<title>Characterization of a digital micromirror device for use as an optical mask in imaging and spectroscopy</title>

Abstract

The digital micromirror device (DMD) is a micro-optical-electro-mechanical structure (MOEMS) consisting of an array of 16.tm x l6jtm square mirrors positioned on a 17 jim pitch. Each individual mirror can be tilted +1-10 degrees relative to the DMD substrate; the tilt is along the diagonal direction of the micromirror. The device was invented and manufactured by Texas Instruments (TI), Inc. TI packages the DMD as an OEM product for use in projection displays. We are investigating the use of the DMD as a spatial light modulator for precision imaging and spectroscopy applications. This includes optical characterization of the device, as well as systems engineering to operate the device. Some of the performance metrics to be considered are the diffraction efficiency, optical-switching contrast, background scattering properties, mirror crosstalk, and the modulation transfer function (MTF). DIGITAL MICROMIRROR DEVICESAt the RIT Center for Imaging Science, our research involves the development and implementation of innovative imaging instrumentation for use in astronomical imaging and spectroscopy. The goal of this characterization effort is to understand the performance limits of DMD devices for use in precision imaging instrumentation. We are particularly interested in understanding the scattering properties, the diffraction efficiency, and the MTF. With this information we intend to develop a set of design rules for incorporating a DMD device into an optical imaging chain. DMD architectureThe Digital Micromirror Device (DMD) was developed by Texas Instruments (TI), and is the first large-scale commercial implementation of a micro-optical-electro-mechanical system (MOEMS)1'2. The device consists of an array of micromirrors, 16j.tm x l6jim square, mounted on a 17 im pitch. Each mirror is mounted on a post, and can tilt along the diagonal direction. The mirror is tilted by electrostatic attraction towards biased landing pad/electrodes under the mirror. These landing pads constrain the mirror to fixed rotation angles of +1-10 degrees relative to the substrate. The mirror assemblies are mounted atop a CMOS circuit which is used to latch the input mirror state. The device is marketed by TI as an OEM board set for use in projection display devices. The complete DMD and board set are termed, by TI, a Digital Light Processor (DLP) . The DLP consists of a 640 x 480 pixel DMD (VGA format; an SVGA format is also now available) mounted on a driver/formatter board, and also includes the required PC interface boards. Reports in the trade press suggest that a DMD configured for use in digital printers and film writers is also forthcoming3'4. TI also makes the DLP available in kit form for use in research applications. In accordance with current usage, we will use the acronym DMD in this paper to mean the entire board set as well as the DMD proper.Author contact information -kjk5423 @ritvax.rit.edu SPIE Vol. 3292 • 0277-786X/98/$1O.OO Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/14/2015 Terms of Use: http://spie...

A Survey of Signal Processing Problems and Tools in Holographic Three-Dimensional Television

“…Specific solutions of the wave equation for different purposes may be adopted to solve the 3DTV display related problems [112], [119]- [121], [70], [122], [111], [123]- [130], [113]. Interesting solutions provided for some other related cases, that might be applicable also to the holographic 3DTV problems, can be found in the literature [131]- [141].…”

Programmable Imaging: Towards a Flexible Camera

“…For instance, in Malbet et al (1995) the DMD is used to mask out bright sources of light (like the sun) so that dimmer regions (the corona of the sun) can be imaged with higher dynamic range. In Kearney and Ninkov (1998), a DMD is used to mask out everything except a small number of stars. Light from these unmasked stars are directed towards a spectroscope to measure the spectral characteristics of the stars.…”

Programmable Point-source Digital In-line Holography Using Digital Micro-mirror Devices

“…Early application of the DMD is in projection systems but several emerging applications have evolved and these include confocal microscopy, high dynamic range imaging, 3D metrology and holography [ABD09,BPS03,DM99]. Applications of DMD in off-axis digital holographic recording and reconstruction have been demonstrated [DDS03,KN98]. In DIHM with a programmed point-source, the scanning of the spatial location of the point source was achieved by using the DMD as the primary source of the spherical reference field that illuminates the object.…”