Are Flickering LED Lights Dangerous?

After more than ten years of development, the LED lighting industry has shifted from prioritizing light efficiency, energy saving, and cost to focusing on light quality and health. In recent years, the retinal damage caused by LED lighting has become more evident, prompting the industry to recognize the urgent need for healthy lighting. When evaluating the impact of LED light sources on the human eye, addressing flicker is inevitable. As electric light source technology advances and our understanding of light biology deepens, resolving the flicker problem is crucial for achieving healthy lighting.

1. What is flicker?

Flicker refers to fluctuating the luminous flux of an electric light source at a specific frequency. 

2. Why do LED lights flicker?

LED lighting products use AC to DC constant voltage or constant current power supply drive. The light source itself does not produce flicker; rather, flicker effects depend on the LED driver. Due to the wide variety of drivers, the stroboscopic performance of each LED product is not the same. Some manufacturers use relatively simple drive circuits to save costs, which can lead to a larger stroboscopic problem. Poor quality light sources with chips less than 1W and falsely advertised wattage can also result in driving chip mismatch and abnormal operation, leading to strobing.

Dimming is essential for intelligent lighting products and can cause stroboscopic effects. When the product has a dimming feature, stroboscopic effects can be worsened, especially at lower dimming levels. Therefore, lighting products with dimming capabilities or those designed with dimming controllers should be tested for stroboscopic performance at both their brightest and lowest dimming levels.

3. What is the danger of flicker?

The human eye is a complex system with significant individual differences. However, most people can detect light flicker below 80Hz, known as visible flicker. Visible flicker is not acceptable for normal lighting or display. Beyond 80Hz, the human eye has difficulty detecting flicker, but it still impacts spatial perception. This effect is thought to persist up to 500Hz.

What are the potential harms of prolonged exposure to flickering LED lights for people who work or live in such an environment? The primary risks are related to human health and safety from chronic exposure. These risks may include headaches, migraines, fatigue, increased eye pressure, reduced visual efficiency, blurred vision, decreased attention, and neurological problems such as photosensitive epilepsy. Various studies have demonstrated the adverse effects of stroboscopic impact on human physiology and psychology, most notably damage to vision, emotional irritability, and induced epilepsy. These effects can be caused by various sources, including optical illusions, rotating machines, road lighting, and car lights.

4. How can we detect if LED lights are flickering in everyday life?

Ordinary people don't have professional equipment, but a simple and easy testing method is to use the mobile phone camera to aim at the lighting product being tested and observe if stripes are on the screen. This can help determine if the product is flickering. While this method may not be entirely accurate, it can highlight certain issues and is suitable for regular users. Professional testing equipment is necessary for a more thorough evaluation.

5. How to avoid flicking LED lights?

When purchasing lamps, it's important to select professional LED lighting brands, such as Tangtang Lighting. You can use the method mentioned above with a mobile phone camera to help detect any lighting issues. It's best to ask the seller for a relevant test report, such as the China Quality Certification Center (CQC) certification. This will help reduce the risk of buying flickering LED lights and ensure the safety of your family's health.