Device for operating functional elements having electrically controllable optical properties

1. A device having at least one functional element having electrically controllable optical properties, comprising:

an electrical energy source having an output voltage U,

at least one functional element having electrically controllable optical properties, and

at least two supply lines, by means of which the electrical energy source and the functional element are connected,

wherein the output voltage U has an alternating voltage having

a frequency f of 40 Hz to 210 Hz,

a maximum amplitude U max of 24 V to 100 V,

a slope in the range of the output voltage U between −80% U max and 80% U max of 0.05*U max /100 μs to 0.1*U max /100 μs and in the range of the output voltage U between 80% U max and −80% U max of −0.05*U max /100 μs to −0.1*U max /100 μs,

wherein a thermometer is arranged on the functional element and the thermometer is coupled to the power supply.

2. The device according to claim 1 , wherein the functional element is planar.

3. The device according to claim 1 , wherein the functional element is a suspended particle device film or a polymer-dispersed liquid crystal film.

4. The device according to claim 1 , wherein the frequency f is from 45 Hz to 105 Hz.

5. The device according to claim 1 , wherein the maximum amplitude U max is from 50 V to 75 V.

6. The device according to claim 1 , wherein the slope in the range between −100% U max to −80% U max as well as between 80% U max to 100% U max is less than 0.05*U max /100 μs and between 100% U max to 80% U max as well as between −80% U max to −100% U max is greater than −0.05*U max /100 μs.

7. The device according to claim 1 , wherein the slope in the range between −90% U max and −80% U max as well as in the range from 80% U max to 90% U max is from 0.05*U max /100 μs to 0.1*U max /100 μs.

8. The device according to claim 1 , wherein the slope in the range between −100% U max and −90% U max as well as in the range from 90% U max to 100% U max is less than 0.05*U max /100 μs.

9. The device according to claim 1 , wherein the functional element is arranged inside a composite pane.

10. A method for controlling the device according to claim 1 , wherein

a) a temperature T is measured at the thermometer, and

b) the maximum amplitude U max of the output voltage U is adapted to the temperature, wherein from a certain threshold temperature T S as the temperature T increases at the thermometer, the maximum output voltage U max is lowered and up to a certain threshold temperature T S as the temperature T drops, the maximum output voltage U max is increased.

11. A method for controlling a device according to claim 1 , wherein the temperature T is measured at the thermometer and the maximum amplitude U max of the output voltage U is adapted as a function of the temperature T, wherein

for T<T S : U max =U max,k =constant at 50 V<U max,k <75 V and

for T>T S : 50 V−1.5 V/° C.*(T−T S )<U max <75 V−0.5 V/° C.*(T−T S )

and T S =constant at 40° C.<T S <60° C.

12. The method according to claim 11 , wherein

for T<T S : U max =U max,k =constant at 50 V<U max,k <75 V and

for T>T S : U max =U max,k +g (T−T S ) with −1.5 V/° C.<g<−0.5 V/° C.

and T S =constant at 40° C.<T S <60° C.

13. The method according to claim 11 , wherein

for T<T S : U max =U max,k =constant at 60 V<U max,k <70 V and

for T>T S : U max =U max,k +g (T−T S ) with

g=constant and −1.5 V/° C.<g<−0.5 V/° C. and

T S =constant at 40° C.<T S <60° C.

14. A method comprising utilizing a device according to claim 1 for controlling a functional element in a vehicle on water, on land, or in the air, or in an interior glazing or an exterior glazing of a building, as a sun screen or as a privacy screen.

15. The device according to claim 4 , wherein the frequency f is from 49 Hz to 69 Hz.

16. The device according to claim 5 , wherein the maximum amplitude U max is from 60 V to 70 V.

17. The device according to claim 9 , wherein the thermometer is arranged inside the composite pane.

18. The method according to claim 14 , wherein the device includes a windshield or a roof panel of a motor vehicle.