There are numerous buyer’s guides nowadays on how to choose a desk lamp for you. Considerations include the place, interior design, the lamp’s size, style, and its functions. As an expert in high quality light source, YUJILEDSTM knows what qualities a good desk lamp should possess and always cares more about a lamp’s light quality.
Today we want to explain to you in detail the significance of a desk lamp’s light quality to your eyes and your overall experience with a perfect example we picked - Yamada Z-80PRO, a high CRI LED desk lamp.
Basically, when we talk about the light quality of a lamp, we are actually talking about these things:
Color is the human visual perception of the light reflected by objects. It is a habit formed during long-term exposure of our eyes in sunlight. If we live in a light that is largely different from natural light, our eyes will feel uncomfortable and will be inaccurate on discriminating the object’s real color. We normally use CRI (color rendering index) to assess a light source’s ability to present colors, with the value of natural light being a standard 100. If an artificial light’s CRI is near 100, it means the light quality is pretty high. The CRI includes 15 color evaluating parameters from R1 to R15. Below are the CRI test results of Yamada Z-80PRO and a P brand desk lamp, where the former has an average CRI of 97, meaning the light it emanates is extremely close to sunlight.
P brand desk lamp CRI values
Illumination is a significant parameter for evaluating a light source’s quality. Being too bright or too dark will both bring great burden to the eyes and cause eyestrain. Human eyes need lights of different illuminations in different environments, so a good light fixture is not simply about high illumination. Rather than being bright enough, a light fixture should be compatible with the environment, making the exposure zone and the ambience very close in brightness. Desk lamps are often used in dim rooms, where the ambience luminance is about 30nt. In such an environment, the ideal luminance for human eyes is 60nt to 80nt in the exposure area. Being too dark under 50nt or too bright above 100nt, the light will cause eyestrain.
In the illuminance test, the center illuminance of a Z-80PRO (70cm above the desk) is adjustable from 100lx to 2000lx. That is to say, this light can provide luminance in the range of 30nt to 600nt, ideal for all kinds of environments from total darkness to bright workplaces.
In optical design of a light fixture, multiple shadows is another vital criterion. Most LED lights have multiple light sources so as to reach the illumination requirement. Meanwhile, for better heat dissipation, every single lamp is mounted apart with certain distance to others. If the optical design is undesirable, the mixing of all light sources will produce multiple shadows. The picture below shows the shadows of a pen under a Z-80PRO and under a P brand desk lamp. We can see that there are multiple shadows under the P brand desk lamp (left), while under Z-80PRO (right), the shadow is more natural and much closer to that under sunlight. Though there is no direct evidence proving that multiple shadows are harmful to our health, it surely affects our experience and working efficiency.
Flicker is the unsteady movement of the light that causes rapid variations in brightness. Normally, human eyes can observe flicker under the frequency rate of 50Hz, some can even catch a flicker around 100Hz. Medical studies have shown that flicker under a frequency rate of 100Hz can cause epileptic seizures among highly sensitive people, and those between 100Hz to 500Hz can lead to symptoms such as headaches and eyestrains. In LED lighting, some manufactures tend to adopt cheap power design in order to save costs, and then flickers occur. Numbers of self-proclaimed flicker-free lamps are not that “free “as they said. They only eliminate the easily observable part, yet the high frequency part from 100Hz to 500Hz still exists, which are harmful to our health. So how do we tell if a lamp is flickering with a high frequency? Here is a tip for you: turn on the camera on your phone, switch to slow motion mode and focus on the lamp or the exposure area. If there are continuous variations or stripes in brightness, there are flickers. Here are two video captures taken in slow motion mode under a Yamada Z-80PRO and a P brand lamp. The Z-80PRO shows what a really flicker-free lamp is.
Flickering stripes are observed in the slow motion video under a P brand desk lamp.
No flickers are observed in the slow motion video under a Yamada Z-80PRO.
So far we have discussed the criteria of a good desk lamp from the perspective its light quality. Hope our tips can be of help when you are looking for a best desk lamp. Of course, there are other factors that will affect our decisions, especially the design. From this aspect, Z-80PRO is also excellent. It has flexible and user-friendly design with sleek and smooth lines. The simple yet beautiful style perfectly matches its characteristics and is ideal for any working or studying ambiences. That is why we highly recommend this Yamada Z-80PRO, a desk lamp which is not manufactured by us but entirely meets our standard and philosophy, to you and your family.
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