# US 5,707,141 A · Vehicle lamp > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,707,141 A - Document ID: US5707141A - Status: Granted - Kind: A - Application number: 08/684,050 - Filed: 1996-07-22 - Granted: 1998-01-13 - Earliest claimed: 1995-07-28 - Assignees: Koito Manufacturing Co., Ltd. - Inventors: Norimasa Yamamoto; Masahiro Maeda - Web page: https://patentgrep.com/patent/US5707141A ## CPC - F21S 43/40: characterised by the combination of reflectors and refractors - F21S 41/168: having a filament arranged transversally to the optical axis of the illuminating device - F21S 41/333: {with discontinuity at the junction between adjacent areas} - F21S 41/337: {the reflector having a structured surface, e.g. with facets or corrugations} - F21S 43/10: characterised by the light source - F21S 43/26: {Refractors, transparent cover plates, light guides or filters not provided in groups F21S43/235 - F21S43/255} - F21S 43/31: Optical layout thereof - F21S: NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS ## Abstract A vehicle lamp which includes a reflection mirror, a front lens, and a light source arranged between the reflection mirror and the front lens. The central axis of the light source is perpendicular to the principal optical axis of the reflection mirror. On the reflection mirror, there is formed a reflection surface composed of a large number of reflection steps which are defined by portions of paraboloids of revolution and are formed between adjacent ones of closed curves. The closed curves are obtained as lines of intersection between a fundamental reflection surface and a group of paraboloids of revolution composed of a large number of paraboloids of revolution having different focal distances. Centers of the group of closed curves forming the boundaries of the reflection steps are arranged at a position distant from an intersection at which the principal optical axis of the reflection mirror crosses the reflection mirror, and square lens steps are formed on the front lens. Due to the foregoing, the arrangement of the image of the light source that has been projected by the reflection steps tend to be matched with the sections of the lens steps formed on the front lens. ## Claims ### Claim 1 A vehicle lamp comprising: a reflection mirror having a principal optical axis and comprising a reflection surface composed of a plurality of reflection steps which are defined by portions of paraboloids of revolution and formed between adjacent ones of closed curves, said closed curves being defined as lines of intersection between a group of paraboloids of revolution having a common axis but different focal distances and a fundamental surface for the reflection surface; a front lens arranged in front of the reflection mirror; and a light source arranged on said principal optical axis of the reflection mirror such that a central axis of said light source is perpendicular to said principal optical axis of the reflection mirror; wherein centers of the group of closed curves forming boundaries of the reflection steps are arranged at a position distant from an intersection at which the principal optical axis of the reflection mirror crosses the reflection mirror, and said front lens comprises lens steps in substantially square regions. ### Claim 2 (depends on 1) A vehicle lamp as claimed in claim 1, wherein said front lens steps are assembled in a grid arrangement. ### Claim 3 (depends on 1) A vehicle lamp as claimed in claim 1, wherein said vehicle lamp comprises at least two of a tail, stop and turn portions. ### Claim 4 (depends on 1) A vehicle lamp as claimed in claim 1, wherein said light source comprises a filament and the central axis of said filament is perpendicular to the principal optical axis of said reflecting mirror and extends in a horizontal direction. ### Claim 5 (depends on 1) A vehicle lamp as claimed in claim 1, wherein said light source comprises a filament and said reflection steps project images of said filament having a longitudinal central axis, said filament being oriented such that the longitudinal central axis of said images extend substantially in one of the horizontal or vertical directions. ### Claim 6 (depends on 5) A vehicle lamp as claimed in claim 5, wherein said filament images formed by each said reflection step comprises substantially a rectangle which extends along said longitudinal central axis of said filament image. ### Claim 7 (depends on 5) A vehicle lamp as claimed in claim 5, wherein said lens steps are shaped to diffuse said filament images in a longitudinal direction. ### Claim 8 (depends on 5) A vehicle lamp as claimed in claim 5, wherein said lens steps are shaped to diffuse said filament images in a direction orthogonal to said longitudinal central axis. ### Claim 9 (depends on 5) A vehicle lamp as claimed in claim 5 wherein said lens steps are shaped to control the degree of diffusion of said filament images. ### Claim 10 (depends on 5) A vehicle lamp as claimed in claim 5 wherein said lens steps comprise fisheye steps having a predetermined radius of curvature on at least one of said horizontal section and said vertical section. ### Claim 11 (depends on 2) A vehicle lamp as claimed in claim 2, wherein the shape of said lens steps in said grid substantially match the images reflected from corresponding reflecting steps.