Optically reflecting code plate
US4661697A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 15, 1985 |
| Grant date | Apr 28, 1987 |
| Priority date | — |
| Expiry date | Apr 15, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/34707
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Herein disclosed is an optically reflecting code plate having a number of reflective and unreflective portions formed alternately on the surface of its substrate. This substrate is made of aluminum of high purity, for example, and has its surface anodized with a colorless, transparent and porous aluminum oxide film. At predetermined positions of the oxide film, which are to be formed with the aforementioned unreflective portions, moreover, metal such as nickel, tin, copper, iron, cobalt, silver, manganese or selenium is deposited by electrodeposition in the bottoms of the pores of the oxide film thereby to form a metal-deposited layer. Moreover, the vicinities of the openings of the aforementioned pores are impregnated with a dye such as a black metallized complex salt dye or a Nigrosine dye to form a dye-impregnated layer. The aforementioned metal-deposited layer and the dye-impregnated layer are overlaid the later over the former thereby to form the unreflective portions. The remaining portion shaving neither the metal-deposited layer nor the dye-impregnated layer so that it is exposed directly to the outside is left as the reflective portions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.