JP2007248675A - Substrate for plastic fresnel lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for a plastic Fresnel lens which is hard to warp even made thin without causing uneven brightness and irregular images and not degrading workability when machining the lens. <P>SOLUTION: The substrate for the Fresnel lens is a sheet made of a synthetic resin 0.1-1.0 mm thick and folded at least on one side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a synthetic resin Fresnel lens substrate used in a rear projection display.

  A rear projection display generally uses a screen composed of a lenticular lens and a Fresnel lens, and an image is projected onto the screen. As the Fresnel lens, a lens processed with a synthetic resin sheet having a thickness of about 2 mm is used.

  In response to the demands for thinner and lighter displays, synthetic resin sheets used as Fresnel lenses are also desired to be thinner. However, if a synthetic resin sheet is made thin, the rigidity of the sheet is lowered and bending occurs, the distance between the lenticular lens and the Fresnel lens becomes unstable, and inconveniences such as brightness unevenness and image unevenness occur, or the lens. There exists a problem that workability | operativity of a process falls.

  The present invention solves the above-mentioned problem and does not cause bending even when the thickness is reduced. Therefore, there is no inconvenience such as brightness and unevenness of image, and the synthetic resin Fresnel lens does not reduce workability during lens processing. An object of the present invention is to provide a circuit board.

  The present inventor has found that the above problem can be solved by forming a bent end portion of a synthetic resin sheet used as a substrate for a Fresnel lens. That is, the present invention relates to a Fresnel lens substrate used in a rear projection display, wherein the thickness is 0.1 to 1.0 mm and at least one side is bent. The gist of the substrate for Fresnel lenses.

  As described above, the substrate for the Fresnel lens of the present invention has a thickness of 0.1 to 1.0 mm, and has a shape in which at least one side is bent. In addition, there is no inconvenience such as image unevenness, and there is no reduction in workability at the time of lens processing, and it is possible to meet the demand for a thin and light weight rear projection display.

  As the synthetic resin used for the synthetic resin Fresnel lens substrate of the present invention, polymethyl methacrylate, acrylic resins such as styrene / methyl acrylate copolymer, polystyrene, polycarbonate resin, polyester resin and the like are used.

  As the polycarbonate resin, a sheet made of an aromatic polycarbonate having a bisphenol skeleton is usually used. In addition, an aromatic polycarbonate resin copolymer, and further, a polycarbonate resin or a resin obtained by blending another transparent resin and a polyester resin with the copolymer resin. It is also possible to use a sheet or the like.

  The polyester resin is a polymer obtained by condensation polymerization from dicarboxylic acid and diol, and the dicarboxylic acid is represented by terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid, etc. The diol is represented by ethylene glycol, trimethylene glycol, tetramethylene glycol, cyclohexanedimethanol, polyalkylene glycol, bisphenol A ethylene oxide adduct, and the like. Specific polyester resins include polymethylene terephthalate, polyethylene terephthalate, polytetramethylene terephthalate, polyethylene-p-oxybenzoate, poly-1,4-cyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalate and the like. I can do it. Of course, these polyesters may be homopolymers or copolymers, and examples of the copolymer component include diol components such as diethylene glycol, neopentyl glycol, polyalkylene glycol, and bisphenol A ethylene oxide adduct, Dicarboxylic acid components such as dimer acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are used.

  Additives such as flame retardants, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, and diffusing agents can also be added to polycarbonate resins and polyester resins.

  As the polycarbonate resin and polyester resin sheet, those subjected to ultraviolet (UV) treatment, plasma treatment, antistatic treatment, hard coat treatment, emboss treatment, etc. can be used.

  The Fresnel lens substrate of the present invention is formed into a sheet shape by extrusion molding or the like of the above polycarbonate resin, and the obtained sheet is bent or injected using a mold corresponding to the bent shape. By molding, it is used for a Fresnel lens.

  The thickness of the substrate of the present invention is 0.1 to 1.0 mm. If the thickness is less than 0.1 mm, the sheet is not suitable because the rigidity is insufficient even if the sheet is folded. If the thickness is greater than 1.0 mm, the demand for thin and light display cannot be met.

  The bending is performed by, for example, a method in which a flat plate is heated without using a male / female press die with a press pressure, two sides are supported by a female die using a press brake, and an arbitrary angle is determined depending on the insertion depth of the male die. It is made by a method of bending, a method of bending continuously by roll forming, or the like. Or the material temperature of the part to be bent can be 150-200 degreeC using a pipe heater or a slit heater, and it can also be bent using the jig | tool of a predetermined angle. There are no particular restrictions on the folding width, folding angle, or folding shape at the time of folding, but the folding workability, the structure of a rear projection display using a Fresnel lens, or the required degree of rigidity, etc. It is decided as appropriate in consideration.

  A lens pattern of the Fresnel lens is formed on at least one side of the Fresnel lens substrate thus obtained by a method using an ultraviolet curable resin or the like, and is used as a screen of a rear projection display.

  Insoluble acrylic polymer fine particles (trade name: Chemisnow MX-1000), which are transparent fine particles, per 100 parts by weight of a polycarbonate resin having a viscosity average molecular weight of 27,000 (trade name: Caliber 303-4, manufactured by Sumitomo Dow). 5 parts by weight) (manufactured by Soken Chemical Co., Ltd.) were weighed and mixed with a tumbler to obtain a sheet having a thickness of 0.5 mm with a 40 mmφ extruder.

  The obtained sheet was cut into a square having a length of 300 mm, and was folded at an angle of 90 ° C. with a folding width of 5 mm on two opposite sides of the sheet of this size. The bending was observed when a flat plate before the bending process and one side of the folded sheet were placed on a horizontal table. At this time, one side (5 cm width) of the sheet was placed on a horizontal table, and the amount of deflection of the sheet protruding from the horizontal table was measured. As a result, the flat plate not bent was bent by 55 mm from the horizontal plane, and the bent sheet was bent by 10 mm.

Claims (1)

  A synthetic resin Fresnel lens substrate having a thickness of 0.1 to 1.0 mm and at least one side bent in a substrate for a Fresnel lens used in a rear projection display.