Substrate-guided wave-based transparent holographic center high mounted stop light and method of fabrication thereof

Abstract

Multiple pairs of substrate-guided wave-based holograms (SGWHs) are laminated to a common thin substrate to form a transparent substrate-guided wave-based holographic CHMSL (SGWHC) that diffracts playback LED illumination over a wide angular range. This device is made pursuant to a technique that includes the steps of recording a first set of SGWHs with one setup, that upon playback, will couple and guide the diffracted light inside the substrate, and a second set of SGWHs recorded with another setup, that will diffract and couple the guided light out.

1 .- 10 . (canceled) 
     
     
         11 . A light assembly comprising:
 (a) a transparent light guide plate comprising a specific index of refraction;   (b) two holograms secured to a same face and opposite ends of the light guide plate;
 wherein each hologram comprises an index of refraction similar to that of the index of refraction of the light guide plate; and 
   (c) one LED module near the light guide plate on an opposite face relative to the first hologram;
 wherein the LED module comprises a specific beam divergency and wavelength bandwidth so as to produce divergent light beams that will pass through the light guide plate then illuminate the first hologram at Bragg conditions and will be diffracted in the light guide plate; and 
 wherein the diffracted beams will propagate along the light guide plate undergoing total internal reflection and will illuminate at Bragg condition the second hologram, which then will couple the diffused beams outside of the light guide plate at a specific divergency and direction to produce emitted light beams. 
   
     
     
         12 . The light assembly of  claim 11  wherein a recording beam angle of the first hologram matches the specific LED beam divergency, direction and wavelength. 
     
     
         13 . The light assembly of  claim 11  wherein the light guide plate comprises a transparent material comprising glass, polycarbonate, acrylic, or mixtures thereof. 
     
     
         14 . The light assembly of  claim 11  wherein the light guide plate comprises a thickness of about 6 mm. 
     
     
         15 . The light assembly of  claim 11  wherein the light guide plate comprises a length of about 200 mm and a width of about 350 mm. 
     
     
         16 . The light assembly of  claim 11  wherein the light guide plate comprises a width similar to that of a rear-mounted stop light of an automobile. 
     
     
         17 . The light assembly of  claim 11  wherein the light guide plate comprises a length of about 200 mm and a width of about 350 mm. 
     
     
         18 . The light assembly of  claim 11  wherein the emitted beams of light comprise a length of about 14 inches and a height of about 2 inches. 
     
     
         19 . The light assembly of  claim 11  wherein the first hologram comprises a size of about 20 mm by 20 mm. 
     
     
         20 . The light assembly of  claim 11  wherein the second hologram comprises a size of about 50 mm by 50 mm. 
     
     
         21 . The light assembly of  claim 11  wherein each of the two holograms comprises a thin film material. 
     
     
         22 . The light assembly of  claim 11  wherein each of the two holograms comprises polycarbonate or polyester. 
     
     
         23 . The light assembly of  claim 11  wherein the emitted beams of light comprise an image comprising a symbol, a letter, or mixtures thereof. 
     
     
         24 . The light assembly of  claim 11  wherein the first hologram is recorded at an appropriate angle with red lasers at 632 nm or 647 nm. 
     
     
         25 . The light assembly of  claim 11  wherein the holograms are either reflective or transmissive or a combination thereof. 
     
     
         26 . The light assembly of  claim 11  wherein the LED comprises a red LED having a beam divergency of 120 degrees and a peak wavelength of 635 nm. 
     
     
         27 . The light assembly of  claim 11  wherein each of the two holograms comprise a polyethylene naphthalate film or a polyethylene terephthalate film. 
     
     
         28 . The light assembly of  claim 11  mounted on or above a window of a vehicle. 
     
     
         29 . The light assembly of  claim 11  mounted center-high on or above a rear window of a vehicle. 
     
     
         30 . The light assembly of  claim 11  wherein the coupled-out beam comprises an arrow.