Directional optical filter
First Claim
1. Filter for selectively admitting radiant energy to pass therethrough including at least one radiant energy transmitting media having first and second sides, and a surface of the media on the first side, wherein an image on one side of the media can be viewed from the other side, characterized by:
- said surface being interrupted by a plurality of light-absorbing grooves, the plurality of grooves extending from said surface, extending less than completely through the media and arranged in a pattern, the grooves having a characteristic of absorbing said radiant energy impinging thereon from within the media, such that radiant energy passing said surface from a pre-determined angle from normal to said surface is substantially absorbed and radiant energy passing said surface from less than said pre-determined angle and not impinging upon the grooves is transmitted in accordance with radiant energy transmitting characteristics of said media for that energy.
2 Assignments
0 Petitions
Accused Products
Abstract
A directional filter is constructed with a plurality of grooves (15) extending into a plate (13) from one side (16) thereof. The grooves (15) have a light absorbing characteristic which causes them to absorb light impinging upon the grooves, particularly light impinging upon the grooves (15) from within the plate (13). Since all light passing beyond a certain angle φ must impinge upon the grooves (13), and only a small percentage of light passing parallel to the cut of the grooves (15) would impinge upon the grooves (15), the filter has a high ratio of attenuation of unwanted versus wanted light.
135 Citations
17 Claims
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1. Filter for selectively admitting radiant energy to pass therethrough including at least one radiant energy transmitting media having first and second sides, and a surface of the media on the first side, wherein an image on one side of the media can be viewed from the other side, characterized by:
said surface being interrupted by a plurality of light-absorbing grooves, the plurality of grooves extending from said surface, extending less than completely through the media and arranged in a pattern, the grooves having a characteristic of absorbing said radiant energy impinging thereon from within the media, such that radiant energy passing said surface from a pre-determined angle from normal to said surface is substantially absorbed and radiant energy passing said surface from less than said pre-determined angle and not impinging upon the grooves is transmitted in accordance with radiant energy transmitting characteristics of said media for that energy. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A video display including a cathode ray tube and a filter for selectively admitting radiant energy to pass therethrough, the filter including at least one radiant energy transmitting media having first and second sides and a surface of the media on the first side wherein an image on one side of the media can be viewed from the other side, characterized by:
said surface being interrupted by a plurality of light-absorbing grooves which are cut into said surface so as to extend less than completely through the media, the plurality of grooves extending from said surface and arranged in a pattern, the grooves having a characteristic of absorbing said radiant energy impinging thereon from within the media, such that radiant energy passing said surface from pre-determined angle from normal to said surface is substantially absorbed and radiant energy passing said surface form less than said pre-determined angle and not impinging upon the grooves is transmitted in accordance with radiant energy transmitting characteristics of said media for that energy.
Specification