| 摘要 |
<p>PURPOSE:To perform automatic focus detection by providing a transparent mold member whose front surface is made into a spherical surface with fine recessed or projection parts where a pattern with contrast is projected and a projection lens arranged in front of the mold member. CONSTITUTION:The projection parts 38 and 40 are formed on the surface of the lens part 36a of the transparent resin mold in a spherical lens shape which faces the projection lens, and the projection parts 38 and 40 are thin and long at right angles to the paper surface crossing the optical axis 36X at right angles while made symmetrically about a plane perpendicular to the paper surface. Further, the breadthwise direction of those projection parts 38 and 40 coincides with the array direction of many photosensors of a CCD line sensor. The angle of total reflecting parts 38a and 40b is set to the angle at which a light beam L3 is reflected totally, and then the light beam is all reflected totally, so there is no light projected from the total reflecting parts, thereby projecting a contrast pattern on a focus detection area. Consequently, even when the contrast of a subject is low, precise focus detection is carried out while the contrast is increased.</p> |
