LED optical lens material

To understand how LED lenses are produced, first classify LED lenses.

 

First, LED lens (by material) classification

 

1. Silica gel lens

A, because silica gel has high temperature resistance (it can also be reflow welding), it is often packaged directly on the LED chip.

1. Generally, silica gel lens has a small volume with a diameter of 3-10mm

 

2. PMMA lens

A, optical grade PMMA(polymethyl methacrylate, commonly known as acrylic).

B, plastic materials, advantages: high production efficiency (can be completed by injection molding, extrusion); High transmittance (about 93% when 3mm thick); Disadvantages: Temperature cannot exceed 80°(thermal deformation temperature 92 °).

 

3. PC lens

A, optical grade Polycarbonate(PC) Polycarbonate.

B, plastic materials, advantages: high production efficiency (can be completed by injection molding, extrusion); Light transmittance is slightly lower (about 89% when 3mm thickness); Disadvantages: Temperature cannot exceed 110°(thermal deformation temperature 135 °).

 

4. Glass lens

Optical glass material, advantages: high light transmittance (3mm thickness of 97% penetration), high temperature resistance; Disadvantages: large volume, heavy weight, single shape, fragile, mass production is not easy to achieve, low production efficiency, high cost. However, the current price of such production equipment is high, it is difficult to popularize in the short term. Besides glass from PMMA, PC material brittle faults, still needs more research and exploration, with the improved technology can now implement, only through a coating or steel processing to improve glass non-friable features, although through the processing, the light transmittance of glass lens will be reduced, but still could be far greater than ordinary optical plastic lens effect of pervious to light. So the prospects for glass lenses are much wider.

　　

Second, LED lens (application) classification

 

1. Primary lens
2. A. the primary lens is directly packaged (or bonded) on the LED chip bracket, and the LED becomes an integral part.
3. LED chip theoretically emits 360 degrees of light, but in fact the chip can be fixed and packaged on the LED bracket, so the maximum luminous Angle of the chip is 180 degrees (there is also a small residual light in the range greater than 180 degrees), and there will be some stray light on the chip. In this way, all the light of chip can be effectively gathered through a single lens and different light outlet angles such as 180°, 160°, 140°, 120°, 90° and 60° can be obtained. However, the light outlet efficiency of LED with different light outlet angles is different to some extent (the general rule is: the greater the Angle, the higher the efficiency).

C, primary lens generally use PMMA, PC, optical glass, silica gel and other materials.

 

2. Secondary lens

A, secondary lens and LED are two separate objects, but they are inseparable in application.

1. The function of the secondary lens is to refocus the LED light source's luminous Angle into any desired Angle between 5° and 160°. The distribution of the light field can be divided into circle, ellipse and rectangle.

C, secondary lens materials generally use optical PMMA or PC; Glass is optional in special cases.

 

Third, LED lens (by specification) classification

 

1. Penetrating type (convex lens)

A, when the LED light through the lens of a surface there is a curved surface (double convex) light refraction occur and concentrated, and when to adjust the distance between the lens and the LED will change when the Angle (Angle is inversely proportional to the distance), through the design of optical lens flare will be very evenly, but because of the limitation of lens and lens diameter model The light utilization rate of LED is not high and the light spot edge has obvious yellow edge.

B, generally used in large Angle (above 50°) spotlight, such as desk lamp, bar lamp and other indoor lighting;

 

2, folding reflection type (cone or cup type)

1. The lens is designed to capture light through the front, and the cone surface can collect and reflect all the side light, and the overlap of the two rays (the same Angle) can get the most perfect light utilization and beautiful spot effect;

B, can also make some changes on the surface of the conical lens, can be designed as mirror, frosted surface, bead surface, stripe surface, thread surface, convex or concave surface and so on to get different spot effect.

 

3. Lens module
4. Multiple single lenses are molded into an integral multi-lens, which can be designed into 3-in-1, 5-in-1 or even dozens of one-in-one lens modules according to different requirements; It is also possible to combine two separate lenses through a stand.

B, this design effectively saves production costs, realizes the consistency of product quality, saves the space of the lamp mechanism, and makes it easier to realize the characteristics of "high power".

 

Lens materials and production

 

1, LED lens as an optical level of the product, light transmittance, thermal stability, density, refractive index uniformity, refractive index stability, water absorption, turbidity, the highest long-term operating temperature and so on have strict requirements. Therefore, the lens material must be selected according to the actual situation. In principle, choose optical PMMA. If you have special needs, you can choose optical PC. Currently, the material of Mitsubishi PMMA is the best (VH001 is often selected brand).

2, must be equipped with ten thousand level or higher level of dust-free workshop, operators must wear anti-static clothing, wear finger covers, wear masks and other anti-static dust measures, and regularly to the workshop to do inspection and cleaning.

3, there must be professional optical injection molding machine such as Toshiba, DeMag, Haitian, Zhenxiong and other brands of injection molding machine, and strict control of injection molding process to get qualified products.

4, product inspection: no bubble, no sag, no shrinkage mark, no flow lines, no crescent; Shape accuracy; Surface roughness Ra< 0.0002.

5, the product must be packed with anti-static dustproof PVC, and must be completely sealed packaging, storage must be strictly controlled temperature and humidity, and it is best not to store more than one year.

 

From the above design and production process of LED lens, the seemingly simple LED lens has very high requirements on software and hardware from design to finished product, which also causes the price difference of LED lens in the market. From the bright prospect of LED lighting popularization, lens as a necessary part of LED lighting, the market prospect will be better and better. Dongguan Xiangshun Optics Co., Ltd. adopts PMMA material from Japan and strictly follows the production process to produce LED lens of high quality for you.