Transflective liquid crystal display device having first and second switching devices connecting a same data line and two different gate lines in each pixel

• US 8,436,967 B2
• Filed: 03/16/2010
• Issued: 05/07/2013
• Est. Priority Date: 06/30/2005
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd.
• Original Assignee: NLT Technologies, Ltd.
• Inventors: Sakamoto, Michiaki, Matsushima, Jin, Nagai, Hiroshi, Mori, Kenichi, Ikeno, Hidenori, Kudo, Yasuki, Sumiyoshi, Ken
• Primary Examiner(s): NGO, HUYEN LE
• Application Number:
  US12/725,339
• Publication Number:
  US 20100171775A1
• Time in Patent Office: 1,148 Days
• Field of Search: 349/114, 349/141, 349/96, 349/103
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0456 with a reflective area and a transmissive area combined in one pixel, such as in transflectance pixels
• CPC Class Codes: G09G 2320/028 by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
• CPC Class Codes: G09G 3/3659 the addressing of the pixel involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependant on signal of two data electrodes

Abstract

An IPS-mode transflective LCD device includes an array of pixels each including a reflective region and a transmissive region juxtaposed. The reflective region operates in a normally-white mode, and the transmissive region operates in a normally-black mode. A common data signal is supplied to the reflective region and transmissive region, whereas the common electrode signal in the transmissive region is an inverted signal of the common electrode signal in the reflective region, to thereby obtain similar gray-scale levels.

Claims

1. A transflective liquid crystal display (LCD) device comprising a liquid crystal (LC) layer defining an array of pixels arranged in a matrix, each of said pixels including therein a reflective region and a transmissive region juxtaposed, wherein:

each of said pixels includes a first pixel electrode in said reflective region, and a second pixel electrode in said transmissive region; and

each of said pixels is associated with a first switching device for coupling together said first electrode to and a data line supplying a data signal, and a second switching device for coupling together said second electrode and said data line, further comprising a first gate line for controlling said first switching devices and a second gate line for controlling said second switching devices, wherein said first and second switching devices are connected to said data line in common.

2. The LCD device according to claim 1, further comprising a data converter for converting a first gray-scale level of a data signal received from outside of said LCD device into a second gray-scale level to be supplied to one of said first pixel electrode and said second pixel electrode.

3. The LCD device according to claim 2, wherein said data converter includes a memory for storing therein said data signal received from outside, and a gray-scale level converter for converting said first gray-scale level of said data signal into said second gray-scale level, and writes said second and first gray-scale levels into said one and the other, respectively, of said first pixel electrode and said second pixel electrode.

4. The LCD device according to claim 3, wherein said gray-scale level converter is configured by a logic circuit.

5. The LCD device according to claim 3, wherein said gray-scale level converter converts said first gray-scale level into said second gray-scale level by using a look-up table.

6. The LCD device according to claim 5, wherein said look-up table tabulates said first gray-scale level and corresponding second gray-scale level in association so that said first gray scale level assumes a maximum when said corresponding second gray-scale level assumes a minimum.

7. The LCD device according to claim 1, further comprising a single common electrode including a plurality of common electrodes disposed in said reflective regions and said transmissive regions of a plurality of said pixels.

8. The LCD device according to claim 7, wherein a potential to be written in said single common electrode is inverted at a timing of switching for writing data through said first switching device or said second switching device.