected multiple times in the first prism unit 2, or the requirement that the projection light emitted from the image source 1 is totally reflected at the second surface 202 of the first prism unit cannot be satisfied. If the included angle α is too large, the projection light emitted from the image source 1 will be emitted from the first prism unit 2 after being reflected only once in the first prism unit 2, and the requirement of two - time reflection cannot be satisfied. Therefore, in this embodiment, by making the included angle α of the first prism unit 2 fall within this angular range, it is ensured that the requirement that the projection light emitted from the image source 1 is reflected twice in the first prism unit 2 is realized.

[0084] Regarding the second prism unit 3, its main function is to compensate for the optical path difference generated by the repeated reflection of the projection light emitted from different light - emitting positions on the image source 1 in the first prism unit 21. If the included angle b between the first surface 301 and the second surface 302 of the second prism unit is too small, the purpose of compensating the optical path difference cannot be achieved. If the included angle b is too large, the optical path difference is over - compensated, an inverse optical path difference is added, and as a result, a relatively large image distortion occurs, affecting the actual imaging quality. Therefore, in this embodiment, in order to ensure the correction effect on the projection light and guarantee the imaging quality of the projection light, the included angle b is set to satisfy 15° < b < 25° and a - b ≤ 10°.

[0085] When a - b corresponds to different values, specific test data can be referred to in FIGS. 2 to 4.

[0086] Figure 2 is a spot diagram of image quality when ab = 6°. In Figure 2, the field of view -13.58° corresponds to a width of 7.155 mm, the central field of view 0° corresponds to a width of 7.35 mm, and the field of view 13.58° corresponds to a width of 7.221 mm, resulting in a distortion of (7.221 - 7.155) / 7.35, which is approximately 1%.

[0087] Figure 3 is a spot diagram of the image quality when ab = 0°. In Figure 3, the field of view -13.58° corresponds to a width of 7.245 mm, the central field of view 0° corresponds to a width of 7.342 mm, and the field of view 13.58° corresponds to a width of 7.237 mm. The distortion is (7.245 - 7.237) / 7.342, which is approximately 0.1%.

[0088] Figure 4 is a spot diagram of image quality when ab = 10°. In Figure 4, the field of view -13.58° corresponds to a width of 7.204 mm, the central field of view 0° corresponds to a width of 7.416 mm, and the field of view 13.58° corresponds to a width of 7.375 mm. The distortion is (7.375 - 7.204) / 7.416, which is approximately 2.2%.

[0089] In summary, the statistical results of the distortion values ​​when ab and ab have different values ​​are shown in Table 1 below.

[0090] [Table 1]

[0091] As can be seen from Examples 1-3, as ab gradually increases from 0°, the impact of module thickness on image quality is relatively small, but distortion is relatively large. While it becomes easier to make the module thinner, the asymmetry of the image (e.g., becoming trapezoidal) increases. Beyond a certain level, the asymmetry of the image begins to limit image quality. Beyond 10°, the image quality (distortion) is basically unacceptable. Therefore, by limiting ab ≤ 10°, it is possible to ensure that the projection screen has a better display effect.

[0092] In this embodiment, the first lens unit 4 plays a role in reflecting the projected light, while at the same time playing a role in correcting aberrations with respect to the projected light.

[0093] Furthermore, as shown in the embodiments in Figures 1 to 7, the projected light emitted from different positions on the image source 1 is reflected by the two surfaces of the first prism unit 2, resulting in a difference in their optical path lengths. Therefore, in this embodiment, the second prism unit 3 is further positioned adjacent to the third surface 203 side of the first prism unit, and by adjusting the optical path lengths of the projected light emitted from different positions, the optical path lengths of the projected light in each part are made almost identical, thereby reducing image distortion and ensuring the display effect of the projected screen.

[0094] In the embodiments shown in Figures 1 to 4, the first surface 201, second surface 202, and third surface 203 of the first prism unit are all planar, and the first surface 301 and second surface 302 of the second prism unit are also planar. However, in actual applications, the first surface 201, second surface 202, and third surface 203 of the first prism unit do not necessarily have to be planar, and may be curved surfaces having an aberration correction function. Similarly, the first surface 301 and second surface 302 of the second prism unit may also be curved, and this application will not provide further details to avoid duplication.

[0095] Furthermore, in order to reduce the overall volume and weight of the optical system and improve safety of use without affecting the imaging effect, a fourth surface 204 of the first prism unit is provided between the first surface 201 and the third surface 203 of the first prism unit. The fourth surface 204 of the first prism unit is parallel to the second surface 202 of the first prism unit, or the fourth surface 204 of the first prism unit is parallel to the second surface 302 of the second prism unit.

[0096] The presence of the fourth surface 204 of the first prism unit reduces the thickness, volume, and weight of the first prism unit 2 and the entire optical system without affecting the final optical display effect.

[0097] Next, the presence of the fourth surface 204 of the first prism unit prevents the formation of a sharp edge between the first surface 201 and the third surface 203 of the first prism unit. As can be seen from the figure, the fourth surface 204 of the first prism unit is located on the side closer to the wearer's eye. If the fourth surface 204 of the first prism unit were absent, the sharp edge formed between the first surface 201 and the third surface 203 of the first prism unit could significantly endanger the wearer's safety.

[0098] Therefore, the presence of the fourth surface 204 of the first prism unit reduces the overall volume and thickness of the optical system, achieving a lighter and thinner overall design, as well as significantly improving safety and comfort during wear.

[0099] Furthermore, in order to further improve the display effect of the projected image of the entire optical display device, in another optional embodiment of this application, a second lens unit 6 may be provided between the image source 1 and the first surface 201 of the first prism unit, as shown in Figure 5. The second lens unit 6 can play a role in further removing aberrations from the projected light.

[0100] Of course, the method for eliminating aberrations in the projected light is not limited to the above-described embodiment. As shown in Figure 3, in another arbitrary embodiment of this application, a third lens unit 7 can be further provided on the side of the second prism unit 3 that emits the projected light, that is, the side closer to the human eye 11.

[0101] Furthermore, as shown in Figure 6, in actual applications, a second lens unit 6 may be provided between the image source 1 and the first prism unit 2, and a third lens unit 7 may be further provided on the side of the second prism unit 3 closer to the human eye 11. This also allows the same technical configuration of this application to be realized.

[0102] Based on the above discussion, and considering that in the process of actually wearing and using the optical display device, the wearer may be nearsighted, and the degree of nearsightedness may differ from wearer to wearer, another optional embodiment of this application may further include the following configuration.

[0103] The relative distance between image source 1 and the first surface 201 of the first prism unit is adjustable, and the change in relative distance is less than 2.5 mm.

[0104] By changing the different positions between the image source 1 and the first surface 201 of the first prism unit, the different imaging positions of the projected light can be changed, thereby allowing the device to be adapted and used by wearers with different degrees of myopia. In other words, in this embodiment, the refractive power of the entire optical display device can be changed by changing the relative distance between the image source 1 and the first surface 201 of the first prism unit.

[0105] In actual applications, if the displacement distance of the first prism unit of image source 1 relative to the first surface 201 is too large, the boundary of image source 1 on the side closer to the human eye 11 will be closer to the human eye 11 than the second surface 302 of the second prism unit. When image source 1 is operating, a relatively large amount of heat is generated, and if it is close to the human eye 11, discomfort will occur when worn. Furthermore, if the displacement distance of image source 1 is too large, a relatively large movable space must be secured for the movement of image source 1, which increases the overall volume of the optical display device, making discomfort during wear more likely. In addition, the following occurs: image distortion, a significant reduction in the field of view (FOV), and if it moves to the boundary of the range, the edges of the displayed image may not be displayed completely and clearly, making it difficult to guarantee the imaging effect. The maximum displacement of the first prism unit of image source 1 relative to the first surface 201 can be set to 2.5 mm. In other words, by changing the displacement amount within the range of 0 to 2.5 mm, the refractive power of the entire optical display device can be adjusted within the range of 0D to 6D, while also reducing image distortion and field of view reduction to some extent, and further improving the image display effect.

[0106] In actual use, in order to ensure the overall lightness and thinness of the optical system and to ensure the integrity and display effect of the display screen, the angle between the direction of movement of the image source 1 relative to the first prism unit 2 and the optical axis direction of the image source 1 is 0° to 15°.

[0107] In actual use, if the image source 1 is too large, moving the image source 1 to the edge of the range will prevent the display content located at the edge of the image source 1's emission surface from being properly incident on and guided to the first prism unit 2 due to constraints such as the optical lens, resulting in a missing portion of the image ultimately seen by the eye. Therefore, by ensuring that the direction of movement of the image source 1 exhibits a constant angle with respect to the optical axis, that is, by forming a movement component parallel to the light-emitting surface of the image source 1 during movement, the image light emitted from the image source 1 can be properly incident on and guided to the first prism unit 2 throughout the entire movement range. Within the adjustment range of the refractive power, the completeness of the final image is maintained, and the entire emission surface of the image source 1 can be fully utilized.

[0108] However, this angle must not become too large. When the image source 1 moves, the movement component parallel to the emission surface of the image source 1 should be relatively small, and the main movement component of the image source 1 should be along the optical axis. If this angle is too large, that is, when the image source 1 moves, the movement component parallel to the emission surface of the image source 1 will be too large, and in order for all the imaging light emitted from the image source 1 to enter the incident surface of the first prism unit 2 over the entire refractive power adjustment range, the incident surface of the first prism unit 2 would have to be very large, the overall volume of the device would also become very large, and the volume of the augmented reality device would also become relatively large, making it difficult to meet the requirements for lightweight and thin design.

[0109] In this embodiment, the angle is preferably 7°, which ensures a lightweight and thin design while simultaneously ensuring the integrity of the display screen and guaranteeing the display effect.

[0110] Even in an embodiment where the second lens unit 6 is provided between the image source 1 and the first surface 201 of the first prism unit, by moving the image source 1 to change the distance from the first prism unit 2, a change in refractive power can be achieved. Similarly, by moving the second lens unit 6 relative to the first prism unit 2, or by synchronously moving the image source 1 and the second lens unit 6, a change in refractive power can also be achieved. This is not limited in this embodiment.

[0111] In an optical display device including the third lens unit 7, by moving the third lens unit 7 relative to the second surface 302 of the second prism unit and changing the distance therebetween, the refractive power of the entire optical display device can also be changed. This will not be described in detail in this embodiment.

[0112] To further introduce the optical display device of this application, the specific structural parameters of each optical element will be described below.

[0113] In one specific embodiment of this application, further, the included angle α between the second surface 202 and the third surface 203 of the first prism unit satisfies 15° < α < 35°, and the included angle b between the first surface 301 and the second surface 302 of the second prism unit satisfies 15° < b < 25° and α - b ≤ 10°. The second surface 302 of the second prism unit is the surface on the side that emits the projected light.

[0114] Furthermore, both the first prism unit 2 and the second prism unit 3 can be prisms with a refractive index of 1.45 to 1.75 and an Abbe number of 18.0 to 60.0.

[0115] The first lens unit 4 can be a lens that satisfies the following conditions: focal length f1 of 10mm ≤ f1 ≤ 25mm, refractive index of 1.45 to 1.90, Abbe number of 35.0 to 85.0, radius of curvature R11 of the first surface 401 of R11 ≥ 100mm or R11 ≤ -100mm, and radius of curvature R12 of the second surface 402 of 40mm ≤ R12 ≤ 80mm. Of these, the first surface 401 of the first lens unit is the surface closer to the first prism unit 2, and the second surface 402 of the first lens unit is the surface further away from the first prism unit 2.

[0116] Furthermore, the gap between the first surface 401 of the first lens unit and the second surface 202 of the first prism unit is 0.01 mm to 1.0 mm.

[0117] As described above, a second lens unit 6 can be installed between the image source 1 and the first surface 201 of the first prism unit in this application. Specifically, the second lens unit 6 can satisfy a focal length f2 of f2 ≥ 50 mm or f2 ≤ -50 mm, a refractive index of 1.45 to 1.90, an Abbe number of 35.0 to 85.0, and the radius of curvature R21 of the first surface 601 and the radius of curvature R22 of the second surface 602 satisfy |R21-R22| > 50 mm. Of these, the first surface 601 of the second lens unit is the surface on the side away from the first prism unit 2. The second surface 602 of the second lens unit is the surface on the side closer to the first prism unit 2, and the gap between the first surface 601 of the second lens unit and the first surface 201 of the first prism unit is 0.05 mm to 3.0 mm.

[0118] In an embodiment where a second lens unit 6 is provided between the image source 1 and the first surface 201 of the first prism unit, the refractive power can be changed by moving the image source 1 relative to the first prism unit 2 and changing the distance between them. Furthermore, the refractive power can also be changed by moving the second lens unit 6 relative to the first prism unit 2, or by moving the image source 1 and the second lens unit 6 synchronously. This embodiment is not limited to these methods.

[0119] As mentioned above, the second lens unit 6 can correct aberrations and play a role in refractive dispersion. By adding the second lens unit 6, image quality is improved and optical distortion can be reduced.

[0120] In this embodiment, if the positions of the three optical elements, the first prism unit 2, the second prism unit 3, and the first lens unit 4, are fixed, then if the second lens unit 6 is not provided, or if the position of the second lens unit 6 is fixed, the only way to change the refractive power of the entire optical display device is to adjust the refractive power by moving the image source 1. However, by providing a movable second lens unit 6, the refractive power can be adjusted or adapted by moving the relatively small image source 1 and / or the second lens unit 6.

[0121] Of course, different effects are obtained when only one of the image source 1 or the second lens unit 6 is moved compared to when both the image source 1 and the second lens unit 6 are moved. When only one of the image source 1 or the second lens unit 6 is moved, the drive structure is simpler, requiring only one corresponding drive component. However, this results in significant image distortion, a relatively large reduction in the field of view (FOV), and the edges of the image may not be displayed completely and sharply.

[0122] When both the image source 1 and the second lens unit 6 are moved, the requirements for relative stability during their movement are higher, as are the requirements for the stability and precision of the drive components. Since the second lens unit 6 shares the refraction, the angle of light transmitted from the image source 1 through the second lens unit 6 remains constant throughout, reducing image distortion and field of view (FOV) reduction during the movement process. This ensures higher image quality during the refractive power adjustment process.

[0123] In an embodiment of this application in which a third lens unit 7 is provided on the second surface 302 side of the second prism unit, the third lens unit 7 can be a lens that satisfies a focal length f3 of f3≧50mm or f3≦-50mm, a refractive index of 1.45~1.90, an Abbe number of 35.0~85.0, a radius of curvature R31 of the first surface 701 of R31≧100mm or R31≦-100mm, and a radius of curvature R32 of the second surface 702 of R32≧100mm or R32≦-100mm. Of these, the first surface 701 of the third lens unit is the surface on the side closer to the body of the second prism unit 3, and the second surface 702 of the third lens unit is the surface on the side further away from the body of the second prism unit 3.

[0124] In an optical display device including a third lens unit 7, the refractive power of the entire optical display device can be changed by moving the third lens unit 7 relative to the second surface 302 of the second prism unit and changing the distance between them.

[0125] In the embodiment described above in which the image source 1 and / or the second lens unit 6 are moved, the refractive power can be adjusted only with respect to the projected image light from the image source 1, and no adjustment is made to the refractive power with respect to the ambient light seen by the human eye 11.

[0126] However, in the case of an optical display device equipped with a third lens unit 7, not only does the projected image light from the image source 1 pass through the third lens unit 7 before entering the human eye 11, but ambient light also passes through the third lens unit 7 before entering the human eye 11. Therefore, by moving the third lens unit 7, it is possible to adjust the refractive power not only for the projected light entering the human eye 11, but also for the ambient light. This allows the wearer to simultaneously view the screen of the surrounding environment and the projected screen formed by the projected light output by the image source 1, thereby achieving a better fusion of virtual and reality. This avoids the frequent adjustment of the lens that is required when switching between viewing the projected screen and the screen of the surrounding environment, thus avoiding eye strain and discomfort.

[0127] As shown in Table 2, Table 2 shows a set of parameters corresponding to each optical element in the embodiment shown in Figure 1.

[0128] [Table 2]

[0129] In the optical display device constructed according to Table 2, the geometric point diffusion function in each field of view is approximately 50 μm, the maximum distortion of the projected image is approximately 14.0%, the MTF of each field of view is within 24 lp / mm and exceeds 0.1, the relative contrast of the entire image plane exceeds 80%, and the illumination is uniform. Therefore, the optical display device has excellent image formation quality.

[0130] As shown in Table 3, Table 3 shows a set of parameters corresponding to each optical element in the embodiment shown in Figure 5.

[0131] [Table 3]

[0132] In the optical display device configured according to Table 3, the geometric point diffusion function in each field of view is less than 50 μm, the maximum distortion of the projection screen is approximately 9.5%, the overall distortion is small, the MTF of each field of view of the imaging system is within 30 lp / mm and exceeds 0.1, the relative contrast of the entire image plane of the imaging system exceeds 80%, and the illumination is uniform.

[0133] As shown in Table 4,

[0134] [Table 4]

[0135] In the optical display device configured according to Table 4, the geometric point diffusion function in each field of view is less than 50 μm, the maximum distortion of the projection screen is approximately 14.0%, the MTF of each field of view of the imaging system is within 30 lp / mm and exceeds 0.1, the relative contrast of the entire image plane of the imaging system exceeds 80%, and the illumination is uniform.

[0136] In summary, in this application, the cooperation of the first prism unit 2, the second prism unit 3, and the first lens unit 4 allows the transmission path of the projected light to be repeatedly folded within the first prism unit 2, providing the projected light with a sufficiently large transmission path length. Furthermore, the projected light only needs to be reflected twice within the first prism unit 2, ensuring a sufficient optical path length for the projected light while avoiding the problem of the first prism unit 2 becoming excessively large due to too many reflections, thus contributing to the overall weight reduction of the display device. In addition, the first surface 201 of the first prism unit is located on the side closer to the wearer's eye 11, and the image source 1 emits projected light toward the first surface 201 of the first prism unit. Therefore, the image source 1 can be installed on the side of the first prism unit 2 closer to the wearer's head, making the installation of the image source 1 easier and simplifying the installation structure of the image source 1. The optical display device provided in this application has a simple structure and a relatively small overall size, making it advantageous for a wide range of applications.

[0137] Another embodiment of the present disclosure further discloses an embodiment of an optical display device, as shown in Figures 5 to 11, which includes an image source 1, a first prism unit 2, a second prism unit 3, and a first lens unit 4.

[0138] Of these, the image source 1 is installed on the first surface 201 side of the first prism unit, and the first lens unit 4 is installed in contact with the second surface 202 of the first prism unit. The first surface of the second prism unit 3 is installed in contact with the third surface 203 of the first prism unit. The first surface 201 and the third surface 203 of the first prism unit are located closer to the wearer's eye than the second surface 202 of the first prism unit, and a first semi-transparent semi-reflective film is provided on the surface of the first lens unit 4 that is further away from the first prism unit 2.

[0139] The projected light emitted from image source 1 enters the first prism unit 2 via the first surface 201 of the first prism unit, then undergoes total internal reflection by the second surface 202 of the first prism unit, reflection by the third surface 203 of the first prism unit, and transmission by the second surface 202 of the first prism unit before entering the first lens unit 4. After being reflected by the first semi-transparent semi-reflective film, it then passes through the second surface 202, the third surface 203, and the second prism unit 3 of the first prism unit in order before entering the human eye 11.

[0140] In addition to the above, the optical display device provided in this embodiment further includes a film system unit, which is used to reflect all or part of the light emitted from the image source 1 and cause it to enter the first lens unit 4, and to transmit the light that has returned to the first prism unit 2 by reflection by the first lens unit 4.

[0141] The film system unit is installed between the third surface 203 of the first prism unit and the first surface of the second prism unit 3.

[0142] The first surface 201 of the first prism unit is spherical or aspherical, and the surface of the first lens unit 4 is any combination of spherical, aspherical, free-form, Fresnel, and planar surfaces.

[0143] Image source 1 can be adjusted in refractive power by moving relative to the first surface 201 of the first prism unit, and the focal length of the first surface 201 of the first prism unit is 25mm to 200mm.

[0144] As shown in Figure 8, the solid line frame A represents image source 1 at a refractive index of 0D, and the dashed line frame B represents image source 1 at a refractive index of -7D. Image source 1 is one of an OLED display, LCOS display, MicroLED display, DLP display, or LBS display, and is preferably an OLED display.

[0145] The second prism unit 3 is a prism having an aberration correction function and optical path difference compensation in the upper and lower fields of view. The prism may be made of plastic or glass, and its quantity is not limited. The surface shape includes, but is not limited to, spherical lenses, aspherical lenses, free-form lenses, Fresnel lenses, and planar lenses. A spherical lens is preferred.

[0146] The first prism unit 2 includes the first prism unit 2 and a film system unit. The first prism unit 2 may be made of plastic or glass. The film system unit is placed between the third optical surface of the first prism unit 2 and the first surface of the second prism unit 3. The film system unit can be attached to the first prism unit 2 or the second prism unit 3, or it can be coated onto the first prism unit 2 or the second prism unit 3. The film system unit reflects (or partially reflects) the light emitted from the image source 1 when it first reaches the third optical surface of the first prism unit 2, while transmitting the light reflected from the first lens unit 4 to the first prism unit 2.

[0147] The first lens unit 4 is composed of a series of lenses having aberration correction and optical path reflection functions. The material of each lens may be glass or plastic, and includes, but is not limited to, spherical lenses, aspherical lenses, free-form lenses, Fresnel lenses, and planar lenses. Preferably, it is a spherical lens. A first semi-transparent semi-reflective film is provided on the side away from the first prism unit 2. This first semi-transparent semi-reflective film can be realized by a coating method or a film bonding method.

[0148] This refractive power adjustable near-eye display device may further include an aperture. The aperture may be located between the second prism unit 3 and the human eye 11, or at the position of the human eye 11.

[0149] The focal length range of the first surface 201 of the first prism unit is 25mm to 200mm, and the refractive power can be adjusted by combining this with the movement of the image source 1. For example, the distance between the image source 1 and the first surface 201 of the first prism unit is 0.25mm to 3.0mm. That is, as the image source 1 gradually moves closer to the first prism unit 2, the distance between the image source 1 and the first surface 201 of the first prism unit gradually decreases, and the refractive power can be adjusted from 0D to -7D. As the image source 1 gradually moves further away from the first prism unit 2, the distance between the image source 1 and the first surface 201 of the first prism unit gradually increases, and the refractive power can be adjusted from -7D to 0D.

[0150] If the focal length of the first surface 201 of the first prism unit is not within this range, the image quality in a part of the field of view may deteriorate during the focusing process, such as unevenness (non-uniformity) of the screen, reduced sharpness at the edges, and rectangular distortion of the screen. At the same time, the change in the field of view angle may be relatively large (approximately 3°) within the range of 0D to -7D. Therefore, users with a relatively large difference in visual acuity between their two eyes may experience a relatively large difference in the clarity and screen size of the image seen by both eyes, making it difficult to fuse the images of both eyes and resulting in a poor wearing and viewing experience.

[0151] The angle between the first surface 201 and the second surface of the first prism unit is preferably 15° to 35°. If the angle is too small, the requirement that the light emitted from the image source 1 be reflected multiple times by traveling back and forth within the first prism unit 2, or that the light emitted from the image source 1 be totally reflected on the first prism unit 2, cannot be met. If the angle is too large, the light emitted from the image source 1 will only be reflected once within the first prism unit 2 before being emitted again, and the requirement that the light path be folded back by being reflected twice within the first prism unit 2 cannot be met. Therefore, having the angle within this range fulfills the requirement that the light emitted from the image source 1 be reflected twice within the first prism unit 2, contributing to the realization of a small and lightweight near-eye display device. Furthermore, in this embodiment, the first surface 201 of the first prism unit is preferably positioned at an angle toward the human eye 11.

[0152] During operation, light emitted from image source 1 passes through the first surface 201 of the first prism unit and enters the first prism unit 2. The first reflection occurs at the second surface 202 of the first prism unit, and the light is reflected again to the third surface 203 of the first prism unit. The film system unit is placed between the third surface 203 of the first prism unit and the second prism unit 3. The light is reflected a second time at the third surface of the first prism unit 2, passes through the second surface 202 of the first prism unit, and enters the first lens unit 4. A first semi-transparent, semi-reflective film is provided on the first lens unit 4, reflecting the light back to the first prism unit 2. Then, the light passes sequentially through the first prism unit 2 and the second prism unit 3 before entering the human eye 11 and forming an image. The refractive power can be adjusted by adjusting the distance between image source 1 and the first surface 201 of the first prism unit. In other words, by adjusting the position of image source 1 and combining it with the surface shape of the first surface 201 of the first prism unit, and rationally setting the focal length range of the first surface 201 of the first prism unit, it is possible to realize a virtual image distance (refractive power) adjustment function, while maintaining relatively high image quality and relatively small field of view angle changes within the adjustment range. For example, the virtual image distance adjustment range is 5000 mm to 142 mm, the refractive power can be adjusted from 0 D to -7 D, and relatively high image quality can be maintained. Furthermore, within the virtual image distance adjustment range of 0 D to -7 D, the change in field of view angle can be kept within 0.8°, and even when the difference in refractive power between the two eyes is relatively large, the images seen by each eye have relatively good agreement, and a relatively excellent binocular fusion effect can be obtained.

[0153] In one embodiment, a fourth lens unit 8 is further included. The fourth lens unit 8 is installed near the first semi-transparent semi-reflective film, and the focal length of the fourth lens unit 8 and the focal length of the first lens unit 4 are inversely proportional (opposite signs).

[0154] Of these, the fourth lens unit 8 is composed of a series of lenses with aberration correction functions, correcting aberrations that occur when the human eye 11 looks at the surroundings through the first lens unit 4, and ensuring that the aberrations of the surroundings seen by the human eye 11 are sufficiently small. The lenses constituting the fourth lens unit 8 can be made of plastic or glass material, and the number of lenses is not limited. The surface shape includes, but is not limited to, spherical lenses, aspherical lenses, free-form surface lenses, Fresnel lenses, and planar lenses. Preferably, it is a spherical lens.

[0155] In one embodiment, the focal length of the first lens unit 4 is 10-25 mm. This is suitable for a wide field of view and screen size, and contributes to suppressing distortion.

[0156] In one embodiment, the film system unit includes at least one of a third semitransmissive semi-reflective film, a reflective polarizing film, a quarter-wave plate, and an absorbing polarizing film.

[0157] The film system unit can be a reflective polarizing film. Alternatively, the film system unit can be a combination of a reflective polarizing film and a quarter-wave plate. In this case, the quarter-wave plate can be positioned between the reflective polarizing film and the first prism unit 2. Alternatively, the film system unit may be a semi-transparent, semi-reflective film, and can be specifically adjusted according to actual requirements.

[0158] Preferably, the ratio of transmittance to reflectance of each semi-transparent, semi-reflective film is 1:9 to 9:1. The semi-transparent, semi-reflective film has the function of partially reflecting and partially transmitting light, and its ratio of reflection to transmission can be set by comprehensively considering factors such as the angle of incident light, the brightness of image source 1, and the brightness of the external environment.

[0159] In one embodiment, the distance between the image source 1 and the first surface 201 of the first prism unit is preferably 0.25 mm to 3.0 mm.

[0160] If the movement range of image source 1 is insufficient, the final adjustment range of the virtual image distance (0D to -7D) may be insufficient. By selecting the distance between image source 1 and the first surface 201 of the first prism unit to fall within this range, a relatively large refractive power adjustment range can be obtained, making it suitable for a wider range of users.

[0161] Beyond this distance range, controlling the distortion of the output image becomes difficult, failing to meet the imaging requirements. Furthermore, the change in FOV (field of view) becomes relatively large, making it difficult to meet the requirements for binocular fusion within the refractive power adjustment range.

[0162] In another embodiment, the optical display device further satisfies the following conditions.

[0163] R1 ≤ -100mm or R1 ≥ 100mm

[0164] -40mm ≤ R2 ≤ -100mm,

[0165] R3 ≤ -200mm or R3 ≥ 18mm.

[0166] Of these, R1 represents the radius of curvature of the lens surface on the first lens unit 4 that is close to the fourth lens unit 8, R2 represents the radius of curvature of the side of the first lens unit 4 that is farther from the fourth lens unit 8, and R3 represents the radius of curvature of the first surface 201 of the first prism unit.

[0167] Preferably, the aspherical shape is as follows:

[0168]

number

[0169] In the above embodiment, if any of the surfaces have an even-order aspherical shape, the above formula must be satisfied.

[0170] The following will provide a detailed explanation using specific examples.

[0171] In this embodiment, the objective of adjusting the virtual image distance (refractive power) is achieved by adjusting the position of the image source 1 based on a prism total internal reflection structure and combining it with the surface shape of the first surface 201 of the first prism unit. Of these, the first surface 201 of the first prism unit is aspherical, the first lens unit 4 is a biconvex aspherical lens, and the fourth lens unit 8 is a biconcave spherical lens. The refractive indices of the first prism unit 2 and the second prism unit 3 are 1.45 to 1.75, and the Abbe number is 18.0 to 60.0. The refractive index of the first lens unit 4 is 1.45 to 1.90, and the Abbe number is 35.0 to 85.0. The focal length of the first surface 201 of the first prism unit is 170 mm. The image source 1 is movable relative to the first surface 201 of the first prism unit, and the distance between the image source 1 and the first surface 201 of the first prism unit is 0.25 mm to 3.0 mm.

[0172] The aspherical parameters are shown in Table 5.

[0173] [Table 5]

[0174] Of these, R is the radius of curvature (in mm), Len1_S1 is the lens surface on the first lens unit 4 that is close to the fourth lens unit 8, Len1_S2 is the lens surface on the first lens unit 4 that is far from the fourth lens unit 8, and P2_S3 is the first surface 201 of the first prism unit.

[0175] The refractive power adjustment parameters are shown in Table 6.

[0176] [Table 6]

[0177] Based on the above data, as shown in Figures 9 to 14, the near-eye display device of this embodiment has an MTF value of 0.15 or higher at 30 lp / mm when the refractive power is 0D, -3D, and 7D, indicating relatively high imaging quality. Furthermore, the spot diagram shows that the near-eye display device displays a high-resolution and clear image, meaning that the imaging quality of the near-eye display device is good and does not deteriorate significantly during the adjustment process from 0D to -7D.

[0178] In the above embodiment, refractive power adjustment is achieved without adding any additional components by adjusting the distance between the image source 1 and the first surface 201 of the first prism unit. That is, by adjusting the position of the image source 1 and combining the surface shape of the first surface 201 of the first prism unit to appropriately set the focal length range of the first surface 201 of the first prism unit, a virtual image distance (refractive power) adjustment function can be realized. Furthermore, relatively high image quality and small field of view angle changes can be maintained within the adjustment range. For example, by setting the virtual image distance adjustment range to 5000 mm to 142 mm and adjusting the refractive power in the range of 0 D to -7 D, high image quality can be maintained. In addition, within the virtual image distance adjustment range of 0 D to -7 D, the change in the field of view can be controlled to within 0.8°, and even when the difference in refractive power is large within the adjustment range, both eyes have a good binocular image fusion effect. Furthermore, since the near-eye display device can achieve optical path folding, it is even more advantageous in achieving miniaturization and weight reduction while ensuring sufficient optical path length for imaging light.

[0179] In one embodiment, as shown in Figures 15-17, the optical display device may include an image source 1, a first prism unit 2, a second prism unit 3, and a first lens unit 4.

[0180] Of these, image source 1 is installed on the first surface 201 side of the first prism unit, and the first lens unit 4 is installed in contact with the second surface 202 of the first prism unit. The first surface of the second prism unit 3 is installed in contact with the third surface 203 of the first prism unit, and the first surface 201 and third surface 203 of the first prism unit are closer to the wearer's eye than the second surface 202 of the first prism unit, and the surface of the first lens unit 4 that is further away from the first prism unit 2 has a first semi-transparent semi-reflective film installed.

[0181] The projected light emitted from image source 1 passes through the first surface 201 of the first prism unit and enters the first prism unit 2. It then undergoes total internal reflection by the second surface 202 of the first prism unit, reflection by the third surface 203 of the first prism unit, and passage through the second surface 202 of the first prism unit before entering the first lens unit 4. After being reflected by the first semi-transparent semi-reflective film, it is then transmitted through the second surface 202 and third surface 203 of the first prism unit and the second prism unit 3 before being emitted and entering the human eye 11.

[0182] Furthermore, in addition to the above, it also includes a first polarization unit 9, which is installed between the first prism unit 2 and the second prism unit 3. The first polarization unit 9 is used to reflect the imaging light in the first polarization transmission direction to the first lens unit 4 and to transmit the imaging light in the second polarization transmission direction. Moreover, the first polarization transmission direction and the second polarization transmission direction are 90° apart, and the first polarization transmission direction is the same as the polarization transmission direction of the image source 1. The first semi-transparent semi-reflective film is used to reflect the imaging light in the first polarization transmission direction, and then, after passing through the first prism unit 2 and the second prism unit 3, to the human eye 11, and also to transmit real-world light, and then, after passing through the first prism unit 2 and the second prism unit 3, to the human eye 11.

[0183] A second polarization unit 10 is attached to the second surface 302 of the second prism unit. The second polarization unit 10 is expected to transmit light parallel to the third polarization transmission direction and reflect light perpendicular to the third polarization transmission direction. The third polarization transmission direction is the same as the second polarization transmission direction.

[0184] Of these, image source 1 is used to emit image light and is, for example, one of OLED displays, LCOS displays, MicroLED displays, DLP displays, or LBS displays, preferably an OLED display. Image source 1 includes, but is not limited to, the above devices. The first prism unit 2 and the second prism unit 3 can be of any shape, but are preferably triangular prisms or square prisms.

[0185] The first lens unit 4 is a group of lenses having aberration correction and optical path reflection functions. The material of the lens group may be glass or plastic, and includes, but is not limited to, spherical lenses, aspherical lenses, free-form lenses, Fresnel lenses, and planar lenses. Preferably, it is a spherical lens. The semi-transparent, semi-reflective film can be realized by a coating method or a film bonding method.

[0186] The first prism unit 2 is used to reflect the image light to the first polarization unit 9, utilizing the principle of total internal reflection at the air interface.

[0187] The first polarization unit 9 is used to reflect image light in the first polarization transmission direction and transmit image light in the second polarization transmission direction. For example, the first polarization transmission direction is 45° and the second polarization transmission direction is -45°. The image light reflected by the first polarization unit 9 is further reflected by the semi-transparent semi-reflective film on the first lens unit 4, then passes through the first prism unit 2 to reach the first polarization unit 9, where it is converted before entering the human eye 11.

[0188] In conventional technology, reflection inevitably occurs on the lens surface closer to the human eye 11, resulting in cheek reflection (in Figure 16, the thick horizontal arrow pointing to the right indicates that stray light from an external source is incident on the second prism, and the thin arrow indicates that stray light from an external source has been filtered), causing stray light and double images (ghost images). This optical module adds a second polarization unit 10 on the eye-incident side. The second polarization unit 10 transmits all light parallel to the third polarization transmission direction and reflects all light perpendicular to the third polarization transmission direction. As a result, 50% of the stray light from the outside is first blocked, that is, all light perpendicular to the third polarization transmission direction is reflected. Furthermore, 50% of the stray light from the outside is transmitted because it is parallel to the third polarization transmission direction, but its energy is much lower than the image light emitted from the image source 1, so it is completely masked (covered). This eliminates problems such as stray light and double images in the image, avoids halos, glare, eye strain, and discomfort caused by interference and light pollution from cheek reflections, and does not affect the user's perception or cognition of the virtual image. This improves the user experience and comfort. Furthermore, the optical module increases the field of view by folding the optical path multiple times (three reflections), contributing to a lighter and thinner design.

[0189] Preferably, the first polarization unit 9 includes a first linear polarizer 91, a polarizing reflector 92, and a second quarter-wave plate 93, which are sequentially installed along the direction from the second prism unit 3 toward the first prism unit 2.

[0190] Of these, the first linear polarizer 91 has the function of selecting the direction of vibration of light, and mainly transmits light in a specific direction and blocks light in other directions based on the polarization state of the light. For example, in this embodiment, it transmits linearly polarized light at -45° and does not transmit linearly polarized light at 45°.

[0191] The polarizing reflector 92 has the ability to selectively reflect or transmit light of a specific polarization direction. Its polarizing reflectivity is achieved by alternately stacking multiple layers of material. In practical applications, the reflectivity for different polarization states can be controlled by adjusting the thickness and composition of the film layers, thereby allowing for precise control of light.

[0192] The second quarter-wave plate 93 is used to change the polarization state of the polarization. It mainly converts linearly polarized light to circularly polarized light, or circularly polarized light to linearly polarized light. The quarter-wave plate is usually used in combination with other polarizing elements (e.g., linear polarizer, polarizing reflector 92, etc.) to achieve complex optical control and adjustment.

[0193] In another embodiment, the image source 1 is further provided with a third polarization unit 12, which is used to convert the image light into 45° linearly polarized light.

[0194] The third polarization unit 12 is installed on the light emission side of the image source 1 and can be attached to the image source 1. The third polarization unit 12 is used to convert the image light into 45° linearly polarized light so that the first polarization unit 9 can reflect the image light.

[0195] Preferably, the second polarizing unit 10 includes a second linear polarizer, and the third polarizing unit 12 includes a third linear polarizer.

[0196] The second polarization unit 10 uses a second linear polarizer to transmit light parallel to the third polarization transmission direction and reflect light perpendicular to the third polarization transmission direction. The third polarization unit 12 uses a third linear polarizer to convert the image light. For example, if the third linear polarizer is a 45° linear polarizer, 45° linearly polarized light is emitted.

[0197] In one embodiment, 45° linearly polarized light undergoes its first reflection on the side of the first prism unit 2 closest to the first lens unit 4, forming the first ray. The first ray undergoes a second reflection on the first polarization unit 9, forming the second ray. The second ray undergoes a third reflection on the first semi-transparent semi-reflective film, forming the third ray. The third ray is converted into the fourth ray by the first polarization unit 9, and the fourth ray passes through the second polarization unit 10 and enters the human eye 11. The first ray is 45° linearly polarized, the second ray is left-handed circularly polarized, the third ray is right-handed circularly polarized, and the fourth ray is -45° linearly polarized. The second polarization unit 10 transmits -45° linearly polarized light and reflects 45° linearly polarized light. It is easily understood that the specific type and direction of light can be adjusted according to actual requirements to satisfy practical use.

[0198] Preferably, the first lens unit 4 is a curved lens, with the side closer to the first prism unit 2 being flat and the side further away from the first prism unit 2 being convex. The curved lens is a lens equipped with aberration correction and optical path reflection functions. The material of the lens can be glass or plastic. It is easily understood that the number of lenses and the surface shape of the lenses in the first lens unit 4 can be adjusted according to actual requirements.

[0199] In one embodiment, the image source 1 is movable relative to the first prism unit 2. By moving the image source 1, the virtual image distance of the final output virtual image can be changed, thereby adapting to viewing use by users with different visual acuity.

[0200] In one embodiment, a fifth lens unit 13 is further included. The fifth lens unit 13 is installed between the image source 1 and the first prism unit 2, and the fifth lens unit 13 includes at least one lens.

[0201] The focal length of the fifth lens unit 13 is preferably 5mm to 50mm, which is advantageous for improving image quality. Because the fifth lens unit 13 with a positive focal length is added, the image light is constrained and focused before it enters the first prism unit 2. Therefore, the angle of reference and the amount of movement required for refractive power adjustment are smaller than in a method that moves only the image source 1.

[0202] Preferably, the refractive power can be adjusted by synchronously moving the fifth lens unit 13 and the image source 1 relative to the first prism unit 2.

[0203] Specifically, for the integrity of the final image and excellent image quality, the synchronization direction of the fifth lens unit 13 and the image source 1 can be kept constant with respect to the optical axis direction of the image source 1. That is, during movement, there is a movement component parallel to the light-emitting surface of the image source 1, so that the image light emitted by the image source 1 throughout its entire movement range is properly incident on the first prism unit 2 and light transmission occurs, ensuring that there are no defects in the final image within the refractive power adjustment range. Furthermore, the entire light-emitting surface of the image source 1 can be fully utilized, enabling refractive power adjustment from 0D to 6D.

[0204] Furthermore, by synchronously moving the image source 1 and the fifth lens unit 13, the angle of light emitted from the same position on the image source 1 after passing through the fifth lens unit 13 is the same during the movement process. In other words, the degree of divergence of light emitted from the fifth lens unit 13 is kept constant at different refractive indices, thereby maintaining a constant field of view (FOV) at the final image formation, and preventing significant reduction in size.

[0205] The operating principle of the above embodiment is as follows.

[0206] Operating principle:

[0207] Image source 1 emits image light, which is converted to 45° linearly polarized light (with the polarization transmission direction perpendicular to the paper plane and towards the back) by the third polarization unit 12. The 45° linearly polarized light passes through the fifth lens unit 13 and then undergoes its first reflection on the side of the first prism unit 2 closest to the first lens unit 4. After the first reflection, the 45° linearly polarized light undergoes a second reflection on the first polarization unit 9, becoming left-handed circularly polarized light. The left-handed circularly polarized light undergoes a third reflection on the semi-transparent semi-reflective film, becoming right-handed circularly polarized light. The right-handed circularly polarized light passes through the first polarization unit 9 again, is converted to -45° linearly polarized light by the second quarter-wave plate 93, and then passes through the second polarization unit 10 before entering the human eye 11. The first polarization unit 9 transmits -45° linearly polarized light and reflects 45° linearly polarized light, thereby achieving a direct conversion between linearly polarized and circularly polarized light. Furthermore, by combining it with a deposited semi-transparent semi-reflective film, the polarization state of the circularly polarized light can be converted.

[0208] The second polarization unit 10 is used to transmit -45° linearly polarized light and reflect 45° linearly polarized light, effectively directing the imaging light to the human eye 11. At the same time, due to the optical selectivity of the second polarization unit 10, 50% of external stray light can be directly removed, and the remaining 50% of external stray light is coupled to the region with the strongest energy in the imaging system, i.e., the image light emitted from the image source 1, and is therefore completely shielded (masked), having little impact on the user experience. Figure 17 shows the configuration of each polarization unit. Note that, for the sake of ease of understanding, the relative positions of each polarization unit in the figure are not set to strictly match the actual corresponding arrangement.

[0209] In one embodiment, as shown in Figures 18-29, the optical display device may include an image source 1, a first prism unit 2, a second prism unit 3, and a first lens unit 4.

[0210] Of these, the image source 1 is installed on the first surface 201 side of the first prism unit, and the first lens unit 4 is installed in contact with the second surface 202 of the first prism unit. The first surface of the second prism unit 3 is installed in contact with the third surface 203 of the first prism unit, and the first surface 201 and the third surface 203 of the first prism unit are closer to the wearer's eye than the second surface 202 of the first prism unit, and the surface of the first lens unit 4 that is away from the first prism unit 2 is provided with a first semi-transparent semi-reflective film.

[0211] The projected light emitted from image source 1 passes through the first surface 201 of the first prism unit, enters the first prism unit 2, then sequentially undergoes total internal reflection by the second surface 202 of the first prism unit, reflection by the third surface 203 of the first prism unit, and transmission by the second surface 202 of the first prism unit before entering the first lens unit 4, where it is reflected by the first semi-transparent semi-reflective film, and then sequentially passes through the second surface 202, third surface 203, and second prism unit 3 of the first prism unit before being emitted and entering the human eye 11.

[0212] In addition to the above, this embodiment further includes a polarization conversion unit.

[0213] A linear polarizing film is provided on the light emission side of image source 1.

[0214] Furthermore, it is equipped with a film system unit, which includes a polarizing reflective unit and is attached to the third surface 203 of the first prism unit.

[0215] The polarization conversion unit is installed between the first prism unit 2 and the first lens unit 4, or between the polarization reflection unit and the first prism unit 2.

[0216] The thickness of the linear polarizing film is 60 nm to 250 nm, the thickness of the film system unit is 90 nm to 280 nm, the thickness of the polarization conversion unit is 30 nm to 100 nm, and the thickness of the semi-transparent, semi-reflective film is 50 nm to 300 nm.

[0217] The imaging light emitted from image source 1 is converted into linearly polarized light by a linearly polarizing film. The linearly polarized light is incident on the first prism unit 2, undergoes total internal reflection, and then reaches the film system unit. Further reflected by the film system unit, it reaches the first lens unit 4, is reflected by the first semi-transparent semi-reflective film on the first lens unit 4 and returns to the first prism unit 2, and then sequentially passes through the film system unit and the second prism unit 3 to reach the human eye 11 and form an image.

[0218] Of these, image source 1 is used to provide an image screen. The first prism unit 2 can be made of plastic or glass. The film system unit can be attached to the first prism unit 2 or coated on the first prism unit 2. The film system unit has a light polarization reflection function. The second prism unit 3 includes a second prism and is installed near the film system unit; for example, the second prism unit 3 is located between the first prism unit 2 and the human eye 11. The polarization conversion unit can be installed between the first prism unit 2 and the first lens unit 4, or between the polarization reflection unit and the first prism unit 2, and can be installed according to actual requirements.

[0219] The first lens unit 4 is a group of lenses equipped with aberration correction and optical path reflection functions. The material of the lens group can be glass or plastic, and examples include, but are not limited to, spherical lenses, aspherical lenses, free-form lenses, Fresnel lenses, and planar lenses. Preferably, it is a spherical lens. For example, if the first lens unit 4 is a curved lens, a first semi-transparent semi-reflective film is provided on the inside of the curved lens (the side closer to the first prism unit 2). This semi-transparent semi-reflective film can be realized by a coating method or a bonding method.

[0220] By rationally setting the thickness of the linear polarizing film, film system unit, polarization conversion unit, and semi-transmissive semi-reflective film, the transmission and reflection effect is guaranteed, while also ensuring the feasibility of the film material process, resulting in a good balance between image quality and reliability. Specifically, this is as follows:

[0221] 1) If a linear polarizing film is too thin, problems such as unstable optical performance, reduced polarization effect, and inability to mold can occur. At the same time, it becomes more susceptible to external environmental influences such as mechanical damage and chemical corrosion, which reduces its durability. On the other hand, a linear polarizing film that is too thick increases reflectivity and thus increases light loss, which also affects the polarization effect, reducing optical performance and increasing the risk of ghosting.

[0222] 2) The polarizing reflective unit of the film system unit is a thin film material that reflects light by utilizing its polarization properties. If the polarizing reflective unit material is too thin, the following problems occur: 1. It becomes difficult to mold, and is more brittle and easily deformed, negatively affecting the polarization effect. 2. Reduced durability: Polarizing reflective unit material that is too thin is relatively brittle and easily damaged by abrasion or scratches. If the material of the polarizing reflective unit is too thick, it leads to a decrease in optical performance. Transmittance and polarization rate decrease, affecting the application effect as an optical element, and making ghost images more likely to occur.

[0223] 3) Polarization conversion units (e.g., quarter-wave plates) are optical devices used to adjust the polarization state and change the phase of light. If a polarization conversion unit is too thin, it is difficult to mold and prone to cracking. If it is too thick, the optical path length difference changes. Since the thickness of a polarization conversion unit is designed based on wavelength, if it is too thick, the change in optical path length difference exceeds the design value, thereby affecting its ability to adjust the polarization state and phase of light.

[0224] 4) When a semi-transparent, semi-reflective film is deposited using vapor deposition, if the film is too thin, deposition becomes difficult and uniformity of the film thickness cannot be guaranteed. If it is too thick, there is a risk of the film layer delaminating. If it is too thin or too thick, it becomes difficult to ensure imaging effect and stability.

[0225] This optical display device achieves an expanded field of view (FOV) and a lighter, thinner design through three reflections and multiple optical path folding. Specifically, the first reflection utilizes total internal reflection in air (i.e., an air gap exists between the first prism unit 2 and the first lens unit 4, and since the refractive index of air is lower than that of the first prism unit 2 and the first lens unit 4, the image-forming light is totally reflected at the surface of the first prism unit 2 closest to the first lens unit 4). The second reflection occurs when linearly polarized light converted by a linear polarizing film is incident on the film system unit and reflected. The third reflection occurs when light is reflected by a semi-transparent, semi-reflective film. For example, the field of view (FOV) has increased from 48° in the conventional birdbath system to over 60°, and the thickness has been reduced to half of the 18mm-20mm of the conventional birdbath system.

[0226] In one embodiment, the polarization conversion unit is a quarter-wave plate 5, and the angle between the reflection axis of the film system unit and the retard axis of the polarization conversion unit is 45°±1°.

[0227] To ensure the imaging effect, the film unit and the polarization conversion unit maintain a specific angular relationship. The retard axis of the polarization conversion unit must be attached at a 45° angle to the reflection axis of the film unit, with a tolerance of ±1°. This ensures that linearly polarized light is converted to standard circularly polarized light.

[0228] In another embodiment, the film system unit further includes a polarization absorption unit, the polarization absorption unit being a polarization absorption film, the polarization absorption film being positioned between the polarization reflection unit and the second prism unit 3, and the absorption axis of the polarization absorption unit being parallel to the reflection axis of the polarization reflection unit.

[0229] The reflection axis of the polarization reflection unit (e.g., a polarization reflection film) and the absorption axis of the polarization absorption unit (e.g., a polarization absorption film) must be parallel, which is advantageous for eliminating double images. That is, the polarization conversion unit, the polarization reflection unit, and the polarization absorption unit are installed sequentially along a direction close to the human eye 11.

[0230] In one embodiment, the image source 1 is movable relative to the first prism unit 2, and the movement distance is less than 5 mm.

[0231] By moving image source 1, the final virtual image distance can be changed, thereby meeting the viewing needs of people with different visual acuity.

[0232] Preferably, the angle between the direction of movement of the image source 1 relative to the first prism unit 2 and the optical axis direction of the image source 1 is 0° to 15°.

[0233] In actual use, if the image source 1 is too large, when the image source 1 moves to the edge of the range, due to the limitations of the optical lens or the like, the display content at the edge of the light-emitting surface of the image source 1 cannot normally enter the first prism unit 2 and be guided, which may cause a missing part in the finally viewed image. Therefore, it is set so that the moving direction of the image source 1 and the optical axis direction present a certain included angle, that is, it has a moving component parallel to the light-emitting surface of the image source 1 during movement, and all the imaging light emitted by the image source 1 over the entire moving range can normally enter the first prism unit 2 and conduct light transmission, within the refractive power adjustment range, ensuring that the final imaging screen is complete without missing parts and that the entire light-emitting surface of the image source 1 can be fully utilized. However, this angle must not be too large. When the image source 1 moves, the moving component parallel to the light-emitting surface of the image source 1 must be relatively small, and the main moving component of the image source 1 must be in the optical axis direction. If the angle is too large, when the image source 1 moves, the moving component parallel to the light-emitting surface of the image source 1 becomes too large, and within the entire refractive power adjustment range, all the imaging light emitted from the image source 1 can enter the first prism unit 2, and it is necessary to make the incident surface of the first prism unit 2 very large, and the volume of the entire device also becomes very large, and the volume of the applied extended reality device is also relatively large, making it difficult to meet the requirement of being lightweight and thin.

[0234] In this embodiment, the included angle is preferably 7°, whereby while ensuring lightweight and thinness, the integrity of the display screen can be ensured and the display effect can be guaranteed.

[0235] In another embodiment, it further includes a sixth lens unit 14. The sixth lens unit 14 is installed on the light-emitting side of the image source 1, and linearly polarized light enters the first prism unit 2 through the sixth lens unit 14.

[0236] The focal length of the sixth lens unit 14 is 5 to 50 mm, which is advantageous for improving the imaging quality.

[0237] The image source 1 and the sixth lens unit 14 can further move synchronously with respect to the first prism unit 2, and the moving distance is less than 4 mm. Thereby, the refractive power adjustment from 0D to 6D can be realized.

[0238] The included angle between the direction in which the image source 1 and the sixth lens unit 14 move synchronously with respect to the first prism unit 2 and the optical axis direction of the image source 1 is 0° to 10°. The optical axis direction of the image source 1 is the direction perpendicular to the screen light-emitting surface of the image source 1.

[0239] In actual use, when the image source 1 and the sixth lens unit 14 move synchronously to the endpoints of the range, due to limitations such as optical lenses, the display content on the edge of the light-emitting surface of the image source 1 may not be normally incident on the first prism unit 2 and cannot be light-guided, and there may be missing parts in the finally visible screen. Therefore, the direction of the synchronous movement of the image source 1 and the sixth lens unit 14 and the optical axis direction of the image source 1 form a certain angle, that is, by having a moving component parallel to the light-emitting surface of the image source 1 during movement, all the imaging light emitted by the image source 1 over the entire movement range can be normally incident on the first prism unit 并进行导光, within the refractive power adjustment range, the final imaging screen is complete without missing parts, and the entire light-emitting surface of the image source 1 can be fully utilized. However, this angle should not be too large. When the image source 1 moves, the moving component parallel to the light-emitting surface of the image source 1 should be relatively small, and the main moving component of the image source 1 should be in the optical axis direction. If this angle is too large, that is, when the image source 1 moves, the moving component parallel to the light-emitting surface of the image source 1 becomes too large, in order to ensure that all the imaging light emitted from the image source 1 can be incident on the incident surface of the first prism unit over the refractive power adjustment range, it is necessary to make the incident surface of the first prism unit very large, and the volume of the entire device will also become very large, and it will be difficult to meet the requirements of being lightweight and thin for the extended reality device applied with this.

[0240] Compared to a configuration in which only the image source 1 is moved, the addition of the sixth lens unit 14, which has a positive focal length, means that the imaging light is constrained and focused before it enters the first prism unit 2. Therefore, both the required angle of entry and the amount of movement are smaller than in the method in which only the image source 1 is moved. Furthermore, the image source 1 and the sixth lens unit 14 move synchronously. With this movement method, during the movement process, the angle of the light after it passes through the sixth lens unit 14 remains constant for light emitted from the same position of the image source 1. In other words, the degree of divergence of the light emitted from the sixth lens unit 14 remains constant at different refractive indices, and the final field of view (FOV) is kept constant and does not shrink significantly.

[0241] In one embodiment, the second prism unit 3 has a polarizing plate on the side closer to the human eye 11, and the thickness of the polarizing plate is 60 nm to 250 nm.

[0242] Omitting the sixth lens unit 14 offers high design compatibility and is advantageous for mass production. Installing the sixth lens unit 14 can further improve image quality. The sixth lens unit 14 may also be in the form of a lens group. To reduce the rainbow fringes generated by the sixth lens unit 14, a polarizing absorption film can be attached to the surface of the second prism unit 3 closest to the eye. This suppresses the rainbow fringes. The principle is to reduce half of the stray light without affecting image formation by using linearly polarized light in the imaging direction (because stray light contains components parallel and perpendicular to the linearly polarized light used for imaging).

[0243] If possible, a polarizing plate may be attached to the surface of the second prism unit 3 closest to the eye. The thickness of the polarizing plate should be between 60 nm and 250 nm. If the thickness is too thin, it will be difficult to guarantee the desired effect even if the thin film is laminated. If the film thickness is too thick, light may be reflected inside the film, potentially causing ghost images. Therefore, a thickness of 60 nm to 250 nm guarantees the effect without causing other adverse effects and can eliminate stray light from the outside.

[0244] According to one or more embodiments of the present invention, each lens unit includes at least one lens. Preferably, the surface shape of each lens is any combination of a spherical, aspherical, free-form, Fresnel, and planar surface. In one embodiment, the first lens unit 4 is a curved lens.

[0245] In one embodiment, the aspherical surface satisfies the following equation.

number

[0246] In the above embodiment, the image source 1 is one of the following: an OLED display, an LCOS display, a MicroLED display, a DLP display, or an LBS display. The image source 1 includes, but is not limited to, the above devices. Preferably, it is an OLED display.

[0247] The operating principle of the above embodiment is as follows: Imaging light emitted from image source 1 is converted to 45° linear polarization by a linear polarization film, then passes through sixth lens unit 14, and is further guided onto first prism unit 2. A film system unit with optical path modulation function is attached to the surface of first prism unit 2 on the side closer to second prism unit 3. The 45° linear polarization is first totally reflected by first prism unit 2 and reaches the film system unit, where the 45° linear polarization is reflected and the -45° linear polarization is transmitted, and the light is reflected toward the outer surface of first lens unit 4. A semi-transparent semi-reflective film is provided on first lens unit 4, and the semi-transparent semi-reflective film reflects the light toward first prism unit 2. At this time, the angle of linear polarization becomes -45°, and it is transmitted sequentially through the film system unit and second prism unit 3, finally reaching the human eye 11 (eyeball) to form an image, as shown in Figure 15. Figure 16 is a schematic diagram showing the direction of optical path propagation and refractive power adjustment (synchronous movement of image source 1 and sixth lens unit 14).

[0248] The following will provide a detailed explanation using specific examples. In each table, OBJ represents the object plane, IMG represents the image plane, Stop represents the aperture, and Eye relief represents the eye relief (exit pupil distance). In the surface numbers, S2 and S3 both represent the surface on the second prism unit 3 that is close to the human eye 11. S4, S5, S12, and S13 all represent the surface on the first prism unit 2 that is close to the second prism unit 3. S6, S7, S11, S14, and S15 all represent the surface on the first prism unit 2 that is close to the first lens unit 4. S8 and S10 both represent the surface of the first lens unit 4 that is close to the first prism unit 2. S9 represents the surface on the first lens unit 4 that is far from the first prism unit 2. S16 and S17 both represent the surface on the first prism unit 2 that is close to the second lens unit 6. S18 and S19 both represent the light-emitting surface of the sixth lens unit 14. S20 indicates the light incident surface of the sixth lens unit 14. The light output side of the image source 1 is a flat glass plate (surface number S21), and the reference plane is a sphere.

[0249] According to one or more embodiments of the present invention, the apparatus includes an image source 1, a first prism unit 2, a second prism unit 3, a first lens unit 4, and a sixth lens unit 14. A polarization conversion unit is installed between the first prism unit 2 and the first lens unit 4. The image source 1 and the sixth lens unit 14 can also be moved synchronously for refractive power adjustment. The thicknesses of the linear polarizing film, film system unit, and polarization conversion unit are 120 nm, 200 nm, and 60 nm, respectively. The thickness of the semi-transparent, semi-reflective film is 100 nm. A polarizing plate is provided on the side of the second prism unit 3 closest to the human eye 11, and the thickness of the polarizing plate is 120 nm. In this embodiment, the film thickness is preferably a value close to the center so as to provide a good balance between image quality and reliability.

[0250] Table 7 Optical parameters at the refractive index of 0D in the examples

[0251] [Table 7]

[0252] Table 8 Optical parameters at the position of refractive power 6D in the examples

[0253] [Table 8]

[0254] According to the optical parameters in Table 7 and Table 8, the viewing angle (FOV) of the optical display in this example reaches 60°, and the thickness reaches 9.4 mm.

[0255] Figures 20 and 21 show the modulation transfer function (MTF) curves when adjusting the refractive power of 0D and 6D respectively. In the figure, the MTF exceeds 0.1 at 10 lp / mm. The device belongs to the visual optical system. By combining with the angular resolution of the human eye 11, this MTF index ensures that the human eye 11 receives a very clear and sharp image, and effectively guarantees the wearing experience.

[0256] According to one or more embodiments of the present invention, the apparatus comprises an image source 1, a first prism unit 2, a second prism unit 3, a first lens unit 4, and a sixth lens unit 14. A polarization conversion unit is installed between the first prism unit 2 and the first lens unit 4, and the image source 1 and the sixth lens unit 14 can be moved synchronously to adjust the refractive power. The thicknesses of the linear polarizing film, film system unit, and polarization conversion unit are 60 nm, 90 nm, and 30 nm, respectively. The thickness of the semi-transparent, semi-reflective film is 50 nm. A polarizing plate with a thickness of 60 nm is provided on the side of the second prism unit 3 closest to the human eye 11. In this embodiment, the film thicknesses are combined to be as thin as possible, making it suitable for optical systems that require ultra-thinness. This is a difficult challenge in the manufacturing process, and the raw material costs for thinning the linear polarizing film, film system unit, and polarization conversion unit are relatively high, but the imaging effect is similar to that of the above embodiment. The thinnest possible thickness of the deposited semi-transparent, semi-reflective film is 50 nm; if it is thinner than that, the coating becomes non-uniform and affects the imaging effect.

[0257] Table 9 Optical parameters at refractive index 0D in this embodiment

[0258] [Table 9]

[0259] Table 10 Optical parameters at refractive index 6D in this embodiment

[0260] [Table 10]

[0261] According to the optical parameters in Tables 9 and 10, the field of view (FOV) of the optical display device in this embodiment reaches 60°, and the thickness reaches 9.4 mm. Figures 22 and 23 show the modulation transfer function (MTF) curves when adjusted for refractive powers of 0D and 6D, respectively. In the figures, the MTF is greater than 0.1 at 10 lp / mm. The device belongs to the visual optical system, and when combined with the angular resolution of the human eye 11, this MTF index ensures that the human eye 11 receives a very clear and sharp image, effectively guaranteeing a comfortable wearing experience.

[0262] According to one or more embodiments of the present invention, the apparatus includes an image source 1, a first prism unit 2, a second prism unit 3, a first lens unit 4, and a sixth lens unit 14. A polarization conversion unit is installed between the first prism unit 2 and the first lens unit 4, and the image source 1 and the sixth lens unit 14 can also be moved synchronously for adjustment of refractive power. The thicknesses of the linear polarizing film, film system unit, and polarization conversion unit are 250 nm, 280 nm, and 100 nm, respectively. The thickness of the semi-transparent, semi-reflective film is 300 nm. A polarizing plate is provided on the side of the second prism unit 3 closest to the human eye 11, and the thickness of the polarizing plate is 250 nm. In this embodiment, the maximum values ​​are used for all film thicknesses, and there are a relatively large number of raw material types available for selection for the linear polarizing film, film system unit, and polarization conversion unit. Relatively thicker films are generally available earlier in the market, have more general performance descriptions, and have relatively poorer polarization conversion efficiency. The upper limit for the thickness of the semi-transparent, semi-reflective film is 300 nm, because exceeding this value carries the risk of delamination and affects the imaging effect.

[0263] Table 11 Optical parameters at refractive index 0D in this embodiment

[0264] [Table 11]

[0265] Table 12 Optical parameters at refractive index 6D in this embodiment

[0266] [Table 12]

[0267] According to the optical parameters in Tables 11 and 12, the field of view (FOV) of the wide-field, lightweight head-mounted display device of this embodiment reaches 60°, and the thickness reaches 9.4 mm. Figures 24 and 25 show the modulation transfer function (MTF) curves when adjusted for refractive powers of 0D and 6D, respectively. In the figures, the MTF is greater than 0.1 at 10 lp / mm. The device belongs to the visual optical system, and when combined with the angular resolution of the human eye 11, this MTF index ensures that the human eye 11 receives a very clear and sharp image, effectively guaranteeing a comfortable wearing experience.

[0268] According to one or more embodiments of the present invention, the apparatus comprises an image source 1, a first prism unit 2, a second prism unit 3, a first lens unit 4, and a sixth lens unit 14. A polarization conversion unit is installed between the first prism unit 2 and the first lens unit 4, and the image source 1 and the sixth lens unit 14 can also be moved synchronously for adjustment of refractive power. The thicknesses of the linear polarizing film, film system unit, and polarization conversion unit are 100 nm, 180 nm, and 80 nm, respectively. The thickness of the semi-transparent semi-reflective film is 100 nm. A polarizing plate with a thickness of 100 nm is provided on the side of the second prism unit 3 closest to the human eye 11. In this embodiment, the film thickness is preferably the above value to ensure compatibility with a narrow field of view (FOV) (i.e., less than 60°).

[0269] Table 13 Optical parameters at refractive index 0D in this embodiment

[0270] [Table 13]

[0271] Table 14 Optical parameters at refractive index 6D in this embodiment

[0272] [Table 14]

[0273] According to the optical parameters in Tables 13 and 14, the field of view (FOV) of the wide-field, lightweight head-mounted display device of this embodiment reaches 57°, and the thickness reaches 9.4 mm. Figures 26 and 27 show the modulation transfer function (MTF) curves when adjusted for refractive powers of 0D and 6D, respectively. In the figures, the MTF is greater than 0.1 at 10 lp / mm. The device belongs to the visual optical system, and when combined with the angular resolution of the human eye, this MTF index ensures that the human eye 11 receives a very clear and sharp image, effectively guaranteeing a comfortable wearing experience.

[0274] According to one or more embodiments of the present invention, the apparatus includes an image source 1, a first prism unit 2, a second prism unit 3, a first lens unit 4, and a sixth lens unit 14. A polarization conversion unit is installed between the first prism unit 2 and the first lens unit 4, and the image source 1 and the sixth lens unit 14 can also be moved synchronously along the optical axis for adjustment of refractive power. The thicknesses of the linear polarizing film, film system unit, and polarization conversion unit are 115 nm, 195 nm, and 60 nm, respectively. The thickness of the semi-transparent semi-reflective film is 100 nm. A polarizing plate is provided on the side of the second prism unit 3 closest to the human eye 11, and the thickness of the polarizing plate is 115 nm. In this embodiment, the film thickness is preferably the above value in order to ensure compatibility with a wide field of view (FOV) (i.e., 60° or more).

[0275] Table 15 Optical parameters at refractive index 0D in this embodiment

[0276] [Table 15]

[0277] Table 16 Optical parameters at refractive index 6D in this embodiment

[0278] [Table 16]

[0279] According to the optical parameters in Tables 15 and 16, the field of view (FOV) of the wide-field, lightweight head-mounted display device of this embodiment reaches 65°, and the thickness reaches 9.4 mm. Figures 25 and 26 show the modulation transfer function (MTF) curves when adjusted for refractive powers of 0D and 6D, respectively. In the figures, the MTF is greater than 0.1 at 10 lp / mm. The device belongs to the visual optical system, and when combined with the angular resolution of the human eye 11, this MTF index ensures that the human eye 11 receives a very clear and sharp image, effectively guaranteeing a comfortable wearing experience.

[0280] According to one or more embodiments of the present invention, as shown in Figures 30-32, the optical display device may include an image source 1, a first prism unit 2, a second prism unit 3, and a first lens unit 4.

[0281] Of these, the image source 1 is installed on the first surface 201 side of the first prism unit, the first lens unit 4 is installed in contact with the second surface 202 of the first prism unit, the first surface of the second prism unit 3 is installed in contact with the third surface 203 of the first prism unit, the first surface 201 and the third surface 203 of the first prism unit are closer to the wearer's eye than the second surface 202 of the first prism unit, and the first semi-transparent semi-reflective film is installed on the surface of the first lens unit 4 that is further away from the first prism unit 2.

[0282] The projected light emitted from image source 1 passes through the first surface 201 of the first prism unit and enters the first prism unit 2. It then undergoes total internal reflection by the second surface 202 of the first prism unit, reflection by the third surface 203 of the first prism unit, and transmission by the second surface 202 of the first prism unit before entering the first lens unit 4. After being reflected by the first semi-transparent semi-reflective film, it passes through the second surface 202 and third surface 203 of the first prism unit and the second prism unit 3 in order before being output and entering the human eye 11.

[0283] This embodiment further includes a seventh lens unit 15 in addition to the above. The seventh lens unit 15 is installed on the side of the first lens unit 4 that is away from the wearer's eye 11, and the focal length of the seventh lens unit 15 is the inverse of (opposite sign) the focal length of the first lens unit 4.

[0284] The second prism unit 3 includes at least one Fresnel lens.

[0285] The membrane unit is located between the first prism unit 2 and the second prism unit 3.

[0286] In this embodiment, the imaging light emitted from the image source 1 passes through the first surface 201 of the first prism unit and enters the first prism unit 2, where it is reflected once by the second surface 202 of the first prism unit, reflected a second time by the third surface 203 of the first prism unit, and then passes through the second surface 202 of the first prism unit before entering the first lens unit 4. It is reflected a third time by the first semi-transparent semi-reflective film, and then passes through the first prism unit 2 and the second prism unit 3 in order before entering the human eye 11.

[0287] As shown in Figure 30, the realization principle of the near-eye display device is as follows: Image light emitted from image source 1 passes through the first surface 201 of the first prism unit and enters the first prism unit 2. The first reflection occurs at the second surface 202 of the first prism unit, and the image light is reflected by the third surface 203 of the first prism unit. The film system unit is placed between the third surface 203 of the first prism unit and the second prism unit 3, thereby causing a second reflection at the third surface 203 of the first prism unit. Next, the image light passes through the second surface 202 of the first prism unit and enters the first lens unit 4. A first semi-transparent semi-reflective film is placed on the first lens unit 4, which reflects the image light to the first prism unit 2. Then, the light passes through the first prism unit 2 and the second prism unit 3 in sequence and enters the human eye 11.

[0288] Image source 1 can be any of OLED display, LCOS display, MicroLED display, DLP display, or LBS display. Preferably, it is an OLED display. The lightweight near-eye display device may further include an aperture, which is located between the second prism unit 3 and the human eye 11, or the aperture may be located at the position of the human eye 11.

[0289] The first prism unit 2 can be made of plastic or glass. The film system unit is installed between the third surface 203 of the first prism unit and the second prism unit 3. The film system unit can be attached to the first prism unit 2 or the second prism unit 3, or it can be coated onto the first prism unit 2 or the second prism unit 3. With this film system unit, the imaging light emitted from the image source 1 is reflected (or partially reflected) when it reaches the third surface 203 of the first prism unit, and the light reflected from the first lens unit 4 to the first prism unit 2 is transmitted.

[0290] The first lens unit 4 is composed of a series of lenses having aberration correction and optical path reflection functions. The material of each lens can be glass or plastic, and includes, but is not limited to, spherical lenses, aspherical lenses, free-form lenses, Fresnel lenses, and planar lenses. Preferably, it is a spherical lens. Furthermore, a first semi-transparent semi-reflective film is provided on the side away from the first prism unit 2. This first semi-transparent semi-reflective film can be realized by a coating method or a bonding method.

[0291] The seventh lens unit 15 can consist of a series of lenses having an aberration correction function. Its focal length is the inverse of (opposite sign) the focal length of the first lens unit 4, correcting the aberrations that occur when the human eye 11 looks at the outside through the first lens unit 4, so that the aberrations when the human eye 11 looks at the outside are sufficiently small. The seventh lens unit 15 can be made of plastic or glass, and the number of lenses is not limited. Examples of lenses include, but are not limited to, spherical lenses, aspherical lenses, free-form lenses, Fresnel lenses, and planar lenses. Preferably, it is a spherical lens.

[0292] The second prism unit 3 consists of a series of prisms having aberration correction and optical path difference compensation functions for the upper and lower fields of view. Of these, at least one prism is a Fresnel lens. The prisms can be made of plastic or glass, and their number is not limited. The surface shape includes, but is not limited to, spherical lenses, aspherical lenses, free-form lenses, Fresnel lenses, and planar lenses. Preferably, it is an aspherical lens. For example, the second prism unit 3 has one Fresnel lens, and its Fresnel surface is positioned to face the human eye 11.

[0293] According to one or more embodiments of the present invention, the film system unit includes at least one of a fourth semi-transmitting semi-reflective film, a reflective polarizing film, a quarter-wave plate, and an absorbing polarizing film.

[0294] For example, the film system unit can be a reflective polarizing film, or it can be a combination of a reflective polarizing film and a quarter-wave plate, in which case the quarter-wave plate may be placed between the reflective polarizing film and the first prism unit 2. The film system unit may also be a semi-transparent semi-reflective film, and can be specifically adjusted according to actual requirements.

[0295] In one embodiment, the ratio of transmittance to reflectance of each semi-transparent, semi-reflective film is 1:9 to 9:1. The semi-transparent, semi-reflective film has the function of partially reflecting and partially transmitting light, and its ratio of reflectance to transmittance can be determined according to the angle of incident light.

[0296] In one embodiment, the air gap between the first prism unit 2 and the first lens unit 4 is 0.01 to 1 mm.

[0297] In one embodiment, the second prism unit 3 includes a single Fresnel lens. In the Fresnel lens, the angle between the line segment connecting the roots of two adjacent teeth and the corresponding tooth width direction is 15° to 35°. The tooth width of the Fresnel lens is 0.1 mm or more, and the draft angle of the Fresnel lens teeth is 60° to 120°. Furthermore, the refractive indices of both the Fresnel lens and the first prism unit 2 are 1.45 to 1.75, and the Abbe numbers are both 18.0 to 60.0.

[0298] As shown in Figures 31 and 32, the second prism unit 3 includes a single Fresnel lens, which is positioned at an angle. One surface of the Fresnel lens is a smooth surface, and the other surface has concentric circles (i.e., Fresnel surfaces) formed from smaller to larger. The smooth surface and the third surface 203 of the first prism unit are parallel, and the Fresnel surfaces are positioned toward the human eye 11. In the Fresnel lens, the angle range between the line segment connecting the roots of two adjacent teeth and the corresponding tooth width direction is the same as the angle between the second surface 202 and the third surface of the first prism unit, and the range of material selection is also the same as that of the first prism unit, thereby better correcting the problem of principal ray deflection caused by the first prism. By setting the tooth width range to 0.1 mm or more, the risk of stray light and the problem of reduced transmittance caused by tooth width being too small can be reduced. By setting the draft angle to 60° to 120°, the angle of the principal ray in different fields of view can be better matched, reducing the risk of stray light and improving image quality.

[0299] In this embodiment, the angle α between the line segment connecting the roots of two adjacent teeth and the corresponding tooth width direction in the Fresnel lens is 27°. The refractive indices of both the Fresnel lens and the first prism are 1.72, and the Abbe numbers are both 29.5. The tooth width h is 0.25 mm, the direction of the tooth width h corresponds to the tooth width direction, and the tooth draft angle is 93°. The tooth width and draft angle of each tooth may differ or may be adjusted according to actual requirements.

[0300] The imaging light emitted from the image source 1 of the optical display device is reflected twice after entering the first prism unit 2, thereby achieving optical path folding. This ensures a sufficient optical path length for the imaging light while avoiding the problem of the overall volume of the near-eye display device increasing due to the volume of the first prism unit 2 becoming excessively large due to multiple reflections, thus contributing to the realization of a lightweight and thin design. Furthermore, by designing the second prism unit 3 to be a Fresnel lens in whole or in part, the overall weight of the near-eye display device can be further reduced without changing the optical path or performance. This allows the bottom of the near-eye display device to be made thinner. In addition, aberration correction is performed by the seventh lens unit 15, and the focal length of the seventh lens unit 15 is the inverse of the focal length of the first lens unit 4 (opposite sign). This corrects the aberrations that occur when the human eye 11 views the outside through the first lens unit 4, ensuring that the aberrations when the human eye 11 views the outside are sufficiently small. This device reduces overall weight by approximately 20% and significantly reduces the thickness of the base while ensuring that the imaging optical path is completely equivalent to that of existing technology. For example, the overall weight of the near-eye display device in this application is 6.5g and the thickness is approximately 3.8mm. The weight before weight reduction was approximately 8g and the thickness was approximately 8.7mm. The overall form is closer to that of eyeglasses, improving user comfort, experience, and aesthetics.

[0301] In one or more embodiments of the present invention, as shown in Figures 33 to 35, the optical display device may include an image source 1, a first prism unit 2, a second prism unit 3, and a first lens unit 4.

[0302] Of these, the image source 1 is installed on the first surface 201 side of the first prism unit, the first lens unit 4 is installed in contact with the second surface 202 of the first prism unit, and the first surface of the second prism unit 3 is installed in contact with the third surface 203 of the first prism unit. The first surface 201 and the third surface 203 of the first prism unit are closer to the wearer's eye than the second surface 202 of the first prism unit, and the first semi-transparent semi-reflective film is installed on the surface of the first lens unit 4 that is further away from the first prism unit 2.

[0303] The projected light emitted from image source 1 passes through the first surface 201 of the first prism unit and enters the first prism unit 2. It then sequentially undergoes total internal reflection by the second surface 202 of the first prism unit, reflection by the third surface 203 of the first prism unit, and transmission through the second surface 202 of the first prism unit before entering the first lens unit 4. After being reflected by the first semi-transparent semi-reflective film, it sequentially passes through the second surface 202, the third surface 203, and the second prism unit 3 of the first prism unit before entering the human eye 11.

[0304] In addition to the above, this embodiment further includes a film system unit, which is installed between the first prism unit 2 and the second prism unit 3.

[0305] The second prism unit 3 is a Fresnel lens and is positioned close to the third surface 203 of the first prism unit. The Fresnel surface of the Fresnel prism is positioned on the side closer to the wearer's eye 11 and satisfies the following conditions.

[0306] sin(β)*n>sin(max(aor)) or sin(β)*n <sin(min(aor))、 r / pitch<0.05, R / pitch < 0.05,

[0307] In the formula, β is the draft angle of each tooth, αor is the range of the angle between the line connecting the tip and root of each tooth to an arbitrary point on the aperture and the normal to the aperture, max(αor) is the maximum value of αor, min(αor) is the minimum value of αor, n is the refractive index of the Fresnel lens material, pitch is the tooth width of each tooth, r is the chamfer radius of the root of each tooth, and R is the chamfer radius of the tip of each tooth.

[0308] As shown in Figure 30, the realization principle of the near-eye display device is as follows. Imaging light emitted from the image source 1 passes through the first surface 201 of the first prism unit and enters the first prism unit 2. Since some of the light has an emission angle greater than the total reflection angle, the light is totally reflected at the surface of the first prism unit 2 on the side away from the human eye 11. That is, the first reflection occurs at the second surface 202 of the first prism unit, and the imaging light is reflected to the third surface 203 of the first prism unit. The film system unit is placed between the third surface 203 of the first prism unit and the second prism unit 3, causing a second reflection at the third surface 203 of the first prism unit, and then being transmitted through the second surface 202 of the first prism unit and entering the first lens unit 4. The first lens unit 4 is provided with a first semi-transparent semi-reflective film, which reflects the imaging light back to the first prism unit 2. Then, the light passes through the first prism unit 2 and the second prism unit 3 in order to reach the aperture, and enters the human eye 11 to form a virtual image. In this near-eye display device, the aperture is located at the position of the human eye 11, or is positioned between the second prism unit 3 and the human eye 11.

[0309] Image source 1 can be any of the following: OLED display, LCOS display, MicroLED display, DLP display, or LBS display. Preferably, it is an OLED display.

[0310] The first prism unit 2 can be made of plastic or glass. The film system unit is installed between the third surface 203 of the first prism unit and the second prism unit 3. The film system unit can be attached to the first prism unit or the second prism unit 3, or it can be coated onto the first prism unit or the second prism unit 3. The function of the film system unit is to reflect (or partially reflect) the imaging light emitted from the image source 1 when it first reaches the third surface 203 of the first prism unit, and to transmit the light reflected to the first prism unit 2 by the first lens unit 4.

[0311] The second prism unit 3 is a Fresnel lens, which can be made of plastic or glass, and the Fresnel surface is positioned facing the human eye 11. By adjusting the draft angle β of the Fresnel prism and minimizing the chamfer values ​​r and R as much as possible, the risk of stray light from the Fresnel prism is reduced, thereby achieving the objective of optimizing stray light in the near-eye display device.

[0312] As shown in Figure 35, the teeth of the Fresnel lens may be the same or different. As long as the above range is satisfied, the draft angle β, pitch, r, and R of each tooth may be the same or different. In the figure, n1 indicates the angle of incidence on the Fresnel surface of the Fresnel lens, and n2 indicates the angle of emission from the Fresnel surface of the Fresnel lens, which is determined by the refractive index n of the Fresnel lens material. The units of β and aor are degrees, and the units of pitch, r, and R are millimeters.

[0313] The first lens unit 4 is composed of a series of lenses having aberration correction and optical path reflection functions. The material of each lens can be glass or plastic, and may include, but is not limited to, spherical lenses, aspherical lenses, free-form lenses, Fresnel lenses, and planar lenses. Preferably, it is a spherical lens. Furthermore, a first semi-transparent semi-reflective film is installed on the side away from the first prism unit 2. This first semi-transparent semi-reflective film can be realized by a coating method or a bonding method, and the ratio of transmittance to reflectance can be 1:9 to 9:1, enabling the function of partially reflecting and partially transmitting light, and the ratio of reflectance to transmittance is determined according to the angle of incident light.

[0314] The optical display device includes an image source 1, a prism unit, and a lens unit, with the second prism unit 3 using a Fresnel prism. By adjusting the draft angle β, pitch, r, and R value of each tooth of the Fresnel prism, stray light generated by total internal reflection is directed out of the field of view, reducing ghosting (dragging images) and thus reducing the risk of stray light, thereby achieving the objective of optimizing stray light in the near-eye display device. Furthermore, by using a Fresnel prism, compared to the use of a conventional prism in the prior art, the imaging optical path is secured, the display effect is improved, and the overall weight is further reduced, thereby allowing the bottom of the device to be made thinner. In the prism total internal reflection structure, after the imaging light emitted from the display chip is incident on the imaging prism unit, the optical path is folded by multiple reflections, ensuring a sufficient optical path length for the imaging light while avoiding an excessive volume of the imaging prism unit. This avoids the problem of increasing the overall volume of the near-eye display device, which is advantageous for further weight reduction and thinning of the overall device, improving user comfort, user experience, and aesthetics.

[0315] In one embodiment, the film system unit includes at least one of a fifth semi-transmissive semi-reflective film, a reflective polarizing film, a quarter-wave plate, and an absorbing polarizing film.

[0316] Alternatively, the film system unit may be a semi-transparent, semi-reflective film, and can be adjusted according to actual requirements. The ratio of transmittance to reflectance of the semi-transparent, semi-reflective film can be 1:9 to 9:1, and it has the function of partially reflecting and partially transmitting light. The ratio of reflection to transmission is determined according to the angle of the incident light.

[0317] In one embodiment, the air gap between the first prism unit 2 and the first lens unit 4 is 0.01 mm to 1.0 mm.

[0318] The goal is to reduce the overall thickness of the device while ensuring the necessary air layer for total internal reflection. Specifically, if the thickness is less than 0.01 mm, it cannot be guaranteed that the air layer will still exist even considering a certain tolerance, and if it exceeds 1.0 mm, the overall thickness of the device increases, which is disadvantageous for achieving a lightweight and thin design.

[0319] In one embodiment, the first lens unit 4 is a curved lens, and the radius of curvature R11 of the first surface of the first lens unit 4 satisfies R11≧150mm or R11≦-150mm, and the radius of curvature R12 of the second surface of the first lens unit 4 satisfies 40mm≦R12≦75mm. The first surface 201 of the first prism unit is a curved surface, and its radius of curvature R13 satisfies R13≧22mm or R13≦-100mm. The first surface of the first lens unit 4 is the surface closer to the first prism unit 2, and the second surface of the first lens unit 4 is the surface further away from the first prism unit 2.

[0320] Preferably, the refractive index of the first lens unit 4 is 1.50 to 1.90, and the Abbe number is 38.0 to 85.0. What I would like to explain is that in this embodiment, any even-order aspherical surface among the above lenses satisfies the following aspherical formula. JPEG2026529165000023.jpg34140

[0321] In the formula, z is the vector height, Y is the lens center height, k is the conicity coefficient, C is the curvature, is the 2i-th order aspheric coefficient, and N is a positive integer.

[0322] Preferably, the refractive indices of both the first prism unit 2 and the second prism unit 3 are 1.45 to 1.75, and the Abbe numbers are both 18.0 to 60.0. A smaller Abbe number is preferable, as it reduces chromatic aberration.

[0323] In one embodiment, an eighth lens unit is further included. The eighth lens unit is installed in close proximity to the first semi-transparent semi-reflective film, and the focal length of the eighth lens unit and the focal length of the lens unit are inversely proportional (opposite signs).

[0324] The eighth lens unit consists of a series of lenses with aberration correction functions. Its focal length is the inverse of (opposite sign) the focal length of the first lens unit 4, thereby correcting the aberrations that occur when the human eye 11 looks at the outside through the first lens unit 4, so that the aberrations seen by the human eye 11 are sufficiently small. The lenses of the eighth lens unit can be made of plastic or glass, and there is no limit to the number of lenses. Examples of lenses include, but are not limited to, spherical lenses, aspherical lenses, free-form surface lenses, Fresnel lenses, and planar lenses. Preferably, they are spherical lenses. What we would like to explain is that if the lenses in the eighth lens unit and the first lens unit 4 are aspherical lenses, their surfaces satisfy the formula for even-order aspherical lenses.

[0325] In one embodiment, the focal length of the first lens unit 4 is 10mm to 25mm.

[0326] The device ensures a reasonable optical path length to prevent the image source 1 from sinking and interfering with the surface of the first prism unit 2. It also avoids the device becoming too large and impractical due to an excessively long optical path length. Preferably, the focal length of the first lens unit 4 is 11 mm to 23 mm.

[0327] In one embodiment, the refractive power is adjusted by moving the image source 1 relative to the first prism unit 2.

[0328] By changing the distance between the image source 1 and the first surface 201 of the first prism unit, the imaging position of the image light can be changed, thereby enabling adjustment of the refractive power, and thus allowing it to be adapted to wearers with different myopia prescriptions.

[0329] To facilitate understanding, the following will provide a detailed explanation based on specific examples.

[0330] The parameters of each optical element in this embodiment are shown in Table 1 below.

[0331] [Table 17]

[0332] In Table 17, surface number S0 represents the object surface, surface number S1 represents the aperture, surface number S2 represents the Fresnel surface of the Fresnel prism, surface number S3 represents the plane on the Fresnel prism near the first prism unit 2, surface numbers S4 and S10 represent the third surface 203 of the first prism unit, surface numbers S5, S9 and S11 represent the second surface 202 of the first prism unit, surface numbers S6 and S8 represent the surface of the first lens unit 4 near the first prism unit 2, and surface number S7 represents the surface of the first lens unit 4 away from the first prism unit 2. The radius of curvature "-" indicates the opposite direction to the bending direction of surface S6 or surface S8. Surface number S12 represents the first surface 201 of the first prism unit, surface number S13 represents the surface on the image source 1 near the first prism unit 2, and surface number S14 represents the surface on the image source 1 away from the first prism unit 2. Furthermore, the tooth width pitch of the second prism unit 3 is 0.25 mm.

[0333] As shown in Figures 36-38, when the second prism unit 3 uses an ideal Fresnel prism (β=0°, R=0μm, and r=0μm), a very pronounced double-image phenomenon occurs. When the threshold energy is reduced, ghost images (double images) similar in shape to pixels are observed on the screen. Specifically, this is shown as a bright spot (ineffective optical path imaging, interfering with the normal screen) below in Figure 35. Reducing the threshold energy means lowering the brightness by an order of magnitude. As shown in Figures 39 and 40, Figure 39 is a stray light simulation optical path diagram in a near-eye display device when β=0°, R=0μm, and r=0μm. As can be seen from Figure 40, the source of the ghost image is due to total internal reflection of the light ray at the yaw point of the Fresnel prism. Furthermore, the energy of the ghost image is approximately 1 / 40th of that of a pixel.

[0334] As shown in Figures 41 to 45, when the second prism unit 3 uses a normal Fresnel prism, the chamfering (β=0°, R=25μm, r=25μm) that occurs during the actual manufacturing of a normal Fresnel prism causes a dragged image phenomenon, i.e., a ghosting phenomenon. Figure 42 is a simulation irradiance distribution diagram of the overall positive direction for a near-eye display device at β=0°, R=25μm, r=25μm. However, since the imaging irradiance is much greater than the irradiance of the ghost image caused by stray light, the threshold energy is reduced in Figure 43 to make the irradiance of the ghost image clearer. Figure 44 shows a simulation optical path diagram of stray light for a near-eye display device at β=0°, R=25μm, r=25μm. As can be seen from Figure 45, the dragged image is caused by the refraction of light at the chamfered part of the Fresnel prism, and the energy of the dragged image (ghost image) is about 1 / 125 of that of the pixel.

[0335] As shown in Figures 46-50, the draft angles β, r, and R of the second prism are adjusted. In this embodiment, β=12°, R=5μm, and r=5μm. Figure 46 shows the simulated optical path diagram for the near-eye display device with β=12°, R=5μm, and r=5μm. Figure 47 shows the overall positive directional simulated illuminance for β=12°, R=5μm, and r=5μm. However, since the imaging illuminance is much greater than the illuminance of the ghost image caused by stray light, the threshold energy is reduced in Figure 48 to make the illuminance of the ghost image clearer. Figure 49 shows the stray light simulated optical path diagram of the near-eye display device with β=12°, R=5um, and r=5um. As can be seen from Figure 50, the double image disappears, the energy of the trailing image is about 1 / 540 of the pixel energy, and stray light is significantly improved.

[0336] It is important to note that, in this specification, terms expressing relationships such as “first,” “second,” etc., are used solely to distinguish one entity or operation from another, and do not necessarily imply or require any actual relationship or order between these entities or operations. Furthermore, “includes,” “incorporates,” or other variations thereof, are intended to indicate non-exclusive inclusion, and a process, method, article, or apparatus containing a set of elements includes its own elements. Also, without further limitation, an element defined by the phrase “includes one…” does not preclude the existence of other identical elements in a process, method, article, or apparatus containing that element. In addition, detailed descriptions of the above technical configurations provided in the embodiments of this application that are consistent with the implementation principles of corresponding technical configurations in the prior art are omitted to avoid redundant explanations.

[0337] This specification uses specific examples to illustrate the principles and methods of carrying out the present invention. The above description of examples helps to understand the methods and core concepts of the present invention. Those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications are also covered by the scope of the claims of the present invention.

Claims

1. An optical display device comprising an image source (1), a first prism unit (2), a second prism unit (3), and a first lens unit (4), of which, The image source (1) is installed on the first surface (201) side of the first prism unit, the first lens unit (4) is installed in contact with the second surface (202) of the first prism unit, the first surface (301) of the second prism unit is installed in contact with the third surface (203) of the first prism unit, the first surface (201) and the third surface of the first prism unit are located closer to the wearer's eye than the second surface (202) of the first prism unit, and the first semi-transparent semi-reflective film is installed on the surface of the first lens unit (4) that is away from the first prism unit (2). The optical display device is characterized in that the projected light emitted from the image source (1) passes through the first surface (201) of the first prism unit, enters the first prism unit (2), undergoes total internal reflection by the second surface (202) of the first prism unit, is reflected by the third surface (203) of the first prism unit, is transmitted by the second surface (202) of the first prism unit, then enters the first lens unit (4), is reflected by the first semi-transparent semi-reflective film, is transmitted by the second surface (202) and third surface of the first prism unit and the second prism unit (3), and then enters the human eye (11).

2. The optical display device according to claim 1, characterized in that the angle α between the second surface (202) and the third surface of the first prism unit satisfies 15° < α < 35°, the angle b between the first surface and the second surface of the second prism unit (3) satisfies 15° < b < 25° and a - b ≤ 10°, and the second surface (302) of the second prism unit is the surface that emits projected light.

3. A polarizing film is provided on the third surface (203) of the first prism unit, and a first quarter-wave plate (5) is positioned between the first lens unit (4) and the polarizing film. The optical display device according to claim 1, further characterized in that a second semi-transparent semi-reflective film is arranged on the third surface (203) of the first prism unit.

4. The optical display device according to claim 1, characterized in that a fourth surface (204) of the first prism unit is further present between the first surface (201) of the first prism unit and the third surface (203) of the first prism unit, and the fourth surface (204) of the first prism unit and the second surface (202) of the first prism unit are parallel, or the fourth surface (204) of the first prism unit and the second surface (302) of the second prism unit are parallel.

5. The first prism unit (2) and the second prism unit (3) are both prisms with a refractive index of 1.45 to 1.75 and an Abbe number of 18.0 to 60.

0. The first lens unit (4) satisfies the following conditions: focal length f1 is 10 mm ≤ f1 ≤ 25 mm, refractive index is 1.45 to 1.90, Abbe number is 35.0 to 85.0, radius of curvature R11 of the first surface is R11 ≥ 100 mm or R11 ≤ -100 mm, and radius of curvature R12 of the second surface is 40 mm ≤ R12 ≤ 80 mm. Of these, the first surface of the first lens unit (4) is the surface closer to the first prism unit (2), and the second surface of the first lens unit (4) is the surface further away from the first prism unit (2). The optical display device according to claim 1, characterized in that the gap between the first surface of the first lens unit (4) and the second surface (202) of the first prism unit is 0.01 mm to 1.0 mm.

6. The optical display device according to any one of claims 1, characterized in that the image source (1) is movable relative to the first prism unit (2) and the distance of movement is less than 2.5 mm.

7. The optical display device according to claim 6, characterized in that the angle between the direction in which the image source (1) moves relative to the first prism unit (2) and the optical axis direction of the image source (1) is 0° to 15°.

8. The optical display device according to any one of claims 1 to 7, characterized in that a second lens unit (6) is further installed between the image source (1) and the first surface (201) of the first prism unit.

9. The optical display device according to claim 8, characterized in that the refractive power is adjusted by synchronously moving the second lens unit (6) and the image source (1) relative to the first prism unit (2).

10. The second lens unit (6) has a focal length f2 satisfying f2 ≥ 50 mm or f2 ≤ -50 mm, a refractive index of 1.45 to 1.90, an Abbe number of 35.0 to 85.0, and the radius of curvature R21 of the first surface and the radius of curvature R22 of the second surface satisfying |R21 - R22| > 50 mm, wherein the first surface (601) of the second lens unit is the surface on the side away from the first prism unit (2), and the second surface (602) of the second lens unit is the surface on the side closer to the first prism unit (2). The optical display device according to claim 8, characterized in that the gap between the first surface (601) of the second lens unit and the first surface (201) of the first prism unit is 0.05 mm to 3.00 mm.

11. An optical display device according to any one of claims 1 to 5, wherein a third lens unit (7) is further provided on the second surface (302) side of the second prism unit, and the second surface (302) of the second prism unit is the surface through which projected light is transmitted from the second prism unit (3) and emitted.

12. The optical display device according to claim 11, characterized in that the third lens unit (7) has a focal length f3 satisfying f3 ≥ 50 mm or f3 ≤ -50 mm, a refractive index of 1.45 to 1.90, an Abbe number of 35.0 to 85.0, a radius of curvature R31 of the first surface satisfying R31 ≥ 100 mm or R31 ≤ -100 mm, and a radius of curvature R32 of the second surface satisfying R32 ≥ 100 mm or R32 ≤ -100 mm, wherein the first surface (701) of the third lens unit is the surface on the side closer to the body of the second prism unit (3), and the second surface (702) of the third lens unit is the surface on the side further away from the body of the second prism unit (3).

13. The optical display device according to claim 11, characterized in that the third lens unit (7) can adjust the refractive power by moving along the optical axis relative to the second prism unit (3).

14. The film system unit is further comprising the aforementioned film system unit, which is used to reflect all or part of the light emitted from the image source (1) to the first lens unit (4), and to transmit the light reflected by the first lens unit (4) to the first prism unit (2). The optical display device according to claim 1, characterized in that the film system unit is installed between the third surface (203) of the first prism unit and the first surface (301) of the second prism unit.

15. The optical display device according to claim 14, characterized in that the first surface (201) of the first prism unit is spherical or aspherical, and the surface of the first lens unit (4) is any combination of a spherical surface, an aspherical surface, a free-form surface, a Fresnel surface, and a plane.

16. The optical display device according to claim 15, characterized in that the image source (1) can be moved relative to the first surface (201) of the first prism unit to adjust the refractive power, and the focal length of the first surface (201) of the first prism unit is 25 mm to 200 mm.

17. The optical display device according to claim 14, further comprising a fourth lens unit (8), wherein the fourth lens unit (8) is installed in close proximity to the first semi-transparent semi-reflective film, and the focal length of the fourth lens unit (8) is inversely proportional to the focal length of the first lens unit (4).

18. The optical display device according to claim 17, characterized in that the focal length of the first lens unit (4) is 10 mm to 25 mm.

19. The optical display device according to claim 14, characterized in that the film system unit includes at least one of a third semitransmitting semi-reflective film, a reflective polarizing film, a quarter-wave plate, and an absorbing polarizing film.

20. The optical display device according to claim 19, characterized in that the ratio of transmittance to reflectance of each of the semi-transparent, semi-reflective films is 1:9 to 9:

1.

21. The optical display device according to claim 14, characterized in that the distance between the image source (1) and the first surface (201) of the first prism unit is 0.25 mm to 3.0 mm.

22. The optical display device further satisfies the following conditions: R1 ≤ -100 mm or R1 ≥ 100 mm, -40mm≦R2≦-100mm, R3 ≤ -200 mm or R3 ≥ 18 mm, The optical display device according to claim 15, characterized in that R1 represents the radius of curvature of the surface on the first lens unit (4) that is close to the fourth lens unit (8), R2 represents the radius of curvature of the side of the first lens unit (4) that is farther from the fourth lens unit (8), and R3 represents the radius of curvature of the first surface (201) of the first prism unit.

23. The aforementioned aspherical surface is given by the following equation: [Math 1] (In the formula, z is the vector height, Y is the lens center height, k is the conicity coefficient, C is the curvature, is the 2i-th order aspheric coefficient, and N is a positive integer.) The optical display device according to claim 22, characterized in that it satisfies the requirements.

24. The optical display device further satisfies the following conditions: The optical display device according to claim 23, wherein R represents the radius of curvature in mm, Len1_S1 represents the surface on the first lens unit (4) that is close to the fourth lens unit (8), Len1_S2 represents the surface on the first lens unit (4) that is far from the fourth lens unit (8), and P2_S3 represents the first surface (201) of the first prism unit.

25. Furthermore, it includes a first polarizing unit (9), which is located between the first prism unit (2) and the second prism unit (3), and is used to reflect imaging light in the first polarized light transmission direction to the first lens unit (4) and to transmit imaging light in the second polarized light transmission direction, the first polarized light transmission direction exhibits a 90° angle with respect to the second polarized light transmission direction, and the first polarized light transmission direction is the same as the polarized light transmission direction of the image source (1), the first semi-transparent semi-reflective film reflects imaging light in the first polarized light transmission direction, then passes through the first prism unit (2) and the second prism unit (3) in sequence and is incident on the human eye (11), and transmits real-world light, then passes through the first prism unit (2) and the second prism unit (3) in sequence and is incident on the human eye (11), The optical display device according to claim 1, wherein a second polarizing unit (10) is further attached to the second surface (302) of the second prism unit, and the second polarizing unit (10) is used to transmit light parallel to the third polarizing transmission direction and reflect light perpendicular to the third polarizing transmission direction, and the third polarizing transmission direction is the same as the second polarizing transmission direction.

26. The optical display device according to claim 25, characterized in that the first polarizing unit (9) includes a first linear polarizing plate (91), a polarizing reflector (92), and a second quarter-wave plate (93) which are sequentially installed along the direction from the second prism unit (3) toward the first prism unit (2).

27. The optical display device according to claim 25, characterized in that the image source (1) is further provided with a third polarization unit (12), and the third polarization unit (12) is used to convert image light into 45° linearly polarized light.

28. The optical display device according to claim 27, characterized in that the second polarizing unit (10) includes a second linear polarizer and the third polarizing unit (12) includes a third linear polarizer.

29. The optical display device according to claim 27, characterized in that the 45° linearly polarized light is reflected once on the second surface (202) of the first prism unit to form a first ray, the first ray is reflected a second time on the first polarizing unit (9) to form a second ray, the second ray is reflected a third time on the first semi-transparent semi-reflective film to form a third ray, the third ray is converted into a fourth ray by the first polarizing unit (9), passes through the second polarizing unit (10) and is incident on the human eye (11), the first ray is 45° linearly polarized, the second ray is left-handed circularly polarized, the third ray is right-handed circularly polarized, the fourth ray is -45° linearly polarized, and the second polarizing unit (10) transmits -45° linearly polarized light and reflects 45° linearly polarized light.

30. The optical display device according to claim 25, further comprising a fifth lens unit (13), wherein the fifth lens unit (13) is installed between the image source (1) and the first prism unit (2), and the fifth lens unit (13) includes at least one lens.

31. The optical display device according to claim 30, characterized in that the fifth lens unit (13) and the image source (1) adjust the refractive power by moving synchronously with respect to the first prism unit (2).

32. It is further equipped with a polarization conversion unit, The image source (1) is provided with a linear polarizing film on its light-emitting side. Furthermore, it includes a film system unit, the film system unit includes a polarizing reflection unit, and is attached to the third surface (203) of the first prism. The polarization conversion unit is installed between the first prism unit (2) and the first lens unit (4), or between the polarization reflection unit and the first prism unit (2). The thickness of the linear polarizing film is 60 nm to 250 nm, the thickness of the film system unit is 90 nm to 280 nm, the thickness of the polarization conversion unit is 30 nm to 100 nm, and the thickness of the semitransmissive semi-reflective film is 50 nm to 300 nm. The optical display device according to claim 1, characterized in that the imaging light emitted from the image source (1) is converted into linearly polarized light by the linearly polarizing film, the linearly polarized light is incident on the first prism unit (2), undergoes total internal reflection and reaches the film system unit, is further reflected by the film system unit and reaches the first lens unit (4), is then reflected by the first semi-transparent semi-reflective film on the first lens unit (4) and reaches the first prism unit (2), and is further transmitted sequentially through the film system unit and the second prism unit (3) before reaching the human eye (6) and forming an image.

33. The optical display device according to claim 32, characterized in that the polarization conversion unit is a quarter-wave plate (5), and the angle between the reflection axis of the film system unit and the slow axis of the polarization conversion unit is 45° ± 1°.

34. The optical display device according to claim 33, characterized in that the polarizing reflective unit is a polarizing reflective film.

35. The optical display device according to claim 32, wherein the film system unit further comprises a polarization absorption unit, the polarization absorption unit is a polarization absorption film, is located between the polarization reflection unit and the second prism unit (3), and the absorption axis of the polarization absorption unit is parallel to the reflection axis of the polarization reflection unit.

36. The optical display device according to claim 32, characterized in that the image source (1) is further movable relative to the first prism unit (2), and the movement distance is less than 5 mm.

37. The optical display device according to claim 36, characterized in that the angle between the direction in which the image source (1) moves relative to the first prism unit (2) and the optical axis direction of the image source (1) is between 0° and 15°.

38. The optical display device according to claim 32, further comprising a sixth lens unit (14), wherein the sixth lens unit (14) is located on the light emission side of the image source (1), and the linearly polarized light is incident on the first prism unit (2) via the sixth lens unit (14).

39. The optical display device according to claim 38, characterized in that the focal length of the sixth lens unit (14) is 5 mm to 50 mm.

40. The optical display device according to claim 38, characterized in that the image source (1) and the sixth lens unit (14) can be further moved synchronously with respect to the first prism unit (2), and the movement distance is less than 4 mm.

41. The optical display device according to claim 40, characterized in that the angle between the direction in which the image source (1) and the sixth lens unit (14) move synchronously with respect to the first prism unit (2) and the optical axis direction of the image source (1) is 0° to 10°.

42. The optical display device according to claim 38, characterized in that a polarizing plate is further provided on the side of the second prism unit closest to the human eye (11), and the thickness of the polarizing plate is 60 nm to 250 nm.

43. The optical display device according to claim 38, characterized in that each of the aforementioned lens units includes at least one lens.

44. The optical display device according to claim 43, characterized in that the surface shape of each of the lenses is any combination of a spherical surface, an aspherical surface, a free-form surface, a Fresnel surface, and a plane.

45. The optical display device according to claim 43, characterized in that the first lens unit is a curved lens.

46. The aforementioned aspherical surface is given by the following equation: [Math 1] (In the formula, z is the vector height, Y is the lens center height, k is the conicity coefficient, C is the curvature, a) ｉ (where is the i-th order aspherical coefficient and N is a positive integer) The optical display device according to claim 44, characterized in that it satisfies the requirements.

47. Furthermore, it includes a seventh lens unit (15), the seventh lens unit (15) being positioned on the side of the first lens unit (4) away from the wearer's eye (11), and the focal length of the seventh lens unit (15) being inversely proportional to the focal length of the first lens unit (4). The second prism unit (3) includes at least one Fresnel lens, The optical display device according to claim 1, characterized in that a film system unit is located between a first prism unit (2) and a second prism unit (3).

48. The optical display device according to claim 47, characterized in that the film system unit includes at least one of a fourth semitransmitting semi-reflective film, a reflective polarizing film, a quarter-wave plate (5), and an absorbing polarizing film.

49. The optical display device according to claim 48, characterized in that the ratio of transmittance to reflectance of each of the semi-transparent, semi-reflective films is 1:9 to 9:

1.

50. The optical display device according to claim 47, characterized in that the air gap between the first prism unit (2) and the first lens unit (4) is 0.01 mm to 1 mm.

51. The optical display device according to claim 47, characterized in that the second prism unit (3) includes a Fresnel lens, the angle between the line connecting the roots of two adjacent teeth of the Fresnel lens and the corresponding tooth width direction is 15° to 35°, the tooth width of the Fresnel lens is 0.1 mm or more, the draft angle of the teeth of the Fresnel lens is 60° to 120°, and the refractive indices of the Fresnel lens and the first prism unit (2) are both 1.45 to 1.75, and the Abbe numbers are both 18.0 to 60.

0.

52. Furthermore, it includes a film system unit, which is installed between the first prism unit (2) and the second prism unit (3). The second prism unit (3) is a Fresnel lens and is installed in close proximity to the third surface (203) of the first prism unit, and the Fresnel surface of the Fresnel prism is installed on the side closer to the wearer's eye (11), and satisfies the following conditions: sin(β)*n>sin(max(aor)) or sin(β)*n<sin(min(aor)) )), r / pitch<0.05, R / pitch<0.05, The optical display device according to claim 1, characterized in that, in the formula, β is the draft angle of each tooth, αor is the range of the angle between the line connecting the tip and root of each tooth to an arbitrary point on the aperture and the normal to the aperture, max(αor) is the maximum value of αor, min(αor) is the minimum value of αor, n is the refractive index of the Fresnel lens material, pitch is the tooth width of each tooth, r is the chamfer radius of the root of each tooth, and R is the chamfer radius of the tip of each tooth.

53. The optical display device according to claim 52, characterized in that the pitch value range of the Fresnel surface of the second prism unit (3) is 0.15 mm to 0.6 mm, and the range of values ​​for r and R is both 0.05 mm to 0.02 mm.

54. The optical display device according to claim 52, characterized in that the film system unit includes at least one of a fifth semi-transmissive semi-reflective film, a reflective polarizing film, a quarter-wave plate (5), and an absorbing polarizing film.

55. The optical display device according to claim 52, characterized in that the air gap between the first prism unit (2) and the first lens unit (4) is 0.01 mm to 1.0 mm.

56. The optical display device according to claim 52, characterized in that the first lens unit (4) is a curved lens, and the radius of curvature R11 of the first surface of the first lens unit (4) satisfies R11 ≥ 150 mm or R11 ≤ -150 mm, the radius of curvature R12 of the second surface of the first lens unit (4) satisfies 40 mm ≤ R12 ≤ 75 mm, the first surface (201) of the first prism unit is a curved surface, and the radius of curvature R13 satisfies R13 ≥ 22 mm or R13 ≤ -100 mm, the first surface of the first lens unit (4) is the surface on the side closer to the first prism unit (2), and the second surface of the first lens unit (4) is the surface on the side further away from the first prism unit (2).

57. The optical display device according to claim 52, further comprising an eighth lens unit, wherein the eighth lens unit is installed near the first semi-transparent semi-reflective film, and the focal length of the eighth lens unit is inversely proportional to the focal length of the lens unit.

58. The lightweight, thin, and stray-light-eliminating near-eye display device according to claim 57, characterized in that the focal length of the first lens unit (4) is 10 mm to 25 mm.

59. The lightweight, thin, and stray-light-eliminating near-eye display device according to claims 25 and 52, characterized in that the image source (1) adjusts its refractive power by moving relative to the first prism unit (2).

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