ID C10C: Flat Panel Display Basics Robert Dunhouse, Display BU Engineering Manager 12 October 2010 Revision 1.1 © 2010 Renesas Electronics America Inc. All rights reserved.

Robert F. Dunhouse, Jr. Displays Applications Engineering Manager Application Engineering support for North America Electrical & mechanical consultation. Customer equipment debugging. Direct communication with NEC LCD Technologies in Japan to resolve technical issues and advise direction for future designs. Design demonstration computers and display housings for field demo program. Includes circuit design & circuit board layout of LCD video interfaces and mechanical design of equipment housings. 14 years engineering experience with NEC LCD Displays. Over 25 years experience in the electronics industry Research & development at Cincinnati Microwave (founders of ESCORT radar detectors) Opened a branch office in Sydney Australia Founded US design and manufacturing company – Creative Circuits © 2010 Renesas Electronics America Inc. All rights reserved.

Display Module Solutions Robust feature sets Long-term product support Amorphous silicon (A-Si) displays Low-temperature polysilicon (LTPS) displays Industrial Mobile Displays Low power consumption Long life LEDs Thin profile and light weight design Replaceable LED light source unit LED Backlight LCDs Suited for a variety of ambient-light environments Proprietary transflective LCD technologies Super Reflective NLT (SR-NLT) Super Transmissive NLT (ST-NLT) Natural Light TFT (NLT) Sophisticated solutions Sustainable support 2D/3D displays Color enhancement E-paper On-cell touch Emerging Technologies Here are the Display Module Solutions. I am not going to cover any specific information on these solutions, but rather I want to show you where this session is focused High luminance and wide color gamut Superior image quality Ultra-wide viewing angles Super-Fine TFT (SFT) More data on a single screen 16:9 aspect ratio Wide Format LCDs 3 © 2010 Renesas Electronics America Inc. All rights reserved.

Display Module Solutions Emerging Technologies Robust feature sets Long-term product support Amorphous silicon (A-Si) displays Low-temperature polysilicon (LTPS) displays Industrial Mobile Displays New 2/3 dimensional displays Color enhancement e-Paper On-cell Touch Long Term Support/Production Low power consumption Long life LEDs Thin profile and light weight design Replaceable LED light source unit LED Backlight LCDs Suited for a variety of ambient-light environments Proprietary transflective LCD technologies Super Reflective NLT (SR-NLT) Super Transmissive NLT (ST-NLT) Natural Light TFT (NLT) Sophisticated solutions Sustainable support 2D/3D displays Color enhancement E-paper On-cell touch Emerging Technologies These are the Devices and Solutions where this presentation applies High luminance and wide color gamut Superior image quality Ultra-wide viewing angles Super-Fine TFT (SFT) More data on a single screen 16:9 aspect ratio Wide Format LCDs 4 © 2010 Renesas Electronics America Inc. All rights reserved.

Innovation © 2010 Renesas Electronics America Inc. All rights reserved.

Innovation © 2010 Renesas Electronics America Inc. All rights reserved.

Our High Performance Liquid Crystal Displays Renesas has an extensive lineup of “Industrial” grade Liquid Crystal Displays. Our products are designed with extended shock, vibration & temperature standards, enhanced front of screen performance and long product cycles. We demonstrate industry leading technologies in transflective, high resolution, high color, 3D, e-Paper and low power portable displays all to help solve many of today’s design challenges. © 2010 Renesas Electronics America Inc. All rights reserved.

Agenda Overview of an LCD display module Liquid Crystal Displays work as light valves Terms, Definitions & Measurements LCD Selection Checklist © 2010 Renesas Electronics America Inc. All rights reserved.

Key Take aways You will be able to speak intelligently about LCD displays You will be able to make informed decisions when selecting a new panel for your project. You will have enough background to attend the follow up session “Beyond the Basics” to learn about more advanced design considerations. © 2010 Renesas Electronics America Inc. All rights reserved.

Remember these? © 2010 Renesas Electronics America Inc. All rights reserved.

And now this! © 2010 Renesas Electronics America Inc. All rights reserved.

Selecting the Best Display How things have changed! Selecting the right Liquid Crystal Display determines the “face” of your product and ultimately its success. It is likely the most expensive and influential component so getting it right the first time is a must. This presentation is an entry level exposure to Liquid Crystal Displays (LCDs). It is intended to provide enough information to understand how they work, the common terms used in the industry and demonstrate a method in which to select from the many displays available in today’s market. © 2010 Renesas Electronics America Inc. All rights reserved.

Building a TFT LCD Display © 2010 Renesas Electronics America Inc. All rights reserved.

Backlight Light guide Back reflective sheet CCFL or LED Diffusion sheet Backlight assembly frame Light guide – Clear acrylic with polished ends for maximum light coupling. Used to channel light from the CCFL or LED light rails through the TFT glass assembly 1. Slab – Used for double edge lit panels. Disadvantage is heavy and thick. 2. Wedge – Used for single edge lit panels. Advantage is lighter & smaller. Disadvantage may not be as bright. Reflection Sheet 1. Film based. Used to reflect and direct light through TFT glass assembly CCFL or LED Light Rails – light sources driven normally by external circuit boards 1. Majority of all new products will be LED 2. Conversion from CCFL to LED is driven by the Reduction of Hazardous Substances started in Europe. 3. We use field Diffusion Sheet 1. Used to “diffuse” the light being channeled through the TFT display. It creates and even light plane. Backlight Assembly Frame 2. Provides the mechanical structure needed to complete the backlight assembly © 2010 Renesas Electronics America Inc. All rights reserved.

TFT Glass Assembly TFT glass assembly TFT column driver TAB Timing controller board TFT row driver TAB Row board TFT Glass Assembly 1. Complex glass assembly TFT Column Driver TABs 1. Flexible polyimide circuit populated with bonded column (source) driver IC (TAB). Heat bonded to the TFT glass table on one end and the Timing Controller (TCON) board on the other. 2. Responsible for controlling each sub-pixel. 3. This TAB circuit along with the TCON board is wrapped around the back side of the light guide. Timing Controller Board 1. Main control board. Contains an ASIC video signal timing controller, DC-DC voltage conversion & gray scale generator. TFT Row Driver TABs 1. Flexible polyimide circuit populated with bonded row (gate) driver IC (TAB). 2. Responsible for controlling the line writes. Row Driver Board 1. Row driver TABs mount and pass control information. © 2010 Renesas Electronics America Inc. All rights reserved.

Marriage of Assemblies TFT glass assembly and backlight assemblies are “married” together. Front bezel frame is added to finalize the product. Three different mounting methods Corner Edge Capture © 2010 Renesas Electronics America Inc. All rights reserved.

A Closer Look at the TFT Glass Assembly Color filter Outer polarizer ITO common electrode Alignment layer Outer Glass Substrate Epoxy sealer Short Ball spacer Bonding pad LC material Alignment layer Outer glass substrate. Glass thickness varies between 0.7, 0.5 and 0.3mm. Common is 0.5mm for 5.0” and above. Color filter – RGB vertical stripe Inner alignment layer – Polyimide film layer “wiped” with a roller in production to create alignment “grooves”. Outer polarizer Inner glass substrate Thin Film Transistor (TFT) layer Protection layer – used to protect the TFT layer during production Inner alignment layer Epoxy sealer – UV cured sealer a-Si TFT layer & pixel electrode (ITO) Inner glass substrate Inner polarizer © 2010 Renesas Electronics America Inc. All rights reserved.

How LCD Displays Work as Light Valves © 2010 Renesas Electronics America Inc. All rights reserved.

The Liquid Crystal “Cell” © 2010 Renesas Electronics America Inc. All rights reserved.

Light Passing Through © 2010 Renesas Electronics America Inc. All rights reserved.

Primary Color TFT Cells © 2010 Renesas Electronics America Inc. All rights reserved.

Common Terms and Definitions © 2010 Renesas Electronics America Inc. All rights reserved.

Size Size = Diagonal measurement of the active video area. © 2010 Renesas Electronics America Inc. All rights reserved.

Resolution Resolution = Horizontal pixels x Vertical lines Pixels Ie. – 640 x 480 is 640 pixels by 480 lines or one video “frame”. Total Thin Film Transistor (sub-pixel) count would be: 640 x 3 x 480 = 921,600 © 2010 Renesas Electronics America Inc. All rights reserved.

Contrast Ratio Contrast ratio = White luminance/Black luminance Black is not absolute. When measuring, white must be driven. © 2010 Renesas Electronics America Inc. All rights reserved.

Color Filter LCD display color filters are arranged in Red, Green & Blue vertical stripes. © 2010 Renesas Electronics America Inc. All rights reserved.

Pixels & Lines One pixel is made of three sub-pixels. Red, green & blue are the primary colors. Pixel pitch is the distance between any two like color sub-pixels Rows of pixels make up one line. © 2010 Renesas Electronics America Inc. All rights reserved.

Viewing Angle θU θR θL θD Viewing angle is measured from center perpendicular to where contrast ratio decreases to ≥10:1. “Specmanship” happens when comparing viewing angles of >5:1 contrast ratio. 12 O’clock viewing is θU and 6 O’clock is θD from the panel’s perspective. © 2010 Renesas Electronics America Inc. All rights reserved.

TN Viewing Angle Characteristics Standard TN (Twisted Nematic) panels have optimized vertical viewing angles Wash out – loss of contrast Color inversion – colors darken and invert. Appears like a “film negative” effect. © 2010 Renesas Electronics America Inc. All rights reserved.

Gray Scale Gray scale is the transition from white to black. Color is superimposed over gray scale to determine all the various shades of that color. LCD displays are typically either 18-bit or 24-bit color. This is defined as the number of color bits for each primary color times three. 24-bit color = 8 bits of Red + 8 of Green + 8 of Blue Total different colors displayed: 2 = 16.7 million © 2010 Renesas Electronics America Inc. All rights reserved.

Color Gamut CIE 1931 Chromaticity Diagram The CIE 1931 diagram represents the total colors the human eye can perceive. The color gamut of an LCD display is stated as a percentage of the National Television Standards Committee (NTSC) standard. In this example the LCD reproduces 40% of the NTSC standard. NTSC Standard Red – 0.67, 0.33 Green – 0.21, 0.71 Blue – 0.14, 0.08 White – 0.3101, 0.3162 © 2010 Renesas Electronics America Inc. All rights reserved.

Panel Response White Luminance Black Ton Toff 100% 90% 10% 0% Panel response is the time in which it takes the Liquid Crystal molecular chain to re-align and change states from white to black (Ton) and black to white (Toff). This is defined as the total response time. Response is measured with a a photo detector. Ton is measured from 90% of full luminance to 10% of full luminance. Luminance © 2010 Renesas Electronics America Inc. All rights reserved.

The lower the number the better Panel Response Notes The lower the number the better Be sure the measurement represents black-to-white-to-black times. Specmanship happens when only showing one way time. Traditional measurement method is white-to-black. In reality rarely is an image switched this way so newer comparisons will specify gray-to-gray switching times. Surprisingly gray-to-gray times can be larger than white-to-black. Response Time Compensation – momentarily applies an overvoltage to the TFT cell to quicken crystal alignment. © 2010 Renesas Electronics America Inc. All rights reserved.

Peak Luminance 50cm Photometer 1 degree focal angle Peak luminance is measured with an optical photometer placed 50cm from the center perpendicular front surface of the display. Measurements are taken in dark room conditions. Same test setup is used to measure contrast ratio. Peak luminance is measured in dark room conditions. An optical photometer is placed 50cm from center perpendicular front surface of display with an optical focal angle of 1 degree. © 2010 Renesas Electronics America Inc. All rights reserved.

Luminance Uniformity 1 2 3 4 5 Luminance uniformity defines how well an LCD maintains even luminance over the total surface of the display. Maximum and minimum luminance measurements are made in 5 locations. Luminance uniformity = Max Luminance (1 to 5) / Min Luminance (1 to 5) © 2010 Renesas Electronics America Inc. All rights reserved.

LCD Selection Checklist © 2010 Renesas Electronics America Inc. All rights reserved.

LCD Selection Checklist Panel size Select a general size based on your preliminary design. Remember to include margin for frame components. Resolution What “clarity” of image is needed? The higher the resolution the clearer the image appears. Does the manufacturer have an upgrade path? How much information needs to be displayed and once its translated to the video image will it be useable? Do you need normal aspect or wide format? 4:3 is typical, 16:9 is the newer wide format. Color or monochrome? © 2010 Renesas Electronics America Inc. All rights reserved.

LCD Selection Checklist What format is your video source? Analog RGB Parallel digital CMOS LVDS – single, dual or four channel Composite or S-Video DVI – Digital Visual Interface HDMI – High Definition Multimedia Interface Does the video format match the display? Yes – video source and panel are compatible No – A video interface will needed to convert the video source format to one compatible with the panel. © 2010 Renesas Electronics America Inc. All rights reserved.

LCD Selection Checklist What type of backlight? LED or CCFL? Most new products have transitioned to LED LEDs may still have a slight initial cost disadvantage Reduction of Hazardous Substances (RoHS) has driven the change to LED LEDs are now more energy efficient, have longer lifetimes and are more mechanically robust. © 2010 Renesas Electronics America Inc. All rights reserved.

LCD Selection Checklist Does the LCD module include a backlight driver? CCFLs use high voltage AC inverters. Safety concerns for medical applications Switching noise considerations LEDs uses constant current drivers. Typical LED string forward voltage is below 40VDC EMI low Both are approximately the same in cost. LED driver board footprints can be small. © 2010 Renesas Electronics America Inc. All rights reserved.

LCD Selection Checklist Power Newer generation LED backlit panels are generally lower power. For maximum power savings consider a reflective technology LCD. These panels enable the user to turn off the backlight in higher ambient lighting. The new e-Paper displays only consume power when writing a new image. Once the image is written ALL power can be removed. Certain premium viewing angle technologies consume more logic power. © 2010 Renesas Electronics America Inc. All rights reserved.

LCD Selection Checklist What environment will the panel be used in? Indoor or outdoor Temperature Moisture Direct sunlight exposure Solar thermal loading Preservation of contrast Vandal proof Shock & vibration requirements? Industrial rated panels have higher shock, vibration & temperature parameters. Industrial panels tend to be mechanically larger than commercial panels. Frames are more robust and backlights brighter. © 2010 Renesas Electronics America Inc. All rights reserved.

LCD Selection Checklist Bottom line is the best test is your eyes. Schedule a side-by-side comparison of several panels that look good on paper. The Renesas Display Business Unit has an easy to use demo system. © 2010 Renesas Electronics America Inc. All rights reserved.

Action Obtain several LCD datasheets for comparison purposes. Attend the follow up session ID C22C: Flat Panel Displays “Beyond the Basics” to learn more advanced design and integration considerations. The session is in room Royal E&F at 5:15-6:15PM. © 2010 Renesas Electronics America Inc. All rights reserved.

Innovation © 2010 Renesas Electronics America Inc. All rights reserved.

Questions? © 2010 Renesas Electronics America Inc. All rights reserved.

Thank You © 2010 Renesas Electronics America Inc. All rights reserved.