Device for generating a 3D light field image

Abstract

A light field generating device, the device displaying a near-eye light field, the device comprising: a scoreboard, wherein the display panel is divided into a plurality of sub-areas, each of the sub-areas displaying a subset of light field information; a projection lens array unit, wherein a plurality of scenes are emitted at a position beyond a common aperture from the sub-regions of the display panel by the projection lens array unit; and a fusion lens unit, wherein light rays passing through the projection lens array unit be focused on an imaging plane to create a three-dimensional real image of a light field, wherein the real image is emitted through an ocular unit into the pupil of the eye to be displayed on the retina and perceived as having been obtained from a location almost infinitely distant.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the generation of light fields, in particular to near-eye viewing, which reduces the existing vergence-accommodation conflict (VAC) for the human eye in most augmented reality (AR), virtual reality (VR) and mixed reality (MR) devices. DESCRIPTION OF THE STATE OF THE ART

[0002] In recent years, virtual reality (VR) or augmented reality (AR) devices such as Google Glasses, Vive, Oculus Rift, and others have all relied on the principle of stereoscopic vision to create a three-dimensional (3D) experience. One of the reasons why they have struggled to gain popularity is the distance to the displays. With a short eye distance, it would be uncomfortable for the human eye to view the screen for extended periods. Since the natural divergence of the eyes does not change the focus, this leads to the well-known integration conflict. This means that the viewer experiences discomfort due to the vergence-accommodation conflict (VAC) after prolonged use of the device.

[0003] US Patent 2020 / 0 166 734 A1 proposes a head-mounted display device with a near-eye light field display device. The proposed near-eye light field display device is equipped with a dual telecentric lens unit to significantly improve the image quality of the near-eye light field display device. However, the sizes of the panel and the optical device are too large to be realized in accordance with the current human technical scale of VR and AR. Another US Patent 7,620,309 B2 proposes a plenoptic camera that obtains a four-dimensional light field by using a microlens array between a main lens and a light-sensitive device. Before the light rays are collected on the light-sensitive device, the microlens array arranged in front of the light-sensitive device can separate the travel paths of the light rays.Without such a microlens array, all light rays in the light field are collected and displayed on the light-sensitive device. However, in a summation process, the angular information in the light field would be lost during the camera's scanning process.

[0004] For cooperation with VR projectors and the development of other visual devices for version 4.0 of the industrial human-machine interface, the development of real-world multi-field display applications of pseudo-eye extension is underway as their market scale expands. To enhance the applications of light field display on the retina in AR and VR, the comprehensive display information on the retina needs to be further improved in terms of the immersive quality of the image to realize the practicality and popularization of light field display. Therefore, the current technology does not meet all user requirements in actual use. SUMMARY OF THE INVENTION

[0005] The main purpose of the present invention is to consider near-eye light field imaging as a process of light field rendering in which an eyepiece unit merges a plurality of scenes output by the device with reduced aberration.

[0006] To achieve the above purpose, the present invention is a light field generating device, the device displaying a near-eye light field; the device comprising a display panel, a projection lens array unit, and a fusion lens unit; the display panel is divided into a plurality of sub-areas; each of the sub-areas displays light field information at each field angle; a plurality of scenes are emitted at a position beyond the common aperture from the sub-areas of the display panel through the projection lens array unit; light rays passing through the projection lens array unit are displayed on an imaging plane to form a three-dimensional real image of the light field; and the real image enters the eye pupil through an eyepiece unit to be displayed on the retina and perceived as being emitted from a nearly infinitely distant location.Accordingly, a novel device for generating a light field is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention will be better understood from the following detailed description of the preferred embodiment according to the present invention in conjunction with the accompanying drawings in which Fig. 1 is the structural view showing the preferred embodiment of the present invention; Fig. 2 is the view showing the light path; Fig. 3 is the view showing the modulation transfer function (MTF); Fig. 4 is the view showing the third-order aberration; Fig. 5 is the structural view showing the virtual reality (VR) application of the present invention; Fig. 6 is the view showing the VR application; and Fig. Figure 7 is the structural view showing the application of augmented reality (AR). DESCRIPTION OF THE PREFERRED EMBODIMENT

[0008] The following description of the preferred embodiment is intended to assist in understanding the features and structures of the present invention.

[0009] The Fig. 1 to Fig. 7 shows a structural view of a preferred embodiment according to the present invention; a view showing the light path; a view showing the MTF; a view showing the third-order aberration; a structural view showing a VR application of the present invention; a view showing the VR application; and a structural view showing an AR application. As shown in the figures, the present invention is a light field generating device 1 including a display panel 11, a projection lens array unit 12, and a fusion lens unit 13, wherein light rays are imaged on an imaging plane 14. Therein, the display panel 11 is divided into a plurality of sub-regions to emit a plurality of scenes.Through the projection lens unit 12, the scenes enter the fusion lens unit 13 to form a three-dimensional (3D) real image of the light field at a position beyond the common barrier; and the real image is emitted into the eye pupil through an eyepiece unit.

[0010] In order to verify the design and control the light field quality perceived by the user, the present invention uses an optical design software "CodeV" to train the light field generation device 1 and to verify the simulation result. The light field generation device 1 in Fig. 1 generates the main light rays in all field angles, which are on the imaging plane 14 in Fig. 2. In a simulation, the present invention uses multiple eye models and simulates the deformations of the eyepiece by adjusting the parameters of the eye models for refocusing. To check the clarity of the displayed light field, the present invention analyzes the modulation transfer function (MTF) in Fig. 3. According to studies on human visual perception using letters as test patterns, the letter visibility of the human eye is 5 arc minutes (arcmin).

[0011] In the preferred embodiment, the diameter of the eyeball is approximately 17 millimeters (mm), and the size of a 5-arc-minute image on the retina is approximately 25 micrometers (µm). Therefore, at least 20 cycles per millimeter (cycles / mm) are required to resolve one letter. Fig. 3, the present invention achieves an MTF of 30% at 20 cycles / mm. The displayed light field thus has a clarity effect, a good distance effect, and a deep field focus.

[0012] An analysis of third-order aberration is given in Fig. 4. When comparing the third-order aberrations of the present invention with the eye models, it is found that the eyepiece unit reduces the aberrations of the light field generating device 1 to a level similar to that of the eye models in which only deformations occur at different field angles. It is also shown in Fig. 4 found that the degree of deformation due to the curvature of the retina is relatively high, and the deformation is indeed an important effect of light fusion. In other words, the present invention achieves good results.

[0013] In one application state, the present invention proposes the light field generating device 1 for the near-eye light field display, wherein the light field generating device 1 uses the eyepiece unit 2 as a light field lens, the structure of which is shown in Fig. 5 and Fig. 6 is shown.

[0014] The light field generating device 1 includes the display panel 11, the projection lens unit 12, and the fusion lens unit 13. The display panel 11 is divided into a plurality of sub-regions. The projection lens array unit 12 is a collimating lens array, wherein the collimating lens array comprises an array of collimating lenses 121; the number of collimating lenses 121 is related to the number of sub-regions of the display panel 11; and each of the collimating lenses 121 comprises a plurality of lenses. The fusion lens unit 13 is a lens unit that fuses and focuses images.Therein, a distance between the display panel 11 and the collimating lens array and a distance between the collimating lens array and the focusing lens unit are related to a focal length of the collimating lens array and a focal length of the focusing lens unit; and an F-number constructed with the projection lens array unit 12 and the fusion lens unit 13 is between 2 and 10.

[0015] When applied to AR, VR, and Mixed Reality (MR), the light field generation device 1 projects the light field, and after passing through the eyepiece unit 2, a collimated near-eye light field is presented to the human eye. Within this field, each of the sub-areas of the display panel 11 in the light field generation device 1 displays information about the light field at each field angle. The collimation lens 121 of the projection lens unit 12 collimates the light rays emitted by the display panel 11 into parallel light rays. The fusion lens unit 13 then converges the light rays passing through the projection lens unit 12 into an imaging plane 14. In operation, each of the sub-areas of the display panel 11 displays a specific scene on the imaging plane 14. The scenes of the sub-areas of the display panel 11 are displayed on the imaging plane 14 and overlap.If the images on the partial areas are all the same, the scenes projected on the imaging plane 14 overlap and approximate each other. Furthermore, the display panel 11 can be a laser beam scanner.

[0016] After passing through the eyepiece unit 2, which comprises a plurality of lenses 21, the light rays emitted by the light field generating device 1 enter the eye pupil 3, where the image projected by the light field generating device 1 is projected onto the retina and perceived as being emitted from a location almost infinitely far away.

[0017] The light field generating device 1 proposed in the present invention can be used not only in a VR application as in Fig. 5, but also in an AR application as in Fig. 7 shown. In Fig.7, the present invention proposes the light field generation device 1, which is a multi-display device for demonstrating near-eye AR and is suitable for displaying the near-eye light field. The light field generation device 1 uses the eyepiece unit 2 as a light field lens. This prior art is designed to use a 45-degree bidirectional dichroic flat glass 4 to reduce the on-axis and off-axis aberration of light rays.

[0018] Thus, the present invention designs a light field generation device for near-eye vision that reduces the existing vergence-accommodation conflict of the human eye (VAC). The present invention considers near-eye light field representation as a process of light field reproduction. An eyepiece unit merges the scenes output by the device and reduces aberration. Using eye models, the 3D perception of the generated light fields can be verified. The proposed device was verified by adjusting the focal length of a camera, proving that it is possible to make AR free of VAC.

[0019] In summary, the present invention is a light field generation device that uses a relay lens module to reproduce a light field for a near-eye VR display device; an eyepiece unit is specifically designed for a light field generation device to fuse the light field captured by a camera array and minimize the on-axis and off-axis aberrations of light rays simultaneously; and the proposed device was verified by adjusting the focal length of a camera to prove the ability to avoid the problem of VAC of the human eye for the realization of AR.

[0020] The preferred embodiment disclosed herein is not intended to unnecessarily limit the scope of the invention. Therefore, simple modifications or variations that are within the scope of the claims and the patent instructions disclosed herein are all within the scope of the present invention. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2020 / 0 166 734 A1

[0003] US 7 620 309 B2

[0003]

Claims

[1] A light field generating device, the device displaying a near-eye light field, the device comprising: a scoreboard, wherein the display panel is divided into a plurality of sub-areas, each of the sub-areas displaying a subset of light field information; a projection lens array unit, wherein a plurality of scenes are emitted at a position beyond a common aperture from the sub-regions of the display panel by the projection lens array unit; and a fusion lens unit, wherein light rays passing through the projection lens array unit be focused on an imaging plane to create a three-dimensional real image of a light field, wherein the real image is emitted through an ocular unit into the pupil of the eye to be displayed on the retina and perceived as having been obtained from a location almost infinitely distant. [2] The apparatus of claim 1, wherein one of the portions of the display panel displays a particular scene on an image plane. [3] Apparatus according to claim 2, wherein the scenes of the partial areas of the display panel are displayed in the image plane and overlap each other. [4] Device according to claim 3, wherein in all images on the partial areas of the display panel the scenes broadcast on the image plane can be displayed overlapping and approximating each other. [5] Device according to claim 1, wherein the fusion lens unit is a focusing lens unit; and the projection lens array unit is a collimating lens array; and wherein the collimating lens array comprises an array of collimating lenses; each of the collimating lenses comprises a plurality of lenses; and the number of collimating lenses is related to the number of subregions of the display panel. [6] The apparatus according to claim 5, wherein a distance between a display panel and the collimating lens array and a distance between the collimating lens array and the focusing lens unit are related to a focal length of the collimating lens array and a focal length of the focusing lens unit. [7] The apparatus according to claim 1, wherein an aperture number achieved by the projection lens array unit and the focusing lens unit is between 2 and 10. [8] A light field generating device, the device displaying a near-eye light field, and the device comprising a laser beam scanner, wherein the laser beam scanner is divided into a plurality of sub-areas; and each of the sub-areas displays a subset of light field information; a projection lens array unit, wherein a plurality of scenes are emitted at a position beyond a common aperture from the sub-regions of the laser beam scanner by the projection lens array unit; and a fusion lens unit, wherein rays passing through the projection lens array unit are focused onto an imaging plane to produce a three-dimensional real image of a light field, wherein the real image is emitted through an ocular unit into the pupil of the eye to be displayed on the retina and perceived as having been obtained from a location almost infinitely distant. [9] The apparatus of claim 8, wherein each of the partial areas of the laser beam scanner displays a particular one of the scenes on an imaging plane. [10] The apparatus of claim 9, wherein the scenes of the partial areas of the laser beam scanner are displayed on the imaging plane and overlap each other. [11] Device according to claim 10, wherein in all images on the partial areas of the laser beam scanner, the scenes emitted on the imaging plane can be displayed overlapping and approximating each other. [12] Device according to claim 8, wherein the fusion lens unit is a focusing lens unit; and the projection lens unit is a collimating lens array; and wherein the collimation lens array comprises an array of collimation lenses; each of the collimation lenses comprises a plurality of lenses; and the number of collimation lenses is related to the number of sub-areas of the laser beam scanner. [13] The apparatus of claim 12, wherein a distance between a display panel and the collimating lens array and a distance between the collimating lens array and the focusing lens unit are related to a focal length of the collimating lens array and a focal length of the focusing lens unit. [14] The device according to claim 8, wherein an aperture number achieved by the projection lens unit and the focusing lens unit is between 2 and 10.

Images