| 摘要 |
<p>PURPOSE: An optical system is provided to reduce a size by decreasing a total distance. CONSTITUTION: A small optical system includes a first lens(10), an aperture, a second lens(20), a third lens(30), a forth lens(40), a fifth lens(50), a filter(60), and an optical reception device(70) from an object side to an image side. The first lens, the second lens, and the forth lens have positive refractive power. The third lens and the fifth lens have negative refraction power. The forth lens has a meniscus shape. The fifth lens includes at least one non-spherical deflection point. The filter consists of an IR cut-off filter.</p> |
