Is It Possible to Watch 3D Without Glasses?

The State of Glasses-Free 3D Viewing

Young couple watching TV in 3D
simonkr / Getty Images

Currently, all 3D viewing that is in use and available for the home or the cinema has to be done by wearing 3D glasses. However, there are technologies in various stages of development that can enable you to see a 3D image on a TV or other type of video display device without glasses.

The Challenge: Two Eyes, Two Separate Images

The main issue with regards to viewing 3D on a TV (or video projection screen) is that humans have two eyes, each separated by a couple of inches.

This physical state is the reason we are able to see 3D in the real world as each eye sees a slightly different view of what is in front of it, and then transmits that view to the brain. The brain then combines those two images, which results incorrectly viewing a natural 3D image.

However, since artificially created images displayed on a TV or on projection screen are flat (2D), both eyes are seeing the same image and although still and motion photography "tricks" can provide some sense of depth and perspective within the displayed image, there are not enough spatial cues for the brain to accurately process what is being viewed as a natural 3D image.

How 3D Traditionally Works for TV Viewing

What engineers have done to solve the problem of seeing 3D from an image displayed on a TV, movie, or home video projector and screen is to send two slightly different signals that are each targeted to your left or right eye. This can be accomplished in several ways.

Where 3D glasses come in is that each left and right lens each see a slightly different image and send that information to your left and right eye and then, your eyes send that information onto the brain — the result, your brain is fooled into created the perception of a 3D image.

Obviously, this process isn't perfect, as the information cues using this artificial method are not as detailed as the cues received in the natural world, but, if done properly, the effect can be very convincing.

The two parts of a 3D signal that reaches your eyes can be transmitted several ways, which requires the use of either Active Shutter or Passive Polarized Glasses to see the result. When such images are viewed without 3D glasses, the viewer sees two overlapping images that look slightly out of focus.

Progress Towards Glasses-Free 3D

Exploded schematic of non-glasses 3D enabled television
​Stream TV Networks, Inc

Although glasses-required 3D viewing is pretty well accepted for movie-going experience, consumers have never totally accepted that requirement for viewing 3D at home. As a result, there has been a long-running quest to bring glasses-free 3D to consumers.

There are several ways to execute glasses-free 3D, as outlined by Popular Science, MIT, Dolby Labs, and Stream TV Networks.

Shown in the image is an example from Stream TV Networks (Ultra-D) of how a TV needs to be constructed so that it can display 3D images for viewing without the need for glasses.

Glasses-Free 3D Products

Based on these efforts, no-glasses 3D viewing is becoming available on some smartphones and tablets and portable game devices. However, in order to view the 3D effect, you have to look at the screen from a specific viewing angle, which is not a big issue with small display devices, but when scaled up to large screen TV sizes, it makes implementing glasses-free 3D viewing very difficult, and expensive.

The no-glasses 3D concept has been demonstrated in a larger screen TV screen form factor as Toshiba, Sony, Sharp, Vizio, and LG have all showed glasses-free 3D prototypes at various trade shows over the years, and, in fact, Toshiba briefly marketed glasses-free 3D TVs in a few select Asian markets.

However, glasses-free 3D TVs are now marketed more to the business and institutional community. They are being used more and more in digital signage display advertising. However, they are not generally promoted to consumers in the U.S. However, you may be able to purchase one of the professional models offered by Stream TV networks/IZON technologies. The sets are available in the 50 and 65-inch screen sizes and carry very high price tags.

On the other hand, what makes these TVs groundbreaking is that they sport 4K resolution (four times more pixels than 1080p) for 2D images, and full 1080p for each eye in 3D mode, and while the effect 3D viewing is narrower than viewing 2D on a same screen size set, it is wide enough for two or three people sitting on a couch to see an acceptable 3D effect. It is also important to note that not all glasses-free 3D TVs or monitors can display images in 2D.

The Bottom Line

3D viewing is at an interesting crossroads. Although TV makers have discontinued glasses-required 3D TVs for consumers many video projectors still offer 3D viewing capability as they are used in both home and professional settings — however, that still requires viewing using glasses.

On the other hand, glasses-free 3D TV within the commonly available LED/LCD TV platform familiar to consumers has made great strides, but sets are expensive and bulky compared to their 2D counterparts. Also, use of such sets is more confined to professional, business, and institutional applications.

However, research and development continues and eventually we may see 3D TV make a comeback if the glasses-free option becomes readily available and affordable.

In addition, James Cameron, who sparked the "modern" use of 3D for entertainment viewing, is working on technology that may bring glasses-free 3D viewing to the commercial cinema — which would mean no more glasses to watch that blockbuster movie at the movie theater.

This may not be possible with current projectors and screens, but large-scale parallax barrier and micro-LED display technologies may hold the key.