Abstract: Embodiments described herein relate to an apparatus that includes a stepper motor, a driver chip communicatively coupled to the stepper motor, an encoder communicatively coupled to the stepper motor, and a feedback controller communicatively coupled to the driver chip and the encoder. In an embodiment, the feedback controller includes a state space plant configured to receive a control signal and generate a vector including a position and velocity of the stepper motor. In an embodiment, the feedback controller further includes a pulse width modulation (PWM) converter configured to receive the vector and output a first PWM signal corresponding to a number of steps to drive the stepper motor and a second PWM signal corresponding to a direction of the number of steps of the stepper motor. In an embodiment, the feedback controller further includes a Luenberger observer configured to receive a feedback signal from the encoder.

Abstract: The present invention relates to novel thiosilicate phosphor compositions. The invention is further a physical vapour deposition method for the deposition of rare earth activated thiosilicate phosphor compositions comprising providing at least one or more source materials where the source materials may comprise a barium silicon alloy, an intermetallic barium silicon compound, a protected barium metal and combinations thereof; providing an activator species; and effecting deposition of the one or more source materials and activator species as a thin film phosphor composition on a selected substrate. The method allows for the deposition of blue thin film electroluminescent phosphors with high luminance and colors required for TV applications.

Abstract: The present invention is a method for gettering undesirable atomic species from a vaporizing atmosphere during deposition of multi-element thin film phosphor compositions. The method comprises vaporizing one or more getter species immediately prior and/or simultaneously during the deposition of a phosphor film composition within a deposition chamber. The method improves the luminance and emission spectrum of phosphor materials used for full colour ac electroluminescent displays employing thick film dielectric layers with a high dielectric constant.