LED lighting is fast replacing traditional incandescent and fluorescent lighting due to benefits like high energy efficiency, long life and design flexibility. At the heart of an LED lighting product are the LED chips which provide the illumination. Choosing the right LED chips is crucial for achieving the target light output, efficiency, color characteristics and reliability.
This article discusses how to select appropriate LED chips for lighting design including parameters like power, luminous efficacy, color temperature, CRI index and thermal management. Read on for practical guidance to pick optimal LEDs for your lighting application.
The main parameters that characterize an LED chip are:
Primary aspects to consider when choosing LED chips for lighting include:
Let&#;s look at some of these aspects in more detail.
Available LED chip power ratings include:
Higher power LEDs produce greater luminous output. But the increased heat needs thermal management.
For most general lighting like bulbs, downlights and strips, mid-power 1W to 3W LED chips offer a good compromise between light output and easier thermal control vs high power chips.
But specialty lighting like high bay lighting may use higher 5W-10W LEDs. While battery powered flashlights can use tiny 0.2W-0.5W chips.
The lumen rating of LED chips depends on the power and efficacy. Various luminosity bins are available for each LED chip ranging from low to high lumens.
Typical lumen output for various power LEDs:
Select chips with lumen output that meet the application&#;s illumination needs. Combine multiple lower lumen LEDs for higher brightness.
Higher efficacy or lumens/watt improves lighting energy efficiency. LED chip efficacy has increased enormously over the years due to technology improvements.
For a given power rating, choose LED chips with the highest efficacy within budget. This maximizes light output vs power consumption.
Color temperature determines the visual color tone of white light &#; from warm white to cool white.
Common white LED color temperatures:
Warm white is commonly used in homes for cozy lighting. Cool white is preferred where brighter illumination is needed. Select color temperature depending on lighting ambiance needed.
The Color Rendering Index (CRI) indicates how accurately colors are displayed in the light.
Aim for LED chips delivering 80+ CRI for quality lighting applications. chips with CRI 90+ can provide near natural color rendition.
LED chips last much longer than traditional light sources. But over time, light output gradually declines due to phosphor degradation.
Match the LED chip operating life to the target product lifespan. Also factor in ambient temperature which affects LED lifetime.
LED chips generate significant heat. Operating at high temperatures lowers light output and shortens lifetime. Effective thermal management is vital.
Proper thermal design greatly improves LED chip performance and longevity.
Common LED chip package types include:
SMD packages allow easier PCB assembly while COB arrays simplify optics design. Consider package height restrictions and soldering processes when selecting.
Choosing optimal LED chips by carefully evaluating key parameters like power rating, luminosity, efficiency, color characteristics, lifetime and thermal management enables creating energy-efficient, long lasting and good quality lighting products. Leverage the latest mid-power and high-power LED chips to realize substantial energy savings and simplified lighting design. With technology advancements delivering ever more performant LED chips, lighting product developers can take advantage by selecting the most appropriate chips to meet their precise application needs.
Mid-power LEDs (1-3W) strike a balance between light output and easier thermal management. High-power LEDs (5-10W) produce higher brightness but require substantial heat sinking.
Proper PCB thermal management through large copper planes, thermal vias, airflow and heat sinks is crucial to ensure LED chips operate at optimal temperature for maximum light output and reliability.
Operating LED chips at high junction temperatures accelerates luminous decay, color shift and failures over time. Quality encapsulation also protects against moisture ingress and corrosion.
Yes, white LEDs can gradually shift to a bluer tone over tens of thousands of hours of use. Higher quality LED chips exhibit better color consistency throughout their lifetime.
Photon or wall-plug efficiency defines the LED chip&#;s inherent ability to convert electrons to photons. Maximizing this improves luminous efficacy (lumens per watt). Chip design, materials and packaging maximize photon efficiency.
How to Choose the Light PCB Assembly or PCB LED Lighting Assembly Manufacture in China?
With the development of the Lighting/LED industry, there are more and more assembly manufacturers for you to choose from&#; As a Professional PCB and PCBA Manufacture, FX PCB gives you the suggestions below on finding the proper Light PCB Assembly manufacturer to get the LED PCB assembly cost and good quality.
1, Check the LED PCB Assembly Machine
You need to consider the performance of the PCB assembly equipment, for example, the placement speed and the placement accuracy. As if the speed is not fast enough, it won&#;t be a problem for you to produce the low volume /Small batch PCB assembly for your LED board, but you will have a problem with the high volume/ mass production light PCB assembly. The accuracy of the placement equipment is the key factor you need to take into consideration, as you don&#;t want to have the poor position of your LEDs on your board, which will bring you quality problems. So check the PCB Assembly machine of your manufacturer first before placing the order.
2, Check the Manufacturers of Your LEDs
Find reliable LEDs manufacturers for your products, there are many brands for you to choose from, for example, Lumiled, Osram, Cree, Samsung, Luxeon, Everlight (Taiwan Brand), and some other China brands. Different products can choose different LEDs, you just need to find the right one based on the function, usage, and requirements.
3, Check the PCB Assembly Process
The light PCB assembly manufacturer should have a detailed assembly process, as it can improve manufacturing efficiency and make the work process more standardized.
As a contract light PCB assembly manufacturer, FX PCB strictly follows ISO and tries to be the best PCB assembly company for LED in Shenzhen China. Contact us and get the PCB assembly cost now.
What is a light PCB Assembly?
Light PCB assembly is the process of assembling and soldering PCB components onto a printed circuit board (PCB). The major purpose of this process is to build a functional electronic device. It includes inserting and soldering components such as:
Light PCB assembly includes testing the assembled PCB to ensure the functioning of the device comprehensively. Light PCB assembly is often used in the production of:
How to Choose a PCB LED Lighting PCB Board Assembly Material?
Factors Determining Type of PCB Material
Fire Retardant
The material should be fireproof. If a fire breaks out, this material should be able to slow or stop its spread.
This characteristic is due to chemical reactions. Such reactions reduce the flammability of the fuels.
They also efficiently extend the fuel&#;s combustion time. This keeps the light board from catching fire.
Dielectric Constant
Another factor to consider is the substance&#;s ability to store electrical energy.
The dielectric constant should be able to tell you the magnitude of the electrical force as well. This is an important factor to think about. Generally, all light boards are intended for use in electrical appliances. Check the material&#;s ability to store electrical energy.
Loss Factor
Dielectric loss is another effect of the substrate material used. The dissipation factor is used to compare the loss performance of various materials.
If the dissipation factor is low, the laminate has a dielectric loss.
Check the dielectric loss of the laminate material utilized in the substrate.
Tensile Stability
This is the ability of a substance to break while under tension. In layman&#;s terms, it refers to the highest sustainable load that the material can withstand.
This means that no fractures will be reported even in cases of stretching.
Make sure your light PCB material has the necessary tensile strength.
Glass Transition Temperature (Tg)
This is an extremely significant feature to think about when choosing polymers for end use.
Plastics&#; physical qualities are converted into crystalline or even glassy states at glass transition temperatures.
The same materials turn rubbery when heated above the glass transition point.
Make sure you use a material with a high Tg in your light PCB design. This will help to ensure that the board functions well even under adverse conditions (temperatures).
Z-axis Expansion Coefficient
The size of the object changes as a result of exposure to various temperatures. Thermal expansion is another way to describe it.
Calculating the thermal expansion coefficient requires constant pressure. There have been several techniques developed recently for monitoring thermal expansion. Volumetric, area, and even linear are some of them.
What Are Light PCB Board MaterialS?
CEM 1 and CEM 3
CEM-1 Three components are typically used to create composite materials. These comprise paper core and woven glass fabric linked together. After that, epoxy resin is added to these two.
The printed circuit board industry frequently uses this material. It often has great electrical characteristics and is simple to punch.
In comparison to grades made from paper, CEM has a higher flexural strength. This results in exceptional mechanical and even electrical qualities.
These factors have helped it become more well-known in the Asian market. Additionally, it is popular due to its benefit of being a flame retardant.
They are typically employed in the production of both multilayered and double-sided light PCBs.
As a new PCB substrate material, CEM-3 depends on the technology of FR4. This explains why it has recently been employed to replace FR-4.
If you want to learn more, please visit our website Shenzhen Thriver Digital Tech Co., Ltd..
FR4
Most manufacturers prefer FR-4 because it performs well in all the desired areas of a good substrate.
Aluminum
This is talking about PCBs with an aluminum metal core. The PCB&#;s primary component in this PCB is aluminum. This contrasts with the standard FR4, CEM-1, or CEM-3.
Aluminum metal core PCB provides superior heat dissipation characteristics compared to other materials.
They can transfer heat away from the components in this way. Typically, a thermally conductive dielectric layer is used to achieve this.
Aluminum is the most popular material for Light PCBs because of its heat conductivity.
Copper Alloy
These are metallic alloys, primarily made of copper. They have a very strong resistance to corrosion as a result.
Moreover, conventional kinds are used. These include bronze, which requires a large amount of tin.
The third option is brass, which has a large amount of zinc.
Light PCB Manufacturing Process
The light PCB manufacturing process starts with design and verification and continues through circuit board manufacturing. Several phases demand computer direction and machine-driven equipment in order to maintain quality and prevent short circuits.
Step 1: Design and Output
Design is the first stage in the manufacture of PCBs. This will serve as the schematic blueprint that directs how the board is made. It is a laid-out plan that complies with all of the demands of the intended board.
Typically, the software is used to implement this design. The most widely used PCB design software is Extended Gerber, often known as IX274X. Altium Designer, KiCad, Eagle, OrCAD, and Pads are examples of commonly used PCB-design software.
Step Two: Design Review
This is a crucial stage in the production of printed circuit boards. It involves inspecting the design for potential flaws or defects, including breaches of the manufacturing standards and PCB layout rules, as well as ensuring that it adheres to the necessary specifications.
These are some crucial questions for this review:
Step Three: Printing the LED PCB Assembly Design
The PCB design is printed after all the checks have been carried out. The PCB design is printed using a unique printer known as a plotter printer. The printer creates a film that displays the board&#;s layers and finer details.
This film is exactly like the board itself in a photo negative. On the inside layer of the board, two ink colors are applied during printing: Clear ink is used to highlight non-conductive components like the fiberglass foundation.
Step Four: Light PCB Fabrication Process
Aluminum is the most often used material for light PCBs, as we already mentioned. This aluminum PCB&#;s fabrication procedure often differs slightly from that of conventional PCBs.
Cut Lamination
This is the method of cutting the big incoming sheets of material to the necessary smaller sizes for manufacture. As the title suggests, the procedure entails choosing and cutting the sheets.
The first piece&#;s size during cut lamination must be carefully monitored to ensure accuracy. Additionally, you must pay great attention to the scrapping of aluminum and copper and be cautious of blisters.
Drilling
Drill holes in the through-hole component holes once the lamination has been cut.
Make sure the holes you drill match the design in terms of size and number. Additionally, watch out for drilling that can scratch the sheet.
The burr on the metal surface should be checked as a further precaution. Additionally, make sure there are no hole deviations.
Always check the drill tool to make sure it is operating flawlessly before replacing it to get the best results.
Dry/Wet Film Imaging
In this case, you&#;ll grind the plate before exposing the film and developing it. The purpose of doing this is to draw attention to the components on the page that the circuit will require.
After development, make sure to check for open circuits. Additionally, keep an eye out for any changes in how the development is aligned. Potentially, this could stop the formation of dry film.
Additionally, keep an eye out for faulty circuits. Particularly if there is a surface scratch, they can happen.
When exposed, avoid air residue. If this happens, the exposure may be poor. Allow fifteen minutes to pass once the exposure is over before developing.
Acid/Alkaline Etching
The goal is to keep the necessary amount of electricity in while removing any excess. As a result, you will etch, strip, dry, and then check the board.
You must always pay attention to the circuit width and space when acid/alkaline etching. Do not let even light scratching or oxidation of the copper surface occur.
Solder mask and Silk Screening
In order to protect the board&#;s non-solderable areas and avoid short circuits, a solder mask is applied.
Make sure to properly inspect the board and eliminate any extraneous materials throughout this process. Additionally, check that the stencil you&#;re using is clean.
Once the silk screening is finished, procure at least 30 minutes to make sure the circuit is bubble-free. Chill the procuring plate to prevent it from sticking to the film.
Therefore, the entire silkscreening and solder masking process can be summarized as follows:
V-Cut, Rout Out
Basically, the purpose of this process is to disassemble the constituent circuit units to make packaging and shipment simpler. Routing also aids in removing extra board components.
Make sure the &#;V &#;&#;s&#; depth is appropriate while performing the V-cut. Additionally, look for flaws toward the edges. Be on the lookout for detours as well.
The routing tool needs to be checked frequently, exactly as we previously advised with regard to the drill tool. If necessary, repair or replace them to make sure they are in great operating order.
Make sure not to scrape the board when you remove the burr.
Electronic Test, OSP
This method is helpful in determining whether the circuit is functioning properly. Additionally, you may verify that the circuit can survive the required voltage environment. Additionally, it is to make sure that the circuit is flawlessly soldered.
Make sure to correctly discern between products with flaws and those that are good. Make sure the circuit is completely unharmed.
Packaging and Shipping
Here, you may confirm that the board has good quality by doing the final overall quality check. It entails selecting a few samples from the finished circuit boards and evaluating their caliber.
Separate outboards whose look does not demonstrate perfection via visual assessment.
The boards that pass this inspection are then packed and sent to the appropriate purchasers. Be careful when packaging to avoid mixing good and faulty boards or providing the wrong boards to the consumer.
Make sure the boards are stored in accordance with the recommended methods for storing aluminum substrates in the industry.
Step 3: Light Circuit Board Assembly Process
An extra level of care must be taken during light PCB assembly, just as it is throughout the fabrication process, to ensure flawless results. Boards with poor solder joints and alignment will be the outcome of reckless work.
This is especially true given how delicate the silver base material is. During the assembling process, different light PCBs will require different considerations.
The steps involved in light PCB assembly are as follows:
Preparation of the Materials
Check each component, PCB stencil, solder paste, and bare board in great detail.
Check the tools as well to make sure they are all in excellent shape. Keep in mind that even the smallest error in PCB construction can result in the complete failure of the finished product. Make sure, among other things, that the soldering iron, wire remover, pliers, and tin are ideal and prepared.
Additionally, you need to place your BOM list and Gerber file on the desk. During the assembly process, you will keep referring to them.
Utilize the AOI tool to inspect the soldering for any issues after soldering.
Connect the leads of the through-hole components to the boards through holes. Make sure each piece is inserted in the proper location.
Put the wave soldering machine where you placed your light PCB now. For stronger joints, the machine will use spray welding flux, preheating, soldering, and ultimately cooling.
Cleaning the board is the first step after completing the component assembly. After that, run the finished board through one more quality check to make sure there are no defects.
The final tests have been completed, and all PCBs are now prepared for packaging and shipping.
Conclusion
The manufacturing process for printed circuit boards (PCBs) is lengthy and complex and each step must be carefully carried out to guarantee the best possible performance of the finished board. Although the processes are repeated for a multilayered board, the fabrication process for single, double, and multilayered PCBs is essentially the same.
Shenzhen PCB assembly manufacturers like SFX PCB developed methods that enable the assembling of all LEDs. Shenzhen PCB assembly manufacturer is the ideal place for your Light PCB assembly needs. We can assist you in assembling everything from industrial high-power LEDs to commercial flood LEDs.
Want more information on Led Lighting PCB Assembly? Feel free to contact us.