JP2010054909A - Liquid crystal display device - Google Patents

Abstract

Provided is a liquid crystal display device capable of preventing charging of another substrate without providing a grounding pad on one substrate constituting a liquid crystal panel.
A liquid crystal display device is disposed opposite to a TFT glass substrate 10 so as to sandwich a liquid crystal layer together with the TFT glass substrate 10 and an ITO (conductive film) is formed on a surface opposite to the liquid crystal layer. The conductive region connected to the ground potential other than the region on the TFT glass substrate 10 side is mounted on a region excluding the region facing the CF glass substrate 12 on the liquid crystal layer side surface of the CF glass substrate 12 and the TFT glass substrate 10 A conductive tape 18 connecting the liquid crystal driving semiconductor chip 14 exposed on at least a part of the surface of the substrate, the ITO formed on the CF glass substrate 12, and the conductive region formed on the liquid crystal driving semiconductor chip 14; Including a liquid crystal panel.
[Selection] Figure 1

Description

  The present invention relates to a liquid crystal display device, and more particularly to a technique for preventing charging of a liquid crystal panel.

  The liquid crystal display device includes a liquid crystal panel including a liquid crystal layer and a pair of transparent substrates (a first substrate and a second substrate) that sandwich the liquid crystal layer.

  FIG. 5 is a diagram illustrating an example of a liquid crystal panel included in a conventional liquid crystal display device. As shown in the figure, a conventional liquid crystal panel includes a TFT (Thin Film Transistor) glass substrate (first substrate) 10, a CF (Color Filter) glass substrate (second substrate or counter substrate) 12, a liquid crystal. A driving semiconductor chip 15, a flexible printed circuit (FPC) 16, a grounding pad 26, and a conductive resin 28 are included.

  A liquid crystal driving semiconductor chip 15 and one end of the FPC 16 are mounted on the surface (upper surface) of the TFT glass substrate 10 on the liquid crystal layer side (upper surface), and a grounding pad 26 is formed. . The liquid crystal driving semiconductor chip 15 is connected to a signal wiring (not shown) of the FPC 16 and controls a voltage applied between a pixel electrode and a counter electrode formed on the liquid crystal panel. The ground pad 26 is connected to a ground wiring (not shown) of the FPC 16.

  On the back surface (the surface opposite to the liquid crystal layer) of the CF glass substrate 12, ITO (Indium Tin Oxide) is formed on the entire surface. The ITO is a conductive film provided to prevent the liquid crystal panel from being charged, and is connected to the grounding pad 26 via a conductive resin 28. In particular, in an IPS (In-Plain Switching) type liquid crystal display device, a pixel electrode and a counter electrode are provided on the surface of the first substrate 10 on the liquid crystal layer side, and the liquid crystal layer side of the second substrate 12 is provided. Since the counter electrode is not provided on the surface, such a conductive film is often provided. A conductive tape may be used instead of the conductive resin 28.

Patent Documents 1 to 3 disclose a method of connecting ITO formed on the back surface of the CF glass substrate to the ground potential.
JP 2007-140353 A JP-A-9-105918 Japanese Patent Laid-Open No. 10-268783

  However, in the above conventional liquid crystal display device, it is necessary to secure a region for providing a grounding pad. Therefore, when the size and number of driver chips increase as the liquid crystal panel becomes higher definition, When the number increases, there arises a problem that it becomes difficult to arrange driver chips and wiring on the surface of the TFT substrate on the liquid crystal layer side.

  The present invention has been made in view of the above problems, and provides a liquid crystal display device capable of preventing charging of the other substrate without providing a grounding pad on one substrate constituting the liquid crystal panel. With the goal.

  In order to solve the above-described problems, a liquid crystal display device according to the present invention is arranged to face a first substrate and the first substrate so as to sandwich the liquid crystal layer together with the first substrate, and is a surface opposite to the liquid crystal layer And a conductive region mounted on a region excluding a region facing the second substrate on a surface of the first substrate on the liquid crystal layer side and connected to a ground potential. A conductive member connecting the semiconductor element exposed on at least a part of the surface other than the first substrate side, the conductive film formed on the second substrate, and the conductive region formed on the semiconductor element; It is characterized by including.

  According to the present invention, charging of the second substrate can be prevented without providing a grounding pad on the surface of the first substrate on the liquid crystal layer side.

  In one embodiment of the present invention, a ground electrode connected to a ground potential is formed on a surface of the semiconductor element on the first substrate side, and the conductive region formed in the semiconductor element includes: Conducts to the ground electrode.

  In one embodiment of the present invention, the conductive region formed in the semiconductor element is an N-type or P-type semiconductor substrate constituting the semiconductor element, and the semiconductor substrate has the same polarity as the semiconductor substrate. And a diffusion layer that is electrically connected to the ground electrode is formed.

  In one embodiment of the present invention, the conductive region formed in the semiconductor element is a metal layer formed on a surface of the semiconductor element opposite to the first substrate.

  In one embodiment of the present invention, the conductive member is a conductive tape.

  In one embodiment of the present invention, an insulating resin is applied to a region of the surface on the liquid crystal layer side of the first substrate that faces the conductive member. In this aspect, the conductive member may be a conductive resin.

  In each of the above aspects, the semiconductor element may be a liquid crystal driving semiconductor element. Further, a thin film transistor may be formed on the surface of the first substrate on the liquid crystal layer side, and a color filter layer may be formed on the surface of the second substrate on the liquid crystal layer side. .

  In one embodiment of the present invention, the ground electrode formed on the semiconductor element is electrically connected to a ground wiring of a flexible printed board connected to the first substrate.

  In one embodiment of the present invention, the first substrate includes a pixel electrode and a counter electrode, and the liquid crystal layer is driven and displayed by an electric field generated by a potential difference between the pixel electrode and the counter electrode. I do.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a configuration diagram of a liquid crystal panel included in a liquid crystal display device according to an embodiment of the present invention. This liquid crystal panel is an IPS (In-Plain Switching) type liquid crystal panel used for mobile phones, for example, and as shown in the figure, a TFT glass substrate (first substrate) 10 and a CF glass substrate. A (second substrate) 12, a liquid crystal driving semiconductor chip 14, a flexible printed circuit board (FPC) 16, and a conductive tape 18 are included.

  The TFT glass substrate 10 and the CF glass substrate 12 are arranged to face each other so as to sandwich a liquid crystal layer (not shown).

  A thin film transistor, a pixel electrode to which a video signal is supplied via the thin film transistor, and a counter electrode are formed on the surface of the TFT glass substrate 10 on the liquid crystal layer side. An alignment film for aligning liquid crystal molecules contained in the liquid crystal layer in a predetermined direction is formed on the surface of the TFT glass substrate 10 on the liquid crystal layer side.

  On the surface of the CF glass substrate 12 on the liquid crystal layer side, a color filter layer in which the three primary colors (RGB) of light are arranged and an alignment film are formed so as to face each pixel electrode formed on the TFT glass substrate 10. Yes. Further, ITO, which is a transparent conductive film, is formed on the surface (back surface) opposite to the liquid crystal layer of the CF glass substrate 12. The conductive film is formed on the entire surface of the CF glass substrate 12 or almost the entire surface (region including at least the display region).

  The liquid crystal molecules sandwiched and sealed between the TFT glass substrate 10 and the CF glass substrate 12 are arranged in accordance with the voltage between the pixel electrode formed on the TFT glass substrate 10 and the counter electrode. Change. That is, when the voltage between the pixel electrode and the counter electrode is off, the liquid crystal molecules are arranged in the predetermined direction, and when the voltage between the pixel electrode and the counter electrode is on, the liquid crystal molecules Are arranged along the direction of the electric field generated between the electrode and the counter electrode. In this way, display is performed by driving the liquid crystal layer by the electric field generated by the potential difference between the pixel electrode and the counter electrode.

  The liquid crystal driving semiconductor chip 14 is a semiconductor element mounted on a region on the liquid crystal layer side of the TFT glass substrate 10 excluding a region facing the CF glass substrate 12, and is a thin film transistor formed on the TFT glass substrate 10. Each switching operation is controlled. A conductive region connected to the ground potential is exposed on at least a part of the surface (the top surface and the side surface excluding the back surface) other than the TFT glass substrate 10 side of the liquid crystal driving semiconductor chip 14.

  FIG. 3 is a cross-sectional view of a liquid crystal driving semiconductor chip 14 a which is an example of the liquid crystal driving semiconductor chip 14. As shown in the figure, the liquid crystal driving semiconductor chip 14a is formed on a P-type semiconductor substrate 30, a P-type diffusion layer 31 and an N-type diffusion layer 32 formed on the P-type semiconductor substrate 30, and a chip back surface. The bump 41 to which the ground potential “0V” is applied, the bump 42 to which the power supply potential “5V” is applied, the through holes 33 and 37 that connect the P-type diffusion layer 31 to the bump 41, the metal wirings 35 and 39, N Through holes 34 and 38 for electrically connecting the mold diffusion layer 32 to the bumps 42 and metal wirings 36 and 40 are configured.

  The liquid crystal driving semiconductor chip 14 a is mounted on the TFT glass substrate 10 so that the bumps 41 and the bumps 42 formed on the back surface thereof are electrically connected to the ground wiring and the power supply wiring of the FPC 16 connected to the TFT glass substrate 10. Is done.

  An N-type transistor (N-TR) is formed in the P-type diffusion layer 31, and a P-type transistor (P-TR) is formed in the N-type diffusion layer 32. The P-type semiconductor substrate 30 and the N-type diffusion layer 32 are joined by a diode (DIODE) that allows current to flow from the P-type semiconductor substrate 30 toward the N-type diffusion layer 32.

  In the liquid crystal driving semiconductor chip 14a having such a configuration, the P-type semiconductor substrate 30 and the P-type diffusion layer 31 having the same polarity have the same potential. As described above, since the P-type diffusion layer 31 is electrically connected to the bump 41 connected to the ground potential, the potential of the P-type semiconductor substrate 30 also becomes the ground potential. Thus, in the liquid crystal driving semiconductor chip 14a, the P-type semiconductor substrate 30 connected to the ground potential is exposed on the upper surface and part of the side surface.

  Although the example in which the P-type semiconductor substrate 30 is connected to the ground potential is shown here, the liquid crystal driving semiconductor chip 14a is configured so that the N-type semiconductor substrate is connected to the ground potential via the N-type diffusion layer. You may have the structure which reversed the polarity of P type and N type.

  As shown in FIG. 2, the conductive tape 18 is formed of a conductive region (P-type semiconductor) connected to the ITO formed on the back surface of the CF glass substrate 12 and the ground potential exposed on the upper surface or side surface of the liquid crystal driving semiconductor chip 14. The substrate 30 or a metal layer 51 described later is connected. Thereby, the ITO formed on the back surface of the CF glass substrate 12 is connected to the ground potential, and the CF glass substrate 12 is prevented from being charged.

  The conductive tape 18 is bonded so that it does not bend, for example, so that the conductive tape 18 does not come into contact with bumps formed on the liquid crystal driving semiconductor chip 14 or other terminals formed on the TFT glass substrate 10. Alternatively, an insulating resin such as epoxy may be applied to a region facing the conductive tape 18 on the surface of the TFT glass substrate 10 on the liquid crystal layer side. Further, instead of the conductive tape 18, a conductive member such as a conductive resin may be used. In the case where a conductive resin is used instead of the conductive tape 18, it is desirable to provide the insulating resin in the region of the surface of the TFT glass substrate 10 facing the conductive resin in order to prevent a short circuit.

  4 is a cross-sectional view of a liquid crystal driving semiconductor chip 14b, which is another example of the liquid crystal driving semiconductor chip 14. As shown in FIG. As shown in the figure, the liquid crystal driving semiconductor chip 14b includes a metal layer 51 formed on the upper surface of the P-type semiconductor substrate 30 via an insulating layer 50 on the liquid crystal driving semiconductor chip 14a shown in FIG. The bump 56 connected to the ground potential formed on the back surface of the chip, and the through holes 52 and 54 and the metal wirings 53 and 55 for conducting the metal layer 51 to the bump 56 are further added. In the liquid crystal driving semiconductor chip 14b, the metal layer 51 exposed on the upper surface is connected to the ground potential. It is assumed that through hole 52 is conducted only to metal layer 51 and metal wiring 53 and is insulated from P-type semiconductor substrate 30.

  If the metal layer 51 and ITO formed on the back surface of the CF glass substrate 12 are connected by the conductive tape 18, the ITO formed on the back surface of the CF glass substrate 12 is connected to the ground potential, and the CF glass substrate 12 Is prevented from being charged. In this case, static electricity generated in the CF glass substrate 12 flows not into the P-type semiconductor substrate 30 but into the metal layer 51 insulated from the P-type semiconductor substrate 30 through the insulating layer 50 and the through holes 52. Therefore, the influence of static electricity flowing from the CF glass substrate 12 to the P-type semiconductor substrate 30 on the potential of the N-type diffusion layer 32 formed on the P-type semiconductor substrate 30 can be reduced.

  According to the liquid crystal display device including the liquid crystal panel described above, charging of the CF glass substrate 12 can be prevented without providing a grounding pad on the surface of the TFT glass substrate 10 on the liquid crystal layer side. That is, a sufficient free area can be secured on the surface of the TFT glass substrate 10 on the liquid crystal layer side. As a result, a plurality of lighting test pads 20, 22, and 24 can be mounted on the surface of the TFT glass substrate 10 on the liquid crystal layer side as shown in FIG. . Also, for example, all three driver chips necessary for high definition of a liquid crystal panel using amorphous silicon TFTs can be mounted on the surface of the TFT substrate on the liquid crystal layer side.

  The present invention is not limited to the above embodiment.

  For example, in a semiconductor element connected to ITO formed on the back surface of the CF glass substrate 12 through a conductive member such as the conductive tape 18, a conductive region connected to the ground potential is exposed on at least a part of the upper surface or the side surface. Any semiconductor chip may be used as long as it is a liquid crystal driving semiconductor chip.

  Further, the present invention is not limited to the IPS liquid crystal panel, but can be applied to a liquid crystal display device including another type of liquid crystal panel. For example, even when the counter electrode is formed not on the TFT glass substrate 10 side but on the surface on the liquid crystal layer side on the CF glass substrate 12 side, the back surface of the CF glass substrate 12 is used for the purpose of improving the antistatic effect. The present invention is also applicable to a liquid crystal display device in which a conductive film such as ITO is formed.

It is a block diagram of the liquid crystal panel contained in the liquid crystal display device which concerns on embodiment of this invention. It is a block diagram of the liquid crystal panel contained in the liquid crystal display device which concerns on embodiment of this invention. It is sectional drawing of an example of the semiconductor chip for a liquid crystal drive concerning embodiment of this invention. It is sectional drawing of the other example of the semiconductor chip for a liquid crystal drive which concerns on embodiment of this invention. It is a figure which shows an example of the liquid crystal panel contained in the conventional liquid crystal display device.

Explanation of symbols

  10 TFT glass substrate, 12 CF glass substrate, 14, 15 Liquid crystal driving semiconductor chip, 16 Flexible printed circuit board (FPC), 18 Conductive tape, 20, 22, 24 Lighting inspection pad, 26 Grounding pad, 28 Conductive resin, 30 P type semiconductor substrate, 31 P type diffusion layer, 32 N type diffusion layer, 33, 34, 37, 38, 52, 54 Through hole, 35, 36, 39, 40, 53, 55 Metal wiring, 41, 42, 56 bumps, 50 insulating layers, 51 metal layers.

Claims (12)

A first substrate;
A second substrate disposed opposite to the first substrate so as to sandwich the liquid crystal layer together with the first substrate, and having a conductive film formed on a surface opposite to the liquid crystal layer;
The conductive region mounted on the liquid crystal layer side surface of the first substrate excluding the region facing the second substrate and connected to the ground potential is provided on at least a part of the surface other than the first substrate side. An exposed semiconductor element;
A conductive member connecting the conductive film formed on the second substrate and the conductive region formed on the semiconductor element;
A liquid crystal display device comprising: The liquid crystal display device according to claim 1.
A ground electrode connected to a ground potential is formed on the surface of the semiconductor element on the first substrate side,
The conductive region formed in the semiconductor element is electrically connected to the ground electrode;
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 2,
The conductive region formed in the semiconductor element is an N-type or P-type semiconductor substrate constituting the semiconductor element,
The semiconductor substrate has a diffusion layer having the same polarity as the semiconductor substrate and conducting to the ground electrode.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 2,
The conductive region formed in the semiconductor element is a metal layer formed on a surface of the semiconductor element opposite to the first substrate.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1.
The conductive member is a conductive tape.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1.
An insulating resin is applied to a region facing the conductive member of the surface of the first substrate on the liquid crystal layer side,
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 6.
The conductive member is a conductive resin.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1.
The semiconductor element is a liquid crystal driving semiconductor element.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1.
A thin film transistor is formed on the liquid crystal layer side surface of the first substrate.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1.
A color filter layer is formed on the surface of the second substrate on the liquid crystal layer side.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1.
The ground electrode formed on the semiconductor element is electrically connected to a ground wiring of a flexible printed circuit board connected to the first substrate;
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1.
The first substrate has a pixel electrode and a counter electrode,
Display by driving the liquid crystal layer by an electric field generated by a potential difference between the pixel electrode and the counter electrode;
A liquid crystal display device characterized by the above.

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