autostereoscopic display screens supplier

In addition, the next generation of 3D technology with improved features is already in the development pipeline. 3D Global products are state-of-the-art autostereoscopic 3D displays that provide a unique, direct experience of true 3D viewing or mixed 2D/3D viewing without glasses or other devices.

SeeFront licenses the SeeFront 3D Technology to other companies. If you think your company or research institute needs to get to know SeeFront, please contact us. As SeeFront focuses on licensing to B2B customers we are unable to sell 3D displays to individuals. However, a big thank you to all 3D enthusiasts for their support of this exciting visual technology!

SeeFront 3D displays are designed to deliver high-quality stereo images to a single user. This being said, a second person can also get a decent 3D impression over the user"s shoulder or sitting next to him/her. However, the built-in eye-tracking system that ensures freedom of movement in front of the display will adjust the image when the (main) viewer moves. A secondary viewer will need to adjust his/her position accordingly in order to see an unblurred 3D image.

SeeFront 3D Technology works with any TFT panel regardless of dot pitch, including mobile phones, tablets and other handheld devices as well as notebooks and displays up to 30”

3D data have been collected and 3D models have been constructed for several years in a wide range of applications. Medical science, pharmaceutical research, automotive engineering, CAD/CAE, architecture, scientific data on climate and geography or computer games are only a few examples. However, the means of displaying the third dimension have been very limited. You either had to use special 3D eyewear (which is quite bothersome, especially if you have to wear glasses anyway) or rely on the power of your imagination to add depth to flat images. An autostereoscopic display shows 3D content as it is meant to be seen without special glasses. And while this is useful in the professional field, it also adds greatly to the fun of games and movies.

The resolution of a SeeFront 3D display depends on the TFT panel used. The higher the resolution of the chosen TFT panel is, the higher the resolution of the SeeFront 3D display will be. Thus SeeFront 3D technology technically allows for unlimited resolution.

The SeeFront 3D Technology can basically be used with any TFT display and for any sort of 3D content. However, most people want to watch TV together with their family or friends, lounging on the sofa or in their favorite armchair – and SeeFront 3D is geared towards single-user applications. While it is technically possible to use SeeFront 3D Technology for a TV application, we have not had any customer requests for this due to the reasoning above.

A SeeFront 3D display can show any kind of genuine 3D content. This means that in order to appear three-dimensional on a SeeFront 3D display an image needs to have two perspectives of the same scene, one for the left and one for the right eye. 3D images can be still or moving, natural or synthetic, produced on the fly in real time or taken from storage media. SeeFront 3D works with image and video content in most common file formats.

SeeFront 3D Technology allows for the design of single-user 3D displays of various sizes. SeeFront 3D display technology can be used for mobile phones and tablet computers as well as for laptops or TFT displays up to 32” and more.

Using the latest generation of auto-stereoscopic (or ‘lenticular’) LCD technology, Magnetic Enabl3D screens allow incredible resolution and outstanding 3D large format displays without the need for any special 3D glasses, 3D eyewear, 3D headgear or 3D projectors.

Providing the ultimate in eye-catching, crowd-stopping 3D displays, with 3D media and 3D digital signage; 3D video images and content appear to fly out of the screen and float in mid air!

•Glasses-free 3D screen technology•Auto-stereoscopic, Full-HD 1080p LCD screens•9-point multi-viewing 3D zones•176° ultra-wide viewing angle•50,000 hours viewing time•Durable and discreet design and build•IRFM technology helps prevent ‘screen burn’•Configurable Inputs/Outputs•Active ambient light sensor for energy saving control

Using the latest generation of auto-stereoscopic (or ‘lenticular’) LCD technology, Magnetic Enabl3D screens allow incredible resolution and outstanding 3D large format displays without the need for any special glasses, eyewear, headgear or projectors.

Providing the ultimate in eye-catching, crowd-stopping displays, media and digital signage; video images and content appear to fly out of the screen and float in mid air!

•Glasses-free 3D screen technology•Auto-stereoscopic, Full-HD 1080p LCD screens•9-point multi-viewing 3D zones•176° ultra-wide viewing angle•50,000 hours viewing time•Durable and discreet design and build•IRFM technology helps prevent ‘screen burn’•Configurable Inputs/Outputs•Active ambient light sensor for energy saving control

Autostereoscopy is a method of displaying stereoscopic images without the use of special headgear or glasses on the part of the viewer. These "glasses-free 3D" screens are perfect to add another level of excitement to any marketing campaign and artistic experience.

Our 3D display solutions provide captivating off-screen "POP" and the immersive perception of depth without the need for special eyewear, and the ability to play also high-definition 2D video content.Besides 3D displays, we offer state-of-the-art 3D content player and 2D-to-3D content conversion technology.

Magnetic 3D is a U.S. based company that produces autostereoscopic displays and glasses-free 3-D content. Headquartered in New York City, the company was founded in 2006 by Tom Zerega. Their proprietary Enabl3D™ technology allows them to create glasses-free 3-D images on high-definition displays and even 4K. "The TV is wearing the glasses for you," Zerega explains. From tablets to video walls, Magnetic 3D produces screens of every size and apps to work with a variety of software. In addition to the ability to convert and screen 3-D content in real time, the team produces autostereo videos and stills for their displays. Applications include marketing and advertising, digital signage, education, medical, military, trade shows, event marketing, interactive media, gaming applications and more. Magnetic has built a business around high-quality optics, software, and content starting with retail and experiential marketing, trade shows, and digital signage.

When asked about the use of screens at tradeshows, Zerega says, "Magnetic 3D"s technology is contagious so whenever it"s out there and people see it, it tends to lead to another opportunity. In general, we"ve found that when our clients use the 3-D displays in their trade show booth they get more leads than they normally would without the 3-D display. People immediately stop and stare, allowing the salesperson the opportunityto step forward and engage them in a conversation which otherwise might be difficult or awkward to do. "It"s really a great icebreaker or a stop sign for your booth."

Zerega, Founder and CEO of Magnetic 3D, got his start in professional audio/visual work setting up technology for events and concerts. In the early 2000s he became aware of the burgeoning (2-D) digital signage industry and founded Magnetic Media. An early break came in the form of a contract with the Mall of America and 17 malls in the Northeast through Pyramid Management Companies. These early displays installed in the malls were low-resolution by today"s standards at barely 720p. In spite of this success, the competition in the new market was fierce. In 2005, while looking for a way to differentiate themselves, Tom came across a company called X3D. X3D used a parallaxbarrier filter over LCD or plasma screen TVs that created an impressive 3-D effect. Magnetic Media began installing these screens in nightclubs and bars across the country, mainly in New York and L.A. as part of an early advertiser network.

By the end of 2006, the technolo­gy for lenticular TV screens was becoming available. Instead of a fil­ter blocking out what a viewer"s left and right eye see, lenticular lenses bend the light to direct the images to the appropriate eye using the cur­vature of the lens. Unlike with paral­lax barriers, the lens does not reduce the amount of light or change the color. Realizing that this technology represented the future Zerega and his partners made the decision to sell off everything they were doing in the 2-D market and become a manufac­turer of lenticular-based glasses-free 3-D displays. Magnetic Media has since updated their name to Magnet­ic 3D and has produced glasses-free 3-D displays in a range of sizes for the past decade.

In 2010, Magnetic worked with Microsoft, the Miami Dolphins and Cisco for a project called "Suites of the Future" for SuperBowl XLIV. Magnetic installed their "free-D" screens in 32 suites throughout the Miami Dolphins Stadium where NFL team owners watched the game. Each suite had team-specific content and, while the game was not shown autostereoscopically at the time, Zerega believes with a little magic it could be pulled off today. "As long as we had the right camera angles and conversion technology an autostereo game delivered in real­time would be possible. "Instead, content switched back-and-forth between Cisco Stadium-Vision, the game in real-time 2-D while commercial breaks featured 3-D info­graphics similar to what the crowd traditionally sees on the Jumbotron.

Today, Magnetic 3D is launching an exciting new business within the Company called "Magnetic Networks", a business that is similar to where it all began in the digital signage market many years ago. "We have been waiting for almost a decade to bring back the concept of 3-D Digital Out of Home advertising and we can say for sure the technology has evolved to a point where it is truly ready for prime time as a next gen marketing platform for brands. Not only has technology has matured and become better and more cost effective at the same time thanks to 4K displays, but the infrastructure and sponsor support is now there creating the perfect storm for the deployment of glasses-free 3-D signage en masse."

The idea behind Magnetic Net­works is a futuristic, immersive and glasses-free 3-D media platform. "We think of it as the advertisers answer to what"s happening in virtual reality and augmented reality for con­sumers," Zerega says. "Out-of-home advertisers are desperately vying for new way to capture your attention amongst the clutter outside the home with bigger and brighter signs but there is a theoretical limit. To have an immersive experience like VR that does not require a headset and functions as a 2-D or 3-D display seamlessly is the future that we are betting on and presently launching in NYC."

Magnetic 3D has recently installed some of their glasses-free monitors at the New York Waterway terminals at West 39th Street, Pier 79, 459 12th Avenue, as well as at the Port Imperi­al ferry terminal in Weehawken, New Jersey. They are part of a mobile phone charging station sponsored by T-Mobile. Magnetic 3D"s content sits on a computer in what is called "store and forward" format. The schedule is forwarded to the computer within the display and because the content is already stored locally the display is told to play this content at a particular time. The 3-D network that is installed at the two ferry terminals runs in a five minute loop. A commuter"s average wait-­time is about ten minutes so the loop repeats twice. There are up to ten 30-second time slots available.

Zerega further explains, "There are also 2-D screens on the boats and in the terminals, so it"s a combination of 2-D content and 3-D content on our charging stations. The stations can charge up to sixteen devices. People can just walk over and plug in and then hang out, watch the content for five or 10 minutes and then grab their phone and jump on the ferry."

Much of the content Magnetic 3D produces for advertisers is CGI. They use After Effects, 3ds Max and Maya and have their own plug-ins that allow them to take content produced in those programs and output them into the multiple views needed to produce autostereoscopic images.

Beyond Magnetic Networks and that advertising play, Zerega would like to see the company"s screens in the classroom. "I"m really a proponent for using this technology in an educational setting. My parents and my sister are teachers. They have access to some technologies that they can use, but the kids are just so quick nowadays with the latest gadget in their pocket. Everybody"s got a smartphone or a tablet. I really believe you need to stay ahead of them to capture their attention and based on the reaction we see from people everyday, we feel like our technology could be the bridge that kids need to become re-engaged and focused on their education. So much of our world can be explained so much faster and easier in 3-D, from biology to math. It seems a shame to use the attention grabbing capability of our displays only for selling products when they could do so much more in education."

Devices displaying stereoscopic images without the use of special headgear or glasses on the part of the viewer.Learn more in: Interacting with Augmented Reality Mirrors

A display which produces an effect of depth for the viewer without any glasses.Learn more in: Improved Interaction for Mid-Air Projection Screen Technology

This page is for aggregating the latest know-how and links to current Stereo 3D display options best suited for molecular graphics applications like PyMOL. Please strive to provide objective factual information based on first-hand experiences while using the displays for real work and teaching.

Windows Start Button > Control Panel > NVidia Control Panel > Manage 3D Settings (tab) > Global Settings (tab on the right) > Base Profile (tab). Then, under Settings choose Stereo - Display Mode. Next, select Generic Active Stereo (with NVidia IR Emitter). If you have a DLP monitor/TV choose the corresponding DLP option. You must also set Stereo - Enable to on.

Projection televisions tend to be too large and fuzzy for desktop use. Also, a band of about 20 pixels around on the edge of the display are invisible, and this limitation cannot be eliminated through overscan since the image must be scanned at native resolution in order to support stereo 3D. The workaround is to shrink the PyMOL window to cover the visible portion of the screen. It is worth noting that true 3D-capable LCDs (as distinct from 3D-capable HDTVs) do not suffer from this problem.

iZ3D, the original supplier of Zalman display drivers has ceased operation and support as of 31 July 2012. DO NOT PURCHASE THESE MONITORS WITHOUT FURTHER CONFIRMATION of display support, the iZ3D support (required drivers, etc) is not activatable. If you do have further information, please post it here. Jedgold 12:21, 12 September 2012 (CDT)

Zalman 22-inch 3D LCD monitor - works with PyMOL 1.2b3 & later without any special drivers. Great stereo quality provided that all drawn lines are at least 2 pixels thick. Menus are a bit awkward to use while in stereo mode, but even so, this 650 USD display provides excellent 3D molecular visualization in both full-screen in windowed modes. - WLD (The Zalman ZM-M220W is DeLano Scientific"s RECOMMENDED SOLUTION as of Feb 11, 2009!).

IZ3D - works with PyMOL 1.2b3 & later without any special drivers. However, this display exhibits far too much cross-talk and interference between the two stereo images. Not suitable for professional use. - WLD

Planar3D "I have used these displays with nVidia Quadro graphics cards under both Windows and Linux running both PyMOL and Maestro. They work well, and the stereo quality is excellent!" - WLD.

Although these displays require shutter glasses out of the box, when combined with the adapters below and a special "silvered" screen, they can be used to project Passive Stereo 3D to a large audience.

Christie MIRAGE S+4K SXGA+ 6500 LUMEN DLP™ STEREOSCOPIC PROJECTOR "I have been very impressed with the stereo 3D effect produced by MIRAGE projectors equipped with StereoGraphic ZScreens running PyMOL under Windows with a high-end nVidia Quadro card." - WLD.

When we go to the cinema to see 3D movies, we usually wear special 3D glasses to achieve real 3D visual effects. On the contrary, 3D LED display is a kind of LED display, which allows the audience to enjoy the real 3D image with naked eyes. It is installed outdoors. Like the traditional LED display, it is usually installed on the front of the building to attract potential customers passing by to watch the 3D brand story or product details and make a deep impression.

Recently, more and more brands have foreseen the unexpected brand effect of 3D outdoor advertising LED display as a new method. For example, the Swiss watch manufacturer IWC Schaffhausen displayed the details of the 3D watch on the 3d led screen on the landmark Piccadilly light screen in central London; In Chengdu, China, a giant spacecraft broke through the 3D LED screen. Actress Rosamund Parker shot 3D content and promoted the wheel of time in Paris, New York, Madrid and Tokyo. They have attracted extensive interest and Discussion on social media. The rise of 3D LED displays has witnessed the innovative breakthrough of display technology and the refreshing visual impact. This is not only the future of advertising display, but also the breakthrough innovation of the combination of modern public art and display technology.

Autostereoscopic 3D LED display is a technology that does not require additional 3D glasses or any other tools to produce vivid led 3D performance. People can enjoy the immersive experience of spatial dimension with less visual fatigue.

Video processing: after the host outputs the information stream analog signal of the 3D movie video source, the digital DVI signal is generated. The digital signal passes through the video decoding system to output signals for the left eye and the right eye. The signal is processed by the video display module and then loaded onto the LED screen. Through the binocular parallax principle, the audience can see the 3D effect.

At present, all major cities are making naked eye 3D screens. The more famous ones are Chengdu taiguli business district, Guangzhou jiazhaoye, Chongqing Guanyin bridge, Beijing Wangfujing and so on.

All walks of life are making progress, and the display screen is no exception. It is a new breakthrough in the field of outdoor display. Interactive screens may appear in the future, and people may interact with large screens through sounds, gestures, etc.

In order to create these vivid effects, not only hardware such as LED display and control system must have excellent performance, but also corresponding 3D video production, including angles, details and a series of algorithms.

Since 3D LED display is more commercially feasible than traditional outdoor advertising display in the future, consumers and brands pay more attention to 3D display. The 3D image presented by the 3D outdoor advertising display screen is more realistic and convincing than 2D, because it has a larger area, a higher pixel density, and no edge physical elements that make the image look unreal. Therefore, with the 3D LED screen, your brand image and product display will become lifelike. In addition, 3D images bring viewers a new visual experience that 2D images do not, thus stimulating customers to spend more time exploring your brand and products. 3D technology adds depth to your content and makes your advertising more influential.

Naked eye 3D LED display is a kind of 3D effect that can be seen on the screen without wearing professional glasses. Because of its unique display mode, it also caused a sensation when it was listed. Due to the fierce market, the naked eye 3D technology quickly broke through the visual limitations of many viewpoints, and then there was no breakthrough in the naked eye 3D LED display technology. The whole industry can be said to be silent, and full-dimensional vision is still the development direction of the industry. Why not take this step? In the final analysis, its market awareness is not strong and its market capacity is limited, so it is difficult to form a corresponding industrial chain. Even if enterprises develop new products, there is no market in the industry to consume their products, leading to a waste of R & D funds and seriously hindering the enthusiasm of manufacturers in R & D. What is more fatal is that the high price of the naked eye 3D LED display screen has frightened many users. Moreover, the research and development cost of the naked eye 3D display screen is not low, and the enterprise has the research and development ability and cannot bear the risk of long-term return. Therefore, in the future, most enterprises have turned to other sub fields, making the development of naked eye 3D display industry more difficult.

In each subdivision field of LED display screen, all kinds of display screens have very clear application scene positioning. For example, the small spacing display screen is suitable for indoor application display such as conference command center; Transparent screens are suitable for outdoor advertising and glass film pasting screens, and corresponding technologies are further developed according to their clear positioning to promote a wide range of application scenarios and further promote the research and development of industrial products. But there are always exceptions. Compared with other displays, the application scene of naked eye 3D LED display is fuzzy, and the corresponding technology cannot touch the bypass, making the industry development very slow.

Although the 3D display screen is not as good as various subdivision displays in traditional applications, with the development of visual display technology, it can highlight the display mode of the naked eye 3D LED display screen and make it bright in the application of the dance stage. The unique naked eye 3D LED display mode creates a sense of spatial dimension. Combined with the stage lighting, it creates an immersive lighting and film feast, which brings a strong visual impact to the audience. In addition, in recent years, the demand for artistic performances has been rising, and the future prospect of immersive visual performance stage is very broad.

Babenhausen, Germany, March 16, 2020. Technology company Continental is launching its volume-production display featuring autostereoscopic 3D technology on the market in the HMC Genesis GV80 high-line variant. On the screen, the technology displays three-dimensional scales, pointers and objects, for example displaying a stop sign warning in the driver’s line of sight. No special glasses are required to see the three-dimensional warning signal. Instead, Continental uses parallax barriers – slanted slats that divide the image for the viewer – as if looking at real objects, two different, slightly offset views reach the right and left eye, resulting in the three-dimensional image.

Continental’s interior camera, which detects the driver’s line of sight and adjusts the 3D views to their precise head position, plays an essential role. To prevent drivers from focusing their attention on the 3D screen for too long, the camera also employs attention detection to identify potential moments of driver distraction or fatigue. With the 3D visualization of the instrument cluster, Continental is focused on ensuring the driver is not overloaded with information provided by advanced driver assistance systems, conventional displays, communication services and infotainment applications.

“With our volume-production display featuring autostereoscopic 3D technology, we are raising human-machine interaction to a whole new level and laying the foundations for intuitive communication in the connected cockpit of tomorrow,” said Dr. Frank Rabe, head of the Human Machine Interface business unit at Continental. “To ensure that this gain in safety and comfort does not come at the expense of a lean electronics architecture, we integrated various displays in the center console or dashboard into our Cross Domain Hub.”

Marshall"s OR-70-3D is a 24-inch 1920 x 1200 LCD monitor designed for professional Stereoscopic 3D (S3D) applications. This monitor is only 2-1/4 inches (57mm) deep and uses advanced engineering to deliver natural, flicker-free 3D images by utilizing a circular polarizing filter method when used with battery-free (passive) glasses. The circular polarizing system used employs a 3D Arisawa Xpol® optical filter applied to the surface of the display. The OR-70-3D also has 4 HD-SDI inputs which provide the ability to monitor two S3D (right eye / left eye) HD-SDI signals. By using circular polarized glasses, the user can simultaneously view multiple 3D monitors in a production or controlroom environment. This monitor also supports IMD (In-Monitor Display) and Tally functions through RS-422/RS-485 connections.

Autostereoscopy is any method of displaying stereoscopic images (adding binocular perception of 3D depth) without the use of special headgear, glasses, something that affects vision, or anything for eyes on the part of the viewer. Because headgear is not required, it is also called "glasses-free 3D" or "glassesless 3D". There are two broad approaches currently used to accommodate motion parallax and wider viewing angles: eye-tracking, and multiple views so that the display does not need to sense where the viewer"s eyes are located.lenticular lens, parallax barrier, and may include Integral imaging, but notably do not include volumetric display or holographic displays.

Many organizations have developed autostereoscopic 3D displays, ranging from experimental displays in university departments to commercial products, and using a range of different technologies.Heinrich Hertz Institute (HHI) in Berlin.Sega AM3 (Floating Image System)eye tracking system and a seamless mechanical adjustment of the lenses.

Eye tracking has been used in a variety of systems in order to limit the number of displayed views to just two, or to enlarge the stereoscopic sweet spot. However, as this limits the display to a single viewer, it is not favored for consumer products.

Currently, most flat-panel displays employ lenticular lenses or parallax barriers that redirect imagery to several viewing regions; however, this manipulation requires reduced image resolutions. When the viewer"s head is in a certain position, a different image is seen with each eye, giving a convincing illusion of 3D. Such displays can have multiple viewing zones, thereby allowing multiple users to view the image at the same time, though they may also exhibit dead zones where only a non-stereoscopic or pseudoscopic image can be seen, if at all.

A parallax barrier is a device placed in front of an image source, such as a liquid crystal display, to allow it to show a stereoscopic image or multiscopic image without the need for the viewer to wear 3D glasses. The principle of the parallax barrier was independently invented by Auguste Berthier, who published first but produced no practical results,Frederic E. Ives, who made and exhibited the first known functional autostereoscopic image in 1901.

In the early 2000s, Sharp developed the electronic flat-panel application of this old technology to commercialization, briefly selling two laptops with the world"s only 3D LCD screens.FinePix Real 3D W1 digital camera, which features a built-in autostereoscopic LCD measuring 2.8 in (71 mm) diagonal. The Nintendo 3DS video game console family uses a parallax barrier for 3D imagery; on a newer revision, the New Nintendo 3DS, this is combined with an eye tracking system.

Philips solved a significant problem with electronic displays in the mid-1990s by slanting the cylindrical lenses with respect to the underlying pixel grid.Philips produced its WOWvx line until 2009, running up to 2160p (a resolution of 3840×2160 pixels) with 46 viewing angles.Lenny Lipton"s company, StereoGraphics, produced displays based on the same idea, citing a much earlier patent for the slanted lenticulars. Magnetic3d and Zero Creative have also been involved.

With rapid advances in optical fabrication, digital processing power, and computational models for human perception, a new generation of display technology is emerging: compressive light field displays. These architectures explore the co-design of optical elements and compressive computation while taking particular characteristics of the human visual system into account. Compressive display designs include dualcomputed tomography and Non-negative matrix factorization and non-negative tensor factorization.

Dimension Technologies released a range of commercially available 2D/3D switchable LCDs in 2002 using a combination of parallax barriers and lenticular lenses.SeeReal Technologies has developed a holographic display based on eye tracking.

There are a variety of other autostereo systems as well, such as volumetric display, in which the reconstructed light field occupies a true volume of space, and integral imaging, which uses a fly"s-eye lens array.

Sunny Ocean Studios, located in Singapore, has been credited with developing an automultiscopic screen that can display autostereo 3D images from 64 different reference points.

Many autostereoscopic displays are single-view displays and are thus not capable of reproducing the sense of movement parallax, except for a single viewer in systems capable of eye tracking.

"Resolving the Vergence-Accommodation Conflict in Head-Mounted Displays" (PDF). web.archive.org. 22 September 2022. Archived from the original (PDF) on 22 September 2022. Retrieved 22 September 2022.

Holliman, N.S. (2006). Three-Dimensional Display Systems (PDF). ISBN 0-7503-0646-7. Archived from the original (PDF) on 4 July 2010. Retrieved 30 March 2010.

Ives, Frederic E. (1902). "A novel stereogram". Journal of the Franklin Institute. 153: 51–52. doi:10.1016/S0016-0032(02)90195-X. Reprinted in Benton "Selected Papers n Three-Dimensional Displays"

Lippmann, G. (2 March 1908). "Épreuves réversibles. Photographies intégrales". Comptes Rendus de l"Académie des Sciences. 146 (9): 446–451. Bibcode:1908BSBA...13A.245D. Reprinted in Benton "Selected Papers on Three-Dimensional Displays"

van Berkel, Cees (1997). Fisher, Scott S; Merritt, John O; Bolas, Mark T (eds.). "Characterisation and optimisation of 3D-LCD module design". Proc. SPIE. Stereoscopic Displays and Virtual Reality Systems IV. 3012: 179–186. Bibcode:1997SPIE.3012..179V. doi:10.1117/12.274456. S2CID 62223285.

Lanman, D.; Wetzstein, G.; Hirsch, M.; Heidrich, W.; Raskar, R. (2011). "Polarization Fields: Dynamic Light Field Display using Multi-Layer LCDs". ACM Transactions on Graphics (SIGGRAPH Asia). Cite journal requires |journal= (help)

Chinnock, Chris (11 April 2014). "NAB 2014 – Dolby 3D Details Partnership with Stereolabs". Display Central. Archived from the original on 23 April 2014. Retrieved 19 July 2016.

McAllister, David F. (February 2002). "Stereo & 3D Display Technologies, Display Technology" (PDF). In Hornak, Joseph P. (ed.). Encyclopedia of Imaging Science and Technology, 2 Volume Set (Hardcover). Vol. 2. New York: Wiley & Sons. pp. 1327–1344. ISBN 978-0-471-33276-3.

Dodgson, N.A.; Moore, J. R.; Lang, S. R. (1999). "Multi-View Autostereoscopic 3D Display". IEEE Computer. 38 (8): 31–36. CiteSeerX doi:10.1109/MC.2005.252. ISSN 0018-9162. S2CID 34507707.

"Resolving the Vergence-Accommodation Conflict in Head-Mounted Displays" (PDF). web.archive.org. 22 September 2022. Archived from the original (PDF) on 22 September 2022. Retrieved 22 September 2022.

Since Charles Wheatstone first invented stereoscopy, the research interest in three-dimensional (3D) displays has extended for 150 years, and its history is as long as that of photography (Charles, 1838). As a more natural way to present virtual data, glasses-free 3D displays show great prospects in various fields including education, military, medical, entertainment, automobile, etc. According to a survey, people spend an average of 5 h every day watching display panel screens. The visualization of 3D images will have a huge impact on improving work efficiency. Therefore, glasses-free 3D displays are regarded as next-generation display technology.

Generally, we assign glasses-free 3D displays into three main categories: holographic 3D displays, volumetric 3D displays and autostereoscopic 3D displays (Geng, 2013). A holographic 3D display is a technology that records both the amplitude and phase information of a real object and reproduces it through specific mediums (e.g., photorefractive polymers) (Tay et al., 2008; Blanche et al., 2010). Furthermore, by using a spatial light modulator that directly modulates the coherent wave, computer-generated hologram systems can be implemented via numerical simulation. (Hahn et al., 2008; Sasaki et al., 2014). Currently, powerful acceleration chips or video processors have enabled the reproduction of high-quality 3D holograms at video rates (An et al., 2020; Shi et al., 2021). In the future, real-time holographic 3D displays will have wide applications in mobile displays and AR displays (Peng et al., 2021; Lee et al., 2022). Volumetric 3D display is another technology that generates luminous image points (i.e., voxels) in space via special media, such as trapped particles and fluorescent screens. These image points form 3D graphics that can be observed within 360° (Kumagai et al., 2015; Kumagai et al., 2018; Smalley et al., 2018; Hirayama et al., 2019). Both the holographic 3D display and volumetric 3D display require a large amount of data to provide 3D content, which brings challenges to data processing and transportation.

In contrast, autostereoscopic 3D displays reduce computing costs by discretizing a continuously distributed light field of 3D objects into multiple “views”. The properly arranged perspective views can approximate the 3D images with motion parallax and stereo parallax. Moreover, by modulating the irradiance pattern of each view, only a small number of views are required to reconstruct the light field. A typical autostereoscopic 3D display only needs to integrate two components: an optical element and an off-the-shelf refreshable display panel (e.g., liquid crystal display, organic light-emitting diode display, light-emitting diode display) (Dodgson, 2005). With the advantages of a compact form factor, ease of integration with flat display devices, ease of modulation, and low cost, autostereoscopic 3D displays can be applied in portable electronics and redefine human-computer interfaces. The function of the optical element in an autostereoscopic 3D display is to manipulate the incident light and generate a finite number of views. To improve the display effect, the optical elements also need to modulate the views and angular separation between views, which is called the “view modulator” in this paper. View modulators represent a special class of optical elements that are used in glass-free 3D displays for view modulation, such as parallax barriers, lenticular lens arrays, and metagratings.

One of the most critical issues in autostereoscopic 3D displays is how to design view modulators. When we design view modulators, several essential problems need to be considered that are directly related to 3D display performance (Figure 1): 1) To minimize crosstalk and ghost images, the view modulators should confine the emerging light within a well-defined region; 2) To address the vergence-accommodation conflict, the view modulators need to provide both correct vergence and accommodation cues. Vergence-accommodation conflict occurs when the depth of 3D images induced by binocular parallax lies in front of or behind the display screen, whereas the depth recognized by a single eye is fixed at the apparent location of the physical display panel because the image observed by a single eye is 2D (Zou et al., 2015; Koulieris et al., 2017); 3) To achieve a large field of view (FOV), the view modulators need to precisely manipulate light over a large steering angle; 4) For an energy-efficient system, the light efficiency of the view modulators needs to be adequate. In addition to these four important factors that affect the optical performance of 3D displays, there are some additional features that should be addressed in applications; 5) To maintain a thin form factor and be lightweight for portable electronics, the design of view modulators should be elegant with as few layers or components as possible; 6) To solve the tradeoff between spatial resolution, angular resolution, and FOV, the view modulators should manipulate the shape of view for variant information density. 7) In window display applications, the view modulators should be transparent to combine virtual 3D images with physical objects for glasses-free augmented reality display.

Depending on the types of adopted view modulators, autostereoscopic 3D displays can be divided into geometrical optics-based and planar optics-based systems. With regard to geometrical optics-based 3D displays, the most representative architectures are parallax barrier or lenticular lens array-based, microlens array-based and layer-based systems (Ma et al., 2019). The parallax barrier or lenticular lens array was first integrated with flat panels and applied in 3D mobile electronic devices because of the advantages of utilizing existing 2D screen fabrication infrastructure (Ives, 1902; Kim et al., 2016; Yoon et al., 2016; Lv et al., 2017; Huang et al., 2019). For improved display performance, aperture stops were inserted into the system to reduce the crosstalk by decreasing the aperture ratio; however, this strategy comes at the expense of light efficiency (Wang et al., 2010; Liang et al., 2014; Lv et al., 2014). Microlens array-based 3D display, i.e., integral imaging display generates stereoscopic images by recording and reproducing the rays from 3D objects (Lippmann, 1908; Martínez-Corral and Javidi, 2018; Javidi et al., 2020). It can present full motion parallax by adding light manipulating power in a different direction. Recently, a bionic compound eye structure was proposed to enhance the performance of integral imaging 3D display systems. With proper design based on geometric optics, the 3D display prototype can be used to obtain a 28° horizontal, 22° vertical viewing angle, approximately two times that of a normal integral imaging display (Zhao et al., 2020). In another work, an integral imaging 3D display system that can enhance both the pixel density and viewing angle was proposed, with parallel projection of ultrahigh-definition elemental images (Watanabe et al., 2020). This prototype display system reproduced 3D images with a horizontal pixel density of 63.5 ppi and viewing angles of 32.8° and 26.5° in the horizontal and vertical directions, respectively. Furthermore, with three groups of directional backlight and a fast-switching liquid crystal display (LCD) panel, a time-multiplexed integral imaging 3D display with a 120° wide viewing angle was demonstrated (Liu et al., 2019). The layer-based 3D display invented by Lanman and Wetzstein (Lanman et al., 2010; Lanman et al., 2011; Wetzstein et al., 2011; Wetzstein et al., 2012) used multiple LCD screen layers to modulate the light field of 3D objects. This display can provide both vergence and accommodation cues for viewers with limited fatigue and dizziness (Maimone et al., 2013). Nevertheless, its FOV is limited by the effective size of the display panel. Moreover, layer-based 3D displays also suffer from a trade-off between the depth of field and the complexity of the system (i.e., the layer number for the display devices). In general, geometrical optics-based autostereoscopic 3D displays have the advantages of low cost and thin form factors that are compatible with 2D flat display panels. However, we still have a fair way to go due to the tradeoffs among the resolution, FOV, depth cues, depth of field and form factor (Qiao et al., 2020). Alleviating these tradeoffs and improving the image quality to provide more realistic stereoscopic vision has opened up an intriguing avenue for developing next-generation 3D display technology.

Fast-growing planar optics have attracted wide attention in various fields because of their outstanding capability for light control (Genevet et al., 2017; Zhang and Fang, 2019; Chen and Segev, 2021; Tabiryan et al., 2021; Xiong and Wu, 2021). In the field of glasses-free 3D displays, planar optical elements, such as diffraction gratings, diffractive lenses and metasurfaces, can be used to modulate the light field of 3D objects at the pixel level. With proper design, planar optical elements at the micro or nano scale provide superior light manipulation capability in terms of light intensity, phase, and polarization. Therefore, planar optics-based glass-free 3D displays have several merits, such as reduced crosstalk, no vergence-accommodation conflict, enhanced light efficiency, and an enlarged FOV. Figure 2 shows the developing trend for 3D display technologies with regard to the revolution of view modulators. Planar optics are becoming the “next-generation 3D display technology” because of outstanding view modulation flexibility.

FIGURE 2. Schematic of the development of glasses-free 3D displays with regard to the revolution of view modulators. LLA: Lenticular lens array; MLA: Microlens array.

In this review, the critical challenges for glasses-free 3D displays are analyzed. Planar optics-based 3D displays suggest a variety of solutions for 3D displays, which will be reviewed in the section Glasses-Free 3D Display Based on Planar Optical Elements. As a specific application and an appealing feature, augmented reality (AR) 3D displays enabled by planar optics will be comprehensively introduced in the section Glasses-Free augmented reality 3D display based on planar optical elements. In addition to the design of view modulators, the fabrication of view modulators is another challenge that hinders the development of 3D displays. Therefore, in the section Fabrication of Large-Scale Micro/Nanostructures on View Modulators for 3D Displays, we will highlight multiple micro/nanofabrication methods for view modulators in 3D displays. In the section Conclusions and Outlook, the current status for glasses-free 3D displays and glasses-free AR 3D displays will be summarized. Finally, future directions and potential applications are suggested in the section Conclusions and Outlook.

Diffraction gratings are unique components that can split incident light into many spatial directions simultaneously and have been widely used in steering devices, such as spectrometers, optical waveguides and laser resonators (Zola et al., 2019; Cao et al., 2020; Görrn et al., 2011; Zhang et al., 2019; Liu et al., 2020). Fattal et al. employed diffraction gratings in a 3D display and proposed a directional diffractive backlight to produce full parallax views within a wide FOV (Fattal et al., 2013). The key elements in the backlight were pixelated grating patterns fabricated by electron-beam lithography. Both passive and active prototypes provided 64-view images within a FOV of 90°. The diffractive wide-angle backlight is regarded as a revolutionary 3D display (https://www.technologyreview.com/innovator/david-fattal). It has opened up rich opportunities for planar optics-based glasses-free 3D displays.

On this basis, a holographic sampling 3D display was proposed by combining a phase plate with a thin film transistor-LCD panel (Wan et al., 2017) (Figure 3A). The phase plate modulates the phase information, while the LCD panel provides refreshable amplitude information for the light field. Notably, the period and orientation of the diffraction gratings in each pixel are calculated to form converged beams instead of (semi)parallel beams in a geometrical optics-based 3D display. As a result, the angular divergence of target viewpoints (1.02°) is confined close to the diffraction limit (0.94°), leading to significantly reduced crosstalk and ghost images (Figures 3B,C). The researchers further presented a holographic sampling 3D display based on metagratings and demonstrated a video rate full-color 3D display prototype with sizes ranging from 5 to 32 inches (Figure 3D) (Wan et al., 2020). The metagratings on the view modulator were designed to operate at the R/G/B wavelength to reconstruct the wavefront at sampling viewpoints with the correct white balance (Figure 3E). By combining the view modulator, a LCD panel and a color filter, virtual 3D whales were presented, as shown in Figure 3F. To address the vergence-accommodation conflict in 3D displays, a super multiview display was also proposed based on pixelated gratings. Closely packaged views with an angular separation of 0.9° provide a depth cue for the accommodation process of the human eye (Wan et al., 2020).

FIGURE 3. (A) Schematic of the proposed holographic sampling 3D display. (B) Photograph of 4 views and the light intensity distribution at 4 views. (C) 3D images of a car running through trees. (D) Schematic of the full-color video rate holographic sampling 3D display. (E) The radiation pattern measured from a 16-view point view modulator. (F) 3D images of whales and logos. [(A–C) Reproduced from Wan et al. (2013). Copyright (2021) with permission from Optica Publishing Group. (D–F) Reproduced from Wan et al. (2020). Copyright (2021) with permission from Elsevier B.V.].

To summarize, diffraction grating-based 3D displays have the advantages of minimum crosstalk, reduced vergence-accommodation conflict, tailorable view arrangement, continuous motion parallax and a wide FOV. Nevertheless, the experimental diffraction efficiency of binary gratings is approximately 20%, leading to inevitable high-power consumption. On this basis, diffractive lenses and metasurfaces are employed for 3D displays.

Light efficiency is a crucial parameter in glass-free 3D display systems. Diffractive lenses with blazed structures can be used to focus light together, thereby showing higher light efficiency in 3D displays than diffraction gratings. As shown in Figures 4A,B, pixelated blazed diffractive lenses are introduced in a 3D display to form four independent convergent views, while the amplitude plate provides the images at these views. The system has the following benefits. First, each structured pixel on the view modulator is calculated by the relative position relationship between the pixel and viewing points. These accurately calculated aperiodic structures can improve the precision of light manipulation, thereby eliminating crosstalk and ghost images. Second, the 4-level blazed diffractive lens greatly increases the diffraction efficiency of the grating-based 3D display from 20 to 60% (Zhou et al., 2020). In another work, a view modulator covered with a blazed diffractive lenticular lens was proposed in a multiview holographic 3D display (Hua et al., 2020). This system redirected the diverging rays to shape four extended views with a vertical FOV of 17.8°. In addition, the diffraction efficiency of the view modulator was increased to 46.9% using the blazed phase structures. Most recently, a vector light field display with a large depth of focus was proposed based on an intertwined flat lens, as shown in Figures 4C,D. A grayscale achromatic diffractive lens was designed to extend the depth of focus by 1.8 × 104 times. By integrating the intertwined diffractive lens with a liquid crystal display, a 3D display with a crosstalk below 26% was realized over a viewing distance ranging from 24 to 90 cm (Zhou et al., 2022).

FIGURE 4. (A) Schematic of a glass-free 3D display based on a multilevel diffractive lens. (B) 3D images of letters or thoracic cages in a blazed diffractive lens-based 3D display. (C) Schematic of a vector light field display based on a grayscale achromatic diffractive lens. (D) Full color 3D images of letters and the thoracic cage produced by the intertwined diffractive lens-based 3D display. [(A,B) Reproduced from Zhou et al. (2020). Copyright (2021), with permission from IEEE. (C,D) Reproduced from Zhou et al. (2022). Copyright (2022), with permission from Optica Publishing Group.].

In summary, coupled with various design approaches, an optimized diffractive lens can enable the realization of a high-quality full spectrum in imaging applications (Peng et al., 2015; Heide et al., 2016; Peng et al., 2016; Peng et al., 2019). The design of diffractive lenses in 3D displays bears similarities to the design in imaging. This solves the problem of light efficiency in diffractive grating-based 3D displays. The optimized lens features a high light efficiency, wide spectrum response and large depth of focus, which benefits glasses-free 3D displays in terms of brightness, color fidelity, and viewing depth. However, the minimum feature size of diffractive lenses is generally larger than that of nanogratings due to the fabrication limit, resulting in a reduced viewing angle.

We believe that metasurfaces can be used in 3D displays because of their unprecedented capability to manipulate light fields. In 2013, 3D computer-generated holography image reconstruction was demonstrated in the visible and near-infrared range by a plasmonic metasurface composed of pixelated gold nanorods (Huang et al., 2013) (Figures 5A,B). The pixel size of the metasurface hologram was only 500 nm, which is much smaller than the size of the hologram pixels generated by spatial light modulators or diffractive optical elements. As a result, a FOV as large as 40° was demonstrated. To correct chromatic aberration in integral imaging 3D displays, a single polarization-insensitive broadband achromatic metalens using silicon nitride was proposed (Fan et al., 2019) (Figures 5C,D). Each achromatic metalens has a diameter of 14 µm and was fabricated via the electron beam lithography technique. The focusing efficiency was 47% on average. By composing a 60 × 60 metalens in a rectangular lattice, a broadband achromatic integral imaging display was demonstrated under white light illumination. To address the tradeoff between spatial resolution, angular resolution, and FOV, a general approach for foveated glasses-free 3D displays using the two-dimensional metagrating complex was proposed recently (Figure 5E) (Hua et al., 2021). The dot/linear/rectangular hybrid views, which are shaped by a two-dimensional metagrating complex, form spatially variant information density. By combining the two-dimensional metagrating complex film and a LCD panel, a video rate full-color foveated 3D display system with an unprecedented FOV up to 160° was demonstrated (Figure 5F). Compared with prior work, the proposed system makes two breakthroughs: First, the irradiance pattern of each view can be tailored carefully to avoid both crosstalk and discontinuity between views. Second, the tradeoffs between the angular resolution, spatial resolution and FOV in 3D displays are alleviated.

FIGURE 5. (A) Schematic of a plasmonic metasurface for 3D CGH image reconstruction. (B) Experimental hologram images for different focusing positions along the z direction. (C) Schematic of the broadband achromatic metalens array for a white-light achromatic integral imaging display. (D) Reconstructed images for the cases that “3” and “D” lie on the same depth plane or on different depth planes, respectively. Scale bar, 100 µm. (E) Schematic of a foveated glasses-free 3D display using the two-dimensional metagrating complex. (F) “Albert Einstein” images in the foveated 3D display system. [(A,B) Reproduced from Huang et al. (2013). Copyright (2021), with permission from Springer Nature. (C,D) Reproduced from Fan et al. (2019). Copyright (2021), with permission from Springer Nature. (E,F) Reproduced from Hua et al. (2021). Copyright (2021), with permission from Springer Nature.].

To summarize, metasurfaces provide a solution that maintains both a large FOV and reasonable light efficiency. Moreover, the superior light manipulation capability provides an inspiring foveated glasses-free 3D display solution for an intrinsic tradeoff between resolution and viewing angle in 3D displays. Like all metamaterial-based photonic devices, the mass fabrication of metasurfaces is the major issue that prevents industrial application of this technology.

As mentioned above, we have reviewed the research progress for planar optics-based glass-free 3D displays: diffraction grating-based, diffractive lens-based and metasurface-based. Compared with geometric optics-based 3D displays, these displays all have common advantages, such as high precision control at the pixel level, high degrees of freedom in design, and compact form factors. On the other hand, they have their own properties in terms of light efficiency, FOV, viewing distance, and fabrication scaling, as listed in Table 1. The diffraction grating-based method has both a large FOV with continuous motion parallax and large fabrication scaling. Although the bandwidth of the diffraction grating is limited, a full-color display can still be realized by integrating a color filter. As a result, the problem of selective bandwidth operation is trivial in 3D displays. However, the low light efficiency of binary gratings can be problematic because of the increased power consumption, especially in portable electronics. The diffractive lens-based approach greatly improves the light efficiency. Moreover, through proper design, an intertwined diffractive lens can be used to realize a large viewing distance and broadband spectrum manipulation. Nevertheless, the viewing angle of a diffractive lens-based 3D display is limited by the numerical aperture. The metasurface-based technique has the advantages of medium light efficiency, a large FOV and broadband spectrum response. Therefore, metasurfaces can provide better 3D display performance in terms of color fidelity. Furthermore, the subwavelength dimensions of metasurfaces ensure their flexibility for view manipulation. However, the complexity and difficulty in nanofabrication hinders the application of metasurfaces in large-scale displays.

Most recently, augmented reality (AR), as an interactive display that fuses the virtual world with reality, has become an aggressive research field that attracts broad attention from researchers, investors and scientists (Chang et al., 2020; Xiong et al., 2021). Glasses-free AR 3D displays are of special interest because of the huge demand in many applications, such as head-up displays in vehicles, education, and exhibitions. Although near-to-eye displays for AR technologies based on wearable devices can be implemented by various methods, including free-form optics, holographic optical elements, surface relief gratings, or metasurfaces, the realization of glasses-free AR 3D displays is a much harder task because of the uncertain spatial relationship between the display screen and observers. Glasses-free AR 3D displays can be assigned to either reflection-type and optical see-through type displays. Li et al. adopted a mirror-based pinhole array to demonstrate a reflective AR 3D display system based on an integral imaging display (Li et al., 2019). Recently, they improved the performance of the reflection-type AR 3D system with high definition and high brightness based on the use of a reflective polarizer (Li et al., 2021). However, in the reflection-type AR 3D display, virtual images are fused with mirror images of the real scene rather than the real scene itself.

The optical see-through glasses-free AR 3D display permits people to perceive real scenes directly through a transparent optical combiner (Hong et al., 2016; Mu et al., 2020). Generally, it occupies the mainstream for various AR 3D display technologies and can be realized by using geometric optical elements, holographic optical elements (HOE) and metagratings. In 2020, a lenticular lens-based light field 3D display system with continuous depth was proposed and integrated into AR head up display optics (Lee et al., 2020). This integrated system can generate stereoscopic virtual images with a FOV of 10° × 5°.

The HOE is an optical component that can be used to produce holographic images using principles of diffraction, which is commonly used in transparent displays, 3D imaging, and certain scanning technologies. HOEs share the same optical functions as conventional optical elements, such as mirrors, microlenses, and lenticular lenses. On the other hand, they also have unique advantages of high transparency and high diffraction efficiency. On this basis, the integral imaging display can be integrated with an AR display based on a lenticular lens or microlens-array HOE (Li et al., 2016; Wakunami et al., 2016). Moreover, the HOE can be recorded by wavelength multiplexing for full-color imaging (Hong et al., 2014; Deng et al., 2019) (Figure 6A). A high transmittance was achieved at all wavelengths (Figures 6B,C). A 2D/3D convertible AR 3D display was further proposed based on a lens-array holographic optical element, a polymer dispersed liquid crystal film, and a projector (Zhang et al., 2019). Controlled by voltage, the film can switch the display mode from a 2D display to an optical see-through 3D display.

FIGURE 6. (A) Work principles for a lens-array HOE used in the OST AR 3D display system. (B) Transmittance and reflectance of the recorded lens-array HOE. (C) 3D virtual image of the lens-array HOE-based full color AR 3D display system. (D) Schematic for spatial multiplexing metagratings for a full-color glasses-free AR 3D display. (E) Transmittance of the holographic combiner based on pixelated metagratings. (F) 3D virtual image of the metagratings-based glasses-free AR 3D display system. (G) Schematic of the pixelated multilevel blazed gratings for a glass-free AR 3D display. (H) Principles of the pixelated multilevel blazed gratings array that form viewpoints in different focal planes. (I) 3D virtual image of the blazed gratings-based glasses-free AR 3D display system. [(A–C) Reproduced from Hong et al. (2014). Copyright (2021), with permission from Optica Publishing Group. (D–F) Reproduced from Shi et al. (2020). Copyright (2021), with permission from De Gruyter. (G–I) Reproduced from Shi et al. (2021). Copyright (2021), with permission from MDPI.].

In fact, AR 3D displays based on lens arrays form self-repeating views. Thus, both motion parallax and FOV are limited. Moreover, false depth cues for 3D virtual images can be generated due to the image flip effect. Correct depth cues are particularly important for AR 3D displays when virtual images fuse with natural objects. On this basis, a holographic combiner composed of spatial multiplexing metagratings was proposed to realize a 32-inch full-color glass-free AR 3D display, as shown in Figure 6D (Shi et al., 2020). The irradiance pattern for each view is formed as a super Gaussian function to reduce crosstalk. A FOV as large as 47° was achieved in the horizontal direction. For the sake of correct white balance, three layers of metagratings are stacked for spatial multiplexing. The whole system contains only two components: a projector and a metagrating-based holographic combiner. Moreover, the transmittance is higher than 75% over the visible spectrum (Figures 6E,F), but the light efficiency of metagrating is relatively low (40% in theory and 12% in experiment). To improve the light efficiency, pixelated multilevel blazed gratings were introduced for glasses-free AR 3D displays with a 20 inch format (Figures 6G,H) (Shi et al., 2021). The measured diffraction efficiency was improved to a value of ∼53%. The viewing distance for motion parallax was extended to more than 5 m, benefiting from the multiorder diffraction light according to harmonic diffraction theory (Figure 6I).

We introduce a summary of various methods for realizing glasses-free AR 3D displays. As shown in Table 2, the optical see-through combiner outweighs the reflection type method for a more natural fusion with the physical world. In all optical see-through combiners, holographic optical element-based combiners have the advantages of high diffraction efficiency and high transparency. However, they suffer from a limited FOV and motion parallax. The metagrating-based combiner offers an accurate depth cue over a large FOV. The multilevel blazed grating-based method further improves the light efficiency and viewing depth due to multiorder diffraction.

The development of high-throughput micro/nanofabrication methods is essential for large view modulators. To fabricate the diffraction gratings or metagratings at a high throughput, a flexible lithography system was proposed (Figure 7A) (Wan et al., 2016). The nanogratings in this system were fabricated pixel by pixel. Through one exposure, a nanograting pixel with a size on the scale of tens of microns was formed. Therefore, the throughput can be much faster than that obtained by an electron beam lithography system that works via a sequential writing process. In addition, the periodic tuning accuracy of the fabricated gratings can be less than 1 nm. Using the proposed lithography system, a 32-inch view modulator with a minimum feature size of 300 nm was successfully prepared for a glass-free 3D display (Figures 7B,C). This view modulator has a total of 24,883,200 pixelated metagratings.

To efficiently fabricate multilevel microstructures, a grayscale laser direct writing system can be employed, as shown in Figure 7D. The system mainly contains a laser, an electronically programmable spatial light modulator device and an objective lens. The spatial light modulator device loads the hologram patterns