EP0149150A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Low moire directional optical filter for crt displays
Assignee: Honeywell International Inc
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Filing: 1984-12-13
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Granted: —
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Expires: 2004-12-13
Abstract
Abstract A directional optical filter (41) is provided for a shadow mask color cathode ray tube (shadow mask CRT) (47) having a plurality of display elements on its face (49). Two sets of light absorbing planes are arranged at approximately 90° from one another and serve to block light passing therethrough from an angle greater than a predetermined angle of viewing. in order to reduce moire patterns which would result from varying coincidences of the planes with patterns of phosphor dots on the shadow mask CRT (47), filter sheets (43, 45) containing the light absorbing planes are rotated so that at least one set of light absorbing planes is misaligned with a set of closely-adjacent phosphor dots by approximately 15°. Advantages include the ability to provide a parallel light absorbing plane directional optical filter in association with a shadow mask CRT and an ability to control the range of preferred viewing angles to differing amounts substantially in the horizontal and vertical directions.
Inventors
- 👤 Richard Lawrence Cohen
- 👤 John Wilson
- 👤 Mitchell Aron
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 01:27
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/86; H01J29/89; H01J2229/00; H01J2229/89; H01J2229/8905
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
139 words
Directional optical filter (41), for use with a display (49) having a plurality of display elements (13) which are in a regular pattern and which are selectively illuminated in order to provide display patterns, some of which elements (13) have similar features, characterized in that: a) a plurality of planes (31, 33), which are substantially light absorbing, are disposed at a preferred viewing angle with respect to the display (49); b) the light absorbing planes (31, 33) are disposed in at least one set (43 or 45), in which the planes (31) in said set are substantially parallel to one another; and c) each set (43), when viewed from the preferred viewing angle, is aligned so that the substantially parallel planes (31) are misaligned approximately 15° from lines (23) passing through the most closely aligned elements having similar features.
Claim 2
Dependent Claim
139 words
Directional optical filter (41), for use with a display (49) having a plurality of display elements (13) which are in a regular pattern and which are selectively illuminated in order to provide display patterns, some of which elements (13) have similar features, characterized in that: a) a plurality of planes (31, 33), which are substantially light absorbing, are disposed at a preferred viewing angle with respect to the display (49); b) the light absorbing planes (31, 33) are disposed in at least one set (43 or 45), in which the planes (31) in said set are substantially parallel to one another; and c) each set (43), when viewed from the preferred viewing angle, is aligned so that the substantially parallel planes (31) are misaligned approximately 15° from lines (23) passing through the most closely aligned elements having similar features.
Claim 3
Dependent Claim
126 words
Directional optical filter (41) for use with a shadow mask cathode ray tube (47), having a display element (13) pattern thereon, some of which elements (13) have similar features, characterized in that: a) a plurality of planes (31, 33), which are substantially light absorbing, are disposed at a preferred viewing angle with respect to the display; b) the light absorbing planes (31, 33) are disposed at least one set ( 43 ), in which the planes (31) in said set are substantially parallel to one another; and c) each set (43), when viewed from the preferred viewing angle, is aligned so that the substantially parallel planes (31) are misaligned approximately 15 0 from lines (23) passing through the most closely aligned elements (13) having similar features.
Claim 4
Dependent Claim
126 words
Directional optical filter (41) for use with a shadow mask cathode ray tube (47), having a display element (13) pattern thereon, some of which elements (13) have similar features, characterized in that: a) a plurality of planes (31, 33), which are substantially light absorbing, are disposed at a preferred viewing angle with respect to the display; b) the light absorbing planes (31, 33) are disposed at least one set ( 43 ), in which the planes (31) in said set are substantially parallel to one another; and c) each set (43), when viewed from the preferred viewing angle, is aligned so that the substantially parallel planes (31) are misaligned approximately 15 0 from lines (23) passing through the most closely aligned elements (13) having similar features.
Claim 5
Dependent Claim
35 words
Apparatus as described in Claim 1 or 2, further characterized in that: at least two sets of planes (43, 45) are provided and said two sets (43, 45) are disposed approximately orthogonally to each other.
Claim 6
Dependent Claim
30 words
Apparatus as described in Claims 1, 2 or 3, further characterized in that: the misalignment of each set (43, 45) deviates from the 15 0 misalignment by a small amount.
Claim 7
Dependent Claim
16 words
Apparatus as described in Claim 4, further characterized in that: said small amount is approximately 3°.
Claim 8
Dependent Claim
20 words
Apparatus as described in Claims 1 or 2, further characterized in that: said misalignment may vary by up to 6°.
Claim 9
Dependent Claim
18 words
Apparatus as described in Claims 1 or 2, further characterized in that: said misalignment may vary by 3°.
References Cited (Backward Citations)
No citation records indexed.
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