CN109036171B

CN109036171B - Liquid crystal screen signal switching belt sealing method

Info

Publication number: CN109036171B
Application number: CN201810749875.XA
Authority: CN
Inventors: 袁烨; 陈彬; 刘儒锋; 陈韬; 王晗
Original assignee: AVIC Huadong Photoelectric Co Ltd
Current assignee: AVIC Huadong Photoelectric Co Ltd
Priority date: 2018-07-10
Filing date: 2018-07-10
Publication date: 2021-01-26
Anticipated expiration: 2038-07-10
Also published as: CN109036171A

Abstract

The invention discloses a sealing method for a liquid crystal display signal transfer belt, which comprises the following steps: step 1, connecting the FPC and the signal switching belt through an abnormal conductive adhesive film in a hot-pressing manner; step 2, coating sealant on the hot-pressing position of the FPC and the signal transfer belt, and pasting an anti-static adhesive tape; and 3, after the sealant is cured, coating the sealant on the periphery of the FPC and the signal transfer belt, and sticking the anti-static adhesive tape again. The liquid crystal screen signal transfer belt sealing method solves the problems of screen splash, screen blackness, screen whiteness and the like caused by comprehensive environmental stress.

Description

Liquid crystal screen signal switching belt sealing method

Technical Field

The invention relates to a sealing method of a liquid crystal display signal transfer belt.

Background

The liquid crystal display has the highest application requirement on airplanes, is influenced by outdoor ambient light, has higher brightness requirement (generally more than 800cd/m2) for meeting the requirement of strong light visibility, and is generally designed to be about 400cd/m2 for civil display brightness. The liquid crystal screen is a passive luminous display medium, and the high-brightness display of the liquid crystal display is realized mainly by improving the brightness of a backlight source. The design of the backlight is a key factor for realizing the high brightness of the liquid crystal display.

The backlight is divided into a bottom backlight and a side backlight according to the position in the display, the two backlights respectively have advantages and disadvantages, the area of the bottom backlight is large, more LED light sources can be designed, and higher brightness is realized. However, in order to avoid the occurrence of the lamp shadow display defect, the light mixing space of the liquid crystal display needs to be increased, and the thickness of the liquid crystal display is increased. The light sources of the side backlight can only be arranged around the product, the space area is small, more LED light sources cannot be designed, and the brightness is relatively low. This has the advantage that a thinner liquid crystal display can be made. Therefore, military-use lcd displays typically use a bottom-backlight design, while civilian-use lcd displays typically use a side-backlight design. Because the shelf liquid crystal display is usually suitable for a side backlight system, the length design of the FPC is short, if the shelf liquid crystal display is applied to a system with a bottom backlight design, a liquid crystal display drive board needs to be installed at the bottom of a backlight, the distance between the liquid crystal display FPC and the drive board is long, and an electrical interface of the liquid crystal display FPC cannot be in butt joint with a plug-in unit of the drive board. Only by extending the liquid crystal screen FPC can the liquid crystal screen be electrically communicated with its drive board.

At present, the extension of the liquid crystal screen FPC is realized by connecting the liquid crystal screen FPC with a customized extension signal switching belt through an abnormal-square conductive adhesive film (ACF). The ACF consists of colloid and conductive particles, and is easily corroded by water vapor in the environment, so that the contact resistance is increased, and the signal display is influenced. Military liquid crystal displays must meet higher environmental reliability requirements, such as high temperature and high humidity environments, and even some more severe comprehensive environmental stresses, such as temperature and humidity vibration tests. The comprehensive environmental stress test can better reflect the actual use environment of the product and has practical significance. From the development trend analysis of the test, the reliability test of the military liquid crystal display is more and more inclined to simulate the real use environment for carrying out multi-stress comprehensive investigation. The comprehensive environmental stress test indeed exposes more fatal functional defects of the product, such as the phenomena of screen faults, black screen faults, white screen faults and the like. The faults all occur on a signal channel, and the analysis on the fault products shows that the liquid crystal screen FPC adopts a signal transfer belt extension process, the faults all occur at the hot-pressing connection position of the liquid crystal screen FPC and the signal transfer belt, and the ACF is corroded by water vapor.

Sealant is coated on the contact position of the front panel of the liquid crystal display and the surface of the liquid crystal screen, and moisture can not enter from the front end of the module; matching gaps are formed among the periphery and the tail of the module, the panel, the screen frame, the backlight frame and the rear cover plate, the gaps are small, the sealant cannot permeate, and water vapor can enter. In the process of carrying out comprehensive environmental stress test on a product, the product is arranged in a tool or a host machine shell, a narrow closed space is formed between the tool or the host machine shell and the product under the action of comprehensive environmental stress of temperature and moisture, once water vapor enters, the water vapor is condensed into water drops in the cooling process, and the narrow gap is not easy to discharge; along with the increase of the number of test cycles, the water in the machine shell is further increased and gradually permeates into the product through gaps among structural members of the product to form accumulated water; at this moment, under the action of the vibration stress, water can enter the product more easily, more accumulated water is formed, and the humidity environment in which the product is arranged is far greater than the test humidity condition. The signal switching department of hot pressing extension is usually sealed through the sticky tape, after steam soaked for a long time, make the sticky tape gum lose viscidity, sticky tape substrate and gum separation, thereby lose the sealing effect, steam soaks LCD screen FPC and signal switching area hookup location through the sticky tape edge gradually, contain conductive impurity in the steam, there is more ponding in signal switching area and FPC crimping point, signal contact such as the Clock (CLK) signal that leads to the LCD screen and LCD screen driving voltage (VGH, VGL, VCOM) is not good or there is less resistance phenomenon with adjacent pin, the clock is lost or driving voltage is not enough, thereby lead to LCD to appear the flower screen, black screen and white screen trouble.

Aiming at the reliability problem of the current liquid crystal screen signal switching process, the problem can be solved by an antistatic adhesive tape and a sealant. After the liquid crystal display FPC and the signal transfer belt are hot-pressed, sealant is coated on the seams of the upper surface and the lower surface of the FPC and the signal transfer belt around the hot-pressing position, and then the hot-pressing position is wrapped by the anti-static adhesive tape and the sealant is covered. To further increase the sealing reliability, the FPC and signal relay tape can continue to be sealed integrally using the same method. The sealant can bear the test of comprehensive environmental stress after being cured, and the requirement of high reliability of military liquid crystal displays is met.

Through the analysis, the invention provides a liquid crystal display signal transfer tape sealing process.

Disclosure of Invention

The invention aims to provide a liquid crystal screen signal transfer belt sealing method which solves the problems of screen splash, black screen, white screen and the like caused by comprehensive environmental stress.

In order to achieve the above object, the present invention provides a sealing method for a signal transfer tape of a liquid crystal display, including:

step 1, connecting the FPC and the signal switching belt through an abnormal conductive adhesive film in a hot-pressing manner;

step 2, coating sealant on the hot-pressing position of the FPC and the signal transfer belt, and pasting an anti-static adhesive tape;

and 3, after the sealant is cured, coating the sealant on the periphery of the FPC and the signal transfer belt, and sticking the anti-static adhesive tape again.

Preferably, in step 1, the FPC and the signal transfer tape are electrically connected by hot pressing through an irregular square conductive adhesive film.

Preferably, in step 3, after the sealant is cured, the method of coating the sealant around the FPC and the signal transfer tape and applying the antistatic adhesive tape again includes:

and coating the sealant on the periphery of the FPC and the signal transfer belt, and coating the sealant on the upper surface and the lower surface of the FPC and the signal transfer belt.

According to the technical scheme, the liquid crystal display screen using the signal transfer process can be guaranteed to withstand the multi-stress comprehensive environment test, and the environment reliability of the liquid crystal display screen signals is improved. The comprehensive environment stress reliability is high, the structure is simple, the implementation is convenient, and the practical range is wide.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram illustrating a specific structure of a signal transfer tape sealing structure of a liquid crystal display panel according to the present invention;

fig. 2 is an enlarged structural view illustrating a signal transfer tape sealing structure of a liquid crystal panel according to the present invention.

Description of the reference numerals

1 liquid crystal display 2 FPC

3 signal switching belt 4 antistatic adhesive tape

5 anisotropic conductive adhesive film 6 sealant

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

In the present invention, unless otherwise specified, the directional words included in the terms such as "up, down, left, right" and the like merely represent the directions of the terms in a conventional use state or are colloquially known by those skilled in the art, and should not be construed as limiting the terms.

The invention provides a sealing method for a liquid crystal display signal transfer belt, which comprises the following steps:

In one embodiment of the present invention, in step 1, the FPC and the signal transfer tape are electrically connected by hot-pressing an irregular-shaped conductive adhesive film.

Through the embodiment, the electrical connection can be realized, and the anisotropic conductive adhesive film can be hot-pressed on the FPC and the signal transfer tape.

In a specific embodiment of the present invention, in step 3, after the sealant is cured, the method of coating the sealant around the FPC and the signal transfer tape and attaching the antistatic adhesive tape again includes:

By the embodiment, the FPC and the signal transfer belt can be sealed, and complete sealing of the FPC and the signal transfer belt is ensured.

In the invention, the sealed liquid crystal screen signal transfer belt can bear the reliability test of a multi-stress comprehensive environment, and the environmental reliability of the liquid crystal screen signal is improved.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims

1. A liquid crystal screen signal transfer belt sealing method is characterized by comprising the following steps:

step 3, after the sealant is cured, coating the sealant on the periphery of the FPC and the signal transfer belt, and sticking an anti-static adhesive tape again; wherein the content of the first and second substances,

in step 3, after the sealant is cured, the sealant is coated around the FPC and the signal transfer tape, and the method of attaching the antistatic adhesive tape again includes:

2. The method for sealing a signal transfer tape of a liquid crystal display panel according to claim 1, wherein in step 1, the FPC and the signal transfer tape are electrically connected by hot pressing with an irregular square conductive adhesive film.