TWI479964B - A printing method, a printing apparatus, and a method of manufacturing a solar cell using the same - Google Patents

Description

Printing method, printing device, and manufacturing method of solar cell using the same

The present invention relates to a printing method, a printing apparatus, and a method of manufacturing a solar cell using the same.

A typical crystalline silicon solar cell has an anti-reflection film formed on a photoelectric conversion portion having a pn junction formed thereon, and has a structure of a comb-shaped surface electrode and a full-surface back electrode. The surface electrode and the back electrode are formed by printing a metal paste and sintering. Since the irradiation light is shielded by the surface electrode, the area covered by the surface electrode cannot be used for power generation (so-called shadow loss).

Reducing the electrode area can reduce the shadow loss, but the resistance of the electrode increases, resulting in a loss of resistance, resulting in a decrease in the fill factor (FF). Therefore, simply reducing the electrode area does not improve the conversion efficiency, and when the electrode area is reduced, it is necessary to take measures to reduce the resistance loss such as thickening the electrode (forming an aspect ratio electrode) in the reduced portion.

A multiple printing technique of screen printing is disclosed as an electrode formation for obtaining a high aspect ratio (Patent Document 1). However, since the oozing of the edge in the screen printing described above makes it impossible to form a sharp electrode, there is a gravure offset printing which can reduce the bleeding of the edge portion. Multiple printing techniques are disclosed (Patent Document 2).

Further, as a measure for reducing the electric resistance loss, a technique of forming a surface electrode by bonding a metal wire to a light-transmitting conductive film by a conductive adhesive is disclosed (Patent Document 3).

[First technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 11-103084

[Patent Document 2] JP-A-2007-44974

[Patent Document 3] Patent No. 4459271

These methods have the advantage of being able to manufacture a high conversion efficiency solar cell because of multiple printings, but it is difficult to position and it is difficult to describe a technique of high productivity.

The present invention has been made in view of the above problems, and an object thereof is to improve a transfer rate of a printed matter in a printing method using a gravure. Further, the object of the present invention is to obtain an electrode having a high aspect ratio and a solar cell using the same by a method of high productivity.

In order to achieve the object of solving the above problems, the present invention is characterized in that the first filling step includes filling a first printing material in a concave portion of the plate, the plate being a pattern having a surface formed by a groove-like concave portion; a step of drying the filled first printing material; a second filling step, filling the filling The recessed portion of the first printing material is filled with the second printing material; and the transferring step is performed by mechanically pressing the first and second printing materials from the recessed portion before drying of the second printing material The printing of the first and second printing materials is performed on the printing surface of the printed matter, and printing is performed on the printing surface of the printed matter.

According to the present invention, since the paste is thickened in the groove-like recess of the shape to be printed, it is not necessary to perform positioning as in a plurality of printings, and the electrode having a high aspect ratio can be easily printed.

11‧‧ version

12‧‧‧ recess

13‧‧‧Scraper

13a‧‧‧1st scraper

13b‧‧‧2nd scraper

14‧‧‧

14a‧‧‧1st paste

14b‧‧‧2nd paste

15‧‧‧Air Supply Department

16‧‧‧Supply Department

20‧‧‧Solar battery substrate

20S‧‧‧Printing surface

23‧‧‧Back electrode

24B‧‧‧Table auxiliary electrode

24G‧‧‧ grid electrode

24RB‧‧‧ back auxiliary electrode

30‧‧‧Extrusion Department

31‧‧‧Air supply space

33‧‧‧Porous Department

34‧‧‧Supply hole

41‧‧ version

42a‧‧‧1st recess

42b‧‧‧2nd recess

43‧‧‧Retractable film

44‧‧‧Attraction hole

45‧‧‧Confined space

46a‧‧‧Pressure valve

46b‧‧‧Attraction valve

47‧‧‧ Pressurized tube

48‧‧‧ suction tube

61‧‧ version

62‧‧‧Table auxiliary electrode

63‧‧‧Grid electrode section

64‧‧‧ ribs

71‧‧‧ version

72‧‧‧ recess

74‧‧‧Supply hole

81‧‧ version

82‧‧‧ grooved recess

83‧‧‧Shield

84‧‧‧ Air

91‧‧ version

92‧‧‧Piston

Fig. 1-1 is a cross-sectional view showing the steps of the printing principle of the printing method according to the first embodiment of the printing method of the present invention.

Fig. 1-2 is a cross-sectional view showing the steps of the printing principle of the printing method according to the first embodiment of the printing method of the present invention.

Fig. 1-3 is a cross-sectional view showing the steps of the printing principle of the printing method according to the first embodiment of the printing method of the present invention.

Fig. 1-4 is a cross-sectional view showing the steps of the printing principle of the printing method according to the first embodiment of the printing method of the present invention.

Fig. 1-5 is a cross-sectional view showing the steps of the printing principle of the printing method according to the first embodiment of the printing method of the present invention.

Fig. 2 is a schematic view showing a printing apparatus which performs the printing method of the first embodiment.

[Fig. 3-1] Fig. 3-1 shows the printing of the second embodiment of the printing method of the present invention. A cross-sectional view of the steps of the printing principle of the brush method.

Fig. 3-2 is a cross-sectional view showing the steps of the printing principle of the printing method according to the second embodiment of the printing method of the present invention.

3-3] Fig. 3-3 is a cross-sectional view showing the steps of the printing principle of the printing method according to the second embodiment of the printing method of the present invention.

Fig. 3-4 is a cross-sectional view showing the steps of the printing principle of the printing method according to the second embodiment of the printing method of the present invention.

Fig. 4 is a schematic view showing a printing apparatus of the printing method of the second embodiment.

Fig. 5-1 is a cross-sectional view showing the steps of the printing principle of the printing method according to the third embodiment of the printing method of the present invention.

Fig. 5-2 is a cross-sectional view showing the steps of the printing principle of the printing method according to the third embodiment of the printing method of the present invention.

Fig. 5-3 is a cross-sectional view showing the steps of the printing principle of the printing method according to the third embodiment of the printing method of the present invention.

Fig. 5-4 is a cross-sectional view showing the steps of the printing principle of the printing method according to the third embodiment of the printing method of the present invention.

Fig. 6 is a schematic view showing a printing apparatus of the printing method of the third embodiment.

Fig. 7-1 is an enlarged explanatory view showing an important part of the printing procedure of the third embodiment.

7-2] Fig. 7-2 is an enlarged explanatory view showing an important part of the printing procedure of the third embodiment.

8-1] FIG. 8-1 shows the printing of the fourth embodiment of the printing method of the present invention. A cross-sectional view of an important part of the brush device.

8-2] Fig. 8-2 is a cross-sectional view showing an essential part of a printing apparatus according to a fourth embodiment of the printing method of the present invention.

Fig. 9-1 is a cross-sectional view showing the steps of the printing principle of the printing method according to the fourth embodiment of the present invention.

Fig. 9-2 is a cross-sectional view showing the steps of the printing principle of the printing method according to the fourth embodiment of the present invention.

9-3] Fig. 9-3 is a cross-sectional view showing the steps of the printing principle of the printing method according to the fourth embodiment of the present invention.

Fig. 9-4 is a cross-sectional view showing the steps of the printing principle of the printing method according to the fourth embodiment of the present invention.

Fig. 9-5 is a cross-sectional view showing the steps of the printing principle of the printing method according to the fourth embodiment of the present invention.

Fig. 10-1 is a cross-sectional view showing the steps of the printing principle of the fifth embodiment of the printing method of the present invention.

Fig. 10-2 is a cross-sectional view showing the steps of the printing principle of the fifth embodiment of the printing method of the present invention.

Fig. 10-3 is a cross-sectional view showing the steps of the printing principle of the fifth embodiment of the printing method of the present invention.

Fig. 10-4 is a cross-sectional view showing the steps of the printing principle of the fifth embodiment of the printing method of the present invention.

Fig. 10-5 is a cross-sectional view showing the steps of the printing principle of the fifth embodiment of the printing method of the present invention.

10-6] FIG. 10-6 shows Embodiment 5 of the printing method of the present invention. A cross-sectional view of the steps of the printing principle.

Fig. 11-1 is a cross-sectional view showing the steps of the printing principle of the printing method according to the sixth embodiment of the printing method of the present invention.

Fig. 11-2 is a cross-sectional view showing the steps of the printing principle of the printing method according to the sixth embodiment of the printing method of the present invention.

Fig. 12 is an enlarged perspective view showing an essential part of a plate used in the printing method according to the sixth embodiment of the printing method of the present invention.

Fig. 13 is an enlarged cross-sectional view showing an essential part of a plate used in the printing method according to the sixth embodiment of the printing method of the present invention.

Fig. 14-1 is a view showing a light receiving surface of a solar cell formed by the printing method of the seventh embodiment using the printing method of the present invention.

Fig. 14-2 is a rear view showing the opposite side of the light receiving surface of the solar cell shown in Fig. 14-1.

Fig. 14-3 is a cross-sectional view showing the solar cell.

14-4] Fig. 14-4 shows an enlarged perspective view of an important part of a plate for forming a light-receiving surface side electrode of a solar cell.

Fig. 15-1 is a cross-sectional view showing the steps of the printing principle of the printing method according to the eighth embodiment of the printing method of the present invention.

Fig. 15-2 is a cross-sectional view showing the steps of the printing principle of the printing method according to the eighth embodiment of the printing method of the present invention.

Fig. 15-3 is a cross-sectional view showing the steps of the printing principle of the printing method according to the eighth embodiment of the printing method of the present invention.

Fig. 16 is a view showing a modification of the plate used in the printing method of the eighth embodiment of the printing method of the present invention.

Fig. 17 is a view showing a plate used in a printing apparatus according to a ninth embodiment of the printing method of the present invention.

Fig. 18 is a view showing a plate used in the printing apparatus according to the tenth embodiment of the printing method of the present invention.

Embodiment 1.

Hereinafter, embodiments of the printing method and printing apparatus of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and may be appropriately modified and implemented without departing from the scope of the invention. In addition, the drawings shown below are easy to understand, and the scales of the respective members may differ from the actual ones. The same is true between the drawings.

1-1 to 1-5 are cross-sectional views showing the steps of the printing principle of the printing method according to the first embodiment of the printing method of the present invention. Fig. 2 is a schematic view showing a printing apparatus which carries out the printing method of the first embodiment. In the present embodiment, the printing material is filled with two layers of the first and second pastes 14a and 14b, and is filled in a two-layer structure to increase the aspect ratio, and is transferred to the solar cell substrate 20 of the object to be printed. This printing apparatus forms a plate 11 on the surface of a drum 10, and performs various steps in accordance with the rotation of the cylinder 10. That is, the plate 11 has a concave pattern formed by the arrangement of the groove-shaped recesses 12 on the surface, and the filling portion is provided with a squeegee 13 for filling the printed material into the recess 12 of the plate 11; The printing material is transferred to the printing surface 20S of the solar cell substrate 20. In the present embodiment, the transfer portion includes the pressing portion 30, and the first and second pastes 14a and 14b can be mechanically pressed onto the printing surface 20S by the concave portion 12. The pressing portion 30 has an air supply space 31 and a supply hole 34 for supplying air, and the printing material is extruded by supplying air to the air supply space 31 and passing through the supply hole 34. Figures 1-1 to 1-5 show the circumference of the cylinder 10 of Figure 2 One part of the face, in fact, forms part of the circumference, and is only briefly shown in plan view.

Fig. 1-1 is a view showing an initial state in which a groove-like recess 12 having a shape to be printed is dug in the plate 11.

As shown in the first paste filling step of FIG. 1-2, the recess 12 is filled with the paste (first paste 14a). As is apparent from Fig. 2, the first paste 14a is held between the blade 13 and the plate 11, and the blade 13 is fixed to a portion of the surface of the plate 11 attached to the surface of the cylinder 10, and the blade 13 is rotated along with the rotation of the cylinder 10. The first paste 14a is supplied into the concave portion 12 on the surface of the plate 11.

As shown in the drying step of FIG. 1-3, the drying portion composed of the air blowing portion 15 performs air blowing to dry the first paste 14a. By drying to volatilize the organic components in the paste, the volume of the paste is reduced to produce a depressed portion R on the surface.

As shown in the second paste filling step of FIG. 1-4, the depressed portion R on the surface of the first paste 14a is further filled with the second paste 14b.

As shown in the transfer step of FIGS. 1-5, the air supply space 31 of the pressing portion 30 is supplied with air pressure through the supply hole 34. In this manner, the first and second pastes 14a and 14b in the concave portion 12 are mechanically pressed by air pressure to be printed on the printing surface 20S of the solar cell substrate 20 of the object to be printed.

Since the dried first paste 14a is solidified in the concave portion 12, the shape can be maintained even when it is pressed by the concave portion 12 by a mechanical method. On the other hand, the adhesion of the first paste 14a can be eliminated by drying, and the paste cannot be stopped at a specific position on the printing surface 20S of the solar cell substrate 20 of the object to be printed when printing is performed in this state.

Therefore, in the present embodiment, it is in the depressed portion R generated by the drying. The filling of the paste (second paste 14b) was carried out. The second paste 14b that has been filled again is not dried before printing, and the adhesive force is not lost. Therefore, the second paste to be printed can stay at a specific position on the printing surface 20S of the solar cell substrate 20 of the object to be printed. As described above, the concept of the printing method according to the first embodiment is that the thickness of the electrode is contributed by the dried paste, and the adhesive position of the undried paste can stay at a specific position on the object to be printed.

For example, in the conventional method disclosed in Patent Documents 1 and 2, the positioning of the second and subsequent printing becomes important because the printing is performed plural times, but the positioning of the printing becomes difficult after the electrode is thinned for the second time. On the other hand, in the method of the present embodiment, printing is performed after a series of steps such as drying and filling of the paste in the same groove-like recess 12, so that it is possible to realize printing of a high aspect ratio electrode without complicated positioning work.

In addition, conventional photogravure has a problem of poor transfer rate. This is caused by the difference between the area where the paste contacts the printed matter and the area where the paste contacts the pattern. In the gravure printing or offset printing, the paste filled in the groove (pattern)-like concave portion is transferred by the groove-like concave portion by the adhesion of the printed matter and the paste. Therefore, in order to perform printing, it is necessary to "the adhesion between the inner wall of the groove and the paste <the adhesion between the printed matter and the paste". However, in general, "the contact area between the printed matter and the paste < the contact area between the groove-like recess and the paste (= surface area of the inner wall of the depressed portion)" is thus present at the place where it is not transferred. Based on this background, there is a technique disclosed in Patent Document 2. In the embodiment of the present invention, the filled paste is pressed by the groove-like recess to the surface of the solar cell substrate which is subjected to the desired process before the electrode printing step, so that the transfer rate can be improved.

The first paste and the second paste do not necessarily have to be the same paste, and may be different pastes. For example, even if the Ag paste is used, the composition may have a different composition or viscosity, and the first paste may be an Ag paste, and the second paste may be a different material such as a Cu paste. The paste can also be. By covering the periphery of the second paste with the first paste, the second paste can be prevented from coming into contact with the atmosphere. Therefore, it is possible to set the second paste to a material having low resistance such as Cu but which is easily oxidized, and to set the first paste to be difficult to oxidize. Further, the first paste may be a single metal such as a metal wire.

Embodiment 2.

3-1 to 3-4 are cross-sectional views showing the steps of the printing principle of the printing method according to the second embodiment of the printing method of the present invention. Fig. 4 is a schematic view showing a printing apparatus for carrying out the printing method of the second embodiment. Similarly to the printing apparatus according to the first embodiment, the printing apparatus forms the plate 11 on the surface of the cylinder 10, and performs the respective steps simultaneously with the rotation of the cylinder 10, and the metal wire 14m is supplied instead of the first filling portion. The supply portion 16 of the recess 12 is a feature. That is, the first printing material uses a metal wire 14m. The filling of the paste 14 is performed so as to surround the metal wire 14m by the doctor blade 13 constituting the filling portion. Therefore, the device does not require the air blowing portion 15 constituting the drying portion. The pressing portion 30 has an air supply space 31 and a porous portion 33, and is configured by supplying air to the air supply space 31 and perforating the printing material through the porous portion 33. Others are the same as those of the first embodiment described above, and thus the description thereof is omitted.

In the present embodiment, the paste 14 is filled in a state in which the metal wires 14m are disposed, and the paste is filled so as to surround the metal wires. Therefore, the electrodes having a high aspect ratio can be easily and efficiently formed.

Fig. 3-1 is a view showing an initial state in which a groove-like recess 12 having a shape to be printed is dug in the plate 11.

Thereafter, as shown in the first filling step of FIG. 3-2, in the recess 12 Fill the metal wire 14m.

Thereafter, as shown in the paste filling step of FIG. 3-3, the paste 14 is filled so as to cover the periphery of the metal wire 14m in the recess 12.

As shown in the transfer step of FIG. 3-4, the air supply space 31 of the pressing portion 30 passes through the porous portion 33 to apply air pressure to the concave portion 12. In this manner, the metal wires 14m and the paste 14 in the concave portion 12 are extruded by a mechanical method of air pressure, and printed on the printing surface 20S of the solar cell substrate 20 of the object to be printed.

Embodiments of the invention are also applicable to the formation of such electrodes. As shown in FIG. 4, the metal wire 14m is placed in the concave portion 12 instead of the first paste, and the paste 14 made of a conductive adhesive is filled thereon to perform printing, whereby a surface electrode having a low electrical resistance and a high aspect ratio can be formed.

Embodiment 3.

5-1 to 5-4 are cross-sectional views showing the steps of the printing principle of the printing method according to the third embodiment of the printing method of the present invention. Fig. 6 is a schematic view showing a printing apparatus for carrying out the printing method of the third embodiment, and Figs. 7-1 to 7-2 are enlarged explanatory views of important parts of the step. Similarly to the printing apparatus of the first embodiment, the printing apparatus forms the plate 11 on the surface of the cylinder 10, and performs the respective steps simultaneously with the rotation of the cylinder 10. The hardness of the first scraper 13a is set to be lower than the first scraper 13a constituting the first filling portion and the air blowing portion 15 constituting the drying portion. Others are the same as those of the first embodiment described above, and thus the description thereof is omitted. However, the air blowing portion 15 may be provided in the same manner as in the first embodiment described above. Further, the plate 11 may be heated to dry only the outer circumferential surface of the concave portion 12 or to blow air from the inner wall of the concave portion.

Fig. 5-1 is a view showing an initial state in which a groove-like recess 12 having a shape to be printed is dug in the plate 11.

Thereafter, as shown in the first paste filling step of FIG. 5-2, the paste (first paste 14a) is filled in the concave portion 12. At this time, the first paste 14a is held between the first blade 13a and the plate 11, and the first blade 13a is fixed to a portion of the surface of the plate 11 disposed on the surface of the cylinder 10. As shown in FIG. 7-1, since the scraper of low hardness is used, the first scraper 13a is bent into the concave portion 12 in accordance with the rotation of the cylinder 10. In this way, the first paste 14a can be supplied in such a manner that the surface has the depressed portion R.

Thereafter, the second paste 14b is filled in the depressed portion R by the second doctor blade 13b as shown in the second paste filling step of FIG. 5-3 without the drying step. At this time, as shown in Fig. 7-2, the second paste 14b is held between the second blade 13b and the plate 11, and the second blade 13b is fixed to the surface of the plate 11 disposed on the surface of the cylinder 10. portion. Since the blade having a high hardness is used, the supply of the second paste 14b can be performed with the rotation of the cylinder 10 and when the second blade 13b is not bent in the concave portion 12.

As shown in the transfer step of Fig. 5-4, the air supply space 31 of the pressing portion 30 is supplied with air pressure through the supply hole 34. In this manner, the first and second pastes 14a and 14b in the concave portion 12 are pressed by a mechanical method of air pressure, and printed on the printing surface 20S of the solar cell substrate 20 of the object to be printed.

In the present embodiment, the filling of the paste (second paste 14b) is performed again by the depressed portion R on the surface of the first paste 14a which is generated by the bending of the blade. The second paste 14b that has been filled again is not dried before being transferred, so that the adhesive force is not lost, and the second paste to be printed can be stopped at a specific position on the printing surface 20S of the solar cell substrate 20 of the object to be printed. As described above, the printing method according to the third embodiment is that the thickness of the electrode is contributed by the first paste to form a depressed portion, and the adhesive force of the second paste can stay at a specific position on the object to be printed.

The use of a very high viscosity paste as the first paste can shorten (or omit) the subsequent drying step time, but the volume reduction caused by drying is less, and the second paste may not be filled and left to be specific to the printed matter. position. At this time, it is possible to reduce the hardness of the blade (blade) used for filling the first paste. When a high-hardness scraper such as a metal scraper is used, the paste is filled in the entire groove-like recess and the second paste filling region cannot be secured. However, the blade can be bitten into the recess 12 by reducing the blade hardness, and can be formed on the surface. The depressed portion R ensures the filling area of the second paste.

In the above-described first and third embodiments, the first and second pastes are used. However, the two pastes are not limited, and the same printing can be performed for three or more pastes. In addition, different kinds of pastes or pastes of the same kind can be used.

Embodiment 4.

8-1 and 8-2 are views showing a printing apparatus used in the fourth embodiment of the printing method, and Figs. 9-1 to 9-5 are printing principles showing the printing method according to the fourth embodiment of the printing method of the present invention. Step profile view. This printing apparatus uses a flat plate type 41 and has a function of easy transfer. A paste extrusion method characterized by filling the groove-like recess 42 of the plate 41. As shown in FIGS. 8-1 and 8-2, the plate 41 is a flat plate and has a concave portion 42 arranged to constitute an opening portion to be printed, and a stretch film 43 is provided under the plate 41, and the plate 41 and the stretch film 43 are provided. The system is fixed. The stretch film 43 is formed of a rubber or a silicone rubber or the like. The depth of the groove-like recess 42 may be equal to the plate thickness or less than the plate thickness. When the depth of the groove-shaped recessed portion 42 is less than the plate thickness, the suction hole 44 is provided. On the upper side of the plate (opposite side of the stretch film 43), there is a closed space 45, and the air in the space is attracted to make the air pressure in the closed space 45 become a lower air pressure, and the stretch film 43 is formed along the groove formed in the plate 41. The shape of the recess 42 is depressed (Fig. 8-2). Here, the first paste 14a is filled, and then the second paste 14b is filled. When the plate 41 is set on the front surface of the solar cell substrate 20 of the object to be printed, and the suction in the sealed space 45 is released, the paste filled in the depressed portion can be squeezed out and printed on the solar cell by the restoring force of the stretch film 43. The surface of the substrate 20.

In the printing apparatus according to the first embodiment, a drum-shaped plate 11 is used. In the present embodiment, the plate 41 has a flat plate shape. This printing apparatus includes a plate 41 in which groove-like recesses 42 corresponding to the printed shape are arranged, and a bellows 42 facing the plate 41, and is attached to the stretch film 43 of the plate 41. Each of the concave portions 42 is provided with a suction hole 44 that communicates with each other, and is configured by suction from the suction hole 44 to suck the air inside the concave portion 42. A sealed space 45 that attracts a plurality of suction holes 44 is integrated in the interior of the plate 41, and the suction holes 44 communicate with the sealed space 45, respectively. Further, the sealed space 45 can be connected to the pressurizing pipe 47 through a pressure valve 46a. The pressurizing pipe 47 is connected to the atmosphere, and the sealed space 45 can be pressurized to atmospheric pressure. On the other hand, the sealed space 45 is connected to the suction pipe 48 through the suction valve 46b, and the suction pipe 48 is connected to a vacuum pump (not shown).

Fig. 8-1 shows a state in which the suction valve 46b is closed and the pressure valve 46a is opened. By setting the suction valve 46b to be closed and the pressure valve 46a to be opened, the sealed space 45 can be pressurized to the atmospheric pressure state, and the inside of the concave portion 42 is also pressurized to the atmospheric pressure state. Since both sides of the stretch film 43 are in an atmospheric pressure state, the stretch film 43 is not subjected to the expansion and contraction force, and the stretch film 43 is in a flat state.

Fig. 8-2 shows a state in which the suction valve 46b is opened and the pressure valve 46a is closed. When the suction valve 46b is opened and the pressure valve 46a is closed, the sealed space 45 is evacuated, and the inside of the recess 42 is also made to have a large air pressure. Therefore, the stretch film 43 is bent inward by the action of the stretching force, and the stretch film 43 is along the recess 42 The inner wall is sunken to form a recess.

The first and second pastes 14a and 14b are supplied by sliding the first and second scrapers 13a and 13b on the surface of the plate 41. In the same manner as in the above-described third embodiment, the first scraper 13a constituting the first filling portion is made of a low-hardness member, and the depressed portion R can be formed on the surface of the first paste 14a by being bent in the concave portion 42. Therefore, the device does not necessarily need the air blowing portion 15 constituting the drying portion.

Fig. 9-1 is a view showing an initial state in which the groove-like recessed portion 42 to be printed is dug in the plate 41. In the state of Fig. 8-1, both sides of the stretchable film 43 are in an atmospheric pressure state, so that the stretchable film 43 is not subjected to the expansion and contraction force, and the region around the concave portion 42 of the stretchable film 43 is followed by the plate 41 to be flat.

Next, the operation of the printing apparatus is performed as shown in Fig. 8-2. As shown in FIG. 9-2, the air in the sealed space 45 which is present on the upper side of the suction plate 41 (the opposite side of the stretch film 43) is sucked by the suction hole 44 so that the air pressure in the sealed space 45 is lower than the atmospheric pressure. The stretch film 43 sinks along the desired shape.

Next, as shown in FIG. 9-3, the first paste 14a is filled with the first doctor blade 13a. Similarly to the first paste filling step shown in FIG. 5-2, the paste (first paste 14a) is filled in the concave portion 42 using the first blade 13a having a low hardness. At this time, the first paste 14a is held between the first scraper 13a fixed to one of the surfaces of the plate 41 and the plate 41, and the first scraper 13a having a low hardness is used, so that the first scraper 13a can be bent in the concave portion 42. . In this way, the first paste 14a can be supplied in such a manner that the surface has the depressed portion R.

Then, as shown in the second paste filling step of FIG. 9-4, the second paste 14b is further filled in the depressed portion R by the second scraper 13b while the suction valve 46b is opened and the pressurizing valve 46a is closed. After the second paste filling step, though Although it is a drying process, it is only necessary to dry at least the outer surface of the 1st paste, and it is not necessary to have a drying process.

As shown in Fig. 9-5, the plate 41 is set on the front surface of the object to be printed, the suction by the suction hole 44 is stopped, and the suction of the sealed space 45 is released, and the stretch film 43 is restored, and the groove-shaped recess 42 is restored to its original size. At this time, the first and second pastes filled in the depressed portion are extruded by the restoring force of the stretchable film 43 and printed on the object to be printed. In this manner, the first and second pastes 14a and 14b in the concave portion 42 are extruded by a mechanical method of air pressure, and printed on the printing surface 20S of the solar cell substrate 20 of the object to be printed. In this embodiment, an electrode having a high aspect ratio can be formed.

Embodiment 5.

10-1 to 10-6 are cross-sectional views showing the steps of the printing principle of the printing method according to the fifth embodiment of the printing method of the present invention. In the printing apparatus, the stretchable film 43 is used in the same manner as in the fourth embodiment, but the size of the concave portion of the filling paste is changed by adjusting the suction force in two stages. When the first paste 14a is filled, the suction force is lowered, and the stretch film 43 is sucked so as to leave a space between the inner wall of the concave portion 42. After the filling, the suction force is increased, and the stretch film 43 is increased along the inner wall of the concave portion 42 to increase the size of the concave portion of the filling paste, so that the depressed portion R is formed on the surface of the first paste 14a.

Fig. 10-1 is a view showing an initial state. Similarly to the above-described fourth embodiment shown in Fig. 9-1, the groove 41 of the shape to be printed is excavated in the plate 41. Both sides of the stretchable film 43 are in an atmospheric pressure state, and the stretchable film 43 is not subjected to the expansion and contraction force, and the stretched film 43 is placed in a flat state around the plate 41 in the region around the concave portion 42.

The printing unit is then operated as shown in Figure 8-2. Thus, as shown in FIG. 10-2, the air existing in the sealed space 45 on the upper side of the plate 41 (opposite side of the stretch film 43) is such that a space remains between the inner wall of the recess 42 and the inner wall of the recess 42. The low attraction force is attracted, and the stretch film 43 is attracted. When the suction hole 44 is attracted, the air pressure of the sealed space 45 becomes slightly lower than the atmospheric pressure, and thus the stretch film 43 is slightly sunken along the desired shape.

Thereafter, as shown in Fig. 10-3, the filling of the first paste 14a is performed using the doctor blade 13.

Next, without passing through the drying step, as shown in Fig. 10-4, the attraction force is increased so that the stretch film 43 is along the inner wall of the recess 42 and the size of the recess of the filling paste is increased. At this time, the concave portion becomes large, and the depressed portion R is formed on the surface of the first paste 14a. The drying step is then carried out as necessary.

Next, as shown in the second paste filling step of FIG. 10-5, the suction valve 46b is opened to maintain a strong suction state, and the depressed portion R is further filled with the second paste 14b.

As shown in Fig. 10-6, the plate 41 is set on the front surface of the object to be printed, the suction by the suction hole 44 is stopped, and the suction of the sealed space 45 is released, and the stretch film 43 is restored, and the groove-shaped recessed portion 42 returns to its original size. At this time, the first and second pastes filled in the depressed portion are extruded by the restoring force of the stretch film 43 and printed on the object to be printed. The first and second pastes 14a and 14b in the concave portion 42 are extruded by a mechanical method of air pressure, and printed on the printing surface 20S of the solar cell substrate 20 of the object to be printed.

As described above, in the fourth and fifth embodiments, the paste is extruded by the depressed portion by the restoration of the stretchable film, and the contact area between the printed surface of the printed matter and the paste is larger than the contact area between the stretched film and the paste, so that the contact area can be improved. The transfer rate of the printed material. Further, since the depth of the depressed portion can be adjusted by the adjustment of the attractive force, the thickness of the printed paste can be adjusted, so that the printing force can be performed without lowering the transfer rate by the restoring force of the stretchable film. Therefore, it is possible to print by one time. A high aspect ratio printed matter. Further, the suction spaces can be made independent of each region, and the printed patterns (electrodes) of different thicknesses can be formed by the adjustment of the attractive force. In the present embodiment, the scraper 13 used for filling the first paste and the second paste is the same. However, as in the above embodiment, a low-hardness scraper can be used in the first paste filling.

As described above, according to the present embodiment, in the first filling step, after the concave portion corresponding to the printing shape is filled with the first printing material, the surface of the concave portion is enlarged and the surface of the first printing material is depressed, and the second printing material can be formed. A pattern with good adhesion. Further, by supplying air to the suction holes at the time of transfer, the printing material (first paste and second paste) filled in the filling space of the printing material can be easily extruded by the restoring force of the stretch film.

Embodiment 6.

11-1 to 11-2 are cross-sectional views showing the steps of the printing method in the sixth embodiment of the printing method of the present invention. This printing apparatus is similar to the fourth and fifth embodiments in that the stretchable film 43 is used. However, instead of adjusting the attractive force to form printed patterns (electrodes) of different thicknesses, recesses of different depths are used to form printed patterns of different thicknesses. By.

The plate 41 to be used is formed by mixing a deep first concave portion (sag portion) 42a and a shallow second concave portion (sag portion) 42b depending on the position of the pattern. Fig. 11-1 shows an initial state, and Fig. 11-2 shows a state in which a stretching force is applied to the stretch film 43 by suction.

By using such a plate 41 having recesses of different depths to form a solar cell, a printed pattern having a locally different thickness can be formed on the solar cell. For example, by thickening only the grid electrode, you can reduce it further. The resistance of the grid electrode with large resistance loss.

The plate of the stretch film 43 of the fourth, fifth, and sixth embodiments is enlarged as shown in the outline of the plate 41 shown in Fig. 12, because the opening end E of the recess 42 contacts the stretch film 43, which is advantageous. The stretched stretch film 43 is shortened to shorten the life of the stretchable film 43 and deteriorate productivity. Therefore, as shown in the enlarged cross-sectional view of the important portion of the plate 41 of Fig. 13, the rounding of the corner 41E must be performed at the intersection of the opening end E, that is, at the line constituting the end face, to alleviate the contact with the stretch film 43. .

Embodiment 7.

Next, a solar cell in which an electrode is formed using the printing method of the embodiment will be described. Fig. 14-1 is a view showing a light receiving surface of a solar cell formed by using the printing method according to the embodiment of the present invention. Fig. 14-2 is a rear view showing the opposite side of the light receiving surface of the solar cell shown in Fig. 14-1. Figure 14-3 is a cross-sectional view. Fig. 14-4 is an enlarged perspective view showing an important part of a plate for forming a light-receiving surface side electrode of a solar cell. On the light receiving surface of the solar cell substrate 20, a grid electrode 24G and a table auxiliary electrode 24B which are arranged orthogonally to each other are provided. A back surface electrode 23 made of aluminum and a back auxiliary electrode 24RB are provided on the back surface of the solar cell substrate 20.

The grid electrode 24G, the table bus electrode 24B, and the back auxiliary electrode 24RB of the solar cell formed by the printing method of the first embodiment are formed by a two-layer structure of the first paste 14a and the second paste 14b. An electrode that constitutes a high aspect ratio and high reliability. In addition, the second paste covers the entire outer peripheral surface of the first paste, and has a large contact area, and not only the adhesion is good, but also the contact resistance is low.

Further, in the flat plate 61, the area surrounded by the mesh electrode portion 63 and the table auxiliary electrode portion 62 cannot be held, and therefore, in this case, it is as shown in the figure. As shown in FIG. 14-4, a rib 64 is provided between the groove-like recess and the groove-shaped recess to form a table auxiliary electrode portion 62.

Further, although the above-described seventh embodiment is formed by the printing method of the first embodiment, any one of the printing methods and printing apparatuses of the first to sixth embodiments may be used.

Embodiment 8.

Figs. 15-1 to 15-3 are cross-sectional views showing the steps of the printing principle of the printing method according to the eighth embodiment of the printing method of the present invention. This printing apparatus uses a flat plate-shaped thick plate 71 and has a function of easy transfer. In the present embodiment, the plate 71 is formed by providing a groove-shaped recess 72, that is, an opening portion, in a thick metal plate. Although not shown, there is a sealed space above the plate 71. The paste is filled in this version 71.

Fig. 15-1 is a view showing an initial state in which a groove-like recess 72 to be printed is cut out in the plate 71.

Thereafter, as shown in Fig. 15-2, the first and second pastes 14a and 14b are filled here. At this time, the first and second pastes 14a and 14b are filled with the outer side of the plate 71 (the side in contact with the object to be printed). At this time, it is attempted that the paste cannot be completely filled in the depth direction of the groove (pattern)-like recess 72. In this way, it is possible to prevent the paste filled in the groove-like recess 72 from overflowing to the back surface of the mask. To make this state, it is only necessary to set the thickness of the plate to be sufficiently thick, or to set the depth of the groove-like recess 72 to be sufficiently deep. The thickness of the printing is estimated to be as large as 0.1 mm or less, so that the thickness of the sheet (the depth of the groove) is sufficient as long as it is several hundred μm or more.

Finally, as shown in Fig. 15-3, the paste (the first and second pastes 14a, 14b) in the groove-like recess 72 is pressed onto the solar cell substrate 20 by the air pressing by the pressing portion 30. . Further, in the above embodiment, the paste is composed of one type. However, after a series of operations such as filling of the first paste 14a, drying, and filling of the second paste 14b, the pressure in the sealed space is pressed to press the paste in the groove.

Further, as in the modification of the plate shown in Fig. 16, it is also possible to use a groove-like recess 72 which is a supply hole 74 for supplying air so that the paste is pressed in the transfer step. It's easier.

Embodiment 9.

Fig. 17 is a view showing a plate used in the printing apparatus according to Embodiment 9 of the present invention. This plate 81 is a plate using a porous body. A blocking layer 83 that blocks the air 84 is provided in a region other than the pattern of the groove-like recesses 82 on the surface of the plate 81 made of a porous body. Although not shown, a sealed space is present on the plate 81, and the sealed air is sealed, and the first and second pastes 14a and 14b filled in the groove-shaped recess 82 can be pressed to the solar cell by the air 84 leaking from the hole. The surface of the substrate 20.

According to this device, the air 84 is ejected from the porous body existing in the entire inner wall of the concave portion, and the paste can be easily pressed onto the surface of the solar cell substrate 20 by the groove-like recess 82.

Further, according to the present embodiment, the plate 81 made of a porous body is used, and air can be uniformly supplied to the entire outer peripheral surface of the first paste 14a to be dried. On the other hand, the first paste containing the inner depressed portion is not provided. When the inside of 14a is dried, the supply of the second paste 14b is performed. Therefore, the adhesion between the first paste 14a and the second paste 14b can be maintained good. Further, the outer surface of the first paste 14a is dried, and the transfer property is good.

In addition, after the first paste 14a is filled, the plate 81 made of a porous body is heated and air-dried by warm air, whereby the transfer property can be more effectively improved.

Embodiment 10.

Fig. 18 is a view showing a plate used in the printing apparatus according to the tenth embodiment of the present invention. This plate is a plate 91 in which a piston 92 is disposed in a groove, and the first and second pastes 14a and 14b filled in the groove-like recesses are pressed against the surface of the solar cell substrate 20 by the piston 92.

According to this device, the paste (the first and second pastes 14a and 14b) can be easily pressed onto the surface of the solar cell substrate 20 by the piston 92 by the groove-shaped recess corresponding to the printed pattern.

In the above-described first to sixth embodiments, the method of filling the paste is described. In the eighth to tenth embodiments, the method of transferring the paste is described. However, any method may be combined as far as possible. Further, these printing methods and printing apparatuses are suitable not only for electrode formation of solar cells, but also for forming various conductor patterns such as electrode formation on a wiring board and electrode formation on a glass substrate such as a liquid crystal panel.

[Industrial Availability]

As described above, the printing method and the printing apparatus of the present embodiment are not only applicable to printing using a flat plate, but also to printing using a cylindrical plate. By using a rotating cylindrical plate, it is possible to have a high productivity function of the advantages of gravure printing and offset printing.

10‧‧‧Cylinder

11‧‧ version

12‧‧‧ recess

13‧‧‧Scraper

14a‧‧‧1st paste

14b‧‧‧2nd paste

15‧‧‧Air Supply Department

20‧‧‧Solar battery substrate

30‧‧‧Extrusion Department

31‧‧‧Air supply space

34‧‧‧Supply hole

R‧‧‧Sag

Claims (9)

A printing method comprising: a first filling step of filling a first printing material in a concave portion of a plate, wherein the plate has a pattern formed by arranging the concave portions in a groove shape on a surface; drying step Filling the filled first printing material with a second filling step of filling the second printing material with the concave portion filled with the first printing material; and transferring the second printing material Before drying, the first and second printing materials are mechanically pressed onto the printing surface of the printed matter by the concave portion to transfer the first and second printing materials; wherein the first filling step is performed Sliding on the surface of the plate, and flattening the hardness of the blade used for the surface of the first printing material to be flat on the surface of the plate in the second filling step, and leveling the second printing material The blade used for the surface has a low hardness, and the first filling step is a step of filling the surface of the first printing material so as to be depressed, and printing on the printing surface of the object to be printed. The printing method according to claim 1, wherein in the first filling step, after filling the first printing material in the concave portion, the internal volume of the concave portion is enlarged to cause the surface of the first printing material to sag. A printing apparatus comprising: a plate having a pattern formed by arrangement of groove-like recesses on a surface thereof; and a first filling portion filling a first printing material with the recessed portion of the plate; The drying unit dries the first printing material filled in the concave portion, the second filling portion fills the concave portion with the second printing material, and the transfer portion mechanically fills the first portion of the concave portion The second printing material is pressed onto the printing surface of the object to be printed and transferred onto the printing surface; wherein the hardness of the blade used in the first filling portion is lower than the hardness of the blade used in the second filling portion, and is configured to be The surface of the first printing material filled in the concave portion may be curved to be printed on the printing surface of the printed matter. The printing device according to claim 3, wherein the concave portion is configured to expand an internal volume after the filling of the first printing material to cause the surface of the first printing material to sag. The printing device of claim 3, wherein the plate has a stretch film that is attached to the recess; and a suction hole that communicates with each of the recesses; and the suction from the suction hole The air inside the concave portion is attracted to form a printing material filling space. The printing device according to claim 5, wherein the transfer portion supplies air to the suction hole, and the printing material filled in the printing material filling space is pressed by a restoring force of the stretch film. The printing device of claim 3, wherein the plate is made of a porous body and has a blocking layer having an opening corresponding to the recess and being attached to the plate. The air supply unit is configured to supply air to the recessed portion, and the air is supplied from the air supply unit to extrude the printing material inside the recess. A method for producing a solar cell, comprising: a first filling step of filling a first printing material by forming the concave portion of a plate having a pattern formed by arrangement of groove-like recesses; and drying step The filled first printing material is dried; the second filling step is to fill the concave portion filled with the first printing material with the second printing material; and the transferring step is before the drying of the second printing material Transferring the first and second printing materials by mechanically pressing the concave portion to the surface of the solar cell substrate of the desired process before the electrode printing step, wherein the first and second printing materials are transferred; In the first filling step, the hardness of the blade used when the concave portion is filled with the first printing material and then slid on the surface of the plate to level the surface of the filled first printing material is set to be larger than In the filling step, after the concave portion is filled with the second printing material, and then slid on the surface of the plate to flatten the surface of the second printing material to be filled A low hardness with a doctor blade, the first step of the filling, so that the surface of the first printing material is then depressed manner filling step is performed, printing is performed on the printing surface of the solar cell substrate. The method for manufacturing a solar cell according to item 8 of the patent application, wherein the above In the filling step, after the first printing material is filled in the concave portion, the internal volume of the concave portion is enlarged to cause the surface of the first printing material to sag.