JP2006237158A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent displacement in the connection between a high-density display panel with 40 μm pitches, or the like and a film substrate. <P>SOLUTION: A connection terminal is divided into two stages with two types of terminal widths, thick and thin. The first-stage and second-stage terminals of the display panel are allowed to be thick and thin, respectively, the first-stage and second-stage terminals of the corresponding film substrate are allowed to be thin and thick, respectively, and the thick and thin terminals are connected by an anisotropic conductive film, thus enlarging a displacement margin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mounting structure of a flexible substrate and a flat panel display such as a passive matrix liquid crystal panel, an active matrix liquid crystal panel, a plasma display, an organic EL display, an inorganic EL display, SED, or FED.

  A side view of a conventional STN liquid crystal display device is shown in FIG. The transparent substrate on which the segment electrode is formed and the transparent substrate on which the common electrode is formed are opposed to each other, and the terminal panel 8 is aligned with the display panel 7 holding the liquid crystal and the film substrate 9 on which the driver IC 10 is mounted. The structure is connected by an anisotropic conductive film. The screen is driven by applying a voltage to each electrode of the display panel 7 in a time-sharing manner. The segment signal and the common signal are different from each other, and the signal is applied by connecting the output electrode of the driver IC 10 for each electrode constituting the dot matrix. As shown in FIG. 7, the film substrate 9 has a driver IC 10 for outputting a segment signal and a common signal mounted on a polyimide film on which copper is patterned and tin-plated or gold-plated terminals are formed. An anisotropic conductive film 11 is connected to the terminal portion 8 of the panel 7. The anisotropic conductive film 11 is formed in a B-stage state in a film shape of about 15 μm by dispersing and blending conductive particles obtained by electroless plating of nickel and gold on an acrylic resin ball in an epoxy thermosetting adhesive. Has been. As shown in FIG. 9, the display panel 7 and the film substrate 9 are connected by temporarily attaching an anisotropic conductive film 11 on the terminal portion 8 of the display panel, and the terminal 6 of the film substrate 9 and the terminal 1 of the display panel 7. As shown in FIG. 10, they are aligned and temporarily attached, and are heat-pressed with a heating bar to crush the conductive particles to establish a connection and harden the adhesive to maintain the connection. As for the shape of the terminal, the electrode width and the space between the electrodes shown in FIG. 11 were arranged at equal intervals. By slightly increasing the width of the terminal 1 of the display panel 7 with respect to the width of the terminal 6 of the film substrate 9, a slight positional shift is absorbed. The deviation is required to be 10-15 μm or less with respect to the pitch direction, but it is rough at about 100 μm in the direction perpendicular to the pitch direction.

  If the number of pixels is 160 × 128 (RGB) dots, a total of 544 electrodes are connected by 384 segments and 160 commons, and if the display panel size is 1.8 inches, the connection pitch Became a 50 micron pitch. In the case of 50 micron pitch, the width of the terminal 1 of the display panel 7 is 25 μm and the width of the terminal 6 of the film substrate 9 is 18 μm. Due to the initial accumulated pitch variation of the film substrate 9, the positional deviation due to the apparatus mounting accuracy, and the variation in the elongation of the film substrate 9 due to the pressure bonding, ± 17 μm is achieved, and a stable connection can be achieved. Good connection means that conductive particles with a diameter of about 4 μm are crushed to about 1 μm, the number of conductive particles contributing to conduction is 5 or more, there is no short circuit, and the distance between adjacent electrodes is 1.5 particles or more. It is desirable that there be. Due to the temporary attachment position of the film substrate 9, the initial dimensions of the film substrate 9, and the elongation due to pressure bonding, the positional deviation between the terminals at both ends was particularly large. When the overlap between the electrodes of the display panel 7 and the film substrate 9 is reduced, the overlapping area of the electrodes is reduced as shown in FIG. 12, and there is no conductive particle contributing to the connection, or as shown in FIG. There may be a short circuit to the electrode. In particular, when the fine connection was made, a displacement due to the elongation of the film substrate 9 occurred together with the positional displacement. In such a case, a method of crimping using a terminal design in which the elongation amount of the film substrate 9 is corrected in advance is known (see, for example, Patent Document 1 and Patent Document 2).

In addition, since the distance between the film terminal 6 and the terminal 1 of the display panel is narrowed, the probability of occurrence of a short circuit due to foreign matter or the like is increased. In general, the basic measures are to clean the terminals before mounting and to prevent dust in clean rooms. There is a method in which the anisotropic conductive film 11 is pressure-bonded so as to form a staggered pattern (see, for example, Patent Document 3).
Japanese Patent Laid-Open No. 10-260421 (page 4, FIG. 1) Japanese Patent Laid-Open No. 2000-312070 (page 4, FIG. 1) Japanese Laid-Open Patent Publication No. 2000-347592 (Section 6, Fig. 2)

  However, with the higher definition of the panel, the pitch became narrower. In particular, when mounting at a pitch of 40 μm, (1) positional deviation occurs due to variations in initial dimensions of the film substrate, variations in elongation due to crimping, and variations in mounting accuracy, and short-circuits with adjacent terminals. (2) Existing equipment Therefore, it was necessary to introduce new high-precision equipment, and there was a problem that the processing cost was high. Accordingly, an object of the present invention is to provide an inexpensive display device that does not cause a short circuit even at a narrow pitch of 40 μm and can be produced with existing equipment.

  The present invention has been solved by devising the shapes of the display panel and the film substrate terminal. In the display device of the present invention, a plurality of terminals connected to the display panel and the film substrate are connected in two stages. Furthermore, there are two types of terminal widths for both the display panel and the film substrate. The two types of widths are almost the same for the display panel and the film substrate, and the terminal widths are unified for each stage. The width of the terminal connecting the panel and the film substrate is different between the display panel and the film substrate. Further, the terminal width of the display panel and the film substrate is wider at the terminal width of the second stage than the terminal width of the stage at the terminal tip side. Furthermore, the interval between the two-stage terminals is larger than the terminal pitch. That is, the terminals of the display panel and the film substrate are configured in two stages, and the electrodes also have two types of terminal widths: a thick electrode and a thin electrode. The first stage of the display panel is a repetition of a lead wire connected to the second stage terminal with a thick width electrode, and the second stage is a repetition of a narrow width electrode connected to the lead line without a terminal. The first stage of the film substrate is a repetition of a thin electrode and no electrode, and the second stage is a repetition of a lead electrode and a thick electrode connected to the first narrow electrode, a display panel and a film substrate. Is a configuration in which a thick electrode and a narrow electrode are connected to each other. At this time, the wide electrode width of the display panel, the wide electrode width of the film substrate, the thin electrode of the display panel, and the thin electrode of the film substrate do not need to have the same dimensions.

  According to the terminal shape of the present invention, it can be mounted with a positional accuracy equivalent to a conventional 55 μm pitch while being a 40 μm pitch. Therefore, it was possible to produce a product with sufficiently stable quality even when using conventional equipment.

  The display panel of the display device according to the present invention and the terminals of the film substrate are configured in two stages, and the electrodes are also configured with two types of terminal widths, a thick electrode and a thin electrode. The first stage of the display panel is a repetition of a lead line connected to a thick electrode and a second stage terminal. First, the line width of the lead line is preferably the line width of MIN in the process manufacturing capability. The space between the lead line and the thick electrode is set to the same value as the minimum space in the mounting process capability in the conventional structure. When the MIN line width of the film substrate is thicker, it may be matched with the MIN line width of the film substrate. The dimension remaining after subtracting these is defined as the width of the electrode having a large width.

  The terminal of the film substrate connected to the thick electrode of the first display panel is a thin electrode. When the positional deviation between the film substrate and the display panel is zero, the distance from the display panel lead line is The same value as the minimum value of the distance between the terminal of the film substrate and the terminal of the display panel next to it, which is possible in the mounting process capability in the conventional structure, and the remaining dimension is the width of the thin electrode of the film substrate To do. The electrode of the film substrate is not disposed in the portion located on the lead line of the display panel. The terminals on the second stage of the display panel are repeated with no electrodes and thin electrodes, and no terminals are arranged on the extension of the thick electrodes with the first stage. Next, an electrode having substantially the same width as that of the thin electrode on the first stage film substrate is arranged next to it and connected to the first stage lead-out electrode. The terminal on the second stage of the film substrate is a repetition of the lead-out electrode and the electrode having a large width. A routing electrode connected to the first-stage narrow electrode is disposed. The width of the lead-out electrode is preferably equal to or narrower than the lead-out electrode width of the display panel. The width of the adjacent thick electrode is set to be substantially the same as the width of the thick electrode of the first-stage display panel. The distance between the first stage terminals and the second stage terminals is preferably wide, and there is a relationship with the mounting accuracy of the mounting machine, and it is desirable that there is a margin of dimension more than the connection pitch.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a top view of terminals of a display panel according to the present invention. The display panel is a color STN display panel. A terminal 1 is formed on a glass substrate 2. The terminal 1 is made of ITO (Indium-Tin-Oxide), which is a transparent conductive film, and a substrate formed by sputtering is patterned by a photo method. Terminals to be connected to the display panel include a first-stage terminal 3 and a second-stage terminal 4.

  The first stage terminal 3 includes a 40 μm wide terminal and a 10 μm wide lead electrode, and the electrode spacing is 15 μm. The terminal 4 in the second stage is provided with a narrow terminal having a width of 23 μm on the extension of the routing electrode.

FIG. 2 is a perspective view of the terminals of the film substrate. A film substrate is formed by sputtering a chromium alloy and copper on a polyimide film 5 and further patterning the substrate by electrolytic plating of 8 microns, and patterning by a photo method, thereby forming the electroless tin-plated terminals 6.
Similarly, the terminals of the film substrate are formed in two stages. The first stage terminal 3 is a narrow terminal having a width of 23 μm. The second-stage terminal 4 is composed of a 10 μm-wide routing electrode connected to the first-stage narrow-width electrode and a 40-μm thick electrode.

  FIG. 3 is a perspective view showing a positional relationship when the film substrate and the terminal of the display panel are aligned and connected by an anisotropic conductive film. Here, the particles of the anisotropic conductive film are not shown. In the terminal 3 at the first stage, the thick electrode of the display panel and the thin electrode of the film substrate are connected. The terminals 4 at the second stage are connected by electrodes having a large width on the film substrate and electrodes having a small width on the display panel.

  FIG. 4 is a perspective view showing the positional relationship when the terminals of the film substrate and the terminals of the display panel are displaced by 20 μm. In this state, there is an interval until the thin electrode on the first stage terminal film substrate and the lead-out electrode on the display panel are short-circuited. Similarly, the distance between the lead electrode on the film substrate of the second stage terminal and the narrow electrode on the display panel is also not short-circuited. As the conductive particles of the anisotropic conductive film, particles having a diameter of 4 μm obtained by plating nickel and gold on an acrylic resin ball and particles formed by further forming a thermoplastic insulating film are used. In order to prevent short-circuiting when the beads are connected, dozens of percent of particles with insulating coating are mixed.

  As described above, the connection pattern of the present invention is a good product even if the pattern size is shifted by 40 μm or ± 20 μm. In the case of the conventional pattern shape, the margin is greatly expanded since the pitch is 40 μm up to ± 10 μm. Further, a deviation margin of ± 20 μm is equivalent to a 55 μm pitch in the conventional pattern shape. Further, by narrowing the width of the lead line, the margin can be slightly increased. Further, a short circuit between the first-stage terminal and the second-stage terminal may occur due to the vertical accuracy of the mounting apparatus. It is possible to prevent a short circuit by setting the dimension of the part a in FIG. In order to shorten the length of the terminal portion 8, the number of particles of the anisotropic conductive film is increased, or the structure of the anisotropic conductive film is a two-layer structure having no particle layer and a particle layer. Also good.

  Hereinafter, this embodiment will be described with reference to the drawings. FIG. 5 is a top view in which the display panel of this embodiment and the terminals of the film substrate are connected. The display panel is a TFT liquid crystal panel. A terminal 1 is formed on a glass substrate 2. A resin film is formed on the terminal 1Cr, and the resin part of the terminal part to be connected is opened and covered with ITO. In Example 1, the routing line was exposed, but in Example 2, since the routing part is under the resin, there is no contact on the surface. For this reason, the first stage terminal 3 and the second stage terminal 4 have different short margins, and the width of the first stage terminal width can be increased for both the display panel and the film substrate. The short-circuit restriction due to misalignment is the terminal 4 at the second stage. The configuration of the second stage terminal is the same as that of the first embodiment. In this case, in order to reduce the dimension of the terminal portion 8, it is preferable to make the dimension of the terminal 3 in the first stage shorter than the terminal 4 in the second stage and to make the width of the terminal in the pitch direction as wide as possible. However, the structure is not limited to this, and a TFT display panel or the structure of the first embodiment may be used. In order to shorten the length of the terminal portion 8, the number of particles of the anisotropic conductive film is increased, or the structure of the anisotropic conductive film is a two-layer structure including a particle-free layer and a particle-containing layer. Also good.

The top view which shows the terminal part of the display panel of Example 1 of this invention The perspective view which shows the terminal part of the film substrate of Example 1 of this invention The perspective view of the upper surface which shows the state which aligned the display panel of Example 1 of this invention, and the terminal of a film substrate The perspective view of the upper surface which shows a state when the display panel of Example 1 of this invention and the terminal of a film board | substrate have shifted | deviated from position. The perspective view of the upper surface which shows the state which aligned the display panel of Example 2 of this invention, and the terminal of a film substrate Side view showing a display device Top view showing film substrate Top view showing the display panel Sectional drawing which shows the state which temporarily attached the anisotropic conductive film of the prior art to the display panel Sectional drawing which shows the state which connected the display panel and film substrate of the prior art with the anisotropic conductive film The perspective view seen from the upper surface showing the positional relationship between the terminals after connecting the display panel of the prior art and the film substrate Sectional drawing which shows the state which the display panel and film substrate of the prior art shifted, and were connected with the anisotropic conductive film The perspective view seen from the upper surface showing the positional relationship of the terminals where the display panel and the film substrate of the prior art are connected with a positional shift. Sectional drawing which shows the state which the display panel and film substrate of the prior art short-circuited with the adjacent electrode by position shift, and were connected with the anisotropic conductive film

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Terminal of display panel 2 Glass substrate 3 Terminal of 1st stage 4 Terminal of 2nd stage 5 Polyimide film 6 Terminal which tin-plated Cu 7 Display panel 8 Connected terminal part 9 Film board 10 Driver IC
11 Anisotropic conductive film

Claims (4)

  In the display device in which the display panel and the film substrate are connected by an anisotropic conductive film, the plurality of terminals connected to the display panel and the film substrate are connected in two stages, respectively. Display device.   There are two types of terminal widths for the display panel and the film substrate, the two types of widths are substantially the same for the display panel and the film substrate, and the terminal widths are unified for each stage. The display device according to claim 1, wherein a width of a terminal connecting the display panel and the film substrate is different between the display panel and the film substrate.   2. The display device according to claim 1, wherein terminal widths of the display panel and the film substrate are wider in a terminal width of a second stage than a terminal width of a stage on a terminal tip side.   The display device according to claim 1, wherein an interval between the two stages of terminals is larger than a pitch of the terminals.

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