Optical display assembly and near-to-eye display equipment

Abstract

The invention relates to the technical field of optical display, particularly provides an optical display assembly and near-to-eye display equipment, and aims to solve the problem that the existing near-to-eye display equipment cannot ensure that eyebox is expanded at a relatively large field angle. In order to achieve the purpose, the optical display assembly comprises a transmission unit, a curved surface element and a plane element, incident light is refracted to the plane element through the transmission unit, reflected to the curved surface element through the plane element, reflected by the curved surface element and then transmitted through the plane element for imaging display. Wherein the transmission unit comprises at least one transmission element, at least one transmission element in the at least one transmission element comprises a first surface and a second surface, the first surface and the second surface are sequentially arranged in the transmission direction of incident light, and the first surface and / or the second surface are / is aspheric surfaces. The first surface and / or the second surface are / is aspheric, so that the imaging quality can be effectively improved, and the size of the eyebox can be enlarged.

Description

Technical Field

[0001] This application relates to the field of optical display technologies, and particularly provides an optical display component and a near-eye display device. Background Art

[0002] A near-eye display device can magnify an image on a display screen through an optical display component, transmit the image to a human eye, and thus present a large-screen image to a viewer. In related technologies, an augmented reality type of near-eye display device can enable a viewer to simultaneously see the image on the display screen and the external environment. However, in the case of a large field of view angle, the eyebox (indicating the area where the human eye can clearly see the entire virtual image) is small, and it is impossible to ensure an enlarged eyebox at a large field of view angle, which affects the user experience. Summary of the Invention

[0003] This application aims to solve the above technical problems, that is, to solve the problem that existing near-eye display devices cannot ensure an enlarged eyebox at a large field of view angle.

[0004] In a first aspect, this application provides an optical display component, which includes: a transmission unit, a planar element, and a curved surface element; incident light is refracted by the transmission unit to the planar element, reflected by the planar element to the curved surface element, and after being reflected by the curved surface element, passes through the planar element for imaging display;

[0005] Wherein, the transmission unit includes at least one transmission element, and at least one of the at least one transmission element includes a first surface and a second surface sequentially arranged along the transmission direction of the incident light, and the first surface and / or the second surface is an aspherical surface.

[0006] In some embodiments, when the transmission unit includes one transmission element, the first surface is an aspherical surface with a paraxial curvature radius greater than 0.

[0007] In some embodiments, the difference between the curvature radius at a position with a first preset distance from the center on the first surface and the curvature radius at a position with a second preset distance is greater than or equal to 5 millimeters.

[0008] In some embodiments, the second surface is an aspherical surface with a paraxial curvature radius greater than 0, and the paraxial curvature radius of the second surface is smaller than the paraxial curvature radius of the first surface.

[0009] In some embodiments, the angle between the tangent at any point on the second surface and the optical axis direction of the transmission element is greater than 0° and less than 55°.

[0010] In some embodiments, the transmission unit includes a convex lens and a concave-convex lens sequentially arranged along the transmission direction of the incident light.

[0011] In some embodiments, the first surface and / or the second surface are even aspherical surfaces.

[0012] In some embodiments, the first surface and / or the second surface are even aspherical surfaces with an aspherical coefficient up to the 10th or 12th order.

[0013] In some embodiments, the curved surface element includes an even aspherical reflecting surface.

[0014] In a second aspect, the present application provides a near-eye display device, which includes a display and the optical display component described in any one of the above; the optical display component is arranged in the light-emitting direction of the display.

[0015] In the case of adopting the above technical solutions, the present application can provide an optical display component, which includes a transmission unit, a curved surface element and a planar element; incident light is refracted by the transmission unit to the planar element, reflected by the planar element to the curved surface element, and after being reflected by the curved surface element, passes through the planar element for imaging display. Among them, the transmission unit includes at least one transmission element, and at least one of the at least one transmission element includes a first surface and a second surface sequentially arranged along the transmission direction of the incident light, and the first surface and / or the second surface are aspherical surfaces. By setting the first surface and / or the second surface as aspherical surfaces, the imaging quality can be effectively improved and the size of the eyebox can be enlarged. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The preferred embodiments of the present application will be described below with reference to the accompanying drawings, in which:

[0017] Figure 1 is a schematic structural diagram of a light display component provided by an embodiment of the present application;

[0018] Figure 2 is a schematic structural diagram of an optical display component provided by an embodiment of the present application with one transmission element;

[0019] Figure 3 is a schematic structural diagram of an optical display component provided by an embodiment of the present application with two transmission elements;

[0020] Figure 4 is a schematic structural diagram of a near-eye display device provided by an embodiment of the present application;

[0021] Figure 5 is a schematic MTF diagram of the near-eye display device provided by an example of the present application under different fields of view. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this application. Apparently, the described embodiments are only a part rather than all of the embodiments disclosed in this application. Based on the described embodiments disclosed in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0023] Unless otherwise defined, the technical terms or scientific terms used in this application shall have the ordinary meanings as understood by those of ordinary skill in the art to which this application belongs. The terms "first", "second", and similar terms used in this application do not denote any order, quantity, or importance, but are only used to distinguish different components. The terms "including" or "comprising" and the like mean that the elements or items appearing before this word cover the elements or items listed after this word and their equivalents, without excluding other elements or items. The terms "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0024] See Figure 1 as shown Figure 1 is a schematic structural diagram of a light display component provided by an embodiment of this application, which may include:

[0025] a transmission unit 11, a planar element 12, and a curved surface element 13; the incident light is refracted by the transmission unit 11 to the planar element 12, reflected by the planar element 12 to the curved surface element 13, and then reflected by the curved surface element 13 and transmitted through the planar element 12 for imaging display;

[0026] Among them, the transmission unit 11 includes at least one transmission element, and at least one of the at least one transmission element includes a first surface and a second surface sequentially arranged along the transmission direction of the incident light, and the first surface and / or the second surface is an aspherical surface.

[0027] By setting the first surface and / or the second surface of the transmission element as an aspherical surface, the surface shape parameters at different apertures of the aspherical surface are different, and the degree of optimization is higher, which can better control the direction and distribution of light, realize aberration correction, enable more light to be used for imaging display, thereby providing a clearer image, a wider field of view, and expanding the size of the eyebox.

[0028] In some embodiments, when only one of the first surface and the second surface is an aspherical surface, the other can adopt the conventional settings in the art, such as a spherical surface.

[0029] In some embodiments, when both the first surface and the second surface are aspherical surfaces, the surface shape parameters of the first surface and the second surface may also be different, where the surface shape parameters include at least one of the radius of curvature, the aspherical coefficient, and the conic coefficient.

[0030] In some embodiments, the first surface and / or the second surface may be an even-order aspherical surface.

[0031] In some preferred embodiments, the first surface and / or the second surface may be an even-order aspherical surface with an aspherical coefficient up to the 10th or 12th order. By setting the first surface and / or the second surface as a higher-order even-order aspherical surface, the design freedom of the transmission element is greater, which is beneficial to better correcting the aberration and improving the imaging quality.

[0032] In some embodiments, as shown in Figure 1 the plane element 12 may be at an angle of 45° with respect to the direction of the dashed line L1 shown in Figure 1 ; in some preferred embodiments, in order to improve the imaging quality, the plane element 12 may be at an angle of 46° with respect to the vertical direction, and the vertical direction is the direction perpendicular to the direction of the dashed line L1.

[0033] In some embodiments, in order to improve the imaging quality, the curved surface element 13 may include an even-order aspherical reflecting surface. Wherein, the reflecting surface is the surface of the curved surface element 13 opposite to the plane element 12.

[0034] In some embodiments, a polarization film is attached to the inner surface of the plane element 12, a semi-transmissive and semi-reflective film is coated on the curved surface element 13 (as an example, the semi-transmissive and semi-reflective film may adopt a film layer with a transmittance of 60% and a reflectance of 40%), in addition, a layer of QWP (Quarter-Wave Plate) is attached to each side of the curved surface element 13, the fast axis angles of the QWPs are orthogonal to each other, and a reflective polarizer is attached between the outer QWP and the cover glass. The light emitted from the display is polarized light as the input light, which is refracted by the transmission unit 11 and reflected to the curved surface element 13 after passing through the reflective polarizer on the plane element 12. Part of the light becomes circularly polarized light after passing through the QWP inside the curved surface element 13 and is reflected by the curved surface element 13, and after the polarization state is changed, it passes through the plane element 12 and reaches the human eye. Another part of the light passes through the curved surface element 13, becomes linearly polarized light again after passing through the QWP, and is reflected back after reaching the reflective polarizer. By setting such a film layer structure, 95% of the light leakage can be effectively blocked. At the same time, the external natural light becomes polarized light after passing through the curved surface element 13, and the polarization direction is consistent with the property of the polarizer attached to the plane element 12, so it can be transmitted into the human eye.

[0035] In some embodiments, the transmission unit 11 may include a transmission element 111, as shown in Figure 2 described above. Figure 2It is a schematic structural diagram of an optical display component provided with a transmissive element according to an embodiment of the present application.

[0036] In some embodiments, the first surface S1 of the transmissive element 111 may be an aspherical surface with a paraxial curvature radius greater than 0. Among them, the larger the paraxial curvature radius of the first surface S1, the more beneficial it is to improve the imaging quality of the optical display component.

[0037] In some embodiments, when the first surface S1 is an aspherical surface with a paraxial curvature radius greater than 0, the difference between the curvature radius at a position on the first surface S1 at a first preset distance from the center and the curvature radius at a second preset distance position may be at least 5 mm.

[0038] Among them, the first preset distance position and the second preset distance position may be two different positions close to the edge of the first surface S1, and can be flexibly set according to the actual size of the first surface S1. As an example, the first preset distance position may be a position 7 mm away from the center of the first surface S1, and the second preset distance position may be a position 7.5 mm away from the center of the first surface S1. By setting the difference between the curvature radius at a position on the first surface S1 at a first preset distance from the center and the curvature radius at a second preset distance position to be greater than or equal to 5 mm, the lens position changes accordingly, thereby avoiding the interference of marginal rays with the optical element and causing a decrease in imaging quality.

[0039] In some embodiments, the first surface S1 may be an even-order aspherical surface with a paraxial curvature radius greater than 0.

[0040] In some preferred embodiments, the first surface S1 may be an even-order aspherical surface with an aspherical coefficient reaching the 10th or 12th order and a paraxial curvature radius greater than 0.

[0041] In some embodiments, the second surface S2 may be an aspherical surface with a paraxial curvature radius greater than 0, and the paraxial curvature radius of the second surface is less than the paraxial curvature radius of the first surface.

[0042] In some embodiments, the second surface S2 may be an even-order aspherical surface with a paraxial curvature radius greater than 0, and the paraxial curvature radius of the second surface is less than the paraxial curvature radius of the first surface.

[0043] In some preferred embodiments, the second surface S2 may be an even-order aspherical surface with an aspherical coefficient reaching the 10th or 12th order, a paraxial curvature radius greater than 0, and the paraxial curvature radius of the second surface is less than the paraxial curvature radius of the first surface.

[0044] It should be noted that the curvature radius and the even-order aspherical coefficient of the second surface S2 may be different from those of the first surface S1.

[0045] In some embodiments, the angle between the tangent line at any point on the second surface S2 and the optical axis direction of the transmission element is greater than 0° and less than 55°.

[0046] Among them, the angle between the tangent line at the point near the center of the second surface S2 and the optical axis direction of the transmission element is relatively small, and the angle between the tangent line at the point near the edge of the surface and the optical axis direction is relatively large and less than 55°. This ensures that the light passing through the center of the surface is relatively gentle and the edge thickness of the transmission element is not too small, facilitating processing.

[0047] In some embodiments, by adjusting the even aspherical coefficient of the second surface S2, the angles between the tangent lines at multiple points from the center to the edge on the second surface S2 and the optical axis direction of the transmission element can be set to show a monotonically increasing trend, so as to reduce the inflection points of sudden curvature change and facilitate processing.

[0048] In some embodiments, the transmission unit 11 may include multiple transmission elements. Among them, at least one transmission element includes a first surface and a second surface sequentially arranged along the incident light transmission direction, and the first surface and / or the second surface is an aspherical surface.

[0049] In some embodiments, referring to Figure 3 as shown in Figure 3 is a schematic structural diagram of an optical display component provided with two transmission elements according to an embodiment of the present application.

[0050] The transmission unit 11 may include a convex lens 112 and a concave-convex lens 113 sequentially arranged along the incident light transmission direction. Among them, at least one of the convex lens 112 and the concave-convex lens may be provided with an aspherical surface.

[0051] In some embodiments, the convex lens 112 may include a first surface B1 and a second surface B2 sequentially arranged along the incident light transmission direction, and the first surface B1 and / or the second surface B2 may be an aspherical surface. The convex lens 112 may be referred to as an aspherical convex lens.

[0052] In some embodiments, the first surface B1 and / or the second surface B2 may be an even aspherical surface.

[0053] In some embodiments, the first surface B1 and / or the second surface B2 may be an even aspherical surface with an aspherical coefficient reaching the 10th or 12th order.

[0054] It should be noted that the surface shape parameters of the first surface B1 and the second surface B2 may be different.

[0055] In some embodiments, the concave-convex lens 113 may include a first surface C1 and a second surface C2 sequentially arranged along the incident light transmission direction, and the first surface C1 and / or the second surface C2 may be an aspherical surface. The concave-convex lens 113 may be referred to as an aspherical concave-convex lens.

[0056] In some embodiments, the first surface C1 and / or the second surface C2 may be an even-order aspherical surface.

[0057] In some embodiments, the first surface C1 and / or the second surface C2 may be an even-order aspherical surface with an aspherical coefficient up to the 10th or 12th order.

[0058] It should be noted that the surface shape parameters of the first surface C1 and the second surface C2 may be different.

[0059] In the embodiments of the present application, by setting the transmission unit 11 to include a plurality of transmission elements and at least one transmission element includes an aspherical surface, the imaging quality can be effectively improved and the eyebox size can be enlarged. In addition, compared with only setting one transmission element, by setting a plurality of transmission elements, the surface of the transmission elements and the air gap that can be optimized are increased, which is beneficial to increasing the optimization freedom and further improving the image imaging quality.

[0060] It should be noted that in other embodiments, the transmission element may also adopt a lens with other surface shape structures, and the transmission unit 11 can be obtained through lenses with different surface shape structures.

[0061] On the other hand, the present application provides a near-eye display device. Refer to Figure 4 as shown Figure 4 is a schematic structural diagram of the near-eye display device provided by the embodiments of the present application, which may include:

[0062] A display 41, such as the optical display component described in any of the above embodiments, is arranged in the light output direction of the display.

[0063] Among them, the near-eye display device may be an enhanced display type near-eye display device.

[0064] In some embodiments, the display 41 may adopt a micro display. As an example, the micro display may adopt a Micro OLED (Micro Organic Light Emitting Diode, micro organic light emitting display), which can meet the requirements of high-brightness display and improve the image quality and user experience.

[0065] As an example, the near-eye display device may include a diaphragm arranged at the position for human eyes to view. When using Figure 2For the optical display component shown, when the display 41 uses a 0.71-inch flat surface, by adjusting the focal lengths, relative distances, and surface shape parameters of the curved surface element 13 and the transmissive element 111, it is possible to ensure a field of view FOV = 46°, while simultaneously satisfying an exit pupil distance ERF > 13 mm, Eyebox = 10 * 8 mm, and MTF > 0.15 @ 32.77 lp / mm, achieving an enlarged eyebox size, a longer exit pupil distance, and better imaging quality.

[0066] Among them, MTF (Modulation Transfer Function) is the abbreviation of the modulation transfer function, which is used to describe the resolution and contrast capabilities of an imaging system. 0.15 @ 32.77 lp / mm means that at 32.77 line pairs per millimeter, the contrast of this display device is greater than 0.15.

[0067] The relative distance can include the distance between the aperture and the curved surface element 13, the distance between the curved surface element 13 and the planar element 12, the distance between the planar element 12 and the second surface S2 of the transmissive element 111, the distance between the second surface S2 and the first surface S1 of the transmissive element 111, and the distance between the first surface S1 and the display 40.

[0068] Among them, the focal lengths, relative distances, and surface shape parameters of the curved surface element 13 and the transmissive element 111 can adopt the data shown in Table 1 and Table 2 below. The relative distance is represented by thickness in Table 1.

[0069] Table 1 is the parameter data table of the near-eye display device.

[0070] Table 2 is the aspherical coefficient table of the even aspheres. Parameter term 12 S2 S1 Second-order term 0 0 0 Fourth-order term 1.82E-6 -4.11E-4 -6.03E-3 Sixth-order term 8.35E-9 1.17E-5 2.57E-4 Eighth-order term -2.50E-11 -3.37E-7 -4.73E-6 Tenth-order term 5.64E-14 5.65E-9 3.95E-8 Twelfth-order term -3.27E-17 -2.96E-11 -1.24E-10

[0071] As can be seen from Table 1 above, parameters such as refractive index, property, X eccentricity, Y eccentricity, Alpha eccentricity, and Abbe number can also be set.

[0072] See Figure 5 as shown Figure 5It is a schematic diagram of MTF at different fields of view of the near-eye display device provided by the example of this application. Among them, multiple curves respectively correspond to different viewing angles in the X direction and the Y direction. Among them, the solid line represents the meridional MTF, and the dashed line represents the sagittal MTF. The abscissa in the figure is the spatial frequency: cycles / mm, and the ordinate is the modulus value of the OTF. OTF (Optical Transfer Function) is the abbreviation of the optical transfer function, which describes the response and resolution of the imaging system in the spatial frequency range. It can be seen from the figure that the cut-off frequencies corresponding to each curve are all greater than 0.15. Among them, 0.15 is based on a display screen with 0.71 inches, 1920*1080 pixels, and a pixel pitch of 8.19 μm, as well as a display screen with 0.68 inches and a pixel pitch of 7.63 μm that needs to be compatible. When calculated by the requirement of 2PPL (lines per millimeter), it corresponds to 32.77 lp / mm, and the obtained value can meet the imaging quality requirements. That is, the near-eye display device provided by the example of this application can ensure the imaging quality.

[0073] So far, the technical solution of this application has been described in combination with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of this application is obviously not limited to these specific embodiments. Without departing from the principle of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this application.

Claims

1. An optical display component, characterized in that, Comprising: A transmission unit, a planar element, and a curved surface element; incident light is refracted by the transmission unit to the planar element, reflected by the planar element to the curved surface element, and after being reflected by the curved surface element, passes through the planar element for imaging display; Wherein, the transmission unit includes at least one transmission element, and at least one of the at least one transmission element includes a first surface and a second surface sequentially arranged along the transmission direction of the incident light, and the first surface and / or the second surface is an aspherical surface.

2. The optical display component according to claim 1, wherein When the transmission unit includes one transmission element, the first surface is an aspherical surface with a paraxial curvature radius greater than 0.

3. The optical display component according to claim 2, wherein, The difference between the curvature radius at a position on the first surface at a first preset distance from the center and the curvature radius at a second preset distance position is greater than or equal to 5 millimeters.

4. The optical display component according to claim 1, wherein The second surface is an aspherical surface with a paraxial curvature radius greater than 0, and the paraxial curvature radius of the second surface is less than the paraxial curvature radius of the first surface.

5. The optical display component according to claim 4, characterized in that, The angle between the tangent at any point on the second surface and the optical axis direction of the transmission element is greater than 0° and less than 55°.

6. The optical display component according to claim 1, wherein The transmission unit includes a convex lens and a convex-concave lens sequentially arranged along the transmission direction of the incident light.

7. The optical display component according to any one of claims 1 to 6, characterized in that, The first surface and / or the second surface is an even aspherical surface.

8. The optical display component according to claim 7, wherein, The first surface and / or the second surface is an even aspherical surface with an aspherical coefficient reaching the 10th or 12th order.

9. The optical display component according to claim 1, wherein The curved surface element includes an even aspherical reflecting surface.

10. A near-eye display device, characterized in that, Comprising a display and the optical display assembly according to any one of claims 1 to 9; the optical display assembly is arranged in the light-emitting direction of the display.

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