Heated ferroelectric liquid crystal spatial light modulator with improved contrast, improved grayscale resolution, and decreased pixel sticking when operated in a non-DC balanced mode
First Claim
1. A ferroelectric liquid crystal-based spatial light modulator with decreased pixel sticking, when operated in a non-DC-balanced mode with spiking, comprising:
- a transparent electrode;
a pixellated electrode;
ferroelectric liquid crystal material sandwiched between the transparent electrode and the pixellated electrode; and
a heater capable of preheating the ferroelectric liquid crystal material to raise the temperature of the ferroelectric liquid crystal material to a temperature of at least 40°
C. prior to the non-DC-balanced operation of the spatial light modulator, wherein the preheating of the ferroelectric liquid crystal material reduces pixel sticking due to the non-DC-balanced operation of the spatial light modulator.
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Accused Products
Abstract
A heated ferroelectric liquid crystal-based spatial light modulator (SLM) that minimizes pixel sticking when operated in a non-DC-balanced mode with spiking and method for using same. The SLM comprises a transparent electrode, a pixellated electrode, ferroelectric liquid crystal material, and a heater. The ferroelectric liquid crystal material is sandwiched between the transparent electrode and the pixellated electrode. The heater is capable of heating the ferroelectric material to at least 40° C. and preferably to between 50 and 60° C. The invention may also provide a temperature sensor for detecting the temperature of the SLM and a temperature control circuit that is electrically connected to both the temperature sensor and the heater. The temperature sensor may be a diode located proximate to the pixellated electrode or a photo-diode located remote from the spatial light modulator. The heater may be integrated into and encapsulated by a substrate supporting the pixellated electrode or it may be supported on a second major surface of the substrate. The method according to the invention includes providing a SLM, preheating the SLM, and operating the SLM in a non-DC-balanced mode with spiking while monitoring and maintaining the a temperature of the SLM above 50° C.
145 Citations
23 Claims
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1. A ferroelectric liquid crystal-based spatial light modulator with decreased pixel sticking, when operated in a non-DC-balanced mode with spiking, comprising:
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a transparent electrode; a pixellated electrode; ferroelectric liquid crystal material sandwiched between the transparent electrode and the pixellated electrode; and a heater capable of preheating the ferroelectric liquid crystal material to raise the temperature of the ferroelectric liquid crystal material to a temperature of at least 40°
C. prior to the non-DC-balanced operation of the spatial light modulator, wherein the preheating of the ferroelectric liquid crystal material reduces pixel sticking due to the non-DC-balanced operation of the spatial light modulator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of minimizing pixel sticking in a ferroelectric liquid crystal-based spatial light modulator operating in a non-DC-balanced mode, the method comprising:
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a) providing a ferroelectric liquid crystal-based spatial light modulator including a transparent electrode, a pixellated electrode, and ferroelectric liquid crystal material sandwiched between the transparent electrode and the pixellated electrode; b) operating the ferroelectric liquid crystal-based spatial light modulator in a non-DC-balanced mode; c) spiking the voltage applied to the transparent electrode periodically; and d) heating the ferroelectric liquid crystal material as required to maintain a temperature above 50°
C. while operating the spatial light modulator in a non-DC-balanced mode, wherein said heating reduces pixel sticking in the spatial light modulator due to the non-DC-balanced operation of the spatial light modulator. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. For a spatial light modulator that includes a transparent electrode, a pixellated electrode, and ferroelectric liquid crystal material sandwiched between the transparent electrode and the pixellated electrode, a method of minimizing pixel sticking in the spatial light modulator, the method comprising:
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a) operating the spatial light modulator in a non-DC-balanced mode; b) preheating the ferroelectric liquid crystal material to raise the temperature of the ferroelectric liquid crystal material to at least a first temperature before operating the spatial light modulator in the non-DC-balanced mode; and c) heating the ferroelectric liquid crystal material to at least a second temperature greater than the first temperature while operating the spatial light modulator in a non-DC-balanced mode, wherein said preheating and heating of the ferroelectric liquid crystal material reduce pixel sticking in the spatial light modulator due to the non-DC-balanced operation of the spatial light modulator. - View Dependent Claims (20, 21, 22, 23)
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Specification