Imaging optical system

Abstract

The invention discloses an imaging optical system. From the object side to the image side, the imaging optical system sequentially comprises a first lens with positive refracting power and a convex front surface, an aperture, a second lens with negative refracting power, a third lens with a convex front surface, and a fourth lens with negative refracting power and a concave front surface, whereinan aspheric surface and an inflection point are arranged on the rear surface of the fourth lens. The distance on an optical axis from the rear surface of the fourth lens to an imaging surface is BFL,the total optical length of the imaging optical system is TTL, and the relationship between BFL and TTL is that BFL / TTL is larger than 0.12. As four lenses with refracting power are arranged in the imaging optical system, the structure and arrangement of the lenses can effectively reduce the volume of the group of lenses, lower the sensitivity of the optical system and even achieve high image resolving power at the same time.

Description

technical field [0001] The invention relates to an optical system, in particular to an imaging optical system applied to a camera phone. Background technique [0002] In recent years, with the rise of mobile phone cameras, the demand for miniaturized photographic lenses has been increasing, and the photosensitive components of general photographic lenses are nothing more than charge coupled devices (Charge Coupled Device, CCD) or complementary metal oxide semiconductors (Complementary Metal- OxideSemiconductor, CMOS), and due to the advancement of semiconductor process technology, the pixel area of ​​the photosensitive component is reduced, and the miniaturized photographic lens is gradually developing into the high-pixel field. Therefore, the requirements for imaging quality are also increasing. [0003] Common high-resolution mobile phone lenses mostly use a front aperture and a four-piece lens group. Among them, the first lens and the second lens are often bonded with two...

AI Technical Summary

Problems solved by technology

[0003] Common high-resolution mobile phone lenses mostly use a front aperture and a four-piece lens group. Among them, the first lens and the second lens are often bonded with two glass spherical mirrors to form a Doublet to eliminate chromatic aberration, such as US 7,365,920 As shown, but this method has its disadvantages. First, too many spherical mirror configurations lead to insufficient system freedom, which makes it difficult to shorten the overall length of the optical system. Second, the bonding process of glass lenses is not easy, resulting in difficulties in manufacturing.

US 7,277,238 is a lens group of four independent lenses, including a plurality of aspheric lenses, which can effectively shorten the total optical length of the optical system and obtain good imaging quality, but because its aperture is set before the first lens, it will make the system The sensitivity is also relatively increased, and it is more difficult to control the yield in manufacturing

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