VR optical system and near-eye display device

Abstract

The application discloses a VR optical system and a near-eye display device, the VR optical system comprising an optical lens close to an eye side and at least one microlens array close to a display side; the optical lens has positive focal power, the optical lens has a first surface close to the eye side and a second surface away from the eye side, at least one of the first surface and the second surface is aspherical, and the first surface is convex; the microlens array has a plurality of microlens units, and the plurality of microlens units have the same or different focal lengths; wherein the VR optical system satisfies a condition formula: 1.5 < TTL / (f*tanθ) < 3, TTL represents the total optical length of the VR optical system, f represents the effective focal length of the VR optical system, and theta represents the maximum half field angle of the VR optical system. By setting the optical lens and the microlens array, multiple fields of view can be established, the field of view in each small range is optimized, and therefore clearer imaging quality can be obtained, and the resolving power of the VR system is improved.

Description

Technical Field

[0001] This invention belongs to the field of display technology, and particularly relates to a VR optical system and a near-eye display device. Background Technology

[0002] With the development of virtual reality (VR) technology, the forms and types of VR devices are becoming increasingly diverse, and their application areas are becoming more and more extensive, such as near-eye displays and head-mounted displays. Among them, head-mounted displays use optical technology to transmit the image light emitted by the display to the user's pupils, realizing virtual and magnified images within the user's near-eye range, providing users with intuitive and visual image and video information. The near-eye optical system is the core of the head-mounted display device, enabling the function of displaying the image on the display in front of the user's eyes to form a virtual magnified image.

[0003] To provide users with an excellent sensory experience, near-eye optical systems typically need to have a small overall length, a large field of view, and high-quality imaging. Currently, near-eye optical systems on the market are evolving from single-lens structures to multi-lens combinations or Fresnel lens arrays. A Fresnel lens array can essentially be viewed as an array of microlenses, each of which can focus light while saving significant amounts of material. While Fresnel lenses reduce lens thickness, they suffer from lower image quality. Furthermore, the uniform curvature of each microlens in the array leads to severe astigmatism when different fields of view pass through microlenses with the same curvature. This is especially problematic as the field of view increases, as the microlens array cannot eliminate large-angle aberrations, resulting in blurred edges and low overall system resolution. Therefore, reducing the size of near-eye optical systems while improving the field of view and imaging quality is a key focus for those in the field.

[0004] The content of the background section is merely the technology known to the inventor and does not necessarily represent the prior art in this field. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a VR optical system and a near-eye display device, which have at least the characteristics of small overall length, large field of view, and high resolution.

[0006] The embodiments of the present invention achieve the above-mentioned objectives through the following technical solutions.

[0007] On one hand, the present invention provides a VR optical system, including an optical lens near the human eye and at least one microlens array near the display side;

[0008] The optical lens has a positive optical power. The optical lens has a first surface close to the human eye side and a second surface away from the human eye side. At least one of the first surface and the second surface is an aspherical surface, and the first surface is a convex surface;

[0009] The microlens array has a first surface and a second surface arranged opposite to each other; the microlens array has a plurality of microlens units, and the plurality of microlens units have the same or different focal lengths;

[0010] Among them, the VR optical system satisfies the conditional formula: 1.5 < TTL / (f×tanθ) < 3, where TTL represents the total optical length of the VR optical system, f represents the effective focal length of the VR optical system, and θ represents the maximum half field angle of the VR optical system.

[0011] On the other hand, the present invention also provides a near-eye display device, including: a display element, the VR optical system as described above; wherein the display element is used to emit an optical signal, and the optical signal includes image information; the VR optical system is arranged in the light-emitting direction of the display element, and the second microlens array is closer to the light-emitting surface of the display element than the optical lens; the VR optical system is used to modulate the optical signal emitted by the display element so that the human eye can receive the modulated image information.

[0012] Based on the above, the VR optical system and the near-eye display device provided by the present invention, by arranging an optical lens close to the human eye side and at least one microlens array close to the display side, especially each microlens unit in the microlens array has the same or different focal lengths, can establish multiple fields of view and optimize the field of view in each small range, so as to obtain a clearer imaging quality and improve the resolution of the VR system; at the same time, due to the reasonable combination of the optical lens and the microlens array, not only can the overall thickness of the VR optical system be effectively reduced, but also the imaging quality of the system at different viewing angles can be effectively improved, enabling the carried near-eye display device to have a larger field of view angle, a more compact structure and clearer resolution in the entire field of view, effectively enhancing the user's visual experience. Description of the Drawings

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0014] Figure 1 It is a schematic cross-sectional structure diagram of the microlens array provided in the embodiment of the present invention;

[0015] Figure 2 This is a schematic diagram of the structure of the VR optical system provided in the first embodiment of the present invention;

[0016] Figure 3 This is an MTF curve diagram of the VR optical system provided in the first embodiment of the present invention;

[0017] Figure 4 This is a schematic diagram of the structure of the VR optical system provided in the second embodiment of the present invention;

[0018] Figure 5 This is an MTF curve diagram of the VR optical system provided in the second embodiment of the present invention;

[0019] Figure 6 This is a schematic diagram of the structure of the VR optical system provided in the third embodiment of the present invention;

[0020] Figure 7 This is an MTF curve diagram of the VR optical system provided in the third embodiment of the present invention;

[0021] Figure 8 This is a schematic diagram of the structure of the VR optical system provided in the fourth embodiment of the present invention;

[0022] Figure 9 This is an MTF curve diagram of the VR optical system provided in the fourth embodiment of the present invention;

[0023] Figure 10 This is a schematic diagram of the structure of the VR optical system provided in the fifth embodiment of the present invention;

[0024] Figure 11 This is an MTF curve diagram of the VR optical system provided in the fifth embodiment of the present invention;

[0025] Figure 12 This is a schematic diagram of the structure of the VR optical system provided in the sixth embodiment of the present invention;

[0026] Figure 13 This is an MTF curve diagram of the VR optical system provided in the sixth embodiment of the present invention;

[0027] Figure 14 This is a schematic diagram of the near-eye display device provided in the seventh embodiment of the present invention. Detailed Implementation

[0028] To make the objectives, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be thorough and complete.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Throughout this specification, the same reference numerals refer to the same elements.

[0030] In this article, "near the optical axis" refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the near-optical axis region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the near-optical axis region.

[0031] This invention provides a VR optical system, including an optical lens near the human eye and at least one microlens array near the display side; specifically, to better balance the aberrations of the system, at least one microlens array in the VR optical system includes a first microlens array near the optical lens and a second microlens array near the display side.

[0032] The focal lengths of the microlens units in the first microlens array and the microlens units in the second microlens array can be the same or different. Microlens units at different positions use different focal lengths, which, in conjunction with optical lenses, can establish multiple fields of view and optimize the field of view within each small range, thereby obtaining clearer imaging quality and improving the resolution of the VR system.

[0033] Specifically, the focal length of the microlens unit on the first microlens array is positive, and the focal length of the microlens unit on the second microlens array is positive; or the focal length of the microlens unit on the first microlens array is positive, and the focal length of the microlens unit on the second microlens array is negative; the first and second microlens arrays use different focal length combinations, both of which enable the VR optical system to have clear resolution throughout the entire field of view.

[0034] The thickness of the first microlens array and the width perpendicular to the optical axis direction are equal in both the first microlens array and the second microlens array.

[0035] The effective aperture of the optical lens is smaller than the width of the first microlens array or the second microlens array in the direction perpendicular to the optical axis.

[0036] A glass substrate or an air gap is provided between the first microlens array and the second microlens array.

[0037] To facilitate understanding of the structure of the microlens array in the embodiments of the present invention, please refer to [link / reference needed]. Figure 1 The diagram shows a schematic of the structure of a microlens array 40 provided in an embodiment of the present invention. The first and second microlens arrays have the same or similar structures. The microlens array 40 has a first surface 41 and a second surface 42 arranged opposite to each other. The first surface 41 of the microlens array faces the human eye, and the second surface 42 faces the display side (the display element side). In some embodiments, the second surface 42 can be a plane. The microlens array 40 is composed of multiple microlens units 401, which can be arranged in a matrix or other array configurations, depending on actual requirements. Each microlens unit 401 has a first optical surface and a second optical surface. The first optical surface of each microlens unit 401 forms the first surface 41 of the microlens array, and the second optical surface of each microlens unit 401 forms the second surface 42 of the microlens array. The focal length of each microlens unit 401 can be the same or different. When the focal length of each microlens unit 401 is the same, the curvature of the microlens units at each position is equal. When the focal lengths of the microlens units 401 are different, for example, among multiple microlens units 401 on a horizontal or vertical line passing through the microlens unit 401 located at the center of the microlens array 40, the change in focal length can be a gradual change from the central microlens unit towards the left and right sides or the top and bottom sides. In some embodiments, the change in focal length can be a gradual increase from the center towards the left and right sides or the top and bottom sides, or the change in focal length can be a gradual decrease from the center towards the left and right sides or the top and bottom sides, depending on the specific requirements. When the microlens units 401 have different focal lengths, multiple fields of view can be established, and the field of view within each small range can be optimized, thereby obtaining a clearer imaging quality.

[0038] The optical lens has positive optical power and has a first surface near the human eye and a second surface away from the human eye. At least one of the first surface and the second surface is aspherical. The first surface is convex, and the second surface can be convex or concave, but this invention is not limited thereto.

[0039] As one implementation, when some surfaces of the lens or microlens unit in an optical lens are aspherical, each aspherical surface shape satisfies the following equation:

[0040]

[0041] Where z is the distance vector from the vertex of the aspherical surface at a height of h along the optical axis, c is the paraxial curvature of the surface, k is the quadratic surface coefficient con ic, and A 2i is the aspherical surface shape coefficient of the 2ith order.

[0042] In some embodiments, the VR optical system satisfies the following condition:

[0043] 1.5 <TTL / (f×tanθ)<3; (1)

[0044] Where TTL represents the total optical length of the VR optical system, f represents the effective focal length of the VR optical system, and θ represents the maximum half-field angle of the VR optical system. Satisfying the above condition (1) is beneficial for the VR system to obtain a smaller optical length while achieving a larger field of view, which can better meet the development direction of near-eye display devices.

[0045] In some embodiments, the VR optical system satisfies the following condition:

[0046] f1 / f>2; (2)

[0047] Where f1 represents the focal length of the optical lens, and f represents the effective focal length of the VR optical system. The focal length of the system is inversely proportional to the size of the viewing angle. The entire VR optical system is constructed by combining conventional optical lenses and microlens arrays for imaging. In the VR system, the focal length f1 of the optical lens is relatively stable, satisfying the above condition (2), so that the focal length f of the VR optical system is controlled within a certain range, ensuring that the system obtains a sufficiently large field of view and a strong sense of perspective. At the same time, it can also effectively control the system's manufacturing cost.

[0048] In some embodiments, the VR optical system satisfies the following condition:

[0049] -0.01 <R1 / R2<0.5;(3)

[0050] Wherein, R1 represents the radius of curvature of the first surface of the optical lens, and R2 represents the radius of curvature of the second surface of the optical lens. Satisfying the above condition (3) makes the first surface of the optical lens have better light-gathering ability, and the second surface has a larger radius of curvature relative to the first surface. Even though the second surface has some optical performance gains, it also makes the surface shape of the second surface have a gentler trend, which meets the more stringent processing requirements.

[0051] In some embodiments, the VR optical system satisfies the following condition:

[0052] 1.2 <CT1 / CT23<2.0;(4)

[0053] Wherein, CT1 represents the thickness of the optical lens on the optical axis, and CT23 represents the thickness on the optical axis from the first surface of the first microlens array to the second surface of the second microlens array. Satisfying the above condition (4) is beneficial to controlling the total length of the entire VR optical system and realizing the miniaturization of the system; moreover, the overall thickness CT23 between the microlens arrays is less than the thickness CT1 of the optical lens, which will also give the entire microlens array better refractive power, thereby giving the entire optical system a larger field of view and improving the field of view of the near-eye display device.

[0054] This invention also provides a near-eye display device, including a display element and the aforementioned VR optical system; wherein the display element is used to emit light signals, the light signals including image information. The VR optical system is disposed in the light-emitting direction of the display element, wherein the second microlens array is closer to the light-emitting surface of the display element than the optical lens; the VR optical system is used to modulate the light signals emitted by the display element so that the modulated image information can be received by the human eye. The light propagation path in the near-eye display device is as follows: the light signal (image information) emitted by the display element is transmitted to the optical lens via the microlens array, the light signal is collected by the optical lens and transmitted to the human eye (human eye side), and the human eye can form a virtual, magnified image at a distance (a considerable distance in front of the pupil). Therefore, the user wearing the near-eye display device can see intuitively visible images and video information.

[0055] In some embodiments, the distance from the display element to the second surface of the second microlens array on the optical axis is less than the effective focal length of the VR optical system, which helps the system provide better resolution.

[0056] In some embodiments, the display element may be a flat panel display. In some embodiments, the display element may also be a curved display. Since the human eyeball is convex and curved, the curvature of the curved screen can ensure that the distance of the emitted light to the human eye is equal, thereby providing a better sensory experience.

[0057] The VR optical system and near-eye display device provided by the present invention employ an optical lens, at least one microlens array and a display element, which can greatly reduce the total length of the near-eye optical system, and at the same time enable the optical system to obtain better resolution at a large field of view.

[0058] The embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0059] First Embodiment

[0060] Figure 2This is a schematic diagram of the structure of the VR optical system 100 provided in the first embodiment of the present invention. The VR optical system 100 includes an optical lens L1, a first microlens array L2, and a second microlens array L3 sequentially from the human eye side S0 to the display side S9. A substrate G1 is disposed between the first microlens array L2 and the second microlens array L3. The substrate G1 is a glass substrate and the glass substrate does not have optical power.

[0061] The optical lens L1 has positive power and a focal length of 28.84 mm. The optical lens L1 has a first surface S1 close to the human eye and a second surface S2 away from the human eye. The first surface S1 is convex and the second surface S2 is concave near the optical axis. Both the first surface S1 and the second surface S2 are aspherical. Using aspherical lenses is beneficial to controlling the direction of light refraction, thereby increasing the viewing angle entering the human eye and obtaining a sufficient sense of immersion.

[0062] A microlens array (MLA) is an array composed of several microlens units with apertures and relief depths at the micrometer level, arranged in a specific configuration. By adjusting the shape, focal length, arrangement, and duty cycle of the microlens units within the MLA, certain optical functions can be achieved, improving the integration and performance of the optical system. In this embodiment, like traditional lenses, the smallest functional unit—the microlens unit—can be a spherical mirror, aspherical mirror, cylindrical mirror, prism, etc., and can achieve focusing, imaging, and beam transformation functions at micro-optical angles. Moreover, due to the small size and high integration of the microlens units, it can form many novel optical systems, accomplishing functions that traditional optical elements cannot. The structure of a microlens array can be categorized by the arrangement of its smallest functional units, such as single-row, M*N, and full-area arrangements. It can also be classified as single-sided or double-sided arrays. Full-area arrangements can be infinitely expanded without clear boundaries, allowing for flexible setting of different sizes to meet product functional requirements. For example... Figure 1 The figure shows a two-dimensional planar schematic diagram of a microlens array arranged in a full-area pattern. The microlens array has multiple microlens units in both the X-axis and Y-axis directions. The number of microlens units in the X-axis and Y-axis and the width of the microlens array are set according to the imaging requirements.

[0063] Specifically, in the embodiments of the present invention, the first microlens array L2 and the second microlens array L3 are both single-sided arrays. Specifically, the first surface S3 of the first microlens array L2 and the first surface S7 of the second microlens array L3 are each composed of multiple microlens units. In order to better achieve the convergence of incident light rays at each field of view, the first microlens array L2 and the second microlens array L3 in this embodiment have 10 microlens units on the X-axis and Y-axis respectively, that is, a 10*10 microlens array, and the width on the X-axis and Y-axis is 8mm. The 5*5 microlens units located in the middle position participate in optical imaging. The optical axis of the VR optical system passes through the center O of the microlens unit in the middle position of the first microlens array L2 and the second microlens array L3. This setting can reduce the color bleeding phenomenon that occurs when stitching images due to the edges between too many microlens units, and also reduces the manufacturing difficulty to a certain extent.

[0064] The radii of curvature of each microlens unit on the first microlens array L2 and the second microlens array L3 can be the same or different. Specifically, in this embodiment, the focal length of each microlens unit in the first microlens array L2 and the second microlens array L3 is the same, and the focal length is 10.32 mm. The microlens units on the first surface S3 of the first microlens array L2 and the first surface S7 of the second microlens array L3 are both convex surfaces, and each microlens unit is a spherical surface. The second surface S4 of the first microlens array L2 and the second surface S8 of the second microlens array L3 are both planar surfaces with infinite radii of curvature.

[0065] In VR optical systems, the widths of the first and second microlens arrays L2 and L3 along the X-axis or Y-axis are significantly larger than the effective aperture of the optical lens L1. This allows for a more significant refraction of light incident on the microlens arrays, thus meeting the emission surface size requirements of the associated display elements. The optical lens L1 can be made of resin or glass, while the microlens arrays can be made of glass. Both the optical lens L1 and the microlens arrays can be made of high-refractive-index materials, enabling the VR optical system to be made thinner. While maintaining the optical performance of the VR system, this reduces the thickness and weight of the module, providing a greater advantage in market applications.

[0066] Specifically, the parameters of the VR optical system 100 in this embodiment are shown in Table 1 below, where the spacing is the distance between two adjacent surfaces on the optical axis.

[0067] Table 1

[0068]

[0069]

[0070] In this embodiment, the first surface S1 and the second surface S2 of the optical lens L1 are both aspherical surfaces, and the surface shape coefficients of each aspherical surface are shown in Table 2 below.

[0071] Table 2

[0072] Face number k <![CDATA[A4]]> <![CDATA[A6]]> <![CDATA[A8]]> <![CDATA[A 10 ]]> S1 -11.466 3.012E-003 -2.095E-005 -2.340E-008 -6.145E-011 S2 -31.577 6.015E-003 -7.794E-006 -1.277E-007 -7.741E-011

[0073] Based on the settings in Tables 1 and 2, the VR optical system 100 has an ultra-large field of view of 90° per eye. It employs a conventional optical lens plus two microlens arrays, which not only significantly reduces the overall thickness of the VR optical system and reduces the total optical length (TTL, the distance from the first surface of the optical lens L1 to the display side on the optical axis) to 12.835 mm, but also greatly improves the imaging quality in each field of view. Figure 3 The MTF curve of the VR optical system 100 provided by this invention is shown. As can be seen from the MTF performance graph, the MTF value of the VR optical system 100 at the center field of view across the entire frequency range of 14 l p / mm is greater than 20%, meeting the imaging requirements of the human eye. Therefore, the VR optical system 100 provided by this invention, when applied, can have a larger field of view, a more compact structure, and clearer resolution throughout the entire field of view, effectively improving the user's visual experience.

[0074] Second Embodiment

[0075] Figure 4 This is a schematic diagram of the structure of the VR optical system 200 provided in the second embodiment of the present invention. The VR optical system 200 includes an optical lens L1, a first microlens array L2, and a second microlens array L3 sequentially from the human eye side S0 to the display side S7. The first microlens array L2 and the second microlens array L3 are not separated by a glass substrate, but by an air gap. The use of air as the substrate between the two microlens arrays helps to reduce the weight of the VR system.

[0076] The VR optical system 200 in this embodiment has a similar structure and function to the VR optical system 100 in the first embodiment. The main differences are: the focal lengths of the microlens units on the first microlens array L2 and the microlens units on the second microlens array L3 are different; the microlens units on the first surface S5 of the second microlens array L3 are concave; there is an air gap between the first and second microlens arrays; and the focal lengths, curvatures, and spacing of the optical lens L1 and the first and second microlens arrays are different. Specifically, in this embodiment, the focal length of the optical lens L1 is 25.1 mm, the focal length of the microlens units on the first surface S3 of the first microlens array L2 is 7.42 mm, and the focal length of the microlens units on the first surface S5 of the second microlens array L3 is -20.6 mm. The specific parameters of the VR optical system 200 in this embodiment are shown in Table 3 below.

[0077] Table 3

[0078]

[0079] In this embodiment, the first surface S1 and the second surface S2 of the optical lens L1 are both aspherical surfaces, and the surface coefficients of each aspherical surface are shown in Table 4 below.

[0080] Table 4

[0081] Face number k <![CDATA[A4]]> <![CDATA[A6]]> <![CDATA[A8]]> <![CDATA[A 10 ]]> S1 -10.071 2.363E-003 -2.360E-005 -1.710E-008 7.342E-011 S2 57.444 7.411E-003 -1.711E-006 -1.246E-007 -1.474E-010

[0082] Based on the settings in Tables 3 and 4, the VR optical system 200 has an ultra-large field of view of 90° per eye, and a relatively small overall thickness (total optical length TTL of 14.617 mm). Furthermore, the imaging quality across all fields of view is significantly improved, such as... Figure 5 The image shows the MTF curve of the VR optical system 200 provided by this invention. As can be seen from the MTF performance graph, the central field of view of the VR optical system 200 has an MTF value greater than 30% across the entire frequency range of 14 l p / mm, achieving clearer image quality and meeting the imaging requirements of the human eye. Therefore, the VR optical system 200 provided by this invention, when applied, can have a larger field of view, a more compact structure, lighter weight, and clearer resolution throughout the entire field of view, effectively improving the user's visual experience.

[0083] Third Embodiment

[0084] Figure 6 This is a schematic diagram of the structure of the VR optical system 300 provided in the third embodiment of the present invention. The VR optical system 300 in this embodiment has a similar structure and function to the VR optical system 100 in the first embodiment, with the main difference being:

[0085] (1) Each microlens unit on the first microlens array L2 has a different focal length, and each microlens unit on the second microlens array L3 also has a different focal length. However, the focal lengths of the microlens units at corresponding positions on the first and second microlens arrays are the same. Assume that the microlens units on the microlens array from the optical axis of the system to the edge of the lens are labeled Z1, Z2, and Z3 in sequence. The specific radius of curvature and corresponding focal length of each microlens unit are shown in Table 7. For example, the radius of curvature of microlens unit Z1 at the center of the optical axis is 11.359 mm, and the corresponding focal length of microlens unit Z1 at this location is 12.6 mm; the radius of curvature of microlens unit Z2 is 10.409 mm, and the corresponding focal length of microlens unit Z2 at this location is 11.6 mm; the radius of curvature of microlens unit Z3 is 11.819 mm, and the corresponding focal length of microlens unit Z3 at this location is 13.1 mm. Specifically, the microlens units in the first and second microlens arrays are all microconvex lenses, and the focal length and radius of curvature at corresponding positions are the same, which is beneficial for fabrication.

[0086] (2) The focal length, curvature, and spacing of the optical lens L1 and the first and second microlens arrays are different. Specifically, in this embodiment, the focal length of the optical lens L1 is 31.5 mm, the first surface S3 of the first microlens array L2 is convex, and the first surface S7 of the second microlens array L3 is convex.

[0087] Specifically, the parameters of the VR optical system 300 in this embodiment are shown in Table 5 below.

[0088] Table 5

[0089]

[0090]

[0091] In this embodiment, the aspherical surface coefficients of the first surface S1 and the second surface S2 of the optical lens L1 are shown in Table 6 below.

[0092] Table 6

[0093] Face number k <![CDATA[A4]]> <![CDATA[A6]]> <![CDATA[A8]]> <![CDATA[A 10 ]]> S1 -4.252 4.507E-003 -2.695E-005 -4.539E-008 3.265E-011 S2 28.434 2.741E-003 -5.621E-006 -1.020E-007 -8.498E-011

[0094] Table 7

[0095]

[0096] In this embodiment, the first and second microlens arrays are optimized by establishing a multi-layered structure. Different fields of view correspond to microlens units at different positions, and the focal length of the microlens units at different positions is different. Since the focal lengths of the microlens units at different positions are different, the refraction direction and degree of refraction of the incident light are different. This not only helps to expand the field of view, but also allows for targeted optimization of different fields of view passing through different microlens units, which can obtain better MTF values ​​and reduce the RMS (Root Mean Square) radius value to improve imaging quality.

[0097] Based on the settings in Tables 5, 6, and 7, the VR optical system 300 has an ultra-large field of view of 92° per eye, a relatively small overall thickness (total optical length TTL of 12.504 mm), and significantly improved imaging quality across all fields of view, such as... Figure 7 The figure shows the MTF curve of the VR optical system 300 provided by the present invention. It can be seen from the MTF performance graph that the MTF value of the center field of view of the VR optical system 300 at the full frequency of 14l p / mm is greater than 23%, which is flatter than the MTF value of the VR optical system 100 at the full frequency in the first embodiment. This results in clearer imaging and a larger field of view, which can better meet the imaging requirements of the human eye.

[0098] In this embodiment, both the first and second microlens arrays adopt the structure of convex microlenses, which has higher specificity. Especially when it involves highly compact component integration or when it is necessary to improve the stability of the system, the optical path of the dual convex microlens array is more advantageous.

[0099] Fourth embodiment

[0100] Figure 8 This is a schematic diagram of the structure of the VR optical system 400 provided in the fourth embodiment of the present invention. The VR optical system 400 in this embodiment has a similar structure and function to the VR optical system 300 in the third embodiment, with the main difference being:

[0101] (1) Each microlens unit on the first microlens array L2 has a different focal length, and each microlens unit on the second microlens array L3 also has a different focal length. Furthermore, the focal lengths of the microlens units at corresponding positions on the first and second microlens arrays are not the same. The specific radius of curvature and corresponding focal length of each microlens unit are shown in Table 10.

[0102] (2) The focal length, curvature, and spacing of the optical lens L1 and the first and second microlens arrays are different. Specifically, in this embodiment, the focal length of the optical lens L1 is 33mm, the first surface S3 of the first microlens array L2 is convex, and the first surface S7 of the second microlens array L3 is convex.

[0103] Specifically, the parameters of the VR optical system 400 in this embodiment are shown in Table 8 below.

[0104] Table 8

[0105]

[0106] In this embodiment, the aspherical surface coefficients of the first surface S1 and the second surface S2 of the optical lens L1 are shown in Table 9 below.

[0107] Table 9

[0108] Face number k <![CDATA[A4]]> <![CDATA[A6]]> <![CDATA[A8]]> <![CDATA[A 10 ]]> S1 -4.311 4.177E-003 -2.669E-005 -4.159E-008 1.932E-011 S2 29.382 2.691E-003 -5.916E-006 -1.023E-007 8.923E-011

[0109] Table 10

[0110]

[0111] In this embodiment, the first and second microlens arrays are optimized by establishing a multi-layered structure. Different fields of view correspond to microlens units at different positions, and the focal lengths of the microlens units at different positions are different. Because the focal lengths of the microlens units at different positions are different, the refraction direction and degree of refraction of the incident light are different. This not only helps to expand the field of view, but also allows for targeted optimization of different fields of view through different microlens units, resulting in better MTF values ​​and reduced RMS radius values ​​to improve imaging quality.

[0112] Based on the settings in Tables 8, 9, and 10, the VR optical system 400 has an ultra-large field of view of 92° per eye, a relatively small overall thickness (total optical length TTL of 12.538 mm), and significantly improved imaging quality across all fields of view, such as... Figure 9 The figure shows the MTF curve of the VR optical system 400 provided by the present invention. It can be seen from the MTF performance graph that the MTF value of the center field of view of the VR optical system 400 at the full frequency of 14lp / mm is greater than 80%. Compared with the VR optical systems in the first, second and third embodiments, the MTF value of the center field of view of the VR optical system 400 in this embodiment is greatly improved, thereby obtaining a clearer image.

[0113] In this embodiment, the VR optical system 400 optimizes the microlens units in the first and second microlens arrays by establishing multiple structures. In particular, the focal lengths of the first and second microlens arrays are different, so that each microlens unit can obtain the optimal structure. This can not only effectively improve the imaging quality of the edge field of view, but also shorten the distance from the microlens array to the display screen.

[0114] Fifth Embodiment

[0115] Figure 10This is a schematic diagram of the structure of the VR optical system 500 provided in the fifth embodiment of the present invention. The VR optical system 500 in this embodiment has a similar structure and function to the VR optical system 300 in the third embodiment, with the main difference being:

[0116] (1) Each microlens unit on the first microlens array L2 has a different focal length, and each microlens unit on the second microlens array L3 also has a different focal length. Furthermore, the focal lengths of the microlens units at corresponding positions on the first and second microlens arrays are not the same. The specific radius of curvature and corresponding focal length of each microlens unit are shown in Table 13.

[0117] (2) The focal length, curvature, and spacing of the optical lens L1 and the first and second microlens arrays are different. Specifically, in this embodiment, the focal length of the optical lens L1 is 34mm, the first surface S3 of the first microlens array L2 is convex, and the first surface S7 of the second microlens array L3 is convex.

[0118] (3) The incident light of the VR optical system is emitted by the curved display screen. Since the human eyeball is convex and curved, the curvature of the curved screen can ensure that the distance of the emitted light to the eye is equal, thus the curved screen can bring a better sensory experience.

[0119] Specifically, the parameters of the VR optical system 500 in this embodiment are shown in Table 11 below.

[0120] Table 11

[0121]

[0122] In this embodiment, the aspherical surface coefficients of the first surface S1 and the second surface S2 of the optical lens L1 are shown in Table 12 below.

[0123] Table 12

[0124] Face number k <![CDATA[A4]]> <![CDATA[A6]]> <![CDATA[A8]]> <![CDATA[A 10 ]]> S1 -4.245 3.891E-003 -2.553E-005 -3.355E-008 -2.267E-011 S2 28.411 2.699E-003 -5.865E-006 -1.018E-007 9.355E-011

[0125] Table 13

[0126]

[0127]

[0128] In this embodiment, the first and second microlens arrays are optimized by establishing a multi-layered structure. Different fields of view correspond to microlens units at different positions, and the focal length of the microlens units at different positions is different. Because the focal lengths of the microlens units at different positions are different, the refraction direction and degree of refraction of the incident light are different. This not only helps to expand the field of view, but also allows for targeted optimization of different fields of view passing through different microlens units. At the same time, since the incident light is image light emitted from the curved display screen, a better MTF value can be obtained.

[0129] According to Tables 11, 12, and 13, the VR optical system 500 has an ultra-large field of view of 92° per eye, a relatively small overall thickness (total optical length TTL of 12.542 mm), and significantly improved imaging quality across all fields of view, such as... Figure 11 The figure shows the MTF curve of the VR optical system 500 provided by the present invention. It can be seen from the MTF performance graph that the MTF value of the central field of view of the VR optical system 500 at all frequencies of 14 l p / mm is greater than 90%. Compared with the VR optical systems in the first, second and third embodiments, the MTF value of the central field of view of the VR optical system 500 in this embodiment has been greatly improved, thereby obtaining clearer imaging. Compared with the fourth embodiment, the curved screen setting in this embodiment also helps to improve the MTF, which is beneficial to improving the aberration problem caused by edge field of view imaging.

[0130] In this embodiment, both the first and second microlens arrays employ microconvex lenses, which can give the VR optical system better light-gathering ability. At the same time, the image light emitted from the curved display screen is used as the incident light of the VR optical system. The curvature of the curved screen can ensure that the distance of the emitted light to the human eye is equal, thereby bringing a better sensory experience.

[0131] Sixth Embodiment

[0132] Figure 12 This is a schematic diagram of the structure of the VR optical system 600 provided in the sixth embodiment of the present invention. The VR optical system 600 in this embodiment has a similar structure and function to the VR optical system 300 in the third embodiment, with the main difference being:

[0133] (1) Each microlens unit on the first microlens array L2 has a different focal length, and each microlens unit on the second microlens array L3 also has a different focal length. Furthermore, the focal lengths of the microlens units at corresponding positions on the first and second microlens arrays are not the same. The specific radius of curvature and corresponding focal length of each microlens unit are shown in Table 16.

[0134] (2) The second surface S2 of the optical lens L1 is convex near the optical axis; the microlens units on the second microlens array L3 have both convex and concave surfaces, and the focal length, curvature, and spacing of the optical lens L1, the first microlens array, and the second microlens array are different. Specifically, in this embodiment, the focal length of the optical lens L1 is 30mm, the first surface S3 of the first microlens array L2 is convex, and the microlens units on the first surface S5 of the second microlens array L3 have both convex and concave surfaces. See Table 16 for the radius of curvature of each microlens unit. For example, the radius of curvature of microlens unit Z1 at the optical axis center of the first surface S5 of the second microlens array L3 is 73.009mm, the surface of this microlens unit is convex, and the corresponding focal length is 81.2mm; the radius of curvature of microlens unit Z2 is -37.981mm, the surface of this microlens unit is concave, and the corresponding focal length is -42.2mm; the radius of curvature of microlens unit Z3 is -13.326mm, the surface of this microlens unit is concave, and the corresponding focal length is -14.8mm.

[0135] (3) Instead of a glass substrate, there is an air gap between the first microlens array L2 and the second microlens array L3. The substrate between the two microlens arrays is air, which helps to reduce the weight of the VR system.

[0136] Specifically, the parameters of the VR optical system 600 in this embodiment are shown in Table 14 below.

[0137] Table 14

[0138]

[0139]

[0140] In this embodiment, the aspherical surface coefficients of the first surface S1 and the second surface S2 of the optical lens L1 are shown in Table 15 below.

[0141] Table 15

[0142] Face number k <![CDATA[A4]]> <![CDATA[A6]]> <![CDATA[A8]]> <![CDATA[A 10 ]]> S1 -11.461 1.679E-003 -2.504E-005 -2.302E-008 2.997E-011 S2 81080 4.871E-003 -4.205E-006 -1.331E-007 -1.738E-010

[0143] Table 16

[0144]

[0145] According to Tables 14, 15, and 16, the VR optical system 600 has an ultra-large field of view of 92° per eye, a relatively small overall thickness (total optical length TTL of 15.361 mm), and significantly improved imaging quality across all fields of view, such as... Figure 13The figure shows the MTF curve of the VR optical system 600 provided by the present invention. It can be seen from the MTF performance graph that the MTF value of the center field of view of the VR optical system 600 at all frequencies of 14 l p / mm is greater than 30%. Compared with the VR optical systems in the first and second embodiments, the MTF value of the center field of view of the VR optical system 600 in this embodiment is improved to a certain extent, thereby obtaining clearer imaging. Compared with the fourth embodiment, the curved screen setting in this embodiment also helps to improve the MTF, which is beneficial to improving the aberration problem caused by edge field of view imaging.

[0146] In this embodiment, the first microlens array L2 uses a positive optical power microconvex lens unit, and the second microlens array L3 uses a negative optical power microconcave lens unit. This combination of positive and negative microlens arrays has high specificity, can better eliminate aberrations at large angles, and has advantages in optical path, thus improving the overall imaging clarity.

[0147] Please refer to Table 17, which shows the relevant values ​​for the VR optical systems provided in the above six embodiments and each of the aforementioned conditional expressions.

[0148]

[0149] Seventh Embodiment

[0150] Figure 14This is a schematic diagram of a near-eye display device 1000 provided in an embodiment of the present invention. The near-eye display device 1000 includes, along the light incident direction OX from the display side to the human eye side, a display element 10, a second microlens array L3, a glass substrate G1 or an air gap, a first microlens array L2, and an optical lens L1. The display element 10 is used to emit light signals, which include image information. The second microlens array L3, the glass substrate G1 or an air gap, the first microlens array L2, and the optical lens L1 constitute a VR optical system 20. The optical system 20 can be selected from any one of the optical systems 100 / 200 / 300 / 400 / 500 / 600 in the aforementioned embodiments. The VR optical system 20 is disposed in the light-emitting direction of the display element 10, wherein the second microlens array L3 is closer to the light-emitting surface of the display element 10 than the optical lens L1. The VR optical system 20 is used to modulate the light signal emitted by the display element 10 so that the human eye can receive the modulated image information. The light propagation path in the near-eye display device 1000 is as follows: the light signal (image information) emitted by the display element 10 is transmitted to the optical lens L1 via the microlens arrays L3 and L2. After being collected by the optical lens L1, the light signal is transmitted to the human eye 30 (human eye side). The human eye can form a virtual, magnified image at a distance (a distance in front of the pupil). Therefore, the user wearing the near-eye display device can see intuitive and visible images and video information.

[0151] In summary, the VR optical system and near-eye display device provided by this invention, by setting an optical lens close to the human eye and at least one microlens array close to the display side, especially with each microlens unit in the microlens array having the same or different focal lengths, can establish multiple fields of view and optimize the field of view within each small range, thereby obtaining clearer imaging quality and improving the resolution of the VR system. At the same time, due to the reasonable combination of optical lenses and microlens arrays, not only can the overall thickness of the VR optical system be effectively reduced, but the imaging quality of the system at the field of view angle can also be effectively improved. This enables the mounted near-eye display device to have a larger field of view angle, a more compact structure, and clearer resolution throughout the entire field of view, effectively improving the user's visual experience.

[0152] Finally, it should be noted that the above descriptions are merely embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A VR optical system, characterized in that, It consists of an optical lens and two microlens arrays, and successively includes, from the human eye side to the display side, the optical lens close to the human eye side, the first microlens array close to the optical lens, and the second microlens array close to the display side; The optical lens has a positive optical power. The optical lens has a first surface close to the human eye side and a second surface far from the human eye side. At least one of the first surface and the second surface of the optical lens is an aspherical surface, and the first surface of the optical lens is a convex surface; The first microlens array has a first surface and a second surface arranged oppositely. The first surface of the first microlens array faces the human eye side, and the second surface of the first microlens array faces the display side; The second microlens array has a first surface and a second surface arranged oppositely. The first surface of the second microlens array faces the human eye side, and the second surface of the second microlens array faces the display side; Both the first microlens array and the second microlens array have a plurality of microlens units. The focal lengths of the microlens units of the first microlens array and the microlens units of the second microlens array are the same or different; and the microlens units at different positions on the first microlens array and the second microlens array adopt different focal lengths, and cooperate with the optical lens to establish multiple fields of view and optimize the field of view in each small range; The focal length of the microlens units of the first microlens array is positive; Among them, the VR optical system satisfies the following conditional formula: 1.5 < TTL / (f×tanθ) < 3, where TTL represents the total optical length of the VR optical system, f represents the effective focal length of the VR optical system, and θ represents the maximum half field angle of the VR optical system.

2. The VR optical system according to claim 1, characterized in that, The focal length of the microlens units of the second microlens array is positive or negative.

3. The VR optical system according to claim 1, characterized in that, The thicknesses of the first microlens array and the second microlens array in the optical axis direction and the widths perpendicular to the optical axis direction are equal.

4. The VR optical system according to claim 3, characterized in that, The effective aperture of the optical lens is smaller than the width of the first microlens array or the second microlens array in the direction perpendicular to the optical axis.

5. The VR optical system according to claim 1, characterized in that, A glass substrate or an air gap is provided between the first microlens array and the second microlens array.

6. The VR optical system according to claim 1, characterized in that, The VR optical system satisfies the conditional formula: f1 / f > 2; Among them, f1 represents the focal length of the optical lens.

7. The VR optical system according to claim 1, characterized in that, The VR optical system satisfies the conditional formula: -0.01 < R1 / R2 < 0.5; Among them, R1 represents the radius of curvature of the first surface of the optical lens, and R2 represents the radius of curvature of the second surface of the optical lens.

8. The VR optical system according to claim 1, characterized in that, The VR optical system satisfies the conditional formula: 1.2 < CT1 / CT23 < 2.0; Among them, CT1 represents the thickness of the optical lens on the optical axis, and CT23 represents the thickness on the optical axis from the first surface of the first microlens array to the second surface of the second microlens array.

9. A near-eye display device, characterized in that, It includes: A display element, which is used to emit an optical signal, and the optical signal includes image information; The VR optical system according to any one of claims 1-8, wherein the VR optical system is disposed in the light-emitting direction of the display element, wherein the second microlens array is closer to the light-emitting surface of the display element than the optical lens; the VR optical system is used to modulate the light signal emitted by the display element so that the modulated image information can be received by the human eye.

10. The near-eye display device according to claim 9, characterized in that, The distance on the optical axis from the display element to the second surface of the second microlens array is less than the effective focal length of the VR optical system.

11. The near-eye display device according to claim 9, characterized in that, The display element is a curved display screen or a flat display screen.

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