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

• US 5,654,786 A
• Filed: 01/11/1996
• Issued: 08/05/1997
• Est. Priority Date: 01/11/1996
• Status: Expired due to Term

• Current Assignee: Robert G. Burlingame
• Original Assignee: Robert C. Burlingame
• Inventors: Bylander, E. Gerald
• Primary Examiner(s): DANG, HUNG XUAN
• Application Number:
  US08/584,567
• Time in Patent Office: 572 Days
• Field of Search: 351/49, 351/158, 351/41, 351/44, 351/45, 351/46, 359/62, 359/63
• US Class Current: 351/49
• CPC Class Codes: A61F 9/023 with variable transmission, e.g. photochromic for welding A61F9/067
• CPC Class Codes: G02C 7/101 having an electro-optical light valve electro-optical elements per se G02F
• CPC Class Codes: G02C 7/12 Polarisers
• CPC Class Codes: G02F 1/0551 Constructional details

Abstract

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.

Claims

1. An optical device to be worn by a user comprising:

a) a lens structure having an optical transmissivity which is electrically controllable, the lens structure including a pair of lenses having a transmission layer therebetween, the transmission layer being responsive to a variable voltage applied thereto for varying an amount of light transmitted through the lens structure;

b) a frame coupled to the lens structure, wherein the frame places the lens structure in optical relationship with the user'"'"'s eyes;

c) a sensor mounted behind the lens structure to measure the amount of transmitted light passing through the lens structure; and

d) a control circuit electrically coupled to the lens structure and the sensor, and including a power source, the control circuit sensing and responding to the amount of light transmitted through the lens structure as measured by the sensor and electronically adjusting the optical transmissivity of the lens structure by varying the variable voltage applied to the transmission layer such that the amount of light transmitted through the lens remains within a predetermined range.

2. The optical device of claim 1 further comprising a second lens structure, the frame being configured to place the lens structure and the second lens structure in relationship to the user'"'"'s respective eyes.

3. The optical device of claim 1 wherein the transmission layer is a ferro-electric material and the pair of lenses are each polarizing lenses.

4. The optical device of claim 1 wherein the ferro-electric material is composed of a lead-lanthanum zirconate/titanate (PLZT).

5. The optical device of claim 1 wherein the transmission layer is a dichroic dye sealed between the pair of lenses.

6. An optical device for controlling an amount of light received at a wearer'"'"'s eye, the optical device comprising:

a) a frame;

b) a lens structure mounted in the frame, the lens structure including;

i) a first lens;

ii) a second lens;

iii) a transmission layer disposed between the first lens and the second lens, the transmission layer having a electro-optic property in response to and in proportion to an electric field placed across the transmission layer such that the transmission layer determines the amount of light that passes through the lens structure; and

iv) electrical terminals electrically connected across the transmission layer to produce an electric field across the transmission layer;

c) a sensor mounted behind the second lens to develop a signal proportional to the light passing through the lens structure;

d) a control circuit electrically connected to the sensor, the control circuit comparing the signal to a maximum transmission level and a minimum transmission level to ensure that the light passing through the lens structure is within a desired range; and

e) a power supply electrically connected to the electrical terminals and controlled by the control circuit, the power supply used to add and remove charge from the lens structure in response to the control circuit.

7. The optical device of claim 6 wherein the first lens and the second lens are polarizing lenses, the first lens used to polarized incident light into a transmission plane, and wherein the transmission layer is a ferro-electric material which continuously rotates the transmission plane in an amount proportional to the electric field such that a percentage of the transmission plane is absorbed by the second lens, the percentage corresponding to the amount of rotation.

8. The optical device of claim 7 wherein the power supply is a high voltage power supply capable of placing a voltage across the electrical terminals of at least 500 volts.

9. The optical device of claim 7 wherein the ferro-electric material is composed of a lead-lanthanum zirconate/titanate (PLZT).

10. The optical device of claim 6 wherein the transmission layer is a dichroic dye sealed between the first lens and the second lens, the dichroic dye increasing transmissivity in response to the electric field.

11. The optical device of claim 6 wherein the control circuit and the power supply are mounted in the frame.

12. An optical device for controlling an amount of light received at a wearer'"'"'s eye, the optical device comprising:

a) a frame;

b) a lens structure mounted in the frame, the lens structure including;

i) a first polarizer having a first plane of polarization to receive light incident on the optical device and to transmit polarized light, the polarized light being polarized in the first plane of polarization;

ii) a transmission layer adjacent the first polarizer to receive the polarized light, the transmission layer having an electro-optic property such that the transmission layer rotates the polarized light in response to and in an amount proportional to an electrical field placed across the transmission layer;

iii) a second polarizer adjacent the transmission layer opposite the first polarizer and having a second plane of polarization, the second polarizer to receive the polarized light rotated by the transmission layer and to transmit a percentage of the polarized light, the percentage corresponding to the amount of rotation and the second plane of polarization; and

iv) electrical terminals connected to the transmission layer, the electrical terminals capable of holding a charge, the charge inducing the electric field across the transmission layer;

c) a sensor mounted on the second lens opposite the transmission layer, the sensor generating a signal proportional to the percentage of polarized light transmitted by the second polarizer;

d) a high voltage power supply and electrically connected to the electrical terminals, the high voltage power supply used to control the charge on the electrical terminals by placing a voltage across the electrical terminals, wherein the voltage is continuously variable up to a maximum safe voltage; and

e) a control circuit and electrically connected to the sensor and the high voltage power supply, the control circuit receiving the signal from the sensor and causing the high voltage power supply to add or remove charge as necessary when the signal from the sensor is outside a desired operating range.

13. The optical device of claim 12 wherein the transmission layer material is composed of a lead-lanthanum zirconate/titanate (PLZT).

14. The optical device of claim 12 wherein the first plane of polarization and the second plane of polarization are in an identical orientation such that the lens structure is transparent when the electric field across the transmission layer is zero.

15. The optical device of claim 12 wherein the first plane of polarization is perpendicular to the second plane of polarization such that the lens structure is opaque when the electric field across the transmission layer is zero.

16. The optical device of claim 12 wherein the frame includes a seal extending from the frame to a forehead of the wearer and a first and second earpieces, the seal and the first and second earpieces providing a barrier to prevent ambient light from reaching the sensor.

17. The optical device of claim 12 wherein the sensor is a photoamperic sensor configured to generate a current when exposed to a light source.

18. The optical device of claim 17 wherein the photoamperic sensor is a gallium arsenide phosphide light emitting diode which generates the current in response to light in essentially a visible spectrum.

19. The optical device of claim 12 wherein the high voltage power supply and the control circuit are mounted in the frame.

20. An optical device for maintaining a preset transmission level of light at a wearer'"'"'s eye, the eyewear apparatus comprising:

a) a frame including a left earpiece and a right earpiece and a seal, the left earpiece, the right earpiece and the seal preventing light from reaching the wearer'"'"'s eye other than through the eyewear apparatus;

b) a lens structure mounted in the frame and including a first and second lens, each of the first and second lenses formed by

i) a first polarizer mounted in frame and having a first plane of polarization, wherein the first polarizer receives ambient light and transmits polarized light;

ii) a lead-lanthanum zirconate/titanate (PLZT) layer mounted in the frame adjacent the first polarizer, the (PLZT) layer including a plurality of filaments such that an electric field is developed across the (PLZT) layer when a voltage is applied to the plurality of filaments, wherein the (PLZT) layer receives the polarized light, rotates the polarized light in an amount proportional to the electric field, and transmits rotated polarized light;

iii) a second polarizer mounted in the frame adjacent to the (PLZT) layer opposite the first polarizer, the second polarizer having a second plane of polarization, wherein the second polarizer receives the rotated polarized light from the (PLZT) layer and transmits the preset light level to the wearer'"'"'s eye; and

iv) electrical terminals electrically connected to the plurality of filaments;

c) a sensor mounted on the second polarizer of the first lens, wherein the sensor develops a signal proportional to the preset light level transmitted by the second polarizer of the first lens;

d) a high voltage power supply mounted in the frame and electrically connected to the electrical terminals, wherein the high voltage power supply supplies a continuously variable voltage to the electrical terminals and a maximum safe voltage of at least 500 volts;

e) a control circuit mounted in the frame, the control circuit being electrically connected to the sensor and the high voltage power supply, wherein the control circuit causes the high voltage power supply to alter the continuously variable voltage across the electrical terminals in response to the signal from the sensor corresponding to the preset light level having strayed outside a preset transmission range.

21. The optical device of claim 20 wherein the first plane of polarization and the second plane of polarization are in an identical orientation such that the lens structure is transparent when the electric field across the transmission layer is zero.

22. The optical device of claim 20 wherein the first plane of polarization is perpendicular to the second plane of polarization such that the lens structure is opaque when the electric field across the transmission layer is zero.

23. The optical device of claim 20 wherein the sensor is a light emitting diode configured to generate a current when exposed to a light source.

24. The optical device of claim 20 wherein the light emitting diode is a Gallium Arsenide Phosphide diode which generates the current in response to light in essentially a visible spectrum.