28-06-2010, 06:18 PM
fluid focus Lenses
This is a a unique variable-focus lens system that has no mechanical moving parts. This can come into application in areas such as digital cameras, camera phones, endoscopes, home security system, optical storage devices etc. It may consist of two immiscible fluids of different refractive indices: one a electrically conducting aqueous solution and the other an electrically non-conducting oil. They are housed in a short tube with end caps which are coated with a hydrophobic coating that makes this solution to form the shape of a hemispherical mass at the opposite end of the tube. Thuis it acts as a spherically curved lens.
When an an electric field across the hydrophobic coating, electrowetting happens ,ie, it becomes less hydrophobic.Due to this surface-tension the aqueous solution begins to wet the sidewalls of the tube. this causes the radius of curvature of the meniscus between the two fluids to alter and hance altering the focal length of the lens. The lens can be made completely flat (no lens effect) or even concave. be changing the magnitude of the electric field applied. Thus the lens acn be convex to flat to concave by just varying the elctric field strength.
This works on the principle of mimics the action of the human eye using a fluid lens that alters its focal length by changing its shape.This also overcomes the fixed-focus disadvantages of present lenses.
For more details, refer these links:
http://physorgnews308.html
http://photonicsArticle.aspx?AID=24918
http://freepatentsonlineEP1966635.html
http://imre.a-star.edu.sg/Upload/Fluid_Lens.pdf
This is a a unique variable-focus lens system that has no mechanical moving parts. This can come into application in areas such as digital cameras, camera phones, endoscopes, home security system, optical storage devices etc. It may consist of two immiscible fluids of different refractive indices: one a electrically conducting aqueous solution and the other an electrically non-conducting oil. They are housed in a short tube with end caps which are coated with a hydrophobic coating that makes this solution to form the shape of a hemispherical mass at the opposite end of the tube. Thuis it acts as a spherically curved lens.
When an an electric field across the hydrophobic coating, electrowetting happens ,ie, it becomes less hydrophobic.Due to this surface-tension the aqueous solution begins to wet the sidewalls of the tube. this causes the radius of curvature of the meniscus between the two fluids to alter and hance altering the focal length of the lens. The lens can be made completely flat (no lens effect) or even concave. be changing the magnitude of the electric field applied. Thus the lens acn be convex to flat to concave by just varying the elctric field strength.
This works on the principle of mimics the action of the human eye using a fluid lens that alters its focal length by changing its shape.This also overcomes the fixed-focus disadvantages of present lenses.
For more details, refer these links:
http://physorgnews308.html
http://photonicsArticle.aspx?AID=24918
http://freepatentsonlineEP1966635.html
http://imre.a-star.edu.sg/Upload/Fluid_Lens.pdf
