JP2003195362A - Electrophoretic display device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophoretic display device which can secure excellent visibility irrelevantly to the lightness in use environment. <P>SOLUTION: The electrophoretic display device 1 has an electronic ink layer 6 containing many white electrified particles 4 and many black electrified particles 5 between an upper substrate 3 and a lower substrate 2 and also has a transmission display area T and reflection display area R in one pixel constituting a display pattern. In the transmission display area T, white display and black display are switched according to whether white electrified particles 4 and black electrified particles 5 are present or not and in the reflection display area R, white display and black display are switched by attracting the white electrified particles 4 or black electrified particles 5 to the upper substrate 3. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophoretic display device and an electronic apparatus, and more particularly to a display device utilizing an electrophoretic phenomenon having good visibility regardless of a use environment.

[0002]

2. Description of the Related Art A phenomenon in which charged particles dispersed in a liquid migrate by applying an electric field and an electrophoretic phenomenon are well known. As an application of this electrophoretic phenomenon, when charged fine pigment particles are dispersed in a liquid colored with a dye, and this is sandwiched between a pair of electrodes and an electric field is applied, the charged particles are attracted to one of the electrodes. Are known, and attempts have been made to realize display devices with them. More specifically, the charged particles and the liquid have different colors, and for example, white charged particles are dispersed in a liquid containing a black dye. In addition, at least the electrode visually recognized by the user is a transparent electrode. Then, when white charged particles are attracted to the electrode on the side visually recognized by the user by applying an electric field, external light incident from the user side is reflected (scattered) by the layer composed of white particles, so that white color is presented and When the white charged particles are attracted to the electrode on the far side, the incident light is absorbed by the liquid layer containing the black dye, so that the electrode exhibits a black color. By controlling the movement of such charged particles for each pixel, a display pattern can be formed and information can be displayed.

However, the above electrophoretic display device is inferior in reliability in that the black dye in the liquid adheres to the periphery of the white particles due to long-term use, and the contrast gradually decreases. It was Further, if the gap between the electrodes is narrowed in order to reduce the driving voltage, incident light may not be completely absorbed in the liquid, which causes a problem that the contrast is lowered. Therefore, in order to solve these problems, two types of charged particles having different polarities of positive and negative and different colors, for example, white particles having a negative surface charge and black particles having a positive surface charge are used. An electrophoretic display device has been proposed in which charged particles of two colors are dispersed in a liquid and these charged particles are moved in opposite directions by an electric field. In this electrophoretic display device, when white charged particles are attracted to the electrode on the viewing side by an electric field in one direction, white is produced by the same action as described above, and the electrode on the viewing side is black by the electric field in the opposite direction. When the charged particles are attracted, the incident light is absorbed by the layer composed of the black particles, so that it exhibits a black color.

[0004]

In general, this type of electrophoretic display device can realize paper-white display (paper white) by utilizing the scattering of light by white particles, and has a wide viewing angle. It has advantages such as low power consumption and low cost. However, the electrophoretic display device basically performs display using outside light incident from the user side, that is, so-called reflective display, and transmissive display has not been proposed yet. . That is, the electrophoretic display device has a fundamental problem that it cannot be visually recognized in a dark place.

In the field of liquid crystal display devices, for example, reflection type display using outside light such as sunlight is used when used outdoors in bright places, while the back surface of a liquid crystal cell is used when used in dark places. A so-called "semi-transmissive reflection type" liquid crystal display device, which performs transmission type display using illumination light from a backlight provided in the above, has already been put into practical use. The transflective liquid crystal display device has the advantage that it can always ensure good visibility regardless of the brightness of the environment in which it is used and that it can save power consumption by turning off the backlight in bright places. In recent years, it has been favorably used in various portable electronic devices and the like. In this specification, a display device having both a reflective display mode and a transmissive display mode is referred to as a “semi-transmissive reflective type”.

On the other hand, the electrophoretic display device is expected to be applied to portable electronic devices and the like in the near future as a form of electronic paper having the advantages of both an electronic display and paper. However, it is a very important function that the device is installed in a portable electronic device and that good visibility is obtained in various usage environments. Against this background, it is desired to provide an electrophoretic display device having both a reflective display mode and a transmissive display mode.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electrophoretic display device capable of ensuring good visibility regardless of the brightness of the use environment. To do.

[0008]

In order to achieve the above object, the electrophoretic display device of the present invention has a first substrate between a first substrate and a second substrate, both of which have translucency. A translucent liquid containing a plurality of first charged particles of a first color having a polarity is sandwiched, and an illumination means is provided on the outer surface side of the first substrate to form a display pattern. A transmissive display region and a reflective display region in one unit region, wherein the first charged particles are excluded from the transmissive display region in the transmissive display region, and the transmissive display region is reflected from the first substrate side. Illumination light from the illumination means is transmitted to the second substrate side, the color of the illumination light is visible, and the first charged particles are adsorbed to the second substrate in the reflective display area. By doing so, the first color of the first charged particles becomes Characterized in that it is the authorized capacity.

Further, in addition to the first charged particles, the liquid has a plurality of second colors different from the first color charged to a second polarity opposite to the first polarity. The second charged particles are contained, and at least one of the first charged particles and the second charged particles is present in the transmissive display area to absorb the illumination light. Alternatively, reflection occurs to block the transmission of the illumination light from the first substrate side to the second substrate side, and the second charged particles are transferred to the second substrate in the reflective display area. By being adsorbed, the second
It is desirable that the second color of the charged particles is visible.

The inventor of the present invention, for example, corresponds to one segment in the case of a segment type display device and one pixel in the case of a matrix type display device. Electrophoresis capable of both transmissive display and reflective display by providing both a reflective display area and a reflective display area, and controlling the movement of charged particles in each display area by changing the electric field application state in the transmissive display area and reflective display area. It has been found that a display device can be realized.

That is, the display principle of the electrophoretic display device of the present invention is as follows. When displaying an arbitrary color (for example, white) in one unit area, in the transmissive display area, the state of the electric field is controlled so that the first charged particles are excluded from this area, and from the first substrate side. When the illumination light (for example, white light) from the illumination means is transmitted to the second substrate side, the user visually recognizes the display in the color of the illumination light in the transmissive display mode when the user views the device from the second substrate side. can do. At this time, in the reflective display area, if the state of the electric field is controlled so that the first charged particles are attracted to the second substrate side, the eyes of the user on the second substrate side will see the first charged particles. Therefore, if the color of the first charged particles is set to, for example, white, white display can be visually recognized. In this way, the display can be performed.

Strictly speaking, even if the same white is used, the white of the illuminating light and the white of the charged particles are different, so the display color depends on the presence / absence of external light, lighting of the lighting means, and non-lighting. Is slightly different. On the contrary, it is also possible to positively utilize the difference between the color of the illumination light and the color of the particles. For example, when considering using a transflective electrophoretic display device mainly in the future reflection mode, It is also possible to use the color of the illumination light to adjust the display color in the display area.

Next, assuming an electrophoretic display device in which charged particles of two colors having different polarities and colors of surface charges are dispersed in a liquid, the other color display is possible. That is, when displaying a color (for example, black) different from the previous description in one unit area, at least one of the first charged particle and the second charged particle exists in this area in the transmissive display area. The electric field is controlled in such a manner that the illumination light is absorbed by either one of these charged particles, or the illumination light is reflected again to the first substrate side. If the transmission of illumination light (for example, white light) is blocked, the color of the illumination light cannot be visually recognized by the user, and the user perceives it to be black in the transmission mode. At this time, if the state of the electric field is controlled so that the second charged particles are attracted to the second substrate side in the reflective display area, the user's eyes will see the color of the second charged particles. By setting the color of the second charged particles to black, for example, black display can be visually recognized.

As described above, according to the electrophoretic display device of the present invention, the same color display can be visually recognized in both the reflective display mode and the transmissive display mode within one unit area constituting the display pattern. Therefore, it is possible to function as a so-called transflective display device, and it is possible to realize an electrophoretic display device having good visibility regardless of the brightness of the usage environment.

As a method of applying an electric field to each display region in the electrophoretic display device of the present invention, for example, in the reflective display region, the first substrate and the second substrate are provided in the reflective display region.
An electric field in the opposite direction is switchably applied to the first substrate and the second substrate in the transmissive display area.
It is desirable that the intermediate potential between the voltage of the first substrate and the voltage of the second substrate is applied to either one of the substrates.

According to the above structure, when focusing on the reflective display area, for example, when the voltage of the second polarity is applied to the second substrate, the first charged particles having the charge of the first polarity become the first charged particles. The second color is attracted to the second substrate side, so that the first color is visually recognized, and when the voltage of the first polarity is applied to the second substrate, the second charged particles having the charges of the second polarity become the second charged particles. The second color is visually recognized because it is attracted to the substrate side of. Focusing on the transmissive display region, for example, in the state where an intermediate potential between the voltage of the first polarity and the voltage of the second polarity is applied to the second substrate, each charged particle is changed depending on the voltage application state on the reflective display region side. Are all attracted to one of the substrates on the reflective display region side and eliminated from the transmissive display region, or one of the first and second charged particles is attached to the first substrate or the second substrate. It will either be attracted. Therefore, in the former state, the color of the illumination light can be visually recognized, and in the latter state, the illumination light is absorbed or reflected and the illumination light is blocked. By adopting such an electric field application method, the electrophoretic display device of the present invention based on the above display principle can be realized.

As a concrete electrode configuration, electrodes made of a transparent conductive film are provided on each of the first substrate and the second substrate in the reflective display region, and in the transmissive display region, the first substrate and the second substrate. It is desirable to provide an electrode made of a transparent conductive film on either one of the substrates. According to this configuration, it is possible to realize the above-described electric field applying method with the simplest electrode configuration.

When the electrophoretic display device of the present invention described above is expressed using another expression, a first substrate charged with a first polarity is provided between a first substrate and a second substrate which both have translucency. A plurality of first charged particles of one color and a plurality of second charged particles of a second color different from the first color and charged to a second polarity opposite to the first polarity And a illuminating means is provided on the outer surface side of the first substrate, and a transmissive display region and a reflective display region are formed in one unit region constituting the display pattern. In the transmissive display area, switching between transmission and blocking of illumination light is performed depending on the presence or absence of the first charged particles and the second charged particles, and in the reflective display area, the first charged particles and the second charged particles are switched. Make the first color visible depending on which is adsorbed to the second substrate Wherein the switching whether to visually recognize the second color.

That is, the electrophoretic display device of the present invention is
In the transmissive display area, the display color is switched depending on whether the illuminating light is transmitted through the liquid having a light-transmitting property when the charged particles are not present or the illuminating light is blocked when the charged particles are present. It can be said that the display color is switched according to the display principle of the conventional electrophoretic display device using colored charged particles.

As the first color and the second color used as the colors of the first and second charged particles, any color can be selected as long as the charged particles can be colored, but the first color The simplest method is to use white as the second color and black as the second color. With this configuration, it is possible to use an illuminating device equipped with an ordinary light source such as a cold cathode tube that emits white light and an LED as an illuminating means, and it is possible to color charged particles without any problem, and display in black and white. Can be easily realized.

In addition, for example, even if red is used as the first color and black is used as the second color, if red is used as the color of the illumination light,
Similar to the display principle of the present invention, two-color display is possible. However, when a color other than black is used as the second color, such as white as the first color and red as the second color, red display can be visually recognized in the reflective display area (reflection mode).
Since only the illumination light is blocked in the transmissive display area (transmissive mode), red display cannot be realized, and the user feels black display. In this case, the color balance between the reflective mode and the transmissive mode is significantly disturbed, but the display is temporarily possible.

An electronic apparatus of the present invention is characterized by including the electrophoretic display device of the present invention. According to the present invention, it is possible to realize an electronic device including a display unit having good visibility regardless of the usage environment.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. The electrophoretic display device according to the present embodiment includes a thin film transistor (Thin Film Transistor) as a switching element.
Hereinafter, this is an example of an active matrix type electrophoretic display device using a TFT (abbreviated as TFT). 1 is a plan view showing an upper substrate constituting the electrophoretic display device of the present embodiment, FIG. 2 is a sectional view taken along the line AA ′ of FIG. 1, and the electrophoretic display device of the present embodiment is shown. 3 is a diagram for explaining the display principle of FIG.

As shown in FIG. 2, the electrophoretic display device 1 of the present embodiment has a lower substrate 2 (first substrate) and an upper substrate 3 (second substrate) made of a light-transmissive base material such as glass. (The substrate of), white (first color) negatively charged (first polarity)
A large number of charged particles 4 (first charged particles) and a large number of black (second color) charged particles 5 that are positively (second polarity) charged.
A light transmissive liquid layer 6 in which (second charged particles) are dispersed is sandwiched. For example, TiO ₂ is used as the core of the charged particles, and a coating layer of polyethylene or the like colored in white or black is formed around the TiO ₂ . As the dispersion medium for dispersing the charged particles, for example, a mixed solution of ethylene tetrachloride and isoparaffin is used. The liquid layer 6 containing the charged particles 4 and 5 will be described below.
It is called an electronic ink layer.

As shown in FIG. 1, the upper substrate 3 has a structure in which a plurality of data lines 8 and a plurality of scanning lines 9 are arranged in a grid pattern.
An area surrounded by the adjacent data lines 8 and the adjacent scanning lines 9 becomes one pixel 10 (unit area) that constitutes a display pattern such as a character or a picture. A substantially rectangular first electrode 11 is formed in one pixel 10, and the first electrode 11
A rectangular opening 11a is provided inside the opening 1.
A second electrode 12 is formed inside 1a. A TFT 15 electrically connected to the data line 8 and the scanning line 9 is formed at the lower right of the pixel 10 in FIG.
T15 controls the voltage applied to the first electrode 11. Similarly, the TFT 1 is provided at the lower left of the pixel 10 in FIG.
6 is formed, and this TFT 16 is connected to the second electrode 12
The voltage applied to is controlled. With this configuration, the first
The electrode 11 and the second electrode 12 can be electrically independently driven.

On the upper surface of the lower substrate 2, a third electrode 13 is formed over a plurality of pixels 10, and the first electrode 1
It overlaps with 1. Therefore, the third electrode 13 is also provided with the opening 13a similar to the first electrode 11, but unlike the upper substrate 3 side, no electrode is formed inside the opening 13a. That is, the lower substrate 2 does not have a TFT, and a fixed potential is always applied to the third electrode 13.

Among the above-mentioned components, the data line 8, the scanning line 9, the TFTs 15 and 16 and the like are metal films having no translucency,
Although it may be formed of a silicon film or the like, the first to third electrodes 11, 12, and 13 are made of, for example, ITO (Indium T
in Oxide).

That is, looking at the sectional structure, as shown in FIG. 2, the first electrode 11 on the upper substrate 3 side and the third electrode 13 on the lower substrate 2 side face each other with the electronic ink layer 6 in between. Cage,
The second electrode 12 on the upper substrate 3 side does not face other electrodes. In the case of the present embodiment, in one pixel 10,
A region where the first electrode 11 on the upper substrate 3 side and the third electrode 13 on the lower substrate 2 face each other is a reflective display region R, and a region where only the second electrode 12 exists is a transmissive display region T. As shown in FIG. 1, the transmissive display area T within one pixel 10
Is formed sufficiently smaller than the area of the reflective display region R. The size of the transmissive display area T (the side on the shorter side) is determined by the gap between the upper and lower substrates 2 and 3 (electronic ink layer 6).
It is desirable that the width is smaller than the layer thickness) of the upper and lower substrates.
Is preferably about 10 μm. The reason will be described later.

Further, on the outer surface side of the lower substrate 2, there is provided a backlight 22 (illumination means) having a normal light source such as a cold cathode tube for emitting white light and an LED.

The display principle of the electrophoretic display device 1 of the present embodiment having the above structure will be described with reference to FIGS. 2 (a) and 2 (b). Here, the user views the display from the upper side of the upper substrate 3.

First, the first electrode 11 on the upper substrate 3 side
A predetermined voltage (hereinafter referred to as V1) is applied to the lower substrate 2
A predetermined voltage (hereinafter referred to as V2) to the third electrode 13 on the side
Is applied, and an intermediate potential between V1 and V2 is applied to the second electrode 12 on the upper substrate 3 side. At this time, V1 and V2
From this relationship, it is assumed that the electric field is directed from the first electrode 11 to the third electrode 13. Each electrode 11,1
When voltage is applied to Nos. 2 and 13 in this way,
As shown in (a), the white charged particles 4 are attracted to the first electrode 11 on the upper substrate 3 side, and the black charged particles 5 are attracted to the third electrode 13 on the lower substrate 2 side, while the upper substrate 3
Neither charged particle can be attracted to the second electrode 12 on the side.

Therefore, in the transparent display area T,
Since neither charged particle is present, the backlight 22
The white light L1 emitted from the electronic ink layer 6 and the second electrode 1 is neither absorbed nor scattered.
2. It passes through the upper substrate 3 and reaches the eyes of the user. Also,
In the reflective display region R, the white light L1 emitted from the backlight 22 is absorbed by the large number of black charged particles 5 on the third electrode 13, while sunlight, illumination light, etc. incident from the upper side of the upper substrate 3. Ambient light L2 is scattered by the large number of white charged particles 4 on the first electrode 11 and reaches the eyes of the user. Due to these effects, both the transmissive display region T and the reflective display region R are in the "white display" state in the above voltage applied state.

Next, the direction of the electric field is reversed between the first electrode 11 on the upper substrate 3 side and the third electrode 13 on the lower substrate 2 side, that is, a voltage different from that on the first electrode 11 ,
V3) is applied and the third electrode 13 is fixed at V2. At this time, from the relationship between V3 and V2, it is assumed that the direction of the electric field is the direction from the third electrode 13 to the first electrode 11. Then, the second electrode 1 on the upper substrate 3 side
The same potential V3 as that of the first electrode 11 on the same substrate is applied to 2. When the voltage is applied to each of the electrodes 11, 12, and 13 in this way, the black charged particles 5 are generated on the first electrode 11 and the second electrode 12 on the upper substrate 3 side, as shown in FIG. 2B. The white charged particles 4 are attracted to the third electrode 13 on the lower substrate 2 side.

Therefore, in the transparent display area T,
The white light L1 emitted from the backlight 22 is absorbed by the large number of black charged particles 5 on the second electrode 12, and therefore does not reach the eyes of the user. In the reflective display region R, the white light L1 emitted from the backlight 22 is reflected (scattered) by the large number of white charged particles 4 on the third electrode 13 and returns to the outer surface side of the lower substrate 2 again. The external light L2 incident from the upper side of the upper substrate 3 is absorbed by the large number of black charged particles 5 on the first electrode 11, and none of the light reaches the eyes of the user. Due to these effects, both the transmissive display region T and the reflective display region R are in the "black display" state in the above voltage applied state.

When the display color is switched from the "white display" state shown in FIG. 2 (a) to the "black display" state shown in FIG. 2 (b), the reflection display area R is in the "white display" state. The black charged particles 5 attracted to the inside of the transmissive display area T (second
It is necessary to diffuse so as to spread to the electrode 12 side). In this case, if the area of the transmissive display region T is too large, it is considered that the black charged particles 5 do not spread over the entire surface of the transmissive display region T, in which case the contrast is lowered. For this reason, it is desirable that the size of the transmissive display area T be small to some extent.

As described above, according to the electrophoretic display device 1 of the present embodiment, the same color display is visually recognized in both the reflective display mode and the transmissive display mode within one pixel 10 forming the display pattern. Therefore, it can function as a so-called transflective display device.
Therefore, in a dark place, the backlight 22 can be turned on and the display can be viewed mainly in the transmissive display mode. In a bright place, the backlight 22 can be turned off and the display can be viewed in the reflective display mode by external light. Therefore, an electrophoretic display device having good visibility can be realized.

[Second Embodiment] The second embodiment of the present invention will be described below.
The embodiment will be described with reference to FIG. FIG. 3 is a sectional view corresponding to FIG. 2 of the first embodiment, and is also a diagram for explaining the display principle of the electrophoretic display device of the present embodiment. The basic configuration of the electrophoretic display device of this embodiment is the same as that of the first embodiment, and the only difference is the position of the electrode in the transmissive display region. Therefore, in FIG. 3, the same components as those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the first embodiment, the electrode is provided on the upper substrate side in the transmissive display area, whereas in the present embodiment, the electrode is provided on the lower substrate side in the transmissive display area. That is, the electrophoretic display device 30 according to the present embodiment is similar to that shown in FIG.
As shown in (a) and (b), the first electrode 31 is provided in the reflective display region R on the lower substrate 2 side, and the second electrode 3 is provided in the transmissive display region T.
2 are provided, and the third electrode 33 is provided in the reflective display region T on the upper substrate 3 side. Therefore, in the present embodiment, contrary to the first embodiment, the pattern shown in FIG. 1 may be considered as the lower substrate 2.
The other configuration is exactly the same as that of the first embodiment.

The display principle of the electrophoretic display device 30 of the present embodiment having the above structure will be described with reference to FIGS. 3 (a) and 3 (b). However, as is clear from the figure, the movement and action of each charged particle in the reflective display area T is as shown in FIG.
Since there is no difference from the first embodiment shown in (b),
Only the transparent display area T will be described.

First, the first electrode 31 on the lower substrate 2 side
Is applied to the third electrode 33 on the upper substrate 3 side, and V2 is applied to the second electrode 12 on the lower substrate 2 side.
When an intermediate potential between 1 and V2 is applied, as shown in FIG. 3A, neither of the charged particles is attracted to the second electrode 32 on the lower substrate 2 side. Therefore, in the transmissive display area T, the white light L from the backlight 22 is emitted.
No. 1 is not absorbed or scattered and sequentially passes through the second electrode 32, the electronic ink layer 6, and the upper substrate 3 to reach the eyes of the user.
As a result, in the voltage applied state as described above, both the transmissive display region T and the reflective display region R are in the “white display” state.

Next, V3 is applied to the first electrode 31 on the lower substrate 2 side.
And the third electrode 33 on the upper substrate 3 side is kept at V2 while the potential is fixed, and the same V3 as the first electrode 31 is applied to the second electrode 32 on the lower substrate 2 side. . When the voltage is applied to each of the electrodes 31, 32 and 33 in this way, as shown in FIG. 3B, the second electrode 32 on the lower substrate 2 side, together with the first electrode 31, the white charged particles 4 are charged. Is attracted. Therefore, in the transmissive display area T, the white light L1 emitted from the backlight 22 is reflected (scattered) by the large number of white charged particles 4 on the second electrode 32 and returns to the outer surface side of the lower substrate 2 again. It does not reach the eyes of the user. Thus, in the voltage applied state as described above, the transmissive display region T and the reflective display region R are
Both are in the "black display" state.

As described above, also in the electrophoretic display device 30 of the present embodiment, the same color display can be visually recognized in both the reflective display mode and the transmissive display mode within one pixel 10 forming the display pattern. As in the first embodiment, it is possible to realize an electrophoretic display device having good visibility irrespective of the brightness of the use environment because it can function as a transflective display device. The effect of can be obtained.

[Electronic Equipment] Next, specific examples of electronic equipment provided with the electrophoretic display device according to the above-described embodiment of the present invention will be described. FIG. 4 is a perspective view showing an example of a mobile phone. In FIG. 4, reference numeral 1000 indicates a mobile phone main body, and reference numeral 1001 indicates a display unit using the electrophoretic display device.

FIG. 5 is a perspective view showing an example of a wrist watch type electronic device. In FIG. 5, reference numeral 1100 indicates a watch body, and reference numeral 1101 indicates a display unit using the electrophoretic display device.

FIG. 6 is a perspective view showing an example of a portable information processing device such as a word processor and a personal computer. In FIG. 6, reference numeral 1200 is an information processing apparatus, reference numeral 1202 is an input unit such as a keyboard, reference numeral 1204 is the information processing apparatus main body, and reference numeral 1206 is a display unit using the electrophoretic display device.

Since the electronic devices shown in FIGS. 4 to 6 are provided with the display section using the electrophoretic display device of the above-described embodiment, an electronic device having good visibility can be realized regardless of the use environment. can do.

The technical scope of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the upper substrate in the transmissive display area,
Although an example in which an electrode is provided on only one of the lower substrates is shown, even if electrodes are provided on both substrates, white display is performed when both electrodes are at an intermediate potential, as in the above embodiment. If the electrode of is set to the same potential as the electrode of the reflective display area on each substrate, black display is performed, and the display color can be switched. Further, in the present invention, it has been stated that, when white display is realized in the transmissive display area, no charged particles are present, but if a slight decrease in contrast is allowed, slightly charged particles are present. Good. Alternatively, the light may be scattered by slightly allowing the charged particles to exist.

Further, in the above-mentioned embodiment, the example in which the present invention is applied to the active matrix type device using the TFT for the switching element is shown. However, the active matrix using the thin film diode (TFD) for the switching element. The present invention can be applied to a mold device or a passive matrix device. In addition, other combinations of the color of the charged particles and the color of the illumination light of the backlight described in the above embodiment are possible as described in the section [Means for solving the problem]. Also,
The specific description of the material, size, shape, etc. of each component can be changed as appropriate.

[0049]

As described above in detail, according to the present invention, it is possible to function as a semi-transmissive reflection type display device, and an electric display device having good visibility regardless of the brightness of a use environment. Since the electrophoretic display device can be realized, the electrophoretic display device is suitable for application to, for example, portable electronic devices.

[Brief description of drawings]

FIG. 1 is a plan view showing an upper substrate that constitutes an electrophoretic display device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1, illustrating the display principle of the electrophoretic display device according to the present embodiment.

FIG. 3 is a cross-sectional view showing an electrophoretic display device according to a second embodiment of the present invention, which is a diagram for explaining a display principle of the electrophoretic display device according to the present embodiment.

FIG. 4 is a perspective view showing an example of an electronic device according to the present invention.

FIG. 5 is a perspective view showing another example of an electronic device according to the present invention.

FIG. 6 is a perspective view showing still another example of an electronic device according to the present invention.

[Explanation of symbols]

1,30 Electrophoretic display device 2 Lower substrate (first substrate) 3 Upper substrate (second substrate) 4 White charged particles (first charged particles) 5 Black charged particles (second charged particles) 6 Electronic ink layer 10 pixels (unit area) 11,31 First electrode 12,32 Second electrode 13,33 Third electrode 22 Backlight (illumination means)

Claims (7)

[Claims] 1. A first substrate and a second substrate both of which are transparent.
A transparent liquid containing a plurality of first charged particles of a first color charged with a first polarity is sandwiched between the first substrate and the substrate and the outer surface of the first substrate. Illumination means is provided, and a transmissive display area and a reflective display area are provided in one unit area that constitutes a display pattern, and the first charged particles are excluded from the transmissive display area in the transmissive display area. As a result, the illumination light from the illumination means is transmitted from the first substrate side to the second substrate side, the color of the illumination light is visible, and at the same time in the reflective display area, the first An electrophoretic display device, wherein the first color of the first charged particles is made visible by adhering the charged particles to the second substrate. 2. The liquid, in addition to the first charged particles, has a plurality of second colors different from the first color charged to a second polarity opposite to the first polarity. The second charged particles are contained, and at least one of the first charged particles and the second charged particles is present in the transmissive display area to absorb the illumination light. Alternatively, reflection occurs to block the transmission of the illumination light from the first substrate side to the second substrate side, and the second charged particles are transferred to the second substrate in the reflective display area. The electrophoretic display device according to claim 1, wherein the second color of the second charged particles is made visible by being adsorbed. 3. In the reflective display area, the first
A reverse electric field is switchably applied between the first substrate and the second substrate, and in the transmissive display region, either the first substrate or the second substrate is applied. The electrophoretic display device according to claim 2, wherein an intermediate potential between the voltage of the first substrate and the voltage of the second substrate is applied. 4. An electrode made of a transparent conductive film is provided on each of the first substrate and the second substrate in the reflective display region, and the first substrate and the second substrate are provided in the transmissive display region. The electrophoretic display device according to claim 3, wherein an electrode made of a transparent conductive film is provided on one of the substrates. 5. A first substrate and a second substrate both of which are transparent.
A plurality of first charged particles of a first color charged to a first polarity, and a second polarity opposite to the first polarity.
A liquid having a light-transmitting property, which contains a plurality of second charged particles of a second color different from the first color charged to the polarity, is sandwiched, and is attached to the outer surface side of the first substrate. Illumination means is provided, and a transmissive display region and a reflective display region are provided in one unit region forming a display pattern, and the presence or absence of the first charged particles and the second charged particles in the transmissive display region. The illumination light from the illuminating means is switched between transmission and blocking by the illuminating means, and in the reflective display area, either the first charged particle or the second charged particle is changed to the second charged particle.
The electrophoretic display device is switched between visually recognizing the first color and visually observing the second color depending on whether the substrate is adsorbed to the substrate. 6. The electrophoretic display device according to claim 1, wherein the first color is white and the second color is black. 7. An electronic apparatus comprising the electrophoretic display device according to claim 1. Description: