A miniature projecting system for portable devices

摘要

A miniature projecting system with dimension of 20 mm in length, 12 mm in width, and 10 mm in height suitable for mobile devices is presented in this paper. This novel projecting system consists of an optical system with two lenses, a liquid crystal display (LCD) device, a collimating tube, and a 1 W high power light-emitting diode (LED) with wavelength of 525 nm. It projects a clear and bright image of 4.5 cm×1.3 cm which displays 24 digits onto the palm at a distance of 20 cm in a room with light on. The projector can be fabricated easily at low cost. Miniaturization is achieved in this system so that it can be equipped into thin mobile phones.