JP2003108035A - Diffuse-reflective color display - Google Patents

Abstract

(57) [Problem] To provide a reflection type display capable of accurately and easily aligning a pixel with a color filter. SOLUTION: A first substrate having a plurality of active elements and electrodes corresponding to a plurality of pixels connected thereto, and a first substrate having a planar transparent electrode disposed to face the first substrate and facing the first substrate. And a display medium provided between the first and second substrates, wherein the voltage applied between the pixel electrode and the transparent electrode controls the scattered reflection state of the display medium. In the type color display,
A color filter comprising a plurality of colored layers having a predetermined pattern is formed on the display medium at a position corresponding to the electrode corresponding to the pixel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffuse reflection type color display having a color filter.

[0002]

2. Description of the Related Art A transmissive LCD (Liquid C) is provided with a back light on its back surface and its light emission is controlled by a liquid crystal panel.
In contrast to a vertical display, a reflective LCD that controls the reflected light of ambient lighting (ambient light) is mainly used for mobile information terminals because of its low power consumption and good visibility in direct sunlight. Is starting to appear. In addition, in recent years, a display utilizing a display principle different from that of an LCD has been reported, and is expected as a reflective display having a characteristic that the LCD does not have.

The display principle of the LCD is currently TN (Twi).
Steed Nematic) method and STN (Super)
Two methods, a twisted nematic method, are mainly used, and further IPS (In-Plane) is used.
Switching method, MVA (Multi-do)
main Vertical Alignment) method and OCB (Optical Compensa) method
The ted birefringence method has also been reported.

Each of these methods controls the transmission state of light by itself and cannot change the color. Therefore, it is necessary to use a color filter to display in color.

As another display method in place of the LCD, an electrophoretic method in which charged fine particles are moved by an electric field (Japanese Patent No. 2551785) and a twist ball method in which spherical bodies separately coated in two colors are rotated in the electric field (Patent No. 2860790), a polymer dispersed liquid crystal system (PDLC Polymer Dispersion) in which an alignment state inside liquid crystal droplets dispersed in a resin is controlled by an electric field.
Liquid Crystal (Japanese Patent Laid-Open No. 2001-9
2383), a polymer network type liquid crystal system (PNLC Polymer Network Li) in which the resin component ratio is small and the polymer has a network structure in the liquid crystal.
Quid Crystal) (Japanese Patent Laid-Open No. 2001-154)
219).

In all of these display systems, the scattered reflection state is controlled by an electric field, and it is difficult to display colors by themselves, so it is practical to use a color filter.

[0007]

In the case where the color filter is used for the display body of any of the methods described above, the substrate having the electrodes corresponding to a plurality of pixels and the substrate having the color filter are set. It is necessary to accurately align the positions of the pixels and the positions of the color filters and to bond them. The finer and more pixels to display, the higher the required alignment accuracy.

However, it is very difficult in process to bond the two substrates after aligning them, and it is also difficult to perform this process at high speed. Since high precision is also required for the apparatus used in this process, this is a factor that raises the cost in terms of both equipment investment and throughput.

Furthermore, in recent years, there has been an increasing tendency to change the substrate used from glass to a lighter, thinner, and more flexible resin. However, since resin has a larger amount of deformation due to temperature and stress than glass, it becomes more difficult to align and bond two substrates.

The present invention has been made under the above circumstances, and an object of the present invention is to provide a diffuse reflection type color display capable of accurately and easily aligning a pixel and a color filter.

[0011]

The inventors of the present invention have conducted extensive research to solve the above problems, and as a result, form a color filter directly on a display medium to form a color filter with high accuracy. It has been found that the bonding process is very easy because it is possible to do and the alignment is not taken into consideration when bonding the two substrates.
The present invention has been completed.

That is, according to the present invention, a first substrate having a plurality of active elements and electrodes corresponding to a plurality of pixels connected to these elements, and a first substrate, which is arranged to face the first substrate, are provided in a planar shape. A second substrate having a transparent electrode, and a display medium provided between the first and second substrates, wherein the voltage applied between the pixel electrode and the transparent electrode causes the scattering reflection state of the display medium. In the scattering reflection type color display body for controlling the above, the scattering reflection characterized in that a color filter composed of a plurality of colored layers having a predetermined pattern is formed at a position corresponding to the electrode corresponding to the pixel on the display medium. Provide a type color display.

Further, according to the present invention, there is provided a first substrate having a segment electrode, a second substrate arranged so as to face the first substrate and having a transparent electrode provided in a planar shape, and the first and the second substrates. A display medium provided between two substrates, wherein a scattering reflection type color display body for controlling a scattering reflection state of the display medium by a voltage applied between the segment electrode and the transparent electrode is provided on the display medium. (3) A scattering reflection type color display body, characterized in that a color filter comprising a plurality of colored layers having a predetermined pattern is formed at a position corresponding to the segment electrode.

In the scattering reflection type color display of the present invention, the color filter is formed directly on the display medium or, if the surface of the display medium has low flatness, it is formed via a flattening layer. Good. In this case, the planarization layer is transparent,
It is desirable that it has a good affinity with the dye or pigment constituting the microcapsules. Acrylic resin can be mentioned as a typical material of the flattening layer which is preferably used.

The formation of the color filter on the display medium is as follows.
Printing colored layers of multiple colors by screen printing,
It can be preferably performed by printing with an ink jet printer. As the plurality of colors, three colors of R, G, B or three colors of C, M, Y can be used.

The present invention can be applied to reflective displays such as electrophoretic reflective displays, twisted ball reflective displays, polymer dispersed liquid crystal reflective displays, and polymer network liquid crystal reflective displays. I can. Among these, the electrophoretic reflection display and the twist ball reflection display, which scatter and reflect on the surface of the display medium, are more preferable because the effect of parallax due to the cell thickness is not possible in principle. A microcapsule type electrophoretic display can be preferably used as the electrophoretic reflection type display.

In the scattering reflection type color display of the present invention, the electrode pattern can have various shapes corresponding to the pixels. It may also be a segment electrode. Also,
The scattering reflection type color display of the present invention can be applied regardless of the type of substrate such as a glass substrate, a resin substrate and a resin film. The present invention cannot be applied to the LCD such as the conventional TN and STN. This is because these display media are quasi liquids and it is impossible to provide a color filter on the surface thereof. On the other hand, the electrophoretic method, particularly the microcapsule type electrophoretic method, is suitable for the present invention because the medium itself is solid and the color filter can be easily formed directly on the medium.

In the scattered reflection type color display of the present invention constructed as described above, a color filter is formed in advance at a position corresponding to an electrode on the display medium of the first substrate before the two substrates are bonded together. As a result, both the electrode and the color filter are formed with high precision on the one substrate side. for that reason,
When the two substrates are bonded together, it is not necessary to perform alignment, that is, it is not necessary to perform the difficult work of bonding after alignment. Therefore, the manufacturing process is facilitated, a great improvement can be obtained, and it is possible to obtain a reflective color display provided with a color filter formed with high precision.

In particular, when the substrate is made of resin, which is a tendency in recent years, when the pixel and the color filter are formed on different substrates, the amount of deformation of resin due to temperature and stress is larger than that of glass. Although it is extremely difficult to align and bond a single substrate, the present invention does not require alignment, so that the bonding operation of the substrates is very easy. Further, even after the substrates are bonded together, the resin is deformed due to temperature and stress, so that
Although the positional relationship between the pixel and the color filter changes, such a problem does not occur in the present invention because the pixel and the color filter are integrally formed via the display medium.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically by showing Examples and Comparative Examples of the present invention as embodiments of the present invention. The present invention is not limited to these.

<Example 1> Titanium oxide particles having a particle size of 0.1 µm and carbon black particles having a particle size of 0.1 µm were dispersed in an organic solvent as white particles and black particles, respectively, to prepare a dispersion in urea resin. Then, microcapsules having a particle diameter of 100 μm were formed.

Then, as shown in FIG. 1A, on the pixel electrode 2 having a predetermined pattern formed on the glass substrate 1,
One layer of the above microcapsules was densely spread to form a microcapsule layer 3, which was used as a back substrate.

Next, on the microcapsule layer 3, a color filter 4 consisting of a stripe-shaped colored layer of three colors of R, G and B was formed on the pixel electrode 2 by an ink jet printer.
It was formed corresponding to.

On the other hand, as shown in FIG. 1B, ITO having a thickness of about 1000Å is formed as a transparent electrode on the glass substrate 5.
(Indium Tin Oxide) layer 6 is formed,
The front substrate was used.

The front substrate shown in FIG. 1 (b) and the rear substrate shown in FIG. 1 (a) were attached to each other to prepare a microcapsule type electrophoretic reflection type color display as shown in FIG. 1 (c).

In the reflection type color display thus obtained, the color filter 4 was accurately arranged at the position corresponding to the pixel electrode 2. Moreover, by applying a predetermined voltage between the electrodes, white, black, and
I was able to display red, blue, green, etc.

Example 2 On the microcapsule layer, a flattening layer made of acrylic resin and having a thickness of 1 μm is formed.
A microcapsule type electrophoretic reflection type display was prepared in the same manner as in Example 1 except that a colored layer was formed thereon.

In the reflective color display thus obtained, the color filter 4 was accurately arranged at the position corresponding to the pixel electrode 2, as in the first embodiment. Further, by applying a predetermined voltage between the electrodes, it was possible to display white, black, red, blue, green and the like with good image quality, as in Example 1.

Example 3 A microcapsule type electrophoretic reflection display was prepared in the same manner as in Example 1 except that a resin substrate was used instead of the glass substrate.

In the reflective color display thus obtained, the color filter 4 was accurately arranged at the position corresponding to the pixel electrode 2, as in the first embodiment. Further, by applying a predetermined voltage between the electrodes, it was possible to display white, black, red, blue, green and the like with good image quality, as in Example 1.

Further, although the reflective color display according to this example was deformed by temperature and stress, the positional relationship between the pixels and the color filter did not change.

Example 4 A microcapsule electrophoretic reflection display was prepared in the same manner as in Example 1 except that the color filter 4 was formed by screen printing.

In the reflection type color display thus obtained, the color filter 4 was accurately arranged at the position corresponding to the pixel electrode 2 as in the first embodiment. Further, by applying a predetermined voltage between the electrodes, it was possible to display white, black, red, blue, green and the like with good image quality, as in Example 1.

In the above embodiments, an example applied to a microcapsule type electrophoretic display has been described, but the present invention is a twist ball type reflective color display, a polymer dispersion type liquid crystal type reflective color display, a polymer. The same effect can be obtained by applying it to a reflective color display such as a network type liquid crystal reflective color display.

In the above embodiments, the colored layers forming the color filter are in contact with each other and are formed low, but it is also possible to form them at intervals of 1 to 20 μm. By doing this, the aperture ratio is increased,
A bright display screen can be obtained.

[0036]

As described above in detail, according to the present invention, a color filter is formed in advance on the display medium of the first substrate at a position corresponding to the electrode before the two substrates are bonded together. Therefore, when bonding both substrates, it is not necessary to perform alignment, that is, it is not necessary to perform the difficult work of bonding after alignment, and therefore, it is possible to significantly improve the manufacturing process, It is possible to obtain a reflective color display including a color filter formed with high precision.

[Brief description of drawings]

FIG. 1 is a sectional view showing a manufacturing process of a microcapsule type electrophoretic display according to a first embodiment in the order of steps.

[Explanation of symbols]

1,5 ... Glass substrate 2 ... Pixel electrode 3 ... Microcapsule layer 4 ... Color filter 6 ... Transparent electrode

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09F 9/35 G09F 9/35 9/37 9/37 Z F term (reference) 2H089 HA03 QA12 TA02 TA09 TA12 2H091 FA02Y FB02 FC12 FD04 GA02 GA13 JA02 LA12 LA15 5C094 AA08 AA43 BA48 BA75 BA76 BA93 CA19 CA24 DA13 EA04 EA05 EA07 EB02 ED03

Claims (7)

[Claims] 1. A first substrate having a plurality of active elements and electrodes corresponding to a plurality of pixels connected to the elements, and a transparent electrode disposed in a planar shape and facing the first substrate. Scattering comprising a second substrate and a display medium provided between the first and second substrates, and controlling scattering and reflection state of the display medium by a voltage applied between the pixel electrode and the transparent electrode. In the reflective color display, a color filter composed of a plurality of colored layers having a predetermined pattern is formed at a position corresponding to an electrode corresponding to the pixel on the display medium. . 2. A first substrate having a segment electrode, a second substrate arranged to face the first substrate and having a transparent electrode provided in a planar shape, and between the first and second substrates. And a display medium provided on the display medium, wherein the segment electrode on the display medium is a scattering reflection type color display for controlling the scattering reflection state of the display medium by a voltage applied between the segment electrode and the transparent electrode. 1. A scattering reflection type color display body, characterized in that a color filter comprising a plurality of colored layers having a predetermined pattern is formed at a position corresponding to. 3. The diffuse reflection color display according to claim 1, which is an electrophoretic display. 4. The scattering reflection type color display according to claim 1, which is a twist ball type display. 5. The scattering reflection type color display according to claim 1, which is a polymer dispersion type liquid crystal display. 6. The scattering reflection type color display according to claim 1, which is a polymer network type liquid crystal display. 7. The scattering reflection type color display according to claim 3, which is a microcapsule type electrophoretic display.