Optical Characteristics of an Ultrasound Gel Lens

Conventional camera modules are characterized by a substantial size, thickness, and weight. This is a consequence of the need for multiple lens elements to achieve the required level of image quality. However, as portable electronic devices continue to undergo miniaturization, there is a growing demand for smaller and thinner camera modules. In this paper, the optical characteristics of an ultrasound gel lens were evaluated quantitatively by expanding the wavefront of the transmitted light in terms of the Zernike polynomial. It was possible to control the focal length of the lens by changing its surface profile through the acoustic radiation force generated by ultrasonic vibration. The effects of ultrasound excitation on spherical aberration, coma aberrations, and astigmatisms were investigated. It was observed that spherical and coma aberrations increased with voltage amplitude, while astigmatism exhibited a reduction in magnitude.