Display device comprising a light guide
View Patent ↗A display device comprises row ( 5 ) and column ( 6 ) electrodes and a movable element ( 3 ) and means ( 17 ) for supplying voltages to the electrodes, wherein the row electrodes are situated on the movable element. The means supply, in operation, such voltages to the electrodes that use is made of the memory effect of the movable element. More in particular, the row electrodes are, in operation, supplied with “on”, “off” and “hold” voltages and the column electrodes are supplied with “hold” and ‘off’-voltages. Application of “on” voltages turns on the pixels in a row, simultaneous application of “off” voltages turns a pixel off. Application of a “hold” voltage to either one of the electrodes preserves the status of the pixel.
1. A display device, comprising:
a light guide having first electrodes disposed thereon;
a substrate confronting and spaced apart from the light guide, said substrate having a common electrode disposed thereon;
a movable element disposed between the light guide and the substrate, said movable element having second electrodes disposed thereon; and
a control unit adapted to apply voltages to the first, second, and common electrodes to bring the movable element into contact with the light guide.
2. The display device of claim 1 , wherein the substrate includes an insulating layer covering the common electrode.
3. The display device of claim 1 , wherein the movable element comprises a first material and has a layer of a second material disposed thereon, wherein an elastic modulus of the second material is greater than an elastic modulus of the first material.
4. The display device of claim 1 , wherein the second electrodes comprise a transparent material, and wherein the common electrode comprises a reflective material.
5. The display device of claim 1 , further comprising a color determining element, and wherein in response to the movable element contacting the light guide, light from the light guide is provided to the color determining element.
6. The display device of claim 5 , wherein the color determining element is one of a color filter and a phosphor.
7. A display device, comprising:
a light guide having a first electrode;
a common electrode spaced apart from the light guide;
a movable element having a second electrode disposed between the first electrode and the common electrode; and
means for applying voltages to the first, second, and common electrodes to bring the movable element into contact with the light guide.
8. The display device of claim 7 , wherein the common electrode is reflective.
9. The display device of claim 7 , wherein the movable element comprises a first material and has a layer of a second material disposed thereon, wherein an elastic modulus of the second material is greater than an elastic modulus of the first material.
10. The display device of claim 7 , further comprising a color determining element, and wherein in response to the movable element contacting the light guide, light from the light guide is provided to the color determining element.
11. The display device of claim 7 , wherein the color determining element comprises a color phosphor.
12. The display device of claim 7 , wherein the color determining element comprises a color filter.
13. A method of displaying an image on a display device including a light guide having a plurality of first electrodes, a substrate having a common electrode and being spaced apart from the light guide, and a movable element having a plurality of second electrodes and being disposed between the light guide and the substrate, said method comprising:
providing light to the light guide; and
applying voltages to the first, second, and common electrodes to bring the movable element into contact with the light guide at selected locations such that light emerges from the light guide at the selected locations to display an image.
14. The method of claim 13 , further comprising:
providing color filters at crossing locations where the first and second electrodes cross; and
passing the light emerging from the light guide through the color filters.
15. The method of claim 13 , further comprising:
providing color phosphors at crossing locations where the first and second electrodes cross; and
exciting the color phosphors with the light emerging from the light guide.
16. The method of claim 13 , further comprising reflecting the light emerging from the light guide at the selected locations out of the device in one direction using the common electrode as a reflector.
17. The method of claim 13 , wherein applying voltages to the first, second, and common electrodes to bring the movable element into contact with the light guide at selected locations, comprises:
applying a first set of voltages having a lower and an upper value to the first electrodes, and
applying a second set of voltages having a lower, a middle and an upper value to one of the second electrodes crossing the first electrodes at crossing areas.
18. The method of claim 17 , wherein only simultaneous application of the upper value to the second electrode and of the lower value to the first electrodes brings the movable element into contact with the light guide at the crossing areas.
19. The method of claim 17 , wherein in operation the upper value of the second set of voltages is equal to the voltage applied to the common electrode.
20. The method of claim 17 , wherein only simultaneous application of the lower value to the second electrode and of the upper value to the first electrodes moves the movable element away from contact with the light guide at the crossing areas.