JP5535707B2 - Display device and display device connection status inspection method - Google Patents

Description

  The present invention relates to a display device in which a display panel and a wiring substrate are electrically connected by a flexible wiring substrate, and a method for inspecting a connection state of the display device.

  Display devices include liquid crystal display devices, organic electroluminescence (EL) display devices, inorganic EL display devices, plasma display devices, electrophoretic display devices, and field emission display (FED) devices. Various types of devices such as light emitting diode array display devices are known.

  Taking these liquid crystal display devices as an example, these display devices include an array substrate provided with pixel electrodes and the like, and a color filter substrate disposed so as to face the substrate (see Patent Document 1 below). ). The array substrate is formed to be larger than the color filter substrate when viewed from the front of the display surface, and this one end surface is covered with a resist material for inputting a drive signal to each pixel. A plurality of routing wirings, an IC chip to which the routing wirings are connected, a plurality of wirings electrically connected to the IC chip and having a surface coated with a resist material, and the plurality of wirings. A plurality of exposed connection terminals are provided as connected input terminals. The plurality of connection terminals are formed on at least one side of the peripheral edge of the array substrate.

  Further, in the liquid crystal display device, a wiring board is used separately from the array substrate in order to supply driving signals to these connection terminals. However, a plurality of exposed terminals as output terminals are also exposed on the periphery of the wiring board. Connection terminals are provided. A flexible wiring board is used to electrically connect the array board and the wiring board. The input terminal and the wiring terminal of the array board are connected to the input terminal and the output terminal of the flexible wiring board. The same number of exposed connection terminals as the electrode terminals are provided. Thus, the array substrate and the wiring substrate are electrically connected via the flexible wiring substrate, and an image signal displayed on the liquid crystal display device is input to the IC chip on the array substrate.

  When connecting the connection terminals of the flexible wiring board to the connection terminals of the array board and the wiring board, there is a difference between the connection terminals of the array board and the wiring board and the connection terminals of the flexible wiring board. They are connected by interposing a isotropic conductive film and heat-pressing the substrates together (see Patent Document 2 below). When an anisotropic conductive film is used, electrical connection between a plurality of terminals formed on the circuit board and the flexible wiring board can be easily performed by one thermocompression bonding as compared with the case of solder connection. In addition, there is an advantage that flexibility of connection portions and relaxation of thermal stress can be achieved.

  At this time, what is important is the alignment between the connection ends of the array substrate and the wiring substrate and the connection terminals of the flexible wiring substrate. Since the connection terminals of these substrates are originally arranged in the same manner, it seems that the alignment of each of these connection terminals can be performed automatically and accurately mechanically. However, in recent high-definition display devices, the connection terminals of the array substrate, the wiring substrate, and the connection terminal of the flexible wiring substrate are both thin and many in number, the pitch between the terminals is narrow, and there are variations in manufacturing. Thus, a short circuit occurs between adjacent terminals due to a slight inclination or misalignment.

  Therefore, in the conventional display device, for example, as shown in Patent Document 3 below, a flexible wiring board is provided by providing an electrical resistance test terminal on the flexible wiring board and measuring the resistance of the electrical test terminal in the mounted state. The quality of the connection state between the circuit board and the wiring board is determined. Here, a method for inspecting the connection status of the display device disclosed in Patent Document 3 below will be described with reference to FIG. 5 is an exploded view of the main part of the display device 50 disclosed in Patent Document 3 below.

  The display device 50 includes a liquid crystal display panel 51, a flexible wiring board 52, and a wiring board 53. The flexible wiring board 52 is formed with a first pad 55 for electric resistance inspection connected to the first inspection terminals 54a and 54b. On the wiring board 53, second pads 57a and 57b for electric resistance inspection connected to the second inspection terminals 56a and 56b, respectively, are formed. That is, only the first inspection terminals 54a and 54b are short-circuited by the first pad 55, but the second inspection terminals 56a and 56b are independently second resistance inspection second pads 57a and 57b, respectively. It is in a connected state.

  In the mounted body, the liquid crystal display panel 51 and the flexible wiring board 52 and the flexible wiring board 52 and the wiring board 53 are electrically connected by thermocompression bonding with an anisotropic conductive film, and the first inspection terminals 54a and 54b. Are electrically connected to the second inspection terminals 56a and 56b, respectively. Therefore, the first inspection terminals 54a and 54b and the second inspection terminals 56a and 56b are electrically connected, and a probe is brought into contact with each pad to measure the electrical resistance value of the connection portion. The quality of the connection state between the flexible wiring board 52 and the wiring board 53 is judged.

JP 2008-233727 A Japanese Patent Laid-Open No. 08-007957 Japanese Patent Laid-Open No. 08-008023

  In the method for inspecting the connection state of the display device disclosed in Patent Document 3, the electrical resistance between the first pad 55 and the second pad 57a and the electrical resistance between the first pad 55 and the second pad 57b are disclosed. The resistance and the electrical resistance between the second pads 57a and 57b are measured, and compared with the electrical resistance value of a good product obtained in advance, the quality of the connection state between the flexible wiring board 52 and the wiring board 53 is determined. Will be able to. In this case, it is possible to determine whether the connection state between the liquid crystal display panel 51 and the flexible wiring board 52 is good or not by providing inspection terminals on the liquid crystal display panel 51 as appropriate. Then, according to the method for inspecting the connection state of the display device disclosed in Patent Document 3, it can be used for monitoring of characteristic evaluation at the time of occurrence of a problem or until commercialization.

  In the display device method disclosed in the above-mentioned Patent Document 3, in order to confirm the electrical connection state with the electrical connection resistance value after thermocompression bonding, a test pad in which the wiring is folded inside is provided on the flexible wiring board. Although provided, the surface of the test pad had no protective film or the like to contact the probe, and the conductor remained exposed. Therefore, the display device disclosed in Patent Document 3 may cause a short circuit when any conductive member comes into contact with the test pad during manufacture or use, and the test pad may be damaged by moisture or the like. There was also a risk of corrosion.

  As a result of various studies to solve the problems of the prior art as described above, the inventors do not necessarily need to inspect the connection state in all display devices, and the occurrence of defects has been recognized. In this case, since the connection state may be inspected, it was found that it is not necessary to leave the surface of the test pad exposed, and the present invention has been completed. That is, an object of the present invention is to provide a display device and a display device connection state inspection method that are less likely to cause a short-circuit failure due to a test pad during manufacture or use and that are less likely to cause corrosion of the test pad.

  In order to achieve the above object, in the display device of the present invention, the electrode terminal of the wiring board and the input terminal of the flexible wiring board are electrically connected, and the output terminal of the flexible wiring board and the input of the display panel are connected. The display device is electrically connected to a terminal, and an electric signal from the wiring board is input to the display panel via the flexible wiring board, and the flexible wiring board includes the wiring The electrical connection state between the electrode terminal of the substrate and the input terminal of the flexible wiring substrate and the electrical connection state between the output terminal of the flexible wiring substrate and the input terminal of the display panel are measured. A plurality of electrical resistance measurement wirings are provided, and each of the plurality of electrical resistance measurement wirings is provided with an electrical resistance measurement pad covered with an insulating film.

  In the display device of the present invention, the wiring board and the display panel are connected by a flexible wiring board, and the flexible wiring board includes an electrode terminal of the wiring board and an input terminal of the flexible wiring board. A plurality of electrical resistance measurement wirings are provided for measuring the electrical connection state between and the electrical connection state between the output terminal of the flexible wiring board and the input terminal of the display panel; The electrical resistance measurement wiring is provided with an electrical resistance measurement pad covered with an insulating film. Therefore, according to the display device of the present invention, since the test pad is not exposed, there is a display device that is unlikely to cause a short-circuit failure due to the test pad during manufacturing or use, and that is less susceptible to corrosion of the test pad. can get.

  Then, in the display device of the present invention, when it is recognized that the connection state needs to be inspected when the occurrence of a defect or the like is recognized, the insulating film on the surface of the test pad is peeled to expose the test pad. From this, the electrical resistance can be measured. In addition, since the display device that has measured the electrical resistance has some trouble, it may be appropriately repaired or removed from the production line as a defective product.

  In addition, as a display panel which can be used for the display device of the present invention, a liquid crystal display panel, an organic EL display panel, an inorganic EL display panel, a plasma display panel, an electrophoretic display panel, an FED display panel, a light emitting diode array display panel, etc. The invention can be applied to a conventionally known electro-optical display panel.

  In the display device of the present invention, a plurality of electrode terminals of the wiring board are short-circuited to be a wiring board-side electrical resistance measurement terminal, and a plurality of input terminals of the display panel are short-circuited to each other. The plurality of electrical resistance measurement wirings are connected to the wiring board side electrical resistance measurement terminals, and the output terminals are respectively connected to the array substrate side electrical resistance measurement terminals. It is desirable to be connected to the board-side electrical resistance measurement terminal.

  In the display device of the present invention, a plurality of electrode terminals of the wiring board are short-circuited to be a wiring board-side electrical resistance measurement terminal, and a plurality of input terminals of the display panel are short-circuited to each other. Side electrical resistance measurement terminal. With such a configuration, the plurality of electrical resistance measurement wirings formed on the flexible wiring board are folded back via the wiring board side electrical resistance measurement terminal and the array board side electrical resistance measurement terminal, respectively. It becomes. Therefore, according to the display device of the present invention, by measuring the electrical resistance between the electrical resistance measurement pads formed on the multiple electrical resistance measurement wirings, the electrode terminal of the wiring board and the flexible wiring board It becomes possible to measure the electrical connection state between the input terminals and the connection state between the output terminals of the flexible wiring board and the input terminals of the display panel.

  In the display device of the present invention, it is preferable that an electric resistance measurement pad not covered with the insulating film is simultaneously formed on the flexible wiring board.

  If the electrical resistance measurement pad not covered with an insulating film is also formed on the flexible wiring board, the characteristics of the display device can be appropriately measured to maintain the quality of the display device, even if no malfunction occurs. To be able to help.

  In the display device of the present invention, the electrical resistance measurement pad may be formed in the middle of the electrical resistance measurement wiring.

  If the electrical resistance measurement pad is formed in the middle of the electrical resistance measurement wiring, simply measuring the electrical resistance between the electrical resistance measurement pads, the flexible wiring board, the electrode terminals of the wiring board, and the display panel It becomes possible to simultaneously determine whether the connection state with the input terminal is good or bad.

  In the display device of the present invention, the electrical resistance measurement pad may be provided at each end of the plurality of electrical resistance measurement wirings.

  If the electrical resistance measurement pad is provided at the end of the electrical resistance measurement wiring, it is only necessary to measure the electrical resistance between the electrical resistance measurement pads formed at this termination once and then connect the flexible wiring board and the wiring. It is possible to determine whether the connection state between the electrode terminal of the substrate or the input terminal of the display panel is good.

  In the display device of the present invention, the flexible wiring board can be any of a flexible printed wiring board, a tape carrier package, and a chip on film.

  A flexible printed wiring (FPC) substrate, a tape carrier package (TCP), and a chip-on-film (COF) are commonly used as flexible wiring substrates for display devices. It is applicable.

In the display device according to the aspect of the invention, the electrical resistance measurement pad is formed in an island shape in a state where the electrical resistance measurement pad is electrically insulated from the other wiring. The resistance measurement wiring may be connected to the electrical resistance measurement pad through a through hole formed in the flexible wiring board.

Wide wirings such as shield wiring, common wiring, and ground wiring exist on the flexible wiring board. An electrical resistance measurement pad is formed in an island shape in such a wide wiring in a state of being electrically insulated from the wiring, and the electrical resistance measurement wiring is formed in a flexible wiring board. If it is connected to the electrical resistance measurement pad via the wiring, it is not necessary to provide a separate space for forming the electrical resistance measurement pad, so that the space of the flexible wiring board can be used effectively. become.

  In the display device of the present invention, the electrical connection between the electrode terminal of the wiring board and the input terminal of the flexible wiring board, and the output terminal of the flexible wiring board and the input terminal of the display panel It is preferable that the electrical connection is made through an anisotropic conductive film.

  An anisotropic conductive film is used for the electrical connection between the electrode terminal of the wiring board and the input terminal of the flexible wiring board and the electrical connection between the output terminal of the flexible wiring board and the input terminal of the display panel. If it does, the short circuit between adjacent terminals will be suppressed, and since many terminals will be able to be correctly connected by one press bonding, manufacturing efficiency will improve.

  Furthermore, in order to achieve the above object, the display device connection state inspection method of the present invention is the display device connection state inspection method according to any one of the above, and is formed on the surface of the electrical resistance measurement pad. An electrical connection state between the electrode terminal of the wiring board and the input terminal of the flexible wiring board by peeling off the insulating film and contacting the electrical resistance measuring probe to the exposed surface of the electrical resistance measuring pad And inspecting an electrical connection state between the output terminal of the flexible wiring board and the input terminal of the display panel.

  According to the connection state inspection method for the display device of the present invention, the connection state inspection method can achieve the effects of the invention of the display device as described above.

FIG. 3 is a schematic plan view showing a connection state between the circuit board and the wiring board and the flexible wiring board according to the first embodiment. 2A is a schematic cross-sectional view taken along line IIA-IIA in FIG. 1, and FIG. 2B is a schematic cross-sectional view taken along line IIB-IIB in FIG. FIG. 3A is a main part plan view of a flexible wiring board according to a first modification, and FIG. 3B is a main part plan view of a flexible wiring board according to a second modification. It is a schematic plan view which shows the connection state of the circuit board which concerns on Embodiment 2, a wiring board, and a flexible wiring board. It is an exploded view of the principal part of the conventional display apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiment described below shows an example in which the invention is applied to a liquid crystal display panel and a wiring substrate of the liquid crystal display panel as an example of a display device in order to embody the technical idea of the present invention. Is not intended to be specified for the liquid crystal display panel or the wiring board of the liquid crystal display panel, and other embodiments included in the scope of the claims are equally applicable.

[Embodiment 1]
First, a liquid crystal display device 10A as a display device according to the first embodiment will be described with reference to FIGS. FIG. 1 is a schematic plan view showing a connection state between the circuit board and the wiring board and the flexible wiring board according to the first embodiment. 2A is a schematic cross-sectional view taken along line IIA-IIA in FIG. 1, and FIG. 2B is a schematic cross-sectional view taken along line IIB-IIB in FIG. In FIG. 1, a flexible printed wiring board (hereinafter referred to as “FPC board”) is seen through.

  As shown in FIG. 1, a liquid crystal display device 10 </ b> A includes a liquid crystal display panel 11, an FPC board 12 as a flexible wiring board connected to the liquid crystal display panel 11, and a wiring board also connected to the FPC board 12. 13.

  The liquid crystal display panel 11 includes a color filter substrate (not shown) and an array substrate 15 formed so that one end surface projects from the display surface side of the color filter substrate. A plurality of routing lines 16 covered with a resist material for inputting a drive signal to each pixel in the display area, and an IC chip 17 to which these routing lines 16 are connected, are arranged on one end face of the array substrate 15 protruding. A plurality of connection wires 19 electrically connected to the IC chip 17 and a plurality of exposed input terminals 20 are provided.

  The terminal region 21 in which the plurality of input terminals 20 are formed is aligned on one side of the array substrate 15, for example. Further, all the routing wirings 16 and connection wirings 19 of the array substrate 15 are covered with a resist material 18 and insulated from each other.

  The input terminals 20 of the array substrate 15 are all formed with the same width and the same pitch, and at least two on one side are the electrical resistance measurement terminals 20a and 20b. FIG. 1 shows an example in which a total of four electrical resistance measurement terminals 20a and 20b are formed at both ends of the input terminal 20, respectively. These array substrate side electric resistance measurement terminals 20a and 20b are short-circuited to each other by a short-circuit portion 20c on the array substrate 15 side.

  In addition, peripheral circuits (not shown) for generating various signals such as image signals and clock signals output to the liquid crystal display panel 11 are formed on the wiring board 13, and a plurality of electrode terminals 22 are provided on one side thereof. Arranged terminal regions 23 are formed. The electrode terminals 22 of the wiring board 13 are all formed with the same width and the same pitch, and at least two on one side are the wiring board side electric resistance measurement terminals 22a and 22b. FIG. 1 shows an example in which a total of four electrical resistance measurement terminals 20a and 20b are formed at both ends of the wiring board 13, respectively. These wiring board side electric resistance measurement terminals 22a and 22b are short-circuited to each other by a short-circuit portion 22c on the wiring board 13 side.

  The input terminals 20 in the terminal area 21 of the array substrate 15 and the electrode terminals 22 in the terminal area 23 of the wiring board 13 are electrically connected to each other by the FPC board 12. The FPC board 12 has a plurality of output terminals 25 for electrically connecting to input terminals 20 formed in the terminal area 21 of the array board 15 at one end of a flexible board 24 (see FIG. 2). A plurality of input terminals 26 are arranged at the other end for electrical connection with the electrode terminals 22 formed in the terminal region 23 of the wiring board 13. The plurality of input terminals 26 on one end side of the FPC board 12 and the plurality of output terminals 25 on the other end side are electrically connected to each other by connection wirings 27, and the surface of the connection wiring 27 is made of a resist material or insulating material. It is covered and electrically insulated by a translucent thin film 28 (see FIG. 2) made of a material.

  The array substrate-side electrical resistance measurement terminals 20a and 20b are respectively connected to the first and second electrical resistance measurement pads 29a and 29b by the first and second electrical resistance measurement wires 27a and 27b formed on the FPC board 12, respectively. It is connected. The wiring board side electric resistance measurement terminals 22a and 22b are connected to the third and fourth electric resistance measurement pads 29c and 29d by the third and fourth electric resistance measurement wirings 27c and 27d formed on the FPC board 12, respectively. It is connected. The first to fourth electric resistance measuring pads 29a to 29d are both electrically insulated by being covered with a translucent thin film 28 made of an insulating material.

  A fixed state between the input terminal 20 of the array substrate 15 and the output terminal 25 of the FPC substrate 12 will be described with reference to FIG. As shown in FIG. 2A, an anisotropic conductive film 30 is placed on the array substrate-side electrical resistance measurement terminal 20a (20b) of the array substrate 15. Thus, the array substrate-side electrical resistance measurement terminal 20a (20b) of the array substrate 15 is electrically connected to the output terminal 25 of the FPC substrate 12, respectively. The surface of the array substrate-side electrical resistance measurement terminal 20a (20b) is covered with the output terminal 25 of the FPC board 12 and the flexible board 24.

  As shown in FIG. 2B, an anisotropic conductive film 30 is also placed on the input terminal 20 of the array substrate 15, and the array substrate 15 is connected via the anisotropic conductive film 30. The input terminals 20 are electrically connected to the output terminals 25 of the FPC board 12, respectively. The surface of the input terminal 20 is covered with the output terminal 25 of the FPC board 12 and the flexible board 24 via the anisotropic conductive film 30.

  The anisotropic conductive film 30 is electrically connected by placing the anisotropic conductive film 30 on the input terminal 20 of the array substrate 15 and the array substrate side electric resistance measurement terminals 20a and 20b. This is performed by placing the output terminal 25 of the FPC board 12 on the surface of the conductive film 30 with accurate alignment and thermocompression bonding. Since an electrical connection method using such an anisotropic conductive film 30 is well known, description of the specific method is omitted. The electrical connection between the electrode terminal 22 of the wiring board 13 and the input terminal 26 of the FPC board 12 is such that the input terminal 20 of the array board 15 is electrically connected to the output terminal 25 of the FPC board 12. Since it is the same as that of a connection state, the detailed description is abbreviate | omitted.

  According to the liquid crystal display device 10A of Embodiment 1 having such a configuration, the first to fourth electric resistance measurement pads 29a to 29d are covered with the translucent thin film 28 made of an insulating material. Since it is not exposed, short circuit failure due to the first to fourth electric resistance measurement pads 29a to 29d hardly occurs at the time of manufacture or use, and the first to fourth electric resistance measurement pads 29a. A liquid crystal display device 10A with less risk of corrosion of -29d is obtained.

  Further, according to the liquid crystal display device 10A of the first embodiment, as shown in FIG. 1, the first electrical resistance measurement pad 29a of the FPC board 12 includes the electrical resistance measurement wiring 27a, the output terminal 25, and the anisotropic Conductive film 30 (see FIG. 2), array substrate side electrical resistance measurement terminal 20a, short-circuit portion 20c, array substrate side electrical resistance measurement terminal 20b, anisotropic conductive film 30, and second electrical resistance measurement wiring 27b. Then, it is electrically connected to the second electric resistance measurement pad 29b. The third electrical resistance measurement pad 29c includes the electrical resistance measurement wiring 27c, the input terminal 26, the anisotropic conductive film 30, the wiring board side electrical resistance measurement terminal 22a, the short circuit portion 22c, and the wiring board side electrical resistance. It is electrically connected to the fourth electrical resistance measurement pad 29d through the measurement terminal 22b, the anisotropic conductive film 30, and the fourth electrical resistance measurement wiring 27d.

  Therefore, the electrical connection state between the FPC board 12 and the array substrate 15 is determined by measuring the electrical resistance between the first electrical resistance measurement pad 29a and the second electrical resistance measurement pad 29b. Can be determined. Further, the electrical connection state between the FPC board 12 and the wiring board 13 is determined by measuring the electrical resistance between the third electrical resistance measurement pad 29c and the fourth electrical resistance measurement pad 29d. Can be determined. As described above, according to the liquid crystal display device 10A of the first embodiment, the quality of the electrical connection state between the FPC board 12 and the array board 15 and between the FPC board 12 and the wiring board 13 is individually determined. Will be able to.

  For this reason, in the case where some troubles are observed during manufacturing or testing, and it is recognized that the connection state between the FPC board 12 and the array board 15 and the wiring board 13 needs to be inspected, the second The electrical resistance can be measured by peeling off the insulating films on the surfaces of the first to fourth electric resistance measuring pads 29a to 29d to expose the first to fourth electric resistance measuring pads 29a to 29d. . In the liquid crystal display device 10A of the first embodiment, the electrical resistance between the first and second electrical resistance measurement pads 29a and 29b or the electrical resistance between the third and fourth electrical resistance measurement pads 29c and 29d is measured. It is possible to determine whether the electrical connection state between the FPC board 12 and the array board 15 or the wiring board 13 is good.

  The quality of the electrical connection state at this time can be easily discriminated by comparing data measured in advance with respect to a non-defective product. In addition, since the display device that has measured the electrical resistance has some trouble, it may be appropriately repaired or eliminated as a defective product.

[First Modification]
As the liquid crystal display device 10A of the first embodiment, the example in which the first to fourth electric resistance measurement pads 29a to 29d are provided at the end of the electric resistance measurement wiring is shown, but in the middle of the electric resistance measurement wiring. It may be formed. Here, as a first modification, only the first and second electric resistance measurement pads 29a and 29b are provided, and the quality of the electrical connection state between the FPC board 12 and the array board 15 or the wiring board 13 is determined. An example in which this can be done will be described with reference to FIG. 3 which is a plan view of the main part of the FPC board.

  The configuration of the liquid crystal display device of the first modified example is the same as the liquid crystal display device 10A of the first embodiment, only the arrangement of the first and second electric resistance measurement pads and the electric resistance measurement wiring arrangement of the FPC board 12. Are different from each other, and FIG. 1 and FIG. 2 are used as necessary, and a specific description thereof is omitted.

  In the liquid crystal display device of the first modification, the second electrical resistance measurement wiring 27b and the fourth electrical resistance measurement wiring 27d in the FPC board 12 of the first embodiment are directly connected to form an electrical resistance measurement wiring 27e. The third and fourth electric resistance measurement pads 29c and 29d are omitted.

  That is, in the liquid crystal display device of the first modification, the array substrate side electrical resistance measurement terminal 20b of the array substrate 15 is electrically connected to the wiring board side electrical resistance measurement terminal 22b of the wiring substrate 13 via the electrical resistance measurement wiring 27e. Connected. The array substrate-side electrical resistance measurement terminal 20a of the array substrate 15 is connected to the first electrical resistance measurement pad 29a via the first electrical resistance measurement wiring 27a. The measurement terminal 22a is connected to the second electrical resistance measurement pad 29b via the second electrical resistance measurement wiring 27b. Also in this case, the first and second electric resistance measurement pads 29a and 29b are covered with a translucent thin film 28 (see FIG. 2) made of an insulating material.

  In the liquid crystal display device of the first modified example having such a configuration, the first electrical resistance measurement pad 29a of the FPC board 12 includes the electrical resistance measurement wiring 27a, the output terminal 25, the anisotropic conductive film 30, and the array substrate. Side electrical resistance measurement terminal 20a, short circuit portion 20c, array substrate side electrical resistance measurement terminal 20b, anisotropic conductive film 30, electrical resistance measurement wiring 27e, input terminal 26, anisotropic conductive film 30, wiring board side Via the electrical resistance measurement terminal 22b, the short circuit portion 22c, the wiring board side electrical resistance measurement terminal 22a, the anisotropic conductive film 30, the input terminal 26, the anisotropic conductive film 30, and the second electrical resistance measurement wiring 27b. Thus, it is connected to the second electric resistance measurement pad 29b.

  Therefore, in the liquid crystal display device of the first modification, only the electrical resistance between the first and second electrical resistance measuring pads 29a and 29b is measured, and the space between the FPC board 12 and the array board 15 or the wiring board 13 is measured. The quality of the electrical connection state can be determined. In addition, the first and second electric resistance measurement pads 29a and 29b are covered with the semitransparent thin film 28 made of an insulating material and are not exposed, so that the first and second electric resistance measurement pads 29a and 29b are manufactured and used. Thus, a liquid crystal display panel is obtained in which short-circuit failure due to the second electrical resistance measurement pads 29a and 29b hardly occurs and the first and second electrical resistance measurement pads 29a and 29b are less likely to corrode.

  In the liquid crystal display device according to the first modification, the array substrate-side electrical resistance measurement terminal 20b of the array substrate 15 is connected to the wiring substrate-side electrical resistance measurement terminal 22b of the wiring substrate 13 via the electrical resistance measurement wiring 27e. Although an example of electrical connection has been shown, in such a configuration, an electrical connection state between the FPC board 12 and the array board 15 and an electrical connection between the FPC board 12 and the wiring board 13 are shown. It cannot be measured separately from the connection status. Therefore, a part of the electrical resistance measurement wiring 27e is used as the electrical resistance measurement pad 29e, and between this electrical resistance measurement pad 29e and the first electrical resistance measurement pad 29a or for the second electrical resistance measurement. By measuring the electrical resistance between the pads 29b, the electrical connection state between the FPC board 12 and the array board 15 and the electrical connection state between the FPC board 12 and the wiring board 13 are distinguished and measured. Will be able to.

  In the liquid crystal display device according to the first embodiment and the first modified example, an example in which the electrical resistance measurement pad formed on the FPC board 12 is covered with a translucent thin film made of an insulating material has been described. An electric resistance measurement pad that is not covered with an insulating material may be provided. In this way, if an electrical resistance measurement pad that is not covered with an insulating material is provided, the characteristics of the liquid crystal display device can be appropriately measured to help maintain the quality of the liquid crystal display device, even if there is no particular problem. Will be able to.

[Second Modification]
In the liquid crystal display device of the first embodiment and the first modified example, there is a sufficient space for forming the electrical resistance measurement pad on the FPC board 12, and other wirings are provided around the electrical resistance measurement pad. An example that does not exist. However, in a small liquid crystal display device, the width and length of the FPC board 12 are also small, so that there may be a case where there is not enough space for forming the electrical resistance measurement pads.

  On the other hand, the FPC board 12 includes a wide wiring such as a shield wiring, a common wiring, or a ground wiring. Therefore, as an example of a liquid crystal display device according to a second modification, an example in which an electrical resistance measurement pad is formed in a wide wiring will be described with reference to FIG. In FIG. 3B, only the portion where the first and second electric resistance measurement pads 29f and 29g are formed in the ground wiring 31 is shown.

  The configuration of the liquid crystal display device of the second modified example is different from that of the liquid crystal display device 10A of the first embodiment and the liquid crystal display device of the first modified example in the arrangement of the electrical resistance measurement pads 29f and 29g on the FPC board 12 and Since only the arrangement of the measurement wirings 27f and 27g is different, FIGS. 1, 2 and 3A are used as necessary, and the specific description thereof is omitted.

  In FIG. 3B, a wide ground wiring 31 is formed on one surface of the flexible substrate 24 (see FIG. 2) of the FPC substrate 12, and first and second electric resistances are formed on the other surface. An example in which measurement wirings 27f and 27g are formed is shown. In the ground wiring 31, first and second electric resistance measurement pads 29 f and 29 g are formed in an island shape in a state of being electrically insulated from the ground wiring 31. The first and second electrical resistance measurement pads 29f and 29g are electrically connected to the first and second electrical resistance measurement wirings 27f and 27g through the through holes 32 and 33, respectively.

  Also in this case, the first and second electric resistance measurement pads 29f and 29g are covered with a translucent thin film made of an insulating material. The connection state between the first and second electric resistance measurement wirings 27f and 27g and the array substrate side electric resistance measurement terminals 20a and 20b or the connection state between the wiring substrate side electric resistance measurement production regions 22a and 22b is as follows. Although not shown, this is the same as the case of the liquid crystal display device 10A of the first embodiment or the liquid crystal display device of the first modification.

  Therefore, in the liquid crystal display device of the second modification, only the electric resistance between the first and second electric resistance measurement pads 29f and 29g is measured, and the gap between the FPC board 12 and the array board 15 or the wiring board 13 is measured. The quality of the electrical connection state can be determined. In addition, the first and second electric resistance measurement pads 29f and 29g are covered with a translucent thin film made of an insulating material and are not exposed. A liquid crystal display panel is obtained in which the short circuit failure caused by the electrical resistance measurement pads 29f and 29g hardly occurs and the first and second electrical resistance measurement pads 29f and 29g are less likely to corrode.

  In addition, in the liquid crystal display device according to the second modified example, the first and second electric resistance measurement pads 29f and 29g are formed inside the ground wiring 31, so that the first and second electric resistance measurements are separately performed. There is no need to secure a space for forming the pads 29f and 29g. Therefore, the space of the flexible wiring board can be used effectively, and it can be easily adopted for a small liquid crystal display device.

[Embodiment 2]
In the liquid crystal display devices of the first embodiment, the first and second modified examples, the example in which the array substrate 15 and the wiring substrate 13 are connected by the FPC substrate as the flexible wiring substrate is shown. However, the present invention is not limited to this, and can be applied to an example using TCP or COF as a flexible wiring board. Note that both TCP and COF have a configuration in which a bare chip such as a driver IC is mounted on an FPC board, and are regarded as substantially the same. A plan view of the liquid crystal display device 10B of Embodiment 2 using such COF will be described with reference to FIG.

  As shown in FIG. 4, the liquid crystal display device 10 </ b> B according to the second embodiment includes a liquid crystal display panel 11, a COF 30 as a flexible wiring board connected to the liquid crystal display panel 11, and a wiring board connected to the COF 30. 13. The COF 30 is substantially different in configuration from the FPC board 12 in the liquid crystal display device 10A of Embodiment 1 except that the driver IC 17 is placed on the flexible board and the shape of the flexible board is different. Does not exist. Therefore, the same components as those of the liquid crystal display device 10A of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  Also in the liquid crystal display device 10B of the second embodiment, the first electrical resistance measurement pad 29a of the COF 30 is the electrical resistance measurement wiring 27a, the output terminal 25, the anisotropic conductive film 30, and the array substrate side electrical resistance measurement. It is electrically connected to the second electrical resistance measurement pad 29b through the terminal 20a, the short circuit portion 20c, the array substrate side electrical resistance measurement terminal 20b, the anisotropic conductive film 30, and the second electrical resistance measurement wiring 27b. ing. The third electrical resistance measurement pad 29c includes the electrical resistance measurement wiring 27c, the input terminal 26, the anisotropic conductive film 30, the wiring board side electrical resistance measurement terminal 22a, the short circuit portion 22c, and the wiring board side electrical resistance. It is electrically connected to the fourth electrical resistance measurement pad 29d through the measurement terminal 22b, the anisotropic conductive film 30, and the fourth electrical resistance measurement wiring 27d. Also in this case, the first to fourth electric resistance measurement pads 29a to 29b are covered with a translucent thin film 28 made of an insulating material.

  Therefore, the quality of the electrical connection state between the COF 30 and the array substrate 15 is determined by measuring the electrical resistance between the first electrical resistance measurement pad 29a and the second electrical resistance measurement pad 29b. Will be able to. Further, the quality of the electrical connection state between the COF 30 and the wiring board 13 is determined by measuring the electrical resistance between the third electrical resistance measurement pad 29c and the fourth electrical resistance measurement pad 29d. Will be able to. Thus, according to the liquid crystal display device 10B of the second embodiment, substantially the same effect as the liquid crystal display device 10A of the first embodiment can be obtained.

  In the above embodiments, the case of a liquid crystal display device has been described as an example of the display device. However, as a display panel that can be used for the display device of the present invention, an organic EL display panel, an inorganic EL display can be used in addition to the liquid crystal display panel. Conventionally known electro-optical display panels such as display panels, plasma display panels, electrophoretic display panels, FED display panels, and light-emitting diode array display panels are exemplified.

  DESCRIPTION OF SYMBOLS 10A, 10B ... Liquid crystal display device 11 ... Liquid crystal display panel 12 ... FPC board 13 ... Wiring board 15 ... Array board 16 ... Lead-out wiring 17 ... IC chip 18 ... Resist material 19 ... (Array board) connection wiring 20 ... Input terminal 20a , 20b ... Array substrate side electrical resistance measurement terminal 20c ... Short-circuit portion 21 ... (array substrate) terminal region 22 ... Electrode terminal 22a, 22b ... Wiring board side electrical resistance measurement terminal 22c ... Short-circuit portion 23 ... (flexibility) Terminal area 24 of substrate 24 ... Flexible substrate 25 ... Output terminal of flexible substrate 26 ... Input terminal of flexible substrate 27 ... Connection wiring 27a to 27g ... Electrical resistance measurement wiring 28 ... Translucent thin film 29a-29g ... Electric resistance measuring pad 30 ... Anisotropic conductive film 31 ... Ground wiring 32, 33 ... Through-ho Le

Claims (11)

The electrode terminal of the wiring board and the input terminal of the flexible wiring board are electrically connected, the output terminal of the flexible wiring board and the input terminal of the display panel are electrically connected, and A display device in which an electrical signal is input to the display panel via the flexible wiring board,
The flexible wiring board includes an electrical connection state between an electrode terminal of the wiring board and an input terminal of the flexible wiring board, and an output terminal of the flexible wiring board and an input terminal of the display panel. A plurality of electrical resistance measurement wirings are provided for measuring the electrical connection state between
The display device according to claim 1, wherein each of the plurality of electrical resistance measurement wirings is provided with an electrical resistance measurement pad covered with an insulating film. A plurality of electrode terminals of the wiring board are short-circuited to each other to be a wiring board-side electrical resistance measurement terminal,
A plurality of input terminals of the display panel are array substrate-side electrical resistance measurement terminals that are short-circuited to each other,
In the plurality of electrical resistance measurement wirings, the input terminal is connected to the wiring board side electrical resistance measurement terminal, and the output terminal is connected to the array board side electrical resistance measurement terminal. The display device according to claim 1.   The display device according to claim 1, wherein an electrical resistance measurement pad not covered with the insulating film is also formed on the flexible wiring board.   The display device according to claim 1, wherein the electrical resistance measurement pad is formed in the middle of the electrical resistance measurement wiring.   The display device according to claim 1, wherein each of the electrical resistance measurement pads is provided at an end of the plurality of electrical resistance measurement wirings. Said constant pads measuring electrical resistance, other said other wiring in the wiring are formed in an island shape in an electrically insulated state, the plurality of electrical resistance measuring wire, wherein the flexible The display device according to claim 4, wherein the display device is connected to the electric resistance measurement pad through a through hole formed in the wiring board. The flexible wiring board, a flexible printed wiring board, a display device of any crab according to claim 1, wherein is any one of a tape carrier package or a chip on film. The electrical connection between the electrode terminal of the wiring board and the input terminal of the flexible wiring board and the electrical connection between the output terminal of the flexible wiring board and the input terminal of the display panel are anisotropic. display device according crab of claims 1 to 7, characterized in that it is carried through the conductive film.   The connection state inspection method for a display device according to claim 1, wherein the insulating film formed on a surface of the electric resistance measurement pad is peeled off and exposed. An electrical resistance measuring probe is brought into contact with the surface of the wiring board to electrically connect the electrode terminal of the wiring board and the input terminal of the flexible wiring board, and the output terminal of the flexible wiring board and the input of the display panel A method for inspecting a connection state of a display device, wherein the state of electrical connection with a terminal is inspected. The electrode terminal of the wiring board and the input terminal of the flexible wiring board are electrically connected, the output terminal of the flexible wiring board and the input terminal of the display panel are electrically connected, and A display device in which an electrical signal is input to the display panel via the flexible wiring board,
The flexible wiring board is provided with a plurality of electrical resistance measurement wirings for measuring an electrical connection state between the electrode terminal of the wiring board and the input terminal of the flexible wiring board. And
The display device according to claim 1, wherein each of the plurality of electrical resistance measurement wirings is provided with an electrical resistance measurement pad covered with an insulating film. The electrode terminal of the wiring board and the input terminal of the flexible wiring board are electrically connected, the output terminal of the flexible wiring board and the input terminal of the display panel are electrically connected, and A display device in which an electrical signal is input to the display panel via the flexible wiring board,
The flexible wiring board is provided with a plurality of electrical resistance measurement wirings for measuring an electrical connection state between an output terminal of the flexible wiring board and an input terminal of the display panel. And
  The display device according to claim 1, wherein each of the plurality of electrical resistance measurement wirings is provided with an electrical resistance measurement pad covered with an insulating film.

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