Photoflash unit with two-color indicator
US4176389A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 1977 |
| Grant date | Nov 27, 1979 |
| Priority date | — |
| Expiry date | Oct 25, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B15/0457
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A photoflash unit having a flashed lamp indicator comprising two layers of film having different colors, one of the layers being a heat-shrinkable material and the other layer being translucent and substantially unaffected by the heat of lamp flashing. An adjacent indicia sheet provides an aperture through which one of the indicator colors is visible. Upon flashing of an associated lamp, the heat shrinkable layer shrivels from view and the color of the other layer becomes visible through the aperture to clearly identify which lamp was flashed. In one embodiment, the two-color indicator is used to identify the last lamp flashed in a sequence, while each of the preceding lamps in the sequence has a respectively associated single-layer color indicator which shrinks away to leave a void upon flashing of the lamp.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.