Patent ID: 12254799

DETAILED DESCRIPTION

When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment”, “an embodiment”, or “some embodiments” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Use of the term “approximately” or “near” should be understood to mean including close to a target (e.g., design, value, amount), such as within a margin of any suitable or contemplatable error (e.g., within 0.1% of a target, within 1% of a target, within 5% of a target, within 10% of a target, within 25% of a target, and so on). Additionally, as used herein, a “malfunctioning light emitting diode” may refer to a light emitting diode (LED) that is not operating and/or functioning as expected. For example, a malfunctioning LED may not emit light at an intended brightness level. As another example, the malfunctioning LED may not turn on to emit any brightness or may continue to emit at a brightness level for longer or shorter than an intended time period. In yet another example, the malfunctioning LED may include an LED that is misplaced on the display (e.g., backplane of the display) and/or that is not properly bonded to the display. Also, as used herein, a “global pad” may refer to a pad of metal or the like material, that is connected to or a part of a display driver circuitry. The global pad may connect and enable interfacing between components, circuitry, input connections, and/or output connections throughout the entire display (e.g., global unidirectional or bidirectional communication). For example, the global pad may connect drivers, LEDs, power sources, and so forth. In some embodiments, the global pad may facilitate communication in a particular region or a particular pixel rather than globally. The global pad may be connected to the display circuitry via pins, bonding wires, and the like.

The present disclosure provides techniques for testing and/or repairing LEDs of a display. Some electronic displays may include multiple LEDs, for example, to drive the LEDs with less current to reduce power consumption of the display. In such display architectures, some of the multiple LEDs may function as redundant LEDs. As such, a malfunctioning LED may be replaced by one of the functioning multiple LEDs. For example, if a driver drives two LEDs and one no longer functions as intended, the driver may instead drive only the working LED. In this example, to illuminate at the same level as other LEDs on the display, the driver may drive the working LED with twice the amount of current.

As such, the systems and methods described herein disclose efficiently driving LEDs, identifying malfunctioning LEDs, repairing LEDs, or a combination thereof. In some embodiments, drivers may drive first LEDs and second LEDs of multiple rows of LEDs of a display. Display circuitry may test a first LED of each of the rows of LEDs by causing a driver to drive the first LEDs with current. The driver may subsequently drive a second LED of each of the rows of LEDs by driving the LEDs. In this manner, the display circuitry may identify which of the LEDs may be malfunctioning (e.g., not emitting light when driven). To repair the display, a laser device may imprint metal (e.g., moly) to short the malfunctioning LEDs.

In some embodiments, the LEDs may be shorted (e.g., pre-shorted) prior to testing. An electroluminescence test may be performed to identify malfunctioning LEDs of the display. After identifying the malfunctioning LEDs, a laser device may remove the short for the functioning LEDs (e.g., open up shorts) while the malfunctioning LEDs remain shorted. In additional or alternative embodiments, the drivers and LEDs may connect to a global pad. Specifically, the global pad may short cathodes of the first LEDs and the anodes of the second LEDs. The display circuitry may apply specified voltages (e.g., high or low voltages) to drive the first and second LEDs to determine whether the LEDs are functioning as intended. A laser device or the like may short the malfunctioning LEDs. Furthermore, in some embodiments, the LEDs may connect to a series of switches that are configurable (e.g., via closing or opening the switch) to connect the LEDs to current source and/or a decoder. The switches may be closed (e.g., turned on) to test each of the LEDs individually. After testing the LEDs, the malfunctioning LEDs may be shorted.

With the foregoing in mind,FIG.1illustrates an electronic device10according to an embodiment of the present disclosure may include, among other things, one or more processor(s)12, memory14, nonvolatile storage16, a display18, input structures22, an input/output (I/O) interface24, a network interface26, a power source28, and a transceiver30. The various functional blocks shown inFIG.1may include hardware elements (including circuitry), software elements (including computer code stored on a computer-readable medium) or a combination of both hardware and software elements. It should be noted thatFIG.1is merely one example of a particular implementation and is intended to illustrate the types of components that may be present in electronic device10.

By way of example, the electronic device10may represent a block diagram of the notebook computer depicted inFIG.2, the handheld device depicted inFIG.3, the handheld device depicted inFIG.4, the desktop computer depicted inFIG.5, the wearable electronic device depicted inFIG.6, or similar devices. It should be noted that the processor(s)12and other related items inFIG.1may be generally referred to herein as “data processing circuitry.” Such data processing circuitry may be embodied wholly or in part as software, hardware, or any combination thereof. Furthermore, the processor(s)12and other related items inFIG.1may be a single contained processing module or may be incorporated wholly or partially within any of the other elements within the electronic device10.

In the electronic device10ofFIG.1, the processor(s)12may be operably coupled with a memory14and a nonvolatile storage16to perform various algorithms. For example, the algorithms may include ones for current-voltage driving, current-voltage driving with active discharging of light emitting diodes (LEDs), current-voltage driving for LEDs having varying forward operating voltages, and so forth. Such algorithms or instructions executed by the processor(s)12may be stored in any suitable article of manufacture that includes one or more tangible, computer-readable media. The tangible, computer-readable media may include the memory14and/or the nonvolatile storage16, individually or collectively, to store the algorithms or instructions. The memory14and the nonvolatile storage16may include any suitable articles of manufacture for storing data and executable instructions, such as random-access memory, read-only memory, rewritable flash memory, hard drives, and optical discs. In addition, programs (e.g., an operating system) encoded on such a computer program product may also include instructions that may be executed by the processor(s)12to enable the electronic device10to provide various functionalities.

In certain embodiments, the display18may be a liquid crystal display (LCD), which may facilitate users to view images generated on the electronic device10. In some embodiments, the display18may include a touch screen, which may facilitate user interaction with a user interface of the electronic device10. Furthermore, it should be appreciated that, in some embodiments, the display18may include one or more light-emitting diode (LED) displays, organic light-emitting diode (OLED) displays, active-matrix organic light-emitting diode (AMOLED) displays, or some combination of these and/or other display technologies. Often, one or more of the LEDs may not operate or function as expected (e.g., malfunctioning LEDs), for example, due to a drop in power or current levels required for the LED to turn on or emit an expected brightness. Briefly, and as will be described in detail herein, the display18and/or an external electronic device10may include circuitry with a global pad connected to microdrivers driving the LEDs to identify a portion of malfunctioning LEDs based on the connections and/or comparing measured electrical potentials for LEDs based on known electrical potentials of the LEDs. To repair the malfunctioning LEDs, the display18and/or the external electronic device10may include circuitry to cause another electronic device (e.g., a laser device) to short the malfunctioning LEDs (e.g., using laser-deposited metal or to open pre-shorts using laser cutting for pre-shorted LEDs that are properly functioning). In this manner, after the display10is turned on, circuitry of an electronic device10may determine malfunctioning LEDs. Moreover, the malfunctioning LEDs may be repaired (e.g., by using the redundant LEDs) to reduce or prevent perceivable unexpected displays on the display (e.g., no luminance on a region of the display18).

The input structures22of the electronic device10may enable a user to interact with the electronic device10(e.g., pressing a button to increase or decrease a volume level). The I/O interface24may enable the electronic device10to interface with various other electronic devices, as may the network interface26. The network interface26may include, for example, one or more interfaces for a personal area network (PAN), such as a BLUETOOTH® network, for a local area network (LAN) or wireless local area network (WLAN), such as an 802.11x WI-FI® network, and/or for a wide area network (WAN), such as a 3rdgeneration (3G) cellular network, universal mobile telecommunication system (UMTS), 4thgeneration (4G) cellular network, long term evolution (LTE®) cellular network, long term evolution license assisted access (LTE-LAA) cellular network, 5thgeneration (5G) cellular network, and/or New Radio (NR) cellular network. In particular, the network interface26may include, for example, one or more interfaces for using a Release-15 cellular communication standard of the 5G specifications that include the millimeter wave (mmWave) frequency range (e.g., 24-300 GHz). The transceiver30of the electronic device10, which includes the transmitter and the receiver, may allow communication over the aforementioned networks (e.g., 5G, Wi-Fi, LTE-LAA, and so forth).

The network interface26may also include one or more interfaces for, for example, broadband fixed wireless access networks (e.g., WIMAX®), mobile broadband Wireless networks (mobile WIMAX®), asynchronous digital subscriber lines (e.g., ADSL, VDSL), digital video broadcasting-terrestrial (DVB-T®) network and its extension DVB Handheld (DVB-H®) network, ultra-wideband (UWB) network, alternating current (AC) power lines, and so forth.

In some embodiments, the electronic device10communicates over the aforementioned wireless networks (e.g., WI-FI®, WIMAX®, mobile WIMAX®, 4G, LTE®, 5G, and so forth) using the transceiver30. The transceiver30may include circuitry useful in both wirelessly receiving the reception signals at the receiver and wirelessly transmitting the transmission signals from the transmitter (e.g., data signals, wireless data signals, wireless carrier signals, radio frequency signals). Indeed, in some embodiments, the transceiver30may include the transmitter and the receiver combined into a single unit, or, in other embodiments, the transceiver30may include the transmitter separate from the receiver. The transceiver30may transmit and receive radio frequency signals to support voice and/or data communication in wireless applications such as, for example, PAN networks (e.g., BLUETOOTH®), WLAN networks (e.g., 802.11x WI-FT®), WAN networks (e.g., 3G, 4G, 5G, NR, and LTE® and LTE-LAA cellular networks), WIMAX® networks, mobile WIMAX® networks, ADSL and VDSL networks, DVB-T® and DVB-H® networks, UWB networks, and so forth. As further illustrated, the electronic device10may include the power source28. The power source28may include any suitable source of power, such as a rechargeable lithium polymer (Li-poly) battery and/or an alternating current (AC) power converter.

In certain embodiments, the electronic device10may take the form of a computer, a portable electronic device, a wearable electronic device, or other type of electronic device. Such computers may be generally portable (such as laptop, notebook, and tablet computers), or generally used in one place (such as desktop computers, workstations, and/or servers). In certain embodiments, the electronic device10in the form of a computer may be a model of a MacBook®, MacBook® Pro, MacBook Air®, iMac®, Mac® mini, or Mac Pro® available from Apple Inc. of Cupertino, California By way of example, the electronic device10, taking the form of a notebook computer10A, is illustrated inFIG.2in accordance with one embodiment of the present disclosure. The depicted notebook computer10A may include a housing or enclosure36, a display18, input structures22, and ports of an I/O interface24. In one embodiment, the input structures22(such as a keyboard and/or touchpad) may be used to interact with the computer10A, such as to start, control, or operate a graphical user interface (GUI) and/or applications running on computer10A. For example, a keyboard and/or touchpad may allow a user to navigate a user interface and/or an application interface displayed on display18.

FIG.3depicts a front view of a handheld device10B, which represents one embodiment of the electronic device10. The handheld device10B may represent, for example, a portable phone, a media player, a personal data organizer, a handheld game platform, or any combination of such devices. By way of example, the handheld device10B may be a model of an iPhone® available from Apple Inc. of Cupertino, California. The handheld device10B may include an enclosure36to protect interior components from physical damage and/or to shield them from electromagnetic interference. The enclosure36may surround the display18. The I/O interfaces24may open through the enclosure36and may include, for example, an I/O port for a hardwired connection for charging and/or content manipulation using a standard connector and protocol, such as the Lightning connector provided by Apple Inc. of Cupertino, California, a universal serial bus (USB), or other similar connector and protocol.

The input structures22, in combination with the display18, may allow a user to control the handheld device10B. For example, the input structures22may activate or deactivate the handheld device10B, navigate user interface to a home screen, a user-configurable application screen, and/or activate a voice-recognition feature of the handheld device10B. Other input structures22may provide volume control, or may toggle between vibrate and ring modes. The input structures22may also include a microphone that may obtain a user's voice for various voice-related features, and a speaker that may enable audio playback and/or certain phone capabilities. The input structures22may also include a headphone input that may provide a connection to external speakers and/or headphones.

FIG.4depicts a front view of another handheld device10C, which represents another embodiment of the electronic device10. The handheld device10C may represent, for example, a tablet computer, or one of various portable computing devices. By way of example, the handheld device10C may be a tablet-sized embodiment of the electronic device10, which may be, for example, a model of an iPad® available from Apple Inc. of Cupertino, California.

Turning toFIG.5, a computer10D may represent another embodiment of the electronic device10ofFIG.1. The computer10D may be any computer, such as a desktop computer, a server, or a notebook computer, but may also be a standalone media player or video gaming machine. By way of example, the computer10D may be an iMac®, a MacBook®, or other similar device by Apple Inc. of Cupertino, California. It should be noted that the computer10D may also represent a personal computer (PC) by another manufacturer. A similar enclosure36may be provided to protect and enclose internal components of the computer10D, such as the display18. In certain embodiments, a user of the computer10D may interact with the computer10D using various peripheral input structures22, such as the keyboard22A or mouse22B (e.g., input structures22), which may connect to the computer10D.

Similarly,FIG.6depicts a wearable electronic device10E representing another embodiment of the electronic device10ofFIG.1that may be configured to operate using the techniques described herein. By way of example, the wearable electronic device10E, which may include a wristband43, may be an Apple Watch® by Apple Inc. of Cupertino, California. However, in other embodiments, the wearable electronic device10E may include any wearable electronic device such as, for example, a wearable exercise monitoring device (e.g., pedometer, accelerometer, heart rate monitor), or other device by another manufacturer. The display18of the wearable electronic device10E may include a touch screen display18(e.g., LCD, LED display, OLED display, active-matrix organic light emitting diode (AMOLED) display, and so forth), as well as input structures22, which may allow users to interact with a user interface of the wearable electronic device10E.

With the foregoing in mind, a block diagram of an architecture of a micro light emitting diode (μ-LED) display18appears inFIG.7. Although the following descriptions describe μ-LEDs, the systems and methods described herein may apply to any LED, such as μ-LEDs, mini LEDs, and so forth. As shown, the display18may use a Red Green Blue (RGB) display panel60with pixels that include red, green, and blue μ-LEDs as subpixels. Support circuitry62may receive RGB-format video image data64. It should be appreciated, however, that the display18may alternatively display other formats of image data, in which case the support circuitry62may receive image data of such different image format. In the support circuitry62, a video timing controller (TCON)66may receive and use the image data64in a serial signal to determine a data clock signal (DATA_CLK) to control the provision of the image data64in the display18. The video TCON66also passes the image data64to serial-to-parallel circuitry68that may deserialize the image data64signal into several parallel image data signals70. That is, the serial-to-parallel circuitry68may collect the image data64into the particular data signals70that are passed on to specific columns among a total of M respective columns in the display panel60. As such, the data70is labeled DATA[0], DATA[1], DATA[2], DATA[3] . . . DATA[M-3], DATA[M-2], DATA[M-1], and DATA[M]. The data70respectively contain image data corresponding to pixels in the first column, second column, third column, fourth column . . . fourth-to-last column, third-to-last column, second-to-last column, and last column, respectively. The data70may be collected into more or fewer columns depending on the number of columns that make up the display panel60.

As noted above, the video TCON66may generate the data clock signal (DATA_CLK). An emission timing controller (TCON)72may generate an emission clock signal (EM_CLK). Collectively, these may be referred to as Row Scan Control signals. Circuitry on the display panel60may use the Row Scan Control signals to display the image data70. The display panel60includes column drivers (CDs)74, row drivers (RDs)76, and micro-drivers (μDs)78. Each μD78drives a number of pixels80having μ-LEDs as subpixels82. Each pixel80includes at least one red μ-LED, at least one green μ-LED, and at least one blue μ-LED to represent the image data64in RGB format.

A power supply84may provide a reference voltage (Vref)86to drive the μ-LEDs, a digital power signal88, and an analog power signal90. In some cases, the power supply84may provide more than one reference voltage (Vref)86signal. Namely, subpixels82of different colors may be driven using different reference voltages. As such, the power supply84may provide more than one reference voltage (Vref)86. Additionally or alternatively, other circuitry on the display panel60may step the reference voltage (Vref)86up or down to obtain different reference voltages to drive different colors of μ-LED.

To allow the μDs78to drive the μ-LED subpixels82of the pixels80, the column drivers (CDs)74and the row drivers (RDs)76may operate in concert. Each column driver (CD)74may drive the respective image data70signal for that column in a digital form. Meanwhile, each RD76may provide the data clock signal (DATA_CLK) and the emission clock signal (EM_CLK) at an appropriate to activate the row of μDs78driven by the RD76. A row of μDs78may be activated when the RD76that controls that row sends the data clock signal (DATA_CLK). This may cause the now-activated μDs78of that row to receive and store the digital image data70signal that is driven by the column drivers (CDs)74. The μDs78of that row then may drive the pixels80based on the stored digital image data70signal based on the emission clock signal (EM_CLK). That is, the μDs78may drive the pixels80for a duration corresponding to the pulse width generated by the emission clock signal (EM_CLK).

Often, the display18includes multiples LEDs (e.g., μ-LEDs) to efficiently illuminate different regions of the display18at respective brightness levels. In some instances, a current source of the display18may include multiple transistors (e.g., mirror transistors) that are in line with signal paths to the LEDs. To efficiently drive the LEDs (e.g., reduce or prevent power loss), circuitry of the display18may drive the LEDs with the exact amount of power from the current source to turn on the LEDs. The circuitry may drive the LEDs with the same amount of current from the current source to provide a constant current and illuminate the LEDs consistently. In some embodiments, such as when the display18includes an LCD display, a backlight system of the display18may include the multiple LEDs102. For example, the LCD display18may include a backlight of multiple LEDs to illuminate a display layer of the LCD display18to facilitate displaying an image.

However, these transistors may use some voltage, resulting in power overhead (e.g., power loss) for the LEDs. To reduce or minimize the amount of power overhead, the display18may include stacked LEDs. To illustrate inFIG.8is a schematic diagram of a stacked LED circuit100of a display panel18. As shown, the stacked LED circuit100includes a first LED102A and a second LED102B. Although the systems and methods described herein describe two LEDs102, which represents a particular embodiment, the systems and methods may include two or more LEDs102(e.g., two, four, twenty, one hundred, and so forth).

The stacked LED circuit100also includes an analog power supply104(AVDD) connected to a first resistor105. A quotient of the AVDD104and the resistor105may provide a steady current source to a first transistor106A and a second transistor106B in a cascode formation. The AVDD104, the first resistor105, the transistors106may collectively function as a current source107, as indicated by the dashed line box. The stacked LED circuit100also includes a second transistor108connected in series with the second LED102B, and connected to a negative voltage112(VNeg). The VNeg112may receive negative voltage form a power supply and may be used to turn on the LEDs102.

The transistors106may be P-channel metal-oxide-semiconductor (PMOS) transistors. An input at a gate of the first transistor106A may include an emission signal (EM) that may enable driving circuitry for LEDs102to drive the LEDs102, and an output of the first transistor106A may include a drain voltage (VDrTr). An input at a gate of the second transistor106B may include a reference voltage signal (VRef), and output from the second transistor106B may include current for the LEDs102(e.g., diode current). As previously discussed, the VRefmay refer to a reference voltage to drive the LEDs102.

The first LED102A and the second LED102B are connected in series and since they illuminate at the same time, the brightness for the pixel may be doubled. As such, the current source107may drive the LEDs102with half the amount of current to reduce the brightness back to the intended level of brightness. By reducing the driving current to half, the stacked LED circuit100may reduce power consumption. The power overhead resulting from the transistors106using some power intended for the LEDs102, may also result in a voltage drop due across a resistance (e.g., an IR drop) as a product of current (I) passing through resistance (R), such as through the first resistor105and the second resistor108. By reducing the driving current to half, the stacked LED circuit100may also reduce the IR drop across the first resistor105and the second resistor108. By way of example, the stacked LED circuit100may reduce power consumption by at least 25% in comparison to a cascode current source with a single LED102or the LEDs102not connected in series (e.g., in parallel).

In some cases, one or more LEDs102may malfunction, such that they are not operating and/or functioning as expected. For example, a malfunctioning LED102may not emit at an intended brightness level. As another example, the LED102may not turn on to emit any brightness or may continue to emit at a brightness level for longer or shorter than an intended time period. Since the stacked LED circuit102provided two LEDs102driven simultaneously by a μD78, one of the LEDs102may function as a redundant LED102. That is, if one of the LEDs102is malfunctioning, circuitry of the display18may switch to using a functioning LED102instead, such as the second LED102B, for emitting light. As will be described herein,FIGS.9-12illustrate circuits and/or methods for identifying a malfunctioning LED102and/or replacing the malfunctioning LED102(e.g., such as by driving a different, functioning LED102).

To illustrate,FIG.9is a schematic diagram of a shorting repair applied to the stacked LED circuit100ofFIG.8. As shown, the stacked LED circuit100may include the current source107which may include components (e.g., the AVDD104and the transistors106) and function as described with respect toFIG.8. The stacked LED circuit100also includes a pre-charge voltage switch120(Vpch) and a reset voltage switch122(Vrst). The circuitry of the display18may pre-charge capacitors of the LEDs102for driving the LEDs102using the Vpch120(e.g., when the switch is closed or on) prior to driving the LEDs102using the current source107. The circuitry may also reset the LEDs102using the Vrst122(e.g., when the switch is closed or on). The stacked LED circuit100also includes the VNeg112and a bias voltage126(VBias) that are coupled to a decoder130. The decoder130may select one or more LEDs102for driving. For example, the decoder130may select a first row of LEDs102that include the first LED102A and the second LED102B by connecting the LEDs102to the VNeg112while connected other components (e.g., not to be driven) to the VBias126. Although the depicted embodiment shows eight rows of the first LED102and the second LED102, the stacked LED circuit100may include one or more rows of LEDs102, in which each of the rows have two or more LEDs102connected in series (e.g., the first LED102A, the second LED102B, a third LED102C, and so forth).

To identify whether the first LEDs102A of each of the rows is working (e.g., test the LEDs102), circuitry of the display18may use the decoder130to connect the first LEDs102A to the VNeg112and the second LEDs102B of each row to VBias126. The circuitry of the display18may cause the μD78to drive respective LEDs102to emit light using the current source107. The LEDs102connected to the VNeg112may emit light while the LEDs102connected to the VBias126may not emit light. After testing the first LEDs102of each of the rows, the circuitry of the display18may identify whether the second LEDs102B of each of the rows is working. That is, the circuitry may use the decoder130to connect the second LEDs102B to the VNeg112and the first LEDs102A of each row to VBias126, and may cause the μD78to drive respective LEDs102to emit light using the current source107. During each of these tests, the LEDs102connected to the VNeg112may emit light while the LEDs102connected to the VBias126may not emit light.

However, one or more of the LEDs102that are expected to emit light and/or emit at a particular level but do not may be malfunctioning (e.g., not operating as expected). For example, the second LED102B of the second row of LEDs102is malfunctioning, as indicated by the X over the second LED102B. After determining that the LED102is malfunctioning, the second LED102B may be shorted so that only the first LED102A is used to emit the brightness for the pixel. Additionally, the circuitry may drive the first LED102A with twice the current so that the first LED102A provides the same level of brightness.

In particular, a laser device or the like may short the first LED102A and the second LED102B via a metal imprint132. The laser device may use laser to imprint the metal to short the LEDs102. In some embodiments, the metal may include moly or a similar material. The cathode of the first LED102may have electrodes exposed that may be shorted using laser, for example, to short the malfunctioning second LED102B (which is in series with the first LED102A). In general, the cathode of each of the LEDs102may have electrodes exposed so that the LEDs102may be shorted if they are determined to be malfunctioning LEDs102.

Additionally or alternatively, the stacked LED circuit100may include LEDs102that are already shorted (e.g., pre-shorted). The shorts may include metal, such as moly, indium tin oxide (ITO), or the like. To illustrate,FIG.10is a schematic diagram of a laser-cutting repair applied to the stacked LED circuit100ofFIG.8. The stacked LED circuit100may include the current source107which may include components (e.g., the AVDD104and the transistors106) and function as described with respect toFIG.8. Additionally, the circuitry of the display18may pre-charge capacitors of the LEDs102using the pre-charge voltage switch120and may reset the LEDs102using the reset voltage switch122, as described with respect toFIG.9. Furthermore, the decoder130, the VNeg112, and VBias126may operate as described with respect toFIG.9. For example, the decoder130may select one or more LEDs102for driving by connecting the LEDs to the VNeg112and connecting the unselected LEDs102to VBias126.

To determine whether the LEDs102are functioning as expected, an electroluminescence test may be performed. The test may involve a device or system of devices (e.g., a probe station) that provides ultraviolet (UV) light on the display18. The device may terminate the light and upon terminating the light, the device may capture an image of the display. The test may cause the LEDs102to glow is the LEDs102are functioning as expected. If however, the LEDs102are not glowing, the LEDs102may be determined to be malfunctioning LEDs102.

If each of the LEDs102are properly functioning, a laser device may open the shorts as opened shorts140for the functioning LEDs102using a laser. If one or more of the LEDs102are malfunctioning, the laser device may open the shorts for the functioning LEDs102while leaving the malfunctioning LEDs102shorted. That is, the laser may remove the metal for the pre-shorted LEDs102that are functioning. In the current embodiment, only the first LED102A of the third row is a malfunctioning LED102, as indicated by the X over the first LED102A. Thus, the laser device may open the short for each of the LEDs102that are functioning. In some embodiments, the laser device may open the short for each of the LEDs102in the same column and/or in the rows before the malfunctioning LED102. By way of example, for the malfunctioning first LED102A of the third row, the laser device may open the shorts for the first LEDs102A of the first and second rows.

FIG.11is a schematic diagram of a global pad shorting repair applied to the stacked LED circuit100ofFIG.8. The stacked LED circuit100may include the current source107which may function as described with respect toFIG.8. Additionally, the circuitry of the display18may pre-charge capacitors of the LEDs102using the pre-charge voltage switch120and may reset the LEDs102using the reset voltage switch122, as described with respect toFIG.9. Furthermore, the decoder130, the VNeg112, and VBias126may operate as described with respect toFIG.9. For example, the decoder130may select one or more LEDs102for driving by connecting the LEDs102to the VNeg112and connecting the unselected LEDs102to VBias126.

Generally, the stacked LED circuit100with a global pad141may be repaired similarly to the shorting repair discussed with respect toFIG.9. However, circuitry of the display18may efficiently determine whether the LEDs102are operating as expected using the global pad141. In particular, the global pad141may be shorted (e.g., connected) to each of the μDs78driving the LEDs102of the display18, such as the first LEDs102A and the second LEDs102B of each of the rows. In particular, a shorting bar142made of ITO (e.g., conducting oxide or the like material) may short the global pad141to the μDs78and the LEDs102.

In contrast to the testing for the stacked LED circuit100ofFIG.9, in which a first test is performed for the first LEDs102A (e.g., emit light from the first LEDs102A of each of the rows) and then a subsequent test is performed for the second LEDs102(e.g., emit light from the first LEDs102B of each of the rows), the stacked LED circuit100here may identify a malfunctioning LED102in one step. In particular, the global pad141is shorted to the cathode of each of the first LEDs102A and to each of the anodes of the second LEDs102B. The circuitry of the display18may drive the global pad141with a high voltage. Each of the second LEDs102B (e.g., on the right side of global pad141) should emit light if they are not malfunctioning. The circuitry of the display18may simultaneously drive the global pad141with a low voltage while at the same time enable the current source107(e.g., driving circuit) to provide the current, and each of the first LEDs102A (e.g., on the left side of the global pad141) should emit light if they are not malfunctioning. In this manner, the circuitry may efficiently identify which particular LEDs102of each of the rows are properly functioning or malfunctioning.

Here, the second LED102B of the second row is identified as a malfunctioning LED102, as indicated by the X over the LED102. The other LEDs102that remain functioning, may be selectively etched using a dynamic mask step. That is, the short at the functioning LEDs102may be removed (e.g., “un-shorting” or “opening” the circuit) by selectively etching while the selected malfunctioning second LED102B may remain shorted with the ITO material. In some embodiments, to repair the display18, the short at the malfunctioning second LED102B may also be removed, and the opened shorts of each of the LEDs102may each be replaced with a new ITO short. As such, when circuitry of the display drives the first LED102A and the second LED102B of the third row, the current may go to the first LED102A but bypass the second LED102B.

FIG.12is a schematic diagram of an electrical shunting repair applied to the stacked LED circuit100ofFIG.8. The stacked LED circuit100in the depicted embodiment may include the current source107which may function as described with respect toFIG.8. Additionally, the circuitry of the display18may pre-charge capacitors of the LEDs102using the pre-charge voltage switch120and may reset the LEDs102using the reset voltage switch122, as described with respect toFIG.9. Furthermore, the decoder130, the VNeg112, and VBias126may operate as described with respect toFIG.9. For example, the decoder130may select one or more LEDs102for driving by connecting the LEDs102to the VNeg112and connecting the unselected LEDs102to VBias126.

In the depicted embodiment, the stacked LED circuit100may also include a series of switches150. A first set of switches150A connect to the first LEDs102A of each of the rows of LEDs102while a second set of switches150B connect to the second LEDs102B of each of the rows of the LEDs102. In particular, the switches connect to the μDs78driving the respective LEDs102. When the switches150are closed (e.g., turned on) to select a particular LED102, the switches may shunt or direct current to the selected LED102. Thus, circuitry of the display18may individually test each of the LEDs102one at a time by selectively closing a switch150for driving the selected LED102.

By way of example, to drive the first LED102A of the first row, a switch connected to this LED102(as indicated by the solid line box) may be closed to complete the path to the decoder130. However, the rest of the switches150may remain open, and thus, the first LED102A of the first row may be tested individually. A second switch connecting the first LED102A of the first row to the decoder130may be closed (as indicated by the dot line box). The circuitry of the display18may turn on the current source107and the current may be directed through the completed path from the μD78to the first LED102A of the first row since the other paths are open via the open switches150, and then to the decoder130. Subsequently, the rest of the LEDs102A may be tested individually by completing the paths from the μD78to the tested LED102. In this manner, the stacked LED circuit100may provide an architecture for efficiently testing and/or repairing a malfunctioning LED102(e.g., with a redundant second LED102B). To summarize the process for testing and/or repairing,FIGS.13-16describe the processes for testing and repairing LEDs102of the stacked LED circuit100ofFIGS.9-12.

FIG.13is a process flow diagram of a method200for the shorting repair ofFIG.9. Any suitable device that may control the electronic device10and/or the circuitry of the display18, such as the processor12(e.g., one or more processors), may perform the method200. The processor12may also perform the methods described with respect to other processes described herein, such as the processes ofFIGS.14-16. The method200may be implemented by executing instructions stored in a tangible, non-transitory, computer-readable medium, such as the memory14(e.g., one or more memory devices), using the processors12. The processor12of the electronic device10may execute instructions to perform the method200that are stored in the memory14and carried out by the processor12. In some embodiments, display driving circuitry may perform method200and the methods described with respect to other processes described herein. For example, the display driving circuitry may perform the methods described inFIGS.14-16. Additionally or alternatively, the methods may be carried out using instructions (e.g., software), calibration circuitry (e.g., a computer controlling factory assets such as robotics), and so forth. Moreover, some of the methods related to a laser may be performed using a laser device in a factory setting. While the method200is described using steps in a specific sequence, it should be understood that the present disclosure contemplates that the described steps may be performed in different sequences than the sequence illustrated, and certain described steps may be skipped or not performed altogether.

At process block202, one or more first LEDs102A (e.g., primary LEDs) are connected to one or more second LEDs102B (e.g., secondary LEDs or redundant LEDs) in one or more rows of LEDs102of a display18may be determined. In particular, each of the first LEDs102A may be connected in series with a second LED102B. If any of the LEDs102in a row are malfunctioning, the malfunctioning LED102may be repaired or bypassed for emitting light for the pixel. Briefly, and as discussed in detail with respect toFIG.9, the first LEDs102A may be tested first by connected the first LEDs102A to a negative voltage while connecting the LEDs102not to be tested (e.g., LED102B) may be connected to a bias voltage. The first LEDs102A and the second LEDs102B may be tested separately to precisely determine which LED102in a row may be malfunctioning since the LEDs102are connected in series, and as such, do not provide an indication of the individual LED in the row that is malfunctioning.

At process block204, a voltage may be applied to the first LEDs102A. After the first LEDs102A are connected to the negative voltage, μDs78may drive the respective LEDs102with a voltage to turn on the LEDs102. The LEDs connected to the negative voltage, such as the first LEDs102A, should emit brightness. At decision block206, whether the first LEDs102A are operating as expected may be determined. Specifically, LEDs102that emit light at the intended brightness level and/or for the intended duration may be properly functioning. That is, if the LEDs102are functioning as expected, whether the first LEDs102are operating as expected (e.g., properly functioning LEDs102) may be determined at process block208.

If the one or more of the first LEDs102A are not operating as expected, the one or more first LEDs102A may be determined as malfunctioning at process block210. Since first LEDs102A may not be operating as expected, a laser device may short the one or more first LEDs102A that are malfunctioning (e.g., the processor12of the electronic device10causes a laser device to perform shorting). Specifically, and as previously described, the laser device may use a laser to imprint metal (e.g., moly) to short the malfunctioning first LEDs102, at process block212. In some embodiments, the malfunctioning LEDs102may be electrically shorted via switches, such as by electrically turning off the switches (e.g., open the switches for the malfunctioning LEDs102). Data indicating the LEDs102as functioning and/or malfunctioning may be stored in memory of the electronic device10.

The cathode of the malfunctioning first LED102may have electrodes exposed that may be shorted using a metal solution (e.g., moly) that can be imprinted using a laser, thereby shorting the malfunctioning LED102A. At process block214, the test and/or repair using the laser may be performed for the second LEDs102B of each of the rows.

FIG.14is a process flow diagram of a method150for laser-cutting ofFIG.10. In this embodiment, the test may be performed simultaneously for each of the LEDs102(e.g., rather than individually testing each LED102and/or a set of LEDs102). At process block252, one or more first LEDs102A being connected to one or more second LEDs102B in one or more rows of LEDs102of a display18may be determined, as discussed with respect toFIG.13. All of the LEDs102being shorted to each other and/or the μDs78may be determined. That is, the first and second LEDs102are pre-shorted. At process block254, an electroluminescence test may be performed. As previously mentioned, the test may involve providing UV light on the display18. Upon terminating the light, the electroluminescence device may capture an image of the display.

At decision block256, whether the LEDs102are operating as expected may be determined. That is, whether the LEDs102are operating as expected, such as emitting the correct level of brightness for the LEDs102(e.g., glowing LEDs), may be determined. In particular, if the LEDs102are emitting light as expected, the LEDs102may be determined as operating as expected at process block258.

However, if the one or more of the LEDs102are not emitting light as expected, the LEDs102may be determined as malfunctioning LEDs102at process block260. Since the LEDs102are not emitting light as expected and thus, malfunctioning, a laser device may open or remove shorts for the LEDs102, at process block262. That is, the laser may remove the metal for the pre-shorted LEDs102that are functioning.

FIG.15is a process flow diagram of a method300of the global pad shorting ofFIG.11. At process block302, the one or more first LEDs102A may be determined as connected to one or more second LEDs102B in one or more rows of LEDs102of a display18, as discussed with respect toFIG.12. Generally, as previously mentioned, the stacked LED circuit100may include a global pad141, in which the global pad141may function similarly to the shorting repair discussed with respect toFIG.9. Additionally, the global pad141may be determined as connected to cathodes of the first LEDs102A of the rows and to the anodes of the second LEDs102B of the rows of LEDs102. A shorting bar142made of ITO may short the global pad141to the μDs78and the LEDs102of the display18, as discussed with respect toFIG.11.

At process block304, the global pad141may be driven with a high voltage, causing each of the second LEDs102B to emit light. At the same time, the global bad140may be driven with a low voltage and each of the first LEDs102A may emit light. In this manner, identifying which LEDs102of each of the rows are properly functioning or malfunctioning, as well as identifying and the exact position of a malfunctioning LED102(e.g., a first LED102A or a second LEDB of a particular row) may be efficiently determined.

As such, at decision block306, whether the first LED102A is operating as expected may be determined. That is, are the first LEDs102emitting the correct level of brightness and/or providing the luminance for a predetermine duration upon providing current to the LEDs102. If the LEDs102are operating as expected, such as by emitting the expected level of brightness, the first LEDs102A may be determined as operating as expected at process block308. Similarly, at decision block310, whether the second LEDs102B are operating as expected may be determined. That is, the μDs78may drive the LEDs102with the current source107so that the LEDs102emit light. In some embodiments, process blocks306and310may be performed at the same or approximately the same time. If the second LEDs102B is functioning as expected (e.g., emitting the correct level of brightness and/or providing the luminance for a predetermine duration), at process block312, the second LEDs102B may be determined as operating as expected.

However, if the first LEDs102A and/or the second LEDs102B of each row of the display18are not operating as expected, such as by emitting light below the expected level of brightness, the LEDs102may be determined as malfunctioning LEDs102at process block314. As such, the processor12may determine that the display18may be determined as needing repair. To repair the malfunctioning LEDs102, at process block316, the LEDs102that are malfunctioning may be shorted. In particular, the LEDs102that are functioning may be selectively etched using a dynamic mask step. That is, the short at the functioning LEDs102may be removed (e.g., open the short) by etching while the selected malfunctioning second LED102B may remain shorted with the ITO material. In some embodiments, to repair the display18, the short at the malfunctioning second LED102B may also be removed, and the opened shorts of each of the LEDs102may each be replaced with a new ITO short. In such embodiments, when the first LED102A and the second LED102B of the third row are driven, the current from the current source107may go to the first LED102A but bypass the second LED102B.

FIG.16is a process flow diagram of a method350of electrically shunting the LEDs102ofFIG.12. At process block352, the first LEDs102A being shorted to the second LEDs102B may be determined. The LEDs102may also be connected to one or more switches150. The switches150may enable testing each of the LEDs102individually, one at a time. At process block354, the switches150for to test a particular LED102may be turned on (e.g., closed), such as to select a first LED102A of the first row. Specifically, the switches150may connect the μDs78to respective LEDs102to be driven and/or to a decoder130. As previously mentioned, the switches150are closed (e.g., turned on) to select a particular LED102while the switches150for all other LEDs102remain open (e.g., turned off). The closed path may shunt or direct current to the selected LED102and then to the decoder130. Specifically, the potential for the LED102may be known and used to drive the LED102. That is, the potentials of the respective LEDs102may be referred to for driving the selected LED102so that the LED102may be properly tested for emitting the light. Thus, the display18may individually test the LEDs102one at a time by selectively closing switches150for driving a selected LED102.

After the current goes through the selected first LED102A, at decision block356, whether the first LED102A is operating as expected may be determined. That is, whether the first LED102A is emitting light at the intended brightness level, for the intended duration, and so forth, may be determined. If it is, at process block358, the LED102may be determined as operating as expected.

In some embodiments, if the LED102is not operating as expected, a laser device may short the LED102that is malfunctioning, at process block360. Thus, the properly functioning LEDs102may remain open and ready for use for emitting the light. As previously mentioned, when the malfunctioning LED102is removed from the row (e.g., via shorting), then the functioning LED102in the row may compensate. For example, the remaining functioning LED102in the row may be driven to emit twice the level of brightness for the LED102. Subsequently, the same test for the second LED102B in the row may be performed. That is, the respective switches150to test the second LED102B of a row may be coupled for driving the second LED102B with a known potential for the particular second LED102B. Any malfunctioning second LEDs102B may be shorted. As such, using the systems and methods described herein, a stacked LED102circuit of the display18may facilitate efficiently testing and/or repairing one or more malfunctioning LEDs102while reducing power consumption.

FIG.17is a block diagram illustrating a first repair process400for repairing malfunctioning LEDs102using an ITO layer for shorting the malfunctioning LEDs102. The repair process400may involve using the global pad141, as discussed with respect toFIG.11andFIG.15, effectively removing a malfunctioning LEDs using the shorting bar, as discussed with respect toFIG.9andFIG.13, and repairing the malfunctioning LED using the ITO layer for shorting the malfunctioning LEDs. The display18may include two rows, a first row401(Row2) and a second row402(Row3), each with a first LED102A and a second LED102B that are controlled by one or more μDs78. As shown, at a first step403(Step1), a first blanket ITO layer407of ITO or similar material may be placed over the first LEDs and the second LEDs102B of each of the rows including the first row401and the second row402. By placing a blanket layer of ITO over the first LEDs and the second LED102B, each of the LEDs102may be shorted (e.g., all pixels are shorted). At a second step404(Step2), ITO patterning is performed, in which some of the ITO is removed in a patterning path so that the LEDs102may be tested. That is, the shorts are removed. In particular, a μD78may connect to the first LED102A and the second LED102B through the patterning path so that the μD78may drive the LEDs102(e.g., of a row). The patterning path includes a conductive or metal layer405. The patterning path may also pass through the first blanket ITO layer407on top of the first metal layer405, pass back through the first blanket ITO layer407and the metal layer405, and then to an anode of the second LED102B. The second LED102A is driven in series with the first LED102A. The patterning path passes back to the μD78, and as such, the shorts are opened.

At a third step406(Step3), the first LEDs102A of the entire display (e.g., of each rows including the first row402and the second row403) may be driven by the μDs78so that the display18may emit light (e.g., light-up test is performed) at the first LEDs102A. If the first LEDs102in the rows, such as the first row401and/or the second row402, do not emit light, the first LEDs A102may be identified as malfunctioning LEDs102.

In particular, the global pad141may isolate the first LEDs102A and the second LEDs102B by loads (e.g., larger or smaller loads for the first or the second LEDs102A,102B). The global pad141may also include ITO or similar materials. The global pad141may connect to each of the μDs78driving the first LED102A and the second LED102B in a respective row, and the global pad141may be set to a voltage potential for the first LED102A or the second LED102B. In the second row402, the μD78may drive the first LED102A through a path connecting the μD78to the first LED102A, through the first blanket ITO layer407, back to the global pad141, and back to the μD78before connecting to the second LED102B. In the depicted embodiment, the first LED102A of the first row401may be a malfunctioning LED102and as such, current may not pass through the path connecting the μD78to the first LED102A. Since the first LED102is a malfunctioning LED, the first LED102A may not light up when driven by the μD78.

At a fourth step408(Step4), the second LEDs102B of each of the rows may be tested. The global pad141, which isolates the first LEDs102A and the second LEDs102B by the load, may be set to a high voltage. The second LEDs102B may be driven similarly to the first LEDs102, as described with respect to the third step406. If the second LEDs102B are operating as expected, the current from the μD78smay pass through the global pad141. Here, since the first LED102A of the first row401is malfunctioning, the first LED102A is disconnected since there is no current source driving it (e.g., based on the large load). The first LEDs102A may be driven by the cathodes of the LEDs102, so when the high voltage is applied to the cathodes, the cathodes may not turn on (e.g., emit light).

The second LEDs102B may be forward bias so when the second LEDs102B are operating as expected, the second LEDs102B may pass the current back to the respective μDs78. In the depicted embodiment, the second LED102B of the second row402is malfunctioning. Thus, the first LEDs102A and the second LEDs102B of each of the rows (e.g., LEDs102of the entire display18), including the first row401and the second row402, may be determined as operating as expected or as malfunctioning LEDs102using the first step403through the fourth step408(e.g.,403,404,406, and408).

At a fifth step410(Step5), a shorting bar may be etched away. As previously mentioned, each of the LEDs102are shorted at the first step403. At this step, the shorting bar for each of the malfunctioning LEDs102may be etched away in preparation for repairing the malfunctioning LEDs102. At a sixth step412(Step6), a second blanket ITO layer409may be placed over the top layer that may include the first blanket ITO layer407, removed shorts, etc. In particular, the second blanket ITO layer409may be used for shorting the LEDs102for repair. In some embodiments, certain regions may allow the first LEDs102A and the second LEDs102B to be shorted. At a seventh step414(Step7), shorts from second blanket ITO layer409may be etched away from the LEDs102that are operating as expected while the malfunctioning LEDs102may remain shorted. As such, the μD78in the second row401that may drive the first LED102A and the second LED102B, may pass current through the deposited second blanket ITO layer409(e.g., shorting layer for repairs), then pass down through the metal layer405, and then pass through to the second LED102B. In the second row402, the first LED102A may operate as expected while the second LED102B may be a malfunctioning LED, as previously discussed. The μD78may drive the first LED102A and the LED102B. However, since the second LED102B is malfunctioning, the current may not pass through the metal layer405and instead, may pass through short from the first blanket ITO layer407to the second blanket ITO layer409, and return back to the μD78. In some embodiments, the fifth step410may be skipped and/or combined with the seventh step414.

FIG.18is a block diagram illustrating a second repair process450for sequentially identifying and repairing malfunctioning LEDs102A using a moly or an ITO layer for shorting the malfunctioning LEDs102(e.g., without using the shorting bar). At a first step452(Step1) a first blanket ITO layer407of ITO or similar material may be placed over the first LEDs and the second LEDs102B of the rows of the display18, including the first row401and the second row402. Each of LEDs (e.g., all of the pixels) may be shorted at this step. At a second step454(Step2), a first ITO patterning is performed, in which some of the ITO is removed in a patterning path so that the LEDs102may be tested. That is, the short may be removed to test the LEDs102, such as the first LEDs102A. At a third step406(Step3), the first LEDs102A of the entire display (e.g., of each rows including the first row402and the second row403) may be driven by the μDs78so that the display18may emit light (e.g., light-up test is performed) at the first LEDs102. In particular, the current from a μD78driving the first LED102A and the second LED102A of a respective row may pass current through the μD78. Since the second LED102B is still shorted (e.g., not open), the current may only pass through the first LED102A. If first LED102A is malfunctioning, the current may also not flow through the first LED102A (e.g., no current through any of the LEDs102of the row).

At a fourth step458(Step4), upon identifying a malfunctioning first LED102A, such as the first LED102A of the first row401, a laser moly layer453or similar materials (e.g., ITO and/or similar metal) may be deposited over the first LED102A. The laser moly layer453may enable testing the first LED102A and the second LED102B. As previously mentioned, if the first LED102A is malfunctioning, current may not flow through. However, the laser moly layer453may enable the current to pass through the moly and short the first LED102A, and then enables the current to flow back to μD78. Similar steps may be repeated for repairing the second LEDs102B.

In particular, at a fifth step460(Step5), a second ITO patterning step may be performed to remove ITO from the second LEDs102B so that the second LEDs102B may be tested. The ITO may be removed as discussed with respect to the second step454and/or the second step404ofFIG.17. At a sixth step462(Step6), the second LEDs102B of the entire display (e.g., of each rows including the first row402and the second row403) may be driven by the μDs78so that the display18may emit light (e.g., light-up test is performed) at the second LEDs102B. By way of example, current from the μD78driving the second LED102B of the second row402may pass through the moly, bypass the first LED102A that was repaired and pass to the second LED102B. The current may pass through the first blanket ITO layer407, the metal layer405, and back to the μD78of the pad of μD78s. Thus, light may emit from the second LED102B if it is operating as expected. However, at the second row402, no current may be received the malfunctioning second LED102B. At this point, the first LED102A of the second row402may be identified as operating as expected based on the light-up test for the first LED102A (e.g., light is emitted). The second LED102B may also be classified at this point as operating as expected or malfunctioning. That is, since the ITO or short has been removed for the second LED102B and the first and the second LEDs102are in series, the second LED102B may be classified.

Based on this test, the second LED102B of the second row402may be identified as malfunctioning, and thus, there may be no current to the second LED102B. Since the second LED102B light up when the second LEDs102were shorted in the third step456, the second LED102B ma be easily and efficiently identified as malfunctioning. Thus, the second row402may also be efficiently repaired. In particular, at a seventh step464(Step7), a second laser moly layer may be deposited at the second LED102B, as discussed with respect to step412ofFIG.17. The second LED102B may be shorted for repair, as discussed with respect toFIG.18.

It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users.

The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ,” it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).