Liquid crystal grating, manufacturing method and drive method thereof, and optical phased array device

Patent metadata

Field	Value
Publication number	US-9785016-B2
Application number	US-201314369441-A
Country	US
Kind code	B2
Filing date	Dec 19, 2013
Priority date	Aug 6, 2013
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

The present invention discloses a liquid crystal grating, a manufacturing method and a drive method thereof, and an optical phased array. In the liquid crystal grating, plurality of first electrodes are formed on a lower substrate with first gaps formed between adjacent first electrodes, second electrodes are further provided above the first gaps with second gaps formed between adjacent second electrodes, and an insulation layer is provided between the first electrodes and the second electrodes. When voltages are applied to the first electrodes and the second electrodes, continuously and smoothly changing electric field is generated inside the liquid crystal grating, and then phases of incident light may be controlled continuously and smoothly, which improves the ability of the liquid crystal grating to modulate light beam.

First claim

The invention claimed is:

1. A liquid crystal grating, comprising: an upper substrate and a lower substrate provided opposite to each other, liquid crystal filled between the upper substrate and the lower substrate, and a common electrode formed on the upper substrate, wherein, a plurality of first electrodes are formed on the lower substrate with first gaps formed between adjacent first electrodes, second electrodes are formed above the first gaps with second gaps formed between adjacent second electrodes, only an insulation layer is provided between the first electrodes and the second electrodes, the first electrodes and the second electrodes are insulated from each other without electric connection therebetween, widths of the second electrodes are larger than those of the first electrodes, and the first electrodes and the common electrode are electrically insulated from each other.

2. The liquid crystal grating of claim 1 , wherein the first electrodes and the second electrodes have a bar-like shape.

3. The liquid crystal grating of claim 2 , wherein projections of center lines of the second gaps on the lower substrate coincide with projections of center lines of the first electrodes on the lower substrate.

4. The liquid crystal grating of claim 1 , wherein the widths of the first electrodes are larger than or equal to those of the second gaps.

5. The liquid crystal grating of claim 1 , wherein a drive chip connected to the first electrodes and the second electrodes is further provided on the lower substrate.

6. The liquid crystal grating of claim 5 , wherein the drive chip comprises: a first drive sub-chip and a second drive sub-chip, one of which is connected to the first electrodes, and the other of which is connected to the second electrodes.

7. A manufacturing method of a liquid crystal grating, comprising the steps of:
forming a common electrode on an upper substrate;
forming first electrodes on a lower substrate, such that first gaps are formed between adjacent first electrodes;
forming only an insulation layer on the lower substrate formed with the first electrodes;
forming second electrodes above the first gaps on the lower substrate formed with the insulation layer, such that second gaps are formed between adjacent second electrodes, the first electrodes and the second electrodes are insulated from each other without electric connection therebetween, widths of the second electrodes are larger than those of the first electrodes, and the first electrodes and the common electrode are electrically insulated from each other; and
aligning the upper substrate with the lower substrate to form a cell, and filling liquid crystal between the upper substrate and the lower substrate.

8. An optical phased array device comprising a liquid crystal grating, wherein the liquid crystal grating comprises: an upper substrate and a lower substrate provided opposite to each other, liquid crystal filled between the upper substrate and the lower substrate, and a common electrode formed on the upper substrate, wherein, a plurality of first electrodes are formed on the lower substrate with first gaps formed between adjacent first electrodes, second electrodes are formed above the first gaps with second gaps formed between adjacent second electrodes, only an insulation layer is provided between the first electrodes and the second electrodes, the first electrodes and the second electrodes are insulated from each other without electric connection therebetween, widths of the second electrodes are larger than those of the first electrodes, and the first electrodes and the common electrode are electrically insulated from each other.

9. The optical phased array device of claim 8 , wherein the first electrodes and the second electrodes have a bar-like shape.

10. The optical phased array device of claim 9 , wherein projections of center lines of the second gaps on the lower substrate coincide with projections of center lines of the first electrodes on the lower substrate.

11. The optical phased array device of claim 8 , wherein a drive chip connected to the first electrodes and the second electrodes is further provided on the lower substrate.

12. The optical phased array device of claim 11 , wherein the drive chip comprises: a first drive sub-chip and a second drive sub-chip, one of which is connected to the first electrodes, and the other of which is connected to the second electrodes.

13. A drive method of the liquid crystal grating of claim 1 , comprising:
applying voltages to the first electrodes and the second electrodes of the liquid crystal grating, respectively, so that first electric fields are formed between the first electrodes and the common electrode and second electric fields are formed between the second electrodes and the common electrode, so as to jointly drive the liquid crystal of the liquid crystal grating to rotate.

14. The drive method of claim 13 , wherein a voltage U 3 ′ applied to the first electrode is:

U
3
′

=

(

1
+

ɛ
LC

⁢

d
p

ɛ
p

⁢

d
LC

)

⁢

U
3

wherein, U 3 is a theoretical voltage on the upper surface of the insulation layer, ∈ LC is a relative dielectric constant of the liquid crystal under the action of the voltage U 3 , d LC is a thickness of the liquid crystal cell, ∈ p is a relative dielectric constant of the insulation layer, and d p is a thickness of the insulation layer.

Assignees

• Boe Technology Group Co Ltd

Inventors

• Shi Shiming
• Shi Ling
• Sun Tao
• Li Yunfei

Classifications

• Y10T29/49124

  On flat or curved insulated base, e.g., printed circuit, etc. · CPC title

• G02F1/134309 Primary

  characterised by their geometrical arrangement · CPC title

• G02F2201/305

  diffraction grating · CPC title