Adjustable transparency spectacles
First Claim
Patent Images
1. Eyewear having adjustable transparency comprising:
- at least one lens comprising means for varying the transparency thereof in response to a variation of voltage applied thereto,means for supplying said variable voltage connected to said transparency varying means,means for varying said variable voltage from said voltage supplying means applied to said transparency varying means,said means for varying the transparency of said lens comprising a liquid crystal cell including a pair of spaced transparent supports each having a transparent electrode to which said variable voltage from said voltage supplying means is applied to produce an electric field having a variable strength, a cholesteric-nematic phase change dichroic liquid crystal between said supports which transmits light in the absence of said electric field and which absorbs light in relation to the strength of said electric field, said liquid crystal having a double refraction lower than 0.12 and a negative dielectric anisotropy, at least one of said cell supports including means for imposing on the molecules of said liquid crystal a substantially vertical alignment, said liquid crystal having a spontaneous pitch value which is equal to 0.9-4 times the thickness of said cell.
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Abstract
Eyewear has variable transparency provided by a lens made of a non-diffusing dichroic liquid crystal cell with nematic-cholesteric phase change. A voltage source supplies an adjustable voltage to the liquid crystal cell; adjustment of the voltage to change the transparency of the lens is effected by a photocell which senses ambient light, or by manual control, or both.
197 Citations
17 Claims
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1. Eyewear having adjustable transparency comprising:
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at least one lens comprising means for varying the transparency thereof in response to a variation of voltage applied thereto, means for supplying said variable voltage connected to said transparency varying means, means for varying said variable voltage from said voltage supplying means applied to said transparency varying means, said means for varying the transparency of said lens comprising a liquid crystal cell including a pair of spaced transparent supports each having a transparent electrode to which said variable voltage from said voltage supplying means is applied to produce an electric field having a variable strength, a cholesteric-nematic phase change dichroic liquid crystal between said supports which transmits light in the absence of said electric field and which absorbs light in relation to the strength of said electric field, said liquid crystal having a double refraction lower than 0.12 and a negative dielectric anisotropy, at least one of said cell supports including means for imposing on the molecules of said liquid crystal a substantially vertical alignment, said liquid crystal having a spontaneous pitch value which is equal to 0.9-4 times the thickness of said cell. - View Dependent Claims (2, 3, 4, 5, 6, 11, 12, 13, 14, 15, 16, 17)
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7. Eyewear apparatus having adjustable transparency comprising:
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at least one lens comprising means for varying the transparency thereof in response to a variation of voltage applied thereto, means for supplying said variable voltage connected to said transparency varying means, means for varying said variable voltage from said voltage supplying means applied to said transparency varying means, said means for varying the transparency of said lens comprising a liquid crystal cell including a pair of spaced transparent supports each having a transparent electrode to which voltage from said voltage supplying means is applied to produce an electric field having a variable strength, a cholesteric-nematic phase change dichroic liquid crystal between said supports which absorbs light in the absence of the electric field and which transmits light in relation to the strength of said electric filed, said liquid crystal having a double refraction lower than 0.12 and a positive dielectric anisotropy, at least one of said cell supports including means for imposing on molecules of said liquid crystal an alignment substantially parallel thereto, said liquid crystal having a spontaneous pitch value which is more than one-half the thickness of said cell, and an effective torsion, at rest, which is substantially equal to 1/4-2 round angles. - View Dependent Claims (8, 9, 10)
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Specification