JP5168612B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device that utilizes light modulation generated by changing the alignment state of liquid crystal.

FIG. 4 is a schematic diagram illustrating a configuration of a main part of an example of the liquid crystal display device.
In this figure, 11 is a liquid crystal cell, 12 is a front polarizing plate, 13 is a rear polarizing plate, 14 is a backlight unit, and 15 is a drive circuit unit.

The liquid crystal cell 11 has a configuration in which a pair of transparent substrates (for example, glass substrates) 18 and 19 provided with transparent electrodes 16 and 17 are overlapped with a gap control material having a diameter of about 5 μm, and the liquid crystal 20 is sealed inside. It has become.
The transparent substrates 18 and 19 are bonded to each other with a sealing material 21, and alignment films 22 and 23 are provided on the side facing the transparent electrodes 16 and 17.

FIG. 5A shows a transparent electrode (first electrode) 17 on one side provided on the transparent substrate 19.
As shown in the figure, the transparent electrode 17 has a segment electrode composed of an electrode 17a corresponding to a character or a figure and a lead lead 17b formed on the surface of the transparent substrate 19 as a conductive pattern.

  The transparent electrode 17 is provided with an external connection terminal 17c for electrically connecting the segment electrode to the drive circuit unit 15, and a pad 17b1 for connecting the common electrode described below to the common electrode external connection terminal 17c1. It has been.

FIG. 5B shows the transparent electrode (second electrode) 16 on the other side provided on the transparent substrate 18.
As shown in the figure, the transparent electrode 16 has a common electrode composed of an electrode 16a corresponding to a character or a figure and a lead 16b formed on the surface of the transparent substrate 18 as a conductive pattern.
The transparent electrode 16 is configured such that the lead lead 16b is electrically connected to the pad 17b1 provided on the transparent electrode 17 using a conductive adhesive or the like.

The liquid crystal display device configured as described above performs display operation by controlling the voltage applied to the transparent electrodes 16 and 17 by the drive circuit unit 15.
For example, by applying a voltage equal to or higher than the threshold voltage to the transparent electrodes 16 and 17, the liquid crystal molecular orientation of the liquid crystal 20 is changed and light is transmitted from the polarizing plate 12.

  Specifically, since light is transmitted through the electrodes 16a and 17a corresponding to the characters and figures of the transparent electrodes 16 and 17 to which voltage is applied, the characters and figures are displayed according to those segments.

On the other hand, the liquid crystal display device as described above has a problem that although the transparent electrodes 16 and 17 are made of a transparent material, they appear thin as an electrode pattern.
In order to solve this problem, transparent electrodes 24 and 25 as shown in FIGS. 6A and 6B have been proposed today.

  The transparent electrode 25 shown in FIG. 6A corresponds to the transparent electrode 17 described above, and is similarly provided with electrodes 25a corresponding to characters and figures, lead leads 25b, pads 25b1, and external connection terminals 25c and 25c1. ing.

  The transparent electrode 25 is formed by providing a transparent conductive film over the entire surface of the transparent substrate 19 and cutting the transparent conductive film with a laser beam or the like so as to surround the segment electrode with a linear groove.

  That is, as shown in enlarged views in FIGS. 7A and 7B, a line having a width of 10 μm to several tens of μm along the periphery of the segment electrode composed of the electrode 25a and the lead lead 25b corresponding to characters and figures. A concave groove 26 is formed.

  In the transparent electrode 25 thus formed, electrodes 25a corresponding to characters and figures, lead leads 25b, pads 25b1, and external connection terminals 25c and 25c1 are formed independently of the other conductive film portions 25d.

The transparent electrode 24 shown in FIG. 6 (B) corresponds to the transparent electrode 16 already described, and from 10 μm along the periphery of the common electrode composed of the electrode 24a corresponding to the characters and figures and the lead 24b. A linear concave groove 27 having a width of several tens of μm is formed.
Therefore, the transparent electrode 24 becomes a common electrode in which the electrode 24a corresponding to the character or figure and the lead lead 24b are formed independently of the other conductive film portion 24d.

  The transparent electrodes 24 and 25 configured as described above are advantageous in the following points as compared with the patterning method using a photoresist which is currently mainstream.

(1) Since the resist coating, exposure, and development steps are not required, the steps can be simplified, and at the same time, the cost can be reduced because a photomask is not used.
(2) Since the electrode etching and residual resist stripping steps are not required, the steps can be simplified.
(3) Various solutions such as a resist and an etching solution are not required, and facilities for treating the waste solution are also unnecessary.
Therefore, it has a positive impact on the environment.

JP 58-1128 A

  The liquid crystal display device including the transparent electrodes 24 and 25 has many advantages as described above. However, the conductive film portions 24d and 25d of the transparent electrodes 24 and 25 are displayed due to static electricity. There's a problem.

  As a case where static electricity is charged in the liquid crystal display device, it is conceivable that the protective films of the polarizing plates 12 and 13 are peeled off when the liquid crystal cell 11 is assembled or inspected.

  Incidentally, since the protective films of the polarizing plates 12 and 13 are provided for preventing the surface of the polarizing plate from being scratched, the protective films are often applied until just before the liquid crystal cell 11 is incorporated into the apparatus main body.

  If static electricity accumulates in the liquid crystal cell 11, the liquid crystal itself has a high resistivity, so that it cannot be discharged through the liquid crystal layer, causing a potential difference due to static electricity on both sides of the liquid crystal layer. For example, the light is transmitted.

  For example, since a normal display unit such as 7 segments is connected to the drive circuit unit 15 to control lighting / non-lighting, it is discharged through the drive circuit unit 15, so there are few problems due to static electricity. The conductive film portions 24d and 25d outside the display portion cannot be discharged through the drive circuit unit 15. Therefore, the conductive film portions 24d and 25d are not easily turned off once they are turned on by applying a voltage due to static electricity. It becomes a problem.

  Therefore, in the present invention, the conductive thin film provided on the transparent substrate is cut into a linear shape, and the advantages of the electrode formed by independently forming the electrodes and leads representing characters and figures with respect to the other conductive film portions are taken into account. Provided is a liquid crystal display device which solves the problem of this electrode due to static electricity.

In order to solve the above-described problems, in the present invention, in the liquid crystal display device, each of the pair of transparent substrates of the liquid crystal cell forms a transparent conductive film over the entire surface of the substrate and cuts the transparent conductive film into a linear shape. One transparent substrate is provided with a first electrode having a segment electrode composed of an electrode corresponding to a character or a figure to be displayed and a lead, and a conductive film portion formed independently of the segment electrode. The transparent substrate is provided with a second electrode having a common electrode composed of an electrode corresponding to a character or a figure to be displayed and a lead, and a conductive film portion formed independently of the common electrode. the first, the second electrode, proposes a liquid crystal display device characterized by their conductive film portions are electrically connected on the transparent substrate.

In the liquid crystal display device of the present invention, it is preferable to electrically connect the conductive film portion outside the effective display portion of the first and second electrodes with a conductive material.
The conductive material described above can be formed by potting a paste material such as silver, copper, or carbon.

  Furthermore, the liquid crystal display device of the present invention contains conductive particles coated with gold, nickel, or the like in a sealing material for bonding a pair of transparent substrates of a liquid crystal cell, and the conductive film portion of the first electrode and the second electrode. The conductive film portion of the electrode can be electrically connected by the conductive particles of the sealing material.

Since the first and second electrodes are electrically connected by the conductive film portion outside the display electrode portion, there is no potential difference between the conductive film portions of the two transparent electrodes. There is no influence by.
As a result, even if static electricity is charged in the liquid crystal cell, lighting display by the conductive film portions of the first and second electrodes does not occur.

Next, embodiments of the present invention will be described with reference to the drawings.
1 shows a first embodiment, FIG. 1A shows a transparent electrode (first electrode) 25 having the same configuration as the transparent electrode shown in FIG. 6A, and FIG. The transparent electrode (2nd electrode) 24 of the same structure as the transparent electrode shown to (B) is shown.

  As in the conventional example, the transparent electrode 24 is provided on the transparent substrate 18 instead of the transparent electrode 16 already described, and the transparent electrode 25 is provided on the transparent substrate 19 instead of the transparent electrode 17. 25 are opposed to each other with the liquid crystal 20 in between.

Further, the transparent electrodes 24 and 25 are configured so as to electrically connect the conductive film portions 24d and 25d so as not to generate a potential difference between the conductive film portions 24d and 25d.
Specifically, a resin that contains silver, copper, carbon, or the like in a part 24P of the conductive film part 24d of the transparent electrode 24 and a part 25P of the conductive film part 25d of the transparent electrode 25. Electrical connection is made by potting a conductive material made of

2 shows a second embodiment, FIG. 2A shows a transparent electrode (first electrode) 25 having the same configuration as the transparent electrode shown in FIG. 6A, and FIG. The transparent electrode (2nd electrode) 24 of the structure substantially the same as the transparent electrode shown to (B) is shown.
In this embodiment, the transparent electrode 24 is provided on the transparent substrate 18 instead of the transparent electrode 16, and the transparent electrode 25 is provided on the transparent substrate 19 instead of the transparent electrode 17.

In this embodiment, the transparent electrodes 24 and 25 are electrically connected using a sealing material 21A that adheres the periphery of the transparent substrates 18 and 19.
The sealing material 21A is the same as the conventional sealing material 21, but in this embodiment, the conductive material 28 coated with gold, nickel, or the like is included in the sealing material 21A.

  That is, as shown in FIG. 3, in the sealing material 21A containing the conductive particles 28, since the dispersion of the conductive particles 28 is sparse, there is no lateral conduction of the conductive particles 28 and the adjacent terminal portions 25c are sealed. There is no short-circuit even if connected through materials.

  In addition, the transparent substrates 18 and 19 are bonded by the sealing material 21A, whereby the conductive films 24d and 25d of the transparent electrodes 24 and 25 facing each other with the sealing material interposed therebetween are electrically connected by the conductive particles 28.

In the present embodiment, the conductive film portion 24d1 of the transparent electrode 24 facing the lead lead portion side (connection side with the external connection terminal) of the transparent electrode 25 is removed so as not to cover the sealing material 21A.
This prevents the lead leads 25b of the transparent electrode 25 from being short-circuited by the conductive film portion 24d of the transparent electrode 24.

While the embodiments of the transmissive liquid crystal display device have been described above, the present invention can also be implemented as a reflective liquid crystal display device.
In this case, a reflecting plate may be provided instead of the backlight. Further, one of the transparent electrodes 24 and 25 may be made opaque and used for reflection without using the rear polarizing plate, Even in this case, it is possible to easily realize a structure in which the entire surface is a reflector, which cannot be realized by a normal electrode structure having no conductive film portion 24d or 25d.

  The present invention can be used as a liquid crystal display device that prevents a lighting display outside the display portion caused by electrostatic charging.

1A and 1B are front views of the first and second electrodes shown as the first embodiment. 2A and 2B are front views of the first and second electrodes shown as the second embodiment. It is explanatory drawing of 2nd Embodiment which electrically connects the electrically conductive film part outside the display part provided in the 1st, 2nd electrode using the sealing material which adhere | attaches a pair of transparent substrate. It is the schematic which showed the principal part structure of the liquid crystal display device of a prior art example. 5A and 5B are front views showing the first and second electrodes provided in the liquid crystal display device described above. FIGS. 6A and 6B are front views showing other conventional examples of the first and second electrodes. 7A is a partially enlarged view of the first electrode shown in FIG. 6A, and FIG. 7B is a cross-sectional view taken along line AA in FIG. 7A.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Liquid crystal cell 12, 13 Polarizing plate 18, 19 Transparent substrate 20 Liquid crystal 21A Sealing material 24 Second electrode 24a Electrode 24b corresponding to character or figure Lead 24d Conductive film portion 24P Part 25 of conductive film portion First Electrode 25a Electrode 25b corresponding to character or figure Lead 25b1 Pad 25c, 25c1 External connection terminal 25d Conductive film portion 25P Part of conductive film portion 26 Linear groove 27 Linear groove 28 Conductive particle

Claims (4)

In liquid crystal display devices,
Each of the pair of transparent substrates of the liquid crystal cell forms a transparent conductive film over the entire substrate surface, and cuts the transparent conductive film into a linear shape,
One transparent substrate is provided with a first electrode having a segment electrode composed of an electrode corresponding to a character or a figure to be displayed and a lead, and a conductive film portion formed independently of the segment electrode,
The other transparent substrate is provided with a second electrode having a common electrode composed of an electrode corresponding to a character or a figure to be displayed and a lead, and a conductive film portion formed independently of the common electrode,
Further, the liquid crystal display device, wherein the first and second electrodes are electrically connected to each other on the transparent substrate. The liquid crystal display device according to claim 1,
In the liquid crystal display device, the first and second electrodes are formed by electrically connecting a conductive film portion with a conductive material in a region excluding an effective region that is a region for displaying characters and figures. The liquid crystal display device according to claim 2,
A liquid crystal display device, wherein the conductive material is formed by potting a paste material such as silver, copper, or carbon. The liquid crystal display device according to claim 1,
A sealing material for bonding a pair of transparent substrates of a liquid crystal cell contains conductive particles coated with gold or nickel, and the conductive film portion of the first electrode and the conductive film portion of the second electrode are sealed. A liquid crystal display device characterized by being electrically connected by conductive particles of a material.

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