| CPC G02F 1/133514 (2013.01) [G02F 1/133606 (2013.01); G02F 1/133626 (2021.01); G02F 1/133769 (2021.01)] | 7 Claims |
|
1. A switchable light filter (5), comprising
at least one first optical element (1) comprising
a plurality of light-absorbing transition dipole moments (15) formed by dichroitic dyes, in the case of which the dye mass fraction is more than 1%, arranged in a layer with a thickness of from 0.2 microns to 50 microns, including the limits,
wherein, in at least a first state, a majority of the plurality of light-absorbing transition dipole moments (15) is aligned with a tolerance of maximally 5° parallel to a first direction (16),
wherein the first direction that is selectable for the at least one first optical element (1), or the majority of the plurality of light-absorbing transition dipole moments (15) fluctuates with respect to the first direction (16),
wherein the first direction (16) is arranged at an angle α as measured against a perpendicular bisector (6) of the at least one first optical element (1), whereby the angle α is measured in a selectable first plane, containing the perpendicular|bisector (6),
so that light, incident into the at least one first optical element (1) and having a direction of incidence and a polarization state, is transmittable or at least partially absorbable as a function of the direction of incidence with respect to the at least one first optical element (1) and the polarization state,
a liquid crystal layer (3), which is arranged behind or in front of the at least one first optical element (1) in a viewing direction and onto which a first electric field (EF 1) or a second electric field (EF2) is applied acts and which, as a function thereof, influences the polarization state of light passing through the liquid crystal layer (3),
wherein, when the liquid crystal layer (3) is arranged in front of the at least one first optical element (1) in the viewing direction, a first linear polarization filter (X), lies in front of the liquid crystal layer (3) in the viewing direction,
such that transmission properties of the switchable light filter (5) differ between a first operating mode B1, in which the first electric field (EF1) is applied, and a second operating mode B2, in which the second electric field (EF2) is applied with a field strength equal to 0 V/μm, wherein the respective relative transmission in the first and second operating modes B1 and B2 at one or more points on switchable light filter (5) except for a selectable tolerance up to 5% Is, in each case, described by a transmission TB1(β) for the first operating mode B1 or TB2(β) for the second operating mode B2, respectively, which are each standardized such that the following applies for the values of the transmission Tp1(α)=1 and Tg2(α)=1,
in that, when light
is incident into the at least one first optical element (1) at angles (8) with α−60°≤β≤α−40° or α+40°≤β≤α+60°, in the first operating mode B1, in which the first electric field (EF1) is applied, the s-polarized proportion of the light is transmitted by the switchable light filter (5) to a standardized transmission value TB1(β)≥20.25, and
is incident into the at least one first optical element (1) at angles (β) with α−60°≤β≤α−40° or α+40°≤β≤α+60°, in the second operating mode B2, in which the second electric field (EF2) is applied, the p-polarized proportion of the light (14) is transmitted by the switchable light filter (5) to maximally a standardized transmission value TB2(β)≤0.2.
|