Liquid crystal display panel capable of reducing persistence degree and development method thereof

• US 20070008476A1
• Filed: 09/15/2006
• Published: 01/11/2007
• Est. Priority Date: 10/31/2000
• Status: Active Grant

• Current Assignee: Hidefumi Yoshida, Hidetoshi Sukenori, Takashi Sasabayashi, Tetsuya Fujikawa, Yasutoshi Tasaka, Yohei Nakanishi
• Original Assignee: Hidefumi Yoshida, Hidetoshi Sukenori, Takashi Sasabayashi, Tetsuya Fujikawa, Yasutoshi Tasaka, Yohei Nakanishi
• Inventors: Fujikawa, Tetsuya, Sasabayashi, Takashi, Tasaka, Yasutoshi, Nakanishi, Yohei, Yoshida, Hidefumi, Sukenori, Hidetoshi
• Granted Patent: US 7,397,454 B2
• Time in Patent Office: Days
• US Class Current: 349/143
• 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 2300/0439 Pixel structures
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0257 Reduction of after-image effects
• 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 2320/046 Dealing with screen burn-in prevention or compensation of the effects thereof
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

AC voltage of rectangular wave is applied between a pixel electrode 25A and a common electrode 23A, and the amplitude Vac of the AC voltage component and the DC voltage component Vdc thereof are changed to measure the range of optimal DC component variation ΔVdc and determine a structure or material of a liquid crystal display device so as to lower ΔVdc less than a given value, wherein ΔVdc=|Vdcb−Vdcw|, Vdcb is the value of Vdc at which the range of transmittance variation is the minimum with Vac being fixed at a value for displaying black (2V), and Vdcw is the value of Vdc at which the range of transmittance variation is the minimum with Vac being fixed at a value for displaying white (7 V). Thickness of an insulating layer 26A on the pixel electrode 25A and on the common electrode 23A are the same. Electrode crossover portions are made to be in axial symmetry. The top surface of each stripe electrode of a pixel electrode has convex shape in cross section.

Claims

1. A liquid crystal panel development method, said liquid crystal panel comprising:

first and second substrate, said first substrate including a first electrode, said first or second substrate including a second electrode, said first and second electrode being for a display voltage to be applied therebetween; and

liquid crystal interposed between said first and second substrates;

said method comprising the steps of;

applying a voltage signal between said first electrode and said second electrode, said voltage signal being composed of an AC voltage component and a DC voltage component Vdc, said AC voltage component having an amplitude Vac;

changing said amplitude Vac and said DC voltage component Vdc to measure the range of optimal DC component variation Δ

Vdc; and

determining a structure or material of said liquid crystal panel such that said range of optimal DC component variation Δ

Vdc becomes less than a given value;

wherein said range of optimal DC component variation Δ

Vdc is defined as Δ

Vdc=|Vdcb−

Vdcw|,

wherein Vdcb is a value of said DC voltage component Vdc at which a range of transmittance variation is the minimum when said DC voltage component Vdc is changed with said amplitude Vac being fixed at a value for displaying black,

wherein Vdcw is a value of said DC voltage component Vdc at which a range of transmittance variation is the minimum when said DC voltage component Vdc is changed with said amplitude Vac being fixed at a value for displaying white.

2. The liquid crystal panel development method of claim 1, wherein said given value is equal to or less than 0.5 V.