JP2011161663A - Screen printing squeegee and method for manufacturing flat panel display using the same - Google Patents

Abstract

Disclosed is a squeegee that prevents paste dropping from a squeegee at the time of coating even in a wide range of screen printing, improves the yield due to no pattern defect caused by paste dropping, and increases the production efficiency of the screen printing process. And a method of manufacturing a plasma display panel.
In order to solve the above problems, a screen printing plate of the present invention is a squeegee used for printing a paste on a substrate, and has water and oil repellency on the side surface in the traveling direction during printing of the squeegee. The layer is formed, and the layer is not formed in a region in contact with the printing plate of the squeegee. Here, it is desirable that this layer is mainly composed of fluorine.
[Selection] Figure 2

Description

  The present invention relates to a printing plate used in a printing process and a method for producing a flat panel display using the screen printing squeegee.

  For flat panel display (hereinafter referred to as FDP) substrates such as plasma display panels (hereinafter referred to as PDP), display device substrates such as anode substrates of fluorescent display tubes, electronic devices such as thick film wiring substrates and image sensors In the substrate, a film having a desired function, for example, a rib-shaped partition wall, a conductor wiring, a resistor, or the like is provided on the substrate. For forming these films, for example, a screen printing plate on which a predetermined pattern is drawn is used. This is performed using a thick film screen printing method in which a printing ink disposed on a screen is scanned in one direction so as to be applied to a substrate surface which is a printing object.

  In the configuration of the screen printing plate used in the above screen printing method, for example, a screen in which a predetermined pattern is formed on a rectangular frame is pasted in a state where a predetermined tension is applied. And the opening part used as the discharge hole for allowing the paste for printing to pass through is provided in the screen surface so that a desired printing pattern can be formed.

  A specific screen printing method is to install such a screen plate above a printing stage on which a substrate is placed, and apply a printing paste onto the screen by a scraper moving while pressing in the screen surface. . Thus, the printing paste is filled in the opening of the screen. Note that the scraper is composed of a single plate-like blade whose end contacting the screen is linear.

  Next, after the substrate is placed on the printing stage, the screen plate is aligned with the substrate, brought close to a predetermined position, and moved in the screen surface while pressing the rubber squeegee against the screen. The printing paste filled in the opening is transferred onto the substrate. In this way, a printing paste layer is formed on the substrate, and screen printing is performed (for example, Patent Document 1).

JP 2003-249171 A

  In recent years, flat panel displays such as PDPs are required to be further enlarged. On the other hand, in order to increase the efficiency of the manufacturing process, the glass substrate that is the substrate to be printed is so-called multi-sided, and after the batch printing on the base material substrate, the desired panel size is obtained by cleaving. For this reason, along with this, the coating area required in the screen printing method has become wide.

  On the other hand, the scraper and squeegee are mounted on the same operating shaft in the printing device, and when the scraper is applying paste to the screen (this process is called coating), the squeegee is in the same position as the scraper at a position where it does not contact the screen. The structure moving in this direction is the same as before.

  With such a structure, the printing application area becomes wide, and dropping of the paste from the squeegee at the time of coating becomes a problem. That is, the required paste amount increases as the application area becomes wider. Therefore, the paste position that contacts the squeegee during printing is higher. As a result, after the printing with the squeegee is completed, the paste adhered above the squeegee falls to the screen surface during the next coating operation. Moreover, since the coating operation time becomes longer as the application area becomes wider, the chance of the paste falling further increases.

  During coating, the dropped paste is affected at the paste dropping position, and the screen opening is not sufficiently filled with the paste. As a result, when printing from the screen plate to the glass substrate with a squeegee (this process is referred to as “printing”), the paste application onto the substrate becomes insufficient at the paste dropping position.

  For example, in the case of conductor wiring, this defective coating on the substrate is disconnected, causing a defective product and making it impossible to increase the yield.

  In order to prevent the paste from dropping, it is possible to temporarily stop the apparatus before coating. However, the manufacturing tact in the printing process is lengthened, and the production efficiency cannot be increased.

  The present invention has been made for such a problem, and a screen printing method capable of preventing a drop of paste from a squeegee at the time of coating and improving yield and production efficiency even in a wide range of screen printing. I will provide a.

  In order to solve the above problems, the present invention provides a squeegee used for printing a paste on a substrate, wherein a layer having water repellency and oil repellency is formed on a side surface in a traveling direction of the squeegee during printing. The layer is not formed in a region in contact with the printing plate. Here, it is desirable that this layer is mainly composed of fluorine. The FPD manufacturing method of the present invention is an FPD manufacturing method having a step by a screen printing method, and the screen printing step uses the printing squeegee described above. Here, the screen printing process includes a coating step for applying the paste to the screen and a printing step for copying the paste applied to the screen onto the substrate to be printed, and dropping the paste attached to the squeegee before this coating step. Is desirable.

  By practicing the present invention, even in a wide range of screen printing, the paste is prevented from dropping from the squeegee at the time of coating, the yield is improved due to the absence of pattern defects caused by the paste dropping, and the production efficiency of the screen printing process is increased. Has an effect.

1 is a front view of a printing apparatus according to an embodiment of the present invention. Sectional drawing which cuts and shows the same printing apparatus by the AA line Explanatory drawing which shows each step in the printing process in embodiment of this invention Explanatory drawing which shows the squeegee in embodiment of this invention. Explanatory drawing which shows each step in the printing process in a prior art The fragmentary perspective view of PDP in embodiment of this invention

  Hereinafter, a method for producing a screen printing plate and an FPD according to an embodiment of the present invention will be described with reference to FIGS. As for the FPD manufacturing method, a PDP manufacturing method having a printing process will be described as an example.

  First, a method for manufacturing a PDP using the embodiment of the present invention and its structure will be described. For example, as shown in FIG. 6, a PDP used in a thin display device includes a front glass substrate 2 and a rear glass substrate 3 which are two substrates disposed to face each other so as to form a discharge space 1 therebetween. It has. A plurality of display electrode pairs composed of two display electrodes 4 and 5 are arranged on the front glass substrate 2, and a light shielding layer (black stripe) 6 is formed between the display electrode pairs. A dielectric layer 7 is formed so as to cover the display electrodes 4 and 5 and the light shielding layer 6, and a protective layer 8 made of magnesium oxide is formed on the dielectric layer 7. The display electrodes 4 and 5 include a transparent electrode 9 made of indium tin oxide (ITO) or the like and a bus electrode 10 made of silver or the like formed thereon.

  A plurality of address electrodes 11 are formed on the rear glass substrate 3 in a direction orthogonal to the display electrodes 4 and 5, and a base dielectric layer 12 is formed so as to cover the address electrodes 11. A partition wall 13 is formed on the base dielectric layer 12 so as to be positioned between the address electrodes 11, and a phosphor layer 14 is formed on the surface of the base dielectric layer 12 and the side surfaces of the partition wall 13.

  In the discharge space 1, for example, a discharge gas made of a mixed gas of neon and xenon is sealed at a predetermined pressure. The phosphor layer 14 emits light by ultraviolet rays generated when a display discharge is caused between the display electrode 4 and the display electrode 5 constituting the display electrode pair to display a color image.

  Next, a method for manufacturing a PDP will be described. First, the display electrodes 4 and 5 and the light shielding layer 6 are formed on the front glass substrate 2. The bus electrode 10 is formed on the transparent electrode by screen printing. Thereafter, it is baked and solidified at a desired temperature. The light shielding layer 6 is manufactured by a screen printing method using a black paste containing a black pigment.

  Next, a dielectric paste is applied to the front glass substrate 2 by a die coating method or the like so as to cover the display electrodes 4 and 5 and the light shielding layer 6 to form a dielectric paste layer (dielectric glass layer). After the dielectric paste is applied, the surface of the applied dielectric paste is leveled by leaving it to stand for a predetermined time, so that a flat surface is obtained. Thereafter, by firing and solidifying the dielectric paste layer, a dielectric layer 7 covering the display electrodes 4 and 5 and the light shielding layer 6 is formed. The embodiment of the present invention has a single-layer structure in which coating, drying, and baking processes are performed in a lump without repeating these dielectric paste coating processes. The dielectric paste is a paint containing powdery dielectric glass, a binder, and a solvent. Next, a protective layer 8 made of magnesium oxide (MgO) is formed on the dielectric layer 7 by a vacuum deposition method. Through the above steps, predetermined constituent members are formed on the front glass substrate 2 to complete the front plate.

  On the other hand, the back plate is formed as follows. First, the structure for the address electrode 11 is formed by a method of screen printing a paste containing silver (Ag) material on the rear glass substrate 3 or a method of forming a metal film on the entire surface and then patterning using a photolithography method. An address electrode 11 is formed by forming a material layer to be an object and firing it at a desired temperature. Next, a dielectric paste is applied to the back glass substrate 3 on which the address electrodes 11 are formed by a die coating method so as to cover the address electrodes 11 to form a dielectric paste layer. Thereafter, the base dielectric layer 12 is formed by firing the dielectric paste layer. The dielectric paste is a paint containing powdery dielectric glass, a binder, and a solvent.

  Next, a partition wall forming paste including a partition wall material is applied onto the base dielectric layer 12 and patterned into a predetermined shape to form a partition wall material layer, and then fired to form the partition walls 13. Here, as a method of patterning the partition wall paste applied on the base dielectric layer 12, a photolithography method or a sand blast method can be used. Next, the phosphor layer 14 is formed by applying and baking a phosphor paste containing a phosphor material on the base dielectric layer 12 between the adjacent barrier ribs 13 and on the side surfaces of the barrier ribs 13. Through the above steps, predetermined constituent members are formed on the back glass substrate 3 to complete the back plate.

  In this way, the front plate and the back plate provided with predetermined constituent members are arranged to face each other so that the display electrodes 4 and 5 and the address electrodes 11 are orthogonal to each other, and the periphery thereof is sealed with a glass frit, and the discharge space. A PDP is completed by enclosing a discharge gas containing Ne, Xe, etc. in 1.

  In the embodiment of the present invention, when the light shielding layer 6, the dielectric layer 7, or the bus electrode 10 is formed on the front glass substrate 2, or the address electrode 11, the base dielectric layer 12, and the partition wall 13 are formed on the rear glass substrate 3. Alternatively, a screen printing process for forming the phosphor layer 14 and a printing squeegee used at that time are provided.

  Next, the screen printing apparatus used in the embodiment of the present invention will be described. FIG. 1 shows a front view of a printing apparatus used when applying a printing paste on a substrate, and FIG. 2 shows a cross-sectional view taken along the line AA. The screen printing apparatus includes a printing stage 18 for placing the substrate 21, a scraper 19 for applying a printing paste on the screen 16 of the screen plate 17, and a printing paste applied on the screen 16. And a squeegee 22 for transferring onto the substrate 21. Here, in the figure, an X axis, a Y axis, and a Z axis that are orthogonal to each other are set, and the Z axis is a vertical direction.

  The screen plate 17 is formed by stretching a screen 16 in which fine wires made of stainless steel, nylon, polyester, or the like are formed in a mesh shape, with high tension in the plate frame 15, and is fixed to the screen holding table 24. .

  The printing stage 18 is disposed below the screen plate 17. The printing stage 18 can be moved in the Z direction so that the distance between the substrate 21 placed on the printing stage 18 and the screen plate 17 can be changed. Four auxiliary substrates 25 are provided on the printing stage 18 so as to be in contact with the respective sides of the substrate 21. The four auxiliary substrates 25 are arranged in at least one of the X direction and the Y direction. It is movable. Of the four auxiliary substrates 25, for example, two auxiliary substrates 25 may be fixed on the printing stage 18. The printing stage 18 is provided with a substrate positioning means (not shown) for positioning the substrate 21 at a predetermined position and a suction device (not shown) for sucking and fixing the substrate 21 to the printing stage 18. Yes.

  The scraper 19 is, for example, a stainless steel blade, and the squeegee 22 is, for example, rubber. The tip of the scraper 19 and the squeegee 22 are linear. The scraper 19 and the squeegee 22 are respectively attached to a scraper holding member 26 and a squeegee holding member 27 made of, for example, an air cylinder so that the scraper 19 and the squeegee 22 can move up and down. The scraper holding member 26 and the squeegee holding member 27 are attached to a support member 28 disposed above the scraper holding member 26 and the support member 28 is movably held by guide rails 29 disposed on both sides thereof. A predetermined driving device for moving the support member 28 in the Y direction is provided. That is, the scraper 19 and the squeegee 22 can be simultaneously moved in the Y direction and separately moved in the Z direction.

  In the embodiment of the present invention, a layer having water repellency or oil repellency (hereinafter referred to as a coating layer 30) is formed on a part of the side surface in the printing direction of the squeegee 22. The coating layer 30 is preferably composed mainly of fluorine or Teflon (registered trademark). And this coating layer 30 is not formed in the area | region where the squeegee 22 and the screen plate mentioned below contact | connect.

  Next, a series of operations in the screen printing process in the embodiment of the present invention will be described with reference to FIG.

  First, after supplying the printing paste 20 along one side of the screen 16 provided on the screen plate 17, the scraper 19 is disposed (FIG. 3A).

  Subsequently, the printing paste 20 is applied onto the screen 16 by moving the scraper 19 in the direction of the arrow (Y direction) while pressing the tip of the scraper 19 against the screen 16. Fill the opening (this is the coating step). At this time, the squeegee 22 is moved in the same manner as the scraper 19 while being retracted upward so as not to interfere with the scraper 19 (FIG. 3B). In the embodiment of the present invention, the dropping of the paste from the squeegee 22 to the application area is prevented in this coating step. This will be described in detail later.

  Next, after placing the substrate 21 on the printing stage 18 and positioning the substrate 21 with substrate positioning pins (not shown) or the like, the auxiliary substrate 25 is placed around the substrate 21. Then, the substrate 21 is brought close to a predetermined position below the screen plate 17, and the screen plate 17 and the substrate 21 are relatively aligned (FIG. 3C). Note that a series of operations for placing the auxiliary substrate 25 may be performed after the substrate 21 is placed and positioned on the printing stage 18 while the printing paste 20 is applied on the screen 16.

  Thereafter, the printing paste 20 filled in the opening of the screen 16 is transferred onto the substrate 21 by moving the squeegee 22 in the direction of the arrow (Y direction) while pressing the squeegee 22 against the screen 16. A paste layer 23 is formed (this is a printing step). At this time, the scraper 19 is moved in the same manner as the squeegee 22 while being retracted upward so as not to interfere with the squeegee 22 (FIG. 3D).

  Next, the squeegee 22 in the embodiment of the present invention and the coating layer 30 for preventing the paste from dropping from the squeegee 22 in the coating step will be described. FIG. 4 shows a squeegee according to an embodiment of the present invention, where FIG. 4A is a cross-sectional view and FIG. 4B is a plan view. As described above, the squeegee 22 is fixed to the apparatus and has the coating layer 30 on a part of the side surface in the printing direction. The coating layer 30 is mainly composed of fluorine or Teflon (registered trademark), and the repelling of the paste is good.

  Since the squeegee 22 having the coating layer 30 on a part of the side surface in the traveling direction of the printing step of the squeegee 22 is used, the paste adhered to the coating layer 30 in the printing step (FIG. 3D) is applied to the squeegee 22. Compared to the case where there is no coating layer, it falls to the lower part of the squeegee 22 earlier. Therefore, at the end of the printing step, the amount of paste adhering to the upper part of the squeegee 22 is small, and the paste is removed sufficiently from the squeegee (for example, the operation of intermittently contacting the squeegee 22 to the screen edge outside the coating area). Can be excluded. The coating layer 30 may be a component having good water and oil repellency with respect to the paste other than fluorine.

  In the embodiment of the present invention, the coating layer 30 is not formed in the region where the squeegee 22 is in contact with the screen 16. When the coating layer is formed even in the region where the squeegee is in contact with the screen, the coating layer is worn and peeled off during the printing step, and impurities remain in the coating region, thereby deteriorating the quality of the coating film. The embodiment of the present invention adopts such a form to prevent this phenomenon.

  On the other hand, FIG. 5 shows each step of the printing process in the prior art. In the same figure, the same number is shown about the site | part similar to embodiment of this invention.

  Thus, in the prior art, the coating layer 30 is not provided on the squeegee 122. For this reason, as described above, the paste (FIG. 5 (d)) adhering to the upper part of the squeegee 122 in the printing step does not sufficiently fall to the lower part of the squeegee 122 at the end of the printing step, and during the coating step (FIG. )) Falls onto the screen 16.

  At the place where the paste has fallen, the scraper 119 impedes the filling of the screen 16 with the paste, resulting in an area where the paste is not sufficiently filled with the screen. As a result, in the printing step, there is a region where the paste is not sufficiently applied to the substrate (a region where the paste has been removed), resulting in a printing failure.

  Recently, in order to significantly improve the production capacity of PDPs, a so-called multi-sided process has been adopted in which a single large substrate is used to produce a plurality of single substrates when forming the front plate or the back plate. Yes. The embodiment of the present invention is desirably employed in a printing process in this multi-chamfering process. For example, even if the printing distance and the paste amount increase, by using the squeegee 22 having the coating layer 30, the same effects as the sheet-fed printing with a small printing distance and paste amount can be obtained at the end of the printing step. Can do.

  Thus, when the PDP is manufactured, the screen printing process and the squeegee according to the embodiment of the present invention are used to prevent the paste from dropping from the squeegee at the time of coating even in a wide range of screen printing. Efficiency can be increased.

  In the embodiment of the present invention, the technique for forming the coating layer on the squeegee has been described. However, the effect of the present invention can be further expected by forming the coating layer on the scraper in the same form as the squeegee.

  As is clear from the above description, by implementing the present invention, the yield and manufacturing efficiency can be increased, and it is very useful in industries such as flat panel displays whose screens are increasing.

2 Front glass substrate 3 Back glass substrate 16 Screen 17 Screen plate 18 Printing stage 19 Scraper 20 Printing paste 21 Substrate 22 Squeegee 30 Coating layer

Claims (4)

A squeegee used for printing a paste on a substrate, wherein a layer having water repellency and oil repellency is formed on a side surface in a traveling direction of the squeegee, and the layer is in a region in contact with the printing plate of the squeegee A squeegee for printing, characterized in that it is not formed. The squeegee for printing according to claim 1, wherein the layer is mainly composed of fluorine. The flat panel display manufacturing method which has the process by a screen printing method WHEREIN: In the said screen printing process, the printing squeegee of Claim 1 is used, The manufacturing method of the flat panel display characterized by the above-mentioned. The screen printing process includes a coating step of applying a paste to the screen and a printing step of copying the paste applied to the screen onto a substrate to be printed, and dropping the paste attached to the squeegee before the coating step The manufacturing method of the flat panel display of Claim 3.

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