With technological improvements, flexible PCB for LED strips is becoming more popular.
We can attribute this to them offering a more practical and cost-effective approach.
Moreover, they eliminate unnecessary wiring we see in rigid circuit boards.
But if we ask, what are the characteristics of flexible PCB LED strips, and how can you assemble LEDs on FPC?
Very few have answers to such a critical question.
Count yourself lucky as we have prepared this article to help you understand everything related to flexible PCB for LED strips. Let’s get rolling.
Table of Contents
- Flexible PCB
- Flexible PCB for LED Strips
- Characteristics of Flexible PCB LED Strips
- How To Assemble LEDs on FPC
- Understanding COB LED Strip Light
- How To Choose LED Strip Lights
Before we look at flexible PCBs for LED strips, we first need to understand the functionality of flexible PCBs.
It’s a circuit with materials that can fold and bend without breaking.
Therefore, the circuit board has a polyimide material with metal trace layers glued to it.
Polyimide materials usually have a thickness range between 0.0005 to 0.01 inches.
Moreover, the metal traces have a thickness of at least 0.0001 inches.
And we have adhesions like epoxy to attach the different layers.
However, some designers employ the vapor deposition method as an alternative to adhesions.
Furthermore, we add a protective layer to prevent cases of copper oxidation.
Most designers prefer flexible to rigid PCBs because they are lightweight and use less space.
Flexible PCB for LED Strips
(Installing an LED strip lighting)
Flexible PCB LED strips are light-emitting diode strips mounted on a bendable or flexible circuit board.
Sometimes, people call them chip-on-board (COB) light-emitting diode flexible circuit board assemblies.
And the strips find everyday use in lighting applications, including wearable products, homes, and shops.
There are several types of flexible PCB for LED strips:
Single Layer Flexible PCB
This is the lightest flexible PCB with about 1oz copper layer on a substrate. In most cases, it has the following materials:
- A polyimide substrate
- Copper conductors
- A protective finish
- An adhesive material
Double Layer Flexible Circuit
Unlike the single-layer option, this option has two conductive layers on either side of the substrate.
Therefore. Expect it to be thicker and heavier than the single-layer circuit board. As a result, it conducts more current and dissipates heat faster.
A double-layer circuit board has the following layers:
- A top and bottom conductive layer
- A top and bottom overlay or coverlay
- A core substrate material
- Top silkscreen layer
- An adhesive layer for strip mounting
- An adhesive layer protective liner
Characteristics of Flexible PCB LED Strips
(Flexible LED strip blue light roll)
Excellent flexibility: This feature lets you use flexible PCB LED strips in complex conditions.
It becomes easier to bend the circuit to fit in tight spaces. Therefore, you can easily design compact systems and devices.
Small size and lightweight: Generally, we know that flexible circuit boards are thinner and lighter than rigid circuit boards.
Therefore, the same applies to flexible PCB LED strips since you fit them on flexible PCBs.
Poor cooling: A common problem in flexible PCB LED strips is poor cooling. However, this is rare in rigid circuit boards. To some extent, poor cooling might affect the LED strip performance.
But with excellent design, you’ll rarely experience the effects.
How To Assemble LEDs on FPC
Light-emitting diodes are semiconductors with P-N junction parts that lets current flow through in a single direction. At the same time, they convert electrical power to light energy.
Therefore, to assemble the light-emitting diodes on flex circuit boards, consider any of the following methods:
Wiring bonding: You employ gold wires to connect the flex PCB to the LED chip pin
Tape Automated Bonding: Unlike the wiring bonding that uses gold wire, this option uses copper foils to connect flex PCB to LED chip pins.
Flip-chip: With this option, you connect the flex PCB pad and LED chip pin’s bump without using wires.
Understanding COB LED Strip Light
Chip on board (COB) is a method that involves packaging chips on a circuit board directly. In other words, it is like an integrated package technology for light-emitting diodes.
What’s COB LED Strip?
COB LED strips involve encapsulating a strip of chips on a flex circuit board. These chips are often flip-chips fixed on the circuit board linearly. Additionally, you drop a mixture of encapsulation glue and phosphor on the chip surface.
As a result, lights from the chip undergo reflection and refractions and interacts with the phosphor. On the other hand, the glue will evenly emit various colors and color temperatures.
Alternatively, we refer to COB LED strip lights as dotless LED strips or continuous LED strip lights.
Benefits and Features of COB LED Strip
No Ligit spot, even, and uniform without aluminum profile: One main downside of the traditional LED strips is the availability of light spots.
Therefore, light becomes unattractive and less soft.
Fortunately, COB LED strips eliminate light spots making them ideal where
- You’d like to have an excellent neon effect.
- You have reflective surfaces like glass or granite around.
- You can’t hide the LED strip from the view.
- You’re illuminating a surface within 2 feet of the light bar.
More flexibility: COB LED strips use small-sized diodes and have a uniform weight distribution making them lighter and more flexible than other flex strips.
As a result, you can use them in tight spaces and applications that require them to turn corners.
Wide emitting angle: These strips have an emitting angle of 180 degrees compared to the 120 degrees for the traditional SMD strips.
More stability and fewer problems: You attach COB strips directly to the flexible circuit board without gold wires.
However, traditional SMD strips connect to the circuit board with gold wires, thus prone to damage.
Long lifespan: Since you attach COB strips directly to your circuit board, any heat they generate is quickly transferred to the board.
Therefore, they dissipate heat faster and consequently boast a smaller light decay and longer lifespan.
Applications of COB LED Strips
(LED strips on evening life country house kitchen)
COB LED strips are highly versatile and find applications in different industries.
- Shopping mall lighting
- KTV bar lighting
- Hotel renovation lighting
- Architectural lighting
- Parking lighting
- Furniture and wine cabinet lighting
How To Choose LED Strip Lights
(Master glues LED strip into a niche)
While selecting the best flexible PCB LED strips, understand how much light they give out to avoid embarrassment and disappointment.
In this section, we help you choose the right LED strip lights.
Location of Use
After finishing with ceiling development, place your LED tape away from the wall to eliminate light dotting.
The right distance is 40 mm from the wall and 90 mm away from the ceiling.
LEDs per Length
The number of LEDs per length of the strips determines the quality and brightness of the flexible PCB strip.
Therefore, select a strip with many LEDs per meter for the best light quality and maximum brightness.
LED Strip Brightness
Nowadays, modern LED strips offer more light than traditional options.
However, you’ll have situations like accent lighting requiring glowing light.
Therefore, check the lumens amount listed on the strip and only buy one with a higher number.
Color and Color Temperature
LED strip lights are available in single color or different RGB colors.
Therefore, expect the color-changing strips to display any color combinations, in most cases being red-green-blue.
Moreover, color temperature represents the difference between white colors emanating from an LED strip.
Generally, it shows how warm or cool the light is.
LED Strip Powering and Wattage
How much power does the system require? Answering this question will help you get the perfect power supply.
LED Strip Wiring
Understanding LED strip wiring will save you from unexpected failure.
Fortunately, most LED strips have connectors to make the connection process straightforward.
Therefore, only choose an LED strip that you can wire comfortably.
How thick is a flex PCB for LED Strip?
Flex circuit boards have an average thickness of 0.2mm to 0.4mm.
This means 0.2mm and 0.4mm thickness for single-layer and double-layer circuit boards, respectively.
Does LED Strip consume a lot of power?
Not at all! LED strips use less power to produce the same light energy as fluorescent lamps.
Case example, they use about 18% and 80% less power than compact fluorescent lamps and conventional incandescent lighting, respectively.
Therefore, if you intend to save on energy costs but get an excellent light output, count on LED strips.
Can you connect multiple LED strip lights?
Yes, you can connect multiple LED strip lights. However, they should have the same voltage.
Otherwise, the LED strip light won’t work and, in the worst cases, get damaged.
Therefore, the positive connectors should be aligned when plugging the strips in.
That is all we can say about flexible PCB for LED strips.
Flexible PCB LED strips are light-emitting diodes on a flexible, bendable circuit board.
These strips have a longer lifespan, high efficiency, and are lightweight. However, they might have poor cooling abilities.
Moreover, you can use them in multiple applications, including wearables, architectural, and hotel lighting.