Eyepiece lens and near-to-eye display device

Abstract

The utility model discloses an eyepiece lens and a near-to-eye display device. The eyepiece lens comprises a first lens, a second lens, a third lens and a fourth lens which are coaxially and sequentially arranged from an object side to an image side, the first lens, the second lens, the third lens and the fourth lens are convex-concave lenses, the object side surfaces of the lenses are concave surfaces, and the image side surfaces of the lenses are convex surfaces; the first lens and the fourth lens use aspheric surfaces, so that the image quality of the lens can be effectively improved, and the total volume size of the lens can be compressed; the second lens and the third lens form a double-bonding lens group, provide negative focal power and gather light; according to the utility model, fewer lenses are used to form the eyepiece lens, a high-quality imaging effect is realized under a small size, and the watching experience of a user is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of optics, and in particular to an eyepiece lens and a near-eye display device. 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 the waveguide method 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. Utility Model Content

[0004] Technical purpose: In view of the shortcomings of the existing technology, the utility model discloses an eyepiece lens and a near-eye display device, which can solve the problems of the large number of lenses, large size and poor imaging quality in the existing optical system.

[0005] Technical solution: To achieve the above technical objectives, the utility model adopts the following technical solution:

[0006] An eyepiece lens, comprising a first lens, a second lens, a third lens and a fourth lens coaxially arranged in sequence from an object side to an image side;

[0007] The first lens is a convex-concave lens, whose object side surface is concave and image side surface is convex, and is used to provide positive optical power;

[0008] The second lens is a convex-concave lens, the object side surface of which is concave and the image side surface is convex, and is used to provide negative optical power;

[0009] The third lens is a convex-concave lens, whose object side surface is concave and image side surface is convex, and is used to provide positive optical power;

[0010] The fourth lens is a convex-concave lens, whose object side surface is concave and image side surface is convex, and is used to provide positive focal power;

[0011] The surfaces of the first lens, the second lens, the third lens, and the fourth lens are spherical or aspherical, and the second lens and the third lens form a doublet lens.

[0012] Preferably, the field of view angle of the eyepiece lens is FOV, where FOV = 30°; the effective focal power of the eyepiece lens is f, where 12 mm < f < 16 mm.

[0013] Preferably, the focal power of the first lens is f1, where 8 mm < f1 < 16 mm; the focal power of the second lens is f2, where -10 mm < f2 < -5 mm; the focal power of the third lens is f3, where 8 mm < f3 < 16 mm; the focal power of the fourth lens is f4, where 20 mm < f4 < 40 mm.

[0014] Preferably, the object side and the image side of the first lens and the fourth lens are both even aspheres.

[0015] Preferably, the materials of the first lens, the second lens, the third lens, and the fourth lens are glass.

[0016] The present invention also provides a near-eye display device, including a display chip image source, a transmission medium, and an eyepiece lens as described above. The display chip image source is disposed in the object side direction of the eyepiece lens and is coaxial with the eyepiece lens, and the transmission medium is disposed in the image side direction of the eyepiece lens and is coaxial with the eyepiece lens.

[0017] Preferably, the display chip image source includes any one of a liquid crystal on silicon display, an organic light-emitting diode, and a micro light-emitting diode.

[0018] Preferably, the size of the display chip image source is 0.2 inches - 0.4 inches.

[0019] Preferably, the transmission medium is a geometric optical waveguide or a diffractive optical waveguide.

[0020] Beneficial effects: The present utility model provides an eyepiece lens for near-eye display, which uses a total of four lenses. The first lens and the fourth lens use aspheres, which can effectively improve the imaging quality of the lens and compress the overall volume size of the lens. The second and third lenses are doublet lenses, which gather light and allow large-angle light to enter the optical surface. In addition, the glued lens reduces the assembly steps of one of the lenses and reduces the assembly difficulty of the eyepiece lens. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0022] Figure 1A schematic diagram of an eyepiece lens provided by an embodiment of the present invention;

[0023] Figure 2 A schematic diagram of an MTF curve of an eyepiece lens transfer function provided by an embodiment of the present invention;

[0024] Figure 3 A spot diagram of the eyepiece lens in the full field of view provided by an embodiment of the present invention;

[0025] Figure 4 A schematic diagram of field curvature and distortion of an eyepiece lens provided in an embodiment of the present invention;

[0026] Figure 5 A schematic diagram of axial chromatic aberration of an eyepiece lens provided in an embodiment of the present invention;

[0027] Figure 6 A schematic diagram of the structure of a near-eye display device provided in an embodiment of the present invention.

[0028] In the figure: 100, eyepiece lens; 10, first lens; 11, concave surface; 12, convex surface; 20, second lens; 21, concave surface; 22, convex surface; 30, third lens; 31, concave surface; 32, convex surface; 40, fourth lens; 41, concave surface; 42, convex surface; 200, display chip image source; 300, transmission medium. DETAILED DESCRIPTION

[0029] The present invention will be described more clearly and completely below by way of a preferred embodiment in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the embodiment.

[0030] like Figure 1 As shown, an eyepiece lens 100 includes a first lens 10, a second lens 20, a third lens 30 and a fourth lens 40 which are coaxially arranged in sequence from the object side to the image side; wherein the first lens 10 is a convex-concave lens, whose object side surface 11 is a concave surface, and whose image side surface 12 is a convex surface, and is used to provide positive focal power; the second lens 20 is a convex-concave lens, whose object side surface 21 is a concave surface, and whose image side surface 22 is a convex surface, and is used to provide negative focal power; the third lens 30 is a convex-concave lens, whose object side surface 31 is a concave surface, and whose image side surface 32 is a convex surface, and is used to provide positive focal power; the fourth lens 40 is a convex-concave lens, whose object side surface 41 is a concave surface, and whose image side surface 42 is a convex surface, and is used to provide positive focal power; the surfaces of the first lens 10, the second lens 20, the third lens 30 and the fourth lens 40 are spherical or aspherical, and the second lens 20 and the third lens 30 form a doublet lens.

[0031] In a specific embodiment of the present utility model, both the object side and the image side of the first lens 10 are even aspherical surfaces, which are close to the display chip image source 200, mainly eliminating the off-axis aberration and distortion of the eyepiece lens, improving the imaging quality of the eyepiece lens, and controlling the distortion < 2%.

[0032] The second lens 20 and the third lens 30 form a doublet lens, providing a negative optical power to converge light, and the surfaces of the second lens 20 and the third lens 30 are both spherical surfaces. Among them, the object side 21 of the second lens 20 is a concave surface with a relatively small radius value, which can not only converge light but also correct the distortion, chromatic aberration, and field curvature of the eyepiece lens, reducing the total aberration of the eyepiece lens. Since the second lens 20 and the third lens 30 are cemented lenses, one lens assembly step is reduced, the assembly difficulty of the eyepiece lens is lowered, and the assembly yield is improved.

[0033] Both the object side 41 and the image side 42 of the fourth lens 40 use even aspherical surfaces, mainly eliminating the spherical aberration of the eyepiece lens, controlling the spherical aberration within a small range, and improving the imaging quality of the eyepiece lens.

[0034] The field of view angle of the eyepiece lens is FOV, where FOV = 30°; the effective focal power of the eyepiece lens is f, where 12 mm < f < 16 mm.

[0035] The materials of the first lens 10, the second lens 20, the third lens 30, and the fourth lens 40 are glass. The focal power of the first lens 10 is f1, where 8 mm < f1 < 16 mm; the focal power of the second lens 20 is f2, where -10 mm < f2 < -5 mm; the focal power of the third lens 30 is f3, where 8 mm < f3 < 16 mm; the focal power of the fourth lens 40 is f4, where 20 mm < f4 < 40 mm.

[0036] As Figure 2 shown is a schematic diagram of the modulation transfer function (MTF) curve of the eyepiece lens provided by the embodiment of the present invention at a resolution of 100 lp / mm; MTF refers to a function that takes the spatial frequency as a variable and characterizes the relative changes in the modulation degree and lateral phase shift during the imaging process. The higher the MTF value, the better the imaging quality. As can be Figure 2 seen, the MTF is greater than 0.5 at 30 lp / mm, indicating that the image quality of the eyepiece lens is good.

[0037] As Figure 3 shown is the spot diagram of the eyepiece lens provided by the embodiment of the present invention in the full field of view. The smaller the radius of the spot diagram, the more concentrated the converging light, the smaller the aberration, that is, the better the image quality. As can be Figure 3It can be seen that the RMS radius of the central field of view spot is less than 2μm, and the RMS radius of all field of view spots is less than 6μm, indicating that the imaging quality of the eyepiece lens is good.

[0038] like Figure 4 The figure shows a schematic diagram of the field curvature and distortion of the eyepiece lens provided in an embodiment of the present invention. The field curvature is between -0.05 mm and 0.05 mm, and the distortion is <1%. The small distortion can improve the comfort of the human eye in viewing virtual images.

[0039] like Figure 5 The figure is a schematic diagram of the axial chromatic aberration of the eyepiece lens provided by an embodiment of the present invention. The axial chromatic aberration is between -0.05 mm and 0.05 mm. The small chromatic aberration can restore the color more realistically.

[0040] like Figure 6 As shown, the present invention also provides a near-eye display device, including a display chip image source 200 and a transmission medium 300, and an eyepiece lens 100 as described above, wherein the display chip image source 200 is arranged in the direction of the object side of the eyepiece lens 100 and is coaxial with the eyepiece lens 100, and the transmission medium 300 is arranged in the direction of the image side of the eyepiece lens 100 and is coaxial with the eyepiece lens 100.

[0041] In a specific embodiment of the present invention, the display chip image source 200 includes any one of a silicon-based liquid crystal display, an organic light-emitting diode, and a micro light-emitting diode, and the size of the display chip image source 200 is 0.2 inches-0.4 inches. The eyepiece lens is relatively small in size, and the use of a small-sized image source is more conducive to reducing the volume of the near-eye display device.

[0042] The transmission medium 300 is a geometric optical waveguide or a diffraction optical waveguide. The optical waveguide transmits the parallel light emitted by the eyepiece lens based on the principle of total reflection to the retina of the human eye for viewing.

[0043] 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 protection scope of the present invention.

Claims

1. An eyepiece lens, characterized in that: It includes a first lens, a second lens, a third lens, and a fourth lens coaxially arranged in sequence from the object side to the image side; The first lens is a convex-concave lens, with its object side being concave and its image side being convex, and is used to provide a positive optical power; The second lens is a convex-concave lens, with its object side being concave and its image side being convex, and is used to provide a negative optical power; The third lens is a convex-concave lens, with its object side being concave and its image side being convex, and is used to provide a positive optical power; The fourth lens is a convex-concave lens, with its object side being concave and its image side being convex, and is used to provide a positive optical power; The surfaces of the first lens, the second lens, the third lens, and the fourth lens are spherical or aspherical, and the second lens and the third lens form a doublet lens.

2. An eyepiece lens according to claim 1, characterized in that: The field of view angle of the eyepiece lens is FOV, where FOV = 30°; the effective focal power of the eyepiece lens is f, where 12 mm < f < 16 mm.

3. An eyepiece lens according to claim 1, characterized in that: The focal power of the first lens is f1, where 8 mm < f1 < 16 mm; the focal power of the second lens is f2, where -10 mm < f2 < -5 mm; the focal power of the third lens is f3, where 8 mm < f3 < 16 mm; the focal power of the fourth lens is f4, where 20 mm < f4 < 40 mm.

4. The eyepiece lens according to claim 1, characterized in that: The object side and the image side of the first lens and the fourth lens are both even aspherical surfaces.

5. The eyepiece lens according to claim 1, characterized in that: The materials of the first lens, the second lens, the third lens, and the fourth lens are glass.

6. A near-eye display device, characterized in that: It includes a display chip image source and a transmission medium, and an eyepiece lens according to any one of claims 1-5. The display chip image source is arranged on the object side direction of the eyepiece lens and is coaxial with the eyepiece lens, and the transmission medium is arranged on the image side direction of the eyepiece lens and is coaxial with the eyepiece lens.

7. The near-eye display device according to claim 6, characterized in that: The display chip image source includes any one of a liquid crystal on silicon display, an organic light emitting diode, and a micro light emitting diode.

8. The near-eye display device according to claim 7, characterized in that: The size of the display chip image source is 0.2 inches - 0.4 inches.

9. The near-eye display device according to claim 6, characterized in that: The transmission medium is a geometric optical waveguide or a diffractive optical waveguide.

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