Micro-LED Quality Validation

Contactless micro LED inspection system that uses pulsed lasers to detect defective micro LEDs without direct electrical testing. The system emits pulsed lasers at the LEDs to generate photovoltaic radio frequency signals when radiated. An antenna receives these signals, which are amplified and analyzed by a processor to determine if the LED is functioning or defective. This allows high-efficiency, contactless testing of micro LED arrays without needing to electrically test each individual tiny LED.

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Contactless and high efficiency method for inspecting micro LEDs using radio frequency (RF) induction and imaging. The method involves applying an RF signal to a glass panel with a conductive layer on top of the micro LEDs. The RF illuminates the LEDs by induction through the conductive layer. A camera captures images of the RF-illuminated LEDs. Analysis of the images determines if the LEDs are defective or functioning. The RF-induction allows contactless testing of micro LEDs without direct electrical contacts that can damage the tiny chips.

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Imaging device for fast and stable testing of display screens to measure spectrum, brightness, chromaticity, and viewing angle optical characteristics on a single device. The analyzer has a turntable with a CCD electronic lens and conoscope lens mounted off-center. A rangefinder is at the center. A spectrometer, RGB camera, and filter switch are inside. The turntable rotates to image displays from different angles. The lens offset and through hole align with the turntable axis for consistent imaging. This allows simultaneous spectroscopy, colorimetry, and angular analysis of displays.

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Objective and precise method to measure the color depth of display devices using specialized equipment like signal generators, optical measurement devices, and data analysis tools. The method involves connecting the display device under test to a signal generator, measuring the brightness and grayscale response using optical equipment, and analyzing the data to calculate the color depth. This provides a more accurate and objective method compared to subjective evaluation or calibration tools that indirectly affect color depth.

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Display screen brightness and chromaticity measurement system that can quickly and accurately measure uniformity of a display screen without the limitations of point-by-point scanning or imaging array instruments. The system uses moveable area array cameras mounted on rails to scan and measure multiple sub-areas of the screen. Spectrometers connected to the cameras capture spectral data. This allows simultaneous, efficient measurement of brightness and chromaticity across the screen without vignetting or viewing angle issues. The cameras can move along rails to scan sub-areas, providing comprehensive coverage without manual scanning.

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Rapidly verifying many micro-LEDs quickly identifies and removes defective chips. The method uses a wafer-level verification technique, creating an LED verification substrate with contact bumps connecting to the LED chips. The verification substrate containing multiple verification chips is bonded to the LED wafer. Power is applied to the contacts to turn on the LED chips. Any chips that don't emit light are identified as defective and removed.

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Method for accurately measuring display characteristics like luminance, color, and spectral distribution of activated displays that have performance variations during and between measurements. The method involves configuring the measurement setup to perform each optical measurement as a sequence of identical measurements, like pairs of 2D images or spot measurements. Time-averaging the results from each sequence improves accuracy compared to single measurements. This compensates for the display's changing performance during measurements.

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An apparatus for inspecting illumination of micro LEDs that addresses the need to efficiently screen and inspect completed micro LEDs before transferring them from a wafer to a target substrate. The apparatus uses a surface-contact probe that touches the front surface of the micro LED assembly and supplies power to the LED ends to turn them on. An imaging unit photographs the LED assembly before and after power is supplied to inspect the overall illumination.

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Objectively quantifying and evaluating pixel saturation of LED displays to optimize image quality and reduce moire artifacts when capturing images of LED screens. The method involves calculating the pixel filling rate by dividing the display into equal blocks, counting pixels with brightness above a threshold, and comparing to the total. A higher filling rate reduces moire but excessively saturated displays lose sharpness. This provides an objective metric to determine optimal pixel saturation for LED displays.

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An apparatus for inspecting the illumination quality of micro LEDs. It uses a surface-contact probe to turn on the micro LEDs and interconnect them, then photographs the lit LED array to inspect their illumination.

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Calibrating LED display screens with mixed modules from different batches to eliminate brightness and chromaticity variations between batches without full rescreen calibration. After initial calibration, measure the corrected brightness and chromaticity of each module. Use these values to determine a common target for secondary calibration. Then, apply the target to uniformly correct the entire screen. This avoids assembly and site calibration for mixed screens by leveraging the initial calibration data.

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Donor substrates and conductive architectures for on-wafer testing of micro LED display panels. The architectures aim to allow testing of the micro LEDs before transfer to identify good devices. They involve conductive stabilization structures to support and electrically connect the LEDs on the donor substrate. This enables testing of the micro LEDs while still on the donor substrate and prior to transfer to the final display substrate.

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Micro LED display module manufacturing method that improves yield by allowing replacement of defective LEDs before final assembly. The method involves pressurizing the LEDs on the substrate before curing the adhesive layer, to electrically connect them and check their operation. Defective LEDs are identified and replaced with alternatives.

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A method of producing microLED displays that allows efficient and accurate mass transfer of microLED chips onto a display substrate. It involves probing and measuring the chips to create a database of chip characteristics. The chips are then transferred en masse using an expanded tape to match bonding pad spacing. This avoids individual pick-and-place and sorting steps.

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LED display unit yin and yang color measurement device and method that enables accurate and automated measurement of color non-uniformity in LED displays without manual participation. The method involves using light collectors on opposite sides of the display to capture light emitted by the LEDs. By comparing the signals from the collectors, the brightness difference between areas of the display can be determined to identify yin and yang color issues. This provides a quick and efficient way to assess and improve display uniformity without manual intervention.

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A display screen chromaticity and brightness testing device for efficiently and accurately measuring the color accuracy and brightness of display screens. It uses a control box with multiple test stations arranged on the top cover. Each test station has a light source, color filters, and sensors to simulate specific display conditions and measure the screen's response. This allows automated, repeatable testing of multiple displays without manual intervention. The control box coordinates the testing and collects the data for analysis.

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A method for calibrating LED display screens that reduces cost and complexity compared to traditional methods. The method involves using the display itself to calibrate rather than external equipment. The display panel has an optical collection array to measure light from individual LEDs. The control module calculates target adjustment values for each LED based on measured brightness decay. These values are sent to the LED array through the drive module to correct color cast. The display can then self-calibrate over time as needed.

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Chromaticity measurement method and device for calibrating LED tiled displays with high accuracy and convenience. The method involves using a combination of imaging sensors and spectrometers to measure color and spectrum at multiple regions of an LED tiled display. It utilizes partially transparent and partially reflective mirrors to separate outgoing light and direct a portion to the imaging sensor for color analysis and another portion to a spectrometer for spectral measurement. This allows accurate chromaticity calibration of the display by leveraging the spectrometer data to correct the imaging sensor measurements. The removable spectrometer design enables easy measurement of different display regions.

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Pick and place apparatus for testing LEDs during production that allows faster and more compact LED testing compared to traditional methods. The apparatus uses a bond head with a translucent portion that allows light from the LEDs to pass through to an optical sensor. This allows the LEDs to be optically tested while they are being picked and placed for electrical testing. The optical characteristics are used to sort the LEDs into bins with similar optical properties. This enables more uniform displays by bonding LEDs from different bins with matching optical characteristics.

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Automated method to test display brightness, contrast, and color temperature using a built-in display mode to reduce external signal interference. The method involves connecting a display under test, a scanner, a color analyzer, and a computer. The computer sends test patterns to the display, scans the display with the scanner, and measures color using the analyzer. It calculates average and minimum brightness values from multiple points to determine display brightness.

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