Modern vehicles are equipped with light-signaling devices installed in the front and rear. The formation of the light beam and its coloring in the lanterns is provided by diffusers - read all about these parts, their types, design, selection and correct replacement in this article.
What is a tail light diffuser
The rear lamp lens is an optical element of the rear lighting devices of vehicles, redistributing (scattering) and/or coloring the light flux from the lamp, and ensuring that the characteristics of the rear lamps meet the requirements of the standards.
Each vehicle, in accordance with the standards in force, must be equipped with external lighting devices for various purposes, located at the front and rear. At the rear of cars, buses, tractors, trailers and other equipment there are lighting devices that ensure safety: direction indicators, brake lights, parking lights, parking lights and a reversing signal. These devices are made in the form of separate or grouped lights, the necessary characteristics of which are provided by transparent parts - diffusers.
The rear light diffuser performs several functions:
● Redistribution of the luminous flux from the lamp - the light from the point source (lamp) becomes evenly scattered over a certain area, which provides better visibility of the fire from different angles;
● Painting the luminous flux in the color regulated for each light;
● Protection of lamps and other internal parts of lamps from negative environmental factors and mechanical influences.
If the diffuser is damaged, the information content and functions of the flashlights may be impaired, so this part must be replaced in a short time. And in order to make the right choice, it is necessary to understand the existing types, designs and features of diffusers.
Design and types of rear light lenses
Structurally, any diffuser of the rear lights is a cover made of transparent and mass-painted plastic, which is mounted on the lantern with screws and through a sealing gasket, covering lamps and other parts. Diffusers are usually made of regular or fiberglass-reinforced polycarbonate, transparent and mass-colored.
On the inner surface of the lenses, corrugation is applied to ensure the distribution of the luminous flux in accordance with established standards (±15 degrees in the vertical plane for all lamps, and in the horizontal plane ±45 degrees for brake lights, + 80 / -45 degrees for parking lights, etc.). Corrugation can be of two types:
● Lens trace elements;
● Prismatic trace elements.
Lens trace elements are made in the form of thin concentric rings with a prismatic (triangular) cross-section. Such rings form a flat Fresnel lens, which, with a minimum thickness, provides the necessary light scattering. Prismatic trace elements are individual prisms of small size, evenly distributed over the diffuser.
Rear light diffusers are divided into several types according to their design:
● Separate - individual diffusers for each lamp;
● Grouped - a common lens for the lamp, in which all the rear light-signaling devices of the vehicle are grouped;
● Combined - a common diffuser for the side light and the room lighting lantern;
● Combined - a common diffuser for lamps in which one lamp performs two functions at once, most often a side light and a brake light, combined with a direction indicator.
Currently, separate lights and individual diffusers for them are used extremely rarely, and even on early models of automotive equipment, such a solution can be found only for parking lights. The exception is the reversing lights installed on many domestic cars, including trucks, and trailers.
On passenger cars, the most widespread are grouped lamps with diffusers, divided into a number of light-signal sections of various shapes and colors. Such diffusers can have up to seven zones:
● The extreme one on the outside of the car is the direction indicator;
● The closest to the direction indicator is the side light;
● In any convenient place - a brake light;
● In any convenient place (but most often at the bottom) - a reversing light;
● Extreme on the side of the longitudinal axis of the car is a fog light;
● In any convenient place - reflector (reflector);
● On the side of the license plate there is a license plate light.
Reversing
lamp diffuser Rear position lamp diffuser
Grouped tail lamp diffuser Tractor
combined rear lamp
Diffuser
Often, in such combination lamps, side lamps and brake lamps can be combined on a lamp with two spirals (or on LEDs of different brightness), which provides different brightness of the lights when the car is moving and braking. Also, in modern passenger cars, there are practically no combined light-signaling devices with integrated license plate lights.
Combined lights with appropriate diffusers are most often used on trucks, trailers, tractors and various equipment, as well as on UAZ up to the Hunter model. Such lights are of three main types with different diffusers:
● Two-section with direction indicator and side light;
● Two-section with a direction indicator and combined side light and brake light;
● Three-section with separate direction indicator, side light and brake light.
Two-piece lamps often have composite diffusers made of two halves of different colors, which allows you to replace only one half if necessary. In two-section and three-section diffusers, a retroreflector may be additionally installed.
The different areas of the diffusers are painted in certain colors set by the standards:
● Parking lights - red;
● Direction indicators - white or selectively yellow (amber, orange);
● Brake lights are red;
● Fog lamps - red;
● The reversing lights are white.
Red reflectors are also used in the diffusers.
Grouped, combined and combined diffusers are symmetrical (universal) and asymmetrical. The first can be installed on the right and on the left lantern, and the diffusers with a horizontal arrangement of the light-signal zones must be turned 180 degrees. And the second ones are installed only on their side, so the car uses a set of two diffusers - right and left. All this must be taken into account when buying parts.
The characteristics of the rear lamp lenses must meet the requirements of GOST 8769-75, GOST R 41.7-99 and some others in force in Russia.
Typical design of a two-section flashlight and the place of the diffuser in it
ssues of selection, replacement and maintenance of the tail lamp
Taillights, especially on trucks and tractors, are subject to constant exposure to negative environmental factors, which leads to their turbidity, cracking, chipping and complete destruction. It is forbidden to operate a vehicle with a damaged diffuser, as this may lead to penalties for the car owner. Therefore, this part must be replaced as soon as possible.
Lenses should be replaced only by those types that are used in the lamps, and also correspond to the lamps installed in the lamps (this applies to direction indicators). Here it is necessary to take into account the type and side of installation of the lighting device, and use either universal or designed for this particular lamp diffusers.
Particular attention should be paid to the color of the diffusers and the zones on them - they must exactly comply with GOST. At the same time, direction indicators can be of two types - white or orange (amber), they are used with lamps of various types: white - with lamps, the bulb of which is painted in a selective yellow (amber) color, and orange - with ordinary lamps with a transparent bulb. Today, you can find composite two-section diffusers in which the area under the direction indicator can be replaced with a white or orange part, which allows them to be used with lamps of any type.
Replacing the diffuser is generally quite simple: just unscrew a few screws, remove the old diffuser and gasket, clean the installation site of the parts, lay a new seal, install the diffuser and screw in the screws. To replace the diffusers of the lighting devices of modern passenger cars, it may be necessary to dismantle the entire lantern. In any case, all work must be carried out in accordance with the instructions for the repair and maintenance of the vehicle.
With the right choice and replacement of the diffuser, all the car's lighting devices will meet the standard and contribute to road safety.
Post time: Jul-11-2023