Slashdot Mirror
Forget LCDs and LEDs, Here Come LPDs
waderoush writes "It's not every day you hear about a brand new display technology, but San Jose, CA-based Prysm came out of stealth mode yesterday to talk about its plans for manufacturing laser phosphor displays, or LPDs. The new devices, which the company will show off at the Integrated Systems Europe trade show in Amsterdam next month, reportedly use 25 percent as much electricity as equivalently-sized LCD screens. And they should be easier to manufacture too, since they don't have a backplane of transistors like LCD screens: the image is generated by a laser beam that sweeps across phosphor stripes under the control of a scanning mirror. The venture-funded startup, which plans to build and sell LPD screens under its own brand, is promoting them as a low-cost, low-maintenance way to display information in lobbies, airports, broadcast studios, command centers, and the like."
How is this better than Mitsubishi's LaserVue technology? It's basically a laser DLP to phosphor opposed to whatever material is used by Mitsubishi for a standard DLP screen. It even looks like the LaserVue uses less power than this.
"A person is smart. People are dumb, panicky dangerous animals and you know it." - K
It has to be far enough back to reach all edges.
No, it just has to have some mirror arrangement that allows it to reach the whole screen. I don't see any reason why the laser has to strike the phosphor at anything close to a perpendicular alignment.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
I don't see any reason why the laser has to strike the phosphor at anything close to a perpendicular alignment.
The angle at which the beam strikes the phosphor would determine the shape of the intersecting region, which may be difficult to correct for. However, a small mirror near each "pixel" that redirected the beam straight at the phosphor would likely correct the situation without taking up too much extra space.
You must wait a little bit before using this resource; please try again later.
guaranteed to be thicker than LED or LCD, and with phosphor delay; I want LED so that I can have [effectively] instant transitions. we can get back the delay effect with processing, but you can't eliminate phosphor delays when you've got phosphors.
There is essentially zero phosphor delay (I defy you to measure it ... I am a visual neuroscientist and have, so yes, it is possible, and no, it is not easy) on the scale of perceptual latencies. I believe the latency from excitation to phosphor emission is on the nanosecond scale. The typical perceptual delays in the early visual system (retina and the first few stages of processing in the brain) are on order of 30 milliseconds, going from the time photons enter the eye to the first wave of activity in primary visual cortex. Different orders of magnitude. Like 6. Phosphor delay is irrelevant.
What you are perhaps thinking of is the phosphor DECAY which is another thing entirely. When phosphors are excited (such as by an impinging electron or photon beam) the emitted brightness steps up almost instantaneously and then decays down through an exponential relaxation curve. That decay time can tend to blur images when too long, or induce eye bleed (to use the vernacular) when the update rate is too low. The thing is that phosphor decays can be adjusted by reformulating the compounds, and are determined ultimately at time of manufacturing. Very fast phosphors are available to support KHz updates, but also very slow ones (some older oscilloscopes have phosphor decay constants measured in seconds).
Contemporary LCD monitors have typically 2 or 3 frames of latency because of the push to get faster transition times. Those 5 ms response time LCDs get fast specs by overdriving the pixels in a highly controlled fashion, but one that requires knowing what is on the next handful of frames. Since we live in a causal world, that means introducing a 2-3 frame latency for processing within the display. Since the update rates on LCDs are typically 60 Hz, that's on order of 45 ms latency, a non-trivial fraction of the loop from visual perception to motor action (known in the gaming vernacular as twitch response). If you're watching a movie, that latency is irrelevant and wholly, entirely unperceived. If you're playing a game, then it is very important.
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.