US Patent 11073682 Optical lens set

An optical-lens-set includes a first lens element of a concave image-side surface near its optical-axis, a sixth lens element of negative refractive power and of a concave image-side surface near its optical-axis to go with a fifth lens element of a concave object-side surface near its optical-axis or with a seventh lens element of negative refractive power. The Abbe number υ1 of the first lens element, the Abbe number υ3 of the third lens element, the Abbe number υ4 of the fourth lens element, the Abbe number υ5 of the fifth lens element, the Abbe number υ6 of the sixth lens element and the Abbe number υ7 of the seventh lens element together satisfy 5≤5υ1−(υ3+υ4+υ5+υ6+υ7).