Week 2-3

  Progress Made:

In week 2 and 3, I mainly completed two tasks which are FYP presentation and FYP specification form respectively. I just did some further research about some general ideas about my FYP, for instance, the principle of DMD.

Figure 1 shows a schematic of 2 DMD mirror pixels.

Every mirror is put on a yoke that is linked to 2 support posts by compliant torsion hinges. For this kind of hinge, the axle is fixed at two ends and twists in the middle. Then according to electrostatic attraction, the positions of the mirrors are controlled by two pairs of electrodes. Most of time, equal bias charges are applied to these two electrodes at the same time. Hence, the mirror will keep its position. However, if you want to move this mirror, you can load the required state to the SRAM (static random array memory) cell which is under the mirrors. When all the SRAM have been loaded, the bias voltage will be removed and the mirror can rotate. Nevertheless, if you still want to stable the mirror, you can restore the bias voltage.

Figure 2 displays how DMD display system work. There are two micromirrors in this figure. Each micromirror is able to rotate +12  or -12  to an on or off state. This on or off state is determined by the binary state of SRAM cell which is under each mirror. In on state, the light from the lamp can be reflected into the projection lens, making the pixels bright on the screen. However, in off state, the light is directed elsewhere making the pixels dark.

I did not do some reading about the details about DLP LightCrafter components, which is in my plan in the last week. The reason is that I misunderstand my jobs in the FYP. What I should focus on in my FYP is to learn how to use this equipment rather than study the configuration of it.

  Problems and Challenges:

By now, I do not have a clear understanding of my FYP. I do not know the deep knowledge of both DMD technology and DLP LightCrafter. What is worse is that I do not have a distinct idea about my final prototype of DMD display systems for clinical eye testing. Hence, these are several serious problems and challenges I meet at present. I have to figure out these as soon as possible.

  Plans for Next Week:

l  Establish a blog and record my progress

l  Search some materials on IEEE about DLP technology, DMD technology and DLP LightCrafter

l  Read the principle, advantages and application of  DLP and DMD technology

l  Read alternative projection techniques, like LCD

Reference:

1, Dana Dudley, Walter Duncan, John Slaughter, Emerging Digital Micromirror Device (DMD) Applications, http://www.loreti.it/Download/PDF/DMD/paper_dmd.pdf