Hello everyone I am Qingbing In our daily life Among the visible light There are two factors Is recognized Can cause harm to human eyes One is Blu-ray One is flat voice Which one of these two factors The damage to the eyes is greater Let's make a comparison First talk about Blu-ray It's everywhere As long as we see those shiny objects Basically have blue light It especially exists in High light Brighter part For example, in nature
twenty one
00:00:30,960 --> 00:00:31,400
sun
twenty two
00:00:31,400 --> 00:00:32,560
It has blue light
twenty three
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Moderate blue light
twenty four
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In fact, it is good for our health But if the blue light is exposed It’s just that the eyes are exposed to it for too long Too many words If the light is too strong Health To the eyes Cause irreversible damage Before smartphones became popular People staring at a luminous body Watch for so long like now That doesn't exist Phone screen Of course, including tablets or computers These similar screens The blue light they emit How harmful is it to human eyes We go to a more authoritative place Take a look at The website of the Society of Ophthalmology This is the website of the American Academy of Ophthalmology aao.org Now let's search Articles on Blu-ray Because it is in English So also Search only in English All right Found more than 1,000 articles Then the first page Just some relatively new articles We didn't watch them all We only choose two at random Take a look I have already chosen This is my random choice Is based on the title Didn't choose it specially Let's take a look What do these two articles say This article is discussing Should you worry about blue light Then here is a picture of a computer Obviously it is talking about Blue light from electronic products In the first paragraph This is no scientific evidence to prove Blue light from electronic products Can cause damage to eyes We basically don’t need to watch it later Actually its content is similar That's it Cited some experiments I also interviewed some ophthalmologists I said there is no evidence Can prove From electronic products Blue light Can be on the eyes Direct harm It also specifically mentioned No matter if you are from electronic products How much blue light watched Actually not as good as you from the sun Blu-ray seen more that is Not as blue as the sun Causes more damage to the eyes But also mentioned If the child looks at the sun If you don’t get enough sun Then for the growth of the eyes Development of vision It's also very harmful So it must be moderate Mentioned throughout the article Watching the computer hurt There are only two for eyes One is to cause dry eyes And the tension of the eye muscles Make eyes uncomfortable The second is to watch too much at night Computer tablet or mobile phone will affect sleep It made two suggestions for this The first one is the three 20 principles 20 20 20 principle The first 20 means Every 20 minutes Then put the eyes Just move away from your electronic device Look at an object 20 feet away 20 feet is about 7 meters And then watch for at least 20 seconds like this It will make the eyes less dry not easy Very tight Very uncomfortable Feeling swollen Advice on causing insomnia at night Just sleep online The first two or three hours Don't look at the phone it is good We look at the next article The title of this article is more straightforward. No No such thing The blue light released from your phone Won't make you blind Then read the title Actually basically Also know What kind of meaning After I read this article, In fact, he and the previous article The content is almost the same But it has a special hint It said that although the current No experimental proof Blu-ray of electronic products Harmful to human eyes But these experiments so far Are still just experiments in the laboratory Because we are Pay attention to the harm of human eyes Especially the blue light of electronic products The attention to human eye hazards is not long This article specifically mentioned here These cells in the experiment Not extracted from the eyes So this is just a laboratory experiment It does not fully prove We are in reality Look at the phone Will not cause harm So for the sake of safety If you have questions Or feel that there is a problem with the health of your eyes It’s better to ask your ophthalmologist I saw the American Academy of Ophthalmology After some articles I just showed you two articles Actually I have read more than two articles myself I read about seven or eight articles Then add the browsed Unfinished Flipped through There are probably a dozen or twenty articles in total Actually the experiment so far It's still rough So scientists Also keep one More cautious We think if it really comes from the computer screen Or blue light is released from the phone screen Has been fully confirmed If it is not harmful to human eyes Why do you want to do something So-called low blue light certification So now is a very cautious attitude Although not found Proof Can directly damage the eyes But no evidence was found Can directly prove No harm at all you need to know If the scientist wants to prove the computer screen Or phone screen Is harmful to the eyes He basically can't get any funds or funding You said that electronics companies are making money now Very rich They will fund an ophthalmology institution Do research Then prove that these screens he produced Or the screens he sells Is it harmful to human eyes? He wished you would not prove right He is eager to give you money Do other research Or you have to do this research I'll give you money Don't do it You do other research, OK? This also reminds me of one thing Precisely because i saw So many consistent articles All said no evidence was found Prove that he hurts the eyes This blue light is harmful to the eyes Reminds me of America Decades ago At that time, many doctors said Smoke can prolong life Of course at that time Tobacco companies are also booming It happens that the tobacco company is very rich A very powerful era All right Blu-ray Let's talk about strobe Strobe is different from blue light It's not all electronic devices All luminous things have stroboscopic lights For example, the sun does not flicker Because it is always on Mobile computer screen Some LCD screens are not strobe Oled's must be flat But not LCD There must be no strobe It may also have stroboscopic mainly depends on Way of dimming Current dimming methods of electronic products There are mainly two One is DC dimming One is PWM dimming LCD-like screen It can use the two dimming Any kind of dimming method When it uses DC dimming It won't flicker Because there is a light-emitting layer under it Provide light to the screen The light-emitting layer is always on Voltage becomes a little lower The screen becomes dark If you want to brighten the screen Higher voltage It becomes brighter So-called strobe Is the luminous body we see It's not always on But with a fast flashing speed Make you look It seems to be on all the time, but it doesn’t Then the frequency of this flicker Although your eyes looked You can't feel But actually it keeps flickering Will hurt your eyes We know our visual nervous system It's the sensor cells of the eyes that are exposed to light Then through our nerves Pass to the brain And then make a judgment on the light In other words, during transmission Its signal is lossy The flicker our eyes feel May feel it When the brain processes it but cannot feel it So we see it as if we know it It did not flicker But actually its flickering Is flashing on us Flashing in our eyes I just talked about DC dimming How to adjust the brightness up and down Then talk about PWM dimming PWM dimming How does it adjust the brightness Let’s say it’s one second If this screen flashes 60 times Or our lights, some LED lights It has stroboscopic And usually it may be obvious and serious Let’s say one minute, no, one second 60 flashes How to make it look brighter or darker For example, in these 60 times right It has to light up 60 times Then it will be black 60 times If it lights up Longer each time Then this light, this light looks brighter If it lights up for a shorter time It appears darker So this is PWM dimming If you haven't heard what's going on You can watch a show I did before There are more detailed An explanation of the video with pictures We test a device A screen Or a light environment Are you using PWM dimming Is there a stroboscopic method Very simple As long as you turn on the phone's camera Then select the camera to professional mode Then set your shutter speed Adjust to about 1/200 second Then you face the light Don’t have to face the light source For example, in the case of lights You can just shine the light on the place For example, against the wall Or follow the book Then watch If your phone screen Blinking Just explain This lamp you bought It uses PWM dimming The same goes for mobile phones You shoot on the phone The shutter speed is also adjusted to almost 1/200 If you see it, you take this phone Holding this phone for shooting Its screen keeps flickering It means that the screen of the phone being photographed Is used P W M dimming LCD screen mobile phone Is the LCD screen It can choose two dimming methods Most LCD phones now All DC dimming is used But some netizens told me He used a Huawei glory phone The PWM dimming used will also strobe But it’s also an LCD screen So this LCD screen is the worst It uses PWM dimming LCD screen A bit detour Is the worst screen LCD screen with DC dimming Is relatively good It does not flicker On this one To your eyes There won't be any harm But oled screen Just think now A relatively high-end screen Screens commonly used in flagship phones Even Apple has now surrendered to the Oled camp Basically use oled screen It can only be used PWM dimming As for why these flagship machines To use Oled screen I was in the previous episode Also introduced I will put links to these shows Include the link to the article just now In the introduction of this show You can just go and order The advantage of Oled screen is Better picture quality In short, it's like this Of course there are other advantages and disadvantages There is a contrast between them I said in that show But oled screen Only use PWM dimming method It must have strobe Especially when the light is turned down When you watch at night Look when the surrounding environment is dark Its strobe is more serious why Mentioned earlier Because to make an analogy If it flashes 60 times a second How does it turn down the light Just put these 60 times Reduce the time the screen is on It darkens the fiber So it’s light for a short time Long dark Looks like this flickers This flicker will be more obvious to the eyes Then the damage to the eyes Of course it's bigger Very strange Before I did the show To check information A little bit shocked me My website of the American Academy of Ophthalmology Want to check Some comments on strobe Or these experiments by some scientists I didn't find any I mean it is related to the screen Mobile phone electronic screen related Not found American Academy of Ophthalmology Is a very authoritative place Then I check the information twice Check Blu-ray In unison Almost all scientists Basically i think This should be abnormal Because everyone is blooming It’s impossible to say that an industry just came out Everyone said the same thing in unison In terms of Blu-ray Everyone agrees to say so in unison No proof yet Blu-ray of blue-ray screen electronic devices Dangerous to the eyes Even the voice of doubt Basically can't see I think it is already a Something unusual Then when I went to check the strobe Even an article can’t be found I feel even more abnormal But i'm somewhere else Found some Such articles and data Let me read it to everyone 3~70 Hz Means Within a second It flickers less than 70 times Within a second Its screen lights up No more than 100 times There is basically nothing wrong with this passage We all know about LED lights Maybe some people have children at home I will also buy an eye protection lamp What is the meaning of LED light eye protection? It flickers more every second More flashes It will be longer when it lights up For example, you only blink 60 times a second That's this screen It lights up only 60 times Actually there are 60 intervals Then the interval You think he will be a little bit more relatively Then it gives people eyes This hurt, and the flickering feeling Stronger If more flashes The shorter the interval Actually smaller It feels better like It’s always lit up Like a movie We say that the movie is 60 frames It’s better than a 30-frame movie This picture looks smoother In fact, the so-called 60 frames Just one second It displays 60 screens If the movie reaches 120 frames Even now our mobile phones also say What high refresh rate is the frame rate Then the human eye will look more comfortable Flickering of the screen And the light flickers Is also a similar principle The more it is this kind of P W M dimming If the blinking can be adjusted higher It hurts the human eyes less But why this screen Can't adjust that high Because if the adjustment is too high This screen is prone to aging LED screen And if the adjustment is too high Power consumption will be great Your 4000 mAh battery May run out soon Many netizens left messages to tell me They have different feelings with LCD screen phones and oled screen phones More than 90% say Spicy glasses with oled screen LCD is more comfortable Then someone asked me What kind of phone to choose In fact, the LCD screen uses DC dimming at the same time Will be better for the eyes In fact, there are fewer and fewer phones But there will be a new listing on Double 11 soon But I'm not advertising I did not charge any advertising fees I just tell you the news The latest red rice Just Xiaomi Redmi K30s, just the newest Not yet listed It will be listed on Double 11 Extreme Commemorative Edition It uses a high refresh rate LCD This refresh rate is different from the refresh rate of the strobe we talked about Talking about high refresh rate means its frame rate Is the screen for one second It can show 144 frames It looks like when people are watching movies Or when watching the dynamic Will be comfortable when playing games At the same time it is an LCD screen It uses real DC dimming There won't be any flickering In one second It is not a question of how many times it lights up It keeps on No matter if you are one second Still a minute Still an hour As long as you light up this screen It's always on So if you are someone who likes LCD screen phones Just to consider If you change your phone Can consider this one Because I saw what they just sent The configuration above the advertisement Still feel pretty good Including cameras, etc. Including battery A large 5000 mAh battery is used Also very useful All right Talked so much According to the summary of my own practice Because I also use different phone screens Sometimes to read I have done a lot of comparisons Then based on the feedback from netizens Also based on some of my friends Feedback when chatting with me I came to the conclusion that The hazards of strobe First of all, it must be bigger than Blu-ray As mentioned earlier Blu-ray is also inevitable All devices have right But stroboscopic first can be avoided You choose the true DC dimming of LCD There is no such problem I have to add one more point here Sorry Inside the Oled screen and some mobile phones We see that it has a function Called DC dimming function If you want to turn on this function Flickering of its screen It will become less serious But this DC dimming Actually it is a It can be said to be a little bit deceptive It's not illegal to kick the ball anyway right Actually it is not a real DC dimming But analog DC dimming Two words Omitted If it is true, DC dimming oled screen can be used There is no need to enable this function at all right Just have this function in your phone Directly built in Why should it set up such a function Because of its serious strobe Maybe after many people bought it Feel bad But I can’t help but want to buy oled Because the picture is relatively better Especially playing games Its smear Then its distortion rate will be lower And the contrast of the picture will be higher So can't help but buy it But I also feel uncomfortable with stroboscopic eyes So there is such a compromise Analog DC dimming function But once you turn on this feature The performance of mobile phones will be lost For example, its refresh rate The frame rate will decrease And the power consumption of its screen will increase, etc. Like when I introduced the Xiaomi Mi 10 Extreme Commemorative Edition phone Specifically mentioned this point Xiaomi is a bit more honest When you turn on the so-called DC dimming Anti-screen flicker function It will prompt you to say You turn on this feature You can't enjoy it at the same time High refresh rate of 120 frames You can only use 60 frames Half the refresh rate But some mobile phones don’t remind you It just asks are you sure you want to open Just open it It didn't tell you Actually all the same As long as you turn on the analog DC dimming function Screen performance Will compromise Today may be a mess Because there is no manuscript Just talk in a more casual state Recently because of busy So the show has not been updated for a long time I feel a little sorry everyone Actually my show list I have written a long list Next I will do a show I also plan to do it in a more relaxed way On the one hand talk to everyone Healthy topics On the one hand, it is also a training for self-talk it is good Continue to the conclusion Strobe and Blu-ray Which one hurts the eyes? More serious Just talked about so much comparison There are also conclusions from various laboratories From the electronic devices we use Strobe damage to the eyes Is more harmful than blue light And strobe is relative to blue light Easier to avoid If you are troubled by the scattered screen of the Led screen But I don’t want to change to an LCD screen Of course there are ways When you use your phone Try not to adjust the light to the darkest Keep it some light Because we just talked about This way of PWM It is the brighter the brightness The lower the strobe The darker the brightness Usually higher You can also test this For example, take a mobile phone Shoot on your phone The shutter speed is adjusted to about 1/200 Then you adjust the brightness of the phone being photographed You will find When you want to adjust it to the brightest We seem to see that the screen is not flashing Or the flickering is not obvious When it is adjusted to the darkest The screen flickers will be very obvious There are two ways Is in the article just now Methods introduced by ophthalmologists Three 20 principles Every 20 minutes Take your eyes away from the phone or computer screen Look 20 feet away It's an object almost 7 meters away Watch for at least 20 seconds The last method Is to limit and reduce the two or three hours before going to bed Or not to look at our screen This way it can reduce blue light at the same time And strobe damage to the eyes The last "routine" Thanks everyone for watching Hope you all subscribe Hope everyone likes Hope everyone forwards Thank you Our next video Goodbye
