| 摘要 |
<p>The speculum has a pair of pivoted blades (1,2) with the inside face of one being equipped with a light source. This may be in the form of an electric bulb (3) or an optical fibre using a ray of monochromatic light e.g. a lower beam. In the first case, the bulb may be powered by a battery (5) mounted within the proximal part of the blade or in an external cartridge attached to the handle of the speculum. The electric circuit is closed to illuminate the examination sight when the screw (7) controlling the opening of the blades contacts an interrupter (13) associated with the battery.</p> |
