Resolution concept analysis

- Mar 31, 2020-

Resolution is an important prerequisite for ensuring the clarity of a color display. The dot pitch of the display is one of the foundations of high resolution. The dot pitch of large screen color displays is generally 0.28, 0.26, 0.25. On the other hand, high resolution refers to the maximum pixel points that the display can achieve in horizontal and vertical display. Generally, there are 320 × 240, 640 × 480, 1024 × 768, 1280 × 1024, etc. Good large screen color display Can usually reach a resolution of 1600 × 1280. Higher resolution means not only higher definition, but also more content can be displayed in the same display area. For example, only one page of content can be displayed at 640 × 480 resolution, and two pages can be displayed at the same time at 1600 × 1280 resolution.

Resolution is a parameter that measures the amount of data in a bitmap image. It is usually expressed as pixels per inch (ppi) and dots per inch (dpi). The more data it contains, the longer the graphics file will be and the richer the details will be. But larger files require more computer resources, more memory, more hard disk space, and so on. If the image contains insufficient data (lower graphics resolution), it will appear quite rough, especially when the image is enlarged to a larger size for viewing. So during image creation, we have to decide the correct resolution based on the end use of the image. The trick here is to ensure that the image contains enough data to meet the needs of the final output. At the same time, it should be appropriate to minimize the use of some computer resources.

Generally, "resolution" is expressed as the number of pixels in each direction, such as 640X480. In some cases it can also be expressed as "pixels per inch" (ppi) and the length and width of the graphic. For example, 72ppi, and 8x6 inches.

Ppi and dpi are often mixed. From a technical point of view, "pixels" (P) only exist in the field of computer display, and "dot" (d) only appear in the field of printing or printing.

Resolution is directly related to the pixels of the image. Let's calculate, a picture with a resolution of 640 x 480 will have a resolution of 307,200 pixels, which is what we often say is 300,000 pixels, and a picture with a resolution of 1600 x 1200. Its pixels are 2 million. In this way, we know that the two numbers of resolution represent the unit of the points occupied by the picture in the length and width. The aspect ratio of a digital picture is usually 4: 3. LCD liquid crystal display and traditional CRT display, resolution is one of the important parameters. The resolution supported by traditional CRT displays is more flexible, and the pixel pitch of LCD has been fixed, so the supported display modes are not as many as CRT. The best resolution of LCD, also called maximum resolution, is the best resolution at which an LCD monitor can display the best image.

The best resolution of a 15-inch LCD is 1024 × 768, and the best resolution of 17 to 19 inches is usually 1280 × 1024. A larger size has a larger optimal resolution.

When the LCD display presents a lower-resolution display mode, there are two ways to display it. The first is centered display. For example, when displaying an SVGA 800 × 600 screen on an XGA1024 × 768 screen, only 800 × 600 pixels in the center of the screen are displayed, and other pixels that are not displayed remain dark. This method is more Use less. The other is called extended display: when displaying a picture below the optimal resolution, each pixel is expanded to display adjacent pixels by a differential algorithm, so that the entire picture is filled. This also makes the picture lose its original sharpness and true colors.

Because the maximum resolution of liquid crystal displays of the same size is usually the same, the price of LCDs of the same size generally has nothing to do with the resolution.

WVGA: 800 * 480

QVGA: 320 * 240

VGA: 640 * 480

HVGA: 480 * 320

QVGA stands for "Quarter VGA". As the name implies, it is a quarter of the size of VGA, which means that the resolution on the LCD screen is 240 × 320 pixels. QVGA supports screen rotation, and corresponding programs can be developed to display screen positions rotated 90 °, 180 °, 270 °. Published by HandEra, mostly used for handheld / mobile devices.

It needs to be said that some media are mistaken for QVGA screens to be the same as LCD materials such as TFT and TFD. QVGA screens are more common in some mobile phones in Japan. Most of the smartphone screens using the Microsoft Pocket PC operating system are 320 × 240 pixel QVGA screens. 

The so-called QVGA LCD technology is a liquid crystal output method with a resolution of 240 × 320 on the LCD screen. This resolution has nothing to do with the size of the screen itself. For example, if the 2.1-inch LCD screen can display 240 × 320 resolution images, it is called “QVGA 2.1-inch LCD screen”; if the 3.8-inch LCD screen can display 240 × 320 images, it is called “QVGA 3.8-inch” "LCD screen", although the above two cases have the same resolution, but the actual visual effects are different due to different sizes. Generally speaking, a small screen will naturally be more delicate. 

HVGA is half of VGA (640 * 480), and the resolution is (480 * 320), (3: 2 aspect ratio). It is used in a variety of PDA devices, first of which is the Sony Clie PEG-NR70 in 2002, one of WVGA digital product screen materials, another form of VGA, higher resolution than VGA, alias: Wide VGA, , Its resolution is 800 × 480 pixels, which is an enlarged VGA (640 × 480) resolution. Used in PDAs and mobile phones, etc., because the width of many web pages is 800, the WVGA screen will be more suitable for browsing web pages, which can be said to be a major trend in the resolution of handheld devices in the future.