VS - Lighting Systems - Lighting - 998542

13. High and low beams optical systems

13.1. Parabolic type In many parabolic reflector designs, both high and low beam are produced in a single reflector using a dual filament lamp.

The European way of achieving low and high beam from a single bulb involves two filaments along the same axis in the reflector (typically H4 lamps). To avoid glare, some additions must be made for the low beam. A shield is fitted in the lamp to prevent direct light rays from striking the lower half of the reflector and be reflected upward through the headlight lens, causing glare to other road users. The shape and angular position of the shield defines the cut-off projected pattern.

Reflector (parabolic)

Light bulb

The light-spread on the road is then achieved by patterns in the glass on the outer lens.

More than 40% of the energy produced by the H4 bulb is lost by covering the bulb with this shield.

High beam filament

Low beam filament with mask

Parabolic reflector type - H4 low beam filement

Lens

Parabolic reflectors were basically used in Europe with dual filament H4 lamps.

Headlamp for Opel / Vauxhall - Corsa with H4 lamp and parabolic technology

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