Lighting unit, liquid crystal display, and electronic apparatus

Abstract

An end of a light guide plate used for a liquid crystal display and a lighting unit, which is positioned on one side in a first direction, is provided with a depressed portion, and another end of the light guide plate, which is positioned on the other side in the first direction, is provided with a projecting portion. Using the depressed portion and the projecting portion, the light guide plate is placed in a predetermined position of a frame body. The depressed portion and the projecting portion are formed at positions opposite each other in the first direction, and the projecting portion is equal to or smaller than the depressed portion in size.

What is claimed is: 
     
       1. A lighting unit comprising:
 a light guide plate; 
 a light source that is provided on along a side of an end face of the light guide plate serving as a light incident face; and 
 a frame body that holds the light guide plate and the light source, wherein 
 the light guide plate includes:
 a depressed portion that is depressed from a first side of the light guide plate in a first direction; and 
 a projecting portion that projects from a second side of the light guide plate in the first direction, the second side being opposite to the first side, and that is formed at a position on the second side so as to be opposite to the depressed portion, wherein 
 
 a length of the projecting portion in a second direction that crosses the first direction, the first direction and the second direction being in-plane directions, is equal to or smaller than a length of the depressed portion in the second direction, and 
 a length of the projecting portion in the first direction is equal to or smaller than a length of the depressed portion in the first direction 
 the frame body includes a first positioning projection, a second positioning projection, a third positioning projection and a fourth positioning projection, 
 the first positioning projection abuts the projecting portion and the second positioning projection abuts the projecting portion with respect to the first positioning projection in the second direction, 
 the third positioning projection abuts a first inside face of the depressed portion and the fourth positioning projection abuts a second inside face of the depressed portion, the first inside face and the second inside face are positioned opposite to each other with respect to the depressed portion in the second direction, and 
 the first positioning projection and the third positioning projection are positioned at the same position in the second direction so as to be opposite each other in the first direction, and the second positioning projection and the fourth positioning projection are positioned at the same position in the second direction so as to be opposite each other in the first direction. 
 
     
     
       2. The lighting unit according to  claim 1 , wherein the length of the projecting portion of the light guide plate in the first direction and the length of the depressed portion of the light guide plate in the first direction are equal to each other. 
     
     
       3. The lighting unit according to  claim 1 , wherein the frame body includes:
 a first positioning projection that abuts a first inside face of the depressed portion of the light guide plate, the first inside face being positioned on one side in the second direction; 
 a second positioning projection that abuts a second inside face of the depressed portion of the light guide plate, the second inside face being positioned on another side in the second direction; 
 a third positioning projection that abuts a first outside face of the projecting portion of the light guide plate, the first outside face being positioned on the one side in the second direction; and 
 a fourth positioning projection that abuts a second outside face of the projecting portion of the light guide plate, the second outside face being positioned on the other side in the second direction first positioning projection, the second positioning projection, the third positioning projection and the fourth positioning projection are positioned on the frame body and penetrate the frame body from outside of the frame body. 
 
     
     
       4. The lighting unit according to  claim 3 , wherein
 the first positioning projection and the third positioning projection are of equal size in the second direction and are formed at the same position in the second direction so as to be opposite each other in the first direction, and   the second positioning projection and the fourth positioning projection are of equal size in the second direction and are formed at the same position in the second direction so as to be opposite each other in the first direction.   
     
     
       5. The lighting unit according to  claim 1 , further comprising an optical sheet placed so as to be stacked over the light guide plate, wherein
 the optical sheet includes:
 a sheet-side depressed portion that is depressed from a first side of the optical sheet in the first direction; and 
 a sheet-side projecting portion that projects from a second side of the optical sheet in the first direction, the second side of the optical sheet being opposite the first side of the optical sheet, and that is formed at a position on the second side of the optical sheet so as to be opposite the sheet-side depressed portion, wherein 
   a length of the sheet-side projecting portion in the second direction is equal to or smaller than a length of the sheet-side depressed portion in the second direction, and   a length of the sheet-side projecting portion in the first direction is equal to or smaller than a length of the sheet-side depressed portion in the first direction.   
     
     
       6. The lighting unit according to  claim 5 , wherein, when viewed in a third direction that crosses the first direction and the second direction,
 the sheet-side depressed portion of the optical sheet overlaps the depressed portion of the light guide plate, and   the sheet-side projecting portion of the optical sheet overlaps the projecting portion of the light guide plate.   
     
     
       7. The lighting unit according to  claim 1 , wherein an end of the light guide plate positioned in the second direction is used as the light incident face. 
     
     
       8. A liquid crystal display comprising the lighting unit according to  claim 1 , the liquid crystal display including a liquid crystal panel placed so as to be stacked on a light emitting face of the light guide plate. 
     
     
       9. An electronic apparatus comprising the liquid crystal display according to  claim 8 . 
     
     
       10. The lighting unit according to claim 1, further comprising a second frame body which holds the light source between the frame body, wherein
 the second frame body covers the first positioning projection, the second positioning projection, the third positioning projection and the fourth positioning projection when viewed from a normal direction of the light guide plate.    
     
     
       11. The lighting unit according to claim 10, wherein the second frame body overlaps a peripheral area of the light guide plate when viewed from the normal direction of the light guide plate.  
     
     
       12. The lighting unit according to claim 10, wherein the second frame body abuts the first positioning projection, the second positioning projection, the third positioning projection and the fourth positioning projection.  
     
     
       13. The lighting unit according to claim 1, wherein the light guide plate includes a first face served as a light emitting face, and a second face opposite to the first face, wherein
 the second face includes a diffusion area on which a plurality of diffusion patterns are formed, and peripheral area positioned between an edge of the second face and the diffusion area, and   the diffusion area is apart from the depressed portion.    
     
     
       14. A lighting unit comprising:
 a light guide plate;   a light source that is provided along a side end face of the light guide plate serving as a light incident face; and   a frame body that holds the light guide plate and the light source, wherein   the light guide plate includes:
 a first face served as a light emitting face, and a second face opposite to the first face, 
 a depressed portion that is depressed from a first side of the light guide plate in a first direction being an in-plane direction; and 
 a projecting portion that projects from a second side of the light guide plate in the first direction, the second side being opposite to the first side, wherein 
   the second face includes a diffusion area on which a plurality of diffusion patterns are formed, and a peripheral area positioned between the edge of the second face and the diffusion area,   the diffusion area is apart from the depressed portion,   the frame body includes a first positioning projection, a second positioning projection, a third positioning projection and a fourth positioning projection,   the first positioning projection abuts the projecting portion and the second positioning projection abuts the projecting portion with respect to the first positioning projection in the second direction,   the third positioning projection abuts a first inside face of the depressed portion and the fourth positioning projection abuts a second inside face of the depressed portion, the first inside face and the second inside face are positioned opposite each other with respect to the depressed portion in the second direction, and   the first positioning projection and the third positioning projection are positioned at the same position in the second direction so as to be opposite each other in the first direction, and the second positioning projection and the fourth positioning projection are positioned at the same position in the second direction so as to be opposite each other in the first direction.    
     
     
       15. The lighting unit according to claim 14, wherein the projecting portion is formed at a position on the second side so as to be opposite to the depressed portion.  
     
     
       16. The lighting unit according to claim 14, wherein a length of the projecting portion in a second direction that crosses the first direction, the second direction being an in-plane direction, is equal to or smaller than a length of the depressed portion in the second direction.  
     
     
       17. The lighting unit according to claim 14, wherein the first positioning projection, the second positioning projection, the third positioning projection and the fourth positioning projection are positioned on the frame body and penetrate the frame body from outside of the frame body.  
     
     
       18. The lighting unit according to claim 14, further comprising a second frame body which holds the light source between the frame body, wherein
 the second frame body covers the first positioning projection, the second positioning projection, the third positioning projection and the fourth positioning projection when viewed from a normal direction of the light guide plate.    
     
     
       19. The lighting unit according to claim 18, wherein the second frame body overlaps a peripheral area of the light guide plate when viewed from the normal direction of the light guide plate.  
     
     
       20. The lighting unit according to claim 18, wherein the second frame body abuts the first positioning projection, the second positioning projection, the third positioning projection and the fourth positioning projection.  
     
     
       21. A liquid crystal display comprising the lighting unit according to claim 14, the liquid crystal display including a liquid crystal panel placed so as to be stacked on a light emitting face of the light guide plate.  
     
     
       22. An electronic apparatus comprising the liquid crystal display according to claim 21.  
     
     
       23. A lighting unit comprising:
 a light guide plate;   a light source that is provided along a side end face of the light guide plate serving as a light incident face;   a frame body that holds the light guide plate and the light source; and   a reflection sheet disposed between the light guide plate and the frame body, wherein   the light guide plate includes:
 a first depressed portion that is depressed from a first side of the light guide plate in a first direction; and 
 a first projecting portion that projects from a second side of the light guide plate in the first direction, the second side being opposite to the first side, and is formed at a position on the second side so as to be opposite to the first depressed portion, wherein 
   a length of the first projecting portion in a second direction that crosses the first direction, the first direction and the second direction being in-plane directions, is equal to or smaller than a length of the first depressed portion in the second direction,   the reflection sheet includes a second depressed portion that is corresponding to the first depressed portion and depressed toward the first direction, and a second projecting portion that is corresponding to the first projection portion and projects toward the first direction,   the frame body includes a first positioning projection, a second positioning projection, a third positioning projection and a fourth positioning projection,   the first positioning projection abuts the first projecting portion and the second positioning projection abuts the first projecting portion with respect to the first positioning projection in the second direction, and   the third positioning projection abuts a first inside face of the first depressed portion and the fourth positioning projection abuts a second inside face of the first depressed portion, the first inside face and the second inside face are positioned opposite to each other with respect to the depressed portion in the second direction,   the first positioning projection and the third positioning projection are positioned at the same position in the second direction so as to be opposite each other in the first direction, and the second positioning projection and the fourth positioning projection are positioned at the same position in the second direction so as to be opposite each other in the first direction.    
     
     
       24. The lighting unit according to claim 23, wherein
 the first positioning projection abuts the second projecting portion and the second positioning projection abuts the second projecting portion with respect to the first positioning projection in the second direction, and   the third positioning projection abuts a first inside face of the second depressed portion and the fourth positioning projection abuts a second inside face of the second depressed portion, the first inside face and the second inside face are positioned opposite to each other with respect to the depressed portion in the second direction.