Projector vs. Reflector - What's the difference?
When upgrading to HIDs and researching how to go about installing your kit, you'll often come across many debates about projector housings and reflector housings and how they affect an HID upgrade. There are a few dominant opinions about this topic on the internet that are both conflicting and incorrect. Let's dispel the myths, get the facts straight, and help you determine how best to improve your vehicle lighting experience.
Biggest Myth: "Reflector housings are not made for HIDs"
Unfortunately, for all the naysayers out there, this is not a true statement. When HIDs were first introduced to the car market in the late 90's, they all came in a reflector housing. Case in point, the 2001-2003 Acura CL, 2001-2003 Lexus IS, GS, and LS series. Each of these vehicles used a D1/D2 series HID bulb in a reflector housing that controlled light output. These housings were designed with HID light output in mind and were designed with "glare caps" placed over the bulbs to control how light was emitted. Today, many manufacturers have adopted this type of "Glare Cap" for their own halogen housings, making them comparable to the above mentioned vehicles when converted to HID. The basis of the myth that reflector housings were never meant to be used with HIDs stems from the improper installation of HID kits in older vehicles that do not control light well and are not capable of minimizing glare from the additional light to oncoming traffic. This is not to say that all reflectors work well with HIDs; that would also be a false statement. Some reflectors work better than others and you just don't know how it will perform until you try.How exactly does a Reflector work vs a Projector Lens based headlight system?
Projector: From the light source, light bounces inside an elliptical housing before escaping to a concave lens that straightens out the light path directing each beam in the same uniform direction. This provides better lighting because light output is more tightly controlled and all light is directed through the concave lens. You will also notice a shield in a projector lens that blocks light from illuminating the top half of the light pattern. This blocking of light is most commonly known as the light cut-off and is responsible for the sharp beam pattern associated with HID lighting. A projector lens wastes less of the light source and provides more beams of light pointing in the right direction over reflector based lighting.
| Traditional Reflector Housing Light Path | Projector Housing Light Path |
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The light output of an HID system in a reflector based housing is entirely dependent on the design and manufacture as each housing uses different angles and shapes to achieve optimal light output. This is because the size of the reflector housing typically changes to match the profile of the vehicle. With new vehicles on the road today, reflector housings actually control light with both halogen bulbs as well as HID bulbs extremely well with the inclusion of what's known as an Anti-Glare Cap, that limits light output and cuts down on stray light patterns. See the below photo to see an example of the Anti-Glare Cap, and light output of an HID system in a reflector housing + Anti-Glare Cap.
2011 Hyundai Elantra HID Output using a Halogen Based Reflector Headlamp With Stock Anti-Glare Cap
