The role of negative pressure in LCD screens

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The role of negative pressure in LCD screens [Copy link]

In daily work, we occasionally encounter customer feedback: the LCD screen does not display or displays very light after it is turned on. The impact of voltage on this problem is often ignored by us.

LCD display requires two voltages for power supply, one is logic voltage and the other is negative voltage. Different sizes of LCD screens require different voltages. Generally, the larger the screen, the greater the operating voltage required.

Let's take the 320240 dot matrix LCD screen as an example. The driving voltage of this type of LCD screen is generally above 10V. If you want to increase the duty cycle of a high-driving LCD screen , you must increase the driving voltage of the LCD . In daily life, our module power supply voltage is generally 3V or 5V , which is far from meeting the driving voltage of the LCD . In this case, we need to use a negative voltage and the power supply voltage to form a larger potential difference to drive the liquid crystal molecules to achieve the working conditions we need.

Therefore, if the driving voltage of the LCD screen is higher than the working voltage and there is no negative voltage, there will be no display. If the negative voltage is not adjusted to meet the working conditions, the display will be very dark or very light.

This content is originally created by EEWORLD forum user Rohm LCD Technology Station . If you want to reprint or use it for commercial purposes, you must obtain the author's consent and indicate the source

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Use a negative voltage and the supply voltage to form a larger potential difference

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