Digital thermometer and method of manufacture
US3965742A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 24, 1974 |
| Grant date | Jun 29, 1976 |
| Priority date | — |
| Expiry date | Oct 24, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K11/165
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A non-breakable digital thermometer and a method for its manufacture are provided. The thermometer comprises a plastic strip, either flexible or rigid, of microencapsulated temperature responsive liquid crystal material in a lateral array of numerical indicia, each index having associated with it liquid crystals having a temperature responsive range relevant to the numerical value of the index. Overlap of temperature responsive ranges is provided to insure at least one visible indicia, when the temperature being measured is within the range of interest. A substantially continuous sheet of an inert transparent base is sequentially printed with a darkly pigmented mask defining transparent indicia areas. Different liquid crystal composition slurries are coated in a continuous stripe over the appropriate indicia, with adjacent compositions allowed to mix at the edges, before rapid partial drying prevents additional mixing. The compositions are then dried substantially completely, and coated with a darkly pigmented coating. Individual strips are then cut transverse to the direction of movement of the film so as to provide individual digital thermometers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.