Optical lens structure and control system for maintaining a selected constant level of transmitted light at a wearer's eyes

摘要

A lens structure and electronic control system is provided for use in eyeglasses. The lens structure is formed by a pair of lenses with a transmission layer formed by an electro-optic material is disposed therebetween. The transmission layer is used to control the amount of light that is transmitted through the lens structure by placement of a variable voltage placed across it. The transmission layer can be formed by either a dichroic dye or by a ferro-electric material such as PLZT. The electronic control system uses a photoamperic sensor placed behind the lens structure to develop a current proportional to the transmitted light. The current is converted into a voltage which is compared to a desired transmission range. If the sensed transmission level is outside the desired range the control circuit causes a power supply to add or decrease the charge across the lens as necessary to bring the transmitted light level back into the desired range. The use of a ferro-electric material also requires the use of a high voltage power supply to provide the necessary voltages to operate the lens structure.