Optical lens and display device

An optical lens, adapted to receive an image beam from an imaging element and sequentially comprising a first lens, a second lens, a third lens, and a fourth lens respectively with a refracting power along an optical axis from a light incidence side to a light exit side, wherein each of the first lens, the second lens, the third lens, and the fourth lens respectively comprises a light incidence surface and a light exit surface, the light incidence surface of each of the first lens, the second lens, the third lens, and the fourth lens faces the light incidence side and allows the image beam to pass therethrough, and the light exit surface of each of the first lens, the second lens, the third lens, and the fourth lens faces the light exit side and allows the image beam to pass therethrough, wherein

• the refracting power of the first lens is positive,
• the refracting power of the second lens is negative,
• the refracting power of the third lens is positive,
• the first lens or the third lens is made of glass,
• the optical lens receives the image beam from the light incidence side, the image beam forms a stop on the light exit side, and the image beam forms a minimum beam cross-section at a location of the stop,
• wherein three of the first lens, the second lens, the third lens, and the fourth lens are plastic aspheric lens, and the other is a glass aspheric lens.