The lens is a common light distribution device of the LED era, without this core light control component, it would feel like fluorescent lamps everywhere, with light being scattered and disordered. The most classic of the standard lenses is the conical lens with most of these being TIR lenses.
What is "TIR"?
"TIR" stands for Total Internal Reflection. It is an optical phenomenon that occurs when light traveling within a medium with a higher refractive index encounters a boundary with a medium of lower refractive index at an angle greater than the critical angle. In this situation, instead of refracting into the lower refractive index medium, the light reflects entirely back into the higher refractive index medium.
The critical angle is the angle of incidence beyond which total internal reflection occurs. The phenomenon is based on the principle that at certain angles, the light cannot pass through the boundary and is reflected internally.
Total internal reflection is commonly used in various optical devices and applications, including fiber optics, prisms, and lenses. In the context of lenses, especially Total Internal Reflection (TIR) lenses, the design takes advantage of this phenomenon to control the direction and distribution of light, providing efficient beam shaping and control.
TIR lens: improving LED light energy utilization
TIR lenses function by collecting and processing light using the principle of total reflection. It is designed to gather light at the front by penetration, and the conical surface can collect and reflect all the side light, and the overlapping of these two kinds of light can get perfect light utilisation and a beautiful spot effect.
The efficiency of TIR lens can reach more than 90%, which has the advantages of high light energy utilisation, low light loss, a small light collection area and good uniformity.
The difference between TIR lens and reflector cup
In the context of LED torches or flashlights, both TIR (Total Internal Reflection) lenses and reflectors are components that play a crucial role in shaping and directing the light produced by the LED. Here are the key differences between TIR lenses and reflector lenses:
1. TIR Lens (Total Internal Reflection Lens)
▲ Design: TIR lenses are designed to utilise the principle of total internal reflection to shape and direct light. They are typically made of transparent materials with a specific geometry to achieve total internal reflection.
▲ Function: TIR lenses can control the beam pattern more precisely than traditional reflectors. They are effective in producing a focused, uniform beam with reduced spill and stray light. TIR optics are often used for spotlights or throw-focused flashlights.
2. Reflector Lens:
▲ Design: Reflectors in flashlights are usually concave surfaces positioned around the LED light source. These surfaces are coated with reflective materials to bounce light in a specific direction.
▲ Function: Reflectors are designed to collect and reflect light outward, creating a more dispersed beam pattern. They are effective for floodlights, providing a wider area of illumination. However, they may not be as efficient in controlling the light's direction compared to TIR lenses.
3. Choosing Between TIR Lens and Reflector Lens:
▲ Spotlight vs. Floodlight: If you want a flashlight with a more focused, spotlight effect, a TIR lens might be preferable. If you need a wider, floodlight beam, a reflector might be more suitable.
▲ Efficiency: TIR lenses are often considered more efficient in terms of light utilization, as they minimize light spill and focus the beam. Reflectors may have some light spill and scatter.
▲ Application: The choice between TIR lens and reflector lens often depends on the intended application of the flashlight. For example, searchlights or tactical flashlights may use TIR optics for a focused beam, while camping or work lights may use reflectors for broader coverage.
Ultimately, the specific design goals of the flashlight and the desired application will dictate whether a TIR lens or a reflector lens is more suitable. Some flashlights even use a combination of both technologies for a versatile beam pattern.
Currently, most of the reflector cups used in torches are made of metal, which requires stamping and polishing processes. The main material of the TIR lens is PMMA (acrylic), which has good plasticity and high light transmittance (up to 93%) and is of course better quality. Other materials include tempered glass, etc.
That's all for today! If you have anything to add, welcome to the comments section to share!
