Optical modulator including liquid crystal, driving method thereof, and optical device using the same

Patent metadata

Field	Value
Publication number	US-10101629-B2
Application number	US-201514620110-A
Country	US
Kind code	B2
Filing date	Feb 11, 2015
Priority date	Aug 25, 2014
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

An optical modulation device or an optical device including the same includes: a first plate and a second plate facing the first plate; and a liquid crystal layer between the first plate and the second plate and including a plurality of liquid crystal molecules, wherein the first plate includes a plurality of first electrodes and a first aligner, the second plate includes at least one second electrode and a second aligner, and an alignment direction of the first aligner is substantially parallel to an alignment direction of the second aligner and wherein portions of the first plate, the second plate, and the liquid crystal layer between the first and second plates are individual units.

First claim

What is claimed is:

1. An optical modulation device comprising:
a first plate and a second plate facing the first plate; and
a liquid crystal layer between the first plate and the second plate and comprising a plurality of liquid crystal molecules, wherein
the first plate comprises a plurality of first electrodes and a first aligner, wherein
the second plate comprises at least one second electrode and a second aligner, where
portions of the first plate, the second plate, and the liquid crystal layer between the first and second plates are individual units, and wherein
when an electric field is applied to the liquid crystal layer, a first voltage supplied to one of the first electrodes in a first unit from among the units varies in a stepwise manner from a first step voltage during a period of a first step to a second step voltage during a period of a second step, a second voltage supplied to another of the first electrodes in the first unit varies in the stepwise manner increasing from a third step voltage during the same period of the first step to a fourth step voltage during the same period of the second step, the second step voltage being greater than the first step voltage, and the fourth step voltage is different from the second step voltage and is greater than the third step voltage;
which is different from the first step voltage.

2. The optical modulation device of claim 1 , wherein when no electric field is applied to the liquid crystal layer, a pre-tilt direction of the liquid crystal molecules adjacent to the first plate is opposite about a line normal to a surface of the first plate to a pre-tilt direction of the liquid crystal molecules adjacent to the second plate.

3. The optical modulation device of claim 2 , wherein when an electric field is applied to the liquid crystal layer, an intensity of the electric field in a region adjacent to the first electrode is greater than an intensity of the electric field in a region adjacent to the second electrode in the first unit.

4. The optical modulation device of claim 3 , wherein an intensity of the electric field in a region adjacent to the first plate is less than an intensity of the electric field in a region adjacent to the second plate in a second unit from among the units and neighboring the first unit.

5. The optical modulation device of claim 4 , wherein a respective one of the first electrodes is in each of the first unit and the second unit.

6. The optical modulation device of claim 5 , wherein the voltage supplied to the first electrode in the first unit is greater than a voltage supplied to the first electrode in the second unit.

7. The optical modulation device of claim 4 , wherein no first electrodes are in the second unit.

8. The optical modulation device of claim 4 , wherein the plurality of first electrodes comprises at least four first electrodes, and
wherein at least two of the first electrodes are in each of the first unit and the second unit.

9. The optical modulation device of claim 8 , wherein the voltage supplied to the first electrodes in the first unit is greater than a voltage supplied to the first electrodes in the second unit.

10. The optical modulation device of claim 4 , wherein the second plate further comprises a plurality of second electrodes.

11. The optical modulation device of claim 10 , wherein respective ones of the second electrodes are aligned with respective ones of the first electrodes.

12. The optical modulation device of claim 11 , wherein the second electrodes are arranged along a direction along which the first electrodes are arranged.

13. The optical modulation device of claim 10 , wherein the second electrodes are arranged along a direction which is substantially perpendicular to a direction along which the first electrodes are arranged.

14. The optical modulation device of claim 13 , wherein regions in which ones of the first electrodes overlap ones of the second electrodes and regions in which ones of the first electrodes do not overlap ones of the second electrodes are alternately arranged.

15. An optical device comprising the optical modulation device of claim 1 .

16. A method for driving an optical modulation device, the optical modulation device comprising a first plate and a second plate facing the first plate, the first plate comprising a plurality of first electrodes and the second plate comprises at least one second electrode, and a liquid crystal layer between the first plate and the second plate, wherein portions of the first plate, the second plate, and the liquid crystal layer between the first and second plates are individual units, the method comprising:
supplying a voltage to the first electrodes and to the at least one second electrode such that an intensity of an electric field in the liquid crystal layer in a region adjacent to the first plate and corresponding to one of the first electrodes in a first unit from among the units is greater than an intensity of the electric field in the liquid crystal layer in a region adjacent to the second plate, wherein
when an electric field is applied to the liquid crystal layer, a first voltage supplied to one of the first electrodes in the first unit varies in a stepwise manner increasing from a first step voltage during a period of a first step to a second step voltage during a period of a second step, a second voltage supplied to another of the first electrodes in the first unit varies in the stepwise manner increasing from a third step voltage during the same period of the first step to a fourth step voltage during the same period of the second step, the second step voltage being greater than the first step voltage, and the fourth step voltage is different from the second step voltage and is greater than the third step voltage, which is different from the first step voltage.

17. The method of claim 16 , wherein the supplying of the voltage to the first electrodes and the at least one second electrode creates an intensity of the electric field in the liquid crystal layer in a region adjacent to the first plate that is less than an intensity of the electric field in the liquid crystal layer in a region adjacent to the second plate and in a second unit from among the units and neighboring the first unit.

18. The method of claim 17 , wherein the voltage supplied to the first electrode in the first unit is greater than the voltage supplied to the first electrode in the second unit.

Assignees

• Samsung Display Co Ltd

Inventors

• Oh Soo Hee
• Park Yoon Kyung
• Jung Kyung Ho
• Jeong seung jun
• Baek Moon Jung
• Seo Hyun Seung

Classifications

• G02F1/1337

  Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers · CPC title

• G09G3/3696

  Generation of voltages supplied to electrode drivers · CPC title

• G02F1/292

  by controlled diffraction or phased-array beam steering (controlled diffraction for optical switching G02F1/31) · CPC title

• G02B5/1828 Primary

  having means for producing variable diffraction (controlling the direction of light by means of one or more diffracting elements G02B26/0808; acousto-optical elements G02F1/11, G02F1/33; electro- or magneto-optical diffraction G02F1/292, G02F1/2955) · CPC title

• G09G2300/0426

  Layout of electrodes and connections · CPC title