One, foreword

With the rapid development of science and technology, the information revolution brings us to an electronic age, the development of electronic and communications equipment, has represented by liquid crystal display module of flat-panel display technology rapidly into homes, as a result, liquid crystal display module, if there is a light-leaking unhealthy phenomenon became inspection flat-panel display device one of the key factors, this article through to analysis the root cause of the liquid crystal display module light-leaking unhealthy phenomenon, caused by liquid crystal display module are determined by using tests light-leaking adverse factors, and treatment Suggestions are put forward.

Second, the liquid crystal display module light-leaking definition

LCD is widely used in the information age of the plane display device, it has the characteristics of low energy consumption, appearance of thin, light weight, by the liquid crystal display, connectors, IC, electronic circuit board and back board and other structures and liquid crystal display module is the main equipment flat display. TV and LCD panel light-leaking phenomena occur, this exactly is what reason is caused, is it normal? Light-leaking what is, in fact light-leaking with panel structure has very big relations, first is mainly composed of liquid crystal display (TFT LCD) and backlight (BLU) and flexible circuit board (FPC) of the three most liquid crystal display module (TFT LCM) in the general case light-leaking is a very normal phenomenon, because light-leaking will not affect the brightness of the LCD TV and LCD itself, more will not affect the response speed of LCD TV and LCD monitor and service life, the only affect is the whole panel display effect. When the brightness of the backlight LED lamp mouth is significantly higher than in other regions in the position of light spot or bright column is known as:.

Three, the reason for liquid crystal display module light-leaking due to

The causes of liquid crystal display module light-leaking

According to the statistical analysis of some products, LCD TV and LCD light-leaking undesirable reasons, of which 93% is caused by bad glare, therefore, can be concluded that light-leaking bad key problem is to solve the problem of glare.

2 causes of glare

Produce glare is one of the reasons for the backlight of liquid crystal display module, the LED lamp light is direct injection, rather than according to the normal situation through guide plate evenly spread out, at the same time, another is that the guide plate to make the effect not beautiful also can produce a similar situation. From the above two cases for segmentation, can bring seven reasons.

(1) LED lights on the guide plate thick

When the thickness of the LED lights more than guide plate, then beyond part of light will be out from the top of the direct radiation of light guide plate, was the light of these without uniform emission of light guide plate to form the glare. By adopting the spiral micrometer implement measure of guide plate and the LED lamp, respectively, on the measured average statistics compare the average of the measured data of the statistical data shows that there are significant differences: leds to thicker than the guide plate.

(2) the FPC impreaaion nip force is greater than the FPC double-sided adhesive force

When FPC impreaaion nip force is too large will replace the LCD, causing dislocation with LED lights in the light of light guide plate can not be normal after uniform emission of light guide plate and glare. For FPC impreaaion nip strength, however, there is no quantitative method test impreaaion nip force, so the double-sided adhesive coefficient and viscose area are the narrow to verify whether it can cause glare. Under different adhesive area by comparing the rate of glare, confirm to reflex ability than FPC FPC assumption of double-sided adhesive force.

(3) employee extrusion die set

By observing the operation gimmick than production line staff found that there is a staff in the machining process of extrusion die set happens by accident, which, through carries on the squeezing pressure on the module test, found that pinch pressure will make the LED and LCD contact, when come into contact with the LED and LCD are squeezed, LED at the top of the double-sided adhesive will be LED stick and then move. So for employee extrusion die set and cause glare hypothesis is true.

(4) exists between LCD and LED gap

When the liquid crystal display module by pressure makes the gap exists between the LCD and LED, double-sided adhesive will stick on the LED drive it happen and migration, thus light-leaking phenomenon. In order to confirm the size of the clearance fit, we use the 0.1 mm plug gauge clearance for the different thickness of the test, the final conclusion is: 0.1 + 0.06 + 0.02 vinyl combination can into space, and use the vinyl combination of 0.15 + 0.06 can't into space, because black rubber itself is the biggest thickness: 0.06 mm, so the size of the gap is: 0.12 mm, note: LCD and LED gap exists between the glare of hypothesis.

(5) the Windows from the LED light glare of short distance

With backlit D2 design length of 2.9 mm model, for example, due to the operation staff can lead to effective D2 deviation, we of D2 length is 3.1 mm and 2.9 mm two different conditions of glare rate compares the detection, check its differences in different circumstances, the test results: under the condition of the two, with the increase of D2 distance, the glare of the defective rate is on the decline. Therefore, the small Windows from the LED lamp light distance is also one of the elements of glare.

(6) branches of light guide plate and the possibility of sawtooth caused bad glare of light guide plate

Bad points of light guide plate and light guide saw bad need IQC inspection, the length of the D2 is 3.1 mm and 2.9 mm respectively two length of 20 pieces of guide plate is used to detect the defective rate, the result is: the effect of light guide plate can accept 10, effect of light guide plate also have ten piece that is not acceptable. Again by two inspectors to extract inspection of 500 pieces of guide plate respectively, are found no adverse of light guide plate, so that bad points of light guide plate and light guide saw bad is not a major factor in the production of glare.