Are standard optics or custom optics better for a lighting application with an LED light source?
Lighting designers may wonder whether their product requires custom-designed optics or whether standard optics would be sufficient. To answer this question, several factors must be considered:
- Do standard optics meet your needs in terms of light distribution?
- Are you satisfied with the performance and efficiency of this lens?
- Do the dimensions of this lens easily fit into your product?
- Does the method of assembling this standard optic suit you in terms of ease and cost?
- Based on your volumes, is the purchase cost acceptable over the long term?
If the answer to all of these questions is yes, then standard optics are probably the obvious solution to your need.
On the other hand, if you answer no to even one of these questions, it may be wise to turn to a custom lens.
Light distribution is the primary function of your lamp. It is easy to find standard optics that provide circular or linear beams in different angles and sizes. On the other hand if you need an asymmetrical beam or one that must meet a specific standard, finding a suitable standard lens becomes more difficult.
Examples of applications that require an asymmetrical beam:
- street lighting
- safety lighting
- bicycle lights
- long distance signaling lighting
- architectural lighting
- medical lighting
- light guides
- variable beam lighting
- advertising lighting
- and more
The “Rayset”: An essential parameter to consider
What also makes research difficult is that each LED model has its own light emission. The “rayset”, which describes how each ray comes out of the source, is specific to each LED model—kind of like fingerprints. An optic may work very well for a certain LED model, but will not do so or will do so with losses for another LED model of equivalent size and power. This can therefore limit your choice of manufacturers and LED models and could prevent you from accessing better prices.
Other reasons to consider a custom optic:
If your product imposes dimensional constraints with, for example, limited space, or if you are looking for a particular beam or optical aesthetic, turning to a custom-made optic makes sense. In this way, we can develop a design specific to the LED you are going to use while maximizing efficiency and giving a unique look to your product.
Efficiency mainly refers to the ratio of lumens emitted by the optics in the desired beam area compared to the full lumen output emitted by the LED. Standard lenses can lose 30% to 80% more lumens than custom lenses—even products that claim to be efficient. Hence the value in using a custom optical design.
The method of assembling the optics is also important. A custom optic can limit the number of components by integrating a mechanical part of your lamp such as a joint, for example, or reduce assembly time with judiciously placed clips. This can translate into significant savings in the long run, depending on production volumes. When designing optics, we are able to simulate the influence of these additions on photometry and remove or reduce them if necessary.
Development and purchase costs are critical parameters when investing in the development of a lamp. The expected sales volume for the luminaire is the primary consideration.
Suppose you have three possible scenarios:
- The first is a 100% standard solution with a lens at $2/part.
- The second is a $10,000 investment in a mold manufactured exclusively for you with a $1.50 part price.
- The third is a $25,000 investment in a mold and optical design with a $1.00 part price (more cavities in the mold and a design reworked to reduce the part price).
The graphs above show the point at which a scenario becomes financially more beneficial.
After 20,000 optics, solution 2 becomes more affordable and after 30,000 optics, solution 3 is the most attractive.
Depending on the characteristics of your LED source lamp, custom-made optics can make a major or even essential contribution to the success of your luminaire in a competitive technological market. Furthermore, at a certain sales volume, a custom lens allows you to reduce the cost of your product compared to ones using standard optics.