You’re likely here because you want to know what materials make up a flexible LED PCB.
If such is the case, you have landed in the right place.
We all appreciate that light-emitting diodes (LED) are increasingly becoming popular and finding applications in different fields.
Surprisingly, LEDs reduce energy consumption by almost 80% and can last up to 25 times longer than traditional light bulbs.
Moreover, they’re environmentally friendly and smaller in size.
However, few understand that LEDs are designed thanks to printed circuit board technology.
We also have flexible LED PCBs that allow you to fold and twist them without breaking them. But what materials make up a flexible PCB?
This article tells you everything you need to know about flexible PCB materials.
Table of Contents
- What Is An FPCB?
- What Are LED PCBs?
- Role of FPCBs in LED Strips
- FPCB Structure and Materials
- Copper Weight
- Heat Dissipation
- LED PCB Development
- FPCB Assembly
What Is An FPCB?
(A flexible PCB)
Most of us have interacted with traditional rigid circuits and understand their features and applications.
However, you might not know that flexible circuit boards borrow a lot from rigid ones.
They have the same functionality, except that flexible PCBs have materials that allow them to fold and bend.
The main materials on flexible PCB are conductive copper and polyimide substrate. Surprisingly, they also have stiffeners, coverlays, and adhesives to support the board.
If you’re working on developing a compact electronic device or want a PCB that fits in tight spaces, think no further than a flexible circuit board.
What Are LED PCBs?
(A photo of FPCB LED)
LED PCBs are simply light-emitting diodes on a circuit board. In most cases, we use LED PCBs in lighting applications. And what’s more, you can control them using switches and chips.
Some of the main applications of LED PCBs include the following:
- Medical devices and room lighting
- Tunnel and street lighting
- Automotive lighting
- Flashlights, work lamps, and torches
- Signal lighting
- Display panels and indicators employed in composting and telecoms devices
LED PCBs have distinct characteristics and qualities that make them perfect for the above applications. They include the following:
- They’re lightweight and low profile
- LED components are efficient to run and cheap to buy
- Longevity and reliability
- They’re resistant to moisture ingress and dirt effects
- LEDs are highly versatile
Role of FPCBs in LED Strips
FPCB offers a platform where you can mount LED chips using surface mount technology (SMT).
Therefore, the PCB offers structural and physical support to your light-emitting diodes.
Additionally, it dissipates heat generated by the LED during operation. Therefore, LEDs are more effective on FPCBs.
FPCB Structure and Materials
We prefer using flexible PCBs in LED strips thanks to their malleability. In most cases, we use 5-meter reels.
Polyimide substrates are the most common materials thanks to their heat resistance and durability.
Generally, you can use a single or double-layer circuit board for your LED strips.
Single Layer PCB
This circuit board has single conductive copper and polyimide substrate layers. Generally, this circuit board is thinner and has a silkscreen and solder mask for protection.
Surprisingly, you will find no circuits on the backside. And what’s more, this option is cheaper than the double-layer circuit board.
Double Layer PCB
A double circuit board is a PCB with a polyimide substrate between two copper layers.
Therefore, this enables designers to place solder mask layers on each copper layer.
Surprisingly, this makes them heavier and thicker than single-layer circuits.
Moreover, the high surface area enables double-layer PCBs to have a high heat dissipation. Also, they can handle high currents, thus making them highly durable.
We measure the circuit board thickness in copper ounces (oz).
This is the amount of copper you need to attain a thickness of at least one sq.
Therefore, you must consider the copper thickness while shopping for LED strips. We recommend thicker copper of about 2 to 3 oz for high-powered LED strips.
Using LED strips with thicker copper presents the following benefits:
- They have a better overall performance
- They’ll dissipate heat faster
- More power will flow through the LED strips circuit
- You won’t experience any voltage drops
- A thicker strip has a lower electrical resistance
Since circuit boards allow current to pass through, they will generate heat. Surprisingly, flexible circuit boards have poor heat dissipation performance.
We can attribute this to the FPCB benign thin.
Fortunately, you can implement the following to eliminate the heat dissipation challenge:
- First, employ the LED channel as a heat sink. Also, the LED channel will improve the light effect and protect the light strip.
- Second, use wider or thicker circuit boards. A thicker or wider circuit board will dissipate heat faster.
Finally, use MCPCB or FR-4 in place of FPCB. However, these circuit boards have better thermal performance but are not flexible.
LED PCB Development
(A flexible LED strip)
When you want to create LED lighting products or develop a system that employs LED strips, the following steps will help you.
FPCB LED Strip Design
The first step is to develop a design per your application requirements. Fortunately, many software can help you develop a reliable design. And if the design isn’t your thing, you can approach a design engineer or professional to help you.
Flexible PCB Manufacturing
This might be the most difficult stage involving prototyping and production. This is where you develop the FPCB and attach your LEDs. Some options you might consider manufacturing include HDI flexible PCBs, double-sided flexible PCBs, single-sided PCBs, or thick-copper flexible PCBs.
Sourcing Electronic Components
This is the time to source LED chips and any other components on your bill of materials. However, ensure you don’t compromise quality for the price.
We have two main methods of attaching components to your PCB. Check them out below:
- Surface Mount Assembly (SMT): With this method, you mount your components directly on the FPCB surface. This process is highly automated, thus allowing for excellent flexibility and high connection densities. But first, place solder paste on the FPCB with the pick-and-place machine. Next, heat the FPCB to form solder joints and inspect it to guarantee proper functioning. We recommend this method for applications that need complex circuitry in compact electronics.
- Thru-hole Assembly: With this approach, you drill holes in your FPCB and run components we call leads through them. Next, you apply solder to hold the components in place. Also, you carry out an inspection to ensure circuit effectiveness and accuracy. Surprisingly, this method offers more durable and stronger connections.
Finally, you should conduct IC programming, thermal aging, functional testing, and end-product assembly. If everything is fine, you can use your flexible LED PCB.
Is FPCB important in LED strips?
Yes! Over the years, manufacturers have incorporated LED strips in their designs.
Therefore, FPCBs offer LED strips as the structural base where the connection happens.
Moreover, they help to dissipate the heat generated by LEDs faster.
What are FPCB Limitations?
FPCBs aren’t perfect, and you might encounter challenges while using them. First, these boards are limited in size, and they damage easily.
Also, they have a complex manufacturing process that contributes to their high prices. And when they get damaged, repairing or changing them is difficult.
What’s the LED strip substrate’s role?
This is simply a structural and physical support system where you mount your LED components. It’s also where you connect the power supply to the LED strips.
Finally, if your LED strips generate excess heat, the substrate must dissipate it.
Flexible LED PCBs involve mounting light-emitting diodes on a circuit board to form a circuit that you can control through switches or chips.
Conductive copper and a polyimide substrate are the main materials for designing circuit boards. Also, we have stiffeners, coverlays, and adhesives to offer strength.
Surprisingly, flex circuit boards are lightweight and resistant to harsh conditions.