Multiple color writing tablet
US8228301B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 16, 2008 |
| Grant date | Jul 24, 2012 |
| Priority date | — |
| Expiry date | Feb 21, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0412
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
One aspect of the invention is a bistable cholesteric writing tablet on which an image is formed by applying a suitable voltage while applying writing pressure, which results in a focal conic texture in a reduced gap region of the active layer while not changing the texture of the unreduced gap region of the active layer (e.g., a written portion being in a focal conic texture on a background in the planar texture). Another aspect of the invention is a multi-color stacked writing tablet in which a color of an image is selected by applying a suitable voltage while applying writing pressure using an instrument such as an untethered stylus on the surface of the tablet. The writing tablet includes at least two or three stacked layers of bistable cholesteric liquid crystal material. Selected colors can be additively mixed to achieve intermediate colors as desired. The image can be erased and new images written on the tablet. Gray scale achieved by varying the applied voltage during writing or the writing pressure in some cases, enables the writing tablet to produce a broad range of colors. The writing device is suitable for many applications such as a toy, sketch pad, erasable signage, t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.