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US 5,398,125 AGranted
Liquid crystal projection panel having microlens arrays, on each side of the liquid crystal, with a focus beyond the liquid crystal
AssigneeMinnesota Mining and Manufacturing Company
InventorsStephen J. Willett, David J. W. Aastuen
Life of this patent
Estimating the term…
Abstract
A liquid crystal projection panel for use in a projection system. The projection panel is comprised of a large number of pixels of liquid crystal defining a image forming plane provided between two transparent substrates. Microlens arrays are provided on both sides of the projection panel. The microlenses in both arrays have focal lengths such that parallel light rays entering the microlenses at an angle perpendicular to the arrays are focused at points beyond the image forming plane of the display.
Claims10
A pixellated display projection panel, comprising:
- a pixellated display comprised of a plurality of pixels providing an image forming plane between two optically transparent substrates;
- a first microlens array provided on one side of the display, the microlenses in the array corresponding to the pixels in the display, wherein the microlenses have focal lengths such that parallel light rays from a first direction entering the microlenses at an angle perpendicular to the first array are focused at points beyond the image forming plane of the display;
- and
- a second microlens array provided on the other side of the display, the microlenses in the array corresponding to the pixels in the display, wherein the microlenses have focal lengths such that parallel light rays from a direction opposite said first direction entering the microlenses at an angle perpendicular to the second array are focused at points beyond the image forming plane of the display.
1 more element
A pixellated display projection system, comprising:
- a pixellated display comprised of a plurality of pixels provided an image forming plane between two optically transparent substrates;
- a first microlens array provided on one side of the display, the microlenses in the array corresponding to the pixels in the display, wherein the microlenses have focal lengths such that parallel light rays from a first direction entering the microlenses at an angle perpendicular to the first array are focused at points beyond the image forming plane of the display;
- a second microlens array provided on the other side of the display, the microlenses in the array corresponding to the pixels in the display, wherein the microlenses have focal lengths such that parallel light rays from a direction opposite said first direction entering the microlenses at an angle perpendicular to the second array are focused at points beyond the image forming plane of the display;
- a light source emitting light rays toward the display;
- and
- means for projecting light rays exiting the second microlens array toward a viewing screen.
3 more elements
A method of making a pixellated display projection panel, comprising:
- providing a pixellated display comprised of a plurality of pixels providing an image forming plane between two optically transparent substrates, wherein the thicknesses of the substrates vary within a known range around an average value;
- providing a first microlens array provided on one side of the display, the microlenses in the array corresponding to the pixels in the display, wherein the microlenses have focal lengths such that parallel light rays from a first direction entering the microlenses at an angle perpendicular to the first array are focused at points beyond the image forming plane of the display;
- providing a second microlens array provided on the other side of the display, the microlenses in the array corresponding to the pixels in the display, wherein the microlenses have focal lengths such that parallel light rays from a direction opposite said first direction entering the microlenses at an angle perpendicular to the second array are focused at points beyond the image forming plane of the display;
- and
- selecting the optimum radius of curvature for the microlenses in the arrays based on the upper end of the range of thicknesses of the substrates.
2 more elements
Dependencies are inferred from the claim text.