304 North Cardinal St.
Dorchester Center, MA 02124
304 North Cardinal St.
Dorchester Center, MA 02124
It felt like the CES of old this year, with many meetings and interesting booths. Everything was scrambled around with no South Hall and a new West Hall. There were about 60% of the people and booths of pre-pandemic CES, but I could not have been much busier. With the venues spread out at CES 2023 and the slightly lesser crowds, it was a bit easier to get around Vegas than in past years.
I found a lot of good technology from CES to write about and some not-so-good, plus I have many photos and videos “in the can” to finish up the series on the Meta Quest Pro. I want to get through everything before the SPIE AR/VR/MR conference at the end of January, but it will be a challenge as this blog tends to go into depth on topics rather than just giving my impressions. I don’t plan on going into as much detail on most other products, but I felt the importance of non-polarization-based dimming needed to be explained.
Brad, of SadlyIsBradley, and I plan to record some of the best things we found at CES that should start coming out next week if all goes well. Brad mostly looked at VR and MR, and I covered AR/MR, so we will each have different things to discuss and/or from different perspectives. I will let you know when the video gets posted.
I decided to start my CES 2023 coverage with Meta Materials’ electrochromic dimmer. It could greatly impact AR/MR headsets and many other applications in the near future.
Meta Materials was founded in 2007 based on metamaterials, microscopic structures manipulating electromagnetic waves from radio to visible light to infrared. In AR/VR, the news of Harvard’s work with metamaterials/lenses has made more people aware of metamaterials.
When Facebook changed its name to Meta and made a big deal out of the Metaverse, the name Meta took on a whole different meaning. It so happens that Meta Materials was working on some of the devices and technologies for devices that could be used in the Metaverse. Facebook’s renaming to Meta caused a lot of publicity and confusion with the existing Meta Materials.
While I had seen the Meta Materials booth at AWE 2022, it was not until CES 2023 did I understand what they had to offer. At AWE 2022, I was interested in their custom lens technology known as ARFusion (see Meta Materials presentation at AWE 2022), which could be a competitor to Luxexcel (recently bought by Meta=Facebook). I discussed some of the advantages of Meta Materials’ “ARFusion” lens technology over Luxexcel in my AWE video with SadleyItsBradly. In an upcoming article, I will be writing more about AddOptics, another company I met with at CES, which has a custom lens-making technology that has an advantage over Luxexcel’s (now Meta’s) 3-D printing technology.
This article will concentrate on Meta Materials’ electrochromic (electrically controlled) dimming technology. This technology combines PPG’s electrochromic gel, most famously used in the Boeing 787 electrically dimming windows, with Meta Materials’ ARFusion Lenses and metamaterials to control and enhance the response. Meta closed an agreement with PPG in May 2022.
Before diving more deeply into electrochromic dimming, it should be noted that Meta Materials made a big social media splash at CES 2023 and was #1 or #2 (to Lenovo) out of over 2,200 vendors in social media following, according to the large CES Discovery Wall based on social meta mentions collected by BuzzRadar. That is very impressive for a company few had heard about before CES 2023.
I think the product that grabbed the most attention was Meta Materials’ transparent Microwave Oven door. The door uses a metamaterial structure tuned to reflect microwaves but passes visible light waves.
This same basic technology can be used in windows as EMI shields to prevent electronic eavesdropping. With a different metamaterial film, windows can act to funnel the radio waves into the building through windows. Meta also showed putting transparent antennas in the lenses of glasses.
Another use for metamaterials is transparent heaters for outdoor cameras, car headlamps, car taillights, and stoplights. With the widespread adoption of LEDs for lighting, there is not enough heat to clear snow and ice when necessary. By, in essence, programming the metamaterial, they can tune it to different wavelengths of the electromagnetic spectrum. Meta Materials claimed advantages over the current array of thin wire and ITO-based electrodes with their conductive metamaterials that can be “tuned.”
Two common ways to control dimming in glasses are photochromic (light-controlled) and electrochromic (electrically-control).
Photochromics, most famously Transitions™, typically go dark due to the UV light on the lenses and can’t be otherwise controlled. They can be formulated to transition by different amounts and colors, but the transition is then fixed in the material. The transition times are usually slow, taking about 30 seconds to a minute to go dark and up to 2 to 3 minutes to go to their most transmissive state.
Today’s common electrochromic dimmers use liquid crystals to manipulate polarized light. They work like an LCD with a “shutter” having a single large pixel, or they can be segmented. Importantly, fast-switching liquid crystals manipulate polarized light, and for them to work, the light must first be polarized, which blocks over 50% of the incoming light. So the most transparent polarization-based electrochromic dimmers can be less than 50%.
The control of electronic dimmers could be from either an ambient light sensor or in AR/MR, based on processing camera information.
The most recent and well-known application for polarizing LC dimmers in AR/MR is the Magic Leap 2’s segmented dimming that I discussed in Magic Leap 2 (Pt. 3): Soft Edge Occlusion, a Solution for Investors and Not Users. Magic Leap 2’s most transparent state blocks 78% of the real-world light. Using an LC means they started by blocking over 60% of the real-world light, with less than 18% of the real-world light being blocked by the rest of the optics, including the waveguides.
I also discussed the complexity and problems with Magic Leap 2’s dimming technology in the AWE 2022 video I made with SadlyItsBradley.
As far as I am aware, no AR/MR company before Magic Leap built a product with a dimming layer despite the idea of using an LCD panel for dimming being decades old (and I mentioned IMMY talking about it in 2017, but I never saw a product from IMMY). Before the Magic Leap 2, nobody thought it was acceptable to block >60% of the incoming light in addition to whatever their optics block.
The big deal about the Meta Material’s dimmer is that it lets through so much more light in the transparent state. The high transparency and lack of polarization are essential for electronic dimming to be practical in AR/MR applications.
In addition to the transparency advantages, another major advantage of a non-polarizing dimmer is that it does not distort the brightness and colors of displays, such as LCDs (demo of the issue here) and automotive windshield HUDs (demo of the problem here) that output polarized light.
The pictures below show the dark state (left) and, more impressively, the transparent state (right) of the Meta Materials electrochromic dimmer prototype. The current prototype blocks about 15% in the transparent state, but Meta Materials says it will only block 2% to 4% of the light, and the slight blue going to yellow tint in the transparent state will be reduced/eliminated once it is fully developed.
Below is a short video showing the transition from light to dark and then back to light in 38 seconds. The light-to-dark transition takes about 9 seconds, and the dark-to-light about 20 seconds.
The current transition times are much slower than LCD shutters but would be acceptable for typical outdoor use with AR glasses. To use with something like Magic Leap 2’s segmented dimming, the transitions would need to be faster, or there were be “trails” left by the slowly changing/moving dimming. At a minimum, the switching speed (80/10 points) in either direction would need to be less than 1/30th of a second and preferably on the order of 1/120th of a second, the same speed as the display. Meta Materials said they know of ways to speed up the transition times, but they don’t know how fast they will get.
The Meta Materials dimmer runs on just 1V to drive to black, with the clear state being 0V. The only current that flows is when switching the static charge device, so it takes very little power.
The ability to dim the real world can be useful indoors and outdoors, but it is almost essential for general-purpose outdoor use.
Indoors in a reasonably well-lit room, a piece of white paper will typically be between 30 and 100 nits (=candellas/meter2 = cd/m2), and typical monitor outputs 100 to 250 nits. But outdoors in sunlight, green grass is about 2,500 nits, white concrete is 6,000 to 10,000 nits, and even black asphalt can be 2,200 nits.
The dynamic range outdoors, from full sunlight to shade, is huge. If the headset blocks too much light, it will have problems indoors and in the shade. What is needed is something that can quickly respond between shade and sunlight in seconds.
A person needs about 2:1 contrast for text to be easily readable and about 8:1 contrast for colors to look reasonably saturated. Even a headset with 2,000-4,000 nits will be invisible against sunlit concrete or green grass.
Automotive HUDs “win” by dominating with 15,000 or more nits. But in a headset, it would be difficult and expensive to supply and manage the power required for more than 15,000 nits. Furthermore, pumping these light levels into the eyes would be hard on them. It would be much more power efficient and easier on the eyes to darken the real world rather than blasting light over it.
I want to point out that even with ideal dimming technology, a near-eye display that can deliver less than 1000 nits to the eye will not be practical for outdoor use. There is so much dynamic range of brightness in the real world that for a sub-1000 nit image to be readable, the dimmer would have almost completely blacken out the real world, which would defeat the concept of a see-through AR/MR headset. One would like at least 3,000 nits plus the dimming capability for outdoor use.
Meta Materials says that its metamaterial enhances the performance of the PPG’s photoelectric chemicals, but I don’t know the mechanism. I also have concerns about potential diffractive effects. Meta Materials says that, unlike gratings, its metamaterials have randomness that reduces diffraction effects, plus they can tune them to reduce the effects. Of all the unknowns, the potential diffraction effects concern me the most.
Meta Materials is currently demonstrating about 15% like blockage (85%) transparent, and we will have to wait and see if they can get to 2-4% (98-96%) transparent. We will also have to wait and see how monochromatic the dimming will be throughout the range.
Hopefully, some combination of the electrochromic chemistry and the metamaterials will significantly increase the switching speed to make it workable for dynamic (soft edge occlusion) dimming. Magic Leap has demonstrated (at CES 2023) that soft edge occlusion could be very useful (if only it didn’t dim so much, to begin with).
I don’t know if some other company also has a non-polarization-based dimming technology. If they have, I have not found one before in many years of looking for it.
While AR/MR headsets need non-polarizing dimming technology, there are many other higher-volume markets for this technology, most obviously in general eyewear if the diffractive effects are low.
A nonpolarizing dimmer would be extremely useful as a secondary modulator for LEDs based displays where a large dynamic range is required. Lasers, in particular, don’t behave well at low drive levels and cut off completely rather dimming. LEDs can also be very tricky to drive at very low levels with any accuracy. Consider an automotive HUD that will be required to support over 15,000 nits for daytime use but should output less than 1 nit at night. This 15,000+ to 1 range is on top of (multiplied by) the image’s dynamic range at any give overall brightness. But when you are trying to output 15,000+ nits, you don’t want to block much light, so you need a light modulator that is highly transparent in its most transparent state.
There is also a big need in photography and video to dim incoming light variably while being as transparent as possible when needed. Camera’s ISO settings can only go so low, and stopping down the iris affects the depth of focus and causes diffraction to soften the image.
Then there are the uses to block light in windows as an alternative to shades and reduce sunlight heating in residential and automotive applications.
A non-polarizing electrochromic technology that can be highly transparent has been a critical missing technology for AR/MR that is not commonly discussed. The reason I put it as the top of the technologies I found at CES 2023 is due to its importance and because it could be seen in products soon.
As a measure of my excitement over finding Meta Materials’ electrochromic dimmer, I decided to buy some stock in Meta Materials (publicly traded) when I returned from CES 2023. Besides, if, for some reason, the dimmer runs into problems, I hope the transparent microwave door technology will be a hit😁.
Warning: This is not a recommendation but a sign of what I think is the importance of its technology. I have not done a deep analysis of the Meta Materials. If you search about Meta Materials stock, you will find that they have used financial instruments that some analysts don’t like (for example, here). I rarely buy stocks of companies I cover and have never shorted at stock.
What about worldfacing cameraes? Brad was very happy about the Sharp HMD’s front facing camera with the new ultrafast lens “TLens” from poLight.com, did you see others with that solution or did you try it your self ?
Microsoft/ US army has problems with seasickness because of bad autofocus- so guess others will go for ultrafast solutions
[…] I decided to break up the one article into multiple shorter articles. This series started with Meta Materials’ Dimming Technology in Part 1 because I saw it as having an immediate impact and a technology I had wanted for […]
Nice writeup as always. Just want to mention, un-polarized dimming can also be achieved by Liquid Crystals actually, using STN guest-host structure. Its response time might be shorter than electrochromic method, but it may have smaller tuning range of transmission.
Thanks. I seem to remember that in the early days of calculators (the mid to late 1970s), they used an LC mode that darkened without polarization, but it was very slow. The polarization-based displays were much faster. As I wrote, there may be other non-polarization-based dimming methods, but I have been looking for years and have not found them. Do you have a good pointer to a product or paper?
One related paper for your reference: https://lcd.creol.ucf.edu/Publications/2016/JSID-24-4-229.pdf
[…] series on CES 2023 is starting with foundation technologies for AR/MR rather than products with Meta Materials’ non-polarizing dimming and Porotech’s MicroLED display technologies. AddOptics 3-D printable optics molds are a […]
[…] with new foundation technologies for AR/MR rather than products. The first three parts covered Meta Materials’ non-polarizing dimming, Porotech’s MicroLED display technologies, and Addoptics 3-D Printable Optics Molds. This […]
[…] (not to be confused with Meta/Facebook) electronic dimming technology. Soon after publishing CES 2023 (Part 1) – Meta Materials’ Breakthrough Dimming Technology, I learned about FlexEnable. So to a degree, this article is an update on the Meta Materials […]