Augmented Reality (AR) has made significant strides since its inception, driven by technological advancements and innovative solutions. A critical component of AR technology is the display engine, responsible for rendering and presenting images to the user.
This blog delves into the evolution of AR display engines, the technical challenges faced, and how Focally is pioneering a new era with its Laser on Liquid Crystal on Silicon (LCOS) system, optimizing the efficiency in Augmented Reality and Virtual Reality fields.
Augmented Reality Display Engines have evolved significantly from their initial implementations in defense and consumer markets. The first notable consumer AR/VR devices appeared in the 1990s, including the Private Eye smart glasses and Nintendo’s Virtual Boy. These devices utilized scanning displays rather than flat-panel displays, setting the stage for future advancements.
However, the lack of consumer-grade IMU sensors, low-power 3D-rendering GPUs, and wireless data transfer technologies contributed to the decline of the first AR/VR boom. It wasn’t until 2012 that the AR/VR landscape began to shift, thanks to the integration of readily available smartphone display panels, pico-projector micro-display panels, IMUs, and advanced camera and depth map sensors.
Today, AR/VR Head-Mounted Display (HMD) architectures are transitioning towards more specialized technologies such as inorganic micro-LED panels, LCOS, DLP, 1D scanned arrays, and 2D laser/VCSEL MEMS scanners. These technologies are better suited to meet the immersive requirements of AR compared to traditional flat panels.
The primary task of the AR display engine is to produce the desired image, align the exit pupil with the entry pupil of the combiner (waveguides, birdbath etc), and shape the exit pupil’s aspect ratio to create the desired eyebox. The main components of a display engine include:
Illumination Engine: Critical for non-emissive display panels, providing the necessary light source.
Display Panel or Scanner: The core element that creates the image, including micro-display panels or scanning systems.
Relay Optics: These optics form the exit pupil for the combiner, ensuring the image is properly projected to the user’s eye.
Augmented Reality systems today utilize two main types of image origination systems: panel-based optical engines and scanner-based optical engines.
Direct View Panels: Typically used in smartphones, ranging from 3.5” to 5.5” in size with resolutions from 500 to 850 PPI.
Micro-Display Panels: These include emissive type such as HTPS-LCD micro-panels and reflective type silicon-backplane-based Liquid Crystal on Silicon (LCoS) panels, micro-OLED, and i-LED panels. These micro-displays range from 0.2” to 1.0” in size and offer resolutions from 2000 to 3500 PPI.
Micro-displays often require external illumination systems and have been used in various AR headsets. Polarization and emission cones are crucial features affecting brightness and perceived eyebox size. Efficiency varies among display types, with color-sequential LCoS displays being about 50% efficient, where micro-LED are about 30-40 % efficient and LTPS LCD micro-displays around 3-4% efficient.
MEMS Scanners: Implemented in various HMD systems, offering small size, high brightness, and efficiency with laser illumination. These systems can dynamically adjust the display based on gaze tracking, providing a highly immersive experience.
The illumination engine is vital for AR headsets, often accounting for a significant portion of the display engine’s volume. Polarization recycling is sometimes required for LCoS panels to achieve the desired brightness. Homogenizers like fly’s-eye arrays or lenticular arrays are essential for ensuring uniform illumination.
Once the image is formed, the display engine needs to create an exit pupil that is either collimated or partially collimated and then presented directly to the eye or through an optical combiner. Innovations in spatially de-multiplexed exit pupils and relay optics have led to more compact and efficient display engines.
As we look toward the future of AR display technologies, it is believed that three main systems will dominate: LCOS, micro-LED, and MEMS scanners. However, the consensus among experts, including insights from some of the field expert’s analysis, suggests that LCOS and micro-LED are more promising for mainstream AR applications compared to MEMS scanners, which face inherent challenges such as scan pattern visibility and visual discomfort.
MEMS (Micro-Electro-Mechanical Systems) scanners are an intriguing technology for Augmented Reality display engine due to their compact size and efficiency when paired with laser illumination. They work by using tiny mirrors to scan a laser beam across a surface, creating an image point by point. While this method has the advantage of being able to dynamically adjust to the viewer’s gaze and environment, it also has several significant drawbacks.
Image Quality : MEMS scanners can suffer from lower image quality due to the scanning process. The image can appear less stable and more prone to distortions.
Reliability Concerns: The mechanical nature of MEMS devices introduces potential reliability issues over time.
Visual Discomfort: Users can sometimes see the individual scanning lines, which can cause visual discomfort and reduce the immersive experience, making prolonged use less comfortable.
Hard to Manufacture: The precise integration of MEMS with optics makes these systems challenging to produce.
Micro-LED technology is lauded for its brightness, formfactor and low power consumption potential. Each pixel in a micro-LED display is an individual light-emitting diode, allowing for incredibly sharp images and efficient energy use. However, this technology faces several challenges.
Manufacturing Complexity: Micro-LED displays are difficult and expensive to manufacture. The process of creating and aligning millions of tiny LEDs is complex and costly.
Brightness Levels: While micro-LEDs have great potential, achieving high brightness levels suitable for outdoor use remains a significant hurdle. This limitation can impact the practicality of micro-LEDs in various AR applications.
Heat Management: As brightness levels increase, so does the heat output, necessitating advanced cooling solutions which can add to the size and cost of the device.
LCOS (Liquid Crystal on Silicon) technology, particularly when combined with laser illumination, presents a compelling alternative for AR display engines.
Superior Brightness: LCOS panels, especially with laser backlighting, can achieve much higher brightness levels compared to micro-LEDs. This makes LCOS particularly suitable for outdoor and high ambient light environments where visibility is crucial.
Cost-Effectiveness: LCOS technology is more mature and cost-effective to produce than micro-LEDs. The manufacturing processes are well-established, leading to lower production costs and greater scalability.
Mature Technology: The LCOS technology is well-understood and has been refined over years of development, leading to reliable performance and ease of integration into AR systems.
Compatibility with Lasers: The use of coherent laser light with LCOS can produce brighter and more energy-efficient images, addressing the power consumption issues prevalent in other display technologies.
Focally has taken a revolutionary approach with its Laser on LCoS (LoL) system. By utilizing LCoS, Focally has designed an advanced illumination system that balances complexity and size. Here are some key features of Focally’s innovative display engine:
Field of View (FOV): 60 Degrees – Providing an immersive AR experience with a wide visual area, enhancing user engagement.
Resolution: 4K UHD – Delivering crystal-clear images and videos for a superior visual experience.
Compact Design: Despite advanced features, the projector remains compact and portable, suitable for various settings.
Energy-Efficient Laser Technology: Utilizing laser technology for better energy efficiency compared to traditional AR devices, extending battery life for outdoor and long-duration applications.
Wide Colour Gamut: Using proprietary RGB combination it offers a broader range of colors for more vibrant and lifelike visuals.
Higher Pixels Per Degree (PPD): Using resolution enhancing techniques it increases the visual fidelity and reduces the screen-door effect for a more realistic display.
The evolution of Augmented Reality display engines has been marked by significant technological advancements and innovative solutions. As the AR industry continues to grow, the choice of display technology will be crucial in defining the user experience. MEMS scanners, while innovative, face significant challenges that limit their applicability in high-demand AR applications.
In contrast, LCOS and micro-LED technologies are poised to dominate the future of AR displays. Among these, LCOS, especially with advancements in laser illumination, stands out as a superior choice due to its high brightness, cost-effectiveness, and mature technology.
Focally’s Laser on LCoS (LoL) system represents a major leap forward, optimizing for SoC efficiency and delivering high performance in AR and VR fields. By combining lasers with a wobbling MEMS system, Focally has created a display engine that is both compact and powerful, setting a new standard in the industry. As AR continues to evolve, Focally’s innovations will play a crucial role in shaping the future of immersive experiences.
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Cheng, D., Wang, Q., Liu, Y., Hailong, C., Ni, D., Wang, X., Yao, C., Hou, Q., Hou, W., Luo, G., Wang, Y., 2021. Design and manufacture AR head-mounted displays: A review and outlook. Light: Advanced Manufacturing 2, 1–20. https://doi.org/10.37188/lam.2021.024
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
* The images shown are closer to the visual representation and the color tone may vary slightly than the images shown.
They mean the same thing: the strength of your prescription. If you're nearsighted you will have a minus (-) before your values, and if you’re or farsighted you will have a plus (+).
This is for people with astigmatism. This is when one part of the eye needs more correction than the rest. The Cylinder value is written with a minus (-) sign.
This is only for people with astigmatism. The axis is a number between 0 and 180 and determines the orientation of the Cylinder (CYL).
This mainly applies if you have Progressive or Bifocal power. This mainly specifies the near spherical power or for presbyopia. Incase you want only near power, you can fill in AP value as per your prescribed details.
If you have only one PD value above 50, then please divide that by 2 & fill in both
eyes equally. For example for 64 PD value, Fill it with 32 and 32 for Right and Left.
In case doctor has specified these separately for each eye, you can fill them separately.
You can leave the input box empty if you don’t have them in your vision correction details.
