Device and method for generating a 3D light field

Patent metadata

Field	Value
Publication number	US-11409118-B2
Application number	US-201916664409-A
Country	US
Kind code	B2
Filing date	Oct 25, 2019
Priority date	Apr 26, 2017
Publication date	Aug 9, 2022
Grant date	Aug 9, 2022

Abstract

The present disclosure provides a device for generating a 3D light field. The device comprises a first lens having a fixed focal length, and an imaging element arranged to send light into the first lens. The imaging element is configured to send the light from different positions within a defined distance on the optical axis of the first lens, in order to produce different depth layers of the 3D light field within a frame duration.

First claim

What is claimed is:

1. A device for generating a 3-dimensional, 3D, light field, comprising:
a first lens having a fixed focal length, and
an imaging element arranged to send light into the first lens,
wherein the imaging element is configured to move to different positions within a defined distance on an optical axis of the first lens, and to send the light from the different positions in order to produce different depth layers of the 3D light field within a frame duration.

2. The device according to claim 1 , wherein:
the imaging element is a liquid crystal arrangement including a plurality of liquid crystal layers arranged at the different positions, and
each of the liquid crystal layers is configured to be enabled or disabled according to a predefined sequence.

3. The device according to claim 1 , wherein:
the imaging element is configured to move forward or backward over the defined distance along the optical axis of the first lens.

4. The device according to claim 3 , further comprising:
a translation stage, on which the imaging element is mounted and which is configured to move the imaging element forward and backward over the defined distance along the optical axis of the first lens.

5. The device according to claim 3 , wherein:
the imaging element is an image source.

6. The device according to claim 3 , wherein:
the imaging element is a mirror configured to reflect light from an image source into the first lens.

7. The device according to claim 6 , further comprising:
a second lens configured to reform an image from the image source as an intermediate image between the mirror and the first lens, wherein a distance between the intermediate image and the first lens is less than the fixed focal length of the first lens.

8. The device according to claim 6 , further comprising:
a polarizer arranged between the image source and the second lens to polarize the light from the image source,
a polarizing beam splitter, PBS, configured to reflect the polarized light from the image source onto the mirror.

9. The device according to claim 8 , further comprising:
a quarter waveplate arranged between the PBS and the mirror to allow light reflected from the mirror to pass through the PBS into the first lens.

10. The device according to claim 1 , further comprising:
a light guide arranged to redirect the light sent into and transmitted through the first lens so as to overlap said sent and transmitted light with ambient light.

11. The device according to claim 5 , wherein:
the imaging element is configured to move over the defined distance step by step with a step frequency that is equal to a refresh rate of the image source and with step lengths that correspond to a distance between two adjacent depth layers.

12. The device according to claim 5 , wherein:
the imaging element is configured to move forward and backward over the defined distance continually with a frequency that is equal to a frame rate of the image source.

13. The device according to claim 1 , further comprising:
an eye piece for displaying the generated 3D light field,
wherein a distance between the first lens and the eyepiece is equal to the fixed focal length of the first lens.

14. The device according to claim 1 , wherein the device is a head mount display, HMD, device.

15. A method for generating a 3-dimensional, 3D, light field, comprising:
sending light from an imaging element into a first lens having a fixed focal length, and
wherein the imaging element moves to different positions within a defined distance on an optical axis of the first lens, and sends the light from the different positions in order to produce different depth layers of the 3D light field within a frame duration.

16. The method according to claim 15 , comprising:
moving the imaging element forward and backward over the defined distance along the optical axis of the first lens, in order to send the light from the different positions.

17. The method according to claim 16 , comprising:
reflecting light from an image source into the first lens by a mirror, wherein an image from the image source is reformed as an intermediate image between the mirror and the first lens, and
moving the mirror forward and backward over the defined distance along the optical axis of the first lens, in order to move the intermediate image.

18. The device according to claim 5 , wherein the image source includes a display device.

Assignees

• Huawei Tech Co Ltd
• Cambridge Entpr Ltd

Inventors

• Jia Jia
• Chen Jhensi
• Chu Daping
• Zhang Qing
• Lin Tao

Classifications

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B30/25

  using polarisation techniques · CPC title

• G02B2027/0134

  of stereoscopic type · CPC title

• G02B30/52

  the three-dimensional [3D] volume being constructed from a stack or sequence of two-dimensional [2D] planes, e.g. depth sampling systems · CPC title

• G02B27/283 Primary

  used for beam splitting or combining · CPC title