The display effect of LCD is usually determined by the following parameters.
1 Contrast. Contrast is actually the ratio of the maximum brightness value divided by the minimum brightness value, which represents the color gradation that the LCD can display. Nowadays, touch all-in-one devices are more and more used in professional fields such as education and training, and users' demands for contrast are increasing. The "Multimedia Teaching Environment Engineering Construction Standards" drafted by the Ministry of Education and participated in the drafting by the Shiwo brand pointed out that the LCD contrast ratio is generally from 1000: 1 to 1600: 1. There is also a concept here, dynamic contrast, which refers to the contrast value measured under certain circumstances, which is generally 3 times the contrast. At present, the dynamic contrast ratio of screens of well-known brands such as Shiwo can generally reach more than 4000: 1, which fully meets the needs of most users. Some products claim to increase the dynamic contrast to tens of thousands to one hundred to one hundred to one by adjusting the brightness of the backlight, which is not very meaningful in practice.
2 brightness. The liquid crystal itself does not emit light, so the maximum brightness of the LCD usually depends on the backlight. At present, there are mainly two types of backlight sources: cold cathode ray tubes and LED diodes. For LCDs, the first-level screens can reach 350cd / m2 or more, which fully complies with the 300cd / m2 effective brightness in the "Code". If the brightness is too low, the screen will feel dark. It should be noted that in actual use, the brightness is not as high as possible, the display brightness is too high, prone to visual fatigue after prolonged use.
3 Response time. Response time refers to the speed at which LCD pixels respond to input signals. The response time is too long, and there will be a sense of drag when displaying dynamic images. The response time of a general LCD display is between 20 and 30ms. With the continuous improvement of technology, the response time of the display screens of brands such as Shiwo has been controlled at about 5.5ms, which improves this disadvantage of traditional touch-integrated devices.
Of course, there are other important factors that determine the display effect of the touch all-in-one.
LCD board drive technology is a very critical item. In operation, the liquid crystal drive uses an electric field to change the state of the liquid crystal, control how much light penetrates, and there is a negative correlation between voltage and how much light penetrates. Therefore, the liquid crystal drive plays a role in controlling the brightness of light by the level of the voltage applied to the liquid crystal. No matter how high the technical parameters of the LCD screen are, it still has to rely on the LCD board driver to achieve a perfect display. In this technology, Chinese companies have done very well. The world's largest independent design company for LCD panel driver is the CVT Group from China.
Another key technology is the signal transmission method. The same display screen adopts HDMI full digital high-definition transmission, which can greatly reduce the damage and distortion of the video signal during transmission. Compared with VGA analog signal transmission, there will be very large differences in display color and dynamic effect. At present, domestic brands such as Shiwo can transmit signals via HDMI.
In summary, the display effect of the LCD in the touch-control all-in-one depends not only on its own technical parameters, but also on the driving of the liquid crystal board and the signal transmission technology. Only products that can reach a higher level in these two aspects can provide users with the best presentation effects and viewing experience.
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