A kind of method that reduces the electrocorrosion of liquid crystal display module
Technical field
The present invention relates to a kind of working method of LCD, relate in particular to the working method of the liquid crystal display module in a kind of LCD.
Background technology
Monochrome liquid crystal display module [LCM-Liquid Crystal Display Module]; Usually fixed on the surface that is positioned at low substrate of LCD device 2 with chip 3 by direct nation; Be on the step surface 21 shown in Figure 1, and realize that with conductive lead wire 5 mode that is electrically connected encapsulates, be i.e. COG-Chip on Glass packaged type; Chip 3 is connected with FPC (being called for short FPC) 7, specifically sees figures.1.and.2.Aforementioned conductive lead wire 5 is generally formed by metal indium-stannic oxide [ITO].The COG packaged type can reduce the volume of whole liquid crystal display device module greatly; And be easy to produce in enormous quantities; Be particularly useful for the LCD [LCD-Liquid Crystal Display] that consumer electronics product is used; Like portable type electronic products such as mobile phone, PDA, and will be the main connected mode of chip and LCD from now on.
The liquid crystal display device module of above-mentioned mode of production gained and LCD in use the phenomenon that displaying contents lacks stroke occurs through regular meeting, make the defective products rate improve, or reliability of products descend.
Existing applicant finds that the immediate cause that above-mentioned phenomenon occurs is: tin indium oxide conductive lead wire 5 often has corrosion phenomenon and takes place in encapsulation and use, causes tin indium oxide conductive lead wire broken string; Thereby the defective products rate occurring improves or reliability decrease; Aforementioned defective products rate is generally: about 1%~5%, and along with the product passing of service time, bad phenomenon can not stop to occur; Bad ratio also can be increasingly high, and therefore the many factories in the industry lose huge.
Further analyze; This corrosion is actually electrocorrosion; As the liquid crystal display device module and the lcd products of aforementioned technology encapsulation are done hot and humid experiment: will show that normal LCM powers up driving, the chip 3 tin indium oxide conductive lead wire on every side that is positioned at glass surface does not apply any glue-line, does not promptly do any protection; After LCM energising shows, under 60 ℃, 90%RH environmental baseline, do the environmental reliability test.Find in the test phenomenon that opens circuit to have occurred showing at experience a period of time sample.The product that this demonstration is opened circuit is examined under a microscope; Find that the phenomenon of galvanic corrosion in various degree appears in the tin indium oxide conductive lead wire that is connected with chip around the chip 3; And idol has the phenomenon of broken string to occur; Fig. 3 is the conductive lead wire galvanic corrosion picture of examining under a microscope, and Fig. 4 is the electrocorrosion synoptic diagram, lead-in wire fracture 9 on partial oxidation indium tin conductive lead wire 5, occurs.
The mechanism of production of above-mentioned electrocorrosion phenomenon is: the tin indium oxide conductive lead wire belongs to the conductive lead wire that Sn mixes, and Sn and oxygen room have good electric conductivity as alms giver's N type oxide semiconductor; The distance between centers of tracks that each conductive lead wire of tin indium oxide is adjacent is very little, usually between 0.01mm~0.03mm; And liquid crystal display device module of producing with the COG packaged type and lcd products are in process of production; Because the tin indium oxide conductive lead wire around the chip is to expose in the external world; Be easy to suffer the pollution of ion; In addition, the relative humidity on tin indium oxide conductive lead wire surface is generally also non-constant, and the surface is planar water steam easily.And liquid crystal display device module and lcd products are in procedure for displaying; Can there be voltage difference on two adjacent tin indium oxide conductive lead wires; If have moisture content and ion to exist between the conductive lead wire, will under effect of electric field, produce faint electric current; Thereby make tin indium oxide conductive lead wire generation redox reaction, so just cause the generation of electrocorrosion phenomenon especially easily.
In the technology of the existing liquid crystal display device module of producing with the COG packaged type,, has only the report that uses silica gel though use glue is also arranged; Because the silica gel permeability rate is high; It is just kept apart dust and product, can not water vapor and product be kept apart, thereby not reach the protection to the special anti-electrocorrosion of the tin indium oxide conductive lead wire of chip and chip periphery; When therefore producing in batches, the quality of product is difficult to control.
Summary of the invention
The purpose of this invention is to provide a kind of method that reduces the electrocorrosion of liquid crystal display module, be intended to solve in production of existing liquid crystal display module or the use, electrocorrosion takes place easily, cause product the defective that opens circuit often to occur showing.
The present invention is achieved in that a kind of method that reduces the electrocorrosion of liquid crystal display module, specifically comprises the following steps:
1.1 chip nation is fixed on the ledge surface that is positioned at the formation of LCD upper and lower base plate;
It is characterized in that:
1.2 on said chip and the surface of tin indium oxide conductive lead wire on every side thereof, use ultraviolet curing glue, make a coating film layer;
1.3 in 5~120 minutes time, the said rete that is coated with is solidified;
1.4 the liquid crystal display module of encapsulation gained.
Further, for improving the effect of anti-electrocorrosion, in step 1.2, the water-intake rate of the ultraviolet curing glue of being selected for use should be less than 2.5%, the specific insulation after solidifying should be greater than 3E+15 ohmcm, hardness less than 100 Shao Shi D; In step 1.3, make after the said curing to be coated with that thicknesses of layers is controlled at be in 0.1~3mm millimeter.
The method of reduction liquid crystal display module provided by the present invention electrocorrosion; Because the step that utilizes liquid crystal display module upper and lower base plate to form, chip after nation is fixed and the surface of tin indium oxide conductive lead wire on every side thereof have made a coating film layer immediately targetedly separately; Reduce the entering chance of water vapour and ion; Especially select for use set time short, compactness is good, the ultraviolet curing glue that water absorptivity is low; The chance that electrocorrosion takes place the liquid crystal display module be can effectively reduce in encapsulation, use, thereby the yield rate and the reliability of the liquid crystal display module of producing in batches improved.
Description of drawings
Fig. 1 is existing liquid crystal display device module vertical section structure synoptic diagram;
Fig. 2 is existing liquid crystal display device module cross-sectional structure synoptic diagram;
Fig. 3 is existing liquid crystal display device module tin indium oxide conductive lead wire electrocorrosion displaing micro picture;
Fig. 4 is existing liquid crystal display device module tin indium oxide conductive lead wire electrocorrosion synoptic diagram;
Fig. 5 is a liquid crystal display device module vertical section structure synoptic diagram of the present invention;
Fig. 6 is the method for making technological process sketch of liquid crystal display device module according to the invention.
Embodiment
In order to make the object of the invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with accompanying drawing and embodiment.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
Referring to Fig. 5 and Fig. 6, the method for reduction liquid crystal display module provided by the invention electrocorrosion specifically comprises the following steps:
At first chip 3 nations are fixed on the ledge surface 21 that is positioned at LCD upper substrate 1, infrabasal plate 2 formation; Chip and the surface of tin indium oxide conductive lead wire on every side thereof after again nation being decided; Use set time short; Compactness is good, the ultraviolet curing glue that water absorptivity is low, such as: the A-202 type ultraviolet curing glue that can directly select Japanese ponding company for use; Make a coating film layer 6 separately; This is coated with rete and is coated in chip and tin indium oxide conductive lead wire on every side thereof surface, avoids or reduces the chance that impurity such as steam, ion get in the liquid crystal display module processed, the LCD use, and the qualities such as reliability of manufactured goods are provided;
The principle of work of ultraviolet curing glue is: the light trigger in the glue (photosensitizer) absorbs ultraviolet under ultraviolet irradiation after; Produce living radical or kation; Trigger monomer polymerization, molecule crosslinked and connect Zhi Huaxue reaction, it is solid-state that bonding agent is converted into by liquid state in the several seconds kind.The present invention makes full use of the feature performance benefit of ultraviolet curing glue: promptly quick solidifying, pollution-free, with the bonding strength height of glass, good weatherability, for a long time use not flavescence, compactness is good, water permeability is low.
Aforementioned making is coated with the process of rete and also should tries one's best fast, generally should the said rete that is coated with solidified in 5~120 minutes time; And then row is with the liquid crystal display module of common packaging technology encapsulation gained.
In the practice; Like the water-intake rate of the ultraviolet curing glue selected for use specific insulation less than 2.5%, after solidifying greater than 3E+15 ohmcm, hardness during less than 100 Shao Shi D; In the batch process of liquid crystal display device module of producing with the COG packaged type and lcd products; The bad ratio of product can reduce significantly, and fraction defective can be controlled in 0.01%; After the curing to be coated with that thicknesses of layers generally is controlled at be in 0.1~3 millimeter, product reliability in use also is able to obvious raising.