![]() ![]() Number of LEDs per lens: The lens can be designed for a single LED or for an array of LEDs. When multiple LEDs are used, diffusion can also offer a more uniform light output. Clear lenses provide a crisp-edged beam of light while a diffused lens has a softer edge. Wide beam angles have a larger coverage for wide area lighting. Narrow beam angles have a tight beam of light and are ideal for spotlights. ![]() Lenses and reflectors can be used to create the desired beam angle. In order to get the lighting effect that best matches the desired result, lighting designers need to consider the following points.īeam angle: This is the angle over which the light is distributed. Lens holders can be used to enhance performance and they are also much easier to install than a standalone lens. LED optics and holder kits contain both the LED reflector and lenses with a holder. With Chip-on-Board (COB) arrays or emitters, LEDs emit light over such a large area that the only real solution is to surround them with a reflector. When compared to TIR, reflectors are easier to implement and cost much less to manufacture. They typically work such that the lens directs light from the centre of the emitter to the reflector, which then sends it out in a collimated and controlled beam, whether narrow or wide. They may incorporate built-in features for attaching them to the LED or a circuit board. They can be solo lenses, or produced in arrays for use with multi-die LED sources. ![]() TIR lenses are typically cone-like and are usually rotationally symmetrical. Glass lenses for the LED quad 32° TIR array These lenses use a refractive lens inside a reflector to control LED light spread efficiently. TIR lenses ensure more control, particularly with high lumen-density light sources. It is best used with tight, narrow beams and does not work quite as well when the goal is wide diffused light. TIR optics was initially used for outdoor applications but nowadays, is also used with indoor lighting. This means that a good portion of the light will stray wide off the intended target, creating glare, and this is where TIR optics is required. The downside to reflectors is that the vast majority of light rays coming from the central emitter pass through the LED light source without even hitting the reflector. In terms of cost and ease of manufacturing, reflectors are hard to beat but they offer less control than LED lenses. The metallised surfaces can achieve high reflectance, although a lens ensures superior beam control. A typical reflector comprises a polycarbonate moulding with a metallised reflective coating. Some reflectors contain a sub-lens, for additional control of the light. They collect and disperse the light depending on their shape. This enables them to create a range of lighting effects. LED reflectors are smooth, multifaceted inside, and come in different shapes. Apart from this, additional surface treatments can be applied to shape light distribution. The lens directs light from the centre of the source to the reflector, which then sends out a controlled beam in whichever direction it is designed to. They come in various shapes and sizes-for example, round, square and hexagonal. Various properties of LED lenses enable the desired lighting effect and precise control over the beams of light. Lenses are designed for use with single or multiple LEDs like LED modules or strips. Reflectors and TIR optics are used for this purpose in many different applications, and both choices have advantages and disadvantages. Choosing the appropriate optics or lens depends on the application. Secondary optics is not only made to collimate the light, but is sometimes also used to improve colour uniformity and light distribution within the targeted area. The secondary LED optics takes all the light within a given bulb or fixture, and magnifies the intensity towards the target, based on how the optics is designed. There are four types of secondary LED optics-lenses, reflectors, TIR (total internal reflector) optics and holder kits. To alter the beam of light coming from the LED source, lighting fixtures require at least some type of secondary optics. The light from an LED’s primary optics is too broad for most applications, and lacks intensity over a distance. ![]()
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