Lens array, manufacturing method of lens array, illumination optical device, and projector

Abstract

Molten glass (G) is set and press-molded in a molding die ( 60 ) having dies ( 621 A 1, 621 A 2 ) corresponding to a lens array. After the molding, the molded article is removed from the molding die ( 60 ) and separated by bending at a bend-separation face ( 121 C), which is a boundary part of adjacent lens arrays, so that two lens arrays are produced.

1 . A lens array manufactured by press-molding a molten optical material in a molding die having a plurality of dies corresponding to the lens array, comprising: 
 a base with a shape of substantially rectangular plate; and a dome-shaped lens section formed on one face of the base and having a plurality of small lenses,    wherein at least one lateral face out of four lateral faces of the base is a bend-separation face separated by a bend-separation.    
   
   
       2 . The lens array according to  claim 1 , 
 wherein the lens section has an optically operative lens area and a dummy area extended from the lens area toward the outer side of the lens array, and    wherein the dummy area is formed at least on outermost small lenses that are press-molded at the outer periphery of the molding die when press-molded in the molding die.    
   
   
       3 . The lens array according to  claim 2 , wherein the dummy area is an area extended from the lens area toward the outer side of the lens array in a range of 0.5 to 2.0 mm.  
   
   
       4 . The lens array according to  claim 1 , wherein the lens section is formed in a substantially rectangular shape in plan view with four chamfered corners, and a peripheral edge of the lens section is a slant face that is slanted from the inner side of the lens section toward the outer side to be angled with respect to the one face of the base.  
   
   
       5 . The lens array according to  claim 1 , wherein the plurality of small lenses of the lens section are connected with little height difference at a connected part of each other.  
   
   
       6 . The lens array according to  claim 1 , 
 wherein the base has a flat section where the thickness of the base is equal, the flat section surrounding an area where the plurality of small lenses are formed, and    wherein a step projected or recessed from the flat section is formed at a position on an end face as the bend-separation face.    
   
   
       7 . An illumination optical device comprising: a light source; a first lens array for splitting a light beam irradiated from the light source into a plurality of sub-beams; and a second lens array for focusing the sub-beams on an illuminated area, the illumination optical device superposing the sub-beams on the illuminated area, 
 wherein the first lens array and/or the second lens array is manufactured by press-molding a molten optical material in a molding die having a plurality of dies corresponding to the first lens array and/or the second lens array,    wherein the first lens array and/or the second lens array includes a base with a shape of substantially rectangular plate, and a dome-shaped lens section formed on one face of the base and having a plurality of small lenses arranged in a matrix form, and    wherein at least one lateral face out of four lateral faces of the base is a bend-separation face separated by a bend-separation.    
   
   
       8 . The illumination optical device according to  claim 7 , 
 wherein the lens section has an optically operative lens area and a dummy area extended from the lens area toward the outer side of the lens array, and    wherein the dummy area is formed at least on outermost small lenses that are press-molded at the outer periphery of the molding die when press-molded in the molding die.    
   
   
       9 . The illumination optical device according to  claim 8 , wherein the dummy area is an area extended from the lens area toward the outer side of the lens array in a range of 0.5 to 2.0 mm.  
   
   
       10 . The illumination optical device according to  claim 7 , wherein the lens section is formed in a substantially rectangular shape in plan view with four chamfered corners, and a peripheral edge of the lens section is a slant face that is slanted from the inner side of the lens section toward the outer side to be angled with respect to the one face of the base.  
   
   
       11 . The illumination optical device according to  claim 7 , wherein the plurality of small lenses of the lens section are connected with little height difference at a connected part of each other.  
   
   
       12 . The illumination optical device according to  claim 7 , 
 wherein the base has a flat section where the thickness of the base is equal, the flat section surrounding an area where the plurality of small lenses are formed, and    wherein a step projected or recessed from the flat section is formed at a position on an end face as the bend-separation face.    
   
   
       13 . A projector comprising: 
 an illumination optical device including: a light source; a first lens array for splitting a light beam irradiated from the light source into a plurality of sub-beams; and a second lens array for focusing the sub-beams on an illuminated area, the illumination optical device superposing the sub-beams on the illuminated area;    an optical modulator for modulating a light beam irradiated from the illumination optical device in accordance with image information to form an optical image; and    a projection optical device for projecting the optical image in an enlarged manner,    wherein the first lens array or/and the second lens array is manufactured by press-molding a molten optical material in a molding die having a plurality of dies corresponding to the first lens array and/or the second lens array,    wherein the first lens array and/or the second lens array includes a base with a shape of substantially rectangular plate, and a dome-shaped lens section formed on one face of the base and having a plurality of small lenses arranged in a matrix form, and    wherein at least one lateral face out of four lateral faces of the base is a bend-separation face separated by a bend-separation.    
   
   
       14 . The projector according to  claim 13 , 
 wherein the lens section has an optically operative lens area and a dummy area extended from the lens area toward the outer side of the lens array, and    wherein the dummy area is formed at least on outermost small lenses that are press-molded at the outer periphery of the molding die when press-molded in the molding die.    
   
   
       15 . The projector according to  claim 14 , wherein the dummy area is an area extended from the lens area toward the outer side of the lens array in a range of 0.5 to 2.0 mm.  
   
   
       16 . The projector according to  claim 13 , wherein the lens section is formed in a substantially rectangular shape in plan view with four chamfered corners, and a peripheral edge of the lens section is a slant face that is slanted from the inner side of the lens section toward the outer side to be angled with respect to the one face of the base.  
   
   
       17 . The projector according to  claim 13 , wherein the plurality of small lenses of the lens section are connected with little height difference at a connected part of each other.  
   
   
       18 . The projector according to  claim 13 , 
 wherein the base has a flat section where the thickness of the base is equal, the flat section surrounding an area where the plurality of small lenses are formed, and    wherein a step projected or recessed from the flat section is formed at a position on an end face as the bend-separation face.    
   
   
       19 . A method for manufacturing a lens array including a base with a shape of substantially rectangular plate, and a dome-shaped lens section formed on one face of the base and having a plurality of small lenses, the method comprising: 
 a press-molding step for setting and press-molding a molten optical material in a molding die in which a plurality of dies corresponding to the lens array are formed; and    a bending and separating step for removing from the molding die after the molding, and separating adjacent lens array molded articles by bending at a boundary thereof.    
   
   
       20 . The manufacturing method of the lens array according to  claim 19 , wherein dies corresponding to a plurality of types of lens array different in the optical function are formed in the molding die.  
   
   
       21 . The manufacturing method of the lens array according to  claim 19 , wherein the dies corresponding to 2×(1+n) sets of the lens array are formed in the molding die, and the dies are arranged in a matrix form of 2 rows×(1+n) columns, where n represents a natural number including zero.  
   
   
       22 . The manufacturing method of the lens array according to  claim 21 , wherein the dies arranged in the matrix form of 2 rows×(1+n) columns are symmetric with respect to a plane passing a boundary line of each row.  
   
   
       23 . The manufacturing method of the lens array according to  claim 21 , 
 wherein at least four dies corresponding to the lens array are formed, and    wherein four adjacent dies in said dies are symmetric about an axis passing a cross point of boundary lines of the respective dies, under a 180 degree rotation.    
   
   
       24 . The manufacturing method of the lens array according to  claim 19 , wherein two dies corresponding to the lens array are formed in the molding die, and the dies are symmetric about a rotation axis under a 180-degree rotation, the rotation axis passing the center of a boundary line of each row.