Privacy films for electronic displays
The present disclosure is drawn to privacy films for electronic displays. In one example, a privacy film for an electronic display can include a louver film. The louver film can include: a plurality of high refractive index slats with a refractive index of about 1.5 to about 3 and having a trapezoidal cross section narrowing toward a viewer side of the louver film; and a plurality of low refractive index slats between the high refractive index slats, having a refractive index less than the refractive index of the high refractive index slats by about 0.1 to about 2. An electrophoretic ink can be optically associated with the low refractive index slats, including opaque particles that are electrically mobile to cause modification of light transmission therethrough. A first and second transparent electrode film can be on a viewer side and a rear side of the electrophoretic ink, respectively.
1. A privacy film for an electronic display comprising:
a louver film comprising:
a plurality of high refractive index slats having a trapezoidal cross section narrowing toward a viewer side of the louver film, wherein the high refractive index slats have a refractive index of 1.5 to 3,
a plurality of low refractive index slats between the high refractive index slats, wherein the low refractive index slats have a refractive index less than the refractive index of the high refractive index slats by 0.1 to 2, and
an electrophoretic ink optically associated with the low refractive index slats, wherein the electrophoretic ink includes positively charged opaque particles that are electrically mobile;
a first transparent electrode film on a viewer side of the electrophoretic ink; and
a second transparent electrode film on a rear side of the electrophoretic ink;
wherein movement of the positively charged opaque particles causes modification of light transmission through the electrophoretic ink when a voltage is applied or modified across i) the first transparent electrode film and ii) the second transparent electrode film.
2. The privacy film of claim 1 , wherein the positively charged opaque particles in the electrophoretic ink move to permit the light transmission through the electrophoretic ink of light transmitted from the low refractive index slats when the voltage is applied or modified.
3. The privacy film of claim 1 , wherein the electrophoretic ink is positioned within the low refractive index slats.
4. The privacy film of claim 1 , wherein the electrophoretic ink is positioned as a separate layer on the viewer side of the low refractive index slats.
5. The privacy film of claim 1 , wherein the positively charged opaque particles comprise a black pigment.
6. The privacy film of claim 1 , wherein the electrophoretic ink further comprises negatively charged transparent particles.
7. The privacy film of claim 6 , wherein the negatively charged transparent particles and the positively charged opaque particles rearrange with respect to one another when the voltage is applied or modified across the first and second transparent electrode films.
8. The privacy film of claim 1 , wherein the trapezoidal cross section of the high refractive index slats has an acute angle from 85° to 88°.
9. The privacy film of claim 1 , wherein the high refractive index slats comprise polyethylene terephthalate, polyethylene, polycarbonate, poly(acrylic acid), or combinations thereof.
10. The privacy film of claim 1 , further comprising a power supply connected to the first transparent electrode film and the second transparent electrode film through a switch.
11. An electronic display comprising:
a backlight unit;
a liquid crystal display panel on a viewer side of the backlight unit; and
a privacy film on a viewer side of the liquid crystal display panel, the privacy film comprising:
a louver film comprising:
a plurality of high refractive index slats having a trapezoidal cross section narrowing toward a viewer side of the louver film, wherein the high refractive index slats have a refractive index of 1.5 to 3,
a plurality of low refractive index slats between the high refractive index slats, wherein the low refractive index slats have a refractive index less than the refractive index of the high refractive index slats by 0.1 to 2, and
an electrophoretic ink optically associated with the low refractive index slats, wherein the electrophoretic ink includes positively charged opaque particles that are electrically mobile;
a first transparent electrode film on a viewer side of the electrophoretic ink; and
a second transparent electrode film on a rear side of the electrophoretic ink;
wherein movement of the positively charged opaque particles causes modification of light transmission through the electrophoretic ink when a voltage is applied or modified across i) the first transparent electrode film and ii) the second transparent electrode film.
12. The electronic display of claim 11 , wherein the privacy film is oriented such that the high refractive index slats and low refractive index slats extend in a vertical direction with respect to a viewer.
13. The electronic display of claim 11 , wherein the electronic display is part of an electronic device and the electronic device comprises a connection to the first transparent electrode film and the second transparent electrode film to apply or modify the voltage across the first transparent electrode film and the second transparent electrode film.
14. A method of making a privacy film for an electronic display comprising:
forming a louver film by placing a plurality of high refractive index slats having a trapezoidal cross section narrowing toward a viewer side of the louver film, wherein the high refractive index slats have a refractive index of 1.5 to 3, and placing a plurality of low refractive index slats between the high refractive index slats, wherein the low refractive index slats have a refractive index less than the refractive index of the high refractive index slats by 0.1 to 2;
optically associating an electrophoretic ink with the low refractive index slats, wherein the electrophoretic ink comprises positively charged opaque particles that are electrically mobile;
placing a first transparent electrode film on a viewer side of the electrophoretic ink; and
placing a second transparent electrode film on a rear side of the electrophoretic ink;
wherein movement of the positively charged opaque particles causes modification of light transmission through the electrophoretic ink when a voltage is applied or modified across i) the first transparent electrode film and ii) the second transparent electrode film.
15. The method of claim 14 , wherein optically associating the electrophoretic ink comprises placing the electrophoretic ink within the low refractive index slats or in a separate layer on the viewer side of the low refractive index slats.
16. The privacy film of claim 6 , wherein the positively charged opaque particles comprise a black pigment, and wherein the negatively charged transparent particles comprise a transparent material selected from the group consisting of polycarbonate particles, poly(methyl methacrylate) particles, glass particles, and a combination thereof.
17. The electronic display of claim 11 , wherein the positively charged opaque particles comprise a black pigment, and wherein the negatively charged transparent particles comprise a transparent material selected from the group consisting of polycarbonate particles, poly(methyl methacrylate) particles, glass particles, and a combination thereof.
18. The method of claim 14 , wherein the positively charged opaque particles comprise a black pigment, and wherein the negatively charged transparent particles comprise a transparent material selected from the group consisting of polycarbonate particles, poly(methyl methacrylate) particles, glass particles, and a combination thereof.