| 摘要 |
PURPOSE:To prevent an optical system from being complicated and to easily make a projected image in a focused state by introducing non-visible light to an least a part of a projection system so that a specified surface is irradiated with the light and using reflected light therefrom so that a distance to the specified surface may be detected. CONSTITUTION:As to the flux of infrared rays from a light emitting element 17, only S-polarized component is reflected by a polarizing beam splitter 12 an projected by a projecting lens 18 to an object 19. A part of the flux of the reflected light enters an infrared-ray receiving lens 20 and an image-formation sot is formed on a bisectional sensor 21. Since the position of the spot differs in accordance with the position of the substance to be projected 19, the sensor 21 is moved to a focusing position where the respective sensor outputs in two divisions of the sensor 21 are made equal by a controller and detects the distance state from the object. According to the detected result, the lens 18 is moved to make the projected image in the focused state. Even though the same projection system as in the case of visible light is used, the projected image is not influenced because the light is infrared rays. |
