Direct filament lamp assembly

Claim 2

In a direct filament lamp assembly having a lens including optical means which increasingly vertically refract emitted light at the longer focal distances resulting in a deviation from a desired illuminatioN pattern, the improvement comprising: optical means in the form of continuous warped light refracting flutes formed in parallel spaced relationship on the inner surface of the lens, each of said flutes having an incrementally differing angular position along the length thereof with respect to the filament and the outer surface of the lens so as to incrementally compensate for changing focal distances and angular positions of said outer surface thereby correcting said deviation and predictably distributing said emitted light from the lens in said desired illumination pattern.

Claim 3

In a direct filament lamp assembly having a housing and a light source including a filament mounted relative to the housing, a lens for uniformly distributing light rays from the filament in a predetermined intensity pattern, comprising: an optically transmissive window adapted to be positioned against the housing parallel to the filament; spaced rows of continuous refracting prisms formed on said window and extending individually across said window, each of said prisms having a linearly warped contour providing an incremental angular prism position with respect to the filament and the window, said incremental angular prism position compensating for the constantly changing focal distances therebetween and the constantly changing angles between emerging light rays and surface normals along the length of the prism such that light rays are refracted through the window for emergence in said predetermined intensity pattern substantially throughout the extent of said window.

Claim 4

In a direct filament lamp assembly having a housing and a light source including a filament mounted relative to the housing, a lens for uniformly distributing light rays from the filament in a predetermined intensity pattern, comprising: an optically transmissive window adapted to be positioned against the housing parallel to the filament; spaced rows of continuous refracting prisms formed on said window and extending individually across said window, each of said prisms having a linearly warped contour providing an incremental angular prism position with respect to the filament and the window, said incremental angular prism position compensating for the constantly changing focal distances therebetween and the constantly changing angles between emerging light rays and surface normals along the length of the prism such that light rays are refracted through the window for emergence in said predetermined intensity pattern substantially throughout the extent of said window.

Claim 5

A direct filament lamp assembly comprising: a housing; a light source having a filament with an axis mounted horizontally relative to the housing; and a lens for predictably uniformly horizontally distributing illumination from the filament in a predetermined intensity pattern, said lens having a planar optically transmissive body adapted to be positioned with respect to the housing with an outer surface generally parallel to the axis of the filament, and a plurality of equally spaced continuous horizontal prisms formed on the inner surface of the optically transmissive body and extending individually thereacross parallel to the axis of the filament, each of said prisms having a linearly warped contour which presents an incrementally differing inclination with respect to the filament and the body, said incrementally differing inclination compensating for changing focal distances and the angles between light rays entering the prism and normals to said outer surface such that light is refracted through the body for emergence in accordance with the position of the prisms in the window and the pattern sector the prisms are intended to illuminate.

Claim 6

A direct filament lamp assembly comprising: a housing; a light source having a filament with an axis mounted horizontally relative to the housing; and a lens for predictably uniformly horizontally distributing illumination from the filament in a predetermined intensity pattern, said lens having a planar optically transmissive body adapted to be positioned with respect to the housing with an outer surface generally parallel to the axis of the filament, and a plurality of equally spaced continuous horizontal prisms formed on the inner surface of the optically transmissive body and extending individually thereacross parallel to the axis of the filament, each of said prisms having a linearly warped contour which presents an incrementally differing inclination with respect to the filament and the body, said incrementally differing inclination compensating for changing focal distances and the angles between light rays entering the prism and normals to said outer surface such that light is refracted through the body for emergence in accordance with the position of the prisms in the window and the pattern sector the prisms are intended to illuminate.