Patent Application
20130061877
The present application claims priority over Japanese Patent Application JP2011-198329 filed on Sep. 12, 2011, the contents of which are hereby incorporated into this application by reference.
(1) Field of the Invention
The present invention relates to a cleaning method, and in particular to a cleaning method for cleaning the surface of the members of a liquid crystal display panel after being disassembled by blowing dry ice pellets against them using dry air.
(2) Description of the Related Art
In recent years, hybrid products made of a front panel and a liquid crystal display panel pasted together and hybrid products made of a front panel, a liquid crystal display panel and a touch panel pasted together have been mass produced.
Ultraviolet ray curing resins (hereinafter referred to as UV resins) are mainly used to paste parts to general hybrid products. In the case where these hybrid products are found to be defective as a result of inspection by turning them on or by checking their appearance, the members to which a UV ray adheres are discarded instead of being repaired because UV resins are hardened films and are very difficult to remove.
In the case where a hybrid product made of a front panel and a liquid crystal display panel pasted together is found to be defective as a result of inspection by turning it on or checking its appearance, for example, only the liquid crystal display panel is reused, and presently, the upper polarizing plate of the liquid crystal display panel and the front panel are discarded without being repaired because it is very difficult to remove the UV resins. In addition, the backlight and the upper frame of the liquid crystal display panel deform at the time of disassembly, and therefore are discarded instead of being repaired.
Patent Document 1: Japanese Unexamined Patent Publication 2004-008995
As described above, though UV resins are used to paste members to hybrid products, it is difficult to remove the UV resins, and therefore, almost all the members to which a UV resin adheres are discarded.
In addition, the UV resins that have been adhered to the outside of liquid crystal display panels to be repaired are manually cleaned by a worker who uses a cloth or a cotton swab soaked with a solvent from which fiber particles are not easily generated and cleaned carefully so as not to break the product.
Therefore, such problems arise that the amount of discarded members is large and it takes time to clean the parts to which a UV resin has been adhered.
The present invention is provided in order to solve the above-described problems with the prior art, and an object of the present invention is to provide a cleaning method using dry ice pellets, which makes it possible to efficiently peel off UV resins.
The above-described and other objects and novel features of the present invention will be clarified from the descriptions of the present specification and the accompanying drawings.
Typical features of the invention disclosed in the present specification are briefly outlined as follows.
The present invention provides a cleaning method for cleaning an object to be cleaned that is fixed to a fixture, which is characterized in that dry air is used to blow dry ice pellets against a surface of the above-described object to be cleaned so that the surface of the above-described object is cleaned.
In addition, according to the present invention, the above-described dry air has a dew point from −60° C. to −80° C.
Furthermore, according to the present invention, a nozzle for jetting the above-described dry air and the above-described dry ice pellets against the surface of the above-described object to be cleaned is provided, and the distance between the above-described nozzle and the surface of the above-described object to be cleaned is 5 mm to 70 mm.
Moreover, according to the present invention, the above-described nozzle has a circular or elliptical shape in a cross-section, and the above-described nozzle is angled at 30° to 80° relative to the surface of the above-described object to be cleaned.
In addition, according to the present invention, a fixing means for fixing the above-described object to be cleaned to the above-described fixture; and a heating means for heating the surface of the above-described object to be cleaned to a temperature of 20° C. to 80° C. are provided. More preferably, a heating means for heating the surface to a temperature of 40° C. to 80° C. is provided.
Furthermore, according to the present invention, the above-described dry ice pellets have a diameter of 1 mm to 3 mm and a length of 1 mm to 5 mm, more preferably, the length is 1 mm to 3 mm.
Moreover, according to the present invention, the above-described object to be cleaned is any of an upper polarizing plate of a liquid crystal display panel, a touch panel or a front window of a product after being disassembled.
The effects gained by the typical features of the invention disclosed in the present specification are briefly described as follows.
The cleaning method using dry ice pellets according to the present invention makes it possible to efficiently peel off a UV resin.
In the following, the embodiments of the present invention are described in detail in reference to the drawings.
Here, throughout all the drawings for illustrating the embodiments, the same symbols are attached to the components having the same functions, and the descriptions thereof are not repeated. In addition, the following embodiments do not limit the interpretations of the scope of the present invention.
[Conventional Liquid Crystal Display Device]
In
The liquid crystal display panel (LCD) has a first substrate (SUB1, glass substrate, for example), a second substrate (SUB2, glass substrate, for example) and a liquid crystal layer (not shown) sandwiched between the first substrate (SUB1) and the second substrate (SUB2). In addition, a lower polarizing plate (POL1) is formed on the first substrate (SUB1) (on the backlight (BL) side), and an upper polarizing plate (POL2) is formed on the second substrate (SUB2) (on the viewer's side).
In
Here, scan lines (also referred to as gate lines), counter electrodes (also referred to as common electrodes), an interlayer insulating film, video lines (also referred to as source lines or drain lines), thin film transistors, pixel electrodes and an alignment film are formed on the first substrate (SUB1) on the liquid crystal layer side in this order.
A light blocking film, red, green and blue color filters, a flattening film and an alignment film are formed on the second substrate (SUB2) on the liquid crystal layer side in this order.
The liquid crystal display panel (LCD) is formed by layering the first substrate (SUB1), on which pixel electrodes, thin film transistors and the like are formed, and the second substrate (SUB2), on which color filters and the like are formed, on top of each other with a predetermined distance in between, pasting the two substrates together using a sealing material provided in the peripheral portion of the two substrates in frame form, injecting liquid crystal inside the sealing material between the two substrates through an opening provided in the sealing material so that the liquid crystal is sealed therein, and pasting polarizing plates outside the two substrates.
Here, the counter electrodes can be applied to a TN (twisted nematic) type and a VA (vertically aligned) type liquid crystal display devices. In the case of a TN type or VA type liquid crystal display panel, the counter electrodes are provided on the second substrate side. In the case of an IPS type, they are provided on the first substrate side.
The present invention does not relate to the internal structure of liquid crystal panels, and therefore, a detailed description of the internal structure of the liquid crystal panel is omitted. Furthermore, the present invention can be applied to a liquid crystal panel having any structure.
[Problems with Prior Art]
In the case where a hybrid product made of a front panel (FW) and a liquid crystal display panel (LCD) pasted together as in
Furthermore, the UV resins (UVP) that have been adhered to the outside of liquid crystal display panels (LCD) to be repaired are manually cleaned by a worker who uses a cloth or a cotton swab soaked with a solvent from which fiber particles are not easily generated and cleaned carefully so as not to break the product.
Therefore, such problems arise that the amount of discarded members is large and it takes time to clean the parts of the liquid crystal display panel (LCD) to be repaired to which a UV resin (UVP) has been adhered.
The present embodiment is characterized in that, in the case where the hybrid product made of a front panel (FW) and a liquid crystal display panel (LCD) pasted together as in
In
The dry ice blasting apparatus 100 adjusts the airflow volume of the dry air and outputs the dry ice pellets and the dry air to a pressurized hose 104 so that a nozzle 110 blows the dry ice pellets and the dry air against an object to be cleaned (liquid crystal display panel (LCD) in
The removed UV resin (UVR) is suctioned through an air duct 105 together with the air that is suctioned through an air duct pipe 107 and is captured by a filter 106.
First, the nozzle 110 provided at the tip of the pressurized hose 104 of the dry ice blasting apparatus 100 accelerates dry ice pellets (DPR) by means of dry air so that the dry ice pellets (DPR) are jetted against the surface of an object (BUH) (see
As a result, the dry ice pellets (DPR) enter into the UV resin (UVP) that has been adhered to the surface of the object (BUH) (see
The hardness of the dry ice pellets (DPR) is two or less according to Mohs scale, and therefore, the dry ice pellets (DPR) spread laterally when colliding with the surface of the object (BUH) so as to enter between the UV resin (UVP) and the object (BUH) and quickly evaporate so that the volume thereof expands. This change in the volume spreads the space in between so that the UV resin (UVP) is blown off (see
The dry ice pellets (DPR) that have been jetted from the nozzle 110 are instantly sublimated into carbon dioxide, and therefore, there is no residue (see FIG. 4(d)).
In
In
In
As described above, in
In the following, the conditions for the cleaning method using dry ice pellets according to the embodiments of the present invention are described.
In the case where the shape of the nozzle 110 in a cross-section is circular as shown in
As for the distance between the nozzle 110 and the object to be cleaned, 5 mm to 70 mm is optimal. In the case where the distance between the nozzle 110 and the object is 5 mm or less, there is a risk that the surface of the object may be scratched or the pattern printed on the surface of the object may be peeled off. Furthermore, there are such defects that dew may be formed due to the lowering of the temperature on the surface of the object or the efficiency in removing the UV resin may be poor because the area from which the UV resin is removed using dry ice pellets (DPR) is small.
Moreover, in the case where the distance between the nozzle 110 and the object is 70 mm or more, the impact of the collision of dry ice pellets (DPR) is weak, and thus, there is such a defect that the efficiency in removing the UV resin is low.
It is necessary to determine an appropriate angle of the nozzle 110 depending on the location and the area of the extraneous matter to be removed. The angle of the nozzle 110 that is perpendicular)(90°) to the surface of the object is defective because the dry ice pellets (DPR) that have been jetted from the nozzle 110 and collided with the surface of the object may be diffused. In the case where the angle of the nozzle 110 is small, the angle at which the dry ice pellets (DPR) make contact with the surface of the object is small, which is defective because the efficiency in removing the UV resin is low. Therefore, as for the angle of the nozzle 110, 30° to 80° is optimal.
It is necessary to keep the temperature on the surface of the object at 20° C. to 80° C. at the lowest so that no dew is formed on the surface of the subject (the surface from which the UV resin (UVP) is to be removed in
Therefore, a heating mechanism 121 is provided to the fixture 120 in
Dry air having a dew point of −60° C. to −80° C. is optimal. The temperature at which dry ice sublimates is −79° C., and therefore, water included in the dry air forms dew when the dry ice pellets (DPR) are jetted from the nozzle 110 in the case where the dew point is high. The thus-formed dew lowers the cleaning efficiency.
As for the diameter of the dry ice pellets (DPR), 1 mm to 3 mm is appropriate. In the case where the diameter of the dry ice pellets (DPR) is 1 mm or less, the surface area of the dry ice pellets (DPR) is small, which is defective because the efficiency in removing the UV resin is low.
In the case where the diameter of the dry ice pellets (DPR) is 3 mm or more, the surface area of the dry ice pellets (DPR) is large, which makes the area of contact at the time of blasting large, and thus, the UV resin tends to be removed inconsistently.
It is preferable for the length of the dry ice pellets (DPR) to be 1 mm to 5 mm, and it is more preferable for it to be 1 mm to 3 mm.
Though in the above the cleaning method using dry ice pellets according to the present invention is described by citing an embodiment where it is applied to the method for repairing a hybrid product made of a front panel (FW) and a liquid crystal display panel (LCD) pasted together, the present invention is not limited to this and can be applied to a method for repairing a hybrid product made of a front panel (FW), a touch panel (T/P) and a liquid crystal display panel (LCD) pasted together.
In this case, it is necessary to remove the UV resin (UVP) remaining on the two surfaces of the touch panel (T/P) in addition to the UV resin (UVP) remaining on the upper polarizing plate (POL2) of the liquid crystal display panel (LCD) shown in
The cleaning method using dry ice pellets according to the present invention is also applicable to the cleaning of the following parts of a liquid crystal display panel (LCD).
Furthermore, the cleaning method using dry ice pellets according to the present invention can be applied to the following cleaning in the manufacturing process for a liquid crystal display panel (LCD).
Though the invention made by the present inventor is concretely described on the basis of the above embodiments, the present invention is not limited to the above-described embodiments, and various modifications are naturally possible as long as the gist of the invention is not deviated from.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-198329 | Sep 2011 | JP | national |
