In daily life, although people don't talk about "spoke" discoloration, they are also sincere and fearful. After all, long-term contact will cause harm to the body. Therefore, people always choose low-radiation or non-radiation products when purchasing home appliances. Among the many home appliances, TV is the most frequently contacted by adults and children, so its radiation problem has also received much attention. LCD TV "no radiation" seems to be well-known, because from the first day of LCD TV market, the business tears the throat and shouted: "LCD TV zero radiation." So, is the LCD TV really free of radiation, can we watch it for a long time at close range?
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First, is the LCD TV really zero?
In theory, the display material of the traditional CRT TV is a phosphor, which is displayed by the impact of the electron beam on the phosphor. The electron beam will generate strong electromagnetic radiation in the moment when it hits the phosphor, although many CRT TV products are currently being processed. The radiation problem has been treated more effectively, and the amount of radiation is minimized as much as possible, but it is difficult to completely eliminate it. Relatively speaking, LCD TVs have their own unique advantages in the prevention of electromagnetic waves. It uses a strict sealing technology to enclose a small amount of electromagnetic waves from the drive circuit in the display screen. Theoretically, there is no radiation. In order to dissipate heat, the ordinary display screen must make the internal circuit contact with the air as much as possible, so that the electromagnetic waves generated by the internal circuit are "leaky" to a large extent.
The most authoritative radiation evaluation report implements the five-point system. Anyone who is rated as five points is seriously over-standard and needs to be paid attention to; Samsung and above are also beyond the scope of the standard and need to pay attention; one-star is safe and can be used with confidence. Electromagnetic radiation is divided into two levels, in which the unit of the working frequency band is μT. If the radiation is above 0.4μT, it is a strong radiation, which has certain harm to the human body, and long-term exposure is prone to leukemia. If the radiation is below 0.4μT, it is relatively safe. The unit of radio frequency electromagnetic wave is μW/cm2. The radiation evaluation report shows that the LCD TV, whether it is in the front half meter or the front 3 meters, the test results of the instant start, normal viewing, channel change, and standby state are 0.1μT, and the side is only 0.11μT, basically There is no change in the intensity of the radiation. In a series of radiation tests on traditional TV, LCD TV, plasma TV and rear projection TV, LCD TV and rear projection TV have the least radiation, plasma TV is slightly stronger, and traditional CRT TV CRT has the largest radiation.
The above data is not to say that LCD TVs have no radiation at all, and people can purchase and watch with confidence. But in fact, some people with common sense know that a magnetic field is generated when electricity passes through a conductor. Therefore, for radiation damage alone, LCD TVs do not have as much radiation damage as CRT screens. Its radiation itself is smaller than that of a picture tube, but it is impossible to say that there is no radiation at all. It is an electronic device after all. It has many internal circuit devices in addition to the liquid crystal panel itself. At best it can only be said to be "low radiation" rather than "zero radiation." The principle of radiation is that a current generates a magnetic field, a magnetic field generates an electric field, and an electric field generates a magnetic field in an infinite loop. Moreover, the LCD TV screen is larger than the commonly used TV screen, so according to the total radiation area of ​​the LCD TV, the radiation is still inevitable.
Second, the radiation of large LCD TV
1, miscellaneous LCD TV
The size of the LCD TV radiation is related to its manufacturing process and quality. Some low-quality miscellaneous LCD TVs will generate strong electromagnetic waves. According to the relevant departments in 2006, some LCD TV radiation was actually measured. The results show that some small brands of LCD TV radiation is seriously exceeded, the main reason is that there is no shield inside. The shield is an alloyed metal cover that is essential for reducing TV radiation. The components such as the internal circuit board of the TV emit high-intensity electromagnetic radiation during operation, and the shield can act as a shield to shield most of the electromagnetic waves in the cover, thereby protecting the user from electromagnetic radiation. Therefore, when purchasing an LCD TV, it is best to choose a big brand and observe whether there is a shield.
2, too much LCD TV
At present, most LCD TV manufacturers on the market are paying too much attention to emphasizing their multimedia functions, digital signal receiving functions and fashion appearance features. Due to excessive additional functions, the power consumption and operating power of the display are increased, to some extent. Increased the amount of electromagnetic waves emitted and the consumption of resources, increasing the possibility of radiation.
3. Exceeding the service life or used LCD TV
LCD TVs are durable consumer goods, but they are not equal to "long-lived consumer goods". They should be "retired" by the end of their useful life. Because the product aging will have a variety of problems: First, the insulation aging, resulting in leakage, resulting in electromagnetic pollution; Second, the component technical indicators are seriously reduced, leading to the leakage of harmful substances; Third, the "overdue service" TV radiation will also increase. LCD TVs are generally used for 8 to 10 years, and LCD TVs that have passed this safe period will increase security risks. In addition, should buy new LCD TVs as much as possible, generally do not use second-hand LCD TVs, because it is understood that many second-hand LCD TVs allow merchants to change their face, the possibility of component radiation is greatly increased, under the same distance, similar models, Second-hand LCD TV radiation is generally 1~2 times that of new computers.
Third, prevent LCD TV radiation tips
1, maintain a certain viewing distance
The radiation range of a TV generally refers to the length. The radiation range of a liquid crystal television is generally within 2 meters, and the viewing distance of a flat-panel TV of 42 inches or more is not affected by radiation. In addition, if you watch the big screen at a close distance for a long time, it will cause visual fatigue. Therefore, you should consider the size of the room when you buy it. The general viewing distance is between 2 and 2.5 meters, and the choice of 29-inch products; 2.5 to 3 meters, can choose 34-inch products, 3.5-meter or more can choose 37-inch or more than 40-inch products.
2, reduce dust, reduce radiation
The LCD TV is dusty, and many people think that this is just a health problem. The truth is not that simple. Studies have shown that dust is an important carrier of electromagnetic radiation. If your LCD TVs are not wiped often, then even if they are turned off, the electromagnetic radiation remains in the dust and continues to harm your health. Therefore, it is best to wipe the LCD TV frequently to remove the dust, and also remove the electromagnetic radiation trapped inside, which can effectively prevent the health hazard of radiation. In addition, dust can often overload electronic components, boards, and heat sinks, ultimately resulting in increased power consumption and even burning of electronic components.
3, as much as possible next to the LCD TV
Although LCD TVs have less radiation, many of them are high-radiation bodies. Therefore, try not to place too many electrical appliances near the LCD TV. For example, refrigerators and TV sets should be as far apart as possible, in addition to avoiding the influence of these electrical appliances when watching TV (their radiation range is wider than LCD TVs). Also avoid magnetic field interference. Another example is that the TV and the audio speakers need to be kept at a certain distance. Don't rely too close, because there are speakers with large magnetism in the recorder and speakers, and a strong magnetic field is formed around them. This magnetic field will also directly affect the LCD. The electromagnetic field of the TV. In addition, do not place any metal objects in the room to avoid the re-emission of electromagnetic waves.
4, let the green plants share the radiation
Any animal, plant or human body has the natural ability to absorb radiation, so we can put some green plants next to the LCD TV to reduce radiation. However, there are certain restrictions on placing green plants next to LCD TVs, because many LCD TVs do not have waterproof protection, and the internal circuit board of the heat dissipation grid will directly contact the outside air. If the water vapor plant or excessive green plants placed next to the LCD TV will seriously affect the safety and service life of the appliance. Therefore, it is best to place a drought-tolerant green plant like a prickly pear, cactus or aloe vera near the LCD TV.
5. Drink tea while watching TV.
Experts believe that drinking green tea can play a certain role in anti-radiation. Vitamin C and vitamin E, especially tea polyphenols, contained in green tea have strong antioxidant activity and can eliminate oxygen free radicals in the human body. It plays a role in resisting radiation and enhancing the body's immunity. In addition, the tea contains carotene, which can be converted into vitamin A under the action of the intestinal wall and the liver, and vitamin A has the effect of nourishing the eyes, relieving eye fatigue, and preventing night blindness. In addition, the radiation generated by the TV screen can cause the human body to dry and lack water, and accelerate aging. Therefore, in the process of watching TV, you may wish to soak a pot of tea, which can both resist radiation and hydrate the body. If you are not used to drinking green tea, chrysanthemum tea can also play a role in resisting computer radiation and regulating body functions.
6, turn off the TV, beware of radiation accumulation
Although the LCD TV has less radiation, the radiation still exists. Therefore, when the LCD TVs are suspended, it is best not to let them be in the standby state, because a weak electromagnetic field can be generated at this time, and radiation accumulation occurs for a long time.
Fourth, test LCD TV radiation
Radiation is a colorless, odorless and invisible sound wave, then how can we know the LCD TV radiation, such as when the radiation is large, when is the radiation is small? If it is not practical to buy a radiation tester, then the following method It saves both money and effort. Usually the test of LCD TV or other appliances radiation size, the easiest way is to take a small radio, adjust to the middle wave band, move around the various open appliances, the more serious the interference indicates the greater the radiation, this method is a hundred test, You may wish to pick up your radio and test your home appliances.
Fifth, the real harm of LCD TV
The "zero radiation" advertised by LCD TV manufacturers is not credible. We have already said that LCD TVs also have electromagnetic radiation. It mainly comes from the oscillating circuit of backlights. However, since measures to prevent electromagnetic radiation are adopted, The display of a normal picture tube is smaller. For the radiation of LCD TVs, if you do a good job of preventing radiation, then the damage caused by LCD TV radiation is very little. The biggest harm to LCD TVs is radiation, but eye fatigue.
Ophthalmologists say that watching high-brightness LCD TVs for a long time will bring two major hazards to the eyes: First, visual fatigue, symptoms such as eyelids, heavy eyelids, etc., and even dizziness, nausea, vomiting, and "video terminal" The second is due to the massive consumption of the photoreceptor of the retinal stem cells of the eye - rhodopsin, causing temporary loss of vision, which is more likely to cause myopia for children who are still in the growth stage. How to prevent the high brightness of the LCD TV, in addition to the appropriate viewing time, but also has a lot to do with the indoor light source, this issue will be discussed in detail later. In general, for LCD TVs, in addition to radiation protection, it is necessary to prevent high brightness from bringing damage to the eyes.
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