LCD and backlight unit brightness automatic constant circuit thereof

Abstract

The invention relates to a liquid crystal display (LCD) and a backlight unit brightness automatic constant circuit thereof. The backlight unit brightness automatic constant circuit comprises a brightness setting circuit, a brightness detection circuit, a comparison circuit and a brightness control circuit, wherein the first input end of the comparison circuit is connected with the brightness detection circuit; the second input end of the comparison circuit is connected with the brightness setting circuit; and the output end of the comparison circuit is connected with the brightness control circuit which is connected with a backlight unit. The LCD can rapidly reach the set brightness after startup, maintains the constant brightness during the working process and effectively ensures the display picture quality for a long time because of the adopted backlight unit brightness automatic constant circuit which is also provided with a temperature detection and comprehension circuit for overcoming the temperature drift influence of an electronic circuit. Accordingly, the invention can better satisfy the user needs and be beneficial to the improvement of the working efficiency and quality of users.

Description

technical field [0001] The invention relates to a liquid crystal display, in particular to a liquid crystal display with a backlight unit brightness automatic constant circuit. Background technique [0002] The backlight unit of the liquid crystal display includes light-emitting tubes, such as cold cathode fluorescent tubes (CCFLs), light-emitting diodes (LEDs), and the like. Usually, the brightness adjustment of the display screen is to manually input the brightness setting signal, and increase or decrease the power supply current of the light-emitting tube through the control circuit, so that the display screen can reach the required brightness. However, since the luminous characteristics of the luminous tube are variable and unstable, the luminance will vary with temperature and usage time, and manual adjustment is required after the luminance changes. This kind of performance defect has little impact on general applications, but it may be intolerable for applications in...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a backlight unit brightness automatic constant circuit for the defect that the liquid crystal display in the prior art cannot quickly reach the set brightness after starting up and the brightness changes after a long working time

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