Reflector for vehicle headlight
US5192124A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1991 |
| Grant date | Mar 9, 1993 |
| Priority date | — |
| Expiry date | Oct 29, 2011 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF21S41/32
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An elliptical paraboloid, which is a basic surface, has an elliptical section when it is cut by a plane perpendicular to its optical axis, and has a parabolic section when it is cut by a plane including its optical axis. A light source is arranged on the optical axis. A cross sectional curve obtained when a reflecting surface is cut by a plane perpendicular to its optical axis is expressed by a finite-order vector algebraic expression by specifying its end point positions and coefficient vectors. As a result, the reflecting surface is formed as a free surface deviating from the basic surface. Operations for controlling the surface, which are important in forming a cutline, are an operation of making the tangential vector at the end point of the cross sectional curve orthogonal to the position vector, and an operation of twisting the surface. By these operations the light-distribution control is performed so that longitudinally extending peripheries of respective filament images can be flush with one another. Finally, a sharp cutline is formed which is specific to a low beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.