What color desk lamp do you choose? When reading a book, the most commonly used lamps are fluorescent lamps, light bulbs and yellow sun lamps. In principle, readers should have a correct sitting posture and good reading habits; Then according to personal habits, no matter which color of light you choose, it will not cause great harm to your eyes.
However, in contrast, fluorescent tubes are constantly flashing; This unstable flicker is far more than solar lamps and light bulbs. Just like watching TV, the picture is composed of many pictures, which are constantly connected and combined.
The pupil of a person's eyes will tremble because of such a flash, constantly expanding and shrinking; So when reading a book, it is better to use a sun lamp or a light bulb.
How to choose the light source of lamps: Up to now, there are four kinds of light sources on the market: incandescent lamp, energy-saving lamp, fluorescent lamp and LED lamp. ?
Advantages of incandescent lamp: no stroboscopic, high color rendering. Disadvantages: high calorific value. As a close-range lighting, the desk lamp is used for a long time because it is close to the head. When using incandescent lamp as light source, the most intuitive reaction is dry eyes and bloated head, because its heat is too large.
Advantages of energy-saving lamps: compared with incandescent lamps, energy-saving lamps save electricity and have a longer life. ? Disadvantages: the light source is unstable and the color temperature is high, which is easy to dazzle as close-range lighting?
Fluorescent lamp (although some merchants claim that their desk lamps are tricolor lamps, they use fluorescent powder as the luminous medium in essence. Tricolor lamps are just a gimmick promoted by merchants, so tricolor lamps are not recommended, because the fluorescent powder used is mixed color and the light is much worse than ordinary monochromatic fluorescent lamps)?
LED lamp: LED lamp is widely promoted all over the world because of its long life, environmental protection and similar light to sunlight. At present, it has been popularized in some European and American countries. Qualified LED lamp has pure lines, high color rendering index and long service life. Moreover, due to the nature of its light-emitting diode, it must be powered by DC, which essentially determines that it has no radiation and stroboscopic light, and is a real eye protection light source. ?
Color temperature: There are three commonly used color temperatures: about 3000K, about 5000K and about 6000K K. ..
The most common representative of color temperature around 3000K is incandescent lamp. The light is yellow, which makes people feel warmer, but it is not bright enough visually. This color temperature is usually used to create an atmosphere, and it is used more in the room, showing a warm feeling. ?
The color temperature is about 5000K, and the color temperature of sunlight is about 9 am. The light is yellow, bright and not dazzling. If the brightness is right, the light will feel very comfortable. ?
The color temperature is about 6000K, and energy-saving lamps are the most common. The light is pure white and visually feels bright. If it is used as short-distance lighting on a desk lamp, it will make people feel dazzling and uncomfortable visually because of its pale light. ?
PS: There are some LED desk lamps with adjustable color temperature on the market. Because the color temperature of LED light source is fixed in design, this desk lamp uses two light sources with different brightness to realize the function of changing the color of light. This kind of desk lamp should be a dimming desk lamp in an accurate sense, not a dimming desk lamp, and its light is mixed with two colors, which makes its light messy and impure, and will also cause certain harm to the eyes. ?
Brightness: Appropriate brightness can make the light softer and more comfortable. ?
If the brightness is too bright, we will feel dazzling, if the brightness is too dark, it is difficult for us to see things clearly, so appropriate brightness is very necessary. However, because everyone's brightness sensitivity is very different, it is difficult for ordinary desk lamps to meet everyone's individual needs for light. In order to really protect the eyes, the appropriate brightness is very necessary, so it is best to buy a desk lamp that can be dimmed when buying a desk lamp. Dimming desk lamp refers to stepless dimming. Some desk lamps with graded dimming are essentially the same as those without dimming, so it is difficult to meet everyone's individual needs, so it is not suitable?
Optical treatment: Is the light emitted by the desk lamp mixed with stray light?
The light emitted by the desk lamp will be mixed with other light, and there may be glare, so reasonable optical processing technology becomes very necessary.
The selection standard of children's reading desk lamp is 1, and the national certification requirements: the learning 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.