Abstract: Provided are an image sensor module, a camera module including the image sensor module, and a method of correcting a back focal length of a camera including the camera module. The image sensor module includes an image sensor which converts light into an electrical signal; an infrared ray filter which is configured to be movable between a first position in an optical path of the light entering the image sensor and a second position outside the optical path of the light entering the image sensor, and decreases an amount of infrared rays entering the image sensor if the infrared ray filter is at the first position; and a variable focus liquid crystal lens which is disposed in the optical path.

Abstract: An optical (disc) driving system including the DLL based multiphase clock generator circuit capable of generating 32 different phases from input clock having a frequency of 800 MHz or greater. The multiphase clock generator includes on a delay locked loop (DLL) having a frequency divider for outputting an N-divided clock to a first set of M voltage-controlled delay cells within a feedback loop, and further including an identical set of M voltage-controlled delay cells outside of the feedback loop for delaying the undivided clock and for outputting M multiphase clocks. An optical driver circuit of an optical driving system and a method for implementing a write-strategy for preventing “overlapping” of marks written on adjacent grooves on an optical disc. The circuit and method produce multiple write-strategy waveforms (channels) switching at a high resolution (e.g., T/32) in the Gigahertz frequency range.