Guide to Purchasing COB LED Strips: Must-Know Facts

COB (Chip-on-Board) LED strips have quickly become a popular choice for modern lighting solutions, thanks to their seamless light output, high efficiency, and compact design. Whether you’re upgrading your home lighting, working on a commercial project, or diving into DIY setups, understanding what to look for when purchasing COB LED strips is essential.

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This guide covers the key facts you need to know—from performance benefits to technical specifications—so you can make a confident and informed buying decision.

What is COB?

In the realm of LED technology, COB refers to Chip on Board. This means the LED chip is directly integrated onto the circuit board, also known as PCB. Flexible strip lights with “Chip on Board” LEDs are sometimes called flip-chips.

In essence, flip-chip LEDs represent a minimalistic approach to LED design. To illustrate, consider a typical SMD (Surface Mount Device) LED, which features a lamp bead holder that packages the LED chip and then applies a phosphor coating layer. The ‘flip-chip’ design of the COB LED strip strips away all but the LED chip, yellow phosphor cover layer, and connecting pads.

So, what exactly is a COB LED strip light?

A COB LED strip light or tape light involves LED chips directly mounted onto the FPCB (Flexible Printed Circuit Board). It results in a seamless, dot less LED strip light, which is why COB LED strip light is also known as continuous or dot less.

How do COB and SMD LED strips compare?

1. Unlike the 120-degree beam angle of SMD LED strips, COB LED strips have a 180-degree beam angle.
2. COB LED strips offer superior flexibility compared to SMD LED strips.
3. COB LED strips to provide uniform, dot less light.
4. COB, or chip on board, LED strips lack gold wiring, which is present in SMD LED strips.

How is the COB LED flexible strip produced?

• Initial Chip Expansion
• Die Bonding
• Placement of Resistors onto FPCB
• Reflow- Heating above 65 degrees for the final PCB with chips and resistors
• Mixing of Fluorescent Powder Glue
• Application of the mixed glue onto the surface of chips and resistors using an automatic glue machine
• Placement of glued COB LED strip into an oven
• Quality Control – testing the COB LED strip post-cooling
• Soldering the PCB into 5-meter reels or lengths as per customer requirement
• Aging test, further Quality Control, packaging, and then shipping.

Pros and Cons of COB LED Flex Strips

Having gained a fundamental grasp of the production process of the innovative COB LED strip, let’s explore its benefits and drawbacks.

Pros:

One of the primary issues with conventional LED strips is a “lighting dot” – a bright spot on the strip where the light source is visible. This phenomenon disrupts the continuity of light, creating an uneven look. A smooth and unified light source is generally more visually appealing than a strip dotted with bright spots.

In the SMD flex strips, the sizeable diodes are arranged closely to ensure a balanced light distribution over the surface when viewed from a distance. However, when the light is too close to the surface of the strip is exposed, the bright spots become an unavoidable distraction to the human eye.

With a 480 chip/M COB strip, spotting any bright spots on the flex strip becomes nearly impossible. This strip provides a soft, consistent light across its entire length. Its absence of bright spots makes the light more visually pleasing and allows it to maintain steady Lighting even in narrow areas. The only way to discern the individual lighting dot is by inspecting the back of the strip, where the individually positioned flip-chip LEDs are more noticeable. Only the individual led can be seen when the strip’s brightness is dimmed to around 5%. This quality makes COB flex strips an ideal choice for applications where:

• The LED strip cannot be concealed.
• The surface to be lit is within 2 feet of the light bar.
• Reflective surfaces like granite or glass are prevalent.
• A robust neon effect is desired.

Enhanced flexibility

These strips offer greater flexibility than other strips due to the small diodes and their evenly distributed weight. The diodes are so minute and densely packed that the strip has no unevenness. This consistency makes the strip installation easier as you no longer need to work around a protruding SMD LED. This added flexibility facilitates installation in cramped spaces and around corners.

Increased stability, reduced complications

1. The chip in a COB strip is attached directly to the FPCB without needing gold wire. A common issue with traditional SMD LED strips is the breakage of the gold wire inside the LED beads, which often results in non-illuminated chips.
2. The circuit design of the COB strip incorporates three chips, initially arranged in parallel as a group; then, each group is arranged in series to form a single strip. This design ensures that the strip emits light even if a couple of chips within a group malfunction. On a COB strip with 480 chips per meter, the non-functioning of 1-2 chips won’t create dark patches or hinder the strip’s functionality. In contrast, a single malfunctioning bead can render an entire section non-illuminated with traditional SMD strips, creating noticeable dark spots.

Expansive Light Dispersion

Typical Surface Mount Device (SMD) light strips have a luminous angle of 120 degrees, whereas the Chip On Board (COB) light strips boast an impressive luminous angle of 180 degrees.

Resistant to Vulcanization

The absence of gold wires in COB LED strips, standard in traditional SMD LEDs, allows them to resist vulcanization. This is due to the construction of SMD LED lamps, where one electrode is connected to the LED bracket via gold wire while the other is connected through silver glue. Silver tended to react with sulfides to form silver sulfide, leading to darkening and reduced LED luminous flux.

Enhanced Antistatic Ability

COB LED strips’ antistatic capability outperforms traditional SMD LED strips.

Cons: 

The lack of binning machines for COB LED strips means manufacturers rely on sampling to maintain color consistency. Ensuring that every COB LED strip falls within the 3-step color tolerance is challenging.

Reduced Luminous Efficiency

The efficiency of COB LED strips currently stands at around 120LM/W. If higher light efficiency is necessary, COB LED strips may not be the best choice.

Limited Power Capacity

If you want to learn more, please visit our website COB LED Sustainability.

The recommended maximum power for COB LED strips is only 15W per meter. This is due to the high number of chips per meter, making heat dissipation a challenge if the power exceeds 15W per meter, potentially reducing the lifespan of the COB LED strip.

Features of COB Flex Strips

By this point, the pros and cons of COB flex light strips should be clear. Here are some specifics on this type of light strip.

Segmentation and Connection: COB LED strips can be cut at marked points every 50mm (24V) or 25mm (12V), allowing customization to suit your requirements. While soldering is the preferred method of connecting the cut strips, COB strip connectors are also an alternative if soldering isn’t feasible.

Adjustable Brightness: COB LED strips, similar to standard SMD LED strips, are dimmable. You can use DALI, Triac, PWM, or 0-10V dimming power supply to achieve the desired brightness level with COB LED strips.

Varied Color Options: A range of color temperatures, from K to K, are available for white light. Other colors, such as red, green, blue, yellow, pink, etc., are also options. Moreover, tunable white, RGB, and RGBW are all available.

Mono cob led strip

CCT cob-led strip

RGB cob-led strip

RGBW cob-led strip

addressable cob-led strip

Voltage Options: 

5V(volt) cob led strip light

12V(volt) cob led strip light

24V(volt) cob led strip light

48V(volt) cob led strip light

Length Options: 

5m cob-led strip

10m cob-led strip

50m cob-led strip

100m cob-led strip

Video showcasing COB LED Strip

Tunable White COB led strip

RGB COB led strip

Connector for COB LED Strips without soldering

IP Ratings

We provide a range of choices for waterproof COB LED strips.

UV blacklights are great devices with a wide range of applications in the arts, industry, and scientific research. Unlike regular white light bulbs, UV blacklights are unique in that they primarily emit ultraviolet radiation as opposed to visible light, and as a result, there are some additional factors you will want to consider before making a purchase.

Blacklights are most commonly used when the fluorescence of objects needs to be observed, with as little visible light as possible. Generally, this means that a blacklight will emit primarily UV-A radiation, and very little visible light. Below, we discuss 4 questions you should consider before purchasing a UV blacklight.

WARNING: Always use common sense and observe safety around the use of UV lights. The amount and intensity of UV-A light energy emitted by blacklights is generally below dangerous levels, but be aware that the UV light energy emitted by the lamps is invisible. Do not, for example, look directly into a UV LED blacklight when it is turned on, even if it does not appear bright. It may not appear like much, but the dim light you see is just a small fraction of the actual UV light energy hitting your eyes.

1) Which Ultraviolet Blacklight Lighting Technology is Best?

For most applications and installations, UV blacklights are available either as a fluorescent lamp or an LED light. Until recently, fluorescent lamp blacklights were the primary option, but with rapid advances in LED technology, UV LED Lights are quickly becoming the preferred option.

Some advantages of UV LED blacklights include:

• Higher efficiency - UV LED lights are typically 1.5x - 3.0x more efficient than fluorescent UV blacklights


• Longer lifetimes - UV LED lights last for 25,000 hours or more, and do not "burn out" like a fluorescent lamp - their UV light output gradually diminishes over time. Fluorescent blacklights typically last only hours and fail catastrophically.


• No mercury or hazardous materials - UV LEDs do not have any mercury or other hazardous materials that are commonly present in fluorescent lamps. As a result, you won't need to worry about accidentally breaking a UV LED lamp and have to do any special handling of the cleanup.

Fluorescent blacklights can oftentimes be cheaper than an LED blacklight, so if you're on a tight budget, fluorescent UV blacklights might be the way to go, especially for short-term use. Don't forget to consider, however, the lifetime and efficiencies in any cost of ownership calculations.

2) How Much UV Do I Need?

UV blacklight "brightness" is a difficult metric to describe, because UV light energy is not directly visible. Although

What Is A "watt" of UV light? Watts are simply units of energy, and as you may recall from your introductory physics classes, energy can exist in a variety of forms - for example, electrical, kinetic, chemical, or light energy. In this case, we are measuring the amount of light energy emitted in the UV wavelengths.

For most basic applications, 1 watt of UV light energy output is sufficient to create strong fluorescence effects over a 100 sq ft area. For a 200 sq ft area, simply multiply the target UV levels by 2x for an estimated 2 watts of UV light energy needed.

IMPORTANT: electrical watts does not equal UV light watts! As with regular household light bulbs (e.g. 60 Watts), we are most accustomed to describing UV light bulb power in terms of its electrical energy consumption. But as is the case with household light bulbs, what matters most is the amount of light energy produced.

Unfortunately, most manufacturers do not list the UV light output, and instead simply indicate the electrical watts input. For example, you may find a product described as a 40 Watt UV blacklight, but unfortunately all this means is that the lamp consumes 40 watts of electrical energy - this does not provide us with any information about its efficiency, and how much actual UV light energy is produced. It could be a great, efficient light emitting 10 watts of UV (25% efficiency), or a terrible light with 1 watt of UV (2.5%) - we just don't know from the 40 watts power consumption alone.

If a product lists the amount of UV light output in watts, you can use this value directly to estimate your UV light needs for a space. If not, you may have to use some rough efficiency estimates.

As a rough ballpark estimate, fluorescent blacklights have an efficiency value of 5-15%. In other words, for every 100 Watts of electrical energy consumed, the blacklight will emit 5-15W of useful UV light energy.

UV LED blacklights, on the other hand, have improved efficiency values of 15-25%. For the same 100 Watts of electrical energy consumed, UV LEDs will emit 15-25W of useful UV light energy.

Because efficiency values can vary significantly depending on the quality and design of UV blacklights, try to stick with products for which you can find the actual UV light output values indicated on a product's specifications sheet. If you do want to proceed without this data, you may want to use 20% as a rough estimate for UV LED efficiency, and 10% for fluorescent blacklight efficiency.

Below is a quick lookup table based on efficiency estimates of 20% and 10% for UV LEDs and fluorescent blacklights. Keep in mind that these efficiency estimates are ballpark estimates only, and individual products can vary in their actual efficiency values.


 

Below are two examples for determining how much UV light you need:

Example 1: How many feet of realUV 395 nm LED Strips for a 200 sqft area?

We first note that the

Dividing 2 watts by 0.9 watts per foot gives us 2.2 ft.

Therefore, our estimated realUV LED strip length needs is approximately 2.2 ft.

Example 2: How many 20W UV Fluorescent Blacklight bulbs  are needed for a 400 sqft room?

For this example, we assume we do not know the efficiency value of the fluorescent UV bulbs.So, based on our rough estimate of 10%, we will estimate 2 watts of UV light output per blacklight bulb.

Our recommendation for a 100 sqft area is 1W, so you will likely want anywhere between 2-3 of these fluorescent UV blacklight bulbs that each emit 2 watts of UV, to get the UV lighting effect you are looking for in a 400 sqft area.

3) Which Wavelengths of UV Do I Need?

Ultraviolet light encompasses a wide range of wavelengths, but most blacklight applications utilize a narrow range of ultraviolet radiation (UV-A) to produce fluorescence effects - specifically between 350 and 400 nm (nanometers).

But even within the 350-400 nm range, different wavelengths can create stronger or weaker fluorescence effects. As the chart below shows, most fluorescence is strongest in the 320-380 nm range, with a peak at 365 nm.

 

Therefore, we would typically recommend a wavelength of 365 nm for most blacklight applications where maximum fluorescence is desired.

However, there are some reasons you may want to choose another wavelength. For UV LEDs, the general rule is that the shorter the wavelength, the higher the price. 395 nm UV LEDs, for example, are a common and relatively affordable option that provides decent levels of fluorescence at a more affordable price point.

The downside to these longer wavelengths is that you will likely observe lower fluorescent effects, and you may also see some more visible "dark purple" light. A common phenomenon observed is a purple shadow cast by objects - a true 365 nm blacklight would be invisible, and therefore not cast any shadows.

Typically, light above 400 nm is considered violet light - i.e. visible light that has a deep purple color, so 395 nm is the longest wavelength option you should consider for a blacklight application.

A quick way to determine how much (undesirable) visible light is being emitted by the blacklight is to find its luminous efficacy, which is expressed in lumens per watt. All else equal, a UV black light with a luminous efficacy of less than 0.5 lumens per watt is best. You can typically find luminous efficacy values listed in the

 

What Does 0.5 lumens per watt signify? Lumens is a measure of brightness, used to measure light output in standard white lights. A 40 watt incandescent bulb emits 450 lumens. Therefore, 0.5 lumens per watt means that half a lumen will be emitted for every 1 watt of electrical energy consumed.

As a concrete example: a 10 watt UV blacklight emitting 0.5 lumens per watt will emit 5 lumens of visible light - approximately 1% of the brightness of a 40 watt incandescent bulb.

 

 

Be aware that many products will not explicitly list the wavelength of UV used, or if is, it is commonly hidden in small text, where you will find out that it may be 400 or even 405 nm. These wavelengths are easier and lower cost to manufacture, and result in weaker or even nonexistent fluorescence effects than 395 nm blacklights.

 

4) What Type of UV Light Fixtures Should I Use?

Finally, when choosing a UV light fixture, you should know that they can come in a variety of shapes and forms. Below, we've listed several examples and situations where they could be useful.

UV LED Strip Light

One of the most versatile form factors is a UV LED flexible strip.

The LED strips can be cut to length in 1-inch intervals, meaning you can install these in tight spaces such as photoboxes and display cabinets. Best of all, because they operate on very low voltage 12V DC, there is virtually no electrical or fire risk.

The backside of the LED flexible strip includes a double-sided adhesive material that can be used to apply to LED strip to virtually any surface.

Because the LED strip is flexible, it can even be installed on curved or uneven places.

Purchase Waveform Lighting's realUV LED strips here.

Rigid UV LED Light Bar

Rigid UV LED light bars are similar to the LED strips, but are better suited for more permanent installations, or those requiring more robustness. They are typically available in 1, 2, or 4 ft lengths, and can be daisy chained for simplified installation.

Rigid UV LED light bars are well suited for installation on trusses, shelves, or cabinets, where the light can be installed on a straight and flat surface.

UV LED Wall Washers

Wall washer UV blacklights are designed to cover a wall surface with UV light, either to illuminate objects with fluroescence on the wall (e.g. fluorescent wall art), or to allow the UV light to "bounce off" of the wall and reflect into the entire room.

Most wall washers come in 2 to 4 ft lengths, and are designed to be mounted into the floor. The lamp itself can be adjusted so that the UV light energy can be directed at the specific angles required.

Wall washers are great for semi-permanent installations such as bars, nightclubs and event spaces where covering large, vertical surfaces is needed. Alternatively, they can be used to reflect the UV light from the wall and into the rest of the space. One of the big advantages of this approach is that it allows the UV light to disperse, creating a very even distribution of light energy. Keep in mind that you may lose some UV light energy in this process, so you may need a little extra UV light in your wattage calculations above.

 

UV LED Flood Lights

As its name suggests, UV flood lights are great when needing to "flood"  a large area with UV light. Similar to wall-washers, these fixtures typically include the ability to adjust the angle of the UV light.

Most UV flood lights are also designed for outdoor use, so for any outdoor applications requiring fluorescence, these lights are a great option. Got outdoor events and parties with fluorescent objects? Or looking to incorporate some fluorescent architectural or landscaping features? The outdoor UV LED flood will be sure to be a great fit.

When installing these flood lights, be sure to install multiple lights from multiple angles, as this will help prevent "UV shadows" where some areas don't receive enough UV light energy to produce fluorescence due to objects blocking the UV light.