Optical module, near-to-eye display device and optical module processing method

Abstract

The embodiment of the invention discloses an optical module, a near-to-eye display device and an optical module processing method, and the optical module comprises a substrate which comprises a first end and a second end which are opposite to each other; the first reflecting surface is arranged at the first end of the base body and is configured to allow light to be reflected; the second reflecting surface is arranged at the second end of the base body and is configured to receive the light rays reflected by the first reflecting surface and reflect the light rays again; the incident plane is arranged at the second end of the base body and is surrounded by the second reflecting plane; the emergent surface is arranged at the first end of the base body and surrounds the first reflecting surface; one end of the annular side surface is connected with the second reflecting surface; the incident surface and the emergent surface are one or a combination of an aspheric surface, a spherical surface and a free-form surface, the incident surface is configured to receive light from an image of the micro display, and the light enters the substrate through the incident surface, is reflected by the first reflecting surface, is then reflected by the second reflecting surface, and leaves the substrate through the emergent surface. The field angle is effectively increased, the imaging quality of an image is better, and the optical efficiency is higher.

Description

Technical Field

[0001] The present application relates to the field of augmented reality technology, and particularly to an optical module, a near-eye display device, and a method for processing an optical module. Background Art

[0002] Augmented Reality (AR) technology is a technology that "seamlessly" integrates real-world information and virtual-world information. By processing certain information that is difficult to experience in the real world through technologies such as images, data, and optics, people can obtain an experience of virtual-reality combination. Due to the characteristic of the augmented reality technology of superimposing virtual objects or images in a real environment, it has shown great application potential in many fields. In recent years, various intelligent devices such as smart glasses, helmets, and head-up displays have become increasingly popular.

[0003] Since head-mounted devices are often worn for a long time, smaller-sized and lighter head-mounted devices are the goals pursued by major manufacturers. Existing modules such as Prism technology still tend to be relatively heavy and large in volume, while the optical efficiency of waveguide technology is low. The above-mentioned existing technologies will greatly change the appearance, structural form, etc. of traditional ordinary glasses such as myopia, hyperopia, eye protection, and sunglasses, or head-mounted devices such as helmets. It has become extremely difficult for the existing technology solutions to be combined with existing traditional glasses, helmets, and other head-mounted devices. In addition, as a device that needs to transmit information to the human eye retina, taking a head-mounted device as an example, it is very important that the content in the visual field range of the human eye retina can be clearly and completely presented. In the case of combining virtual and real scenarios, obtaining relatively more virtual information content in the visual field has also become an increasingly important functional requirement. Higher-quality images and higher light efficiency are also very important. Being lighter, smaller in size, and compatible with various head-mounted devices has become an urgent problem to be solved. Summary of the Invention

[0004] Embodiments of the present application provide an optical module, a near-eye display device, and a method for processing an optical module to improve at least one of the above technical problems. The embodiments of the present application have a larger field of view, better image presentation, and higher light efficiency. Other beneficial effects of the present application will be presented in the following embodiments.

[0005] In a first aspect, an embodiment of the present application provides an optical module applied to a near-eye display device, including:

[0006] A substrate, including opposite first and second ends; a first reflecting surface disposed at the first end of the substrate and configured to allow reflection of light; a second reflecting surface disposed at the second end of the substrate and configured to receive light reflected from the first reflecting surface and reflect it again; an incident surface disposed at the second end of the substrate and surrounded by the second reflecting surface; an exit surface disposed at the first end of the substrate and surrounding the first reflecting surface; an annular side surface having one end connected to the second reflecting surface and the other end connected to the exit surface;

[0007] Wherein, the incident surface and the exit surface are one or a combination of aspherical surfaces, spherical surfaces, and free-form surfaces. The incident surface is configured to receive light from a microdisplay image. The light enters the substrate through the non-planar incident surface, is reflected by the first reflecting surface, then reflected by the second reflecting surface, and exits the substrate through the non-planar exit surface.

[0008] In a second aspect, an embodiment of the present application provides a near-eye display device, including: a microdisplay, and the above optical module, where the microdisplay is located at the incident surface.

[0009] In a third aspect, an embodiment of the present application further provides a processing method for an optical module, the optical module being the above optical module, and the processing method includes the following steps:

[0010] Form a substrate;

[0011] Form an exit surface and a first reflecting surface located at the center of the exit surface at the first end of the substrate; wherein, the exit surface is one or a combination of an aspherical surface, a spherical surface, and a free-form surface;

[0012] Form an incident surface and a second reflecting surface surrounding the circumferential direction of the incident surface at the second end of the substrate; the incident surface is one or a combination of an aspherical surface, a spherical surface, and a free-form surface;

[0013] Deposit a reflective film on the first reflecting surface and the second reflecting surface. Wherein, the incident surface is configured to receive light from a microdisplay image. The light enters the substrate through the incident surface, is reflected by the first reflecting surface, then reflected by the second reflecting surface, and exits the substrate through the exit surface.

[0014] The optical module, near-eye display device, and optical module processing method provided by the embodiments of the present application change the original incident surface and exit surface from planar to one or a combination of aspherical surfaces, spherical surfaces, and free-form surfaces, so that the image light of the microdisplay enters through the non-planar incident surface, then enters the substrate to the first reflecting surface, is reflected to the second reflecting surface, and finally exits the substrate through the non-planar exit surface (not a plane). The coaxial folding optical path effectively reduces light loss, and the design of the non-planar incident surface for light input and the non-planar exit surface for light output effectively increases the field of view angle, and the image imaging quality is better and the optical efficiency is higher. Description of the Drawings

[0015] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0016] Figure 1 It is a schematic structural diagram of an embodiment of the optical module provided by the embodiment of the present application;

[0017] Figure 2 It is a schematic structural diagram of another embodiment of the optical module provided by the embodiment of the present application;

[0018] Figure 3 It is a schematic diagram of an embodiment of the contour of each relevant surface of the optical module provided by the embodiment of the present application;

[0019] Figure 4 It is a schematic three-dimensional structural diagram of an embodiment of the optical module provided by the embodiment of the present application;

[0020] Figure 5 It is a schematic three-dimensional structural diagram of another embodiment of the optical module provided by the embodiment of the present application;

[0021] Figure 6 It is a schematic three-dimensional structural diagram of another embodiment of the optical module provided by the embodiment of the present application;

[0022] Figure 7 It is a schematic three-dimensional structural diagram of another embodiment of the optical module provided by the embodiment of the present application;

[0023] Figure 8 It is a schematic structural diagram of an embodiment of the optical module with an optical path provided by the embodiment of the present application;

[0024] Figure 9 It is a schematic structural diagram of another embodiment of the optical module provided by the embodiment of the present application;

[0025] Figure 10 It is a schematic structural diagram of another embodiment of the optical module with an optical path provided by the embodiment of the present application;

[0026] Figure 11 It is a schematic structural diagram of another embodiment of the optical module provided by the embodiment of the present application;

[0027] Figure 12 It is a schematic three-dimensional structural diagram of another embodiment of the optical module provided by the embodiment of the present application;

[0028] Figure 13 It is a schematic structural diagram of another embodiment of the optical module provided by the embodiment of the present application;

[0029] Figure 14 It is a schematic structural diagram of the application scenario of the optical module provided by the embodiment of the present application in the eyeball;

[0030] Figure 15 It is a schematic flow chart of an embodiment of the processing method of the optical module provided by the embodiment of the present application. Specific embodiment

[0031] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0032] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

[0033] In the present application, the term "exemplary" is used to mean "serving as an example, illustration, or description". Any embodiment described as "exemplary" in the present application is not necessarily to be construed as more preferred or more advantageous than other embodiments. In order for any person skilled in the art to implement and use the present application, the following description is given. In the following description, details are set forth for the purpose of explanation. It should be understood that those skilled in the art can recognize that the present application can be implemented without using these specific details. In other instances, well-known structures and processes are not elaborated in detail to avoid unnecessary details from obscuring the description of the present application. Therefore, the present application is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed in the present application.

[0034] The embodiment of the present application provides an optical module 100, which will be described in detail below.

[0035] The optical module 100 can be applied to a near-eye display device 200, for example, it can be applied in augmented reality (AR), virtual reality (VR), mixed reality (MR), extended reality (XR), goggles, smart glasses, myopia glasses, hyperopia glasses, sports glasses, contact lenses, helmets, or other related near-eye display devices. Refer to Figure 1-14 Figure, the optical module 100 includes a base body 10, which includes opposite first end 12 and second end 14. The base body 10 can be solid, for example, the material used can be a transparent or light-transmitting hard and machinable material, such as PMMA (polymethyl methacrylate), PC (polycarbonate) plastic, resin, glass, etc.; for example, it can be a regular shape such as a cylindrical shape, a prismatic shape, or a frustum shape, and of course, it can also be an irregular shape, etc. In some other embodiments, the base body 10 can also have a hollow structure, for example, it can be formed by bonding at least two groups of thin walls with optical glue, and the center can be hollow. The first reflecting surface 20, the second reflecting surface 30, the incident surface 40, the exit surface 50, etc. can be formed on the thin walls.

[0036] The first reflecting surface 20 is disposed at the first end 12 of the base body 10 and is configured to allow the reflection of light;

[0037] The second reflecting surface 30 is disposed at the second end 14 of the base body 10 and is configured to receive the light reflected from the first reflecting surface 20 and reflect it again; it can be understood that the first end 12 and the second end 14 can be opposite ends. The first reflecting surface 20 and the second reflecting surface 30 can be provided with a reflective material, which can be a metal or a metal alloy and other reflective materials, such as aluminum, silver, or a mixture of aluminum and silver, etc.

[0038] The incident surface 40 is disposed at the second end 14 of the base body 10 and is surrounded by the second reflecting surface 30;

[0039] The exit surface 50 is disposed at the first end 12 of the base body 10 and is disposed around the first reflecting surface 20; the size of the exit surface 50 can be the same as the size of the second reflection window 1312, and in some other embodiments, the size of the exit surface 50 can also be different from the size of the second reflection window 1312;

[0040] The annular side surface 60 has one end connected to the second reflecting surface 30 and the other end connected to the exit surface 50.

[0041] Among them, the incident surface 40 and the exit surface 50 are one or a combination of aspherical surfaces, spherical surfaces, and free-form surfaces. The incident surface 40 is configured to receive the light beam L of the image from the micro display 80. The light beam enters the substrate 10 through the non-planar (but one or a combination of aspherical surfaces, spherical surfaces, and free-form surfaces) incident surface 40, is reflected by the first reflecting surface 20, then is reflected by the second reflecting surface 30, and leaves the substrate 10 through the non-planar exit surface 50. The micro display 80 can be, for example, Micro-LED (Micro Light-Emitting Diode), uLED (micro light-emitting diode), Micro-oled (Micro Organic Light-Emitting Diode), LCoS (Liquid Crystal On Silicon), LCD (Liquid Crystal Display), DMD (Digital Micromirror Device) / DLP (Digital Light Processing), or LBS (Laser Beam Scanning), etc., or any combination of these technologies. In some embodiments, the optical module can be combined with existing ordinary glasses such as myopia glasses, hyperopia glasses, eye protection glasses, and sports glasses to achieve the function of enhanced display, so that the ordinary glasses have the augmented reality function of smart glasses. It can be understood that the black or shaded areas of the respective reflecting surfaces (such as the first reflecting surface 20 and the second reflecting surface 30) in the related drawings of the present application (such as 1-2, 8-11, etc.) only exemplify that they have a reflective layer and do not represent the actual thickness design.

[0042] It can be understood that in the prior art, in order to better make the microdisplay 80 fit the incident surface 40 (such as bonding with optical glue, etc.), the incident surface 40 is generally a plane, and to ensure the integrity of the entire module during subsequent packaging (such as a regular cylinder as a whole, etc.), the exit surface 50 is also often designed as a plane. However, the research of this application finds that based on the size requirements in product design, such as miniaturization, light weight, and combination with existing glasses, the sizes of components such as the incident surface, the first and second reflection surfaces, and the exit surface cannot be increased arbitrarily. At this time, the optical module is limited to a small size within a fixed range, such as less than 5mm * 5mm * 5mm or even smaller sizes, etc. This application changes the original incident surface and exit surface from a plane to an aspherical surface, a spherical surface, a free-form surface, or a combination thereof, and fully redesigns the shape and structure of each surface, so that the image light L of the microdisplay 80 enters from the non-planar incident surface 40, where the incident surface 40 is one or a combination of an aspherical surface, a spherical surface, and a free-form surface, then enters the substrate 10 to the first reflection surface 20, is reflected to the second reflection surface 30, and finally leaves the substrate 10 through the non-planar exit surface 50. The exit surface 50 can be one or a combination of an aspherical surface, a spherical surface, and a free-form surface. The light L ( Figure 8 ) from the edge or near the edge of the microdisplay 80 is more likely to converge towards the optical axis direction, while the light L from the edge or near the edge of the microdisplay 80 with the existing planar incident surface and exit surface cannot converge towards the direction close to the optical axis. Therefore, the utilization rate of the light from the edge or near the edge of the microdisplay 80 is effectively improved, the light loss is effectively reduced, the light efficiency is effectively improved, and the light rays in the prior art are not easily converged towards the optical axis, resulting in a smaller field of view. This application makes full use of the light L at the center and the edge to effectively improve the field of view. On the other hand, the folded optical path effectively reduces the size of the entire optical system, making the entire module more portable. The shorter reflection path reduces the light loss and effectively improves the light efficiency, and the overall imaging quality is better.

[0043] In some embodiments, the lateral dimension of the annular side surface 60 has a decreasing trend along the connection direction from the second reflection surface 30 to the exit surface 50, that is, the maximum outer contour dimension of the exit surface 50 can be smaller than the maximum outer contour dimension of the second reflection surface 30, so as to ensure that the light L entering from the edge of the incident surface 40 of the microdisplay 80 effectively converges to the position of the central optical axis Z, further effectively improving the field of view and the image imaging quality is better.

[0044] In some embodiments, with reference to Figure 3, the first reflection surface 20 and the second reflection surface 30 are one or a combination of total internal reflection surfaces of aspherical, spherical, and free-form surfaces. It can be understood that this kind of reflection can effectively reduce optical loss and improve light efficiency and imaging quality. Among them, the incident surface 40 includes a first section and a second section from the center to the periphery. The first section is bent in the first direction of the optical axis Z. The first direction can be the positive direction of the optical axis Z (the light emitting direction). The second section is bent in the second direction of the optical axis Z opposite to the first direction. The second direction can be the negative direction of the optical axis Z (away from the light emitting direction). The first reflection surface 20, the second reflection surface 30, and the exit surface 50 are bent in the first direction of the optical axis Z, that is, bent in the positive direction of the optical axis Z. It can be understood that the first section of the incident surface 40 corresponds to an area of ​​the microdisplay 80 that is the center or close to the center of the microdisplay 80, and the second section corresponds to an area of ​​the microdisplay 80 that is the edge or close to the edge (relatively far from the center) of the microdisplay 80. Therefore, the light at the edge or close to the edge of the microdisplay 80 can be reflected to the edge or close to the edge of the first reflecting surface 20 as much as possible, and then further reflected by the first reflecting surface 20 to the edge or close to the edge of the second reflecting surface 30. Finally, the non-planar exit surface 50 makes the light move closer to the center of the optical axis Z, thereby effectively improving the utilization rate of the light at the edge or close to the edge of the microdisplay 80, thereby improving the lighting effect and imaging quality. The first reflecting surface 20, the second reflecting surface 30, the exit surface 50 and the incident surface 40 may all adopt a non-planar design, for example, they may be a non-spherical surface, a spherical surface, a free-form surface or a combination thereof, but their bending directions may be different, wherein the first reflecting surface 20, the second reflecting surface 30 and the exit surface 50 may be the same, as described in Table 1 below, the sagittal values ​​of the first reflecting surface 20, the second reflecting surface 30 and the exit surface 50 are positive values, the sagittal value of the incident surface 40 is positive in the range of 0-0.6mm, and is negative in the range of 0.65-0.85mm, it can be seen that the incident surface 40 is first bent toward the positive direction of the optical axis and then toward the negative direction of the optical axis, and the design of other surfaces can effectively increase the field of view of the exiting light, improve the light effect, and achieve better image quality.

[0045] In some embodiments, the second reflecting surface 30, the exiting surface 50, the incident surface 40, and the first reflecting surface 20 have a projection profile shape on the plane where the vertical optical axis Z is located. The profile shape can be a circle, an ellipse, a polygon, a rounded rectangle, a trapezoid, or other geometric figures. The plane where the vertical optical axis Z is located can be, for example, a cross section, or a plane where a top view or a bottom view corresponding to the first end 12 or the second end 14 is located. Among them, the profile shapes of the incident surface 40 and the first reflecting surface 20 can be similar to each other, and the profile shapes of the second reflecting surface 30 and the exiting surface 50 can be similar to each other. In other embodiments, such as Figure 9As shown, the contour shape of the incident surface 40 can also be similar to the contour shape of the second reflecting surface 30; the contour shape of the exit surface 50 can also be similar to the contour shape of the first reflecting surface 20, for example, both are regular polygons, etc. It can be understood that the geometric shapes of the relevant surfaces can be flexibly designed according to the outer contour of the microdisplay 80 or the overall outer contour to meet the assembly requirements of different sizes and shapes, and fully obtain the light from the microdisplay 80. On the other hand, the second reflecting surface 30, the exit surface 50, the incident surface 40, and the first reflecting surface 20 can all be the same, for example, all are one of circular, elliptical, or regular polygon contours, so that the light of the microdisplay 80 can be fully reflected and utilized to achieve better imaging quality and light output efficiency.

[0046] In some embodiments, with reference to Figure 1 , 3 -5, the first reflecting surface 20 includes a first vertex O2, the second reflecting surface 30 includes a second vertex O3, the incident surface 40 includes a third vertex O4, and the exit surface 50 includes a fourth vertex O5; the first vertex O2, the second vertex O3, the third vertex O4, and the fourth vertex O5 are located on the optical axis Z. The incident surface 40, the first reflecting surface 20, the second reflecting surface 30, and the exit surface 50 are symmetrically designed with respect to the cross-section where the optical axis is located to ensure that the optical module 100 is not eccentric, that is, there will be no situation where the optical path area on one side is much larger or smaller than the optical path area on the other side. It can be understood that the second vertex Q3 can be the point formed by the final intersection of the curved surface of the second reflecting surface 30 after being extended centrally relative to the center of the incident surface 40. Figure 3 (The dotted line in (b) indicates its central extension to form the second vertex Q3. Similarly, the fourth vertex Q5 can be the point formed by the final intersection of the curved surface of the exit surface 50 after being extended centrally relative to the center of the first reflecting surface 20. Figure 3 (The dotted line in (d) indicates its central extension to form the fourth vertex Q5. It can be understood that the vertices of the second reflecting surface 30, the exit surface 50, the incident surface 40, and the first reflecting surface 20 are all located on the same optical axis Z, which can ensure the symmetry of the overall optical path. The second reflecting surface 30, the exit surface 50, the incident surface 40, and the first reflecting surface 20 can be symmetrically designed with respect to the optical axis Z, or the above-mentioned surfaces can be symmetrically designed with respect to the plane passing through the optical axis Z. The second reflecting surface 30, the exit surface 50, the incident surface 40, and the first reflecting surface 20 are coaxially designed, which can ensure that the entire optical path does not become eccentric (deviate from the optical axis Z, etc.), ensuring clearer imaging and higher imaging quality.

[0047] In some embodiments, refer to Figure 1 , 4And 5, the incident surface 40 and the second reflection surface 30 intersect at a first intersection line 122, and the exit surface 50 and the first reflection surface 20 intersect at a second intersection line 124. Here, the first intersection line 122 and the second intersection line 124 can be understood as the intersection of different surfaces. In the figure, for the convenience of understanding, they are represented by dashed lines. The shape of the intersection line can be determined by the outer contour shapes of the incident surface 40 and the first reflection surface 20, or the shape of the intersection line can be determined by the inner contour shape of the second reflection surface 30 or the inner contour shape of the exit surface 50. For example, the intersection lines 122 and 124 can be a circle, an ellipse, or a polygon, etc. The shapes of the incident surface 40 and the first reflection surface 20 can be a circle, an ellipse, or a polygon, etc. In some embodiments, the distance between the first vertex O2 and the third vertex O4 is not greater than 2.8 mm, that is, the central thickness of the optical module 100. For example, the central thickness along the optical axis Z is not greater than 2.8 mm. For example, it can be 2.8 mm, 2.5 mm, 2 mm, 1.8 mm, 1.6 mm, etc. In some other embodiments, this thickness can also be understood as the average thickness between the exit surface 50 and the incident surface 40, or the average thickness of the entire substrate 10, etc.; the distance of the first intersection line 122 relative to the line connecting the second vertex O3 and the third vertex O4 is not greater than 1.35 mm, that is, the radius of the incident surface 40 is not greater than 1.35 mm. For example, it can be 1.35 mm, 1.2 mm, 1 mm, 0.8 mm, 0.6 mm, etc. The distance of the second intersection line 124 relative to the line connecting the first vertex O2 and the fourth vertex O5 is not greater than 1.5 mm, that is, the radius of the first reflection surface 20 is not greater than 1.5 mm. For example, it can be 1.5 mm, 1.3 mm, 1 mm, 0.85 mm, 0.75 mm, etc. In some embodiments, the respective radii (the vertical distance from the outer contour to the vertex) of the annular side surface 60, the light-emitting surface 50, and the second reflection surface 30 may not be greater than 3 mm, that is, the radius of the annular side surface 60 is not greater than 3 mm, the radius of the light-emitting surface 50 is not greater than 3 mm, and the radius of the second reflection surface 30 is not greater than 3 mm. For example, it can be 3 mm, 2.8 mm, 2.5 mm, 2 mm, etc.; the distance from the second intersection line 124 to the edge of the exit surface 50 can have the same value upward in one week. For example, the width value of the exit surface 50 remains consistent along the circumference of the first reflection surface 20; among them, the distance from the second intersection line 124 to the edge of the exit surface 50 is greater than 0 and less than or equal to 1.6 mm. For example, it can be 1 mm, 1.5 mm, 0.8, 0.7 mm, etc.It can be understood that the above parameters should not be contradictory when combined with each other. The above radius can be the radius parameter when the projected shape of each surface on a certain plane is circular, etc. In some other embodiments, if the projected shape of the above relevant surfaces on a certain plane is not circular, such as a regular polygon, an ellipse or other regular figures, etc., the above radius can also be described as the maximum radius it has. For example, taking an ellipse as an example, its long side can be understood as the radius described above. The size design of the embodiments of the present application can make the entire optical module have a smaller volume and weight, and does not affect the light path transmission efficiency, which is beneficial to the mutual adaptation with the frame or lens of existing near-eye display devices (such as near / far-sighted, eye protection, sports, smart glasses, helmets), and does not require major modification to the structural design of the existing display device, etc., and can realize the compatibility of enhanced display and traditional display devices, improving the portability of the optical module and enriching the application scenarios.

[0048] In some embodiments, as Figure 14 shown, the light from the microdisplay passes through the optical module to form an image 310 from the pupil of the eyeball 300 to the retina for imaging. Figure 14 The positional and structural relationships of the relevant components (such as the eyeball 300, the image 310, etc.) in eye are only exemplary description diagrams for the convenience of calculation and understanding. The following calculation process can be carried out in one dimension, and certain approximations such as small angles are made to illustrate various principles. Among them, the small angle approximation: θ≈sinθ≈tanθ. The above calculations can be directly extended to two dimensions, and more accurate calculations can be carried out. Among them, the field of view FOV (Field Of View) can be finally imaged by the optical module into it. From the retina end, according to the optical expansion amount E

[0049]

[0050] In some embodiments, the lower limit of the field of view FOV can be obtained from the derivation of the above formula {1}:

[0051] Among them,

[0052] Among them, from the optical module end, according to the optical expansion amount E eye Calculation formula:

[0053]

[0054] In some embodiments, the upper limit of the field of view FOV can be obtained from the derivation of the above formula {3}:

[0055]

[0056] In the above formulas, FOV is the field of view, neye is the refractive index of the eyeball, D p is the pupil diameter, θ eye is the light acceptance angle of the point on the retina, I eye is the size of the retinal image 310, D eye is the eyeball diameter, f eye is the focal length of the eyeball, θ m is the effective exit angle of the microdisplay, D m is the maximum outer diameter of the optical module (i.e., the maximum outer diameter among the annular side surface 60, the light exit surface 50, and the second reflecting surface 30), S 1 is the diameter of the incident surface 40 (i.e., twice the distance of the first intersection line 122 relative to the connection line between the second vertex O3 and the third vertex O4), S 2 is the diameter of the first reflecting surface 20 (i.e., twice the distance of the second intersection line 124 relative to the connection line between the first vertex O2 and the fourth vertex O5), L m is the thickness of the substrate 10, which can also be the central thickness of the optical axis or the average thickness of the substrate 10, or the average thickness of the optical path from the microdisplay to the first reflecting surface 20, etc.

[0057] It can be understood that the upper limit value of the field of view angle is often more determined by the parameters of the optical module. In actual design, the size of the optical module is generally restricted relatively strictly (or already fixed), for example, it has a small size and is adapted to traditional head-mounted devices. Therefore, the lower limit value that the field of view angle can meet is often more important and can be designed according to actual needs. In the lower limit formula of the field of view angle FOV, the first term is the double integral of the angle over the size of the imaging image, which exists as an implicit expression in the overall design of the optical module. By designing the incident surface 40 and the light exit surface 50 as non-planar surfaces, where the non-planar surface can be one or a combination of aspherical surfaces, spherical surfaces, and free-form surfaces, the non-planar surface can increase the value of this double integral, thereby increasing the lower limit value (i.e., the minimum value) of the field of view angle of the optical module. It can be seen that when the existing size and related parameters such as the eyeball are limited, it is difficult to change the field of view angle within the limited size. Therefore, in this application, by changing the shapes of the incident surface 40 and the light exit surface 50, the original planar design is changed to a non-planar design, so that the light rays at the relative edge of the microdisplay can enter the first reflecting surface 20 and be projected outside the substrate 10 through the light exit surface 50. In terms of the effect, the light rays from the edge of the microdisplay are more fully utilized, and the projected light rays with a larger included angle can be formed relative to the optical axis Z, thereby forming a larger field of view angle, with better light efficiency and better imaging quality.

[0058] In some embodiments, the aspherical, spherical, and freeform surfaces of the incident surface 40, the first reflecting surface 20, the second reflecting surface 30, and the exit surface 50 can be described by a polynomial sag equation, for example, calculated using Zernike polynomials. The polynomial sag equation can be:

[0059] where

[0060] Z is the surface sag, that is, the distance from the vertex (e.g., s2' in Figure 3 c), h is the radial distance (the distance from the surface to the optical axis, e.g., h2' in 3c), c is the curvature of the surface, k is a coefficient, and A, B, C, and D are the corresponding multi-order coefficients respectively; among them, when k, A, B, C, and D are zero, it can be the sag calculation formula for a spherical surface; as a freeform surface, multiple reference points can be taken to obtain the analytical formula; Figure 3 The contour diagrams of the relevant surfaces are respectively exemplified in Figure 3 (a) is the contour diagram of the incident surface 40, Figure 3 (b) is the contour diagram of the second reflecting surface 30, Figure 3 (c) is the contour diagram of the first reflecting surface 20, Figure 3 (d) is the contour diagram of the exit surface 50; taking Figure 3 the contour diagram of the first reflecting surface 20 in (c) as an example, the first reflecting surface 20 has a vertex 210 and is curved with respect to two orthogonal axes (e.g., the h-Z axis in the figure). The first reflecting surface 20 has at least one first position 212 with a radial distance h1 from the Z axis (optical axis) passing through the vertex 210 and a displacement s1 from the h axis at the vertex 210. Table 1 below exemplarily describes the relevant parameters of each surface (some are exemplarily selected), where h4-Z4 corresponds to the parameters of the incident surface 40, h2-Z2 corresponds to the parameters of the first reflecting surface 20, h3-Z3 corresponds to the parameters of the second reflecting surface 30, and h5-Z5 corresponds to the parameters of the exit surface 50.

[0061] Table 1

[0062] h4 h2 h3 h5 Z4 Z2 Z3 Z5 0.3 0.3 0.3 0.3 0.001774 0.011664 0.007824 0.002036 0.6 0.6 0.6 0.6 0.000062 0.045580 0.031323 0.008255 0.70 0.70 0.70 0.70 -0.005514 0.061351 0.042651 0.011308 0.80 0.80 0.80 0.80 -0.016306 0.079112 0.055734 0.014881 - - 1.2 1.2 - 0.125726 0.034835 - - 1.5 1.5 - 0.196975 0.056573 - - 1.8 1.8 - - 0.284581 0.085106

[0063] In some embodiments, with reference to Figure 6-7, the optical module further includes an outer edge 70 disposed on the annular side surface 60. The height of the outer edge 70 can be higher than that of the annular side surface 60. The circumferential direction of the outer edge 70 can be a complete circle or spaced, etc. The extension of the outer edge 70 in the optical axis Z direction can not exceed the annular side surface 60, that is, the thickness of the outer edge 70 can not exceed the height of the annular side surface 69. Therefore, the outer edge 70 can be a relatively thin protrusion, or the outer edge 70 can also be a thread or other clamping structures, etc. In some embodiments, the outer edge 70 can be located at one end close to the exit surface 50. The outer edge 70 is configured to be assembled with an external mechanism, and the external mechanism can be, for example, a fixture, a jig, etc., so as to facilitate clamping or transporting the optical module and avoid damage to the base 10 or other surfaces. Or the external mechanism can also be a relevant housing to which the optical module needs to be assembled. For example, the corresponding assembly housing is provided with a fixing groove, etc., and the entire optical module can be positioned or fixed through the outer edge 70.

[0064] In some embodiments, referring to Figure 6-7 , the outer edge 70 is further provided with at least one straight edge 72. For example, if the outer edge 70 is circular, the straight edge 72 can be tangent to the outer edge 70. In some other embodiments, two mutually parallel straight edges 72 or more can also be provided on the outer edge 70. Of course, if the outer edge itself can be a polygon, the straight edges of the polygon can be the straight edge 72. The straight edge 72 is configured to cooperate with an external mechanism to position the rotation adjustment of the base 10. It can be understood that the external mechanism can be, for example, a fixture, a jig, etc. The mutually parallel straight edges can better position or clamp the base 10. In other embodiments, the external mechanism can be, for example, an assembly housing. Sometimes it is necessary to rotate the entire optical module in the assembly housing, such as adjusting the light output angle of the optical module, etc. At this time, the straight edge 72 can play a role in anti-fooling, positioning, etc.

[0065] In some embodiments, such as Figure 2 , the optical module may further include a shielding layer 66. The shielding layer 66 covers the annular side surface 60 and is configured to block the light of the microdisplay 80 from being transmitted from the annular side surface 60 to the outside of the base 10. Among them, the shielding layer 66 can be a coating or material such as black epoxy resin, black silicone rubber, carbon black, nickel black, black chromium or vantablack, etc. Of course, it can also be an opaque sealing sleeve, etc. The shielding layer 66 can ensure that the light exits the base 10 from the exit surface 50 instead of leaving from the annular side surface 60, effectively improving the optical efficiency.

[0066] In some embodiments, referring to in combination Figure 9-12, the annular side surface 60 further includes a first toroidal surface 62 and a second toroidal surface 64. The circumferential dimension of the first toroidal surface 62 is smaller than that of the second toroidal surface 64. The first end of the first toroidal surface 62 is connected to the first reflecting surface 20, the second end of the first toroidal surface 62 is connected to the first end of the exit surface 50, the second end of the exit surface 50 is connected to the first end of the second toroidal surface 64, and the second end of the second toroidal surface 64 is connected to the second reflecting surface 30. The first end and the second end of the first toroidal surface 62 are opposite ends, and the first end and the second end of the second toroidal surface 64 are opposite ends. It can be understood that the exit surface 50 is located between the first toroidal surface 62 and the second toroidal surface 64 with different sizes. In some embodiments, the first toroidal surface 62 and the second toroidal surface 64 may have a gradually decreasing trend along the positive direction of the optical axis Z, thereby being able to effectively collect light. It can be understood that since the first toroidal surface 62 and the second toroidal surface 64 have significantly different lateral dimensions to form a stepped structure, the overall size and weight can be further reduced.

[0067] In some embodiments, in combination with Figure 11 , the shielding layer 66 located on the second toroidal surface 64 extends from the edge of the exit surface 50 in a direction away from the exit surface 50, and the end face of the shielding layer 66 located on the second toroidal surface 64 is not higher than the end face of the first reflecting surface 20. The shielding layer 66 located on the second toroidal surface 64 is long enough to prevent light from prematurely entering the outside from the edge of the exit surface 50, and the formation of stray light can also be reduced.

[0068] In some embodiments, such as Figure 13 , the optical module further includes a light extinction wall 90, which can be made of a light-impermeable material (such as the same material as the above-mentioned shielding layer 66) or a material that can block specific wavelengths, etc. The base 10, the first reflecting surface 20, the second reflecting surface 30, and the exit surface 50 each include at least two groups. The light extinction wall 90 is connected between adjacent bases 10, for example, between the annular side surfaces 60 of adjacent optical modules. The light extinction wall 90 is configured to block the light of one base 10 from entering the adjacent other base 10. It can be understood that in two groups of optical modules, the bases 10 are connected into a whole. Each optical module is correspondingly provided with a microdisplay 80, that is, a microdisplay is provided corresponding to a single incident surface. In other embodiments, it can also be that one microdisplay corresponds to multiple incident surfaces 40. The height of the light extinction wall 90 can be greater than or equal to the distance from the second reflecting surface 30 to the exit surface 50, that is, to ensure that the light of adjacent two bases 10 does not interfere with each other, effectively reducing the generation of stray light.

[0069] This application also provides a near-eye display device 200. With reference to Figure 8 、 10 , it includes:

[0070] A microdisplay 80, and

[0071] For the optical module described in the above embodiments, the microdisplay 80 is disposed on the incident surface 40.

[0072] In specific implementation, each of the above units or structures can be implemented as an independent entity, or can be arbitrarily combined and implemented as the same or several entities. For the specific implementation of each of the above units or structures, reference can be made to the previous embodiments, which will not be elaborated here. It can be understood that the near-eye display device 200 may further include, for example, a housing, lenses, a circuit board, a power source, an infrared sensor, a gyroscope, a temperature sensor, etc. The above are not elaborated too much as the components for installation or driving its operation.

[0073] Refer to Figure 15 , this application also provides a processing method for an optical module. The optical module is the optical module described in the above embodiments. The processing method includes the following steps:

[0074] S11. Form a substrate 10; the substrate 10 can be formed by cutting, injection molding, or compression molding.

[0075] S12. Form an exit surface 50 and a first reflecting surface 20 located at the center of the exit surface 50 on the first end 12 of the substrate 10; wherein, the exit surface 50 and the first reflecting surface 20 are one or a combination of a spherical surface, an aspherical surface, and a freeform surface;

[0076] S13. Form an incident surface 40 and a second reflecting surface 30 surrounding the circumference of the incident surface 40 on the second end 14 of the substrate; the incident surface 40 and the second reflecting film 30 are one or a combination of a spherical surface, an aspherical surface, and a freeform surface; the first end and the second end can be opposite ends; it can be understood that the corresponding spherical surface, aspherical surface, and freeform surface can also be formed by, for example, cutting, injection molding, or compression molding, etc.

[0077] S14. Coat a reflecting film on the first reflecting surface 20 and the second reflecting surface 30. The coating can be formed by processes such as evaporation coating or sputtering. The incident surface 40 is configured to receive light from the microdisplay 80. The light enters the substrate 10 through the aspherical incident surface 40, is reflected by the first reflecting surface 20, then is reflected by the second reflecting surface 30, and leaves the substrate 10 through the aspherical exit surface 50. For other descriptions of the optical module, reference can be made to the descriptions of the above embodiments, which will not be elaborated here.

[0078] The above has introduced in detail an optical module, a near-eye display device, and a method for processing an optical module provided by an embodiment of the present application. Specific examples are used in this article to elaborate on the principle and embodiments of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in specific embodiments and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. An optical module is applied to a near-eye display device. It is characterized in that the optical module includes: a substrate (10) including opposite first end (12) and second end (14); a first reflecting surface (20) disposed at the first end (12) of the substrate (10) and configured to allow reflection of light; a second reflecting surface (30) disposed at the second end (14) of the substrate (10) and configured to receive the light reflected from the first reflecting surface (20) and reflect it again; an incident surface (40) disposed at the second end (14) of the substrate (10) and surrounded by the second reflecting surface (30); an exit surface (50) disposed at the first end (12) of the substrate (10) and surrounding the first reflecting surface (20); an annular side surface (60) having one end connected to the second reflecting surface (30) and the other end connected to the exit surface (50); wherein the incident surface (40) and the exit surface (50) are one or a combination of an aspherical surface, a spherical surface, and a free-form surface. The incident surface (40) is configured to receive light from an image of a microdisplay (80). The light enters the substrate (10) through the non-planar incident surface (40), is reflected by the first reflecting surface (20), then reflected by the second reflecting surface (3), and leaves the substrate (10) through the non-planar exit surface (50).

2. The optical module according to claim 1, It is characterized in that the first reflecting surface (20) and the second reflecting surface (30) are one or a combination of an aspherical surface, a spherical surface, and an internal reflecting surface of a free-form surface. Wherein the incident surface (40) includes a first section and a second section from the center to the periphery. The first section is curved in a first direction of the optical axis (Z), and the second section is curved in a second direction opposite to the first direction of the optical axis (Z). The first reflecting surface (20), the second reflecting surface (30), and the exit surface (50) are curved in the first direction of the optical axis (Z).

3. The optical module according to claim 2, It is characterized in that the first reflecting surface (20) includes a first vertex (O2), the second reflecting surface (30) includes a second vertex (O3), the incident surface (40) includes a third vertex (O4), and the exit surface (50) includes a fourth vertex (O5). The first vertex (O2), the second vertex (O3), the third vertex (O4), and the fourth vertex (O5) are located on the optical axis (Z). The incident surface (40), the first reflecting surface (20), the second reflecting surface (30), and the exit surface (50) are symmetrically designed with respect to the cross-section where the optical axis is located.

4. The optical module according to claim 3, It is characterized in that The incident surface (40) and the second reflecting surface (30) intersect at a first intersection line (122), the exit surface (50) and the first reflecting surface (20) intersect at a second intersection line (124), the distance between the first vertex (O2) and the third vertex (O4) is not greater than 2.8 mm, the distance of the first intersection line (122) relative to the line connecting the second vertex (O3) and the third vertex (O4) is not greater than 1.35 mm, and the distance of the second intersection line (124) relative to the line connecting the first vertex (O2) and the fourth vertex (O5) is not greater than 1.5 mm.

5. The optical module according to claim 1, wherein, the radii corresponding to the annular side surface (60), the light-emitting surface (50), and the second reflecting surface (30) are not greater than 3 mm, and the distance from the second intersection line (124) to the edge of the exit surface (50) is greater than 0 and less than or equal to 1.6 mm.

6. The optical module according to claim 1, wherein, the second reflecting surface (30), the exit surface (50), the incident surface (40), and the first reflecting surface (20) have projection profile shapes on a plane perpendicular to the optical axis (Z). The profile shapes of the incident surface (40) and the first reflecting surface (20) are similar shapes to each other, and the profile shapes of the second reflecting surface (30) and the exit surface (50) may be similar shapes to each other.

7. The optical module according to claim 1, wherein, the optical module further includes an outer edge (70). The outer edge (70) is circumferentially provided on the annular side surface (60). The height of the outer edge (70) is higher than that of the annular side surface (60), and the outer edge (70) is configured to be assembled with an external mechanism.

8. The optical module according to claim 7, wherein, the outer edge (70) is further provided with at least one straight edge (72), and the straight edge (72) is configured to cooperate with an external mechanism to position the base body (10).

9. The optical module according to claim 1, wherein, the optical module further includes a shielding layer (66). The shielding layer (66) covers the annular side surface (60) and is configured to block the light of the micro display (80) from being transmitted from the annular side surface (60) to the outside of the base body (10).

10. The optical module according to claim 1, wherein, the annular side surface (60) includes a first toroidal surface (62) and a second toroidal surface (64). The circumferential dimension of the first toroidal surface (62) is smaller than that of the second toroidal surface (64). The first end of the first toroidal surface (62) is connected to the first reflecting surface (20), the second end of the first toroidal surface is connected to the first end of the exit surface (50), the second end of the exit surface (50) is connected to the first end of the second toroidal surface (64), and the second end of the second toroidal surface (64) is connected to the second reflecting surface (30).

11. The optical module according to claim 10, wherein, The shielding layer (66) located on the second toroidal surface (64) extends from the edge of the exit surface (50) in a direction away from the exit surface (50), and the end face of the shielding layer (66) located on the second toroidal surface (64) is not higher than the end face of the first reflecting surface (20).

12. The optical module according to claim 2, wherein, the incident surface (40), the first reflecting surface (20), the second reflecting surface (30), and the exit surface (50) are described by a polynomial sag equation.

13. The optical module according to claim 1, wherein, the field of view angle of the optical module satisfies the formula: Among them, Among them, FOV is the field of view angle, n eye is the refractive index of the eyeball, D p is the aperture diameter of the pupil of the eyeball, θ eye is the light receiving angle of the point on the retina, I eye is the size of the retinal imaging image, D eye is the eyeball diameter, f eye is the focal length of the eyeball, θ m is the effective exit angle of the microdisplay, D m is the maximum outer diameter of the optical module, S 1 is the diameter of the incident surface (40), S 2 is the diameter of the first reflecting surface (20), L m is the thickness of the substrate (10).

14. The optical module according to claim 1, wherein, the optical module further includes: an extinction wall (90), the base body (10), the first reflecting surface (20), the second reflecting surface (30), and the exit surface (50) respectively include at least two groups, the extinction wall (90) is connected between two adjacent base bodies (10) (for example, located between the annular side surfaces (60) of two adjacent optical modules), and the extinction wall (90) is configured to block the light of one of the base bodies (10) from entering the adjacent other base body (10).

15. A near-eye display device, wherein, it includes: a micro display, and an optical module according to any one of claims 1-14, and the micro display (80) is installed on the incident surface (40).

16. A processing method of an optical module, wherein, the optical module is an optical module according to any one of claims 1-14, and the processing method includes the following steps: forming a base body (10); forming an exit surface (50) and a first reflecting surface (20) located at the center of the exit surface (50) on the first end (12) of the base body (10); wherein, the exit surface (50) is one or a combination of an aspherical surface, a spherical surface, and a free-form surface; forming an incident surface (40) and a second reflecting surface (30) surrounding the circumference of the incident surface (40) on the second end (14) of the base body; the incident surface (40) is one or a combination of an aspherical surface, a spherical surface, and a free-form surface; coating a reflective film on the first reflecting surface (20) and the second reflecting surface (30), wherein the incident surface (40) is configured to receive light from the micro display (80) image, the light enters the base body (10) through the aspherical incident surface (40), is reflected by the first reflecting surface (20), then is reflected by the second reflecting surface (3), and leaves the base body (10) through the aspherical exit surface (50).

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