Liquid crystal cell and photographic system

Patent metadata

Field	Value
Publication number	US-10627667-B2
Application number	US-201816028147-A
Country	US
Kind code	B2
Filing date	Jul 5, 2018
Priority date	Nov 23, 2017
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

A liquid crystal cell and a photographic system are described. The liquid crystal cell includes: a refractive index switching layer including a liquid crystal layer consisting of liquid crystals and a substrate on which a plurality of diffractive lenses are formed; a first transparent electrode layer; and a second transparent electrode layer. The liquid crystal layer has a first refractive index and a second refractive index when the first transparent electrode layer and the second transparent electrode layer are powered on and off, respectively. The first refractive index is greater than the second refractive index, and the first refractive index is the same as the refractive index of the diffractive lenses. By means of this solution, free and controllable switching between light field imaging and conventional photographic imaging can be realized in the same system.

First claim

The invention claimed is:

1. A liquid crystal cell, comprising:
a refractive index switching layer, wherein the refractive index switching layer comprises:
a liquid crystal layer consisting of liquid crystals, and
a substrate on which a plurality of diffractive lenses are formed;

a first transparent electrode layer; and
a second transparent electrode layer;
a polarizer arranged on a side of the refractive index switching layer selected from a group consisting of a side of the refractive index switching layer close to the diffractive lenses and a side of the refractive index switching layer far from the diffractive lenses;
wherein, the liquid crystal layer has a first refractive index under the condition that the first transparent electrode layer and the second transparent electrode layer are powered on, and the liquid crystal layer has a second refractive index under the condition that the first transparent electrode layer and the second transparent electrode layer are powered off; and
wherein the first refractive index is greater than the second refractive index, and the first refractive index is the same as a refractive index of the diffractive lenses.

2. The liquid crystal cell according to claim 1 , wherein a plurality of concentric circular diffractive phase grating strips are arranged on a side of each of the plurality of diffractive lenses facing the liquid crystal layer, wherein a gap between two adjacent circular diffractive phase grating strips is a grating groove, and wherein the liquid crystals at least fill the grating groove.

3. The liquid crystal cell according to claim 2 , wherein the first transparent electrode layer and the second transparent electrode layer are located at a same side of the refractive index switching layer.

4. The liquid crystal cell according to claim 2 , wherein the first transparent electrode layer and the second transparent electrode layer are located at different sides of the refractive index switching layer.

5. The liquid crystal cell according to claim 3 , wherein one of the first transparent electrode layer and the second transparent electrode layer is a strip electrode layer comprising parallel strip electrodes, and the other of the first transparent electrode layer and the second transparent electrode layer is a planar electrode layer.

6. The liquid crystal cell according to claim 4 , wherein one of the first transparent electrode layer and the second transparent electrode layer is a strip electrode layer comprising parallel strip electrodes, and the other of the first transparent electrode layer and the second transparent electrode layer is a planar electrode layer.

7. The liquid crystal cell according to claim 2 , wherein parameters of the circular diffractive phase grating strip satisfy the following equations:

N
=

2
m

;

ϕ
=

2
⁢

⁢
π

N

;

h
=

λ
N

n
-

n
0

;

d
j

=

r
j

-

r

j
-
1

;

r
j

=

jf
⁢

⁢
λ

;

t
j

=

{

d
j

N
2

,

(

j
⁢

⁢
is
⁢

⁢
an
⁢

⁢
even
⁢

⁢
number

)

d
j

-

∑

i
=
1

m
-
1

⁢

d

j
+
1

Assignees

• Boe Technology Group Co Ltd

Inventors

• Gao Jian
• Chen Xiaochuan
• Yang Yafeng
• Tan Jifeng

Classifications

• G02F1/29 Primary

  for the control of the position or the direction of light beams, i.e. deflection · CPC title

• G02F2203/22

  diffractive · CPC title

• G02F1/13471

  in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells (G02F1/13475 takes precedence) · CPC title

• G02B5/1809

  with pitch less than or comparable to the wavelength · CPC title

• G02F1/1313 Primary

  specially adapted for a particular application · CPC title