JP4211255B2 - Electrophoretic display device and electronic apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophoretic display device and an electronic apparatus, and more particularly to a display device using an electrophoretic phenomenon having good visibility regardless of a use environment.
[0002]
[Prior art]
A phenomenon in which charged particles dispersed in a liquid migrate by applying an electric field, and an electrophoresis phenomenon are well known. As an application of this electrophoresis phenomenon, when charged pigment fine particles are dispersed in a liquid colored with a dye, sandwiched between a pair of electrodes and an electric field is applied, the charged particles are attracted to one of the electrodes. Has been known, and attempts have been made to realize a display device with this. More specifically, the charged particles and the liquid have different colors. For example, white charged particles are dispersed in a liquid containing a black dye. Moreover, at least the electrode on the side visually recognized by the user is a transparent electrode. And when white charged particles are attracted to the electrode on the side visually recognized by the user by applying an electric field, the external light incident from the user side is reflected (scattered) by the layer made of white particles. When white charged particles are attracted to the far-side electrode, the incident light is absorbed by the liquid layer containing the black dye, and thus black. By controlling the movement of the charged particles for each pixel, a display pattern can be formed and information can be displayed.
[0003]
However, the electrophoretic display device is inferior in reliability in that the black dye in the liquid adheres to the periphery of the white particles when used for a long time, and the contrast gradually decreases. Further, if the gap between the electrodes is narrowed in order to reduce the driving voltage, the 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 positive or negative polarity and different colors, such as white particles having a negative surface charge and black particles having a positive surface charge, are used. There has been proposed an electrophoretic display device 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 viewing-side electrode by the electric field in one direction, white is exhibited by the same action as described above, and black is applied to the viewing-side electrode by the electric field in the reverse direction. When the charged particles are attracted, the incident light is absorbed by the layer made of black particles, and thus exhibits a black color.
[0004]
[Problems to be solved by the invention]
In general, this type of electrophoretic display device can realize white display (paper white) like paper by utilizing light scattering by white particles, wide viewing angle, low power consumption and low cost. It has the advantage of being able to plan. However, the electrophoretic display device basically performs a display using external light incident from the user side, that is, a so-called reflective display, and a display that performs a transmissive display has not been proposed yet. . That is, the electrophoretic display device has a fundamental problem that it cannot be seen in a dark place.
[0005]
For example, in the field of liquid crystal display devices, a reflective display that uses external light such as sunlight is used when used outdoors in a bright environment, while the back of the liquid crystal cell is provided when used in a dark place. A so-called “semi-transmissive reflection type” liquid crystal display device that performs transmissive display using illumination light from a backlight has already been put into practical use. The transflective liquid crystal display device has the advantage that it can always maintain good visibility regardless of the brightness of the usage environment and can save power by turning off the backlight in bright places. In recent years, it has been suitably used for various portable electronic devices and the like. In this specification, a display device having both the reflective display mode and the transmissive display mode is referred to as a “semi-transmissive reflective type”.
[0006]
On the other hand, electrophoretic display devices are also expected to be applied to portable electronic devices and the like in the near future as a form of electronic paper that combines the advantages of electronic display and paper. However, as long as it is mounted on a portable electronic device, it is an extremely important function to obtain good visibility in various usage environments. Under such a background, it is desired to provide an electrophoretic display device that has both a reflective display mode and a transmissive display mode.
[0007]
The present invention has been made to solve the above-described problems, and an object thereof is to provide an electrophoretic display device capable of ensuring good visibility regardless of the brightness of the use environment.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an electrophoretic display device of the present invention has a first color charged to a first polarity between a first substrate and a second substrate both having translucency. A translucent liquid containing a plurality of first charged particles is sandwiched, and an illuminating unit is provided on the outer surface side of the first substrate, so that a transmissive display is provided in one unit area constituting the display pattern. The illumination means from the first substrate side to the second substrate side by removing the first charged particles from the transmissive display region in the transmissive display region. And the first charged particles are adsorbed on the second substrate in the reflective display area, whereby the first charged particles are adsorbed on the second substrate. The first color of the charged particles is made visible. That.
[0009]
Further, in addition to the first charged particles, the liquid has a plurality of second colors of a second color different from the first color charged to a second polarity opposite to the first polarity. In the transmissive display region, at least one of the first charged particles and the second charged particles is present in the transmissive display region, so that the illumination light is absorbed or reflected. As a result, transmission of the illumination light from the first substrate side to the second substrate side is blocked, and the second charged particles are adsorbed on the second substrate in the reflective display region. Accordingly, it is desirable that the second color of the second charged particles be visible.
[0010]
The present inventor, 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, and a transmissive display region and a reflective display in “one unit region” constituting a display pattern. An electrophoretic display device capable of both transmissive display and reflective display by providing both regions and changing the electric field application state in the transmissive display region and reflective display region to control the movement of charged particles for each display region. I found out what could be achieved.
[0011]
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 region, the state of the electric field is controlled so that the first charged particles are excluded from this region in the transmissive display region, and from the first substrate side. When illumination light (for example, white light) from the illumination means is transmitted to the second substrate side, if the user views the device from the second substrate side, the display by the color of the illumination light in the transmissive display mode is visually recognized. can do. At this time, in the reflective display area, when the state of the electric field is controlled so that the first charged particles are adsorbed to the second substrate side, the user's eyes on the second substrate side have the first charged particles. Therefore, if the color of the first charged particles is set to, for example, white, the white display can be visually recognized. In this way, display can be performed.
[0012]
Strictly speaking, the white color of the illumination light is different from the white of the charged particles even if they are the same white. Therefore, the display color is slightly different depending on the presence / absence of external light, the lighting means on / off, etc. . Conversely, it may be possible to actively use 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 reflection mode in the future, It is also conceivable to use the color of the illumination light for adjusting the display color in the display area.
[0013]
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 region, at least one of the first charged particles and the second charged particles exists in this region in the transmissive display region. In this way, the electric field is controlled so that the illumination light is absorbed by one of these charged particles, or the illumination light is reflected again to the first substrate side, from the first substrate to the second substrate. If the transmission of the illumination light (for example, white light) is blocked, the color of the illumination light cannot be visually recognized by the user, and the user feels black when viewed in the transmission mode. At this time, if the state of the electric field is controlled so that the second charged particles are adsorbed on the second substrate side in the reflective display area, the user's eyes will see the color of the second charged particles. If the color of the second charged particles is black, for example, the black display can be visually recognized.
[0014]
Thus, 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 in one unit area constituting the display pattern, so-called An electrophoretic display device that can function as a transflective display device and has good visibility regardless of the brightness of the use environment can be realized.
[0015]
As an electric field application method for each display region in the electrophoretic display device of the present invention, for example, in the reflective display region, the electric field in the reverse direction is switched between the first substrate and the second substrate in the reflective display region. The intermediate potential between the voltage of the first substrate and the voltage of the second substrate is applied to either the first substrate or the second substrate in the transmissive display region. It is desirable to have a configuration.
[0016]
According to the above configuration, when focusing on the reflective display region, for example, in a state where a voltage of the second polarity is applied to the second substrate, the first charged particles having the charge of the first polarity are the second substrate. Since the first color is visually recognized and the voltage of the first polarity is applied to the second substrate, the second charged particles having the charge of the second polarity are attracted to the second substrate side. As a result, the second color is visually recognized. Focusing on the transmissive display area, for example, in a 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 depends on the voltage application state on the reflective display area side. Are all attracted to one of the substrates on the reflective display region side and excluded from the transmissive display region, or one of the first and second charged particles is placed on the first substrate or the second substrate. One of the states will 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.
[0017]
As a specific electrode configuration, 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 either the first substrate or the second substrate is provided in the transmissive display region. It is desirable to provide an electrode made of a transparent conductive film on one of them. According to this configuration, the above-described electric field application method can be realized with the simplest electrode configuration.
[0018]
When the electrophoretic display device of the present invention described above is expressed using another expression, the first color charged with the first polarity between the first substrate and the second substrate both having translucency is used. And a plurality of second charged particles of a second color different from the first color charged to a second polarity opposite to the first polarity. In addition, the light-transmitting liquid is sandwiched, the illumination means is provided on the outer surface side of the first substrate, and has a transmission display area and a reflection display area in one unit area constituting the display pattern, In the transmissive display area, the transmission and blocking of the illumination light are switched depending on the presence or absence of the first charged particle and the second charged particle, and in the reflective display area, either the first charged particle or the second charged particle is changed. The first color can be visually recognized or the second color can be Wherein the switching whether to sure.
[0019]
That is, the electrophoretic display device of the present invention transmits illumination light through a light-transmitting liquid in a state where charged particles are not present in the transmissive display region, or blocks illumination light in a state where charged particles are present. Thus, it can be said that the display color is switched according to the display principle of the conventional electrophoretic display device using charged particles of two colors in the reflective display region.
[0020]
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. It is easiest to use black as the second color.
If it is this structure, while being able to use the illuminating device provided with normal light sources, such as a cold-cathode tube and LED which radiate | emits white light as an illumination means, coloring of a charged particle can also be performed without a problem, and a monochrome display Can be easily realized.
[0021]
In addition, for example, even when red is used as the first color and black is used as the second color, two colors can be displayed in the same manner as in the display principle of the present invention as long as red is used as the color of the illumination light. 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, a red display can be visually recognized in the reflective display region (reflective mode). Since only the illumination light is blocked in the display area (transmission mode), red display cannot be realized, and the user feels black display. In this case, the balance between the colors of the reflection mode and the transmission mode is remarkably lost, but the display is possible.
[0022]
An electronic apparatus according to the present invention includes the electrophoretic display device according to the present invention.
ADVANTAGE OF THE INVENTION According to this invention, the electronic device provided with the display part which has favorable visibility irrespective of use environment is realizable.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The electrophoretic display device of this embodiment is an example of an active matrix electrophoretic display device using a thin film transistor (hereinafter abbreviated as TFT) as a switching element. FIG. 1 is a plan view showing an upper substrate constituting the electrophoretic display device of the present embodiment. FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1, and the electrophoretic display device of the present embodiment. It is a figure for demonstrating the display principle of.
[0024]
As shown in FIG. 2, the electrophoretic display device 1 of the present embodiment includes a lower substrate 2 (first substrate) and an upper substrate 3 (second substrate) made of a light-transmitting base material such as glass. Between a large number of charged particles 4 (first charged particles) of white (first color) charged negatively (first polarity) and black (first charged) of positive (second polarity). A light-transmitting liquid layer 6 in which a large number of charged particles 5 (second charged particles) of the second color are dispersed is sandwiched. For example, charged particles have TiO as their core. ₂ And a coating layer of polyethylene or the like colored in white or black is formed around it. As a dispersion medium for dispersing the charged particles, for example, a mixed liquid of ethylene tetrachloride and isoparaffin is used. Hereinafter, the liquid layer 6 including the charged particles 4 and 5 is referred to as an electronic ink layer.
[0025]
As shown in FIG. 1, the upper substrate 3 has a configuration in which a plurality of data lines 8 and a plurality of scanning lines 9 are arranged in a lattice pattern, and an area surrounded by adjacent data lines 8 and adjacent scanning lines 9 is formed. A single pixel 10 (unit region) constituting a display pattern such as a character or a picture. A first electrode 11 having a substantially rectangular shape is formed in one pixel 10, a rectangular opening 11a is provided in the first electrode 11, and a second electrode is provided in the opening 11a. 12 is formed. 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. 1, and this TFT 15 controls the voltage applied to the first electrode 11. Similarly, a TFT 16 is also formed at the lower left of the pixel 10 in FIG. 1, and this TFT 16 controls the voltage applied to the second electrode 12. With this configuration, the first electrode 11 and the second electrode 12 can be electrically driven independently.
[0026]
A third electrode 13 is formed over the plurality of pixels 10 on the upper surface of the lower substrate 2 and overlaps the first electrode 11 in a planar manner. Therefore, the third electrode 13 is provided with an 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.
[0027]
Among the above components, the data line 8, the scanning line 9, the TFTs 15 and 16 and the like may be formed of a non-transparent metal film, silicon film, or the like, but the first to third electrodes 11 and 12 may be formed. , 13 must be formed of a transparent conductive film such as ITO (Indium Tin Oxide).
[0028]
That is, when the cross-sectional structure is seen, 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 are opposed to each other with the electronic ink layer 6 therebetween. The second electrode 12 on the substrate 3 side is not opposed to 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 side face each other is a reflective display region R, and the second electrode A region where only 12 exists is a transmissive display region T. As shown in FIG. 1, the area of the transmissive display region T in one pixel 10 is sufficiently smaller than the area of the reflective display region R. The dimension of the transmissive display region T (shorter side) is preferably smaller than the gap between the upper and lower substrates 2 and 3 (layer thickness of the electronic ink layer 6). Is set to 50 μm, the width of the transmissive display region T (the lateral dimension of the second electrode 12 in FIG. 1) is preferably about 10 μm. The reason will be described later.
[0029]
Further, a backlight 22 (illuminating means) having a normal light source such as a cold cathode tube that emits white light and an LED is provided on the outer surface side of the lower substrate 2.
[0030]
The display principle of the electrophoretic display device 1 of the present embodiment having the above-described configuration will be described with reference to FIGS. Here, it is assumed that the user views the display from the upper side of the upper substrate 3.
[0031]
First, a predetermined voltage (hereinafter referred to as V1) is applied to the first electrode 11 on the upper substrate 3 side, and a predetermined voltage (hereinafter referred to as V2) is applied to the third electrode 13 on the lower substrate 2 side. And an intermediate potential between V1 and V2 is applied to the second electrode 12 on the upper substrate 3 side. At this time, it is assumed that the direction of the electric field is a direction from the first electrode 11 toward the third electrode 13 from the relationship between V1 and V2. When the voltage is applied to each of the electrodes 11, 12, 13 as described above, the white charged particles 4 are attracted to the first electrode 11 on the upper substrate 3 side as shown in FIG. While the black charged particles 5 are attracted to the third electrode 13 on the side, neither charged particle is attracted to the second electrode 12 on the upper substrate 3 side.
[0032]
Accordingly, since neither charged particle is present in the transmissive display region T, the white light L1 emitted from the backlight 22 is not absorbed or scattered, and the electronic ink layer 6 and the second electrode are used as they are. 12. The light passes through the upper substrate 3 and reaches the eyes of the user. Further, 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 the sunlight or illumination incident from above the upper substrate 3 is illuminated. External light L2 such as light is scattered by a large number of white charged particles 4 on the first electrode 11 and reaches the eyes of the user. By these actions, both the transmissive display area T and the reflective display area R are in the “white display” state in the voltage application state as described above.
[0033]
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, the first electrode 11 has a different voltage (hereinafter referred to as V3 and V3). And the third electrode 13 is fixed at V2. At this time, it is assumed that the direction of the electric field is a direction from the third electrode 13 toward the first electrode 11 due to the relationship between V3 and V2. The same potential V3 as that of the first electrode 11 on the same substrate is applied to the second electrode 12 on the upper substrate 3 side. When the voltage is applied to each of the electrodes 11, 12, 13 as described above, the black charged particles 5 are applied to the first electrode 11 and the second electrode 12 on the upper substrate 3 side as shown in FIG. As a result, the white charged particles 4 are attracted to the third electrode 13 on the lower substrate 2 side.
[0034]
Therefore, in the transmissive display region 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 thus 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 a 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. By these actions, both the transmissive display area T and the reflective display area R are in the “black display” state in the voltage application state as described above.
[0035]
When the display color is switched from the “white display” state shown in FIG. 2A to the “black display” state shown in FIG. 2B, the display color is attracted to the reflective display region R in the “white display” state. It is necessary to diffuse the charged black particles 5 so as to spread into the transmissive display area T (on the second 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 reach the entire surface of the transmissive display region T, and in this case, the contrast is lowered. For this reason, it is desirable that the size of the transmissive display region T is small to some extent.
[0036]
As described above, according to the electrophoretic display device 1 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 constituting the display pattern. Therefore, it can function as a so-called transflective display device. Accordingly, the backlight 22 can be turned on in a dark place and the display can be visually recognized mainly by the transmissive display mode, and the backlight 22 can be turned off in a bright place and the display can be visually recognized by the reflection display mode by external light. Therefore, an electrophoretic display device having good visibility can be realized.
[0037]
[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a cross-sectional view corresponding to FIG. 2 of the first embodiment, and is a view 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 area. Therefore, in FIG. 3, the same components as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0038]
In the case of the first embodiment, the electrode is provided on the upper substrate side in the transmissive display area, whereas in the case of the present embodiment, the electrode is provided on the lower substrate side in the transmissive display area. That is, as shown in FIGS. 3A and 3B, the electrophoretic display device 30 according to the present embodiment has the first electrode 31 in the reflective display region R on the lower substrate 2 side and the transmissive display region T in the first display. Two electrodes 32 are provided, and a third electrode 33 is provided in the reflective display region T on the upper substrate 3 side. Therefore, in the present embodiment, the pattern shown in FIG. 1 may be considered as the lower substrate 2, contrary to the first embodiment. Other configurations are the same as those in the first embodiment.
[0039]
The display principle of the electrophoretic display device 30 of the present embodiment having the above configuration will be described with reference to FIGS. However, as is clear from the figure, the movement and action of each charged particle in the reflective display area T are not different from those in the first embodiment shown in FIGS. Only explained.
[0040]
First, V1 is applied to the first electrode 31 on the lower substrate 2 side, V2 is applied to the third electrode 33 on the upper substrate 3 side, and V1 is applied to the second electrode 12 on the lower substrate 2 side. When an intermediate potential of V2 and V2 is applied, as shown in FIG. 3A, neither charged particle is attracted to the second electrode 32 on the lower substrate 2 side. Accordingly, in the transmissive display region T, the white light L1 from the backlight 22 is not absorbed or scattered, but sequentially passes through the second electrode 32, the electronic ink layer 6, and the upper substrate 3 to reach the eyes of the user. To do. Thus, in the voltage application state as described above, both the transmissive display region T and the reflective display region R are in the “white display” state.
[0041]
Next, V3 is applied to the first electrode 31 on the lower substrate 2 side, the potential of the third electrode 33 on the upper substrate 3 side is fixed at V2, and the second electrode on the lower substrate 2 side is fixed. The same V3 as that of the first electrode 31 is applied to the electrode 32. When the voltages are applied to the electrodes 31, 32, 33 in this way, the white charged particles 4 are applied to the second electrode 32 on the lower substrate 2 side together with the first electrode 31 as shown in FIG. Will be attracted. Therefore, in the transmissive display region T, the white light L1 emitted from the backlight 22 is reflected (scattered) by the many 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 user's eyes. Thus, in the voltage application state as described above, both the transmissive display region T and the reflective display region R are in the “black display” state.
[0042]
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 in one pixel 10 constituting the display pattern. Since it can function as a transflective display device, it is possible to realize an electrophoretic display device having good visibility regardless of the brightness of the use environment, and the same effect as that of the first embodiment. Obtainable.
[0043]
[Electronics]
Next, a specific example of an electronic apparatus including the electrophoretic display device according to the above 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 denotes a mobile phone main body, and reference numeral 1001 denotes a display unit using the electrophoretic display device.
[0044]
FIG. 5 is a perspective view showing an example of a wristwatch type electronic apparatus. In FIG. 5, reference numeral 1100 indicates a watch body, and reference numeral 1101 indicates a display unit using the electrophoretic display device.
[0045]
FIG. 6 is a perspective view showing an example of a portable information processing apparatus such as a word processor or a personal computer. In FIG. 6, reference numeral 1200 denotes an information processing apparatus, reference numeral 1202 denotes an input unit such as a keyboard, reference numeral 1204 denotes an information processing apparatus body, and reference numeral 1206 denotes a display unit using the electrophoretic display device.
[0046]
4 to 6 includes a display unit using the electrophoretic display device of the above embodiment, so that an electronic device having good visibility can be realized regardless of the use environment. it can.
[0047]
The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, an example in which an electrode is provided on only one of the upper substrate and the lower substrate in the transmissive display region has been shown. However, even if electrodes are provided on both substrates, When the first electrode is set to an intermediate potential, white display is performed, and when both electrodes are set to the same potential as the electrodes in the reflective display region on each substrate, black display is performed. In the present invention, when white display is realized in the transmissive display region, it is described that none of the charged particles are present. However, a slight amount of charged particles is present if a slight reduction in contrast is allowed. Also good. Alternatively, light may be scattered by the presence of a few charged particles.
[0048]
Furthermore, in the above embodiment, an example in which the present invention is applied to an active matrix type device using TFTs as switching elements has been shown. However, an active matrix type device using thin film diodes (TFDs) as switching elements, Alternatively, the present invention can be applied to a passive matrix type device. In addition, as described in the section [Means for Solving the Problems], other combinations are possible for the color of the charged particles and the color of the illumination light of the backlight described in the above embodiment. In addition, specific descriptions of materials, dimensions, shapes, and the like of each component can be appropriately changed.
[0049]
【The invention's effect】
As described above in detail, according to the present invention, an electrophoretic display device that can function as a transflective display device and has good visibility regardless of the brightness of the use environment is realized. Therefore, for example, it is suitable for application to portable electronic devices and the like.
[Brief description of the drawings]
FIG. 1 is a plan view showing an upper substrate constituting an electrophoretic display device according to a first embodiment of the invention.
2 is a cross-sectional view taken along the line AA ′ in FIG. 1, for explaining the display principle of the electrophoretic display device of the present embodiment. FIG.
FIG. 3 is a cross-sectional view illustrating an electrophoretic display device according to a second embodiment of the present invention, and 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 apparatus according to the invention.
FIG. 5 is a perspective view showing another example of an electronic apparatus according to the invention.
FIG. 6 is a perspective view showing still another example of the electronic apparatus according to the 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 1st electrode
12, 32 Second electrode
13, 33 third electrode
22 Backlight (lighting means)

Claims (6)

A plurality of first charged particles of the first color charged to the first polarity between the first substrate and the second substrate both having translucency, and the polarity opposite to the first polarity liquid having a second translucent containing a plurality of second charged particles a second color different from the first color charged to polarity while being sandwiched, of the first substrate Illumination means are provided on the outer surface side,
It has a transmissive display area and a reflective display area in one unit area constituting the display pattern,
In the transmissive display area, the first charged particles are excluded from the transmissive display area, so that the illumination light from the illuminating means is transmitted from the first substrate side to the second substrate side. While the color of the light is visible , at least one of the first charged particles and the second charged particles is present in the transmissive display region, so that the illumination light is absorbed or reflected. Transmission of the illumination light from the first substrate side to the second substrate side is blocked,
In the reflective display region, wherein by the first charged particles are attracted to the second substrate, while the first color of the first charged particles Ru is visible, the second charged particles Is adsorbed on the second substrate, whereby the second color of the second charged particles can be visually recognized. In the reflective display area, an electric field in the reverse direction is applied to be switchable between the first substrate and the second substrate. In the transmissive display area, the first substrate, according to claim 1, wherein an intermediate potential between the voltage and the voltage of the second substrate of the first substrate to one of said second substrate is configured to be applied Electrophoretic display device. In the reflective display region, an electrode made of a transparent conductive film is provided on each of the first substrate and the second substrate, and either the first substrate or the second substrate is provided in the transmissive display region. The electrophoretic display device according to claim 2 , wherein an electrode made of a transparent conductive film is provided on one side. A plurality of first charged particles of the first color charged to the first polarity between the first substrate and the second substrate both having translucency, and the polarity opposite to the first polarity A translucent liquid containing a plurality of second charged particles having a second color different from the first color charged to the second polarity is sandwiched between the first substrate and the first substrate. Illumination means are provided on the outer surface side,
One unit area constituting the display pattern has a transmissive display area and a reflective display area. In the transmissive display area, the illumination means emits light depending on the presence or absence of the first charged particles and the second charged particles. Switching between transmission and blocking of illumination light, and in the reflective display area, the first color is visually recognized depending on which of the first charged particles and the second charged particles is adsorbed to the second substrate. An electrophoretic display device that switches between making the second color visible and making the second color visible. The electrophoretic display device according to any one of claims 1 to 4 , wherein the first color is white and the second color is black. An electronic apparatus comprising the electrophoretic display device according to any one of claims 1 to 5 .

Images