Abstract: A coupled lens structure for a mixed/augmented reality system includes: a lens tube; a first lens with a first aspherical light input surface coupled to a lens-tube light input surface; a second lens with a second spherical light input surface optically coupled to a first spherical light output surface of the first lens; a third lens with a third spherical light input surface optically coupled to a second aspherical light output surface of the second lens; and a fourth lens with a fourth spherical light input surface optically coupled to a third spherical light output surface of the third lens and a fourth spherical light output surface coupled to a lens-tube light output surface. The coupled lens structure has volume of 2.1-3 cc, a lens-tube outer diameter of 12-13.5 mm, and a full angle of view not greater than 30 degrees, featuring an effective reduction in volume and weight.