Photometric and Colorimetric Measurement Procedures for Airborne Electronic Flat Panel Displays
|Publication Date:||1 May 2014|
This SAE Aerospace Recommended Practice (ARP) contains methods used to measure the optical performance of airborne electronic flat panel display (FPD) systems. The methods described are specific to the direct view, liquid crystal matrix (x-y addressable) display technology used on aircraft flight decks. The focus of this document is on active matrix, liquid crystal displays (LCD). The majority of the procedures can be applied to other display technologies, however, it is cautioned that some techniques need to be tailored to different display technologies.
The document covers monochrome and color LCD operation in the transmissive mode within the visual spectrum (the wavelength range of 380 to 780 nm). These procedures are adaptable to reflective and transflective displays paying special attention to the source illumination geometry.
Photometric and colorimetric measurement procedures for airborne direct view CRT (cathode ray tube) displays are found in ARP1782. Optical measurement procedures for airborne head up displays (HUDs) can be found in ARP5287.
Generally, the procedures describe manual single point measurements. The individual procedures may be readily incorporated into automated testing equipment (ATE) or other automated environments. This also includes, but is not limited to Fourier scopes and video imaging devices.
This report is published by SAE to advance the state of technical and engineering sciences. The use of this Technical Report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.
This document is intended as a guide toward standard measurement practices in support of ARP4256 and AS8034 but is not limited to its requirements. The use of this document is not as a basis for legal regulation.
The purpose of ARP4260 is to provide display measurement procedures and is referenced in:
• ARP4256, Design Objectives for Liquid Crystal Displays for Part 25 (Transport) Aircraft,
• AS8034, Minimum Performance Standard for Airborne Multipurpose Electronic Displays,
• FAA AC 25-11 A, Electronic Flight Deck Displays,
• FAA TSO-C113, Airborne Multipurpose Electronic Displays,
• FAA ANM-03-111-18, Policy Statement on the Installation of Transport Category Airplane Flightdeck Liquid Crystal Displays.
AC 25-11 and TSO-C113 call out AS8034. AS8034 and ARP4256 refer to ARP4260. ANM-03-111-18 calls out ARP4256.
Appendix B provides a cross reference between the ARP4256 and AS8034 requirements and ARP4260 test procedures.
Sections 2 and 3 cover background for general procedures and equipment setups. Section 4 provides the specific test procedures for the parameters.
This SAE Recommended Practice is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances. To this end, the ARP4260 Revision A team actively participated with other industry display measurement groups including the following.
• VESA Flat Panel Display Measurements Standard,
• SID ICDM (Society for Information Display International Committee on Display Measurement) Display Measurement Standard,
• NIST (National Institute for Standards and Technology) Flat Panel Laboratory, http://www.fpdl.nist
• British National Physical Laboratory (NPL) - Displays, http://www.npl.co.uk
• SAE vehicular automotive displays standard metrology.
As part of the Revision A work, the same representative avionics sample display was tested in seven optical laboratories. The results of the round robin validation testing helped determine that the optical requirement verification procedures defined in ARP4260 are valid, accurate, repeatable, and achievable in a means that is conducive to cost effective procurement and certification. Measurement result data reduction examples have been added to Revision A to help the user.
Field of Application
This document defines four classes of tests. Each class of test is applicable to the different phases of a product's life [e.g., engineering development (Class 1), mockup simulator tests (Class 2), production/quality assurance (Class 3), and service/flight readiness (Class 4)]. The test requirements for each of these phases differ and hence the test procedures for each test class may differ. Each procedure in this document is Class 1 unless otherwise stated.
Classes of Tests
Class 1 - Laboratory Tests - The objective of tests in this class is to verify the design of the display system. Tests in this class are most appropriate in an engineering laboratory environment or as part of a certification program.
Class 2 - Mockup, Simulator Tests - The installation performance testing involves placing the display in a cockpit mock up; and placing the cockpit mock-up in an ambient illumination environment that could simulate typical illuminance and luminance conditions. The display would then be evaluated by pilots (or other suitable personnel) to verify that the visual performance complies with 4.3.3 of AS8034 Revision A and 4.2.1 in ARP4256 Revision A. These tests also evaluate the displays interaction with other displays, lighting, and controls.
Class 3 - Production/Quality Assurance - The objective of this test class is to verify that every display has been manufactured or repaired to meet specified requirements. Tests in this class are most appropriate for acceptance and/or end item tests.
Class 4 - Maintenance/Flight Readiness - The objective of tests in this class is to verify that display performance is within acceptable flight limits. Tests in this class are most appropriate for field service and flight line inspection.
Categories of Test
The test procedures of this document are divided into three categories:
Photometric: Luminance and Chromaticity
Geometric: Spatial Measurements
Temporal: Time-Based Measurements
The test procedures of this document are designed to be performed under the following constraint: no internal access to the unit under test is allowed for Class 3 and Class 4 testing.