Glass panel comprising a liquid crystal film
A laminated automotive glazing including a PDLC film powered electrically by an AC current or a frequency lower than 100 Hz. The voltage varies non-sinusoidally, and a maximum of an effective voltage does not exceed 80 Vrms.
1. A laminated automotive glazing comprising:
a PDLC film powered electrically by an AC current having a frequency of from 20 Hz to less than 50 Hz, a voltage varying non-sinusoidally, a maximum of an effective voltage not exceeding 55 Vrms,
wherein a residual scattering in an actuated state is no higher than 5% for a temperature not exceeding 50° C., and
wherein power required to obtain the actuated state is no higher than 10 W/m 2 of PDLC film.
2. The glazing according to claim 1 , wherein the maximum of the effective voltage does not exceed 50 Vrms and a minimum effective voltage is 30 Vrms.
3. The glazing according to claim 1 , wherein a voltage variation has a trapezoidal profile.
4. The glazing according to claim 3 , wherein the voltage does not exceed 50 Vrms.
5. The glazing according to claim 3 , wherein the voltage variation has a trapezoidal shape with a rise time of 0.5 to 2 ms.
6. The glazing as claimed in claim 1 , wherein the frequency is no lower than 25 Hz.
7. The glazing according to claim 1 , wherein the residual scattering in the actuated state is no higher than 3% for a temperature not exceeding 60° C.
8. The glazing according to claim 1 , wherein a direct light transmission in the unactuated state is no higher than 1%.
9. The glazing according to claim 1 , wherein a direct light transmission in the unactuated state is no higher than 0.5%.
10. The glazing according to claim 1 , wherein power required to obtain the actuated state is no higher than 5 W/m 2 of PDLC film.
11. The glazing according to claim 1 , wherein a voltage variation has a square profile.
12. The glazing according to claim 1 , wherein the maximum of the effective voltage does not exceed 50 Vrms.
13. The glazing according to claim 1 , wherein the PDLC film is powered electrically by an AC current having a frequency of 30 Hz or lower.
14. The glazing according to claim 13 , wherein the PDLC film is powered by a current that does not exceed 200 mA.
15. An automotive roof comprising:
two glass sheets;
a first interlayer sheet; and
a PDLC film powered electrically by an AC current having a frequency of from 20 Hz to less than 50 Hz, a voltage varying non-sinusoidally, and a maximum of an effective voltage not exceeding 50 Vrms,
wherein a residual scattering in an actuated state is no higher than 5% for a temperature not exceeding 50° C., and
wherein power required to obtain the actuated state is no higher than 10 W/m 2 of PDLC film.
16. The glazing according to claim 15 , wherein a voltage variation has a trapezoidal profile.
17. The glazing according to claim 15 , further comprising second and third interlayer sheets,
wherein the second interlayer sheet defines a housing for the PDLC film.
18. The glazing according to claim 15 , wherein the minimum effective voltage is 30 Vims.