Robert B. Wood

Performance assessment of an LCOS-based head-up display

The development of a liquid crystal on silicon (LCOS) projector based Head-Up Display (HUD) is nearing completion and the first products are being readied for Flight Test. Rockwell Collins Flight Dynamics (RCFD) has reported previously on the designs, performance requirements, and measured performance of two prototype versions, as well as the potential benefits of the technology and the technical challenges remaining. This paper reviews some of the key performance requirements, enabling technologies, and preliminary measured results from the first pre-production units. There is also a comparison of the LCOS projector based HUD to two evolving digital HUD technologies.

High-resolution LCD projector for extra-wide-field-of-view head-up display

LCD projection-based cockpit displays are beginning to make entry into military and commercial aircraft. Customers for commercial Head-Up Displays (HUDs)(including airframe manufacturers) are now interested in the adaptation of the technology into existing and future HUD optical systems. LCD projection can improve mean-time-between-failure rates because the LCDs are very robust and the light sources can be replaced with scheduled maintenance by the customer without the need for re-calibration. LCD projectors promise to lower the cost of the HUD because the cost of these displays continues to drop while the cost of CRTs remain stable. LCD projectors provide the potential for multi-colors, higher brightness raster, and all-digital communication between the flight computer and display unit. Another potential benefit of LCD projection is the ability to increase field of view and viewing eyebox without exceeding existing power budgets or reducing display lifetime and reliability compared to the capabilities provided by CRTs today. This paper describes the performance requirements and improved performance of a third-generation LCD projection image source for use in a wide field of view head-up display (HUD) optical system. This paper will focus on new HUD requirements and the application of various technologies such as LCOS microdisplays, arc lamps, and rear-projection screens. Measured performance results are compared to the design requirements.

A Holographic Head-Up Display For Automotive Applications

A high performance multiple color automotive head-up display system using a holographic element embedded within a standard automotive windshield is described. The system uses an optical system designed to compensate the aspheric curvature characteristics of the windshield and to project the display ahead of the vehicle. The image source is a high contrast transmissive liquid crystal display illuminated with a high intensity white light source. The display is clearly visible against all ambient light conditions tested. The system has been designed for volume production.

Holographic head-up display combiners with optimal photometric efficiency and uniformity

Head-Up Displays (HUDs) utilizing holographic combiner elements can suffer from poor display brightness uniformity across the head motion volume or field of view. The brightness non-uniformity is due to angle differences between the construction and the enduse orreconstruction geometries. This problem is especially acute when holographic combinerelements are positioned relatively close to the pilots design eye location, when large head motion volumes are desired, and when narrow-band phosphors (e.g. P-53) are used. This paper presents a hologram design approach that maximizes the HUD combiner phosphor reflectivity, the transmissivity through the combiners, and the display brightness uniformity. This technique can be applied to HUDs using dual combiners or wide field-of-view combiners.