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US 6,461,000 B1Granted
Optical systems for projection displays
AssigneeU.S. Precision Lens Incorporated
InventorSimon Magarill
Life of this patent
Estimating the term…
Abstract
A prism (13) for use in a projection system which employs a digital light panel (35) is provided. The prism includes first (19) and second (21) spaced part surfaces which are oriented such that: (a) light from a light source (33) will pass through the spaced apart surfaces to the digital light panel; (b) light from “on” pixels will undergo total internal reflection at the second surface (21) and be directed into the acceptance angle of a projection lens (39); and (c) light from “off” pixels which reflects from the second surface will be directed away from the lens' acceptance angle.
Claims4
In an image projection system comprising:
- (a) a light source which provides illuminating light;
- (b) a plurality of selectively adjustable reflecting elements which are arranged in a common plane, said elements being adjustable between at least a first position and a second position;
- (c) a lens having a principal plane which is parallel to said common plane;
- and
- (d) a prism positioned between said lens and said plurality of reflecting elements;
- the improvement wherein:
- (A) the lens has an acceptance angle;
- (B) the prism comprises first and second spaced apart surfaces that are oriented relative to the light source, the plurality of reflecting elements, and the lens such that:
- (i) light from the light source passes through the first and second spaced apart surfaces to the plurality of reflecting elements, and
- (ii) light reflected from reflecting elements in the first position (a) passes through a first reflected-light transmitting side of the prism, (b) is reflected at the second spaced apart surface in directions which are within the lens' acceptance angle, and (c) passes through a second reflected-light transmitting side of the prism;
- (C) the system has an image side optical axis which is:
- (i) perpendicular to the common plane;
- and
- (ii) undergoes a change in direction at the second spaced apart surface;
- (D) the principal plane is parallel to the common plane when translated along the image side optical axis and reflected from the second spaced apart surface;
- and
- (E) the first and second reflected-light transmitting sides of the prism have an internal angle of intersection that is acute.
14 more elements
In an image projection system comprising:
- (a) a light source which provides illuminating light;
- (b) a plurality of selectively adjustable reflecting elements which are arranged in a common plane, said elements being adjustable between at least a first position and a second position;
- (c) a lens having a principal plane which is parallel to said common plane;
- and
- (d) a prism positioned between said lens and said plurality of reflecting elements;
- the improvement wherein:
- (A) the lens has an acceptance angle;
- (B) the prism comprises first and second spaced apart surfaces that are oriented relative to the light source, the plurality of reflecting elements, and the lens such that:
- (i) light from the light source passes through the first and second spaced apart surfaces to the plurality of reflecting elements, and
- (ii) light reflected from reflecting elements in the first position is reflected at the second spaced apart surface in directions which are within the lens' acceptance angle;
- (C) the system has an image side optical axis which is:
- (i) perpendicular to the common plane;
- and
- (ii) undergoes a change in direction at the second spaced apart surface;
- (D) the principal plane is parallel to the common plane when translated along the image side optical axis and reflected from the second spaced apart surface;
- (E) the first spaced apart surface is associated with a first component of the prism through which light from the light source passes but light reflected from the reflecting elements in the first position does not pass;
- (F) the second spaced apart surface is associated with a second component of the prism through which both light from the light source and light reflected from the reflecting elements in the first position passes;
- and
- (G) the first component has a lower optical quality than the second component.
16 more elements
In an image projection system comprising:
- (a) a light source which provides illuminating light;
- (b) a plurality of selectively adjustable reflecting elements which are arranged in a common plane, said elements being adjustable between at least a first position and a second position;
- (c) a lens having a principal plane which is parallel to said common plane;
- and
- (d) a prism positioned between said lens and said plurality of reflecting elements;
- the improvement wherein:
- (A) the lens has an acceptance angle;
- (B) the prism comprises first and second spaced apart surfaces that are oriented relative to the light source, the plurality of reflecting elements, and the lens such that:
- (i) light from the light source passes through the first and second spaced apart surfaces to the plurality of reflecting elements, and
- (ii) light reflected from reflecting elements in the first position is reflected at the second spaced apart surface in directions which are within the lens' acceptance angle;
- (C) the system has an image side optical axis which is:
- (i) perpendicular to the common plane;
- and
- (ii) undergoes a change in direction at the second spaced apart surface;
- (D) the principal plane is parallel to the common plane when translated along the image side optical axis and reflected from the second spaced apart surface;
- (E) light reflected from some reflecting elements in the second position is reflected at the second spaced apart surface in directions which are not within the lens' acceptance angle;
- (F) light reflected from other reflecting elements in the second position passes through the second spaced apart surface;
- (G) the first spaced apart surface is associated with a first component of the prism through which light from the light source passes but light reflected from the reflecting elements in the first position does not pass;
- (H) the second spaced apart surface is associated with a second component of the prism through which both light from the light source and light reflected from the reflecting elements in the first position passes;
- and
- (I) the first component has a lower optical quality than the second component.
18 more elements
Dependencies are inferred from the claim text.