Thermochromic drawing device
US5441418A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1993 |
| Grant date | Aug 15, 1995 |
| Priority date | — |
| Expiry date | May 20, 2013 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41M5/282
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A thermochromic drawing device is disclosed which can be marked and erased by selectively changing the temperature of its drawing surface. The drawing surface of the drawing device consists of a flexible substrate printed with thermochromic inks having at least two color states. The flexible substrate has low thermal mass thereby enabling it to readily assimilate temperatures induced by a user and, consequently, facilitating the transition of the thermochromic inks from one color state to another. The drawing surface is further provided with an insulating layer which isolates the flexible substrate from unwanted heat sinks and heat sources thereby preventing unwanted color transitions of the thermochromic inks. Thus, a user can selectively change the color state of portions of the drawing surface to create distinctive markings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.