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`Mercedes-Benz USA, LLC, Petitioner - Ex. 1010
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`Optoelectronic//
`Fiber-Optic/ Application/
`manual
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`Page 2 of 42
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`Library of Congress Cataloging in Publication Data
`Hewlett-Packard Company. Optoelectronics Division.
`Applications Engineering Staff
`Optoelectronics/fiber-optics applications manual.
`
`Published in 1977 under title: Optoelectronics
`applications manual.
`Includes index.
`1. Light emitting diodes.
`3. Fiber optics.
`devices.
`TK7871.89.L53H48 1981
`ISBN 0-07-028606-X
`
`2. Optoelectronic
`Gage, Stan.
`II. Title.
`621.36'7
`80-19814
`
`Copyright © 1981, 1977 by Hewlett-Packard Company. All rights reserved. Printed in the United States of
`America. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form
`or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written
`permission of Hewlett-Packard.
`
`567890
`
`HDHD
`
`8987654321
`
`Hewlett-Packard assumes no responsibility for the use of any circuits described
`herein and makes no representations or warranties, express or implied, that such
`circuits are free from patent infringement.
`
`Page 4 of 42
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`

`1.0 LED THEORY
`
`TABLE OF CONTENTS
`
`1.1 The Theory of P-N Junction Electroluminescence.
`Semiconductor Energy Gap
`1.1.1
`Semiconductor Doping
`1.1.2
`1.1.3
`The P-N Junction
`1.1.4
`Recombination
`1.1.5 Materials Available for LED Devices
`1.1.6
`Direct and Indirect Band-Gap Materials
`1.1. 7
`Enhanced Photon Emission in Indirect Gap Materials
`Quantum Efficiency of LED Devices
`Relative Efficiency
`.
`Material Processing
`.
`LED Structure
`1.4.1
`1.4.2
`Transparent vs. Opaque Substrate
`The Effect of Temperature Variation on LED Parameters
`1.5.1
`Forward Voltage as a Function of Temperature
`Change in Peak Wavelength as a Function of Temperature .
`1.5.2
`1.5.3
`Change in Output Power vs. Temperature
`
`1.2
`1.3
`1.4
`
`1.5
`
`2.0 LED LAMPS
`
`2.1
`
`Physical Properties of an LED Lamp Device
`Plastic Encapsu Ia ted LED Lamp
`2.1.1
`2.1. 2
`Fresnel Loss
`.
`2.1.3
`Critical Angle Loss
`2.1.4 Optical Efficiency
`External Quantum Efficiency
`2.1.5
`Internal Quantum Efficiency
`2.1.6
`Calculating Radiated Flux
`2.1.7
`Luminous Efficacy and Power Per Unit Solid Angle
`2.1.7.1
`2.1.7.2
`Calculating Total Power
`Magnification and Luminous Intensity
`2.1.8
`Diffused and Undiffused LED Lamps .
`2.1.9
`2.2 LED Lamp Packaging
`.
`.
`2.2.1
`Lead Frame Packaging .
`The Industry Standard T-1 3/4 and T-1 LED Lamps.
`2.2.2
`The Subminiature LED Lamp
`2.2.3
`2.2.4
`The Rectangular LED Lamp .
`The Hermetic LED Lamp .
`2.2.5
`2.2.6
`LED Lamps that Include Other Components
`2.3 LED Lamp Characterization Information
`2.3.1
`Light Output and Color Matching .
`2.3.2
`Maximum Temperature Derated Operating Limits.
`2.3.3
`Pulsed Operating Conditions .
`2.3.4
`Time Average Luminous Intensity
`2.4 Visual Applications of LED Lamps
`2.4.1
`Introduction
`.
`2.4.2
`Relative Efficiency
`
`.
`
`.
`
`1.1
`
`1.1
`1.1
`1.1
`1.2
`1.2
`1.2
`1.3
`1.3
`1.3
`1.4
`1.6
`1.6
`1.6
`1.8
`1.8
`1.8
`1.8
`
`2.1
`
`2.1
`2.1
`2.1
`2.2
`2.3
`2.3
`2.3
`2.3
`2.3
`2.3
`2.5
`2.6
`2.6
`2.6
`2.7
`2.8
`2.8
`2.9
`2.9
`2.9
`2.10
`2.11
`2.13
`2.14
`2.14
`2.14
`2.16
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`Page 5 of 42
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`TABLE OF CONTENTS (Continued)
`
`2.4.3
`
`2.4.4
`
`2.4.5
`
`Driving a11 LED Lamp .
`.
`.
`.
`2.4.3.1
`LED Electrical Characteristics
`Resistive Current Limiting
`2.4.3.2
`Constant Current Limiting
`2.4.3.3
`LED-Logic Interface
`2.4.3.4
`2.4.3.5
`Worst Case Design
`LED Arrays
`.
`.
`.
`.
`.
`.
`2.4.4.1
`Introduction
`.
`.
`2.4.4.2
`Designing an X-V Addressable LED Array
`Design of a Microprocessor Controlled LED Array
`2.4.4.3
`2.4.4.4
`Analog Bar Graph Arrays .
`.
`.
`.
`.
`Backlighting
`.
`.
`.
`.
`.
`.
`..
`.
`.
`2.4.5.1
`Fundamental Backlighting Requirements
`2.4.5.2
`ON Sterance Design Considerations
`2.4.5.3
`Backlighting Construction for Small-to-Medium Legend Areas
`2.4.5.4
`Backlighting Constructio.n for Very Large Legend Areas
`2.5 Communications and Signalling Applications
`.
`.
`.
`.
`.
`.
`.
`.
`2.5.1
`Device Characterization for Communications and Signalling
`2.5.2
`Flux Properties in Signalling .
`2.5.3
`Lens System with LEOs
`.
`.
`2.5.4
`No-Lens Signalling
`.
`.
`.
`.
`2.5.5
`Signalling Over Long Distance
`2.5.6
`Film Exposure
`
`3.0 OPTO-ISOLATORS .
`
`.
`
`3.1 Optoisolator Theory
`3.1.1
`Photo Emitter .
`3.1.2
`Optical Medium
`3.1.3
`Photodetector
`3.1.4
`Amplifier Options
`3.2 Parameter Characterization
`3.2.1
`Isolation
`3.2.2
`.
`.
`.
`Insulation
`3.2.3
`Speed of Response
`3.2.4
`Reverse Coupling.
`3.2.5
`CTR (or Gain)
`Isolator Packaging
`3.3.1
`Packaging of Plastic 01 P Isolators
`3.3.2
`Packaging of High Reliability Isolators
`3.3.3
`Compatibility of Six and Eight Pin Isolators .
`3.3.4
`Layout Considerations for Optically Coupled Isolators
`3.3.5
`Bypass Capacitor Requirements .
`3.4 CTR Degradation .
`
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`3.3
`
`3.4.1
`3.4.2
`3.4.3
`3.4.4
`3.4.5
`
`Introduction - Optocouplers Aging Problem
`Causes
`.
`.
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`Degradation Model .
`. ·.
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`.
`.
`Higher Order Effects
`Procedure for Calculation of CTR Degradation .
`
`2.18
`2.18
`2.19
`2.19
`2.20
`2.21
`2.24
`2.24
`2.25
`2.28
`2.30
`2.35
`2.36
`2.39
`2.42
`2.42
`2.42
`2.44
`2.44
`2.45
`2.46
`2.51
`2.55
`
`3.1
`
`3.1
`3.1
`3.1
`3.2
`3.4
`3.5
`3.5
`3.9
`3.10
`3.14
`3.14
`3.15
`3.15
`3.15
`3.15
`3.17
`3.17
`3.20
`3.20
`3.20
`3.22
`3.24
`3.26
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`Page 6 of 42
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`

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`TABLE OF CONTENTS (Continued)
`
`3.4.6
`
`Practical Application
`3.4.6.1
`Example 1
`3.4.6.2
`Example 2
`3.4.6.3
`Example 3
`3.4.6.4 Consideration of the Optically Coupled Gate .
`3.4.6.5
`Example 4
`.
`.
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`.
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`3.5 Analog Applications of Optically Coupled Isolators
`3.5.1
`Introduction
`.
`.
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`3.5.2 Analog Model for an Optically Coupled Isolator
`.
`.
`Types of Analog Circuits
`3.5.3
`.
`3.5.4
`Servo Isolation Amplifier
`.
`.
`.
`3.5.5
`Differential Isolation Amplifier
`AC Coupled Isolation Amplifier .
`3.5.6
`3.5.7
`Digital Isolation Techniques
`.
`.
`Isolated Analog to Digital Techniques.
`3.5.7.1
`Isolated Analog to Digital to Analog Techniques .
`3.5.7.2
`3.6 Digital Applications .
`.
`.
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`3.6.1
`Line Receivers.
`.
`.
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`.
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`Resistive Terminations
`3.6.1.1
`Active Terminations.
`3.6.1.2
`Common Mode Rejection (CMR) Enhancement.
`3.6.2
`3.6.3 Data Rate Enhancement
`3.6.4
`Party Line Operation (Bussing, Current Looping)
`3.6.5
`Telephone Circuit Applications
`3.6.6 Microprocessor Applications
`
`4.0
`
`PHOTODIODES .
`
`.
`
`.
`
`.
`
`4.1
`
`4.2
`
`Theory and Characterization
`4.1.1
`Photodiode Design and Construction
`4.1.2
`Photodiode Characterizaton
`.
`.
`.
`.
`Photodiode Operation
`.
`.
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`4.2.1
`Circuit Model .
`.
`.
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`4.2.2
`Basic Amplifier Arrangements
`Suggested Applications .
`4.2.3
`
`5.0
`
`DISPLAYS.
`
`Types of LED Dispalys .
`5.0.1
`Display Fonts .
`5.0.2
`The Display Subsystem .
`5.0.3
`Data Handling in Display Systems
`5.0.4
`5.1 Numeric Displays with an On-Board Integrated Circuit (OBI C) .
`The HP 5082-7300 OBIC Display Family . .
`5.1.1
`5.1.1.1
`Character Font
`.
`.
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`.
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`The On-board Integrated Circuit.
`5.1.1.2
`5.1.1.3
`Temperature Considerations
`.
`.
`Intensity Control for Hexidecimal Displays Using Pulse Width Modulation .
`Interfacing a Microprocessor to an OBIC Numeric Display
`.
`.
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`.
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`5.1.2
`5.1.3
`
`i
`
`3.27
`3.29
`3.31
`3.31
`3.32
`3.33
`3.34
`3.34
`3.35
`3.35
`3.35
`3.37
`3.38
`3.39
`3.39
`3.40
`3.42
`3.43
`3.43
`3.48
`
`3.49
`3.56
`3.64
`3.69
`3.71
`
`4.1
`
`4.1
`4.1
`4.3
`4.6
`4.6
`4.8
`4.8
`
`5.2
`
`5.2
`5.2
`5.2
`5.4
`5.4
`5.6
`5.6
`5.6
`5.8
`5.9
`5.9
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`Page 7 of 42
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`

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`TABLE OF CONTENTS (Continued)
`
`5.2.2
`
`5.2.3
`5.2.4
`
`5.2.5
`
`5.2.6
`5.2.7
`
`5.2.8
`
`5.2 Strobable-Seven-Stretched Segment Displays.
`5.2.1
`Description.
`.
`.
`.
`.
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`5.2.1.1
`Construction
`Data Sheet Parameters
`5.2.1.2
`Determining Display Drive Conditions .
`Maximum DC Current (I DC), Junction Temperature (T J), and Package Resistance (OJA)
`5.2.2.1
`5.2.2.2
`Forward Voltage (VF) and LED Dynamic Series Resistance (Rs)
`5.2.2.3
`Variation of Forward Voltage with Change in Temperature .
`5.2.2.4
`Operational Curves for Strobing an LED Device.
`.
`.
`5.2.2.5
`Maximum DC Current (IDC MAX) and Temperature Derating
`Sample Calculation of a Typical and Worst Case Design, Strobed Operation
`Relative Efficiency and Light Output .
`.
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`Sample Calculation of Time Average Luminous Intensity
`5.2.4.1
`5.2.4.2
`Digit-to-Digit and Segment-to-Segment Luminous Intensity Ratio.
`Driving a Seven Segment Display
`.
`.
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`.
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`5.2.5.1
`Direct DC Driving a Display
`.
`.
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`.
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`High Speed Counter Using DC Drive
`5.2.5.2
`Concept of Strobed (Multiplexed) Operation
`5.2.5.3
`Interfacing Microprocessors to Seven Segment Displays
`.
`Detection and Indication of Segment Failures in Seven Segment LED Displays
`5.2.7.1
`Seven-Segment Self-Test Circuit for Common Anode Displays .
`.
`5.2.7.2
`Self Test Circuit for Seven-Segment Displays and Associated Decoder Driver
`Suggested Drive Currents for Stretched Seven Segment Displays Used in Various Ambient
`Light Levels
`5.3 Monolithic Displays .
`.
`5.3.1
`Introduction
`.
`5.3.2
`Effect of External Lens
`5.3.3
`Construction of Monolithic Displays
`5.3.4
`Electrical-Optical Characteristics.
`.
`5.3.5
`Driving Monolithic Displays
`.
`.
`.
`5.3.6
`Interfacing Microprocessors to Monolithic Seven Segment Displays
`5.4 Alphanumeric Displays .
`.
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`The 5x7 LED Array .
`.
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`5.4.1
`5.4.2
`Character Generation in 5x7 Arrays
`5.4.3
`Implementation of a 16 Character Row Scan Display .
`5.4.4 Alphanumeric Displays with On-Board Data Storage
`5.4.4.1
`Drive Circuit Concept
`.
`.
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`Interface Circuits for HP HDSP-2000
`5.4.4.2
`
`5.14
`5.14
`5.14
`5.15
`5.15
`5.15
`5.16
`5.17
`5.17
`5.17
`5.17
`5.17
`5.20
`5.20
`5.21
`5.21
`5.22
`5.22
`5.26
`5.30
`5.30
`5.31
`
`5.32
`5.33
`5.33
`5.35
`5.36
`5.37
`5.40
`5.40
`5.43
`5.43
`5.43
`5.47
`5.47
`5.50
`5.51
`6.1
`
`6.1
`. 6.2
`6.2
`6.4
`6.4
`6.5
`6.7
`6.7
`6.7
`
`.
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`6.0 CONTRAST ENHANCEMENT FOR LED DISPLAYS
`
`6.1 Contrast and Contrast Ratio
`.
`6.2 Eye Response, Peak Wavelength and Dominant Wavelength
`6.3 Filter Transmittance.
`.
`.
`.
`6.3.1
`Plastic Filters .
`6.3.2
`Optical Glass Filters .
`6.4 Wavelength Filtering.
`.
`.
`.
`Filtering Standard Red Displays ('Ap == 655 nm) .
`6.4.1
`6.4.2
`Filtering High-Efficiency Red Displays (1\p == 635 nm)
`.
`.
`.
`.
`Filtering Yellow Displays (1\p == 583 nm)
`6.4.3
`
`.
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`Page 8 of 42
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`TABLE OF CONTENTS (Continued)
`
`.
`.
`.
`.
`Filtering Green Displays (f,p = 565 nm)
`6.4.4
`6.5 Reduction of Reflected Ambient Light as Provided by a Contrast Filter .
`6.5.1
`Effectiveness of a Wavelength Filter in an Ambient of Artificial Lighting
`Effectiveness of a Wavelength Filter in Daylight Ambients
`6.5.2
`6.6 Special Wavelength Filters and Filters in Combination
`6.6.1
`The Purple Contrast Filter for Red LED Displays
`6.6.2
`Filters in Combination
`6.7 Louvered Filters .
`.
`.
`6.8 Circular Polarizing Filters .
`6.9 Anti-Reflection Filters, Mounting Bezels and Other Suggestions
`
`6.7
`6.9
`6.10
`6.12
`6.13
`6.13
`6.13
`6.14
`6.15
`6.16
`
`7.0 PHOTOMETRY AND RADIOMETRY
`
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`. 7.1
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`Spectral Relationships
`7.1
`.
`.
`7.2 Geometrical Relationships.
`7.3 Photometric and Radiometric Measurements
`7.3.1
`Spectral Effects
`.
`.
`.
`7.3.2
`Intensity Measurement .
`7.3.3
`Sterance Measurement
`7.3.4
`Flux Measurement
`.
`
`.
`
`8.0 RELIABILITY OF OPTOELECTRONIC DEVICES
`
`8.1 Reliability Aspects of the LED Semiconductor Chip
`8.2 Reliability Aspects of LED Packaging .
`.
`.
`.
`.
`
`9.0 MECHANICAL HANDLING CONSIDERATIONS FOR LED DEVICES
`
`7.1
`7.2
`7.6
`7.6
`7.7
`7.9
`7.9
`
`8.1
`
`8.1
`8.1
`
`9.1
`
`9.1
`9.1
`9.1
`9.2
`9.2
`9.2
`9.3
`9.3
`9.3
`9.5
`9.5
`9.5
`9.6
`9.6
`9.6
`9.6
`9.6
`9.7
`9.7
`9.8
`9.9
`9:10
`9.11
`9.12
`9.12
`
`.
`
`Similarity in LED Packages
`9.1
`9.2 The Bending of Leads
`.
`.
`9.3 The Silver Plated Lead Frame.
`9.3.1
`The Silver Plating.
`.
`9.3.2
`The Effect of Tarnish
`9.3.3
`Storage and Handling
`Solders, Fluxes, and. Surface Conditioners
`9.4.1
`Solders
`.
`.
`9.4.2
`Fluxes
`.
`.
`9.4.3
`Surface Conditioners
`Soldering Process.
`.
`9.5.1 Wave Soldering
`9.5.2
`Hand Soldering
`9.5.3
`Cutting the Leads
`9.5.4
`Printed Circuit Board
`Post Solder Cleaning.
`Types of Cleaners
`9.6.1
`9.6.2
`Bulk Cleaning Processes
`9.6.3
`Special Cleaning Instructions for Monolithic PC Board Displays
`Socket Mounting
`.
`.
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`.
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`.
`Special Socket Assemblies for LED Displays.
`9.7.1
`.
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`Heat Sinking
`.
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`OBI C Display Assembly with On-Board Heat Sink .
`9.8.1
`9.8.2
`A Display Assembly with Heat Pipe
`9.8.3
`List of Manufacturers
`.
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`9.4
`
`9.5
`
`9.6
`
`9.7
`
`9.8
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`10.0
`
`FIBER OPTICS AND OPTOCOUPLERS FOR DIGITAL DATA TRANSMISSION ................... 10.1
`
`TABLE OF CONTENTS (Continued)
`
`10.1
`10.2
`
`10.3
`
`10.4
`
`10.5
`
`Fundamental System Arrangements ............................................ 10.1
`Fiber Optic vs. Wire/Optocoupler Considerations ................................... 1 0.2
`10.2.1
`Ground Loop Effects .............................................. 10.2
`10.2.2
`Cross Talk and EMI Effects .......................................... 10.2
`Bandwidth Comparison ............................................. 10.3
`10.2.3
`Terminal Requirements ............................................. 10.3
`10.2.4
`Mechanical/Optical Considerations ...................................... 10.3
`10.2.5
`Optocoupler/Wire-Cable Data Link Realizations .................................... 10.3
`Simplex Data Transmission ........................................... 10.3
`10.3.1
`Duplex Data Transmission ........................................... 10.5
`10.3.2
`10.3.3 Multiplex Data Transmission .......................................... 10.6
`Fiber Optic System Realization ............................................... 10.8
`1 0.4.1
`Properties of Fiber Optic Systems ...................................... 1 0.8
`10.4.2
`Description of the Hewlett-Packard Fiber Optic System ........................ 10.11
`10.4.3
`Simplex Transmission .............................................. 10.12
`10.4.4
`Duplex Transmission ............................................... 10.12
`10.4.5 Multiplex Transmission ............................................. 10.13
`Data Formatting ......................................................... 1 0.13
`1 0.5.1
`Channel Capacity ................................................. 10.13
`10.5.2
`Clocking ....................................................... 10.14
`10.5.3
`Self-Clocking Codes ............................................... 10.14
`Multiplexing .................................................... 10.17
`10.5.4
`Interfacing With Established Standards ................................... 10.20
`10.5.5
`
`11.0
`
`SUNLIGHT VIEWABLE LED DISPLAYS .............................................. 11.1
`
`11.1
`
`11.2
`
`11.3
`11.4
`
`Contrast Enhancement Techniques Needed to Achieve Readability in Bright Sunlight ........... 11.1
`The LED Color .................................................. 11.1
`11.1.1
`Luminance Contrast and the Luminance Index .............................. 11.2
`11.1.2
`Chrominance Contrast and the Chrominance Index ........................... 11.4
`11.1.3
`11.1.4
`The Discrimination Index ............................................ 11.4
`11.1.5
`Front Surface Reflections ........................................... 11.5
`A List of Neutral Density Gray Filters For Use With Sunlight Viewable LED Displays .... 11.7
`11.1.6
`The Display System Concept to Achieve Viewability in Sunlight ......................... 11.7
`11.2.1
`The Display Devices ............................................... 11. 7
`11.2.2
`A Practical Example ............................................... 11. 7
`A Special Filter for Yellow Alphanumeric LED Displays .............................. 11.9
`The Importance of Low Thermal Resistance Design ................................. 11.1 0
`11.4.1
`The Effect of LED Junction Temperature On Light Output ..................... 11.10
`11.4.2
`Thermal Resistance and the Allowed Operating Ambient Temperature .............. 11.1 0
`11.4.3
`LED Junction Temperature vs. Pulsed Operation ............................ 11.11
`
`12.0
`
`BACKLIGHTING .............................................................. 12.1
`
`12.1
`
`Annunciator Brightness .................................................... 12.1
`12.1.1
`The Concept of Luminous Sterance ..................................... 12.1
`12.1.2
`Luminous Sterance From A Lambertian Light Emitting Surface .................. 12.2
`12.1.3
`Luminous Sterance From A Non-Lambertian Light Emitting Surface ............... 12.2
`12.1.4
`Definition of Minimum Luminous Sterance ................................ 12.2
`12.1.5
`The Effect of Color On Observed Brightness ............................... 12.3
`12.1.6
`Luminous Sterance Levels For Comfortable Viewing .......................... 12.4
`
`Page 10 of 42
`
`

`

`TABLE OF CONTENTS (Continued)
`
`12.2
`
`12.3
`12.4
`
`12.5
`12.6
`
`Legends .............................................................. 12.5
`Legend Font .................................................... '12.5
`12.2.1
`12.2.2
`Fabricating A Legend .............................................. 12.6
`12.2.2.1 The Transparent Substrate .................................... 12.6
`12.2.2.2 The Silkscreen Paint ........................................ 12.6
`12.2.2.3 Legend Artwork For Alignment ................................ 12.6
`Attaching the Legend to the Face of the LED Light Source ..................... 12.7
`12.2.3
`Cross Talk Across the Face of a Multi-Function Annunciator .................... 12.7
`12.2.4
`Front Panel Design for use with LED Backlighted Legends ............................. 12.8
`The LED as a Light Source .................................................. 12.1 0
`12.4.1
`LED Flux Output and the Size of an Illuminated Area for a Given Luminous Sterance ... 12.10
`The LED Light Source vs. The Incandescent Bulb ............................ 12.11
`12.4.2
`LED LightBar Modules .................................................... 12.12
`The Use of LED Light Bar Modules in Edge Lighted Panels ............................. 12.13
`
`13.0
`
`OPTOCOUPLERS IN INDUSTRIAL CONTROL SYSTEMS .................................. 13.1
`
`13.1
`
`13.2
`
`13.3
`
`13.4
`
`Application Methods for Optocouplers in Industrial Control Systems ...................... 13.1
`13.1.1
`AC Voltage Sensing- Wet and Dry ..................................... 13.1
`13.1.2
`AC Voltage Rectification ............................................ 13.2
`Detection Techniques .............................................. 13.2
`13.1.3
`DC Voltage Sensing ................................................ 13.3
`13.1.4
`Current Sensing .................................................. 13.3
`13.1.5
`Threshold Detection ............................................... 13.3
`13.1.6
`Protection Considerations for Optocouplers in Industrial Control Systems ................... 13.5
`Line Transients .................................................. 13.5
`13.2.1
`Transient Suppression Techniques ...................................... 13.5
`13.2.2
`Capacitive Coupling ............................................... 13.6
`13.2.3
`Bounce Filtering .................................................. 13.7
`13.2.4
`CTR Degradation ................................................. 13.7
`13.2.5
`Insulation ...................................................... 13.7
`13.2.6
`Power Dissipation ................................................. 13.7
`13.2.7
`13.2.8
`Overvoltage Protection ............................................. 13.8
`Design Examples ........................................................ 13.8
`13.3.1
`De.sign Example 1 ................................................. 13.8
`Design Example 2 ................................................. 13.12
`13.3.2
`An Optocoupler with a Built-In Switchi.ng Threshold .......................... , ...... 13.14
`Device Characteristics .............................................. 13.15
`13.4.1
`Design Examples Using the HCPL-3700 .................................. 13.15
`13.4.2
`13.4.2.1 Example 1. DC Voltage Sensing ................. ' .............. 13.16
`13.4.2.2 Example 2. AC Operation ................................... 13.18
`13.4.2.3 AC Operation With No Filtering ................................ 13.18
`Input Filtering for AC Operation ................... · ............. 13.19
`13.4.2.4
`13.4.2.5 Example 3. AC Operation with Improved Threshold Control and Accuracy ... 13.20
`13.4.2.6 Output Filtering ........................................... 13.21
`13.4.2.7 Threshold Accuracy Improvement ............................... 13.23
`13.4.2.8 Example 4. Dedicated Lines for Remote Control .................... 13.24
`General Protection Considerations for the HCPL-3700 ......................... 13.25
`13.4.3
`Thermal Considerations ............................................. 13.26
`13.4.4
`13.4.5 Mechanical and Safety Considerations ................................... 13.26
`13.4.5.1 Mechanical Mounting Considerations ............................. 13.26
`13.4.5.2 Electrical Safety Gonsiderations ................................ 13.26
`Electrical Connectors .............................................. 13.27
`Appendix I. List of Parameters ...............•....................... 13.27
`
`13.4.6
`13.4.7
`
`Page 11 of 42
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`

`

`14.0
`
`INTERFACING DISPLAYS TO MICROPROCESSOR SYSTEMS .............................. 14.1
`
`TABLE OF CONTENTS (Continued)
`
`14.1
`
`14.2
`
`14.3
`14.4
`14.5
`14.6
`14.7
`
`Microprocessor Operation .................................................. 14.1
`14.1.1
`CPU Operation ................................................... 14.2
`Bus Structure .................................................... 14.3
`14.1.2
`14.1.3
`Programming Considerations .......................................... 14.7
`Interrupts ...................................................... 14.7
`14.1.4
`Display Interface Techniques ................................................ 14.8
`14.2.1
`Comparison of Interface Techniques .................................... 14.10
`DC Driven Controllers ..................................................... 14.11
`Refresh Controllers ....................................................... 14.11
`Decoded Data Controllers .................................................. 14.21
`Coded Data Controllers .................................................... 14.27
`Display Processor Controllers ................................................ 14.29
`
`15.0
`
`OPTICAL SENSING ............................................................ 15.1
`
`15. "I
`
`15.3
`
`15.4
`
`15.5
`
`Introduction ........................................................... 15.1
`System Elements ................................................. 15.1
`15.2.1
`Optical Transfer Function ........................................... 15.1
`15.2.2
`Coupling Fundamentals ............................................. 15.1
`15.2.3
`Lens Fundamental,s ................................................ 15.3
`15.2.4
`Lens Coupling ................................................... 15.4
`15.2.5
`Reflector Fundamentals ............................................. 15.5
`15.2.6
`15.2.7
`Confocal Coupling ................................................ 15.5
`Lens Reflective Coupling ............................................ 15.6
`15.2.8
`HEDS-1000 Reflective Coupling ....................................... 15.7
`15.2.9
`Optical Sensor Parameters .................................................. 15.8
`Introduction .................................................... 15.8
`15.3.1
`15.3.2 Modulation Transfer Function ........................................ 15.8
`15.3.3
`Depth of Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.10
`15.3.4
`HEDS-1000 Total Transfer Function .................................... 15.11
`HEDS-1000 Logic Interfacing ................................................ 15.12
`Photodiode Interconnection .......................................... 15.12
`15.4.1
`15.4.2
`Stray Photocurrent- Ips ............................................ 15.13
`lpR/Ips Ratio ................................................... 15.13
`15.4.3
`15.4.4
`Depth of Field with Respect to Maximum Signal Point ........................ 15.13
`Amplifier Considerations ............................................ 15.14
`15.4.5
`15.4.6
`Transresistance- TTL Interface ....................................... 15.14
`CMOS Interface .................................................. 15.15
`15.4.7
`Current Feedback Amplifier .......................................... 15.16
`15.4.8
`15.4.9
`Current-Voltage Feedback Amplifier .................................... 15.17
`15.4.10
`LSTTL Interface ................................................. 15.18
`Reflective Sensor Applications ............................................... 15.19
`Rotary Tachometry ............................................... 15.19
`15.5.1
`15.5.2
`HEDS-1000 Analog Tachometer ....................................... 15.19
`. ......... 15.20
`Digital Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
`15.5.3
`15.5.4
`Paper Edge Sensor ................................................ 15.20
`15.5.5
`Bar Code Scanner ................................................. 15.22
`
`INDEX ........................................................................... 1-1
`
`Page 12 of 42
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`

`

`kiw.
`
`,
`
`Page 13 of 42
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`Page 13 of 42
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`

`

`9.0
`
`MECHANICAL HANDLING CONSIDERATIONS
`FOR LED DEVICES
`
`The first stage in designing a circuit utilizing <m
`optoelectronic device is selecting the proper device for the
`application. The second step is to establish the electrical
`operating conditions and design the circuit. The third step
`is to install the optoelectronic device into the physical
`assembly, be
`it a printed circuit board, front panel
`mounting or some other mounting arrangement. The
`mounting considerations are primarily mechanical
`in
`nature, requiring attention to such items as the similarity of
`LED packages, the bending of leads, silver plated lead
`frames, soldering and post solder cleaning, socket mounting
`and heat sinking if required. Reliable operation of the LED
`device
`is more positively assured when all of these
`mechanical considerations have been given careful
`attention.
`
`T0-18 header. The devices will withstand considerable
`mechanical and temperature stress without any effect upon
`performance.
`
`BONDING WIRE
`
`WEDGE BOND TO
`ANODE LEAD
`
`LEAD FRAME
`
`BALL WIRE BOND
`TO TOP CONTACT
`
`LED, DIE ATTACHED
`TO CATHODE LEAD
`
`L - - - ~DEVICE PACKAGE
`
`FORMED BY
`ENCAPSULANT
`
`Figure 9.1-1 Basic Construction of a Plastic Encapsulated LED
`Device.
`
`9.1
`
`Similarity in LED Packages
`
`PRINTED CIRCUIT
`METALLIZATION
`
`Most plastic encapsulated LED devices are assembled using
`the
`lead frame
`technology. The exceptions are some
`stretched segment display devices which are assembled on
`substrates. Independent of the lead frame or package
`design, a lead frame device has the LED die attached
`directly to one lead and wire bonded across to another lead
`as shown in Figure 9.1-1.
`'
`
`The primary thermal path to the LED is the cathode lead.
`Any mechanical and thermal stress applied to the leads is
`transmitted directly to the LED, die attach and wire bonds.
`The plastic encapsulant forms the device package and is the
`only supporting element for the lead frame. Therefore, the
`integrity of the encapsulation must be maintained to insure
`throughout its
`reliable operation of the LED device
`expected operating life.
`
`Devices that do not use an encapsulating epoxy are most
`likely assembled on a ceramic substrate. Thick film
`metallization is usually applied to the face of the substrate.
`The LED is die attached to one metallization pad and wire
`bonded across to another pad, as shown in Figure 9.1-2.
`The circuit metallization is the primary thermal path from
`the LED to the leads, and the substrate acts as a secondary
`thermal path to the external ambient. The substrate isolates
`the LEDs and wire bonds from mechanically applied
`stresses; the amount of isolation dependent upon the type
`of substrate and package configuration. Devices of this
`construction are mechanically more rugged than a plastic
`encapsulated device and are more tolerant of temperature
`extremes.
`
`One other type of device is assembled on a TO header, such
`as the high-reliability LED lamp which is packaged on a
`
`9.1
`
`LEAD PIN
`
`SUBSTRATE
`
`Figure 9.1-2 Basic Construction of an Unencapsulated, Substrate
`LED Device.
`
`9.2
`
`The Bending of Leads
`
`In many LED lamp applications, it is necessary to bend the
`leads in order to mount the lamp at some angle other than
`90° to the surface of a PC board. The leads of a lamp may
`be easily bent without introducing mechanical stresses
`inside
`the plastic package. The proper procedure for
`bending leads is illustrated in Figure 9.2-1. Bend the leads
`prior to soldering. Firmly grip the leads at the base of the
`lamp package with a pair of needle nose pliers. The pliers
`form a mechanical ground to absorb the stresses when
`bending. Bend the leads, one at a time, to the angle desired.
`
`9.3
`
`The Silver Plated Lead Frame
`
`Since the price of gold has increased several times during
`the past few years, the cost of a gold plated lead frame has
`increased substantially, necessitating the search for an
`alternative. The impact of this cost increase has been
`industry wide. Many plating material alternatives were
`examined, and silver plating offered most of the desired
`propertie,s of gold, while remaining price competitive when
`compared to other materials.
`
`Page 14 of 42
`
`

`

`FIRMLY GRASP LEADS
`BEND DOWN
`AT BASE OF LAMP
`\
`WITH NEEDLE NOSE
`PLIERS, SUPPORT ~
`LEADS WITH PLIERS
`~
`WHILE BENDING.
`. ~
`
`Figure 9.2-1 Correct Method to Bend the Leads of an LED Lamp.
`
`By using silver plating, no additional manufacturing process
`steps are required. Silver has excellent electrical
`conductivity. LED die attach and wire bonding to a silver
`lead frame is accomplished with the same reliability as with
`a gold lead frame. Also, soldering to a silver lead frame
`provides a reliable electrical and mechanical solder joint_
`Soldering silver plated lead frame LED devices into a
`printed circuit board is no more complicated than soldering
`LED devices with gold plated lead frames.
`
`9.3.1 The Silver Plating
`
`The silver plating process is performed as follows: the lead
`frame base metal is cleaned and then plated with a copper
`strike, nominally 50 microinches (0.00127 mm) thick.
`Then a 150 microinch (0.00381 mm) thick plating of silver
`is added. A "brightener" is usually added to the silver
`plating bath to insure an optimum surface texture to the
`silver plating. The term "brightener" comes from the
`medium bright surface reflectance of the silver plate. Figure
`9.3.1-1 illustrates the metallographic cross-section of the
`silver plating system as it would appear with a 1200X
`magnification.
`
`150 ,uinch
`MINIMUM
`SILVER
`PLATING
`
`Since silver is porous with respect to oxygen, the copper
`strike acts as an oxygen barrier for the lead frame base
`metal. Thus, oxide compounds of the base metal are
`prevented from forming underneath the silver plating.
`Copper is miscible and readily diffuses into silver to form a
`solution that has a low eutectic point. This inter-diffusion
`between the copper strike and the silver overplate improves
`the solderability of the overall plating system. If basic
`soldering time and temperature limits are not exceeded, a
`lead frame base metal-copper-silver-solder metallurgical
`system will be obtained.
`
`9.3.2 The Effect of Tarnish
`
`Silver resists attack by most dry and moist atmospheres,
`such as carbon monoxide or high temperature steam.
`Halogen gases do attack silver, however, once the initial
`ftlm layer is formed the process does not continue.
`
`Silver reacts chemically with sulfur to form tarnish, silver
`sulfide (Ag2S). The build-up of tarnish is the primary
`reason for poor solderability. However, the density of the
`tarnish and the kind of solder flux used actually determine
`the solderability. As the density o