Lens assembly, optical system and display device

Abstract

The embodiment of the invention relates to the technical field of display, and provides a lens assembly, an optical system and display equipment. The lens assembly comprises a plurality of lenses which are sequentially arranged from an object side to an image side; the light splitting element, the first quarter-wave plate and the reflection polarization element are sequentially arranged from the object side to the image side; and a lens barrel. At least one of the first quarter-wave plate and the reflective polarization element is fixed on the lens barrel independent of the plurality of lenses; or the object side surfaces and the image side surfaces of the plurality of lenses comprise at least one binding surface, and at least one of the first quarter-wave plate and the reflection polarization element is bound on the binding surface. And the binding surface is a quadric surface of which the curvature in at least one direction is zero.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular, to a lens assembly, an optical system and a display device. Background Art

[0002] In existing folded optical path type virtual reality (VR) display devices, in order to optimize image quality, the surface of the lens used to bond the optical film is usually a circular arc surface (such as a spherical or aspherical surface), and the curved bonding process is difficult. Moreover, as the radius of curvature of the lens decreases, the performance of optical film layers such as quarter-wave plates and reflective polarizing elements decreases, which not only causes problems such as color deviation and uniformity, but also causes problems such as orange peel wrinkles, bubbles, and inability to bond the optical film. Summary of the invention

[0003] In a first aspect, the present application provides a lens assembly, the lens assembly comprising:

[0004] A plurality of lenses arranged in sequence from the object side to the image side, each lens comprising an object side surface and an image side surface arranged opposite to each other, the object side surface of each lens faces the object side, and the image side surface of each lens faces the image side;

[0005] A beam splitter, a first quarter wave plate and a reflective polarizing element are arranged in sequence from the object side to the image side; and

[0006] A lens barrel, a plurality of lenses, a beam splitter, a first quarter wave plate and a reflective polarization element are all located in the lens barrel and are all located on an optical path between the object side and the image side;

[0007] At least one of the first quarter wave plate and the reflective polarizing element is fixed on the lens barrel independently of the multiple lenses; or, the object side surface and the image side surface of the multiple lenses include at least one bonding surface, and at least one of the first quarter wave plate and the reflective polarizing element is bonded to the bonding surface, and the bonding surface is a quadratic surface with zero curvature in at least one direction.

[0008] In the lens assembly of the first aspect of the present application, when the first quarter wave plate and / or the reflective polarizing element are fixed on the lens barrel, the problems of color deviation, uniformity reduction, orange peel wrinkles, bubbles, inability to bond, etc. of the first quarter wave plate and / or the reflective polarizing element after bonding caused by the existing bending bonding process can be directly avoided; and when the first quarter wave plate and / or the reflective polarizing element are bonded to the bonding surface, the bonding surface is a quadratic surface with zero curvature in at least one direction, which is conducive to reducing the difficulty of bonding the first quarter wave plate and / or the reflective polarizing element to the lens through the bending bonding process, and is conducive to solving the problems of color deviation, uniformity reduction, orange peel wrinkles, bubbles, inability to bond, etc. of the first quarter wave plate and / or the reflective polarizing element after bonding using the bending bonding process.

[0009] In some embodiments, the surface equation of a quadratic surface with zero curvature in at least one direction is:

[0010]

[0011] In the surface equation of a quadratic surface with zero curvature in at least one direction, Rx is the radius of curvature of the bonding surface in the first direction, Ry is the radius of curvature of the bonding surface in the second direction, Z1 is the sagittal height of the bonding surface in the third direction, the first direction, the second direction and the third direction are perpendicular to each other, kx and ky are the cone coefficients, and the value of one of Rx and Ry is infinite. Since the value of one of Rx and Ry in the surface equation of the bonding surface is infinite, the curvature of the bonding surface in one of the first direction or the second direction approaches zero, and the curvature changes in the other of the first direction and the second direction. Therefore, it can solve the problems caused by the curved bonding process, and compared with the bonding surface being a plane, it can also bear a certain optical focal length for the lens assembly, which is conducive to improving the processing and manufacturing accuracy of the lens.

[0012] In some embodiments, the object side and image side of the plurality of lenses further include at least one free-form surface, at least one of a free-form surface, a spherical surface, a rotationally symmetric aspherical surface and a Fresnel surface. The free-form surface includes at least one of an extended polynomial surface, a Zernike polynomial surface and a Q-type polynomial surface. Since the free-form surface can provide more optimization variables, it has the following advantages: first, it is conducive to increasing the field of view angle of the optical system; second, it is conducive to reducing the aperture of the lens, thereby reducing the weight of the optical system; third, it is conducive to reducing distortion and increasing screen utilization; fourth, it reduces the thickness ratio of the lens, improves the processing technology of the lens, and reduces the weight of the optical system. Specifically, the surface description of the extended polynomial surface is simple, the design freedom is high, and it is consistent with the form of CNC machining of optical surfaces. The Zernike polynomial surface has a direct correspondence with the aberration, which is conducive to correcting the aberration of the optical system in a targeted manner based on the vector aberration theory. The surface coefficients of the Q-type polynomial surface can be directly used to characterize the gradient of the surface's elevation deviation relative to the best-fit sphere. It can be used for tolerance analysis of free-form surfaces, allowing the evaluation of optical design and processing inspection difficulty to be performed simultaneously, thus avoiding the tedious process of processing evaluation after design. Spherical surfaces are conducive to lens processing and have low costs. Compared with spherical surfaces, rotationally symmetric aspherical surfaces are conducive to correcting spherical aberrations of imaging and improving imaging quality. Compared with spherical surfaces and rotationally symmetric aspherical surfaces, Fresnel surfaces have short focal lengths, small volumes, light weights, and compact structures.

[0013] In some embodiments, the object-side surfaces and the image-side surfaces of the plurality of lenses include rotationally symmetric aspherical surfaces, and the surface equation of the rotationally symmetric aspherical surfaces is:

[0014]

[0015] In the surface equation of the rotationally symmetric aspheric surface, Z2 is the vector height of the rotationally symmetric aspheric surface, c is the curvature of the rotationally symmetric aspheric surface, k is the quadratic surface coefficient of the rotationally symmetric aspheric surface, r is the semi-aperture of the lens to which the rotationally symmetric aspheric surface belongs, and α1, α2, α3, α4, α5, α6, α7, and α8 are the coefficients of the second-order term, the fourth-order term, the sixth-order term, the tenth-order term, the twelfth-order term, the fourteenth-order term, and the sixteenth-order term, respectively. Specifically, the surface equation of the aspheric surface is an even-order aspheric surface, which is easier to process than an odd-order aspheric surface.

[0016] In some embodiments, the first quarter wave plate and the reflective polarizing element are combined into a stack and bonded to the bonding surface; or, the first quarter wave plate and the reflective polarizing element are combined into a stack and fixed on the lens barrel; or, the first quarter wave plate and the reflective polarizing element are respectively bonded to different bonding surfaces; or, the first quarter wave plate and the reflective polarizing element are arranged at intervals and respectively fixed on the lens barrel; or, one of the first quarter wave plate and the reflective polarizing element is fixed on the lens barrel, and the other is bonded to the bonding surface. Specifically, the situation where multiple optical films are bonded to different bonding surfaces after being split can avoid the problem of overall waste of composite films due to poor bonding of composite films. The situation where multiple optical films are bonded together on the same bonding surface is conducive to reducing the number of bonding times.

[0017] In some embodiments, the plurality of lenses include a first lens, a second lens, and a third lens arranged in sequence from the object side to the image side, the beam splitter is located on the object side of the first lens, and the object side of the third lens is a bonding surface. In this way, when the beam splitter is arranged on the object side of the lens closer to the object side, and the first quarter wave plate and the reflective polarization element are bonded to the object side of the lens closer to the image side, it is possible to prevent the first quarter wave plate and the reflective polarization element from being exposed to the outside, and to maximize the folding of the optical path.

[0018] In some embodiments, the reflective polarizing element and the first quarter wave plate are combined into a stack and bonded to the object side surface of the third lens. In this way, bonding the first quarter wave plate and the reflective polarizing element together on the same bonding surface helps to reduce the number of bonding times and the number of bonding surfaces, thereby avoiding introducing too many bonding surfaces to affect the imaging quality.

[0019] In some embodiments, the lens assembly further comprises a first linear polarizer, which is bonded to the surface of the reflective polarizing element close to the image side, and the first linear polarizer, the reflective polarizing element and the first quarter wave plate are combined into a stack and bonded to the object side of the third lens. The provision of the first linear polarizer is conducive to removing stray light, reducing stray light from entering the human eye, and facilitating the user to obtain a high-definition imaging picture. The first linear polarizer, the reflective polarizing element and the first quarter wave plate are combined into a stack and bonded to the same bonding surface, which is conducive to reducing the number of bonding times and the number of bonding surfaces, thereby avoiding the introduction of too many bonding surfaces to affect the imaging quality. In other embodiments, the first linear polarizer may also be independent of the reflective polarizing element and bonded to the bonding surface, or the first linear polarizer may be independent of the reflective polarizing element and fixed to the lens barrel.

[0020] In some embodiments, the lens assembly further includes an anti-reflection film, which is bonded to the surface of the first quarter wave plate close to the object side, and the reflective polarizing element, the first quarter wave plate and the anti-reflection film are combined into a stack and bonded to the object side surface of the third lens. The provision of the anti-reflection film is beneficial to reducing the reflection of incident light and improving the light efficiency of the optical system. The reflective polarizing element, the first quarter wave plate and the anti-reflection film are combined into a stack and bonded to the same bonding surface, which is also beneficial to reducing the number of bonding times and the number of bonding surfaces, thereby avoiding the introduction of too many bonding surfaces and affecting the imaging quality. In other embodiments, the anti-reflection film is independent of the first quarter wave plate and bonded to the bonding surface, or the anti-reflection film is independent of the first quarter wave plate and fixed to the lens barrel.

[0021] In some embodiments, the lens assembly further includes an anti-reflection film and a first linear polarizer, the anti-reflection film is attached to the surface of the first quarter-wave plate close to the object side, the first linear polarizer is attached to the surface of the reflective polarizer close to the image side, the first linear polarizer, the reflective polarizer, the first quarter-wave plate and the anti-reflection film are combined into a stack and attached to the object side surface of the third lens. In this way, the number of attachment times and the number of attachment surfaces are reduced, thereby avoiding the introduction of too many attachment surfaces to affect the imaging quality.

[0022] In some embodiments, the transmittance of the spectroscopic element to light with a wavelength of 380nm to 1000nm is 10% to 90%, and the reflectivity of the light with a wavelength of 380nm to 1000nm is 10% to 90%; and / or, the reflective polarizing element has a reflectivity of 75% to 100% to one of the p-linear polarized light and the s-linear polarized light in the light with a wavelength of 380nm to 1000nm, and a transmittance of 75% to 100% to the other of the p-linear polarized light and the s-linear polarized light in the light with a wavelength of 380nm to 1000nm, but is not limited to this.

[0023] In some embodiments, the center thickness of each lens ranges from 0.8 mm to 12 mm, and the edge thickness of each lens ranges from 0.8 mm to 12 mm, but is not limited thereto.

[0024] In some embodiments, the plurality of lenses include convex lenses and / or concave lenses; when the plurality of lenses include convex lenses, the ratio of the center thickness to the edge thickness of the convex lenses is less than 7:1; when the plurality of lenses include concave lenses, the ratio of the center thickness to the edge thickness of the concave lenses is greater than 1:7. Specifically, the greater the thickness ratio, the more uneven the shrinkage during lens molding, and the more difficult it is to mold high-precision lenses. In the embodiments of the present application, by using a mixed optical path with multiple surface shapes, the thickness ratio of the lens is reduced, the processing technology of the lens is improved, and the weight of the optical system is reduced.

[0025] In some embodiments, the first linear polarizer has a transmittance of 70% to 100% for one of the p-polarized light and the s-polarized light in the light with a wavelength of 380nm to 1000nm, and an absorptivity of 70% to 100% for the other of the p-polarized light and the s-polarized light in the light with a wavelength of 380nm to 1000nm, but is not limited thereto.

[0026] In some embodiments, the reflectivity of the anti-reflection film to light with a wavelength of 380 nm to 1000 nm is less than or equal to 5%, but the invention is not limited thereto.

[0027] In some embodiments, the image light incident on the lens assembly is linearly polarized light, and the lens assembly further includes a second quarter-wave plate located on a side of the beam splitter element close to the object side.

[0028] In some embodiments, the image light incident on the lens assembly is non-polarized light, and the lens assembly further comprises a second linear polarizer located on a side of the second quarter wave plate away from the beam splitter element. The second linear polarizer is used to convert the image light into linear polarized light, and the second quarter wave plate is used to convert the linear polarized light into circularly polarized light.

[0029] In some embodiments, the second linear polarizer has a transmittance of 70% to 100% for one of the p-polarized light and the s-polarized light in the light with a wavelength of 380nm to 1000nm, and an absorptivity of 70% to 100% for the other of the p-polarized light and the s-polarized light in the light with a wavelength of 380nm to 1000nm, but is not limited thereto.

[0030] A second aspect of the present application provides an optical system, comprising:

[0031] The lens assembly of the first aspect of the present application; and

[0032] The display is located at the object side of the lens assembly, and is used for emitting image light toward the lens assembly.

[0033] The optical system of the second aspect of the present application has at least the same advantages as the lens assembly of the first aspect, which will not be described in detail here.

[0034] In some embodiments, the lens assembly of the optical system has a first symmetry axis and a second symmetry axis that are perpendicular to each other, and the intersection of the first symmetry axis and the second symmetry axis is the optical axis center of the lens assembly; the display area of ​​the display is asymmetric about at least one of the first symmetry axis and the second symmetry axis. Specifically, the display of the optical system may have at least one of a horizontal offset, a vertical offset, and a rotational offset compared to the optical axis of the lens assembly, so that in the optical system, the display area is asymmetric about at least one of the first symmetry axis and the second symmetry axis of the lens assembly, so that when the above optical system is applied to a display device, part of the virtual image is imagined by the user through binocular stereoscopic vision, which is equivalent to enlarging the display content of the display in a disguised manner; and since the inherent resolution of the two displays in the display device itself remains unchanged, it is equivalent to providing additional visible resolution and additional field of view angle, which is conducive to the improvement of angular resolution. In addition, by enlarging the display content of the display in a disguised manner, the color deviation problem caused by the large optical focal length of the optical system can also be avoided.

[0035] In some embodiments, the display area has a third symmetry axis and a fourth symmetry axis that are perpendicular to each other; the third symmetry axis can be obtained by rotating the first symmetry axis by a preset angle and / or translating the first distance in a direction parallel to the second symmetry axis, the range of the preset angle is (-90°, 90°), when the third symmetry axis is in the counterclockwise direction of the first symmetry axis, the value of the preset angle is negative, and when the third symmetry axis is in the clockwise direction of the first symmetry axis, the value of the preset angle is positive; the range of the first distance is [0, 0.5*L), L is the size of the display area in a direction parallel to the second symmetry axis; the fourth symmetry axis can be obtained by rotating the second symmetry axis by a preset angle and / or translating the second distance in a direction parallel to the first symmetry axis, the range of the second distance is [0, 0.5*W), W is the size of the display area in a direction parallel to the first symmetry axis. Specifically, when the preset angle, the first distance, and the second distance exceed the above range, the user's eyes will not be able to fuse to obtain an image.

[0036] In some embodiments, when the lens assembly includes the second quarter-wave plate but does not include the second linear polarizer, the image light is linearly polarized light, the second quarter-wave plate is located between the beam splitting element and the display, and the second quarter-wave plate is used to convert the image light into circularly polarized light; the second quarter-wave plate is fixed to the lens barrel, or the second quarter-wave plate is attached to the display.

[0037] In some embodiments, when the lens assembly includes the second quarter-wave plate and the second linear polarizer, the image light is non-polarized light, the second quarter-wave plate and the second linear polarizer are both located between the beam splitting element and the display, the second linear polarizer is used to convert the image light into linear polarized light, and the second quarter-wave plate is used to convert the linear polarizer into circularly polarized light; the second quarter-wave plate and the second linear polarizer are arranged at intervals and are respectively fixed on the lens barrel; or, the second quarter-wave plate and the second linear polarizer are combined into a stack and fixed on the lens barrel; or, the second quarter-wave plate is fixed on the lens barrel, and the second linear polarizer is adhered to the display; or, the second quarter-wave plate and the second linear polarizer are combined into a stack and adhered to the display.

[0038] In some embodiments, the display is any one of an organic light emitting diode display, a liquid crystal display, a micro inorganic light emitting diode display, a silicon-based liquid crystal display, a digital light processing display, and a laser beam scanner, but is not limited thereto.

[0039] In some embodiments, the size of the display area is no larger than 7 inches, so as to obtain a display device that is small in size, light in weight, and can be worn for a long time.

[0040] In some embodiments, the number of pixels per inch of the display is not less than 400, so as to reduce the graininess of the picture and improve the user's immersion and visual clarity when using the display device.

[0041] In some embodiments, the refresh rate of the display is not less than 30 Hz, so as to improve the picture smoothness and response speed of the display.

[0042] A third aspect of the present application provides a display device, comprising:

[0043] a housing; and

[0044] A first optical system and a second optical system mounted on the housing;

[0045] Among them, the first optical system and the second optical system are the optical systems of the second aspect of the present application.

[0046] The display device of the third aspect of the present application has at least the same advantages as the optical system of the second aspect of the present application, which will not be described in detail here.

[0047] In some embodiments, when the user wears the display device, the first optical system corresponds to the user's left eye, the second optical system corresponds to the user's right eye, and the display area of ​​the first optical system and the display area of ​​the second optical system both have a third symmetry axis and a fourth symmetry axis; in the first optical system, the third symmetry axis can be obtained by rotating the first symmetry axis counterclockwise and / or translating along the user's nose bridge to the user's forehead, and the fourth symmetry axis can be obtained by rotating the second symmetry axis counterclockwise and / or translating along the user's right eye to the user's left eye; in the second optical system, the third symmetry axis can be obtained by rotating the first symmetry axis clockwise and / or translating along the user's forehead to the user's nose bridge, and the fourth symmetry axis can be obtained by rotating the second symmetry axis clockwise and / or translating along the user's left eye to the user's right eye. Due to the offset of the two displays in the display device, the distance between the two displays is pulled apart, and the space between the two displays is larger, and this part of the space can be used to arrange other mechanisms (such as heat dissipation mechanisms or interpupillary distance adjustment mechanisms). BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1A It is a schematic structural diagram of a display device according to the first embodiment of the present application.

[0049] Figure 1B for Figure 1A Schematic diagram of imaging of a display device.

[0050] Figure 1C It is a schematic structural diagram of the optical system of the first embodiment of the present application.

[0051] Figure 2 It is a schematic structural diagram of an optical system according to the second embodiment of the present application.

[0052] Figure 3 It is a schematic structural diagram of an optical system according to the third embodiment of the present application.

[0053] Figure 4 It is a schematic structural diagram of an optical system according to the fourth embodiment of the present application.

[0054] Figure 5 It is a schematic structural diagram of an optical system according to the fifth embodiment of the present application.

[0055] Figure 6 It is a schematic structural diagram of an optical system according to the sixth embodiment of the present application.

[0056] Figure 7 It is a schematic structural diagram of the optical system of the seventh embodiment of the present application.

[0057] Figure 8 It is a schematic structural diagram of the optical system of the eighth embodiment of the present application.

[0058] Fig. 9 It is a schematic structural diagram of an optical system according to the ninth embodiment of the present application.

[0059] Fig.10 It is a schematic structural diagram of an optical system according to the tenth embodiment of the present application.

[0060] Fig.11 It is a schematic structural diagram of the optical system of the eleventh embodiment of the present application.

[0061] Fig.12 This is a schematic diagram of imaging of a display device according to the second embodiment of the present application.

[0062] Fig.13 It is a schematic diagram of imaging of a display device according to the third embodiment of the present application.

[0063] Fig.14 It is a schematic diagram of imaging of a display device according to the fourth embodiment of the present application.

[0064] Fig.15 It is a schematic diagram of imaging of a display device according to the fifth embodiment of the present application.

[0065] Fig.16 A modulation transfer function diagram of a display device according to an embodiment of the present application.

[0066] Fig.17 A grid distortion diagram of a display device according to an embodiment of the present application.

[0067] Description of main component symbols:

[0068] Display devices 1000a, 1000b, 1000c, 1000d, 1000e

[0069] First optical system 100a, 100b, 100c, 100d, 100e

[0070] Second optical systems 200a, 200b, 200c, 200d, 200e

[0071] Housing 300

[0072] Optical system 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k

[0073] Display 110

[0074] First display 111

[0075] Second display 112

[0076] Lens assemblies 120, 120a, 120b, 120c, 120d, 120e, 120f, 120g, 120h, 120i, 120j, 120k

[0077] The first lens assembly 121

[0078] The second lens assembly 122

[0079] Lens group 10

[0080] First lens 11

[0081] The second lens 12

[0082] The third lens 13

[0083] Spectral element 20

[0084] First polarization modulation components 30a, 30b, 30c, 30d

[0085] First quarter wave plate 31

[0086] Reflective polarizing element 32

[0087] The first linear polarizing plate 33

[0088] Anti-reflection film 34

[0089] The second polarization modulation component 40

[0090] Second linear polarizing plate 41

[0091] Second quarter wave plate 42

[0092] Human Eye

[0093] First optical surface S1

[0094] Second optical surface S2

[0095] The third optical surface S3

[0096] Fourth optical surface S4

[0097] Fifth optical surface S5

[0098] Sixth optical surface S6

[0099] First direction X

[0100] Second direction Y

[0101] The third direction Z

[0102] Display Area AA

[0103] Optical axis center O1

[0104] Geometric center O2

[0105] The first symmetry axis A1

[0106] The second symmetry axis A2

[0107] The third symmetry axis A3

[0108] Fourth symmetry axis A4

[0109] The first angle θ1

[0110] The second angle θ2

[0111] First distance D1

[0112] The second distance D2

[0113] The third distance D3

[0114] Fourth distance D4

[0115] Left visible range VAL

[0116] Right Visible Range VAR

[0117] Binocular visual range VA1, VA2, VA3, VA4, VA5 DETAILED DESCRIPTION

[0118] The optical system of existing VR display devices has a small field of view (FOV), a long total track length (TTL), and a low number of pixels per degree (PPD). In particular, when display devices use small-size displays, as the field of view increases, the image quality in the edge area decreases, the distortion is large, the screen utilization rate is low, the optical design is more difficult, and the lens surface is not conducive to processing and manufacturing. In order to optimize the image quality, the surface of the lens used to bond the optical film is usually an arc surface (such as a spherical or aspherical surface), and the curved bonding process is difficult. Moreover, as the radius of curvature of the lens decreases, the performance of optical film layers such as quarter-wave plates and reflective polarizing elements decreases, which will not only cause problems such as color deviation and uniformity, but may even cause problems such as orange peel wrinkles, bubbles, and inability to bond in the optical film layer.

[0119] In this regard, embodiments of the present application provide a lens assembly, an optical system, and a display device to solve at least one of the above problems.

[0120] The first aspect of the present application provides a lens assembly. The lens assembly includes a lens barrel, a plurality of lenses arranged in sequence from the object side to the image side, a beam splitter arranged in sequence from the object side to the image side, a first quarter wave plate and a reflective polarizing element. The plurality of lenses, the beam splitter, the first quarter wave plate and the reflective polarizing element are all located in the lens barrel, and are all located on the optical path between the object side and the image side. Each lens includes an object side surface and an image side surface that are arranged opposite to each other, the object side surface of each lens faces the object side, and the image side surface of each lens faces the image side. Among them, at least one of the first quarter wave plate and the reflective polarizing element is fixed on the lens barrel independently of the plurality of lenses; or, the object side surface and the image side surface of the plurality of lenses include at least one bonding surface, and at least one of the first quarter wave plate and the reflective polarizing element is bonded to the bonding surface, and the bonding surface is a quadratic surface with zero curvature in at least one direction.

[0121] In the lens assembly of the first aspect of the present application, when the first quarter wave plate and / or the reflective polarizing element are fixed on the lens barrel, the problems of color deviation, uniformity reduction, orange peel wrinkles, bubbles, inability to bond, etc. of the first quarter wave plate and / or the reflective polarizing element after bonding caused by the existing bending bonding process can be directly avoided. When the first quarter wave plate and / or the reflective polarizing element are bonded to the bonding surface, the bonding surface is a quadratic surface with zero curvature in at least one direction, which is conducive to reducing the difficulty of bonding the first quarter wave plate and / or the reflective polarizing element to the lens through the bending bonding process, and is conducive to solving the problems of color deviation, uniformity reduction, orange peel wrinkles, bubbles, inability to bond, etc. of the first quarter wave plate and / or the reflective polarizing element after bonding using the bending bonding process.

[0122] The second aspect of the present application provides an optical system. The optical system comprises the lens assembly of the first aspect of the present application; and a display. The display is located on the object side of the lens assembly, and the display is used to emit image light to the lens assembly.

[0123] The optical system of the second aspect of the present application has at least the same advantages as the lens assembly of the first aspect, which will not be described in detail here.

[0124] The third aspect of the present application provides a display device. The display device includes a housing and a first optical system and a second optical system mounted on the housing. The first optical system and the second optical system are the optical systems of the second aspect of the present application.

[0125] The display device of the third aspect of the present application has at least the same advantages as the optical system of the second aspect of the present application, which will not be described in detail here.

[0126] For ease of understanding, some technical terms involved in the embodiments of the present application are explained below.

[0127] The optical axis refers to a ray of light that passes vertically through the center of an ideal lens.

[0128] The object side is defined by the lens assembly, and the side where the object is located is the object side. In the embodiment of the present application, the object is a display, and the side where the display is located is the object side.

[0129] The image side is defined by the lens assembly, and the side where the image of the object is located is the image side. In the embodiment of the present application, the side where the image of the object is located is the observation side, that is, the side where the human eye is located.

[0130] Object side: the surface of the lens facing the object side is called the object side.

[0131] Image side: The surface of the lens facing the image side is called the image side.

[0132] The bonding surface is the surface of the lens bonded with an optical film, and the optical film may be any one of a quarter wave plate, a reflective polarizer, an anti-reflection film, and a linear polarizer, or a combination of two or more thereof, and in the embodiment of the present application, the bonding surface is a quadratic surface with zero curvature in at least one direction. For example, the bonding surface may be a developable surface.

[0133] A developable surface is a surface where the Gaussian curvature is zero at every point on the surface. A developable surface can be bent without stretching or compressing, or in other words, a developable surface is a surface that can be made by transforming a plane (transformations include folding, bending, rolling, cutting and / or gluing). For example, a cylinder or a cone are both developable surfaces.

[0134] A spherical surface refers to an optical surface with a constant curvature from the center to the edge of the lens.

[0135] A rotationally symmetric aspheric surface refers to an optical surface that has a curvature that changes from the center to the edge of the lens.

[0136] A free-form surface refers to an optical surface that does not have axial rotational symmetry or translational symmetry constraints.

[0137] The total optical length refers to the total length from the imaging surface of the optical system to the light emitting surface of the display.

[0138] Refresh rate refers to the number of times the display refreshes the displayed content per unit time.

[0139] The number of pixels per angle refers to the average number of pixels filled within every 1° angle in the field of view, also known as angular resolution.

[0140] The focal power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam. It characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal power, the stronger the ability to bend light. The smaller the absolute value of the focal power, the weaker the ability to bend light. When the focal power is a positive number, the refraction of light is convergent; when the focal power is a negative number, the refraction of light is divergent.

[0141] The field of view refers to the angle between the edge of the part of the image formed by the display device that can be observed by the human eye and the line connecting the center of the human pupil, including the horizontal field of view, vertical field of view, diagonal field of view, etc. In layman's terms, the field of view is the maximum visible range of the virtual image in the horizontal, vertical and diagonal directions. The larger the field of view, the stronger the sense of immersion.

[0142] In the examples of the present application, unless otherwise specified, the numerical range includes the endpoint values.

[0143] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0144] like Figure 1A As shown, the display device 1000a of the first embodiment of the present application includes a first optical system 100a, a second optical system 200a and a housing 300. The first optical system 100a and the second optical system 200a are both mounted on the housing 300. Specifically, the housing 300 includes a receiving cavity (not shown), and the first optical system 100a and the second optical system 200a are both received in the receiving cavity. The display device 1000a is a virtual reality display device. When a user wears the display device 1000a, the first optical system 100a corresponds to the user's left eye, and the second optical system 200a corresponds to the user's right eye. The user can observe a virtual image through the display device 1000a.

[0145] It is understandable that the display device 1000a also includes other hardware such as a processor, a controller, and a battery.

[0146] Figure 1A The display device 1000a shown in the figure is in the form of glasses. In other embodiments, the display device 1000a may also be in the form of a helmet.

[0147] For the convenience of description, it is defined that when a user wears the display device 1000a, the direction from the user's left eye to the user's right eye is the positive direction of the first direction X (or the direction from the first optical system 100a to the second optical system 200a is the positive direction of the first direction X), the direction from the user's nose bridge to the user's forehead is the positive direction of the second direction Y, and the direction from the first optical system 100a and / or the second optical system 200a to the user is the positive direction of the third direction Z. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other. The first direction is also referred to as the horizontal direction or the left-right direction, and the second direction is referred to as the vertical direction or the up-down direction.

[0148] like Figure 1B As shown in FIG. 1( b), the first optical system 100a includes a display 110 and a lens assembly 120. The display 110 includes a display area AA for emitting image light to the lens assembly 120. After the image light of the display 110 passes through the lens assembly 120 of the first optical system 100a, it forms a light beam on the left eye of the user. Figure 1B The left visible range VAL shown in Figure (a).

[0149] The second optical system 200a has the same structure as the first optical system 100a. Specifically, the second optical system 200a includes a display 110 and a lens assembly 120. The display 110 includes a display area AA for emitting image light to the lens assembly 120. After the image light of the display 110 passes through the lens assembly 120 of the second optical system 200a, it forms a display image on the user's right eye. Figure 1B The right visible range VAR is shown in (a) of FIG. After the left visible range VAL and the right visible range VAR are superimposed, the binocular visible range VA1 is obtained.

[0150] The first optical system 100a and the second optical system 200a are both folded optical path type optical systems, or in other words, pancake type optical systems. Figures 1C to 11 Specifically, the schematic diagrams of the structures of the optical systems of different embodiments are as follows. The first optical system 100a and the second optical system 200a can be as follows Figures 1C to 11 An optical system according to any one of the embodiments and its variations.

[0151] like Figure 1C As shown, the optical system 1a of the first embodiment of the present application includes a display 110 and a lens assembly 120a. The display 110 is located on the object side of the lens assembly 120a, and the human eye E is located on the image side of the lens assembly 120a. The display 110 is used to emit image light to the lens assembly 120a. The lens assembly 120a is located on the optical path of the image light and is used to fold the optical path to reduce the total optical length of the optical system 1a.

[0152] The display 110 is any one of an organic light-emitting diode (OLED) display, a liquid crystal display (LCD), a micro light-emitting diode (Micro LED) display, a liquid crystal on silicon (LCoS) display, a digital light processing (DLP) display, and a laser beam scanner (LBS).

[0153] In some embodiments, the size of the display area AA of the display 110 is no greater than 7 inches, so as to obtain a display device that is small in size, light in weight, and can be worn for a long time. Moreover, the smaller the size of the display area AA of the display 110, the more conducive it is for the display device to be prepared in the form of AR glasses.

[0154] In some embodiments, the pixel per inch (PPI) of the display 110 is not less than 400, so as to reduce the graininess of the picture and improve the user's immersion and visual clarity when using the display device.

[0155] In some embodiments, the refresh rate of the display 110 is not less than 30 Hz, so as to improve the picture smoothness and response speed of the display.

[0156] The lens assembly 120 a includes a lens barrel (not shown), and a lens group 10 , a beam splitter 20 , a first polarization modulation component 30 a , and a second polarization modulation component 40 , all of which are located in the lens barrel.

[0157] The lens group 10 includes a first lens 11, a second lens 12 and a third lens 13 arranged in sequence from the object side to the image side. The first lens 11 includes a first optical surface S1 and a second optical surface S2 relative to each other. The second lens 12 includes a third optical surface S3 and a fourth optical surface S4 relative to each other. The third lens 13 includes a fifth optical surface S5 and a sixth optical surface S6 relative to each other. The first optical surface S1, the third optical surface S3 and the fifth optical surface S5 are all facing the object side, and the second optical surface S2, the fourth optical surface S4 and the sixth optical surface S6 are all facing the image side. The first optical surface S1, the third optical surface S3 and the fifth optical surface S5 are respectively the object side surfaces of the first lens 11, the second lens 12 and the third lens 13, and the second optical surface S2, the fourth optical surface S4 and the sixth optical surface S6 are respectively the image side surfaces of the first lens 11, the second lens 12 and the third lens 13.

[0158] The second polarization modulation component 40 is located between the display 110 and the beam splitter 20, and is used to convert the image light emitted by the display 110 into circularly polarized light. Specifically, in the optical system 1a, the image light emitted by the display 110 is non-polarized light, and the second polarization modulation component 40 includes a second linear polarizer 41 and a second quarter-wave plate 42 arranged from the object side to the image side. The second linear polarizer 41 is used to convert the image light emitted by the display 110 into linearly polarized light, and the second quarter-wave plate 42 is used to convert the linearly polarized light into circularly polarized light.

[0159] In some embodiments, the second linear polarizer 41 has a transmittance of 70% to 100% for one of the p-polarized light and the s-polarized light in the light with a wavelength of 380nm to 1000nm (i.e., visible light to near-infrared light), and an absorptivity of 70% to 100% for the other of the p-polarized light and the s-polarized light in the light with a wavelength of 380nm to 1000nm, but is not limited thereto.

[0160] In other embodiments, the image light emitted by the display 110 is linearly polarized light, and the second linear polarizer 41 of the second polarization modulation component 40 can be omitted. That is, the second polarization modulation component 40 includes a second quarter wave plate 42, but does not include a second linear polarizer 41. The second linear polarizer 41 is located between the display 110 and the beam splitter 20, and is used to convert the linear polarized light emitted by the display 110 into circularly polarized light.

[0161] The spectroscopic element 20 is used to reflect part of the incident light and transmit the other part. In some embodiments, the transmittance of the spectroscopic element 20 for light with a wavelength of 380nm to 1000nm is 10% to 90%, and the reflectance for light with a wavelength of 380nm to 1000nm is 10% to 90%. Specifically, the spectroscopic element 20 can be a semi-transparent and semi-reflective film, which is provided on the first optical surface S1 by evaporation, for example, and the ratio of its transmittance to reflectivity for light with a wavelength of 380nm to 1000nm is 5:5, but is not limited thereto. In other embodiments, the ratio of the transmittance to reflectivity of the spectroscopic element 20 for light with a wavelength of 380nm to 1000nm can also be 4:6 or 3:7, etc.

[0162] The first polarization modulation component 30a is located on the side of the light splitting element 20 away from the display 110. The first polarization modulation component 30a includes a first quarter wave plate 31 and a reflective polarization element 32 arranged in sequence from the object side to the image side. The first quarter wave plate 31 and the reflective polarization element 32 are both located between the second lens 12 and the third lens 13.

[0163] The first quarter wave plate 31 has the function of making the phase difference between the ordinary light and the extraordinary light emitted by a certain wavelength 1 / 4 wavelength when the light is vertically incident and passed through, and can change the linear polarized light into circular polarized light or elliptically polarized light or vice versa in the optical path. Specifically, the first quarter wave plate 31 is used to change the polarization state of the incident light, so that the light incident to the reflective polarizing element 32 can be smoothly reflected or transmitted by the reflective polarizing element 32.

[0164] The reflective polarizing element 32 is used to selectively reflect and transmit polarized light. In some embodiments, the reflective polarizing element 32 is a film that reflects s-linear polarized light and transmits p-linear polarized light. In other embodiments, the reflective polarizing element 32 is a film that reflects p-linear polarized light and transmits s-linear polarized light. Specifically, the reflective polarizing element has a reflectivity of 75% to 100% for one of p-linear polarized light and s-linear polarized light in light with a wavelength of 380nm to 1000nm, and a transmittance of 75% to 100% for the other of p-linear polarized light and s-linear polarized light in light with a wavelength of 380nm to 1000nm, but is not limited thereto.

[0165] In the optical system 1a of the first embodiment of the present application, the fifth optical surface S5 of the third lens 13 is a bonding surface, and its surface equation (Formula 1 for short) is:

[0166]

[0167] In formula 1, Rx is the curvature radius of the bonding surface in the first direction X, Ry is the curvature radius of the bonding surface in the second direction Y, Z1 is the vector height of the bonding surface in the third direction Z, kx and ky are cone coefficients, and the value of one of Rx and Ry is infinite.

[0168] The first quarter wave plate 31 and the reflective polarizing element 32 are combined into a stack (or a two-in-one composite film layer, or a relatively fixed combination of the first quarter wave plate 31 and the reflective polarizing element 32 ) and attached to the fifth optical surface S5 .

[0169] In the optical system 1a of the first embodiment of the present application, Rx is infinite, and the fifth optical surface S5 has a change in curvature in the second direction Y. In this way, the fifth optical surface S5 is a quadratic surface with zero curvature in at least one direction. Compared with the first quarter wave plate and / or the reflective polarizing element being bonded to a spherical surface or a rotationally symmetric aspherical surface, the first quarter wave plate and / or the reflective polarizing element being bonded to the above bonding surface, it is helpful to reduce the difficulty of bonding the first quarter wave plate and the reflective polarizing element to the lens through a curved bonding process, and it is helpful to solve the problems of orange peel wrinkles, bubbles, and inability to bond the first quarter wave plate and / or the reflective polarizing element after bonding using the curved bonding process, thereby improving the bonding yield rate and further improving the imaging quality of the optical system.

[0170] In some embodiments, the object side and image side of the multiple lenses of the lens group 10 may also include at least one of a spherical surface, a rotationally symmetric aspherical surface, and a Fresnel surface. Specifically, the spherical surface is conducive to lens processing and has low cost. Compared with the spherical surface, the rotationally symmetric aspherical surface is conducive to correcting the spherical aberration of the imaging and improving the imaging quality. Compared with the spherical surface and the rotationally symmetric aspherical surface, the Fresnel surface has a short focal length, a small size, a light weight, and a compact structure.

[0171] In the optical system 1a of the first embodiment of the present application, the first optical surface S1, the second optical surface S12, the third optical surface S13, and the fourth optical surface S14 are all rotationally symmetric aspherical surfaces, and the rotationally symmetric aspherical surfaces may be even-order aspherical surfaces, and their surface equations (referred to as Formula 2) are:

[0172]

[0173] In Formula 2, Z2 is the vector height of the rotationally symmetric aspheric surface in the third direction Z, c is the curvature of the rotationally symmetric aspheric surface, k is the quadratic surface coefficient of the rotationally symmetric aspheric surface, r is the semi-aperture of the lens to which the rotationally symmetric aspheric surface belongs, and α1, α2, α3, α4, α5, α6, α7, and α8 are coefficients of the second-order term, the fourth-order term, the sixth-order term, the tenth-order term, the twelfth-order term, the fourteenth-order term, and the sixteenth-order term, respectively. The rotationally symmetric aspheric surface is an even-order aspheric surface, which is easier to process than the odd-order aspheric surface.

[0174] In some embodiments, the object side and image side of the multiple lenses of the lens group 10 include at least one free-form surface. The free-form surface includes at least one of an extended polynomial surface, a Zernike polynomial surface and a Q-type polynomial surface. Specifically, the extended polynomial surface is obtained by adding various power terms of x and y on a quadratic surface basis, and its surface description is simple, the design freedom is high, and it is consistent with the form of CNC machining of optical surfaces. The Zernike polynomial surface has a direct correspondence with the aberration, which is conducive to the targeted correction of the aberration of the optical system according to the vector aberration theory. The surface coefficient of the Q-type polynomial surface can be directly used to characterize the gradient of the vector height deviation of the surface relative to the best fitting sphere, which can be used for the tolerance analysis of the free-form surface, so that the evaluation of the optical design and the difficulty of processing detection can be carried out simultaneously, thereby avoiding the cumbersome process of processing evaluation after design.

[0175] In summary, compared with traditional spherical and aspherical surfaces, free-form surfaces have no rotational symmetry and a high degree of design freedom, and can provide more design optimization variables. Therefore, the lens assembly of the embodiment of the present application has at least the following advantages: First, it is conducive to correcting distortion and increasing screen utilization; second, it is conducive to correcting aberrations, and then optimizing the surface shape of the lens to reduce the back curvature of the lens, thereby providing a suitable thickness ratio of the lens structure, so that the lens has a higher processing and manufacturing accuracy; third, it can increase the field of view angle and reduce the total optical length while solving the aberrations.

[0176] In the optical system 1a of the first embodiment of the present application, the sixth optical surface S6 of the third lens 13 is a free-form surface, and the sixth optical surface S6 is an extended polynomial surface, and its surface equation (referred to as Formula 3) is:

[0177]

[0178] In formula 3, r 2 =x 2 +y 2 , Z3 is the sagittal height of the free-form surface in the third direction Z, c is the curvature of the free-form surface, k is the quadratic surface coefficient of the free-form surface, N is the total number of polynomial coefficients, A i is the coefficient of the i-th expanded polynomial, E i (x, y) is a power series about x and y. For example, E1 is x, E2 is y, and E3 is x 2 , E4 is x*y, E5 is y 2 , E6 is x 3 , E7 is x 2 *y, E8 is x*y 2 , E9 is y 3, ..., and so on. Among them, the linear term has one term, the quadratic term has three terms, the cubic term has four terms, and so on. The data values ​​at the x and y positions will be divided by a normalized radius to obtain a polynomial coefficient without a quantity.

[0179] In summary, in the above optical system 1a, a free-form surface, a quadratic surface (i.e., the above-mentioned bonding surface) and an aspheric mixed optical path structure are used, and the design of the bonding surface shape can reduce the difficulty of the curve bonding process. The free-form surface can provide more optimization variables, which has the following advantages: first, it is conducive to increasing the field of view of the optical system; second, it is conducive to reducing the lens aperture, thereby reducing the weight of the optical system; third, it is conducive to reducing distortion and increasing screen utilization; fourth, it reduces the thickness ratio of the lens, improves the lens processing technology, and reduces the weight of the optical system.

[0180] In some embodiments, among the multiple lenses of the lens group 10, the center thickness (Center Thickness, CT) of each lens ranges from 0.8 mm to 12 mm, and the edge thickness (Edge Thickness, ET) of each lens ranges from 0.8 mm to 12 mm, but is not limited thereto.

[0181] In some embodiments, the multiple lenses of the lens group 10 include convex lenses and / or concave lenses. When the lens group 10 includes a convex lens, the ratio of the center thickness to the edge thickness of the convex lens is less than 7:1, and when the lens group 10 includes a concave lens, the ratio of the center thickness to the edge thickness of the concave lens is greater than 1:7, but not limited to this. It should be noted that the larger the thickness ratio, the more uneven the shrinkage during lens molding, and the more difficult it is to mold a high-precision lens. In the embodiment of the present application, by using a mixed optical path of multiple surface shapes, the thickness ratio of the lens is reduced.

[0182] The working principle of the optical system 1a is as follows: the non-polarized light emitted by the display 110 is converted into the first linear polarized light (such as p-linear polarized light with a vibration direction parallel to the incident plane) after passing through the second linear polarizing plate 41, and the first linear polarized light is converted into the first circular polarized light (such as right-handed circular polarized light) after passing through the second quarter wave plate 42. After passing through the beam splitter 20, part of the first circular polarized light is reflected, and the other part is transmitted, and then passes through the first lens 11, the second lens 12, and the first quarter wave plate 31 in sequence to convert it into the first linear polarized light. Among them, the reflective polarizing element 32 is a film that reflects the first linear polarized light and transmits the second linear polarized light. Therefore, the first linear polarized light converted from the first quarter wave plate 31 is reflected again to the first quarter wave plate 31 after passing through the reflective polarizing element 32, and becomes the first circular polarized light after passing through the first quarter wave plate 31. After the first circularly polarized light converted from the first quarter wave plate 31 passes through the second lens 12 and the first lens 11, part of it is transmitted by the beam splitter 20, and the other part is reflected by the beam splitter 20 as a second circularly polarized light (such as left-handed circularly polarized light). After the second circularly polarized light passes through the first lens 11, the second lens 12, and the first quarter wave plate 31 in sequence, it becomes a second linearly polarized light (such as s-linear polarized light with a vibration direction perpendicular to the incident plane), and the second linearly polarized light is incident on the human eye after being transmitted through the reflective polarizing element 32. In other embodiments, the first linearly polarized light may be s-linearly polarized light, the second linearly polarized light may be p-linearly polarized light, the first circularly polarized light is left-handed circularly polarized light, and the second circularly polarized light is right-handed circularly polarized light.

[0183] like Figure 2 As shown, the difference between the optical system 1b of the second embodiment of the present application and the optical system 1a of the first embodiment is that the first polarization modulation component 30b of the lens assembly 120b also includes a first linear polarizer 33, and the first linear polarizer 33 is located on the side of the reflective polarization element 32 close to the image side. In the optical system 1b, the first quarter wave plate 31, the reflective polarization element 32, and the first linear polarizer 33 are arranged in sequence from the object side to the image side, and constitute a stack (i.e., a three-in-one composite film layer) and are attached to the fifth optical surface S5. The first linear polarizer 33 is used to remove stray light and reduce stray light from entering the human eye, which is beneficial for the user to obtain a high-definition imaging picture. In some embodiments, the first linear polarizer 33 has a transmittance of 70% to 100% for one of the p-linear polarized light and the s-linear polarized light in the light with a wavelength of 380nm to 1000nm, and an absorptivity of 70% to 100% for the other of the p-linear polarized light and the s-linear polarized light in the light with a wavelength of 380nm to 1000nm, but is not limited thereto.

[0184] like Figure 3As shown, the difference between the optical system 1c of the third embodiment of the present application and the optical system 1a of the first embodiment is that the first polarization modulation component 30c of the lens assembly 120c also includes an anti-reflection film 34, and the anti-reflection film 34 is located on the side of the first quarter wave plate 31 close to the object side. In the optical system 1c, from the object side to the image side, the anti-reflection film 34, the first quarter wave plate 31, and the reflective polarization element 32 are arranged in sequence, and form a stack (i.e., a three-in-one composite film layer) and are attached to the fifth optical surface S5. The anti-reflection film 34 is used to reduce the reflection of the incident light and improve the light efficiency of the optical system. In some embodiments, the reflectivity of the anti-reflection film 34 to light with a wavelength of 380nm to 1000nm is less than or equal to 5%, but is not limited to this.

[0185] like Figure 4 As shown, the difference between the optical system 1d of the fourth embodiment of the present application and the optical system 1a of the first embodiment is that the first polarization modulation component 30d of the lens assembly 120d further includes a first linear polarizer 33 and an anti-reflection film 34, the first linear polarizer 33 is located on the side of the reflective polarizing element 32 close to the image side, and the anti-reflection film 34 is located on the side of the first quarter wave plate 31 close to the object side. In the optical system 1d, from the object side to the image side, the anti-reflection film 34, the first quarter wave plate 31, the reflective polarizing element 32, and the first linear polarizer 33 are arranged in sequence and constitute a stack (i.e., a four-in-one composite film layer) and are attached to the fifth optical surface S5.

[0186] In other embodiments, the anti-reflection film in the lens assembly may be provided with multiple anti-reflection films. In addition, the anti-reflection film may also be formed on the optical surface of the lens by evaporation. For example, Figure 4 An anti-reflection film may also be evaporated on the second optical surface S2 of the first lens 11 to improve the utilization rate of light.

[0187] In the optical systems of the first to fourth embodiments above, the fifth optical surface S5 is a bonding surface. In other embodiments, the bonding surface may be any one of the second optical surface S2, the third optical surface S3, the fourth optical surface S4 and the sixth optical surface S6. The first polarization modulation component is bonded to the bonding surface as a composite film layer. Figure 5 To Attachment Figure 8 Specific instructions.

[0188] like Figure 5 As shown, the difference between the optical system 1e of the fifth embodiment of the present application and the optical system 1a of the first embodiment is that in the lens assembly 120e, the fourth optical surface S4 is a bonding surface, and the first polarization modulation component 30a is bonded to the fourth optical surface S4.

[0189] like Figure 6As shown, the difference between the optical system 1f of the sixth embodiment of the present application and the optical system 1a of the first embodiment is that in the lens assembly 120f, the third optical surface S3 is a bonding surface, and the first polarization modulation component 30a is bonded to the third optical surface S3.

[0190] like Figure 7 As shown, the difference between the optical system 1g of the seventh embodiment of the present application and the optical system 1a of the first embodiment is that in the lens assembly 120g, the second optical surface S2 is a bonding surface, and the first polarization modulation assembly 30a is bonded to the second optical surface S2.

[0191] like Figure 8 As shown, the difference between the optical system 1h of the eighth embodiment of the present application and the optical system 1a of the first embodiment is that in the lens assembly 120h, the sixth optical surface S6 is a bonding surface, and the first polarization modulation component 30a is bonded to the sixth optical surface S6.

[0192] Depend on Figure 1C It can be seen that in the optical system 1a, the distance by which the optical path is folded is approximately twice the distance from the beam splitter 20 to the reflective polarizing element 32. Therefore, when the distance between each two adjacent lenses in the optical system 1a, the optical system 1e, the optical system 1f, the optical system 1g, and the optical system 1h is the same, the distance by which the optical path is folded in the optical system 1a is greater than the distance by which the optical path is folded in the optical system 1e, the optical system 1f, and the optical system 1g, but less than the distance by which the optical path is folded in the optical system 1h. Therefore, when the sixth optical surface S6 is a bonding surface, it is more conducive to folding the optical path to the maximum extent than when any one of the first optical surface S1 to the fifth optical surface S5 is a bonding surface.

[0193] It should be noted that when the sixth optical surface S6 is a bonding surface, the first polarization modulation component 30a is exposed to the outside, and the reliability of the first polarization modulation component 30a will be affected. Therefore, when the fifth optical surface S5 is a bonding surface, it can not only prevent the first polarization modulation component 30a from being exposed to the outside, but also maximize the distance between the reflective polarization element and the beam splitter element, so that the transmission path of the light between the reflective polarization element and the beam splitter element is increased as much as possible, thereby folding the light path to the maximum extent, reducing the total optical length of the optical system, and obtaining an excellent optical effect in the entire field of view.

[0194] Understandably, Figures 5 to 8 The first polarization modulation component 30a can be replaced by any one of the first polarization modulation component 30b, the first polarization modulation component 30c, and the first polarization modulation component 30d mentioned above.

[0195] In the optical systems of the first to eighth embodiments above, an optical system having a bonding surface is used as an example for description. In other embodiments, one or more optical films in the first polarization modulation component and the second polarization modulation component (such as the first quarter wave plate, the reflective polarizer, the anti-reflection film, the first linear polarizer, the second linear polarizer, and the second quarter wave plate) can also be fixed on the lens barrel independently or in combination. The inner wall of the lens barrel is, for example, provided with a card slot, and the one or more optical films can be snapped into the card slot. In this way, it is helpful to avoid the problems of orange peel wrinkles, bubbles, and inability to bond when the existing curved bonding process is used to bond the optical film to the surface of the lens. In other embodiments, other mechanical structures can be provided on the lens barrel, and the one or more optical films can be fixed on the other mechanical structures. The following is combined with the attached Fig. 9 To Attachment Fig.11 Specific instructions.

[0196] like Fig. 9 and Figure 1C As shown, the difference between the optical system 1i of the ninth embodiment of the present application and the optical system 1a of the first embodiment is that the lens assembly 120i does not include a bonding surface, the first polarization modulation assembly 30a is located between the second lens 12 and the third lens 13, and the first quarter-wave plate 31 and the reflective polarization element 32 in the first polarization modulation assembly 30a are combined into a stack (or a two-in-one composite film layer) and fixed on the lens barrel.

[0197] like Fig.10 and Figure 6 As shown, the difference between the optical system 1j of the tenth embodiment of the present application and the optical system 1f of the sixth embodiment of the present application is that the lens assembly 120j does not include a bonding surface, the first polarization modulation assembly 30a is located between the first lens 11 and the second lens 12, and the first quarter-wave plate 31 and the reflective polarization element 32 in the first polarization modulation assembly 30a are combined into a stack (or a two-in-one composite film layer) and fixed on the lens barrel.

[0198] like Fig.11 and Figure 8 As shown, the difference between the optical system 1k of the eleventh embodiment of the present application and the optical system 1h of the eighth embodiment of the present application is that the lens assembly 120k does not include a bonding surface, the first polarization modulation assembly 30a is located on the side of the third lens 13 close to the image side, and the first quarter-wave plate 31 and the reflective polarization element 32 in the first polarization modulation assembly 30a are combined into a stack (or a two-in-one composite film layer) and fixed on the lens barrel.

[0199] Understandably, Figures 9 to 11 The first polarization modulation component 30a can be replaced by any one of the first polarization modulation component 30b, the first polarization modulation component 30c, and the first polarization modulation component 30d mentioned above.

[0200] In the optical systems of the first to eleventh embodiments and their modified examples, the first polarization modulation component as a whole is a two-in-one, three-in-one, or four-in-one composite film layer, or is bonded to the same bonding surface of the lens, or is fixed to the same position of the lens barrel. In other embodiments, the positions of the multiple optical films in the first polarization modulation component are not limited to the above. The first polarization modulation component 30a is taken as an example for description.

[0201] In some embodiments, the lens group includes two bonding surfaces. In the first polarization modulation component 30a, the first quarter wave plate 31 and the reflective polarization element 32 are respectively bonded to different bonding surfaces, and the different bonding surfaces can be selected from two of the second optical surface S2, the third optical surface S3, the fourth optical surface S4, the fifth optical surface S5 and the sixth optical surface S6.

[0202] In some other embodiments, in the first polarization modulation component 30a, the first quarter wave plate 31 and the reflective polarization element 32 are arranged at intervals and are respectively fixed on the lens barrel. The first quarter wave plate 31 and the reflective polarization element 32 may be both located between the second lens 12 and the third lens 13; or, the first quarter wave plate 31 and the reflective polarization element 32 are both located between the first lens 11 and the second lens 12; or, the first quarter wave plate 31 and the reflective polarization element 32 are both located on the side of the third lens 13 close to the image side; or, the first quarter wave plate 31 and the reflective polarization element 32 are respectively located at the following different positions: between the second lens 12 and the third lens 13, between the first lens 11 and the second lens 12, and on the side of the third lens 13 close to the image side.

[0203] In some other embodiments, in the first polarization modulation component 30a, one of the first quarter wave plate 31 and the reflective polarizing element 32 is fixed on the lens barrel, and the other one is attached to the attachment surface. For example, the first quarter wave plate 31 and the reflective polarizing element 32 are both located between the second lens 12 and the third lens 13, the first quarter wave plate 31 is attached to the fourth optical surface S4, and the reflective polarizing element 32 is fixed to the lens barrel; or, the first quarter wave plate 31 is fixed to the lens barrel, and the reflective polarizing element 32 is attached to the fifth optical surface S5. For another example, the first quarter wave plate 31 and the reflective polarizing element 32 are both located between the first lens 11 and the second lens 12, the first quarter wave plate 31 is attached to the second optical surface S2, and the reflective polarizing element 32 is fixed to the lens barrel; or, the first quarter wave plate 31 is fixed to the lens barrel, and the reflective polarizing element 32 is attached to the third optical surface S3. For another example, the first quarter wave plate 31 and the reflective polarizing element 32 are both located on a side of the third lens 13 close to the image side, the first quarter wave plate 31 is attached to the sixth optical surface S6, and the reflective polarizing element 32 is fixed on the lens barrel. For another example, the first quarter wave plate 31 and the reflective polarizing element 32 are respectively located at the following different positions: between the second lens 12 and the third lens 13, between the first lens 11 and the second lens 12, and on a side of the third lens 13 close to the image side.

[0204] Understandably, when the first polarization modulation component is composed of three optical films, the three optical films can also be separated. For example, the three optical films are separated into three independent optical films, each of which can be independently bonded to a bonding surface, or can be independently fixed to the lens barrel. Alternatively, the three optical films are separated into an independent optical film and a two-in-one composite film layer, and the independent optical film and the two-in-one composite film layer can be bonded to different bonding surfaces, or fixed to different positions of the lens barrel, or one is bonded to the bonding surface and the other is fixed to the lens barrel.

[0205] Specifically, in the first polarization modulation component 30b, the two-in-one composite film layer can be the first quarter wave plate 31 and the reflective polarization element 32, or the reflective polarization element 32 and the first linear polarizer 33. In the first polarization modulation component 30c, the two-in-one composite film layer can be the first quarter wave plate 31 and the reflective polarization element 32, or the first quarter wave plate 31 and the anti-reflection film 34.

[0206] Understandably, when the first polarization modulation component is composed of four optical films, the four optical films can also be separated. For example, the three optical films are separated into four independent optical films, each of which can be independently bonded to a bonding surface, or can be independently fixed to the lens barrel. Alternatively, the four optical films are separated into an independent optical film and a three-in-one composite film layer, the independent optical film and the three-in-one composite film layer can be bonded to different bonding surfaces, or fixed to different positions of the lens barrel, or one is bonded to the bonding surface and the other is fixed to the lens barrel. Alternatively, the four optical films are separated into two two-in-one composite film layers, the two two-in-one composite film layers can be bonded to different bonding surfaces, or fixed to different positions of the lens barrel, or one is bonded to the bonding surface and the other is fixed to the lens barrel.

[0207] Specifically, in the first polarization modulation component 30d, the three-in-one composite film layer can be the first linear polarizer 33, the reflective polarization element 32, and the first quarter wave plate 31, or can be the reflective polarization element 32, the first quarter wave plate 31, and the anti-reflection film 34. In the first polarization modulation component 30d, the two two-in-one composite film layers are respectively a stack of the first linear polarizer 33 and the reflective polarization element 32, and a stack of the first quarter wave plate 31 and the anti-reflection film 34.

[0208] Understandably, the situation where the multiple optical films in the first polarization modulation assembly are separated and bonded to different bonding surfaces can avoid the problem of overall waste of the composite film due to poor bonding of the composite film. The situation where the multiple optical films in the first polarization modulation assembly are bonded together on the same bonding surface is conducive to reducing the number of bonding times.

[0209] In the optical systems of the first to eleventh embodiments and their variations, in the second polarization modulation component 40, the second linear polarizer 41 and the second quarter wave plate 42 can be combined into a stack (or a two-in-one composite film layer) and fixed on the lens barrel or attached to the surface of the beam splitter 20 close to the object side; or, the second linear polarizer 41 and the second quarter wave plate 42 are fixed on the lens barrel respectively. In some other embodiments, the lens assembly includes the second quarter wave plate 42 but does not include the second linear polarizer 41, the second quarter wave plate 42 is fixed on the lens barrel, and the second linear polarizer 41 is attached to the display 110. In some other embodiments, the lens assembly does not include the second polarization modulation component 40, and the second polarization modulation component 40 is attached to the side of the outgoing image light of the display 110. In some other embodiments, the second linear polarizer 41 in the second polarization modulation component 40 of the lens assembly can be omitted, and the second quarter-wave plate 42 is fixed on the lens barrel, or attached to the surface of the splitter element 20 close to the object side, or attached to the side of the outgoing image light of the display 110.

[0210] It should be noted that, in order to solve the problems caused by the curved bonding process, although the number of bonding surfaces in the lens group can be greater than one, considering that the imaging quality of the optical system will be affected when the bonding surfaces increase, the number of bonding surfaces cannot be too much. That is, considering the imaging quality, the second polarization modulation component is either bonded to the display or fixed to the lens barrel, and it is best not to bond to the first lens.

[0211] The above description is made by taking the lens group consisting of three lenses as an example. In other embodiments, the number of lenses in the lens group may be greater than three. For example, the lens group may also consist of four lenses, or five lenses.

[0212] It can be understood that when the number of lenses in the lens group is greater than three, the splitter element is arranged on the object side of the lens closest to the object side, and the first polarization modulation component is attached to the object side of the lens closest to the image side. This can not only prevent the first polarization modulation component from being exposed to the outside, but also maximize the folding of the optical path.

[0213] It should be noted that with the development of silicon-based OLED displays, more and more display devices use silicon-based OLED displays. However, due to the high price of silicon-based OLED displays, the size of silicon-based OLED displays is usually relatively small, usually smaller than the diameter of the optical machine (i.e., the lens assembly mentioned above). If the display center of the display is aligned with the optical axis of the lens assembly, the final displayed field of view will be limited by the chief ray angle (CRA) of the display. Since the optical system of the display device is an ultra-short focus system, when the optical focal length is relatively large, the chief ray angle will be large, resulting in severe color deviation, which is usually not correctable by software.

[0214] In this regard, in order to improve the field of view of the display device, especially to improve the field of view of the display device using the silicon-based OLED display, in some embodiments of the present application, the display of the first optical system and / or the second optical system may have at least one of the horizontal offset, vertical offset and rotational offset compared to the optical axis of its lens assembly, so that in the first optical system and / or the second optical system, the display area is at least asymmetric about one of the first symmetry axis and the second symmetry axis of the lens assembly, so that when the above optical system is applied to the display device, part of the virtual image is imagined by the user through binocular stereoscopic vision, which is equivalent to enlarging the display content of the display in disguise; and since the inherent resolution of the two displays in the display device itself remains unchanged, it is equivalent to providing additional visible resolution and additional field of view, which is conducive to the improvement of angular resolution. In addition, in the embodiment of the present application, by enlarging the display content of the display in disguise, the color deviation problem caused by the large optical focal length of the optical system can also be avoided. Further, due to the offset of the two displays in the display device, the distance between the two displays is pulled apart, and the space between the two displays is larger, and this part of the space can be used to arrange other mechanisms (such as heat dissipation mechanisms or pupil distance adjustment mechanisms). The following combination Figure 1B , Figures 12 to 15 Specific instructions.

[0215] For the convenience of description below, the display of the first optical system and the display of the second optical system are referred to as the first display and the second display respectively, and the lens assembly of the first optical system and the lens assembly of the second optical system are referred to as the first lens assembly and the second lens assembly respectively.

[0216] Please refer again Figure 1B In the display device 1000a of the first embodiment of the present application, in the first optical system 100a, the first lens assembly 121 has a first symmetry axis A1 parallel to the first direction X and a second symmetry axis A2 parallel to the second direction Y, the intersection of the first symmetry axis A1 and the second symmetry axis A2 is the optical axis center O1 of the first lens assembly 121, and the display area AA of the first display 111 is symmetrical about the first symmetry axis A1 of the first lens assembly 121 and the second symmetry axis A2 of the first lens assembly 121, respectively.

[0217] Specifically, in the first optical system 100a, the display area AA of the first display 111 is rectangular and has a third symmetry axis A3 and a fourth symmetry axis A4 that are perpendicular to each other, and the intersection of the third symmetry axis A3 and the fourth symmetry axis A4 is the geometric center O2 of the display area AA of the first display 111. The third symmetry axis A3 of the first display 111 is parallel to the first direction X, the fourth symmetry axis A4 of the first display 111 is parallel to the second direction Y, and the geometric center O2 of the first display 111 coincides with the projection of the optical axis center O1 of the first lens assembly 121 in the third direction Z (or in other words, the geometric center O2 of the first display 111 is aligned with the optical axis of the first lens assembly 121 in the third direction Z).

[0218] The second optical system 200a has the same structure as the first optical system 100a, that is, the display area AA of the second display 112 is rectangular and symmetrical about the first symmetry axis A1 and the second symmetry axis A2 of the second lens assembly 122. The third symmetry axis A3 of the display area AA of the second display 112 is parallel to the first direction X, the fourth symmetry axis A4 of the second display 112 is parallel to the second direction Y, and the geometric center O2 of the second display 112 coincides with the projection of the optical axis center O1 of the second lens assembly 122 in the third direction Z (or in other words, the geometric center O2 of the second display 112 is aligned with the optical axis of the second lens assembly 122 in the third direction Z). In other embodiments, the display areas of the first display and the second display are not limited to rectangles, and may be circular or rounded rectangles, for example.

[0219] like Fig.12 Figure (b) and Figure 1B As shown in Figure (b), the difference between the display device 1000b of the second embodiment of the present application and the display device 1000a of the first embodiment is that: in the first optical system 100b of the display device 1000b, the display area AA of the first display 111 is symmetrical about the first symmetry axis A1 of the first lens assembly 121, and asymmetrical about the second symmetry axis A2 of the first lens assembly 121; in the second optical system 200b of the display device 1000b, the display area AA of the second display 112 is symmetrical about the first symmetry axis A1 of the second lens assembly 122, and asymmetrical about the second symmetry axis A2 of the second lens assembly 122.

[0220] Specifically, in the first optical system 100b corresponding to the left eye of the user, the geometric center O2 of the first display 111 has a first distance D1 offset to the left compared to the optical axis center O1 of the first lens assembly 121, and in the second optical system 200b corresponding to the right eye of the user, the geometric center O2 of the second display 112 has a second distance D2 offset to the right compared to the optical axis center O1 of the second lens assembly 122. In other words, in the first optical system 100b, the fourth symmetry axis A4 of the display area AA of the first display 111 can be obtained by translating the second symmetry axis A2 of the first lens assembly 121 along the negative direction of the first direction X by the first distance D1, and in the second optical system 200b, the fourth symmetry axis A4 of the display area AA of the second display 112 can be obtained by translating the second symmetry axis A2 of the second lens assembly 122 along the positive direction of the first direction X by the second distance D2.

[0221] The first distance D1 is in the range of (0, 0.5*W1), and the second distance D2 is in the range of (0, 0.5*W2), W1 is the size of the display area AA of the first display 111 in the first direction X, and W2 is the size of the display area AA of the second display 112 in the first direction X. When the first distance D1 is greater than or equal to 0.5*W1 and / or the second distance D2 is greater than or equal to 0.5*W2, the user's eyes will not be able to fuse to obtain an image. In some embodiments, W1 and W2 are equal, but not limited thereto.

[0222] After the image light of the display 110 of the first optical system 100b passes through the lens assembly 120 of the first optical system 100b, it forms a shape as shown in FIG. Fig.12 In the left visible range VAL shown in FIG. (a), the image light of the display 110 of the second optical system 200b passes through the lens assembly 120 of the second optical system 200b and forms a portion of the image on the user's right eye. Fig.12 The right visible range VAR shown in Figure (a) is superimposed with the left visible range VAL and the right visible range VAR to obtain the binocular visible range VA2.

[0223] Since in the first optical system 100b, the display area AA of the first display 111 is offset by a first distance D1 in the negative direction of the first direction X compared to the optical axis center O1 of the first lens assembly 121, Figure 1B The display device 1000a is equivalent to the left visible range VAL in the display device 1000b being shifted to the left by the first distance D1. Similarly, in the second optical system 200b, the display area AA of the second display 112 is shifted by the second distance D2 in the positive direction of the first direction X compared to the optical axis center O1 of the second lens assembly 122. Figure 1BThe display device 1000a is equivalent to the right visible range VAR in the display device 1000b being shifted right by the second distance D2. In this way, the binocular visible range VA2 of the display device 1000b is expanded by the sum of the first distance D1 and the second distance D2 in the first direction X, thereby improving the horizontal field of view and binocular visible range of the display device 1000b.

[0224] like Fig.13 Figure (b) and Figure 1B As shown in Figure (b), the difference between the display device 1000c of the third embodiment of the present application and the display device 1000a of the first embodiment is that: in the first optical system 100c of the display device 1000c, the display area AA of the first display 111 is asymmetric about the first symmetry axis A1 of the first lens assembly 121, and is symmetric about the second symmetry axis A2 of the first lens assembly 121; in the second optical system 200b of the display device 1000c, the display area AA of the second display 112 is asymmetric about the first symmetry axis A1 of the second lens assembly 122, and is symmetric about the second symmetry axis A2 of the second lens assembly 122.

[0225] Specifically, in the first optical system 100c corresponding to the user's left eye, the geometric center O2 of the display area AA of the first display 111 is offset upward by a third distance D3 compared to the optical axis center O1 of the first lens assembly 121, and in the second optical system 200c corresponding to the user's right eye, the geometric center O2 of the display area AA of the second display 112 is offset downward by a fourth distance D4 compared to the optical axis center O1 of the second lens assembly 122.

[0226] That is to say, in the first optical system 100c, the third symmetry axis A3 of the display area AA of the first display 111 can be obtained by translating the first symmetry axis A1 of the first lens assembly 121 by a third distance D3 in the positive direction of the second direction Y. In the second optical system 200c, the third symmetry axis A3 of the display area AA of the second display 112 can be obtained by translating the first symmetry axis A1 of the second lens assembly 122 by a fourth distance D4 in the negative direction of the second direction Y.

[0227] Specifically, the third distance D3 is in the range of (0, 0.5*L1), the fourth distance D4 is in the range of (0, 0.5*L2), L1 is the size of the display area AA of the first display 111 in the second direction Y, and L2 is the size of the display area AA of the second display 112 in the second direction Y. When the third distance D3 is greater than or equal to 0.5*L1 and the fourth distance D4 is greater than or equal to 0.5*L2, the user's eyes will not be able to fuse to obtain an image. In some embodiments, L1 is equal to L2, but is not limited thereto.

[0228] After the image light of the display 110 of the first optical system 100c passes through the lens assembly 120 of the first optical system 100c, it forms a light beam as shown in FIG. 1 on the left eye of the user. Fig.13 In the left visible range VAL shown in FIG. 1 (a), the image light of the display 110 of the second optical system 200c passes through the lens assembly 120 of the second optical system 200c and forms a portion of the image on the user's right eye. Fig.13 The right visible range VAR shown in Figure (a) is superimposed with the left visible range VAL and the right visible range VAR to obtain the binocular visible range VA3.

[0229] Since in the first optical system 100c, the display area AA of the first display 111 is offset by a third distance D3 in the positive direction of the second direction Y compared to the optical axis center O1 of the first lens assembly 121, Figure 1B The display device 1000a is equivalent to the left visible range VAL in the display device 1000c being shifted upward by a third distance D3 as a whole; similarly, since in the second optical system 200c, the display area AA of the second display 112 is shifted by a fourth distance D4 in the negative direction of the second direction Y compared to the optical axis center O1 of the second lens assembly 122, Figure 1B The display device 1000a is equivalent to the right visible range VAR in the display device 1000c being moved downward by the fourth distance D4. In this way, the binocular visible range VA2 of the display device 1000c is expanded by the sum of the third distance D3 and the fourth distance D4 in the second direction Y, thereby improving the vertical field of view and binocular visible range of the display device 1000c.

[0230] like Fig.14 Figure (b) and Figure 1B As shown in Figure (b), the difference between the display device 1000d of the fourth embodiment of the present application and the display device 1000a of the first embodiment is that: in the first optical system 100d of the display device 1000d, the display area AA of the first display 111 is asymmetric about the first symmetry axis A1 and the second symmetry axis A2 of the first lens assembly 121; in the second optical system 200d of the display device 1000d, the display area AA of the second display 112 is asymmetric about the first symmetry axis A1 and the second symmetry axis A2 of the second lens assembly 122.

[0231] Specifically, in the first optical system 100d corresponding to the user's left eye, the geometric center O2 of the first display 111 has an offset of a first distance D1 to the left compared to the optical axis center O1 of the first lens assembly 121, and an offset of a third distance D3 upward; in the second optical system 200d corresponding to the user's right eye, the geometric center O2 of the display area AA of the second display 112 has an offset of a second distance D2 to the right compared to the optical axis center O1 of the second lens assembly 122, and an offset of a fourth distance D4 downward.

[0232] That is to say, in the first optical system 100d, the fourth symmetry axis A4 of the display area AA of the first display 111 can be obtained by translating the second symmetry axis A2 of the first lens assembly 121 along the negative direction of the first direction X by a first distance D1, and the third symmetry axis A3 of the display area AA of the first display 111 can be obtained by translating the first symmetry axis A1 of the first lens assembly 121 along the positive direction Y by a third distance D3; in the second optical system 200d, the fourth symmetry axis A4 of the display area AA of the second display 112 can be obtained by translating the second symmetry axis A2 of the second lens assembly 122 along the positive direction X by a second distance D2, and the geometric center O2 of the display area AA of the second display 112 has an offset of a fourth distance D4 downward compared to the optical axis center O1 of the second lens assembly 122.

[0233] Specifically, the range of the first distance D1 is (0, 0.5W1), the range of the second distance D2 is (0, 0.5W2), the range of the third distance D3 is (0, 0.5*L1), and the range of the fourth distance D4 is (0, 0.5*L2). When the first distance D1 is greater than or equal to 0.5*W1 and / or the second distance D2 is greater than or equal to 0.5*W2 and / or the third distance D3 is greater than or equal to 0.5*L1 and / or the fourth distance D4 is greater than or equal to 0.5*L2, the user's eyes will not be able to fuse to obtain an image. In some embodiments, L1 is equal to L2, and W1 is equal to W2, but it is not limited thereto.

[0234] After the image light of the display 110 of the first optical system 100d passes through the lens assembly 120 of the first optical system 100d, a light beam as shown in FIG. 1 is formed on the left eye of the user. Fig.14 In the left visible range VAL shown in FIG. (a), the image light of the display 110 of the second optical system 200d passes through the lens assembly 120 of the second optical system 200d and forms a portion of the image on the user's right eye. Fig.14 The right visible range VAR shown in Figure (a) is superimposed with the left visible range VAL and the right visible range VAR to obtain the binocular visible range VA4.

[0235] Similarly, compared to Figure 1BThe display device 1000a shown in FIG. (b) is equivalent to the left visible range VAL in the display device 1000d being shifted to the left by a first distance D1 and upward by a third distance D3; similarly, compared with Figure 1B The display device 1000a is equivalent to the right visible range VAR in the display device 1000d being moved right by the second distance D2 and downward by the fourth distance D4. In this way, the binocular visible range VA2 of the display device 1000d is expanded by the sum of the first distance D1 and the second distance D2 in the first direction X, and the sum of the third distance D3 and the fourth distance D4 in the second direction Y, thereby improving the horizontal field of view, vertical field of view and binocular visible range of the display device 1000d.

[0236] like Fig.15 As shown in Figure (b), in the first optical system 100e of the display device 1000e, the display area AA of the first display 111 is asymmetric about the first symmetry axis A1 and the second symmetry axis A2 of the first lens assembly 121; in the second optical system 200e of the display device 1000e, the display area AA of the second display 112 is asymmetric about the first symmetry axis A1 and the second symmetry axis A2 of the second lens assembly 122.

[0237] Specifically, in the first optical system 100e corresponding to the user's left eye, the third symmetry axis A3 of the first display 111 can be obtained by rotating the first symmetry axis A1 of the first lens assembly 121 counterclockwise by a preset angle (i.e., the first angle θ1), and the fourth symmetry axis A4 of the first display 111 can be obtained by rotating the second symmetry axis A2 of the first lens assembly 121 counterclockwise by a preset angle (i.e., the first angle θ1); in the second optical system 200e corresponding to the user's right eye, the geometric center O2 of the display area AA of the second display 112 can be obtained by rotating the first symmetry axis A1 of the second lens assembly 122 clockwise by a preset angle (i.e., the second angle θ2), and the fourth symmetry axis A4 of the second display 112 can be obtained by rotating the second symmetry axis A2 of the second lens assembly 122 clockwise by a preset angle (i.e., the second angle θ2).

[0238] The value range of the first angle θ1 is (-90°, 0), that is, in the first optical system 100e, the third symmetry axis A3 is in the counterclockwise direction of the first symmetry axis A1, and the rotation angle is not greater than 90°. The value range of the second angle θ2 is (0, 90°), that is, in the second optical system 200e, the third symmetry axis A3 is in the clockwise direction of the first symmetry axis A1, and the rotation angle is not greater than 90°. When the value of the first angle θ1 exceeds (-90°, 0), and / or the value of the second angle θ2 exceeds (0, 90°), the user's eyes will not be able to fuse to obtain an image. In some embodiments, the absolute value of the first angle θ1 is equal to the absolute value of the second angle θ2, but is not limited thereto.

[0239] After the image light of the display 110 of the first optical system 100e passes through the lens assembly 120 of the first optical system 100e, a light beam as shown in FIG. 1 is formed on the left eye of the user. Fig.15 In the left visible range VAL shown in FIG. 1 (a), the image light of the display 110 of the second optical system 200e passes through the lens assembly 120 of the second optical system 200e and forms a portion of the image on the user's right eye. Fig.15 The right visible range VAR shown in Figure (a) is superimposed with the left visible range VAL and the right visible range VAR to obtain the binocular visible range VA5.

[0240] Since the display area AA of the first display 111 in the first optical system 100e is rotated counterclockwise around the geometric center O2 by the first angle θ1, compared with Figure 1B The display device 1000a shown in (b) of FIG. 1 is equivalent to the left visible range VAL in the display device 1000e being rotated to the left by the first angle θ1 as a whole; similarly, since in the second optical system 200e, the display area AA of the second display 112 is rotated clockwise around the geometric center O2 by the second angle θ2 as a whole, compared with Figure 1B The display device 1000a is equivalent to the right visible range VAR in the display device 1000e being rotated right by a second angle θ2. In this way, the diagonal field of view and the binocular visible range of the display device 1000e are improved.

[0241] In other embodiments, in the display device, the first display may have a horizontal offset and a rotational offset compared to the optical axis of the first lens assembly, or may have a vertical offset and a rotational offset, or may have a horizontal offset, a vertical offset, and a rotational offset. Similarly, the second display may have a horizontal offset and a rotational offset compared to the optical axis of the second lens assembly, or may have a vertical offset and a rotational offset, or may have a horizontal offset, a vertical offset, and a rotational offset.

[0242] That is to say, in the display device, the third symmetry axis of the display area of ​​the first display can be obtained by rotating the first symmetry axis of the first lens assembly (such as counterclockwise rotation), translating in the vertical direction (such as upward translation, or downward translation), or simultaneous rotation (such as counterclockwise rotation) and translation in the vertical direction (such as upward translation, or downward translation); the third symmetry axis of the display area of ​​the second display can be obtained by rotating the first symmetry axis of the second lens assembly (such as clockwise rotation), translating in the vertical direction (such as downward translation, or upward translation), or simultaneous rotation (such as clockwise rotation) and translation in the vertical direction (such as downward translation, or upward translation), and if both the first display and the second display are translated in the vertical direction, the translation directions of the two are opposite.

[0243] In addition, to ensure that the user's two eyes can fuse a complete image, in the horizontal direction, the translation distance of the first display and the second display does not exceed half of the size of their display areas in the horizontal direction; in the vertical direction, the translation distance of the first display and the second display does not exceed half of the size of their display areas in the vertical direction.

[0244] It should be noted that the above-mentioned display device can also be used in the medical field. Specifically, the display device can be used in a virtual endoscopy (VE) system to simulate the effects of various endoscopic examinations, thereby overcoming the disadvantage that traditional optical endoscopes need to be inserted into the human body, and as a non-invasive contact examination method, provide doctors with a basis for diagnosis or be used in preoperative simulation of surgery and training of medical staff.

[0245] In the display device of one embodiment of the present application, the displays of the first optical system and the second optical system are both OLED displays. The display in the first optical system is translated to the left by 10% of its display area compared to its lens assembly, and the display in the second optical system is translated to the right by 10% of its display area compared to its lens assembly, so as to provide additional resolution for the display device, which is beneficial to improve the angular resolution and horizontal field of view of the display device. The second polarization modulation component includes a second linear polarizer and a second quarter wave plate. The second linear polarizer and the second quarter wave plate are bonded together to form a two-in-one composite film layer, and the side where the second linear polarizer is located is bonded to the display.

[0246] The lens assembly in the first optical system is the same as the lens assembly in the second optical system, and both include a lens group 10, a beam splitter 20, and a first polarization modulation component 30d. The beam splitter 20 is a 5 / 5 beam splitter film evaporated on the first optical surface S1.

[0247] Specifically, the first optical surface S1 and the second optical surface S2 of the first lens 11 are both even-order aspheric surfaces, and the third optical surface S3 and the fourth optical surface S4 of the second lens 12 are both even-order aspheric surfaces, and their surface equations are the above formula 2. The structural parameters are shown in Tables 1 and 2.

[0248] Table 1

[0249] Face number 1 / c k r(mm) S1 -70.98003 4.717462 25.22645 S2 -197.9267 0 25.22645 S3 -47.75228 -6.1431 24.20879 S4 -129.5794 0 24.20879

[0250] Table 2

[0251] Face number <![CDATA[α1]]> <![CDATA[α2]]> <![CDATA[α3]]> <![CDATA[α4]]> <![CDATA[α5]]> <![CDATA[α6]]> <![CDATA[α7]]> <![CDATA[α8]]> S1 0 -4.357E-07 2.169E-09 1.959E-13 1.999E-15 -4.066E-18 -5.172E-21 0 S2 0 -5.158E-06 2.033E-09 2.429E-12 -1.466E-16 1.711E-18 3.139E-22 0 S3 0 2.736E-06 4.326E-09 -3.132E-12 -2.759E-15 -8.889E-19 -6.745E-22 0 S4 0 1.495E-05 -1.391E-09 -1.202E-12 -1.768E-15 -2.700E-17 5.108E-22 0

[0252] The fifth optical surface S5 is a bonding surface, and its surface equation is the above-mentioned formula 1. Its structural parameters are shown in Table 3 below.

[0253] Table 3

[0254] Face number Ry(mm) Rx(mm) ky kx r(mm) S5 3.68E+03 0 0 0 22.630919

[0255] The sixth optical surface S6 is a free-form surface, and its surface equation is the above formula 3. Its structural parameters are shown in Table 4 below.

[0256] Table 4

[0257]

[0258]

[0259] like Fig.16 As shown, the horizontal axis is the spatial frequency, the unit is line pair / millimeter (lp / mm), and the vertical axis is the modulus of the optical transfer function (OTF). At a spatial frequency of 76lp / mm and a wavelength of 550nm, the modulation transfer function (MTF) value is greater than 0.7, with high resolution and contrast.

[0260] like Fig.17 As shown, the maximum grid distortion is -27.5756% and the SMIA TV distortion is -13.9502%.

[0261] The above implementation modes are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred implementation modes, a person skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A lens assembly, characterized in that: include: A plurality of lenses arranged in sequence from the object side to the image side, each of the lenses comprising an object side surface and an image side surface that are arranged opposite to each other, the object side surface of each lens faces the object side, and the image side surface of each lens faces the image side; A beam splitter, a first quarter wave plate, and a reflective polarization element are arranged in sequence from the object side to the image side; and A lens barrel, wherein the plurality of lenses, the beam splitter, the first quarter wave plate and the reflective polarization element are all located in the lens barrel and on an optical path between the object side and the image side; Wherein, at least one of the first quarter wave plate and the reflective polarization element is fixed on the lens barrel independently of the multiple lenses; or, the object side surface and the image side surface of the multiple lenses include at least one bonding surface, and at least one of the first quarter wave plate and the reflective polarization element is bonded to the bonding surface, and the bonding surface is a quadratic surface with zero curvature in at least one direction.

2. The lens assembly according to claim 1, characterized in that The surface equation of the quadratic surface with zero curvature in at least one direction is: In the surface equation of the quadratic surface with zero curvature in at least one direction, Rx is the curvature radius of the bonding surface in the first direction, Ry is the curvature radius of the bonding surface in the second direction, Z1 is the sagittal height of the bonding surface in the third direction, the first direction, the second direction and the third direction are perpendicular to each other, k x and k y is the cone coefficient, and at least one of Rx and Ry is infinite.

3. The lens assembly according to claim 1 or 2, characterized in that: The object-side surfaces and the image-side surfaces of the plurality of lenses further include at least one of a free-form surface, a spherical surface, a rotationally symmetric aspherical surface, and a Fresnel surface.

4. The lens assembly according to claim 3, characterized in that The free-form surface includes at least one of an extended polynomial surface, a Zernike polynomial surface and a Q-type polynomial surface.

5. The lens assembly according to claim 3 or 4, characterized in that: The object-side surfaces and the image-side surfaces of the plurality of lenses include the rotationally symmetric aspherical surfaces, and the surface equation of the rotationally symmetric aspherical surfaces is: In the surface equation of the rotationally symmetric aspheric surface, Z2 is the vector height of the rotationally symmetric aspheric surface, c is the curvature of the rotationally symmetric aspheric surface, k is the quadratic surface coefficient of the rotationally symmetric aspheric surface, r is the semi-aperture of the lens to which the rotationally symmetric aspheric surface belongs, α1, α2, α3, α4, α5, α6, α7, and α8 are the coefficients of the second-order term, fourth-order term, sixth-order term, tenth-order term, twelfth-order term, fourteenth-order term, and sixteenth-order term, respectively.

6. The lens assembly according to any one of claims 1 to 5, characterized in that: The first quarter wave plate and the reflective polarizing element are combined into a stack and adhered to the bonding surface; or, the first quarter wave plate and the reflective polarizing element are combined into a stack and fixed on the lens barrel; or, the first quarter wave plate and the reflective polarizing element are respectively adhered to different bonding surfaces; or, the first quarter wave plate and the reflective polarizing element are arranged at intervals and are respectively fixed to the lens barrel; or, one of the first quarter wave plate and the reflective polarizing element is fixed on the lens barrel, and the other one is adhered to the bonding surface.

7. The lens assembly according to any one of claims 1 to 6, characterized in that: The plurality of lenses include a first lens, a second lens, and a third lens arranged in sequence from the object side to the image side. The beam splitter is located on the object side of the first lens, and the object side of the third lens is the bonding surface.

8. The lens assembly according to claim 7, wherein: The reflective polarizing element and the first quarter wave plate are combined into a stack and attached to the object side surface of the third lens.

9. The lens assembly according to claim 7, wherein: The lens assembly further includes a first linear polarizer, which is attached to the surface of the reflective polarizing element close to the image side. The first linear polarizer, the reflective polarizing element and the first quarter wave plate are combined into a stack and attached to the object side of the third lens.

10. The lens assembly according to claim 7, wherein: The lens assembly further includes an anti-reflection film, which is adhered to the surface of the first quarter wave plate close to the object side. The reflective polarizing element, the first quarter wave plate and the anti-reflection film are combined into a stack and adhered to the object side surface of the third lens.

11. The lens assembly according to claim 7, wherein: The lens assembly also includes an anti-reflection film and a first linear polarizer, the anti-reflection film is adhered to the surface of the first quarter-wave plate close to the object side, the first linear polarizer is adhered to the surface of the reflective polarizing element close to the image side, the first linear polarizer, the reflective polarizing element, the first quarter-wave plate and the anti-reflection film are combined into a stack and adhered to the object side surface of the third lens.

12. The lens assembly according to any one of claims 1 to 11, characterized in that The center thickness of each of the lenses ranges from 0.8 mm to 12 mm, and the edge thickness of each of the lenses ranges from 0.8 mm to 12 mm.

13. The lens assembly according to any one of claims 1 to 12, characterized in that The multiple lenses include convex lenses and / or concave lenses; when the multiple lenses include convex lenses, the ratio of the center thickness to the edge thickness of the convex lenses is less than 7:1; when the multiple lenses include concave lenses, the ratio of the center thickness to the edge thickness of the concave lenses is greater than 1:

7.

14. The lens assembly according to any one of claims 1 to 13, characterized in that The lens assembly further includes a second quarter wave plate located on a side of the beam splitting element close to the object side.

15. The lens assembly of claim 14, wherein: The lens assembly further includes a second linear polarizing plate located on a side of the second quarter wave plate away from the beam splitting element.

16. An optical system, characterized in that: include: The lens assembly according to any one of claims 1 to 15; as well as A display is located on the object side of the lens assembly, and the display is used to emit image light toward the lens assembly.

17. The optical system according to claim 16, wherein: The lens assembly has a first symmetry axis and a second symmetry axis which are perpendicular to each other, and the intersection of the first symmetry axis and the second symmetry axis is the optical axis center of the lens assembly; the display area of ​​the display is asymmetric about at least one of the first symmetry axis and the second symmetry axis.

18. The optical system according to claim 17, wherein: The display area has a third symmetry axis and a fourth symmetry axis that are perpendicular to each other; the third symmetry axis can be obtained by rotating the first symmetry axis by a preset angle and / or translating a first distance in a direction parallel to the second symmetry axis, and the range of the preset angle is (-90°, 90°). When the third symmetry axis is in the counterclockwise direction of the first symmetry axis, the value of the preset angle is negative, and when the third symmetry axis is in the clockwise direction of the first symmetry axis, the value of the preset angle is positive. The range of the first distance is [0, 0.5*L), where L is the size of the display area in a direction parallel to the second symmetry axis; the fourth symmetry axis can be obtained by rotating the second symmetry axis by the preset angle and / or translating a second distance in a direction parallel to the first symmetry axis, and the range of the second distance is [0, 0.5*W), where W is the size of the display area in a direction parallel to the first symmetry axis.

19. A display device, characterized in that: include: case; as well as a first optical system and a second optical system mounted on the housing; Wherein, the first optical system and the second optical system are the optical systems as described in any one of claims 16 to 18.

20. The display device according to claim 19, characterized in that When a user wears the display device, the first optical system corresponds to the left eye of the user, and the second optical system corresponds to the right eye of the user, and the display area of ​​the first optical system and the display area of ​​the second optical system both have the third symmetry axis and the fourth symmetry axis; In the first optical system, the third symmetry axis can be obtained by rotating the first symmetry axis counterclockwise and / or translating in a direction from the bridge of the user's nose to the forehead of the user, and the fourth symmetry axis can be obtained by rotating the second symmetry axis counterclockwise and / or translating in a direction from the right eye of the user to the left eye of the user; In the second optical system, the third symmetry axis can be obtained by rotating the first symmetry axis clockwise and / or translating in a direction from the user's forehead to the user's nose bridge, and the fourth symmetry axis can be obtained by rotating the second symmetry axis clockwise and / or translating in a direction from the user's left eye to the user's right eye.

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