Title:
METHOD OF MANUFACTURING SHEET-SHAPED PLASTIC PRODUCT WITH SURFACE PROJECTIONS
Document Type and Number:
WIPO Patent Application WO/2000/007793
Kind Code:
A1
Abstract:
A method of manufacturing a diffusion plate used for a screen plate of a projection television, wherein a diffusion plate having substantially over one side surface thereof a multiplicity of projections in the form of quadrangular pyramid is manufactured by injection molding of a plastic material. The method using a first molding die having a first die surface for molding, a preforming die capable of forming a mold cavity of a first volume while being put together with the first molding die, and a second molding die capable of forming a mold cavity of a second volume smaller than the first volume while being put together with the first molding die; and comprising the steps of injecting a molten plastic material into the mold cavity of the first volume between the first molding die and the preforming die from an injection port while the first molding die and the preforming die are put together, after completion of injection and before curing of the plastic material, separating the first molding die from the preforming die and putting it together with the second molding die to effect a second process, and compressing the plastic material, which has been injected in the first process, in the mold cavity of the second volume to mold the plastic material between the first die surface and a second die surface.
Inventors:
HIROTA KASHICHI (JP)
FUKUDA JUNJI (JP)
FUKUDA JUNJI (JP)
Application Number:
PCT/JP1998/003507
Publication Date:
February 17, 2000
Filing Date:
August 06, 1998
Export Citation:
Assignee:
KYOWA ELECTRIC & CHEMICAL (JP)
HIROTA KASHICHI (JP)
FUKUDA JUNJI (JP)
HIROTA KASHICHI (JP)
FUKUDA JUNJI (JP)
International Classes:
G02B5/02; B29C33/42; B29C39/10; B29C43/02; B29C43/14; B29C43/36; B29C45/00; B29C45/10; B29C45/40; B29C45/56; B29C45/57; B29C45/70; G02B3/08; G03B21/60; B29K101/12; B29L11/00; (IPC1-7): B29C45/10; B29C43/02; B29C43/34
Foreign References:
| JPH10249898A | 1998-09-22 | |||
| JPH06114860A | 1994-04-26 | |||
| JPH05173253A | 1993-07-13 | |||
| JPH0298416A | 1990-04-10 | |||
| JPS6031930A | 1985-02-18 | |||
| JPH0185010U | 1989-06-06 | |||
| JPS5967008A | 1984-04-16 |
Attorney, Agent or Firm:
Nakamura, Minoru (Marunouchi 3-chome Chiyoda-ku Tokyo, JP)
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