IMAGING LENS, ESPECIALLY OBTAINING SUFFICIENT BACK FOCUS

摘要

PURPOSE: An imaging lens is provided to obtain good image quality with short optical length and low cost by realizing whole lenses with plastic. CONSTITUTION: The imaging lens has the first lens(L1), an iris lens, the second lens(L2) and the third lens(L3). The first lens and the iris lens and the second lens and the third lens are arranged toward the top from an object. The first lens is a resin lens having a positive refractive index of meniscus type. The second lens is a resin lens having a positive refractive index of meniscus type. The third lens is a resin lens having a negative refractive index. Both sides of the first lens are aspheric, and both sides of the second lens are aspheric, and at least one side of the third lens is aspheric.