| 摘要 |
The portable light source (10) has an electro-luminescent diode (11) emitting a beam of light, a support (12) and connection for the diode, and an optical screen (15) which can be moved in front of the diode to vary the angle of divergence of the beam. The optical device carries a one or more Fresnel lenses (16) mounted on a plate (17) which can be moved over the front of the diodes. |
