What kind of eye protection table lamp is suitable for children to use?
Children's eyesight problems have become more and more serious in recent decades, not only because of the frequent use of mobile phones, computers and other electronic products, but also because of the heavy schoolwork pressure of today's children, requiring long hours of study at desks. Most children have different degree of myopia. As an item placed on a writing desk or a dining table for lighting, a desk lamp is actually one of the important factors that affect children's eyesight. It must not be sloppy when choosing. Come and see what kind of eye protection table lamp is suitable for children to use!
1. Meet the optical performance conditions
To judge whether a desk lamp is qualified or not. Three optical performance requirements must first be met. When the writing desk lamp is in the normal working position, there are the following three main optical performance requirements.
Shading: When a person is in a normal sitting position, the inner wall of the lampshade and the light source should not be seen when the eyes look in the horizontal direction;
Desktop illumination requirements: The working area illuminated by the desk lamp should be 250lx-500lx, and the minimum illumination should be ≥120lx.
Illumination uniformity requirements: It should be ensured that the illumination in the working area irradiated by the desk lamp is relatively uniform, and no particularly bright or dark spots can be produced. Only by ensuring these three basic optical performance requirements can reduce eye fatigue and be called a Desk writing lamp.
2. Appropriate light source
Radiant light source
Thermal radiation light source is a kind of incoherent light source, which is a light source that converts thermal energy into light energy under the state of thermal equilibrium of luminous objects, such as incandescent lamps, tungsten halogen lamps, etc. The radiant light source has high color rendering and continuous spectrum. Color rendering is a measure of how close an object's color is to the color it would display under sunlight. Generally speaking, the higher the color rendering (0 - 100), the more realistic the color reproduction is. In theory, this type of light source is the most suitable.
Gas discharge light source
A gas discharge lamp is a lamp that emits light by the discharge of gas, metal vapor or a mixture of several gases and metal vapors. An electric light source that converts electrical energy into light by means of a gas discharge. In the application of table lamps, fluorescent lamps (electric rods) and compact fluorescent lamps (energy-saving lamps) are common. The gas discharge light source is relatively uniform, soft, and has high color rendering, and this type of light is also suitable for use in table lamps.
Electroluminescent light source
Electroluminescent light source is a light source that makes solid matter emit light under the action of an electric field. It converts electrical energy directly into light energy. LED lamp is a typical representative of electroluminescent light source, LED means light emitting diode. This type of light is also more suitable for use in desk lamps.
3. The lampshade should cover the lamp body
Another point that many consumers and manufacturers have overlooked is whether the lampshade can cover the lamp body. This is actually a very important factor. If the lampshade cannot cover the lamp body, the eyes will be directly exposed to strong light, which will affect the user's vision.
4. Power and luminous flux
Why is the power of the bulb so important? Because if the degree is too low, the light on the book will be darker, and it will be difficult for the human eye to read the handwriting, which will cause visual fatigue, and will lead to myopia after a long time. Generally speaking, the power It is necessary to choose more than 16 watts, but the degree of the bulb should not be too high. Excessive light will be reflected into our eyes through the white paper surface, resulting in glare, and the pupils will continue to shrink, causing eye pain and headache. 25 watts - 45 watts of incandescent brightness is the most suitable. In terms of luminous flux, it should be greater than 1200lm. Some counterfeit and inferior products use phosphors instead of luminous media. The power is very large, but the luminous flux is unqualified. Only with suitable power and luminous flux can it be regarded as a qualified desk lamp to protect eyesight.
5. The height of the lamp
The height of the lamp is also a factor that cannot be ignored. Usually, when the eyes are 30 cm away from the book, the handwriting can be clearly seen without being overly tired. Based on this calculation, the height of the desk lamp is 40-50 cm away from the writing. This will not only ensure sufficient reading lighting, but also the surrounding environment. brightness. The desk lamp is too low, the range of light exposure is small, and the surrounding is pitch black. Losing the reference object for distant vision will make the eye adjustment systems in a state of tension and compression, which will cause the eyes to feel fatigued quickly and accumulate rapidly, resulting in "light source myopia". The table lamp is too high, even if there is a qualified lampshade, it is useless. The light will also directly shine on our eyes, causing glare, and the strong light at close range will also cause light retention on the retina. Long-term eye muscle tightening is harmful to children. Their eyesight is even worse.
Another thing many consumers don't know is that it's best not to use colored light bulbs. Although colored light bulbs look cool, scientific research has confirmed that our vision is best in white light, so it is generally better to choose incandescent or frosted or LED lights that emit a soft, uniform white light rather than colored bulbs .
