1. Field of the Invention
The present invention relates to a photographing lens system, and more particularly, to a compact photographing lens system used in a mobile phone camera.
2. Description of the Prior Art
In recent years, with the popularity of mobile phone cameras, the demand for compact imaging lenses is increasing, and the sensor of a general photographing camera is none other than CCD (charge coupled device) or CMOS (Complementary Metal-Oxide Semiconductor Sensor). Furthermore, as advanced semiconductor manufacturing technology has allowed the pixel size of sensors to be reduced and electronic devices have become more compact and powerful, there is an increasing demand for compact imaging lenses featuring better image quality.
A conventional compact imaging lens generally comprises two lens elements so as to reduce the production cost. As the two-element lens has limited capability to correct aberrations, it became insufficient for a high-end photographing module. However, employing excess number of lens elements will make it difficult to reduce the total track length of the lens.
To obtain good image quality and maintain a compact form, a photographing lens system comprising three lens elements is a feasible solution. U.S. Pat. No. 6,490,102 discloses a triplet lens system wherein the third lens is a spherical glass lens. The employment of spherical lens reduces the system's freedom in correcting the off-axis aberrations, making it more difficult to control the image quality.
Therefore, a need exists in the art for a photographing lens system that features better image quality, maintains a moderate total track length and is applicable to compact portable electronic products.
USPTO Backgrounds
USPTO Backgrounds