How to choose the best LED modules?

There are so many LED module suppliers in the market. How to get the high quality, long lasting LED circuit boards at competitive price? As an expert in LED modules for more than 10 years, NKT shares some handy information about how to pick a suitable LED Module with customers having high level of expertise. Our main market is in North America and Europe, so we are more familiar with the standards from these 2 markets. Welcome to email us to share your ideas with us. 

Critical factors for North American Professional buyers: 
a. Luminous efficacy: In order to get rebate, All the LED lighting fixtures need to be DLC certified. The newest standard is DLC 5.1, which requires 140lm/W for some indoor premium products like high bay lights. In order to achive ≥140lm/W, the efficacy of led module/LED PCBA, LED Circuit boards needs to be at least 180lm/W. For most of international LED manufacturers like Cree, Osram, Nichia, Seoul, Samsung, Bridgelux, they all have suitable LEDs to achive this, but this doesn't mean all the players have the same advantages. Among them, Korean branded leds and Bridgelux leds make more economic sense while delivering high efficay. It is reported that Bridgelux is getting more and more popular especially after a series of high CRI LEDs are developed, though not making concession to the efficacy. 
                           
                                        TABLE SOURCE: DLC® SSL TECHNICAL REQUIREMENTS V5.0 & 5.1 WEBINAR
b. Color rendering index: The most commonly used CRI index is CRI 70, CRI 80 and CRI 90. For some outdoor products, CRI 70 is still greatly used because the focus is the lumen output and it is less costly. For the led fixtures using CRI 90 leds, which are normally installed in locations which require to reflect the real color of objects, like jewelry display stores, homes, hotels. In these locations, the goal is to have the feel of comfort, not the shiny, bright light. The downside is it is more expensive. Of course, both CRI 70 and CRI 90 have outstanding advantages and some downsides. How do we achieve a balance between intensity, reasonable CRI and cost? CRI 80 plays the most important role in keeping a good balance, which is vastly used in commercial lighting like LED high bay, LED troffers and they are installed in offices, stores, warehouses, etc. Although most of manufacturers can produce products ranging from CRI70 to CRI 90, when picking a right LED, paying attention to Ra is not enough, R9 is a critical factor for indoor LED Lighting fixtures which requires>0 for DLC 5.1. We have encountered some big companies in China whose high efficacy LEDs don't meet the requirement. 

c. PCB: In the market, most of LED modules use Aluminum board because it has better heat dissipation function and it is less expensive than FR4 and CEM. To ship internationally, there can be two challenging aspects which aluminum PCB has to face. The one is it is heavy, which means the shipping cost can be high especially the international freight has risen to a historically high point. The other one is that exporting to North American and European countries from China could trigger anti-dump taxes and duties on Aluminum products. FR4 PCB is not used on LED lighting products much, the main reason is that it doesn't  have heat dissipation function and it is expensive, so what? Maybe using CEM PCB can be an option. High quality CEM PCB has heat dissipation function and it is light, which helps reduce the freight and it doesn't have anti-dump risk. It sounds like a perfect solution so far. It seems most of big players like Osram, Signify, Trodonics all use this tyep of PCB material. 

Critical factors for European Professional buyers:
a. Efficacy: When new ERP standard was enforced since Sep 1st, 2021, the efficacy has been greatly increased. To meet class C or Class D standard for the LED Lighting fixtures, the efficacy of DC the LED modules should be at least >190lm/W, which requires the most efficient LEDs in the market. NKT uses some LEDs from Seoul Semiconductor and Bridgelux which could help achive the goal.


b. CRI: In Europe, most of high end customers like to use CRI 90 LEDs and the main color temperature they use is 3000k and 4000k. Bridgelux has a series of LEDs with high CRI and high efficacy which could help customers stand out. 
c. L70, L80, L90: L defines the percentage of lumens compared to the initial lumens. Some professional customers need L70, L80, L90 datas for their lighting devices, but more professional lighting manufacturers require B value. The B value represents the fault data at the L data. B10 means that 10% of the LEDs cannot meet the requirements. Therefore, the LB value represents the actual life of a certain hour. L/B is the standard definition of lamp life. For example, 50000h (L90/B10), that is, the time taken for 10% of the product's luminous flux output to drop below 90% of the initial value is 50,000 hours. On the contrary, it means that LED products have a reliability of 90% of the products' light decay less than 10% after working for 50,000 hours. TM21 is an useful tool to provide L70, L90 value based on LM80 report. 

d. Compliance: For AC modules, meeting CE and ERP standard are the key to make a reliable product. In order to meet ERP standard, some watchful factors are as belows, for more detailed information, please refer to page New ERP/Energy Labelling Directive. 
1. Pst≤1
2. SVM≤0.9 is required in the stroboscopic performance test (SVM≤0.4 after September 1, 2024).
3. DF factor

Of course, to pick a good LED Module, no matter it is a DC one or an AC one, a number of other factors need to be considered as well. Maybe it is worth taking a look at the below aspects. 
Eelectrical data: 
DC(direct current) LED modules:  the No. 1 advantage of DC LED module is more efficient, and less risks of shock hazard for products below 50 volts. Please provide operating voltage range, current range, wattage range while communicating with us on designing a high efficacy LED Module. 
AC(Alternating current) LED modules: The AC modules also called DOB(driver on board), which is directly powered by AC 120V (100~140V) / 220V (200~265V). Say goodbye to costly LED driver, so the advantage is more economic and it is also more convenient.  PSTLM, SVM, Displacement factor need to be tested in order to meet new ERP standard. 
Photometrical data: 
Luminous efficacy: High enough efficacy in order to meet DLC and ERP standard.
Color rendering index Ra: 
Light color: White, RGB, Red, Green, Amber, UV
Color temperature CCT: 2700k, 3000k, 3500k, 4000k, 5000k, 6000k, 6500k
Colour consistency:  MacAdam 3 LEDs insures the consistency
Useful luminous flux: 
Light technical data:  starting time, warm-up time.
Dimensions & weight:  Length, width, PCB thickness, diameter, weight, which are to make sure the LED modules fit your housing/fixtures.
Temperatures & operating condictions: Performance temp, maximum temperature at tc tect point, ambient temperature range.
Lifespan: Number of switching cycles, LM XX BXX life time, LMF. lumen maintenance factor
Certificates & Standards:  Check the led module if they can meet any certifications like ETL, ERP, CE, RoHs, ENEC, UKCA, VDE, what type of protection and what energy efficiency class.
Logistical data: Packaging information, HS code.