JP2006210832A - Method and device for connecting display panel, and flexible circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the generation of the floating of the base film of a flexible circuit board, when connected display panel and flexible circuit board are left at a high temperature and high-moisture atmosphere, without subjecting the board to aging process after connection, at electrical connection of the terminal section of the display panel and the terminal section of the flexible circuit board, by using connecting materials constituted by mixing conductive particles in ultraviolet-curing resin. <P>SOLUTION: A pressurizing bar 24 butted to the surface of a terminal 32 of a flexible circuit board 30 for applying pressure to the terminal of a flexible circuit board and connecting materials 34, and a terminal 28 of a display panel 26 is provided with a heating means 50. Then, the terminal of the flexible circuit board and the connecting materials are heated by the heating means, when the connecting materials are irradiated with ultraviolet rays. It is desired that the terminal of the flexible circuit board and the connecting materials be heated by the heating means, after the lapse of a predetermined time since the start of the irradiation of the ultraviolet rays. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a connection between a display panel and a circuit board for electrically connecting the terminal part of the display panel and the terminal part of the flexible circuit board using a connecting material obtained by mixing conductive particles in an ultraviolet curable resin. The present invention relates to a method and a connection device.

  Conventionally, a connection used when electrically connecting a terminal portion of a liquid crystal panel, which is one of display panels, and a terminal portion of a flexible circuit board using a connecting material obtained by mixing conductive particles in an ultraviolet curable resin. A device shown in FIG. 3 is known as an apparatus (see, for example, Patent Document 1).

  In the connecting device of FIG. 3, 10 is a liquid crystal panel support, 12 is a flexible circuit board support placed on the side of the liquid crystal panel support 10 and spaced apart from the liquid crystal panel support 10, and 14 is a liquid crystal panel support. 10 is a terminal support base made of an ultraviolet light transmissive material disposed between the flexible circuit board support base 12, 18 is an ultraviolet irradiation means disposed below the terminal support base 14, and 24 is a terminal support base 14. The pressure bar which can be moved up and down installed above is shown. The ultraviolet irradiation means 18 includes an ultraviolet lamp 20 and an ultraviolet reflector 22.

  When connecting the terminal portion 28 of the liquid crystal panel 26 and the terminal portion 32 of the flexible circuit board 30 using the connection device of FIG. 3, the surface of the terminal portion 28 of the liquid crystal panel 26 (the surface on which the electrode terminals are formed). Then, a connecting material 34 obtained by mixing conductive particles in an ultraviolet curable resin is laminated by coating, printing, or the like. Further, the liquid crystal panel 26 is placed on the liquid crystal panel support 10, the terminal portion 28 of the liquid crystal panel 26 is disposed on the terminal portion support 14, and the flexible circuit board support 12 is placed on the terminal portion 28 of the liquid crystal panel 26. The terminal portions 32 of the flexible circuit board 30 placed thereon are overlaid. In the liquid crystal panel 26, 27 and 27 are transparent substrates, and 29 and 29 are polarizing plates.

  Thereafter, as shown in FIG. 4, the pressure bar 24 is lowered and the tip pressing surface 25 presses the portion of the surface of the flexible circuit board 30 (the surface on which the electrode terminals are not formed) superimposed on the liquid crystal panel 26. Then, pressure is applied to the terminal portions 32 of the flexible circuit board 30, the connecting material 34, and the terminal portions 28 of the liquid crystal panel 26, and these are crimped. Further, in this state, the ultraviolet ray irradiating means 18 irradiates the connection material 34 with ultraviolet rays 21, thereby curing the ultraviolet curable resin in the connection material 34 and electrically connecting both terminal portions 28 and 32. In the figure, reference numeral 36 denotes a cushion material disposed between the front end pressing surface 25 of the pressure bar 24 and the surface of the flexible circuit board 30.

JP 2003-168858 A

  However, as described above, the terminal portion of the liquid crystal panel and the terminal portion of the flexible circuit board are connected using a connecting material obtained by mixing conductive particles in an ultraviolet curable resin, and the liquid crystal panel and the flexible circuit board after connection are connected. Is left in a high-temperature and high-humidity atmosphere (for example, when a reliability test is performed in an atmosphere of 80 ° C. and 90% RH), as shown in FIG. 5, the terminals of the liquid crystal panel and the flexible circuit board There is a problem that the base film 42 made of polyimide or the like of the flexible circuit board 30 is floated (peeled) 44 at both ends of the electrode terminal 40 of the flexible circuit board 30 at the connection portion with the terminal portion.

  The main cause of the floating of the base film of the flexible circuit board when the liquid crystal panel and the flexible circuit board after connection are left in a high-temperature and high-humidity atmosphere is considered to be springback of the base film of the flexible circuit board. It is done. As shown in FIG. 6, by leaving the connected liquid crystal panel 26 and flexible circuit board 30 in a high temperature and high humidity atmosphere, the ultraviolet curable resin in the connecting material 34 and the liquid crystal panel 26 or flexible circuit board 30 are left. Adhesive strength at the interface becomes weaker. At that time, the stress which tries to perform the springback of the base film 42 of the flexible circuit board 30 sunk between the adjacent electrode terminals 40 of the flexible circuit board 30 is released, and the floating occurs. That is, when the liquid crystal panel 26 and the flexible circuit board 30 are connected, the ultraviolet curable resin is cured in a state in which the base film 42 of the flexible circuit board 30 is pushed between the adjacent electrode terminals 40 of the flexible circuit board 30. A stress for springback remains on the base film 42 of the flexible circuit board 30, and this residual stress is released for the reason described above. In FIG. 6, reference numeral 43 denotes an electrode terminal of the liquid crystal panel 26.

  Therefore, the reason why the base film of the flexible circuit board is lifted is that the adhesive force between the ultraviolet curable resin and the liquid crystal panel 26 or the ultraviolet curable resin and the liquid crystal panel 30 is smaller than the force for springback.

  Therefore, in order to strengthen the adhesive force between the ultraviolet curable resin and the liquid crystal panel or the flexible circuit board, conventionally, an aging process for holding the connected display panel and flexible circuit board at a temperature of 95 ° C. for 90 minutes is performed. By performing this aging process, even if the display panel and flexible circuit board are left in a high-temperature and high-humidity atmosphere after the aging process, the adhesive force between the UV curable resin and the liquid crystal panel or flexible circuit board has already been strengthened. No floating of the base film of the flexible circuit board occurs.

  However, in the connection process between the conventional display panel and the flexible circuit board described above, since the aging process is performed, the load of the connection process increases, and as a result, the manufacturing cost of the liquid crystal display device increases. It was.

  The present invention has been made in view of the above-described circumstances, and electrically connects the terminal portion of the display panel and the terminal portion of the flexible circuit board using a connecting material obtained by mixing conductive particles in an ultraviolet curable resin. In doing so, it is possible to prevent the occurrence of floating of the base film of the flexible circuit board when the display panel and the flexible circuit board after connection are left in a high-temperature and high-humidity atmosphere without performing an aging process after connection. It is an object of the present invention to provide a connection method and a connection device between a panel and a flexible circuit board.

  In order to achieve the above object, the present invention provides a connecting material obtained by mixing conductive particles in an ultraviolet curable resin between a terminal portion of a display panel and a terminal portion of a flexible circuit board. The display panel is formed by irradiating the connection material with ultraviolet rays in a state where pressure is applied to the terminal portion, the connection material and the terminal portion of the display panel by a pressure member to cure the ultraviolet curable resin in the connection material. In connecting the terminal portion of the flexible circuit board and the terminal portion of the flexible circuit board by the connecting material, the pressure member is provided with heating means, and the terminal of the flexible circuit board is provided by the heating means when the connecting material is irradiated with ultraviolet rays. And a connecting method between the display panel and the flexible circuit board, wherein the connecting member and the connecting material are heated.

  Further, the present invention provides a connecting material comprising a pressure member and an ultraviolet irradiation means, wherein a conductive particle is mixed with an ultraviolet curable resin between a terminal portion of a display panel and a terminal portion of a flexible circuit board. The connecting material is disposed by irradiating the connecting material with ultraviolet rays by the ultraviolet irradiating means in a state where pressure is applied to the terminal portion of the flexible circuit board, the connecting material and the terminal portion of the display panel by the pressing member. A device for connecting the terminal portion of the display panel and the terminal portion of the flexible circuit board by the connecting material by curing the ultraviolet curable resin therein, and the ultraviolet light applied to the connecting material on the pressure member A device for connecting a display panel and a flexible circuit board, characterized in that a heating means for heating the terminal part of the flexible circuit board and the connecting material at the time of irradiation is provided. To provide.

  In the present invention, the connecting portion is heated by heating means provided on the pressure member during ultraviolet irradiation, thereby increasing the reaction efficiency of the connecting portion, thereby improving the adhesive force of the ultraviolet curable resin, and the flexible circuit after connection. It is possible to avoid losing the stress of the spring back remaining on the base film of the substrate. Therefore, according to the present invention, the interfacial adhesive force between the ultraviolet curable resin, the liquid crystal panel, and the flexible circuit board is improved, and the occurrence of the floating of the base film of the flexible circuit board when left in a high temperature and high humidity atmosphere is prevented. be able to.

  In the present invention, it is appropriate to heat the terminal portion and the connecting material of the flexible circuit board by the heating means after a predetermined time has elapsed since the start of the ultraviolet irradiation. That is, by performing heating in the middle of ultraviolet irradiation, the initial reaction of the ultraviolet curable resin can be moderated and shrinkage of the ultraviolet curable resin during curing can be reduced. On the other hand, if heating is started at the same time as the start of UV irradiation, the UV curable resin reacts and cures rapidly due to UV light and heating, causing large shrinkage. As a result, the flexible circuit board when left in a high temperature and high humidity atmosphere The base film tends to float.

  In the present invention, the heating temperature of the terminal part of the flexible circuit board by the heating means or the heating temperature of the terminal part of the flexible circuit board and the connecting material is not particularly limited, but it is usually preferable to heat to 50 to 100 ° C. is there.

  In the present invention, the type of the heating means can be selected as appropriate, but a pulse heater is particularly preferable in that high-speed temperature rise and high-speed cooling are possible.

  According to the present invention, it is possible to prevent the base film of the flexible circuit board from being lifted when the connected display panel and flexible circuit board are left in a high-temperature and high-humidity atmosphere without performing an aging process.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples. For example, in addition to a liquid crystal panel as a display panel, an organic EL panel, a plasma display panel, and the like can be exemplified. FIG. 1 and FIG. 2 show an embodiment of a connection device between a liquid crystal panel and a flexible circuit board according to the present invention. FIG. 1 is a schematic view showing a state where a pressure bar is raised, and FIG. It is the schematic which shows the state which lowered | hung the bar. 1 and FIG. 2, the same reference numerals are given to the same components as those in FIG. 3 and FIG.

  In the connection device of this example, a pulse heater 50 is attached to the tip of a pressure bar (pressure member) 24 as a heating means, and the pulse heater 50 is flexible when the ultraviolet irradiation means 18 irradiates the connection material 34 with ultraviolet rays. The terminal portion 32 and the connecting member 34 of the circuit board 30 are heated.

  The material of the pressure bar 24 is not limited, but is preferably formed of a heat resistant material such as metal or ceramics. The flexible circuit board 30 includes a flexible printed circuit board (FPC) in which a wiring pattern is formed on a flexible film substrate, and a COF (Chip) in which a printed wiring is applied to a flexible insulating film and an LSI is mounted thereon. On Film), and TPC (Tape Carrier Package) in which a driving circuit is mounted on a tape.

  When the terminal unit 28 of the liquid crystal panel 26 and the terminal unit 32 of the flexible circuit board 30 are connected using the connection device of this example, conductive particles are mixed with ultraviolet curable resin on the surface of the terminal unit 28 of the liquid crystal panel 26. The connecting member 34 is laminated by coating, printing, or the like. Further, the liquid crystal panel 26 is placed on the liquid crystal panel support 10, the terminal portion 28 of the liquid crystal panel 26 is disposed on the terminal portion support 14, and the flexible circuit board support 12 is placed on the terminal portion 28 of the liquid crystal panel 26. The terminal portions 32 of the flexible circuit board 30 placed thereon are overlaid. The connection material 34 may be laminated before or after the liquid crystal panel 26 is placed on the liquid crystal panel support 10. Further, the liquid crystal panel 26 and the flexible circuit board 30 temporarily connected by the connecting material 34 may be placed on the liquid crystal panel support base 10, the flexible circuit board support base 12, and the terminal portion support base 14.

  Thereafter, as shown in FIG. 2, the pressure bar 24 is lowered, and the front surface pressing surface 25 presses the portion of the surface of the flexible circuit board 30 (the surface on which the electrode terminals are not formed) superimposed on the liquid crystal panel 26. Then, pressure is applied to the terminal portions 32 of the flexible circuit board 30, the connecting material 34, and the terminal portions 28 of the liquid crystal panel 26, and these are crimped. Further, in this state, the ultraviolet light 21 is irradiated to the connecting material 34 by the ultraviolet irradiation means 18.

  Next, after a predetermined time, for example, 10 seconds elapses after the ultraviolet irradiation by the ultraviolet irradiation means 18 is started, the pulse heater 50 is turned on, and the terminal portion 32 and the connecting member 34 of the flexible circuit board 30 are turned on by the pulse heater 50. Is heated for 20 seconds, for example. In this way, after a predetermined time has elapsed from the start of the ultraviolet irradiation, the ultraviolet irradiation and the heating are simultaneously performed to reduce the stress applied to the base film of the flexible circuit board 30 when connected to the liquid crystal panel 26, and in the connecting material 34 In a state in which the adhesive strength of the ultraviolet curable resin is improved, both terminal portions 28 and 32 are electrically connected by the connecting material 34, whereby the liquid crystal panel 26 and the flexible circuit board 30 after the connection are placed in a high-temperature and high-humidity atmosphere. This prevents the base film of the flexible circuit board 30 from being lifted when left unattended.

In this example, the UV irradiation amount, the UV irradiation timing, the heating temperature, and the heating timing can be set as appropriate. For example, the pressure bar 24 is lowered and the flexible circuit board 30, the connecting material 34, and the liquid crystal panel 26. Then, ultraviolet irradiation is started at an ultraviolet irradiation amount of 2000 mj / cm ² , and the pulse heater 50 is turned on 10 seconds after the ultraviolet irradiation is started, and the terminal portion 32 and the connecting material 34 of the flexible circuit board 30 are turned on. Can be heated at 70 ° C. for 20 seconds, and ultraviolet irradiation and heating are simultaneously stopped 30 seconds after the start of ultraviolet irradiation. In this case, the heating was started 10 seconds after the start of UV irradiation because the initial reaction of the UV curable resin progressed 10 seconds after the start of UV irradiation and the minimum adhesion between the liquid crystal panel and the flexible circuit board was obtained. Heating is started when this state is reached.

  When the liquid crystal panel and the flexible circuit board connected as described above were left in a high-temperature and high-humidity atmosphere at 80 ° C. and 90% RH, the base film of the flexible circuit board did not float.

1 is a schematic view showing a state where a pressure bar is raised, showing an embodiment of a connection device between a display panel and a flexible circuit board according to the present invention. It is the schematic which shows the state which lowered | hung the pressure bar of the connection apparatus of FIG. It is the schematic which shows an example of the connection apparatus of the conventional display panel and a flexible circuit board, and shows the state which raised the pressurization bar. It is the schematic which shows the state which lowered | hung the pressure bar of the connection apparatus of FIG. It is explanatory drawing which shows the state which the float produced in the base film of the flexible circuit board. It is explanatory drawing which shows the cause which a float arises in the base film of a flexible circuit board.

Explanation of symbols

18 UV irradiation means 24 Pressurization bar 26 Display panel 28 Terminal part 30 Flexible circuit board 32 Terminal part 34 Connection material 50 Heating means (pulse heater)

Claims (4)

  A connecting material obtained by mixing conductive particles in an ultraviolet curable resin is disposed between the terminal portion of the display panel and the terminal portion of the flexible circuit board, and the terminal portion of the flexible circuit board, the connecting material, and the display panel The terminal portion of the display panel and the terminal portion of the flexible circuit board are formed by irradiating the connecting material with ultraviolet rays while applying pressure to the terminal portion with a pressure member to cure the ultraviolet curable resin in the connecting material. When the connecting member is connected with the connecting member, the pressure member is provided with a heating unit, and the terminal unit of the flexible circuit board and the connecting member are heated by the heating unit when the connecting member is irradiated with ultraviolet rays. A method of connecting the display panel and the flexible circuit board.   The method for connecting the display panel and the flexible circuit board according to claim 1, wherein the terminal portion of the flexible circuit board is heated by the heating means after a predetermined time has elapsed since the start of the ultraviolet irradiation.   The flexible circuit includes a pressing member and an ultraviolet irradiation means, and a connecting material obtained by mixing conductive particles in an ultraviolet curable resin is disposed between the terminal portion of the display panel and the terminal portion of the flexible circuit board. An ultraviolet curable resin in the connection material is obtained by irradiating the connection material with ultraviolet rays by the ultraviolet irradiation means in a state where pressure is applied to the terminal portion of the substrate, the connection material and the terminal portion of the display panel by the pressure member. A device for connecting the terminal portion of the display panel and the terminal portion of the flexible circuit board by the connecting material by curing, wherein the flexible circuit board is applied to the pressure member when the connecting material is irradiated with ultraviolet rays. A connecting device between a display panel and a flexible circuit board, wherein a heating means for heating the terminal portion and the connecting material is provided. The connection device between the display panel and the flexible circuit board according to claim 3, wherein a terminal portion of the flexible circuit board is heated by the heating means after a predetermined time has elapsed since the start of the ultraviolet irradiation.

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