US 2003/0210380 A1Published application

Image enhancement and aberration corrections in a small real image projection system

AssigneeOptical Products Development Corp.

InventorsKenneth S. Westort, Douglas L. Robinson

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Abstract

An improved real image projection system comprises, in the primary configuration, a tilted mirror to eliminate ghost reflections, and a unique arrangement allowing the introduction of a second background image without a 50%/50% beamsplitter, while providing system transmission of approximately 50%. A secondary configuration incorporates an elliptical or aspheric curved mirror designed to simulate the surface of a spherical curve when light strikes the elliptical surface at an angle equal to the elliptical angle of the curved mirror. In a third configuration, a single curved mirror has two different optical surfaces of revolution, one on the convex surface and one on the concave surface. The concave surface is much like that of a Mangin lens, but it has an aspheric surface of revolution, optimized to reduce spherical aberrations over a larger area offset from the optical axis.

Claims27

Dependent claims

A real image projection system, comprising:

a) a curved mirror, mounted with an optical axis of said curved mirror at a tilted angle, relative to an imaging axis of said image projection system;
b) a target object positioned below said curved mirror, facing toward a front of said image projection system, wherein said target object is selected from the group consisting of a real object, a monitor, a graphic image, a video image, and any object that reflects, transmits, or emits light;
c) a flat fold mirror or reflector positioned below a viewing window of said image projection system, wherein a reflective surface of said flat fold mirror or reflector faces toward said curved mirror and toward said target object, said flat fold mirror or reflector being positioned at an angle such that a target beampath is reflected at a complimentary angle from said target object to said fold mirror to said curved mirror, striking a center or vertex of said curved mirror at an angle equal to twice the angle of tilt of said curved mirror relative to said imaging axis;
and
d) a neutral density window or circular polarizer window positioned along said imaging axis of said system, wherein said neutral density filter comprises a neutral density material or a neutral density coating, and wherein light transmitting through said filter is partially absorbed in near equal amounts across the visible light spectrum.

2 more elements

A real image projection system, comprising:

a) a curved mirror of elliptical or aspheric surface of revolution, mounted with an optical axis of said mirror at a tilted angle of between 12 and 18 degrees, relative to a target axis of said imaging system from between a target object and a center of said curved mirror, positioned overhead with a front edge of said curved mirror nearest a window aperture positioned lower than a rear edge of said curved mirror;
b) a beamsplitter positioned at a 45 degree angle to an axis of said curved mirror and at an angle equal to 45 degrees plus said tilt angle of said curved mirror relative to said target axis of said imaging system, mounted with a top of said beamsplitter positioned nearest a rear edge of said curved mirror, and a bottom edge of said beamsplitter positioned directly beneath said window viewing aperture;
c) a target object positioned at a point along an optical target axis of said imaging system or along an axis offset by said angle of tilt of said curved mirror, with said target axis vertical from said target to a center of said curved mirror, wherein said target object is selected from the group consisting of a real object, a monitor, a graphic image, a video image, and any object that reflects, transmits, or emits light;
d) a window positioned between said beamsplitter and a real image formed by said system, wherein said window is selected from the group consisting of a neutral density substrate, a circular polarizer, or tinted glass;
and
e) a real image formed outside said system along said imaging axis.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/388,062Filed 13 Mar 2003
Priority: 27 Apr 1999
Published: 13 Nov 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G07F 9/02
Details other than those peculiar to special kinds or types of apparatus: devices for alarm or indication, e.g. when empty; Advertising…
G02B 17/08
Systems with reflecting surfaces, with or without refracting elements: catadioptric systems
G02B 17/0856
Catadioptric systems: comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors
G02B 27/0018
Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00: with means for preventing ghost images

Family

Application60/131,320Us provisional application · filed 27 Apr 1999
Application09/557,859Continuation in part · filed 26 Apr 2000
Application09/946,183Continuation in part · filed 5 Sep 2001
Application10/350,762Continuation in part · filed 24 Jan 2003
Application10/388,062Continuation in part · filed 13 Mar 2003
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From the US filing history. Foreign family members aren’t listed.