Miss convergence compensating device for projection type display
US4961030A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 1989 |
| Grant date | Oct 2, 1990 |
| Priority date | — |
| Expiry date | May 18, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/31
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a miss convergence compensating circuit of a projection type display. The projection type display is provided with three projection tubes for red, green and blue colors and a color image is obtained by combining three colors from three projection tubes on a screen. When such projection tubes are arranged slant to the screen, miss convergence is generated on the screen. A convergence yoke for auxiliary deflection of electron beam is generally provided in order to compensate for such miss convergence, but this convergence yoke has the deflection sensitivity which is worse than that of deflection yoke. Therefore, the present invention contributes to compensate for miss convergence using the deflection yokes. For this purpose, at least two deflection coils are provided with a transformer coupling which allow the compensating currents corresponding to the miss convergence compensating signals to flow. In this case, the transformer coupling is coupled so that the currents of opposite polarities are caused to flow into at least two deflection coils as the compensating currents.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.