Laser-material interaction through digital light processing

• Main Author: Liau, Wi Zardson.
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering::Assistive technology
• Online Access: http://hdl.handle.net/10356/53994
• Institution: Nanyang Technological University

DLP technology is based on an optical semiconductor, called a Digital Micromirror Device (DMD), which uses mirrors made of aluminium to reflect light to make a picture. The DMD is often referred to as the DLP chip. The chip can contain more than 2 million tiny mirrors, about the size of a typical pixel in our smart phones today. The mirrors are laid out in a matrix, with each mirror representing one pixel. It was invented by Dr. Larry Homback and Dr William E. “Ed” Nelson of Texas Instruments (TI) in 1987 [1]. However, the application of DMD among industries is still minor. In this research, the DMD will be a part of a Digital Light Processing (DLP) system, combined with a laser to do controlled laser interaction onto our material of choice, which we will analyse for a suitable one. We made this combination of DLP and laser interaction as a search through the database yield no previous studies or experiment that combined laser interaction with DLP. Current laser interaction with material techniques are such that a laser beam reflects onto a single mirror and the mirror controls that single beam into a work piece. Another technique is where a single laser beam is shot directly onto a work piece and that work piece is moved in the x-y direction. Such techniques involve only 1 beam at a time which can be time consuming. By combining laser interaction with DLP, we can project the already final image directly onto the work piece in one shot, thus reducing the time taken to work on a work piece, increasing the throughput of the entire work. We first had to calculate the threshold power of all the equipment involved in the experiment to ensure that the DLP chip which laser beam would be reflected on would not be interactiond yet at the same time, finding a material with laser interaction threshold low enough so that some form of engraving or interaction is done onto the final workpiece to be used for successful laser interaction. The important parameter for the material properties which determines if it is able to go through laser interaction is its optical properties, optical absorptivity, reflectivity, wavelength of light, penetration depth, interaction time, diffusion length and laser interaction threshold.