Differential interferometric light modulator and image display device

DETAILED DESCRIPTION An aspect of the invention provides a novel light modulator, a scanner and projection optics as a system for displaying images to an observer.
The system has several desirable features including high contrast and speed.
According to an aspect of the invention a novel light modulator incorporates a polarizing prism to split light beams into components of orthogonal polarization.
These polarization components are made to travel unequal distances in the modulator and are then recombined in the prism.
When one polarization component is phase shifted with respect to the other, the overall polarization of the recombined beam is transformed.
The polarization of the recombined beam is then analyzed by a polarizing beam splitter.
Light intensity output from the polarizing beam splitter depends on the polarization state of the incident light beam which in turn depends on the relative phase shift of the polarization components.
A phase shift is imparted to the orthogonal polarization components in the modulator by focusing them on, and causing them to reflect from, an engineered, uneven surface.
This phase shift surface has regions of slightly different displacement which cause the light beams to travel slightly different distances upon reflection.
More specifically a novel microelectromechanical system (MEMS) ribbon array device is provided that is used to modulate the phase shift of light beams reflected from the surface of its ribbons.
The MEMS ribbon array device has several advantages over conventional devices including the property that a single ribbon in the device represents a single pixel in a line image.
Further, non-active areas of the device do not cause artifacts in a displayed image because they lie at the same surface height.
Features in the device at the same surface height do not cause relative phase shifts in light that reflects from the device and therefore do not appear at the output of the interferometer.
Furthermore, although aspects of the invention are described below primarily in terms of their applicability to image display, they may also be used profitably to perform other functions such as parallel readout of cantilever position in a linear array of atomic force microscope (AFM) cantilevers