CN109407301B

CN109407301B - Eyepiece and head-mounted equipment

Info

Publication number: CN109407301B
Application number: CN201811451865.4A
Authority: CN
Inventors: 韩昕彦
Original assignee: Chongqing IQIYI Intelligent Technology Co Ltd
Current assignee: Beijing Dream Bloom Technology Co ltd; Beijing IQIYi Intelligent Entertainment Technology Co Ltd
Priority date: 2018-11-30
Filing date: 2018-11-30
Publication date: 2021-06-15
Anticipated expiration: 2038-11-30
Also published as: CN109407301A

Abstract

The invention provides an eyepiece and a head-mounted device, wherein the eyepiece adopts a biconvex aspheric surface structure, and the curvature of field of a meridian plane of the eyepiece is corrected to be close to a straight line. According to the scheme of the invention, the curvature of field of the meridian plane of the ocular is corrected to be close to a straight line, namely the curvature of field of each field of view is close to zero, and the image surface of the system is close to a plane, so that the aberration characteristic of the ocular is closer to the requirement of the plane display on the optical system, the ocular can clearly image the pixels of the plane display, and the definition of the head-mounted equipment is greatly improved.

Description

Eyepiece and head-mounted equipment

Technical Field

The invention relates to the technical field of optics, in particular to an eyepiece and a head-mounted device.

Background

In recent years, the head-mounted device has been a hot topic, and many application products, such as VR (Virtual Reality) head-mounted device, AR (Augmented Reality) head-mounted device, and MR (Mixed Reality) head-mounted device, are also introduced in the market. The head-mounted device enlarges the image on the display screen of the head-mounted device through the ocular lens and then projects the image on the retina of the human eye to create an interactive virtual environment for the user to generate the immersive sensation, so that the ocular lens design is the key for realizing the immersive sensation of the head-mounted device. In the prior art, a point chart and an MTF curve are mainly looked at in the aspect of eyepiece aberration correction, and a display system realized based on the point chart and the MTF curve cannot ensure the definition of an edge field.

Disclosure of Invention

The invention aims to provide an eyepiece and a head-mounted device.

According to an aspect of the present invention, there is provided an eyepiece in a head-mounted device, wherein the eyepiece has a biconvex aspherical surface structure, and curvature of field of a meridional plane of the eyepiece is corrected to be close to a straight line.

According to another aspect of the invention, there is provided a head-mounted device comprising an eyepiece as described herein.

Compared with the prior art, the invention has the following advantages: the curvature of field of the meridian plane of the ocular is corrected to be close to a straight line, namely the curvature of field of each field of view is close to zero, and the system image surface is close to a plane, so that the aberration characteristic of the ocular is closer to the requirement of the plane display on the optical system, the ocular can clearly image the pixels of the plane display, and the definition of the head-mounted equipment is greatly improved.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:

FIG. 1 is a diagram of the construction of an eyepiece for a preferred embodiment of the present invention;

FIG. 2 is a schematic view of the field curvature of the eyepiece shown in FIG. 1;

FIG. 3 is a view of the corresponding rotational symmetry field aberration data of FIG. 2;

FIG. 4 is a diagram of the construction of an eyepiece for another preferred embodiment of the present invention;

FIG. 5 is a schematic view of the field curvature of the eyepiece shown in FIG. 4;

fig. 6 shows the corresponding rotational symmetry field aberration data of fig. 5.

The same or similar reference numbers in the drawings identify the same or similar elements.

Detailed Description

The present invention is described in further detail below with reference to the attached drawing figures.

The invention provides an eyepiece in a head-mounted device, wherein the eyepiece adopts a biconvex aspheric surface structure, and the curvature of field of a meridian plane of the eyepiece is corrected to be close to a straight line.

The eyepiece focuses the primary aberration correction on curvature of field correction in the meridian plane, wherein the curvature of field of the meridian plane of the eyepiece is corrected to be close to a straight line, i.e., each field of view is close to zero. Because the display screen is a plane, the curvature of field of each field of view is close to zero, and the image surface of the system is close to the plane, so that the ocular lens system can clearly image the pixels of the flat panel display, namely the edge field of view can also clearly image, thereby ensuring the definition of the edge field of view without the phenomenon of fuzzy edge field of view.

Preferably, each field curvature of the eyepiece is greater than-0.02 and less than 0.02.

Preferably, the refractive index of the material used for the eyepiece is 1.45-1.65. For example, materials used for the eyepiece include, but are not limited to, PMMA, E48R, OKP4, and the like.

Preferably, the center thickness of the eyepiece is greater than the edge thickness of the eyepiece, the center thickness of the eyepiece is 11.61mm to 13.8mm (millimeters), and the edge thickness of the eyepiece is 1.86mm to 2.00 mm.

In a preferred implementation, the exit pupil distance of the eyepiece is 15mm, the center thickness is 13.8mm, the edge thickness is 2mm, and the angle of view is 93 °. Preferably, the material used for the eyepiece in this implementation is PMMA.

Fig. 1 is a diagram of an eyepiece according to one embodiment of the present invention, and fig. 2 is a diagram illustrating a field curvature of the eyepiece shown in fig. 1. Wherein, this eyepiece is biconvex aspheric surface structure, adopts PMMA to make, and the technical indicator of this eyepiece mainly includes: the exit pupil distance is 15mm, the center thickness is 13.8mm, the edge thickness is 2mm, and the angle of view is 93 degrees. In a specific implementation, the S1 (i.e., the convex left surface of the eyepiece) aspheric coefficients of the eyepiece are as shown in table 1 below:

TABLE 1

The S2 (i.e., the convex to right surface of the eyepiece) aspheric coefficients for this eyepiece are shown in table 2 below:

TABLE 2

Where R denotes a curvature radius, K denotes a conic coefficient, 2nd denotes an aspheric coefficient of order 2, 4th denotes an aspheric coefficient of order 4, 6th denotes an aspheric coefficient of order 6, 8th denotes an aspheric coefficient of order 8, and 10th denotes an aspheric coefficient of order 10.

Figure 2 is a schematic view of the curvature of field of the eyepiece shown in figure 1, where the curve T shown in figure 2 is the curvature of field of the meridian plane of the eyepiece, and it is apparent that the curve T is nearly coincident with the longitudinal axis, i.e. the curvature of field of the meridian plane is corrected to be close to a straight line. FIG. 3 is a graph of rotational symmetric field aberrations (RELATIVE FIELD HEIGHT) data corresponding to FIG. 2, wherein the first column of data is relative field height (RELATIVE FIELD HEIGHT), the second column of data is image height (IMG HT), the third column of data is lateral focal length (X-FOCUS) at the image surface, and the fourth column of data is longitudinal focal length (Y-FOCUS) at the image surface; it is also evident from the data listed in fig. 3 that the field curvature of each field is almost 0.

In another preferred implementation, the exit pupil distance of the eyepiece is 15mm, the center thickness is 11.61mm, the edge thickness is 1.86mm, and the angle of view is 90 °. Preferably, the material used for the eyepiece in this implementation is OKP.

Fig. 4 is a view showing another example of the eyepiece structure of the present invention. Wherein, this eyepiece is biconvex aspheric surface structure, adopts OKP to make, and the technical indicator of this eyepiece mainly includes: the exit pupil distance is 15mm, the center thickness is 11.61mm, the edge thickness is 1.86mm, and the angle of view is 90 degrees. In a specific implementation, the S1 aspheric coefficients of the eyepiece are as shown in table 3 below:

TABLE 3

The S2 aspheric coefficients for this eyepiece are shown in table 4 below:

TABLE 4

Where R denotes a curvature radius, K denotes a conic coefficient, 2nd denotes an aspheric coefficient of order 2, 4th denotes an aspheric coefficient of order 4, 6th denotes an aspheric coefficient of order 6, 8th denotes an aspheric coefficient of order 8, 10th denotes an aspheric coefficient of order 10, 12th denotes an aspheric coefficient of order 12, 14th denotes an aspheric coefficient of order 14, and 16th denotes an aspheric coefficient of order 16.

Figure 5 is a schematic view of the curvature of field of the eyepiece shown in figure 4, where the curve T shown in figure 5 is the curvature of field of the meridian plane of the eyepiece, and it is apparent that the curve T is nearly coincident with the longitudinal axis, i.e. the curvature of field of the meridian plane is corrected to be close to a straight line. Fig. 6 shows the rotational symmetric field aberrations (rotational symmetric field aberrations) data corresponding to fig. 5, and it is also obvious from the data shown in fig. 6 that the curvature of field of each field is almost 0.

According to the ocular lens, the main aberration correction is focused on the curvature of field correction of the meridian plane, so that the curvature of field of the meridian plane of the ocular lens is corrected to be close to a straight line, namely the curvature of field of each field of view is close to zero, and the image surface of the system is close to a plane, so that the aberration characteristic of the ocular lens is closer to the requirement of a flat panel display on an optical system, and the ocular lens can clearly image the pixels of the flat panel display without increasing the number of lenses.

The invention also provides head-mounted equipment which comprises the eyepiece. According to the head-mounted device disclosed by the invention, pixels of the flat panel display can be clearly imaged, and the definition of the head-mounted device is greatly improved.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned. Furthermore, it is obvious that the word "comprising" does not exclude other elements or steps, and the singular does not exclude the plural. A plurality of units or means recited in the system claims may also be implemented by one unit or means in software or hardware. The terms first, second, etc. are used to denote names, but not any particular order.

Claims

1. An eyepiece in a head-mounted device, wherein the eyepiece is of a biconvex aspherical configuration, and curvature of field of a meridional plane of the eyepiece is corrected to approximate a straight line, wherein each curvature of field of the eyepiece is greater than-0.02 and less than 0.02;

the refractive index of the material adopted by the ocular is 1.45-1.65, the center thickness of the ocular is greater than the edge thickness of the ocular, the center thickness of the ocular is 11.61mm-13.8mm, and the edge thickness of the ocular is 1.86mm-2.00 mm.

2. The eyepiece of claim 1, wherein the eyepiece has an exit pupil distance of 15mm, a center thickness of 13.8mm, an edge thickness of 2mm, and a field angle of 93 °.

3. The eyepiece of claim 2, wherein the material used for the eyepiece is PMMA.

4. The eyepiece of claim 1, wherein the eyepiece has an exit pupil distance of 15mm, a center thickness of 11.61mm, an edge thickness of 1.86mm, and a 90 ° field angle.

5. The eyepiece of claim 4, wherein the eyepiece is made of OKP.

6. A head-mounted device comprising the eyepiece of any of claims 1-5.