Electronic device display with a backlight having light-emitting diodes and driver integrated circuits in the active area

Abstract

This invention provides a pixel array that can be illuminated by backlighting from a backlight source. The backlight source may include a two-dimensional array of light-emitting diodes (LEDs), with each LED placed in a corresponding cell. Different LEDs may have unique brightness levels based on the content of a given display frame. A driver integrated circuit (IC) can control one or more associated LEDs to have a desired brightness level. The driver IC may be formed in the active region of the backlight source. The driver IC may be arranged together in a daisy-chain group. Digital signals (including information such as addressing information) can be propagated through this group of driver ICs. To manage the thermal performance of the backlight source, the backlight source may include a thermally conductive layer and / or a heat sink structure. To improve the efficiency of the backlight source, the backlight source may include one or more reflective layers.

Description

[0001] This application claims priority to U.S. Patent Application No. 17 / 203,311, filed March 16, 2021; U.S. Patent Application No. 17 / 203,336, filed March 16, 2021; U.S. Patent Application No. 17 / 203,340, filed March 16, 2021; U.S. Provisional Patent Application No. 63 / 029,048, filed May 22, 2020; U.S. Provisional Patent Application No. 63 / 029,069, filed May 22, 2020; and U.S. Provisional Patent Application No. 63 / 029,082, filed May 22, 2020, the entire contents of which are incorporated herein by reference. Background Technology

[0002] The present invention relates generally to electronic devices having a display, and more specifically, to a display with backlighting.

[0003] Electronic devices (such as computers and cell phones) have displays. Some displays, such as organic light-emitting diode (OLED) displays, have an array of pixels that generate light. In this type of display, backlighting is unnecessary because the pixels themselves generate light. Other displays contain passive pixels, which can change the amount of light transmitted through the display to show information to the user. Passive pixels do not generate light themselves, so backlighting is often desired for displays with passive pixels. Passive pixels can be formed from a layer of liquid crystal material formed between two electrode layers and two polarizer layers.

[0004] In typical backlight assemblies used for displays, a side-lit light guide plate is used to distribute the backlight generated by a light source (such as a light-emitting diode). A reflector can be formed below the light guide plate to improve backlight efficiency.

[0005] Conventional backlight components can cause visible artifacts, are not robust, and can take up an unwanted amount of space within electronic devices.

[0006] Therefore, it is expected that the display will be able to provide enhanced backlighting. Summary of the Invention

[0007] The display may have a pixel array for displaying images to a viewer. This pixel array may be liquid crystal pixels formed by display layers such as a color filter layer, a liquid crystal layer, a thin film transistor layer, an upper polarizer layer, and a lower polarizer layer.

[0008] The pixel array can be illuminated by backlighting from a backlight unit. The backlight unit may include an array of light-emitting diodes (LEDs), with each LED placed within a corresponding unit. The brightness of each LED can vary in each display frame to optimize viewing on the display. Different LEDs may have unique brightness levels based on the content of a given display frame.

[0009] Driver integrated circuits (ICCs) can be used to control the light-emitting diodes (LEDs) of a backlight. Each driver IC can control one or more associated LEDs to achieve a desired brightness level. The driver IC can be formed in the active region of the backlight. For example, the LEDs can be mounted to the upper surface of a glass substrate. Alternatively, the driver IC can be mounted to the upper surface of the glass substrate. The driver IC can be distributed within the LEDs.

[0010] Driver integrated circuits can be arranged together in a daisy-chain pattern. Digital signals (which include information such as addressing information) can be propagated through the group of driver integrated circuits. Each driver integrated circuit can have a small number of input-output contacts (pins) to minimize complexity. As an example, driver integrated circuits can have four, six, or nine pins.

[0011] To manage the thermal performance of the backlight, the backlight may include a thermally conductive layer attached to the lower surface of the glass substrate of the light-emitting diode. The glass substrate may also have an exposed conductive layer coupled to a heat sink for additional heat dissipation. Sensors, such as temperature sensors and / or optical sensors, may be formed on the upper surface of the glass substrate. The sensors may provide real-time measurements to a controller, such as a timing controller. The timing controller may then control the operation of the light-emitting diodes in the backlight, at least in part, based on the sensor information.

[0012] To improve backlight efficiency, the glass substrate can be formed of white diffused glass. Additionally, a reflective layer can be formed on the upper surface of the glass substrate. A reflective layer can also be formed on the lower surface of the glass substrate. A reflective layer can be formed on the top surface of the driver integrated circuit to prevent shadows in the active area of ​​the display where the driver integrated circuit is located. The light-emitting diodes can be arranged in a non-square grid layout to reduce periodicity and prevent blurring. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of an exemplary electronic device with a display according to one embodiment.

[0014] Figure 2 This is a top view of an exemplary display according to the implementation plan.

[0015] Figure 3 It is a cross-sectional side view of an exemplary display having a backlight and a pixel array in an electronic device according to the implementation scheme.

[0016] Figure 4 It is a top view of an exemplary backlight having light-emitting diodes arranged in the corresponding units according to the implementation scheme.

[0017] Figure 5 This is a top view of an exemplary display, illustrating how different parts of the display can have different target brightness levels, according to the implementation scheme.

[0018] Figure 6 This is a cross-sectional side view of an exemplary backlight according to an embodiment, which has light-emitting diodes (LEDs) on the upper surface of a substrate and LED driver integrated circuits (ICs) on the upper surface of the substrate in a passive area of ​​the display.

[0019] Figure 7 This is a cross-sectional side view of an exemplary backlight according to an embodiment, which has light-emitting diodes (LEDs) on the upper surface of a substrate and LED driver integrated circuits (ICs) on the lower surface of the substrate in the active region of the display.

[0020] Figure 8 This is a cross-sectional side view of an exemplary backlight according to an embodiment, the exemplary backlight having light-emitting diodes (LEDs) on the upper surface of a substrate and LED driver integrated circuits (ICs) on the upper surface of the substrate in the active region of the display.

[0021] Figure 9 This is a top view of an exemplary LED array according to an embodiment, the exemplary LED array including driver ICs distributed throughout the active area of ​​the display.

[0022] Figure 10 This is a schematic diagram of an exemplary display according to an implementation scheme, which has a timing controller that directly provides signals to an LED driver IC in an active area.

[0023] Figure 11 This is a schematic diagram of an exemplary display according to an embodiment, which has a timing controller that provides a signal to a backlight controller, which then provides the signal directly to an LED driver IC in an active area.

[0024] Figure 12 This is a schematic diagram of an exemplary LED array according to an implementation scheme, the exemplary LED array having a driver IC with six pins.

[0025] Figure 13 This is a schematic diagram of an exemplary driver IC according to an implementation scheme, which has nine pins for independently controlling different LED areas.

[0026] Figure 14This is a cross-sectional side view of an exemplary LED array according to an embodiment, the exemplary LED array having both LEDs and driver ICs soldered to a glass substrate.

[0027] Figure 15 This is a top view of an exemplary backlight, according to an embodiment, showing how the conductive layer on the glass substrate can be exposed and connected to the heat sink.

[0028] Figure 16 It is based on the implementation plan. Figure 15 A cross-sectional side view of an illustrative backlight.

[0029] Figure 17 This is a top view of an exemplary backlight, illustrating how temperature and optical sensors can be distributed across the active area of ​​the backlight, according to an implementation scheme.

[0030] Figure 18 This is a cross-sectional side view of an exemplary backlight source, illustrating how the reflective layer can be attached to the lower surface of a glass LED substrate, according to an embodiment.

[0031] Figure 19 This is a cross-sectional side view of an exemplary backlight source, illustrating how the reflective layer and a separate thermally conductive layer can be attached to the lower surface of a glass LED substrate, according to an embodiment.

[0032] Figure 20 This is a cross-sectional side view of an exemplary backlight source, illustrating how a reflective thermally conductive layer can be attached to the lower surface of a glass LED substrate, according to an embodiment.

[0033] Figure 21 This is a cross-sectional side view illustrating how a substrate can be formed from white diffuse glass, according to an embodiment.

[0034] Figure 22 This is a cross-sectional side view of an exemplary backlight, illustrating how a reflective layer can be formed on the upper surface of an LED driver IC, according to an embodiment.

[0035] Figure 23 This is a top view of an exemplary LED array, showing how LEDs can be arranged in a zigzag pattern according to the implementation scheme.

[0036] Figure 24 This is a top view of an exemplary LED array, illustrating how LEDs can be arranged in a zigzag pattern with increasing zone-to-zone spacing, according to the implementation scheme.

[0037] Figure 25 It is a graph illustrating the exemplary emission distribution of the LED group in the backlight according to the implementation scheme.

[0038] Figure 26This is a top view of an exemplary LED array, illustrating how a central LED can be driven with a higher current than the surrounding peripheral LEDs to achieve the desired emission distribution, according to the implementation scheme. Detailed Implementation

[0039] Figure 1 The illustration shows exemplary electronic devices of various types that may have displays. Electronic device 10 may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular phone, a media player or other handheld or portable electronic device, a smaller device (such as a wristwatch, a hanging device, a headset or handset, a device embedded in glasses or other equipment worn on a user's head, or other wearable or micro-devices), a display, a computer monitor containing an embedded computer, a computer monitor not containing an embedded computer, a gaming device, a navigation device, an embedded system (such as a system in which electronic equipment with a display is installed in an information kiosk or a car), or other electronic equipment. Electronic device 10 may have the shape of a pair of glasses (e.g., a support frame), may be formed with a helmet-shaped shell, or may have other configurations for helping to mount and secure components of one or more displays on or near a user's head.

[0040] like Figure 1 As shown, the electronic device 10 may include control circuitry 16 for supporting the operation of the device 10. Control circuitry 16 may include storage devices such as hard disk drive storage devices, non-volatile memory (e.g., flash memory configured to form a solid-state drive or other electrically programmable read-only memory), volatile memory (e.g., static random access memory or dynamic random access memory), and so on. Processing circuitry in control circuitry 16 can be used to control the operation of device 10. This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application-specific integrated circuits, etc.

[0041] Input-output circuitry in device 10, such as input-output device 12, can be used to allow data to be supplied to device 10 and to be supplied from device 10 to external devices. Input-output device 12 may include buttons, joysticks, scroll wheels, touchpads, keypads, keyboards, microphones, speakers, audio generators, vibrators, cameras, sensors, LEDs and other status indicators, data ports, etc. Users can control the operation of device 10 by supplying commands through the input resources of input-output device 12, and can receive status information and other outputs from device 10 using the output resources of input-output device 12.

[0042] Input-output device 12 may include one or more displays, such as display 14. Display 14 may be a touchscreen display including touch sensors for acquiring touch input from a user, or display 14 may be touch-insensitive. The touch sensor of display 14 may be based on an array of capacitive touch sensor electrodes, an acoustic touch sensor structure, a resistive touch element, a force-based touch sensor structure, a light-based touch sensor, or other suitable touch sensor arrangements. The touch sensor for display 14 may be formed by electrodes formed on a common display substrate having display pixels of display 14, or may be formed by a separate touch sensor panel overlapping the pixels of display 14. If desired, display 14 may be touch-insensitive (i.e., the touch sensor may be omitted). Display 14 in electronic device 10 may be a head-up display, which can be viewed without requiring the user to move away from a typical viewpoint, or may be a head-mounted display incorporated into a device worn on the user's head. If desired, display 14 may also be a holographic display for displaying holograms.

[0043] The control circuit 16 can be used to run software, such as operating system code and applications, on the device 10. During operation of the device 10, the software running on the control circuit 16 can display images on the display 14.

[0044] Input-output device 12 may also include one or more sensors 13, such as force sensors (e.g., strain gauges, capacitive force sensors, resistive force sensors, etc.), audio sensors such as microphones, touch and / or proximity sensors such as capacitive sensors (e.g., two-dimensional capacitive touch sensors associated with a display, and / or touch sensors forming buttons, touchpads, or other input devices not associated with a display), and other sensors. According to some implementations, sensor 13 may include optical sensors such as optical sensors that emit and detect light (e.g., optical proximity sensors such as transmissive-reflective optical proximity structures), ultrasonic sensors, and / or other touch sensors and / or proximity sensors, monochrome and color ambient light sensors, image sensors, fingerprint sensors, temperature sensors, proximity sensors and other sensors for measuring three-dimensional contactless gestures (“air gestures”), pressure sensors, sensors for detecting position, orientation and / or motion (e.g., accelerometers, magnetic sensors (such as compass sensors), gyroscopes and / or inertial measurement units containing some or all of these sensors), health sensors, radio frequency sensors, depth sensors (e.g., structured light sensors and / or depth sensors based on stereo imaging devices), optical sensors (such as self-mixing sensors and light detection and ranging (LiDAR) sensors that acquire time-of-flight measurements), humidity sensors, moisture sensors, eye-tracking sensors and / or other sensors. In some arrangements, device 10 may use sensor 13 and / or other input-output devices to acquire user input (e.g., a button may be used to acquire button press input, a touch sensor overlapping the display may be used to acquire user touchscreen input, a touchpad may be used to acquire touch input, a microphone may be used to acquire audio input, an accelerometer may be used to monitor when a finger touches the input surface and thus may be used to acquire finger press input, etc.).

[0045] Display 14 may be a liquid crystal display (LCD) or a display based on other types of display technologies (e.g., an organic light-emitting diode (OLED) display). Device configurations where display 14 is a liquid crystal display are sometimes described herein as examples. However, this is merely illustrative. Any suitable type of display may be used if desired. Generally, display 14 may have a rectangular shape (i.e., display 14 may have a rectangular occupied area and a rectangular peripheral edge extending around the rectangular occupied area) or may have other suitable shapes. Display 14 may be planar or may have a curved profile.

[0046] Figure 2This is a top view showing a portion of a display 14 that may have an array of pixels 22. The pixels 22 may be color filter elements of different colors, such as a red color filter element R, a green color filter element G, and a blue color filter element B. The pixels 22 may be arranged in rows and columns and may form the active area AA of the display 14. As an example, the pixels 22 may be formed from a liquid crystal display layer. Figure 2 The rectangular shapes of the display 14 and the active area AA are merely illustrative. The active area AA may have a non-rectangular shape (e.g., a shape with one or more curved portions) if desired. For example, in one example, the active area may have rounded corners.

[0047] Figure 3 A cross-sectional side view of display 14 is shown in the figure. Figure 3 As shown, display 14 may include a pixel array such as pixel array 24. Pixel array 24 may include a pixel array such as... Figure 2 The pixel array 22 (e.g., a pixel array having rows and columns of pixels). The pixel array 24 may be formed by a liquid crystal display module (sometimes called a liquid crystal display or liquid crystal layer) or other suitable pixel array structure.

[0048] During operation of display 14, an image can be displayed on pixel array 24. Backlight unit 42 (sometimes referred to as backlight source, backlight layer, backlight structure, backlight module, backlight system, etc.) can be used to generate backlight illumination 44 through pixel array 24. This illuminates any image on pixel array 24 for viewing by a viewer such as viewer 20 viewing display 14 in direction 21.

[0049] The backlight unit 42 may include an optical film 26, a light diffuser such as a light diffuser (light diffusion layer) 34, and a light-emitting diode (LED) array 36. The LED array 36 may comprise a two-dimensional light source array, such as LEDs 38 that generate the backlight illumination 44. For example, the LEDs 38 may be arranged in rows and columns, and may be located in… Figure 3 In the XY plane.

[0050] Light generated by each light-emitting diode 38 can propagate upward in the Z direction through the light diffuser 34 and the optical film 26 before passing through the pixel array 24. The light diffuser 34 may include a light-scattering structure that diffuses the light from the light-emitting diode array 36 and thus helps to provide uniform backlight illumination 44. The optical film 26 may include films such as a dichroic filter 32, a phosphor layer 30, and a film 28. The film 28 may include a brightness enhancement film and / or other optical films (e.g., a compensation film, etc.) that help to collimate the light 44 and thus enhance the brightness of the display 14 for the user 20.

[0051] The light-emitting diode 38 can emit light of any suitable color. With an exemplary configuration, the light-emitting diode 38 emits blue light. The dichroic filter layer 32 can be configured such that blue light passes through the light-emitting diode 38 while simultaneously reflecting other colors of light. The blue light from the light-emitting diode 38 can be converted into white light by a photoluminescent material such as a phosphor layer 30 (e.g., a white phosphor material layer or other photoluminescent material that converts blue light to white light). If desired, other photoluminescent materials can be used to convert blue light into different colors of light (e.g., red, green, white, etc.). For example, a layer 30 (sometimes referred to as a photoluminescent layer or color conversion layer) may include quantum dots that convert blue light into red and green light (e.g., to produce white backlighting including red, green, and blue components). A configuration in which the light-emitting diode 38 emits white light (e.g., such that layer 30 can be omitted if desired) can also be used.

[0052] In a configuration where layer 30 emits white light, such as white light generated by phosphorescent material in layer 30, the white light emitted from layer 30 in the downward (-Z) direction can be reflected back by pixel array 24 via dichroic filter layer 32 as backlight illumination (i.e., layer 32 can help reflect the backlight source outward away from array 36). In a configuration where layer 30 includes, for example, red and green quantum dots, dichroic filter 32 can be configured to reflect red and green light from the red and green quantum dots respectively to help reflect the backlight source outward away from array 36. By placing the photoluminescent material of backlight source 42 (e.g., the material of layer 30) above diffusion layer 34, light-emitting diodes 38 can be configured to emit more light toward the edges of the light-emitting diode cells (sheets) of array 36 than at the center of these cells, thereby helping to enhance the uniformity of backlight illumination.

[0053] In a configuration using a liquid crystal display to form the pixel array 24, the pixel array 24 may include liquid crystal layers such as liquid crystal layer 52. Liquid crystal layer 52 may be sandwiched between display layers such as display layers 58 and 56. Layers 56 and 58 may be interposed between a lower polarizer layer 60 and an upper polarizer layer 54. Other types of liquid crystal display structures may be used to form the pixel array 24 if desired.

[0054] Layers 56 and 58 may be formed from transparent substrate layers such as light-transmitting glass or plastic layers. Layers 56 and 58 may be layers such as thin-film transistor layers and / or color filter layers. Conductive traces, color filter elements, transistors, and other circuits and structures may be formed on the substrates of layers 58 and 56 (e.g., to form thin-film transistor layers and / or color filter layers). Touch sensor electrodes may also be incorporated into layers such as layers 58 and 56, and / or touch sensor electrodes may be formed on other substrates.

[0055] In an exemplary configuration, layer 58 may be a thin-film transistor layer comprising an array of pixel circuits based on thin-film transistors and associated electrodes (pixel electrodes) for applying an electric field to liquid crystal layer 52 and thereby displaying an image on display 14. Layer 56 may be a color filter layer comprising an array of color filter elements for providing display 14 with the ability to display color images. Layer 58 may be a color filter layer, and layer 56 may be a thin-film transistor layer, if desired. Configurations in which color filter elements are combined with thin-film transistor structures on a common substrate layer may also be used.

[0056] During operation of the display 14 in device 10, control circuitry (e.g., one or more integrated circuits on a printed circuit) can be used to generate information (e.g., display data) to be displayed on the display 14. The information to be displayed can be transmitted via signal paths to display driver integrated circuits such as circuit 62A or circuit 62B, such as signal paths formed by conductive metal traces in rigid or flexible printed circuits such as printed circuit 64 (as an example). Integrated circuits such as integrated circuit 62A and / or flexible printed circuits such as flexible printed circuit 64 may be attached to substrate 58 in flange region 66 (as an example).

[0057] Figure 4 This is a top view of an exemplary array of light-emitting diodes for the backlight 42. Figure 4 As shown, the LED array 36 may include rows and columns of LEDs 38. Each LED 38 may be associated with a corresponding cell (tile area) 38C. The length D of the edge of the cell 38C may be 2 mm, 18 mm, 1 mm-10 mm, 1 mm-4 mm, 10 mm-30 mm, greater than 5 mm, greater than 10 mm, greater than 15 mm, greater than 20 mm, less than 25 mm, less than 20 mm, less than 15 mm, less than 10 mm, or other suitable dimensions. If desired, hexagonal tile arrays and arrays of LEDs 38 organized in other suitable array patterns may be used. In an array with rectangular cells, each cell may have sides of equal length (e.g., each cell may have a square outline in which four cell edges of equal length surround the corresponding LED) or each cell may have sides of different lengths (e.g., a non-square rectangular shape). The LED array 36 may have rows and columns of square LED regions such as cells 38C (e.g., a two-dimensional array of cells 38C). Figure 4 The configuration is merely illustrative.

[0058] In some cases, each unit 38C may include a single light-emitting diode (LED). Alternatively, each unit 38C may have a light source formed by an array of LED dies (e.g., a plurality of individual LEDs 38 arranged in an array, such as a 2×2 group or a 3×3 group of LEDs in each unit 38C). The diodes 38 in the light source 38' may be mounted on a common substrate, on a printed circuit board substrate extending across the array 36, on a glass substrate extending across the array 36, or in other desired arrangements within the array 36. Generally, each unit 38C may include: a single LED, a pair of LEDs, 2 to 20 LEDs, at least 2 LEDs, at least 4 LEDs, at least 8 LEDs, less than 5 LEDs, between 4 and 12 LEDs, between 8 and 12 LEDs, between 8 and 10 LEDs, 9 LEDs, or other desired number of LEDs.

[0059] The light-emitting diode 38 can be controlled uniformly by the control circuitry in device 10 or can be controlled individually. Individual control of the light-emitting diode allows the electronic device to implement a local dimming scheme, which helps improve the dynamic range of the image displayed on pixel array 24 and potentially reduces the power consumption of the backlight. The dynamic range of a display can be considered as the ratio between the highest intensity of light (e.g., the brightest light) that the display can emit and the lowest intensity of light (e.g., the darkest light) that the display can emit.

[0060] If all the light-emitting diodes in the backlight unit 42 are uniformly controlled, the dynamic range of the display can be limited. Consider... Figure 5 The example depicted in [the text]. Figure 5 In this example, objects such as objects 72-1 and 72-2 are displayed on monitor 14 (sometimes referred to as screen 14). Object 72-1 may have a high brightness level. Object 72-2 may have a medium brightness level. The background of the monitor may have a low brightness level. If... Figure 5If the backlight LEDs of display 14 are uniformly controlled, then all LEDs can be set to a brightness optimized for object 72-1. In this scenario, object 72-1 can be displayed at its expected brightness. However, the background of the display also receives a backlight with a high brightness optimized for object 72-1. Therefore, due to display limitations such as light leakage through pixels or other limitations, the background of the display may appear brighter than expected, and the dynamic range of the display may be lower than expected. Alternatively, all LEDs can be set to a brightness optimized for the background of the display. In this scenario, the background can be displayed at its expected brightness. However, object 72-1 also receives a backlight with a low brightness optimized for the background. Therefore, object 72-1 will appear darker than expected, and the dynamic range of the display will be lower than expected. In another embodiment, the brightness of all LEDs can be set to a brightness optimized for object 72-2. In this scenario, object 72-1 will appear darker than expected, and the background will appear brighter than expected.

[0061] Furthermore, unified control of all LEDs in the backlight unit 42 can introduce power consumption limits. The maximum permissible power consumption of the backlight unit prevents all LEDs from operating at peak brightness levels. For example, all LEDs may not be able to emit light with the desired brightness for the object 72-1 while meeting power consumption requirements.

[0062] In summary, uniformly operating all LEDs in the backlight results in consistent backlight brightness across the entire display, forcing a trade-off in the aesthetics of the displayed image. Parts of the display may be darker or brighter than expected, and the display's dynamic range will be lower than desired.

[0063] To increase the dynamic range of the display (and allow peak brightness levels without exceeding power consumption requirements), the light-emitting diodes (LEDs) in the backlight unit 42 can be individually controlled. For example, the LEDs in area 14-1 of the display can have high brightness optimized for the high brightness of object 72-1, the LEDs in area 14-2 of the display can have brightness optimized for the intermediate brightness of object 72-2, and the LEDs in area 14-3 of the display can have low brightness optimized for the low brightness of the display background. In one example, the LEDs in area 14-1 can operate at maximum brightness, while the LEDs in the background area 14-3 can be turned off (e.g., operate at minimum brightness). Changing the brightness of the LEDs across the entire display in this way increases the dynamic range of the display.

[0064] Therefore, a two-dimensional array having an independent, controllable light source, such as a light-emitting diode (LED) 38, for generating backlight illumination 44 can increase the dynamic range of the display. A backlight source with a two-dimensional array of LEDs is sometimes referred to as a two-dimensional backlight source. These types of backlight sources are sometimes also referred to as direct-illumination backlight sources. Direct-illumination backlight sources emit light perpendicularly toward the pixel array, which is the opposite of backlight sources with side-lit light guides (where light is emitted parallel to the plane of the pixel array and redirected perpendicularly toward the pixel array through the light guide).

[0065] Driving circuitry may be included in the display 14 to control the light-emitting diodes (LEDs) in the backlight 42. The LED driving circuitry may be formed from integrated circuits, thin-film transistor circuits, and / or other suitable circuitry. In one example, the driving circuitry may be integrated as a thin-film transistor circuit onto a rigid printed circuit board (e.g., a printed circuit board having multiple layers of dielectric material and conductive layers, such as polyimide). However, the associated cost of this arrangement may be high, especially in backlights with a large number of LEDs. An alternative arrangement of the LED driving circuitry uses a driver integrated circuit (sometimes referred to as a driver IC) to be included in the backlight 42. Each driver IC can control one or more corresponding LEDs. This allows the LEDs to be controlled to have varying brightness levels on the backlight. In one example, the driver integrated circuit may also be used in conjunction with a glass substrate. In other words, instead of mounting the LEDs and driver ICs on a rigid printed circuit board (e.g., formed using polyimide), the LEDs and driver ICs can be mounted on a glass substrate. The glass substrate may have conductive traces (e.g., copper traces) to allow signals to be transmitted between components when necessary.

[0066] There are several options for mounting LEDs and their corresponding driver ICs on the substrate. For example... Figure 6 As shown, LED38 is mounted on the upper surface of substrate 84. Figure 6 In this arrangement, the driver IC 82 is also mounted on the upper surface of the substrate 84 in the passive region IA. The area with the backlight 38 corresponds to the active region AA of the display (e.g., the light-emitting region of the display). The backlight 42 can be described as having active and passive regions, similar to a pixel array. The active region of the backlight and the active region of the pixel array may have the same area. The passive region of the backlight and the passive region of the pixel array may have the same area, or optionally have different areas. The active and passive regions of the backlight or pixel array may sometimes be simply referred to as the active and passive regions of the display.

[0067] like Figure 6As shown, driver IC 82 is positioned at the periphery of the substrate in the passive region (IA) of the display. Driver ICs could all be positioned at the periphery of substrate 84, each controlling its corresponding group of light-emitting diodes. However, this type of arrangement has several limitations. First, it is generally desirable to minimize the size of the passive region. The passive region occupies valuable space within the electronic device without contributing to the aesthetics of the display. Having driver ICs at the periphery of the display undesirably increases the display's footprint without increasing the light-emitting area. Furthermore, positioning driver ICs only in the passive region of the display makes increasing the number of LEDs within the backlight challenging. By having driver ICs only at the periphery of the backlight, each driver IC may have to control a large number of light-emitting diodes (because the peripheral driver ICs must control both the center LED and the peripheral LEDs).

[0068] Figure 7 An alternative configuration of the backlight is shown. As shown, in this arrangement, the light-emitting diode 38 is positioned on the upper surface of the substrate 84, while the driver IC 82 is positioned on the lower surface of the substrate 84. Positioning the driver IC on the lower surface in this manner eliminates the interference with the backlight. Figure 6 The need for a large passive area. In other words, the active area can actually extend to the edge of the substrate 84. However, positioning the driver IC on the lower surface of the substrate increases the total thickness 86 of the backlight unit. In addition, the driver IC 82 may require more complex conductive wiring (e.g., with conductive vias) to properly control the light-emitting diodes on the opposite sides of the substrate 84.

[0069] Figure 8 This is a cross-sectional side view of another possible arrangement, where the driver IC is positioned on the upper surface of the substrate 84 within the active region. As shown, the driver IC can be positioned between the LEDs of the backlight. This arrangement minimizes the size of the passive region (because the driver IC does not increase the size of the passive region). Because the driver IC is on the upper surface of the substrate 84, the thickness and complexity of the backlight can be reduced. Furthermore, because the driver IC is positioned within the active region, each LED can have a corresponding driver IC. Therefore, the driver IC can have low complexity and size (because each driver IC only needs to control a small number of LEDs). Using low-complexity driver ICs reduces the number of interconnects required and allows the backlight size to be scaled up to a larger size (i.e., a larger number of LEDs within the backlight).

[0070] Digital signals can be used to control the driver IC 82 (sometimes called LED driver IC 82 or backlight driver IC 82). Using digital control lines for the backlight allows for greater backlighting on a single substrate, reduces the total pin count per driver IC, reduces the number of interconnects within the backlight, and increases the magnitude of the drive current achieved by the driver IC.

[0071] As discussed above, substrate 84 may optionally be a rigid printed circuit board (e.g., having multiple insulating layers formed of a dielectric material such as polyimide). Alternatively, to reduce the manufacturing cost and complexity of the LED array, substrate 84 (sometimes referred to as LED substrate 84) may be formed of glass. Conductive traces (e.g., copper traces) may be deposited on the glass substrate to allow electrical connections between components mounted to the glass substrate.

[0072] Figure 9 This is a top view of an exemplary light-emitting diode array, which has driver ICs distributed throughout the active area of ​​the display. For example... Figure 9 As shown, each driver IC 82 controls a corresponding LED group 102. Each LED group 102 (sometimes referred to as LED area 102) may include one or more light-emitting diodes (LEDs). The LEDs may be connected in series between the power supply line 106 and the driver IC. Figure 9 In the example, each LED zone 102 includes nine LEDs connected in series between the power line 106 and the driver IC.

[0073] In this document, the term LED group (or LED area) can be used to refer to an independently controllable group of LEDs. For example, a first and a second LED controlled separately would be referred to as a first unique LED group and a second unique LED group (even if each group contains only one LED). In contrast, nine LEDs controlled together are referred to as a single LED group. Each LED group has associated LED units, which can refer to the light-emitting area associated with that LED group. Because LEDs emit light over a wide angular range (as opposed to highly collimated light), the area occupied by the light-emitting area associated with a given LED group will be larger than the area occupied by the LED group itself. Because each LED group is controlled to have a single brightness value, the LED units associated with each group can have an associated single brightness value. In other words, ideally, the brightness can be uniform across the LED units. In practice, some non-uniformity may exist across the LED units (e.g., caused by hot spots on the LEDs). Figure 3 The membrane 26 under discussion can be designed to increase the uniformity of light within each LED unit.

[0074] Power line 106 can provide a power supply voltage VLED (e.g., a positive power supply voltage) across the LED array. Each LED group can have a light-emitting diode with a first terminal (e.g., anode) coupled to the power line. The second terminal (e.g., cathode) of the LED is then connected to the first terminal of the next LED. This chain can continue, wherein each LED has a first terminal coupled to the second terminal of the preceding LED and a second terminal coupled to the first terminal of the following LED. Figure 9 In the example, each LED has an anode coupled to the cathode of the preceding LED and a cathode coupled to the anode of the following LED. The first LED in the group has an anode coupled to power line 106. The last LED in the group has a cathode coupled to driver IC 82.

[0075] If needed, the arrangement can be reversed, wherein the first LED in the group has a cathode coupled to a power line (e.g., a ground power line), the last LED in the group has an anode coupled to a driver IC, and the other LEDs have cathodes coupled to the anode of the preceding LED and anodes coupled to the cathode of the following LED.

[0076] like Figure 9 As shown, driver ICs can optionally be arranged in an array of rows and columns. Each row and column of driver ICs can include any desired number of driver ICs. Each driver IC 82 has input-output contacts referred to as pins. Driver ICs use pins to transmit and receive signals.

[0077] exist Figure 9 In this configuration, each driver IC has four pins (P1, P2, P3, and P4). The various subgroups of the driver IC can be connected in series (e.g., daisy chain). Figure 9 In this configuration, each column of driver ICs is linked together. However, it should be noted that smaller groups of larger driver ICs can be linked together if needed.

[0078] Pin P4 is sometimes referred to as the input pin, and pin P1 is sometimes referred to as the output pin. Used for one of the driver ICs in a given column (e.g., Figure 9 The input from the control line 108-1 can be received at pin P4 of driver IC 82-1. The input from pin P4 of driver IC 82-1 can then be output at pin P1 of driver IC 82-1. The output from driver IC 82-1 can then be received at pin P4 of driver IC 82-2 (e.g., the next driver IC in the column).

[0079] In other words, the output of each driver IC is provided as an input to the chain (e.g., in...). Figure 9The next driver IC in the column. This means that the output pin P1 of each driver IC is electrically connected to the input pin P4 of the adjacent driver IC. Therefore, information provided via signal line 108-1 can be propagated through the driver ICs in a given column. In one example, signal line 108-1 is a digital signal line configured to provide initialization information (e.g., address information) to the driver IC. The initialization information is provided to driver IC 82-1 via signal line 108-1. Driver IC 82-1 then passes the initialization information to the next driver IC (82-2), which in turn passes the initialization information to the next driver IC, and so on.

[0080] Each driver IC may have a corresponding digital signal line for providing initialization information to the input pin P4 of at least one driver IC. For example... Figure 9 As shown, the second-row driver IC may have a corresponding digital signal line 108-2 that provides information to pin P4 of driver IC 82-3. Driver IC 82-3 then passes initialization information to the next driver IC (82-4), which in turn passes initialization information to the next driver IC, and so on.

[0081] Each driver IC also includes a pin P3 coupled to a corresponding signal line. For example, pin P3 of driver ICs 82-1 and 82-2 is coupled to signal line 104-1. Pin P3 of driver ICs 82-3 and 82-4 is coupled to signal line 104-2. In other words, each row of driver ICs may have a corresponding signal line for providing information to pin P3 of the driver IC. In this example, signal line 104-1 can be used to provide LED brightness values ​​to the driver IC. For example, signal line 104-1 instructs driver IC 82-1 to update the brightness of its corresponding LED group 102 to a first given size, instructs driver IC 82-2 to update the brightness of its corresponding LED group 102 to a second given size, and so on. Signal line 104-2 instructs driver IC 82-3 to update the brightness of its corresponding LED group 102 to a third given size, instructs driver IC 82-4 to update the brightness of its corresponding LED group 102 to a fourth given value, and so on.

[0082] Signal lines 104 and 108 can be digital signal lines used to transmit digital signals. Signal lines can be used to transmit data, instructions, or any other desired information. Therefore, signal lines are sometimes referred to as control lines, data lines, etc. Multiple signal lines can be part of a single bus 110. Figure 9 An example is shown in which signal lines 104-1, 104-2, 108-1, and 108-2 are part of bus 110.

[0083] An LED array may include multiple buses, each bus providing a signal to a corresponding subgroup of driver IC columns. In other words, an LED array may have a given number of buses (x). Each of these buses may provide one or more signals to a given number of driver IC columns (y). Each driver IC column may have a given number of driver ICs (z). Any desired values ​​can be used for x, y, and z. In an illustrative example, there may be 24 buses, each with 2 driver IC columns, and 27 driver ICs per column. This example is merely illustrative. In general, an LED array may include any desired number of buses (e.g., 1, 2, more than 2, more than 5, more than 10, more than 20, more than 30, more than 50, more than 100, more than 500, less than 100, less than 40, less than 30, less than 20, between 20 and 30, between 20 and 25, between 15 and 50, etc.). The LED array may include any desired number of driver IC columns per bus (e.g., 1, 2, 3, 4, more than 4, more than 8, less than 10, less than 5, between 1 and 4, etc.). The LED array may also include any desired number of driver ICs per driver IC column (e.g., more than 5, more than 10, more than 20, more than 30, more than 50, more than 100, more than 500, less than 100, less than 40, less than 30, less than 20, between 20 and 30, between 25 and 30, between 20 and 50, etc.). The bus may also provide signals to a portion of the columns of driver ICs in the arrangement, where only a portion of one or more columns are linked together.

[0084] Pin P2 in each driver IC can be coupled to ground (e.g., ground power supply voltage). Therefore, Figure 9 Each driver IC in the circuit draws current to ground through its LED group 102. Figure 9 In the example, each driver IC is coupled between the cathode of the last LED in the chain and ground. This example is merely illustrative. In an alternative arrangement, each driver IC may be coupled between the anode of the first LED in the chain and the positive power supply line 106.

[0085] Figure 9 The signal lines (e.g., 104-1, 104-2, 108-1, 108-2, and 106) in the LED array can be coupled to connection area 104 of the LED array. Connection area 105 can be, for example, a connector coupled to a controller detached from the LED substrate. This example is merely illustrative. In general, any desired connection scheme can be used to provide the desired signal on the signal lines.

[0086] Each driver IC may have a length of 212 and a width of 214. Reducing the complexity of the driver IC (e.g., by having only four pins, allowing each driver IC to control only one group of LEDs, etc.) allows for a reduction in the length and width of the driver IC. The length and width of the driver IC can be any desired corresponding distance (e.g., less than 0.5 mm, less than 1.0 mm, less than 0.4 mm, less than 0.3 mm, less than 0.2 mm, greater than 0.1 mm, greater than 0.2 mm, greater than 0.3 mm, between 0.2 mm and 0.5 mm, between 0.30 mm and 0.35 mm, etc.). In an exemplary example, both the length 212 and the width 214 may be less than 0.5 mm. Both the length 212 and the width 214 may be between 0.30 mm and 0.35 mm.

[0087] During the operation of LED array 36, the driver ICs may operate during an addressing phase (sometimes called the initialization phase). During the addressing phase, signal line 108 assigns an address (e.g., from an external controller) to the driver IC. The address can be propagated through driver ICs within a given column. In other words, during the addressing phase, each driver IC (except the last driver IC in the chain) provides an output on pin P1 that is received by pin P4 of the adjacent driver IC (e.g., via a digital signal line coupled between the pins). In some embodiments, the same information packets can be passed through the driver ICs. In other embodiments, the packets may be modified by a given driver IC before being passed to the next driver IC in the chain.

[0088] During the initialization phase, a brightness value can be provided to the driver IC using signal line 104. This brightness value can include multiple brightness values, each corresponding to a specific LED area 102. The driver IC can receive packets with brightness values, parse the packets to determine their corresponding brightness values, and update its target LED brightness to match the newly received brightness value. The driver IC can select an appropriate brightness value from the multiple brightness values ​​within a packet based on an allocation address received via signal path 108. A single packet with brightness values ​​can be provided to the entire LED pixel array, different packets can be provided on each bus, or different packets can be provided to each display IC column. Having more unique packets reduces the amount of data that needs to be included in each packet.

[0089] After initialization is complete, the driver IC can switch from initialization mode to normal mode (sometimes referred to as display mode). During normal mode, each driver IC controls its associated LED area 102 to emit light with a brightness received via brightness data at pin P3. To control the brightness of the LED area 102, the display IC drains a given amount of current to ground at pin P2. The display IC may include, for example, a drive transistor that controls the amount of current allowed to pass through the LEDs in area 102, and thus controls the brightness of the LEDs.

[0090] There exists that can be used for operation Figure 9 Multiple control schemes for LED arrays. In one implementation, a timing controller (TCON) can be used to control the LED array. Figure 10 This is a schematic diagram of an exemplary electronic device having a timing controller for an LED array 36 that controls a backlight 42. For example... Figure 10 As shown, electronic device 10 may include a timing controller 122 (TCON) on a substrate such as circuit board 120. Circuit board 120 may be a flexible printed circuit board or a rigid printed circuit board. Timing controller 122 may receive information from graphics processing unit 132 (GPU) on main logic board 130. In one example, main logic board 130 may be a rigid printed circuit board. GPU 132 may provide data for display 14 to timing controller 122. Timing controller 122 controls pixel array 24 and LED array 36 (for backlighting) to display data.

[0091] To control the pixel array 24, the timing controller 122 may use a display driver integrated circuit 128. The display driver integrated circuit 128 (similar to...) Figure 3 The display driver integrated circuits 62A / 62B in the pixel array 24 can be configured to adjust the liquid crystal display pixels on a per-pixel basis. The pixels can be adjusted to allow different amounts of light to pass through, thereby obtaining the desired per-pixel transparency and corresponding brightness. Each display driver integrated circuit 128 can control a corresponding subgroup of pixels in the pixel array 24.

[0092] Each display driver integrated circuit can be positioned on a corresponding flexible printed circuit 126, such as Figure 10 As shown. One or more optional sub-boards 124 may exist coupled between the flexible printed circuit 126 and the circuit board 120. Generally speaking, Figure 10The description of printed circuits 126 and 124 in the diagram is merely illustrative. Any desired connection scheme (e.g., with any desired number of intermediary circuit boards, connectors, signal lines, etc.) can be used to couple the pixel array 24 to the display driver integrated circuit 128. Similarly, any desired connection scheme (e.g., with any desired number of intermediary circuit boards, connectors, signal lines, etc.) can be used to couple the display driver integrated circuit 128 to the timing controller 122.

[0093] The timing controller 122 can control the LED array 36 to maintain synchronization with the pixel array 24. For example, for a given frame of image data, the timing controller 122 can send pixel values ​​to the display driver IC 128 of the pixel array 24 and LED brightness values ​​to the LED driver IC 82 of the LED area 102. Figure 10 In this configuration, the timing controller 122 sends signals directly to the driver IC 82 on the substrate 84. A connection structure (e.g., a flexible printed circuit) 136 may be coupled between the circuit board 120 and the LED substrate 84. The connection structure can transmit signals from the timing controller 122 to the driver 82 (and optionally from the driver 82 back to the timing controller 122).

[0094] Figure 10 The diagram also shows how the main logic board 130 may include a boost converter 134 configured to supply a power supply voltage (e.g., VLED) to the LED array 36. Figure 10 The various printed circuits shown can be electrically connected using solder, signal paths, vias, pins, etc.

[0095] The number of signal lines between the timing controller 122 and the LED array 36 is proportional to the number of driver ICs included in the LED array. As the size and density of the LED array increase, the number of driver ICs included may increase. Increasing the number of driver ICs increases the number of signal paths required. Due to the limited space available to include all desired signal paths, wiring a large number of signal paths between the timing controller 122 and the driver ICs can be challenging. When the number of LED driver ICs 82 is sufficiently small, the timing controller 122 can still send signals directly to the driver ICs. However, as the number of LED driver ICs increases, it may become preferable to provide a dedicated backlight controller for controlling the LED driver ICs 82.

[0096] Figure 11 This is a schematic diagram of an exemplary electronic device having a backlight controller for an LED array 36 that controls a backlight 42. Figure 11 The arrangement is the same as before. Figure 10The arrangement shown is the same, except that a backlight controller 138 (BCON) exists between the timing controller 122 and the LED driver IC 82. The backlight controller 138 can be mounted on a connection structure 136 (e.g., a flexible printed circuit) and can receive signals from the timing controller 122. Based on the signals from the timing controller 122, the backlight controller 138 provides signals to the driver IC 82.

[0097] The presence of the backlight controller 138 allows for a reduction in the number of signal paths between the timing controller and the LED driver IC 82. The number of signal paths between the timing controller 122 and the backlight controller 138 can also be reduced. The backlight controller 138 can provide full signal supplementation to the driver IC 82 based on the signal from the TCON. However, full signal path routing is only required in a smaller area (between the BCON and the driver IC). This reduces wiring and fan-out issues between the LED array 36 and the timing controller 122.

[0098] Figure 10 and Figure 11 The configuration shown is merely exemplary. Generally, the components of the LED array 36, pixel array 24, and corresponding control circuitry (such as BCON 138, TCON 122, GPU 132, boost converter 134) can be arranged in any desired combination on any desired number and type of substrate. These components can be electrically connected using any combination of solder, signal paths, vias, pins, etc.

[0099] exist Figure 9 In the example, each LED driver IC has four pins. Minimizing the number of pins in each driver IC advantageously minimizes the wiring on the LED substrate 84. Fewer pins in the driver IC also allow for a less complex driver IC, resulting in a smaller size and lower manufacturing cost. However, if desired, the number of pins in each driver IC can be increased to add functionality. Figure 12 This is an example of an LED array where each driver IC 82 has six pins (P1, P2, P3, P4, P5, and P6). Similar to... Figure 9 As shown, each driver IC controls the brightness of its associated LED area 102.

[0100] The functions of pins P1-P4 are as follows: Figure 12 Zhong Ke Yu Figure 9 Similar to the previous example. Pin P1 can also be used as an output pin for each driver IC 82. The LED in section 102 is coupled between power line 106 and pin P1 of the driver IC. Output pin P1 is also coupled to input pin P4 of the next driver IC in the chain, as in combination. Figure 9The discussed pin P2 can be coupled to ground. Pin P4 can receive identification information (e.g., addressing information) from controller 138 (e.g., via signal line 108). P3 can receive information similar to that in combination. Figure 9 The brightness values ​​discussed. Figure 12 The example controller shown is the backlight controller 138, which is merely illustrative. Figure 10 As shown, if needed, the driver IC 82 can be directly controlled by the timing controller 122.

[0101] exist Figure 12 In this configuration, the driver IC also has a pin P5 coupled to a bidirectional data signal line 142. The bidirectional data signal line 142 can be used to provide control signals or data from the controller 138 to the driver IC. Alternatively, the bidirectional data signal line 142 can be used to transmit feedback information from the driver IC to the controller 138. For example, the driver IC can send diagnostic information to the controller, such as a flag indicating the presence of a short circuit, or a status indicating whether the driver IC is receiving sufficient voltage. In some embodiments, the controller 138 can transmit brightness values ​​to the driver IC via bus 142 (e.g., the brightness values ​​can be provided to pin P5 instead of P3). In this type of arrangement, the P3 pin can optionally be omitted or can be used to receive different types of signals.

[0102] Controller 138 can control the transmission direction on bus 142. Controller 138 can use, for example, a switch 146 coupled between the bus (and resistor 148) and the bias voltage source terminal to control the direction of signal transmission. Controller 138 can control the state of switch 146 to control the signal transmission direction on bus 142.

[0103] exist Figure 12 In this configuration, the driver IC also has a pin P6 coupled to signal line 144. Signal line 144 can be a digital signal line used to provide a clock signal to the LED driver IC. The controller 138 can use the clock signal to control the operating timing of the driver IC.

[0104] Figure 9 and Figure 12 Each driver IC has an output pin (pin P1) for controlling the LEDs. This example is merely illustrative. If needed, the driver IC may include additional output pins to allow independent control of multiple LED zones. Figure 13 This is a schematic diagram of a driver IC with multiple output pins for controlling multiple LED zones. As shown, the LED driver IC 82 includes nine pins (P1, P2, P3, P4, P5, P6, P7, P8, and P9). Pins P1, P2, P3, P4, P5, and P6 can have various configurations as shown in the diagram. Figure 9 and Figure 12The functions discussed are the same. Pins P7, P8, and P9 can be used as additional output pins for controlling additional LED areas. For example, output pin P1 can be used to control LED area 102-1 (e.g., current flows through the LEDs in area 102-1 to ground via output pin P1 and ground pin P2). Additional output pin P7 can be used to control LED area 102-2 (e.g., current flows through the LEDs in area 102-2 to ground via output pin P7 and ground pin P2). Additional output pin P8 can be used to control LED area 102-3 (e.g., current flows through the LEDs in area 102-3 to ground via output pin P8 and ground pin P2). Additional output pin P9 can be used to control LED area 102-4 (e.g., current flows through the LEDs in area 102-4 to ground via output pin P9 and ground pin P2).

[0105] By including additional output pins, a single LED driver IC can control multiple LED zones to achieve different brightness values. For example, in Figure 13 In this configuration, LED zones 102-1, 102-2, 102-3, and 102-4 can all have a single brightness level controlled by driver IC 82. Implementing multi-zone control in this way reduces the total number of driver ICs required in the LED array. However, it increases the complexity and size of each individual driver IC. Therefore, the number of pins selected for the LED driver ICs in the display may depend on the specific design constraints of the display.

[0106] Figure 9 and Figure 12 The example of each LED zone containing 9 LEDs is merely illustrative. Generally, each LED zone can include any desired number of LEDs (e.g., a single LED, a pair of LEDs, 2 to 20 LEDs, at least 2 LEDs, at least 4 LEDs, at least 8 LEDs, less than 5 LEDs, between 4 and 12 LEDs, between 8 and 12 LEDs, between 8 and 10 LEDs, 9 LEDs, or other desired number of LEDs). Regardless of the number of LEDs in an LED zone, LEDs can be connected in series, such as in combination. Figure 9 and Figure 12 As shown and discussed.

[0107] Figure 14This is a cross-sectional side view illustrating how light-emitting diodes and driver ICs are mounted to the upper surface of a substrate. As shown, the LED array 36 includes a substrate 84 (e.g., formed of glass). Substrate 84 may sometimes be referred to as glass substrate 84 or glass layer 84. A circuit layer 150 (sometimes referred to as thin-film circuitry) may be formed on glass layer 84. Circuit layer 150 may include one or more conductive layers deposited on glass layer 84. Circuit layer 150 may be patterned to form traces following desired paths (e.g., to form as...). Figure 9 (Signal lines in the circuit). In one example, circuit layer 150 includes a first conductive layer and a second conductive layer having an intervening insulating layer. Glass layer 84 and circuit layer 150 are sometimes collectively referred to as thin film layer 152, thin film glass 152, thin film circuit layer 152, thin film circuit glass 152, glass substrate 152, LED substrate 152, glass LED substrate 152, etc. In other words, the term glass substrate can be used to refer to both a single layer of glass itself (e.g., glass substrate 84) and the combined combination of the glass layer and the conductive layer to which the LED is mounted (e.g., glass substrate 152).

[0108] like Figure 14 As shown, circuit layer 150 may include contact pads 154 (sometimes referred to as input-output contacts 154, pads 154, etc.). These contact pads can be electrically connected to mounted components via solder 160. For example... Figure 14 As shown, a light-emitting diode 38 is mounted on a glass substrate 152 and electrically connected to contact pads 154 via solder 160. Specifically, the light-emitting diode 38 has input-output contacts 156 (e.g., pins, pads, etc.) attached to the contact pads 154 using solder 160. A driver integrated circuit 82 is mounted on the glass substrate 152 and electrically connected to the contact pads 154 via solder 160. Specifically, the driver IC 82 has input-output contacts 158 (e.g., pins, pads, etc.) attached to the contact pads 154 using solder 160. Figure 14 As shown, the driver IC 82 can be mounted onto the thin-film circuit glass 152 between the LEDs 38 in the active area of ​​the display.

[0109] exist Figure 14 In this example, LED 38 and driver IC 82 can be surface mount technology (SMT) components. This example is merely illustrative, and other mounting techniques can be used to attach LED 38 and driver IC 82 to thin-film circuit glass 152. Figure 14One advantage of this arrangement is that the LED 38 and driver IC 82 can be attached to the thin-film circuit glass 152 in a single mounting step. In other words, because the LED 38 and driver IC 82 have similar dimensions and are soldered to the thin-film circuit glass in a similar manner, the attachment process for both the LED 38 and driver IC 82 can be performed simultaneously. This helps to reduce the manufacturing costs and complexity associated with LED arrays.

[0110] To improve the efficiency of the backlight, a reflective layer 162 can be formed on the upper surface of the thin-film circuit glass 152. The reflective layer 162 can be patterned to fill the portion of the upper surface of the thin-film circuit glass 152 that is not yet occupied by the LED 38 and the driver IC 82. In other words, the LED 38 and the driver IC 82 are formed in the openings of the reflective layer 162.

[0111] The reflective layer 162 can be formed of any desired material. As an example, the reflective layer can be formed of a diffuse white material (e.g., white inkjet or white ribbon). This example is merely illustrative. Generally, the reflective layer 162 can cause diffuse reflection and / or specular reflection. In diffuse reflection, incident light can be reflected in any direction. In specular reflection, incident light will be reflected at the same angle as when it was incident on the reflective material. As another example, the reflective layer 162 can be formed of a metallic coating that causes specular reflection. The reflective layer 162 can have a high reflectivity for light emitted by the LED 38 (e.g., greater than 50%, greater than 70%, greater than 80%, greater than 90%, greater than 92%, greater than 94%, greater than 96%, greater than 99%, less than 99%, etc.). The reflective layer 162 may have any desired thickness (e.g., greater than 1 micrometer, greater than 2 micrometers, greater than 3 micrometers, greater than 5 micrometers, greater than 10 micrometers, greater than 25 micrometers, less than 3 micrometers, less than 5 micrometers, less than 10 micrometers, less than 25 micrometers, less than 100 micrometers, between 3 micrometers and 15 micrometers, between 1 micrometer and 25 micrometers, etc.). The reflective layer 162 may sometimes be referred to as the white protective layer 162.

[0112] Thermal factors can also be considered in the backlight 42 with the LED array 36. Specifically, components of the LED array 36 (e.g., LEDs 38 and driver IC 82) can generate heat during operation of the display. If not carefully managed, this heat generation can adversely affect the performance of the display. The glass substrate 84 may have low thermal conductivity. Therefore, the heat generated by the components may be unevenly distributed throughout the array.

[0113] To facilitate heat distribution across the entire backlight, a thermally conductive layer 164 may be attached to the substrate 84. The thermally conductive layer 164 may have a high thermal conductivity, thus distributing heat more evenly across the entire backlight. The thermally conductive layer 164 may be formed of any desired material. The thermally conductive layer 164 may have a thermal conductivity greater than 100 W / mK, greater than 200 W / mK, greater than 300 W / mK, greater than 400 W / mK, between 100 W / mK and 400 W / mK, or another desired thermal conductivity. Examples of materials that can be used to form the thermally conductive layer 164 (sometimes referred to as the heat dissipation layer 164) include metals (e.g., copper, other metals, or combinations of copper and other metals), carbon nanotubes, graphite, or other materials with high thermal conductivity. If desired, the heat dissipation layer 164 may be formed from two or more different types of thermally conductive layers (e.g., a copper layer attached to a graphite layer, etc.). A polymer carrier film may also be incorporated into layer 164 (e.g., to support the graphite layer). In one exemplary example, the heat dissipation layer 164 includes a graphite layer interposed between two polymer carrier films.

[0114] Figure 15 and Figure 16 The diagram illustrates an additional technique for distributing heat from the backlight. Figure 15 This is a top view of an exemplary backlight 42 with an exposed conductive layer. Specifically, a reflective layer 162 may be etched around the periphery of the backlight to expose the underlying conductive layer 150-1 in the circuit layer 150. The LED 38 and driver IC 82 may also be formed in recesses in the reflective layer 162, such as... Figure 14 As shown. The exposed portion of the conductive layer 150-1 extends in a ring around the reflective layer 162. The conductive layer 150-3 can be separated from the conductive layer 150-1 through the insulating layer 150-2. The conductive layer 150-1 and the insulating layer 150-2 can be etched around the periphery of the backlight to expose the underlying conductive layer 150-3. The exposed portion of the conductive layer 150-3 extends in a ring around the conductive layer 150-1 and the reflective layer 162.

[0115] The exposed portions of conductive layers 150-1 and 150-3 can be coupled to a heat sink for additional heat dissipation. For example... Figure 15 As shown, conductive layer 150-3 is coupled to heat sink 166, and conductive layer 150-1 is coupled to heat sink 168. Heat sinks 166 and 168 can be formed of any desired material or component (e.g., components of electronic devices that provide additional functionality, such as metal housing components, dedicated heat sinks with heat sink fins, etc.). In one example, thermal paste can be used to attach the heat sinks to conductive layers 150-1 and 150-3. Heat sinks 166 and 168 are sometimes referred to as heat sink structures. Figure 15The example of conductive layers 150-1 and 150-3 being connected to a discrete heat sink is merely illustrative. In another example, the exposed conductive layers 150-1 and 150-3 of the thin-film circuit glass 152 may be coupled to a single heat sink structure.

[0116] Figure 16 yes Figure 15 A cross-sectional side view of the backlight shown. Figure 16 As shown, conductive layer 150-3 is deposited on the upper surface of glass layer 84. Insulating layer 150-2 is deposited on conductive layer 150-3. Conductive layer 150-1 is deposited on insulating layer 150-2. Reflective layer 162 is deposited on conductive layer 150-1. The exposed portion of conductive layer 150-3 is coupled to heat sink 168, and the exposed portion of conductive layer 150-1 is coupled to heat sink 166.

[0117] Apart from Figures 14 to 16 In addition to techniques for promoting heat diffusion and heat dispersion, the backlight may include a temperature sensor for active temperature sensing. For example... Figure 17 As shown, a temperature sensor 170 can be distributed on the active area of ​​the backlight on the thin-film circuit glass 152. The temperature sensor can provide temperature data to the backlight controller 138 via signal path 174. The backlight controller 138 can provide temperature data to the timing controller 122. The temperature data from the temperature sensor on the backlight allows for the determination of a 2D thermal distribution for the backlight. The 2D thermal distribution of temperature on the thin-film circuit glass 152 can be used to allow for temperature-based real-time optical compensation. For example, the performance of the LED 38 in the backlight 42 and the pixels in the pixel array 24 can depend on the operating temperature. Using the operating temperature from the 2D thermal distribution, the LEDs and pixels can be operated to present the desired brightness value under real-time temperature conditions.

[0118] Each temperature sensor can be formed using any desired technique. In one possible arrangement, temperature sensor 170 may be a four-point resistance sensor that measures temperature based on changes in the resistance of thin-film traces on thin-film circuit glass 152. In other words, the temperature sensor may be formed from metal traces on a glass substrate (e.g., deposited using physical vapor deposition or other desired techniques).

[0119] exist Figure 17 In this example, a temperature sensor 170 is formed between each group of four LEDs. This example is merely illustrative. Generally, the temperature sensor 170 can be distributed on the LED array in any desired pattern. The temperature sensors can be distributed at a uniform density or at a non-uniform density on the array. The ratio of LEDs to temperature sensors can be 4:1 (e.g., ...). Figure 17(in the middle) or any other desired ratio (e.g., 1:1, 2:1, 3:1, greater than 4:1, greater than 8:1, greater than 10:1, greater than 25:1, greater than 50:1, less than 8:1, less than 10:1, less than 25:1, less than 50:1, less than 100:1, between 1:1 and 10:1, between 2:1 and 5:1, between 4:1 and 100:1, etc.).

[0120] The backlight may also include optical sensors for real-time sensing of LED brightness and / or color. For example... Figure 17 As shown, optical sensors 172 can be distributed on the active region of the backlight on the thin-film circuit glass 152. The optical sensors can provide optical data to the backlight controller 138 via signal path 174. The backlight controller 138 can provide optical data to the timing controller 122. The optical data from the optical sensors on the backlight allows for the determination of a 2D distribution of brightness and color for the backlight. The 2D optical distribution on the thin-film circuit glass 152 can be used to allow for real-time optical compensation. For example, the operation of LEDs and pixels can illustrate real-time optical conditions. As a non-limiting example, the optical sensors can provide data indicating that a given LED has a brightness below a desired value. In response, the timing controller can increase the brightness of that LED until a target brightness level is reached. Each optical sensor can include any desired components for measuring brightness levels. Optical sensors can have multiple color channels; different optical sensors can have different color channels; all optical sensors can have the same single color channel, and so on.

[0121] exist Figure 17 In this example, an optical sensor 172 is formed between each group of four light-emitting diodes. This example is merely illustrative. In general, the optical sensor 172 can be distributed on the LED array in any desired pattern. The optical sensor can be distributed at a uniform density or at a non-uniform density on the array. The ratio of LEDs to optical sensors can be 4:1 (e.g., ...). Figure 17 (in the middle) or any other desired ratio (e.g., 1:1, 2:1, 3:1, greater than 4:1, greater than 8:1, greater than 10:1, greater than 25:1, greater than 50:1, less than 8:1, less than 10:1, less than 25:1, less than 50:1, less than 100:1, between 1:1 and 10:1, between 2:1 and 5:1, between 4:1 and 100:1, etc.).

[0122] In addition, Figure 17In this example, there are an equal number of temperature sensors 170 and optical sensors 172. This example is merely illustrative. In general, the number and location of the temperature and optical sensors can be selected independently. Therefore, different numbers of temperature and optical sensors can be present if needed, and the temperature and optical sensors can be positioned in different patterns on the active area if desired.

[0123] In addition to the reflective layer (162) on the upper surface of the thin-film circuit glass 152, a reflective layer may be included on the lower surface of the thin-film circuit glass 152. Figure 18 This is a cross-sectional side view of an exemplary backlight source including a reflective layer attached to the lower surface of the thin-film circuit glass 152. As shown, the reflective layer 176 is attached to the lower surface of the thin-film circuit glass 152. The reflective layer 176 can increase the efficiency of the backlight source by reflecting light from the light-emitting diode 38.

[0124] As previously combined Figure 14 As discussed, LED 38 can be attached to input-output contacts 154 in circuit layer 150 via solder 160. LED 38 can emit light in direction 182 (e.g., towards the viewer via pixel array 24). However, LED 38 can also emit light in direction 184 (away from the pixel array and the viewer). Without reflective layer 176, light emitted in direction 184 may be lost within the electronic device and fail to reach the viewer. To avoid this inefficiency, reflective layer 176 is present to redirect light in direction 182 back through the pixel array. Reflective layer 176 is attached to the side of glass substrate 84 opposite to LED 38 and driver IC 82.

[0125] The reflective layer 176 can be formed of any desired material. As an example, the reflective layer can be formed of a diffuse white material (e.g., white inkjet or white ribbon). This example is merely illustrative. As another example, the reflective layer 176 can be formed of a metallic coating. Generally, the reflective layer 176 can cause diffuse reflection and / or specular reflection. The reflective layer 176 can have a high reflectivity for light emitted by the LED 38 (e.g., greater than 50%, greater than 70%, greater than 80%, greater than 90%, greater than 92%, greater than 94%, greater than 96%, greater than 99%, less than 99%, etc.). The reflective layer 176 can have any desired thickness (e.g., greater than 1 micrometer, greater than 2 micrometers, greater than 3 micrometers, greater than 5 micrometers, greater than 10 micrometers, greater than 25 micrometers, less than 3 micrometers, less than 5 micrometers, less than 10 micrometers, less than 25 micrometers, less than 100 micrometers, between 3 micrometers and 15 micrometers, between 1 micrometer and 25 micrometers, between 1 micrometer and 5 micrometers, etc.). The reflective layer 176 may be a coating or a strip. The reflective layer 176 may sometimes be described as a reflective coating 176 or a reflective strip 176.

[0126] Figure 19 This is a cross-sectional side view of a backlight source including both the reflective layer and the thermally conductive layer attached to the lower surface of the glass substrate. (Example) Figure 19 As shown, the reflective layer 176 can be attached to the lower surface of the glass substrate 84. The reflective layer 176 can increase the optical efficiency of the backlight unit. Additionally, the thermally conductive layer 164 (as combined with...) Figure 14 The reflective layer 176 is attached to the reflective layer 176 such that it is inserted between the lower surface of the glass substrate 84 and the thermally conductive layer 164. In addition to the efficiency benefits from the reflective layer 176, the thermally conductive layer 164 provides heat dissipation benefits.

[0127] In yet another example, such as Figure 20 As shown in the cross-sectional side view, a single reflective thermal conductive layer 178 can be attached to the lower surface of the glass substrate 84 (instead of...). Figure 19 (Separated reflective heat-conducting layers 176 / 164). The reflective heat-conducting layer 178 may have a high reflectivity to increase the efficiency of the backlight. For example, the reflective heat-conducting layer 178 may have a reflectivity greater than 50%, greater than 70%, greater than 80%, greater than 90%, greater than 92%, greater than 94%, greater than 96%, greater than 99%, less than 99%, etc. In addition, the reflective heat-conducting layer 178 may have a high thermal conductivity to achieve the desired heat dissipation performance. The heat-conducting layer 178 may have a thermal conductivity greater than 100 W / mK, greater than 200 W / mK, greater than 300 W / mK, greater than 400 W / mK, between 100 W / mK and 400 W / mK, or another desired thermal conductivity.

[0128] Figure 21 This is a cross-sectional side view illustrating an exemplary backlight source from which a glass substrate can be formed from white diffuse glass. Instead of transparent glass with high transparency, white diffuse glass 84W can be used as a substrate for thin-film circuit glass 152. White diffuse glass 84W may include dispersed particles 186 (e.g., scattering particles) to achieve the desired light diffusion. The reflectivity of white diffuse glass 84W may be greater than 20%, greater than 30%, greater than 40%, greater than 50%, greater than 70%, greater than 80%, greater than 90%, greater than 92%, greater than 94%, greater than 96%, greater than 99%, less than 99%, etc.

[0129] LED driver IC 82 is distributed over the active area of ​​the backlight between LEDs 38. Driver IC 82 does not emit light and covers other reflective treatments on the thin-film circuit glass 152 (e.g., driver IC 82 prevents light from reaching reflective layers 162, 176, etc.). The driver IC may be visible if not carefully observed (e.g., as a shadow on the display when a pure white image is required). To prevent the driver IC from causing visible artifacts in the display and to improve the efficiency of the backlight, the driver IC may have a reflective upper surface.

[0130] Figure 22 This is a cross-sectional side view of an exemplary backlight with a driver IC having a reflective upper surface. (Example:) Figure 22 As shown, a reflective layer 180 may be formed on the upper surface 188 of the driver IC 82. The reflective layer 180 may be formed of any desired material. As an example, the reflective layer 180 may be formed of a diffuse white material (e.g., white inkjet or white ribbon). As another example, the reflective layer 180 may be a metallic coating. Generally, the reflective layer 180 may cause diffuse reflection and / or specular reflection. The reflective layer 180 may have a high reflectivity (e.g., greater than 50%, greater than 70%, greater than 80%, greater than 90%, greater than 92%, greater than 94%, greater than 96%, greater than 99%, less than 99%, etc.). The reflective layer 180 may have any desired thickness (e.g., greater than 1 micrometer, greater than 2 micrometers, greater than 3 micrometers, greater than 5 micrometers, greater than 10 micrometers, greater than 25 micrometers, less than 3 micrometers, less than 5 micrometers, less than 10 micrometers, less than 25 micrometers, less than 100 micrometers, between 3 micrometers and 15 micrometers, between 1 micrometer and 25 micrometers, etc.).

[0131] Figure 22 The example of a separate reflective layer 180 formed on the driver IC 82 is merely illustrative. In another illustrative example, the upper surface 188 of the IC itself may be polished to increase the reflectivity of the upper surface. In this type of arrangement, the reflectivity of the upper surface 188 may be greater than 50%, greater than 70%, greater than 80%, greater than 90%, greater than 92%, greater than 94%, greater than 96%, greater than 99%, less than 99%, etc. When the driver IC 82 does indeed have a separate reflective layer 180, the upper surface of the reflective layer 180 can be considered the upper surface of the driver IC (e.g., because the reflective layer effectively forms the upper surface).

[0132] Figure 23 This is a top view of an exemplary LED array showing possible LED layouts. As shown, the LEDs 38 can be arranged according to a zigzag grid (e.g., a non-square grid) instead of a uniform square grid. In a uniform square grid, the LEDs can be arranged in straight columns and rows (e.g., similar to...). Figure 4 (As shown). However, during display operation, this type of arrangement can cause visible artifacts such as grid blurring. Visible artifacts can be caused by the periodicity of a uniform square grid. Therefore, arranging LEDs as shown... Figure 23 The non-square grid in the image can reduce periodicity and mitigate visible artifacts.

[0133] like Figure 23 As shown, LEDs can be arranged according to a zigzag grid line 190. The LEDs are arranged into multiple rows (“R”) and multiple columns (“C”). In a given row, the grid lines defining the arrangement of the LEDs can follow a zigzag pattern (e.g., instead of straight lines, the grid lines have multiple line segments at angles relative to each other). The grid lines defining a row of LEDs can be referred to as horizontal grid lines. Similarly, in a given column, the grid lines defining the arrangement of the LEDs can follow a zigzag pattern (e.g., instead of straight lines, the grid lines have multiple line segments at angles relative to each other). The grid lines defining a column of LEDs can be referred to as vertical grid lines.

[0134] The resulting pattern has horizontal and vertical grid lines that intersect each other at different angles. For example, at some points, the grid lines are perpendicular to each other (e.g., angle 194). However, at other points, the grid lines are acute to each other (e.g., acute angle 192). At still other points, the grid lines are obtuse to each other (e.g., obtuse angle 196). Angles 192 and 196 can be complementary angles.

[0135] exist Figure 23 In this configuration, the horizontal and vertical grid lines form a zigzag pattern. Therefore, LEDs can be described as being arranged with a non-square or non-rectangular grid (e.g., the grid lines do not form rectangles). Consequently, rows of LEDs can be referred to as zigzag rows, rows following a zigzag pattern, or non-linear rows. Similarly, columns of LEDs can therefore be referred to as zigzag columns, columns following a zigzag pattern, or non-linear columns. Because... Figure 23 The zigzag pattern allows for a variety of different distances between adjacent LEDs within the display. For example, some LEDs may be separated from their diagonally opposite counterparts by a distance D1 (e.g., in adjacent rows and columns). Other LEDs may be separated from their diagonally opposite counterparts by a distance D2 or D3. D3 may be less than D1, and the latter may be less than D2. This contrasts with a square grid, where the distance between each LED and its diagonally opposite counterpart is uniform across the LED array.

[0136] Figure 23 The example of the zigzag grid lines used to mitigate periodicity is merely illustrative. The grid lines and LEDs can be arranged in hexagons, octagons, or any other desired configuration if desired. Dithering can also be used to increase the variation in the LED positions on the array.

[0137] Figure 24 This is a top view of an exemplary LED array with another possible LED layout. Figure 24 In the middle, each 3×3 LED group (sometimes referred to as LED area 102) is relative to Figure 23 The LED array in this design has a reduced footprint. Similar to... Figure 23 As shown, Figure 24 The grid lines 190 in the text include horizontal Z-shaped grid lines and vertical Z-shaped grid lines. However, in Figure 23 In the diagram, the LED is positioned at the intersection of the horizontal and vertical Z-shaped grid lines. Figure 24 In this configuration, only the central LED 38C is positioned at the intersection of the horizontal and vertical Z-shaped grid lines. The peripheral LEDs of the group (38P) move in direction 198 from the grid line intersection towards the central LED 38C.

[0138] This arrangement of LEDs effectively reduces the surface area occupied by each LED group. Therefore, the distance between each adjacent LED group is larger (e.g., ...). Figure 24 The distance between groups in the middle is greater than 200. Figure 23 (The distance between groups in the image). Having smaller LED areas can improve backlight performance by mitigating the halo effect. The halo effect refers to the phenomenon that occurs when a small area on a display is designed to have high brightness and is surrounded by a low-brightness area (e.g., stars in the night sky). Ideally, the low-brightness area should be able to be controlled completely independently of the high-brightness area. However, if both the intended high-brightness and low-brightness areas occupy the area of ​​one LED area, a bright "halo" will exist in the intended low-brightness area (because the LED area is set to high brightness for the high-brightness area on the display). Reducing the area of ​​each LED area can mitigate this halo effect (because the resolution is higher only in the intended area where the intended backlight brightness level is expected).

[0139] The LED regions of the LED array 36 can be optimized to achieve a target energy distribution. Figure 25 This is a graph illustrating an exemplary energy distribution of brightness as a function of the positions of two LED regions. As shown, the brightness follows distribution 202, with each corresponding LED region having a peak. The distance between the peaks of adjacent LED regions is shown as spacing 206. Another relevant property of this distribution is distance 204, which is the width of the peak (referred to herein as full width at half maximum or FW) when the brightness is half the maximum brightness of the peak. The ratio of spacing 206 (P) to distance 204 (FW) can be a key property of LED regions in a backlight. LED regions in backlight 42 (e.g., Figure 9 , Figure 12 , Figure 23 , Figure 24The P / FW of the region (e.g., the region) can be less than 1.3, less than 1.2, less than 1.1, greater than 1, between 1.05 and 1.2, between 1.05 and 1.15, between 1.01 and 1.2, etc. Figure 25 The distribution shape depicted is merely illustrative. The brightness distribution of a given LED area can follow any desired shape.

[0140] To achieve the desired emission distribution, a larger current can be used to drive the center LED of a given LED area than the surrounding LEDs. Figure 26 This is a top view of an exemplary LED array showing how a first LED in the first zone 102-A can be driven using a different current than that in the second zone 102-B. Using a higher current to drive the center LED (“A”) optimizes the emission distribution of the 3×3 LED group. A single driver IC 82 can be used to drive both zones 102-A and 102-B, or two discrete driver ICs can be used to drive both zones. Although the LEDs in zones 102-A and 102-B are driven with different currents and are therefore referred to as different zones, the 3×3 LED group can still be designed to work together to achieve the desired emission distribution. Therefore, the 3×3 group can still be referred to as a single LED group or LED unit.

[0141] In the LED group formed by LED zones 102-A and 102-B, the ratio of the current between the peripheral LEDs (“B”) and the central LED (“A”) can be constant. In other words, the LED group can still have a single target brightness value, and the driver IC can apply current at a predetermined ratio to achieve the target brightness and optimized emission distribution. Figure 26 The example of a center LED having a different current (brightness) than the surrounding LEDs is merely illustrative. Generally, any LED within a group can have a unique brightness to facilitate adjusting the emission distribution as needed.

[0142] In this document, an LED array with a driver IC in the active region is described as serving as a backlight for a pixel array (e.g., a liquid crystal pixel array). It should be noted that, if desired, an arrangement of the type shown herein can be used to form a stand-alone display (e.g., without external LCD pixels). The LEDs can form display pixels controlled by the driver IC in the active region.

[0143] According to one embodiment, an electronic device is provided, comprising a plurality of pixels and a backlight configured such that the plurality of pixels generate backlight illumination. The backlight has an active region and includes: a substrate having a surface; a light-emitting diode array mounted on the surface of the substrate in the active region, the light-emitting diode array overlapping the plurality of pixels; and a plurality of driver integrated circuits mounted on the surface of the substrate in the active region, each driver integrated circuit controlling the brightness of a corresponding subgroup of the light-emitting diode array.

[0144] According to another embodiment, the substrate is a glass substrate.

[0145] According to another implementation, multiple driver integrated circuits are arranged in one or more interconnect chains.

[0146] According to another implementation, within each interconnect chain, the output from each driver integrated circuit is provided as an input to the next driver integrated circuit.

[0147] According to another implementation, each driver integrated circuit has multiple input-output contacts.

[0148] According to another implementation, each of the multiple input-output contacts is soldered to a circuit layer on the surface of the substrate.

[0149] According to another embodiment, each of the light-emitting diodes has a corresponding input-output contact of a circuit layer that is soldered to the surface of a substrate.

[0150] According to another embodiment, the plurality of input-output contacts for each driver integrated circuit include a first input-output contact configured to receive digital address information.

[0151] According to another embodiment, the multiple input-output contacts for each driver integrated circuit include a second input-output contact configured to receive brightness information of a digital light-emitting diode.

[0152] According to another embodiment, the plurality of input-output contacts for each driver integrated circuit include a third input-output contact configured to provide digital output address information for a subsequent driver integrated circuit and electrically connected to a corresponding subgroup of the light-emitting diode array of the driver integrated circuit.

[0153] According to another embodiment, the plurality of input-output contacts for each driver integrated circuit include a fourth input-output contact electrically connected to ground.

[0154] According to another embodiment, the plurality of input-output contacts for each driver integrated circuit include a first input-output contact coupled to a bidirectional data bus.

[0155] According to another embodiment, each driver integrated circuit includes an output pin, and the light-emitting diodes in a corresponding subgroup of the light-emitting diode array for the driver integrated circuit are connected in series between the output pin and the power supply line.

[0156] According to another embodiment, each driver integrated circuit includes at least two output pins, and the light-emitting diodes in a corresponding subgroup of the light-emitting diode array for the driver integrated circuit include at least a first group of light-emitting diodes and a second group of light-emitting diodes, each of the at least first group of light-emitting diodes and the second group of light-emitting diodes being coupled between a corresponding output pin of the at least two output pins and a power supply line.

[0157] According to another embodiment, the multiple pixels include multiple liquid crystal display pixels.

[0158] According to one embodiment, an electronic device is provided, the electronic device including a plurality of pixels and a backlight, the backlight being configured such that the plurality of pixels generate backlight illumination, the backlight comprising: a glass thin-film circuit layer including at least one conductive layer on a glass substrate; a two-dimensional array of light-emitting diodes mounted on an upper surface of the glass thin-film circuit layer, the two-dimensional array of light-emitting diodes being arranged in a two-dimensional array of corresponding cells; and a driver integrated circuit mounted on the upper surface of the glass thin-film circuit layer, the driver integrated circuit being distributed among the two-dimensional array of light-emitting diodes.

[0159] According to another embodiment, the backlight includes a plurality of digital signal lines configured to provide digital signals to a driver integrated circuit.

[0160] According to another embodiment, the backlight includes a power line, a two-dimensional array of light-emitting diodes arranged in multiple groups of light-emitting diodes, and each group of light-emitting diodes is coupled between a corresponding driver integrated circuit and the power line.

[0161] According to one embodiment, the electronic device includes: a substrate; a two-dimensional array of light-emitting diodes mounted on a top surface of the substrate; and a driver integrated circuit mounted on the top surface of the substrate, the driver integrated circuit being positioned within an area defined by the two-dimensional array of light-emitting diodes, each driver integrated circuit controlling at least one light-emitting diode in the two-dimensional array of light-emitting diodes, and the driver integrated circuits being arranged in a plurality of daisy-chain groups.

[0162] According to another embodiment, the substrate is a glass substrate.

[0163] According to one embodiment, an electronic device is provided, the electronic device including a plurality of pixels and a backlight configured such that the plurality of pixels generate backlight illumination, the backlight comprising: a glass substrate having opposing first and second surfaces; a light-emitting diode array mounted on the first surface of the glass substrate, the light-emitting diode array overlapping with the plurality of pixels; a driver integrated circuit mounted on the first surface of the glass substrate, each driver integrated circuit controlling at least one light-emitting diode in the light-emitting diode array; and a thermally conductive layer attached to the second surface of the glass substrate.

[0164] According to another embodiment, the backlight has an active region, and each driver integrated circuit is located within the active region.

[0165] According to another embodiment, the light-emitting diode array includes a two-dimensional array of light-emitting diodes, and a driver integrated circuit is distributed within the two-dimensional array of light-emitting diodes.

[0166] According to another embodiment, the electronic device includes a controller configured to provide digital signals to a driver integrated circuit.

[0167] According to another implementation, the controller is a timing controller configured to provide digital signals directly to the driver integrated circuit.

[0168] According to another embodiment, the controller is a backlight controller, and the electronic device includes a timing controller configured to provide control signals to the backlight controller, which is configured to provide digital signals directly to the driver integrated circuit based on the control signals.

[0169] According to another implementation, the thermally conductive layer has a thermal conductivity greater than 100 W / mK.

[0170] According to another embodiment, the thermally conductive layer is a reflective thermally conductive layer with a reflectivity of greater than 80%.

[0171] According to another embodiment, the thermally conductive layer comprises graphite.

[0172] According to another embodiment, the backlight includes a reflective layer inserted between a thermally conductive layer and a second surface of a glass substrate.

[0173] According to one embodiment, an electronic device is provided, comprising a plurality of pixels and a backlight configured such that the plurality of pixels generate backlight illumination, the backlight comprising a substrate; a two-dimensional array of light-emitting diodes mounted on the substrate, the two-dimensional array of light-emitting diodes arranged in a two-dimensional array of corresponding units; a driver integrated circuit mounted on the substrate, each driver integrated circuit controlling at least one unit; a sensor mounted on the substrate, the sensor being distributed among the two-dimensional array of light-emitting diodes; and a controller configured to control the two-dimensional array of light-emitting diodes at least in part based on information from the sensor.

[0174] According to another embodiment, the backlight has an active region, and each driver integrated circuit is located within the active region.

[0175] According to another implementation, the driver integrated circuit is distributed in a two-dimensional array of light-emitting diodes.

[0176] According to another embodiment, the sensor includes a temperature sensor configured to measure the temperature associated with at least a portion of the backlight.

[0177] According to another embodiment, the sensor includes an optical sensor configured to measure the light output from at least one of the light-emitting diodes in a two-dimensional array of light-emitting diodes.

[0178] According to another implementation, the sensor includes a temperature sensor and an optical sensor.

[0179] According to one embodiment, an electronic device is provided, the electronic device including a plurality of pixels and a backlight configured such that the plurality of pixels generate backlight illumination, the backlight including: a glass thin film circuit layer including a conductive layer on a glass substrate; a two-dimensional array of light-emitting diodes mounted on an upper surface of the glass thin film circuit layer; a driver integrated circuit mounted on the upper surface of the glass thin film circuit layer; and a heat sink structure coupled to an exposed portion of the conductive layer.

[0180] According to another embodiment, the conductive layer is a first conductive layer, and the glass thin film circuit layer includes a second conductive layer and an insulating layer interposed between the first and second conductive layers.

[0181] According to another implementation, the exposed portion of the second conductive layer is coupled to an additional heat sink structure.

[0182] According to another implementation, the driver integrated circuit is distributed in a two-dimensional array of light-emitting diodes.

[0183] According to one embodiment, an electronic device is provided, the electronic device including a plurality of pixels and a backlight configured such that the plurality of pixels generate backlight illumination, the backlight comprising: a substrate having a upper surface; a reflective layer formed on the upper surface of the substrate, the reflective layer having a plurality of openings; a light-emitting diode array mounted on the upper surface of the substrate, the light-emitting diode array overlapping with the plurality of pixels; and a driver integrated circuit mounted on the upper surface of the substrate, each driver integrated circuit controlling at least one light-emitting diode in the light-emitting diode array, and each light-emitting diode and each driver integrated circuit being positioned within a corresponding opening in the plurality of openings.

[0184] According to another embodiment, the backlight has an active region, and each driver integrated circuit is located within the active region.

[0185] According to another embodiment, the light-emitting diode array includes a two-dimensional array of light-emitting diodes, and a driver integrated circuit is distributed within the two-dimensional array of light-emitting diodes.

[0186] According to another embodiment, the backlight includes an additional reflective layer attached to the lower surface of the substrate.

[0187] According to another embodiment, the backlight includes a thermally conductive layer attached to an additional reflective layer, which is interposed between the lower surface of the substrate and the thermally conductive layer.

[0188] According to another embodiment, the additional reflective layer is a reflective thermally conductive layer having a thermal conductivity greater than 100 W / mK and a reflectivity greater than 80%.

[0189] According to another embodiment, the substrate includes a white diffused glass layer.

[0190] According to another implementation, the upper surface of each driver integrated circuit has a reflectivity greater than 80%.

[0191] According to another embodiment, each driver integrated circuit includes an additional reflective layer covering the respective top surface of the driver integrated circuit.

[0192] According to another embodiment, the light-emitting diode array is a two-dimensional array of light-emitting diodes arranged in a two-dimensional array of corresponding units, each unit including multiple light-emitting diodes, and the spacing between adjacent light-emitting diodes within a given unit is smaller than the spacing between adjacent units.

[0193] According to another embodiment, the light-emitting diode array is a two-dimensional array of light-emitting diodes arranged in multiple zigzag columns and multiple zigzag rows.

[0194] According to one embodiment, an electronic device is provided, the electronic device including a plurality of pixels and a backlight, the backlight being configured such that the plurality of pixels generate backlight illumination, the backlight including: a substrate; a two-dimensional array of light-emitting diodes mounted on the substrate, the two-dimensional array of light-emitting diodes including a plurality of non-linear rows and a plurality of non-linear columns; and a driver integrated circuit mounted on the substrate, each driver integrated circuit controlling at least one light-emitting diode in the two-dimensional array of light-emitting diodes.

[0195] According to another embodiment, the backlight has an active region, and each driver integrated circuit is located within the active region.

[0196] According to another implementation, the driver integrated circuit is distributed in a two-dimensional array of light-emitting diodes.

[0197] According to another implementation, the multiple non-linear rows include multiple zigzag rows, and the multiple non-linear columns include multiple zigzag columns.

[0198] According to another embodiment, there are at least three discrete interval sizes between diagonally adjacent light-emitting diodes in a two-dimensional array of light-emitting diodes.

[0199] According to another embodiment, the two-dimensional array of light-emitting diodes is arranged in a two-dimensional array of corresponding units, each unit including multiple light-emitting diodes, and the spacing between adjacent light-emitting diodes within a given unit is smaller than the spacing between adjacent units.

[0200] According to another embodiment, the two-dimensional array of light-emitting diodes is arranged in a two-dimensional array of corresponding units, each unit including a plurality of light-emitting diodes arranged in a 3×3 manner, and the central light-emitting diode of each unit is configured to be driven with a higher brightness than the peripheral light-emitting diodes in that unit.

[0201] According to one embodiment, an electronic device is provided, the electronic device including a plurality of pixels and a backlight, the backlight being configured such that the plurality of pixels generate backlight illumination, the backlight comprising: a substrate; a two-dimensional array of light-emitting diodes mounted on the substrate; a driver integrated circuit mounted on the substrate, each driver integrated circuit controlling at least one light-emitting diode of the two-dimensional array of light-emitting diodes and having a corresponding top surface; and a plurality of reflective layers, each reflective layer formed on the top surface of the respective driver integrated circuit.

[0202] According to another implementation, the driver integrated circuit is distributed in a two-dimensional array of light-emitting diodes.

[0203] The foregoing description is merely illustrative, and various modifications can be made by those skilled in the art without departing from the scope and substance of the described embodiments. The aforementioned embodiments can be implemented independently or in any combination.

Claims

1. An electronic device, comprising: Multiple pixels; and A backlight source, configured to generate backlight illumination by the plurality of pixels, wherein the backlight source has an active region and includes: A substrate, the substrate having a surface; A light-emitting diode array mounted on the surface of the substrate, wherein the light-emitting diode array is arranged in rows and columns forming the active region, and wherein the light-emitting diode array overlaps with the plurality of pixels; A plurality of driver integrated circuits are mounted on the surface of the substrate in the active region, wherein each driver integrated circuit controls the brightness of a corresponding subgroup of the light-emitting diode array; A conductive layer, said conductive layer being attached to said surface of said substrate; and A heat sink structure coupled to the exposed surface of the conductive layer.

2. The electronic device according to claim 1, wherein the substrate is a glass substrate, the conductive layer is a thermally conductive layer, and the backlight further comprises: Multiple reflective layers, each of which is formed on the top surface of a corresponding driver integrated circuit.

3. The electronic device of claim 1, wherein the plurality of driver integrated circuits are arranged in one or more interconnect chains, and wherein, Within each interconnect chain, the output from each driver integrated circuit is provided as an input to the next driver integrated circuit.

4. The electronic device of claim 1, wherein each driver integrated circuit has a plurality of input-output contacts, wherein each of the plurality of input-output contacts is soldered to a circuit layer on the surface of the substrate, and wherein each of the light-emitting diodes has a corresponding input-output contact soldered to the circuit layer on the surface of the substrate.

5. The electronic device of claim 1, wherein each driver integrated circuit has a plurality of input-output contacts, wherein the plurality of input-output contacts for each driver integrated circuit comprises: The first input-output contact is configured to receive digital address information; The second input-output contact is configured to receive brightness information from a digital light-emitting diode. A third input-output contact is configured to provide digital output address information to a subsequent driver integrated circuit and is electrically connected to the corresponding subgroup of the light-emitting diode array for the driver integrated circuit; and The fourth input-output contact is electrically connected to ground.

6. The electronic device of claim 1, wherein each driver integrated circuit has a plurality of input-output contacts, and wherein the plurality of input-output contacts for each driver integrated circuit comprises: The first input-output contact is coupled to the bidirectional data bus.

7. The electronic device of claim 1, wherein each driver integrated circuit includes an output pin, and wherein the light-emitting diodes in the respective subgroup of the light-emitting diode array for the driver integrated circuit are connected in series between the output pin and the power supply line.

8. The electronic device of claim 1, wherein each driver integrated circuit includes at least two output pins, wherein the light-emitting diodes in the respective subgroups of the light-emitting diode array for the driver integrated circuit include at least a first group of light-emitting diodes and a second group of light-emitting diodes, the at least first group of light-emitting diodes and the second group of light-emitting diodes are each coupled between a respective output pin of the at least two output pins and a power line, and wherein the plurality of pixels includes a plurality of liquid crystal display pixels.

9. An electronic device, comprising: Multiple pixels; and A backlight, configured to generate backlight illumination by the plurality of pixels, wherein the backlight includes: A glass thin-film circuit layer, the glass thin-film circuit layer comprising at least one conductive layer on a glass substrate; A two-dimensional array of light-emitting diodes (LEDs) mounted on the upper surface of the glass thin-film circuit layer, wherein the two-dimensional array of LEDs is arranged in a two-dimensional array of corresponding units, wherein each unit includes a plurality of LEDs; and A driver integrated circuit is mounted on the upper surface of the glass thin-film circuit layer, wherein the driver integrated circuit is distributed in the two-dimensional array of light-emitting diodes.

10. The electronic device of claim 9, wherein the backlight comprises: Multiple digital signal lines are configured to provide digital signals to the driver integrated circuit.

11. The electronic device of claim 9, wherein the backlight further includes a power line, wherein the two-dimensional array of light-emitting diodes is arranged in a plurality of light-emitting diode groups, and wherein each light-emitting diode group is coupled between a corresponding driver integrated circuit and the power line.

12. An electronic device, comprising: substrate; A two-dimensional array of light-emitting diodes, wherein the two-dimensional array of light-emitting diodes is mounted on the upper surface of the substrate; and A driver integrated circuit is mounted on the upper surface of the substrate, wherein the driver integrated circuit is positioned within an area defined by a two-dimensional array of light-emitting diodes, wherein each driver integrated circuit controls at least one light-emitting diode in the two-dimensional array of light-emitting diodes, and wherein the driver integrated circuits are arranged in a plurality of daisy-chain groups.

13. The electronic device of claim 12, wherein the substrate is a glass substrate.

14. An electronic device comprising: Multiple pixels; and A backlight source, configured to generate backlight illumination by the plurality of pixels, wherein the backlight source has an active region and includes: A glass substrate having opposing first and second surfaces; A light-emitting diode array mounted on the first surface of the glass substrate, wherein the light-emitting diode array is arranged in rows and columns forming the active region, and wherein the light-emitting diode array overlaps with the plurality of pixels; A driver integrated circuit is mounted on the first surface of the glass substrate in the active region, wherein each driver integrated circuit controls at least one light-emitting diode in the light-emitting diode array; A thermally conductive layer is attached to the second surface of the glass substrate; and A reflective layer is inserted between the thermally conductive layer and the second surface of the glass substrate.

15. The electronic device of claim 14, wherein the thermally conductive layer has a thermal conductivity greater than 100 W / mK.

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