Introduction
For the prevention and control of myopia, more and more parents have begun to pay attention to, and even began to pay attention to some details, such as the reading and writing posture we often say and the purchase of a high-quality eye lamp for their own baby.
In the outpatient clinic, we often hear parents ask: When children write homework, do they need to turn on the desk lamp to the brightest? Is it not that the brighter the table lamp is adjusted, the better? Today, let me tell you about it!
We all know that a suitable light environment can not only improve the efficiency of reading and writing, but also have an important impact on visual health.
In fact, there is no only answer to the questions raised by parents, which must consider many factors in order to provide a suitable light environment.
A qualified table lamp is mainly judged from 5 aspects: illuminance, color temperature, color rendering index, strobe and blue light hazards.
illuminance
Whether the table lamp is bright enough is usually evaluated by illumination.
What illuminance is: Illuminance is also brightness. The illumination is too low, the light is dim, and it is easy to cause eye fatigue and lead to myopia.
What is illuminance uniformity: Illuminance uniformity is whether the illumination is uniform enough. When the light is uneven, the light illumination on the books is different, and the pupil needs to be constantly adjusted when the eyes move, which is easy to cause eye fatigue.
The national standard requires the illuminance and illuminance uniformity of the table lamp, which is divided into two grades: A and AA.
AA grade is better than A grade
The smaller the illuminance uniformity value, the better
Whether the brightness of the table lamp is appropriate is also related to the environment when using the table lamp, the characteristics of the reading and writing materials, and the length of reading and writing.
Temperature
What is color temperature: Color temperature represents the warmth and coldness of light, in K (Kelvin). In layman's terms, the smaller the color temperature value, the more it is biased towards yellow warm light, and the larger the value, the more it is biased towards cold light.
The color temperature suitable for reading and writing is the medium color temperature
The medium color temperature is between "warm light" and "cold light". The color temperature is too low, which is easy to cause eye fatigue; the color temperature is too high, which is easy to produce blue light damage.
The color temperature of about 4000K is equivalent to the soft sunlight in the morning, which makes people feel warm in waking up and feel the most comfortable when reading.
Color rendering index
What is the color rendering index: The color rendering index represents an indicator of color authenticity. The higher the color rendering index, the closer the color of the object is to the natural primary color in this light. We define the color rendering index of sunlight as 100.
In order to relieve eye pressure, improve the clarity of the object and the degree of color reduction, the appropriate table lamp color rendering index should reach more than 90, which can reduce eye fatigue.
Strobe
Written definition of stroboscopic: Stroboscopic is the fluctuation of the input voltage causing fluctuations in the output of light.
The definition of strobe in "some degree" (easy to understand): Looking at the screen of another appliance, the screen of another appliance will have a bright line pushing from the bottom of the screen to the top, and then from the bottom. This goes on and on, giving us the feeling that the image is flickering.
What is no stroboscopic: No stroboscopic in the absolute sense is actually impossible, and the Chinese industry standard requires 3125Hz for qualified products.
No stroboscopic > high frequency flash > low strobe
Our daily common use is 220V, 50HZ alternating current, that is, 1 second current to complete 50 times of sine waveform conversion, that is, ordinary incandescent lamps will produce 100 times of light and dark flickering phenomenon per second, every 1 flash, the pupil will contract - dilation 1 time.
Long-term learning under the strobe light, the eyes have been in a state of intense movement, which will increase the fatigue of the eyes, and then promote the occurrence of myopia.
Anti-blue light
What blue light is: Blue light is high-energy short-wave light with a wavelength of between 400 and 500 nm, which is an important part of white light.
Among them, the blue light with a wavelength of about 460 nm can adjust the amount of melatonin secretion and control the internal biological clock of the human body, which is beneficial blue light.
Blue light with a wavelength of less than 440 nm can easily penetrate the lens of the eye and reach the retina, causing photochemical action, resulting in myopia, cataracts and macular degeneration, called blue light hazards.
IEC/TR 62778 requires that the blue light hazard category of table lamps should not exceed RGl (low hazard).
The best table lamp blue light hazard category is RG0
RG0 is free of blue light hazards
Regarding the questions raised by parents, although comprehensive factors need to be considered, if you can pay attention to the 5 points mentioned above when purchasing table lamps, the table lamps can provide a suitable light environment for children in reading and writing.