Apparatus with off-axis light path for characterizing the luminous intensity of lamp
US5818571A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 14, 1997 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Apr 14, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J1/4257
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus for determining the luminous intensity distribution of an automotive head light employs a curved mirror and a curved screen. A solid state camera is used to obtain a pattern of the head light output from the screen. The system requires a relatively small black box into which the head light output is directed. A beam splitter may be employed to relax the constraints on the positioning of the various components within the box. The setting of the test lamp to first and to second preset lateral angular positions at each of which a pattern is captured and the combining of the two patterns permits the use of components which are practical. The use of a linear CCD array permits economies to be obtained by rotating the test lamp or by scanning the linear array over a sequence of angular positions and by constructing a composite pattern from the patterns so generated. In an alternative embodiment, no beam splitter is used. Instead, the arrangement is an off axis arrangement which employs an aspheric lens at the input to the apparatus to reduce spot size at the screen and to improve the angular resolution measurement capability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.