Method to prevent emulsion in a liquid lens

Abstract

Embodiments generally relate to methods for preventing the formation of an emulsion in a liquid lens. In one embodiment, the method comprises fabricating a top substrate, a bottom s substrate, and a central substrate including a cavity configured to be filled by first and second liquids. The liquid lens comprising the top substrate, the bottom substrate and the central substrate is assembled, with at least one of the top substrate and the bottom substrate in the assembled liquid lens being characterized by a stabilizing feature determining that in response to an impact load on the assembled liquid lens that would cause localized pressure drops of 10 maximum magnitude X in the absence of the stabilizing feature, the maximum magnitude of localized pressure drops within the liquid lens is smaller than X.

What is claimed is: 
     
         1 . A liquid lens comprising:
 a first substrate comprising a central portion, at least a portion of the central portion of the first substrate having a reduced thickness compared to a remaining portion of the first substrate;   a second substrate comprising a cavity formed therein and bonded to the first substrate such that the central portion of the first substrate at least partially overlies the cavity of the second substrate; and   first and second fluids disposed within the cavity and in contact with each other to form a meniscus between the first and second fluids;   wherein the central portion of the first substrate deflects in response to a change in an internal pressure within the cavity.   
     
     
         2 . The liquid lens of  claim 1 , wherein the first and second fluids are hermetically sealed within the cavity. 
     
     
         3 . The liquid lens of  claim 1 , wherein the central portion of the first substrate is integral with the remaining portion of the first substrate. 
     
     
         4 . The liquid lens of  claim 1 , wherein the central portion of the first substrate is integral with and formed from the same material as the remaining portion of the first substrate. 
     
     
         5 . The liquid lens of  claim 1 , wherein the first fluid has a different index of refraction than the second fluid such that the meniscus functions as a lens. 
     
     
         6 . The liquid lens of  claim 1 , comprising a third substrate bonded to the second substrate such that the second substrate is disposed between the first substrate and the third substrate. 
     
     
         7 . The liquid lens of  claim 1 , wherein each of the first substrate and the second substrate is formed from a glass material. 
     
     
         8 . The liquid lens of  claim 7 , wherein the central portion of the first substrate is formed from the same material as the remaining portion of the first substrate. 
     
     
         9 . A liquid lens comprising:
 a first substrate comprising a central portion with reduced thickness compared to a remaining portion of the first substrate;   a second substrate comprising a cavity formed therein and bonded to the first substrate such that the central portion of the first substrate at least partially overlies the cavity of the second substrate; and   first and second fluids disposed within the cavity and in contact with each other to form a meniscus between the first and second fluids;   wherein the central portion of the first substrate is configured to bulge outward in response to an increase in a temperature of the first and second fluids disposed within the cavity.   
     
     
         10 . The liquid lens of  claim 9 , wherein the first substrate comprises a micro-stiffening element. 
     
     
         11 . The liquid lens of  claim 10 , wherein the central portion of the first substrate is substantially circular, and the micro-stiffening element comprises a rib extending from the remaining portion of the first substrate into the central portion. 
     
     
         12 . The liquid lens of  claim 9 , wherein the first and second fluids disposed within the cavity are under positive pressure resulting from an inbuilt stress in the first substrate. 
     
     
         13 . The liquid lens of  claim 9 , wherein the central portion of the first substrate and the remaining portion of the first substrate are formed from the same material. 
     
     
         14 . The liquid lens of  claim 9 , wherein the central portion of the first substrate and the remaining portion of the first substrate are integrally formed from a glass material. 
     
     
         15 . The liquid lens of  claim 9 , wherein a thickness of the central portion of the first substrate is at least 10% less than a thickness of the remaining portion of the first substrate. 
     
     
         16 . The liquid lens of  claim 9 , wherein the second substrate is bonded to the first substrate at a hermetic bond. 
     
     
         17 . The liquid lens of  claim 9 , wherein a stiffness of the central portion of the first substrate is sufficiently low to enable deflection of the central portion in response to the increase in the temperature of the first and second fluids disposed within the cavity and sufficiently high to limit a local pressure drop within the cavity in response to an impact to a level at which there is no substantial emulsion of the first and second fluids. 
     
     
         18 . A liquid lens comprising:
 a housing comprising a cavity and a membrane at least partially overlying the cavity;   first and second fluids disposed within the cavity and in contact with each other to form a meniscus between the first and second fluids;   wherein the membrane comprises a glass material and deflects outward in response to an increase in a temperature of the first and second fluids disposed within the cavity.   
     
     
         19 . The liquid lens of  claim 18 , wherein the housing comprises:
 a first substrate comprising the membrane; and   a second substrate comprising the cavity formed therein and bonded to the first substrate such that the membrane at least partially overlies the cavity.   
     
     
         20 . The liquid lens of  claim 19 , wherein the membrane of the first substrate comprises a central portion of the first substrate with reduced thickness compared to a remaining portion of the first substrate.