Lighting device
US4388676A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 1980 |
| Grant date | Jun 14, 1983 |
| Priority date | — |
| Expiry date | Dec 4, 2000 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF21Y2103/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A straight cylindrical light source formed of, for example, a fluorescent lamp is set in place at a predetermined distance from a desk top surface. A reflector whose cross section is shaped substantially like a parabola is positioned at the back of the light source. A housing having an opening formed at least on the underside is provided to enclose the light source and reflector. Where a vertical angle defined by a straight line l.sub.0 connecting the axis of the light source to the front edge of the desk top surface defines .theta..sub.0, then a vertical angle .theta..sub.1 defined by a straight line l.sub.1 tangentially contacting the upper peripheral surface of the cylindrical light source and extending to the front end of the lower opening of the housing is also prescribed to be substantially .theta..sub.0. A vertical angle .theta..sub.2 defined by a straight line l.sub.2 passing through the upper terminal end of the reflector and tangentially contacting the lower peripheral surface of the cylindrical light source is also chosen to be substantially .theta..sub.0. The reflector is so positioned that the focal point of its parabolic cross section is substantially aligned with the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.