CN104898283A - Ocular lens system and head-mounted display - Google Patents

Abstract

The invention discloses an eyepiece system and a head-mounted display. The eyepiece system includes: a display screen, a concave reflector and a positive lens group; the concave reflector is used to reflect light emitted by the display screen into the positive lens group; the positive lens group , used to refract the light reflected by the concave mirror into the human eye. The eyepiece system provided by the present invention uses a concave reflector to cooperate with the lens group, which reduces the volume of the eyepiece system. In the process of converging light, the concave reflector bears a part of the optical power of the eyepiece system, reducing the power of the eyepiece system. The requirement for the focal power of the lens group not only reduces the chromatic aberration produced by the lens group, but also reduces the processing materials of the lens group correspondingly; and because the concave mirror does not produce chromatic aberration in the process of converging light, it can greatly reduce The chromatic aberration of the eyepiece system is eliminated, the imaging quality is improved, and the quality and volume of the eyepiece system are reduced. The eyepiece system is applied to a head-mounted display to give users a more perfect visual experience.

Description

An eyepiece system and a head-mounted display

technical field

The invention relates to the technical field of visual equipment, in particular to an eyepiece system and a head-mounted display.

Background technique

At present, with the continuous development of technology, head-mounted displays have entered the civilian market, and more and more people have begun to use such products to enjoy an immersive visual experience through the eyepiece system in the head-mounted display. However, in the design scheme of the eyepiece system of the head-mounted display currently on the market, the lens group is generally required to bear the optical power of the entire eyepiece system, so multiple lenses are required to adapt to each other, and the chromatic aberration produced by the multiple lenses makes the imaging of the eyepiece system The quality is greatly reduced, and the overall eyepiece system has the disadvantages of large volume and high quality. The bulky head-mounted display puts a lot of pressure on the user's head, which greatly reduces the user's experience and comfort.

Contents of the invention

In view of the above problems, the present invention provides an eyepiece system and a head-mounted display to solve the above problems or at least partly solve the above problems.

According to one aspect of the present invention, an eyepiece system is provided, the eyepiece system includes: a display screen, a concave mirror and a positive lens group;

The concave reflector is used to reflect the light emitted by the display screen into the positive lens group;

The positive lens group is used for refracting the light reflected by the concave mirror into human eyes.

Optionally, the positive lens group is a Fresnel lens.

Optionally, the reflective surface of the concave reflector is a concave spherical surface;

The base of the Fresnel lens is a plane, its light incident surface is a convex aspheric surface, and its light exit surface is an annular Fresnel surface with positive refractive power.

Optionally, the aspheric quadratic coefficients of the convex aspheric surface of the Fresnel lens are: K2 and K4, which satisfy the following relationship:

K2<-1, K4<-50.

Optionally, the focal length of the eyepiece system is f, the focal length of the concave mirror is f1, and the focal length of the Fresnel lens is f2, satisfying the following relationship:

3<f1/f<10;

0.3<f2/f<1.2.

Optionally, the distance between the concave reflector and the display screen on the optical axis is L, 20<L<40.

Optionally, the inclination angle of the concave reflector on the optical axis of the Fresnel lens is λ, 30°<λ<60°.

Optionally, the Fresnel lens is made of plastic, and the ranges of its refractive index and Abbe number are: 1.45<n<1.70, 50<v<75.

According to another aspect of the present invention, a head-mounted display is provided, and the head-mounted display includes the eyepiece system described in any one of the above items.

Optionally, the head-mounted display adjusts the focal length of the eyepiece system within a certain range; the eyepiece system realizes the focus adjustment according to the user's operation of moving the lens group in the eyepiece system.

It can be seen from the above that the eyepiece system provided by the present invention uses a concave reflector to cooperate with the lens group in the process of light transmission, which reduces the volume of the eyepiece system, so that the light generated by the display screen converges and enters the human eye. An upright, magnified virtual image is formed. Among them, in the process of converging light rays, the concave reflector bears part of the optical power of the eyepiece system, which reduces the optical power requirements of the eyepiece system for the lens group, not only reduces the chromatic aberration produced by the lens group, but also reduces It reduces the processing materials for the lens group; and because the concave mirror does not produce chromatic aberration in the process of converging light, it can greatly reduce the chromatic aberration of the eyepiece system, improve the imaging quality, and reduce the quality and volume of the eyepiece system. The eyepiece system is applied to a head-mounted display to give users a more perfect visual experience.

Description of drawings

Fig. 1 shows a schematic diagram of an eyepiece system according to an embodiment of the present invention;

Figure 2A shows a schematic diagram of a Fresnel lens according to one embodiment of the present invention;

Fig. 2B shows a schematic diagram of a common lens equivalent to a Fresnel lens according to an embodiment of the present invention;

Figure 3 shows a spot diagram of an eyepiece system according to one embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the implementation manner of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Fig. 1 shows a schematic diagram of an eyepiece system according to an embodiment of the present invention. As shown in FIG. 1 , the eyepiece system includes: a display screen 110 , a concave mirror 120 , a positive lens group 130 and a diaphragm 140 . The concave reflector 120 reflects the light emitted by the display screen 110 into the positive lens group 130; the positive lens group 130 refracts the light reflected by the concave reflector 120 into the aperture 140; The eyepiece system shown in FIG. 1 finally injects the light emitted by the display screen 110 into the human eyes, and forms an enlarged virtual image in the distance before the human eyes, which is what the human eyes see.

It can be seen that the eyepiece system shown in Figure 1 uses a concave reflector to cooperate with the lens group in the light transmission process, which reduces the volume of the eyepiece system, so that the light generated by the display screen converges and enters the human eye. An upright, magnified virtual image is formed. Among them, in the process of converging light rays, the concave reflector bears a part of the optical power of the eyepiece system, which reduces the optical power requirements of the eyepiece system for the lens group, not only reduces the chromatic aberration produced by the lens group, but also correspondingly Reduce the processing materials of the lens group; and because the concave mirror will not produce chromatic aberration in the process of converging light, it can greatly reduce the chromatic aberration of the eyepiece system, improve the imaging quality, reduce the quality and volume of the eyepiece system, and give users more For a perfect visual experience.

In one embodiment of the present invention, the reflective surface of the concave mirror 120 in the eyepiece system shown in FIG. 1 is a concave spherical surface; the positive lens group 130 is a Fresnel lens. In this embodiment, the overall focal length of the eyepiece system shown in FIG. 1 is f, the focal length of the concave mirror 120 is f1, and the focal length of the Fresnel lens 130 is f2, satisfying the following relationship: 3<f1/f<10; 0.3<f2/f<1.2. The distance between the concave mirror 120 and the display screen 110 on the optical axis is L, 20<L<40. Moreover, the inclination angle of the concave mirror 120 on the optical axis of the Fresnel lens 130 is λ, 30°<λ<60°.

2A shows a schematic diagram of a Fresnel lens according to an embodiment of the present invention. As shown in FIG. 2A, the light incident surface 131 of the Fresnel lens 130 is a convex aspheric surface, and its function is to make the light converge and let the axis The outer chief ray is bent toward the optical axis. In this embodiment, the aspheric quadratic coefficients of the light incident surface 131 are: K2 and K4, which satisfy the following relationship: K2<-1, K4<-50; the light exit surface 132 is Toroidal Fresnel surface with positive optical power. Fig. 2B shows a schematic diagram of a common lens equivalent to a Fresnel lens according to an embodiment of the present invention. As shown in Figure 2B, the light incident surface 151 of this ordinary lens 150 is the same convex aspheric surface as the light incident surface 131 shown in Figure 2A, and the light exit surface 152 is exactly the same as the light exit surface 132 shown in Figure 2A. Effective convexity. Comparing the completely equivalent Fresnel lens and the ordinary lens shown in Figure 2A and Figure 2B, it can be seen that, compared with the ordinary lens, the Fresnel lens divides the lens into a series of theoretically infinitely many concentric circles (that is, the Fresnel zone, as shown by the light exit surface 132 in FIG. 2A ) achieves the same optical effect, while saving the amount of materials, effectively reducing the quality and volume of the eyepiece system. In one embodiment of the present invention, the Fresnel lens shown in FIG. 2A is manufactured on a flat substrate, which reduces processing difficulty and improves processing efficiency.

In one embodiment of the present invention, the Fresnel lens 130 shown in FIG. 2A is made of plastic, and the ranges of its refractive index and Abbe number are: 1.45<n<1.70, 50<v<75; specifically, using The plastic material of the E48R model has a refractive index and Abbe number: n=1.531160, v=56.04. By using plastic materials to process and manufacture the Fresnel lens, the processing difficulty and processing cost are further reduced, and the quality of the eyepiece system is reduced at the same time.

Based on the features mentioned above, the eyepiece system shown in Figure 1 achieves a field of view of 50° and is suitable for a 5.5-inch display screen. The light emitted by the display screen is imaged by the eyepiece system and is 5 meters away from the human eye. A magnified virtual image is formed.

FIG. 3 shows a spot diagram of an eyepiece system according to an embodiment of the present invention. The spot diagram ignores the diffraction effect and reflects the imaging geometry of the optical system. In the spot diagram of a large aberration system, the distribution of points can approximately represent the energy distribution of point images. Therefore, in image quality evaluation, the density of the spot diagram can be used to more intuitively reflect and measure the quality of system imaging. It can be seen from Figure 3 that the chromatic aberration of the eyepiece system is not very obvious, and other aberrations are also well corrected, which can meet the needs of users to use the eyepiece system to watch the images displayed on the display screen.

The present invention also provides a head-mounted display, which includes the eyepiece system described in any one of the above embodiments. In one embodiment, the head-mounted display can adjust the focal length of the eyepiece system within a certain range, so that the eyepiece system in the head-mounted display is suitable for short-sighted people; The mode of the lens group, the user can actively adjust the position of the lens group on the optical axis according to their own needs, and the eyepiece system realizes the focal length adjustment according to the user's operation of moving the lens group in the eyepiece system, so that the focal length is suitable for myopic people Human perception. Based on the various parameters of the eyepiece system described above, the eyepiece system of the head-mounted display provided by the present invention can be applied to people whose myopia is below 500 degrees.

It can be seen from the above that the eyepiece system provided by the present invention uses a concave reflector and a lens group to cooperate with each other in the light transmission process, so that the light generated by the display screen converges and enters the human eye, forming an upright and enlarged image at a certain distance in front of the human eye. Virtual image. It has the following beneficial effects: 1. In the process of converging light, the concave reflector bears a part of the optical power of the eyepiece system, which reduces the optical power requirements of the eyepiece system for the lens group, that is, reduces the optical power generated by the lens group. Chromatic aberration; and because the concave mirror does not produce chromatic aberration in the process of converging light, it can greatly reduce the chromatic aberration of the eyepiece system and improve the imaging quality. 2. By using the Fresnel lens as the lens group, the lens material can be greatly saved, and the quality and volume of the eyepiece system can be reduced. 3. The Fresnel lens is processed with a flat base and made of plastic material, which reduces the processing difficulty and cost of the eyepiece system and improves the processing efficiency.

Applying the eyepiece system to the head-mounted display reduces the mass and volume of the head-mounted display, improves the imaging quality of the head-mounted display, reduces the processing difficulty and cost of the head-mounted display, and further provides the ability to adjust the eyepiece system. The focal length function makes the head-mounted display suitable for near-sighted people. The technical solution provided by the present invention greatly improves the experience effect and comfort of the user using the head-mounted display, and provides the user with a more perfect visual experience.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention.

Claims (10)

1. A kind of eyepiece system is characterized in that, this eyepiece system comprises: display screen, concave mirror and positive lens group; The concave reflector is used to reflect the light emitted by the display screen into the positive lens group; The positive lens group is used for refracting the light reflected by the concave mirror into human eyes. 2. The eyepiece system of claim 1, wherein: The positive lens group is a Fresnel lens. 3. The eyepiece system of claim 2, wherein: The reflective surface of the concave reflector is a concave spherical surface; The base of the Fresnel lens is a plane, its light incident surface is a convex aspheric surface, and its light exit surface is an annular Fresnel surface with positive refractive power. 4. The eyepiece system of claim 3, wherein: The aspheric quadratic coefficients of the convex aspheric surface of the Fresnel lens are: K2 and K4, which satisfy the following relationship: K2<-1, K4<-50. 5. eyepiece system as claimed in claim 2, is characterized in that, the focal length of described eyepiece system is f, and the focal length of described concave mirror is f1, and the focal length of described Fresnel lens is f2, satisfy following relation: 3<f1/f<10; 0.3<f2/f<1.2. 6. The eyepiece system according to claim 5, wherein the distance between the concave mirror and the display screen on the optical axis is L, 20<L<40. 7. The eyepiece system according to claim 6, wherein the inclination angle of the concave reflector on the optical axis of the Fresnel lens is λ, 30°<λ<60°. 8. The eyepiece system according to claim 2, wherein the Fresnel lens is made of plastic, and the ranges of its refractive index and Abbe number are respectively: 1.45<n<1.70, 50<v<75. 9. A head-mounted display, characterized in that the head-mounted display comprises the eyepiece system according to any one of claims 1-8. 10. The head-mounted display according to claim 9, wherein the eyepiece system realizes focus adjustment according to the user's operation of moving the lens group.