Information systems on the windshield are still very scarce usual in our cars, but some pretty popular models and not very expensive, and equip a basic HUD system, but functional (such as the Toyota Prius), but usually it is that is an optional feature and rather expensive or luxury models. However little too little different manufacturers are betting on this system and it is likely that within a decade is much more widespread. The advantage of the system is clear: to view critical data while driving front line of our eyes, without requiring depart view of the road or half a second.

Start of operation of a HUD
HUD, as many of you know, means Head-Up Display, ie a display (a “screen” if you prefer) you can see with your head, or look away from the horizon. He was born as such in military aviation, to add relevant flight information and objective look on glass cabin. It is based on the beginning of reflection of light on a glass. So it’s basically a projection system for this. Logically thinking as it usually does not result in consistently sharp and contrast images, so some other factors are often added to the equation. One is to increase the reflectivity of the support, for example by making this is somewhat more opaque and dark (for example, a tinted glass).

At other times it is projected on a specific sheet adhered to glass. Another approach (the most effective) is to use the effect of polarization, if the light projected is polarized, and the surface on which it is intended also is the (with a surface treatment) will be caught (will not pass through the glass) and behave as an opaque surface, but only for light that is emitted in a certain direction, letting the light that comes in other directions (hence it is still possible see outside through the glass).

Types Militarily two types of HUD developed: Fixed (information on the glass cockpit). The helmet, called HMD, for Helmet Mounted Display (showing the information in your own visor or . in a lens in front of one eye, supported by a side arm) Parts A HUD system consists therefore of three main parts: The combiner (i.e. the surface on which the image is projected).

The projector (generated image and toward the combiner). The computing unit (which processes data from different sources and arranges for projection). Generating image The image, digits or symbols to be screened on glass, can be generate multiple ways . Initially were generated with a small screen CRT (cathode ray tube) as reflected in a mirror and thence to the windshield .

Solid light sources were also used as the LED (modulated by an LCD) is may employ an optical waveguide that generates the image directly on the combiner (based on the operation of the optical fiber). A scanning laser can also generate images directly on a transparent surface. Lately also be used transparent LCDs or OLED.

HUD as factory equipment As I said, some models of cars already equipped, either as standard, either as an option, an information system on the windshield. Typically, the data is projected ahead of the driver to a height above the instrument panel. Hidden from the eye of the driver, there is a gap in the visor that covers the instrument panel on the projector to generate the image on the windshield is located. In the windshield can be noted, as the light, and if you have a good eye, a small box with a touch tone or slightly different (is the specific area of the combiner).

Today the projection is usually done in monochrome (in a single color without shades or degraded) but starting to show up systems that combine three or four colors. The information displayed does not always coincide according to the manufacturers. The minimum is displaying the speed, but also usually shows a schematic counter, witnesses or changing lights, and even GPS directions browser.
It is considered that it was General Motors in 1988, the first manufacturer to implement a HUD system in a car, and incorporate one color in 1998 C5 Corvette. Toyota, Lexus and Honda also have several models and Citroën (in C6), Audi or BMW (increasingly models, 5 Series, 6 Series, X3, X5). The French manufacturer Peugeot has chosen a HUD system slightly different from these other brands, instead of projecting directly onto the windshield, does so on a small translucent polycarbonate panel behind the dashboard, which can be hidden if desired (it is retractable).
I could not tell which of the two options is better. The panel system often allows nitride viewing the pictures, but the edges of this can make the view change in approach between the data displayed and the horizon, more visual fatigue may occur. By the time most manufacturers (including Citroën, partner Peugeot) opt for projected directly onto the windscreen. Both systems allow you to adjust the brightness of the projected image, either manually or automatically (with light sensors) conditions outdoor lighting, to see the text clearly whatever the circumstances. In case you are curious to see operating system retractable panel Peugeot here’s this explanatory video. HUD as an accessory (or gadget)If you would like HUD in your car, and there was not even an option when you what you bought, do not worry, you will always be able to buy one of “removable”.

There is growing quite varied choices on the market (though still not all sold in Spain), and also some brands are investigating quite interesting projects that may see the light within a few years. Valeo Speed ​​Visio costs about 100 dollars and is a very basic and simple solution.

The device is placed on the dashboard (and yes, you must connect the speedometer to know the speed) and displays the digits by simple reflection on the windshield (hence on the screen upside seen in mirror mode). The screen has LED backlight. To display it requires a workaround, you must attach an elliptical black film on the windshield (which will work almost like a mirror) where we want to see the image, aligned with the device. Just show the speed and maximum speed alerts (to be set manually).
In this case it is a GPS special little browser, the image that normally would be directly on a LCD screen in this case is reflected in a mirror, and the mirror image in turn is reflected in the windshield. Image has various colors and brightness of 13,000 cd / m², so the manufacturer claims is properly even with plenty of sunshine. Without being the windshield prepared for projection, without adding any adhesive sheet in it, I have the feeling that would not always as good as we would like. To handle a satellite knob is pushed several buttons on the steering wheel.
This is another GPS navigator that allows project data onto the windshield; he spoke in his day he Engadget. It consists of two parts, the browser itself, with its color touch screen 5 “, which is attached to the windshield (like any other conventional GPS) and a unit that is placed on the dashboard and reflects on the windshield, monochrome, schematic signs. Not connected to the speedometer, simply shows the maneuvers of GPS (again say the same as before on visibility with plenty of sunshine).

Pictured is a very clean installation, but if we remember that it is a GPS that you can take anywhere, you should know that in reality several cables appear, the power (cigarette lighter) and data between the projection unit and base unit. Pioneer Network Vision HUD This system also spoke at Engadget. It really is a projection system that can connect to any Android device, which uses a scanning laser shows directly onto the windshield images, such an advanced mobile phone.

The projected information so it could be anything, depending on the application that is running on the Android device, could be the GPS navigator, an incoming call or webpage. This projection allows visualizing complex images and color. The data transfer between the device and the projector will do for wireless Bluetooth.

For now is just a prototype, but it seems a very promising system, which could well integrated into the car, or it could be an accessory to acquire a posteriori. According Pioneer could be marketed in 2012. Apart from this brief review, it could also talk about some HUD iPhone app, so suffice to pose this on the dashboard, and reflect the image of the display on the windshield. Sorry to say it does not look very good, especially in bright light (in this case is that almost nothing is visible).
All indications are that the cars will be increasingly multimedia and digital integrated multifunction devices (GPS browser, Internet in the car, phone, etc.) and that the best element will display the windshield. It is likely that this much more information than just the rate is projected. Even it is proposed to synergize these functions augmented reality, whether to improve security, whether to increase information.

For example, using cameras to capture what happens in reality, they may accentuate the lines marking the lanes of the road, can be maintained on the windshield the maximum speed limit on that stretch, or may warn of the presence of pedestrians or bicyclists near our path.
Associated with GPS navigator, you can display on the windshield that are near a gas station (reminding us that we are already booking) or that there is a traffic jam on the road in which we are few kilometers later, an alternative route.  Audi, with its Aida 2.0 system, is also investigating about this, but also proposing a kind of three-dimensional holographic projection, maps and routes browser, and other data related to augmented reality, as events, offers, menus, etc.
An example, driving our car we passed a restaurant, and on the windshield we are informed of the culinary specialty of the day. Another example, we passed a theater and we designed the poster for the work that is being rendered. Speaking of project information onto the windscreen must not forget something important, like anything else, the excesses are usually negative. So we should not fall into giving such information, at any time and on any subject, as to distract the driver, or saturate a way to increase their fatigue at the wheel.
NOTE: Of the infrared vision systems (which can be projected on the windshield, or displayed on a screen) I’ll talk another day.