Design and fabrication of a prototype projection data monitor with high information content

Melcher, R. L.; Alt, P. M.; Dove, D. B.; Cipolla, T.M.; Colgan, E. G.; Doany, F. E.; Enami, K.; Ho, Kuan-Hsien; Lovas, I.; Narayan, C.; Olyha, R. S.; Powell, C. G.; Rosenbluth, Alan E.; Sanford, J. L.; Schlig, E.S.; Singh, Rama N.; Tomooka, T.; Uda, M.; Yang, K. H.

doi:10.1147/rd.423.0321

Cited by 22 publications

(10 citation statements)

References 6 publications

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“…It follows that in the hypothetical case of a reflective light valve whose Jones matrix takes the form of a retarder (eq. [5]), the phase ALV of the depolarization is half that of the retardation. It is the phase of the light valve depolarization rather than its birefringence which interacts with the optics depolarization (per eq.[38]).…”

Section: Correction Of Depolarization In Projector (Optics and Light mentioning

confidence: 98%

“…However, eqs. [2], [4] and [5] imply that even an LV with zero black-state reflectivity (in isolation from the optics) can impose a rotational depolarization on the principal ray when it reaches the mirror backplane. It can be shown that with such a light valve the optics is corrected in double-pass when the remaining ray-dependent backplane depolarization is purely elliptical [8].…”

Section: Correction Of Depolarization In Projector (Optics and Light mentioning

confidence: 99%

“…Reflective LCOS light valves provide a number of advantages in projection displays [1][2][3][4][5][6]. Readily available IC process technology provides very fine pixel dimensions (with associated shrinkage of light valve and optics), the liquid crystal (LC) layer can generally be made thinner and faster because of double-pass traversal, the backside of the light valve (LV) is available for cooling and control circuitry (increasing the front-surface aperture ratio), and the optical system can be folded back upon itself for greater compactness.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

<title>Correction of contrast in projection systems by means of phase-controlled prism coatings and band-shifted twist compensators</title>

Rosenbluth

Yang

et al. 2000

SPIE Proceedings

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Projectors that use LCOS lightvalves face special contrast requirements. Most configurations for reflective light valves employ tilted beam-dividing coatings that see both bright and dark polarization states. The optics must then be designed to eliminate polarization mixing at these coatings, which ordinarily arises when the S and P planes for different rays are non-parallel. We show how phase-controlled coatings can exploit the double-pass symmetry of the Plumbicon tn-prism geometry to correct this effect, reducing cross-polarized reflectivity to ---1E-3 when the light valve is mirror-like in black-state. Though contrast in different rays varies as a function of both ray skew component and coating angle of incidence, we show that for NA0.2 the computation involved in calculating beam contrast is essentially equivalent to tracing a single ray. Light valves that use a normally-black TN mode exhibit a non-mirror-like phase dispersion in their black-state, complicating contrast control in the optics. Scatter depolarization at the edges of pixel electrodes is enhanced in these light valves, because the inherent twist causes the backplane polarization to be rotated out of alignment with pixel edges. We show that all of these contrast degradation mechanisms can be addressed by incorporating into the light valve a compensating layer having opposite birefringence to the black-state TN active layer. Moreover, when the compensating layer and driven layer are blue-shifted to a shorter LC thickness than would ordinarily be appropriate for the wavelength band of interest, a highly achromatic response is obtained at all gray levels.

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Section: Correction Of Depolarization In Projector (Optics and Light mentioning

confidence: 98%

Section: Correction Of Depolarization In Projector (Optics and Light mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

<title>Correction of contrast in projection systems by means of phase-controlled prism coatings and band-shifted twist compensators</title>

Rosenbluth

Yang

et al. 2000

SPIE Proceedings

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“…Although the early prototypes of LCOS projection light valves used either polarizer-free liquid crystal modes, such as polymer-dispersed liquid crystal (PDLC) [4], [6] and nematic curvilinear aligned phase (NCAP) [9], or used twisted nematic derived modes [3], [10], the mode of choice for LCOS devices is the vertically aligned nematic mode (VAN). This preference is based on the superior characteristics of VAN in some areas, notably contrast and brightness combined with very reasonable performance in all other areas, such as driving voltage, response speed and acceptance angle.…”

Section: Liquid Crystal Technologymentioning

confidence: 99%

VAN LCOS Microdisplays: A Decade of Technological Evolution

Cuypers

Smet

Calster

2011

J. Display Technol.

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Abstract-Microdisplays of the liquid crystals on silicon (LCOS)type have gone through a rapid evolution during the last decade. We present an overview of how vertically aligned nematic (VAN) LCOS have evolved from an attractive, but notoriously difficult and even infamous technology, to the mainstream microdisplay technology that it is today. At the same time, we highlight a number of remaining issues and concerns, and present some ideas of how to remedy them. Index Terms-Liquid crystals on silicon (LCOS), microdisplay, vertically aligned nematic (VAN).

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“…Recently, Alt [1] and Melcher et al [2] reported a prototype rear projector having a resolution of 2048 by 2048 pixels using three Si-wafer-based liquid crystal (LC) SLMs which utilized a 45°-twisted nematic [or hybrid field-effect (HFE)] mode [3].…”

Section: Introductionmentioning

confidence: 99%

Nematic LC modes and LC phase gratings for reflective spatial light modulators

Yang

1998

IBM J. Res. & Dev.

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Single-domain nematic liquid crystal (LC) devices based on the polarization-rotation effect, the birefringent effect, or both have been investigated for reflective spatial light modulators (SLMs) which use a polarizing beam splitter to separate the input light beam from its orthogonal output beam. We have evaluated each LC mode in terms of its contrast ratio, optical efficiency, operating voltage, and tolerance to cell-gap nonuniformity. We studied the hybridaligned and the 0"-, 45°-, and 63.6°-twisted nematic LC modes, which can be operated either normally white (NW) or normally black (NB). We have also investigated the mixed twisted nematic (MTN) and self-compensated twisted nematic (SCTN) modes in NW and the tilted homeotropic mode in NB. Twodimensional simulations have also been carried out for both NW and NB modes implemented in active-matrix-driven reflective SLMs to elucidate the effect of fringe fields, which tend to generate disclination lines in high-field on-pixels adjacent to low-field off-pixels. Numerical examples are given to illustrate that, for the NB modes, the disclination lines occurring in the field-on bright state appear dark and reduce the optical efficiency. However, for the NW modes, the disclination lines occurring In the field-on dark states generate a light leakage which degrades the contrast ratio. To improve optical efficiency, we have also studied polarizationindependent LC phase gratings using patterned alignment with opposite twist angles for reflective SLMs. The basic equations for the diffracted and nondiffracted intensities have been derived. The device parameters, operating voltage, and optical efficiency are given for various cases with a twist angle equal to or less than 90°.

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Design and fabrication of a prototype projection data monitor with high information content

Cited by 22 publications

References 6 publications

<title>Correction of contrast in projection systems by means of phase-controlled prism coatings and band-shifted twist compensators</title>

<title>Correction of contrast in projection systems by means of phase-controlled prism coatings and band-shifted twist compensators</title>

VAN LCOS Microdisplays: A Decade of Technological Evolution

Nematic LC modes and LC phase gratings for reflective spatial light modulators

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