Nonemissive displays and piezoelectric power supplies therefor
AssigneeMassachusetts Institute of Technology
InventorsJoseph M. Jacobson, Barrett Comiskey
Life of this patent
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Abstract
An electrophoretic display has a substantially two-dimensional arrangement of microcapsules each having therein an electrophoretic composition of a dielectric fluid and a suspension of particles that visually contrast with the dielectric liquid and also exhibit surface charges; a pair of electrodes, at least one of which is visually transparent, disposed on and covering opposite sides of the microcapsule arrangement; and means for creating a potential difference between the two electrodes, the potential difference causing the particles to migrate toward one of the electrodes. The display may be powered by one or more piezoelectric elements, which are also suitable for powering other types of nonemissive displays.
Claims21
An electrophoretic display comprising:
- a. an arrangement of discrete microscopic containers, each container being no longer than 500 .mu.m along any dimension thereof;
- b. first and second electrodes disposed on and covering opposite sides of the arrangement, at least one of the electrodes being substantially visually transparent;
- c. means for creating a potential difference between the two electrodes;
- and
- d. within each container, a dielectric fluid and a suspension therein of particles exhibiting surface charges, the fluid and the particles contrasting visually, the potential difference causing the particles to migrate toward one of the electrodes.
A nonemissive display system comprising:
- a. a pair of oppositely disposed electrodes and, located therebetween, at least one display element, the display element being visually responsive to a potential difference between the electrodes;
- b. a display piezoelectric element connected to the electrodes, deformation of the piezoelectric element producing the potential difference;
- c. a driver piezoelectric element acoustically coupled to the display piezoelectric element;
- d. means for applying an AC voltage to the driver element at a driver frequency so as to cause the display piezoelectric element to produce an AC voltage;
- and
- e. means for rectifying the AC voltage from the display piezoelectric element, the rectified voltage providing the potential difference.
A nonemissive display system comprising:
- a. a pair of oppositely disposed electrodes and, located therebetween, at least one display element, the display element being visually responsive to a potential difference between the electrodes;
- b. a display piezoelectric element connected to the electrodes, deformation of the piezoelectric element producing the potential difference;
- c. a driver piezoelectric element acoustically coupled to the display piezoelectric element;
- d. means for applying an AC voltage to the driver element at a driver frequency so as to cause the display piezoelectric element to produce an AC voltage, the AC voltage providing the potential difference;
- e. at least one filter intervening between the display piezoelectric element and the electrodes, the at least one filter configured to (i) pass AC within a predetermined frequency band so that the display is unaffected by driver frequencies outside the predetermined band, or (ii) drop AC within a predetermined frequency band so that the display is affected only by driver frequencies outside the predetermined band;
- and
- f. means, connected to the display piezoelectric element, for rectifying the AC voltage from the filter and thereby providing the potential difference.
A nonemissive display system comprising:
- a. a pair of oppositely disposed electrodes and, located therebetween, at least one display element, the display element being visually responsive to a potential difference between the electrodes;
- and
- b. a display piezoelectric element connected to the electrodes, deformation of the piezoelectric element producing the potential difference;
- wherein the display element comprises:
- c. a substantially two-dimensional arrangement of discrete microscopic containers, each container being no longer than 500 .mu.m along any dimension thereof;
- and
- d. within each container, a dielectric fluid and a suspension therein of particles exhibiting surface charges, the fluid and the particles contrasting visually, the potential difference causing the particles to migrate toward one of the electrodes.
Dependencies are inferred from the claim text.