Tilt compensated MOEMS projector as input device

Abstract

Silicon micro machining once headed into two directions: MEMS (micro electro mechanical systems) based sensors like accelerometers and gyroscopes on the one hand, MOEMS (micro opto electro mechanical systems) based actuators like scanner mirrors on the other hand. Now both directions meet again: A tilt compensated projector module uses a two dimensional excited scanner mirror as well as accelerometers and gyroscopes. The projector module can have a minimum size of 30 x 15 x 15 mm³ with a monochrome red laser source (λ = 635 nm). It reaches a resolution of 640 x 480 pixels (VGA) and a frame rate of 50fps. Colour projection requires lager size due to the lack of compact green laser sources. The tilt and roll angles are measured statically by a three axes accelerometer, fast movement is detected dynamically by three single axis gyroscopes. Thus tilt of the projection systems was compensated successfully. The dynamic range was set to 300 x 300 pixels for sufficient system dynamic. Furthermore the motion detection was used to achieve control and input device functions. The first demonstration and test system consists of a projector mounted at the axis of a PC racing wheel together with the additional inertial measurement unit (IMU) system. It was shown that projection and input function work well together. Using this approach, new possibilities for hand-held devices arise in the close future.