At present, there are many kinds of table lamps on e-commerce platforms, and the prices range from dozens to thousands of dollars. There are even table lamps that are advertised under the banner of "eye protection". The public wants to choose a qualified and suitable table lamp. It's very difficult. What is the difference between these lamps with such a big price difference? What parameters should we pay attention to when buying? I will explain them one by one today.
1. It is very important that the desk lamp is bright enough
The brightness of the desk lamp refers to the "illuminance and uniformity of illuminance" in the national standard. Studying in low light for a long time can easily cause visual fatigue, which in turn will induce myopia, so the brightness of the desk lamp cannot be ignored.
According to the national standard GBT-9473 2017 "Performance Requirements for Reading and Writing Table Lamps", the table lamp should meet the A-level or AA-level standards. The light emitted by the desk lamp that meets these two standards will be more uniform on the desktop, and the coverage area is wide, the light will not converge in a small area. In this way, the situation of "one area is bright and one area is dark" will not appear when reading a book. Because our eyes adjust the pupil size according to the amount of light incident, if the above situation occurs, our eyes will constantly adjust the pupils during the reading process, so that our eyes will be prone to fatigue, which may cause fatigue in the long run. Cause myopia.
Whether a table lamp can meet the illuminance standard has a lot to do with the luminous source. The cost of producing a luminous source that meets the conditions is high, and the price of this type of table lamp is relatively high. Although many low-cost desk lamps claim to have uniform light emission and large light output, and can reach the national A-level standard, there is no relevant test report on the page, which is obviously false propaganda. The higher-priced table lamps will clearly indicate that they have passed the national A/AA level test, and the relevant report will be attached.
When purchasing a desk lamp, it is necessary to see if the desk lamp has enough brightness, it is best to choose a desk lamp with A/AA certification.
2. Mobile phone strobe measurement is not reliable
We all know that harmful stroboscopic damage to the eyes is very serious, especially now that the light source and screen are seen everywhere, and since the mobile phone camera is powerful, many people say that using the mobile phone can check the stroboscopic status of the light source. If you can't see the black bar that keeps flashing on the phone, then this light source has almost no stroboscopic damage.
Therefore, many businesses will use this point of view to promote their desk lamps, telling consumers that as long as the mobile phone cannot be seen, there is no flicker.
But this statement is wrong, because the mobile phone is only a reference tool, it is not professional, the camera will be affected by many factors, you can use the mobile phone camera as a reference, but it can not be considered as free of flicker.
Table lamp CQC national standard stipulates that for a table lamp with "no visible flicker", the fluctuation depth of the light source output waveform should be less than or equal to 0.08/2.5xf(90Hz
3. Dozens of desk lamps can be anti-blue light?
The harmful blue light we usually call refers to high-energy short-wave blue light with a wavelength range of 420-460nm. Blue light is ubiquitous in everyday lamps and light sources. If the light source is particularly bright and white, the proportion of blue light may be too high. When blue light reaches a certain intensity, it enters the retina and may cause damage to the retina. Those desk lamps with a high proportion of blue light must not be selected.
Many desk lamps will be written on the promotion page to effectively reduce blue light, but many of them use a simple blue light filter or directly coat the LED lamp beads with phosphor. Although this can indeed greatly reduce costs, the problem is that this method has a very low effect on reducing blue light, because white light LEDs contain high-energy short-wave blue light, which cannot be effectively filtered by phosphors and filters. Moreover, the light will pass through the phosphor or blue light filter layer and then diverge through the panel, which will lose a lot of light effect, and the light will not be bright enough, and the real color of the illuminated object will be greatly reduced.
The CQC national standard of table lamp also clarifies the assessment of the "blue light hazard" of LED table lamps. A qualified table lamp should reach the non-hazardous category (RG0), so when buying a table lamp, you should choose a product with CQC certification.
4. Color reproduction is also very important
Color restoration is a very important step in the correct recognition of objects. The professional term is color rendering index, which is an important indicator used to measure color rendering. Under different light sources, the colors we see are different.
When purchasing, we also need to consider the color rendering index of the desk lamp. The higher the color rendering index, the closer the light is to sunlight, and the higher the color reproduction of the object. Because when we read, write, and work under a desk lamp, there will be various colors on the books and computer screens. If the color rendering index of the desk lamp is low, we think it is such a color in our perception, but in fact But it is not, it will cause cognitive errors.
When we buy a table lamp, the color rendering index of the table lamp is generally greater than 85. If you want to do something with high color requirements like painting under a desk lamp, it is recommended that the color rendering index of the desk lamp be at least 90.
Summary: There are many types of desk lamps in the market. We do not have a hard standard to refer to when buying desk lamps. After we have mastered these parameters, we can choose a qualified and excellent desk lamp before purchasing. Reduce damage to the eyes, thereby protecting our eyes and protecting our eyesight.
