1. A camera module, comprising: a lens group; an image sensor; and a liquid crystal module disposed between the lens group and the image sensor, the liquid crystal module comprising a first glass substrate adjacent to the image sensor, an opposite second glass substrate, a plurality of liquid crystal molecules arranged between the first glass substrate and the second glass substrate, a first transparent electrode layer formed on the first glass substrate and facing the liquid crystal molecules, and a second transparent electrode layer formed on the second glass substrate and facing the liquid crystal molecules, the liquid crystal molecules being configured for adjusting a light path of the light transmitting therethrough in response to an electric field between the first and second transparent electrode layers, thus adjusting a depth of field of the camera module, each of the first transparent electrode layer and the second transparent electrode layer comprising a circular electrode, a first ring-shaped electrode, a second ring-shaped electrode, a third ring-shaped electrode, and a fourth ring-shaped electrode, the circular electrode, the first ring-shaped electrode, the second ring-shaped electrode, the third ring-shaped electrode, and the fourth ring-shaped electrode being concentrically arranged in sequence from the center of the first glass substrate to the periphery of the first glass substrate, with an air gap maintained between each two adjacent electrodes, and a diameter of the circular electrode and corresponding transverse widths of the first ring-shaped electrode, the second ring-shaped electrode, the third ring-shaped electrode, and the fourth ring-shaped electrode being in a relationship of d 1 >d 2 >d 3 >d 4 >d 5 , wherein d 1 represents the diameter of the circular electrode, and d 2 , d 3 , d 4 , and d 5 represent the transverse widths of the first ring-shaped electrode, the second ring-shaped electrode, the third ring-shaped electrode, and the fourth ring-shaped electrode, respectively.