1、AEROSPACE RECOMMENDED PRACTICEARP4256REV.AIssued 1996-12Revised 2001-12Superseding ARP4256Design Objectives for Liquid Crystal Displaysfor Part 25 (Transport) AircraftFOREWORDThis SAE Aerospace Recommended Practice (ARP) is intended as a guide toward standard practice and is subject to change to kee
2、p pace with experience and technical advances. This document provides additional information pertinent to AS8034. TABLE OF CONTENTS1. SCOPE .41.1 Purpose42. REFERENCES .42.1 Applicable Documents .42.1.1 SAE Publications .42.1.2 FAA Publications52.2 Related Publications 52.2.1 SAE Publications .52.2.
3、2 FAA Publications52.2.3 U.S. Military Publications .52.2.4 CIE Publications.52.2.5 RTCA/EUROCAE Publications 62.3 Definitions 63. GENERAL REQUIREMENTS.63.1 Equipment Functions .63.2 Environmental Conditions 63.3 Smoke and Toxicity 63.4 Malfunction Indication 73.5 Glass Breakage .7SAE Technical Stan
4、dards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole re
5、sponsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2008 SAE International All rights reserved. No part of this publication may be reproduced, st
6、ored 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 SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 E
7、mail: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org Reaffirmed 2008-01SAE ARP4256 Revision A- 2 -TABLE OF CONTENTS (Continued)4. DETAIL REQUIREMENTS74.1 Display Visual Characteristics74.1.1 Viewing Characteristics74.1.2 Symbol Alignment 74.1.3 Matrix Anomalies84.1.4 Crosstalk 84.1.5 Jitt
8、er .84.1.6 Line Width Uniformity.84.1.7 Symbol Quality.84.1.8 Flicker 84.1.9 Symbol Motion .84.1.10 Response Time 94.1.11 Image Retention.104.1.12 Defects.104.1.13 Multiple Images114.2 Photo-Colorimetric Characteristics.114.2.1 General 114.2.2 Luminance .114.2.3 Contrast Ratio (CR)164.2.4 Color 174.
9、2.5 Gray Scale .194.2.6 Specular Reflections 204.2.7 Inactivated Segments.204.3 Operating Time 204.3.1 Warm-Up204.3.2 Lag Time 204.3.3 Data Update.215. GLOSSARY OF TERMS.215.1 Chromaticity .215.2 Color 215.3 Color Banding (Matrix) .225.4 Color Fringing (Matrix) .225.5 Contrast Ratio (CR)225.6 Crosst
10、alk 225.7 Design Eye Position (DEP) 235.8 Display Element .235.9 Failed-On .235.10 Failed-Off .235.11 Flicker 235.12 Gray Scale .235.13 Image Retention.235.14 Instrument 23SAE ARP4256 Revision A- 3 -TABLE OF CONTENTS (Continued)5.15 Jitter .245.16 Line Width 245.17 Luminance .245.18 Milliradian (mra
11、d) .245.19 Moire 245.20 Pixel .245.21 Racheting.245.22 Roping245.23 Segmented Display245.24 Service Limits.255.25 Specular Reflections 255.26 Stair Stepping.255.27 Stroboscopic Flicker.255.28 Viewing Envelope.25SAE ARP4256 Revision A- 4 -1. SCOPE:This document covers monochrome and color LCDs (trans
12、missive, transflective, and reflective), both matrixed and segmented in format, and is applicable to the following types of displays: a. Flight and navigation displaysb. Engine, systems, and warning devicesc. Control displays In this document the terms “LCD”, “LCD Display”, “Display”, and “Instrumen
13、t” are synonymous and encompass the display system (e.g., LCD device, drivers, backlight, display processor, etc.), not just the device. 1.1 Purpose:This document recommends design and performance criteria for liquid crystal displays (LCDs) on the flight deck of aircraft subject to Part 25 certifica
14、tion. It is intended as guidance for the certifying authority. A secondary purpose is to share information about the unique characteristics of LCDs and how they relate to the flight deck. 2. REFERENCES:2.1 Applicable Documents:The following publications form a part of this specification to the exten
15、t specified herein. In the event of conflict between the text of this specification and references cited herein, the text of this specification takes precedence. Nothing in this specification, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1.1 SA
16、E Publications: Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. ARP450D Flight Deck Visual, Audible and Tactile SignalARP571C Flight Deck Controls and Displays for Communication and Navigation Equipment for Transport AircraftARP1068B Flight Deck Instrumentation, Display Criter
17、ia and Associated Controls for Transport AircraftAIR1093 Numeral, Letter and Symbol Dimensions for Aircraft Instrument DisplaysARP4102 Core Document, Flight Deck Panels, Controls and DisplaysARP4102/7 Electronic DisplaysARP4103 Flight Deck Lighting and Visual InterfaceARP4105 Nomenclature and Abbrev
18、iations for Use on the Flight DeckAS8034 Minimum Performance Standard for Airborne Multipurpose Electronic DisplaysAMS 2521B Reflection Reducing Coatings for Instrument Glasses SAE ARP4256 Revision A- 5 -2.1.2 FAA Publications: Available from the Federal Aviation Administration, 800 Independence Ave
19、nue, SW, Washington, DC 20591. FAR Part 25/JAR 25TSO-C113 Airborne Multipurpose Electronic Displays 2.2 Related Publications:The following publications are provided for information purposes only and are not a required part of this SAE Aerospace Recommended Practice. 2.2.1 SAE Publications: Available
20、 from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. ARP1161 Crew Station Lighting - Commercial AircraftARP1782 Photometric and Colorimetric Measurement Procedures for Direct View CRT DisplaysARP1874 Design Objectives for CRT Displays for Part 25 (Transport) AircraftARP4032 Human Engineerin
21、g Considerations in the Application of Color to Electronic Aircraft DisplaysARP4101 Core Document, Flight Deck Layout and FacilitiesARP4260 Photometric and Colorimetric Measurement Procedures for Airborne Direct View Flat Panel DisplaysARP4067 Design Objectives for CRT Displays for Part 23 Aircraft
22、2.2.2 FAA Publications: Available from the Federal Aviation Administration, 800 Independence Avenue, SW, Washington, DC 20591. Advisory Circular 25-11, Transport Category Airplane Electronic Display SystemsAdvisory Circular 23.1311-1A, Installation of Electronic Displays in Part 23 Airplanes2.2.3 U.
23、S. Military Publications: Available from DODSSP, Subscription Services Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094. AFGS-87213B (USAF) Displays, Airborne, Electronically/Optically Generated 2.2.4 CIE Publications: Available outside of the U.S. from Bureau Centrale De La CIE, 5
24、2, Boulevard Malesherbes, 75008 Paris, France and inside the U.S. from United States National Committee of the Commission Internationale De LEclairage, c/o Thomas Lemons, TLA-Lighting Consultants, Inc., 7 Pond Street, Salem, MA 01970-4893. Supplement No. 2 to CIE Publication No. 15 Recommendations o
25、n Uniform Color Spaces Color Difference Equations - Psychometric Color Terms SAE ARP4256 Revision A- 6 -2.2.5 RTCA/EUROCAE Publications: Available from RTCA, Inc., 1140 Connecticut Avenue, Suite 1020, Washington, DC 20036. RTCA DO-160D/EUROCAE ED-14D Environmental Conditions and Test Procedures for
26、Airborne EquipmentRTCA DO-178B/EUROCAE ED-12B Software Considerations in Airborne Systems and Equipment Certification 2.3 Definitions:Definitions used in this document shall be as noted in the Glossary of Terms defined in Section 5. The word “shall” is used to express an essential (mandatory) requir
27、ement. Conformance requires that there be no deviation. The word “should” is used to express a recommended requirement. Deviation from the specified recommendation may require justification. 3. GENERAL REQUIREMENTS:3.1 Equipment Functions:The design objectives for flight deck displays as set forth i
28、n ARP4102/7 are applicable to LCD displays unless they are superseded by or conflict with the recommendations of this document. 3.2 Environmental Conditions:Except as detailed in appropriate sections of this document, the performance requirements specified in Section 4 apply over the applicable envi
29、ronmental conditions and test procedures set forward in RTCA document DO-160C and over the useful life of the equipment. In no case shall performance be degraded so as to lead to erroneous interpretation or loss of displayed data. 3.3 Smoke and Toxicity:No material used shall liberate gases or fumes
30、 that are detrimental to performance of the aircraft or to performance or to health of personnel. SAE ARP4256 Revision A- 7 -3.4 Malfunction Indication:Means must be provided to indicate malfunctions or failures to the appropriate crew member in a positive manner (reference ARP4102, 6.2). It is not
31、practical to use built-in-self-test procedures to monitor the functionality of all the addressable elements in liquid crystal display devices. One manual means to detect addressable element malfunctions is to provide a “push-to-test” procedure which activates all display elements in “on” and “off” s
32、tates. Displayed fonts, symbols, indicia, etc. should be designed to be tolerant of addressable element defects and failures whenever practical. Particular emphasis should be given to precluding or mitigating failures which could result in hazardously misleading information. Inconspicuous and undete
33、cted loss of information could contribute to hazardously misleading information. Consideration should be given to drive and addressing techniques to avoid the loss of information resulting from the failure of rows, columns, and/or elements. 3.5 Glass Breakage:Front glass strength shall be sufficient
34、 to withstand normal impacts that can be expected in the flight deck environment without cracking, breaking, or loss of LCD edge seal. 4. DETAIL REQUIREMENTS:4.1 Display Visual Characteristics:4.1.1 Viewing Characteristics: All indicating means displayed (indicia, pointers, symbols, etc.) shall be c
35、ompletely visible from any eye position within the viewing envelope(s) as specified by the equipment manufacturer. Each installation shall be examined to verify that the design eye position(s) and allowable head motion envelope(s) (reference 2.2.1, 4.1.1.1, and 6.1.5 of ARP4102) are within each view
36、ing envelope. Cross-cockpit viewing to the other pilots displays should be provided to achieve the capability recommended by ARP4102. The cross-cockpit viewing angle is installation dependent and is usually a compound angle. NOTE: The cockpit viewing angle requirements may far exceed 45 degrees. 4.1
37、.2 Symbol Alignment: Symbols which are interpreted relative to each other (i.e., cursors on scales, command bars against reference points, etc.) shall be aligned to preclude misinterpretation of information. SAE ARP4256 Revision A- 8 -4.1.3 Matrix Anomalies: Since the display is an array of discrete
38、 elements, displayed information may have visible spatial and color anomalies. Stair stepping, line width variation, and moire are examples of spatial anomalies; color banding and color fringing are examples of color anomalies. Anomalies are especially visible in dynamic images and may not be visibl
39、e in static images. The extent of the anomaly is dependent on many factors including the size, shape, and arrangement of the display elements, construction of the symbol, rate, direction, and increment of motion and luminance control of the elements. The display shall have no matrix anomalies which
40、cause distraction or erroneous interpretation. This shall be assessed with both static and dynamic formats. 4.1.4 Crosstalk: Crosstalk should not be readily apparent or distracting. 4.1.5 Jitter: There should be no discernible display jitter when viewed within the viewing envelope. Jitter of 0.3 mra
41、d peak-to-peak from any point within the viewing envelope is a suggested upper limit, but that may not be acceptable in some instances. 4.1.6 Line Width Uniformity: When viewed from the design eye position (DEP), lines of a specified color and luminance should appear uniform in width at all rotation
42、al or translational orientations of the line. Line width variation should not be readily apparent or cause distracting visual effects. Lines with a minimum line width less than 70% of the maximum line width may produce an undesirable visual “roping” effect. 4.1.7 Symbol Quality: Symbols should not h
43、ave distracting gaps or geometric distortions. Symbol quality characteristics shall not cause erroneous interpretations; any distorted dimension should not exceed one half the local line width. 4.1.8 Flicker: Flicker should not be readily discernible or distracting under day, twilight, or night cond
44、itions, considering both foveal and full peripheral vision, and using an operational format most susceptible to producing flicker. This is intended to include stroboscopic flicker induced by vibration and/or pilot motion. 4.1.9 Symbol Motion: Display symbology that is in motion (translation and/or r
45、otation) should not have distracting jitter, jerkiness, or ratcheting effects. Dynamic symbols should maintain luminance (per 4.1.10), contrast, color, line width, and symbol quality characteristics independent of their rate of motion. Pointers and bar graphs should be designed with built in hystere
46、sis or smoothing of the displayed value such that when a constant or near constant value of a parameter is to be displayed, objectionable motion is eliminated. SAE ARP4256 Revision A- 9 -4.1.10 Response Time: Response time limitation shall not produce undesirable artifacts which could lead to the er
47、roneous interpretation or loss of displayed information. Such artifacts include smearing of moving images and loss of luminance. These effects may be temperature dependent and shall be evaluated over the operating temperature range. For either increasing or decreasing commanded luminance, the ratio
48、of integrated luminance change (luminance perceived by the eye) to commanded steady state luminance should be greater than a suggested value of 70%. Mathematically, this is described as: (Eq. 1)FIGURE 1(Eq. 2)Perceived Luminance Change (ON)Lt() tdtotug179tuLcLto()- 0.7=Perceived Luminance Change (OF
49、F) 1Lt() tdtotug179tuLcLto()- 0.7=SAE ARP4256 Revision A- 10 -FIGURE 24.1.10 (Continued):where: L(t)= Function luminance change with respect to timeLc= Commanded steady state luminance= Initial steady state luminancetu= Data update period (reference 4.3.3)to= Start of the update period (time = zero) NOTE: The data update period is here assumed to be longer than the refresh cycle. For displays with slowly changing symbol positions, tushall be equal to the data update period or the minimum time req
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