Imaging optical system and display device

Abstract

Provided is an imaging optical system and a display device capable of increasing the viewing angle. The imaging optical system (100) includes a flat lens (1) and a reflecting assembly (5). The flat lens (1) includes two sets of optical waveguide arrays (10). The reflecting assembly (5) has at least one pair of reflecting surfaces (5s), and the two reflecting surfaces (5s) of the pair are located on the image source side and the viewing side of the flat lens (1), respectively, and the angle between the reflecting surface (5s) and the flat lens (1) is 90 degrees or less, the angles between the two reflecting surfaces (5s) of the pair and the flat lens (1) are equal, and the intersection lines between the two reflecting surfaces (5s) of the pair and the flat lens (1) are parallel.

Description

[Technical Field]

[0001] This application relates to the field of optical equipment manufacturing, and more particularly to imaging optics and display devices that allow for increased viewing angles. [Background technology]

[0002] A flat lens utilizes two layers of periodically distributed arrayed optical waveguides that are perpendicular to each other to cause light rays to undergo total internal reflection once on each of the two layers of arrayed optical waveguides. Because of their perpendicular rectangular structure, the angle of incidence at the first total reflection is the same as the angle of emergence at the second total reflection. All light rays within the divergence angle of the light source pass through the flat lens and converge accordingly at a spatial position symmetrical to the plane of the light source, resulting in a 1:1 aerial real image. However, existing imaging structures like this have drawbacks, such as a small viewing angle on the visual side, meaning that viewers cannot see the real image if they deviate by a certain angle from the central axis of the flat lens. Because of these characteristics, flat lenses are not suitable for public exhibitions. Therefore, it is particularly important to develop a method to increase the viewing angle of flat lenses.

[0003] Among the common methods for increasing the viewing angle in the prior art, some result in distortion of the real image, some have complex structures and are too costly to be widely used in public areas, and some only have a limited range of viewing angle. How to achieve a significant increase in the viewing angle with a flat lens using a simple structure is one of the research directions in this field. Summary of the Invention [Problem to be solved by the invention]

[0004] The present application aims to solve one of the technical problems existing in the prior art by providing an imaging optical system that increases the viewing angle of a flat lens with a simple configuration.

[0005] Another object of the present application is to provide a display device including the imaging optical system. [Means for solving the problem]

[0006] According to an embodiment of the present application, an imaging optical system includes a flat lens and a reflection assembly, the flat lens includes two sets of optical waveguide arrays, each set of the optical waveguide arrays is composed of sub-waveguides arranged in a single column and a plurality of rows, each having a rectangular cross section, the two sets of optical waveguide arrays include a first optical waveguide array and a second optical waveguide array, the sub-waveguides of the first optical waveguide array extend along the X direction and form a plurality of rows along the Y direction, the sub-waveguides of the second optical waveguide array extend along the Y direction and form a plurality of rows along the X direction, the first optical waveguide array and the second optical waveguide array are arranged along the Z direction, and the X direction, the Y direction and the Z direction are perpendicular to each other, the flat lens has a central normal that passes through the center of the flat lens and is parallel to the Z direction, opposite sides of the flat lens are the image source side and the eye side, respectively, the reflection assembly has at least one pair of reflective surfaces, the two reflective surfaces of the pair are located on the image source side and the eye side, respectively, all of the reflective surfaces are planar and are installed toward the central normal, the angle formed by the reflective surface and the flat lens is 90 degrees or less, the angles formed by the two reflective surfaces of the pair and the flat lens are equal, and the intersection lines between the two reflective surfaces of the pair and the flat lens are parallel to each other.

[0007] In the imaging optical system of the present application, reflective surfaces are installed on both the image source side and the viewer side of the flat lens, and the reflective surfaces are installed in pairs, thereby enabling the reflective surfaces to increase the viewing angle, and in some cases the reflective surfaces can even increase the viewing angle to 180 degrees. In this way, when viewers view the aerial real image on the viewer side, the increased viewing angle allows more viewers to see it, making the imaging optical system applicable to public exhibition areas and surpassing the limitations of a single flat lens. Furthermore, reflecting light with the reflective surface increases the utilization rate of light around the light source, allowing the reflective surface to direct more light toward the aerial real image, thereby enhancing the brightness and clarity of the aerial real image and improving imaging quality.

[0008] In some embodiments, one side of the reflecting surface is in close contact with the flat lens.

[0009] In some embodiments, the reflecting assembly includes a plurality of pairs of the reflecting surfaces, the plurality of pairs of the reflecting surfaces being arranged along directions surrounding the central normal.

[0010] Specifically, the multiple pairs of reflecting surfaces include two pairs of reflecting surfaces located on opposite sides of the central normal, and in the two pairs of reflecting surfaces located on opposite sides of the central normal, the angles formed by each of the reflecting surfaces and the flat lens are equal, and the intersection lines between each of the reflecting surfaces and the flat lens are parallel to each other.

[0011] In some embodiments, the two reflecting surfaces of the same pair are arranged symmetrically with respect to the flat lens.

[0012] In some embodiments, the reflecting assembly includes at least two reflecting mirrors, the reflecting mirrors being plane mirrors, and the surface of each of the reflecting mirrors facing the center normal constitutes the reflecting surface.

[0013] According to an embodiment of the display device of the present application, the display device comprises the imaging optical system described in the above embodiment of the present application and a display, the display being positioned on the image source side and the display screen of the display being arranged facing the flat lens.

[0014] According to the display device of the present application, a pair of reflective surfaces are installed on both sides of a flat lens, thereby enabling the reflective surfaces to increase the viewing angle, and in some cases the reflective surfaces can increase the viewing angle up to 180 degrees. In this way, when an audience member views the aerial real image from the viewing side, the increased viewing angle allows more audience members to see it, making the display device applicable to public areas for exhibitions and breaking through the limitations of display device use. Furthermore, by reflecting light rays with the reflective surfaces, the utilization rate of light rays around the light source can be increased, and the reflective surfaces can irradiate more light rays toward the aerial real image, which is advantageous for improving imaging quality.

[0015] In some specific embodiments, the display screen is a straight plate screen, the angle between the display screen and the flat lens is an acute angle, the four sides of the display screen are a near side, a far side and two inclined sides, the near side and the far side are opposite sides of the display screen, the near side is located on the side of the display screen closer to the flat lens, and on the image source side, the reflecting surfaces are respectively provided on both sides of the display screen corresponding to the two inclined sides, and / or the reflecting surface is provided on one side of the display screen corresponding to the far side.

[0016] In some alternative embodiments, the reflective surface corresponding to the inclined edge is a first reflective surface for increasing the viewing angle, and a projection formed along a direction parallel to the flat lens of the display screen is located entirely within the first reflective surface for increasing the viewing angle.

[0017] Specifically, the first reflective surface for increasing the viewing angle is triangular or trapezoidal, and the projection formed along a direction parallel to the flat lens of the display screen is flush with one side of the first reflective surface for increasing the viewing angle.

[0018] Furthermore, the reflective surface corresponding to the far side is a second reflective surface for increasing the viewing angle, and the second reflective surface for increasing the viewing angle is rectangular.

[0019] Optionally, the first viewing angle enhancing reflecting surface is triangular, and a projection of the display screen formed along a direction parallel to the flat lens is flush with one side of the first viewing angle enhancing reflecting surface, and a projection of the second viewing angle enhancing reflecting surface formed along a direction parallel to the flat lens is flush with another side of the first viewing angle enhancing reflecting surface.

[0020] Additional aspects and advantages of the present application will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the present application. [Brief explanation of the drawings]

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easier to understand from the following description of the embodiments taken in conjunction with the drawings. [Figure 1] 1 is a structural schematic diagram of an imaging optical system according to an embodiment of the present application; [Figure 2] 1 is a schematic structural diagram of a flat lens according to an embodiment of the present application; [Figure 3] 3 is a partial enlarged view of part K in FIG. 2 as viewed from the side. [Figure 4] FIG. 2 is an exploded view of a flat lens according to an embodiment of the present application. [Figure 5] 1 is a structural schematic diagram of two layers of orthogonal optical waveguide arrays arranged along the Z direction according to an embodiment of the present application. [Figure 6] FIG. 1 is a schematic diagram of an imaging of two layers of orthogonal optical waveguide arrays according to an embodiment of the present application. [Figure 7] 1 is a schematic diagram illustrating imaging in the X direction when a light source image passes through a single-layer optical waveguide array according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a schematic diagram of imaging in a three-dimensional direction when the light source image shown in FIG. 7 passes through a single-layer optical waveguide array. [Figure 9] 1 is a diagram illustrating the principle of imaging light paths when a light source image passes through two layers of orthogonal optical waveguide arrays according to an embodiment of the present disclosure. [Figure 10] 1 is a structural schematic diagram of a first display device according to a first embodiment of the present invention. [Figure 11] 3 is a schematic diagram illustrating the principle of horizontal viewing field expansion of the first display device according to the first embodiment of the present invention. FIG. [Figure 12] FIG. 10 is a structural schematic diagram of a second display device according to a second embodiment of the present invention. [Figure 13] FIG. 10 is a schematic diagram illustrating the principle of horizontal viewing field expansion of a second display device according to a second embodiment of the present invention. [Figure 14] FIG. 10 is a structural schematic diagram of a third display device according to a third embodiment of the present invention. [Figure 15] FIG. 10 is a schematic diagram illustrating the principle of vertical viewing field expansion of a third display device according to a third embodiment of the present invention. [Figure 16] FIG. 10 is a structural schematic diagram of a fourth display device according to a fourth embodiment of the present invention. [Figure 17] FIG. 10 is a schematic diagram illustrating the principle of vertical viewing field expansion of a fourth display device according to a fourth embodiment of the present invention. [Figure 18] FIG. 10 is a schematic diagram illustrating the principle of vertical viewing angle expansion when γ=90° in the fourth display device according to the fourth embodiment of the present invention. [Figure 19] FIG. 10 is a schematic diagram illustrating the principle of vertical viewing angle expansion when γ>90° in the fourth display device according to the fourth embodiment of the present invention. [Figure 20] FIG. 10 is a structural schematic diagram of a fifth display device according to a fifth embodiment of the present invention. [Figure 21] FIG. 10 is a side view of a fifth display device according to a fifth embodiment of the present invention. [Figure 22] FIG. 2 is a structural schematic diagram of a display device according to another embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, the embodiments of the present application will be described in detail. The examples of the embodiments are shown in the drawings, and the same or similar reference numerals throughout the drawings indicate the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are illustrative and are intended to explain the present application, and should not be understood as limiting the present application.

[0023] An imaging optical system 100 according to an embodiment of the present invention will be described below with reference to the drawings.

[0024] As shown in FIG. 1, an imaging optical system 100 according to an embodiment of the present application includes a planar lens 1 and a reflecting assembly 5 .

[0025] Opposite sides of the flat lens 1 are the image source side and the visual side, respectively. That is, the light source of the image P1 is located on the image source side, and the image P1 passes through the flat lens 1 to form an aerial real image P2 on the visual side. The aerial real image P2 is a real image floating in the air. Here, as shown in FIGS. 2 to 4, the flat lens 1 has an optical structure in which two layers of periodically distributed optical waveguide arrays 10 are orthogonal to each other, causing light rays to be totally reflected once by each of the two optical waveguide arrays 10. Because the two optical waveguide arrays 10 have a rectangular structure that is orthogonal to each other, the angle of incidence at the first total reflection and the angle of emergence at the second total reflection are the same. After passing through the flat lens 1, light rays within the divergence angle of the light source light rays converge toward the visual side accordingly, resulting in an aerial real image P2 whose size is 1:1 with respect to the size of the image P1.

[0026] The divergence angle of the light rays of the aerial real image P2 can be regarded as the viewing angle for the aerial real image P2 on the viewing side. Combined with the characteristic that the image P1 and the aerial real image P2 are symmetrical with respect to the flat lens 1, the angle of the light rays from the light source of the image P1 to the flat lens 1 is approximately equal to the divergence angle of the light rays of the aerial real image P2. Therefore, the larger the area of ​​the flat lens 1, the larger the viewing angle for the aerial real image P2.

[0027] In practical applications, the area of ​​the flat lens 1 cannot be made too large, so imaging with a conventional flat lens 1 is characterized by a small field of view. For example, there is a flat lens 1 with a horizontal field of view of approximately ±30 degrees, and if the position of the eyes deviates from this range of the field of view, the resulting real image becomes invisible. Particularly in public areas, only a narrow range of spectators directly facing the flat lens 1 can see a clear real image, and if the position is slightly off, it is difficult to see a clear real image.

[0028] To solve this problem, the present application provides a reflecting assembly 5 in the imaging optical system 100, and uses the reflecting surface 5s of the reflecting assembly 5 in combination with the flat lens 1 for imaging.

[0029] See Fig. 1. The reflection assembly 5 has at least one pair of reflection surfaces 5s, and the two reflection surfaces 5s of the same pair are located on the image source side and the viewer side, respectively. In the drawings of this application, the two reflection surfaces 5s of the same pair located on the image source side and the viewer side are denoted as 5P.

[0030] The reflecting surface 5s is flat and is disposed facing the central normal L1 of the flat lens 1, with the angle α between the reflecting surface 5s and the flat lens 1 being 90 degrees or less. The flat lens 1 has a central normal L1, which is a reference line introduced in this application to explain the configuration of the imaging optical system 100. The central normal L1 passes through the center of the flat lens 1 and is parallel to the thickness direction of the flat lens 1. The center of the flat lens 1 is the centroid of the flat lens 1.

[0031] A reflecting surface 5s is provided on the image source side, and light rays from the light source of the image P1 to the reflecting surface 5s can be reflected onto the flat lens 1. By providing a reflecting surface 5s on the corresponding viewing side, light rays emitted from the flat lens 1 can be reflected onto the aerial real image P2 via the reflecting surface 5s. In this way, by providing the same pair of reflecting surfaces 5s, light rays from the light source of the image P1 that cannot be emitted onto the flat lens 1 can be irradiated onto the flat lens 1 by the reflecting surface 5s. This increases the angle of light rays from the light source of the image P1 to the flat lens 1, and therefore the divergence angle of the light rays of the aerial real image P2. Therefore, by providing the reflecting assembly 5, the field of view of the imaging optical system 100 can be increased compared to a means without providing the reflecting assembly 5.

[0032] Here, the reflecting surface 5s is flat, which can prevent deformation of the aerial real image P2. The angle α between the pair of reflecting surfaces 5s and the flat lens 1 is equal, and the intersection lines between the pair of reflecting surfaces 5s and the flat lens 1 are parallel to each other. In this way, the reflection paths of the light rays from the pair of reflecting surfaces 5s can be made symmetrical with respect to the flat lens 1, which further prevents deformation of the aerial real image P2. When the reflecting surface 5s is in contact with the flat lens 1, the intersection line between the reflecting surface 5s and the flat lens 1 is the contact line between the reflecting surface 5s and the flat lens 1. When the reflecting surface 5s is not in contact with the flat lens 1, the intersection line between the reflecting surface 5s and the flat lens 1 is the intersection line between the reflecting surface 5s and the flat lens 1 in the extension direction.

[0033] The angle α between the reflecting surface 5s and the flat lens 1 is 90 degrees or less, which is advantageous for controlling the size of the imaging optical system 100 within a reasonable range. If the angle α between the reflecting surface 5s and the flat lens 1 is greater than 90 degrees, the reflecting surface 5s will be open relative to the means where the reflecting surface 5s is perpendicular to the flat lens 1. The open reflecting surface 5s will reflect a portion of the light beam away from the flat lens 1, and this portion of the light beam will become ineffective. Therefore, in order to increase the effective utilization rate of the light beam, the means of the present application sets the angle α between the reflecting surface 5s and the flat lens 1 to 90 degrees or less.

[0034] As can be seen from this, by controlling the magnitude of the angle α formed between the reflecting surface 5s and the flat lens 1, the objective of adjusting the imaging field angle can be achieved.

[0035] In the imaging optical system 100 according to the embodiment of the present application, reflective surfaces 5s are respectively installed on the image source side and the viewer side of the flat lens 1, and the reflective surfaces 5s are installed in pairs, thereby enabling the reflective surfaces 5s to increase the field of view angle, and in some cases, the reflective surfaces 5s can increase the field of view angle up to 180 degrees. In this way, when viewers view the aerial real image P2 on the viewer side, the increased field of view allows more viewers to see it, making the imaging optical system 100 applicable to public areas for exhibitions and breaking through the limitations of using a single flat lens 1. In addition, using the reflective surfaces 5s to reflect light rays can increase the utilization rate of light rays from the light source edge, allowing more light rays to be irradiated onto the aerial real image P2 by the reflective surfaces 5s, thereby increasing the brightness and clarity of the aerial real image P2 and favoring improved imaging quality.

[0036] In order to better understand the technical means of the present application, the basic configuration and imaging principle of the flat lens 1 will be described below with reference to FIGS.

[0037] 2 to 4, the flat lens 1 includes two sets of optical waveguide arrays 10. Each set of optical waveguide arrays 10 is made up of sub-waveguides 101 arranged in a single column and multiple rows, and each sub-waveguide 101 has a rectangular cross section. Here, the transverse cross section of the sub-waveguide 101 is the cross section of the sub-waveguide 101 in a direction perpendicular to its longitudinal direction.

[0038] 3 to 5. The two sets of optical waveguide arrays 10 include a first optical waveguide array 11 and a second optical waveguide array 12. The sub-waveguides 101 of the first optical waveguide array 11 extend along the X direction and form multiple rows along the Y direction, and the sub-waveguides 101 of the second optical waveguide array 12 extend along the Y direction and form multiple rows along the X direction. The first optical waveguide array 11 and the second optical waveguide array 12 are arranged along the Z direction, and the X, Y, and Z directions are perpendicular to each other. Here, the extension direction of the sub-waveguides 101 is the longitudinal direction of the sub-waveguide 101, the longitudinal direction of a single sub-waveguide 101 of the first optical waveguide array 11 is the X direction, and the multiple sub-waveguides 101 of the first optical waveguide array 11 are stacked and arranged in close contact along the Y direction. The width direction of a single sub-waveguide 101 is the Y direction, the longitudinal direction of a single sub-waveguide 101 of the second optical waveguide array 12 is the Y direction, and the multiple sub-waveguides 101 of the second optical waveguide array 12 are stacked and closely arranged along the X direction. The width direction of a single sub-waveguide 101 is the X direction. Each of the two optical waveguide arrays 10 is flat, and the arrangement direction from the first optical waveguide array 11 to the second optical waveguide array 12 is the Z direction, which also corresponds to the thickness direction of the flat lens 1. Note that, in the first optical waveguide array 11 and the second optical waveguide array 12, the first optical waveguide array 11 may be closer to the image source side, or the second optical waveguide array 12 may be closer to the image source side, but this is not limited here. Because the longitudinal directions of the sub-waveguides 101 of the two layers are perpendicular to each other, the two optical waveguide arrays 10 are said to be in an orthogonal relationship.

[0039] Optionally, reflective films for total reflection of light are provided on two side surfaces in the width direction of each sub-waveguide 101. For example, reflective films are provided on two side surfaces in the Y direction of each sub-waveguide 101 of the first optical waveguide array 11, and since the first optical waveguide array 11 includes a plurality of sub-waveguides 101, a plurality of reflective films are arranged along the Y direction in the first optical waveguide array 11. Reflective films are provided on two side surfaces in the X direction of each sub-waveguide 101 of the second optical waveguide array 12, and since the second optical waveguide array 12 includes a plurality of sub-waveguides 101, a plurality of reflective films are arranged along the X direction in the second optical waveguide array 12.

[0040] 2 and 4, the flat lens 1 may include a protective cover plate 30. The protective cover plate 30 is for supporting and protecting the optical waveguide array 10. The protective cover plate 30 may be installed on only one side of the flat lens 1, or may be installed on both sides of the flat lens 1. Specifically, the protective cover plate 30 is a transparent cover plate, and optionally, the protective cover plate 30 is a glass plate.

[0041] 2 to 4 are structural schematic diagrams of a flat lens 1 according to one embodiment. The flat lens 1 includes a pair of protective cover plates 30, which are a first cover plate 31 and a second cover plate 32. The flat lens 1 further includes two sets of optical waveguide arrays 10 located between the two protective cover plates 30, which are a first optical waveguide array 11 and a second optical waveguide array 12. The X direction is the extension direction of the sub-waveguides 101 in the first optical waveguide array 11, the Y direction is the extension direction of the sub-waveguides 101 in the second optical waveguide array 12, and the Z direction is the thickness direction of the flat lens 1. Of course, in some cases, the protective cover plates 30 may not be used, and other means may be used to protect the optical waveguide arrays 10.

[0042] Optionally, as shown in Figure 5, the outer shape of the molded optical waveguide array 10 is rectangular, and the angle between the extension direction of each sub-waveguide 101 and at least two sides of the outer shape of the optical waveguide array 10 is θ. Furthermore, optionally, θ satisfies 30°≦θ≦60°, and preferably θ=45°, at which angle the aerial real image P2 is relatively clear and the afterimage is not clear.

[0043] Here, the core imaging elements of the flat lens 1 are a first optical waveguide array 11 and a second optical waveguide array 12, and the first optical waveguide array 11 and the second optical waveguide array 12 include sub-waveguides 101 arranged in a single column and multiple rows that are orthogonal to each other, and the entire flat lens 1 is flat. As shown in Figure 6, the flat lens 1 can achieve point-to-point, aberration-free imaging of an image P1.

[0044] The specific imaging principle is as follows. Here, two optical waveguide arrays 10 are divided. Take the first optical waveguide array 11 as an example, as shown in FIGS. 7 and 8. In the single-layer optical waveguide array 10, a single point light beam from the image source side passes through one of the optical waveguide arrays 10, is split and mirror-modulated by each row of sub-waveguides 101, and is then focused again into a straight line P1' parallel to the X direction, forming a point-to-line one-dimensional imaging effect. As shown in FIG. 7, the single point light beam from the image source side passes through one of the sub-waveguides 101 at an incident angle δ. After being reflected by the sub-waveguide 101, the incident angle δ is equal to the exit angle δ'.

[0045] As shown in Figure 9, in order to intersect two directions (X direction and Y direction) at one point, two sets of optical waveguide arrays 10 must be combined and used. This allows the arrangement directions of the sub-waveguides 101 in the two layers to be orthogonal to each other, enabling point-to-point modulation of the target light source image P1. Therefore, when light rays from any direction pass through the optical waveguide arrays 10 in both orthogonal layers, they can all converge again to an aerial real image P2 at a symmetrical position on the optical waveguide array 10. The imaging distance m2 of the aerial real image P2 is the same as the distance m1 to the original image, resulting in equidistant imaging. Furthermore, since the aerial real image P2 is located in the air, a real image can be directly projected into the air without the need for a carrier such as a screen.

[0046] Therefore, this flat lens 1 can directly image a two-dimensional or three-dimensional light source in the air, realizing a true holographic image. It achieves a wide field of view, a large aperture, high resolution, no distortion, and no dispersion, while also achieving naked-eye three-dimensional stereoscopic display characteristics.

[0047] In the drawings of the present application, all the flat lenses 1 are rectangular, but in other aspects of the present application, the shape of the flat lenses 1 may be adjusted as needed, for example, circular, trapezoidal, etc., but is not limited thereto.

[0048] In some embodiments, as shown in FIG. 1, the two reflective surfaces 5s of a pair are symmetrical with respect to the flat lens 1, so that the two reflective surfaces 5s of a pair have the same shape and the same area, thereby making full use of the area of ​​the reflective surfaces 5s and reducing light loss.

[0049] Specifically, each of the pair of reflecting surfaces 5s forms an intersection with the flat lens 1, and not only are the two intersections parallel, but the planes formed by the two intersections are also perpendicular to the flat lens 1. This makes it possible to avoid misalignment at the seams of the images.

[0050] In some embodiments, one side of the reflecting surface 5s is in close contact with the flat lens 1. When a gap exists between the reflecting surface 5s and the flat lens 1, a portion of the aerial real image P2 corresponding to the line connecting the human eye and the gap is missing when observed within an expanded viewing angle range. In other words, the aerial real image P2 cannot be seen within that viewing angle range. In contrast, by bringing one side of the reflecting surface 5s into close contact with the flat lens 1 and filling the gap, the viewing angle range can be effectively expanded.

[0051] Specifically, one side of each of the reflecting surfaces 5s is in close contact with the flat lens 1. In this way, by filling the gaps in all of the reflecting surfaces 5s, the viewing angle range can be further effectively widened.

[0052] In the present invention, the reflecting assembly 5 may have one, two, or three pairs of reflecting surfaces 5s. Depending on the needs of the flat lens 1 and the display 200, more pairs may be set, and this is not limited here.

[0053] When the reflection assembly 5 has multiple pairs of reflection surfaces 5s, the multiple pairs of reflection surfaces 5s are arranged along a direction surrounding the central normal L1, that is, the multiple reflection surfaces 5s surround the central normal L1 on the image source side, and the multiple reflection surfaces 5s also surround the central normal L1 on the viewing side. When arranged in this manner, the area directly facing the center of the flat lens 1 may be left empty to place the light source image P1; for example, the display screen 210 of the display 200 may be directly facing the center of the flat lens 1.

[0054] In some embodiments, as shown in Figures 10 to 13, two pairs of reflecting surfaces 5s are located on opposite sides of the central normal L1. In the two pairs of reflecting surfaces 5s located on opposite sides of the central normal L1, the angle α formed between each reflecting surface 5s and the flat lens 1 is equal, and the intersection lines between each reflecting surface 5s and the flat lens 1 are parallel to each other. In this manner, the two pairs of reflecting surfaces 5s contribute to expanding the field of view of the imaging optical system 100 in the direction in which they are located, and the two pairs of reflecting surfaces 5s may be complementary. Light rays are continuously reflected between the two pairs of reflecting surfaces 5s, and the field of view of the imaging optical system 100 in this direction can be expanded to approximately 180 degrees.

[0055] According to such an imaging optical system 100, when two pairs of reflecting surfaces 5s are arranged on both horizontal sides of the flat lens 1, the horizontal viewing angle of the imaging optical system 100 can be expanded, and when used in a public area, more spectators can be accommodated and viewed simultaneously.

[0056] 14 to 19, the imaging optical system 100 includes a pair of reflective surfaces 5s, which are located on one side of the flat lens 1. In this way, the viewing angle of an audience on the other side of the flat lens 1 can be expanded by reflection from the reflective surfaces 5s.

[0057] In some embodiments, as shown in FIG. 20, the imaging optical system 100 includes three pairs of reflecting surfaces 5s, and the three pairs of reflecting surfaces 5s are located on three sides of the flat lens 1.

[0058] Thus, the imaging optical system 100 includes four pairs of reflecting surfaces 5s, and the four pairs of reflecting surfaces 5s are located on four sides of the flat lens 1. Furthermore, if the flat lens 1 is polygonal (having at least five sides), the imaging optical system 100 may include more pairs of reflecting surfaces 5s.

[0059] In the embodiments of the present application, as shown in Figures 10 and 11, the reflecting assembly 5 includes a reflecting mirror 50, and a reflecting surface 5s is provided on the surface of the reflecting mirror 50. The shape of the reflecting mirror 50 may be set as needed. In some embodiments, the reflecting mirror 50 is a flat mirror 51, as shown in Figure 11, and in some embodiments, the reflecting mirror 50 has other shapes. For example, in Figure 22, the reflecting mirror 50 is a prism 52, and two edge surfaces of the reflecting mirror 50 form the reflecting surface 5s.

[0060] 10 to 21, the reflecting assembly 5 includes at least two reflecting mirrors 50, each of which is a plane mirror 51, and the surface of each reflecting mirror 50 facing the central normal L1 forms the reflecting surface 5s. When the reflecting surface 5s is formed using a plane mirror 51, not only is the structure simple, but the shape of the plane mirror 51 is almost the same as the shape of the reflecting surface 5s, and the thickness of the plane mirror 51 can be made thinner, which is advantageous for reducing weight.

[0061] As described above, according to the imaging optical system 100 of the embodiment of the present application, the most direct effect of installing the pair of reflecting surfaces 5s is to expand the field of view of the hollow real image P2 in at least one direction, and depending on the means, this can be expanded up to 180°.

[0062] By installing the reflecting surface 5s, light rays can be fully utilized, and light rays that cannot be irradiated onto the flat lens 1 are reflected and then irradiated onto the flat lens 1, whereby the flat lens 1 focuses the light and images it, thereby increasing the utilization rate of the light rays and increasing the brightness of the aerial real image P2.

[0063] The means of using such a reflecting surface 5s according to the present invention is very simple to provide, and by optimizing the size, shape, and angle α of the reflecting surface 5s with the flat lens 1, the volume of the imaging optical system 100 can be significantly reduced. The installation cost of the reflecting surface 5s is low, and it can be produced on a large scale.

[0064] Hereinafter, the configuration of a display device 1000 according to an embodiment of the present invention will be described with reference to the drawings.

[0065] 22, a display device 1000 according to an embodiment of the present application includes the imaging optical system 100 according to the above-described embodiment of the present application and a display 200 (shown in FIG. 22). The imaging optical system 100 may adopt the configuration of the imaging optical system 100 described in the above-described embodiment, and some of the overlapping content will be omitted here. The display 200 is located on the image source side, and a display screen 210 of the display 200 is installed facing a flat lens 1. In this way, after imaging on the display screen 210, light rays from the display screen 210 pass through the flat lens 1, and can display an aerial real image P2 on the viewing side, the size of which is 1:1 with respect to the size of the image P1.

[0066] 10 to 21 show structural and principle diagrams of display device 1000 in several embodiments. In the principle diagrams of some embodiments, light rays overlap with image P1 and aerial real image P2 on display screen 210, so only a portion of image P1 and a corresponding portion of aerial real image P2 are cut out in the diagrams, as shown in FIGS.

[0067] By installing a pair of reflective surfaces 5s on both sides of the flat lens 1, the reflective surfaces 5s can be used to increase the viewing angle, and in some cases, the reflective surfaces 5s can expand the viewing angle up to 180 degrees. In this way, when an audience member views the aerial real image P2 at the viewing side, the increased viewing angle allows more audience members to see it, making the display device 1000 applicable to public areas for exhibitions and breaking through the usage limitations of the display device 1000. In addition, reflecting light rays using the reflective surfaces 5s can increase the utilization rate of light rays from the light source edge, allowing more light rays to be irradiated onto the aerial real image P2 by the reflective surfaces 5s, which is advantageous for improving imaging quality.

[0068] In some specific embodiments, the display screen 210 is a straight plate screen, and the angle λ between the display screen 210 and the flat lens 1 is an acute angle. When light rays enter the flat lens 1 along the thickness direction, the light rays tend to pass straight through the flat lens 1, significantly reducing the number of light rays that undergo total reflection. The angle λ between the display screen 210 and the flat lens 1 is advantageous in that when most of the light rays emitted from the display screen 210 are incident on the flat lens 1, they form a certain angle with the reflective portions (e.g., reflective portions formed by reflective films) on both sides of the sub-waveguide 101 in the width direction. This allows most of the light rays to be irradiated to the viewing side by total reflection, improving the light utilization rate.

[0069] Specifically, the four sides of the display screen 210 are a near side 211, a far side 212, and two inclined sides 213, and the near side 211 and the far side 212 are opposite sides of the display screen 210, and the near side 211 is located on the side of the display screen 210 closest to the flat lens 1.

[0070] In this case, reflective surfaces 5s may be installed on one, both, or three sides of the display screen 210. Specifically, on the image source side, reflective surfaces 5s may be installed corresponding to the two inclined sides 213 of the display screen 210, respectively, or reflective surfaces 5s may be provided on one side of the display screen 210 corresponding to the far side 212, or reflective surfaces 5s may be provided on both sides of the display screen 210 corresponding to the two inclined sides 213 and on one side of the display screen 210 corresponding to the far side 212. In this way, the reflective surfaces 5s can be used to increase the viewing angle of the display screen 210 in one or two directions.

[0071] In the embodiment of the imaging optical system 100 described above, the reflecting surface 5s can be installed in various configurations, and similarly, the reflecting surface 5s in the display device 1000 can also be installed in various configurations.

[0072] For example, in some alternative embodiments, as shown in Figures 10 to 13, the reflective surface 5s of the corresponding inclined side 213 is a first reflective surface 5s-1 for increasing the viewing angle, and when the display device 1000 has the first reflective surface 5s-1 for increasing the viewing angle, generally, two first reflective surfaces 5s-1 for increasing the viewing angle are installed, and the two first reflective surfaces 5s-1 are installed respectively corresponding to the inclined sides 213 of the flat lens 1. In this way, the two first reflective surfaces 5s-1 for increasing the viewing angle do not interfere with the flat lens 1, and cooperate with each other to increase the viewing angle in the direction in which the two first reflective surfaces 5s-1 for increasing the viewing angle are located.

[0073] Specifically, a projection formed along a direction parallel to the flat lens 1 of the display screen 210 is located entirely within the first viewing angle enhancing reflecting surface 5s-1. In this specification, the mathematical term "projection" is introduced to more clearly describe the shape of the reflecting surface 5s. Here, "a projection formed along a direction parallel to the flat lens 1 of the display screen 210" refers to a figure obtained on the first viewing angle enhancing reflecting surface 5s-1 when a projection line parallel to the flat lens 1 is projected onto the first viewing angle enhancing reflecting surface 5s-1 via the display screen 210. The projections described below also obtain corresponding figures according to this definition.

[0074] Since the projection of the display screen 210 formed along a direction parallel to the flat lens 1 is positioned entirely within the first viewing angle enhancing reflecting surface 5s-1, when the divergence angle of the light source of the display screen 210 is close to 180 degrees, most of the light rays within a 180-degree range in the direction in which the two first viewing angle enhancing reflecting surfaces 5s-1 are located can be irradiated onto the flat lens 1 and the two first viewing angle enhancing reflecting surfaces 5s-1. In this way, the light rays of the aerial real image P2 on the viewing side can be diverged within a 180-degree range, and the viewing angle in the direction in which the two first viewing angle enhancing reflecting surfaces 5s-1 are located can be made approximately 180 degrees. This reduces wasted light rays and increases the brightness of the aerial real image P2.

[0075] Specifically, the first viewing angle enhancing reflecting surface 5s-1 is triangular or trapezoidal, and the projection of the display screen 210 formed along a direction parallel to the flat lens 1 is flush with one side of the first viewing angle enhancing reflecting surface 5s-1. Optionally, when the first viewing angle enhancing reflecting surface 5s-1 is trapezoidal, it can be set to a right-angled trapezoid.

[0076] Since the divergence angle of the light source of the display screen 210 is unlikely to exceed 180 degrees, the portion of the first viewing angle increasing reflecting surface 5s-1 beyond the display screen 210 is hardly exposed to light rays.

[0077] Furthermore, even if the divergence angle of the display screen 210 exceeds 180 degrees, when light rays exceeding 180 degrees are reflected by the reflecting surface 5s, part of the light rays is reflected away from the flat lens 1 and part of the light rays is blocked by the rear surface of the display screen 210, and this part of the light rays is actually ineffective, and the part of the first viewing angle increasing reflecting surface 5s-1 that exceeds the display screen 210 is still wasted.

[0078] Therefore, the projection formed along a direction parallel to the flat lens 1 of the display screen 210 is flush with one side of the first viewing angle increasing reflecting surface 5s-1, thereby reducing the wasted area of ​​the first viewing angle increasing reflecting surface 5s-1.

[0079] 14 to 19, the reflective surface 5s of the corresponding far side 212 is a second reflective surface 5s-2 for increasing the viewing angle. When the display device 1000 has a second reflective surface 5s-2 for increasing the viewing angle, generally, only one second reflective surface 5s-2 for increasing the viewing angle is installed, and it is installed corresponding to the far side 212 of the flat lens 1. Because the distance between the near side 211 of the display screen 210 and the flat lens 1 is short, the space available for installing the reflective surface 5s is limited, so the second reflective surface 5s-2 for increasing the viewing angle is only suitable for installation corresponding to the far side 212 of the display screen 210.

[0080] When the second viewing angle enhancing reflecting surface 5s-2 is provided, the second viewing angle enhancing reflecting surface 5s-2 is rectangular. Because the second viewing angle enhancing reflecting surface 5s-2 is substantially opposite the display screen 210, it is not blocked by other objects, and when the divergence angle of the light source of the display screen 210 is close to 180 degrees, light rays can be efficiently reflected over the entire area of ​​the second viewing angle enhancing reflecting surface 5s-2. In this case, by making the second viewing angle enhancing reflecting surface 5s-2 rectangular, light leakage can be reduced. Furthermore, the rectangular second viewing angle enhancing reflecting surface 5s-2 is not only easy to process, but also very easy to attach and fix.

[0081] In some alternative embodiments, as shown in Figures 20-21, first viewing angle enhancing reflecting surfaces 5s-1 are provided corresponding to two inclined sides 213 of a display screen 210, respectively, and second viewing angle enhancing reflecting surfaces 5s-2 are provided corresponding to a far side 212 of the display screen 210. The first viewing angle enhancing reflecting surface 5s-1 is triangular, and a projection formed along a direction parallel to the flat lens 1 of the display screen 210 is flush with one side of the first viewing angle enhancing reflecting surface 5s-1. A projection formed along a direction parallel to the flat lens 1 of the second viewing angle enhancing reflecting surface 5s-2 is flush with the other side of the first viewing angle enhancing reflecting surface 5s-1. In this way, the two first viewing angle increasing reflecting surfaces 5s-1 and one second viewing angle increasing reflecting surface 5s-2 can be surrounded on three sides of the inclined display screen 210, thereby reflecting as much light as possible onto the flat lens 1, not only increasing the viewing angle in two directions but also maximizing the utilization rate of light and increasing the brightness of the aerial real image P2.

[0082] Hereinafter, with reference to the drawings showing specific embodiments, possible installation forms of the reflecting surface 5s when the display screen 210 is a straight plate screen will be described.

[0083] Example 1

[0084] 10 and 11 show a schematic diagram of the configuration of a display device 1000 in Example 1 and a schematic diagram of the principle of increasing the horizontal viewing angle, and the display device 1000 is a first display device 1000A.

[0085] The first display device 1000A includes a display 200, four reflecting mirrors 50, and a flat lens 1.

[0086] The display 200 is a flat panel display with a light source divergence angle close to 180 degrees. To improve the imaging quality of the aerial real image P2, the angle λ between the display screen 210 of the display 200 and the flat lens 1 is set to 45°. Four reflecting mirrors 50 are divided into two pairs, with two reflecting mirrors 50 of each pair located on the image source side and the viewing side, respectively. Another reflecting surface 5s is formed on the surface of each reflecting mirror 50 facing the central normal L1 of the flat lens 1. In Example 1, all four reflecting surfaces 5s are first viewing angle-enhancing reflecting surfaces 5s-1. On the image source side, two first viewing angle-enhancing reflecting surfaces 5s-1 are located on both the left and right sides of the flat lens 1, and on the viewing side, two first viewing angle-enhancing reflecting surfaces 5s-1 are located on both the left and right sides of the flat lens 1.

[0087] The two reflecting mirrors 50 of the same pair are equal in size and symmetrical to each other with respect to the flat lens 1. The two reflecting mirrors 50 on the image source side are symmetrical with respect to the central normal line L1, and the two reflecting mirrors 50 on the viewing side are symmetrical with respect to the central normal line L1, thereby preventing misalignment at the seams of the images. Assuming that the flat lens 1 is placed horizontally, both sets of reflecting mirrors 50 are placed vertically.

[0088] The shape of the above-mentioned first reflective surface 5s-1 for increasing the viewing angle is a right-angled trapezoid or a triangle, and the first reflective surface 5s-1 for increasing the viewing angle in the first display device 1000A is triangular in shape, which can minimize consumables and the volume of the entire device.

[0089] The first sides of the two triangular reflecting mirrors 50 in each pair are in close contact with the flat lens 1. The second side of the reflecting mirror 50 on the image source side overlaps the object plane (i.e., the plane where the image P1 or display screen 210 is located), and the second side of the reflecting mirror 50 on the viewing side overlaps the image plane (i.e., the plane where the aerial real image P2 is located). The height of the reflecting mirror 50 on the image source side is equal to the height of the display screen 210, and the height of the reflecting mirror 50 on the viewing side is equal to the height of the aerial real image P2. The third side of the reflecting mirror 50 on the image source side consists of a wire connection from the edge of the flat lens 1 to a position at the same height as the display screen 210, and the third side of the reflecting mirror 50 on the viewing side consists of a wire connection from the edge of the flat lens 1 to a position at the same height as the aerial real image P2.

[0090] In Example 1, the principle of the viewing angle expansion is shown in Figure 11. On the image source side, the first viewing angle-enhancing reflecting surfaces 5s-1 located on both sides of the flat lens 1 reflect and reuse light rays within the viewing angle that cannot be incident on the edges of the flat lens 1, allowing these rays to enter the flat lens 1. After emerging, the light is further reflected by the first viewing angle-enhancing reflecting surfaces 5s-1 located on both sides of the flat lens 1 on the viewing side, and finally appears on the image plane. Two pairs of reflecting mirrors 50 are arranged vertically. The angle between the first viewing angle-enhancing reflecting surfaces 5s-1 and the flat lens 1 is α = 90 degrees, η is the viewing angle without the reflecting mirrors 50, β is the range of the viewing angle increase on the left side, and similarly, the range of the viewing angle increase on the right side. The actual viewing angle increase is approximately 180° - η. The increase in horizontal viewing angle is affected by the magnitude of the divergence angle of the light source of the display 200, but is not affected by parameters such as the size of the flat lens 1 and the display 200 and the distance from the display 200 to the flat lens 1.

[0091] According to the means of Example 1, with the above installation, the horizontal viewing angle of the aerial real image P2 is equal to the horizontal viewing angle of the display 200. When the divergence angle of the light source of the display screen 210 is 180 degrees, the horizontal viewing angle of the aerial real image P2 is also approximately 180 degrees.

[0092] Example 2

[0093] 12 and 13 show a schematic diagram of the configuration of a display device 1000 in Example 2 and a schematic diagram of the principle of increasing the horizontal viewing angle, and the display device 1000 is a second display device 1000B.

[0094] The second display device 1000B includes a display 200, four reflecting mirrors 50, and a flat lens 1. As shown in Fig. 12, the configuration layout of the second display device 1000B in Example 2 is almost the same as the configuration layout of the first display device 1000A in Example 1, and a description of the same parts will be omitted here.

[0095] α is the angle between the first viewing angle enhancing reflecting surface 5s-1 and the flat lens 1. The difference from Example 1 is that the angle α between the first viewing angle enhancing reflecting surface 5s-1 and the flat lens 1 in Example 2 is an acute angle, i.e., an angle greater than 0 degrees but less than 90 degrees. η is the viewing angle without the reflecting mirror 50, and β is the range of viewing angle increase on the left side. As with the range of viewing angle increase on the right side, the actual increased viewing angle is approximately equal to 180° - η. The increase in the horizontal viewing angle is affected by the divergence angle of the light source of the display 200. According to the means of Example 2, with the above installation, the horizontal viewing angle of the aerial real image P2 is equal to the horizontal viewing angle of the display 200. When the divergence angle of the light source of the display screen 210 is 180 degrees, the horizontal viewing angle of the aerial real image P2 is also approximately 180 degrees.

[0096] To summarize Examples 1 and 2, both the first display device 1000A and the second display device 1000B can increase the horizontal viewing angle to 180 degrees, with approximately the same viewing angle increase effect and no distortion of the aerial real image P2. Both display devices 1000 are limited in size by the size of the display 200. In the second display device 1000B, the reflecting mirror 50 is arranged diagonally inward, which places a greater restriction on the size of the display 200; the size of the display 200 must not exceed the apex angle distance between the two reflecting mirrors 50 on the left and right.

[0097] Furthermore, in Example 2, all reflecting mirrors 50 are disposed at an angle, and when reflecting mirrors 50 are disposed at an angle, errors are likely to occur in the tilt angle, and imaging deviations are likely to occur when the tilt angles of two reflecting mirrors 50 in a pair are different. In contrast, when reflecting mirrors 50 are disposed vertically, it is easy to control the α angle, and therefore, in comparison, it is easier to realize the means of Example 1 and ensure imaging quality.

[0098] Example 3

[0099] 14 and 15 show a schematic diagram of the configuration of a display device 1000 according to a third embodiment and a schematic diagram of the principle of increasing the vertical viewing angle, and the display device 1000 is a third display device 1000C.

[0100] The third display device 1000C includes a display 200, two reflecting mirrors 50, and a flat lens 1.

[0101] The display 200 is a flat display with a light source divergence angle close to 180 degrees, and in order to improve the imaging quality of the aerial real image P2, the angle λ between the display screen 210 of the display 200 and the flat lens 1 is set to 45°.

[0102] If the vicinity 211 of the display screen 210 is set close to the front side of the flat lens 1, the two reflecting mirrors 50 are installed behind the flat lens 1 and are located on the image source side and the viewing side, respectively.

[0103] The reflecting mirror 50 is rectangular in shape, one side of which is in close contact with the flat lens 1, the two reflecting mirrors 50 are arranged vertically and symmetrically with respect to the flat lens 1, the front surfaces of the two reflecting mirrors 50 form a second reflecting surface 5s-2 for increasing the viewing angle, and the height of the two reflecting mirrors 50 is the same as the height of the display 200 and the aerial real image P2.

[0104] The principle of increasing the vertical viewing angle is shown in Figure 15. α is the angle between the reflecting mirror 50 and the flat lens 1, and is 90 degrees. η is the size of the viewing angle when the reflecting mirror 50 is not added, and β is the range of the actually increased viewing angle of the third display device 1000C. The vertical viewing angle of the aerial real image P2 is determined by both the height of the reflecting mirror 50 and the size of the flat lens 1. Preferably, the angle λ between the display 200 and the flat lens 1 is 45 degrees, so that the sum of η and β is always less than 135 degrees. Only when the size of the flat lens 1 is infinitely large does the sum of η and β approach 135 degrees infinitely.

[0105] Example 4

[0106] 16 to 19 show a schematic diagram of the configuration of a display device 1000 in Example 4 and a schematic diagram of the principle of increasing the vertical viewing angle, and the display device 1000 is a fourth display device 1000D.

[0107] The fourth display device 1000D includes a display 200, two reflecting mirrors 50, and a flat lens 1.

[0108] 17 shows the principle of expanding the viewing angle in the vertical direction when the angle α between the reflecting mirror 50 and the flat lens 1 is α, one side of the reflecting mirror 50 is in close contact with the flat lens 1, and the height of the reflecting mirror 50 is slightly higher than the height of the display 200 and the aerial real image P2. The configuration layout of the fourth display device 1000D in Example 4 and the third display device 1000C in Example 3 are almost the same, with the difference being that the angle α between the reflecting mirror 50 and the flat lens 1 in Example 4 is an acute angle of less than 90 degrees.

[0109] 17, light rays at the viewing angle of the edge of display 200 are reflected by second viewing angle-increasing reflecting surface 5s-2 on the image source side and then re-enter flat lens 1, and the emitted light rays are reflected by second viewing angle-increasing reflecting surface 5s-2 on the viewer side, thereby increasing the viewing angle, where η is the viewing angle without reflecting mirror 50, β is the range of the viewing angle actually increased by fourth display device 1000D, and γ is the angle between reflecting mirror 50 and display 200 or aerial real image P2.

[0110] Figures 17 to 19 show that when the angle α between the reflecting mirror 50 and the flat lens 1 gradually decreases without changing other parameters, the angle between the reflecting mirror 50 and the aerial real image P2 gradually increases, and at this time, a certain change occurs in the increasing range β of the field of view.

[0111] As can be seen from the above, only when γ≧90° does the light ray at the peripheral viewing angle reflect from the image source-side second viewing angle-increasing reflecting surface 5s-2 enter the flat lens 1 close to the display screen 210, and the exiting light ray is further reflected from the viewer-side second viewing angle-increasing reflecting surface 5s-2, thereby expanding the viewing angle range. When γ=90°, the principle is shown in Figure 18. When γ>90°, the principle is shown in Figure 19. When γ=90°, the sum of η and β is already infinitely close to 180 degrees. However, when γ>90°, the requirements for the size of the flat lens 1 for the entire device are greater, but the vertical viewing angle cannot be further increased.

[0112] As described above, when γ=90° and the angle α between the reflecting mirror 50 and the flat lens 1 is 45°, the volume of the imaging device is minimum and the vertical viewing angle is close to 180°.

[0113] Example 5

[0114] 20 and 21 show a schematic diagram of the configuration of a display device 1000 in Example 5 and a schematic diagram of the principle of increasing the vertical viewing angle, and the display device 1000 is a fifth display device 1000E.

[0115] The fifth display device 1000E includes a display 200, four reflecting mirrors 50 for increasing the horizontal viewing angle, two reflecting mirrors 50 for increasing the vertical viewing angle, and one flat lens 1.

[0116] The means of the fifth embodiment corresponds to a combination of the means of the first embodiment and the means of the fourth embodiment.

[0117] The display 200 is a flat display with a light source divergence angle close to 180 degrees, and the angle λ between the display 200 and the flat lens 1 is set to 45° in order to improve the imaging quality of the aerial real image P2.

[0118] By setting the vicinity 211 of the display screen 210 close to the front side of the flat lens 1, three reflecting mirrors 20 are located on the image source side and are respectively located on the left, right and rear sides of the flat lens 1, and three reflecting mirrors 20 are located on the viewing side and are respectively located on the left, right and rear sides of the flat lens 1.

[0119] The reflecting mirrors 50 on both the left and right sides are equal in size and symmetrical to each other with respect to the flat lens 1, and the two reflecting mirrors 50 on the same side are symmetrical with respect to the direction of the central normal L1 of the flat lens 1. The reflecting mirrors 50 on both the left and right sides are both placed vertically and have triangular mirror surfaces, which minimizes the volume of consumables and the entire device.

[0120] The reflecting mirrors 50 on both the left and right sides have a first side that is in close contact with the flat lens 1, a second side that overlaps with the object plane or the image plane, a height of the reflecting mirrors 50 that is equal to the height of the display screen 210 and the aerial real image P2, and a third side that consists of a wire that connects from the edge of the flat lens 1 to a position at the same height as the display screen 210 and the aerial real image P2.

[0121] The reflecting mirrors 50 attached to both the top and bottom rear surfaces of the flat lens 1 are rectangular in shape, with the angle α between the reflecting mirrors 50 and the flat lens 1 being 45 degrees, and one side of the reflecting mirrors being in close contact with the flat lens 1. The height of the reflecting mirrors 50 is approximately the same as the height of the display screen 210 and the aerial real image P2. A side view of this structure is shown in Figure 21.

[0122] By optimizing the size of the reflector 50 and the angle α between it and the flat lens 1, the fifth display device 1000E can make the volume of the device sufficiently small, and yet can display a real aerial image P2 over a viewing angle range of 180 degrees in the horizontal and vertical directions.

[0123] As described above, when the display device 1000 is used in a public place, the display device 1000 can increase the viewing angle in the horizontal direction as follows. A reflector 50 is added to each side of the display 200 and the aerial real image P2. The pair of reflectors 50 are symmetrical with respect to each other with respect to the flat lens 1, and the reflectors 50 on the same side are symmetrical with respect to the central normal L1 of the flat lens 1. The reflector 50 may be disposed diagonally inward or vertically, preferably vertically. This allows for maximum utilization of the flat lens 1 and the use of a larger display 200. The reflector 50 may have a mirror surface shape of a right-angled trapezoid or a triangle, preferably a triangle, which minimizes consumables and the overall volume of the device. The two triangular reflectors 50 of each pair have a first side that is in close contact with the flat lens 1, a second side that overlaps the object plane or the image plane (determined depending on whether the reflector 50 is on the image source side or the viewing side), a height of the reflector 50 equal to the height of the display 200 and the aerial real image P2, and a third side that consists of a wire connecting from the edge of the flat lens 1 to a position at the same height as the display 200 and the aerial real image P2.

[0124] The display device 1000 can be configured to increase the viewing angle in the vertical direction as follows: A reflecting mirror 50 is added to both the top and bottom of the flat lens 1 on one side away from the viewer, and the reflecting mirror 50 is rectangular with one side in close contact with the flat lens 1. The reflecting mirror 50 may be disposed vertically or at an angle inward, preferably at an angle inward, thereby increasing the viewing angle and reducing the volume of the device.

[0125] In the display device 1000 that increases the horizontal viewing angle, the horizontal viewing angle of the aerial real image P2 is related only to the horizontal viewing angle of the display 200, but is not related to the size of the flat lens 1, the display 200, or the distance of the display 200 from the flat lens 1.

[0126] In display device 1000 that increases the vertical viewing angle, the vertical viewing angle of aerial real image P2 is related to the angle between reflecting mirror 50 and flat lens 1, the height of reflecting mirror 50, and the size of flat lens 1.

[0127] It is understood that in the description of this application, terms indicating directions and positional relationships, such as "center," "length," "width," "height," "thickness," "upper," "lower," "left," "right," "vertical," "horizontal," "top," and "bottom," are based on the directions or positions shown in the drawings and are intended merely to facilitate and simplify the description of this application, and do not indicate or imply that the device or element being referred to must have a particular orientation, configuration, or operation in a particular direction, and cannot be considered to limit this application. Furthermore, features qualified as "first" or "second" can expressly or imply the inclusion of one or more of the feature, and in the description of this application, unless otherwise specified, the meaning of "plurality" refers to two or more than two.

[0128] In the description herein, the terms "embodiment" and "example" and the like mean that the specific features, structures, materials, or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the description herein, the terms "exemplary" and "example" do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0129] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is limited by the claims and their equivalents. CROSS-REFERENCE TO RELATED APPLICATIONS

[0130] This application is filed based on a Chinese patent application bearing application number 2021106440414 and filed on June 9, 2021, and claims priority to the above-mentioned Chinese patent application, the entire contents of which are hereby incorporated by reference into this application. [Explanation of symbols]

[0131] 1000, display device; 1000A, first display device, 1000B, second display device, 1000C, third display device, 1000D, fourth display device, 1000E, fifth display device, 100, imaging optical system, 1. Flat lens, 10, optical waveguide array; 11, first optical waveguide array; 12, second optical waveguide array; 101, sub-waveguide, 30, protective cover plate; 31, first cover plate; 32, second cover plate; L1, center normal, 5, Reflective assembly, 50, reflecting mirror, 51, plane mirror, 52, prism, 5s, a reflective surface; 5s-1, a first reflective surface for increasing the viewing angle; 5s-2, a second reflective surface for increasing the viewing angle; 5P, two identical reflective surfaces 5s; 200, display, 210, display screen, 211, near side, 212, far side, 213, inclined side, P1, video; P2, aerial real image.

Claims

1. A display device, an imaging optical system; a display located on the image source side; The display screen of the display is placed facing the flat lens, the imaging optics including a planar lens and a reflecting assembly; the flat lens includes two sets of optical waveguide arrays, each set of which is composed of sub-waveguides arranged in a plurality of rows in a single column and having a rectangular cross section, the two sets of optical waveguide arrays include a first optical waveguide array and a second optical waveguide array, the sub-waveguides of the first optical waveguide array extend along the X direction and form a plurality of rows along the Y direction, the sub-waveguides of the second optical waveguide array extend along the Y direction and form a plurality of rows along the X direction, the first optical waveguide array and the second optical waveguide array are arranged along the Z direction, the X direction, the Y direction, and the Z direction are perpendicular to each other, the flat lens has a central normal, the central normal passes through the center of the flat lens and is parallel to the Z direction, and opposite sides of the flat lens are an image source side and a viewing side, respectively, The reflection assembly has at least one pair of reflection surfaces, and the two reflection surfaces of the pair are located on the image source side and the viewing side, respectively, and all of the reflection surfaces are planar and are arranged toward the central normal, and an angle formed between the reflection surfaces and the flat lens is 90 degrees or less; the angles formed by the two reflecting surfaces of the pair and the flat lens are equal, and the intersections between the two reflecting surfaces of the pair and the flat lens are parallel to each other; The reflection assembly has a plurality of pairs of the reflection surfaces, and the plurality of pairs of the reflection surfaces are arranged along a direction surrounding the central normal. the display screen is a straight plate screen, the angle formed between the display screen and the flat lens is an acute angle, the four sides of the display screen are a near side, a far side and two inclined sides, the near side and the far side are opposite sides of the display screen, and the near side is located on the side of the display screen that is closer to the flat lens, On the image source side, the reflecting surfaces are provided on both sides corresponding to the two inclined sides of the display screen, and the reflecting surface is provided on one side corresponding to the far side of the display screen; the reflective surface corresponding to the inclined edge is a first reflective surface for increasing the viewing angle, and a projection of the display screen formed along a direction parallel to the flat lens is completely located within the first reflective surface for increasing the viewing angle; the reflective surface corresponding to the far side is a second reflective surface for increasing the viewing angle, and the second reflective surface for increasing the viewing angle is rectangular; the first viewing angle-enhancing reflective surface is triangular; a projection of the display screen formed along a direction parallel to the flat lens is flush with one side of the first viewing angle increasing reflecting surface; A display device characterized in that a projection formed along a direction parallel to the flat lens of the second reflecting surface for increasing the viewing angle is flush with the other side of the first reflecting surface for increasing the viewing angle.

2. A display device as described in Claim 1, characterized in that one side of at least one of the reflective surfaces is in close contact with the flat lens.

3. the plurality of pairs of reflecting surfaces include two pairs of the first viewing angle increasing reflecting surfaces located on opposite sides of the central normal line; 2. The display device according to claim 1, wherein in the two pairs of first viewing angle increasing reflective surfaces located on opposite sides of the central normal, the angles formed by each of the reflective surfaces and the flat lens are equal, and the intersections between each of the reflective surfaces and the flat lens are parallel to each other.

4. 2. The display device according to claim 1, wherein the pair of reflecting surfaces are disposed symmetrically with respect to the flat lens.

5. 2. The display device according to claim 1, wherein at least one pair of reflective surfaces of the reflective assembly includes two reflective mirrors, the reflective mirrors being flat mirrors.

Images