Liquid crystal shutter having a specified zero voltage time viscosity product or a specified driving frequency

• US 5,699,133 A
• Filed: 05/29/1996
• Issued: 12/16/1997
• Est. Priority Date: 05/30/1995
• Status: Expired due to Fees

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Furuta, Yoshihiro
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): MALINOWSKI, WALTER J
• Application Number:
  US08/654,919
• Time in Patent Office: 566 Days
• Field of Search: 349/13, 349/15, 349/33, 349/179, 349/180
• US Class Current: 349/13
• CPC Class Codes: G02C 7/101 having an electro-optical light valve electro-optical elements per se G02F
• CPC Class Codes: G02F 1/1397 the twist being substantially higher than 90°, e.g. STN-, SBE-, OMI-LC cells
• CPC Class Codes: H04N 13/167 Synchronising or controlling image signals
• CPC Class Codes: H04N 13/189 Recording image signals; Reproducing recorded image signals
• CPC Class Codes: H04N 13/341 using temporal multiplexing
• CPC Class Codes: H04N 13/398 Synchronisation thereof; Control thereof

Abstract

A liquid crystal shutter has a liquid crystal layer which is made of a liquid crystal material prepared from a nematic liquid crystal. The ratio d/p of the thickness d of the liquid crystal layer to the chiral pitch p of the liquid crystal material and a twist angle θ which is set by a pair of alignment layers for liquid crystal molecules of the liquid crystal layer satisfy the relation of θ/360°<d/p.

Claims

1. A liquid crystal shutter comprising:

a pair of transparent substrates;

a pair of transparent electrodes being provided inside said pair of transparent substrates to be opposed to each other;

a liquid crystal layer being arranged between said pair of transparent electrodes; and

a pair of alignment layers being provided on both sides of said liquid crystal layer for aligning liquid crystal molecules of said liquid crystal layer,

a liquid crystal material forming said liquid crystal layer being prepared from a nematic liquid crystal, the ratio d/p of the thickness d of said liquid crystal layer to the chiral pitch p of said liquid crystal material and a twist angle θ

being set by said pair of alignment layers for said liquid crystal molecules of said liquid crystal layer satisfying the relation of θ

/360°

<

d/p, wherein said shutter alternates a voltage application period of applying a voltage exceeding the threshold voltage of said liquid crystal layer and a zero voltage period of not applying said voltage, and wherein a driving frequency f is in excess of a frequency satisfying f/(K33/K11)>

41.2 Hz in the range of 0.6≦

K33/K11≦

2.9.

2. The liquid crystal shutter in accordance with claim 1, wherein said liquid crystal molecules of said liquid crystal layer are substantially perpendicularly aligned at a twist angle of 0°

in said voltage application period, while being twisted at an angle exceeding said twist angle θ

in said zero voltage period.

3. The liquid crystal shutter in accordance with claim 1, wherein said twist angle θ

of said liquid crystal layer is about 270°

.

4. The liquid crystal shutter in accordance with claim 1, wherein said twist angle θ

of said liquid crystal layer is about 90°

.

5. The liquid crystal shutter in accordance with claim 1, being provided as each of right and left eye shutters of liquid crystal shutter glasses, said right and left eye shutters being driven to be alternately closed in a prescribed cycle.

6. A picture display observation system comprising:

the liquid crystal shutter glasses in accordance with claim 5; and

a picture display unit alternately displaying right and left eye pictures,

said liquid crystal shutter glasses being so driven as to close said right eye shutter in a period when said picture display unit displays a left eye picture while closing said left eye shutter in a period when said picture display unit displays a right eye picture.

7. The picture display observation system in accordance with claim 6, being a system for stereoscopically observing pictures.

8. A liquid crystal shutter comprising:

a pair of transparent substrates;

a pair of transparent electrodes being provided inside said pair of transparent substrates to be opposed to each other;

a liquid crystal layer being arranged between said pair of transparent electrodes; and

a pair of alignment layers being provided on both sides of said liquid crystal layer for aligning liquid crystal molecules of said liquid crystal layer,

a liquid crystal material forming said liquid crystal layer being prepared from a nematic liquid crystal, the ratio d/p of the thickness d of said liquid crystal layer to the chiral pitch p of said liquid crystal material and a twist angle θ

being set by said pair of alignment layers for said liquid crystal molecules of said liquid crystal layer satisfying the relation of θ

/360°

<

d/p, wherein said shutter alternates a voltage application period of applying a voltage exceeding the threshold voltage of said liquid crystal layer and a zero voltage period of not applying said voltage, and wherein a product t·

η

of the zero voltage period t and the viscosity η

is not more than 1.64×

10^-4 Pa·

sec.² in the range of 3≦

η

≦

35 mPa·

sec.

9. The liquid crystal shutter in accordance with claim 8, wherein said liquid crystal molecules of said liquid crystal layer are substantially perpendicularly aligned at a twist angle of 0°

in said voltage application period, while being twisted at an angle exceeding said twist angle θ

in said zero voltage period.

10. The liquid crystal shutter in accordance with claim 8, wherein said twist angle θ

of said liquid crystal layer is about 270°

.

11. The liquid crystal shutter in accordance with claim 8, wherein said twist angle θ

of said liquid crystal layer is about 90°

.

12. The liquid crystal shutter in accordance with claim 8, being provided as each of right and left eye shutters of liquid crystal shutter glasses, said right and left eye shutters being driven to be alternately closed in a prescribed cycle.

13. A picture display observation system comprising:

the liquid crystal shutter glasses in accordance with claim 12; and

a picture display unit alternately displaying right and left eye pictures,

said liquid crystal shutter glasses being so driven as to close said right eye shutter in a period when said picture display unit displays a left eye picture while closing said left eye shutter in a period when said picture display unit displays a right eye picture.

14. The picture display observation system in accordance with claim 13, being a system for stereoscopically observing pictures.