Sharp's Two-Way Viewing-Angle LCD

See double. (No booze required.)

Every once in a while, a new technology pops up that is so cool and so different that it has to create its own market. Sharp's sexy-sounding two-way viewing-angle LCD technology is just such a thing. It allows for diverse and unique uses that were previously not possible—or at least difficult.


First, a Primer
I'm going to shorten two-way viewing-angle LCD to TWVA to make it easier to read and type. TWVA is based around LCD technology, and, to understand TWVA, you need at least a basic understanding of LCD. Unlike plasma and CRT, the element that makes the image on a liquid-crystal display doesn't also make the light. At the back of an LCD is a series of lamps, often fluorescents similar to the ones found in offices. Light likes to travel in every direction it can. For an LCD to work, the lamps' rays need to all march in the same direction. To do this, the lamps send the light through a polarizing layer that makes the rays all head straight for the front of the display. In between the light and its freedom are two things—the liquid-crystal layer and another polarizing layer. One way to understand the liquid-crystal layer is to picture a bunch of cigars, one assigned to each pixel on the display. These cigars' job is to either let the light pass through unmolested (an "on" pixel), or to twist the light 90 degrees so that it is blocked by the second polarizing layer (an "off" pixel). By applying different amounts of power, you can twist the light in different increments. For 50-percent brightness, the cigars twist so that the polarizing layer blocks half the light. This occurs on a per-pixel basis. For color displays, there are three times as many pixels horizontally (also called subpixels or pels), one for each color (red, green, and blue).

What Starts as a Downside. . .
One issue with LCD technology is that, because the light is polarized, it only likes to go in one direction. So, if you're viewing an LCD from directly in front, you'll get a good show, but a viewer seated off to the side won't. LCDs have come a long way in reducing this effect, but the vast majority fall far short of their 170-degree viewing-angle claims. Ironically, it's this very effect that makes TWVA and all its wonders possible.

. . .Turns into a Benefit.
Let's say that, instead of trying to optimize the viewing experience for wide audience spacing, you purposely tried to make the viewing experience different for people sitting on opposite ends of a couch. (I'll get to why later.) You do this by adding a parallax barrier to the front of the display. Think of it as a picket fence. Depending on where you're sitting in relation to the "fence" in front of the screen, you can only see certain pixels. Move, and you will see different pixels. Do this right, and the people seated to the left only see what was intended for them, and those sitting to the right only see what was intended for them. 406gear.2.jpg

Ummmm, But Why?
Oh, the uses. Say you want to watch When Harry Met Sally. You're wearing your favorite flannel pj's and have your box of tissues ready. Your wife, like she always does, plops herself down, grabs the remote, and turns on the game. "But honey," you say, "I wanted to watch my Nora Ephron masterpiece." Well, don't fret. If you have a TWVA monitor, you can activate the TWVA feature. (You'll be able to turn it on and off.) Now all you both need to do is slide away from the center, and you can have the good cry you wanted, while your wife can watch the Sox lose again. Harmony is restored. What's cool about this technology is that it doesn't end there.

Drive in Peace
Picture a similar argument in the car. She wants you to stop and ask for directions because you have the directional sense of a lemming. You just want to drive the 8 hours to her mother's house in the last peace you'll have for a week. With a TWVA monitor in the dash, you can have the GPS navigation going while she watches a movie. Because you can't see the movie from your seat, you needn't try to match Steve McQueen powerslide for powerslide. What's better is that your wife can't see that you aren't using the GPS because you're actually trying to get lost.


Another variation on this technology can be implemented on a computer screen. You can see the screen just fine, but the nosy people sitting to either side of you can't see your e-mails. Or, in a meeting, your audience can look at your PowerPoint presentation, while you can see your notes. Let's say you're sitting next to your boss in a meeting. He looks over at the screen and sees sales figures. You, on the other hand, are reading your personal e-mails.

For video games, it's even better. Instead of a split-screen multiplayer, you can have the whole screen for your game, and your opponent also has the whole screen (while sitting on the other end of the couch). Unfortunately, this limits your ability to cheat by looking at the other half of the screen.

But Wait, There's More.
Your eyes are about 6 centimeters apart—less if you're a cat, more if you're, say, a hammerhead shark. Knowing this, you can use TWVA to create a different effect. With a directional LCD, the parallax barrier diverts the light by about 40 degrees off center in each direction. If you narrow the light's angle by about 6 degrees, the display can send similar but slightly different signals to each of your eyes. Historically, viewers have created the same effect by wearing red and blue filters in front of their eyes. That's right—you can have 3-D without funny glasses. Sure, the field of view will be limited, as would the seating range, but it should work pretty well. There is also no requirement for size, so your cell phone's display could be 3-D—or your iPod's. Believe it or not, some of these 3-D displays are already available in this country.

Can I Get One?
The TWVA displays aren't available just yet, but they are coming. I'm willing to bet that, at first, we'll see TWVA displays on the industrial side. Everywhere you look now there's an LCD or plasma displaying advertising. With a TWVA LCD, companies could display different ads for the people coming and those going. Or bars could show two games at once. On the home side, TWVA sets will certainly be a step up over a regular LCD. But, for some people in some situations, this could be the perfect technology. The 3-D aspect is what I am tentatively excited about. George Lucas and a few others have been pushing 3-D recently, and maybe this is the technology that will help get their poorly written dreams into homes. Then again, there seems to have been a push for 3-D every few years, dating back to the start of 2-D. I'll see if I can get one in and play with it.

Until these TWVA displays hit the market, our double vision will have to be induced by tequila.