A head-up display system projects an image directly onto the human retina with low-energy lasers or LCDs. Head-up displays can give the user ' the illusion of viewing a typical screen-sized display hovering in the air several feet away. In principle the technology can provide full-color, highÃ‚Â¬resolution dynamic displays, but in practice the components necessary to achieve the full potential of the technology are either highly expensive. ; Although the technology was invented by the University of Washington in the Human Interface Technology Lab (HIT) in 1991, development did not begin until 1993; the technology still needs much refinement and has only been commercialized in specialized sectors of the display market such as automobile repair and some parts of the military.
The head-up display is highly efficient with respect to power consumption, requiring far less power than the postage-stamp LCD screens used commonly in today's mobile devices. A head-up display uses about a microwatt of power. Since head-up display displays project images directly onto the retina, they provide a sharp, clear image regardless of external lighting conditions. Head-up displays require a fraction of the hardware of conventional display devices, allowing for lighter and more elegant mobile devices, in high demand for today's electronics market. Head-up display shows strong potential to replace LCD screens in cell phones, handheld computers, handheld gaming systems, and eventually even larger computers such as laptops.
Our window into the digital universe has long been a glowing screen perched on a desk. It's called a computer monitor, and as we stare at it, light is focused into a dime-sized image on the retina in the back of our eyeball. The retina converts the light into signals that percolate into your brain via the optic nerve.
Here's a better way: paint the images themselves directly onto your retina, and eliminate that bulky, power-hungry monitor altogether. To paint the images, use tiny semiconductor lasers or special light-emitting diodes, one each for the three primary colors (red, yellow, and blue), and scan their light onto the retina, mixing the colors to produce the entire palette of human vision. Short of tapping into the optic nerve, there is no more efficient way to get an image into your brain.
The advantages, at least for some viewing situations, are overwhelming. If the light was scanned onto only one of your retinas, images could be overlaid on your view of real objects, giving you an animated, X-ray-like glimpse of the simulated innards of something, such as a car's engine or a human body. Alternatively, if slightly different images were scanned into each eye, grippingly vivid three-dimensional scenes could be rendered, with pure, jewel-like spectral colors. Gainers would experience a heightened sense of reality that LCD goggles could never provide, because the laser or LED-based system could dynamically refocus to simulate near and distant objects with utter realism.
Best of all, the system would waste essentially no photons so it would be fantastically very well suited to the low-power requirements of mobile devices. In round numbers, lasers or LED's would use hundreds of times less power than a small LCD screen typically sub notebook or I handheld personal digital assistant. Imagine a cell phone or a PDA with a small, camera-like viewfinder that, by stimulating your retina when peered into, would show you an image rich in colour and detail. the image would appear to your brain as large as brightly lit display screen 65cm away , which could be reconfigured quickly from , say , a traditional boxy 4:3 format to the widescreen 16:9 format .
The forerunners of such systems, known as scanned-beam displays, are just now hitting the market. They're moving into the automotive-service industry to help service technicians keep track of the huge and ever changing reams of engine data precisely where and when they need them-Ã‚Â¬in the service bay, as they are working on a car. This first-generation system, from Microvision of Bothell, Wash., was introduced to auto dealers earlier this year at the National Automobile Dealer Association conference in Las Vegas. Test of the Nomad at the American Honda Motor Co. training center. An in Torrance, Calif., showed that skilled service technicians performed complex repair procedures in 39 percent less time, on average. Surgeons and U.S. soldiers are also testing the system. Offshoots of that technology will pop up in bar-code readers, endoscopes, and digital cameras, where scanned-beam displays provide better image quality at lower power and cost than liquid crystal on silicon and organic LEDs.
Head-up display have now become so compact and lightweight that an emerging use is for displaying information to workers on site locations such as power stations, airports and events. A new breed monocular headÃ‚Â¬up displays (HUD) cater for this application.
These displays are discreet and easy to use and are being used in the field by engineers, security and police forces.
Head-up display utilizes a low powered laser device to literally project a laser image onto the viewer's retina.
We are aware of the harmful effects of the laser and may be wondering about the safety of aiming laser light directly into the eye. To ensure that its device is safe, Microvision applied rigorous safety standards from the American National Standards Institute, Washington, D.C., and the International Electrotechnical Commission, Geneva, derived from years of studying the effects of light on the eye. Laser light can be harmful because its beam is intense, capable of concentrating its power in a tiny area of incidence. This could be a problem if a fixed beam-as opposed to a scanned beam-were allowed to dwell on just one spot. We ensure that the retina is never overw overwhelmed by limiting the power of the laser light entering the eye to about a thousandth of a watt and using a high-reliability interlock circuit that turns on the laser only when the beam is scanning. Furthermore, because this very low-power light is continuously scanned onto the retina, its energy is dispersed over an area hundreds of thousands , of times larger than a single spot of an incident beam.
Head-Up Display, also known as a Heads-Up Display or simply HUD, is any type of display that presents data without blocking the user's view. In civil aviation the HUD is known as a Head-Up Guidance System (HGS).
There are two types of HUD:
Â¢ Fixed- In which the user looks through a display element attached to the airframe or vehicle chassis. Commercial aircraft and motor vehicle HUDs are of this type. The system determines the image to be presented depending on the orientation of the vehicle. The size and weight of the display system can be much greater than in the other type which is:
Â¢ Helmet-mounted, or head-mounted-In which the display element moves with the user's head. This requires a system to precisely monitor the user's direction of gaze and determine the appropriate image to be presented. The user must wear a helmet or other headgear which is securely fixed to the user's head so that the display element does not move with respect to the user's eye. Such systems are often monocular. One use of this type of HUD is in the AH-64 Apache and in the Norwegian F-16 Fighting Falcons.
HUDs have in common the following characteristics:
Â¢ The display element is largely transparent, meaning the information is displayed in contrasting superposition over the user's normal environment
Â¢ The information is projected with its focus at infinity. Doing this means that a user does not need to refocus his eyes (which takes several tenths of a second) when changing his attention between the instrument and the outside world.
The company uses microelectromechanical system (MEMS) devices to scan the beams back and forth and, where appropriate, to mix different colors to produce white light. Because the beam sweeps over the retina instead of dotting it, lines need not be serrated and images need not be grainy. Bright as the picture will seem to the naked eye, it will consume barely a microwatt, potentially saving hugely on battery power. And, by sending light only where it's needed, the system can keep nosy neighbors in adjacent airline seats from snooping on your work (or play). With a sufficiently inconspicuous eyepiece, one might even feign attention to a speech or lecture while, in fact, watching television.
Resolution and Colour Depth, and Brightness:
The overriding design factor for these type of Head-up display is their compactness which means that the resolution of these models is not yet as high as some of the virtual reality Head-up display. Older HUD's offers resolutions starting from 320x240 (qVGA) up to 640 x 480 (VGA) and includes true colour models. They are also available in binocular configurations to give twice the display area. Microvision's Nomad has a resolution of 800 x 600 and is red-monochrome. Colour is not important for many applications where content is mainly technical data and text. Microvision's displays use red laser light. One of their strong points is that they are very bright and can easily be viewed in strong sunlightField of view (FOV)Average human vision covers an area of about 200 degrees horizontally by 150 degrees vertically. FWD FOV figures are typically given as diagonal FOV. That is the perceived angle from one corner of the screen to the opposite corner.
(a) Approx. human horizontal field-of-view (b) Approx. human vertical field-of-view
One of the most important factors for head-up information display is that any text or technical diagrams are clearly legible. These Head-up display are currently not designed to immerse the user with wrap-around images but instead to provide the equivalent of a 'floating monitor' taking up part of the user's field of view
There are just four primary components of a scanned-beam display: electronics, light sources, scanners, and optics. Yet with a modular approach, these simple elements can be combined to yield many different products.
Electronics acquire and process signals from an image or data source, such as a Web page or video camera. The processed signals contain information for the intensity and mix of color that best renders the intended image at each location that will be scanned, in sequence. These values are the individual picture elements-pixels-that make up the image. This information is stored in memory until needed, when the data pass through a digital-to-analog converter that controls the light source. Once the image has been rendered into memory, there is no need to recalculate it unless something has changed. The data can simply be replayed from memory, a feature that can be exploited to cut costs or save power.
In the scanned beam display headset the viewer sees an image when modulated signals from laser diodes sweep across the retina. A microcontroller in the visor selects the image from the view memory and passes it to digital to analog converters. These produce signals that Control lasers - red, green and blue-for a full color display. The modulated light passes to a tiny scanning mirror and then to a pupil expander that allows for eye movement by enlarging the image Next, the images reflected in to the eye and onto the retina.
The most common means by which current HUDs are implemented is to project the image onto a clear glass optical element ('combiner'). Traditionally, the source for the projected image has been a Cathode Ray Tube (CRT), however newer image sources based on micro-display technologies are now being introduced. Micro-display technologies that have been demonstrated include Liquid Crystal Display (LCD), Liquid Crystal On Silicon (LCOS), Digital Micro Mirrors (DMDs), Organic Light-Emitting Diode (OLED) and Laser.
Depending on the application and cost and size requirements, we can use single color or multiple low-power solid-state lasers, laser diodes, or LEDs as the light source. In the case of a full-color electronic viewfinder display on a camera where low cost and power consumption are critical, I modulated red, green, and blue LEDs produce color pixels of varied'intensities to generate a complete palette of colors and shades.
If the light source is the paint, Microvision's proprietary mieroeiectromechanical systems (MEMS) biaxial scanner is the brush that applies the image to the retina. The scanner's main component is a minor 1.5 millimeters in diameter that rapidly sweeps the light beam horizontally to position the pixels in a row, also moving the beam downward, to draw successive rows of pixels. This process continues until an entire field of rows has been placed and a full image appears to the user-quite similar to the process in a regular cathode-ray television, in which the magnetic deflection coils direct the electron beam to scan the phosphor-coated screen. But while a conventional display can create jagged edges on images because the pixels are fixed onto screen hardware, a scanned-beam display has no hard pixels: the continuously scanning beam creates a much smoother image.
For applications in which the scanned-beam display is to be worn on the head or held closely to the eye, we need to deliver the light beam into what is basically a moving target: the human eye. Constantly darting around in its socket, the eye has a range of motion that covers some 10 to 15min. One way to hit this target is to focus the scanned beam onto an optical element called an exit pupil expander. When light from the expander is collected by a lens, and guided by a mirror and a see-through
monocle to the eye, it covers the entire area over which the pupil may roam. For applications that require better image quality using less power, we can dispense with the exit pupil expander altogether either by using a larger scan mirror to make a larger exit pupil or by actively tracking the pupil to steer light into it.
Display using CRT
The head-up display is highly efficient with respect to power consumption, requiring far less power than the postage-stamp LCD screens used commonly in today's mobile devices. A head-up display uses about a microwatt of power. Since head-up display displays project images directly onto the retina, they provide a sharp, clear image regardless of external lighting conditions. Head-up displays require a fraction of the hardware of conventional display devices, allowing for lighter and more elegant mobile devices, in high demand for today's electronics market. Head-up display shows strong potential to replace LCD screens in cell phones, handheld computers, handheld gaming systems, and eventually even larger computers such as laptops
The following applications are where the majority of these displays are used:
Law Enforcement, Medical, Military, Service Technicians, Automotive Technicians, Non-destructive Testing, Security, Test and Measurement, Video production, Mobile Computing, Consumer video.
Head-Up displays were pioneered for fighter jets and later for low-flying military helicopter pilots, for whom information overload was a significant issue, and for whom changing their view to look at the aircraft's instruments could prove to be a fatal distraction.
HGSs have been in use in commercial aviation since the 1970s, and are now in regular use, notably with Alaska Airlines.
Heads up displays have also been incorporated into automobiles, usually as a secondary display for the most important information from the gauges. General Motors was the first to put the Heads up Display into cars in 1988. These early HUD units were made by Hughes Aircraft Corporation, a GM subsidary. One of the first vehicles to receive a HUD was the May 1988 Indianapolis 500's 1988 Cutlass Supreme Pacecar, as well as 50 custom convertible pacecar replicas commissioned by GM.
Since 1988 General Motors offered the Heads Up Displays as an option on the 1989-1994 Oldsmobile Cutlass Supreme, 1989 to present Pontiac Grand Prix, and 1993 to present Pontiac Bonneville, and more recently the Buick LeSabre, Park Avenue and Rendezvous.
During the 90's, Heads Up Displays were an option offered in Nissan models including the Silvia family of cars.
In 1999, Automotive HUD technology made a big quality leap with the Chevrolet Corvette. The new Corvette, which uses a HUD to display vehicle speed, engine RPM, Navigation and more, has proven the HUD to be one of its most popular options.
In 2000 Cadillac Premiered an optional night vision driving system as a secondary aid for drivers. It utilizes a monitor set in the dash that displays a generated night vision image of the road, using an infrared camera
As of 2006 BMW now features the head-up display as an option on their 5 and 7 series vehicles, with more HUDs being anticipated from other European and Japanese OEMs.
As the doctors operate the patient, the surgeons are viewing vital patient data, including blood pressure and heart rate. And in such procedures as the placement of a catheter stent, overlaid images prepared from previously obtained magnetic resonance imaging or computed tomography scans assist in surgical navigation.
Several military units, including the U.S. Army's Stryker Brigade, are using adaptations of the system. The commander of a Stryker, an eightÃ‚Â¬wheel light-armored vehicle, can view its onboard battlefield computer with a helmet-mounted daylight-readable display. This enhances the commander's ability to observe the surroundings, choose the
Optimum path, command the vehicle, and use tactical information advantageously. Other military applications include a series of prototype helmet-mounted displays developed with the U.S. Army and Boeing Co. of Chicago. Currently in the initial stages of flight-testing, the system could be a relatively inexpensive way to provide utility- and attack-helicopter pilots with a digital display of the battle space.
Displays from both MicroOptical and 1Vlicrovision are suitable for outdoor usage and both are capable of connecting to handheld PCs and PDAs. Microvision's Expert Technician System includes a wearable running Windows CE.NET and is tough enough to be used in industrial environments. MicroOptical's displays are often used with wearable computing system. They are also available with video inputs allowing use with DVD players or Camcorders.
HUDs have been proposed or experimentally developed for a number of other applications, including:
Â¢ overlaying tactical information onto the vision of an infantryman (such as the output of a laser rangefinder or the relative location of the soldier's squadmates)
Providing basic information for car drivers, by projecting an image (again, at infinity) onto the inner surface of the car's windscreen. This has been released as a product by a few manufacturers (usually showing a speedometer) but is presently illegal in several jurisdictions (where laws prohibiting driver-viewable TV sets currently include HUDs). HUDs are likely to become more common in future vehicles.
Â¢ In the James Bond story Licence Renewed, Bond's car, a Saab 900 turbo, was fitted with a HUD.
Â¢ providing surgeons with an enhanced view, showing the results of x-rays or scans overlayed over their normal view of the patient, and thus allowing them to "see" structures normally invisible.
might be displayed at once, with the rest being rotated into view using the [ and ] keys. There is also a lot of variance with regards to the display of other information. Some games permanently display all the weapons a character is currently carrying, others rely on a pull up weapon selector. Inventory or storage space may also be permanently overlaid over the screen, or accessed via a menu. Alternatively, only a limited number of items stored in the inventory
The HUD in Metroid Prime is explained as being displayed by the character's helmet.
In order to maintain the suspension of disbelief,
SAN JOSE, Calif. â€ A new head-mounted display (HMD) venture, MicroOptical Corp., will demonstrate an unobtrusive display next month that can be clipped onto or integrated into conventional eyeglasses. A step beyond the latest lightweight, ergonomic headgear, MicroOptical calls its Eyeglass Display the first truly practical HMD.
The HMD arena is due for a dose of practicality, sources said, having failed to move much beyond the heavy, expensive headgear for technicians and maintenance workers who absolutely require a hands-free screen. The crop of miniature-LCD technologies brought to market within the past year is a breath of fresh air for HMDs, however. MicroOptical's design is based on such an LCD, but the company applies the display to the wearable-monitor problem in a novel way.
"The conceptual demand for HMDs is very high but nobody's gotten the ergonomics right," said Tom Holzel, vice president of sales and marketing for MicroOptical (Westwood, Mass.), which will demonstrate the Eyeglass Display at the at the Society for Information Display conference in San Jose, Calif.
Holzel called the integrated version "a featherweight personal display with an appearance nearly indistinguishable from conventional glasses. We can build this monitor into prescription eyeglasses, safety glasses, military goggles, whatever. We just need a couple of millimeters of glass to shoot light into from the side."
As with most hi-tech electronics, head-up displays are set to become smaller and lighter. MicroOptical is working towards a model that will look no different to a normal pair of glasses. In the near future, head-up displays will be available with wi-fi and Bluetooth connectivity, allowing user's to surf the web and check their email on the move.
There will also be devices that will create full colour images that look bigger than a cinema screen, from a tiny head-mounted or handheld device. This will open up applications such as augmented vision and augmented reality.
Car dashboard information could be displayed by such a display, allowing real-time information on the car, traffic and directions, to be superimposed anywhere in the driver's field of view.
Mapping will take on a new leash of life with augmented reality and GPS technology. Users will be able to see a map of their current location displayed right on top of the real thing. This will aid navigation in cities and the countryside, allowing street names to appear on every road and virtual sign-posts to lead you to your destination. Local information such as the nearest police or tube station could be overlayed onto your view along with directions to the nearest cash point or taxi rank.
HEAD UP DISPLAY
I would like to place on record my deep sense of gratitude to Mr.PURUSHOTHAMAN Head of Department of Electronics & communication, Vimal Jyothi Engineering College for his valuable help and guidance in carrying out the seminars.
I also thank all the staff of The Department Electronics & Communication for their assistance and encouragement through out the course of the seminars.
Last, but not the least I would like to thank my parents and friends who encouraged me and gave me the motivation to complete the seminars.
Above all I would like to thank God for His abundant grace upon my seminars.
Â¢ INTRODUCTION 4
Â¢ PRINCIPLE 7
Â¢ WORKING 13
Â¢ ADVANTAGES 19
Â¢ APPLICATIONS 20
Â¢ CONCLUSION 30
Â¢ REFERENCE 32