Backlight for color liquid crystal display apparatus

Abstract

A backlight for a color liquid crystal display apparatus includes a first light-guide plate; a first incidence part for receiving light of a first primary color in a first area on a first lateral surface of the first light-guide plate; a second incidence part for receiving light of a second primary color light in a second area on a second lateral surface that is opposite to the first lateral surface of the first light-guide plate; and a third incidence part for receiving light of a third primary color in a third area on a rear surface of the first light-guide plate. The number of superposition steps is thereby reduced, light-guide plates can easily be superposed onto an LCD panel with high accuracy, and a lightweight and inexpensive backlight for a color liquid crystal display apparatus can be obtained.

What is claimed is: 
     
       1. A backlight for a color liquid crystal display apparatus wherein light of the three primary colors of red, blue, and green is directly incident on the corresponding pixels of a liquid crystal layer, said backlight comprising:
 a first light-guide plate; 
 a first incidence part for receiving light of a first primary color from among the light of the three primary colors in a first area on a first lateral edge surface of the first light-guide plate; 
 a second incidence part for receiving light of a second primary color light from among the light of the three primary colors in a second area on a second lateral edge surface of the first light-guide plate that is opposite to the first lateral edge surface of the first light-guide plate; and 
 a third incidence part for receiving light of a third primary color from among the light of the three primary colors in a third area on a rear surface of the first light-guide plate. 
 
     
     
       2. The backlight according to  claim 1 , wherein:
 the first incidence part has a first light-emitting diode that emits light of the first primary color and is provided to the first lateral edge surface, and a first light-blocking film provided to an area outside of the first area on the first lateral edge surface; 
 the second incidence part has a second light-emitting diode that emits light of the second primary color and is provided to the second lateral edge surface, and a second light-blocking film provided to an area outside of the second area on the second lateral edge surface; and 
 the third incidence part has a second light-guide plate provided to the rear surface of the first light-guide plate, a third light-blocking film provided to an area outside of the third area on the rear surface, and a third light-emitting diode for emitting light of the third primary color toward the second light-guide plate. 
 
     
     
       3. The backlight according to  claim 2 , wherein the area occupied by light of the first primary color received from the first area, the area occupied by light of the second primary color received from the second area, and the area occupied by light of the third primary color received from the third area in the first light-guide plate are disposed in an alternating fashion parallel to each other in the shape of a band as viewed from an emitting surface. 
     
     
       4. The backlight according to claim  1  2, wherein a prism is formed on the surfaces of the first and second light-guide plates, and directivity of light emitted from the first and second light-guide plates is enhanced. 
     
     
       5. The backlight according to  claim 2 , wherein a prism is formed on the surfaces of the first and second light-guide plates, and directivity of light emitted from the first and second light-guide plates is enhanced. 
     
     
       6. The backlight according to  claim 3 , wherein a prism is formed on the surfaces of the first and second light-guide plates, and directivity of light emitted from the first and second light-guide plates is enhanced. 
     
     
       7. The backlight according to claim  1  2, wherein
 concavities and convexities that scatter light are formed on the surfaces of the first and second light-guide plates; and 
 the light emitted from the first and second light-guide plates is diffused. 
 
     
     
       8. The backlight according to  claim 2 , wherein
 concavities and convexities that scatter light are formed on the surfaces of the first and second light-guide plates; and 
 the light emitted from the first and second light-guide plates is diffused. 
 
     
     
       9. The backlight according to  claim 3 , wherein
 concavities and convexities that scatter light are formed on the surfaces of the first and second light-guide plates; and 
 the light emitted from the first and second light-guide plates is diffused. 
 
     
     
       10. The backlight for a color liquid crystal display apparatus according to claim  1  2, wherein a scattering sheet capable of alternating between a scattering state and a transmitting state depending on an electronic signal is formed on the surfaces of the first and second light-guide plates. 
     
     
       11. The backlight for a color liquid crystal display apparatus according to  claim 2 , wherein a scattering sheet capable of alternating between a scattering state and a transmitting state depending on an electronic signal is formed on the surfaces of the first and second light-guide plates. 
     
     
       12. The backlight for a color liquid crystal display apparatus according to  claim 3 , wherein a scattering sheet capable of alternating between a scattering state and a transmitting state depending on an electronic signal is formed on the surfaces of the first and second light-guide plates. 
     
     
       13. A color liquid crystal display apparatus comprising a liquid crystal layer and a backlight for the color liquid crystal display apparatus in which light of the three primary colors of red, blue, and green is directly incident on the corresponding pixels of the liquid crystal layer, the backlight having:
 a first light-guide plate; 
 a first incidence part for receiving light of a first primary color from among the light of the three primary colors in a first area on a first lateral edge surface of the first light-guide plate; 
 a second incidence part for receiving light of a second primary color light from among the light of the three primary colors in a second area on a second lateral edge surface of the first light-guide plate that is opposite to the first lateral edge surface of the first light-guide plate; and 
 a third incidence part for receiving light of a third primary color from among the light of the three primary colors in a third area on a rear surface of the first light-guide plate. 
 
     
     
       14. The apparatus of  claim 13 , wherein
 the first incidence part has a first light-emitting diode that emits light of the first primary color and is provided to the first lateral edge surface, and a first light-blocking film provided to an area outside of the first area on the first lateral edge surface; 
 the second incidence part has a second light-emitting diode that emits light of the second primary color and is provided to the second lateral edge surface, and a second light-blocking film provided to an area outside of the second area on the second lateral edge surface; and 
 the third incidence part has a second light-guide plate provided to the rear surface of the first light-guide plate, a third light-blocking film provided to an area outside of the third area on the rear surface, and a third light-emitting diode for emitting light of the third primary color toward the second light-guide plate. 
 
     
     
       15. An apparatus, comprising:
 a light-guide plate;   a first incidence part configured to receive light of a first primary color on a first edge surface of the light-guide plate;   a second incidence part configured to receive light of a second primary color on a second edge surface different from the first edge surface of the light-guide plate; and   a third incidence part configured to receive light of a third primary color on a rear surface of the light-guide plate.    
     
     
       16. The apparatus of claim 15, wherein the third incidence part comprises a second light-guide plate disposed on the rear surface of the light-guide plate.  
     
     
       17. The apparatus of claim 16, further comprising:
 a first light-emitting diode configured to emit light of the first primary color to a first area of the first edge surface;   a second light-emitting diode configured to emit light of the second primary color to a second area of the second edge surface; and   a third light-emitting diode for emitting light of the third primary color toward the second light-guide plate for receipt by a third area on the rear surface.    
     
     
       18. The apparatus of claim 17, wherein:
 the first incidence part comprises a first light-blocking film disposed on an area outside of the first area on the first edge surface;   the second incidence part comprises a second light-blocking film disposed on an area outside of the second area on the second edge surface; and   the third incidence part comprises a third light-blocking film disposed on an area outside of the third area on the rear surface.    
     
     
       19. The apparatus of claim 18, wherein an area occupied by light of the first primary color received from the first area, an area occupied by light of the second primary color received from the second area, and an area occupied by light of the third primary color received from the third area are disposed in an alternating fashion parallel to each other in a shape of a band.  
     
     
       20. The apparatus of claim 15, wherein a prism is formed on a surface of the light-guide plate.  
     
     
       21. The apparatus of claim 18, wherein a prism is formed on a surface of the light-guide plate.  
     
     
       22. The apparatus of claim 19, wherein a prism is formed on a surface of the light-guide plate.  
     
     
       23. The apparatus of claim 15, wherein concavities and convexities are formed on a surface of the light-guide plate.  
     
     
       24. The apparatus of claim 18, wherein concavities and convexities are formed on a surface of the light-guide plate.  
     
     
       25. The apparatus of claim 19, wherein concavities and convexities are formed on a surface of the light-guide plate.  
     
     
       26. The apparatus claim 15, further comprising a scattering sheet configured to alternate between a scattering state and a transmitting state in accordance with a signal, wherein the scattering sheet is formed on a surface of the light-guide plate.  
     
     
       27. The apparatus of claim 18, further comprising a scattering sheet configured to alternate between a scattering state and a transmitting state in accordance with a signal, wherein the scattering sheet is formed on a surface of the light-guide plate.  
     
     
       28. The apparatus of to claim 19, further comprising a scattering sheet configured to alternate between a scattering state and a transmitting state in accordance with a signal, wherein the scattering sheet is formed on a surface of the light-guide plate.  
     
     
       29. An apparatus, comprising:
 first means for guiding light including:
 first means for receiving light of a first primary color on a first edge surface of the first means for guiding light; 
 second means for receiving light of a second primary color on a second edge surface of the first means for guiding light different from the first edge surface; and 
 third means for receiving light of a third primary color on a rear surface of the first means for guiding light via a second means for guiding light on the rear surface of the first means for guiding light.  
   
     
     
       30. The apparatus of claim 29, further comprising:
 means for emitting light of the first primary color to a first area of the first edge surface;   means for emitting light of the second primary color to a second area of the second edge surface; and   means for emitting light of the third primary color toward the second means for guiding light for receipt by a third area of the rear surface.    
     
     
       31. The apparatus of claim 30, wherein:
 the first means for receiving light includes first means for blocking the light of the first primary color on a first external area outside of the first area on the first edge surface;   the second means for receiving light includes second means for blocking the light of the second primary color on a second external area outside of the second area on the second edge surface; and   the third means for receiving light includes third means for blocking the light of the third primary color on a third external area outside of the third area on the rear surface.    
     
     
       32. The apparatus of claim 29, wherein the first means for guiding light includes means for diffusing light on at least one surface of the first means for guiding light.  
     
     
       33. The apparatus of claim 31, wherein the first means for guiding light includes means for diffusing light on at least one surface of the first means for guiding light.  
     
     
       34. The apparatus of claim 29, further comprising means for scattering light emitted by the first means for guiding light.  
     
     
       35. The apparatus of claim 31, further comprising means for scattering light emitted by the first means for guiding light.  
     
     
       36. A method, comprising:
 receiving light of a first primary color on a first edge surface of a first light-guide plate;   receiving light of a second primary color on a second edge surface of the first light-guide plate different from the first edge surface; and   receiving light of a third primary color on a rear surface of the first light-guide plate via a second light-guide plate on the rear surface.    
     
     
       37. The method of claim 36, wherein:
 the receiving the light of the first primary color includes receiving the light of the first primary color on a first area of the first edge surface;   the receiving the light of the second primary color includes receiving the light of the second primary color on a second area of the second edge surface; and   the receiving the light of the third primary color includes receiving the light of the third primary color on a third area of the rear surface via the second light-guide plate.    
     
     
       38. The method of claim 37, further comprising
 blocking the light of the first primary color from a first outside area outside of the first area on the first edge surface;   blocking the light of the second primary color from a second outside area outside of the second area on the second edge surface; and   blocking the light of the third primary color from a third outside area outside of the third area on the rear surface.    
     
     
       39. The method of claim 36, further comprising enhancing a directivity of light emitted from the first light-guide plate using a prism formed on a surface of the first light-guide plate.  
     
     
       40. The method of claim 38, further comprising enhancing a directivity of light emitted from the first light-guide plate using a prism formed on a surface of the first light-guide plate.  
     
     
       41. The method of claim 36, further comprising diffusing light emitted from the first light-guide plate using concavities and convexities formed on a surface of the first light-guide plate.  
     
     
       42. The method of claim 38, further comprising diffusing light emitted from the first light-guide plate using concavities and convexities formed on a surface of the first light-guide plate.  
     
     
       43. The method of claim 36, further comprising scattering light emitted from the first light-guide plate using a scattering sheet formed on a surface of the first light-guide plate.  
     
     
       44. The method of claim 43, further comprising transitioning the scattering sheet between a scattering state and a transmitting state in response to a signal.  
     
     
       45. The method of claim 38, further comprising scattering light emitted from the first light-guide plate using a scattering sheet formed on a surface of the first light-guide plate.  
     
     
       46. The method of claim 45, further comprising transitioning the scattering sheet between a scattering state and a transmitting state in response to a signal.