What does screen refresh rate mean?

The screen refresh rate means the number of times the electron beam scans the screen image repeatedly, that is, the number of times the screen is refreshed per second; the higher the screen refresh rate, the better the stability of the displayed image. , the calculation unit of screen refresh rate is "Hz". When using a refresh frequency above 70Hz, flickering can be basically eliminated.

#The operating environment of this tutorial: IOS15 system, iphone13 pro mobile phone.

What does the screen refresh rate mean?

The refresh rate refers to the number of times the electron beam repeatedly scans the image on the screen. Simply put, the refresh rate is the number of times the screen is refreshed per second. The higher the refresh rate, the better the stability of the displayed image (picture). The refresh rate will directly determine its price, but since the refresh rate and resolution are mutually restrictive, only a monitor with a high refresh rate at high resolution can be called excellent performance.

Note that although its calculation unit and vertical scanning frequency are both Hz, these are two completely different concepts. The 75Hz screen refresh rate is the most basic standard set by VESA for flicker-free. The 75Hz here should be a standard that can be achieved in all display modes.

For traditional monitors, the lower the refresh frequency, the more severe the image flicker and jitter, and the faster the eyes will tire. Sometimes it can cause sore eyes, dizziness and other symptoms. Because 60Hz is close to the refresh frequency of fluorescent lamps, an uncomfortable stroboscopic effect will occur when the display is at a refresh rate of 60Hz. When using a refresh frequency above 70Hz, flickering can be basically eliminated. Therefore, a refresh rate of 70Hz is the minimum requirement for stable operation of the monitor.

Among mobile phone screen refresh rates, the OLED screen refresh rate has a better experience than the LCD screen refresh rate, is smoother, and saves power. LCD high refresh rates will have a smearing effect, which affects the experience.

You can understand it this way, the refresh rate is the number of times the screen is refreshed per second. When watching a movie, what we see is actually a still picture, just like a slide show. Why do we feel the picture It is moving because human eyes have a visual retention effect. The impression left in the brain of the previous picture has not disappeared, and the next picture follows immediately, and the difference between the two pictures is very small. The action needs to be displayed with many sub-pictures, so that we feel that the picture is moving. The replacement of each picture is refreshing. Assuming that an action is completed by 20 pictures, we will look a bit like a cartoon, and If this action is increased to 30 pictures, it will look much more natural. This is the refresh rate.

Extended knowledge: The impact of refresh rate

Hardware

The most important thing that affects refresh rate The factor is the bandwidth of the monitor. Nowadays, the bandwidth of a 17-inch color display is generally around 100, which can fully support 85Hz. The larger the screen, the greater the bandwidth. The 19-inch one is around 200, the 21-inch one is around 300, and the same brand and size Color display, the higher the bandwidth, the more expensive the price. Secondly, the refresh rate is affected by the graphics card. The graphics card also has available refresh rates and resolutions, but as far as the refresh rate is concerned, this can be completely ignored now, because this is mainly for the older generation of graphics cards, even the antique TNT2 graphics cards. , can also support 1024*768 resolution to achieve 85Hz effect, 1024*768 is the standard resolution of 17-inch CRT monitor. Therefore, the main thing that affects the refresh rate is the bandwidth of the display.

Software

The biggest impact on the refresh rate is the resolution of the screen. For example, it is also a 17-inch color display with a bandwidth of 108. If the resolution is adjusted to 1024*768, the maximum can be 85Hz, increase it to 1280*1024, the maximum can only reach 70Hz, decrease it to 800*600, but it can reach 100Hz. The higher the resolution, the lower the refresh rate when the bandwidth remains unchanged. To maintain a high refresh rate, the only way is to use a high bandwidth, so the bandwidth of large-screen displays is very high.

Line frequency

The horizontal frequency refers to the number of times the electron gun in the image tube scans from left to right on the screen per second. The unit is Hz. The field frequency refers to the repeated drawing per second. The number of times the picture is displayed, the unit is Hz, the horizontal frequency and the vertical frequency are the basic electrical properties of a monitor.

Bandwidth

Bandwidth represents a comprehensive indicator of the monitor and is also an important indicator to measure the quality of a monitor. Bandwidth refers to the number of images scanned per second, that is to say, the sum of the number of frequency points displayed on each scanning line per unit time, the unit is Hz. There is a certain calculation method for the bandwidth size. Everyone is choosing For a monitor, the bandwidth can be calculated based on some parameters, or some parameters can be calculated based on the bandwidth. When the monitor's refresh rate increases a little, its bandwidth will increase a lot.

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