A bifocal optical module and a magnifying teleidoscope

Abstract

The application discloses a bifocal optical module and an amplification and long-distance projection device, which comprises a lens, a plane beam splitter, a first concave mirror and a second concave mirror. The lens is used for receiving light provided by a display. After being refracted by the lens, the light is shot to the plane beam splitter. Part of the light is reflected by the plane beam splitter to the first concave mirror, is transmitted through the plane beam splitter after being reflected by the first concave mirror, is shot to a human eye, and is imaged at a first focal plane position. Part of the light is transmitted through the plane beam splitter, is shot to the second concave mirror, is reflected by the second concave mirror, is reflected by the plane beam splitter, is shot to the human eye, and is imaged at a second focal plane position. At least one of the light transmitted through the plane beam splitter to the human eye and the light shot to the human eye through the plane beam splitter is convergent light. Through the device, a viewer can watch an amplified and long-distance projected picture of the display and receive positive defocus stimulation at the same time, and myopia prevention and control is realized.

Description

Technical Field

[0001] This invention relates to a dual-focal-plane optical module and a magnified projection device. Background Technology

[0002] With the rapid development of electronic technology and education, electronic devices such as mobile phones, tablets, and computers are widely used. Especially for teenagers with highly prevalent online education, the frequency of screen use has increased dramatically in recent years. However, the intensity of light shining directly into the eyes from electronic screens is greater than that from printed books, and is accompanied by blue light stimulation and flickering, making it very easy for teenagers to spend long periods of time at close range, increasing the probability of developing myopia and worsening existing myopia. Therefore, how to provide an electronic device that can control vision problems has become an urgent issue to be addressed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a dual-focal-plane optical module and a magnified projection device.

[0004] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0005] A dual-focal-plane optical module includes: a lens, a planar beam splitter, a first concave mirror, and a second concave mirror; wherein,

[0006] The lens is used to receive light provided by the display;

[0007] The light rays are refracted by the lens and then directed towards the planar beam splitter. Part of the light is reflected by the planar beam splitter to the first concave mirror, and after reflection by the first concave mirror, it passes through the planar beam splitter and is directed towards the human eye, forming an image at the first focal plane. Another part of the light passes through the planar beam splitter and is directed towards the second concave mirror, and after reflection by the second concave mirror, it is reflected by the planar beam splitter and is directed towards the human eye, forming an image at the second focal plane.

[0008] At least one of the light rays that pass through the planar beam splitter and reach the human eye is converging.

[0009] Preferably, the planar beam splitter is equipped with a polarizing beam splitter film.

[0010] Preferably, a quarter-wave plate is provided between the planar beam splitter and the first concave mirror, and a quarter-wave plate is provided between the planar beam splitter and the second concave mirror.

[0011] Preferably, the surfaces of the first concave mirror and the second concave mirror are provided with a total reflection film.

[0012] Preferably, the radius of curvature of the first concave mirror and the second concave mirror is in the range of 400mm to 600mm.

[0013] Preferably, the distance between the second concave reflector and the planar beam splitter is adjustable.

[0014] Preferably, the distance from the first concave reflector to the planar beam splitter is adjustable.

[0015] Preferably, the lens is a single lens, a positive-negative cemented lens, or a lens group consisting of multiple lenses.

[0016] Preferably, the exit pupil distance of the dual-focal-plane optical module is between 150mm and 300mm, the exit pupil diameter is not less than φ60mm, and the field of view is not less than 35° and not more than 42°.

[0017] A magnifying and projection device includes the aforementioned dual-focal-plane optical module and a display for providing light to the planar beam splitter.

[0018] The dual-focal-plane optical module and magnification projection device provided by this invention include: a lens, a planar beam splitter, a first concave reflector, and a second concave reflector; wherein the first display optical path and the second display optical path share the display, the lens, and the planar beam splitter; and each image is formed at different focal plane positions through its respective BB optical path. By using the above-mentioned dual-focal-plane optical module to image at two different focal plane positions, viewers can receive positive defocus stimulation while normally viewing the magnified projection image on the display, thus achieving myopia prevention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall optical path of the dual-focal-plane optical module provided in the embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the optical path of the first display optical path;

[0021] Figure 3 This is a schematic diagram of the optical path of the second display optical path;

[0022] Figure 4 This is a schematic diagram of the internal structure of the magnified projection device provided in the embodiment of the present invention. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0024] This application provides a magnifying and projection device, including a dual-focal-plane optical module. The dual-focal-plane optical module includes two display optical paths sharing a common optical path. This common optical path includes a display IMA, a lens L4, and a planar beam splitter L1. Light emitted from the display IMA is refracted by the lens L4 and then directed to the planar beam splitter L1. The planar beam splitter L1 guides the light to two different concave mirrors L2 and L3, which reflect it. The light is then directed to the human eye by the planar beam splitter L1. The light from the two display optical paths forms an image in the human eye. Each display optical path has an independent focal plane, and the two focal planes are located at different positions. By adjusting the focal plane positions of the two display optical paths, one display optical path is made to match the user's vision, while the other is a positive defocus display optical path. The light entering the eye from the positive defocus display optical path is converging, enabling defocus imaging in front of the retina. This achieves a display device based on defocus stimulation, which helps in myopia control.

[0025] Specifically, such as Figure 1 As shown, the dual-focal-plane optical module provided in this embodiment of the invention includes a planar beam splitter L1, a first concave mirror L2, a second concave mirror L3, a lens L4, and a display IMA; the planar beam splitter L1, the first concave mirror L2, the lens L4, and the display IMA are arranged in sequence to form a first display optical path; the planar beam splitter L1, the second concave mirror L3, the lens L4, and the display IMA are arranged in sequence to form a second display optical path; wherein, the display IMA, the lens L4, and the planar beam splitter L1 are shared by the two display optical paths.

[0026] The present invention aims to provide a magnified projection device with a large volume of dual-focal-plane optical module and large exit pupil distance, exit pupil diameter and virtual image distance.

[0027] In this dual-focal-plane optical module, a single display optical path constitutes the Birdbath optical path (abbreviated as BB optical path). Preferably, the single display optical path constitutes a coaxial optical system.

[0028] The display IMA can be made of LCD, OLED, or other display devices. Preferably, due to the large field of view, exit pupil distance, and exit pupil diameter of the system, using a display device that is too small would increase design complexity. Therefore, an LCD or OLED display device of 5.5 inches or larger is selected as the image source. The brightness of the display device IMA is in the range of 400 cd / m². 2 ~4500cd / m 2 At this time, the light entering the human eye is of moderate brightness, resulting in a better viewing experience.

[0029] Lens L4 can be a single lens, a cemented lens, or a lens group consisting of multiple lenses. For example, in Figure 1In the illustrated embodiment, lens L4 is a positive lens. In other embodiments not shown, lens L4 can be a cemented lens to correct aberrations. Lens L4 can be a spherical glass lens or an aspherical glass lens.

[0030] A planar beam splitter L1 is placed at a predetermined angle to the display IMA, the angle ranging from 30° to 60°, preferably 45° for optimal display effect. The planar beam splitter L1 is used to split the light rays emitted from the display IMA, causing the light reflected by the planar beam splitter L1 to be directed towards the first concave reflector L2, while simultaneously directing the light rays transmitted through the planar beam splitter L1 towards the second concave reflector. The planar beam splitter L1 is equipped with a film having a predetermined transmittance-to-reflection ratio; preferably, a beam splitter film with a transmittance-to-reflection ratio of 5:5 is used.

[0031] A first concave mirror L2 is positioned along the propagation path of light reflected by the planar beam splitter L1, reflecting a portion of the light back to the planar beam splitter L1. The first concave mirror L2 is concave towards the planar beam splitter L1. The radius of curvature of the first concave mirror L2 ranges from 400mm to 600mm, and its surface shape is spherical, aspherical, or freeform. A total internal reflection film or a beam splitter film with a predetermined transmission-to-reflection ratio is attached to the first concave mirror L2. When the first concave mirror L2 is equipped with a total internal reflection film, the dual-focal-plane optical module can achieve a display similar to virtual reality; when the first concave mirror L2 is equipped with a beam splitter film with a predetermined transmission-to-reflection ratio, the dual-focal-plane optical module can achieve an augmented reality-type display with optical perspective, allowing ambient light to pass through the first concave mirror L2 and the planar beam splitter L1 into the human eye.

[0032] The second concave mirror L3 is positioned in the propagation path of light transmitted through the plane beam splitter L1, reflecting a portion of the light back to the plane beam splitter L1. The second concave mirror L3 is concave towards the plane beam splitter L1. The radius of curvature of the second concave mirror L3 ranges from 400mm to 600mm, and its surface shape is spherical, aspherical, or freeform. A total reflection coating is attached to the second concave mirror L3.

[0033] The first concave mirror L2 and the second concave mirror L3 can use the same parameters or different parameters. In order to make the two display optical paths image at different focal plane positions, when the first concave mirror L2 and the second concave mirror L3 use the same parameters, the distances of the first concave mirror L2 and the second concave mirror L3 to the display IMA are different.

[0034] The surface of the planar beam splitter L1 facing the display IMA is marked L1-S02, and the surface of the planar beam splitter L1 facing away from the display IMA is marked L1-S01. Light emitted from the display IMA, after being refracted by lens L4, is directed towards surface L1-S02 of the planar beam splitter L1. Figure 2 As shown, some light rays are reflected by the plane beam splitter L1 and then strike the first concave mirror L2. After being reflected by the first concave mirror L2, they strike the plane beam splitter L1 again. A portion of these light rays pass through the plane beam splitter L1 and reach the human eye. Figure 3 As shown, another portion of the light passes through the plane beam splitter L1 and is directed to the second concave mirror L3. After being reflected by the second concave mirror L2, it is directed to the surface L1-S01 of the plane beam splitter L1. Among these, some of the light is reflected by the plane beam splitter L1 and directed to the human eye.

[0035] Using the aforementioned dual-focal-plane optical module, one of the two display optical paths images the user normally, matching the user's vision, while the other path achieves defocus display. For example, for people with normal vision, one optical path projects parallel light towards the eye, and the other optical path projects converging light towards the eye. In the illustrated embodiment, as... Figure 2 The first display optical path shown is an infinity projection optical path, used to magnify and project the displayed image, allowing users to view the image normally from infinity; such as Figure 3 The second display optical path shown is the emmetropia imaging optical path, which is used for vision correction in teenagers who have already developed myopia symptoms; thus, on the one hand, it provides users with a comfortable eye experience and reduces fatigue from prolonged use, and on the other hand, it controls myopia and reduces the probability of developing the disease.

[0036] Preferably, in other embodiments, the two display optical paths use polarized optical paths, a polarizing beam splitter film is attached to the surface of the planar beam splitter L1, a quarter-wave plate is provided between the planar beam splitter L1 and the first concave reflector L2, and a quarter-wave plate is provided between the planar beam splitter L1 and the second concave reflector L3. Thus, the light rays emitted from the display IMA towards the planar beam splitter L1 are split into two parts: p-type polarized light and s-type polarized light. The s-type polarized light is reflected by the planar beam splitter L1 to the first concave mirror L2. During this process of the s-type polarized light traveling from the planar beam splitter L1 to the first concave mirror L2 and being reflected back to the planar beam splitter L1, it passes through a quarter-wave plate twice, changing its polarization direction to p-type polarized light, which then passes through the planar beam splitter L1 and reaches the human eye. The p-type polarized light, passing through the planar beam splitter L1, travels towards the second concave mirror L3. During this process of the p-type polarized light traveling from the planar beam splitter L1 to the second concave mirror L3 and being reflected back to the planar beam splitter L1, it passes through a quarter-wave plate twice, changing its polarization direction to s-type polarized light, which is then reflected by the planar beam splitter L1 and reaches the human eye. By using the principle of polarized beam splitting, the light energy utilization rate of the display is improved.

[0037] The aforementioned dual-focal-plane optical module can achieve a large exit pupil distance, ranging from 150mm to 300mm, with an exit pupil diameter of not less than φ60mm and a field of view of not less than 35° and not more than 42°.

[0038] The following is a detailed parameter description of an embodiment with an exit pupil diameter of 60×90mm, an exit pupil distance of 200mm, and a field of view of 36°. The first display optical path, from the human eye observation side to the display side, consists of, in sequence, an aperture stop (STP), a planar beam splitter (L1), a first concave reflector (L2), a lens (L4), and a display device (IMA). The second display optical path, from the human eye observation side to the display device side, consists of, in sequence, an aperture stop (STP), a planar beam splitter (L1), a second concave reflector (L3), a lens (L4), and a display device (IMA). The aperture stop (STP) surface number is 1, and so on. The surface number of lens L4 facing the planar beam splitter (L1) is 7, the surface number facing the display device (IMA) is 8, the screen protection glass surface number is 9, and the display device (IMA) surface number is 10. The optical design data for the first display optical path (infinity projection optical path) of this embodiment is shown in Table 1; the optical design data for the second display optical path (positive diopter correction optical path) of this embodiment is shown in Table 2.

[0039] Table 1 First Display Optical Path Parameter Table

[0040]

[0041] Table 2. Parameters of the Second Display Optical Path

[0042]

[0043] In this embodiment, the combined focal length of the planar beam splitter L1, the first concave mirror L2, and the single convex lens L4 is f. 124 The combined focal length of the plane beam splitter L1, the second concave mirror L3, and the single convex lens L4 is f. 134 The focal length of the single convex lens L4 is f4; the radii of curvature of the first concave mirror L2 and the second concave mirror L3 are R2 and R3, respectively.

[0044] The parameters satisfy the following relationship:

[0045] (1) 1.4 <f4 / f 124 <2.6

[0046] (2) 0.98 <f4 / f 134 <1.97

[0047] (3) 400mm <R2<600mm

[0048] (4) 400mm <R3<600mm

[0049] Furthermore, the materials of the planar beam splitter L1 and the single convex lens L4 meet the following requirements:

[0050] Nd1>1.5, Nd4>1.5, Vd1>40, Vd4>40;

[0051] Nd1 and Nd4 represent the refractive indices of the plane beam splitter L1 and the single convex lens L4 at the d-line, respectively. Vd1 and Vd4 represent the Abbe numbers of the plane beam splitter L1 and the single convex lens L4 at the d-line, respectively. Both are greater than 40.

[0052] This application also provides the internal structure of the magnified projection device, such as... Figure 4 As shown, the device includes a mounting bracket 1, which is fixed inside the housing. Taking the side where the human eye is located as the front, the display 2 is located on top of the mounting bracket 1, the planar beam splitter 4 is located inside the mounting bracket 1, and the normal angle between the display 2 and the planar beam splitter 4 is 45 degrees; the first concave reflector 3 is located on the rear side of the mounting bracket 1, and the second concave reflector 5 is located below the mounting bracket 1.

[0053] In this embodiment, the distance between the second concave reflector 5 and the planar beam splitter 4 is adjustable. The second concave reflector 5 can move up and down via a displacement platform 6. The displacement platform 6 is located at the bottom of the mounting bracket 1 and includes a fixed platform and a moving platform that are parallel to each other. The fixed platform is fixedly connected to the mounting bracket 1. The second concave reflector 5 is fixed on the moving platform. The moving platform can reciprocate relative to the fixed platform in the optical axis direction, thereby adjusting the distance between the second concave reflector 5 and the display IMA to change the position of the focal plane and the virtual image distance.

[0054] In summary, the dual-focal-plane optical module and magnification projection device provided by this invention include: a lens, a planar beam splitter, a first concave reflector, and a second concave reflector; wherein the first display optical path and the second display optical path share the display, the lens, and the planar beam splitter, and respectively image at different focal plane positions through their respective BB optical paths. The aforementioned dual-focal-plane optical module images at two different focal plane positions, with one defocus imaging optical path, allowing the viewer to receive positive defocus stimulation while normally viewing the magnified projection image on the display, thus achieving myopia prevention.

[0055] The foregoing has provided a detailed description of the dual-focal-plane optical module and magnification projection device provided by this invention. Any obvious modifications made by those skilled in the art without departing from the essential content of this invention will constitute an infringement of the patent rights of this invention and will incur corresponding legal liability.

Claims

1. A dual-focal-plane optical module, suitable for magnified projection devices used to achieve myopia control, characterized in that, include: Lens, plane beam splitter, first concave mirror, and second concave mirror; wherein, The lens is used to receive light provided by the display; The light rays are refracted by the lens and then directed towards the planar beam splitter. Part of the light is reflected by the planar beam splitter to the first concave mirror, and after reflection by the first concave mirror, it passes through the planar beam splitter and is directed towards the human eye, forming an image at the first focal plane. Another part of the light passes through the planar beam splitter and is directed towards the second concave mirror, and after reflection by the second concave mirror, it is reflected by the planar beam splitter and is directed towards the human eye, forming an image at the second focal plane. The light rays that pass through the plane beam splitter and are incident on the human eye, and the light rays that are incident on the human eye after being reflected by the plane beam splitter, one of which is parallel light and the other is converging light, forming positive defocus; The exit pupil distance of the dual-focal-plane optical module is between 150mm and 300mm, the exit pupil diameter is not less than φ60mm, and the field of view is not less than 35° and not more than 42°. The combined focal length of the planar beam splitter, the first concave mirror, and the lens is f. 124 The combined focal length of the plane beam splitter, the second concave mirror, and the lens is f. 134 The focal length of the lens is f4; the focal length of the lens f4 and the combined focal length f 124 f 134 The following relationship must be satisfied: (1) 1.4<f4 / f 124 <2.6; (2) 0.98<f4 / f 134 <1.97。 2. The dual-focal-plane optical module as described in claim 1, characterized in that: The planar beam splitter is equipped with a polarizing beam splitter film.

3. The dual-focal-plane optical module as described in claim 2, characterized in that: A quarter-wave plate is provided between the planar beam splitter and the first concave reflector; A quarter-wave plate is provided between the planar beam splitter and the second concave reflector.

4. The dual-focal-plane optical module as described in claim 1, characterized in that: The lens is a single lens, a positive-negative cemented lens, or a lens group consisting of multiple lenses.

5. The dual-focal-plane optical module as described in claim 1, characterized in that: The surfaces of the first concave reflector and the second concave reflector are provided with total reflection films.

6. The dual-focal-plane optical module as described in claim 1, characterized in that: The radius of curvature of the first concave reflector and the second concave reflector ranges from 400mm to 600mm.

7. The dual-focal-plane optical module as described in claim 1, characterized in that: The distance between the second concave reflector and the planar beam splitter is adjustable.

8. The dual-focal-plane optical module as described in claim 1, characterized in that: The distance between the first concave reflector and the planar beam splitter is adjustable.

9. A magnifying and projection device, comprising a dual-focal-plane optical module as described in any one of claims 1-8, characterized in that: It also includes a display for providing light to the planar beam splitter.

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