Diffraction efficiency control in holographic elements
US5278008A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 1992 |
| Grant date | Jan 11, 1994 |
| Priority date | — |
| Expiry date | Nov 6, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H2260/30
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method for precisely controlling the overall average diffraction efficiency of a hologram including the steps of (a) providing a hologram layer that includes a hologram formed pursuant to hologram forming exposure and development, (b) coating the hologram layer with a photoresist layer, (c) masking the photoresist layer with a mask having opaque and transparent areas wherein the proportion of the opaque areas relative to the transparent areas is selected pursuant to the desired diffraction efficiency, the opaque and transparent areas being sufficiently small so as to have little noticeable effect when the resulting hologram is played back, (d) exposing the photoresist layer to actinic illumination through the mask transparent areas, (e) developing the photoresist layer to remove the photoresist in the areas illuminated by the actinic illumination to uncover the areas of the recording material corresponding to the transparent areas of the mask, (f) etching the recording material to remove the areas thereof that were uncovered by etching of the photoresist, and (g) removing the remaining photoresist. The formation of the hologram can be at an effective exposure in the saturated reg…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.