Description

The High-Density Display (HDD) is a one-of-a-kind tiled display system which provides high-quality high-density display capabilities for the most visually demanding applications. Our current efforts are focused on improving tile-to-tile color uniformity and increasing pixel density. Some of the unique features of this display system include:

Unique Features
Single light source	Provides a single even color temperature of white light for all tiles (even as the lamp ages).
Shared dicroic filters	Provides the same red, green, and blue color hue to each tile's optics module.
Randomized fiber distribution	Delivers even light intensity to each tile's optics module.
High-density	Special lenses enable each tile to produce a 21-inch diagonal image (same pixels per inch as a high-quality CRT). We've even tested down to 16-inch diagonal tiles.
High-resolution	Each tile can produce a native 1280x1024 pixel image. We currently have a test system which has a 3x1 tile arrangement and is planned to expand to 3x3 (3840x3072 pixels).

Most tiled displays (often called "Power Walls" or "Video Walls") are constructed using a matrix of video projectors which are used to produce a single large output image. Unfortunately, due to variations in optics between projector units, the output of any one tile typically does not match the color and intensity of its neighboring tiles.

Additionally, most tiled displays often occupy a great deal of space. In order to see the entire display area, the viewer must either observe from a long distance from the display, or must step closer and walk from side to side to "pan" over the image tiles.

This project attempts to address these points primarily through the development of:

• Uniform tile color by using a shared light source and fiber-optics for light distribution. The distraction of tile-to-tile color differences will be minimized. Scientifically meaningful color maps will make observations of visualizations more trustworthy.

• Higher-density tiles by using more tightly packed optics packages. Users will be able to view the entire display within their primary field of view and yet can still focus on detailed areas of interest without changing their physical viewing location.

NOTE: Throughout this web page, you may click on the thumbnail images to view larger versions of the images.

Scale

The smaller tile footprint of the HDD system produces a more workstation-scale workspace. It enables users to sit at a standard work table and use a traditional keyboard and mouse for control. Generally, no significant shift in work habits are necessary.

Here's the conceptualized view of the display (furniture is optional!):

Perspective View

Top View

Front View

The real thing

Uniformity

The three primary components of the system which help to achieve tile-to-tile uniformity include a common light source, fiber-optic cables/splitters, and an optics package for each tile (See figure "HDD Optics").



Here's a set of photos of the primary optical components of the system which help to achieve tile uniformity:

Light Source	Dicroic Filters	Fiber-optic cables/splitters
Front view of one optics module	Rear view of optics modules

A spectral photometer was used to sample light at the critical points of the optics path.


White Light Source


Red Light Output


Green Light Output


Blue Light Output

Images

Here are some photos of the HDD system in action:

10-Point gray ramp on CRTs	HDD gray ramp	HDD red channel	HDD green channel	HDD blue channel
777 cockpit on CRTs	CRTs (low ambient)	777 cockpit on HDD
Orion Nebula on CRTs	Orion Nebula on HDD
Atlantis Simulation	Test Pattern	White Field
Before screen enhancement	After screen enhancement

HDD Team

I was responsible for designing the framing system as well as specifying, purchasing, and assembling all of the equipment required to build the framing structure and mounting systems for SDSC's HDD. I also worked alongside of JVC engineers on virtually all mechanical and optical modifications performed on the projector modules. I also oversaw manufacturing of all components produced by UCSD's Campus Research Machine Shop.

I gratefully acknowledge the support provided by the following individuals:

Bernard Pailthorpe (SDSC)	Project conception and backing
Bill Bleha (JVC)	Project manager and optical engineering
John Moreland (SDSC)	Lead project engineer
Steve Reinsch (JVC) (now Reintek)	Primary optical, electrical, and mechanical engineering (and flying tips!)

Acknowledgements

I would like to thank and acknowledge the following people and organizations for their help:

H. Chihara (JVC)	General Manager, JVC's Digital Image Technology Center
Mark Herald (ANL)	Provided ANL projector positioner hardware design, and framing hardware vendor recommendations
Chuck Charman (GA)	Provided mechanical engineering advice