Optical: systems and elements – Optical modulator – Light wave temporal modulation
Reexamination Certificate
1999-11-30
2001-11-06
Epps, Georgia (Department: 2873)
Optical: systems and elements
Optical modulator
Light wave temporal modulation
C359S290000, C359S291000, C359S230000, C359S224200
Reexamination Certificate
active
06313937
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to spatial light modulation devices and more specifically to electromagnetic spatial light modulation devices formed by placing a nickel layer upon a substrate and an electromagnet below the nickel layer.
BACKGROUND OF THE INVENTION
Micro-shutters have been used within the prior art as light spatial modulators. One of the more notable of these is U.S. Pat. No. 5,784,189 issued to Bozler et al. and assigned to Massachusetts Institute of Technology (MIT), hereinafter referred to as the Bozler '189 patent. This prior art disclosure taught making spatial light modulators using micro-shutters that were lithographically generated and electrostatically controlled. The individual micro-shutters employed aluminum and required electrostatic control. While useful as teaching a method towards fabricating a light modulation devices with small apertures, the Bozler '189 fails to teach micro-shutter fabrication techniques that are useful under magnetic control.
As shown in U.S. Pat. No. 4,012,828, a Digital Frame Counter is described where the exposures used for a camera are displayed in a digital format. Such a digital frame counter could be a Liquid Crystal Display (LCD). The advantages of this type of display are that individual numbers can be larger than the above discussed rotating wheel, and each frame number can be displayed without resorting to the used of dots as intermediate frame numbers. The disadvantages of this type of display are that LCD's are relatively expensive, require support electronics and can appear dark in low light situations due to their dependence on polarizing filters for them to function.
As seen by the foregoing discussion, it should be readily apparent that there remains a need within the art for a magnetically controlled micro-shutter that is inexpensive to fabricate.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for an electromagnetic spatial light modulation device as formed by placing a soft magnetic layer with a nickel layer upon a substrate and creating an electromagnet below the device. The soft magnetic layer is forced to roll and unroll in response to a magnetic field created by passing an electric current through the conductive traces in the surface of the substrate. The soft magnetic layer is drawn by the electromagnetic field created when a current is introduced into the conductive traces.
This present invention provides a spatial light modulation device comprising a substrate material of one of the following: (glass, quartz, single crystal silicon, ceramic, plastic or a metal) with a series of conductive traces formed in the surface of the substrate, a plurality of photoresist layers with the corrugations being formed in the top photoresist layer away from the substrate wherein the photoresist layer forms a release layer on the substrate that can peel away from the substrate, a pair of nickel layers with a first nickel layer having a compressive stress and a second nickel layer having a tensile stress formed on the release layer. The pair of nickel layers having a thickness of about 500 Angstroms. The method for creating the apparatus envisions providing the nickel layer upon a photoresist layer, the photoresist layer being patterned to created the fixedly attached end of the segment with the remaining portion of the segment being removably attached, a highly resistive film on top of the nickel layers, an electromagnet formed below the photoresist layers as a series of opposite poles created by the series of conductive paths that wind through the substrate once the conductive paths are energized.
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Dowe David R.
Furlani Edward P.
Reznik Svetlana
Eastman Kodak Company
Epps Georgia
Lucas Michael A.
Watkins Peyton C.
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