Visual China.
Text |AR Star Man, Author |Li Peilin.When Cook shouted spatial computing at the Apple Vision Pro launch conference in 2023, few people knew that as early as 2021, Xu Chi, the founder of Xreal, proposed the "spatial Internet".
According to Geek Park's interview with Xu Chi in 2021, Meta proposed the concept of the metaverse at that time and Xu Chi was quite uninterested after the fire, and he preferred to use the spatial Internet to express a similar concept: the mobile Internet uses a 2D screen frame to browse the digital world, and the spatial Internet uses AR devices to break through the limitations of the frame to enter the digital world. It doesn't matter if you call it Fang Universe. 」
Yesterday, Xreal officially announced the news of 60 million US dollars in financing, and I deeply felt how difficult it is for this kind of hardware entrepreneur who can't see the future (money). If there are a certain number of shipments in the consumer market in the next 5 years, Xu Chi is the Musk in the AR circle, the legend chews broken glass while staring at the abyss, and finally survives the turnaround. If there is no improvement after this sum of money is spent, it may be Jia Yueting in the AR circle, and the ending may be like the collapse of Yingchuang or even the founder is imprisoned.
As early as 2021, Xu Chi said: "Entrepreneurship in the hardware industry is dancing with shackles, on the one hand, we must pay attention to the process of the hardware industry chain, and on the other hand, we must be able to imagine the future of the track, and the sense of rhythm is very important." ”
Perhaps the implication of this sentence is that once you don't step on the right rhythm, you will most likely become a "martyr".
Xreal brings Birdbath's consumer-grade AR glasses with a fold-back optical path to the industry. Birdbath originally means "bird's pot", and this AR glasses got its name from the curved mirror that designed the light path to pass through and resembled a "bird's pot".
XREAL's Birdbath glasses, with their excellent industrial design and a near-fashionable appearance, do not look weird and obtrusive for everyday use, and are lightweight enough to fold in your pocket, and the display effect will impress first-time adopters. XREAL's Birdbath glasses, compared with OST AR glasses that also have spatial display functions, such as Dream Glass with off-axis optics and Mirage launched by Lenovo, the relatively bulky "helmet" all-in-one machine, Birdbath is obviously easier to open the consumer market.
But at this stage, strictly speaking, Birdbath glasses are only a single-function glasses screen projector, which needs to be connected to external mobile phones, PSP game consoles, PCs and other computing terminals, and the display principle belongs to the OST of partial light transmission, which is barely considered AR, but the interactive function is extremely weak. In the imagination, birdbath uses it to virtualize a "big screen" from the space for work or entertainment, and audiophiles use high-frequency scenarios to generate a "big screen" to watch movies or play games privately while lying down, which is a lazy artifact.
Before returning to China at the end of 2016 to start his own business, Xu Chi, the founder of Xreal, was hired by Magic Leap to be responsible for the implementation and embedded optimization of the head tracking and positioning algorithm, and also worked for NVIDIA to participate in the development of the latest generation of GPU computing platforms. In 2016, it would be the irrational boom bubble period of VR AR, and Magic Leap, where Xu Chi worked, was the highest-funded and most mysterious start-up in Silicon Valley in the industry at that time, and Xu Chi, who was determined to return to China to start his own business to make AR glasses, stepped on the time point of the industry trough period from 2017 to 2020.
At the 2020 CES show in the United States, the booth of Nreal (called Nreal before Xreal was renamed) was lively, which made Xu Chi realize that the demand for consumer-grade AR glasses is real"On the track of AR, Chinese companies can be players instead of spectators, because they are close to the industrial chain and users, and the iteration speed of Chinese companies is much faster than that of their American counterparts, which has the opportunity for us to lead the United States in some directions of AR and become rule-makers. Phones are here to stay, but by 2030, 1 billion AR glasses will be on consumers' heads. "
This sentence is obviously a bit arrogant now.
How to make consumer-grade real AR glasses, in fact, no one knows.
Apple trains its sales staff not to mention the word VR, but to use spatial computing, which should match AR rather than emphasize immersive VR headsets. Vision Pro is also not like other VR manufacturers that will announce FOVs, optical lens modules and other configurations at the time of product release. Apple's move is very "Apple", it doesn't want consumers to preconceive that Vision Pro and Meta's Quest and Byte's PICO belong to the "same kind", it uses the art of language and marketing, as well as the magical experience of the product, to weaken the opinions and biases that have been formed in consumers' heads.
Vision Pro is precise, complex, ultra-high configuration, with original Eyesight and human-computer interaction with greatly upgraded software and hardware, Apple's research on VR is difficult and accumulated, and the originality of the entire program is not comparable to other manufacturers at this stage. But at the end of the day, it's essentially a VR headset with VST.
VST uses camera perspective, from the camera sensor to capture the picture, the data stream is processed, and then presented to the screen, compared to the human retina to receive photons through the optic nerve to the brain for processing and "imaging", the natural OST process, VST image delay compression to the limit is not comparable to the human eye direct vision. For example, when you use your mobile phone to open the camera shooting interface, you can clearly see the picture delay, dragging, and visible delay with a quick flick.
Unsolvable VST image delay means motion sickness, and users simply can't wear it for long periods of time in the envisioned everyday scene. When the user is wearing VR and is staring at the screen, as long as the head is turned, or the whole person is in a state of motion (such as in a speeding car, high-speed train, airplane), the inner ear detects "rotation", which will stimulate the vestibular nerve to direct the coordinated movement of the eyeball, which is the movement vision mechanism of the human brain. Relying on the camera VST will inevitably cause image delay, jitter, and the movement of the picture seen by the eyes and the movement detected by the inner ear are not synchronized, and dizziness and discomfort will occur, and this symptom varies from person to person, and some people can gradually adapt to it and others are difficult to overcome.
Motion sickness from VST is just one aspect. The picture distortion correction, color, and chiaroscuro contrast of the camera video cannot be 100% restored, and the real-world reflection glare and overexposure problems are extremely prominent on the camera, and once the headset is powered off or the system crashes, it is impossible to see the outside world, and the ongoing work or entertainment will immediately encounter safety problems.
VST Despite all these problems, Apple chose VST to implement the "spatial computing" that AR stands for. Because AR orthodox optical perspective OST is too difficult, the existing technology is simply immature.
Taking Xreal as an example, many technical details of the Birdbath module it represents are not expanded, only one of the light efficiency, the blue line represents the light from the OLED micro display, through 1-8 various optical devices, the green line represents the real world light, through the ABCDEGF "layers", what is their final light efficiency?
The schematic diagram is from Karl's personal blog KGON Tech 2021 article
Only 14% of the light from the screen of the birdbath module enters the human eye, and only 23% of the light from the external real world can pass through.
Consumer-grade AR glasses represented by Xreal, in recent years, have only made efforts to make a dojo in a snail shell, just to improve the light efficiency by a few percent, and to improve the optical design to make the picture more "clean", and the Birdbath module strives to increase the FOV (field of view) of the glasses, which will inevitably lead to bloated, which is fundamentally contradictory to the need for thinner Birdbath modules. Another technical route optical waveguide shows that the glasses are thinner and thinner, and the light transmittance of the real world is higher, but whether it is an array optical waveguide or a diffractive optical waveguide, the overall light efficiency is only about 1%-10%, and there are serious problems such as color reproduction and too small FOV.
A little further back, off-axis optics, as shown in the image below, are equipped with a screen diagonally above the glasses, and the screen image is reflected into the human eye through the free-form lens. Due to the optical characteristics, it is difficult to miniaturize the volume of off-axis optics, and the helmet-mounted design is unavoidable. The off-axis optical display effect has no obvious advantage over the birdbath, but the volume is so large, the advantage is only that the FOV (field of view) is increased from 50 ° to 90 ° compared with the birdbath, as shown in the chart
On the left is the optical principle of the off-axis optical AR headset, and on the right is the optical principle of the Birdbath glasses
The picture shows the Dream Glass AR headset with off-axis optics.
Regarding the picture display quality of several AR glasses, Karl, a well-known foreign optical expert, said that AR glasses should improve the natural display effect of virtual and real picture fusion, and rely heavily on foreign panel giants such as Sony, Samsung, LG, and domestic micro display technology progress such as Shiya and BOE. Silicon-based OLED micro display needs to improve yield, reduce cost, and increase the resolution from 1080p, 2K, 4K and even 8K, and the screen brightness will continue to improve. Theoretically, the most ideal micro LED micro display, the brightness can already achieve millions of nits, but it is still unable to achieve the most basic RGB tricolor source pixel integration of a display, and the actual commercial cost and mass production problems are still ranked behind.
Having said all this, this is still the most basic display problem of AR glasses, how to integrate the more important sensing, computing, and human-computer interaction hardware units of AR into a pair of glasses of normal volume? How to solve the problems of computing power, battery life and heating? Microsoft Hololens and Magic Leap have given their own answers, which can only be made in helmet form at this stage.
How is it possible for the consumer market to accept high-frequency AR glasses for daily use, a one-pound helmet is worn on the head every day, and it is only used in specific industrial-grade scenarios. That's why Xreal chose Birdbath, a split AR glasses:AR can only be used in the form of normal glasses without computing and storage units for the consumer market.
Compared with foreign technology giants, Chinese manufacturers do not have the ability to innovate underlying technology with underlying chips, various types of sensors, SLAM at the software and algorithm level, eye tracking, and bare hand gesture recognition.
A little judgment: Apple first makes a VR headset with camera perspective VST, and does not do a pure AR headset with optical perspective OST, because of the basic virtual and real picture superposition, the effect of OST's existing scheme is still in the primitive stage, and it is necessary to wait for further development of technology. At the very least, VR headsets have opened up the consumer-level gaming market.
Starting from 2020, not counting those manufacturers that have gone out of business or adopted non-mainstream solutions, cutting-edge startups Xreal, Rokid, Thunderbird Innovation, Shadow, consumer electronics brands Huawei, Honor, Meizu, and OPPO have entered the game one after another.
The long-awaited VISION Pro debut was sold like crazy, and Apple optimized the commonplace VST to the extreme, but it didn't dare to go into the big pit of optical OST AR. Some time ago, the circle of friends saw that it is said that Huawei has also followed up with Vision Pro, mobilized resources to engage in big projects, and it seems that it does not dare not follow the new track and new trend of consumer electronics. And Byte PICO, Google, and Meta, which have frequent layoffs, seem to have been injected with a shot in the arm and must continue to invest. The track chosen by the giants is consistent and rational.
Entrepreneurship is the game of the brave. In the long run, do the hard but right thing, or live in the moment and do the right thing? The soul of the market is tortured, who can have the last laugh.
For the time being, I would like to give my most sincere blessings to the brave!