Light controlling sheet

• US 4,788,094 A
• Filed: 10/09/1986
• Issued: 11/29/1988
• Est. Priority Date: 09/25/1986
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Original Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Inventors: Morita, Masayuki, Takahashi, Hiroaki, Goto, Masakazu, Takeuchi, Noboru, Kojima, Takeshi
• Primary Examiner(s): Thomas, Alexander S.
• Application Number:
  US06/917,141
• Time in Patent Office: 782 Days
• Field of Search: 428/137, 428/134, 428/913, 428/596, 428/136, 350/370, 350/374, 350/392, 342/4, 335/301, 174/35 MS
• US Class Current: 428/136
• CPC Class Codes: G02B 5/00 Optical elements other than lenses light guides G02B6/00; optical logic elements G02F3/00
• CPC Class Codes: H01J 2229/8905 Direction sensitive devices for controlled viewing angle
• CPC Class Codes: H01J 29/89 Optical or photographic arrangements structurally combined or co-operating with the vessel H01J29/866 and H01J29/868 take precedence
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10T 428/12361 having aperture or cut
• CPC Class Codes: Y10T 428/24314 Slit or elongated
• CPC Class Codes: Y10T 428/24322 Composite web or sheet

Abstract

The disclosure relates to a light controlling sheet for use with indicators which includes a louver element including an arbitrary pattern of walls which are parallel to each other and opaque so as to absorb light, and an electrically conductive film which is mounted on one surface of the louver element. This film is porous so that the light from a light source may penetrate. The oblique light strikes the opaque walls of the louver element and is absorbed in the walls, while the substantially parallel light is permitted to pass through the space or transparent portion betwee the walls. The electrically conductive film not only acts as a protective cover for the louver element but also shields unwanted electromagnetic wave.

Claims

1. A light controlling sheet for use in indicators comprising:

a louver element including an arbitrary pattern of walls having openings therebetween, inner surfaces of said walls defining said openings and extending in a direction of thickness of said louver element, said walls being opaque such that oblique light striking the inner surfaces of said walls may be absorbed by said walls while substantially parallel light may only travel through said openings in a direction which is substantially parallel to said walls; and

an electrically conductive film mounted on one surface of said louver element, said film permitting light to pass through openings therein, said film acting as a protective cover for said louver element and acting to avoid electromagnetic waves.

2. The light controlling sheet as recited in claim 1, wherein said film has a pattern which corresponds to the pattern of said louver element.

3. The light controlling sheet as recited in claim 1, wherein said film is opaque so as to absorb extraneous light.

4. The light controlling sheet as recited in claim 1, wherein said film is a member of a contact for a switch.