Lens and fabrication method thereof

A lens assembly, comprising in order from the image magnification side to the image reduction side:

• a first lens, a second lens, a third lens, a fourth lens and a fifth lens in the lens assembly, wherein the second lens to the fifth lens are aspheric lenses;
• the lens assembly includes less than 9 lenses with refractive power,
• the field of view (FOV) is between 180° and 220°;
• LT is the length on the optical axis of the lens from the lens surface farthest from an imaging plane of the lens assembly to the lens surface closest to the imaging plane of the lens assembly;
• IMH is ½ of the length of the image circle on the imaging plane;
• the lens assembly satisfies the condition of 3.5<LT/IMH<6;
• an intersection of a first focal plane with an optical path of the lens assembly is referred as a first intersection, and the first focal plane is the focal point at wavelength of 555 nm of the lens assembly;
• an intersection of a second focal plane with an optical path of the lens assembly is referred as a second intersection, and the second focal plane is the focal point at wavelength of 850 nm of the lens assembly;
• a distance from the second intersection to the first intersection is less than 20 μm.