Light masking device

Claim 2

A light masking device for improving image contrast on a video display screen under conditions of high ambient light, comprising a support frame adapted to be positioned in front of the screen and an optical filter supported thereby, the optical filter comprising a grating of spaced, elongated planar slats extending horizontally across the width of the screen, the slats being differentially inclined from the horizontal in the directions of their widths so as to converge on a horizontal line at a selected height and a selected distance from the screen, wherein the slats are pivotally connected to the support frame for pivotal movement about respective horizontal axes, the device further comprising linkage means interconnected with the slats for differentially adjusting the inclinations of the slats for selectively adjusting the position of said horizontal line on which the inclined slats converge.

Claim 3

A light masking device according to claim 1, wherein the slats are supported under tension in the direction of their length.

Claim 4

A light masking device according to claim 2, wherein the slats are of stainless steel and have substantially non-reflecting surfaces.

Claim 5

A light masking device according to claim 1, wherein said linkage means comprises a parallel linkage mechanism having a pair of upright links and a pair of end links extending transversely to the slats, and a plurality of differentially inclined bearing members extending between said upright links, each slat bearing on a respective one of said bearing members and being constrained thereby to lie in a plane determined by the inclination of said bearing member, said end links being mounted for pivotal movement about respective horizontal axes for differentially adjusting the inclinations of said bearing members with respect to the horizontal.

Claim 6

A light masking device according to claim 1, wherein said linkage means comprises a parallel linkage mechanism having a pair of upright links and a pair of end links extending transversely to the slats, and a plurality of differentially inclined bearing members extending between said upright links, each slat bearing on a respective one of said bearing members and being constrained thereby to lie in a plane determined by the inclination of said bearing member, said end links being mounted for pivotal movement about a common vertical axis for varying the angle at which the bearing members traverse the slats.

Claim 7

A light masking device for improving image contrast on a video display screen under conditions of high ambient light, comprising: a rectangular support frame adapted to be positioned in front of the screen, the support frame comprising a pair of upright end members and a pair of upper and lower cross members, an optical filter supported by the support frame, the optical filter comprising a grating of spaced, elongated planar slats extending horizontally across the width of the frame, the slats being pivotally connected at their ends to said upright frame members for pivotal movement about respective horizontal axes, the slats being differentially inclined from the horizontal in the directions of their widths so as to converge on a horizontal line at a selected height and a selected distance from the frame, and adjustment means interconnected with the slats for differentially adjusting the inclinations of the slats for selectively adjusting the position of said horizontal line on which the inclined slats converge.

Claim 8

A light masking device for improving image contrast on a video display screen under conditions of high ambient light, comprising: a rectangular support frame adapted to be positioned in front of the screen, the support frame comprising a pair of upright end members and a pair of upper and lower cross members, an optical filter supported by the support frame, the optical filter comprising a grating of spaced, elongated planar slats extending horizontally across the width of the frame, the slats being pivotally connected at their ends to said upright frame members for pivotal movement about respective horizontal axes, the slats being differentially inclined from the horizontal in the directions of their widths so as to converge on a horizontal line at a selected height and a selected distance from the frame, and adjustment means interconnected with the slats for differentially adjusting the inclinations of the slats for selectively adjusting the position of said horizontal line on which the inclined slats converge.

Claim 9

A light masking device according to claim 6, wherein said adjustment means comprises: a pair of complementary parallel linkage mechanisms mounted on the support frame adjacent the ends thereof, coupling means interconnecting said mechanisms and constraining said mechanisms for movement in unison, each parallel linkage mechanism comprising a pair of upright links and a pair of end links extending transversely to the slats, and a plurality of differentially inclined bearing links extending between said upright links, each slat bearing on a respective one of said bearing links of each parallel linkage mechanism and being constrained thereby to lie in a plane determined by the inclination thereof, said end links of each parallel linkage mechanism being mounted for pivotal movement about respective horizontal axes for differentially adjusting the inclinations of said bearing links with respect to the horizontal, and said end links of each parallel linkage mechanism being mounted for pivotal movement about a common vertical axis for selectively varying the angle at which the bearing links traverse the slats.

Claim 10

A light masking device according to claim 7, wherein the slats are supported under tension in the direction of their length.

Claim 11

A light masking device according to claim 8, wherein the slats are of stainless steel and have substantially non-reflecting surfaces.

Claim 12

A light masking device according to claim 7, wherein said adjustment means further comprises a first electric motor and a second electric motor mounted on the support, and first and second transmission means interconnecting said motors with said parallel linkage mechanisms for pivotally moving said mechanisms with respect to said horizontal and vertical pivotal axes, respectively.

Claim 13

A light masking device comprising a support frame defining an aperture and an optical filter supported thereby to intercept light falling on said aperture, the optical filter comprising a grating of spaced, elongated planar slats extending parallel to one another across the width of the aperture, the slats being differentially inclined in the directions of their widths so as to converge on a line extending parallel to the slats at a selected distance therefrom, wherein the slats are pivotally connected to the support frame for pivotal movement about respective longitudinal axes, the device further comprising linkage means interconnected with the slats for differentially adjusting the inclinations of the slats for selectively adjusting the position of said line on which the inclined slats converge.

Claim 14

A light masking device comprising a support frame defining an aperture and an optical filter supported thereby to intercept light falling on said aperture, the optical filter comprising a grating of spaced, elongated planar slats extending parallel to one another across the width of the aperture, the slats being differentially inclined in the directions of their widths so as to converge on a line extending parallel to the slats at a selected distance therefrom, wherein the slats are pivotally connected to the support frame for pivotal movement about respective longitudinal axes, the device further comprising linkage means interconnected with the slats for differentially adjusting the inclinations of the slats for selectively adjusting the position of said line on which the inclined slats converge.