Luminaire for use in backlighting a liquid crystal display matrix
AssigneeRockwell International Corporation
InventorsThomas A. Mepham, Roger D. Eller, Gerald L. Vick
Life of this patent
Estimating the term…
Abstract
A luminaire including one or more fluorescent tubes and associated reflectors for use in backlighting a projection type liquid crystal display matrix. The reflectors have special arcuate shapes designed to forwardly project light to the display matrix and also to direct diffuse light outward from behind the fluorescent tubes so that all of the light generated by the tubes can be efficiently projected for use in illuminating the display matrix.
Claims9
A reflector for use in conjunction with a tubular fluorescent lamp for backlighting a liquid crystal display matrix, comprising:
- a light reflecting surface extending out from the surface of said lamp in an arc approximately defined in two dimensions x and y by the parametric equations:
- x=.rho.cos.phi.
- y=.rho.sin.phi.
- where:
- x=lateral distance from lamp center point perpendicular to the intended direction of light projection,
- y=forward distance from lamp center point parallel to the intended direction of light emission,
- .rho.=radial distance to point (x,y) defined as .rho.=R(1+(.pi.-.theta.).sup.2).sup.1/2,
- .phi.=angle between a horizontal line through lamp center and a line extending from lamp center to point (x,y) where .phi. is defined as
- .phi.=.theta.+tan.sup.-1 (.pi.-.theta.);
- and,
- .theta.=angle between a horizontal line through lamp center point and a second radius extending to the point at which a line perpendicular to the reflective surface at point (x,y) is tangent to the surface of the lamp.
A reflector for use in forwardly projecting and partially collimating light from a fluorescent tube, comprising:
- a first inner section designed to reflect substantially all of the diffuse light emitted from the backside of said tube through a single point laterally outward of said tube and forward of the center of said tube;
- and
- a second outer section having a parabolic shape with respect to said tube which is designed to partially collimate the light emitted by said tube.
A luminaire comprising:
- a fluorescent tube, having a center, a frontside and a backside,
- a first inner reflector section designed to reflect substantially all of the diffuse light emitted from the backside of said tube through a single point laterally outward of said tube and forward of the center of said tube,
- a second outer reflector section having a parabolic shape with respect to said tube which is designed to partially collimate the light emitted by said tube, and
- a liquid crystal matrix disposed forward of the center of said tube, so that said frontside of said tube faces toward said matrix.
A luminaire for use in backlighting a projection type liquid crystal display matrix, comprising:
- a plurality of fluorescent tubes for generating fluorescent light having frontsides facing said matrix and backsides facing away from said matrix,
- a plurality of arcuate reflectors, two of which are associated with each of said tubes and which are shaped to project light toward said matrix and to reflect light emitted from the backsides of said tubes laterally outward and forward from said tubes so that it can also be projected toward said matrix,
- wherein said arcuate reflectors have light reflecting surfaces extending out from said tubes in arcs approximately defined in two dimensions x and y be the parametric equations:
- x=.rho.cos.phi.
- y=.rho.sin.phi.
- where:
- x=lateral distance from lamp center point perpendicular to the intended direction of light projection,
- y=forward distance from lamp center point parallel to the intended direction of light projection,
- .rho.=radial distance to point (x,y), and
- .phi.=angle between a horizontal line through lamp center point and a second radius extending to the point at which a line perpendicular to the reflective surface at point (x,y) is tangent to the surface of the lamp.
A luminaire for use in backlighting a projection type liquid crystal display matrix, comprising:
- a plurality of fluorescent tubes for generating fluorescent light having frontsides facing said matrix and backsides facing away from said matrix,
- a plurality of arcuate reflectors, two of which are associated with each of said tubes and which are shaped to project light toward said matrix and to reflect light emitted from the backsides of said tubes laterally outward and forward from said tubes so that it can also be projected toward said matrix,
- wherein said arcuate reflectors have light reflecting surfaces including:
- an inner section designed to reflect substantially all of the diffuse light emitted from the backside of said tube through a single point laterally outward of said tube and forward of the center of said tube, and
- an outer section having a parabolic shape with respect to said tube which is designed to partially collimate the light emitted by said tube.
Dependencies are inferred from the claim text.