The embedded industrial touchscreen monitor has a high demand for its performance due to its application in the harsh environments, such as high and low temperature, full of dust, water or oil. Especially, it is a great challenge for the embedded industrial touch displays in the high and low temperature environment. Therefore, it is necessary for the embedded industrial touch displays have excellent performance when running in high and wide temperature applications.
So how does embedded industrial touchscreen monitor achieve reliable performance in wide temperature environment?
1. Wide temperature mode and working principle
(1) Mode 1: Adopting low temperature heating
There are two ways of low temperature heating: point by point heating and whole surface heating. The overall power consumption of such a display will increase 4-6 times. For example, the power consumption of 15 inch LCD at room temperature (22 ℃) is 20W, and the power consumption at low temperature (- 40 ℃) is 90-120W. This heating mode may cause some problems such as difficult to recovery or the LCD flowing out during the process of long-term use.
(2) Mode 2: Improve the brightness of LCD
Through the development of a special high-voltage strip (which can generate 2000v-3000v starting voltage), the backlight tube is turned on at low temperature (- 40 ℃), the liquid crystal heats up because of the huge heat generated by the backlight tube. This way achieves two goals, that is to solve the problem of low-temperature operation of the liquid crystal, and also solve the problem of visibility in the sunlight. This way is referred to as the brightening way.
Disadvantages of mode 1 and mode 2:
① Both of them increase many accessories and reduce the reliability.
② Assembly production is more troublesome, easy to cause defective, defective rate is higher.
③ The ability of the device to resist shock and vibration is reduced.
④ In the aging test, it is found that the aging speed is very fast at 50 ℃, and the acceleration is rising, especially in the way of brightening, the service life is only one tenth of normal.
(3) Mode 3: New liquid crystal high and low temperature application technology, the product work normally at low temperature conditions without heating or brightening.
The basic principle is as follows: the liquid crystal does not freeze or change its state at low temperature (- 40 ℃), otherwise, neither heating mode nor brightening mode can work, so we think of using software to correct the drift of its electrical characteristics. Try to trigger the LCD at low temperature. This requires adjusting the driving timing of the liquid crystal and so on. Through a large number of experimental research and extensive application, this technology has been very mature. No matter how the ambient temperature changes, the normal operation of the liquid crystal can be guaranteed by widening the trigger timing and matching the corresponding driver.