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Technical parameters of LCD

LCD fonts

How small is the font size of the wide-screen LCD? The size of the pixels and fonts corresponds. If the pixels are small, the text will become smaller. Wide-screen panels generally have a much higher resolution than flat-screen panels of the same size, so they have much smaller fonts and poor visual acuity. How small is the wide-screen font? Pixel height (proportional to font size): 15'plain screen 0.298mm 15.4'(width) 0.259mm 14.1' plain screen 0.280mm 14.1'(width) 0.237mm 13' (width) 0.219mm 12'plain screen 0.238mm 12' (width), let alone that font is small to abnormal...
Thus, the popular 14-inch wide screen character is too small, even smaller than the 12-inch screen.

Technical parameters of liquid crystal display

Visible area

The size indicated by LCD is the same screen range that can be used in practice. For example, a 15.1-inch LCD is about equal to the visual range of a 17-inch CRT screen.

Viewing angle

The viewing angle of LCD is symmetrical from left to right, but not from top to bottom. For example, when the incident light from the backlight passes through the polarizer, liquid crystal and alignment film, the output light has a specific directional characteristic, that is to say, most of the light emitted from the screen has a vertical direction. If we look at a completely white picture from a very oblique angle, we may see black or color distortion. Generally speaking, the upper and lower angles are less than or equal to the left and right angles. If the viewing angle is about 80 degrees, it means that the screen image can be clearly seen when the position begins at 80 degrees of the screen normal. However, due to the different range of vision, if you do not stand in the best visual angle, the color and brightness you see will be erroneous. In the market, most LCDs have a viewing angle of about 160 degrees. Some first-line brands, such as Asus, Samsung, LG, AOC and so on, have a horizontal visual angle of 170 degrees. With the development of science and technology, some manufacturers have developed a variety of wide-angle technologies, trying to improve the perspective characteristics of LCD, such as: IPS (In Plane Switching), MVA (Multidomain Vertical Alignment), TN + FILM. These technologies can increase the viewing angle of LCD to 178 degrees at most, which is very close to the traditional CRT display.

Dot distance

We often ask about the dot distance of LCD, but most people don't know how to get this value. Now let's know how to get it. For example, the visible area of a 14-inch LCD is 285.7 mm * 214.3 mm, and its maximum resolution is 1024 * 768. Then the point distance is equal to: visible width / horizontal pixels (or visible height / vertical pixels), i.e. 285.7 mm / 1024 = 0.279 mm (or 214.3 mm / 768 = 0.279 mm).

Color degree

LCD is of course important for color performance. We know that any color in nature consists of three basic colors: red, green and blue. LCD panel is composed of 1024 x 768 pixels. Each independent pixel color is controlled by three basic colors: red, green and blue (R, G, B). Most manufacturers produce liquid crystal displays, each basic color (R, G, B) reaches 6 bits, that is 64 representations, then each independent pixel has 64 *64 *64=262144 colors. Many manufacturers also use the so-called FRC (Frame Rate Control) technology to simulate the full-color picture, that is, each basic color (R, G, B) can reach 8 bits, that is, 256 expressiveness, then each independent pixel has up to 256 *256 *256 = 16777216 colors.

Contrast value

Contrast value is defined as the ratio of the maximum brightness value (all white) divided by the minimum brightness value (all black). The contrast of CRT monitors is usually as high as 500:1, so it is easy to show a true full-black picture on CRT monitors. But it is not easy for LCD. The backlight consisting of a cold cathode ray tube is difficult to switch on and off quickly, so the backlight is always in the state of light. In order to get a full black picture, the LCD module must completely block the light coming from the backlight, but in terms of physical characteristics, these components can not fully meet such requirements, so there will always be some leakage. Generally speaking, the acceptable contrast value for human eyes is about 250:1.

Luminance value

The maximum brightness of LCD is usually determined by the cold cathode ray tube (backlight). The brightness value is generally between 200 and 250 cd/m2. LCD displays have a slightly lower brightness, which makes the screen darker. Through years of experience, the brightness of liquid crystal displays is generally 250 cd/m2 in the market today, and those over 24 inches are slightly higher, but they are basically maintained between 300 and 400 cd/m2. Although they can achieve higher brightness technically, this does not mean that the higher the brightness, the better, because too high brightness of the display may cause eye injury.

Response time

Response time refers to the speed at which each pixel of the LCD reacts to the input signal. Of course, the smaller the value, the better. If the response time is too long, it is possible to make the LCD display have the feeling of tail shadow dragging when displaying dynamic images. Generally, the response time of LCD is between 5 and 10 ms. In the first-line brands such as Asus, Samsung and LG, the response time is generally less than 5 ms, which basically avoids the tail shadow dragging problem.

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