Liquid-crystal display device and method of signal transmission thereof

• US 6,784,861 B2
• Filed: 09/06/2002
• Issued: 08/31/2004
• Est. Priority Date: 09/06/2001
• Status: Expired due to Fees

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Okada, Kayo
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): NGUYEN, KIMNHUNG T
• Application Number:
  US10/236,280
• Publication Number:
  US 20030058213A1
• Time in Patent Office: 725 Days
• Field of Search: 345/87-100, 345/211-213, 345/209, 345/79, 345/54
• US Class Current: 345/87
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04

Abstract

A LCD device has a decreased number of required transmission lines. The first interface circuit, which is provided in the controller circuit, receives the polarization reverse signal and the horizontal scanning signal in parallel in such a way that the polarization reverse signal and the horizontal scanning signal have their active periods at different timings. The first interface circuit generates a serial signal from the polarization reverse signal and the horizontal scanning signal, and transmits the serial signal to the data electrode driver circuit by way of the transmission line or lines. The second interface circuit, which is provided in the data electrode driver circuit, regenerates the polarization reverse signal and the horizontal scanning signal in parallel from the serial signal.

Claims

1. A liquid-crystal display (LCD) device comprising:

a LCD panel having data electrodes for receiving pixel data signals, scanning electrodes for receiving scanning signals, and pixel regions located at intersections of the data electrodes and the scanning electrodes;

part of the pixel regions being chosen by the scanning signals;

the pixel data signals being applied to the part of the pixel regions, displaying images corresponding to the pixel data signals applied;

a data electrode driver circuit for receiving an image input signal to be synchronized with a horizontal scanning signal, for polarization-reversing the pixel data signals corresponding to the image input signal based on a polarization reverse signal, and for transmitting the pixel data signals thus polarization-reversed to the data electrodes of the panel;

a scanning electrode driver circuit for transmitting scanning signals to the scanning electrodes of the panel to be synchronized with a vertical scanning signal; and

a controller circuit for outputting the image input signal, the polarization reverse signal, the horizontal scanning signal, and the vertical scanning signal;

wherein the controller circuit comprises a first interface circuit for receiving the polarization reverse signal and the horizontal scanning signal in parallel in such a way that the polarization reverse signal and the horizontal scanning signal have their active mode periods at different timings, for generating a serial signal from the polarization reverse signal and the horizontal scanning signal, and for transmitting the serial signal to the data electrode driver circuit by way of a transmission line or lines;

and wherein the data electrode driver circuit comprises a second interface circuit for regenerating the polarization reverse signal and the horizontal scanning signal in parallel from the serial signal.

2. The device according to claim 1, wherein the device has a configuration that the serial signal is transmitted in a current mode.

3. The device according to claim 1, wherein the first interface circuit comprises a parallel-to-serial converter circuit for converting the polarization reverse signal and the horizontal scanning signal transmitted in parallel to a first serial signal voltage;

and a voltage-to-current converter circuit for converting the first serial signal voltage to a signal current;

the signal current being outputted to the transmission line or lines;

and wherein the second interface circuit comprises a current-to-voltage converter circuit for converting the signal current to a second signal voltage; and

a serial-to-parallel converter circuit for converting the second signal voltage to the polarization reverse signal and the horizontal scanning signal in parallel.

4. The device according to claim 1, wherein the data electrode driver circuit comprises at least one data electrode driver section according to a count of the data electrodes.

5. A method of transmitting signals in a liquid-crystal display (LCD) device;

the device comprising;

a LCD panel having data electrodes for receiving pixel data signals, scanning electrodes for receiving scanning signals, and pixel regions located at intersections of the data electrodes and the scanning electrodes;

part of the pixel regions being chosen by the scanning signals;

the pixel data signals being applied to the part of the pixel regions, displaying images corresponding to the pixel data signals applied;

a data electrode driver circuit for receiving an image input signal to be synchronized with a horizontal scanning signal, for polarization-reversing the pixel data signals corresponding to the image input signal based on a polarization reverse signal, and for transmitting the pixel data signals thus polarization-reversed to the data electrodes of the panel;

a scanning electrode driver circuit for transmitting scanning signals to the scanning electrodes of the panel to be synchronized with a vertical scanning signal; and

a controller circuit for outputting the image input signal, the polarization reverse signal, the horizontal scanning signal, and the vertical scanning signal;

the method comprising the steps of;

in the controller circuit, receiving the polarization reverse signal and the horizontal scanning signal in parallel in such a way that the polarization reverse signal and the horizontal scanning signal have their active mode periods at different timings;

generating a serial signal from the polarization reverse signal and the horizontal scanning signal; and

transmitting the serial signal to the data electrode driver circuit by way of a transmission line or lines; and

in the data electrode driver circuit, regenerating the polarization reverse signal and the horizontal scanning signal in parallel from the serial signal.

6. The method according to claim 5, wherein the serial signal is transmitted in a current mode.

7. The method according to claim 5, wherein the controller circuit conducts a parallel-to-serial conversion step for converting the polarization reverse signal and the horizontal scanning signal transmitted in parallel to a first serial signal voltage;

and a voltage-to-current conversion step for converting the first serial signal voltage to a signal current;

the signal current being outputted to the transmission line or lines;

and wherein the data electrode converter circuits conducts a current-to-voltage conversion step for converting the signal current to a second signal voltage; and

a serial-to-parallel conversion step for converting the second signal voltage to the polarization reverse signal and the horizontal scanning signal in parallel.