| 摘要 |
PURPOSE:To obtain an overhead projector which can automatically focus even if the height of an original surface is changed by distinguishing between the use of an additional device and the use of the original surface of a main body, and then automatically focusing. CONSTITUTION:The title automatic focusing projector is provided with a changeover switch 74 which switches a normal automatic focusing operation to match an original surface 6 of a main body 2 in order to place an original 7 and an automatic forcusing operation to match the original surface 7 of an additional device 70 mounted on the main body 2 instead of the original 7. When an exclusive liquid crystal original plane device 70 instead of the original 7 is placed on the original surface 6, the changeover switch 74 applies on-signal to a control arithmetic part. A correction coefficient (d), stored in a correction coefficient storage part, is inputted to the control arithmetic part; a projecting lens 10 moves by the instructed specified amount along the direction of an optical axis, and ultimately automatic focusing is completed. Therefore, automatic focusing is always ensured even if the height of the original surface is changed, and one automatic focusing projector can be used for many different purposes. |
