At that time, researchers at Macwelt pointed out that when the brightness of the display reached 65,438+000 CD/m2, the use of LCD would cause visual fatigue. Dr. Wang, who studies electronic materials in Peking University Department of Electronics, said that unless the distance between the user and the screen reaches 1 m, the brightness above 300cd/m2 will do some harm to the user's eyesight. However, at present, the nominal brightness values of mainstream liquid crystal displays, such as 19 inches and 22 inches, are generally above 300cd/m2, and the models above 24 inches are generally above 400cd/m2.
Brightness is a double-edged sword. Although in the evaluation of our color analyzer, the measured data generally can't reach the nominal value, mainly around 250cd/m2, but this data still seems to be far higher than the health standard of 100cd/m2 proposed by Macwelt researchers. In that case, why do we seldom find this problem in our daily use? The author believes that the wrong use habits are the root cause. Even if the brightness of our display exceeds 500cd/m2, as long as our eyes are used to this brightness, when we adjust the brightness of the display back to 200cd/m2, we will think that the brightness of 200cd/m2 is too dark. It is this wrong habit that makes the damage of high brightness to our eyes happen invisibly. Second, what is a healthy light? Investigation of liquid crystal brightness in the market The author conducted a simple investigation on more than ten liquid crystal displays in our PConline evaluation room, and found that the default brightness of most liquid crystal displays is 100%, and only a few products with very small brightness are set to 90%, such as AOC9 17Fwx, and none of them have a default brightness below 90%. Why do manufacturers like to set the brightness to 100%? In fact, the reason is very simple. Higher brightness can make people feel that the display screen is more gorgeous. The pursuit of brightness parameters itself comes from TV sets. At present, the brightness of LCD TV is generally above 500cd/m2. And some special technologies, such as dynamic contrast and local brightness enhancement, all contain the pursuit of high brightness more or less. However, when many consumers buy LCD monitors, they usually take the first feeling at the purchase site as the judgment standard, and the default high brightness can make consumers leave a good impression on the products.
The default brightness 100% is almost an industry standard. Where is the healthy and practical brightness? According to Macwelt's research, when the brightness of the display reaches 100cd/m2, using LCD will cause visual fatigue. However, the author made a simple attempt. When the brightness level is around 100cd/m2, the picture is obviously dark, and some dark scenes can hardly be displayed well in the game. Therefore, the author thinks that the brightness of 100cd/m2 is based on CRT, and this brightness standard should be improved for LCD. Therefore, the author estimates that the healthy brightness in LCD should be between 120cd/m2 and 150cd/m2. How to adjust the best brightness? Now that we have determined that the healthy brightness should be between 120cd/m2 and 150cd/m2, we can have a real brightness level. However, as long as the netizens who are more concerned about our monitor evaluation believe that the brightness of the monitor also has a parameter of uneven brightness. Due to the arrangement of lights in the display, the brightness of each point in the display is different. Generally speaking, the highest brightness is in the center of the screen and the lowest brightness is at the edge of the screen. The so-called brightness inhomogeneity is the brightness ratio of the lowest brightness point to the highest brightness point of the display. Generally speaking, the brightness unevenness of 75% is already an excellent level. However, with the improvement of liquid crystal manufacturing technology, the brightness unevenness of mainstream products on the market has generally reached more than 80%. Therefore, in this exploration of healthy brightness, the author conducted it according to 80% brightness unevenness. According to this calculation, after adjustment, when the LCD is set to a relatively healthy and practical brightness, the brightness at the midpoint of the screen should be between 150cd/m2 and 187.5cd/m2. Third, the first step is to try: is the brightness of the same product? For the brightness test, there is no doubt that we need to use our professional instruments and equipment: Konica Minolta CS-200. In this evaluation, the author first adjusted the background to white, and then measured the brightness of the midpoint of the screen with a color analyzer. At the same time, the brightness parameters in the OSD menu of the display are adjusted and tested at 100%, 80%, 60%, 50%, 30%, 10% and 0% respectively.
Evaluation of professional instruments and equipment used: Konica Minolta CS-200 In order to make readers more convenient to understand how to adjust the healthy brightness, the author tries to discuss a question first: If the nominal brightness values of monitors are the same, should their optimal brightness settings be the same? In order to verify this point, the author made a comparison with hannspree's spherical liquid crystal.
Hanshi Prey Ball Series Liquid Crystals Three Hanshi Prey Ball Series Liquid Crystals are basically the same except for their appearance. The author also made a simple test of its display effect, and the performance of the three is almost the same with the naked eye. So can the same three LCD monitors really achieve exactly the same effect under the same settings? In order to save time, the author only tests the midpoint of the display. Brightness contrast (unit: cd/m2) at the midpoint of Hannspree ball series liquid crystals As mentioned above, when the brightness setting is ideal, the brightness value at the midpoint of the screen should be set between 150cd/m2 and 187.5cd/m2. According to the actual test data, there is not much difference between the OSD brightness of these three hannspree ball series LCDs at 60% and 100%. However, at low brightness, the decline is large, and the lowest brightness is about 70%. In this test, we found that the OSD brightness level effect of these three ball series liquid crystal displays in hannspree is not very ideal, but the range of the highest brightness and the lowest brightness is quite large. At the same time, the author found that the brightness of the same LCD is still different under the same settings, but the difference is not big. Because in the actual evaluation, every brightness of the display is different, even the same point will be different under slight interference, so the appropriate brightness parameter difference is acceptable. Generally speaking, we can see that if the brightness value of the midpoint of the screen should be set between 150cd/m2 and 187.5cd/m2 under the all-white background, then the brightness should be adjusted between 25% and 28% for hannspree spherical LCD. So what about other brands of LCD monitors? Fourth, the best brightness survey In this survey, the author selected three LCD monitors from different manufacturers, namely AOC 9 17Fwx, Samsung T200 and LG2252TQ. The three products have different sizes, but their nominal brightness values are all 300cd.m2, and they all use TN panels. What will happen to the brightness performance of three different liquid crystal displays? In the test method, the author adopts the same method as the above-mentioned hannspree spherical LCD test. In the general survey of mid-point brightness (unit: cd/m2) under all-white background, it should be noted that the default brightness of AOC9 17Fwx is 90%, the brightness parameter is 254.24%, and the default brightness of the other two products is 100%. From the survey results, we can find that among the three products, Samsung T200 has the widest brightness range, which can reach between 299.25cd/m2 and 35.63cd/m2, which is quite exaggerated. And the brightness levels of the three products are also close to linearity, and the OSD adjustment is good. According to the above, if the brightness value of the midpoint of the screen should be set between 150cd/m2 and 187.5cd/m2 under the all-white background, the brightness to be adjusted for the three products is different, and it is generally concentrated at about 50%. Of course, this data is for reference only, and different users may have different visual habits. V. Summary of the evaluation room: Calling for the promotion of 50% brightness From this survey, we found an amazing fact: LCD is killing our eyes! High brightness can really make the picture look brighter, but too high brightness will cause permanent damage to vision. At present, the default brightness of most liquid crystal displays on the market is 100%, but the brightness at this time is as high as 270cd/m2 to 300cd/m2, which has reached a "dangerous" level. The author believes that high brightness is just a point, and what is even more terrible is everyone's wrong usage habits. This misconception has caused many people's eyesight to be murdered unconsciously. Theoretically, if the brightness of the display is below 100cd/m2, we will feel less visual fatigue in practical use. But I think this healthy brightness should be based on CRT display. In practice, the author thinks that the brightness of 100cd/m2 is really too low, even when processing documents, I feel a little uncomfortable. So I personally think that the brightness from 120cd/m2 to 150cd/m2 should be healthy and practical for LCD. However, considering the problem of uneven brightness, the author thinks that it is a good scheme to set the brightness value of the midpoint of the screen between 150cd/m2 and 187.5cd/m2 under the all-white background.
In the fluorescent light environment, 50% brightness (right) is actually more comfortable than 100% brightness (left). In this survey, the author found that the OSD adjustment effect of different models of LCD will be very different. In the ball series products of hannspree, 50% of the brightness setting is still as high as 250cd/m2 in the actual test. Therefore, for different brands and models of products, specific problems need to be analyzed to adjust the health brightness. But in the comparison of AOC, LG and Samsung, we still found the intersection of healthy brightness, 50%. The author himself recently adjusted the brightness level of the monitor he used to 50%, and there was no discomfort or other problems affecting his work in practical application. In fact, strictly speaking, the brightness can also be fine-tuned by adjusting the contrast, but after the author's own verification, the effect has not changed much, which has a great impact on image performance. Interested readers can study it in depth. For the sake of China people's eyesight, I hereby appeal to everyone to pursue high-quality display effects, and also appeal to major LCD manufacturers to reduce the brightness level of their LCD monitors to below 50% for the sake of consumers' eyesight, and also appeal to major LCD manufacturers to reduce the default brightness to below 50%. I will try to add the indicator of healthy brightness in the future evaluation, hoping to give some help to netizens.