Extending Service Life of Micro-LED Displays

(Summary) 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.

(Summary) An electronic device with a protective layer that prevents moisture and air intrusion and reduces the risk of delamination or damage to the light-emitting units due to thermal expansion mismatch. The protective layer has a Young's modulus less than or equal to 20 MPa. This low modulus allows the protective layer to deform and conform to the substrate and light-emitting units, preventing gaps that allow moisture and air ingress. It also reduces peeling and delamination. The low modulus also allows the protective layer to flex without cracking when pressed, preventing damage. The low modulus protective layer can be combined with wavelength conversion particles or reflective structures in the layer to simplify manufacturing and improve color saturation and efficiency.

(Summary) 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.

(Summary) 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.

(Summary) 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.

(Summary) 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.

(Summary) 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.

(Summary) 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.

(Summary) 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.