Head up Display

Dept. ECE 1

ABSTRACT

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, highresolution 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

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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.

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CONTENTS

INTRODUCTION 4

PRINCIPLE 7

WORKING 13

ADVANTAGES 19

APPLICATIONS 20

CONCLUSION 30

REFERENCE 32

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INTRODUCTION

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

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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

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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-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.

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PRINCIPLE

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 headup 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

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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:

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

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and weight of the display system can be much greater than in the

other type which is:

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:

The display element is largely transparent, meaning the

information is displayed in contrasting superposition over the user's

normal environment

The information is projected with its focus at infinity. Doing this

means that a user does not need to refocus his eyes (which takes

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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

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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.

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(a)

(b)

(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

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WORKING

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

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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.

Projection methods

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.

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Depending on the application and cost and size requirements,

we can use single color or multiple low-power solid-state lasers, laser

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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

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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.

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Display using CRT

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ADVANTAGES

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

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APPLICATIONS

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

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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

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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

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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 eightwheel light-armored vehicle, can view its onboard

battlefield computer with a helmet-mounted daylight-readable display.

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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.

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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:

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)

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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[1] (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.

In the James Bond story Licence Renewed, Bond's car, a Saab 900

turbo, was fitted with a HUD.

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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,

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SAN JOSE, Calif. — 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.

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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."

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CONCLUSION

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

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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.

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REFERENCE

www.wikipedia.org

www.microoptical.com

www.iec.org

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HEAD UP DISPLAY

BHAVIK TP S7 EC

NO.9

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ACKNOWLEDGMENT

I would like to place on record my deep sense of gratitude to

Mr.PURUSHOTHAMAN Head of Department of Electronics &

communication, V i ma l J yo t h i En g i nee r in g C o l l eg e for his valuable

help and guidance in carrying out the seminar.

I also thank all the staff of The Department Electronics &

Communication for their assistance and encouragement through out the

course of the seminar.

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

seminar.

Above all I would like to thank God for His abundant grace upon my seminar.