JP2786347B2 - Color liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a segment type so-called static type color liquid crystal display for displaying predetermined characters and figures in color.

[0002]

2. Description of the Related Art FIG. 7 is an enlarged plan view of a conventional color liquid crystal display device 1. The color liquid crystal display device 1 has a pair of transparent substrates 16a and 16b made of, for example, glass. Of the pair of transparent substrates, one transparent substrate 16a
Above, a color filter 17 is provided over substantially the entire surface. The color filter 17 is formed by alternately arranging red, green, and blue filters in a band shape or a mosaic shape. In FIG. 9, a red filter,
The green and blue filters are denoted by reference characters R, G, B, respectively. The sizes of the filters R, G, and B are minute, and are so large that they cannot be distinguished by the naked eye.

In the above-described color liquid crystal display device 1, when performing a so-called normally white display in which light is transmitted when no voltage is applied, light transmitted through portions of the color filter 17 other than the filters R, G, and B is blocked. To do
A light blocking layer 15 is provided.

In the case of a so-called normally black display in which light is blocked when no voltage is applied in the color liquid crystal display device 1, the light blocking layer 15 does not need to be provided. However, it is generally known that in a liquid crystal display device, when the refractive index anisotropy of the liquid crystal layer and the thickness of the liquid crystal layer are small, light incident as linearly polarized light becomes elliptically polarized light due to the polarization dispersion phenomenon in the liquid crystal. . Therefore, even in a liquid crystal display device that performs normally black display in which light is blocked when no voltage is applied, if incident light is elliptically polarized by the liquid crystal layer, so-called leaked light that passes through the liquid crystal layer even when no voltage is applied. Occurs. Such leakage light is not preferable because the contrast of the display screen decreases. Therefore, even in a liquid crystal display device that performs a normally black display in order to prevent the occurrence of leakage light even slightly, the light shielding layer 1 is also used.
5 is desirably provided.

FIG. 8 is a sectional view of the liquid crystal display device 1.
A pair of transparent substrates 16a and 16b of the liquid crystal display device 1
Above the transparent common electrode 18 and the segment electrode 20
Is formed, and the common electrode 1 is formed on the glass substrate 16a.
8, a color filter 17 is formed over the entire surface. At this time, the color filter 17 may be formed on the common electrode 18.

As shown in FIG. 7 described above, for example, fine band filters R, G and B of red, green and blue are alternately adjacent to each other, as shown in FIG.
Are formed over almost the entire surface of the filter R, G,
The light blocking layer 15 is formed in the gap between B. Alignment films 19a and 19b are formed so as to cover almost the entire surface of such glass substrates 16a and 16b. For example, a twisted nematic liquid crystal 21 is sealed between the glass substrates 16a and 16b, and a sealing material 22 is provided around the glass substrates 16a and 16b.
Is sealed. Polarizing plates 23 and 24 are disposed on opposite surfaces of the glass substrates 16a and 16b, respectively. Such a liquid crystal display device 1 includes a polarizing plate 2 used.
Normal white display is performed when the pixels 3 and 24 are in a so-called crossed Nicols state, and normally black display state is performed when the cells are in a parallel Nicols state. Thus, the arrangement state of the polarizing plates 23 and 24 is selected.

Here, assume that segment electrodes 41 to 45 and a common electrode 47 for forming a display image as shown in FIG. In FIG. 9, five segment electrodes 41 to 45 have reference numerals S1, S2, S3, respectively.
The electrodes S4 and S5 are connected, and the common electrode 47 is connected.
Is connected to an electrode indicated by reference numeral C. In this state, the display voltage is applied to the segment electrodes 41 to 45 (O
N) / No display (OFF), a display example is shown in Table 1 below.

[0008]

[Table 1]

[0009]

In the complicated pattern of the segment electrodes 41 to 45 as shown in FIG. 9 in the liquid crystal display device 1 described above, the pattern of the common electrode 47 is the same as that of the segment electrodes 41 to 45. (Parts unrelated to display) It is necessary to perform wiring as shown by broken lines so as not to light 48-52. At this time, depending on the shapes of the display patterns 41 to 45 and the routing portions 41 to 45, the wiring pattern of the common electrode 47 may be fine (for example, 100 μm) as indicated by reference numeral 46 in FIG.

In this case, the common electrode portion 47a to which a voltage is applied via the fine wiring pattern 46 has a higher impedance with the electrode C than the other common electrode portions 47b. 47a, 4
The applied voltage for each 7b becomes non-uniform. Therefore, there is a problem that display uniformity is lost. Also, the pattern 46
Because of the small size, a display failure due to disconnection may occur.

An object of the present invention is to solve the above-mentioned technical problems, to make the voltage applied to each common electrode uniform, thereby eliminating display defects and improving the display quality. It is to provide a device.

[0012]

The present invention provides a pair of transparent substrates provided with a liquid crystal layer interposed therebetween, and a color filter provided over the entire surface of one of the pair of transparent substrates, The color filter includes a plurality of filters (R, G, B) for selecting transmitted light to be any one of a plurality of predetermined colors, and a gap between the filters (R, G, B). The filter (R, G, B) and the light-shielding layer BL are provided with a color filter made of a conductive resin composition, and a color filter formed of a conductive resin composition. A color liquid crystal display device comprising: a segment electrode formed in a predetermined display region; and a common electrode formed in a region overlapping the color filter and facing the display region. It is.

Further, the present invention is characterized in that the conductive resin composition has a volume resistivity of 200 Ω · m or less.

[0014]

According to the present invention, the color filter having the filters R, G, B and the light-shielding layer BL between the filters R, G, B is formed of a conductive resin composition. Even if the common electrode formed on the color filter is connected through a fine pattern, the common electrode is electrically connected by the color filter when the fine pattern is formed on the same color filter, The impedance of the electrode can be made uniform.
Since the light-shielding layer BL is formed in a region where no display is performed because the region is not opposed to the segment electrode, there is no inconvenience that a display of a routing portion for applying a voltage to the segment electrode can be seen.

A common voltage is simultaneously applied to these common electrodes. At this time, display is performed by selectively applying a voltage to the segment electrodes.

When the volume resistivity of the conductive resin composition is selected to be 200 Ω · m or less, a good effect of lowering the impedance of the common electrode can be obtained.

[0017]

FIG. 1 is a sectional view showing the structure of a color liquid crystal display device 25 according to an embodiment of the present invention. The color liquid crystal display device 25 includes a pair of transparent substrates 26a and 26b made of glass, plastic, or the like, and a color filter 27 is formed on substantially one entire surface of the transparent substrate 26a. The color filter 27 includes, for example, three color filters formed in a fine rectangular shape, for example, a red filter R, a green filter G, and a blue filter B.
And a black light shielding layer BL provided in a gap between the filters, and is formed by a method such as a dyeing method, a printing method, an electrodeposition method, or a pigment dispersion method. On the color filter 27, a common electrode 28 is formed. Transparent substrate 2 on which color filter 27 and common electrode 28 are formed
An alignment film 29a is formed on 6a. Further, the color filter 27 may be formed on the common electrode 28.

A segment electrode 30 is formed on one surface of the transparent substrate 26b. At this time, the common electrode 2
8 is formed in a region including at least a region where the segment electrode 30 faces. Further, an alignment film 29b is formed on the transparent substrate 26b on which the segment electrodes 30 are formed.

The transparent substrates 26a and 26b are arranged so that the surfaces on which the alignment films 29a and 29b are formed face each other. The liquid crystal layer 31 is interposed between the transparent substrates 26a and 26b, and is sealed by a sealing material 32. On the surfaces of the transparent substrates 26a and 26b opposite to the liquid crystal layer 31,
Polarizing plates 33 and 34 are arranged respectively.

The alignment films 29a and 29b are formed to a thickness of 600.degree. Using, for example, a polyimide resin, and the alignment direction of the liquid crystal molecules is 90 degrees between the transparent substrates 26a and 26b.
Twisted to form, for example, a left-rotating liquid crystal layer,
Rubbed with nylon woven fabric.

To keep the distance between the transparent substrates 26a and 26b constant, a plastic spacer (not shown) is interposed between these substrates. The distance between the substrates is set to, for example, 5 μm by the spacer.
As the sealing material 32 for sealing the liquid crystal layer 31, for example, epoxy resin is used. For the liquid crystal layer 31, for example, a phenylcyclohexane-based mixed liquid crystal is selected. Further, cholesteric nonanoate is added to the liquid crystal layer 31 to impart levorotation.

Further, between the transparent substrates 26a and 26b,
Rubbing treatment may be performed on the alignment films 29a and 29b so that the alignment direction of the liquid crystal molecules is twisted by 90 degrees to form a liquid crystal layer with right-handedness. In this case, for the liquid crystal layer 31, a phenylcyclohexane-based mixed liquid crystal to which GB-10 (manufactured by Merck) is added as a dextrorotatory chiral substance is used.

FIG. 2 is a plan view of the color filter 27, FIG. 3 is an enlarged plan view of the color filter 27, and FIG.
7 is an enlarged sectional view near the color filter 27. FIG. In the color liquid crystal display device 21, the color filter 27 is provided over substantially the entire surface of the transparent substrate 26a. The color filter 27 is formed by mixing fine particles of, for example, gold (Au), and thus has conductivity. Thereby, the resistance value of the common electrode can be controlled. The red, green and blue filters R, G and B are arranged in a matrix or mosaic.

2 to 4, the red filter is indicated by reference numeral R, the green filter is indicated by reference sign G, and the blue filter is indicated by reference sign B. The sizes of the filters R, G, and B are minute, and are so large that they cannot be distinguished by the naked eye. For each of the filters R, G, and B formed so as to overlap the common electrode 28, segment electrodes indicated by reference numerals 53, 54, and 55 in FIG. 3 are formed on the transparent substrate 26b. These segment electrodes 53, 54, 55 are indicated generally by the reference numeral 30.

As an example, rectangular filters R, G, B having a length L1 = 290 μm and a width L2 = 70 μm are used, and the interval L3 between the filters is selected to be 40 μm.
Therefore, the area formed by the three types of filters R, G, and B arranged in the width direction E of the filter is 3
It is a 30 μm × 330 μm square.

The distance L3 between the filters is determined by the accuracy of manufacturing the color filter such as a photo process, and is generally 15 μm to 40 μm.

In the arrangement of the filters, for example, a permutation of RGB is repeated in the width direction E2 of the filter. The shapes of the filters R, G, and B may be square or other shapes.

A light-shielding layer BL is formed between the filters R, G, and B. For the light shielding layer BL, for example, a photosensitive pigment dispersion in which carbon black is dispersed in a photopolymer is used. By mixing carbon black,
The light-shielding layer BL has conductivity, and thus the light-shielding layer BL is also made of a conductive resin composition like the filters R, G, and B. As described above, the color filter 27 is constituted by the filters R, G, B and the light shielding layer BL.

FIG. 5 is an enlarged plan view of the common electrode 28. For example, the common electrode 28 is formed in an area of 100.1 mm × 100 mm, and a lead wire (leading portion)
100 μm width, 100 μm spacing between leader lines
m, that is, the line pitch is 200 μm. The common electrode 28 is made of, for example, an indium oxide film (ITO).
Film: a transparent conductive film using Indium Tin Oxide), area resistance 500Ω / □, film thickness 200 膜厚
It is. At this time, the resistance value of the common electrode 28 is 250 M
Ω.

Next, 100 between the leader line and the leader line
The resistance value when the conductive color filter 27 contacts the common electrode 28 in the area A of μm × 100 μm,
Table 2 below shows the sheet resistance and volume resistivity of the color filter.
And the graph of FIG.

[0031]

[Table 2]

The effect of lowering the resistance of the common electrode 28 by making the color filter 27 conductive is confirmed when the volume specific resistance is 200 Ωm or less.

As described above, according to the present embodiment, since the color filter 27 is formed of the conductive resin composition, when the fine lead portion of the common electrode 28 is formed on the same color filter, Since the connection is made via the connection 27, the impedance of the common electrode 28 can be reduced and made uniform. Thus, the applied voltage can be made uniform, and the display quality can be improved. In addition, even if a disconnection occurs in a fine wiring portion, since conduction is performed via the color filter 27,
Appropriate applied voltage is applied to the common electrode 28, so that occurrence of display failure can be prevented.

[0034]

As described above, according to the present invention, the color filter composed of the filters R, G, B and the light-shielding layer BL is formed of a conductive resin composition.
Even if the common electrode itself formed on the color filter is a fine pattern, or as described in connection with the above-described related art, even if there is a fine portion in the wiring pattern for applying a voltage to the common electrode. When the fine parts are formed on the same color filter, the common electrode and a fine wiring pattern for applying a voltage to the common electrode are conducted by the color filter, and the impedance of the common electrode is made uniform. Can be. This makes it possible to equalize the voltage applied to each common electrode,
The display quality can be improved. Further, even if the electrodes are disconnected, the display is not affected because they are electrically connected by the color filters.

When the volume resistivity of the conductive resin composition is selected to be 200 Ω · m or less, a good effect of lowering the impedance of the common electrode can be obtained.

[Brief description of the drawings]

FIG. 1 shows a color liquid crystal display device 2 according to an embodiment of the present invention.
It is sectional drawing which shows the structure of No. 5.

FIG. 2 is a plan view of a color filter 27.

FIG. 3 is an enlarged plan view of a color filter 27.

FIG. 4 is an enlarged sectional view near a color filter 27.

FIG. 5 is an enlarged plan view of a common electrode 28.

FIG. 6 shows the resistance value of the common electrode 28 and the color filter 27.
3 is a graph showing a correspondence relationship between the sheet resistance value and the volume specific resistivity.

FIG. 7 is an enlarged plan view of a conventional color liquid crystal display device 1.

FIG. 8 is a cross-sectional view of a conventional liquid crystal display device 1.

FIG. 9 is a plan view showing a wiring pattern of a segment electrode and a common electrode in a conventional example.

[Explanation of symbols]

 25 color liquid crystal display device 26a, 26b transparent substrate 27 color filter 28 common electrode 30 segment electrode 31 liquid crystal layer BL light shielding layer R red filter G green filter B blue filter

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shuichi Uebe 22-22, Nagaikecho, Abeno-ku, Osaka City Inside Sharpe Corporation (72) Inventor Mitsuaki Shioji 22-22, Nagaikecho, Abeno-ku, Osaka City Inside Sharpe Corporation ( 56) References JP-A-1-295224 (JP, A) JP-A-63-226626 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02F 1/1335 G02F 1/1343 G09F 9/30

Claims (2)

(57) [Claims] 1. A pair of transparent substrates provided with a liquid crystal layer interposed therebetween, and a color filter provided over an entire surface of one surface of one of the pair of transparent substrates, wherein the color filter transmits transmitted light. A plurality of filters (R, G, B) for selecting any one of a plurality of predetermined colors, and a light shielding layer BL provided in a gap between the filters (R, G, B) are provided. And the filter (R,
G, B) and the light-shielding layer BL, a color filter made of a conductive resin composition, a segment electrode formed in a predetermined display area on one surface of the other transparent substrate among the pair of transparent substrates, And a common electrode formed in a region facing the display region so as to overlap with the display region. 2. The color liquid crystal display device according to claim 1, wherein the conductive resin composition has a volume resistivity of 200 Ω · m or less.