Keypad assembly

Abstract

Disclosed is a keypad assembly including a light guide panel, light, at least one light extracting pattern provided on the light guide panel so that light propagating inside the light guide panel is directed out of the light guide panel, a switch board having at least one switch; and at least one light source for coupling light to the inside of the light guide panel, wherein the light guide panel has a thickness of 0.03-0.6 mm.

What is claimed is: 
     
       1. A keypad assembly comprising:
 a light guide panel made of a rubber-based material and having a thickness of 0.3-0.4 mm; 
 at least one light extracting pattern provided on the light guide panel so that light propagating inside the light guide panel is directed out of the light guide panel; 
 a switch board having at least one switch; and 
 at least one light source for coupling light to the inside of the light guide panel. 
 
     
     
       2. The keypad assembly as claimed in  claim 1 , wherein a distance between the light guide panel and the light source is equal to or smaller than 0.75 mm. 
     
     
       3. The keypad assembly as claimed in  claim 2 , wherein the distance between the light guide panel and the light source is equal to or smaller than 0.5 mm. 
     
     
       4. The keypad assembly as claimed in  claim 1 , further comprising:
 a key sheet having at least one key button and a film, the at least one key button formed on an upper surface of the film. 
 
     
     
       5. The keypad assembly as claimed in  claim 4 , wherein an air layer is maintained between, the film and the light guide panel. 
     
     
       6. The keypad assembly as claimed in  claim 4 , wherein the film is attached to an upper surface of the light guide panel. 
     
     
       7. The keypad assembly as claimed in  claim 1 , wherein the light guide panel has at least one protrusion formed on a lower surface of the light guide panel. 
     
     
       8. The keypad assembly as claimed in  claim 7 , wherein the light extracting pattern is formed on the lower surface of the light guide panel around the protrusion. 
     
     
       9. The keypad assembly as claimed in  claim 1 , wherein a peripheral portion of the light guide panel bends and extends to an upper surface of the switch board. 
     
     
       10. The keypad assembly as claimed in  claim 1 , wherein the light guide panel is adapted to regain an original shape after being deformed by external pressure. 
     
     
       11. The keypad assembly as claimed in  claim 4 , wherein the key sheet has at least one protrusion formed on a lower surface of the film. 
     
     
       12. The keypad assembly as claimed in  claim 8 , wherein a density of said light extracting pattern increases in the direction of light propagating through the light guide panel. 
     
     
       13. The keypad assembly as claimed in  claim 8 , wherein elements of said light extracting pattern are in a V-shape. 
     
     
       14. The keypad assembly as claimed in  claim 1 , wherein said light source provides a luminance between 1200 and 1600 mcd. 
     
     
       15. A keypad assembly comprising:
 a light guide panel made of a rubber-based material and having a thickness of 0.3-0.4 mm; 
 at least one light extracting pattern composed of a plurality of V-shaped elements on the light guide panel, wherein the density of the light extracting pattern increases in the direction of the light propagating inside the light guide; 
 a switch board having at least one switch; and 
 at least one light source for coupling light to the inside of the light guide panel. 
 
     
     
       16. The keypad assembly as claimed in  claim 15 , wherein the light guide panel is composed of a material having a self-restoring property when, deformed. 
     
     
       17. The keypad assembly as claimed in  claim 15 , wherein a distance between the light guide panel and the light source is equal to or smaller than 0.75 mm. 
     
     
       18. The keypad assembly as claimed in  claim 1 , wherein the light source is positioned on the switch board and a peripheral portion of the light guide panel extends to the light source. 
     
     
       19. The keypad assembly as claimed in  claim 15 , further comprising:
 a key sheet having at least one key button and a film, the at least one key button formed on, an upper surface of the film, wherein the film is attached to the light guide panel such that an air layer is maintained between the film and the light guide panel. 
 
     
     
       20. A keypad assembly comprising:
 a light guide plate made of polycarbonate and having a thickness of 0.03 mm-0.2 mm;   at least one light extracting pattern provided on the light guide plate so that light propagating inside the light guide plate is directed out of the light guide plate;   a switch board having at least one switch; and   at least one light source for coupling light to the inside of the light guide plate.    
     
     
       21. The keypad assembly as claimed in claim 20, further comprising: a key sheet having at least one key button and a film, the at least one key button formed on an upper surface of the film.  
     
     
       22. The keypad assembly as claimed in claim 21, wherein an air layer is maintained between the film and the light guide plate.  
     
     
       23. The keypad assembly as claimed in claim 20, further comprising at least one protrusion positioned between the light guide plate and the switch.  
     
     
       24. The keypad assembly as claimed in claim 21, wherein the light extracting pattern is formed on the light guide plate and corresponds to the key button.  
     
     
       25. The keypad assembly as claimed in claim 24, wherein a density of said light extracting pattern increases in the direction of light propagating through the light guide plate.  
     
     
       26. A keypad assembly comprising:
 a light guide plate made of polyurethane and having a thickness of 0.03 mm-0.2 mm;   at least one light extracting pattern provided on the light guide plate so that light propagating inside the light guide plate is directed out of the light guide plate;   a switch board having at least one switch; and   at least one light source for coupling light to the inside of the light guide plate.    
     
     
       27. A keypad assembly comprising:
 a light guide plate made of polymethylmethacrylate (PMMA) and having a thickness of 0.03 mm-0.2 mm;   at least one light extracting pattern provided on the light guide plate so that light propagating inside the light guide plate is directed out of the light guide plate;   a switch board having at least one switch; and   at least one light source for coupling light to the inside of the light guide plate.