Prysm Inc’s new class of display Laser Phosphor Display (LPD) has gained attention primarily for energy consumption up to an enormous 75% less than other display technologies. Low power consumption is particularly significant for this display technology as it is currently aimed at larger format display applications. Having the wide viewing angle of plasma (another emissive display) combined with very low power consumption (definitely not a characteristic of plasma displays) makes LPD perfect for large scale public signage and advertising.

How LDP Works

Solid state laser diodes (similar to those used in optical storage drives) generate a fan-shaped array of modulated laser beans that compose the image on the screen. To target all the pixels on the display the laser beams are reflected by mirrors to create the required number of lines for the vertical resolution. In a manner similar to local dimming with LED LCD diodes, the lasers are varied in intensity between fully off to fully on to define the pixels across each horizontal line. As with local dimming, this boosts black levels, contrast ratios and energy efficiency. However, as there isn’t the heavy light filtering of LCD technology, the energy efficiency capture is much higher.

An LPD display reproduces colors through the combination of red, green and blue emitting phosphors arrayed over the surface of the display. The lasers are modulated to the correct energy level to trigger the correct combination of light from the RGB phosphors making up each pixel. As with plasma displays, LPD displays have an anti-glare coating to reduce reflections and improved visibility.

LPD sounding somewhat like a CRT display is understandable however, there are crucial differences. Lasers are used instead of electron beams and laser accuracy, necessary to target individual pixels on the display, is ensured by position feedback from each laser scan. The self calibration of the laser beams is a unique achievement.

Low Power

Prysm state that an LDP display consumes about 100W per square meter of display area while producing a luminance of several hundred nits. The brightness is a bit lower than the common 400 to 500 nits for contemporary displays. Prysm have rightly pointed out the lower running temperatures and associated cooling costs which accompany its display technology.

Wide Viewing Angle

LDP diplay technology shares the wide viewing angle of emissive displays which combined with low power consumption makes it an excellent public display solution.

Fast Refresh Rate (240Hz)

LDP displays refresh at a rate of 240Hz which matches the fastest available with LCD technology at the moment. Consequently, fast on-screen motion is kept sharp (an anti-blur characteristic). A 240Hz refresh rate is also fast enough for displaying 3D content.

High Resolution

LDP displays are capable of HD resolutions.

Eco Friendly

Prysm state’s that it’s LPD displays are made with low impact manufacturing processes and non-toxic materials.

Long Lasting

With the use of long-life semiconductor lasers combined with a self-calibrating feedback architecture LDP displays are designed to deliver a long life.

Free Form

Prysm empasises in it’s literature that LPD enables displays of any shape, size and resolution can be built sometimes through the combination of standard sub-units.

HDTV Future for LDP?

LDP displays have a lot of desirable characteristics for use in HDTVs however, Prysm have not addressed this application yet. The only technology barrier at the moment seems to be the larger depth requirements compared to the almost razor thin LCD and plasma displays available at the moment. The depth of an LDP display is about one tenth of the diagonal screen size for example, 5 inches deep for a 50 inch display. Given how rapidly LCD and plasma displays have shrunk in recent years this doesn’t seem an insurmountable problem.