Methods and Apparatus for Measurement of LC Cell Parameters
- Summary
- This invention is about three new measuring methods to determine the twist angle and retardation value of any twisted nematic liquid crystal cell. Twist angle of the liquid crystal alignment and the retardation value are important design parameters in determining the optical performance of liquid crystal displays (LCDs). Current measurement methods and commercially available equipment either requires prior knowledge of the twist angles, uses wave-plate compensation, or cannot determine some of the parameters. The new measuring methods make use of monochromatic light source such as laser beam. Values of the twist angle, retardation and twist sense can be obtained by data fitting using data obtained from adjusting only the polarizers and the LC cell orientations, It does not require prior knowledge of the LCD rubbing conditions and no retardation wave-plate is needed. There are three instrument configurations for the measuring method.
- Technology Benefits
- 1. Simple to implement
2. Do not need prior knowledge of LCD rubbing conditions
3. Do not need retardation wave-plate
4. Inspection can be conducted during and after manufacturing
- Technology Application
- - Liquid crystal displays (LCDs) in the quality control and inspection of liquid crystal cells during and after manufacturing
- Supplementary Information
- Patent Number: US6633358B1
Application Number: US2000712228A
Inventor: Kwok, Hoi Sing | Tang, Shu Tuen
Priority Date: 15 Nov 2000
Priority Number: US6633358B1
Application Date: 15 Nov 2000
Publication Date: 14 Oct 2003
IPC Current: G01N002121 | G01N002123 | G02F000113 | G02F00011335
US Class: 349136
Assignee Applicant: The Hong Kong University of Science & Technology
Title: Methods and apparatus for measurement of LC cell parameters
Usefulness: Methods and apparatus for measurement of LC cell parameters
Summary: For measuring parameters of liquid crystal unit.
Novelty: Method and device for measuring parameters of liquid crystal unit involves using single-color light source and regulating the directions of polarizer and LC unit
- Industry
- Optics
- Sub Category
- Laser
- Application Date
- 15 Nov 2000
- Application No.
- US 09/712228
- Patent Information
- US 6633358
- ID No.
- TTC.PA.204S
- Country/Region
- Hong Kong
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