WO2022141389A1 - Large-field-angle eyepiece optical system and head-mounted display device - Google Patents

Abstract

A large-field-angle eyepiece optical system and a head-mounted display device. The eyepiece optical system comprises a first lens group (D1), a second lens group (D2) and a third lens group (D3) sequentially arranged coaxially in an optical axis direction from an eye observation side to a micro image display (IMG) side, wherein the effective focal lengths of the first lens group (D1), the second lens group (D2) and the third lens group (D3) are in a combination of positive, negative and positive; the first lens group (D1) comprises a first lens (L1) close to an eye side and a second lens (L2) away from the eye side; the first lens group (D1) comprises at least two Fresnel optical surfaces; the first lens (L1) comprises at least one Fresnel optical surface; the second lens group (D2) comprises a third lens (L3) adjacent to the first lens group (D1); the third lens (L3) is a negative lens; the third lens group (D3) comprises a fourth lens (L4) and a fifth lens (L5) which are adjacent to the second lens group (D2) and sequentially arranged along an optical axis; and both the fourth lens (L4) and the fifth lens (L5) are positive lenses. The eyepiece lens optical system can simultaneously achieve the effects of large field angle, high image quality, low distortion, small curvature of field and small volume.

Description

An eyepiece optical system with a large field of view and a head-mounted display device technical field

The present invention relates to the field of optical technology, and more particularly, to an eyepiece optical system with a large viewing angle and a head-mounted display device.

Background technique

With the continuous development of electronic devices towards ultra-miniaturization, as well as the development of new computer, microelectronics, optoelectronic devices and communication theories and technologies, wearable computing, a new model based on "people-oriented" and "human-machine integration" has become possible. . Applications continue to emerge in military, industrial, medical, education, consumer and other fields. In a typical wearable computing system architecture, the head-mounted display device is a key component. The head-mounted display device guides the video image light emitted by the miniature image display (such as transmissive or reflective liquid crystal display, organic electroluminescent device, DMD device) to the user's pupil through optical technology, and the user's near vision The scope realizes virtual and enlarged images, and provides users with intuitive and visible images, videos, and text information. The eyepiece optical system is the core of the head-mounted display device, which realizes the function of displaying a miniature image in front of the human eyes to form a virtual magnified image.

The head-mounted display device is developing towards the direction of compact size, light weight, easy to wear on the head and lightening of the load. At the same time, large field of view and visual comfort have gradually become the key factors to measure the quality of head-mounted display devices. Large field of view determines the effect of high-presence visual experience, and high image quality and low distortion determine the comfort of visual experience. Spend. To meet these requirements, it is necessary for the eyepiece optical system to achieve a large field of view, high image resolution, low distortion, small field curvature, and small volume as much as possible. At the same time, satisfying the above optical performance is very important for system design and aberration optimization. challenge.

Fresnel structures adopted in Patent Document 1 (Chinese Patent Publication No. CN109416469A), Patent Document 2 (Chinese Patent Publication No. CN105759424B), Patent Document 3 (Chinese Patent Publication No. CN107015361B), and Patent Document 4 (Chinese Patent Publication No. CN111381371A) Although good focusing effects can be achieved in the optical system, Patent Document 1 and Patent Document 3 completely rely on Fresnel lenses, while Patent Documents 2 and 4 are Fresnel lenses and single and double positive lenses. Combined, it is inevitable that it is difficult to make achievements in the aberration of the optical system, and there is a large distortion and spherical aberration.

Patent Document 5 (Chinese Patent Publication No. CN105278109A) provides an optical system using a combination of positive, negative, and positive lens groups, and provides an optical system that uses a combination of positive, negative, and positive lens groups. It is a traditional spherical and even-order aspheric optical system. Although it has great advantages in aberration correction, it is extremely cumbersome under the same optical system parameters.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an eyepiece optical system and a head-mounted display device with a large field of view in view of the above-mentioned defects of the prior art, which can achieve a large field of view, high image resolution, low distortion, and a small field of view. Curve, small volume and other indicators.

The technical solution adopted by the present invention to solve the technical problem is: constructing an eyepiece optical system with a large field of view, comprising a first lens group, a first lens group, The second lens group and the third lens group, and the effective focal lengths of the first lens group, the second lens group and the third lens group are positive, negative and positive combinations; the first lens group is composed of two The first lens group includes at least two Fresnel optical surfaces; the first lens includes at least one Describe the Fresnel optical surface;

The effective focal length of the optical system is set to F, and the effective focal length of the first lens group is set to f ₁ , then F and f ₁ satisfy the following relational formula (1):

0.50≤f ₁ /F≤1.33 (1);

The second lens group is composed of an optical lens; wherein the second lens group includes a third lens adjacent to the first lens group; the third lens is a negative lens;

The third lens group is composed of two optical lenses; wherein the third lens group includes a fourth lens and a fifth lens adjacent to the second lens group and arranged in sequence along the optical axis; the fourth lens And the fifth lens is a positive lens;

The material properties of the first lens and the second lens satisfy the following relational expressions (2) and (3):

1.49<Nd ₁₁ <1.65 (2);

1.49<Nd ₁₂ <1.65 (3);

Wherein, Nd ₁₁ and Nd ₁₂ are the refractive indices of the first lens and the second lens at the d-line, respectively.

Further, the effective focal length f ₁₁ of the first lens and the effective focal length f ₁ of the first lens group satisfy the following relational formula (4):

1.50≤f ₁₁ /f ₁ ≤4.48 (4).

Further, the effective focal length of the optical system is F; the effective focal length of the second lens group is set to f ₂ , then F and f ₂ satisfy the following relational formula (5):

-0.98≤f ₂ /F≤-0.35 (5).

Further, if the effective focal length of the first lens group is f ₁ , and the effective focal length of the third lens group is set as f ₃ , then f ₁ and f ₃ satisfy the following relational formula (6):

0.02≦f ₁ /f ₃ ≦2.15 (6).

Further, each of the first lens and the second lens includes one of the Fresnel optical surfaces.

Further, the two Fresnel optical surfaces are arranged adjacently.

Further, the base surfaces of the two Fresnel optical surfaces are plane or aspherical.

Further, the third lens is a biconcave lens; the optical surface of the fourth lens close to the human eye is concave toward the human eye; the optical surface of the fifth lens close to the human eye is convex toward the human eye.

Further, one or more optical surfaces of the first lens and the second lens are even-order aspheric surfaces; and the optical surfaces of the third lens are all even-order aspheric surfaces.

Further, the material of the third lens and the fifth lens is optical glass or optical plastic.

Further, the expression of the aspheric surface of the lens is:

The present invention also provides a head-mounted display device, comprising a miniature image display and an eyepiece; the eyepiece is located between the human eye and the microscopic image display; the eyepiece is the eyepiece optical system described in any one of the foregoing.

Further, the miniature image display is an organic electroluminescence device, a transmissive liquid crystal display or a reflective liquid crystal display.

Further, the head-mounted display device includes two identical and symmetrically arranged eyepiece optical systems.

The beneficial effects of the invention are: a combination of a double Fresnel optical surface type and a traditional optical spherical surface and aspherical surface type is adopted, and the combination of positive, negative and positive lens groups and the focal length of each lens can meet specific matching conditions. While achieving the advantages of large field of view, high image quality, low distortion, small field curvature, small volume and other indicators under the condition of It reduces the sensitivity of each optical component, facilitates the processing and assembly of the components, further improves the field of view, field curvature, distortion and other indicators in the optical system, and greatly improves the user's visual comfort experience. Through the eyepiece optical system of the present invention, the observer can watch a large-scale picture with full-frame high-definition, no distortion and uniform image quality, so as to achieve a high-presence visual experience.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be further described below with reference to the accompanying drawings and embodiments. Ordinary technicians can also obtain other drawings based on these drawings without creative labor:

1 is a schematic structural diagram of an eyepiece optical system according to a first embodiment of the present invention;

FIG. 2 is a schematic diagram of a diffused spot array of the eyepiece optical system according to the first embodiment of the present invention;

Fig. 3 is the distortion schematic diagram of the eyepiece optical system of the first embodiment of the present invention;

4 is a schematic diagram of the optical transfer function MTF of the eyepiece optical system according to the first embodiment of the present invention;

5 is a schematic structural diagram of an eyepiece optical system according to a second embodiment of the present invention;

6 is a schematic diagram of a speckle array of an eyepiece optical system according to a second embodiment of the present invention;

Fig. 7 is the distortion schematic diagram of the eyepiece optical system of the second embodiment of the present invention;

8 is a schematic diagram of the optical transfer function MTF of the eyepiece optical system of the second embodiment of the present invention;

9 is a schematic structural diagram of an eyepiece optical system according to a third embodiment of the present invention;

10 is a schematic diagram of a diffused spot array of an eyepiece optical system according to a third embodiment of the present invention;

11 is a schematic diagram of the distortion of the eyepiece optical system according to the third embodiment of the present invention;

12 is a schematic diagram of the optical transfer function MTF of the eyepiece optical system according to the third embodiment of the present invention.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the following will be described clearly and completely in combination with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, and Not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

The present invention constructs an eyepiece optical system with a large field of view, comprising a first lens group, a second lens group and a third lens group which are coaxially arranged in sequence along the optical axis from the observation side of the human eye to the side of the micro-image display, and The effective focal lengths of the first lens group, the second lens group and the third lens group are a combination of positive, negative and positive; the first lens group is composed of two optical lenses, which are the first lens close to the human eye and the first lens away from the human eye. The second lens on the side; the first lens group includes at least two Fresnel optical surfaces; the first lens includes at least one Fresnel optical surface;

The effective focal length of the optical system is set to F, and the effective focal length of the first lens group is set to f ₁ , then F and f ₁ satisfy the following relational formula (1):

0.50≤f ₁ /F≤1.33 (1);

Wherein, f ₁ /F can be 0.50, 0.53, 0.67, 0.87, 0.99, 1.21, 1.29, 0.33 and so on.

The second lens group is composed of an optical lens; wherein the second lens group includes a third lens adjacent to the first lens group; the third lens is a negative lens;

The third lens group is composed of two optical lenses; the third lens group includes a fourth lens and a fifth lens that are adjacent to the second lens group and arranged in sequence along the optical axis; the fourth lens and the fifth lens are both positive lenses ;

The material properties of the first lens and the second lens satisfy the following relational expressions (2), (3):

1.49<Nd ₁₁ <1.65 (2);

1.49<Nd ₁₂ <1.65 (3);

Wherein, Nd ₁₁ and Nd ₁₂ are the refractive indices of the first lens and the second lens at the d-line, respectively. The wavelength of the d-line is 589.3nm, and the materials of the first lens and the second lens are optional: E48R, K26R, EP3000, OKP1, etc.

Among them, the first lens group, the second lens group and the third lens group adopt the combination of positive, negative and positive, and each lens in the second lens group and the third lens group adopts the combination of negative, positive and positive to fully correct the The aberration of the system is reduced, and the optical resolution of the system is improved. More importantly, the structure of double Fresnel surfaces is adopted in the first lens group, which shares most of the effective focal lengths in the optical system, effectively reduces the difference in the outer diameter of each lens, and reduces the size of the eyepiece optics. The overall size of the system improves the reliability of subsequent mass production. And the second lens group can provide a sufficient negative effective focal length to ensure that the eyepiece optical system can achieve a large enough angle of view. At the same time, optical indicators such as large field of view, low distortion, low chromatic aberration, low field curvature, and low astigmatism are realized. Through the eyepiece optical system, the observer can watch a large picture with full-frame high-definition, no distortion and uniform image quality. Achieving a highly immersive visual experience. This product is intended for use with head mounted displays and similar devices.

As shown in FIG. 1, it includes a first lens group, a second lens group, and a third lens group arranged in sequence along the optical axis direction from the observation side of the human eye to the micro-image display; The surface number is 1, and so on (from left to right: 2, 3, 4, 5, 6...), the light emitted from the micro-image display goes through the third lens group, the second lens group , After the first lens group is refracted, it enters the human eye.

In a further embodiment, the effective focal length f ₁₁ of the first lens and the effective focal length f ₁ of the first lens group satisfy the following relational formula (4):

1.50≤f ₁₁ /f ₁ ≤4.48 (4).

Wherein, f ₁₁ /f ₁ can be 1.50, 1.62, 1.83, 1.95, 2.21, 2.75, 2.98, 3.5, 3.89, 4.31, 4.48 and so on.

In a further embodiment, the effective focal length of the optical system is F; the effective focal length of the second lens group is set to f ₂ , then F and f ₂ satisfy the following relational formula (5):

-0.98≤f ₂ /F≤-0.35 (5).

Wherein, f ₂ /F can be -0.98, -0.95, -0.82, -0.77, -0.57, -0.49, -0.41, -0.38, -0.35 and so on.

In a further embodiment, the effective focal length of the first lens group is f ₁ , and the effective focal length of the third lens group is f ₃ , then f ₁ and f ₃ satisfy the following relational formula (6):

0.02≦f ₁ /f ₃ ≦2.15 (6).

Wherein, f ₁ /f ₃ can be 0.02, 0.32, 0.47, 0.67, 0.89, 1.32, 1.55, 1.89, 2.01, 2.11, 2.15 and so on.

The value ranges of f ₁ /F, f ₁₁ /f ₁ , f ₂ /F and f ₁ /f ₃ are closely related to the correction of system aberrations, the processing difficulty of optical components, and the sensitivity of optical component assembly deviations. The value of f ₁ /F in formula (1) is greater than 0.5, so that the aberration of the system can be fully corrected, so as to achieve high-quality optical effects, and the value of f 1 /F is less than 1.33, which improves the machinability of the optical elements in the system; relation; In formula (4), the value of f ₁₁ /f ₁ is greater than 1.5, so that the aberration of the system can be fully corrected, thereby achieving high-quality optical effects, and the value of f 11 /f 1 is less than 4.48, which improves the processability of the optical elements in the system; The value of f ₁ /f ₃ in the relation (6) is greater than 0.02, so that the aberration of the system can be fully corrected, thereby achieving high-quality optical effects, and the value of f 1 /f 3 is less than 2.15, which improves the machinability of the optical elements in the system . The value of f ₂ /F in the relationship (5) is greater than -0.95, so that the corresponding lens can provide sufficient negative effective focal length, so as to better balance and correct system aberrations and achieve good optical effects, and its value is less than -0.35, which reduces the difficulty of spherical aberration correction and facilitates the realization of large optical apertures.

In a further embodiment, the first lens and the second lens respectively include a Fresnel optical surface.

In a further embodiment, the two Fresnel optical surfaces are arranged adjacently.

In a further embodiment, the base surfaces of the two Fresnel optical surfaces are plane or aspherical.

In the above embodiment, the double Fresnel optical surfaces in the eyepiece optical system are respectively arranged on the first lens and the second lens, and are arranged in an adjacent manner, that is, the optical surface of the first lens away from the human eye is a The optical surface of the second lens close to the human eye is the Fresnel surface. The structure of double Fresnel surfaces is adopted, which shares most of the effective focal length in the optical system, effectively reduces the difference between the outer diameters of each lens, reduces the overall size of the eyepiece optical system, and improves subsequent mass production. reliability.

In a further embodiment, the third lens is a double concave lens; the optical surface of the fourth lens close to the human eye is concave toward the human eye; and the optical surface of the fifth lens close to the human eye is convex toward the human eye.

In a further embodiment, one or more optical surfaces of the first lens and the second lens are even-order aspheric surfaces; the optical surfaces of the third lens are all even-order aspheric surfaces.

The aberrations at all levels of the optical system are further optimized and corrected. The optical performance of the eyepiece optical system is further improved.

In a further embodiment, the expression for the aspheric surface of the lens is:

Among them, z is the sag of the optical surface, c is the curvature at the vertex of the aspheric surface, k is the aspheric coefficient, α2, 4, 6... are the coefficients of each order, and r is the distance coordinate from the point on the surface to the optical axis of the lens system.

In a further embodiment, the material of the third lens and the fifth lens is optical glass or optical plastic. The aberrations of all levels of the eyepiece optical system are fully corrected, and the manufacturing cost of the optical element and the weight of the optical system are also controlled.

The principles, solutions and display results of the above-mentioned eyepiece optical system will be further described below through more specific embodiments.

In the following embodiments, the diaphragm E may be the exit pupil of the eyepiece optical system for imaging, which is a virtual light exit aperture. When the pupil of the human eye is at the diaphragm position, the best imaging effect can be observed.

first embodiment

The eyepiece design data of the first embodiment are shown in Table 1 below:

Table I

1 is a 2D structural diagram of the eyepiece optical system of the first embodiment, including a first lens group D1, a second lens group D2 and a first lens group D1, a second lens group D2 and The third lens group D3, the first lens group D1 includes a first lens L1 and a second lens L2; the optical surfaces 2 and 3 in the first lens L1 and the second lens L2 are two Fresnels arranged adjacent to each other On the other hand, the second lens group D2 is a negative effective focal length lens group composed of a negative effective focal length optical lens, respectively including a third lens L3, and the third lens group D3 is a positive effective focal length lens composed of two positive effective focal length optical lenses. The group includes a fourth lens L4 and a fifth lens L5 respectively. The focal length F of the optical system is 16.49, the effective focal length f1 of the _first lens group D1 is 21.93, the effective focal length f2 of the _second lens group D2 is -16.12, and the effective focal length f3 of the third lens group _D3 is 10.22, wherein The Fresnel lens close to the human eye has an effective focal length _f11 of 32.90, that is, f1/ _F is 1.33, _f11 /f1 is _1.5 , f2/ _F is -0.98, and f1/ _f3 is _2.15 .

Accompanying drawing 2, accompanying drawing 3, accompanying drawing 4 are the scattered spot array diagram, the distortion diagram and the optical transfer function MTF diagram of the optical system, respectively, reflecting the light of each field of view in the present embodiment on the image plane (display device (IMG) ) has high resolution and small optical distortion in the unit pixel of ), the resolution per 10mm per unit period reaches more than 0.8, the aberration of the optical system is well corrected, and uniform and high optical performance can be observed through the eyepiece optical system. display image.

Second Embodiment

The eyepiece design data of the second embodiment are shown in Table 2 below:

Table II

5 is a 2D structural diagram of the eyepiece optical system of the second embodiment, including a first lens group D1 and a second lens group D2 that are coaxially arranged along the optical axis direction from the observation side of the human eye to the display device (IMG) side. and the third lens group D3, the first lens group D1 includes a first lens L1 and a second lens L2; the optical surfaces 2 and 3 in the first lens L1 and the second lens L2 are two Fresnels arranged adjacent to each other. On the ear surface, the second lens group D2 is a negative effective focal length lens group composed of a negative effective focal length optical lens, respectively including a third lens L3, and the third lens group D3 is composed of two positive effective focal length optical lenses. The lens group includes a fourth lens L4 and a fifth lens L5 respectively. Compared with the first embodiment, the main feature of the second embodiment is that each optical index is slightly lower, and the imaging quality is good. The focal length F of the optical system is 22.26, the effective focal length f1 of the _first lens group D1 is 11.13, the effective focal length f2 of the _second lens group D2 is -7.79, and the effective focal length f3 of the third lens group _D3 is 546.84, wherein The Fresnel lens close to the human eye has an effective focal length f ₁₁ of 49.82, that is, f ₁ /F is 0.50, f ₁₁ /f ₁ is 4.48, f ₂ /F is -0.35, and f ₁ /f ₃ is 0.02.

Fig. 6, Fig. 7, Fig. 8 are the scattered spot array diagram, the distortion diagram and the optical transfer function MTF diagram of the optical system, respectively, reflecting the light of each field of view in the present embodiment on the image plane (display device (IMG) ) has high resolution and small optical distortion in the unit pixel of ), the resolution per 10mm per unit period reaches more than 0.8, the aberration of the optical system is well corrected, and uniform and high optical performance can be observed through the eyepiece optical system. display image.

Third Embodiment

The eyepiece design data of the third embodiment are shown in Table 3 below:

Table 3

9 is a 2D structural diagram of the eyepiece optical system of the third embodiment, including a first lens group D1 and a second lens group D2 that are coaxially arranged along the optical axis direction from the observation side of the human eye to the display device (IMG) side. and the third lens group D3, the first lens group D1 includes a first lens L1 and a second lens L2; the optical surfaces 2 and 3 in the first lens L1 and the second lens L2 are two Fresnels arranged adjacent to each other. On the ear surface, the second lens group D2 is a negative effective focal length lens group composed of a negative effective focal length optical lens, respectively including a third lens L3, and the third lens group D3 is composed of two positive effective focal length optical lenses. The lens group includes a fourth lens L4 and a fifth lens L5 respectively. Compared with the first embodiment, the main feature of the third embodiment is that each optical index is higher, and the imaging quality is good. The focal length F of the optical system is 16.58, the effective focal length f1 of the _first lens group D1 is 11.39, the effective focal length f2 of the _second lens group D2 is -14.09, and the effective focal length f3 of the third lens group _D3 is 16.89, wherein The Fresnel lens close to the human eye has an effective focal length _f11 of 23.82, that is, f1/ _F is 0.69, _f11 /f1 is 2.09, _f2 / _F is _-0.85 , and f1/ _f3 is 0.67.

Fig. 10, Fig. 11, Fig. 12 are the diffused spot array diagram, distortion diagram and optical transfer function MTF diagram of the optical system, respectively, which reflect the light of each field of view in this embodiment on the image plane (display device (IMG) ) has high resolution and small optical distortion in the unit pixel of ), the resolution per 10mm per unit period reaches more than 0.7, the aberration of the optical system is well corrected, and uniform and high optical performance can be observed through the eyepiece optical system. display image.

The data of the above-mentioned embodiments one to three all meet the parameter requirements recorded in the summary of the invention, and the results are shown in the following table four:

Table 4

	f 1 /F	f 11 /f 1	f 2 /F	f 1 /f 00
Example 1	1.33	1.5	-0.98	2.15
Embodiment 2	0.50	4.48	-0.35	0.02

Embodiment 3

0.69

2.09

-0.85

0.67

The present invention also provides a head-mounted display device, comprising a miniature image display and an eyepiece; the eyepiece is located between the human eye and the miniature image display; the eyepiece is the eyepiece optical system of any one of the foregoing.

Preferably, the miniature image display is an organic electroluminescent device, a transmissive liquid crystal display or a reflective liquid crystal display.

Preferably, the head mounted display device comprises two identical and symmetrically arranged eyepiece optical systems.

To sum up, the eyepiece optical system of the above-mentioned embodiments of the present invention adopts a combination of a double Fresnel optical surface and a traditional optical spherical and aspherical surface, combined with a combination of positive, negative and positive lens groups and each lens The focal length of the optical system achieves its advantages of large field of view, high image quality, low distortion, small field curvature, small volume and other indicators under the condition of meeting specific matching conditions, and also greatly reduces the weight of the optical system. The system aberration is greatly eliminated, the sensitivity of each optical component is reduced, the processing and assembly of the components are easy, and the field of view, field curvature, distortion and other indicators in the optical system are further improved, and the user's visual comfort experience is greatly improved. Through the eyepiece optical system of the present invention, an observer can watch a large-scale picture with full-frame high definition, no distortion and uniform image quality, thereby achieving a visual experience with a high sense of presence.

It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes should fall within the protection scope of the appended claims of the present invention.

Claims (13)

1. An eyepiece optical system with a large field of view is characterized in that: it comprises a first lens group, a second lens group and a third lens group which are coaxially arranged in order along the optical axis from the observation side of the human eye to the side of the micro-image display, And the effective focal lengths of the first lens group, the second lens group and the third lens group are a combination of positive, negative and positive; the first lens group is composed of two optical lenses, which are respectively close to the human eye. a first lens on the side and a second lens on the side away from the human eye; the first lens group includes at least two Fresnel optical surfaces; the first lens includes at least one of the Fresnel optical surfaces;

   The effective focal length of the optical system is set to F, and the effective focal length of the first lens group is set to f ₁ , then F and f ₁ satisfy the following relational formula (1):

   0.50≤f ₁ /F≤1.33 (1);

   The second lens group is composed of an optical lens; wherein the second lens group includes a third lens adjacent to the first lens group; the third lens is a negative lens;

   The third lens group is composed of two optical lenses; wherein the third lens group includes a fourth lens and a fifth lens adjacent to the second lens group and arranged in sequence along the optical axis; the fourth lens And the fifth lens is a positive lens;

   The material properties of the first lens and the second lens satisfy the following relational expressions (2) and (3):

   1.49<Nd ₁₁ <1.65 (2);

   1.49<Nd ₁₂ <1.65 (3);

   Wherein, Nd ₁₁ and Nd ₁₂ are the refractive indices of the first lens and the second lens at the d-line, respectively.
2. The eyepiece optical system with a large field of view according to claim 1, wherein the effective focal length f ₁₁ of the first lens and the effective focal length f ₁ of the first lens group satisfy the following relational formula (4):

   1.50≤f ₁₁ /f ₁ ≤4.48 (4).
3. The eyepiece optical system with a large field of view according to claim 1, wherein the effective focal length of the optical system is F; the effective focal length of the second lens group is set to f ₂ , then F and f ₂ satisfy The following relational formula (5):

   -0.98≤f ₂ /F≤-0.35 (5).
4. The eyepiece optical system with a large field of view according to claim 1, wherein the effective focal length of the first lens group is f ₁ , and the effective focal length of the third lens group is f ₃ , then f ₁ , f ₃ satisfies the following relational formula (6):

   0.02≦f ₁ /f ₃ ≦2.15 (6).
5. The eyepiece optical system with a large field of view according to claim 1, wherein the first lens and the second lens respectively include one of the Fresnel optical surfaces.
6. The eyepiece optical system with a large field of view according to claim 5, wherein the two Fresnel optical surfaces are arranged adjacently.
7. The eyepiece optical system with a large field of view according to claim 5, wherein the base surfaces of the two Fresnel optical surfaces are plane or aspherical.
8. The eyepiece optical system with a large field of view according to claim 1, wherein the third lens is a biconcave lens; the optical surface of the fourth lens close to the human eye is concave toward the human eye; The optical surface of the five-lens lens close to the human eye is convex toward the human eye.
9. The eyepiece optical system with a large field of view according to claim 1, wherein one or more optical surfaces of the first lens and the second lens are even-order aspheric surfaces; the third lens The optical surfaces are all even-order aspherical surfaces.
10. The eyepiece optical system with a large field of view according to claim 1, wherein the third lens and the fifth lens are made of optical glass or optical plastic.
11. A head-mounted display device, comprising a miniature image display and an eyepiece; the eyepiece is located between a human eye and the miniature image display; wherein the eyepiece is the eyepiece according to any one of claims 1-10 optical system.
12. The head-mounted display device according to claim 11, wherein the micro-image display is an organic electroluminescence device, a transmissive liquid crystal display or a reflective liquid crystal display.
13. The head-mounted display device according to claim 11 or 12, wherein the head-mounted display device comprises two identical and symmetrically arranged eyepiece optical systems.

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