Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1998-06-24
2001-05-29
Wu, Xiao (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S211000, C349S033000
Reexamination Certificate
active
06239778
ABSTRACT:
TECHNICAL FIELD
The present invention generally relates to a dichroic dye guest-host cell with electronically attenuated light transmission. More specifically, the present invention relates to a cell having light absorbing dichroic dyes dissolved or suspended in a host solution.
BACKGROUND ART
On the market today there are a lot of devices, particularly sunglasses, that have photosensitive light transmissivity. Some of these devices use chemical compounds that enter an excited state upon exposure to light—when in this excited state, they absorb more light. The primary drawback of this technology is that these compounds are slow to respond to a change in light conditions. For example, a sunglass wearer driving into a tunnel on a sunny day will have glasses that are too dark (too light absorbent) upon entry and too clear (too light transmissive) upon exiting the tunnel due to a slow change in light absorptivity. As a result, the wearer is put in an uncomfortable and potentially dangerous situation.
Sunglasses that use liquid crystals are also known. Typically, a liquid crystal cell is placed between two polarizing layers. The liquid crystal modifies the polarization state of the transversing light. The polarizers, not dyes, are used to absorb light. The only use of dyes in the prior art is non-functional, generally for tint, as exemplified by U.S. Pat. No. 4,968,127. At least two major drawbacks to this construction is, first, that transmittance of light depends on the viewing angle, and second, it is hard to implement on a plastic substrate. As is well known, polarizers significantly reduce the viewing angle of the cell. In addition, the transmittance of light is typically too small for use in low lighting conditions. In U.S. Pat. No. 5,015,086, for example, the highest transmission reported was 35%.
Therefore, there is a need for a device where the transmittance of light is constant at all viewing angles, where attenuation of transmitted light is continuously and rapidly controllable, and where the device can be implemented on plastic substrates.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a device capable of continuous attenuation of light transmission without the need for polarizing the light.
It is another object of the present invention to provide a device capable of rapid attenuation of light transmission.
It is yet another object of the present invention to provide a device with controllable sensitivity to polarized or unpolarized light.
It is still another object of the present invention to provide a device with controllable transmittance and controllable response time.
It is a further object of the present invention to provide a fail-safe device, i.e., one with high light transmittance when no electrical power is supplied.
It is another object of the present invention to provide a guest-host system that can be used with glass or plastic substrates.
It is still a further object of the present invention to provide a device that can be designed to accommodate any desired color or tint.
At least one or more of the foregoing objects, together with the advantages thereof over known methods and articles, which shall become apparent from the specification which follows, are accomplished by the invention as hereinafter described and claimed.
In general, the present invention provides a variable light attenuating dichroic dye guest-host device comprising a pair of opposed substrates, each substrate having a conducting layer facing the other substrate, a host material such as a liquid crystal having a guest dichroic dye dispersed therethrough, the guest-host material received between the substrates, and a power circuit having a variable voltage supply connected to the conducting layers, wherein adjustment of the variable voltage supply alters the light transmission properties of the cell by adjusting the orientation of the dichroic dye.
The present invention also provides a polarizer-free variable light attenuating device, comprising a pair of opposed substrates, each substrate having a conducting layer facing the other substrate, a host material received between said substrates, a power circuit having a variable voltage supply connected to the conducting layers, wherein adjustment of the variable voltage supply alters the orientation of the host material without absorbing or polarizing any light transmitted through the pair of opposed substrates, and a dichroic dye guest dispersed through the host material, wherein the molecular axis of the dichroic dye orients with respect to the molecular axis of the host material such that a change in the orientation of the host material causes the dichroic dye guest to change absorption of transmitted light through the pair of opposed substrates.
REFERENCES:
patent: D. 321701 (1991-11-01), Nomura et al.
patent: 4150878 (1979-04-01), Barzilai et al.
patent: 4279474 (1981-07-01), Belgorod
patent: 4281903 (1981-08-01), Gharadjedaghi
patent: 4511225 (1985-04-01), Lipson
patent: 4756605 (1988-07-01), Okada et al.
patent: 4795248 (1989-01-01), Okada et al.
patent: 4968127 (1990-11-01), Russell et al.
patent: 5015086 (1991-05-01), Okaue et al.
patent: 5067795 (1991-11-01), Senatore
patent: 5114218 (1992-05-01), Black et al.
patent: 5172256 (1992-12-01), Sethofer et al.
patent: 5608567 (1997-03-01), Grupp
patent: 5710609 (1998-01-01), Shimada
patent: 5712721 (1998-01-01), Large
patent: 61026021 (1986-02-01), None
patent: 01150114 (1989-06-01), None
F. Gharadjedaghi, A Positive Contrast Guest-Host Display Using a Liquid Crystal of Negative Dielectric Anisotropy, Physics Group 1981 (pp. 127-135).
Nasuno T et al.,Electro-Optical Properties of Guest-Host LC Cell Using Vertically Aligned Nematic LC And Its Application To Reflective Type LCD, Institute of Electrical Engineers, Research Reports of Kogakuin University, Japan, No. 83 (Oct. 1997), Abstract of pp. 57-62.
Kosa Tamas
Palffy-Muhoray Peter
Taheri Bahman
AlphaMicron, Inc.
Renner Kenner Grieve Bobak Taylor & Weber
Wu Xiao
LandOfFree
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