180 likes | 564 Views
Mirasol Displays. MAE 268 Erik Bettis Josh Saylor. Introduction. MEMS device developed by Qualcomm Low power display Uses ambient light as source Operation requires very low voltages Replacement for current LCD screens Cell phones and other small devices
E N D
Mirasol Displays MAE 268 Erik Bettis Josh Saylor
Introduction • MEMS device developed by Qualcomm • Low power display • Uses ambient light as source • Operation requires very low voltages • Replacement for current LCD screens • Cell phones and other small devices • Enhance viewability in direct light • Brightness of display increases as ambient light intensifies • Light reflection of up to 50% Erik Bettis
Current Products Hisense C108 Handset Inventec V112 Smartphone G-Core Mini Caddy Erik Bettis
Mirasol Technology • Interferometric Modulation (IMOD) • Low power consumption • Increased readability in direct light • Bistability • Hysteresis • Built in Memory • Pixels • Color Generation • Interference • Spatial Dithering Erik Bettis
Interfermetric Modulation(IMOD) • Enables reflective, direct view and flat panel displays • Refresh rates on the order of microseconds • Video-rate capable • Contrast Ratio: >15:1 • Reflectivity: ~ 50% • Wall Street Journal • Contrast Ratio: 4:1 • Reflectivity: ~ 60% Erik Bettis
Interference Josh Saylor
Power Metrics • Mirasol IMOD Display vs. TFT LCD Displays LCD Erik Bettis
Increased Readabilty Erik Bettis
What is Bistability? • Main feature of Mirasol devices that allows for low power consumption. • Allows for pixels to be left on or off with near-zero power drain. • Uses imbalance between electro-mechanical forces and mechanical forces to hold membrane in place with very low power. • Provides built in memory for pixel placement Erik Bettis
Hysteresis • Stage 1 • Constant bias voltage holds membrane in open state • Stage 2 • Positive pulse applied to drive membrane into collapsed state • Stage 3 • Constant bias voltage holds membrane in collapsed state • State 4 • Negative pulse applied to snap membrane back to open position Erik Bettis
Bistability and Hysteresis in Mirasol Erik Bettis
Pixel Design and Color Generation • Pixels create patterns of Red, Green and Blue to create 256k color range • Interference • Reflects different wavelengths to create different colors • Red: λ = 675 nm • Green: λ = 520 nm • Blue:λ = 450 nm • Dithering • Meshes different amounts of Red, Green and Blue to create new colors • Similar to mixing paint colors on the nano-scale Josh Saylor
Examples of Spatial Dithering Color perceived Colors as Assigned Josh Saylor
Proposal of New Design Blue: 450 nm Green: 520 nm Red: 675 nm Advantage: Analog mirror control allows for multiple colors from a single unit 50 μm Glass Thin Film Electrode Pull in distance (450 nm) Rigid SiO2 Support Mirror Analog operating region (225 nm) Spring Si substrate Side Profile (not to scale) Josh Saylor
Spring Fabrication Spring can easily be machined by standard surface micro-machining procedures SiO2 Support Spring Material Compressible Design 0 V Josh Saylor
Fpull-in = = 1.4x10-6 N Vpull-in = = 5 V Pull In Voltage and Spacing Values Used Max Voltage = 5 V Permittivity = ε0 = 8.85x10-12 F/m Area = (50 μm)2 = 2.5x10-9 m2 Initial spacing = 675 nm Mirror will collapse against thin film at 5 Volts k = Fpull-in / Δxspring = 6.1 N/m Josh Saylor
Temporal and Spatial dithering still possible Pixel Design of New Layout 100 μm 350 μm New Design 4 units per pixel Current Design 42 units per pixel One color per unit Resolution Scaling Factor of 10 The old 1.4 inch display with 176 x 144 resolution would increase to 1760 x 1440 pixels with new design Josh Saylor