Frederick M. Meyer

Reflective Display Characterization: Temporal and Spatial Viewability Measurements of Holographic Polymer Dispersed Liquid Crystal (HPDLC) Display Samples

Holographically formed polymer dispersed liquid crystal (HPDLC) materials meet the requirements for a video rate reflective display. In order to produce a saturated color from a Bragg reflector, the number of index changing layers becomes critical. The fabrication process affects the number of layers forming the reflector, and, as a result, the bandwidth and optical characteristics, including reflection intensity, direction, and spread, of the reflector. The cell thickness and the liquid crystal mixture affect the voltage at which the cell operates and the speed at which the liquid crystal material can switch from the reflective to non-reflective state. The cell designer is forced to work with all of these design parameters simultaneously. This research continues previous work evaluating reflective HPDLC display samples including a method to measure temporal response and refine color reflection characterization.

AMLCD cockpit: promise and payoffs

The active matrix liquid crystal display (AMLCD) has become the preferred flight instrument technology in avionics multifunction display applications. Current bubble canopy fighter cockpit applications involve sizes up to 7.8 X 7.8 in. active display. Dual use avionics versions of AMLCD technology are now as large as 6.7 X 6.7 in. active display area in the ARINC D sized color multifunction display (MFD). This is the standard instrument in all new Boeing transport aircraft and is being retrofitted into the C-17A. A special design of the ARINC D instrument is used in the Space Shuttle cockpit upgrade. Larger sizes of AMLCD were desired when decisions were made in the early 1990s for the F-22. Commercial AMLCD technology has now produced monitors at 1280 X 1024 resolution (1.3 megapixels) in sizes of 16 to 21 in. diagonal. Each of these larger AMLCDs has more information carrying capacity than the entire F-22A cockpit instrument panel shipset, comprising six separate smaller AMLCDs (1.2 megapixels total). The larger AMLCDs are being integrated into airborne mission crewstations for use in dim ambient lighting conditions. It is now time to identify and address the technology challenges of upgrading these larger AMLCDs for sunlight readable application and of developing concepts for their integration into advanced bubble canopy fighter cockpits. The overall goals are to significantly increase the informational carrying capacity to bring both sensor and information fusion into the cockpit and, thereby, to enable a significant increase in warfighter situational awareness and effectiveness. A research cockpit was built using specialized versions of the IBM 16.1 in and two smaller 10 in. AMLCDs to examine human factors and display design issues associated with these next-generation AMLCD cockpit displays. This cockpit was later upgraded to allow greater reconfigurability and flexibility in the display hardware used to conduct part- task mission simulations. The objective optical characterization of the AMLCDs used in this simulator and the cockpit design are described. Display formats under consideration for test in this cockpit are described together with some of the basic human factors engineering issues involved. Studies conducted in this cockpit will be part of an ongoing joint effort of the hardware-focused aerospace displays team and the pilot-focused human factors team in the Air Force Research Laboratorys Crew System Interface Division. The objective of these studies is to ascertain the payoffs of the large AMLCD promise in combat cockpits.

AFRL battlespace visualization branch display characterization facility

Digital displays will play a critical role in providing a common battlespace picture whether in the aircraft cockpit, command and control facility or carried by ground troops. Advanced display technologies will be key to providing our warfighters with needed information. The purpose of the Display Characterization Facility at Wright-Patterson AFB is to provide quantitative performance data on current and upcoming display technologies and evaluate these technologies for specific Air Force applications. This requires an understanding not only of the specific display technology and its capabilities and limitations but also the capabilities and limitations of the human visual system, the tasks to be performed and characteristics of the environment which may affect the operator-display interaction. To this end, the Display Characterization Laboratory conducts both display hardware measurements and assessments of human performance using the displays under expected environmental conditions. Common display measurements are described along with their implications for operator visual performance.

Military display performance parameters

The military display market is analyzed in terms of four of its segments: avionics, vetronics, dismounted soldier, and command and control. Requirements are summarized for a number of technology-driving parameters, to include luminance, night vision imaging system compatibility, gray levels, resolution, dimming range, viewing angle, video capability, altitude, temperature, shock and vibration, etc., for direct-view and virtual-view displays in cockpits and crew stations. Technical specifications are discussed for selected programs.

Readability evaluation of an active matrix electrophoric ink display

A low-power, yet sunlight readable, display is needed for dismounted applications where the user must carry the power source. Such a display could potentially replace paper checklists and maps with electronic counterparts. A reflective active matrix electrophoretic ink display (AMEPID) was evaluated as a candidate technology for such applications. This display technology uses ambient illumination, rather than competing with it, and requires power only when rewriting the display. The device was tested for viewability under a variety of lighting conditions. Readability of displayed text, as compared to standard print on white paper, was evaluated in an indoor office environment and in outdoor lighting conditions. Viewability of the display with night vision goggles (NVGs) was evaluated under simulated full moon, starlight, and overcast illumination conditions. Objective measurements of luminance, contrast ratio and reflectance were conducted under corresponding irradiance conditions and viewing angles using state-of-the-art photometric and radiometric measurement equipment. In addition to visible spectrum measurements, infrared (IR) reflectance and contrast were measured for the extended spectrum of 720-1700 nm. Results are discussed in terms of performance criteria for military displays, which are often much more demanding than for civil applications.

Holographic polymer-dispersed liquid crystal sample characterization

Holographically formed polymer dispersed light crystal (HPDLC) materials have the potential to enable creation of a full motion video rate reflective display technology with excellent color, contrast, reflectance and good power efficiency. Current HPDLC display research focuses on the improvement of angular viewability and reduction of the drive voltage. Measurements of HPDLC devices have begun at AFRL to verify and expand measurements made by dpiX LLC. Specular and diffuse reflections are examined in terms of angular and spectral reflectance distributions. Presently reported measurements verify the ability of an HPDLC device to shift the reflected signal image away from the front- surface substrate specular angle (source image glare) by some 10 degree(s) and to expand the spread of the reflected signal image (full-width-half maximum) from a bout 1-2 degree(s) to 4- 10 degree(s) for a point illumination source under worst orientation conditions. Colors were stable over 20 degree(s) of viewing angle. Potential defense applications include replacing paper in cockpits and crewstations.

Status of display systems in B-52H

Display technologies for the B-52 were selected some 40 years ago have become unsupportable. Electromechanical and old cathode ray tube technologies, including an exotic six-gun 13 in. tube, have become unsupportable due to the vanishing vendor syndrome. Thus, it is necessary to insert new technologies which will be available for the next 40 years to maintain the capability heretofore provided by those now out of favor with the commercial sector. With this paper we begin a look at the status of displays in the B-52H, which will remain in inventory until 2046 according to current plans. From a component electronics technology perspective, such as displays, the B-52H provides several 10-year life cycle cost (LCC) planning cycles to consider multiple upgrades. Three Productivity, Reliability, Availability, and Maintainability (PRAM) projects are reviewed to replace 1950s CRTs in several sizes: 3, 9, and 13 in. A different display technology has been selected in each case. Additional display upgrades in may be anticipated and are discussed.

Stainless steel display evaluation

Active matrix organic light emitting diode (AMOLED) technology is one candidate to become a low power alternative in some applications to the currently dominant, active matrix liquid crystal display (AMLCD), technology. Furthermore, fabrication of the AMOLED on stainless steel (SS) foil rather than the traditional glass substrate, while presenting a set of severe technical challenges, opens up the potential for displays that are both lighter and less breakable. Also, transition to an SS foil substrate may enable rollable displays - large when used but small for stowage within gear already worn or carried or installed. Research has been initiated on AMOLED/SS technology and the first 320 x 240 color pixel 4-in. demonstration device has been evaluated in the AFRL Display Test and Evaluation Laboratory. Results of this evaluation are reported along with a research roadmap.

Wrist display concept demonstration based on 2-in. color AMOLED

The wrist watch needs an upgrade. Recent advances in optoelectronics, microelectronics, and communication theory have established a technology base that now make the multimedia Dick Tracy watch attainable during the next decade. As a first step towards stuffing the functionality of an entire personnel computer (PC) and television receiver under a watch face, we have set a goal of providing wrist video capability to warfighters. Commercial sector work on the wrist form factor already includes all the functionality of a personal digital assistant (PDA) and full PC operating system. Our strategy is to leverage these commercial developments. In this paper we describe our use of a 2.2 in. diagonal color active matrix light emitting diode (AMOLED) device as a wrist-mounted display (WMD) to present either full motion video or computer generated graphical image formats.

Performance specification for control tower display systems

Personnel in airport control towers monitor and direct the takeoff of outgoing aircraft, landing of incoming aircraft and all movements of aircraft on the ground. Although the primary source of information for the Local Controller, Assistant Local Controller and the Ground Controller is the real world viewed through the windows of the control tower, electronic displays are also used to provide situation awareness. Due to the criticality of the work to be performed by the controllers and the rather unique environment of the air traffic control tower, display hardware standards, which have been developed for general use, are not directly applicable. The Federal Aviation Administration (FAA) requested assistance of Air Force Research Laboratory Human Effectiveness Directorate in producing a document which can be adopted as a Tower Display Standard usable by display engineers, human factors practitioners and system integrators. Particular emphasis was placed on human factors issues applicable to the control tower environment and controller task demands.