A laser pointer or laser pen is a small handheld device with a power source (usually a battery) and a laser diode emitting a very narrow coherent low-powered laser beam of visible light, intended to be used to highlight something of interest by illuminating it with a small bright spot of colored light.50mW Laser Pointers Power is restricted in most jurisdictions not to exceed 5 mW.The small width of the beam and low power of typical laser pointers make the beam itself invisible in a reasonably clean atmosphere, only showing a point of light when striking an opaque surface.100mW puntero láser verde Some higher-powered laser pointers project a visible beam via scattering from dust particles or water droplets along the beam path. Higher-power and higher-frequency green or blue lasers may produce a beam visible even in clean air because of Rayleigh scattering from air molecules,3000mW Laser Pointer especially when viewed in moderately-to-dimly lit conditions. The intensity of such scattering increases when these beams are viewed from angles near the beam axis. Such pointers,ticularly in the green-light output range, ar used as astronomical-object pointers for teaching purposes.
|
ขณะนี้มีผู้เข้าใช้
ผู้เข้าชมในวันนี้
