Image quality inspection system
US5696550A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 1995 |
| Grant date | Dec 9, 1997 |
| Priority date | — |
| Expiry date | Jul 14, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/136263
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image quality inspection system determines view angle dependent defects by capturing an LCD image viewed obliquely over the entire LCD panel while in focus. The system obtains the positions of each of the LCD pixels from the distorted screen as a CCD pixel address and captures the CCD image precisely. In a first embodiment, a second CCD camera has a built-in CCD area sensor and measures the contrast of the LCD obliquely. The second CCD camera has a built-in tilt lens system or a built-in shift lens systems which allows it to focus on the entire LCD panel plane. In order to convert the distorted image on the CCD pixels to a normal LCD image, an LCD driver section generates a calibration pattern, an image measuring section converts the measured values of the CCD pixels to digital signals, a CCD address setting for the LCD pixels seeks sampling addresses of the entire LCD pixels as real numbers, and a presampling processor uses interpolation to convert the digital signals to an image having the number of pixels of the LCD panel. In a second embodiment, an image element, such as a CCD, is mobile in parallel with the lens plane in all directions. A lens is mobile vertically with resp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.