Organic light-emitting diode display with bottom shields
A display may have an array of organic light-emitting diode display pixels. Each display pixel may have a light-emitting diode that emits light under control of a drive transistor. Each display pixel may also have control transistors for compensating and programming operations. The array of display pixels may have rows and columns. Row lines may be used to apply row control signals to rows of the display pixels. Column lines (data lines) may be used to apply display data and other signals to respective columns of display pixels. A bottom conductive shielding structure may be formed below each drive transistor. The bottom conductive shielding structure may serve to shield the drive transistor from any electric field generated from the adjacent row and column lines. The bottom conductive shielding structure may be electrically floating or coupled to a power supply line.
1. A display, comprising:
a substrate;
a thin-film transistor formed over the substrate;
at least one buffer layer interposed between the thin-film transistor and the substrate;
a patterned metal layer that forms a conductive shielding structure, wherein the conductive shielding structure is formed beneath the buffer layer; and
a light-emitting diode coupled to the thin-film transistor, wherein the light-emitting diode and thin-film transistor are coupled in series between a first power supply line that supplies a positive power supply voltage and a second power supply line that supplies a ground power supply voltage, and wherein the patterned metal layer also forms a line selected from the group consisting of: the first power supply line and the second power supply line.
2. The display defined in claim 1 , wherein the at least one buffer layer comprises a buffer oxide layer.
3. The display defined in claim 2 further comprising:
a polyimide layer formed below the at least one buffer layer; and
a planarization layer formed below the at least one buffer layer, wherein the conductive shielding structure is interposed between the polyimide layer and the planarization layer.
4. The display defined in claim 3 , wherein the planarization layer is interposed between the conductive shielding structure and the at least one buffer layer.
5. The display defined in claim 4 , wherein the planarization layer is formed from a spin-on glass.
6. The display defined in claim 1 , wherein the line is further selected from the group consisting of: the first power supply line, the second power supply line, and an initialization line.
7. An electronic device display, comprising:
display pixels arranged in an array, wherein each display pixel in the array comprises:
a drive transistor;
a conductive shield formed below the drive transistor;
a planarization layer formed over the conductive shield, wherein the planarization layer is interposed between the conductive shield and the drive transistor; and
a polyimide layer formed under the conductive shield; and
a conductive path that conveys signals to the display pixels, wherein the conductive shield blocks the drive transistor from electric fields generated by the conductive path in at least one of the display pixels in the array.
8. The electronic device display defined in claim 7 , where each display pixel in the array further comprises a light-emitting diode coupled to the drive transistor.
9. The electronic device display defined in claim 7 , wherein the conductive shield is interposed between and in direct contact with the polyimide layer and the planarization layer.
10. The electronic device display defined in claim 9 , wherein the planarization layer is formed from a spin-on glass.
11. The electronic device display defined in claim 7 , wherein the conductive shield is formed from transparent conductive material.
12. The electronic device display defined in claim 7 , further comprising a power supply line, wherein the conductive shield and the power supply line are formed from a common metal layer.
13. The electronic device display defined in claim 7 , further comprising a line that is configured to provide a voltage signal, wherein the conductive shield and the line that is configured to provide the voltage signal are formed from a common metal layer.
14. A display, comprising:
a substrate;
a pixel that comprises a thin-film transistor formed over the substrate;
a polyimide layer formed on the substrate;
a conductive shielding structure formed on top of the polyimide layer directly below the thin-film transistor;
a planarization layer formed over the conductive shielding structure and the polyimide layer;
at least one buffer layer formed over the planarization layer; and
a line that provides an initialization voltage signal to the pixel, wherein the conductive shielding structure and the line that provides the initialization voltage signal to the pixel are formed from a patterned metal layer.
15. The display defined in claim 14 , further comprising a power supply line that provides a positive power supply voltage to the pixel, wherein the conductive shielding structure and the power supply line are formed from the patterned metal layer.
16. The display defined in claim 14 , further comprising a power supply line that provides a negative power supply voltage to the pixel, wherein the conductive shielding structure and the power supply line are formed from the patterned metal layer.