| 摘要 |
PURPOSE:To eliminate the uneven quantity of light in the slit part of a lamp in a slit illumination device for a copying machine, etc. by constituting the slit part of the lamp in such a way that diffusion transmission takes place in the pipe wall part in the slit part of the lamp and perfect reflection takes place on the opposite side. CONSTITUTION:A glass tube part 14a opposing to a slit part is subjected to a diffusion transmission treatment. The image of a filament 13 increases apparently its size and the apparent length in a light emitting part 13F increases, resulting in decreased uneven quantity of light in the longitudinal direction in the slit part. A glass tube part 14b is subjected to a perfect reflection treatment, and the mirror image of the part 13F is formed near the part 14b. The secondary light source generated by a specular surface is a light source having a substantially high luminous intensity. The luminous flux thereof passes the part of a non- emitting part 13E and arrives at the slit part, whereby the uneven quantity of light is decreased. It is possible to prevent the unevenness in the quantity of irradiation light in the slit part even if the device is made compact by decreasing the distance between the lamp and the slit part. |
