Variable transmittance optical devices
A self-powered variable transmittance optical device, such as a smart window or other device, and associated method are provided. The device comprises one or more transparent substrates, with a switching material disposed thereon or therebetween. The switching material may be a hybrid photochromic/electrochromic material capable of transitioning from a first transmittance state to a second transmittance state with application of electricity, and from second state to first state due to another stimulus, such as UV radiation. Electrodes are coupled to the switching material for applying electricity. An electrical system provides for controllable application of the electricity, and may store energy. Energy is provided by an energy-harvesting power source such as a solar cell or other photovoltaic source, or array thereof, or another device for harvesting vibrational or thermal energy. Energy harvesting, energy storage capacity and/or switching material may be configured to provide at least a predetermined level of device operability.
1. A self-powered variable transmittance optical device film comprising:
(a) a first and second substantially transparent substrate;
(b) a switching material flexibly disposed on at least one of the first and second substantially transparent substrates, the switching material capable of transitioning between a light state and a dark state based at least in part on application of an electric voltage;
(c) a first and second electrode both disposed on the first substantially transparent substrate, both disposed on the second substantially transparent substrate, or each disposed on one of the substantially transparent substrates;
(d) an energy-harvesting power source flexibly disposed on the device film; and
(e) an electrical system configured to receive power from the energy-harvesting power source and to provide power to the first electrode and the second electrode for application of the electric voltage, the electrical system disposed on the device film.
2. The optical device film of claim 1 , wherein the optical device film comprises a window in a vehicle.
3. The optical device film of claim 1 , wherein the optical device film comprises a sunroof.
4. A window comprising:
(a) a variable transmittance optical (VTO) filter comprising:
(i) a first substantially transparent substrate;
(ii) a second substantially transparent substrate;
(iii) a first and second electrode both disposed on the first substantially transparent substrate, both disposed on the second substantially transparent substrate, or each disposed on one of the substantially transparent substrates;
(iv) a switching material disposed between the first and second transparent substrates and operatively coupled to the first and second electrodes, the switching material transitionable from a first light transmittance state to a second light transmittance state with application of a first stimulus, and transitionable from the second light transmittance state to the first light transmittance state with application of a second stimulus, wherein at least one of the first stimulus and the second stimulus comprises a voltage applied to the switching material through the first and second electrodes;
(b) an energy harvesting power source; and
(c) an electrical system configured to receive power from the power source and to provide the voltage to the first electrode and the second electrode, wherein the electrical system comprises an energy storage component configured to receive and store power from the energy-harvesting power source, and to provide power for application of the voltage to the switching material,
wherein transitioning of the switching material from the first transmittance state to the second transmittance state under predetermined conditions requires an operating power exceeding a power delivery capacity of the energy-harvesting power source, and wherein the energy storage component is configured to facilitate providing the operating power under the predetermined conditions.
5. The window of claim 4 , wherein the switching material comprises a compound that exhibits photochromic and electrochromic characteristics.
6. The window according to claim 4 , wherein the energy-harvesting power source is selected from the group consisting of a piezoelectric power source, a photovoltaic power source, a vibrational energy-harvesting power source and a thermal energy-harvesting power source.
7. The window according to claim 4 , wherein the energy-harvesting power source is a photovoltaic power source.
8. The window according to claim 7 , wherein the photovoltaic power source has an area from about 1% to about 25% of the area of the variable transmittance optical filter.
9. The window according to claim 8 , wherein the energy-harvesting power source is disposed on a surface of the window.
10. The window according to claim 8 , wherein the energy-harvesting power source is disposed away from a surface of the window.