LED PCB: All You Need to Know

Printed circuit boards, primarily known as PCBs, are dominantly present in our technological society. You will undoubtedly find a printed circuit board in cars, computers, industrial machines, and many other electronic products. However, manufacturers tailor numerous printed circuit boards to suit their various purposes. This article looks at one such printed circuit board called LED PCB. Read on to learn more.

What is an LED PCB?

Firstly, LED is an acronym meaning Light-emitting diodes.

LEDs on a PCB board

Now, these LEDs are mounted onto a LED printed circuit board, and it is through the LED PCB that the diodes are light.

Since the working of LEDs tends to produce a large amount of heat and can't be quickly cooled traditionally, they require a means to release the excess heat.

This excessive heat dissipating method could be a heat sink or a particular material like aluminum.

Hence manufacturers prefer using aluminum (metal core PCBs) to make LED PCBs mainly because they constitute a thin thermal conductive dielectric material.

The dielectric material enables the aluminum PCB to dissipate heat quicker than the typical rigid PCB board.

LED devices mostly employ a surface-mounted design in their packaging. Nevertheless, since the SMD only supports a single LED, we need more light. The circuit board links numerous LED components to produce adequate light.

LEDs on a stripe

The LED Lighting Industry

Like all other industries, the LED lighting industry has evolved continuously to become a popular lighting solution.

However, the industry also has its fair share of benefits and challenges:

Benefits of LED lighting

• Longer life cycle – on average, an LED light can provide you with up to 25000 hours of use. Their lifespan is 23 times longer than the standard bulb, thereby saving you money and the hassle of installing a new bulb.

LED bulbs

• Highly efficient – a standard incandescent light bulb uses more than 90% of energy in heat production. Whereas an LED only produces 20% heat energy; as a result, they spend more energy lighting your home than heating.
• Compact- due to their small size, manufacturers can use LEDs in applications of various sizes like traffic lights, sockets, and more.
• Mercury-free- LEDs do not have mercury, making them environmentally friendly.
• Reduced power consumption- averagely, when you switch from an incandescent light bulb to an LED, you cut power consumption by 90%

The challenges of LED lighting

• High-temperature production- LEDs consume up to 20% of electricity in heat production, which dramatically affects the LED lifespan.
• Light color- the color an LED produces depends on the working temperature, thereby limiting LED light usage.

Components of LED PCB Board

The most basic LED PCB consists of four layers, the primary one being the substrate. Since LEDs emit a lot of heat, the substrate is usually a metal (aluminum) to channel the heat out fast. This metal layer must have an insulation layer to separate its conductive nature from the copper traces, which form the second layer.

LED PCBs with different bulb configurations

The third component is the solder mask, which forms a protective layer above the traces to prevent short-circuiting, oxidation, and corrosion. Above it is the silkscreen, which contains important markings and labels about the assembled components and where to mount them.

We can’t fail to mention the primary electronic components in this board as the fifth element in the stack. LEDs are semiconductor chips that emit red, blue, or green light when current passes through them from the anode to the cathode.

Types of LED Printed Circuit Boards

Different LED Circuit Boards types work well on various applications.

LEDs on a PCB

They include;

Hybrid LED PCB

A hybrid circuit board constitutes a base metal (mostly aluminum) and a non-thermal material (FR4). Hybrid LED PCBs are rigid and inexpensive.

Aluminum circuit board

Single-layer LED PCB

A single-layer LED PCB Board contains only one layer of the copper conductive substrate.

Manufacturers use copper to make the metal layer because copper is a good conductor.

Single-layer LED PCBs are easy to design, affordable and versatile.

Flexible LED Circuit Boards

As the name suggests, this type of PCB Board is highly malleable.

Since you can twist a flexible LED PCB in various directions and even fold it, they are more preferred than a rigid PCB.

Multilayer LED PCB

A multilayer LED PCB consists of several copper conductive layers between insulators. Copper-plated holes interlink these layers.

Also, the materials stay together with the aid of a powerful adhesive.

A simple multilayer LED PCB contains only four layers; however, some used in complicated tasks can have 50 layers.

Rigid LED PCB

A rigid LED PCB constitutes solid materials that also function as substrates.

Rigid LED PCBs are commonly used in applications that require the LED PCB to constantly stay in shapes, such as computers and remote controls.

Also, rigid PCBs come in various forms, for example, single, double, and multilayer LED PCBs.

Aluminum PCBs for the LED Lights

Basics of Aluminum PCB

Most LED metal-core PCBs have an aluminum alloy base that consists of magnesium, silumin, and, of course, aluminum. The percentages of these elements are optimized to maximize thermal conductivity.

Since aluminum is electrically conductive, there must be a thermally conductive layer between the base and the copper traces, and the most suitable material is a ceramic polymer. This material provides viscoelastic and thermal resistance properties that protect the rest of the PCB from thermal and mechanical damage by efficiently transferring the heat to the aluminum for dissipation.

The thermal conductivity for this insulation material should range from 1-3 W/mk and its thickness should be 3 mils, while the aluminum thickness should be around 57 mils to provide structural strength. Lastly, the circuit or copper foil layer should be 1.4 mils thick.

Benefits of Aluminum PCBs for LEDs

Aluminum is more affordable than ceramic and other metals, so these PCBs are generally cost-effective. The material also serves as an efficient heat sink for the circuit.

The metal is also easy to recycle, non-toxic, stronger than fiberglass (FR4) and ceramic, and lightweight. Ceramic only beats aluminum in thermal conductivity because it does not need an insulation layer. However, the ceramic polymer dielectric enhances the performance of these aluminum PCBs for LEDs.

Aluminum LED PCB Boards Design Advancements

Adjusting and testing different metal-core alloy element percentages has made it possible to include a higher LED density on the board because the base has become more efficient at dissipating heat. This faster dissipation also means the LEDs can have longer operating times because excessive heat significantly reduces their lifespan.

How To Make an LED PCB Board

Determine the Requirements

Begin the process by determining the board’s requirements, including weight, dimensions, maximum power rating, IP rating, number of LEDs, etc.

The type of LEDs is also important to consider in this phase. Through-hole LEDs take up more space but are easy to solder. Surface-mount LEDs take up little space but can be difficult to mount manually.

Through-hole LEDs on a PCB

COB LEDs are brighter than the other LEDs but are mounted directly on the substrate, which complicates the fabrication process, implying a higher production cost.

Design the Circuit Board

With all the requirements in place, use your preferred design software to create the circuit’s schematic with the components connected by electrical lines.

Pick the Most Suitable Materials

The most typical PCB material is FR4 (fiberglass), but this might not be the best for LED boards. Consider substrates like copper and aluminum alloys or even ceramic. Each material has different thermal, electrical, dielectric, and weight properties, so consider these to pick the most suitable base layer.

Create the Board Layout

Translate the schematic diagram into a physical representation of the board, with all the components in their specific locations and the traces properly routed. When creating this layout, consider things like EMI and crosstalk prevention.

A PCB layout

Manufacture the PCB

For simple LED board designs, you can try building the board as a DIY project if you have the technical know-how. But for complex circuits, we recommend looking for a professional fab house to build the board either as a low-volume or high-volume batch.

Assemble the Components

The next process is to assemble the LEDs and other components on the board. Like with manufacturing, you can do this assembly as a DIY project if handling a small batch of PCBs with simple circuits. But professional assembly is the best option for large batches of complex board circuits.

Test the Complete Board

Assembly goes hand-in-hand with testing before use, and the most common testing steps include electrical and shock/vibration testing, as well as visual checks, usually using automated optical inspection.

Factors to Consider When Designing a LED PCB

They include;

• Material
• Heat management
• Trace routing
• finish

Let us scrutinize these factors closely;

Material

The materials you use need to work together to serve three essential functions; conductor insulation, heat dissipation, and effective LED component connection.

Most LED circuit boards use aluminum as the base layer, and it is on this layer that the other PCB electronic components sit.

Circuit board with LEDs and other electronic components

After the base layer, we have a thermal insulation layer made of polymer that guards the board against mechanical and thermal destruction.

As the circuit functions, it produces heat, which the thermal insulation layer absorbs and subsequently transfers to the base layer. The base layer then dissipates the heat.

Some PCBs have a ceramic base and thermal heat sink for increased heat transfer capabilities.

Aluminum heat sinks

Next is the circuit layer constituting copper circuits arranged according to the LED PCB Board design.

Manufacturers call this structure design an insulated metal substrate (IMS).

Thermal Management

LED PCBs produce a large volume of heat; hence, thermal management is critical to increasing your device's lifespan.

A printed circuit board

Therefore, your design needs to include heat sinks and aluminum cores (Aluminum PCB) for effective heat dissipation.

Above all, consider the Light-emitting diode placement and component positioning as they affect heat release and heat circulation.

Trace routing

Accurate trace routing reduces overheating, short-circuiting, and circuit cross-talk. Also, consider the mounting hole spaces for effective functioning.

Finish

The circuit board's finish safeguards the circuit layer while ensuring adequate component soldering locations.

You can choose a finish depending on your project needs and budget.

Types of LED Used in PCBs

Surface mount LED alias Integral point LED

The surface mount LED has a production process similar to surface mount technology. Both systems' designs entail affixing the LED at the lower circuit base.

Block LED

Also known as Single point LED. The block LED has numerous purposes because of its textured surface and magnificent light diffusion.

The Advantages of LED PCB

• Long lifespan
• Highly efficient
• Water and dust resistant
• Wide variety of applications
• Mercury-free
• Lowers costs of operation
• Reduced power consumption
• Easy to incorporate
• Maximum design flexibility

The Application of LED PCB

• Telecommunication
• Consumer lights
• Medical Equipment
• Consumer electronics
• Street lighting

• Automotive industry
• High growth plant lighting

Problems often Encountered in LED PCB Assembly.

LED PCB Board assembly may seem simple, but it is far from it, as there are problems you will encounter, such as material selection and current control.

However, you can quickly get over these hurdles.

OurPCB: Leader in LED PCB Circuit Design, Manufacturing, and Assembly

If you’re looking to get your LED PCBs designed, manufactured, and assembled professionally, OurPCB has the equipment and expertise to help you realize your project. We will help you create a PCB stack that dissipates the heat quickly from the LEDs to manage the thermal issue.

Additionally, we are ISO 9001:2015 certified and provide Lead-free, RoHS-certified assembly, which means we can deliver electronic products that you can sell to most parts of the world.

Summary

Current PCBs are smaller and have more layers than their predecessors, thus enabling them to work longer while producing less heat. Working with a company that is a leader in LED PCB manufacturing will allow you to exploit all the advantages of LED PCB.

OurPCB has handled led lighting from the infancy stages of this technology. Our experienced and caring support team is eager to hear your LED PCB requirements; contact us for high-quality PCBs at competitive prices.