Liquid crystal display device with display holding device

• US 5,070,409 A
• Filed: 06/12/1990
• Issued: 12/03/1991
• Est. Priority Date: 06/13/1989
• Status: Expired due to Term

• Current Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Original Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Inventors: Aoki, Harumi, Miyadera, Shunichi
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Murrell, Jeffrey S.
• Application Number:
  US07/536,779
• Time in Patent Office: 539 Days
• Field of Search: 358/236, 358/241, 358/212, 350/500
• US Class Current: 348/790
• CPC Class Codes: G09F 9/35 being liquid crystals G09F9/302 takes precedence; liquid crystal materials C09K19/00; liquid crystal panels comprising a number of electrodes in a single cell per se G02F1/13
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: H04N 1/0044 for image preview or review, e.g. to help the user position a sheet
• CPC Class Codes: H04N 1/2112 using still video cameras
• CPC Class Codes: H04N 2101/00 Still video cameras

Abstract

A liquid crystal display device is provided for receiving a video signal and displaying a visual image. The display device employs an active matrix liquid crystal display member having a plurality of display elements, and a plurality of switching elements, respectively. An image signal included in the video signal is applied to the display elements in accordance with a horizontal synchronous signal. The signal corresponding to the synchronous signal included in the video signal to be applied to the switching elements is inhibited for a predetermined period of time so that the image is kept displayed by the display elements for a certain period of time without the need to supply another video signal.

Claims

1. A liquid crystal display device for receiving video signal and displaying a visual image, comprising:

an active matrix liquid crystal display member having a plurality of display elements and a plurality of switching elements;

means for supplying, based upon said video signal, a drive signal to said display elements through respective ones of said switching elements;

control means for keeping said switching elements in an OFF condition for a predetermined period of time so that the supply of said drive signal to said display elements is interrupted, whereby a still image is displayed for said predetermined period of time without the need to apply another video signal to said display member.

2. The liquid crystal display device according to claim 1, wherein said video signal comprises an image signal, a horizontal synchronous signal, and a vertical synchronous signal, and wherein said drive signal supplying means comprises:

first driving means for supplying said drive signal to said display elements through respective ones of said switching elements according to said image signal and said vertical synchronous signal included in said video signal; and

second driving means for supplying a switching signal to respective ones of said switching elements according to said horizontal synchronous signal included in said video signal, where said control means comprises means for inhibiting said second driving means form supplying said switching signals, and wherein said control means drives said inhibiting means for said predetermined period of time.

3. The liquid crystal display device according to claim 1, wherein the display member comprises a plurality of capacitive means connected to respective ones of said display elements for holding a charge applied to respective ones of said display elements for said predetermined period of time.

4. The liquid crystal displaying device according to claim 1, wherein said display elements are capable of holding charges to maintain said image to be displayed for at least said predetermined period of time.

5. A video signal processing device, comprising:

means for photographing an object and converting an image of said object into a video signal, said video signal comprising an image signal, a horizontal synchronous signal, and a vertical synchronous signal;

an active matrix liquid crystal display member having a plurality of display elements and a plurality of switching elements;

means for supplying, based upon said video signal, a drive signal to said display elements though respective ones of said switching elements;

control means for keeping said switching elements in an OFF condition for a predetermined period of time so that the supply of said drive signal to said display elements is interrupted, whereby a visual still image is displayed for said predetermined period of time without the need to apply another video signal to said display member.

6. The liquid crystal displaying device according to claim 5, wherein said drive signal supplying means comprises:

first driving means for supplying said drive signal to said display elements through respective ones of said switching elements according to said image signal and said vertical synchronous signal included in said video signal; and

second driving means for supplying a switching signal to respective ones of said switching elements according to said horizontal synchronous signal included in said video signal, wherein said control means comprise means for inhibiting said second driving means from supplying said switching signal, and wherein said control means drives said inhibiting means for said predetermined period of time.

7. The video signal processing device according to claim 6, further comprising means for recording said video signal on a recording medium.

8. The video signal processing device according to claim 7, further comprising means for regenerating said video signal that has been recorded on said recording medium.

9. The video signal processing device according to claim 7, wherein said recording means comprises switch means for starting said recording of said video signal, and wherein said control means drives said inhibiting means when said switch means is operated.

10. The liquid crystal display device according to claim 5, wherein said display member comprises a plurality of capacitive means connected to respective ones of said display elements for holding a charge applied to respective ones of said display elements for said predetermined period of time.

11. The video signal processing device according to claim 10, wherein said capacitive means are capable of holding charges to maintain the image to be displayed on said display member for at least said predetermined period of time.

12. The video signal processing device according to claim 5, wherein said display member is capable of holding charges to maintain the image to be displayed on said display member for at least one predetermined period of time.