Dual-screen display optical device and head-mounted display device

Abstract

The present invention relates to the technical field of head-mounted display devices, and in particular to a dual-screen display optical device and a head-mounted display device equipped with the optical device. The dual-screen display optical device includes an optical component, a first display screen arranged above the optical component, and a second display screen arranged in front of the optical component. The optical component includes a first lens group, a second lens group, and a waveguide lens group arranged in sequence front to back. The image light of the first display screen enters the human eye after being reflected and / or refracted by the waveguide lens group and the second lens group; the image light of the second display screen enters the human eye after being reflected and / or refracted by the first lens group, the second lens group, and the waveguide lens group. The present invention provides two display screens, each of which presents different images in the human eye through the optical component, and by configuring the optical component and adjusting the imaging focal length, image effects with different depths of field can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of head-mounted display devices, and in particular to a dual-screen display optical device and a head-mounted display device equipped with the optical device. Background Art

[0002] In the field of virtual reality, head-mounted display devices, such as VR glasses and AR glasses, are essential components. These devices use a set of optical components to project images from a small display onto the human retina, creating the illusion of viewing a large screen. Existing head-mounted display devices often use a single display, allowing users to see images with only a single depth of field, and with identical resolution at the center and edges of the field of view. However, wide-angle headsets require very high resolution in the center, while only requiring low resolution at the edges.

[0003] Currently, to address the issue of a single depth of field for head-mounted display devices, a patent document (CN209417426U) discloses VR glasses with dual independent, adjustable display screens. By independently providing adjustable eyepieces and display screens for the left and right eyes, the glasses can focus on each eye separately. However, this approach does not address the issue of multiple depths of field. Furthermore, since the two displays have the same field of view, it cannot achieve the effect of fusion and superposition of images from multiple angles of view. It also cannot address the issue of different resolution requirements for the center and edge areas of a wide field of view. Summary of the Invention

[0004] To solve the above problems, the present invention provides a dual-screen display optical device, which achieves the effect of fusion and superposition of images with multiple field of view angles by setting up two display screens, one large and one small, and can simultaneously display images with multiple depths of field.

[0005] A dual-screen display optical device includes an optical assembly, a first display screen disposed above the optical assembly, and a second display screen disposed in front of the optical assembly. The optical assembly includes a first lens group, a second lens group, and a waveguide lens group arranged in a front-to-back order. Image light from the first display screen enters the human eye after being reflected and / or refracted by the waveguide lens group and the second lens group; image light from the second display screen enters the human eye after being reflected and / or refracted by the first lens group, the second lens group, and the waveguide lens group. The present invention arranges two display screens in front of and above the optical assembly, and selects appropriate optical components to ensure that the images from the two display screens enter the human eye after being reflected and refracted, forming a magnified image in the human eye, thereby achieving fusion and superposition of the two images.

[0006] The first and second displays can have the same or different resolutions, the same or different viewing angles, and the same or different optical axes. The virtual images formed in the human eye may or may not overlap, but the content must always match for splicing. Specifically, after the images of the first and second displays are reflected and / or refracted by the optical component, they are superimposed at the human eye, with the displayed content matching each other and the displayed images located on the same plane or on different planes.

[0007] Furthermore, the first lens group includes a first lens and a first partial reflector, the first lens is a curved lens with uniform thickness, the first lens includes a convex surface and a concave surface, the convex surface is close to the second display screen, and the concave surface is close to the second lens group, and the first partial reflector is arranged on the concave surface of the first lens. The second lens group includes a second lens and a second partial reflector, the second lens is a curved lens with uniform thickness, the second lens includes a convex surface and a concave surface, the convex surface is close to the first lens group, and the concave surface is close to the waveguide lens group, and the second partial reflector is arranged on the convex surface of the second lens. The first lens and the second lens are configured to have uniform thickness, so that the image light will not be distorted during perspective. At the same time, by combining the concave reflective surface and the convex reflective surface and providing a partial reflector, the requirements for transmission and reflection magnification imaging of light from different directions can be met.

[0008] The waveguide lens assembly includes a waveguide prism, a waveguide compensator, and a third partial reflector. The waveguide prism is positioned adjacent to the first display screen, while the waveguide compensator is positioned below the waveguide prism. The waveguide prism and the waveguide compensator are bonded together along an inclined surface to form a uniformly thick optical lens. The third partial reflector is positioned between the waveguide prism and the waveguide compensator. The function of the waveguide prism is to achieve multiple reflections of light within the prism. To prevent light from reflecting within the prism and allowing it to exit the prism for the next lens, the present invention incorporates a partial reflector on the rear side of the waveguide prism. Furthermore, the waveguide compensator ensures uniform lens thickness without visual distortion.

[0009] The first, second and third partial reflectors partially transmit and partially reflect light, and the first, second and third partial reflectors are semi-transmissive and semi-reflective films or reflective polarizing films.

[0010] To achieve high resolution at a narrow central field of view and low resolution at a wide peripheral field of view, the image display area of ​​the first display can be smaller than that of the second display, while the resolution of the first display can be greater than that of the second display. This allows for a differentiated display effect with different resolutions on both screens at the same focal length.

[0011] In addition to enabling the superposition of images of the same depth of field, different resolutions, and different sizes, the present invention can also display images of different depths of field (i.e., dual-screen images displayed front and back). This can be achieved by setting the focal lengths of the two display screens through the optical components to be different. Specifically, the following two solutions can be adopted:

[0012] 1. The second lens group can move back and forth to adjust the position of the images of the first display screen and the second display screen in the human eye after passing through the optical component, so as to achieve a display effect in which the images of the first display screen and the second display screen are in the same focal plane at the human eye or have a greater depth of field contrast.

[0013] 2. The first display screen is movable. When the first display screen is moved, the imaging focal length of the first display screen at the human eye through the optical component changes.

[0014] Furthermore, the first lens assembly further includes a first quarter glass disposed behind the first lens, and / or the second lens assembly further includes a second quarter glass disposed behind the second lens. The quarter glass serves to correct the light reflected from the lens to prevent image distortion. Without the quarter glass, the image may have double images.

[0015] In addition to providing an optical channel for images on the first and second displays, the present invention can also provide an optical channel for the external environment. Specifically, the second display is configured as a rotating scanning screen, allowing ambient light to pass through the display and optical components and enter the human eye, enabling simultaneous display of the second display image and the external environment image.

[0016] A head-mounted display device comprises the above-mentioned dual-screen display optical device.

[0017] Beneficial effects of the present invention:

[0018] 1. The present invention provides two display screens, each of which presents different images to the human eye through optical components. Furthermore, by configuring the optical components and adjusting the imaging focal length, image effects with different depths of field can be achieved.

[0019] 2. The present invention can achieve the requirements of high resolution in the center area with a large field of view and low resolution in the edge area by setting different field of view angles and resolutions for the two display screens. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the optical structure of Example 1;

[0021] Figure 2 is a schematic diagram of the optical structure of Example 2;

[0022] Figure 3 This is a schematic diagram of an imaging effect of Example 3;

[0023] Figure 4 is another schematic diagram of imaging effect of Example 3;

[0024] Figure 5 Schematic diagram of the imaging effect of Example 4;

[0025] Figure 6 is a schematic diagram of the optical structure of Example 5;

[0026] Figure 7 This is a schematic diagram of the rotating scanning screen in Example 5.

[0027] In the figure, 1, second display screen, 2, first lens, 3, second lens, 4, waveguide prism, 5, first display screen, 6, first partial reflector, 7, second partial reflector, 8, waveguide compensation mirror, 9, human eye, 10, third partial reflector, 11, 1 / 4 glass slide. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are described in detail below with reference to the accompanying drawings and examples.

[0029] Example 1

[0030] A dual-screen display optical device, such as Figure 1As shown, the optical assembly includes an optical component, a first display screen 5, and a second display screen 1. The optical component includes a first lens group, a second lens group, and a waveguide lens group. The first lens group is located at the front and includes a first lens 2 and a first partial reflector 6. The first lens 2 is a curved lens with uniform thickness, including a convex surface and a concave surface, wherein the convex surface is close to the first display screen and the concave surface is close to the second lens group. The first partial reflector 6 is made of a semi-transparent semi-reflective film or a reflective polarizing film, which is applied / plated on the concave surface to form a concave reflective surface for magnifying the image. The second lens group is located in the middle and includes a second lens 3 and a second partial reflector 7. The second lens 3 is a curved lens with uniform thickness, including a convex surface and a concave surface, wherein the convex surface is close to the first lens group and the concave surface is close to the waveguide lens group. The second partial reflector 7 is made of a semi-transparent semi-reflective film or a reflective polarizing film, which is applied / plated on the convex surface to form a convex reflective surface for reducing the image. The waveguide lens assembly is located on the rear side and includes a waveguide prism 4 and a waveguide compensator 8. The waveguide prism 4 has a triangular cross-section, with a vertical front side and inclined top and rear sides. The front and top sides of the waveguide prism 4 are coated with a waveguide film for light reflection. The waveguide compensator 8 has an inclined surface at the same angle as the rear side of the waveguide prism, and its front and rear sides are vertically parallel. The waveguide compensator 8 is located below the waveguide prism 4. A third partial reflector 10 is located at the interface between the two. The third partial reflector 10 can be a semi-transparent semi-reflective film or a reflective polarizing film. The waveguide prism and the waveguide compensator are then bonded together to form a lens with uniform thickness. The semi-transparent semi-reflective film at the interface reflects light transmitted from the waveguide prism out of the waveguide prism and toward the second lens.

[0031] The first display screen 5 is located above the waveguide prism 4 and is placed parallel to the top surface of the waveguide prism. The second display screen 1 is located in front of the first lens group and is placed parallel to the waveguide prism group. The dual-screen display device is installed on a head-mounted display device for application.

[0032] The transmission path of light from the first display screen is as follows: the image light from the first display screen enters the waveguide prism, undergoes one or more total reflections inside the waveguide prism, and then hits the partial reflector on the rear side of the waveguide prism. Part of the light is reflected out of the waveguide prism and hits the partial reflector on the second lens. After being reflected and amplified by the concave surface of the second lens, it passes through the waveguide prism and the waveguide compensation lens and enters the human eye.

[0033] The transmission path of light for the second display screen is as follows: the image light of the second display screen passes through the first lens, reaches the second lens, is reflected by the convex surface on the front side, and reaches the concave surface of the first lens. After being reflected and amplified again, it passes through the second lens, waveguide prism, and waveguide compensation lens in sequence before entering the human eye.

[0034] Example 2

[0035] A dual-screen display optical device, such as Figure 2 As shown, a 1 / 4 glass slide 11 is provided behind each of the first lens 2 and the second lens, which can correct the light of the lens and prevent image distortion.

[0036] Example 3

[0037] This embodiment is based on the second embodiment, and the optical components and the positions of the first display screen and the second display screen are configured so that the focal lengths of the images formed by the two display screens in the human eye are the same or similar, and the images of the two display screens are formed on the same plane, such as Figure 3 、 4 shown. Figure 3 It is to set the imaging effect of the two display screens with equal image areas. Figure 4 It is an imaging effect in which the image areas of the two display screens are unequal. For example, the field of view angle of the first display screen is set to 40-60 degrees, and the field of view angle of the second display screen is set to more than 60 degrees, and the first display screen has a high resolution, and the second display screen has a low resolution. In this way, the second display screen can play large-screen pictures with lower clarity requirements (suitable for displaying images), and the first display screen can play small-screen pictures with higher clarity requirements (suitable for displaying text), which can meet the requirements of high resolution in the central small field of view and low resolution in the peripheral large field of view. With this solution, the requirements of different resolutions of images and text can be met through dual-screen display, and the superimposed display of images and text can be realized. The small screen can be placed in the middle of the large screen (such as Figure 4 ), or at the edge of a large screen.

[0038] Example 4

[0039] This embodiment is based on the second embodiment, and by setting some components to be movable, the focal length of the first display screen and the second display screen can be adjusted, and the imaging effects of different planes can be achieved (such as Figure 5 ). Specifically, the first display screen can be set to move up and down, or the second lens group can be set to move forward and backward. When the first display screen moves up or down, the optical path of the light on the first display screen becomes longer or shorter, and the imaging focal length becomes larger or smaller, which is different from the imaging focal length of the second display screen, achieving a front-and-back imaging effect. When the second lens group moves forward or backward, it affects the optical paths of the image light on the first display screen and the second display screen at the same time, one becomes longer and the other becomes shorter, thereby adjusting their respective focal lengths. When the eye's attention is focused on the content displayed on the front screen, the content displayed on the front screen is clearly imaged in the eye, and the content displayed on the rear screen is blurred; when the eye's attention is focused on the content displayed on the rear screen, the content displayed on the front screen is blurred, and the content displayed on the rear screen is displayed clearly. This solution is suitable for related game applications, or image display effects.

[0040] Example 5

[0041] On the basis of Example 2, the second display screen is set as a rotating scanning screen (eg Figure 6 、 7 ), during the rotation of the rotating scanning screen, it can not only display images for optical components to form images, but also transmit external ambient light to see external scenes. This dual-screen display device is suitable for installation on AR glasses to achieve a mixed reality effect.

Claims

1. A dual-screen display optical device, comprising an optical assembly, characterized in that: The optical assembly further comprises a first display screen disposed above the optical assembly and a second display screen disposed in front of the optical assembly, wherein the optical assembly comprises a first lens group, a second lens group, and a waveguide lens group arranged in sequence front to back, wherein the image light of the first display screen enters the human eye after being reflected and / or refracted by the waveguide lens group and the second lens group; the image light of the second display screen enters the human eye after being reflected and / or refracted by the first lens group, the second lens group, and the waveguide lens group; the first lens group comprises a first lens and a first partial reflector, wherein the first lens is a curved lens with uniform thickness, and comprises a convex surface and a concave surface, wherein the convex surface is close to the second display screen and the concave surface is close to the second display screen. The optical component is configured to be close to the second lens group, and the first partial reflector is arranged on the concave surface of the first lens; the second lens group includes a second lens and a second partial reflector, the second lens is a curved lens with uniform thickness, the second lens includes a convex surface and a concave surface, the convex surface is close to the first lens group, and the concave surface is close to the waveguide lens group, and the second partial reflector is arranged on the convex surface of the second lens; the second lens group can move back and forth to adjust the position of the images of the first display screen and the second display screen in the human eye after passing through the optical component, so as to achieve a display effect in which the images of the first display screen and the second display screen are in the same focal plane at the human eye or have a greater depth of field contrast.

2. The dual-screen display optical device according to claim 1, wherein: After being reflected and / or refracted by the optical component, the images of the first display screen and the second display screen are superimposed at the human eye, the displayed contents match each other, and the display images are located in the same plane or different planes.

3. The dual-screen display optical device according to claim 1, wherein: The waveguide lens assembly includes a waveguide prism, a waveguide compensator, and a third partial reflector. The waveguide prism is close to the first display screen, and the waveguide compensator is located below the waveguide prism. The two are bonded along an inclined surface to form an optical lens of uniform thickness. The third partial reflector is arranged between the waveguide prism and the waveguide compensator.

4. The dual-screen display optical device according to claim 3, wherein: The first, second and third partial reflectors partially transmit and partially reflect light, and the first, second and third partial reflectors are semi-transmissive and semi-reflective films or reflective polarizing films.

5. The dual-screen display optical device according to any one of claims 1 or 2, characterized in that: The image display area of ​​the first display screen is smaller than the image display area of ​​the second display screen, and the resolution of the first display screen is greater than that of the second display screen.

6. The dual-screen display optical device according to claim 1 or 2, characterized in that: The first display screen is movable. When the first display screen is moved, the imaging focal length of the first display screen at the human eye through the optical component changes.

7. The dual-screen display optical device according to claim 4, wherein: The first lens group further includes a first 1 / 4 glass plate arranged behind the first lens, and / or the second lens group further includes a second 1 / 4 glass plate arranged behind the second lens.

8. The dual-screen display optical device according to claim 1 or 2, characterized in that: The second display screen is a rotating scanning screen, and the external ambient light can pass through the display screen and the optical components into the human eye, thereby realizing the simultaneous display of the second display screen image and the external environment image.

9. A head-mounted display device, characterized in that: A dual-screen display optical device according to any one of claims 1 to 8.

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