Eyepiece lens and near-eye display module

Abstract

The present invention discloses an eyepiece lens and a near-eye display module. The eyepiece lens includes a plurality of lens groups coaxially arranged in sequence from the object side to the image side. An image source is arranged on the object side for providing an optical signal for the eyepiece lens. The X direction is defined as the direction corresponding to the long side of the image source pixel size, the Y direction is defined as the direction corresponding to the short side of the image source pixel size, the Z direction is defined as the direction corresponding to the length of the eyepiece lens, and the three directions XYZ are perpendicular to each other. The effective focal length ratio of the eyepiece lens in the XZ direction and the YZ direction is determined according to the aspect ratio of the pixel size of the image source; and the effective focal length ratio of the eyepiece lens in the XZ direction and the YZ direction satisfies: 0.5≤fx / fy≤1. The eyepiece lens of the present invention has different effective focal length values ​​in the XZ direction and the YZ direction, thereby reducing the size of the entire eyepiece lens.

Description

Technical Field

[0001] The present invention relates to the technical field of optical near-eye display, and in particular to an eyepiece lens and a near-eye display module. Background Art

[0002] Near-eye display optical system is also called helmet display. Based on augmented reality, near-eye display system can superimpose virtual images while people are watching the surrounding environment, so as to obtain more visual information. Near-eye display helmet display was first used in the military field. With the advancement of science and technology and the development of society, it has gradually expanded to various fields such as industry, entertainment, and medical treatment. People are also doing more and more research on near-eye display.

[0003] Since the waveguide has the advantages of being thin and light in appearance and closer in size to ordinary glasses, the near-eye display system based on waveguide has become one of the mainstream solutions for development. Both geometric optical waveguides and diffraction optical waveguides use the principle of total reflection of light in the waveguide, which theoretically will not affect the display quality of the near-eye display system. As an important component of the near-eye display system, the imaging quality of the eyepiece lens directly affects the display effect of the overall near-eye display system, and its size also directly affects the wearing comfort of the near-eye display system. Therefore, an eyepiece lens with small size, light weight and good imaging quality is needed for use in the near-eye display system.

[0004] Conventional eyepiece lenses based on one-dimensional array waveguide design have a large screen size of the image source, and the single pixel of the image source is generally square. The display screen ratio is usually 16:9 or 4:3, that is, the length is greater than the width. This will result in a large size of the eyepiece lens, especially a large size corresponding to the long side of the screen, which causes the eyepiece lens of the near-eye display to interfere with the side of the human face, reducing wearing comfort. Summary of the invention

[0005] Technical purpose: In view of the defects in the prior art, the present invention discloses an eyepiece lens and a near-eye display module. The eyepiece lens has different effective focal length values ​​in the XZ direction and the YZ direction, thereby reducing the size of the entire eyepiece lens.

[0006] Technical solution: In order to achieve the above technical objectives, the present invention adopts the following technical solution.

[0007] An eyepiece lens comprises a plurality of lens groups coaxially arranged in sequence from an object side to an image side, an image source is arranged on the object side for providing an optical signal for the eyepiece lens; an X direction is defined as a direction corresponding to a long side of a pixel size of the image source, a Y direction is defined as a direction corresponding to a short side of a pixel size of the image source, a Z direction is defined as a direction corresponding to a length of the eyepiece lens, and the three directions X, Y, and Z are perpendicular to each other; an effective focal length ratio of the eyepiece lens in the XZ direction and the YZ direction is determined according to an aspect ratio of a pixel size of the image source; and an effective focal length ratio of the eyepiece lens in the XZ direction and the YZ direction satisfies: 0.5 ≤ fx / fy ≤ 1.

[0008] Preferably, the eyepiece lens comprises a first group of lenses, a second group of lenses and a third group of lenses coaxially arranged in sequence from the object side to the image side; the first group of lenses and the third group of lenses have non-rotationally symmetric surface shapes, and the second group of lenses has a rotationally symmetric surface shape.

[0009] Preferably, the second group of lenses includes a second lens and a third lens, and the second lens and the third lens form a doublet lens.

[0010] Preferably, the effective focal length of the eyepiece lens in the YZ direction and the effective focal length of the second lens satisfy: -0.7≤ f2 / fy ≤-0.4, where f2 is the effective focal length of the second lens.

[0011] Preferably, the effective focal length of the eyepiece lens in the YZ direction and the effective focal length of the third lens satisfy: 0.7≤ f3 / fy ≤1, where f3 is the effective focal length of the third lens.

[0012] Preferably, the first group of lenses includes a first lens, and an effective focal length f1x of the first lens along the XZ direction and an effective focal length f1y of the first lens along the YZ direction satisfy: 0.1≤ f1x / f1y≤0.6.

[0013] Preferably, the third group of lenses includes a fourth lens, and an effective focal length f4x of the fourth lens along the XZ direction and an effective focal length f4y of the fourth lens along the YZ direction satisfy: 0.7≤f4x / f4y≤1.3.

[0014] A near-eye display module comprises an image source, an eyepiece lens and a waveguide, wherein the eyepiece lens is any one of the above-mentioned eyepiece lenses; the image source is used to emit a light signal, wherein the light signal includes image information; the eyepiece lens is arranged in the light emitting direction of the image source, and is used to modulate the light signal; the waveguide is arranged on the side of the eyepiece lens away from the image source, and is used to transmit the modulated light signal.

[0015] Preferably, the image source is a liquid crystal on silicon display, an organic light emitting diode or a micro light emitting diode.

[0016] Preferably, the waveguide sheet is a geometric optical waveguide or a diffraction optical waveguide.

[0017] Beneficial effect: The eyepiece lens of the present invention has different effective focal length values ​​in the XZ direction and the YZ direction, that is, it has different magnifications for the long side and the short side of the image source display screen, which makes the single-pixel design of the image source no longer limited to the conventional square with an aspect ratio of 1:1, but can be designed as a rectangle with an aspect ratio not equal to 1:1. While maintaining the same high resolution, the overall size of the image source can be made smaller, thereby reducing the size of the entire eyepiece lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of an eyepiece lens in the YZ direction provided in Example 1;

[0019] Figure 2 A schematic diagram of the structure of an eyepiece lens in the XZ direction provided in Example 1;

[0020] Figure 3 An original image of an image source before the near-eye display of an eyepiece lens provided in the first embodiment;

[0021] Figure 4 A projected display image after near-eye display by an eyepiece lens provided in Embodiment 1;

[0022] Figure 5 A schematic diagram of the structure and dimensions of an eyepiece lens designed in the prior art with the same parameters and specifications as those of the first embodiment;

[0023] Figure 6 A schematic diagram of the structure and dimensions of an eyepiece lens provided in Example 1;

[0024] Figure 7 A schematic diagram of the structure of an eyepiece lens in the YZ direction provided in Example 2;

[0025] Figure 8 A schematic diagram of the structure of an eyepiece lens in the XZ direction provided in Example 2;

[0026] Fig. 9 An original image of an image source before the near-eye display of an eyepiece lens provided in the second embodiment;

[0027] Fig.10 A projected display image after near-eye display by an eyepiece lens provided in Embodiment 2;

[0028] Fig.11 A schematic diagram of the structure and dimensions of an eyepiece lens designed in the prior art with the same parameters and specifications as those of the second embodiment;

[0029] Fig.12A schematic diagram of the structure and dimensions of an eyepiece lens provided in Example 2;

[0030] Fig.13 This is a schematic diagram of a square pixel image source structure with an aspect ratio of 1:1 in the present invention;

[0031] Fig.14 It is a schematic diagram of the structure of a rectangular pixel image source with an aspect ratio not equal to 1:1 in the present invention;

[0032] Fig.15 It is a schematic diagram of the structure of the near-eye display module in the present invention;

[0033] Among them, 00 is the image source, 01 is the eyepiece lens, 02 is the waveguide plate; 10 is the first lens, 20 is the second lens, 30 is the third lens, and 40 is the fourth lens. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] An eyepiece lens of the present invention comprises a plurality of lens groups coaxially arranged in sequence from an object side to an image side, an image source is arranged on the object side for providing an optical signal for the eyepiece lens; an X direction is defined as a direction corresponding to a long side of a pixel size of the image source, a Y direction is defined as a direction corresponding to a short side of a pixel size of the image source, and a Z direction is defined as a direction corresponding to a length of the eyepiece lens, and the three directions XYZ are perpendicular to each other; an effective focal length ratio of the eyepiece lens in the XZ direction and in the YZ direction is determined according to an aspect ratio of a pixel size of the image source, that is, an effective focal length of the eyepiece lens in the XZ direction is fx, and an effective focal length in the YZ direction is fy, and fx / fy=a / b; a is a pixel size length of the image source, and b is a pixel size width;

[0036] According to the eyepiece lens provided in the present invention, a single pixel of the image source is no longer limited to a conventional square with an aspect ratio of 1:1, but can be designed as a rectangle with an aspect ratio not equal to 1:1, which can effectively reduce the size of the image source, and thus reduce the size of the eyepiece lens in the width direction. In the simulation verification of some embodiments of the present invention, the size of the eyepiece lens in the width direction is reduced by at least 8%.

[0037] In some embodiments of the present invention, the eyepiece lens includes a first lens group, a second lens group, and a third lens group coaxially arranged in sequence from the object side to the image side; the first lens group includes a first lens 10, the second lens group includes a second lens 20 and a third lens 30, and the third lens group includes a fourth lens 40;

[0038] Among them, the first lens and the fourth lens have non-rotationally symmetric surface shapes, different surface shapes and different optical focal powers in the XZ direction and the YZ direction; the surface shapes of the first lens and the fourth lens include: biconical surface, polynomial, extended polynomial, Zernike standard sag, etc.

[0039] The second lens and the third lens form a doublet lens, and the surface shape is a conventional rotationally symmetrical surface shape, that is, a spherical surface or an aspherical surface; the concave surface of the doublet lens faces the object side; therefore, the focal length of the second lens in the XZ direction and the YZ direction is the same, and the focal length of the third lens in the XZ direction and the YZ direction is the same.

[0040] The effective focal length ratio of the eyepiece lens in the XZ direction and the YZ direction satisfies: 0.5 ≤ fx / fy ≤ 1. Such a design can reduce the size of the image source, thereby reducing the size of the eyepiece lens in the width direction by at least 8%.

[0041] The effective focal length of the eyepiece lens in the YZ direction and the effective focal length of the second lens satisfy: -0.7 ≤ f2 / fy ≤-0.4, where f2 is the effective focal length of the second lens. The effective focal length of the eyepiece lens in the YZ direction and the effective focal length of the third lens satisfy: 0.7 ≤ f3 / fy ≤1, where f3 is the effective focal length of the third lens.

[0042] In addition, the effective focal length f1x of the first lens along the XZ direction and the effective focal length f1y of the first lens along the YZ direction satisfy: 0.1≤ f1x / f1y ≤ 0.6;

[0043] An effective focal length f4x of the fourth lens along the XZ direction and an effective focal length f4y of the fourth lens along the YZ direction satisfy: 0.7≤ f4x / f4y≤1.3.

[0044] like Fig.15As shown, a near-eye display module includes an image source 00, an eyepiece lens 01 and a waveguide 02. The image source 00 is used to emit a light signal, and the light signal includes image information. The eyepiece lens 01 is arranged in the light emitting direction of the image source 00, and is used to modulate the light signal. The waveguide 02 is arranged on the side of the eyepiece lens 01 away from the image source 00, and is used to transmit the modulated light signal. The first group of lenses in the eyepiece lens 01 is closer to the image source 00 than the third group of lenses. The image displayed by the image source 00 is transmitted to the waveguide 02 through the eyepiece lens 01, and finally observed by the human eye. The eyepiece lens is the eyepiece lens described above. The image source includes any one of a silicon-based liquid crystal display, an organic light emitting diode, and a micro light emitting diode. The waveguide is at least one of a geometric optical waveguide or a diffraction optical waveguide.

[0045] like Fig.13 and Fig.14 As shown, the pixel shape of the image source can be a square or a rectangle. The pixel shape of the image source is generally a square, and the display screen is generally 16:9 or 4:3, that is, the length is greater than the width, which will cause the size of the eyepiece lens to be large, especially the size in the direction corresponding to the long side of the screen is large, causing the near-eye display module to interfere with the face, reducing wearing comfort. The present invention provides an eyepiece lens for near-eye display, which has different effective focal length values ​​in the XZ direction and the YZ direction, that is, it has different magnifications for the long side and the short side of the image source display screen, so that the pixel shape of the image source can be made into a rectangle, while maintaining the same high resolution, the overall size of the image source is made smaller, thereby reducing the size of the eyepiece lens in the width direction, which can be reduced by at least 8%. Embodiment 1

[0046] In this embodiment, a 0.2-inch silicon-based OLED with a resolution of 640×480 (screen ratio 4:3) and a display area of ​​4.064mm×3.048mm is taken as an example. It is assumed that the horizontal pixel size of the OLED is reduced to 2 / 3 of the original, that is, the aspect ratio a / b of the pixel size is 2 / 3, the vertical display size of the screen remains unchanged, and the horizontal display size becomes smaller, that is, the display area becomes 2.71mm×3.048mm. At this time, the screen ratio is 8:9, and the resolution of 640×480 remains unchanged.

[0047] According to fx / fy=a / b, fx / fy=2 / 3. In the first embodiment, the FOV of the eyepiece lens is 25°, and the effective focal length fy in the YZ direction can be calculated to be 11.4 mm from the silicon-based OLED display area, and the effective focal length fx in the XZ direction can be calculated to be 7.6 mm.

[0048] In the first embodiment, the eyepiece lens adopts a total of four lenses, wherein the first lens and the fourth lens have non-rotationally symmetrical surface shapes, and have different surface shapes and different optical powers in the XZ direction and the YZ direction; the surface shapes of the first lens and the fourth lens include: biconical surface, polynomial, extended polynomial, Zernike standard sag, etc. In this embodiment, a polynomial is adopted, and the sag of the polynomial surface shape is defined as follows:

[0049] ,

[0050] in, It's Yadaka. are coefficients, x and y are the lengths of the lens in the XZ and YZ directions.

[0051] Figure 1 and Figure 2 This is a schematic diagram of the structure of an eyepiece lens for near-eye display provided in the first embodiment of the present invention. It can be seen that the first lens and the fourth lens have different bending directions in the XZ and YZ directions, so that the long side and the short side of the silicon-based OLED can have different zoom ratios. The 8:9 picture displayed by the OLED with a display area of ​​2.71mm×3.048mm is converted into a 4:3 projection picture through the eyepiece lens for human eyes to watch. The display effect of the eyepiece lens is as follows: Figure 3 and Figure 4 As shown, it can be clearly seen that a pair of 8:9 pictures are changed into 4:3 pictures through the eyepiece lens. The size of the eyepiece lens conventionally designed according to the parameter index of this embodiment is 20.1mm×7.2mm×21.3mm, and the size of the eyepiece lens designed in this embodiment is 20.2mm×6.6mm×21.2mm, and the width direction size is reduced by 8%. Figure 5 and Figure 6 shown. Embodiment 2

[0052] In this embodiment, a 0.3-inch silicon-based OLED with a resolution of 1280×720 (screen ratio 16:9) and a display area of ​​6.641mm×3.735mm is taken as an example. It is assumed that the horizontal pixel size of the OLED is reduced to 1 / 2 of the original, that is, the aspect ratio a / b of the pixel size is 1 / 2, the vertical display size of the screen remains unchanged, and the horizontal display size becomes smaller, that is, the display area becomes 3.32mm×3.735mm. At this time, the screen ratio is 8:9, and the resolution of 1280×720 remains unchanged.

[0053] According to fx / fy=a / b, fx / fy=1 / 2. In the second embodiment, the FOV of the eyepiece lens is 30°, and the effective focal length fy in the YZ direction can be calculated to be 14.2 mm from the silicon-based OLED display area, and the effective focal length fx in the XZ direction can be calculated to be 7.1 mm.

[0054] In the embodiment, the eyepiece lens adopts a total of four lenses, wherein the first lens and the fourth lens have non-rotationally symmetric surface shapes, and have different surface shapes and different optical focal powers in the XZ direction and the YZ direction; the surface shapes of the first lens and the fourth lens include: biconical surface, polynomial, extended polynomial, Zernike standard sag, etc., and polynomial is adopted in this embodiment.

[0055] Figure 7 and Figure 8 This is a schematic diagram of the structure of an eyepiece lens for near-eye display provided in Example 1 of the present invention. It can be seen that the first lens and the fourth lens have different bending directions in the XZ and YZ directions, so that the long and short sides of the silicon-based OLED can have different zoom ratios. The 8:9 picture displayed by the OLED with a display area of ​​3.32mm×3.735mm is changed into a 16:9 projection picture entering the human eye for viewing by the human eye, thus meeting the wearer's comfort requirements. Compared with the 16:9 silicon-based OLED with a display area of ​​6.641mm×3.735mm, this lens greatly reduces the required size of the long side of the silicon-based OLED, changing the long side from 6.641mm to 3.32mm, while ensuring the same projection effect. The display effect of the eyepiece lens is as follows: Fig. 9 and Fig.10 As shown, it can be clearly seen that a pair of 8:9 pictures are changed into 16:9 pictures through the eyepiece lens. The size of the eyepiece lens conventionally designed according to the parameter index of this embodiment is 20.1mm×9.8mm×20.9mm, and the size of the eyepiece lens designed in this embodiment is 20.1mm×7.8mm×20.7mm, and the width direction size is reduced by 20%. Fig.11 and Fig.12 shown.

[0056] The "first" and "second" in the names such as "first" and "second" (if any) mentioned in the embodiments of the present application are only used as name identifiers and do not represent the first or second in order.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A near-eye display module, characterized in that: The invention comprises an image source, an eyepiece lens and a waveguide, wherein the image source is used to emit a light signal, wherein the light signal includes image information; the eyepiece lens is arranged in the light emitting direction of the image source, and is used to modulate the light signal; the waveguide is arranged on the side of the eyepiece lens away from the image source, and is used to transmit the modulated light signal; the waveguide is a geometric light waveguide or a diffraction light waveguide; the eyepiece lens comprises a plurality of lens groups coaxially arranged in sequence from the object side to the image side, and the image source is arranged on the object side, and is used to provide a light signal for the eyepiece lens; the X direction is defined as the direction corresponding to the long side of the image source pixel size, the Y direction is defined as the direction corresponding to the short side of the image source pixel size, and the Z direction is defined as the direction corresponding to the length of the eyepiece lens, and the three directions XYZ are perpendicular to each other; the effective focal length ratio of the eyepiece lens in the XZ direction and the YZ direction is determined according to the aspect ratio of the pixel size of the image source, fx / fy=a / b; a is the pixel size length of the image source, and b is the pixel size width; and the effective focal length ratio of the eyepiece lens in the XZ direction and the YZ direction satisfies: 0.5 ≤ fx / fy <1, where fx is the effective focal length of the eyepiece lens in the XZ direction, and fy is the effective focal length of the eyepiece lens in the YZ direction.

2. A near-eye display module according to claim 1, characterized in that: The eyepiece lens comprises a first lens group, a second lens group and a third lens group which are coaxially arranged in sequence from the object side to the image side; the first lens group and the third lens group have non-rotationally symmetric surface shapes, and the second lens group has a rotationally symmetric surface shape.

3. A near-eye display module according to claim 2, characterized in that: The second lens group includes a second lens and a third lens, and the second lens and the third lens form a doublet lens.

4. The near-eye display module according to claim 3, characterized in that: The effective focal length of the eyepiece lens in the YZ direction and the effective focal length of the second lens satisfy: -0.7 ≤ f2 / fy ≤-0.4, where f2 is the effective focal length of the second lens.

5. The near-eye display module according to claim 3, characterized in that: The effective focal length of the eyepiece lens in the YZ direction and the effective focal length of the third lens satisfy: 0.7 ≤ f3 / fy ≤1, where f3 is the effective focal length of the third lens.

6. The near-eye display module according to claim 2, characterized in that: The first group of lenses includes a first lens, and an effective focal length f1x of the first lens along an XZ direction and an effective focal length f1y of the first lens along a YZ direction satisfy: 0.1≤ f1x / f1y≤0.

6.

7. The near-eye display module according to claim 2, characterized in that: The third lens group includes a fourth lens, and an effective focal length f4x of the fourth lens along the XZ direction and an effective focal length f4y of the fourth lens along the YZ direction satisfy: 0.7≤f4x / f4y≤1.

3.

8. The near-eye display module according to claim 1, characterized in that: The image source is a liquid crystal on silicon display, an organic light emitting diode or a micro light emitting diode.

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