Device for generating a three-dimensional light field image

Abstract

Device for Generating a Three-Dimensional Light Field Image. The invention relates to a device (1) for generating a real three-dimensional (3D) image. A display panel (11) is divided into several sub-zones for emitting scenes. Via a projection lens array unit (12), the scenes enter a fusion lens unit (13) to form a real light field image at a position beyond a common barrier. Through an eyepiece unit, the image is emitted to a human eye. Thus, the present invention provides a device (1) for near-eye viewing, which reduces the conflict between vergence and accommodation (VAC) existing in most augmented reality and mixed reality devices. In this device, the near-eye light field display is a light field reproduction process, which fuses the scenes and reduces aberration.Figure to be published with the abbreviation: Figure 1.

Description

Title of the invention: Device for generating a three-dimensional light field image Technical field of the invention

[0001] The present invention relates to the generation of a light field; more particularly, near-eye viewing, which reduces the conflict between vergence and accommodation (VAC) existing for the human eye in most augmented reality (AR), virtual reality (VR) and mixed reality (MR) devices. Description of the prior art

[0002] In recent years, virtual reality (VR) or augmented reality (AR) devices like Google Glass®, Vive®, Oculus Rift®, etc. are all based on the principle of stereo vision to produce three-dimensional (3D) perception. One of the reasons why it is difficult to gain popularity is the distance from the display devices. With a short eye relief, the human eye would not be comfortable for long-term viewing. Also, since the natural divergence of the eyes does not change the adjustment, this leads to the well-known integration conflict. This means that the conflict between vergence and accommodation (VAC) will make the viewer feel nauseous after using the device for a long time.

[0003] A US patent US 2020 / 0166734 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 greatly improve the image quality of the near-eye light field display device. However, the sizes of its panel and optical device are too large to be realized in accordance with the current ergonomic size of VR and AR. Another US patent US 7620309 B2 proposes a plenoptic camera, which obtains a four-dimensional light field by inserting a microlens array between a main lens and a photosensitive device. Before collecting light rays on the photosensitive device, the microlens array placed in front of the photosensitive device can separate the traveling paths of the light rays.In the absence of such a microlens array, all light rays in the light field would be collected and displayed on the photosensitive device. But a summing process would lose the angular information in the light field during a camera sampling process.

[0004] To cooperate with VR projectors and with the development of other devices visuals for version 4.0 of an industrial human-machine interface, real-world multi-field display applications of pseudo-eye expansion are beginning to be developed as their market scales take off. To improve retinal light field imaging applications in AR and VR, the comprehensive retinal display information needs to be further improved with respect to immersive image quality to realize the feasibility and popularization of light field vision. Therefore, the prior art does not meet all user demands in actual use. Summary of the invention

[0005] The main objective of the present invention is to consider the field display light near the eye as a light field reproduction process, where an eyepiece unit fuses a plurality of scenes emitted by the device with reduced aberration.

[0006] To achieve the above objective, the present invention provides a light field generating device, said device being configured to display a light field near an eye, said device comprising: a display panel, wherein said display panel is divided into a plurality of sub-areas, and each of said sub-areas is configured to display sub-set light field information; a projection lens array unit, wherein a plurality of scenes are output to a position beyond a common diaphragm from said sub-areas of said display panel through said projection lens array unit;and a fusion lens unit, in which light rays passing through said projection lens array unit are focused onto an imaging plane to form a three-dimensional light field real image, wherein said real image is emitted into the pupil of the eye through an eyepiece unit to be displayed on the retina and perceived as being obtained from a location almost infinitely distant. ;

[0007] According to a particular characteristic of the invention, any one of said sub-areas of said display panel is configured to display a designated scene from among said scenes on the imaging plane.

[0008] According to a particular characteristic of the invention, said scenes of said sub-areas of said display panel are displayed on said imaging plane and overlap each other.

[0009] According to a particular characteristic of the invention, with all the images on said sub-areas of said display panel, said scenes emitted on said imaging plane are able to overlap and move closer to each other.

[0010] According to a particular feature of the invention, said fusion lens unit is a focusing lens unit; and said projection lens array unit is a collimating lens array; and each of said collimating lenses comprises a plurality of lenses; and the number of said collimating lenses is related to the number of said sub-areas of said display panel.

[0011] According to a particular characteristic of the invention, a distance between the display panel and said collimating lens array and a distance between said collimating lens array and said focusing lens unit are related to a focal length of said collimating lens array and to a focal length of said focusing lens unit.

[0012] According to a particular characteristic of the invention, an aperture number obtained with said projection lens array unit and said fusion lens unit is between 2 and 10.

[0013] According to a particular characteristic of the invention, the display panel is a laser beam scanning device. Brief description of the drawings

[0014] The present invention will be better understood from the following detailed description of the preferred embodiment according to the present invention, taken in conjunction with the accompanying drawings, in which

[0015] [Fig. 1] is a structural view showing the preferred embodiment according to the present invention;

[0016] [Fig.2] is a view showing the light path;

[0017] [Fig.3] is a view showing the modulation transfer function (MTF);

[0018] [Fig.4] is a view showing third-order aberration;

[0019] [Fig.5] is a structural view showing the virtual reality (VR) application of the present invention;

[0020] [Fig.6] is a view showing the VR application; and

[0021] [Fig.7] is a structural view showing the augmented reality (AR) application. Description of the preferred embodiment

[0022] The following description of the preferred embodiment is provided to understand the features and structures of the present invention.

[0023] Refer to Figures 1 to 7, which are a structural view showing a preferred embodiment according to the present invention; a view showing a light path; a view showing the MTF; a view showing the third-order aberration; a structural view showing an RV application of the present invention; a view showing the RV application; and a structural view showing an RA application. As shown in the Figures, the present invention is a field generating device A light field 1, comprising a display panel 11, a projection lens array unit 12 and a fusion lens unit 13, light rays being displayed on an imaging plane 14. In this, the display panel 11 is divided into a plurality of sub-areas for emitting a plurality of scenes. Via the projection lens array unit 12, the scenes enter the fusion lens unit 13 to form a three-dimensional (3D) real image of a light field at a position beyond a common barrier; and the real image is emitted into the pupil of the eye through an eyepiece unit.

[0024] To verify the design and control the light field quality perceived by the user, the present invention uses optical design software 'CodeV' to practice the light field generating device 1 with verification of the simulation result. The light field generating device 1 of [Fig.l] makes the main light rays at all field angles approach each other on the imaging plane 14 of [Fig.2]. In a simulation, the present invention uses several eye models and simulates the eyepiece deformations by adjusting the parameters of the eye models for refocusing. To verify the clarity of the displayed light field, the present invention analyzes the modulation transfer function (MTF) of [Fig.3]. According to human visual perception studies using letters as test models, the vision of letters by a human eye is 5 arc minutes (arcmin).

[0025] In the preferred embodiment, the eyeball diameter is about 17 millimeters (mm), and the size of a 5 arc-minute image on the retina is about 25 microns (pm). Therefore, it takes at least 20 cycles per millimeter (cycles / mm) to resolve a letter. In [Fig. 3], under 20 cycles / mm, the present invention achieves 30% of the MTF. Thus, the displayed light field has a clarity effect, a good distance effect, and deep field focusing.

[0026] Furthermore, an analysis of the third-order aberration is shown in [Fig. 4]. By comparing the third-order aberrations of the present invention and eye models, it is found that the eyepiece unit reduces the aberrations of the light field generating device 1 to a level similar to those of the eye models, where only distortions exist in various field angles. It is also seen from [Fig. 4] that the degrees of distortions are relatively high due to the curvature of the retina, where the distortions are actually a significant effect of light merging. In other words, the present invention achieves good effects.

[0027] In a state of use, the present invention provides the light field generating device 1 for near-eye light field display, the light field generating device 1 using the eyepiece unit 2 as a light field lens with its structure shown in [Fig.5] and [Fig.6].

[0028] The light field generating device 1 comprises the display panel 11, the projection lens array unit 12, and the fusion lens unit 13. The display panel 11 is divided into a plurality of sub-areas. The projection lens array unit 12 is a collimating lens array, the collimating lens array comprising a collimating lens array 121; the number of collimating lenses 121 is related to the number of sub-areas 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.Here, 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 (i.e., the merging 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 (or aperture number) constructed with the projection lens array unit 12 and the merging lens unit 13 is between 2 and 10.

[0029] When applied to AR, VR, and mixed reality (MR), the light field generating device 1 projects the light field; and, after passing through the eyepiece unit 2, a collimated light field near the eye is shown to the human eye. Here, each of the sub-areas of the display panel 11 in the light field generating device 1 shows information of the light field at each field angle. The collimating lens 121 of the projection lens array unit 12 collimates the emitted light rays into parallel light rays from the display panel 11. The merging lens unit 13 then converges the light rays passing through the projection lens array unit 12 onto an imaging plane 14. In the use state, any one of the sub-areas of the display panel 11 displays a designated scene from among the scenes 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 each other. When the images on the sub-areas are all the same, the scenes output on the imaging plane 14 overlap and move closer to each other. Furthermore, the display panel 11 may be a laser beam scanning device.

[0030] 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 pupil of the eye 3, the image projected by the light field generating device 1 being projected onto the retina and perceived as being emitted from a location almost infinitely distant.

[0031] The light field generating device 1 provided in the present invention can be used not only in a VR application as shown in [Fig.5], but also in an AR application as shown in [Fig.7]. In [Fig.7], The present invention provides the light field generating device 1, which is a multi-display device for near-eye AR demonstration and suitable for displaying a near-eye light field. The light field generating device 1 uses the eyepiece unit 2 as a light field lens. This state of use is designed to use a 45-degree bidirectional dichroic flat glass 4 to reduce the aberration of on-axis and off-axis light rays.

[0032] Thus, the present invention designs a light field generation device for near-eye viewing, which reduces the conflict between vergence and accommodation (VAC) of a human eye. The present invention regards near-eye light field display as a light field reproduction process. An eyepiece unit fuses scenes output from the device and reduces aberration. By using eye models, 3D perceptions of the generated light fields can be verified. The proposed device has been verified by adjusting the focal length of a camera, which proves that it is possible to make AR without VAC.

[0033] In summary, the present invention is a light field generating device, in which a relay lens module is used to reproduce a light field for a near-eye VR display device; an eyepiece unit is specially designed for a light field generating device so as to merge the light field captured by a camera array and minimize the aberrations of on-axis and off-axis light rays at the same time; and the proposed device has been verified by adjusting the focal length of a camera to prove the ability to avoid the VAC problem of the human eye to realize AR.

[0034] The preferred embodiment disclosed herein is not intended to unnecessarily limit the scope of the invention. Therefore, simple modifications or variations are all included within the scope of the present invention.

Claims

Claims

1. A light field generating device (1), characterized in that said device (1) is configured to display a light field near an eye, said device (1) comprising: a display panel (11), wherein said display panel (11) is divided into a plurality of sub-areas for outputting a plurality of scenes; and each of said sub-areas is configured to display sub-set light field information simultaneously; a projection lens array unit (12), wherein the plurality of scenes are output to a position beyond a common aperture from said sub-areas of said display panel (11) through said projection lens array unit (12);and a fusion lens unit (13), in which light rays passing through said projection lens array unit (12) are focused and converged on an imaging plane (14) to form a three-dimensional light field real image, wherein said real image is emitted into the pupil of the eye (3) through an eyepiece unit (2) to be displayed on the retina and perceived as being obtained from a location almost infinitely distant.;

2. Device (1) according to claim 1, characterized in that any one of said sub-areas of said display panel (11) is configured to display a designated scene from among said scenes on the imaging plane (14).

3. Device (1) according to claim 2, characterized in that said scenes of said sub-areas of said display panel (11) are displayed on said imaging plane (14) and overlap each other.

4. Device (1) according to claim 3, characterized in that, with all the images on said sub-areas of said display panel (11), said scenes emitted on said imaging plane (14) are able to overlap and move closer to each other.

5. A device (1) according to claim 1, characterized in that said fusing lens unit (13) is a focusing lens unit; and said projection lens array unit (12) is a collimating lens array (121); and wherein each of said collimating lenses (121) comprises a plurality of lenses; and the number of said collimating lenses (121) is related to the number of said sub-areas of said display panel (11).

6. Device (1) according to claim 5, characterized in that a distance between the display panel (11) and said collimating lens array (121) and a distance between said collimating lens array (121) and said focusing lens unit are related to a focal length of said collimating lens array (121) and a focal length of said focusing lens unit.

7. Device (1) according to claim 1, characterized in that an aperture number obtained with said projection lens array unit (12) and said fusion lens unit (13) is between 2 and 10.

8. Device (1) according to one of claims 1 to 7, characterized in that the display panel (11) is a laser beam scanning device.

Images