Next app for TI's DLP is large touchscreens

DALLAS – Digital light processor technology developed by Texas Instruments 25 years ago has been used to bring big-screen cinema to the digital age is now being used in picoprojectors for smartphones, cameras and tablets, company officials said. By this time next year, they predict DLP technology will powering large touchscreens.

DLPs are based on micron-sized mirrors that turn a pixel on or off by deflecting light either to the screen or off to one side at a rate of 10,000 times per second. The technique enable a wide array of projection applications like 3-D TV along with metrology, spectroscopy, medical diagnosis, industrial inspection and other applications. Now TI is targeting large touchscreens.

A few startups are adapting scanning lasers for picoprojector applications, but TI counters that it has already developed MEMS scanning lasers for printing applications, and the company insists that DLP works better.

"TI is agnostic with regard to the source of illuminations [since] we can support lamps, LEDs, lasers, whatever," said Kent Novak, TI’s senior vice president for DLP. "Our patent portfolio for DLP is already deep, and we are making a concerted effort to expand it further into new application areas."

TI's support of skunk works was the original inspiration for the DLP, when DLP inventor Larry Hornbeck, now a TI Fellow, was experimenting with analog deformable mirrors. After leading TI’s DLP group, Hornbeck sought to instill entrepreneurial spirit into TI's young engineers, encouraging them to start similar skunk work projects. One resulted in TI's interactive projector.

"Larry told us that we had to act like a startup to keep TI ahead of the competition," said Marshall Capps, a TI systems software engineer and inventor of the interactive projector. "He was very supportive of my skunk works interactive projector project, which is now offered as an option by many projector makers using DLP."

Capps found that by projecting a grid of lines between frames at a high rate that a small wireless pen could be used to sense where it was pointing on the screen. Software can then interpret the pen's location like a 3-D mouse, with buttons allowing presenters to interact with applications being projected on the screen. Most DLP projectors can be controlled with the addition of an inexpensive wireless interactive pen.

TI's is also turning DLP rear projectors into interactive touchscreens. By illuminating the backside of the screen with an infrared LED, a small camera can sense when a finger touches the screen. "The infrared just goes right through the screen, except where a finger is touching it, which shows up as a bright spot that is invisible to the naked eye," said Capps.

Computer vision algorithms can then be used to interpret the bright spots as taps, swipes and other gestures that are ordinarily associated with a conventional touchscreen. The advantage of the DLP touchscreen, TI argues, is that any number of fingers can be sensed with no additional hardware.

TI is currently showing a prototype to auto manufacturers as an ultra-inexpensive alternative to dashboard touchscreens. The demo shows an entire center console turned into an interactive touchscreen with no size limit. Dashboards or wall kiosks could be made into a DLP touchscreen. TI said the first applications will begin appearing in 2013.