Since their introduction more than forty years ago by BAE Systems, Head up Displays have relied on the Cathode Ray Tube as their image source. The progression of electronic technology in recent years has prompted the search for an alternative to the tube as the primary image source. Until very recently, this work has centred on the Liquid Crystal Display (LCD). These are relatively inefficient devices, whether they be transmissive or reflective and this low efficiency therefore requires a very intense source of light to illuminate them. The difficulty of packaging, achieving a high reliability and a long life seemed to limit the application of the Laser as the illumination source. However with an innovative Laser illuminator working with the highly efficient DMD the author describes a 'next generation' HUD (Head Up Display) design.
Measurement of the parameters required to calibrate and Acceptance Test a Head Up Display have traditionally been made using a Photometer and Theodolite. As HUD complexity has increased it has become an increasingly lengthy process subject to error. The concept of using a calibrated CCD Camera to combine the functions in a highly automated system is not new but creating a practical system for production with traceability to the traditional method has proven difficult. This paper describes the introduction of an automated measurement system to the Eurofighter Head Up display programme.
This study arose because of a perception that a larger horizontal field of view for a Head Up Display installed in a civil transport was automatically better. There is a lack of scientific analysis to confirm or deny this view. The study addresses three situations: -Crosswind Landings, Curved Approaches and Runway Exit Angle and each situation is assess with three HUD FoV's. It was found that the Crosswind situation was limited by the aircraft landing restrictions not HUD Field of View. The curved approaches gave a more mixed conclusion but in general the time that the glidescope was within the FoV was not significantly enhanced with a 40degree FoV HUD compared to the nominal 36degree. The runway exit angle analysis showed that alternative means must be found to show the turn-off point rather than reliance on the FoV.
The Helmet Mounted Display has been in development for over 25 years and with few exceptions those systems in service have incorporated a miniature Cathode Ray Tube as the display source. The exceptions have been the use of Light Emitting Diodes in Helmet Sighting displays. The argument for Flat Panel Displays has been well rehearsed and this paper provides a summary of the available technologies but with a rationale for a decision to use Reflective Liquid Crystal devices. The Paper then describes sources of illumination and derives the luminance required from that source.
The increase in air transport traffic in recent years, coupled with the projected increases in the next decade, has led to increasing interest on the part of aircraft operators in both increasing safety in the ever more crowded skies and the efficiency of the aircraft themselves. This paper describes a Visual Guidance System (VGS) for civil transport aircraft, which provides guidance, not only during takeoff, enroute and landing, but also potentially on the ground. This final stage enables the concept of 'gate-to-gate' guidance to be implemented.
There is a view that the cockpit of the future might be configured without a Head Up Display (HUD) and that the HUD functions will be replaced by a Helmet Mounted Display (HMD). This paper compares the two display types and examines the obstacles to establishing an HMD as a Primary Flight Instrument. The conclusion is that the accuracy of either display with 'dumb' weapons is comparable at low level, but neither is adequate at high level. The integrity of an HMD is deemed inadequate at present.
The manufacture of Flat Panel Displays (FPDs) is dominated by Far Eastern sources, particularly in Active Matrix Liquid Crystal Displays (AMLCD) and Plasma. The United States has a very powerful capability in micro-displays. It is not well known that Europe has a very active research capability which has lead to many innovations in display technology. In addition there is a capability in display manufacturing of organic technologies as well as the licensed build of Japanese or Korean designs. Finally, Europe has a display systems capability in military products which is world class.
The dominance of the Cathode Ray Tube (CRT) in the specialist area of Head Up Displays (HUDs) is being challenged by Flat Panel Displays (FPDs). The luminance and contrast requirements are very demanding, a problem compounded by the low efficiency of the display devices. This paper discusses the application of transmissive or reflective Liquid Crystal Display (LCD) to the HUD and particularly reviews the illumination of the display. The conclusion is that in the near term a transmissive configuration with an RF coupled or Light Emitting Diode (LED) backlight shows most promise but that longer term micro-lasers allied with the reflective configuration should be a better solution.
The resolution, cost and physical volume of modern imaging sensors has made their use as part of an airborne Autonomous Landing Guidance System (ALGS) a practical enterprise. This paper describes a latest generation Head Up Display (HUD) that is currently undergoing certification in the United States for Air Transport applications. The modes of operation of the HUD are described. The technical capabilities of the system are illustrated by video footage of its performance on flight test in actual low visibility conditions.
The market for military avionics head down displays for which Active Matrix Liquid Crystal Displays (AMLCD) has been specified is both well established and substantial. Typical major programs such as F-22, V-22 and Joint Strike Fighter (JSF) amount to over 15,000 displays. Nevertheless there is an insecurity about the situation because of the dependency upon Japanese and Korean manufacturers and the vagaries of the commercial market. The U.S. has only 7% of the world's manufacturing capability in AMLCD and is seeking alternative technologies to regain a hold in this lucrative business. The U.S. military manufacturers of AMLCD are capable, but can never achieve the benefits of scale that Commercial Off The Shelf (COTS) equipment can offer. In addition to the commercial and political concerns, there are still performance issues related to AMLCD and there is a view that emissive displays in particular can offer advantages over AMLCD. However, it is beneficial to be able to tailor display sizes and there are doubts about the ability of current flat panel technologies to achieve custom, or indeed large area panels either economically, or reliably. It is in this arena that projection displays may be the optimum solution.
HMDs have severe demands on luminance and resolution. There is a requirement to view the display over a range of ambient illumination from full sunlight to night and to provide high accuracy for weapon release. Installation constraints further complicate the optical design and mass is crucial for the head mounted hardware. Currently the only display device that can met these demands is the monochrome cathode ray tube (CRT). This paper explores the potential for replacing the CRT. THe problem areas such as installation, illumination and drive are discussed and the suitability of various technologies is considered. The potential for color is also reviewed.
Avionics head up and helmet mounted displays have severe demands on luminance and resolution. There is a requirement to view the display over a range of ambient illumination from full sunlight to night and to provide high accuracy for weapon release. Installation constraints further complicate the optical design and mass is crucial for the head mounted hardware. Currently, the only display device that can meet these demands is the monochrome cathode ray tube (CRT). This paper explores the potential for replacing the CRT with a flat panel device (FPD). The problem areas such as installation, illumination and drive are discussed and the suitability of various flat panel technologies is considered. The potential for color is also reviewed. The paper is intended as an introduction to the application and future papers will address achievements as development progresses.
In the miliary cockpit the Head Up Display (HUD) is being challenged by the Head Mounted Display. This paper considers why the latest fighter aircraft still retain a HUD and how the requirements of the advanced instrument panel have directed the design of the HUD in particular into the use of holographic optics.
Fabrication of a wide field of view Head Up Display has required a trade off between performance and ease of manufacture. First generation holographic HUDs employed two distinct approaches: (1) Single element powered holographic combiner with a complex relay lens system. (2) Multiple element unpowered holographic combiners with a medium complexity combiner. The manufacturing difficulties of the first approach limit the achievable accuracy whereas the second approach, although easier to make, has obscuration and transmission problems. This paper describes an advanced HUD design using computer generated holographic construction techniques to fabricate a HUD which meets the extreme performance requirements of the latest aircraft but which remains a reasonable production item.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.