? Desk lamps are a must for every family. How to choose a desk lamp? There are many mysteries in this. For children to read, you must choose with special care. The following article will introduce reading desk lamps to you in detail. needs. What color is the best desk lamp?
The most commonly used lights when people read are fluorescent lamps, light bulbs and yellow sun lamps. In principle, readers only need to sit upright and have good reading habits; and based on personal habits, no matter which color of light they choose, it will not cause great harm to the eyes.
However, for comparison, fluorescent tubes emit light through constant flickering; the degree of instability of this flickering far exceeds that of solar lamps and light bulbs. It's just like when watching TV, the picture is composed of many pictures that are continuously connected and combined.
The pupils of people's eyes will constantly expand and contract and tremble due to such flashes; therefore, it is better to use a sun lamp or light bulb when reading. How to choose a desk lamp
Light source: So far, the light sources on the market are roughly divided into four types: incandescent lamps, energy-saving lamps, fluorescent lamps, and LED lamps. ?
Advantages of incandescent lamps: no flicker, high color rendering. Disadvantages: high heat generation. (As a close-range lighting, the table lamp lasts for a long time because it is relatively close to the head. When an incandescent lamp is used as the light source, the most intuitive reaction is dry eyes and a swollen head due to its high heat generation)?
Advantages of energy-saving lamps: more energy-saving and longer life than incandescent lamps. ?Disadvantages: The light source is unstable, the color temperature is high, and it is easy to dazzle when used as close-range lighting?
Fluorescent lamps (Although some merchants claim that their desk lamps are three-primary color desk lamps, they essentially use phosphor powder as the luminous medium. The three primary colors are just a gimmick for business promotion, and because the phosphors used in the three primary colors are mixed in color, the light is much worse than ordinary single-color fluorescent lamps, so it is not recommended to use)?
LED lights: LED lights are It has a long life, is green and environmentally friendly, and its light is similar to sunlight, so it has been vigorously promoted by countries around the world. At present, it has been fully popularized in some European and American countries. Qualified LED lights have pure light, high color rendering index, and long life. Due to the nature of their light-emitting diodes, they must be powered by DC power to work. This essentially determines that they have no radiation and no flicker, and are truly Eye protection source. ?
Color temperature: There are three main commonly used color temperatures: about 3000K, about 5000K, and about 6000K.
The most common representative of a color temperature of around 3000K is an incandescent lamp. The light is yellow, making people feel warmer, but visually the brightness is not sufficient. This type of color temperature is usually used to create an atmosphere in the room. Use it more often to show a warm feeling. ?
The color temperature is about 5000K, which is the color temperature of the sun around nine o'clock in the morning. The light is yellowish, bright and does not feel dazzling. With the appropriate brightness, the light will feel very comfortable. ?
The most common energy-saving lamps have a color temperature of about 6000K. The light is pure white and visually very bright. If it is used on a desk lamp as close-range lighting, the pale light will make the People will feel it is visually dazzling and uncomfortable. ?
PS: There are some LED desk lamps on the market now that claim to have adjustable color temperature. However, since the color temperature of the LED light source is fixed by design, this type of desk lamp uses two different color light sources to adjust the color temperature. The ratio of brightness to achieve the function of changing the color of light. This kind of desk lamp should be a dimming color desk lamp in the precise sense, not a color temperature desk lamp. Also, because the light of the two colors is mixed, the light is messy and impure. It will also cause some damage 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 will be difficult for us to see. Therefore, appropriate brightness is very necessary. However, since everyone has great differences in brightness sensitivity, ordinary It is difficult for desk lamps to meet everyone's personalized needs for light. To achieve the purpose of real eye protection, appropriate brightness is very necessary, so when purchasing desk lamps, it is best to buy desk lamps that can be dimmed. (Dimmable table lamps refer to stepless dimming. Some graded dimming table lamps are essentially the same as non-dimmable table lamps. It is difficult to meet everyone's individual needs, so they are also inappropriate)?
< p> Optical processing: Because the light emitted by the desk lamp is mixed with stray light?The light emitted by the desk lamp will be mixed with other lights, and there may be glare, so reasonable optical processing technology is became very necessary. Selection criteria for children’s reading desk lamps
1. National certification requirements: Study desk lamps must pass the national compulsory 3C certification and be within the validity period;
2. Use warm white light source: color temperature 3200 -3400K, from the perspective of visual physiology, warm white light source best meets the visual physiological needs of the human eye;
3. Intuitive desk lamp: light must not be directed at or refracted by the eyes, and glare must be strictly eliminated.
The simple test method is as follows: when the height of the eye from the reading and writing desktop is 400mm and the horizontal distance from the center of the desk lamp source is 600mm, no direct or refracted light in the desk lamp shade should be visible;
4. Desk lamp illumination Intensity detection: The optimal visual light environment is when the illumination between the center of the light source and the height of the reading and writing table is 400mm 400mm between 750-1000 Lx;
5. Simple test of clarity and color reproduction: extend your palm, Put your palm upward and place it 30 centimeters under the light of a desk lamp. If you see clear lines on the palm and ruddy fingers on the palm, it means that the desk lamp has clear colors and good color reproduction; otherwise, if it is blurry, dark yellow or gray, the desk lamp has poor lighting. . Desk lamps with a color rendering index Ra above 90 have much higher clarity than ordinary color rendering desk lamps that account for more than 95% of the market share.
6. Selection of light source power: Some data claim that LED desk lamps are most suitable when their brightness is equivalent to that of 25-40 watt incandescent desk lamps, but this is actually not appropriate. After actual measurement, when the center of the light source is 400mm away from the reading and writing desktop, the illuminance of the 25-watt incandescent lamp is only 220Lx, and the illuminance of the 40-watt incandescent lamp is only 350Lx; even when the height is reduced to 300 mm, the illuminance of the 25-watt incandescent lamp is only 330Lx. The 40-watt incandescent lamp is 550Lx, which does not meet the minimum standard of 750Lx for the best visual light environment.
7. The study desk lamp should be of a certain height. At this time, the light illumination surface is large and the illumination is uniform. The illumination at a distance of 40 cm from the table should not be less than 750 Lx; the desk lamp bracket should also be of a certain length and convenient. Stretch and shrink, suitable for computer operation, drawing, calligraphy, and learning to play the piano. The fact is that it is a bit difficult to find an LED desk lamp on the market that meets all the above requirements. Therefore, many customers can only spend more than ten cents more on electricity bills every day, choosing high-definition halogen professional reading desk lamps around 3200-3400K to meet optical parameters and eye hygiene requirements.