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Tuesday, 13 December 2011

Projector Headlights

Headlights - Focussing on projector headlights.
                                                 
I hope many people are familiar with projector headlights. Generally a headlight serves an important purpose to provide better illumination of road. Headlights are evolved from time to time. The first headlights used in automobiles before the invention of light bulbs were acetylene  lamp or torches since they are resistant to wind and rain. Slowly with the advancement of technology after the invention of electric bulbs the headlights for automobiles are also evolved.




The first type were ordinary bulbs encased inside a reflector to focus the beam exactly on the road without scattering. Those headlights are not precise in focusing the beam for greater dimensions.


The evolution of these conventional headlights occurred by using higher wattage bulbs and better design. Even today many of the automobiles are equipped with these conventional systems for lighting up the night.

The latest innovation of headlight technology include projector headlights, which uses a combination of different type of  bulbs as the source of light. In order to understand the latest headlight technologies we have to know about the different types of the bulbs used on these lighting systems.

At present three types of bulbs are used so far, they are
  • Halogen bulbs.
  • HID (high Intensity Discharge) bulbs.
  • LED(Light Emitting Diode) bulbs.

Halogen Bulbs



A halogen bulb is a bulb which lights up like an ordinary tungsten filament bulb, which is similar to a normal household bulb. These bulb produce bright light due to the type of halogen gas like xenon filled inside it. It has a stronger filament and last longer than an ordinary bulb.

HID (High Intensity Discharge) Bulb















A HID bulb produces a high intense light created by an electric arc generated by an high voltage discharge. This bulb do not contain any filament. The electric arc is produced as a result of a ballast system. It creates a very intense light through the gas filled inside it. This works according to a CFL (Compact Fluorescent Lamps) used in our home as power savers.

The HID Ballast System

The ballast system is responsible for the production of high voltage discharge for the HID bulb to function. Without this component the HID bulb do not function or glow at normal voltages. The ballast system provides 600 volts to start the HID bulb instantly. The HID bulb is similar to the sodium vapour street lamps used in roads and streets. (sodium vapour lamps takes longer starting time).

A Bi-xenon System

Nowadays many automobiles are eqipped with Bi-xenon headlights, many don't know what they exactly mean. A Bi-xenon headlight is a single HID bulb which operates at two modes or two different beam patterns. HID high beam and HID low beam.




The HID Bulb can be fully functional as HID kit which consists of a HID bulb, ballast system and connecting wires






The HID kits are expensive. For a branded product like Philips the cost is close to 8500 INR* .


LED (Light Emitting Diode) Bulbs



The LED are the latest technological innovations here. As we all know LED's are thin layer of semiconductors which are used in series to manufacture an LED bulb.  Primitive LED's were inefficient and wasted power. Nowadays this technology has improved very much to produce bright light with less power consumption and longer life. But this technology has not been developed to match itself with the brightness of HID and Halogen bulbs.

These type of bulbs are used in both ordinary headlights as well as in the projector headlights for automobile lighting.



Ordinary Headlights

The ordinary headlights are the conventional headlights used in all type of automobiles. This system consists of a bulb and a reflector to focus the beam of light.


As we see here is a bulb enclosed by a reflector. The light bulb produces light and the reflector focuses the light.  This system is very simple and a good design of reflector provides better headlight characteristics.


CB Unicorn Dazzler's Headlight


Projector Headlights




A projector headlight is similar to a cinema projector. The projector headlight  projects the light to greater dimensions and distance accurately without beam scattering when compared to a normal headlights. It consists of lens and the light source, (For example consider a HID bulb here as source). The light source and lens are fixed at a particular focal length for better projection of light.














The projector system is somewhat complex one when compared to a conventional headlight system. The high and low beam modes are controlled by a solenoid system if the headlights are not Bi-xenon type. The lens in projector headlight  focus light beam to larger distances providing better visibility when compared to normal headlights.


Projector headlight on a car

The latest and advanced automobiles are equipped with projector headlights. The pulsar 220F is the only Indian bike to use a projector headlight in stock model. The new Thunderbird from Royal Enfield is a latest addition.


The advantages of using projector headlights are numerous, They are well suited for driving in highways since they provide better visibility for larger and longer distances without scattering of light. Any type of bulb can be used in both type of systems for automobile whether its a normal headlight or a projector headlight..


Yamaha R-15 Using a HID Projector headlight