Patent attributes
An image forming lens has a configuration that an image forming lens IL for receiving parallel beams of light emitted from an observation target object and emerging from an infinity-designed objective lens of a microscope and forming an image of the observation target object in a predetermined position, is constructed of, in order from an object side, a first lens group G1 having positive refractive power and a second lens group G2 having negative refractive power, and the first lens group is constructed of a positive lens (e.g., a biconvex lens L1) and a negative lens (e.g., a negative meniscus lens L2). Glass materials of the positive lens and the negative lens configuring the first lens group G1 satisfy conditions of predetermined νdht and partial dispersion ratio Pht, then a transmittance, with respect to the light having a wavelength of 340 nm, of each of the glass materials of all the lenses is equal to or larger than 50% per glass thickness of 10 mm, and the transmittance with respect to the light having the wavelength of 360 nm is equal to or larger than 80% per glass thickness of 10 mm.
