OPTICAL DEVICE FOR ELECTRONIC VIEWFINDER

摘要

PURPOSE:To make a diopter adjustment and to reduce distortion by arranging a positive lens with large power and a positive lens with small power successively from an object side, making the 1st positive lens movable in the optical- axis directions, and using an aspherical surface as at least one surface of the lens system. CONSTITUTION:A picture on a CRT2 is enlarged through the optical device consisting of the 1st positive lens 2 and the 2nd positive lens 6 to be observed by the eye 4. The diopter adjustment is made by moving the 1st positive lens 5 on the optical axis to left and right. The 2nd positive lens 6 has an aspherical surface as at least one surface. When previously recorded information is observed while the 2nd positive lens 6 is removed from on the optical axis, the 1st positive lens 5 and the 2nd positive lens 6 are each provided with an aspherical surface as one surface to obtain desired distortion characteristics.