Introduction
MicroLEDs, known for their high resolution, offer promising potential for intelligent lighting solutions. Their applications are vast and could be transformative. For instance,
According to industry experts, microLED headlight systems can save up to 30W of power consumption, 30% installation space, and 30% weight per headlamp pair compared to the incumbent digital mirror device (DMD) technology.
All these reductions are possible by using microLEDs only when required. For instance, activating only the pixels when in need will eventually minimize wastage and increase the efficiency of microLEDs.
The power of microLEDs has been observed in the recent vehicles that have been launched. For example,
Porsche invented an HD matrix headlamp technology in 2022, which consists of a single chip with over 16,000 programmable microLEDs that distributes light evenly, enabling glare-free high beams that do not dazzle oncoming drivers.
This article thoroughly examines the technical advancements that microLEDs bring to automotive lighting, analyzing the quantifiable improvements they offer, such as increased luminous efficacy (lumens per watt) and better light control.
MicroLED Technology: Patent Landscape in Automotive Headlight Systems
There has been an increase in the number of patents related to microLED technology for automotive headlights over the past few years.
As per a report by KnowMade, the annual growth rate of microLED display patent filings has exceeded 30% since 2015.
Here are some of the patents:
Patent US11738688
This patent by Magna Mirrors of America Inc., based in Holland, Michigan, United States, is titled “Vehicular lighting assembly with microLED lighting device.”
The lighting consists of a microLED lighting device with LEDs organized in a two-dimensional array, allowing each one to be controlled individually to create specific patterns of light output. This device is installed within the housing of a vehicle’s lighting system, which makes it a part of either the headlight or taillight.
With this, vibrant and adaptable lighting effects can be created that support advanced functions like high beams that avoid dazzling other drivers, the projection of images or information onto the road, and the ability to personalize lighting designs.
Additionally, the design includes optical elements, such as lenses or reflectors, to collimate and direct the light output from the microLED array onto the desired illumination area.
Patent CN203431672U
Titled “LED microlens-arrayed headlamp for automotive lighting,” this patent describes a microLED headlamp that uses a collimator and free-form micro-lens array without the need for light barriers.
- The headlamp consists of an array of micro-lenses in combination with LED light sources to provide automotive lighting. The LED chips are mounted on an aluminum base, which is then attached to a heat sink/radiator.
- A collimator is positioned in front of the LED chips to convert the divergent light into a collimated beam. This collimated light then passes through a free-form curved surface micro-lens array. The micro-lens array helps control the light distribution and shape the beam pattern without the need for additional light-blocking elements.
- This optical design allows the headlamp to meet standard light distribution requirements for vehicle headlights while improving the overall efficiency of the system. The micro-lens array enables precise control over the light output, enabling features like glare-free high beams and customizable lighting signatures.
Japanese Patent JP2009211963
This patent, describes a conventional vehicle headlight using variable shades to vary the light distribution pattern. While not directly related to microLEDs, it provides context on the evolution of headlight technology.
This patent describes a conventional vehicle headlight that uses variable shades to vary the light distribution pattern. Specifically, it covers a headlight assembly that includes:
- A light source, such as a halogen or discharge lamp, to generate the initial light.
- A shade mechanism is positioned in front of the light source. This shade can move to adjust its position relative to the light source.
- By controlling the position of the shade, the light distribution pattern projected onto the road can be dynamically modified.
This allows the headlight to adapt the beam shape and intensity based on driving conditions, such as switching between high and low beams.
Key Players in Reshaping MicroLED Automotive Headlight Technology
In this space, a number of significant companies have surfaced, each boasting a considerable collection of patents. Some of these are:
Lumens Co., Ltd.
Lumens’ patent applications cover innovative microLED chip designs and architectures to enable high-resolution, high-efficiency, and adaptive lighting capabilities. This includes:
- Novel microLED structures with reduced defects and improved light output
- Techniques for miniaturizing LED chips from millimeters to microns in size
- Arrangements of microLED elements in high-density two-dimensional arrays
Nichia Corporation
Nichia has patented novel microLED chip designs and architectures to improve performance and efficiency. This includes innovations in the epitaxial growth of microLED structures, such as the use of quantum wells and nanowires to enhance light output and color quality.
The company has also developed techniques to miniaturize the LED chips down to the micron scale while maintaining high reliability and uniformity.
Epistar Corporation
Epistar’s patents cover microLED epitaxial growth, chip design, and packaging technologies.
MicroLED Epitaxial Growth
Epistar has developed patented processes for growing microLED structures on 6-inch sapphire wafers for blue and green LEDs and 6-inch GaAs wafers for red LEDs.
The company has also filed patents on using 8-inch GaN-on-Silicon wafers for monolithic microLED devices that need to be bonded to CMOS backplanes.
Innovative epitaxial growth techniques are used to improve efficiency, and uniformity, and reduce defects in the microLED structures.
MicroLED Chip Design
Epistar’s patents cover novel microLED chip architectures to enhance performance and manufacturability at the micro-scale.
This includes techniques to minimize the well-known “efficiency droop” issue, where LED efficiency drops at higher current densities.
The company has also patented designs to improve the quality and yield of microLED chips, which is critical for large-scale displays.
MicroLED Packaging and Transfer
Epistar has developed packaging formats like “Chip on Tape” (COT) and “Chip on Glass” (COG) to enable efficient handling and transfer of microLED dies.
The company has filed patents on mass transfer techniques, including laser-based, stamp-based, and self-alignment methods, to place the microLED dies onto backplanes and display substrates.
Specialized bonding and interconnect technologies are used to integrate the microLEDs with the driving circuitry while maintaining high reliability.
Final Remark
MicroLED technology is set to revolutionize automotive headlights, offering significant advancements in energy efficiency, space savings, and weight reduction.
Future developments should focus on enhancing the integration of microLED systems into various vehicle models, further optimizing light control, and improving manufacturing processes to reduce costs. Automakers should continue to collaborate with microLED manufacturers to explore innovative designs that maximize performance and adaptability.
As patent filings indicate growing interest and investment, it is clear that microLED technology will play a crucial role in the future of automotive lighting, promising safer, more efficient, and versatile lighting solutions.