A near-eye display device

Abstract

The present invention discloses a near-eye display device, including a display screen and an imaging system. The imaging system includes: a double convex lens, a plane semi-transparent and semi-reflective mirror, and a curved semi-transparent and semi-reflective mirror. The double convex lens is used to magnify the display image of the display screen, the plane semi-transparent and semi-reflective mirror is used to receive the imaging light of the double convex lens and reflect it to the curved semi-transparent and semi-reflective mirror, and the curved semi-transparent and semi-reflective mirror is used to converge the imaging light and reflect it to the position where the human eye is located. The plane semi-transparent and semi-reflective mirror and the curved semi-transparent and semi-reflective mirror have the function of returning light, which is beneficial to reducing the overall volume of the near-eye display device. The double convex lens and the curved semi-transparent and semi-reflective mirror are used in the imaging system, and the three curved surfaces can be optimized to improve the imaging quality of the imaging system, avoid introducing more imaging devices for optimizing parameters, and reduce the number of lenses used as a whole, so as to simplify the structure of the imaging system and reduce the overall weight of the near-eye display device.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a near-eye display device. Background Art

[0002] In recent years, with the continuous development of virtual reality (VR) and augmented reality (AR) technologies, near-eye display products have been widely used in civil fields such as film, television, education, and medical care, instead of being initially used in the military field. Since the image source of near-eye display products is very small, they need to be set at a position close to the human eye so that the image can be clearly imaged within the range observable by the human eye. This brings great difficulty to the design of near-eye display devices.

[0003] Current near-eye display devices are large in size and heavy in weight, which puts great pressure on viewers and often makes them uncomfortable to wear. Simplifying the design of near-eye display devices to reduce their weight will result in poor image quality and a small field of view. Summary of the invention

[0004] The invention provides a display device for.

[0005] The present invention provides a display device, comprising:

[0006] A display screen, used for displaying images;

[0007] An imaging system, located at the light-emitting side of the display screen, for imaging the image displayed on the display screen at the position where the human eye is located;

[0008] Wherein, the imaging system comprises:

[0009] A biconvex lens, located on the light-emitting side of the display screen;

[0010] A plane semi-transparent and semi-reflective mirror, located on a side of the double convex lens away from the display screen;

[0011] A curved semi-transparent and semi-reflective mirror, located on the reflection light path of the flat semi-transparent and semi-reflective mirror;

[0012] The line connecting the optical center of the biconvex lens and the optical center of the plane semi-transparent and semi-reflective mirror intersects with the line connecting the optical center of the plane semi-transparent and semi-reflective mirror and the optical center of the curved semi-transparent and semi-reflective mirror;

[0013] The double convex lens is used to magnify the display image of the display screen, the flat semi-transparent and semi-reflective mirror is used to receive the imaging light of the double convex lens and reflect it toward the curved semi-transparent and semi-reflective mirror, and the curved semi-transparent and semi-reflective mirror is used to converge the imaging light and reflect it toward the position where the human eye is located.

[0014] In a possible implementation, in the above-mentioned display device provided by the present invention, the display screen is located within one focal length of the imaging system.

[0015] In a possible implementation, in the display device provided by the present invention, an exit pupil distance of the imaging system is greater than 18 mm.

[0016] In a possible implementation, in the above-mentioned display device provided by the present invention, the distance between the optical center of the double convex lens and the optical center of the plane semi-transparent and semi-reflective mirror is 7mm-10mm.

[0017] In a possible implementation, in the above-mentioned display device provided by the present invention, the distance between the optical center of the flat semi-transparent and semi-reflective mirror and the optical center of the curved semi-transparent and semi-reflective mirror is 8 mm-11 mm.

[0018] In a possible implementation, in the above-mentioned display device provided by the present invention, the line connecting the optical center of the double convex lens and the optical center of the plane semi-transparent and semi-reflective mirror is perpendicular to the line connecting the optical center of the plane semi-transparent and semi-reflective mirror and the optical center of the curved semi-transparent and semi-reflective mirror.

[0019] In a possible implementation, in the above-mentioned display device provided by the present invention, the two optical surfaces of the double convex lens are spherical surfaces, odd-order aspherical surfaces, even-order aspherical surfaces or free-form surfaces.

[0020] In a possible implementation, in the above display device provided by the present invention, both optical surfaces of the biconvex lens satisfy the following relationship:

[0021]

[0022] Among them, z represents the surface equation of the optical surface, c represents the radius of curvature, k represents the quadratic surface coefficient, r represents the semi-aperture, and α1, α2, α3, α4, and α5 all represent coefficients.

[0023] In a possible implementation, in the above-mentioned display device provided by the present invention, the optical surface of the biconvex lens close to the display screen satisfies:

[0024] r = -49.00863899098125mm;

[0025] k = -95.04941082200814;

[0026] α1=0;

[0027] α2=-1.037904547482000×10-6 ;

[0028] α3=-1.752251362999443×10 -8 ;

[0029] α4=7.636861093444737×10 -11 ;

[0030] α5=-4.351559618685465×10 -13 ;

[0031] The optical surface of the biconvex lens facing away from the display screen satisfies:

[0032] r = 14.05871803442135mm;

[0033] k = -1.367399296176254;

[0034] α1=0;

[0035] α2=-6.706673225527226×10 -5 ;

[0036] α3=8.892596162790160×10 -7 ;

[0037] α4=2.719516289317158×10 -9 ;

[0038] α5=-2.562235658581397×10 -11 .

[0039] In a possible implementation, in the above-mentioned display device provided by the present invention, the two optical surfaces of the curved semi-transparent and semi-reflective mirror are parallel to each other; the two optical surfaces of the curved semi-transparent and semi-reflective mirror are spherical surfaces, odd-order aspherical surfaces, even-order aspherical surfaces or free-form surfaces.

[0040] In a possible implementation, in the above display device provided by the present invention, both optical surfaces of the curved semi-transparent and semi-reflective mirror satisfy the following relationship:

[0041]

[0042] Among them, z represents the surface equation of the optical surface, c represents the radius of curvature, k represents the quadratic surface coefficient, r represents the semi-aperture, and α1, α2, α3, α4, and α5 all represent coefficients.

[0043] In a possible implementation, in the above-mentioned display device provided by the present invention, the optical surface of the curved semi-transparent and semi-reflective mirror satisfies:

[0044] r = -52.20409394488124mm;

[0045] k = -1.604779554699603;

[0046] α1=0;

[0047] α2=-4.991846957838716×10 -6 ;

[0048] α3=2.130618444391338×10 -8 ;

[0049] α4=-1.601068438007377×10 -10 ;

[0050] α5=3.674816411704089×10 -13 .

[0051] In a possible implementation, in the above-mentioned display device provided by the present invention, the surfaces of the plane semi-transparent mirror and the curved semi-transparent mirror are provided with an optical film, and the ratio of light transmission to light reflection of the optical film is 4:6 to 5:5.

[0052] In a possible implementation, in the above-mentioned display device provided by the present invention, the near-eye display device is glasses or a helmet;

[0053] The curved semi-transparent and semi-reflective mirror is reused as the lens of the glasses or helmet.

[0054] The beneficial effects of the present invention are as follows:

[0055] The near-eye display device provided by the present invention comprises: a display screen for displaying an image; an imaging system located on the light-emitting side of the display screen, for imaging the display image of the display screen at the position where the human eye is located; wherein the imaging system comprises: a biconvex lens located on the light-emitting side of the display screen; a plane semi-transparent and semi-reflective mirror located on the side of the biconvex lens away from the display screen; a curved semi-transparent and semi-reflective mirror located on the reflection light path of the plane semi-transparent and semi-reflective mirror; a line connecting the optical center of the biconvex lens and the optical center of the plane semi-transparent and semi-reflective mirror and a line connecting the optical center of the plane semi-transparent and semi-reflective mirror and the optical center of the curved semi-transparent and semi-reflective mirror intersect; the biconvex lens is used to magnify the display image of the display screen, the plane semi-transparent and semi-reflective mirror is used to receive the imaging light of the biconvex lens and reflect it to the curved semi-transparent and semi-reflective mirror, and the curved semi-transparent and semi-reflective mirror is used to converge the imaging light and reflect it to the position where the human eye is located. The plane semi-transparent and semi-reflective mirror and the curved semi-transparent and semi-reflective mirror have the function of folding back the light, so that the light path can be increased by reflection, and the near-eye display device does not need to be designed according to the length of the light path, which is conducive to reducing the overall volume of the near-eye display device. The imaging system uses a double convex lens and a curved semi-transparent and semi-reflective mirror, which can optimize the three curved surfaces to improve the imaging quality of the imaging system, avoid introducing more imaging devices to optimize parameters, and reduce the number of lenses used overall, so as to simplify the structure of the imaging system and reduce the overall weight of the near-eye display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments of the present invention are briefly introduced below. Obviously, the drawings introduced below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0057] Figure 1 A schematic diagram of the structure of a near-eye display device provided by an embodiment of the present invention;

[0058] Figure 2 A field curvature diagram of a near-eye display device provided by an embodiment of the present invention;

[0059] Figure 3 A distortion diagram of a near-eye display device provided by an embodiment of the present invention;

[0060] Figure 4 A grid distortion diagram of a near-eye display device provided by an embodiment of the present invention;

[0061] Figure 5 An optical transfer function curve diagram of a near-eye display device provided by an embodiment of the present invention;

[0062] Figure 6 A schematic diagram of the appearance of a near-eye display device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0063] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described below with reference to the accompanying drawings and examples. However, the exemplary embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concepts of the exemplary embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. The words expressing position and direction described in the present invention are all explained using the accompanying drawings as examples, but changes can be made as needed, and the changes made are all included in the scope of protection of the present invention. The drawings of the present invention are only used to illustrate the relative position relationship and do not represent the true proportions.

[0064] A near-eye display device refers to a display device worn on the user's eyes. For example, a near-eye display device is usually presented in the form of glasses or helmets. A near-eye display device can provide users with AR and VR experiences. Among them, AR near-eye display technology is to superimpose the virtual image generated by the near-eye display device with the real-world real-life image, so that the user can see the final enhanced real-life image on the screen. VR near-eye display technology displays the images of the left and right eyes on the near-eye displays corresponding to the left and right eyes respectively. After the left and right eyes obtain different image information, they can synthesize stereoscopic vision in the brain.

[0065] Current near-eye display devices still have problems of large size, heavy weight and poor imaging quality. An embodiment of the present invention provides a near-eye display device to reduce the weight of the entire device and improve the imaging quality.

[0066] Figure 1 A schematic diagram of the structure of a near-eye display device provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the near-eye display device provided by the embodiment of the present invention includes:

[0067] The display screen 100 is used to display images.

[0068] The display screen 100 is used as an image source to display an image. The display screen 100 may be a liquid crystal display screen or an organic light emitting diode display screen, which is not limited here. The display screen 100 in the near-eye display device is usually small in size and is installed in the near-eye display device. In a specific implementation, a higher-resolution display screen may be used to provide a more delicate display image.

[0069] The imaging system 200 is located at the light-emitting side of the display screen 100 and is used to image the display image of the display screen 100 at the position where the human eye is located.

[0070] The imaging system 200, which is indispensable in the near-eye display device, is located on the light-emitting side of the display screen 100, and is used to image the display image of the display screen 100 at the position where the human eye is located. The near-eye display device may include two display screens 100 and two imaging systems 200, corresponding to the left eye and the right eye respectively. The images displayed by the display screens corresponding to the left eye and the right eye may have some information differences, so that after the left eye and the right eye receive the corresponding images, the images can be synthesized in the brain to produce a three-dimensional visual effect.

[0071] Specifically, Figure 1 As shown, the imaging system 200 includes:

[0072] A double convex lens 21, located at the light-emitting side of the display screen 100;

[0073] A plane semi-transparent and semi-reflective mirror 22 is located on a side of the double convex lens 21 away from the display screen 100;

[0074] The curved semi-transparent and semi-reflective mirror 23 is located on the reflection light path of the flat semi-transparent and semi-reflective mirror 22 .

[0075] The line connecting the optical center of the biconvex lens 21 and the optical center of the plane semi-transparent mirror 22 intersects with the line connecting the optical center of the plane semi-transparent mirror 22 and the optical center of the curved semi-transparent mirror 23 .

[0076] The light emitted from the display screen 100 is first incident on the double convex lens 21, which is used to magnify the displayed image. After passing through the double convex lens 21, the light is incident on the plane semi-transparent and semi-reflective mirror 22. The plane semi-transparent and semi-reflective mirror 22 reflects the light toward the curved semi-transparent and semi-reflective mirror 23. Then, after being reflected by the curved semi-transparent and semi-reflective mirror 23, the light is reflected to one side of the plane semi-transparent and semi-reflective mirror 22 and converged, and finally passes through the plane semi-transparent and semi-reflective mirror 23 and is incident on the position s where the human eye is located.

[0077] The flat semi-transparent and semi-reflective mirror 22 and the curved semi-transparent and semi-reflective mirror 23 have the function of reflecting light, so that the light path can be extended by reflection, without the need to design the near-eye display device according to the length of the light path, which is beneficial to reducing the overall volume of the near-eye display device.

[0078] The imaging system 200 uses a double convex lens 22 and a curved semi-transparent and semi-reflective mirror 23, so that the three curved surfaces can be optimized to improve the imaging quality of the imaging system, avoid introducing more imaging devices for the purpose of optimizing parameters, and reduce the number of lenses used overall, so as to simplify the structure of the imaging system and reduce the overall weight of the near-eye display device.

[0079] In a specific implementation, the display screen 100 may be placed within one focal length of the imaging system 200 .

[0080] In the near-eye display device, the display screen 100 is relatively small in size, and the human eye cannot directly observe when a relatively small display screen is used to display rich image details. Therefore, the display screen 100 can be placed within one focal length of the imaging system 200, so that the imaging system can form an upright and enlarged virtual image, and enlarge the display image of the display screen 100, so that the human eye can observe the details in the display image.

[0081] The distance between the display screen 100 and the imaging system 200 can also be adjusted to affect the distance of the imaging position. When the distance between the display screen 100 and the imaging system 200 is reduced, the image seen by the human eye is farther away; when the distance between the display screen 100 and the imaging system 200 is increased, the image seen by the human eye is closer. Therefore, in practical applications, the imaging position can be adjusted by adjusting the distance between the display screen 100 and the imaging system 200 to find the best imaging position.

[0082] like Figure 1 As shown, the distance between the imaging position s and the optical center of the plane semi-transparent and semi-reflective mirror 22 is the exit pupil distance of the imaging system 200. In the embodiment of the present invention, the exit pupil distance of the imaging system 200 is greater than 18 mm. This can prevent the human eye from being too close to the near-eye display device, making it more convenient for the audience to wear and optimizing the design.

[0083] In specific implementation, Figure 1 As shown, the line connecting the optical center of the biconvex lens 21 and the optical center of the plane semi-transparent mirror 22 is perpendicular to the line connecting the optical center of the plane semi-transparent mirror 22 and the optical center of the curved semi-transparent mirror 23. Figure 1 Taking the structure shown as an example, when the display surface of the display screen 100 is vertically downward, the plane semi-transparent and semi-reflective mirror 22 can be set at an angle of 45 degrees to the horizontal plane, and the curved semi-transparent and semi-reflective mirror 23 can be set perpendicular to the horizontal plane, so that the line connecting the optical center of the double convex lens 21 and the optical center of the plane semi-transparent and semi-reflective mirror 22 is perpendicular to the line connecting the optical center of the plane semi-transparent and semi-reflective mirror 22 and the optical center of the curved semi-transparent and semi-reflective mirror 23, so as to simplify the design of the optical path.

[0084] The distance between the optical center of the lenticular lens 21 and the optical center of the plane semi-transparent mirror 22 refers to the distance between the center point of the optical surface of the lenticular lens 21 facing away from the display screen 100 and the center point of the optical surface of the plane semi-transparent mirror 22 facing the lenticular lens 21. In the embodiment of the present invention, the distance between the optical center of the lenticular lens 21 and the optical center of the plane semi-transparent mirror 22 is 7mm-10mm, and when the value is 8.7mm-8.8mm, the imaging effect is better.

[0085] like Figure 1As shown, the distance between the optical center of the plane semi-transparent mirror 22 and the optical center of the curved semi-transparent mirror 23 refers to the distance between the center point of the optical surface of the plane semi-transparent mirror 22 facing the curved semi-transparent mirror 23 and the center point of the optical surface of the curved semi-transparent mirror 23 facing the plane semi-transparent mirror 22. In the embodiment of the present invention, the distance between the optical center of the plane semi-transparent mirror 22 and the optical center of the curved semi-transparent mirror 23 is 8mm-11mm, and when the value is 9.7mm-9.8mm, the imaging effect is better.

[0086] The surface shape of each lens in the imaging system and the distance between each lens will affect the imaging quality. The embodiment of the present invention takes into account multiple factors such as field curvature, distortion and optical transfer function, and determines the spacing between each optical component and the surface shape of each optical component.

[0087] Specifically, the two optical surfaces of the biconvex lens 21 in the embodiment of the present invention can be selected from any one of spherical surface, odd-order aspherical surface, even-order aspherical surface or free-form surface. As the aspherical lens has more comprehensive parameters that can be optimized than the spherical lens, it has better imaging quality.

[0088] In a specific implementation, the two optical surfaces of the biconvex lens 21 can be designed as any one of odd-order aspheric surfaces, even-order aspheric surfaces, or free-form surfaces. The odd-order aspheric surface is an asymmetric aspheric surface, and the even-order aspheric surface is a symmetric aspheric surface. Considering the difficulty of processing, the embodiment of the present invention can design the two optical surfaces of the biconvex lens 21 as even-order aspheric surfaces.

[0089] Specifically, both optical surfaces of the biconvex lens 21 can satisfy the following relationship:

[0090]

[0091] Among them, z represents the surface equation of the optical surface, c represents the radius of curvature, k represents the quadratic surface coefficient, r represents the semi-aperture, and α1, α2, α3, α4, and α5 all represent coefficients.

[0092] The value of k can affect the shape of the optical surface. α1, α2, α3, α4, and α5 are coefficients of high-order terms. The more high-order terms there are, the more sophisticated the design is. When performing optical design, the imaging quality of the biconvex lens can be optimized by increasing the number of high-order terms.

[0093] Furthermore, when the optical surface of the double convex lens 21 close to the display screen 100 satisfies the above formula, the values ​​of the parameters are as follows:

[0094] r = -49.00863899098125mm;

[0095] k = -95.04941082200814;

[0096] α1=0;

[0097] α2=-1.037904547482000×10 -6 ;

[0098] α3=-1.752251362999443×10 -8 ;

[0099] α4=7.636861093444737×10 -11 ;

[0100] α5=-4.351559618685465×10 -13 .

[0101] When the optical surface of the double convex lens 21 facing away from the display screen 100 satisfies the above formula, the values ​​of the parameters are as follows:

[0102] r = 14.05871803442135mm;

[0103] k = -1.367399296176254;

[0104] α1=0;

[0105] α2=-6.706673225527226×10 -5 ;

[0106] α3=8.892596162790160×10 -7 ;

[0107] α4=2.719516289317158×10 -9 ;

[0108] α5=-2.562235658581397×10 -11 .

[0109] Thus, the optical design of the two optical surfaces of the biconvex lens 21 is completed.

[0110] The two optical surfaces of the curved semi-transparent and semi-reflective mirror 23 in the embodiment of the present invention are parallel to each other; the two optical surfaces of the curved semi-transparent and semi-reflective mirror 23 can be any one of a spherical surface, an odd-order aspherical surface, an even-order aspherical surface or a free-form surface. As the aspherical lens has more comprehensive parameters that can be optimized than the spherical lens, it has better imaging quality.

[0111] In a specific implementation, the two optical surfaces of the curved semi-transparent and semi-reflective mirror 23 can be designed as any one of odd-order aspheric surfaces, even-order aspheric surfaces, or free-form surfaces. The odd-order aspheric surface is an asymmetric aspheric surface, and the even-order aspheric surface is a symmetric aspheric surface. Considering the difficulty of processing, the embodiment of the present invention can design the two optical surfaces of the curved semi-transparent and semi-reflective mirror 23 as even-order aspheric surfaces.

[0112] Specifically, both optical surfaces of the curved semi-transparent and semi-reflective mirror 23 can satisfy the following relationship:

[0113]

[0114] Among them, z represents the surface equation of the optical surface, c represents the radius of curvature, k represents the quadratic surface coefficient, r represents the semi-aperture, and α1, α2, α3, α4, and α5 all represent coefficients.

[0115] The value of k can affect the shape of the optical surface. α1, α2, α3, α4, and α5 are coefficients of high-order terms. The more high-order terms there are, the more sophisticated the design is. When performing optical design, the imaging quality of the curved semi-transparent and semi-reflective mirror can be optimized by increasing the number of high-order terms.

[0116] Furthermore, when the optical surface of the curved semi-transparent and semi-reflective mirror 23 satisfies the above formula, the values ​​of the parameters are as follows:

[0117] r = -52.20409394488124mm;

[0118] k = -1.604779554699603;

[0119] α1=0;

[0120] α2=-4.991846957838716×10 -6 ;

[0121] α3=2.130618444391338×10 -8 ;

[0122] α4=-1.601068438007377×10 -10 ;

[0123] α5=3.674816411704089×10 -13 .

[0124] Thus, the optical design of the two optical surfaces of the curved semi-transparent and semi-reflective mirror 23 is completed.

[0125] The parameter values ​​of the optical surfaces of the biconvex lens 21 and the curved semi-transparent and semi-reflective mirror 23 can be optimized according to the final performance of the imaging system in terms of field curvature, distortion, and optical transfer function. The surface shapes of the biconvex lens 21 and the curved semi-transparent and semi-reflective mirror 23 and the spacing between the optical components will affect the imaging quality of the imaging system. Many factors need to be considered comprehensively when performing optical design.

[0126] When performing optical design, the biconvex lens 21 and the curved semi-transparent and semi-reflective mirror 23 may also be selected as odd-order aspheric surfaces or free-form surfaces. The embodiment of the present invention only uses the implementation scheme of even-order aspheric surfaces as an example, and does not limit the specific surface shapes of the biconvex lens 21 and the curved semi-transparent and semi-reflective mirror 23. When the biconvex lens 21 and the curved semi-transparent and semi-reflective mirror 23 are selected as other types of surface shapes, the corresponding parameters should be reset.

[0127] The embodiment of the present invention also provides imaging performance of the imaging system 200 in terms of field curvature, distortion, and optical transfer function when each optical component in the imaging system meets the above conditions.

[0128] Figure 2 A field curvature diagram of a near-eye display device provided by an embodiment of the present invention, wherein the horizontal axis represents the field curvature amount and the vertical axis represents the field of view height. The closer the field curvature amount of the imaging system at each field of view height is to 0, the better the imaging effect. The field curvature diagram shows the field curvature amount in the sagittal direction and the meridional direction, wherein the dotted line represents the field curvature amount in the sagittal direction, the solid line represents the field curvature amount in the meridional direction, and different grayscales represent the field curvature amount of light of different wavelengths. Figure 2 As shown, the field curvature of the imaging system 200 provided by the embodiment of the present invention is controlled within ±0.1 after parameter optimization, the field curvature is small, and the imaging effect is good.

[0129] Figure 3 This is a distortion diagram of a near-eye display device provided by an embodiment of the present invention, wherein the horizontal axis represents the distortion amount and the vertical axis represents the field of view height. The closer the field curvature of the imaging system is to 0 at each field of view height, the better the imaging effect. Different grayscales in the distortion diagram represent the distortion amounts of light of different wavelengths. Figure 3 As shown, the imaging system 200 provided by the embodiment of the present invention has a distortion amount less than 2% after parameter optimization, which means the distortion amount is small and the imaging effect is good.

[0130] Figure 4 This is a grid distortion diagram of a near-eye display device provided by an embodiment of the present invention, where "×" represents a real imaging point and "·" represents an ideal imaging point. Figure 3 It can be seen that after parameter optimization, the imaging system 200 provided by the embodiment of the present invention has a small position difference between the actual imaging point and the ideal imaging point, a network distortion is less than 1.4%, a small distortion amount, and a good imaging effect.

[0131] Figure 5 This is an optical transfer function curve diagram of a near-eye display device provided in an embodiment of the present invention, wherein the abscissa represents the spatial frequency and the ordinate represents the modulation transfer function (MTF) value, which is an important parameter of the optical system. Figure 5 The top curve represents the diffraction limit when the field of view angle is 0. The closer the MTF value at different field of view angles is to the top curve, the better the imaging effect of the imaging system. The optical transfer function curve diagram shows the MTF curves in the sagittal direction and the meridional direction, where the dotted line represents the MTF curve in the sagittal direction, the solid line represents the MTF curve in the meridional direction, and different grayscales represent the MTF curves of light of different wavelengths. Figure 5 As shown, after parameter optimization, the optical transfer function of the imaging system 200 provided by the embodiment of the present invention is greater than 0.3 at 31lp / mm for the whole field of view, and greater than 0.1 at 62lp / mm for the whole field of view, and has better imaging performance.

[0132] In the specific processing process, the double convex lens 21, the plane semi-transparent and semi-reflective mirror 22 and the curved semi-transparent and semi-reflective mirror 23 can be made of optical glass, resin, plastic and other materials, which are not limited here.

[0133] Among them, the surfaces of the plane semi-transparent mirror 22 and the curved semi-transparent mirror 23 are provided with optical films, and the ratio of light transmission to light reflection of the optical films is 4:6 to 5:5. The optical film in the embodiment of the present invention utilizes the thin film interference principle, and by adjusting the number of layers of the optical film, the refractive index of the material, the thickness and other parameters, it has the function of transmission or reflection. Adjusting the above parameters can also control the ratio of light transmission to light reflection of the optical film.

[0134] In practical applications, the reflected light of the plane semi-transparent mirror 22 is used for imaging, but the reflected light of the curved semi-transparent mirror 23 finally passes through the plane semi-transparent mirror 22 before entering the human eye. Therefore, the transmittance and reflectance of the plane semi-transparent mirror 22 are equivalent, and neither too much reflected light nor too much transmitted light is lost. When applied to the VR field, the reflectance of the curved semi-transparent mirror 23 can be increased so that more light can be used for imaging; when applied to the AR field, the ambient light needs to pass through the curved semi-transparent mirror 23 to participate in the synthetic image. At this time, the transmittance and reflectance of the curved semi-transparent mirror 23 need to be reasonably set. In the embodiment of the present invention, the ratio of light transmission and light reflection of the optical film on the surface of the plane semi-transparent mirror 22 and the curved semi-transparent mirror 23 can be controlled in the range of 4:6 to 5:5, with a good imaging effect.

[0135] The above-mentioned near-eye display device provided in the embodiment of the present invention can be glasses or helmets. In this case, the curved semi-transparent and semi-reflective mirrors 23 can be reused as lenses of the glasses or helmets, thereby reducing the number of lenses used by the near-eye display device. When the near-eye display device is glasses, its appearance can be seen in Figure 6 .

[0136] The near-eye display device provided by an embodiment of the present invention includes: a display screen for displaying an image; an imaging system, located on the light-emitting side of the display screen, for imaging the displayed image of the display screen at the position where the human eye is located; wherein the imaging system includes: a double convex lens, located on the light-emitting side of the display screen; a plane semi-transparent and semi-reflective mirror, located on the side of the double convex lens away from the display screen; a curved semi-transparent and semi-reflective mirror, located on the reflection light path of the plane semi-transparent and semi-reflective mirror; a line connecting the optical center of the double convex lens and the optical center of the plane semi-transparent and semi-reflective mirror intersects with a line connecting the optical center of the plane semi-transparent and semi-reflective mirror and the optical center of the curved semi-transparent and semi-reflective mirror; the double convex lens is used to magnify the displayed image of the display screen, the plane semi-transparent and semi-reflective mirror is used to receive the imaging light of the double convex lens and reflect it toward the curved semi-transparent and semi-reflective mirror, and the curved semi-transparent and semi-reflective mirror is used to converge the imaging light and reflect it toward the position where the human eye is located. The flat semi-transparent and semi-reflective mirrors and the curved semi-transparent and semi-reflective mirrors have the function of refracting light, so that the light path can be extended by reflection, without the need to design the near-eye display device according to the length of the light path, which is conducive to reducing the overall volume of the near-eye display device. The imaging system uses a double convex lens and a curved semi-transparent and semi-reflective mirror, so that the three curved surfaces can be optimized to improve the imaging quality of the imaging system, avoid introducing more imaging devices to optimize parameters, and reduce the number of lenses used as a whole, so as to simplify the structure of the imaging system and reduce the overall weight of the near-eye display device.

[0137] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0138] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A near-eye display device, characterized in that: include: A display screen, used to display images; the display screen is a liquid crystal display screen or an organic light emitting diode display screen; An imaging system, located at the light-emitting side of the display screen, for imaging the image displayed on the display screen at the position where the human eye is located; Wherein, the imaging system comprises: A biconvex lens, located on the light-emitting side of the display screen; A plane semi-transparent and semi-reflective mirror, located on a side of the double convex lens away from the display screen; A curved semi-transparent and semi-reflective mirror, located on the reflection light path of the flat semi-transparent and semi-reflective mirror; The line connecting the optical center of the biconvex lens and the optical center of the plane semi-transparent and semi-reflective mirror intersects with the line connecting the optical center of the plane semi-transparent and semi-reflective mirror and the optical center of the curved semi-transparent and semi-reflective mirror; The double convex lens is used to magnify the display image of the display screen, the flat semi-transparent and semi-reflective mirror is used to receive the imaging light of the double convex lens and reflect it to the curved semi-transparent and semi-reflective mirror, and the curved semi-transparent and semi-reflective mirror is used to converge the imaging light and reflect it to the position where the human eye is located; The two optical surfaces of the biconvex lens satisfy the following relationship: Among them, z represents the surface equation of the optical surface, c represents the radius of curvature, k represents the quadratic surface coefficient, r represents the semi-aperture, and α1, α2, α3, α4, and α5 all represent coefficients; The optical surface of the biconvex lens close to the display screen satisfies: r = -49.00863899098125mm; k＝-95.04941082200814； α1＝0； α2＝-1.037904547482000×10 -6 ； α3＝-1.752251362999443×10 -8 ； α4＝7.636861093444737×10 -11 ； α5＝-4.351559618685465×10 -13 ； The optical surface of the biconvex lens facing away from the display screen satisfies: r = 14.05871803442135mm; k＝-1.367399296176254； α1＝0； α2＝-6.706673225527226×10 -5 ； α3＝8.892596162790160×10 -7 ； α4＝2.719516289317158×10 -9 ； α5＝-2.562235658581397×10 -11 。 2. The near-eye display device according to claim 1, wherein: The display screen is located within one focal length of the imaging system.

3. The near-eye display device according to claim 1, wherein: The pupil distance of the imaging system is greater than 18 mm.

4. The near-eye display device according to claim 1, wherein: The distance between the optical center of the biconvex lens and the optical center of the plane semi-transparent and semi-reflective mirror is 7mm-10mm.

5. The near-eye display device according to claim 4, characterized in that: The distance between the optical center of the plane semi-transparent and semi-reflective mirror and the optical center of the curved semi-transparent and semi-reflective mirror is 8mm-11mm.

6. The near-eye display device according to claim 1, wherein: The line connecting the optical center of the biconvex lens and the optical center of the plane semi-transparent and semi-reflective mirror is perpendicular to the line connecting the optical center of the plane semi-transparent and semi-reflective mirror and the optical center of the curved semi-transparent and semi-reflective mirror.

7. The near-eye display device according to claim 1, wherein: The two optical surfaces of the curved semi-transparent and semi-reflective mirror are parallel to each other; the two optical surfaces of the curved semi-transparent and semi-reflective mirror are spherical surfaces, odd-order aspherical surfaces, even-order aspherical surfaces or free-form surfaces.

8. The near-eye display device according to claim 7, wherein: The two optical surfaces of the curved semi-transparent and semi-reflective mirror both satisfy the following relationship: Among them, z1 represents the surface equation of the optical surface, c1 represents the radius of curvature, k1 represents the quadratic surface coefficient, r1 represents the semi-aperture, and b1, b2, b3, b4, and b5 all represent coefficients.

9. The near-eye display device according to claim 8, characterized in that: The optical surface of the curved semi-transparent and semi-reflective mirror satisfies: r1 = -52.20409394488124mm; k1＝-1.604779554699603； b1＝0； b2＝-4.991846957838716×10 -6 ； b3＝2.130618444391338×10 -8 ； b4＝-1.601068438007377×10 -10 ； b5＝3.674816411704089×10 -13 。 10. The near-eye display device according to any one of claims 1 to 9, characterized in that: Optical films are provided on the surfaces of the plane semi-transparent mirror and the curved semi-transparent mirror, and the ratio of light transmission to light reflection of the optical films is 4:6 to 5:

5.

11. The near-eye display device according to any one of claims 1 to 9, characterized in that: The near-eye display device is glasses or a helmet; The curved semi-transparent and semi-reflective mirror is reused as the lens of the glasses or helmet.

Images