Prysm, Inc. (San Jose, CA), formerly known by its stealth name "Spudnik," has gone public with its laser phosphor display (LPD) technology. We have been tracking the company for some time and now we can talk about them. Prysm will demonstrate at ISE 2010, February 2nd - 4th in Amsterdam.

Matt Brennesholtz
Insight Media Analyst

In anticipation of this I had a chance to talk to Amit Jain, CEO of Prysm. He said the ISE show is not a formal product launch; Prysm is using it as a chance to educate potential customers and channels as to the advantages of LPD technology. In addition to the San Jose headquarters, immediately after ISE they will open a UK office to service customers in Europe, the Middle East and Africa. He added the formal product launch, including first shipments, will occur later, but still in H1′10.

The LPD system is a tiled, rear projection system with 25" tiles, but with a twist. Each tile uses scanned lasers, similar to the lasers used in a Blu-ray system. These lasers are violet, not a visible blue color. When the laser beam strikes the structured phosphor screen, the laser excites the red, green and blue phosphors to generate the visible image. The lasers are modulated at the sub-pixel rate and indexed so, for example, the laser is turned on with the correct intensity for the red output when the laser is aimed at the red phosphor.

This is similar to the old beam-index color CRT, a system which failed primarily because the electron beam focus was not good enough at high power and the control circuitry to index the beam on the correct phosphor was not sophisticated enough. With lasers, there should be no problem with focus and with modern ASICs, there should be no problem with sophisticated control.

The system shares one advantage with CRTs and plasma: emission from phosphors is typically Lambertian (uniform with angle), giving the system a very wide and uniform viewing angle. This wide viewing angle is an essential requirement for many applications of tiled displays.

Since the laser in a Prysm LPD is completely enclosed and shielded from the viewer by the phosphor screen, these systems are laser safety Class 1. The system includes interlocks to prevent operation of the lasers if the enclosure is compromised.

Another advantage of the technology, according to Jain, is its very high energy efficiency. The system consumes about 100W/M2 of display area when producing a luminance of several hundred nits. He says the energy consumption is even less when reduced luminances are needed, as in a control room application. According to Jain, this is significantly less than DLP-based rear projection cubes with LED illumination.

We see DLP cubes as Prysm’s main competition. This low energy consumption is desirable not only in its own right, but also puts less of a burden on the building air conditioning, allowing installations in locations where it may not have been feasible with higher-power consumption tiles. In addition, the low power allows the system, depending on the size of the tile array, to be plugged into a convenient 110V AC outlet, without special wiring.

Typical applications would include all the applications such as signage and control rooms where normal tiled displays are used. According to Jain, additional applications such as signage in stores are enabled by the small footprint and the low impact on the building infrastructure. The very narrow gap between tiles, about 0.25mm, will also help in these sorts of applications.

Jain says the display refreshes at 240Hz. This not only enables very smooth motion, but allows the system to be used as an eye-sequential 3D display. He also suggested it could be used, with the proper glasses, to show 4 different 60Hz images. This might be desirable in a museum, for example, where the same display can be used to show multiple screens of information simultaneously to different viewers. Or, perhaps, it could show 2 different 3D images on the same screen to a pair of gamers.

When asked about cost, Jain declined to comment except to say he recognized that their display must not only compete on energy efficiency and image quality, but must be cost competitive with alternative display technology. He said Prysm displays will, in fact, compete fully on a cost basis. He added that Prysm plans on manufacturing the displays themselves. The two basic technologies used, lasers and phosphors, have much wider application than just the LPD. Therefore he expected considerable advancements in these technologies in the years to come, further reducing Prysm costs, reducing the energy consumed and improving the image quality.

"We have spent the last 4 years developing a truly disruptive technology with a team of the best technologists in the industry," said Jain. "LPD is generating excitement from prospective customers around the world. Although we knew that image quality would appeal to customers everywhere, we have also found that the LPD energy efficiency to be very important in every geographic market. Prysm provides regulators a proof point that one can make energy efficient displays without compromising quality or cost."

We will have some additional technical details in the article to be published in Insight Media’s Large Display Report.

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