Structural problems and solutions for UL certification of LED filament lamps

Recently, LED filament lamps are very popular, with 360° luminous three-dimensional light source; integrated high-voltage drive to maximize the power factor of the power supply and minimize the cost of the lamp; high-quality light source, color rendering index above 90, luminous efficiency above 110lm/W; fully transparent substrate The material is matched with the new 360°molding packaging process; the fluorescent plastic molding process has a high yield; no need to add a secondary lens; at the same time the price is lower, coupled with the user’s many years of incandescent lamp user habits, making LED filament lamps become the current The hottest LED lamp trend, many incandescent lamp manufacturers have also taken this opportunity to switch to LED lamps.

UL is the abbreviation of Underwriter Laboratories Inc. The UL Safety Testing Institute is the most authoritative in the United States and the largest private organization engaged in safety testing and appraisal in the world. If the product can pass UL, it means that product safety is known and trusted! But can LED filament lamps pass the American UL certification? What is the main problem of UL certification?

First of all, let’s take a look at the components of a general LED filament lamp:  Lamp cap + power supply + light source (filament) + lampshade (glass), which seems to be similar to a conventional LED bulb lamp. So what are the main differences between them? The main difference lies in the power supply and light source:
The power supply is a non-isolated power supply, and the working voltage of the LED filament is high voltage (above 60V)
The power supply is usually an isolated power supply, and the operating voltage of the LED light source is low voltage
UL certification is a safety certification, LED filament lamps are self-ballasted lamps, so the application for UL is also in accordance with UL1993 and UL8750 standards, so there is a test for these two lamps that is very influential, the 0.91 meter drop test! Glass is fragile, this is well known; and for LED lights, when the glass is broken, the LED lights will continue to light up, then the user may continue to use, so there is a safety problem, LED filament lights The high voltage part of the LED bulb is within reach of users and there is a danger of electric shock. Even if the glass is broken, the accessible part of the conventional LED bulb is still low voltage, so it is still a safe product and does not involve safety issues; so for the LED filament lamp , This structure is doomed to its safety hazards, and because of its characteristics is not easy to solve.

What should I do if the product wants to apply for UL certification?According to UL rules, there can be the following solutions:  1. the glass shell is replaced with a plastic shell; this kind of solution is difficult to achieve. The light transmittance of a plastic shell is much worse than that of glass, which will also affect the application of Energy Star (if required); This kind of plastic shell technology cannot reach;

2. The power supply is changed to an isolated power supply; this solution is also difficult to achieve, because the characteristic of LED filament is high-voltage operation;  Then it is stuck in a kind of problem. It is impossible to change the casing or change the power supply. How can we solve it? EMTEK-Langong provides a very good solution, which is to put a layer of transparent and elastic plastic film on the glass cover. Of course, this film must pass the UL certification; in this way, even if the drop test glass breaks However, the live part is still covered with plastic film and cannot be touched. The product is still safe. If other standard tests, such as temperature rise and component failure, also pass, the product will be able to obtain UL certification smoothly. This solution has almost no impact on Energy Star, and it can be called the best solution for LED filament lamp certification!

As a more popular luminous light source, the application range of LED filament lamp is relatively broad, which can often include all kinds of five-star and hotel and business venues, and it has better light source and breadth than traditional bulb filament. Advantage. Let’s take a look at what is the working principle of led filament lamp?
The light source structure of the led filament lamp is mainly composed of multiple parts, including the lamp holder, the base, the driving power supply, and the connection parts of the lamp beads. The common composition of these parts forms the whole of the led filament lamp. In the process of working, the LED filament lamp is mainly based on a stone substrate, and then is supplemented by a high light transmittance lampshade. At present, most of the LED filament lamps use transparent optical glass as the lamp body. This type of The lamp body can ensure that more than 99% of the light is emitted, so that the LED filament lamp can ensure the effect of lighting.

At present, many different types of LED filament lamp products have been introduced in the market. Although they all look the same in appearance, there may be differences in the dimming range. According to different occasions, the dimming range can be controlled from 10% to 90%. Putting and applying this type of new lighting products in more workplaces has a positive effect on responding to the national environmental protection and low-carbon slogan. It can also reduce the cost of decoration, and of course the quality of the light source can be guaranteed.

After understanding the working principle of LED filament lamps, will you have a deeper understanding of such a high-voltage, but low-current filament product? It is recommended that you can learn more about it online, from the working principle of the led filament lamp to the role and application scope of the led filament lamp.

Post time: Dec-07-2020