| ??? 05/02/09 17:32 Read: times |
#165011 - Per, I think you've lost your way Responding to: ???'s previous message |
Per Westermark said:
Richard Erlacher said:
Now ... let's review ... the laser produces a pixel. It doesn't produce a line or any shape. No, a laser does not produce a pixel. It does produce a ray. It isn't until you sweep the ray while modulating the beam that you get pixels, as the term pixel is normally used. The thing here is that pixel (picture element) isn't really defined other than for raster displays. Well, the "ray" from a Cathode Ray Tube produces a ray, too. On a long-persistence phosphor, a stroked display works, but not when one projects the ray onto a wall. There, it produces an illuminated spot (pixel) wherever it strikes the wall. I verified that with my hand-held laser pointer, which, BTW, produces a very visible spot at 50 meters. I routinely use it to point out which branches of my trees are to be removed in bright daylight (The tree service doesn't work at night). In suppressed lighting, where Chico says he intends to use his device, it is clearly visible at 100 meters. How long do you expect the light to persist? How fast can you repeat the entire drawing when moving the mirror with a voice coil? I don't doubt for even a moment that it can be done with a simple drawing. However, the spinning mirror as part of a rasterized display is MUCH easier to implement. Further, it can be made to work just fine with a 12 MHz or even 8 MHz 805x. RE |
