Author: repairable
Source: Zhihu.
The choice of study desk lamp mainly refers to the following items. Whether LED light source is selected or not, I think the more lamps that meet the following standards, the better:
1, national certification requirements: the study desk lamp must pass the national compulsory 3C certification and be within the validity period;
2. Adopt warm white light source: the color temperature is 3200-3400K, which is most suitable for people's visual physiology.
3, intuitive desk lamp: light can not be direct or refracted eyes, strictly eliminate glare. The simple test method is as follows: when the eye height is 400mm away from the reading and writing desktop and the horizontal distance is 600mm away from the center of the lamp light source, you should not see the direct light or refracted light in the lampshade;
4. Detection of desk lamp illuminance: The best visual light environment is when the illuminance is 750- 1000 Lx from the center of light source to the height of reading and writing desk 400mm;
5. Simple test of clarity and color reproduction: put your palm up and put it 30 cm under the lamp. If the palm lines are clear and the palm fingers are rosy, it means that the lighting is clear and the color is good; On the contrary, if it is fuzzy, dark yellow or gray, the light of the desk lamp is poor. The clarity of a desk lamp with a color rendering index greater than 90 is much higher than that of an ordinary color rendering desk lamp with a market share greater than 95%.
6. Selection of light source power: It is claimed that the LED desk lamp is most suitable when the brightness is equivalent to an incandescent desk lamp of 25-40 watts, but it is not suitable. According to the actual measurement, when the center of the light source is 400mm away from the reading and writing table, the illumination of the 25-watt incandescent lamp is only 220Lx, and that of the 40-watt incandescent lamp is only 350Lx. Even if the height is reduced to 300 mm, the illumination of 25-watt incandescent lamp is only 330Lx, and that of 40-watt incandescent lamp is 550Lx, which can't meet the requirements of the minimum standard of 750 Lx for the best visual light environment.
7. The study desk lamp should have a certain height. At this time, the illumination area is large and the illumination is uniform. The illuminance at 40 cm from the desktop should not be less than 750 Lx. The table lamp bracket should also have a certain length to facilitate expansion and contraction. Suitable for computer operation, painting calligraphy and learning to play the piano.
In fact, it is a little difficult to find LED desk lamps that meet all the above requirements in the market. Therefore, many customers can only spend 10 cents on electricity every day, and choose a high-definition halogen professional reading desk lamp of about 3200-3400K to meet the requirements of optical parameters and eye hygiene.