1. Field of the Invention
The instant disclosure relates to a liquid lens package structure, and more particularly to a variable focus liquid lens package structure.
2. Description of Related Art
Cameras, mobile phone cameras and 3D-image processing devices often utilize a zoom lens to automatically focus, enlarge or reduce an image, so as to obtain a desired image. Conventionally, a zoom lens has multiple lens groups. These lens groups move along an optical axis of the lens to thereby change the spaces among them and accordingly, the overall focal length of the lens without affecting the imaging distance thereof. However, this type of lens needs relatively long lens group movement distance, and the movement distances of the lens groups are not in a linear relationship. Therefore, the zoom lens has difficulties in the structural design and control precision thereof, and has high manufacturing cost that could not be easily lowered. Currently, a liquid lens or liquid crystal lens (LC lens) has been used to improve the movement distances of lens groups in order to obtain reduced camera size.
According to the general principle of liquid lens, the liquid lens includes a tunable liquid-filled lens and a solid lens. By changing the shape of the liquid-filled lens to be a biconvex lens or a biconcave lens, or by using filling media of different refractive indexes, it is able to tune the focal length of the lens and achieve the purpose of zooming. Or, by using the liquid crystal-filled lens and changing the refractive index of the liquid crystal with an applied electric field, an electrically tunable-focus LC lens can be realized.