US 5,969,872 A · Spatial light modulator illumination system

Abstract

A novel optical system operative to transfer, with high efficiency, optical power from a line source, such as a LDB, built from a plurality of individual light sources with different angular distribution in two orthogonal axis into a rectangular area with a particular aspect ratio and two different numerical apertures. The near field pattern of a LDB is imaged onto the plane of an SLM. The system utilizes light generated from an LDB having a plurality of individual light sources to illuminate a microlens array. The microlens array, consisting of a plurality of microlenses, functions to collimate the light from the LDB in the slow axis. An optical element adjacent the microlens array refracts the light in the fast axis. In the slow axis, the light from the microlens array is incident upon an optical element which focuses the light onto the SLM plane such that the light from each point light source illuminates the entire active pixel area of the SLM. An additional optical element focuses the light in the fast axis to generate the required spot image. The optical system of the present invention utilizes natural aberrations and/or artificial aberrations to decrease the sensitivity of the optical system to the smile phenomena exhibited by most laser diode bars.

Claims16

Dependent claims

An optical system for uniformly illuminating a target area having a predetermined aspect ratio and two independent numerical apertures in two orthogonal directions with optical power generated by a plurality of linear arrays of individual light sources, wherein each individual light source illuminates substantially the entire target area, said system comprising:

a plurality of microlens arrays, each microlens array comprising a linear array of microlenses, each said microlens array associated with one of said linear array of light sources, each microlens for receiving and redirecting light from one of said individual light sources into a collimated beam of light in the slow axis;
a plurality of first optical elements for receiving and redirecting light from said linear array of light sources into collimated beams of light in a fast axis, each first optical element associated with one of said linear arrays of light sources;
a second optical element optically aligned with said plurality of microlens arrays, said second optical element for receiving light in the slow axis from said plurality of microlens arrays and for focusing light therefrom onto said target area;
and
a third optical element optically aligned with said plurality of first optical elements, said third optical element for receiving light in the fast axis from said plurality of first optical elements and for focusing light therefrom onto said target area.

2 more elements

An optical system for uniformly illuminating a target area having a predetermined aspect ratio and two independent numerical apertures in two orthogonal directions with optical power generated by a first linear array of individual light sources and a second linear array of individual light sources, wherein each individual light source illuminates substantially the entire target area, said system comprising:

a first microlens array and a second microlens array, said first microlens array comprising a first liar array of microlenses, said second microlens array comprising a second linear array of microlenses, said first microlens array associated with said first linear array of light sources, said second microlens array associated with said second linear array of light sources, each microlens for receiving and redirecting light from said individual light sources into a collimated beam of light in the slow axis;
a first optical element and a second optical element for receiving and redirecting light from said first and second linear array of light sources, respectively, into collimated beams of light in a fast axis;
a prism comprising at least two mirrored sides, said prism suitably positioned to closely place together in parallel said collimated beams of light from said first and second optical element;
a third optical element optically aligned with said fist microlens arrays and said second microlens arrays, said second optical element for receiving light in the slow axis from said first microlens array and said second microlens array and for focusing light therefrom both onto said target area;
and
a fourth optical element optically aligned with said first and second optical elements, said fourth optical element for receiving light in the fast axis from said first and second optical elements and for focusing light therefrom onto said target area.

3 more elements

Dependencies are inferred from the claim text.

Spatial light modulator illumination system

Life of this patent

Spatial light modulator illumination system

Life of this patent

Abstract

Claims16