Liquid crystal display device having a digitizer

• US 6,661,399 B1
• Filed: 06/21/2000
• Issued: 12/09/2003
• Est. Priority Date: 06/21/1999
• Status: Expired due to Term

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Ahn, Young-Soo, Jeong, Yun-Cheol, Oh, Young-Jin
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US09/598,606
• Time in Patent Office: 1,266 Days
• Field of Search: 345/173, 345/905, 345/87, 345/174, 345/175, 345/176, 345/177, 178/18.01, 178/18.11, 178/21.01, 178/18.03, 178/18.04, 178/18.05, 178/18.06, 178/18.07
• US Class Current: 345/87
• CPC Class Codes: G02F 1/133334 Electromagnetic shields
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 1/1601 Constructional details related to the housing of computer displays, e.g. of CRT monitors, of flat displays constructional details related to flat displays integrated in a portable computer, e.g. laptop, handheld computer G06F1/1637; constructional details related to television receivers H04N5/64
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: G06F 3/147 using display panels

Abstract

A liquid crystal display (LCD) device having a digitizer. A liquid crystal panel is supported by a lower frame having a side wall portion. A digitizer is located on the liquid crystal panel. An upper frame having a front surface with an opening region and a side wall portion is located over the digitizer such that the tipper frame pressurizes a peripheral portion of the digitizer. The opening region is formed at a location corresponding to the display region of the liquid crystal panel. The upper and lower frames mate to hold the liquid crystal panel and the digitizer in place. The upper frame is beneficially metallic to provide electrical shielding of conductors on the digitizer. Common electrical circuits are shared by the digitizer and the liquid crystal panel.

Claims

1. A liquid crystal display, comprising:

a first frame;

a liquid crystal panel supported by said first frame, said liquid crystal panel having a display region and a side portion;

a digitizer on said liquid crystal panel, said digitizer having a peripheral portion and a plurality of digitizer electrodes;

a second frame having a side wall and a front surface with an opening, said front surface pressing against said peripheral portion of said digitizer, said opening formed at a location corresponding to said display region of said liquid crystal panel;

a printed circuit board having a drive circuit, said drive circuit driving said digitizer; and

a plurality of electric connections for connecting said drive circuit to said corresponding digitizer electrodes, said electric connections having the same length,

wherein said second frame and said first frame are secured together so as to hold said liquid crystal panel and said digitizer.

2. A liquid crystal display according to claim 1, wherein said electric connections pass between the side wall portion of the liquid crystal panel and the side wall portion of the second frame.

3. A liquid crystal display according to claim 2, wherein said plurality of digitizer electrodes are covered by said front surface.

4. A liquid crystal display according to claim 3, wherein said second frame is conductive.

5. A liquid crystal display according to claims 1, further comprising a controlling circuit on said printed circuit boards for controlling both said liquid crystal panel and said digitizer.

6. A liquid crystal display according to claim 1, wherein said printed circuit board are provided on a back surface of said first frame.

7. A liquid crystal display according to claim 1, wherein said drive circuit includes a power supply for supplying electrical power to said digitizer and to said liquid crystal panel.

8. A liquid crystal display according to claim 1, wherein said printed circuit board is mounted on said first frame.

9. A liquid crystal display according to claim 1, wherein said second frame and said first frame are secured together via screws.

10. A liquid crystal display according to claim 1, wherein said second frame and said first frame are secured together via bendable portions that mate with recesses.

11. A liquid crystal display according to claim 1, wherein said digitizer is a resistive digitizer.

12. A liquid crystal display according to claim 1, wherein said digitizer is a coupling capacitive type digitizer.

13. A liquid crystal display device, comprising:

a digitizer having a plurality of digitizer electrodes for producing location signals indicative of a location of an external input on a digitizer pattern;

a liquid crystal panel for displaying information according to signals produced by said digitizer;

a printed circuit board having a drive circuit, said drive circuit driving said digitizer; and

a plurality of electric connections for connecting said drive circuit to said corresponding digitizer electrodes, said electric connections having the same length,

wherein said drive circuit includes a controller for controlling both said digitizer and said crystal panel according to a clock generator.

14. A liquid crystal display device according to claim 13, wherein said drive circuit further includes a power supply for supplying a voltage to said liquid crystal panel and to said digitizer.

15. A liquid crystal display device according to claim 13, wherein said digitizer produces analog signals, and wherein said drive circuit includes an analog to digital (A/D) converter for converting said analog signals to digital signals.

16. A liquid crystal display device according to claim 15, wherein said drive circuit further includes a first input/output (I/O) unit for conveying analog signals to said A/D converter and for conveying signals from said controller to said digitizer.

17. The liquid crystal display device of claim 16, wherein said first I/O unit is a serial port.

18. A liquid crystal display device according to claim 16, wherein said drive circuit further includes a second input/output (I/0) unit for transferring digital signals in the form of x-y coordinate values from said A/D converter to a main system.

19. A liquid crystal display device according to claim 13, said drive circuit further includes a gamma circuit for correcting gamma characteristics of said liquid crystal panel.

20. A liquid crystal display device according to claim 13, wherein said drive circuit further includes a data driver and a gate driver that are both driven by said clock generator.

21. A liquid crystal display device according to claim 13, further including a first frame and a second frame for securing said liquid crystal panel and said digitizer.

22. A liquid crystal display device according to claim 21, wherein said second frame includes a front surface pressing said digitizer toward said liquid crystal panel.