System and method for two-dimensional backlight operation

Abstract

To provide an electronic display device having a panel that operates in conjunction with a light-emitting diode (LED) backlight.SOLUTION: A device "slopes" or gradually ramps a change in brightness of a certain LED (18) on the basis of a target brightness value of the LED, a current brightness value of the LED, and a temperature at the LED. The device also may limit power to the backlight on the basis of estimated power consumption of a current row of LEDs of the backlight (17) and power consumption of other rows of LEDs. The device also may determine a reduced voltage to be supplied to a certain LED on the basis of a current to be supplied to the LED to cause the LED to operate. The device also may send an interrupt to the backlight to block updates to the backlight while an image content is written to pixels of the panel (16).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Application No. 63 / 078,281, filed September 14, 2020, entitled "SYSTEMS AND METHODS FOR TWO-DIMENSIONAL BACKLIGHT OPERATION," which is hereby incorporated by reference in its entirety for all purposes. [Background technology]

[0002] This disclosure relates generally to electronic displays, and more particularly to backlighting for electronic displays.

[0003] This section is intended to introduce the reader to various aspects of technology that may be related to various aspects of the present disclosure, which are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0004] Some electronic displays include liquid crystal display (LCD) panels that use the light-modulating properties of liquid crystals in combination with polarizers and / or color filters to cause light passing through the panel to appear different colors and hues. Light may be provided by a backlight, e.g., made of one or more light-emitting diodes (LEDs). In some cases, the backlight may include rows and columns of light source elements (e.g., LEDs), referred to as a two-dimensional (2D) backlight. Occasionally, during operation, the brightness of certain LEDs in the backlight may suddenly increase or decrease (e.g., based on changes in image content or brightness settings). However, this sudden change in brightness over time can cause changes in the behavior of those LEDs, which can result in noticeable artifacts in the display. Additionally, the amount of power consumed by the backlight may vary depending on the image content displayed in different portions of the display. Excessive power consumption by the backlight can cause voltage drops that cause undesirable behavior in the display circuitry.

[0005] It should be noted that LEDs may operate when supplied with a current and a voltage. Specifically, the current for a given LED may be based on the desired brightness of that LED, which may depend on the image content. An LED may be enabled (e.g., emit light) by providing it with at least a threshold voltage, which may vary based on the current provided. One way to ensure that all LEDs in a backlight are enabled is to provide a relatively high voltage to all LEDs, ensuring that the voltage provided is greater than the varying threshold voltage level. However, providing such a high voltage may inefficiently consume excessive power.

[0006] Furthermore, backlights may be updated based on changes in image content. For example, a zero-dimensional (0D) backlight, which may provide a generally uniform amount of light throughout the frame, may be updated once for each new frame of image content. Therefore, a 0D backlight may operate asynchronously with respect to the LCD panel it illuminates. However, a 2D backlight may update while some pixel rows of the LCD panel are being written or settled, which may produce image artifacts such as flicker or shimmer.

[0007] Also, because 0D backlights use a single light source, they can age in a predictable manner based on operation over time. The more the backlight operates and the higher the operating temperature, the greater the aging of the backlight. In 2D backlights made with multiple light sources (e.g., LEDs), the aging can vary over time based on the content the backlight illuminates, the different temperatures each LED is exposed to (e.g., temperatures generated by adjacent components, which can be different for each LED), etc. As a result, non-uniform aging of 2D backlights can result in a "burn-in" effect and degraded display quality. Summary of the Invention

[0008] A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with an overview of certain embodiments, and that these aspects are not intended to limit the scope of the disclosure. Indeed, the disclosure may encompass a variety of aspects not set forth below.

[0009] Systems and methods are disclosed that include an electronic display having a panel (e.g., a liquid crystal display (LCD) panel) operating in conjunction with a backlight (e.g., a two-dimensional (2D) backlight). The backlight may include one or more light sources, such as light-emitting diodes (LEDs), that emit light through the panel, which causes the light to be seen as various desired colors and hues.

[0010] The present systems and methods may "ramp" or gradually increase the brightness change of an LED. Specifically, a current brightness value and a target brightness value for the LED may be received, and a ramped or intermediate brightness may be interpolated based on the current and target brightness values. In some cases, the ramped brightness may also be determined based on the temperature of the LED for increased accuracy. In this way, sudden changes in the brightness of the LED may be avoided or reduced, thus preventing or mitigating noticeable artifacts in the display.

[0011] The present system and method may also limit or reduce power to the backlight based on the target brightness of the current LED row of the backlight and the power consumption of the other LED rows of the backlight. Specifically, the power consumption (e.g., current power consumption) of the other LED rows of the backlight may be stored, and the power consumption for the current LED row to emit the target brightness may be estimated. If the sum of these power consumptions is greater than a threshold power consumption, the power supplied to all LEDs may be scaled down so as not to exceed the threshold power consumption. In this way, the power supply can be maintained appropriately, and the possibility of voltage drops can be reduced or avoided.

[0012] The present systems and methods may further determine a reduced or minimum voltage to supply to an LED based on the current supplied to the LED to operate the LED. This current may cause the LED to emit a desired brightness, for example, based on image content and / or display brightness settings. This current and reduced voltage may then be supplied to the LED to operate the LED and cause it to emit the desired brightness. The reduced voltage may be lower than a relatively high default voltage supplied uniformly to all LEDs in the backlight to ensure that all of the LEDs are operational. In this manner, power may be saved when operating the backlight.

[0013] The present systems and methods may also "stagger" backlight updates so that they are synchronized with pixel refreshes of the LCD panel, optimizing or improving image quality and reducing or minimizing display flicker. Specifically, backlight updates may be performed row by row or group of LEDs in the backlight in coordination with the LCD scanning pattern of the panel. That is, to stagger backlight updates, an interrupt may be sent to the backlight to prevent updates to one or more LED rows in the backlight (e.g., corresponding to displaying the new image frame) while image content for a new image frame is being written to the pixels of the display panel. After the image content is written to the pixels and the pixels have settled, the interrupt may be canceled. One or more LED rows in the backlight may then be updated. In this manner, the backlight may be prevented from changing while image content is being written to the display panel, reducing image artifacts on the display.

[0014] The system and method may further compensate for the aging and temperature of an LED. Specifically, a periodic compensation factor may be determined over time to compensate for the aging and temperature of the LED. These compensation factors may be combined to determine a compensation factor, and current may be supplied to the LED based on this compensation factor. In this way, display anomalies such as "burn-in" effects may be avoided or reduced, resulting in better display quality.

[0015] It should be understood that any or all of the systems and methods of this disclosure may be combined, i.e., the systems and methods of this disclosure may include an electronic display having an LCD panel operating with a 2D LED backlight that "ramps" or gradually slopes the change in brightness of certain LEDs, limits power to the backlight based on the target brightness of the current row of LEDs and the power consumption of other rows of LEDs, determines a reduced voltage to supply to certain LEDs based on the current supplied to those LEDs to operate them, staggers backlight updates to prevent updates to the backlight while image content is being written to the pixels of the LCD panel, and / or compensates for aging and temperature of certain LEDs.

[0016] Various refinements of the above-described features may exist in connection with various aspects of the present disclosure. Additional features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For example, various features discussed below in connection with one or more of the illustrated embodiments may be incorporated alone or in any combination into any of the above-described aspects of the present disclosure. The summary presented above is intended to familiarize the reader with certain aspects and contexts of embodiments of the present disclosure without limiting the claimed subject matter. [Brief explanation of the drawings]

[0017] The various aspects of the present disclosure may be better understood upon reading the following detailed description and by reference to the following drawings.

[0018] [Figure 1] 1 is a schematic block diagram of an electronic device including a transceiver, according to one embodiment of the present disclosure.

[0019] [Figure 2] 2 is a perspective view of a notebook computer representing a first embodiment of the electronic device of FIG. 1.

[0020] [Figure 3] 2 is a front view of a handheld device representing a second embodiment of the electronic device of FIG. 1.

[0021] [Figure 4] 1. FIG. 4 is a front view of another handheld device representing a third embodiment of the electronic device of FIG.

[0022] [Figure 5] FIG. 2 is a front view of a desktop computer representing a fourth embodiment of the electronic device of FIG. 1.

[0023] [Figure 6] 10A and 10B are front and side views of a wearable electronic device representing a fifth embodiment of the electronic device of FIG. 1.

[0024] [Figure 7] 2 is a schematic diagram of certain components of the electronic device of FIG. 1 according to an embodiment of the present disclosure.

[0025] [Figure 8] 2 is a block diagram of a backlight control system of the electronic device of FIG. 1 according to an embodiment of the present disclosure.

[0026] [Figure 9] FIG. 9 is a block diagram of the gradient logic of the backlight control system of FIG. 8 in accordance with an embodiment of the present disclosure.

[0027] [Figure 10] 2 is a flowchart of a method for ramping or gradually grading the change in brightness of certain light emitting diodes (LEDs) in the display of the electronic device of FIG. 1 according to an embodiment of the present disclosure.

[0028] [Figure 11] FIG. 9 is a block diagram of power limiting logic of the backlight control system of FIG. 8 according to an embodiment of the present disclosure.

[0029] [Figure 12] 2 is a flowchart of a method for limiting power consumed by a backlight of a display of the electronic device of FIG. 1 according to an embodiment of the present disclosure.

[0030] [Figure 13] FIG. 9 is a block diagram of adaptive headroom logic of the backlight control system of FIG. 8 in accordance with an embodiment of the present disclosure.

[0031] [Figure 14] 1 is a flowchart of a method for determining a reduced voltage to supply to an LED based on a current to supply to the LED to operate the LED, according to an embodiment of the present disclosure.

[0032] [Figure 15] FIG. 9 is a block diagram of backlight interrupt logic of the backlight control system of FIG. 8 in accordance with an embodiment of the present disclosure.

[0033] [Figure 16] 1 is a flowchart of a method for staggering updates to a backlight according to an embodiment of the present disclosure.

[0034] [Figure 17] FIG. 9 is a block diagram of aging compensation logic of the backlight control system of FIG. 8 according to an embodiment of the present disclosure.

[0035] [Figure 18] 2 is a schematic diagram of a temperature grating disposed across a panel of a display of the electronic device of FIG. 1 according to an embodiment of the present disclosure.

[0036] [Figure 19] 2 is a schematic diagram of an LED of the display of the electronic device of FIG. 1 surrounded by temperature spots, according to an embodiment of the present disclosure.

[0037] [Figure 20]2 is a flowchart of a method for compensating for aging and temperature of LEDs in a display of the electronic device of FIG. 1 according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0038] One or more specific embodiments of the present disclosure are described below. The described embodiments are examples of the technology disclosed herein. Moreover, in order to provide a concise description of these embodiments, not all features of an actual implementation are described herein. It should be understood that, as in any engineering or design project, in developing such an actual implementation, numerous implementation-specific decisions must be made to achieve the developer's specific goals, including compliance with system- and business-related constraints that may vary from implementation to implementation. It should also be understood that such a development effort may be complex and time-consuming, but would be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill in the art having the benefit of this disclosure.

[0039] 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 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. Furthermore, it should be understood that references to "one embodiment" or "embodiments" in the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0040] Some electronic displays include liquid crystal display (LCD) panels that use the light-modulating properties of liquid crystals in combination with polarizers and / or color filters to cause light passing through the panel to appear different colors and hues. Light may be provided by a backlight, made of, for example, one or more light-emitting diodes (LEDs). In some cases, the backlight may include rows and columns of light source elements (e.g., LEDs), referred to as a two-dimensional (2D) backlight.

[0041] During operation, the brightness or luminance of a backlit LED may occasionally increase or decrease suddenly (e.g., based on changes in image content or brightness settings). However, this sudden change in brightness over time may result in changes in the behavior of the LED, which may cause noticeable artifacts in the display. To prevent or smooth this change in brightness, the brightness of the LED may be “ramped,” or gradually sloped, between a current brightness value and a target brightness value. That is, a current brightness value and a target brightness value for the LED may be received, and a ramped, or intermediate, brightness may be interpolated based on the current brightness value and the target brightness value. In some cases, the ramped brightness may also be determined based on the temperature of the LED for increased accuracy. In this way, sudden changes in the brightness of the LED may be avoided or reduced, thus preventing or mitigating noticeable artifacts in the display.

[0042] Additionally, the amount of power consumed by the backlight may vary depending on the image content displayed in different portions of the display. If the backlight consumes too much power, it may cause voltage drops that cause the display circuitry to behave undesirably. To limit or reduce the power consumed by the backlight, the power consumption of the current LED row to emit a target brightness may be estimated, and the power consumption of the other LED rows in the backlight (e.g., current power consumption) may be stored or combined into a final or aggregate power consumption calculation. If the sum of these power consumptions is greater than a threshold power consumption, the power supplied to all LEDs may be scaled down so as not to exceed the threshold power consumption. In this way, the power supply can be maintained appropriately, and the possibility of voltage drops can be reduced or avoided.

[0043] Note that LEDs may operate when supplied with current and voltage. Specifically, the current for an LED may be based on the desired brightness of that LED, which may depend on image content. The LED may be enabled (e.g., emit light) by supplying at least a threshold voltage to the LED, which may vary based on the current supplied. One way to ensure that all LEDs in the backlight are enabled is to supply a relatively high voltage to all LEDs to ensure that the supplied voltage is greater than a varying threshold voltage level. However, supplying such a high voltage may inefficiently consume excessive power. Alternatively, a reduced or minimum voltage to be supplied to an LED may be determined based on the current supplied to that LED to operate it. This current may cause the LED to emit a desired brightness, based on, for example, image content and / or display brightness settings. Thus, this current and reduced voltage may be supplied to the LED to operate it and cause it to emit the desired brightness. The reduced voltage may be lower than the relatively high voltage uniformly supplied to all LEDs in the backlight to ensure that all LEDs are enabled. In this way, power can be saved when operating the backlight.

[0044] Furthermore, the backlight may be updated based on changes in image content. For example, a zero-dimensional (0D) backlight, which may emit a substantially uniform amount of light across an entire image frame, may be updated once for each new frame of image content. Therefore, a 0D backlight may operate asynchronously with respect to the LCD panel it illuminates. However, a 2D backlight may update while some pixel rows of the LCD panel are being written or settling, which may produce image artifacts such as flicker or shimmer. To prevent the 2D backlight from updating while some pixel rows of the LCD panel are being written or settling, updates to the backlight may be staggered to synchronize with updates to pixel values ​​of the LCD panel. Specifically, while image content for a new image frame is being written to the pixels of the LCD panel, an interrupt may be sent from the LCD panel's controller to the backlight to prevent updates to one or more LED rows of the backlight (e.g., corresponding to the display of the new image frame). After the image content is written to the pixels and the pixels have settled, the interrupt may be canceled. The backlight may then be updated. In this way, the backlight may be prevented from changing while image content is being written to the LCD panel, reducing image artifacts on the display.

[0045] Additionally, because 0D backlights use a single light source, they can age in a predictable manner based on operation over time. The more the backlight operates and the higher its operating temperature, the greater the aging degradation of the backlight. In 2D backlights made with multiple light sources (e.g., LEDs), aging can vary over time based on the content the backlight illuminates, the different temperatures each LED is exposed to (e.g., temperatures generated by adjacent components, which may be different for each LED), and so on. Therefore, non-uniform aging of 2D backlights can result in a "burn-in" effect, degrading display quality. To compensate for LED aging and temperature, a periodic compensation factor that compensates for the aging and temperature of a given LED can be determined over time. These compensation factors can be combined to determine a compensation factor, and current can be supplied to that LED based on this compensation factor. In this way, display anomalies such as the "burn-in" effect can be avoided or reduced, resulting in better display quality.

[0046] Electronic devices that implement the techniques of this disclosure are described herein. It should be further understood that any or all of the techniques of this disclosure may be combined. That is, the electronic device may include an electronic display having an LCD panel operating with a 2D LED backlight that "ramps" or gradually slopes the change in brightness of certain LEDs, limits power to the backlight based on the target brightness of the current LED row and the power consumption of other LED rows, determines a reduced voltage to supply to certain LEDs based on the current supplied to those LEDs to operate them, staggers backlight updates to prevent updates to the backlight while image content is being written to pixels of the LCD panel, and / or compensates for aging and temperature of certain LEDs.

[0047] Turning first to FIG. 1 , an electronic device 10 according to one embodiment of the present disclosure may include, among other things, one or more processor(s) 12 (e.g., processor core complexes), memory 13, non-volatile storage 14, display 15, multiple input structures 22, input / output (I / O) interfaces 24, network interfaces 26, transceivers 28, and a power supply 30. The various functional blocks illustrated in FIG. 1 may 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. Furthermore, a combination of elements may be included on a tangible, non-transitory, machine-readable medium containing machine-readable instructions. The instructions may be executed by processor core complex 12 and may cause processor core complex 12 to perform the operations described herein. It should be noted that FIG. 1 is merely one example of a particular embodiment and is intended to illustrate the types of elements that may be present in electronic device 10.

[0048] By way of example, electronic device 10 may represent a block diagram of a notebook computer as shown in FIG. 2 , a handheld device as shown in FIG. 3 , a handheld device as shown in FIG. 4 , a desktop computer as shown in FIG. 5 , a wearable electronic device as shown in FIG. 6 , or a similar device. Note that processor core complex 12 and other related items of FIG. 1 may collectively be referred to herein as “data processing circuitry.” Such data processing circuitry may be implemented, in whole or in part, as software, firmware, hardware, or any combination thereof. Furthermore, data processing circuitry may be a single housed processing module or may be incorporated, in whole or in part, within any of the other elements in electronic device 10.

[0049] In the electronic device 10 of FIG. 1 , the processor core complex 12 may be operatively coupled to the memory 13 and the nonvolatile storage 14 to execute various algorithms. Such programs or instructions executed by the processor core complex 12 may be stored on any suitable article of manufacture including one or more tangible computer-readable media, such as the memory 13 and the nonvolatile storage 14, that at least collectively store the instructions or routines. The memory 13 and the nonvolatile storage 14 may include any suitable article of manufacture for storing data and executable instructions, such as random access memory, read-only memory, rewritable flash memory, a hard drive, and an optical disk. Additionally, a program (e.g., an operating system) encoded on such a computer program product may also include instructions executable by the processor core complex 12 to enable the electronic device 10 to provide various functions.

[0050] In certain embodiments, display 15 may be a liquid crystal display (LCD), which may allow a user to easily view images generated on electronic device 10. Specifically, display 15 may include a display panel 16 (e.g., an LCD panel) including liquid crystals combined with polarizers and / or color filters to cause light passing through the panel to appear different colors and hues. In some embodiments, display 15 may include a touchscreen, which may facilitate user interaction with the user interface of electronic device 10. Furthermore, it should be understood that in some embodiments, display 15 may include one or more organic light-emitting diode (OLED) displays, or some combination of an LCD panel and an OLED panel. As shown, light passing through panel 16 may be provided by a backlight 17, made up of, for example, one or more light-emitting diodes (LEDs) 18. In some cases, backlight 17 may include rows and columns of light source elements (e.g., LEDs 18), referred to as a two-dimensional (2D) backlight.

[0051] Display 15 may include a display control system 19, or display pipe, that operates display 15. While display control system 19 is shown as part of display 15, display control system 19 may additionally or alternatively be part of processor 12 (e.g., a processor core complex). For example, display control system 19 may include pixel processing logic, control logic, one or more microcontrollers, one or more processors (e.g., 12), one or more memory devices (e.g., 13), timing generation logic, compression logic, etc. Similarly, backlight 17 may include a backlight controller 20 (e.g., having one or more processors (e.g., 12) and / or one or more memory devices (e.g., 13)) that operates backlight 17. Display control system 19 may include a backlight control system 21 that sends instructions to backlight controller 20 to ensure synchronization between updates of pixel data and updates of LED array 18 of backlight 17. In some embodiments, backlight control system 21 may include one or more processors (e.g., 12) and / or one or more memory devices (e.g., 13).

[0052] Processor 12 (e.g., as part of or in the form of a controller) may operate circuitry to input or output data generated by electronic device 10. For example, processor 12 may control and / or operate memory 13, non-volatile storage 14, display 15, input structure 22, input / output (I / O) interface 24, network interface 26, transceiver 28, power supply 30, etc. to perform operations of electronic device 10 and / or facilitate control of the operation of electronic device 10. In particular, processor 12 may generate control signals to operate transceiver 28 to transmit data over one or more communication networks.

[0053] An input structure 22 of electronic device 10 may allow a user to interact with electronic device 10 (e.g., increasing or decreasing a volume level by pressing a button). An I / O interface 24, as well as a network interface 26, may allow electronic device 10 to interface with various other electronic devices. Network interface 26 may include, for example, an interface for a personal area network (PAN) such as a Bluetooth® network, a local area network (LAN) such as an 802.11x Wi-Fi network or a wireless local area network (WLAN) such as an 802.11x Wi-Fi network, and / or a third generation (3G) wireless network. rd generation, 3G) cellular network, fourth generation (4 th generation (4G) cellular network, LTE cellular network, Long term evolution license assisted access (LTE-LAA) cellular network, 5th generation (5 th Network interface 26 may include one or more interfaces for a wide area network (WAN), such as a 5G (5th generation) cellular network or a New Radio (NR) cellular network. Network interface 26 may also include one or more interfaces for, for example, a broadband fixed wireless access network (e.g., WIMAX), a mobile broadband wireless network (Mobile WIMAX), an asynchronous digital subscriber line (ADSL, VDSL, etc.), a Digital Video Broadcasting-Terrestrial (DVB-T) network and its extension, a DVB-Handheld (DVB-H) network, an ultra-wideband (UWB) network, an alternating current (AC) power line, etc.

[0054] In certain embodiments, electronic device 10 may take the form of a computer, a portable electronic device, a wearable electronic device, or other type of electronic device. Such computers may generally be portable (e.g., laptops, notebooks, and tablet computers) and / or may be computers generally used in one location (e.g., traditional desktop computers, workstations, and / or servers). In certain embodiments, electronic device 10 in the form of a computer may be a MACBOOK®, MACBOOK® PRO, MACBOOK AIR®, iMAC®, MAC® mini, or MAC PRO® model available from Apple Inc. (Cupertino, California). By way of example, electronic device 10 is shown in FIG. 2 according to one embodiment of the present disclosure in the form of a notebook computer 10A. Notebook computer 10A may include a housing or enclosure 36, a display 15, an input structure 22, and ports associated with an I / O interface 24. In one embodiment, input structure 22 (such as a keyboard and / or touchpad) may enable interaction with notebook computer 10A, such as launching, controlling, or manipulating a graphical user interface (GUI) or applications running on notebook computer 10A. For example, the keyboard and / or touchpad may allow a user to easily interact with a user interface GUI and / or application interfaces displayed on display 15.

[0055] FIG. 3 shows a front view of handheld device 10B, representing one embodiment of electronic device 10. Handheld device 10B may represent, for example, a mobile phone, a media player, a personal data organizer, a handheld gaming platform, or any combination of such devices. By way of example, handheld device 10B may be an IPOD® or IPHONE® model available from Apple Inc. (Cupertino, California). Handheld device 10B may include an enclosure 36 that protects internal elements from physical damage and shields them from electromagnetic interference. Enclosure 36 may surround display 15. I / O interface 24 may be open through enclosure 36 and may include an I / O port for a wired connection for charging and / or content manipulation, using, for example, a Lightning connector provided by Apple Inc. (Cupertino, California), Universal Serial Bus (USB), or other similar connectors and protocols.

[0056] The user input structure 22, in combination with the display 15, may allow a user to control the handheld device 10B. For example, the input structure 22 may start or shut down the handheld device 10B, navigate the user interface to a home screen, display an application screen that the user can edit, and / or enable the voice recognition functionality of the handheld device 10B. Another of the input structures 22 may provide volume control or switch between vibrate and ring modes. The input structure 22 may also include a microphone to capture the user's voice for various voice-related functions and a speaker to enable audio playback. The input structure 22 may also include a headphone input to allow input from external speakers and / or headphones.

[0057] 4 shows a front view of another handheld device 10C, which represents another embodiment of electronic device 10. Handheld device 10C may represent, for example, a tablet computer or one of various portable computing devices. By way of example, handheld device 10C may be a tablet-sized embodiment of electronic device 10, such as an IPAD® model available from Apple Inc. (Cupertino, California).

[0058] Turning to FIG. 5, computer 10D may represent another embodiment of electronic device 10 of FIG. 1. Computer 10D may be any computer, such as a desktop computer, a server, or a notebook computer, and / or may be a standalone media player or video gaming machine. By way of example, computer 10D may be an iMAC®, MACBOOK®, or other similar device by Apple Inc. (Cupertino, California). Note that computer 10D may also be a personal computer (PC) from another manufacturer. Enclosure 36 may protect and house internal elements of computer 10D, such as display 15. In certain embodiments, a user of computer 10D may interact with computer 10D using various external input devices, such as keyboard 22A or mouse 22B (e.g., input structure 22), that may be operably coupled to computer 10D.

[0059] Similarly, FIG. 6 illustrates a wearable electronic device 10E representing another embodiment of the electronic device 10 of FIG. 1. By way of example, the wearable electronic device 10E may include a wristband 43 and may be an APPLE WATCH® by Apple Inc. (Cupertino, California). However, in other embodiments, the wearable electronic device 10E may include any wearable electronic device, such as a wearable movement monitoring device (e.g., a pedometer, an accelerometer, a heart rate monitor) or other device by another manufacturer. The electronic display 15 of the wearable electronic device 10E may include a touchscreen display 15 (e.g., an LCD, an OLED display, an active matrix organic light-emitting diode (AMOLED) display, etc.) as well as an input structure 22 that allows a user to easily interact with the user interface of the wearable electronic device 10E. In certain embodiments, as described above, each embodiment of electronic device 10 (e.g., notebook computer 10A, handheld device 10B, handheld device 10C, computer 10D, and wearable electronic device 10E) may include a transceiver 28.

[0060] 7 is a schematic diagram of certain components of display 15 of electronic device 10 of FIG. 1, in accordance with an embodiment of the present disclosure. As shown, display 15 includes a display control system 19 communicatively coupled to a timing controller 50, which is communicatively coupled to LCD panel 16. Display control system 19 may send image data to timing controller 50, which converts the image data into a format suitable for input to source drivers of panel 16 and / or generates control signals for gate drivers and source drivers of panel 16.

[0061] Display control system 19 includes a backlight control system 21 communicatively coupled to backlight controller 20, which controls the brightness of each LED 18 in backlight 17 via row drivers 52 and column drivers 54. Specifically, backlight control system 21 may instruct backlight controller 20 to set each LED 18 to a particular brightness based on the image content displayed via pixels of panel 16 (e.g., corresponding to each LED 18) and / or a brightness setting of display 15 (e.g., set by a user).

[0062] 8 is a block diagram of a backlight control system 21 of the electronic device 10 of FIG. 1 according to an embodiment of the present disclosure. As shown, the backlight control system 21 may include one or more processors 60, such as one or more processors 12 described with respect to the electronic device 10. Similarly, the backlight control system 21 may include one or more memory devices 62, such as one or more memory devices 13 described with respect to the electronic device 10.

[0063] The backlight control system 21 may also include ramp logic 64 that “ramps” or gradually slopes the change in brightness of a given LED 18. Specifically, the ramp logic 64 may receive a current brightness value and a target brightness value for that LED 18 and interpolate a ramped or intermediate brightness between the current brightness value and the target brightness value. In some cases, the ramp logic 64 may determine the ramped brightness based on the temperature at that LED 18, the temperature of a corresponding LCD pixel of the panel 16 in front of that LED 18, or both. In this way, the ramp logic 64 may avoid or reduce abrupt changes in brightness of that LED 18, thus preventing or mitigating noticeable artifacts in the display 15. The term “logic” may refer to hardware (e.g., circuitry including the processor 60), software (e.g., code or machine-executable instructions stored in the memory 62), firmware (e.g., software permanently programmed into read-only memory, including the memory 62), or any combination thereof.

[0064] The backlight control system 21 may further include power limiting logic 66 that limits or reduces the power consumed by the backlight 17. Specifically, the power limiting logic 66 may estimate the power consumption for any combination of the current row of LEDs 18 being driven at a particular time, up to the sum of the power consumptions of all rows of LEDs in the backlight 17. For example, the power limiting logic 66 may estimate the power consumption of the current row of LEDs 18 to produce a target luminance (e.g., based on image content and / or a display brightness setting) and store the power consumption (e.g., current power consumption) of the other rows of LEDs 18 in the backlight 17. If the power limiting logic 66 determines that the sum of these power consumptions is greater than a threshold power consumption, the power limiting logic 66 may scale back the power supplied to all LEDs so as not to exceed the threshold power consumption. In this way, the power limiting logic 66 may maintain an adequate power supply and reduce or avoid the possibility of voltage dropouts.

[0065] The backlight control system 21 may further include adaptive headroom logic 68 that determines a reduced or minimum voltage to be supplied to a given LED 18 based on the current supplied to that LED 18 to operate that LED 18. This current may cause that LED 18 to emit a desired brightness, based on, for example, image content and / or a display brightness setting. This current and reduced voltage may then be supplied to that LED 18 to operate that LED 18 and cause it to emit the desired brightness. The reduced voltage may be less than the relatively high voltage uniformly supplied to all LEDs 18 of the backlight 17 to ensure that all of the LEDs 18 are operable. In this manner, the adaptive headroom logic 68 may conserve power when operating the backlight 17.

[0066] Backlight control system 21 may also include backlight interrupt logic 70 that synchronously staggers updates to backlight 17 with respect to updates to pixel values ​​of LCD panel 16. Specifically, backlight control system 21 may send an interrupt to backlight 17 to prevent updates to one or more LED rows of backlight 17 (e.g., corresponding to displaying the new image frame) while image content of a new image frame is being written to the pixels of display panel 16. After the image content is written to the pixels and the pixels have settled, backlight interrupt logic 70 may cancel the interrupt. Backlight 17 may then be updated. In this manner, backlight interrupt logic 70 may prevent changes to backlight 17 while image content is being written to display panel 16, thereby reducing image artifacts on display 15.

[0067] The backlight control system 21 may further include aging compensation logic 72 that compensates for the aging and temperature of a given LED 18. Specifically, the aging compensation logic 72 may determine a periodic compensation factor over time that compensates for the aging and temperature of that LED 18. The aging compensation logic 72 may combine these compensation factors to determine a single compensation factor and provide current to that LED 18 based on this compensation factor. In this way, the aging compensation logic 72 can avoid or reduce display anomalies such as "burn-in" effects, resulting in better display quality.

[0068] It should be understood that any or all of the systems and / or methods of the present disclosure may be combined, i.e., backlight control system 21 of electronic device 10 may include any combination of ramp logic 64, power limiting logic 66, adaptive headroom logic 68, backlight interrupt logic 70, and aging compensation logic 72.

[0069] FIG. 9 is a block diagram of the ramp logic 64 of the backlight control system 21 of FIG. 8 in accordance with an embodiment of the present disclosure. The ramp logic 64 “ramps,” or gradually slopes, the change in brightness of a given LED 18 to avoid or reduce abrupt changes in brightness of that LED 18. The backlight control system 21 may include an LED brightness buffer 80 that stores brightness values ​​(e.g., in nits) of the LEDs 18 of the backlight 17. The LED brightness buffer 80 may be stored, for example, in the memory device 62. In some embodiments, the brightness values ​​of the LEDs 18 may be estimated, for example, based on the current supplied to those LEDs 18 and / or previous calibration of those LEDs 18 (e.g., as measured, tested, and / or calibrated during manufacturing). The LED brightness buffer 80 may store current brightness values ​​82 of those LEDs 18 and previous brightness values ​​(e.g., the three most recent brightness values) of those LEDs 18. In some cases, a brightness value may be determined for each LED 18, and in other cases, a brightness value may be determined for each section or "frame" of the array or grid of LEDs 18 in backlight 17. LED brightness buffer 80 may store target or desired brightness values ​​84 for those LEDs 18, which may be based on the image content displayed by display 15 (e.g., bright content or portions of content may have high brightness values ​​for the corresponding LEDs 18, and dark content or portions of content may have low brightness values ​​for the corresponding LEDs 18).

[0070] The ramp logic 64 may interpolate a ramped, or intermediate, brightness 86 for a given LED 18 between the current brightness value 82 and the target brightness value 84. The interpolation may be non-linear, allowing for any type of transition curve from the current brightness value 82 to the target brightness value 84. In some embodiments, a predetermined transition curve may be stored in the memory device 62. The ramped brightness 86 may be selected as a data point on the curve based on a time relative to the LCD pixel update time or an update index set by firmware. The update index may be based on the current or brightness provided as an update for that LED 18, allowing for easy selection of interpolation weights based on the curve between the current brightness value 82 and the target brightness value 84.

[0071] In some instances, the ramp logic 64 may determine the ramped brightness value 86 based on the temperature 88 at that LED 18 for increased accuracy. That is, because the temperature 88 at that LED 18 and / or the temperature of the corresponding LCD pixel of the panel 16 in front of that LED 18 may affect the operation of that LED 18 (e.g., change the brightness of that LED 18), the ramped brightness 86 may be generated or adjusted based on temperature. Specifically, the curve used to select the ramped brightness 86 may include a temperature axis. In some embodiments, the temperature 88 may be measured using a temperature sensor at that LED 18. In additional or alternative embodiments, the temperature 88 may be calculated using a temperature grid or table, for example, based on the current at that LED 18.

[0072] In some embodiments, the ramp logic 64 may determine an interpolated brightness between the current brightness value 82 and the target brightness value 84 based on a temperature curve, and then combine the interpolated brightness, the current brightness value 82, and the target brightness value 84 to generate the ramped brightness value 86. The ramp logic 64 may apply weights to each of the interpolated brightness, the current brightness value 82, and the target brightness value 84 to generate the ramped brightness 86. For example, the backlight control system 21 may include a gradient profile 90 that includes different weights for the interpolated brightness, the current brightness value 82, and the target brightness value 84 that vary with temperature, duration (e.g., the amount of time the LED 18 has been activated), and / or setting. That is, the weights may change depending on the temperature at the LED 18 to compensate for the temperature 88. The weights may be determined based on a calibration process (e.g., performed during manufacturing) to accurately compensate for the temperature 88 at the LED 18. If the LCD refresh rate varies, the weights may additionally or alternatively depend on the actual frame time.

[0073] Thus, the ramp logic 64 may determine a corresponding ramp profile 90 based on the temperature 88 at that LED 18 and apply the weights of that ramp profile 90 to the interpolated brightness, the current brightness value 82, and the target brightness value 84 to determine a ramped brightness value 86. The backlight control system 21 may then activate that LED 18 at the ramped brightness value 86. On the next iteration, the backlight control system 21 may store the ramped brightness value 86 in the LED brightness buffer 80 as the next current brightness value 82. In this way, the ramp logic 64 may avoid or reduce abrupt changes in the brightness of that LED 18, thus preventing or mitigating noticeable artifacts in the display 15. In some embodiments, the ramp logic 64 may generate the ramped brightness value 86 at an update rate that is higher than the update or frame rate of the LCD panel 16.

[0074] 10 is a flowchart of a method 100 for ramping, or gradually grading, the change in brightness of certain LEDs 18, in accordance with an embodiment of the present disclosure. It should be noted that while the blocks of method 100 are shown in a particular order, they may be performed in any suitable order, and at least some of the blocks may be omitted entirely. As described herein, method 100 is described as being performed by ramp logic 64 and backlight control system 21, but it should be understood that any suitable processing and / or control circuitry, such as processor 60 and / or processor core complex 12, may perform some or all of the operations of method 100 based on executing instructions stored in a memory device, such as memory device 62 and / or memory device 13.

[0075] At block 102, the ramp logic 64 receives a current brightness value 82 for that LED 18. Specifically, the current brightness value 82 may be the brightness currently being emitted by that LED 18. The current brightness value 82 may be measured (e.g., using a sensor coupled to that LED 18), estimated (e.g., based on the current supplied to that LED 18), and / or stored in and received from an LED brightness buffer 80.

[0076] At block 104, the ramp logic 64 determines or receives a target brightness value 84 for that LED 18. Specifically, the target brightness value 84 may be a desired brightness that that LED 18 should emit. The target brightness value 84 may be based on the image content backlit by that LED 18 and / or the brightness setting of that LED 18. The target brightness value 84 may be stored in or received from an LED brightness buffer 80.

[0077] At block 106, the ramp logic 64 receives the temperature 88 of that LED 18. The temperature 88 may be provided by a temperature sensor coupled to that LED 18 and / or may be estimated based on the current supplied to that LED 18. At block 108, the ramp logic 64 interpolates a ramped brightness value 86 based on the current brightness value 82, the target brightness value 84, and the temperature 88 of that LED 18. The ramp logic 64 may also, or alternatively, interpolate the ramped brightness value 86 based on the current LCD refresh rate and / or frame duration (e.g., the time an LCD frame is on the panel 16). In some embodiments, the ramp logic 64 may determine an interpolated brightness between the current brightness value 82 and the target brightness value 84 based on a predetermined temperature curve, and then combine the interpolated brightness, the current brightness value 82, and the target brightness value 84 to generate the ramped brightness value 86. The ramp logic 64 may apply weights to each of the interpolated brightness, the current brightness value 82, and the target brightness value 84 to generate the ramped brightness value 86. Specifically, the ramp logic 64 may determine a corresponding ramp profile 90 based on the temperature 88 at that LED 18 and apply weights from that ramp profile 90 to the interpolated brightness, the current brightness value 82, and the target brightness value 84 to determine the ramped brightness value 86.

[0078] Next, in block 110, backlight control system 21 may activate that LED 18 at the ramped brightness value 86. On the next iteration, backlight control system 21 may store the ramped brightness value 86 in LED brightness buffer 80 as the next current brightness value 82. In this way, method 100 may avoid or reduce abrupt changes in brightness of that LED 18, and thus prevent or mitigate noticeable artifacts in display 15.

[0079] 11 is a block diagram of the power limiting logic 66 of the backlight control system 21 of FIG. 8 in accordance with an embodiment of the present disclosure. The power limiting logic 66 limits or reduces the power consumed by the backlight 17. Specifically, the power limiting logic 66 may estimate the power consumption 120 of the current row of LEDs 18 to emit a target luminance (e.g., based on image content and / or display brightness settings). That is, the backlight control system 21 may receive or determine a target luminance that the current row of LEDs 18 should emit based on the image content to be displayed on the display 15 and / or the brightness setting of the display 15.

[0080] The backlight control system 21 may also store power consumption values ​​122 (e.g., current power consumption values) for the other rows of LEDs 18 of the backlight 17. That is, the current power consumed for each of the other rows of LEDs 18 used to display the current image content may be determined or estimated and stored in memory (e.g., memory 62). The power limiting logic 66 may sum these power consumptions and compare them to a threshold power consumption. The threshold power consumption may be any suitable power limit for the backlight 17 to consume. If the sum of the power consumptions is greater than the threshold power consumption, the power limiting logic 66 may scale down the power supplied to all of the LEDs 18 so that the power consumed by those LEDs 18 does not exceed the threshold power consumption. In some embodiments, the power limiting logic 66 may generate a power scaling factor 124 that, when applied to the power supplied by the backlight control system 21 to all of the LEDs 18, prevents the power consumed by those LEDs 18 from exceeding the threshold power consumption. In additional or alternative embodiments, the power limiting logic 66 may reduce the power supplied to all of the LEDs 18 by the same amount so that the power consumed by those LEDs 18 does not exceed the threshold power consumption. In other examples, the power limiting logic 66 may reduce (e.g., scale down) the current to a current row of LEDs 18 while not reducing the current to other rows of LEDs 18. In this manner, the power limiting logic 66 may maintain an adequate power supply and reduce or avoid the possibility of a voltage drop.

[0081] 12 is a flowchart of a method 130 for limiting the power consumed by backlight 17, according to an embodiment of the present disclosure. It should be noted that while the blocks of method 130 are shown in a particular order, they may be performed in any suitable order, and at least some of the blocks may be omitted entirely. As described herein, method 130 is described as being performed by power limiting logic 66 and backlight control system 21, but it should be understood that any suitable processing and / or control circuitry, such as processor 60 and / or processor core complex 12, may perform some or all of the operations of method 130 based on executing instructions stored in a memory device, such as memory device 62 and / or memory device 13.

[0082] In block 132, power limiting logic 66 estimates the power consumption 120 of the current LED row based on the target brightness. That is, backlight control system 21 may receive or determine a target brightness that the current LED row 18 should emit based on the image content to be displayed on display 15 and / or the brightness setting of display 15.

[0083] At block 134, the power limiting logic 66 receives stored power values ​​122 for the other rows of LEDs. The stored power consumption values ​​122 may include, for example, the power currently consumed for each of the other rows of LEDs 18 used to display the current image content. The stored power consumption values ​​122 may be measured (e.g., using sensors coupled to the rows of LEDs 18) or estimated (e.g., based on the current supplied to the LEDs 18) and stored in memory (e.g., memory 62).

[0084] At block 136, the power limiting logic 66 determines the total power consumption of the LED row. Specifically, the power limiting logic 66 may sum the estimated power consumption 120 for the current LED row and the stored power consumption 122 for the other LED rows. At block 138, the power limiting logic 66 determines whether the total power consumption is greater than a threshold power consumption. The threshold power consumption may be any suitable power limit for the backlight 17 to consume. If the total power consumption is greater than the threshold power consumption, at block 140, the power limiting logic 66 supplies power to the LED row based on a reduced power value. That is, the power limiting logic 66 and / or the backlight control system 21 may scale down the power supplied to all of the LEDs 18 so that the power consumed by those LEDs 18 does not exceed the threshold power consumption. In some embodiments, the power limiting logic 66 may generate a power scaling factor 124 that, when applied to the power supplied by the backlight control system 21 to all of the LEDs 18, prevents the power consumed by those LEDs 18 from exceeding the threshold power consumption. In additional or alternative embodiments, the power limiting logic 66 may determine an amount of power to reduce from the power supplied to all of the LEDs 18 and reduce the power supplied to all of the LEDs 18 by the same determined amount so that the power consumed by those LEDs 18 does not exceed the threshold power consumption. Thus, the current LED row may emit a brightness lower than the target brightness (because less power is being supplied than corresponds to the estimated power consumption), and other LED rows may consume less power than the stored power consumption value 122 (because less power is being supplied than corresponds to the stored power consumption value 122).

[0085] If the total power consumption does not exceed the threshold power consumption, then in block 142, backlight control system 21 supplies power to the current LED column based on the target brightness. Thus, the current LED row may consume approximately the estimated power consumption 120, and the other LED rows may consume the stored power compensation value 122, because the sum of these power compensation values ​​does not exceed the threshold power consumption. In this way, method 130 may maintain an adequate power supply and reduce or avoid the possibility of a voltage drop.

[0086] 13 is a block diagram of adaptive headroom logic 68 of backlight control system 21 of FIG. 8, in accordance with an embodiment of the present disclosure. Adaptive headroom logic 68 determines the reduced or minimum voltage ("V") supplied to certain LEDs 18. LED ") is the current ("I LED Specifically, backlight control system 21 may receive instructions 150 of a current 152 to supply to that LED 18 and communicate that current 152 to that LED 18 to cause that LED 18 to emit a desired brightness, for example, based on image content and / or a display brightness setting.

[0087] A voltage greater than the threshold voltage may be supplied to that LED 18 to enable it. The threshold voltage may vary with the supply current 152, such that the higher the supply current 152, the higher the threshold voltage, and vice versa. Thus, one way to ensure that all of the LEDs 18 in the backlight 17 are enabled is to supply all of the LEDs 18 with a relatively high voltage (e.g., a voltage greater than the highest possible threshold voltage corresponding to the highest supply current) to ensure that the supply voltage to each LED 18 is higher than the varying threshold voltage level of that LED 18. However, supplying all of the LEDs 18 with a relatively high voltage may be inefficient because each LED 18 is rarely supplied with the highest current that would raise its threshold voltage to its maximum value. Instead, the adaptive headroom logic 68 may dynamically determine a reduced voltage 154 (e.g., a minimum voltage) based on the current 152 supplied to that LED 18 to enable it. Thus, each LED 18 may be supplied with a dynamically determined different (eg, non-uniform) voltage that allows power to be saved during operation of the backlight 17.

[0088] 14 is a flowchart of a method 160 for determining a reduced voltage to supply to an LED 18 based on the current 152 to supply to that LED 18 to operate that LED 18, in accordance with an embodiment of the present disclosure. Note that while the blocks of method 160 are shown in a particular order, they may be performed in any suitable order, and at least some of the blocks may be omitted entirely. As described herein, method 160 is described as being performed by adaptive headroom logic 68 and backlight control system 21, but it should be understood that any suitable processing and / or control circuitry, such as processor 60 and / or processor core complex 12, may perform some or all of the operations of method 160 based on executing instructions stored in a memory device, such as memory device 62 and / or memory device 13.

[0089] In block 162, adaptive headroom logic 68 receives or determines a current 152 to provide to a given LED 18. Specifically, backlight control system 21 may receive an instruction 150 of a current 152 to provide to that LED 18 and communicate that current 152 to that LED 18 to cause that LED 18 to emit a desired brightness based on, for example, image content and / or a display brightness setting. Adaptive headroom logic 68 may receive or determine the current 152 based on the instruction 150.

[0090] At block 164, the adaptive headroom logic 68 determines a reduced voltage 154 to supply to that LED 18 based on the current 152. That is, the adaptive headroom logic 68 may dynamically determine the reduced voltage 154 (e.g., a minimum voltage) based on the current 152 to supply to that LED 18 to enable it to operate. In some embodiments, the reduced voltage 154 may be calibrated, measured, or determined during manufacture of the electronic device 10 (e.g., by determining the lowest voltage that operates that LED 18 with the supplied current 152). In additional or alternative embodiments, the reduced voltage 154 may be interpolated (e.g., based on calibrated data points or an interpolated curve generated using calibration data).

[0091] In block 166, backlight control system 21 supplies current 152 and reduced voltage 154 to its LEDs 18. In this manner, method 160 may conserve power when operating backlight 17.

[0092] 15 is a block diagram of backlight interrupt logic 70 of backlight control system 21 of FIG. 8 according to an embodiment of the present disclosure. Backlight interrupt logic 70 staggers updates to backlight 17 to synchronize with updates to pixel values ​​of LCD panel 16 by sending an interrupt 180 to backlight controller 20 for backlight 17 to prevent updates to one or more LED rows of backlight 17 (e.g., corresponding to displaying a new image frame) while image content for a new image frame is being written to the pixels of display panel 16. After the image content is written to the pixels and the pixels have settled, backlight interrupt logic 70 may cancel interrupt 180. Backlight controller 20 may then resume updating backlight 17. That is, rather than preventing updates to the entire backlight 17, interrupt 180 may be implemented to prevent updates to a portion of backlight 17 (e.g., one or more LEDs 18) that corresponds to the image content being written to the corresponding pixels (e.g., pixel row, pixel area) of panel 16. In this way, backlight interrupt logic 70 may prevent backlight 17 from changing while image content is being written to display panel 16, thus reducing image artifacts on display 15.

[0093] 16 is a flowchart of a method 190 for staggering updates to backlight 17, according to an embodiment of the present disclosure. It should be noted that while the blocks of method 190 are shown in a particular order, they may be performed in any suitable order, and at least some of the blocks may be omitted entirely. As described herein, method 190 is described as being performed by backlight interrupt logic 70, but it should be understood that any suitable processing and / or control circuitry, such as processor 60 and / or processor core complex 12, may perform some or all of the operations of method 190 based on executing instructions stored in a memory device, such as memory device 62 and / or memory device 13.

[0094] At block 192, backlight interrupt logic 70 receives an indication that image data is about to be written to a row of pixels of panel 16. For example, backlight control system 21 may receive image data corresponding to a frame of image data to be displayed using that row of pixels and send an indication of that image data to backlight interrupt logic 70.

[0095] In block 194, the backlight interrupt logic 70 sends an interrupt 180 to stop updates to the LEDs 18 corresponding to that pixel row. Specifically, the interrupt 180 may stop updates (e.g., new brightness control signals or commands) for those LEDs 18 that provide backlighting to the LEDs 18. In block 196, the backlight interrupt logic 70 writes image data to that pixel row. Because the brightness of those LEDs 18 is maintained, image artifacts resulting from updating those LEDs 18 while image data is being written to the pixels may be reduced.

[0096] In block 198, the backlight interrupt logic 70 determines whether the pixel row has settled. That is, the pixel voltage may change while image data is being written to the pixel or shortly thereafter, before settling. During this voltage change, the image data displayed by the pixel may also change. Eventually, the pixel voltage may settle to a relatively constant value (e.g., the voltage value remains the same or is within a threshold range of voltage values ​​for a threshold duration). The backlight interrupt logic 70 may determine that the pixel row has settled based on, for example, receiving a constant voltage value from the pixel row via one or more voltage sensors coupled to the pixel row.

[0097] If not, the backlight interrupt logic 70 may determine that the pixel row has not settled and repeat block 198. If the backlight interrupt logic 70 determines that the pixel row has settled, then in block 200, the backlight interrupt logic 70 cancels the interrupt 180. For example, the backlight interrupt logic 70 may send a cancel signal to the backlight controller 20 to unblock updates to the LEDs 18 corresponding to the pixel row. The backlight controller 20 may then resume updating those LEDs 18. In this manner, the method 190 may prevent changes to the backlight 17 while image content is being written to the display panel 16, thus reducing image artifacts on the display 15. Although the method 190 is described as being applied to a pixel row of the panel 16 and sending an interrupt to the corresponding LEDs 18, it should be understood that the method 190 may be applied to any number or configuration of pixels, such as a single pixel of the panel 16, an area or array of pixels, or all of the pixels of the panel 16.

[0098] 17 is a block diagram of the aging compensation logic 72 of the backlight control system 21 of FIG. 8 in accordance with an embodiment of the present disclosure. The aging compensation logic 72 compensates for the aging of an LED 18 and the temperature at that LED 18. Specifically, the aging compensation logic 72 may determine or receive a temperature 88 at that LED 18 over time. In some embodiments, the temperature 88 may be measured using a temperature sensor at that LED 18 or may be estimated based on the current at that LED 18. In additional or alternative embodiments, the temperature 88 may be calculated using a temperature grid or table.

[0099] 18 is a schematic diagram of a temperature grid 230 disposed on a panel 16, according to an embodiment of the present disclosure. The grid 230 may divide the panel 16 into a plurality of tiles 232. Each tile 232 may be defined by four grid points 234 and may have a temperature point 236 disposed at the center of the tile 232. The temperature points 236 may also be disposed at corners 240 of the display panel 16 and between the grid points 234 along edges 238 of the panel 16. The temperature points 236 may be locations where a temperature is sensed (e.g., via a temperature sensor) or estimated (e.g., based on a calibration performed during manufacturing of the electronic device 10 and / or components near the corresponding tile 232). As shown, the temperature points 236 may be spaced non-uniformly across the panel 16 to obtain finer resolution at various locations (e.g., locations that may experience greater temperature fluctuations or variations due to nearby components or circuitry).

[0100] Because the LED 18 may not be located at a temperature point 236, the aging compensation logic 72 may determine the temperature points 236 surrounding the LED 18 and interpolate the temperature 88 at the LED 18 based on the surrounding temperature points 236. By way of example, FIG. 19 is a schematic diagram of an LED 18 surrounded by temperature points 236, according to an embodiment of the present disclosure. The temperature 88 of the LED 18 may be interpolated based on the distance from the temperature point 236. The aging compensation logic 72 may generate a temperature compensation coefficient 212 based on the temperature of the LED 18. In some embodiments, the temperature compensation coefficient 212 may be expressed as a calibrated parameter raised to the power of a constant value, where the exponent is the difference between a reference temperature and the temperature 88 of the LED 18. It should be understood that determining the temperature of the LED 18 in this manner may be applied to any of the other logic or methods described herein, including the slope logic 64 and / or the method 100.

[0101] The aging compensation logic 72 may also determine or receive the current 210 in the LED 18 over time. The current 210 may be measured using a current sensor in the LED 18 or may be estimated based on the current supplied to the LED 18. The aging compensation logic 72 may generate a current compensation factor 214 based on the current in the LED 18. In some embodiments, the current compensation factor may be expressed as a parameterized power of the quotient of the current 210 in the LED 18 divided by a reference current. A previous compensation factor may have already been applied to the current 210 in the LED 18 by the aging compensation logic 72.

[0102] The aging compensation logic 72 may combine the temperature compensation coefficient 212 and the current compensation coefficient 214 to determine the current compensation coefficient 216. In some embodiments, the current compensation coefficient 216 may include the product of the temperature compensation coefficient 212 and the current compensation coefficient 214. For example, the aging compensation logic 72 may generate the current compensation coefficient 216 by multiplying the light emitting duty cycle of the LED 18 by the temperature compensation coefficient 212 and the current compensation coefficient 214.

[0103] The aging compensation logic 72 may then store the current compensation coefficient 216 along with other previously generated compensation coefficients 218 in a memory device, such as the memory device 62. The aging compensation logic 72 may generate a compensation coefficient 220 to be applied to the current supplied to that LED 18 based on the current compensation coefficient 216 and the previous compensation coefficient 218. For example, the compensation coefficient 220 may be an average of the current compensation coefficient 216 and the previous compensation coefficient 218. In some embodiments, the aging compensation logic 72 may apply weights to the current compensation coefficient 216 and the previous compensation coefficient 218 and generate the compensation coefficient 220 based on the weighted compensation coefficients 216, 218. For example, a greater weight may be applied to the current compensation coefficient 216 and / or newer previous compensation coefficients 218 as opposed to older previous compensation coefficients 218. In this manner, the aging compensation logic 72 can avoid or reduce display anomalies such as a “burn-in” effect, resulting in better display quality.

[0104] 20 is a flowchart of a method 250 for compensating for the aging and temperature of certain LEDs 18, according to an embodiment of the present disclosure. It should be noted that, while the blocks of method 250 are shown in a particular order, they may be performed in any suitable order, and at least some of the blocks may be omitted entirely. As described herein, method 250 is described as being performed by aging compensation logic 72 and backlight control system 21, but it should be understood that any suitable processing and / or control circuitry, such as processor 60 and / or processor core complex 12, may perform some or all of the operations of method 250 based on executing instructions stored in a memory device, such as memory device 62 and / or memory device 13.

[0105] At block 252, the aging compensation logic 72 receives or determines the temperature 88 at the LED 18. In some embodiments, the temperature 88 may be measured using a temperature sensor at the LED 18 or may be estimated based on the current at the LED 18. In additional or alternative embodiments, the temperature 88 may be calculated using a temperature grid or table. The aging compensation logic 72 may generate a temperature compensation coefficient 212 based on the temperature of the LED 18. In some embodiments, the temperature compensation coefficient 212 may be expressed as a power of a calibrated parameter, where the exponent is the quotient of the difference between a reference temperature and the temperature 88 of the LED 18 divided by a constant value.

[0106] At block 254 , the aging compensation logic 72 receives or determines the current 210 in its LED 18 . The current 210 may be measured using a current sensor in the LED 18 or may be estimated based on the current supplied to the LED 18. The aging compensation logic 72 may generate a current compensation factor 214 based on the current in the LED 18. In some embodiments, the current compensation factor may be expressed as a parameterized power of the quotient of the current 210 in the LED 18 divided by a reference current.

[0107] At block 256, the aging compensation logic 72 generates a current compensation coefficient 216 based on the temperature 88 and the current 210. Specifically, the aging compensation logic 72 may combine the temperature compensation coefficient 212 and the current compensation coefficient 214 to generate the current compensation coefficient 216. In some embodiments, the current compensation coefficient 216 may include the product of the temperature compensation coefficient 212 and the current compensation coefficient 214. For example, the aging compensation logic 72 may generate the current compensation coefficient 216 by multiplying the light emitting duty cycle of the LED 18 by the temperature compensation coefficient 212 and the current compensation coefficient 214.

[0108] At block 258, the aging compensation logic 72 stores the current compensation coefficients 216 in a memory device, such as memory device 62. At block 260, the aging compensation logic 72 receives the previously generated compensation coefficients 218 from the memory device.

[0109] At block 262, the aging compensation logic 72 generates a compensation factor 220 to be applied to the current supplied to that LED 18 based on the current compensation factor 216 and the previous compensation factor 218. For example, the aging compensation logic 72 may average the current compensation factor 216 and the previous compensation factor 218 to generate the compensation factor 220. In some embodiments, the aging compensation logic 72 may apply weights to the current compensation factor 216 and the previous compensation factor 218 and generate the compensation factor 220 based on the weighted compensation factors 216, 218.

[0110] In block 264, the backlight control system 21 provides a current to that LED 18 based on the compensation coefficient 220. Specifically, the backlight control system 21 may apply the compensation coefficient 220 to a current (e.g., by multiplying the current by the compensation coefficient 220) and provide that current to that LED 18. In this way, the method 250 can avoid or reduce display anomalies such as a "burn-in" effect, resulting in better display quality.

[0111] It should be understood that any or all of the logic and / or methods of the present disclosure may be combined. That is, electronic device 10 may include any combination of slope logic 64, power limiting logic 66, adaptive headroom logic 68, backlight interrupt logic 70, and aging compensation logic 72. Furthermore, electronic device 10 may perform any combination of methods 100, 130, 160, 190, and 250.

[0112] It should be understood that the specific embodiments described above are shown by way of example, and that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather are intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.

[0113] The techniques presented and claimed herein refer to and apply material objects and practical examples of a practical nature that demonstrably improve the art, and are thus not abstract, intangible, or purely theoretical. Furthermore, when any claim at the end of this specification contains one or more elements recited as "means for [performing] _____ [function]" or "steps for _____ [function]," it is intended that such elements be construed under 35 U.S.C. 112(f). However, for claims containing elements recited in other ways, it is intended that such elements not be construed under 35 U.S.C. 112(f).

Claims

1. 1. An electronic display device, comprising: A liquid crystal display panel; a backlight including a plurality of light emitting diodes configured to emit light through the liquid crystal display panel; one or more processors, receiving an indication of a new image frame including one or more pixel values ​​to be written to one or more pixels of the liquid crystal display panel; sending an interrupt to the backlight via a controller of the liquid crystal display panel to prevent updating of brightness of one or more light emitting diodes of the plurality of light emitting diodes, the one or more light emitting diodes corresponding to the one or more pixels of the liquid crystal display panel; canceling the interrupt via the controller of the liquid crystal display panel after the one or more pixel values ​​have been written to the one or more pixels of the liquid crystal display panel and the one or more pixels have settled; updating brightness of the one or more light emitting diodes corresponding to the one or more pixels based on the one or more pixel values ​​in response to canceling the interrupt; one or more processors configured to perform An electronic display device comprising:

2. 10. The electronic display device of claim 1, wherein the one or more processors are configured to cancel the interrupt after determining that a voltage at the one or more pixels has settled after writing the one or more pixel values. Electronic display device.

3. 3. The electronic display device of claim 2, wherein determining that the voltage on the one or more pixels has settled comprises determining that the voltage has remained constant for a threshold time duration. Electronic display device.

4. 3. The electronic display device of claim 2, wherein determining that the voltage of the one or more pixels has settled comprises determining that the voltage has remained within a threshold range for a threshold time duration. Electronic display device.

5. 3. The electronic display device of claim 2, further comprising one or more voltage sensors configured to monitor the voltage of the one or more pixels, and determining that the voltage of the one or more pixels has settled is based at least in part on measurements of the one or more voltage sensors. Electronic display device.

6. 3. The electronic display device of claim 2, wherein determining that the voltage on the one or more pixels has settled continues until the voltage on the one or more pixels has settled. Electronic display device.

7. 10. The electronic display device of claim 1, wherein updating the brightness of the one or more light emitting diodes comprises: determining a transition curve between the current luminance and the target luminance; interpolating a ramped brightness for the plurality of light emitting diodes on the transition curve based at least in part on the current brightness, the target brightness, and a temperature of the plurality of light emitting diodes; The electronic display device is configured to:

8. 10. The electronic display device of claim 1, wherein updating the brightness of the one or more light emitting diodes comprises: determining a current to supply to the one or more light emitting diodes of the plurality of light emitting diodes; determining a reduced voltage level to supply to the one or more light emitting diodes based on the current in the one or more light emitting diodes; supplying the current and the reduced voltage level to the one or more light emitting diodes, the reduced voltage level being less than a uniform voltage used for other light emitting diodes of the plurality of light emitting diodes and greater than a minimum voltage of the one or more light emitting diodes of the plurality of light emitting diodes; 1. An electronic display device comprising:

9. 1. A method comprising: receiving, at the one or more processors, an indication of a new image frame including one or more pixel values ​​to be written to one or more pixels of a liquid crystal display panel; In response to receiving the indication of the new image frame, sending an interrupt to the backlight via a controller of the liquid crystal display panel to prevent updating of brightness of one or more light emitting diode strings among a plurality of light emitting diode strings of the backlight, the one or more light emitting diode strings corresponding to the one or more pixels of the liquid crystal display panel; canceling the interrupt via the controller of the liquid crystal display panel after the one or more pixel values ​​have been written to the one or more pixels of the liquid crystal display panel and the one or more pixels have settled; updating brightness of the one or more light emitting diode strings corresponding to the one or more pixels based on the one or more pixel values ​​in response to canceling the interrupt; A method comprising:

10. 10. The method of claim 9, wherein canceling the interrupt after the one or more pixel values ​​are written to the one or more pixels of the liquid crystal display panel comprises canceling the interrupt after determining that a voltage of the one or more pixels has settled after writing the one or more pixel values. method.

11. 11. The method of claim 10, wherein determining that the voltage of the one or more pixels has settled comprises determining that the voltage has remained constant for a threshold duration. method.

12. 11. The method of claim 10, wherein determining that the voltage of the one or more pixels has settled comprises determining that the voltage has remained within a threshold range for a threshold duration. method.

13. 11. The method of claim 10, wherein determining that the voltages at the one or more pixels have settled includes receiving one or more voltage measurements from one or more voltage sensors, and determining that the voltages at the one or more pixels have settled is based at least in part on the measurements of the one or more voltage sensors. method.

14. 10. The method of claim 9, wherein updating the brightness of the one or more light emitting diodes comprises: receiving a target brightness for the plurality of light emitting diodes; determining a transition curve between a current luminance and the target luminance; A method comprising:

15. 15. The method of claim 14, further comprising: interpolating ramped brightnesses for the plurality of light emitting diodes on the transition curve based at least in part on the current brightness, the target brightness, and a temperature of the plurality of light emitting diodes; A method comprising:

16. 16. The method of claim 15, wherein updating the brightness of the one or more light emitting diodes comprises: determining a current to supply to the one or more light emitting diodes of the plurality of light emitting diodes; determining a reduced voltage level to supply to the one or more light emitting diodes based on the current in the one or more light emitting diodes; supplying the current and the reduced voltage level to the one or more light emitting diodes, the reduced voltage level being less than a uniform voltage used for other light emitting diodes of the plurality of light emitting diodes and greater than a minimum voltage of the one or more light emitting diodes of the plurality of light emitting diodes; A method comprising:

17. One or more tangible, non-transitory computer-readable media containing instructions that, when executed by one or more processors, cause the one or more processors to: receiving, at the one or more processors, an indication of a new image frame including one or more pixel values ​​to be written to one or more pixels of a liquid crystal display panel; In response to receiving the indication of the new image frame, sending an interrupt to prevent updating of brightness of one or more light emitting diodes of a plurality of light emitting diodes, the one or more light emitting diodes corresponding to the one or more pixels of the liquid crystal display panel; canceling the interrupt after the one or more pixel values ​​are written to the one or more pixels of the liquid crystal display panel; updating brightness of the one or more light emitting diodes corresponding to the one or more pixels based on the one or more pixel values ​​in response to canceling the interrupt; One or more tangible, non-transitory computer-readable media that cause the

18. 18. The one or more tangible, non-transitory computer-readable media of claim 17, wherein canceling the interrupt after the one or more pixel values ​​are written to the one or more pixels of the liquid crystal display panel comprises canceling the interrupt after determining that a voltage of the one or more pixels has settled after writing the one or more pixel values. One or more tangible, non-transitory computer-readable media.

19. 20. The one or more tangible, non-transitory computer-readable media of claim 18, wherein determining that the voltage of the one or more pixels has settled comprises determining that the voltage has remained within a threshold range for a threshold time duration. One or more tangible, non-transitory computer-readable media.

20. 20. The one or more tangible, non-transitory computer-readable media of claim 18, wherein determining that the voltages at the one or more pixels have settled comprises receiving one or more voltage measurements from one or more voltage sensors, and determining that the voltages at the one or more pixels have settled is based at least in part on the measurements of the one or more voltage sensors. One or more tangible, non-transitory computer-readable media.

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