| 摘要 |
PURPOSE:To control the quantity of the extension of a lens at a high speed by installing a light emitting element at a position equivalent to an image pickup surface, irradiating an object with spot light through an image pickup lens, and forming an image of its reflected light on the image pickup surface through the same lens. CONSTITUTION:Light from the light emitting element 6 at a position equivalent to a point on the lens optical axis of the image pickup surface 3 passes through an aperture 5 and is reflected partially by a half-mirror 4 to illuminate the object 1 through a part E off the center part of the image pickup lens 2. The reflected light from the object 1 forms an image on the image pickup surface 3 through the lens 2 and half-mirror 4. When the object 1 is at the position shown by a solid line, the image of the light source 6 is formed on the optical axis of the lens 2, so its reflected light forms the image on the lens optical axis of the center part of the image pickup surface 3. The light from the light source 6 is irradiated as spot light above the object when the object is positioned as shown by a dotted line 1' or below the object when the object is as shown by a dotted line 1'', and the center of the reflected light from the object is therefore incident on the lower part and upper part on the image pickup surface 3 respectively. |
