Service Life Extension in Micro-LED Displays

Micro LED displays with improved yield and durability by using micro LED chips with rounded corners. The micro LED chips have an n-sided polygonal shape with rounded corners instead of sharp corners. The rounded corners have a radius of curvature of 0.5 microns or more. This reduces the risk of damage during transfer and handling of the tiny LEDs.

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Display device with improved connection reliability for micro LEDs, and a fabrication method. The display has electrodes, a bonding pattern with high aspect ratio conductive particles, and micro LEDs on the bonding pattern. The high aspect ratio conductive particles provide dense electrical connection between the micro LEDs and electrodes, improving reliability. The bonding pattern is formed by selectively removing vertical aligned conductive particles from a layer on the electrode using photolithography without a separate photoresist.

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Display device with improved heat dissipation between the display panel and circuit substrates using a heat dissipation sheet with liquid metal flow paths. The sheet is sandwiched between the display panel and circuit substrates. The liquid metal flows through the path patterns to dissipate heat generated by the circuitry. The density and flow control of the liquid metal paths can be adjusted to optimize heat dissipation based on the location of high temperature areas. This prevents trapped heat in the gap between substrates and improves display reliability and lifespan.

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Display device design with improved encapsulation for preventing contaminant penetration between the display layers. The display has a bank layer with tips extending over the electrode openings. An encapsulation layer covers the display areas, but leaves cavities between the bank layer tips and encapsulation. These cavities provide a penetration path for contaminants. To prevent this, the encapsulation layer has a sub-layer that contacts the bank layer below the tips, sealing off the cavities. This prevents impurities from entering the display stack through the openings.

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Reducing current density and heat generation in display panels with integrated touch screens to prevent melting or ignition of polarization layers. The solution involves a unique electrode design for the cathode common electrode and touch electrodes. Instead of a single cathode common electrode connecting to the display and non-display areas, a separate line electrode is added in between. This line electrode has a larger area and connects the cathode common electrode in the non-display region to the touch electrodes. This distributes the current more evenly and reduces the current density and heat generation at the bottleneck between the display and non-display areas.

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Display device with reduced lateral moisture penetration to improve reliability and display quality. The display has a protruding portion on the encapsulation substrate that extends into the non-display area around the main display area. This protruding portion blocks moisture penetration through the side surfaces of the display. The bonding layer between the substrate and encapsulation substrate is excluded around the protruding portion to minimize moisture trapping. This prevents moisture from being sandwiched between the substrates and propagating to the display area.

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Flexible display device with improved durability and bendability. The display has a support substrate beneath the display panel with rigid sections spaced apart by an elastic portion. The rigid sections have curved surfaces with protrusions and recesses. This disperses bending forces to prevent damage to the display components. The curved sections reduce stress concentrations when flexing the display. The protrusions and recesses on the rigid sections allow the elastic portion to fill gaps between them.

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Display and electronic device with reduced power consumption for still images while maintaining consistent color. The display uses a microLED with a control circuit that includes a triangular wave generator, comparator, switches, and transistors. When displaying a still image, the first transistor retains the data potential. A triangular wave is output to the pixels. The comparator generates an output signal based on the retained potential and triangular wave. Switches control the microLED current based on the output signal. This allows the microLED to continue emitting at reduced brightness without PWM when the display is static.

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Display device with low power consumption and long-term use in dark environments. It uses a thin film transistor with a highly purified intrinsic oxide semiconductor channel layer. This oxide semiconductor has very low impurity concentration and defect density, allowing stable transistor operation with very low off-state current. This enables pixel circuits without capacitors, increasing aperture ratio and reducing power consumption. In self-luminous displays, the low off-state current allows driving the pixel light source with reduced voltage. The display can also stop signal output during still images to further lower power consumption. The highly purified oxide semiconductor also enables long-term use in dark environments by reducing light storage requirements.

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LED screen display correction method and system to improve display brightness and extend screen life. The method involves dynamically adjusting the temperature of the LED screen's light condensing elements instead of increasing luminous power when brightness decreases. This prevents high power consumption that shortens screen life. The method obtains the LED element parameters, calculates brightness attenuation and initial floating values, then corrects the floating value based on environmental factors. If brightness is still below target, the screen temperature is adjusted to compensate.

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LED chips with improved reliability, moisture resistance, and flexibility for additional features by using a passivation layer around the mesa sidewalls of the LED structure. The passivation layer, made of materials like silicon nitride, seals the LED mesa perimeter to prevent undercutting during etching and reduce moisture ingress. This allows for better reliability, reduced risk of damage, and the ability to add features like dielectric reflective layers and DBR reflectors to the chip.

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A method to improve display quality and reduce power consumption in electronic devices with displays that have pixels that can be individually controlled. The method involves determining decay rates for the pixels based on their luminance values. The luminance values for the pixels are adjusted based on their decay rates to compensate for aging and variability. This prevents image sticking, extends display life, and reduces power consumption.

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Compensating power supply voltage drop in MicroLED displays to improve brightness and color accuracy. The compensation involves detecting the voltage drop caused by current through off-chip resistors when the display is lit. This drop is compensated by adding an equal voltage to the control signal for the LEDs. The compensation can be done digitally using an algorithm or analog circuits. The algorithm involves establishing a model of the display and power supply to calculate the required compensation.

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Compensating the display junction temperature of LED digital tubes in electronic displays to prevent red shift and improve display quality. The method involves monitoring the surface temperature and current of the LEDs in the tubes. Based on the measured values, it calculates the junction temperature of the LEDs. If the junction temperature is too high, it adjusts the delay time of the display control signal to reduce switching losses and lower the junction temperature. This prevents redshift. It also extends the display control signal to avoid multiple simultaneous LED switches. This increases flux but risks afterglow. The extension time is calculated to balance these effects.

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Micro-LED display panel with redundancy to improve yield and reliability. The display has micro-LEDs arranged in sub-pixels on a driving substrate, with some sub-pixels containing two series-connected micro-LEDs of the same color. In normal sub-pixels, both LEDs emit light, but if one LED fails, only the working LED emits light. Redundancy positions allow extra LEDs to parallel connect if both originals fail. This compensates for failed LEDs and maintains full sub-pixel brightness. The redundancy prevents single LED failures from affecting display quality.

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Display panel with improved heat dissipation for micro-LEDs to avoid efficiency loss and extend lifespan. The panel has pixel units with driving circuits between the substrate and light-emitting components. For units with micro-LEDs, the circuit includes a thin-film transistor connected to a metal structure. This forms a heat dissipation path from the micro-LED to the metal layer away from the substrate.

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A micro-LED display that can sustain high brightness without overheating, which can lead to color degradation and reduced lifetime, is used. The display uses micro-caps to thermally insulate the tiny LEDs from the substrate. The micro-caps create sealed chambers around each LED that can be filled with gas or vacuum. This prevents heat buildup and protects the color conversion layers. The display also has color material layers on the micro-caps to enhance color performance.

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Display panel with improved luminous efficiency and longer device life without using lithium fluoride. The panel has a stacked inorganic packaging layer above the light-emitting device. The stack has three sublayers with refractive indices in specific order and difference. The middle sublayer has higher index than top and bottom layers. This enhances light reflection inside the microcavity to increase luminous intensity. It improves efficiency compared to two sublayer stacks. The three sublayer stack also better protects the device from water and oxygen compared to single or double stacks.

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Display panel with redundancy scheme incorporating micro-LEDs to enable high-resolution micro-LED displays with high yield and longer lifetime. The display panel includes an array of micro-LED devices in each pixel and multiple top electrodes to provide redundancy and repair capability for faulty micro-LEDs. This allows the detection and bypassing of defective micro-LEDs during panel manufacturing. The bottom electrodes are bonded to pairs of micro-LEDs that emit the same color. The top electrodes connect one micro-LED in each pair to the ground line. If a micro-LED is faulty, the other micro-LED in the pair compensates for it. The display also uses an integrated test method where imaging after transfer detects faulty micro-LEDs for replacement before passivation and top electrode formation.

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A method to prevent display brightness from decreasing below a target level as light-emitting diodes (LEDs) age. The method involves initially setting the LED output higher than the target brightness when the LEDs are turned on. This compensates for luminance loss due to aging. Subsequent brightness corrections account for both aging and initial overdrive. By starting higher, the LEDs can be replaced at the target lifetime even if they degrade faster from initial overdrive. This prevents brightness from dropping below the target.

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Dynamic power supply adjustment for microLED arrays to improve efficiency and reduce losses compared to fixed high voltage supplies. The power supply voltage is dynamically adjusted based on operating conditions like temperature and current amplitude to match the actual required voltage. This avoids excessive fixed voltage that wastes power in the current source and causes losses. The voltage adjustment is determined using data on the LED forward voltage and process spread.

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A display system with multiple displays that compensates for brightness variation between displays due to aging LEDs. The system has individual LED units for each display area. It tracks cumulative lighting time, initial brightness, and temperature for each LED. A control unit calculates estimated brightness based on this data and sets a common brightness level across the displays to balance brightness. This mitigates brightness differences between displays as LEDs age.

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Point-by-point brightness and chromaticity correction system for LED modules that compensates for temperature effects to improve display quality. The system involves adding a temperature sensor in the LED module. When the module is powered on, the temperature is read by an onboard MCU. This temperature is matched with pre-calculated correction coefficients for brightness and chromaticity at different temperatures. These coefficients are stored in the display controller and used for step-by-step correction of the LED module's pixels at different operating temperatures. This prevents temperature drift and color cast issues in LED displays.

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LED display device with brightness correction to maintain uniformity when LEDs degrade over time. The device calculates the cumulative lighting time of each LED, looks up the degradation rate from a table, and applies correction to LEDs with lower degradation. This prevents excessive brightness drop in aged LEDs while avoiding correction of severely degraded LEDs. The threshold for correction is set based on the average degradation rate. By selectively correcting based on degradation level, it preserves display uniformity as LEDs age.

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LED display device that prevents damage to the LED elements due to temperature changes when the display is turned on at high brightness without requiring a warm-up break-in procedure. The device calculates the brightness of each LED based on the video input, calculates the temperature rise for that brightness, and then controls a heater inside the display to generate the calculated temperature rise. This pre-heats the LEDs before they are turned on at high brightness, preventing moisture expansion and vaporization that can damage the LEDs.

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Optimizing the lifetime of LED displays like OLED and microLED screens by managing the luminance based on temperatures in different display areas. Sensors on the display, PCB, and adjacent components measure temperatures. A heat map is generated showing the hotspots. Luminance is adjusted for each area to compensate for higher temperatures and prevent premature aging. The heat map allows optimizing display brightness across areas with varying heat conditions.

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An LED display device with a correction method to maintain uniform brightness over time. The display has aging test sections with identical LEDs. Their brightness is measured, temperatures recorded, and accumulated usage time tracked. This data is used to calculate correction factors for each display LED based on its age and temperature. The display driver then applies these factors to correct the brightness of each LED element. This compensates for aging variations between LEDs. By using aging test sections, accurate correction factors can be calculated without stopping the display.

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Preventing damage to LED elements in displays when restarting after long periods of inactivity. The display system has a humidity sensor that monitors humidity levels when the display is powered off. This data is stored. When the display is restarted after a long off period, the stored humidity data is used to calculate a gradual brightness ramp for the LED elements. This prevents rapid heating and expansion of the sealing epoxy that can cause delamination and damage. By starting at reduced brightness and gradually ramping up, it prevents epoxy expansion and exfoliation when the display is restarted after extended off periods.

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A micro-LED display device provides high energy efficiency, wide viewing angles, and a long lifetime. The device consists of a micro-LED array, a light transmission layer, a color filter, and a polariser. An electrode layer drives the micro-LED array to emit light, which passes through the transmission layer, color filter, and polariser to create the display image.

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LED display device that improves the uniformity of brightness and color across an LED display over time as the LEDs age. The device has a separate aging LED display with identical LEDs for each color. A brightness meter measures the dimming values of the aging LEDs based on the periods of the main display LEDs. Correction factors are calculated based on the main display LED periods and aging LED dimming values. These factors are then applied to adjust the brightness of the main display LEDs for each color. This compensates for the varying dimming characteristics of individual LEDs to maintain consistent brightness and color over time as the main display LEDs age.

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Method to correct LED display screens to maintain consistent color and brightness over time and prevent temperature-induced color shifts. The method involves calculating the warm-up time for the display to stabilize after power-on, then performing aging tests at normal temperature for that time to correct the display. By simulating the temperature rise that occurs during use, the correction compensates for temperature-sensitive LED efficiency changes. This prevents color casts and brightness variations that can occur when displays heat up during long-term operation.

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Intelligent method to maintain constant brightness from LED lights to avoid premature failure and uniformity issues. The method involves calculating an adjusted current value based on sampling voltage, current, temperature, and time to compensate for degradation and variations. It uses algorithms like single point and multi point effective averaging to filter and average the sampled data over time. By dynamically adjusting the current based on degradation indicators, it aims to maintain consistent brightness over the life of the LEDs.

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Active temperature control for LED high power applications to prevent overheating and prolong lifetime. The circuit uses a temperature sensor and hysteresis comparator to monitor LED module temperature. If it rises, it reduces the LED current reference. If it falls, it raises the reference. This prevents overheating by reducing power when needed, but keeps lighting when cooler. The comparator sets thresholds based on temperature sensor readings.

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Optimizing LED light source performance and lifetime by compensating for age-related lumen depreciation during operation. The method involves monitoring temperature inside the LED light engine to determine the portion of supplied power converted to light vs heat. This is used to calculate a compensation factor that adjusts the power supplied to the LEDs to account for aging. By tracking temperature changes over time, the compensation factor can be adjusted to maintain constant light output as the LEDs degrade.

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LED chips and packages with lenses made of materials that resist degradation at higher temperatures compared to polymer lenses. The lenses are made of non-polymer materials like glass, quartz, or sapphire that can withstand elevated temperatures without discoloration or cracking. The lenses are mounted to the LED prior to critical metallization steps to avoid damaging metalized components at the high bonding temperatures. The lenses have similar coefficients of thermal expansion as the LED semiconductor to allow reliable operation through temperature cycles. The LED chips have flip-chip geometry with lenses directly mounted to the top surface, eliminating polymer materials in contact with the LED. This prevents degradation of the LED due to elevated temperatures.

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A method to prevent LED lights from fading brightness over time and maintain consistent light output throughout the life of the LED. The method involves using a control device with a processor, power modules, depreciation statistics unit, and LED driver circuit. The processor adjusts the LED output power based on decay thresholds and ambient temperature. It starts with low power and gradually increases as the LED approaches decay thresholds. The statistics unit tracks LED use time and temperature to compare against decay tables. This compensates for brightness changes due to aging and temperature effects.

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Display device design to balance performance and lifespan by managing temperature-dependent component degradation. The device estimates thermal accumulated deterioration based on past temperature behavior and compares it to total operation time. If the accumulated degradation exceeds the reference value, it limits boosting the backlight power to prevent excessive degradation and extending device life. This allows higher performance modes without premature failure when operated at lower brightness levels. The device balances between performance and lifespan by controlling power and temperature to prevent excessive degradation.

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Reducing the temperature of LED display screens to improve reliability and extend lifespan by actively monitoring and controlling the temperature of individual LED dies. Each LED module has a temperature sensor and a separate controller. The controller continuously monitors the die temperature. If the die temperature exceeds a threshold, the controller reduces the drive current to the LED to lower its temperature. This active cooling prevents excessive heat buildup in the LED dies, which can degrade performance and shorten lifespan. By individually controlling and monitoring the die temperatures, it allows targeted cooling without affecting the overall screen brightness.

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An LED display device that extends the lifetime of the LEDs while maintaining stable brightness over time. The device has a control unit with a timer and a storage to store LED brightness and lighting time data. The initial LED forward current is set to closely match the brightness at the end of life. During operation, the control unit estimates the brightness decay based on the LED's lighting time and adjusts the forward current to prevent brightness from falling below end-of-life levels. This allows extending LED life while stabilizing brightness over time.

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