JP2001337318A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a liquid crystal display element to cope with a gradation display while gradually varying the color tone of a specified display color along a specified direction by a simple photomask design and also to freely set the gradation grade. SOLUTION: For example, a first blue coloring layer 41 and a second light blue coloring layer 43 are formed as a wedge shaped engaging pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a colored layer on the inner surface of a substrate, and more particularly, to a liquid crystal display device having a gradation display function in which the color tone of the display color gradually changes in a specific direction. It relates to an element.

[0002]

2. Description of the Related Art In a color display liquid crystal display device having a colored layer on the inner surface of a substrate, a method of realizing a display having a so-called gradation in which the color tone changes smoothly along a specific direction is roughly divided into the following two methods. Methods are known.

For example, a description will be given of character dot display using 5 × 7 dots (pixels) as one display unit.
Is a method in which different colors are blended for each pixel and shaded along the display, for example, in the vertical direction. The second method is a method in which each pixel is decomposed into smaller pixels, and color adjustment is performed by gradually changing the occupancy of two colors in a large pixel.

[0004]

However, the first method has a problem that the number of man-hours increases and the cost increases because the number of blended colors is large.

In the second method, although the color can be freely adjusted, a high precision of a photomask and a high positional accuracy of coloring are required to produce fine pixels. There was a problem that the above burden was large.

[0006]

According to a feature of the present invention,
Since a very high coloring position accuracy is not required, it is possible to cope with a simple photomask design, and the gradient of the gradation can be set freely.

That is, the present invention includes a pair of electrode substrates that are opposed to each other with a liquid crystal layer interposed therebetween, and one of the electrode substrates is provided with a colored layer on an inner surface thereof. In a liquid crystal display device having a gradation display function in which the color tone of the display color gradually changes along a specific direction, the predetermined display area on the inner surface of the one electrode substrate is colored with different translucent colors. A first coloring layer and a second coloring layer are provided, and each of these coloring layers is formed as a wedge-shaped meshing pattern along the specific direction.

[0008] In the present invention, preferably, the first colored layer and the second colored layer use the same shade of light and shade. For example,
Assuming that the first colored layer is blue, light blue is selected for the second colored layer, and these two colors are formed as a wedge-shaped meshing pattern, so that the display color within a predetermined display area is changed. The color tone gradually changes, for example, from blue to light blue or from light blue to blue along the vertical direction of the display.

In order to make the gradation uniform over the entire surface of the display, it is preferable that both the first coloring layer and the second coloring layer have a basic pattern as a unit pattern which is repeated regularly.

In obtaining the wedge-shaped engagement pattern, one of the basic patterns is an upright triangle, while the other is an inverted triangle (inverted triangle). According to the present invention, there may be an overlap of, for example, about 30 μm between the respective hypotenuses.

This means that a photomask used for forming a colored layer does not require high precision.
Although the rate of change of gradation depends on the triangular shape of each basic pattern, according to a preferred aspect of the present invention,
Extremely sharp isosceles or right triangles are employed.

Regarding the transparent electrodes formed on each electrode substrate, each transparent electrode may be a so-called solid electrode, but one of the row electrodes or the column electrodes is provided on one of the electrode substrates having the coloring layer. A first electrode is formed, and a second electrode serving as the other of a row electrode or a column electrode is formed on the other electrode substrate side.
Electrodes are formed, and a black mask that blocks light between the electrodes and that defines one pixel (dot) is formed in a grid pattern on any one of the electrode substrates.
In the liquid crystal display element of the character dot display in which a dot is one display unit, it is preferable that the specific direction in which the color tone changes is the extending direction of the first electrode.

That is, as described above, according to the present invention, an overlapping portion (step portion) of the first coloring layer and the second coloring layer.
Although there may be, when a transparent electrode is formed on these colored layers, even if a crack occurs in the transparent electrode due to the step, the crack generation direction is not the direction crossing the transparent electrode. This is because, in the extending direction, the probability of disconnection of the transparent electrode is reduced.

In the case of the liquid crystal display element for displaying the character dots, the wedge-shaped engagement pattern may be formed over a plurality of the pixels. Further, it is preferable that the first colored layer or the second colored layer is also formed on the black mask provided between the first electrodes in accordance with the width of the mask. So-called light leakage can be prevented even if there is a deviation from the coloring layer.

More specifically, the first colored layer and the second colored layer
The coloring layer is preferably a pigment in which a pigment is dispersed in a photosensitive resin. According to this, the degree of freedom of the pattern shape of the first coloring layer and the second coloring layer is improved, and a sharp triangular shape is obtained. Can also be easily formed.

In the present invention, it is not always necessary to provide both the first and second colored layers and the black mask on one electrode substrate side. For example, the first and second colored layers are provided on one electrode substrate side. May be formed, and a black mask may be provided on the other electrode substrate side. Further, the present invention is also applicable to a liquid crystal display element of full dot display and segment display.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a basic embodiment of the present invention will be described with reference to FIG.
Has a first electrode substrate 2 and a second electrode substrate 3.
Each of the electrode substrates 2 and 3 may be made of glass or plastic. In this case, a colored layer 4 in which a pigment is dispersed in a photosensitive resin is provided on the inner surface side of the first electrode substrate 2. The transparent electrode 5 is formed on the colored layer 4. On the inner surface side of the second electrode substrate 3, a transparent electrode facing the transparent electrode 5 is formed.

Each of the electrode substrates 2 and 3 is pressure-bonded via a peripheral sealing material 7 made of epoxy resin or the like, and a predetermined liquid crystal material 8 is sealed in the cell gap. Although not shown, an alignment film is actually formed on each of the transparent electrodes 5 and 6, and at least one of the electrode substrates 2 and 3 is provided with a terminal portion or the like in series. .

Next, the basic configuration of the coloring layer 4 will be described with reference to FIG. The coloring layer 4 includes two coloring layers of a first coloring layer 41 and a second coloring layer 43. In this example,
The first coloring layer 41 has a blue color, and the second coloring layer 43 has a light blue color.

The first coloring layer 41 and the second coloring layer 43 are formed as a wedge-shaped engagement pattern. here,
Assuming that the vertical direction of the display area (display screen) coincides with the vertical direction of FIG. 2, in this example, the first colored layer 41 is formed as a sharp erect isosceles triangle. The second colored layer 43 is formed in a shape in which the first colored layer 41 is inverted, that is, as a sharp inverted isosceles triangle.

The angle of the apex angle of the colored layers 41 and 43 and the number of arrangements may be arbitrarily selected, and unlike the example of FIG. 2, the colored layers 41 and 43 may have, for example, a sharp right-angled triangular shape. However, in any case, since the colored layers 41 and 43 are meshed in a wedge shape, the ratio of the blue color is large on the lower side of the display area, and the ratio is reversed toward the upper side, and the light blue color is reversed. The percentage increases.

In the example shown in FIG. 2, the colored layers 41 and 43 are both formed between the lower side and the upper side of the display area. Good. Further, each vertex may be rounded, or the boundary between the colored layers 41 and 43 may be formed in an arc shape or a wavy shape instead of a straight line. In the display area having the colored layers 41 and 43, the transparent electrodes 5 and 6 may be so-called solid electrodes or may be formed in a matrix arrangement.

The present invention also includes the deformation pattern shown in FIG. This deformation pattern is understood to include two basic form patterns of FIG. That is, this deformation pattern is obtained by combining the basic form pattern of FIG. 2 with the same basic form pattern by inverting it by 180 degrees.
The colored layer 41a is formed in a diamond shape, and the diamond includes two first colored layers 41, 41.

According to this deformation pattern, a gradation is obtained such that the ratio of blue color is large at the center portion side of the display region, and the ratio of light blue color is increased from the center portion toward the upper side and lower side of the display region. Can be If the arrangement of the first colored layer 41a and the second colored layer 43 is exchanged, a gradation opposite to the above is obtained.

Next, an example in which the present invention is applied to a character dot display type liquid crystal display device will be described with reference to FIGS. FIG. 4 is a plan view of the inner surface of the first electrode substrate 2 shown in FIG. 1, and a black mask BM is formed in a grid on the inner surface of the substrate. Each pixel D for character dot display is defined. Each pixel D is 0.3 to
The size may be about 5 mm square, but in this embodiment, it is 1 mm square.

In this example, the transparent electrode 5 of the first electrode substrate 2 is formed as a striped column electrode (Y electrode) along the vertical direction in FIG.
The transparent electrode 6 is formed as a striped row electrode (X electrode) orthogonal to the column electrode. The space between the column electrodes and the space between the row electrodes is shielded by the black mask BM.

First, as shown in FIG.
Is coated with a photosensitive resin in which a pigment exhibiting a blue color is dispersed, exposed to light with a predetermined photomask, and developed to form a sharp isosceles triangular (wedge-shaped) first resin.
The coloring layer 41 is formed. In this case, the direction of the first colored layer 41 is set to the vertical direction in the drawing according to the direction of the transparent electrode 5 formed as a column electrode thereafter.

It is preferable that the arrangement pitch of the first colored layers 41 is such that it is not noticeable to the naked eye, and in this example, the bottom is 250 μm and the height is four pixels. In this example, since one pixel is 1 mm square, four first colored layers 41 are arranged in one pixel.

When the first colored layer 41 is formed, a wedge-shaped color for correcting misalignment is formed on the black mask BM located between the column electrodes (transparent electrodes 5) on the bottom side in accordance with the width of the black mask BM. Preferably, a layer 411 is provided.
The height of the shift correction coloring layer 411 may be lower than that of the first coloring layer 41. Further, it is preferable that the misalignment correction coloring layer 411 has an angle equivalent to the triangular shape of the first coloring layer 41.

Next, a photosensitive resin in which a pigment exhibiting a light blue color is dispersed is applied on the first colored layer 41, and is exposed and developed using a predetermined photomask, thereby obtaining a structure shown in FIG.
As shown in the figure, the second wedge-shaped
The coloring layer 43 is formed. FIG. 5 shows the first colored layer 41 and the second colored layer 41.
Although the drawing is complicated because the coloring layer 43 is overwritten, the pattern shape of only the second coloring layer 43 is shown in FIG. 6 to facilitate comparison with the first coloring layer 41 in FIG. Show.

According to this example, the second colored layer 43 is formed of the first colored layer 43.
It does not have a shape that completely enters the wedge-shaped valley between the colored layers 41, 41, but has an overlapping portion with the first colored layer 41. That is, in this example, the range in which gradation is desired to be applied is a range from the height position of about half of the first colored layer 41 to the bottom, and therefore, the second colored layer 43
Covers the tip side portion of the first colored layer 41, and from the height position of about half of the first colored layer 41, the first colored layers 41, 4
A wedge-shaped pattern 431 that enters the wedge-shaped valley between the two is formed.

The second colored layer 43 is formed on the first colored layer 41.
7 is formed on the oblique side of the wedge-shaped pattern 431, as shown in the cross-sectional view of FIG.
, The deviation at the time of alignment can be allowed. The width of the overlapping portion L is preferably about 10 to 50 μm, although it depends on the alignment accuracy of the photomask.

When the transparent electrode 5 as a column electrode is formed on the colored layers 41 and 43, the overlapped portion L becomes a stepped portion and can be a factor such as a crack for the transparent electrode 5, but the overlapped portion L is transparent. Since it is substantially parallel to the direction in which the electrode 5 extends and does not cross the transparent electrode 5, even if a crack occurs in the transparent electrode 5, it does not lead to disconnection.

[0034]

Embodiment 1 First, an inner surface black in which a 10-character display portion in which a pixel opening portion is 1 mm square and a black mask width is 150 μm and 5 × 7 dots are one display unit, and an icon portion is mixed. A mask substrate was manufactured. Then, a blue color is formed at the lower part of 5 × 7 dots and a light blue color is formed at the upper part so that a boundary portion is overlapped in a wedge shape with a width of about 30 μm, and a gradation is applied. To form an inner color substrate. Thereafter, a transparent conductive film made of ITO was formed, the transparent electrode was patterned, and a cell was fabricated in combination with the counter substrate. As a negative TN device, a polarizing plate was stuck, a white backlight was installed, and driving was performed at 1/8 duty. As a result, good gradation was visually recognized.

[0035]

As described above, according to the present invention,
In performing gradation display by gradually changing the color tone of the display color in a predetermined display area along a specific direction,
By forming the first colored layer and the second colored layer colored with different translucent colors as a wedge-shaped engagement pattern,
Since a very high coloring position accuracy is not required, it is possible to cope with a simple photomask design, and the gradient of the gradation can be set freely.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view for explaining a basic mode of a liquid crystal display device according to the present invention.

FIG. 2 is a plan view showing a basic pattern of a coloring layer provided in the liquid crystal display element.

FIG. 3 is a plan view showing a modification of the coloring layer.

FIG. 4 is a plan view showing a first coloring layer formed on a substrate.

FIG. 5 is a plan view showing a state in which a second colored layer is formed on the first colored layer in FIG. 4;

FIG. 6 is a plan view showing only the second colored layer extracted from FIG. 5;

FIG. 7 is a sectional view of a wedge-shaped meshing pattern portion in FIG. 5;

[Explanation of symbols]

 Reference Signs List 1 liquid crystal display element 2 first electrode substrate 3 second electrode substrate 4 coloring layer 41 first coloring layer 411 misalignment correction coloring layer 43 second coloring layer 431 wedge-shaped pattern 5 transparent electrode (column electrode) 6 transparent electrode (row electrode) 7 Peripheral sealing material 8 Liquid crystal material BM Black mask D Pixel L Overlapping part

Continued on the front page F-term (reference) 2H048 AA01 AA05 AA12 AA18 AA22 AA25 AA29 2H091 FA02Y FA35Y FB12 FD04 FD05 FD06 LA30 5C094 AA08 AA32 AA43 AA48 BA43 CA19 CA23 DA13 EA04 EA05 EB02 ED02 FA01

Claims (6)

[Claims] 1. A display device comprising: a pair of electrode substrates bonded to each other with a liquid crystal layer interposed therebetween; a color layer provided on an inner surface of one of the electrode substrates; In a liquid crystal display device having a gradation display function in which a color tone gradually changes along a specific direction, a first colored layer colored with a different light-transmitting color is provided in the predetermined display region on the inner surface of the one electrode substrate. And a second colored layer, wherein each of the colored layers is formed as a wedge-shaped meshing pattern along the specific direction. 2. The first colored layer and the second colored layer both have a basic pattern, and one of the basic patterns is an upright triangular shape, while the other basic pattern is an inverted one. It is triangular and between their hypotenuses,
2. The liquid crystal display device according to claim 1, further comprising an overlapping portion having a predetermined width. 3. A first electrode serving as one of a row electrode or a column electrode is formed on the one electrode substrate side, and a second electrode serving as the other of the row electrode or the column electrode is formed on the other electrode substrate side.
Electrodes are formed, and a black mask defining a pixel is formed on one of the electrode substrates in a light-shielding manner, and a black mask defining one pixel is formed in a grid pattern. 3. The liquid crystal display device according to claim 1, wherein the liquid crystal display element extends in a direction in which one electrode extends. 4. The liquid crystal display device according to claim 3, wherein said wedge-shaped engagement pattern is formed over a plurality of said pixels. 5. The liquid crystal according to claim 3, wherein the first colored layer or the second colored layer is formed on a black mask provided between the first electrodes in accordance with the width of the mask. Display element. 6. The liquid crystal display device according to claim 1, wherein the coloring layer is formed by dispersing a pigment in a photosensitive resin.