CN113109946A - Near-to-eye display device and near-to-eye display system - Google Patents

Abstract

The present disclosure provides a near-eye display device and a near-eye display system. The near-eye display device includes: the image acquisition assembly comprises an image sensor and a first lens, wherein the image sensor is used for acquiring image information through the first lens; the image display assembly comprises a display and a second lens, the display is used for displaying a target image according to the image information, and the second lens is arranged on the light emergent side of the display and used for shaping the target image displayed by the display; the first lens and/or the second lens are/is a refraction and diffraction mixed lens, and the refraction and diffraction mixed lens comprises opposite diffraction lens surfaces and refraction lens surfaces. The present disclosure enables simplification of the optical path system.

Description

Near-to-eye display device and near-to-eye display system

Technical Field

The present disclosure relates to the field of display technologies, and in particular, to a near-eye display device and a near-eye display system.

Background

MR (Mixed Reality) technology is a further development of virtual Reality technology, which can enhance the Reality of user experience by introducing real scene information into a virtual environment and building an interactive feedback information loop among the virtual world, the real world and the user. The near-eye display device based on the MR technology generally acquires an image by an image acquisition component and displays the image by a display. However, in order to achieve the effect of dispersion cancellation, a double cemented achromatic lens group or a multi-lens group is often used, which leads to a complicated optical path system.

Disclosure of Invention

An object of the present disclosure is to provide a near-eye display device and a near-eye display system, which can simplify an optical path system.

According to an aspect of the present disclosure, there is provided a near-eye display device including:

the image acquisition assembly comprises an image sensor and a first lens, wherein the image sensor is used for acquiring image information through the first lens;

the image display assembly comprises a display and a second lens, the display is used for displaying a target image according to the image information, and the second lens is arranged on the light emergent side of the display and used for shaping the target image displayed by the display;

the first lens and/or the second lens are/is a refraction and diffraction mixed lens, and the refraction and diffraction mixed lens comprises opposite diffraction lens surfaces and refraction lens surfaces.

Furthermore, the first lens and the second lens are both refraction and diffraction mixed lenses, a diffraction lens surface of the first lens is an incident light side of the image acquisition assembly, and a diffraction lens surface of the second lens faces an emergent light side of the display.

Further, the reverse optical path distortion of the second lens is equal to the distortion of the first lens at each field angle.

Further, the diffractive lens surface includes a basal surface and a grating structure provided on the basal surface.

Further, the refractive lens surface or the basal surface is an even-order aspherical surface.

Further, the surface type equation of the even aspheric surface is as follows:

wherein Z is the axial distance between any point on the even aspheric surface and the tangent plane of the vertex of the even aspheric surface, r is the radial distance between any point on the even aspheric surface and the main optical axis of the refraction and diffraction mixed lens, c is the curvature of the vertex of the even aspheric surface, k is the coefficient of a quadric surface, i is a positive integer, A is the axial distance between any point on the even aspheric surface and the tangent plane of the vertex of the even aspheric surface, and_2iare aspheric coefficients of order 2 i.

Further, the phase equation of the grating structure is:

wherein,

for phase modulation of incident light by the diffractive lens, r is the radial distance of any point on the even-order aspheric surface relative to the main optical axis of the refraction-diffraction mixed lens, i is a positive integer, C_2iIs the phase coefficient.

Further, a refractive index of a material of the first lens or a refractive index of a material of the second lens is 1.49.

Further, the image acquisition assembly further comprises:

and the infrared filter is arranged on the light emergent side of the first lens.

According to one aspect of the present disclosure, a near-eye display system is provided, including the near-eye display device described above.

The utility model discloses a near-to-eye display device and near-to-eye display system, image sensor obtains image information through first camera lens, the display shows the target image according to the image information that image sensor obtained, in order to show, locate the second camera lens of display light-emitting side can carry out the plastic to the target image that the display shows, because first camera lens and/or second camera lens are refraction and diffraction hybrid lens, and refraction and diffraction hybrid lens includes opposite diffraction lens face and refraction lens face, thereby can obtain the effect of apochromatic through the mutual offset of the negative dispersion characteristic of diffraction lens face and the positive dispersion characteristic of refraction lens face, and then can replace two veneer achromatism lens groups or multi-disc lens group through single lens, optical path system has been simplified.

Drawings

Fig. 1 is a block diagram of a near-eye display device of an embodiment of the present disclosure.

Fig. 2 is a schematic diagram of a near-eye display device first lens side of an embodiment of the disclosure.

Fig. 3 is a schematic diagram of an image capture assembly of a near-eye display device of an embodiment of the present disclosure.

Fig. 4 is a dispersion map of a first lens of an embodiment of the present disclosure.

Fig. 5 is an axial aberration diagram of the first lens of the embodiment of the present disclosure.

Fig. 6 is a schematic diagram of a near-eye display device of an embodiment of the disclosure on a second lens side.

Fig. 7 is a schematic diagram of an image display assembly of a near-eye display device of an embodiment of the present disclosure.

Fig. 8 is a dispersion map of the second lens of the embodiment of the present disclosure.

Fig. 9 is an axial aberration diagram of the second lens of the embodiment of the present disclosure.

Fig. 10-12 are schematic diagrams of reverse optical path distortion of the second lens and distortion of the first lens of embodiments of the present disclosure.

Description of reference numerals: 1. a first lens; 2. an image sensor; 3. a display; 4. a second lens; 5. an infrared filter.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Rather, they are merely examples of devices consistent with certain aspects of the present disclosure, as detailed in the appended claims.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and similar terms in the description and claims does not indicate any order, quantity, or importance, but rather is used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. "plurality" or "a number" means two or more. The word "comprising" or "comprises", and the like, means that the element or item listed as preceding "comprising" or "includes" covers the element or item listed as following "comprising" or "includes" and its equivalents, and does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. As used in this disclosure and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

The disclosed embodiments provide a near-eye display device. As shown in fig. 1, the near-eye display device may include an image capture assembly and an image display assembly, wherein:

the image capturing assembly includes an image sensor 2 and a first lens 1. The image sensor 2 is used to acquire image information through the first lens 1. The image display assembly includes a display 3 and a second lens 4. The display 3 is used to display a target image based on the image information acquired by the image sensor 2. The second lens 4 is disposed on the light emitting side of the display 3 and is used for shaping a target image displayed by the display 3. The first lens 1 and/or the second lens 4 are/is a refraction-diffraction mixed lens. The diffractive hybrid lens includes opposing diffractive and refractive lens faces.

According to the near-eye display device of the embodiment of the disclosure, the image sensor 2 acquires image information through the first lens 1, the display 3 displays a target image according to the image information acquired by the image sensor 2 for displaying, and the second lens 4 arranged on the light-emitting side of the display 3 can shape the target image displayed by the display 3, because the first lens 1 and/or the second lens 4 are/is a refraction and diffraction mixed lens, and the refraction and diffraction mixed lens comprises opposite diffraction lens surfaces and refraction lens surfaces, the negative dispersion characteristic of the diffraction lens surface and the positive dispersion characteristic of the refraction lens surface can be mutually offset to obtain the effect of dispersion elimination, and then a single lens can replace a double-cemented achromatism lens group or a multi-lens group, thereby simplifying an optical path system.

The following describes each part of the near-eye display device according to the embodiment of the present disclosure in detail:

as shown in fig. 2 and 3, the image capturing assembly is used for acquiring image information of an external object. The image capturing assembly may include an image sensor 2 and a first lens 1. Light of an external object may pass through the first lens 1 and reach the image sensor 2, and the image sensor 2 is configured to generate image information according to the light reaching the image sensor 2. For example, the image capturing component may be a camera, but the embodiment of the disclosure is not limited thereto. Furthermore, the image acquisition assembly may comprise an infrared filter 5. The infrared filter 5 may be disposed between the image sensor 2 and the first lens 1, so that light rays of an external object pass through the first lens 1, then pass through the infrared filter 5, and then reach the image sensor 2. The refractive index of the material of the infrared filter 5 may be 1.52 and the abbe number may be 58.96, but the disclosed embodiments are not limited thereto. The refractive index of the material of the first lens 1 may be 1.49 and the abbe number may be 57.44, but the embodiments of the present disclosure are not limited thereto. For example, the material of the first lens 1 may be polymethyl methacrylate (PMMA). In addition, the number of the first lenses 1 may be two and coaxial with both eyes of the user.

As shown in fig. 2 and 3, the first lens 1 of the image capturing assembly may be a diffractive-refractive hybrid lens. The diffractive hybrid lens includes two opposing lens faces. The two lens surfaces are a diffractive lens surface and a refractive lens surface, respectively. The diffractive lens surface and the refractive lens surface are arranged oppositely in the direction of the main optical axis of the refraction-diffraction mixed lens. The negative dispersion characteristic of the diffractive lens surface and the positive dispersion characteristic of the refractive lens surface cancel each other out to obtain the effect of dispersion elimination. As shown in fig. 4, the maximum dispersion of the first lens 1 is about 0.5 μm, which is smaller than the pixel size of most current camera sensor chips, and is hardly recognizable by human eyes. As shown in fig. 5, the ordinate of the Coordinate system in fig. 5 is Normalized (Normalized horizontal Coordinate), the line L1 is the axial aberration curve at a long wavelength, L2 is the axial aberration curve at a central wavelength, and L3 is the axial aberration curve at a short wavelength, which indicates that the imaging effect of the first lens 1 is better. The diffractive lens surface of the first lens 1 is the light incident side of the image capturing assembly, that is, the light of the external object enters from the diffractive lens surface of the first lens 1 and exits from the refractive lens surface of the first lens 1, and the exiting light can reach the image sensor 2. In other embodiments of the present disclosure, the refractive lens surface of the first lens 1 may be a light incident side of the image capturing component, that is, light of an external object enters from the refractive lens surface of the first lens 1 and exits from the diffractive lens surface of the first lens 1, and the exiting light may reach the image sensor 2. The diffractive lens surface of the first lens 1 includes a ground surface and a grating structure provided on the ground surface. The grating structure can be obtained by etching the substrate surface. The refractive lens surface of the first lens 1 may be an even-order aspheric surface, and the base surface of the diffractive lens surface of the first lens 1 may be an even-order aspheric surface, but the embodiments of the present disclosure are not limited thereto.

As shown in fig. 6 and 7, the image display assembly is used for displaying. The image display assembly includes a display 3 and a second lens 4. The display 3 may be communicatively connected to the image sensor 2 to receive image information acquired by the image sensor 2. The display 3 may be wirelessly connected to the image sensor 2, for example, a bluetooth connection, a 3G connection, a 4G connection, a 5G connection, etc., but the present disclosure is not limited thereto, and the display 3 may also be connected to the image sensor 2 through a data line. Wherein, under the condition of display 3 and image sensor 2 wireless connection, foretell image acquisition subassembly can be among camera equipment such as unmanned aerial vehicle. The display 3 is used to display a target image based on the image information acquired by the image sensor 2. The second lens 4 is disposed on the light emitting side of the display 3 and is used for shaping a target image displayed by the display 3. The shaping of the target image by the second lens 4 may include adjusting the shape of the target image to an image suitable for human eye observation, and reducing distortion of the target image, and of course, the shaping may also include enlarging the target image to obtain an image suitable for human eye observation, but the disclosure is not limited thereto, and the shaping may also include reducing chromatic dispersion of the target image. The refractive index of the material of the second lens 4 may be 1.49, and the abbe number may be 57.44, but the embodiment of the present disclosure is not limited thereto. For example, the material of the second lens 4 may be polymethyl methacrylate (PMMA).

As shown in fig. 6 and 7, the second lens 4 of the image display assembly may be a diffractive hybrid lens. The diffractive hybrid lens includes two opposing lens faces. The two lens surfaces are a diffractive lens surface and a refractive lens surface, respectively. The diffractive lens surface and the refractive lens surface are arranged oppositely in the direction of the main optical axis of the refraction-diffraction mixed lens. The negative dispersion characteristic of the diffractive lens surface and the positive dispersion characteristic of the refractive lens surface cancel each other out to obtain the effect of dispersion elimination. As shown in fig. 8, the maximum dispersion of the second lens 4 is about 40 μm. Taking a 3.5-inch 2K-resolution display 3 as an example, the pixel size is about 29 μm, and the maximum dispersion does not exceed 2 pixels when the second lens 4 is used with the display 3, which is difficult for human eyes to recognize. As shown in fig. 9, the ordinate of the Coordinate system in fig. 9 is Normalized (Normalized horizontal Coordinate), the line L4 is the axial aberration curve at the short wavelength, the line L5 is the axial aberration curve at the long wavelength, and the line L6 is the axial aberration curve at the central wavelength, which shows that the imaging effect of the second lens 4 is better. The diffractive lens surface of the second lens 4 faces the light exit side of the display 3, and the refractive lens surface of the second lens 4 faces away from the light exit side of the display 3, that is, the refractive lens surface of the second lens 4 faces human eyes. The diffractive lens surface of the second lens 4 includes a ground surface and a grating structure provided on the ground surface. The grating structure can be obtained by etching the substrate surface. The refractive lens surface of the second lens 4 may be an even-order aspheric surface, and the base surface of the diffractive lens surface of the second lens 4 may be an even-order aspheric surface, but the embodiments of the present disclosure are not limited thereto.

The surface equation of the even aspheric surface may be:

the phase equation of the grating structure is as follows:

in the above surface equation and phase equation, Z is an axial distance between any point on the even aspheric surface and a tangent plane of a vertex of the even aspheric surface, r is a radial distance between any point on the even aspheric surface and a principal optical axis of the hybrid diffractive/refractive lens, c is a curvature of the vertex of the even aspheric surface, k is a conic coefficient, i is a positive integer, a is a positive integer, and_2iis an aspheric coefficient of order 2i,

for phase modulation of incident light by the diffractive lens, r is the radial distance of any point on the even-order aspheric surface relative to the main optical axis of the refraction-diffraction mixed lens, i is a positive integer, C_2iIs the phase coefficient.

For the first lens 1, detailed parameters are as shown in tables 1, 2 and 3, where f is the focal length, TL is the total system length, FOV is the field angle, R is the curvature radius, and T is the lens thickness. Wherein, the total system length of the first lens 1 is the distance from the diaphragm of the first lens 1 to the image sensor 2.

TABLE 1

TABLE 2

TABLE 3

The detailed parameters of the infrared filter 5 are shown in table 4.

TABLE 4

For the second lens 4, the detailed parameters are as in tables 5, 6, and 7. Wherein the total system length of the second lens 4 is the distance from the diaphragm of the second lens 4 to the display 3.

TABLE 5

TABLE 6

TABLE 7

The reverse optical path distortion of the second lens 4 is equal to the distortion of the first lens 1 at each viewing angle. Taking the example that the diffractive lens surface of the second lens 4 faces the light-emitting side of the display 3 and the refractive lens surface of the second lens 4 faces away from the light-emitting side of the display 3, in the using process, the light emitted by the display 3 sequentially passes through the diffractive lens surface of the second lens 4 and the refractive lens surface of the second lens 4 and reaches the diaphragm. The above-mentioned reverse optical path of the second lens 4 refers to: the light beam passes through the refractive lens surface of the second lens 4 and the diffractive lens surface of the second lens 4 in this order from the stop, and reaches the display 3. According to the reversible principle of the optical path, an optical system is combined with a reverse optical path system thereof to obtain a system without aberration; if the distortion of the other optical system is identical to that of the reverse optical system at each field of view, the distortion of the optical system and the optical system can be completely offset after combination, and a distortion-free system can be obtained. Therefore, the distortion of the reverse optical path of the second lens 4 is equal to the distortion of the first lens 1 at each view angle, so that the distortion of the second lens 4 combined with the first lens 1 can be completely offset, and the distortion-free effect can be realized without software processing. Fig. 10 is a schematic view of distortion at a short wavelength, fig. 11 is a schematic view of distortion at a center wavelength, and fig. 12 is a schematic view of distortion at a long wavelength. As shown in fig. 10 to 12, the reverse optical path distortion of the second lens 4 is equal to the distortion of the first lens 1 at each field angle at three wavelengths.

The embodiment of the disclosure also provides a near-eye display system. The eye-only display system may comprise a near-eye display device as described in any of the above embodiments. The near-eye display system and the near-eye display device provided by the embodiment of the disclosure belong to the same inventive concept, and descriptions of beneficial effects can be referred to each other and are not repeated.

Although the present disclosure has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure.

Claims (10)

1. A near-eye display device, comprising:

the image acquisition assembly comprises an image sensor and a first lens, wherein the image sensor is used for acquiring image information through the first lens;

the image display assembly comprises a display and a second lens, the display is used for displaying a target image according to the image information, and the second lens is arranged on the light emergent side of the display and used for shaping the target image displayed by the display;

the first lens and/or the second lens are/is a refraction and diffraction mixed lens, and the refraction and diffraction mixed lens comprises opposite diffraction lens surfaces and refraction lens surfaces.

2. The near-eye display device of claim 1, wherein the first lens and the second lens are diffractive-refractive hybrid lenses, a diffractive lens surface of the first lens is an incident light side of the image capturing assembly, and a diffractive lens surface of the second lens faces an emergent light side of the display.

3. The near-eye display device of claim 1, wherein a reverse optical path distortion of the second lens is equal to a distortion of the first lens at each field angle.

4. The near-eye display device of claim 1, wherein the diffractive lens surface comprises a base surface and a grating structure provided on the base surface.

5. The near-eye display device of claim 4 wherein the refractive lens surface or the base surface is an even aspheric surface.

6. The near-to-eye display device of claim 5 wherein the even aspheric surface has a surface form equation of:

wherein Z is the axial distance between any point on the even aspheric surface and the tangent plane of the vertex of the even aspheric surface, r is the radial distance between any point on the even aspheric surface and the main optical axis of the refraction and diffraction mixed lens, c is the curvature of the vertex of the even aspheric surface, k is the coefficient of a quadric surface, i is a positive integer, A is the axial distance between any point on the even aspheric surface and the tangent plane of the vertex of the even aspheric surface, and_2iare aspheric coefficients of order 2 i.

7. A near-to-eye display device as claimed in claim 5 wherein the phase equation for the grating structure is:

wherein,

for the phase modulation of the diffraction lens facing the incident light, r is the radial distance of any point on the even aspheric surface relative to the main optical axis of the refraction and diffraction mixed lens, i is a positive integer, C_2iIs the phase coefficient.

8. The near-eye display device of claim 1, wherein a refractive index of a material of the first lens or a refractive index of a material of the second lens is 1.49.

9. The near-eye display device of claim 1 wherein the image capture assembly further comprises:

and the infrared filter is arranged on the light emergent side of the first lens.

10. A near-eye display system comprising the near-eye display device of any one of claims 1-9.

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