INORGANIC LIGHT-EMITTING-DIODE DISPLAYS WITH MULTI-ILED PIXELS

• US 20180226386A1
• Filed: 02/07/2018
• Published: 08/09/2018
• Est. Priority Date: 02/08/2017
• Status: Active Grant

• Current Assignee: X Display Company Technology Limited (Sensinnovat BVBA)
• Original Assignee: X-Celeprint Limited
• Inventors: Cok, Ronald S.
• Granted Patent: US 10,468,391 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 2224/18 High density interconnect [HDI] connectors; Manufacturing methods related thereto
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/13 the devices being of a type provided for in group H01L33/00
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

An inorganic light-emitting diode (iLED) display comprises a separate, independent, and distinct display substrate having a display area. A plurality of spatially separated pixels are distributed on or over the display substrate in the display area. Each pixel includes a group of two or more spatially separated iLEDs each having an iLED substrate separate, independent, and distinct from the display substrate. The two or more iLEDs are electrically connected in common to emit light together in response to a control signal. The pixels can include multiple groups of two or more iLEDs, each group of iLEDs can emit a different color of light to make a full-color display. The iLED display can be a passive-matrix display or include a pixel controller in an active-matrix configuration. The iLEDs and pixel controller can be provided on a pixel substrate disposed on the display substrate.

Claims

1. An inorganic light-emitting diode (iLED) display, comprising:

a display substrate having a display area; and

a plurality of spatially separated pixels distributed on or over the display substrate in the display area, wherein each pixel comprises a group of two or more spatially separated iLEDs each comprising an iLED substrate separate, independent, and distinct from the display substrate, the two or more iLEDs in the group electrically connected in common to emit light together in response to a control signal.

2. The iLED display of claim 1, wherein the two or more iLEDs in the group are connected in parallel.

3. The iLED display of claim 1, wherein the two or more iLEDs in the group are connected in serial.

4. The iLED display of claim 1, wherein the two or more iLEDs in the group emit a same color of light.

5. The iLED display of claim 1, wherein the two or more iLEDs in the group each emit a different color of light and the different color of light from each of the two or more iLEDs together is perceived to be white.

6. The iLED display of claim 1, wherein the plurality of spatially separated pixels are distributed in a regular array over the display area.

7. The iLED display of claim 1, wherein each pixel of the plurality of spatially separated pixels comprises a first group of two or more iLEDs and a second group of two or more iLEDs different from the first group, and the two or more iLEDs in the first group emit light of a different color than the two or more iLEDs in the second group.

8. The iLED display of claim 7, wherein the two or more iLEDs in the first group are interdigitated with the two or more iLEDs in the second group of the pixel.

9. The iLED display of claim 1, wherein each pixel of the plurality of spatially separated pixels comprises a first group of two or more iLEDs, a second group of two or more iLEDs, and a third group of two or more iLEDs, and wherein the first, second, and third groups are all different groups, and the first group emits red light, the second group emits green light, and the third group emits blue light.

10. The iLED display of claim 9, the two or more iLEDs of each of the first, second, and third groups are interdigitated with the two or more iLEDs of the other two groups in the pixel.

11. The iLED display of claim 1, wherein the iLED display is a full-color display.

12. The iLED display of claim 1, wherein the iLED display is a passive-matrix display.

13. The iLED display of claim 12, wherein each pixel of the plurality of spatially separated pixels comprises a pixel substrate on which the group of the two or more iLEDs is disposed, the pixel substrate disposed on the display substrate.

14. The iLED display of claim 13, wherein the display substrate comprises display substrate contact pads and the pixel substrate of each of the plurality of spatially separated pixels comprises pixel connection posts that are electrically connected to at least a portion of the contact pads and to the two or more iLEDs.

15. The iLED display of claim 1, wherein the iLED display is an active-matrix display.

16. The iLED display of claim 15, comprising a pixel controller comprising a controller substrate separate, independent, and distinct from the display substrate and the iLED substrate of each of the two or more iLEDs, that controls the two or more iLEDs to emit light in response to the control signal.

17. The iLED display of claim 16, wherein the controller substrate is disposed on the pixel substrate of a pixel of the plurality of spatially separated pixels.

18. The iLED display of claim 17, wherein the display substrate comprises contact pads and the pixel substrate comprises connection posts that are electrically connected to at least a portion of the contact pads and to the pixel controller.

19. The iLED display of claim 1, wherein the plurality of pixels comprises a first pixel and a second pixel spatially adjacent to the first pixel and wherein at least one of the two or more iLEDs of the first pixel is disposed between two of the two or more iLEDs of the second pixel so that the first pixel overlaps the second pixel over the display substrate.

20. The iLED display of claim 19, wherein the plurality of pixels comprises a third pixel spatially adjacent to the first pixel on a side of the first pixel opposite the second pixel and wherein at least one of the two or more iLEDs of the first pixel is disposed between two of the two or more iLEDs of the third pixel so that the first pixel overlaps the third pixel over the display substrate.

21. The iLED display of claim 20, wherein the first pixel has four sides and the plurality of pixels comprises a fourth pixel and a fifth pixel, each of the second, third, fourth and fifth pixels is spatially adjacent to a different one of the four sides, and wherein at least one of the two or more iLEDs of the first pixel is disposed between two of the two or more iLEDs of the second pixel, at least one of the two or more iLEDs of the first pixel is disposed between two of the two or more iLEDs of the third pixel, at least one of the two or more iLEDs of the first pixel is disposed between two of the two or more iLEDs of the fourth pixel, and at least one of the two or more iLEDs of the first pixel is disposed between two of the two or more iLEDs of the fourth pixel.

22. A method of making an iLED pixel, comprising:

providing an iLED source wafer comprising micro-transfer printable iLEDs;

providing a pixel substrate comprising two externally controlled control wires, wherein at least one control wire is a modulated control wire and the pixel substrate has lateral dimensions less than 1 cm;

micro-transfer printing two or more iLEDs from the iLED source wafer to the pixel substrate;

electrically connecting the two or more iLEDs in common; and

electrically connecting the two or more iLEDs to the two control wires.

23. The method of claim 22, comprising:

providing a controller source wafer comprising micro-transfer printable pixel controllers;

micro-transfer printing a pixel controller from the controller source wafer to the pixel substrate; and

electrically connecting the pixel controller to the two control wires and the two or more iLEDs.

24. A pixel source wafer, comprising:

a source wafer substrate comprising a plurality of sacrificial portions; and

a plurality of pixels each disposed entirely over a corresponding sacrificial portion of the plurality of sacrificial portions, each pixel comprising a pixel substrate, a group of two or more spatially separated iLEDs each comprising an iLED substrate separate, independent, and distinct from the pixel substrate and the source wafer substrate, the two or more iLEDs electrically connected in common to emit light together in response to a control signal.

25. The pixel source wafer of claim 24, wherein each pixel of the plurality of pixels comprises a pixel controller electrically connected to the two or more iLEDs to control the two or more iLEDs to emit light in response to the control signal.

26. The pixel source wafer of claim 25, wherein the pixel controller of each of the plurality of pixels comprises a broken or separated tether.

27. The pixel source wafer of claim 24, wherein the two or more iLEDs of each of the plurality of pixels each comprise a broken or separated tether.

28. The pixel source wafer of claim 24, wherein the corresponding sacrificial portion defines a gap between the pixel substrate and the source wafer such that one or more tethers connect each of the plurality of pixels disposed over the corresponding sacrificial portion to one or more anchor portions of the source wafer.

29. The pixel source wafer of claim 24, wherein each pixel of the plurality of pixels comprises one or more connection posts.