Patent attributes
A two-piece infrared single wavelength projection lens system includes, in order from an image side to an image source side: a first lens element with a positive refractive power having an image-side surface being convex near an optical axis and an image source-side surface being concave near the optical axis, at least one of the image-side and the image source-side surfaces of the first lens element being aspheric; a second lens element with a positive refractive power having an image-side surface being concave near the optical axis and an image source-side surface being convex near the optical axis, at least one of the image-side and the image source-side surfaces of the second lens element being aspheric; and a stop disposed before the image source-side surface of the first lens element or between the image source-side surface of the first lens element and an image-side surface of the second lens element.
