Placido projector for corneal topography system

Abstract

A placido projector for a corneal topography system includes a substrate having dielectric phosphor. The substrate is configured to be activated by electric current and responsive to emit light. A plurality of opaque, concentric rings are formed on the substrate. When the substrate emits light responsive to the electric current, a placido image is projected. The concentric rings can be formed using silk screening or other techniques. The dielectric phosphor can be micro-encapsulated and deposited onto the substrate. The substrate may be an electro-luminance panel. A protective cover is placed adjacent to the substrate to retain the substrate in a predetermined shape. In one embodiment, the placido projector has a frusto conical shape.

1 . A placido projector for a corneal topography system, comprising:
 An electroluminance panel having a substrate having dielectric phosphor, the substrate configured to be activated by electric current and responsive to emit light, the substrate being deposited with micro encapsulated phosphor; and   an opaque pattern formed on the substrate, wherein a placido image is projected when the substrate emits light responsive to the electric current.   
   
   
       2 . The placido projector of  claim 1 , wherein the pattern is a plurality of concentric rings formed on the substrate. 
   
   
       3 . The placido projector of  claim 1 , wherein the opaque pattern is formed on the substrate by silk screening. 
   
   
       4 . The placido projector of  claim 1 , wherein the substrate is activated by alternating current (AC). 
   
   
       5 . The projector of  claim 1 , further comprising a cover placed adjacent to the substrate to retain the substrate in a predetermined shape. 
   
   
       6 . An electrolumunance panel having a substrate having dielectric phosphor, the substrate being deposited with micro encapsulated phosphor;
 the substrate configured to be activated by electric current and responsive to emit light, an opaque pattern formed on the substrate,   wherein a placido image is projected when the substrate emits light responsive to the electric current.   
   
   
       7 . The substrate of  claim 6 , wherein the pattern is a plurality of concentric rings formed on the substrate. 
   
   
       8 . The substrate of  claim 6 , wherein the opaque pattern is formed on the substrate by silk screening. 
   
   
       9 . The placido projector of  claim 6 , wherein the substrate is activated by alternating current (AC).