An optical element and a near-eye display system

Abstract

The present invention discloses an optical element and a near-eye display system, relating to the field of display technologies. The optical element of the present invention includes a plurality of first partial reflection surfaces and a plurality of second partial reflection surfaces disposed between a first main outer surface and a second main outer surface that are parallel to each other. A first region and a second region that are connected to each other are defined between the first main outer surface and the second main outer surface along a first direction. The plurality of first partial reflection surfaces are symmetrically distributed in the first region along a second direction perpendicular to the first direction, and planes where adjacent two first partial reflection surfaces are located can intersect. The plurality of second partial reflection surfaces are parallelly distributed in the second region along the first direction. The first partial reflection surfaces are configured to reflect the coupled-in light to the second partial reflection surfaces, and the second partial reflection surfaces are configured to make the coupled-in light exit parallelly from the first main outer surface. The optical element provided by the present invention can improve the light output brightness and uniformity, expand the field of view range, and has high wearability.

Description

Technical Field

[0001] The present invention relates to the field of display technologies, and more particularly, to an optical element and a near-eye display system. Background Art

[0002] In augmented reality technology, a near-eye display system includes a transparent optical waveguide placed in front of a user's eyes. Light is transmitted inside the optical waveguide through internal reflection, and then the image is coupled to the user's eyes through a suitable output mechanism, so as to superimpose a virtual image on the real scene and provide the user with an immersive and interactive experience. Therefore, augmented reality technology has important significance in fields such as entertainment, industry, and medicine.

[0003] In the existing methods for expanding light in two dimensions in an optical waveguide, they are all implemented in the form of a parallel array. In the partial reflection surface technology of the parallel array, when light is totally reflected in the optical waveguide at different angles, for some angles of the totally reflected light, there will be no reflection phenomenon with the partial reflection surface, resulting in the loss of the outgoing light and poor light output uniformity of the optical waveguide, and it is not easy to expand the field of view angle. Summary of the Invention

[0004] The purpose of the present invention is to provide an optical element and a near-eye display system, which can improve the light output uniformity and expand the field of view angle.

[0005] The embodiments of the present invention are implemented as follows:

[0006] An optical element includes a plurality of first partial reflection surfaces and a plurality of second partial reflection surfaces disposed between a first main outer surface and a second main outer surface that are parallel to each other. A first region and a second region that are connected to each other are divided along a first direction between the first main outer surface and the second main outer surface. The plurality of first partial reflection surfaces are symmetrically distributed in the first region along a second direction perpendicular to the first direction, and the planes where two adjacent first partial reflection surfaces are located can intersect. The plurality of second partial reflection surfaces are parallelly distributed in the second region along the first direction. The first partial reflection surfaces are used to reflect the coupled-in light to the second partial reflection surfaces, and the second partial reflection surfaces are used to make the coupled-in light exit parallel to the first main outer surface.

[0007] Optionally, as an implementable manner, the adjacent edges of two adjacent first partial reflection surfaces are connected to each other.

[0008] Optionally, as an implementable manner, the adjacent edges of two adjacent first partial reflection surfaces are separated from each other.

[0009] Optionally, as an implementable manner, a linear polarization film is provided on the first partial reflection surface, and the polarization directions of the plurality of first partial reflection surfaces are alternately perpendicular to each other.

[0010] Optionally, as an implementable manner, the reflectivities of the multiple first partial reflecting surfaces distributed along the second direction increase sequentially, and the reflectivities of the multiple second partial reflecting surfaces distributed along the first direction increase sequentially.

[0011] Optionally, as an implementable manner, the angle α between two adjacent first partial reflecting surfaces satisfies 70° ≤ α ≤ 160°.

[0012] Optionally, as an implementable manner, the angle α1 between the intersection line between the first partial reflecting surface and the first main outer surface and the coupled-in light ray satisfies 25° ≤ α1 ≤ 75°.

[0013] Optionally, as an implementable manner, the angle β between the second partial reflecting surface and the first main outer surface satisfies 20° ≤ β ≤ 45°.

[0014] Optionally, as an implementable manner, the angle β1 between the intersection line between the first partial reflecting surface and the first main outer surface and the intersection line between the second partial reflecting surface and the first main outer surface satisfies 20° ≤ β1 ≤ 65°.

[0015] A near-eye display system includes an optical element as described in any one of the above.

[0016] The beneficial effects of the embodiments of the present invention include:

[0017] The optical element provided by the present invention includes a plurality of first partial reflection surfaces and a plurality of second partial reflection surfaces disposed between a first main outer surface and a second main outer surface that are parallel to each other. A first region and a second region that are connected to each other are defined along a first direction between the first main outer surface and the second main outer surface. The plurality of first partial reflection surfaces are symmetrically distributed in the first region along a second direction perpendicular to the first direction, and the planes where two adjacent first partial reflection surfaces are located can intersect. The plurality of second partial reflection surfaces are parallelly distributed in the second region along the first direction. The first partial reflection surfaces are used to reflect the coupled-in light to the second partial reflection surfaces, and the second partial reflection surfaces are used to make the coupled-in light exit parallelly from the first main outer surface. The above optical element is provided with symmetric and non-parallel first partial reflection surfaces in the first region and parallel second partial reflection surfaces in the second region. After the coupled-in light enters the optical element, total internal reflection occurs between the first main outer surface and the second main outer surface. Between each total internal reflection, the coupled-in light will sequentially undergo partial reflection at the symmetric first partial reflection surfaces as the first-dimensional expansion. After the coupled-in light to be reflected is conducted to the second region, it continues to be conducted and undergo partial reflection in the second partial reflection surfaces that are parallel to each other in the second region as the second-dimensional expansion, and finally the coupled-in light is reflected to the user's eyes. Therefore, the above optical element can improve the light output brightness and uniformity while expanding the user's field of view range, and has a thin and light structure, which is beneficial to system integration and has high wearability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, 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.

[0019] Figure 1 One of the schematic structural diagrams of the optical element provided by the embodiment of the present invention;

[0020] Figure 2 One of the schematic structural diagrams of the first partial reflection surface in the optical element provided by the embodiment of the present invention;

[0021] Figure 3 Another schematic structural diagram of the first partial reflection surface in the optical element provided by the embodiment of the present invention;

[0022] Figure 4 Still another schematic structural diagram of the first partial reflection surface in the optical element provided by the embodiment of the present invention;

[0023] Figure 5 Another schematic structural diagram of the optical element provided by the embodiment of the present invention;

[0024] Figure 6 This is the third schematic structural diagram of the optical element provided by the embodiment of the present invention.

[0025] Icon: 100 - optical element; 110 - first main outer surface; 120 - second main outer surface; 130 - reflection area; 131 - first area; 132 - second area; 140 - first partial reflection surface; 141 - edge of the first partial reflection surface; 150 - second partial reflection surface; 200 - coupled-in light. Detailed implementation manners

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0028] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0029] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention 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 thus cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be construed as indicating or implying relative importance.

[0030] In addition, the terms "horizontal", "vertical", etc. do not mean that the components are required to be absolutely horizontal or hanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0031] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and defined, the terms "arranged", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0032] Please refer to Figure 1 , this embodiment provides an optical element 100, which includes a plurality of first partial reflection surfaces 140 and a plurality of second partial reflection surfaces 150 disposed between mutually parallel first main outer surface 110 and second main outer surface 120. A first region 131 and a second region 132 that are connected to each other are defined in a first direction between the first main outer surface 110 and the second main outer surface 120. The plurality of first partial reflection surfaces 140 are symmetrically distributed in the first region 131 along a second direction perpendicular to the first direction, and planes where adjacent two first partial reflection surfaces 140 are located can intersect. The plurality of second partial reflection surfaces 150 are parallelly distributed in the second region 132 along the first direction. The first partial reflection surfaces 140 are configured to reflect the incident light 200 to the second partial reflection surfaces 150, and the second partial reflection surfaces 150 are configured to make the incident light 200 exit parallelly from the first main outer surface 110.

[0033] The optical element 100 includes a plurality of first partial reflection surfaces 140 and a plurality of second partial reflection surfaces 150 between mutually parallel first main outer surface 110 and second main outer surface 120. A reflection region 130 is formed between the first main outer surface 110 and the second main outer surface 120. The reflection region 130 extends along a first direction ( Figure 1 the A direction in Figure 1 ) and a second direction ( the B direction in

[0034] ), wherein the first direction and the second direction are perpendicular to each other. The reflection region 130 is divided into a mutually connected first region 131 and second region 132 along the first direction. The plurality of first partial reflection surfaces 140 are symmetrically distributed in the first region 131 along the second direction. The plurality of first partial reflection surfaces 140 respectively intersect with the first main outer surface 110 and the second main outer surface 120. Planes where adjacent two first partial reflection surfaces 140 are located have an intersection line (that is, adjacent two first partial reflection surfaces 140 are not parallel to each other), and adjacent two first partial reflection surfaces 140 are symmetric with respect to a plane passing through the intersection line and perpendicular to the first main outer surface 110. The plurality of second partial reflection surfaces 150 are parallelly distributed in the second region 132 along the first direction. The plurality of second partial reflection surfaces 150 respectively intersect with the first main outer surface 110 and the second main outer surface 120.The first partial reflecting surface 140 is located on the first propagation path of the coupled-in light ray 200 and serves as a structure for expanding the coupled-in light ray 200 in the first dimension. After the coupled-in light ray 200 enters the first region 131, total reflection occurs between the parallel first main outer surface 110 and the second main outer surface 120. At the same time, partial reflection occurs on the first partial reflecting surfaces 140 that are symmetric to each other in the first region 131. The second partial reflecting surface 150 is located on the second propagation path of the coupled-in light ray 200 and serves as a structure for expanding the coupled-in light ray 200 in the second dimension. After the reflected coupled-in light ray 200 is conducted to the second region 132, partial reflection continues to occur during conduction within the mutually parallel partial reflecting surfaces, and finally, the coupled-in light ray 200 exits parallel to the first main outer surface 110. The coupled-in light ray 200 that exits parallel will be received by the user's eyes.

[0035] As described above, the optical element 100 includes a plurality of first partial reflecting surfaces 140 and a plurality of second partial reflecting surfaces 150 disposed between the mutually parallel first main outer surface 110 and the second main outer surface 120. The first region 131 and the second region 132 that are connected to each other are divided along the first direction between the first main outer surface 110 and the second main outer surface 120. The plurality of first partial reflecting surfaces 140 are symmetrically distributed in the first region 131 along the second direction perpendicular to the first direction, and the planes where two adjacent first partial reflecting surfaces 140 are located can intersect. The plurality of second partial reflecting surfaces 150 are parallelly distributed in the second region 132 along the first direction. The first partial reflecting surface 140 is used to reflect the coupled-in light ray 200 to the second partial reflecting surface 150, and the second partial reflecting surface 150 is used to make the coupled-in light ray 200 exit parallel to the first main outer surface 110. The above-mentioned optical element 100 is provided with mutually symmetric and non-parallel first partial reflecting surfaces 140 in the first region 131 and mutually parallel second partial reflecting surfaces 150 in the second region 132. After the coupled-in light ray 200 enters the optical element 100, total reflection occurs between the first main outer surface 110 and the second main outer surface 120. Between each total reflection, the coupled-in light ray 200 will sequentially undergo partial reflection on the mutually symmetric first partial reflecting surfaces 140 as the first dimension expansion. After the coupled-in light ray 200 to be reflected is conducted to the second region 132, it continues to sequentially undergo partial reflection during conduction within the mutually parallel second partial reflecting surfaces 150 in the second region 132 as the second dimension expansion, and finally reflects the coupled-in light ray 200 to the user's eyes. Therefore, the above-mentioned optical element 100 can improve the light output brightness and uniformity while expanding the user's field of view range, and has a thin and light structure, which is conducive to system integration and has high wearability.

[0036] Optionally, in an implementable manner of the embodiment of the present invention, both the first partial reflecting surface 140 and the second partial reflecting surface 150 include at least four.

[0037] The number of the first partial reflecting surfaces 140 and the second partial reflecting surfaces 150 is greater than or equal to four, which can better improve the light output brightness and uniformity and expand the viewing field range of the user.

[0038] Please refer to Figure 1 , optionally, in an implementable manner of the embodiment of the present invention, the multiple first partial reflecting surfaces 140 and the multiple second partial reflecting surfaces 150 do not overlap with each other.

[0039] The multiple first partial reflecting surfaces 140 and the multiple second partial reflecting surfaces 150 do not overlap, so as to ensure that the coupled light 200 smoothly enters the second region 132 from the first region 131 and is parallelly emitted from the first main outer surface 110, reduce the loss of the coupled light 200, and improve the light output brightness.

[0040] Please refer to in combination with Figure 2 , optionally, in an implementable manner of the embodiment of the present invention, the adjacent edges of two adjacent first partial reflecting surfaces 140 are connected to each other.

[0041] The multiple first partial reflecting surfaces 140 are sequentially distributed in the first region 131 along the second direction. The intersection line of the first partial reflecting surface 140 and the first main outer surface 110 and the second main outer surface 120 is the edge 141 of the first partial reflecting surface. Each first partial reflecting surface 140 includes two edges in the second direction. The adjacent edges of two adjacent first partial reflecting surfaces 140 are connected to each other, and the multiple first partial reflecting surfaces 140 are connected into a whole.

[0042] Please refer to Figure 1 and Figure 3 , optionally, in an implementable manner of the embodiment of the present invention, the adjacent edges of two adjacent first partial reflecting surfaces 140 are separated from each other.

[0043] The multiple first partial reflecting surfaces 140 are sequentially distributed in the first region 131 along the second direction. The intersection line of the first partial reflecting surface 140 and the first main outer surface 110 and the second main outer surface 120 is the edge 141 of the first partial reflecting surface. Each first partial reflecting surface 140 includes two edges in the second direction. The adjacent edges of two adjacent first partial reflecting surfaces 140 are separated from each other, and more angles of the coupled light 200 can be effectively reflected.

[0044] Please refer to Figure 1 and Figure 4 , optionally, in an implementable manner of the embodiment of the present invention, a linear polarizing film is provided on the first partial reflecting surface 140, and the polarization directions of the multiple first partial reflecting surfaces 140 are perpendicular to each other and alternate.

[0045] A first partial reflecting surface 140 that is symmetric with each other is formed by using a hybrid surface system. By providing a linearly polarized film on the first partial reflecting surface 140, each first partial reflecting surface 140 can only reflect polarized light in one direction. The polarization directions of multiple first partial reflecting surfaces 140 are perpendicular to each other and alternate, that is, along the second direction, multiple first partial reflecting surfaces 140 sequentially reflect S-polarized light - P-polarized light - S-polarized light, and so on, or along the second direction, multiple first partial reflecting surfaces 140 sequentially reflect P-polarized light - S-polarized light - P-polarized light, and so on. For the convenience of description, Figure 4 in the first partial reflecting surface 140 represented by a solid line in Figure 4 reflects polarized light in one direction, and the first partial reflecting surface 140 represented by a dashed line reflects polarized light in another direction. If the first partial reflecting surface 140 represented by a solid line reflects S-polarized light, then the first partial reflecting surface 140 represented by a dashed line reflects P-polarized light; if the first partial reflecting surface 140 represented by a solid line reflects P-polarized light, then the first partial reflecting surface 140 represented by a dashed line reflects S-polarized light. The first partial reflecting surface 140 formed by using the hybrid surface system can improve the light output uniformity and energy transmittance.

[0046] Optionally, in an implementable manner of the embodiment of the present invention, the reflectivities of multiple first partial reflecting surfaces 140 distributed along the second direction increase sequentially, and the reflectivities of multiple second partial reflecting surfaces 150 distributed along the first direction increase sequentially.

[0047] On the propagation path of the coupled light 200, the reflectivities of multiple first partial reflecting surfaces 140 distributed along the second direction increase sequentially, and the reflectivities of multiple second partial reflecting surfaces 150 distributed along the first direction increase sequentially, effectively reducing light loss and improving the light output uniformity. Preferably, on the propagation path of the coupled light 200, the reflectivities of the last first partial reflecting surface 140 and the last second partial reflecting surface 150 are greater than 90%.

[0048] Optionally, in an implementable manner of the embodiment of the present invention, the included angle α between two adjacent first partial reflecting surfaces 140 satisfies 70° ≤ α ≤ 160°.

[0049] When the included angle α between two adjacent first partial reflecting surfaces 140 satisfies 70° ≤ α ≤ 160°, it can ensure that the coupled light 200 smoothly enters the second region 132, and make the coupled light emitted from the first region 131 more uniform, reducing the generation of fringes. Specifically, it can be calculated according to the included angle between the coupled light 200 and the first main outer surface 110 (or the second main outer surface 120), and the included angle α between two adjacent first partial reflecting surfaces 140 can be adjusted.

[0050] Please refer to Figure 1 and Figure 5, Optionally, in an implementable manner of the embodiments of the present invention, the included angle α1 between the intersection line of the first partial reflecting surface 140 and the first main outer surface 110 and the coupled-in light 200 satisfies 25° ≤ α1 ≤ 75°.

[0051] When the included angle α1 between the intersection line of the first partial reflecting surface 140 and the first main outer surface 110 and the coupled-in light 200 satisfies 25° ≤ α1 ≤ 75°, more of the coupled-in light 200 can be reflected into the second region 132, improving the brightness of the coupled-in light emitted from the first region 131, making the emitted light more uniform, and reducing the generation of stripes.

[0052] Please refer to Figure 1 and Figure 6 , Optionally, in an implementable manner of the embodiments of the present invention, the included angle β between the second partial reflecting surface 150 and the first main outer surface 110 satisfies 20° ≤ β ≤ 45°.

[0053] When the included angle β between the second partial reflecting surface 150 and the first main outer surface 110 satisfies 20° ≤ β ≤ 45°, it can ensure that the coupled-in light 200 is emitted parallel from the first main outer surface 110 and can also expand the viewing angle.

[0054] Please refer to Figure 1 and Figure 5 , Optionally, in an implementable manner of the embodiments of the present invention, the included angle β1 between the intersection line of the first partial reflecting surface 140 and the first main outer surface 110 and the intersection line of the second partial reflecting surface 150 and the first main outer surface 110 satisfies 20° ≤ β1 ≤ 65°.

[0055] When the included angle β1 between the intersection line of the first partial reflecting surface 140 and the first main outer surface 110 and the intersection line of the second partial reflecting surface 150 and the first main outer surface 110 satisfies 20° ≤ β1 ≤ 65°, more of the coupled-in light 200 can be emitted from the first main outer surface 110, expanding the viewing angle.

[0056] Optionally, in an implementable manner of the embodiments of the present invention, the viewing angle θ of the user satisfies -40° ≤ θ ≤ 40°.

[0057] When the viewing angle θ of the user satisfies -40° ≤ θ ≤ 40°, the user can receive a clear and complete image within a relatively large viewing range, which is beneficial to improving the wearability of the optical element 100.

[0058] The embodiments of the present invention also disclose a near-eye display system, which includes the optical element 100 as described in any one of the above.

[0059] This near-eye display system includes the same structure and beneficial effects as the optical element 100 in the foregoing embodiments. The structure and beneficial effects of the optical element 100 have been described in detail in the foregoing embodiments and will not be elaborated herein.

[0060] The foregoing are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An optical element, characterized in that, It includes a plurality of first partial reflecting surfaces and a plurality of second partial reflecting surfaces disposed between a first main outer surface and a second main outer surface that are parallel to each other. There are a first region and a second region that are connected to each other between the first main outer surface and the second main outer surface along a first direction. The plurality of first partial reflecting surfaces are symmetrically distributed in the first region along a second direction perpendicular to the first direction, and the planes where two adjacent first partial reflecting surfaces are located intersect. The intersection line of the planes where two adjacent first partial reflecting surfaces are located is on the first main outer surface or parallel to the first main outer surface. The plurality of second partial reflecting surfaces are parallelly distributed in the second region along the first direction. The first partial reflecting surfaces are used to reflect the coupled-in light to the second partial reflecting surfaces, and the second partial reflecting surfaces are used to make the coupled-in light exit parallelly from the first main outer surface.

2. The optical element according to claim 1, characterized in that, The adjacent edges of two adjacent first partial reflecting surfaces are connected to each other.

3. The optical element according to claim 1, wherein The adjacent edges of two adjacent first partial reflecting surfaces are separated from each other.

4. The optical element according to claim 1, characterized in that, A linear polarization film is provided on the first partial reflecting surfaces, and the polarization directions of the plurality of first partial reflecting surfaces are perpendicular to each other and alternate.

5. The optical element according to claim 1, characterized in that, The reflectivities of the plurality of first partial reflecting surfaces distributed along the second direction increase sequentially, and the reflectivities of the plurality of second partial reflecting surfaces distributed along the first direction increase sequentially.

6. The optical element according to any one of claims 1 to 5, characterized in that, The included angle α between two adjacent first partial reflecting surfaces satisfies 70° ≤ α ≤ 160°.

7. The optical element according to any one of claims 1 to 5, characterized in that The included angle α1 between the intersection line between the first partial reflecting surface and the first main outer surface and the coupled-in light satisfies 25° ≤ α1 ≤ 75°.

8. The optical element according to any one of claims 1 to 5, characterized in that The included angle β between the second partial reflecting surface and the first main outer surface satisfies 20° ≤ β ≤ 45°.

9. The optical element according to any one of claims 1 to 5, characterized in that, The included angle β1 between the intersection line between the first partial reflecting surface and the first main outer surface and the intersection line between the second partial reflecting surface and the first main outer surface satisfies 20° ≤ β1 ≤ 65°.

10. A near-eye display system, characterized in that, It includes an optical element according to any one of claims 1 to 9.

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