Electro-static discharge and electric overstress protection strategy for micro-chip array on panel

• US 9,966,000 B2
• Filed: 09/24/2015
• Issued: 05/08/2018
• Est. Priority Date: 01/16/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Fan, Xiaofeng, Bibl, Andreas, Sakariya, Kapil V., Nauta, Tore
• Primary Examiner(s): Adediran, Abdul-Samad A
• Application Number:
  US14/864,798
• Publication Number:
  US 20160210895A1
• Time in Patent Office: 957 Days
• Field of Search: 257 43, 257 59, 324555, 345 98, 345212, 345175, 348 87, 349 40, 361748
• CPC Class Codes: G09G 2330/04 Display protection
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 27/0248 for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H02H 9/046 responsive to excess voltage appearing at terminals of integrated circuits protection by specific structural integration design H01L27/0248

Abstract

A display system includes an array of light emitting diodes (LEDs), first and second driver chips, and one or more protection chips on a display substrate. The first and second driver chips are to drive a first group of LEDs of the array of LEDs and a second group of LEDs of the array of LEDs, respectively. Each protection chip includes one or more electro-static discharge (ESD) protection devices to assist with protecting the driver chips from damage caused by an ESD event. In one embodiment, each ESD protection device is connected between one or more signal lines, one or more power supply voltage lines, and an electrical ground line of the display substrate. In one embodiment, at least one protection chip comprises one or more electric overstress (EOS) protection devices to assist with protecting the driver chips from damage caused by an EOS event.

Claims

1. A display system comprising:

a display substrate;

an array of light emitting diodes (LEDs) on the display substrate;

a first driver chip bonded to the display substrate, the first driver chip to drive a first group of LEDs of the array of LEDs;

a second driver chip bonded to the display substrate, the second driver chip to drive a second group of LEDs of the array of LEDs;

a plurality of protection chips bonded to the display substrate, wherein each protection chip of the plurality of protection chips includes one or more electro-static discharge (ESD) protection devices, wherein;

the plurality of protection chips includes a first protection chip and a second protection chip that are directly connected to one another through one or more signal lines of the display substrate, one or more power supply voltage lines of the display substrate, and an electrical ground line of the display substrate, and an inter-protection chip line interposed between each of the plurality of protection chips and directly connecting only the plurality of protection chips to each other in order to operate the first and second protection chips in parallel; and

the first protection chip is to assist with protecting the first and second driver chips from damage caused by an ESD event.

2. The display system of claim 1, wherein:

at least one of the first driver chip, the second driver chip, the first protection chip, or one or more of the LEDs in the array of LEDs is a micro device.

3. The display system of claim 1, wherein:

each protection chip of the plurality of protection chips further comprises one or more electric overstress (EOS) protection devices; and

the first protection chip is to assist with protecting the first and second driver chips from damage caused by an EOS event.

4. The display system of claim 1, further comprising:

a flex cable connected to the display substrate, the flex cable including a timing controller (TCON), wherein;

the flex cable is connected to the signal lines, the power supply lines, and the electrical ground line;

the flex cable is located at an edge of a first contact ledge of the display substrate, and

a first protection chip is bonded to the display substrate at a location between a display region of the display substrate and the first contact ledge.

5. The display system of claim 4, further comprising:

a first data driver connected to the display substrate through the flex cable, the first data driver to provide a first display driver signal to the first and second driver chips, wherein;

the first data driver is mounted on the flex cable;

the first data driver is to receive a first input signal from one or more of the signal lines, and the first input signal is to be processed by the first data driver into the first display driver signal.

6. The display system of claim 5, further comprising:

a third driver chip bonded to the display substrate the third driver chip to drive a third group of LEDs of the array of LEDs;

wherein;

the first and second driver chips are arranged on the display substrate as a first column,

the first and third driver chips are arranged on the display substrate as a first row,

the third driver chip is arranged on the display substrate as a second column,

the second driver chip is arranged on the display substrate as a second row,

the second protection chip is to assist with protecting the third driver chip from an ESD event, and

the second protection chip is bonded to the display substrate at a location between the display region of the display substrate and the first contact ledge.

7. The display system of claim 6, wherein:

at least one of the third driver chip or the second protection chip is a micro device.

8. The display system of claim 6, further comprising:

a second data driver connected to the display substrate through the flex cable, the second data driver to provide a second display driver signal to the third driver chip, wherein;

the second data driver is mounted on the flex cable;

the second data driver is to receive a second input signal from one or more of the signal lines,

the second input signal is to be processed by the second data driver into the second display driver signal, and

the second display driver signal is different from the first display driver signal.

9. The display system of claim 8, further comprising:

a scan driver on the display substrate, the scan driver to select at least one of the first row or the second row via one or more selection signals provided through one or more of the signal lines, wherein;

the scan driver is bonded to the display substrate at a location between a display region of the display substrate and a second contact ledge of the display substrate;

each of the first and second data drivers is to provide the respective display driver signals to the respective driver chips when the respective driver chips are in the selected row.

10. The display system of claim 9, wherein:

the plurality of protection chips includes a third protection chip bonded to the display substrate, wherein;

the second protection chip and the third protection chip are directly connected to one another through one or more of the signal lines, one or more of the power supply voltage lines, and the electrical ground line,

the third protection chip is to assist with protecting the scan driver from an ESD event, and

the third protection chip is bonded to the display substrate at a location between the display region of the display substrate and the first contact ledge.

11. The display system of claim 10, wherein:

at least one protection chip of the plurality of protection chips further comprises a small-scale protection device.

12. The display system of claim 10, wherein:

at least two of the driver chips are connected to each other via an inter-driver-chip signal line, and

at least one of the driver chips further comprises a small-scale protection device.

13. The display system of claim 10, wherein:

one or more signals are provided, via the signal lines, to at least one of the protection chips of the plurality of protection chips prior to the one or more signals being provided to the respective driver chips; and

one or more power supply voltages are provided, via the power supply voltage lines, to at least one of the protection chips of the plurality of protection chips prior to the one or more power supply voltages being provided to the respective driver chips.

14. A method comprising:

bonding a plurality of protection chips to a receiving display substrate, each of the protection chips comprises one or more electro-static discharge (ESD) protection devices;

bonding an array of driver chips to the receiving display substrate;

transferring an array of light emitting diodes (LEDs) onto the receiving display substrate, wherein;

each of the driver chips is to drive at least one of the LEDs,

each of the protection chips is to assist with protecting at least one of the driver chips from an ESD event;

the plurality of protection chips includes a first protection chip and a second protection chip that are directly connected to one another through one or more signal lines of the receiving display substrate, one or more power supply voltage lines of the receiving display substrate, and an electrical ground line of the receiving display substrate, and an inter-protection chip line interposed between each of the plurality of protection chips and directly connecting only the plurality of protection chips to each other in order to operate the first and second protection chips in parallel; and

the plurality of protection chips are connected to the array of driver chips via one or more of the signal lines, one or more of the power supply voltage lines, and the electrical ground line.

15. The method of claim 14, wherein:

at least one of the protection chips further comprises one or more electric overstress (EOS) protection devices;

the at least one protection chip having the one or more EOS device is to assist with protecting at least one of the driver chips from an EOS event.

16. The method of claim 14, wherein:

the bonding of plurality of protection chips, the bonding of the array of driver chips, and the transferring of the array of LEDs is performed in one or more batches.

17. The method of claim 14, further comprising:

connecting a flex cable to the receiving display substrate, wherein;

the flex cable includes a timing controller (TCON),

the flex cable is connected to the signal lines, the power supply lines, and the electrical ground line;

the flex cable is located at an edge of a contact ledge of the receiving display substrate;

connecting at least one of the protection chips to the flex cable, wherein;

the at least one protection chip connected to the flex cable is bonded to the receiving display substrate at a location between a display region of the receiving display substrate and the edge of the contact ledge.

18. The method of claim 14, further comprising:

connecting a discharge circuit to the display substrate, wherein the discharge circuit is connected to the display substrate prior to the plurality of protection chips, the array of driver chips, and the array of LEDs being bonded or transferred onto the display substrate;

connecting a flex cable to the discharge circuit, wherein the flex cable is connected to the discharge circuit prior to being connected to the display substrate;

discharging, by the discharge circuit, the display substrate and the flex cable until potentials of the display substrate and the flex cable are at least approximately equal;

connecting the flex cable to the display substrate; and

disconnecting the flex cable and the display substrate from the discharge circuit.

19. The method of claim 14, further comprising:

providing one or more signals, via the signal lines, to the plurality of protection chips prior to the one or more signals being provided to the array of driver chips; and

providing one or more power supply voltages, via the power supply voltage lines, to the plurality of protection chips prior to the one or more power supply voltages being provided to the array of driver chips.

20. The method of claim 14, wherein at least one of one or more driver chips of the array of driver chips, one or more protection chips of the protection chips plurality of protection chips, or one or more LEDs of the array of the LEDs is a micro device.