Switchable lens
First Claim
Patent Images
1. A lens assembly comprising:
- a lens including a layer of cholesteric liquid crystal having a property which may be switched by application of an electric or magnetic field, said property being at least one of focal length, absorption, color and effective aperture, without employing a polarizer;
switching means coupled to the lens to provide a drive impulse to switch the property of the lens; and
a power source coupled to the switching means to provide power for the switching means.
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Accused Products
Abstract
A lens assembly (1) comprises a lens (2;10,11;20) the focal length of which may be changed by application of an electric or magnetic field. A switching means (4,15) provides a drive impulse to change the focal length of the lens (2;10,11;20). An integral power source (4,15) provides power for the switching means. A lens which can be switched between near and distance vision by the user is thereby provided.
454 Citations
24 Claims
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1. A lens assembly comprising:
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a lens including a layer of cholesteric liquid crystal having a property which may be switched by application of an electric or magnetic field, said property being at least one of focal length, absorption, color and effective aperture, without employing a polarizer; switching means coupled to the lens to provide a drive impulse to switch the property of the lens; and a power source coupled to the switching means to provide power for the switching means. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A lens assembly comprising:
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a lens having a property which may be switched by application of an electric or magnetic field, said property being at least one of focal length, absorption, color and effective aperture; switching means coupled to the lens to provide a drive impulse to switch the property of the lens; a power source coupled to the switching means to provide power for the switching means; and wherein the switching means includes means for detecting a drop in a level of ambient light and changing the property of the lens when the level of detected light level drops for longer than a predetermined period of time. - View Dependent Claims (8, 9, 10, 11, 12, 13, 15, 16)
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14. An assembly according to claim 14 wherein the liquid crystal contains a dichroic dye.
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17. A lens assembly comprising:
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a lens having a property which may be switched by application of an electric or magnetic field, said property being at least one of focal length, absorption, color and effective aperture; switching means coupled to the lens to provide a drive impulse to switch the property of the lens; and a power source coupled to the switching means to provide power for the switching means wherein the power source is a battery which is operable using tear fluid.
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18. A lens assembly comprising:
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a lens including a layer of liquid crystal which may be switched between two different focal lengths, independent of polarization of the incident light, by application of an electric or magnetic field; switching means coupled to the lens to provide a drive impulse to switch the focal length of the lens; and a power source coupled to the switching means to provide power for the switching means. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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Specification