Abstract: Methods of characterizing a mechanical stress level in a stressed layer of a transistor and a mechanical stress characterizing test structure are disclosed. In one embodiment, the test structure includes a first test transistor including a first stress level; and at least one second test transistor having a substantially different second stress level. A testing circuit can then be used to characterize the mechanical stress level by comparing performance of the first test transistor and the at least one second test transistor. The type of test structure depends on the integration scheme used. In one embodiment, at least one second test transistor is provided with a substantially neutral stress level and/or an opposite stress level from the first stress level. The substantially neutral stress level may be provided by either rotating the transistor, removing the stressed layer causing the stress level or de-stressing the stressed layer causing the stress layer.

Abstract: A projection optical system having a magnification side and a reduction side for forming a magnified image on a magnification side image surface conjugate with a reduction side conjugate image surface includes, arranged in order from the reduction side, a first imaging system including a plurality of lens elements and lens components and a second imaging system including a mirror having a concave, aspheric reflecting surface. An intermediate image is formed between the first imaging system and the second imaging system. The projection optical system satisfies specified conditions related to the travel of principal rays through the projection optical system and related to the Abbe number of a lens element having positive refractive power of the first imaging system. A projection display device includes the projection optical system and may include a light valve for modulating a light beam for projection on a screen.

Abstract: A folded, magnifying, front projection arrangement for video displays includes a video image source, such as a flat panel display unit out of the user's field of view, projects its image onto a concave mirror also out of the user's field of view. The video image source is maintained off-axis with respect to the optic axis of the concave mirror and at a distance from the concave mirror between one and two times the distance from the concave mirror to its principal focal surface, which would be the principal focal plane if the concave mirror were a spherical or a parabolic mirror. The concave mirror, in turn, reflects and focuses the light from the video image source onto a projection screen, within the user's field of view, resulting in a magnified image. The distortion of the projected image that would otherwise result from off-axis projection is compensated for by maintaining the plane of the video image source at a non-perpendicular angle to the optic axis of the mirror.