JP2002311461A - Display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-state display element to transfer fine particles in parallel in the absence of medium. SOLUTION: The display element has transparent non-pixel electrodes 21 , 22 , 23 formed on the upper surface of a substrate 1 having insulation characteristics and pixel electrodes 24 , 25 formed among the non-pixel electrodes 21 , 22 , 23 . Light shielding parts 61 , 62 , 63 colored with the same width as that of the electrodes are arranged on the lower side of the non-pixel electrodes 21 , 22 , 23 . At least one kind of colored fine particles 4 are arranged on the upper surface of the non-pixel electrode 21 the pixel electrode 25 and the fine particles 4 are transferred approximately in parallel with the substrate 1 in the absence of medium and in the arranged direction of the electrodes 21 to 25 as shown by an arrow Y by an electric field to be impressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle-moving display device which performs display by moving particles between electrodes in a medium-free state.

[0002]

2. Description of the Related Art Conventionally, various display elements have been proposed, developed and put to practical use as flat panel displays. Also, with the development of information devices and the widespread use of mobile phones and mobile devices, research and development of reflective display elements as low power consumption displays are progressing.

For example, a liquid crystal display device uses a display element that modulates light from a light source by applying an electric field to an element composed of a combination of a liquid crystal material and a deflecting plate and using the liquid crystal as an optical shutter. It has become widespread as a flat display in a wide range of fields such as portable terminals and monitors for television receivers. However, a liquid crystal display device requires a polarizing plate in principle, only 50% or less of the light from the light source is used for display, and a reflection type liquid crystal display device without a backlight has insufficient brightness and visibility. It has disadvantages such as chipping.

On the other hand, a display device utilizing the electrophoretic phenomenon of fine particles between electrodes is disclosed in US Pat. No. 3,612,758.
And Japanese Patent Application Laid-Open No. 49-24695. For example, in the display device described in US Pat. No. 3,612,758, as shown in FIG. 39A, the fine particles 4 charged up by applying an electric field to the electrode 2 are sandwiched between the upper and lower substrates 1. The display device is moved in the insulating liquid layer 3 to form a display device. When the fine particles 4 are located on the upper side, that is, on the observer side, the color of the fine particles is displayed. indicate. Thus, different colors can be switched and displayed.

Further, as shown in FIG. 40, a display device described in Japanese Patent Application Laid-Open No. 49-24695 discloses a fine particle 4 charged by applying an electric field to an electrode 2.
Is moved laterally, that is, in a direction parallel to the substrate 1 in the insulating liquid layer 3 sandwiched between the upper and lower substrates 1 to perform display. Further, as another conventional electrophoretic display device, U.S. Pat. No. 4,126,854 discloses an electric field applying fine particles 4 arranged between charged electrodes 2 and having different colors, as shown in FIG. A configuration in which the display color is switched by rotating the display color is disclosed.

In the above-described electrophoretic display device, the color is switched by moving the colored fine particles to a directly visible position or an invisible position by electrophoresis. Therefore, it is necessary to use a polarizing plate like a liquid crystal display device. Therefore, there is an advantage that a bright display device can be realized.

[0007] A powder moving device is also known. For example, a powder moving device disclosed in Japanese Patent Application Laid-Open No. 7-267363 discloses a powder moving device on an insulating substrate 1 as shown in FIG. The electrodes 5 are arranged in parallel, and an alternating voltage is applied to the electrodes 5. The powder is moved by electrostatic force generated by the application of the alternating voltage.

[0008]

However, the conventional electrophoretic display device and the powder moving device have the following problems. U.S. Pat. No. 3,612,758,
JP-A-49-24695 and U.S. Pat.
The display device described in Japanese Patent Application No. 854 has a configuration in which fine particles 4 basically move in the insulating liquid layer 3. As described above, since the insulating liquid layer 3 is always sandwiched between the pair of substrates 1, the insulating liquid layer 3 may leak or may erode the material of the electrode 2 or the like depending on the material of the insulating liquid layer 3. This can cause problems and can significantly reduce the reliability of the display device.

Furthermore, the insulating liquid layer 3 may expand and contract due to environmental changes such as temperature and atmospheric pressure, and may cause air bubbles in the device. However, if air bubbles are generated in the display device, the display quality will be degraded. In addition to the problem of lowering, the electric field applied to the insulating liquid layer 3 also becomes non-uniform depending on the location, so that there is a possibility that the switching mechanism for switching colors cannot be controlled, and it functions as a display device. You may not get it.

As described above, the fluid insulating liquid layer 3
The use of as a component of the display device, display performance,
Neither of the switching performances is desirable, but a display device using a solid constituent material is desirable.

Further, there is a problem in that the fine particle migration type display device using such an insulating liquid layer 3 has poor contrast. This is because the insulating liquid layer 3 is filled between the fine particles 4 even when the fine particles 4 are on the side of the upper substrate to display the color of the fine particles 4 as shown in FIG. Therefore, the color of the insulating liquid layer 3 itself is
Is mixed with the color of
It is impossible to completely form the display state of only the fine particles 4.

As described above, in the display using the combination of the insulating liquid layer 3 and the fine particles 4, the display device not using the insulating liquid layer 3 has a higher contrast in view of the fact that the contrast cannot be increased. desirable.

On the other hand, a powder transport device can only move powder or fine particles without using a flowing liquid, and no device structure or system using the device as a display device has been proposed. .

The present invention has been proposed in order to solve the above-mentioned conventional problems, and the reliability of an all-solid-state type is improved by the electrostatic movement of fine particles in a medium-free state and a special device structure. It is an object to provide a high and bright display element.

[0015]

Means for Solving the Problems In order to achieve the above object, the invention of claim 1 includes a first substrate having an insulating property, a first electrode formed on the substrate, First
At least one type of fine particles arranged on the electrode of
Wherein the fine particles are moved in parallel with the first substrate without a medium by a voltage applied to the electrode.

According to another aspect of the present invention, there is provided a first substrate having an insulating property, a first electrode formed on the substrate, and a first electrode formed on the first substrate. At least one kind of fine particles disposed thereon, a second substrate disposed at a predetermined distance from the first substrate,
And a second electrode formed on the second substrate.
A display element, wherein the fine particles are moved with respect to the first substrate and the second substrate without a medium by a voltage applied to the first electrode and the second electrode. provide.

The invention according to claim 3 is characterized in that the first electrode and the second electrode have the same shape. The invention according to claim 4 is characterized in that a structure for partitioning pixels is formed between the first substrate and the second substrate.

The invention according to claim 5 is characterized in that the structure is charged. The invention according to claim 6 is characterized in that the first
A sealing member for sealing a peripheral portion between the first substrate and the second substrate to prevent moisture from permeating.

The invention according to claim 7 is characterized in that an insulating film is formed on the first electrode. The invention according to claim 8 is characterized in that a charge transport film is formed on the first electrode.

According to a ninth aspect of the present invention, a protective film is formed on the first electrode, and the protective film has a resistance at a position where the distance between the surface of the protective film and the first electrode is the shortest. The voltage is higher than the voltage applied between the adjacent first electrodes.

According to a tenth aspect of the present invention, the first substrate includes:
The first electrodes having different sizes are formed. An eleventh aspect of the present invention is characterized in that the first electrode has a three-pole structure and is driven independently in three phases.

According to a twelfth aspect of the present invention, the first electrode in one pixel includes a non-pixel electrode and a pixel electrode, and the non-pixel electrode and the pixel electrode are alternately arranged in a plurality of the pixels. And a distance between the non-pixel electrode and the pixel electrode is smaller than a distance between the pixel electrode in one pixel and the non-pixel electrode in a pixel adjacent to the pixel. And

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments relating to a display device according to the present invention will be described below with reference to the drawings. In the drawings, the same reference numeral and reference numeral indicate the same element.

FIGS. 1A and 1B are views schematically showing a first embodiment of a display element according to the present invention.
In the figure, the display element in the first embodiment is
A substrate 1 having an insulating property, a plurality of narrow transparent electrodes 2 ₁ , 2 ₂ , 2 ₃ formed on the upper surface of the substrate, and a space between these narrow electrodes 2 ₁ , 2 ₂ , 2 ₃ wide electrode 2 ₄ formed,
2 ₅ . Hereinafter, the wide electrodes 2 ₄ and ₂₅ constitute a pixel, and will be referred to as pixel electrodes. On the other hand, the narrow electrodes 2 ₁ , 2 ₂ and 2 ₃ are not elements constituting a pixel, and therefore, will be referred to as non-pixel electrodes. I will call it. Under the non-pixel electrodes 2 ₁ , 2 ₂ , 2 ₃ , light-shielding sections 6 ₁ , colored with the same width as the electrodes,
6 _2, 6 ₃ are arranged. On the upper surface of the non-pixel electrodes 2 ₁ and the pixel electrode 2 _5, fine particles 4 which are colored are arranged by an electric field particles 4 applied, as indicated by an arrow Y, into the substrate 1 under no medium substantially parallel to and electrodes 2 ₁ to for
It is moved in the array direction of ₂₅ .

[0025] In the above configuration, it is assumed that an electric field is applied to the plurality of electrodes 2 ₁ to 2 ₅ formed on the substrate 1. At this time, the non-pixel electrodes 2 ₁ and particulates 4 disposed on the pixel electrode 2 ₅ electrostatic charge is imparted. Therefore, the fine particles 4 of the electrostatic charge is applied, Coulomb force acts between the charges generated in the electrodes 2 _4, 2 ₃ adjacent to the electrodes 2 _1, 2 ₅ fine particles are arranged, which particles 4 by the It translates on the substrate 1. Thus, the viewer electrodes 2 ₁ to
Since the appearance of ₂₅ , the light shielding layer 6 and the fine particles 4 changes,
By controlling the method of applying an electric field to the electrodes, a solid-state display element can be manufactured.

By the display method based on such parallel movement of the fine particles 4, the display element shown in FIG. 1 has a state in which the fine particles 4 are provided on the narrow electrode on the light shielding layer 6 and a state in which the fine particles are provided on the wide electrode. By switching between
Changes the display state of the surface of. Alternatively, as shown in FIG. 2, the display state of the substrate surface can be changed by switching between a state (a) in which the fine particles 4 are dispersed and a state (b) in which the fine particles 4 are aggregated. However, the display method in the present invention is not limited to these, and any method may be used as long as the fine particles 4 are moved with respect to the substrate 1 in a medium-free state to change the display state on the surface of the substrate. .

Assuming that the substrate 1 is light transmissive, as shown in FIG. 3A, a transmissive display in which light from a light source is irradiated from the lower surface of the substrate 1 (ie, the surface on which no electrodes are formed). An element can be formed.
The reflection type display element which reflects the light source light from the upper surface of the substrate 1 by the reflection plate 7 can be configured as shown in FIG.

Fine particles 4 used in the display element shown in FIG.
Covers electrodes 2 _4, 2 ₅ of one rests magnitude relative to one pixel constituted by each, i.e., it may be in a size to form one pixel, the one electrode in the plurality of particulates You may run out.

The display device having the structure as shown in FIG.
By making the fine particles 4 and the light shielding layer 6 black, it is possible to switch between white and black without using a polarizing plate. Further, the display element of FIG. 1 does not use the insulating liquid layer required by the conventional electrophoretic display device,
Since the element is a medium-less element, it is possible to directly observe the color of the fine particles 4, and it is possible to create a bright display element without deteriorating the contrast. Further, since the switching element uses electrostatic force, a display element with low power consumption without flowing current can be provided. As described above, by moving the fine particles 4 without using a medium, it is possible to provide a display element that is bright, has high contrast, and consumes low power.

FIG. 4 schematically shows a display element according to a second embodiment of the present invention. The display element according to the second embodiment includes a substrate 1, a plurality of electrodes 2 of the same shape formed on the upper surface of the substrate and forming pixels, and an insulating material formed to cover the plurality of electrodes. An insulating film 8 made of a dielectric material. The fine particles 4 are provided on the electrode 2 via the insulating film 8.

As in the first embodiment, an electric field is applied to the electrode 2, and an electrostatic charge is applied to the fine particles 4 arranged on the electrode 2. Therefore, a Coulomb force acts between the fine particles 4 to which the electrostatic charge is applied and the electric charges generated on the electrode 2 adjacent to the electrode 2 on which the fine particles are arranged. Translate in the direction. The principle of this parallel movement will be described with reference to FIG. FIG.
As shown in the (a), fine particles 4 is installed at one of the electrodes 2 ₆ via the insulating film 8, to the electrode 2 ₆ positive potential and the other electrode 2 ₇ is placed to the negative potential A negative electrostatic charge is added to the fine particles 4 through the insulating film 8. Then, as shown in FIG. 5 (b), changing the potential of the electrode 2 ₆ negative, changing the potential of the adjacent electrodes 2 ₇ positively, fine particles 4 which is added a negative static charge
Is repelled from the electrode ₂₆ by Coulomb force, and the adjacent electrode 2 ₇
It comes to attract. As a result, fine particles 4 is moved parallel to the adjacent electrode 2 _7.

The speed of the parallel movement of the fine particles 4 and the electric field strength required for the parallel movement vary depending on the dielectric constant and thickness of the insulating film 8, the friction coefficient of the surface of the insulating film 8, the electrode interval, and the like.
It also depends on the type of fine particles. However, most fine particles can be used as the fine particles 4 irrespective of the conductivity, chargeability, and shape of the fine particles, and it is not necessary to charge the fine particles themselves from the beginning. Of course, when the fine particles themselves are charged, the fine particles can be moved by the first electric field application. By determining the optimum combination of the fine particles 4 and the insulating film 8 in consideration of such requirements, the electric field conditions for moving the fine particles 4 can be set.

As described above, in the second embodiment shown in FIG. 4, the fine particles 4 can be arbitrarily combined by applying an electric field for charging the fine particles 4 and an electric field for moving the fine particles 4. It is possible to move. By utilizing the principle of moving the fine particles, the transmitting state and the reflecting state of the surface of the substrate 1 are changed by moving the fine particles 4 between the outside of the pixel and the inside of the pixel and controlling the dispersion state of the fine particles 4. be able to.

In the second embodiment of the present invention, an image force (image for
Since ce) works, the display can be kept even after the electric field is cut off, and a display element having a so-called memory property can be obtained. In addition, by providing the insulating film 8, leakage between adjacent electrodes can be prevented, and arcing between the electrodes due to aggregation of charged fine particles can be prevented. For this reason,
By providing the insulating film 8, a display element having higher reliability can be manufactured.

As described above, according to the second embodiment,
The present invention provides a display element that realizes fine particle movement by a charging and moving process irrespective of the type of fine particles by providing an insulating film on an electrode, and further, a display element having excellent memory and excellent reliability. Can be provided.

FIG. 6 is a diagram schematically showing a third embodiment of the display element according to the present invention. The third embodiment shown in FIG. 6 is different from the third embodiment in that a charge transport film 9 is formed instead of the insulating film 8 in the second embodiment shown in FIG. With such a configuration, in the third embodiment, an electric field is applied to the fine particles 4 via the charge transport film 9 formed so as to cover the top of the electrode 2, and charges are injected.

In the device shown in FIG.
The principle of the parallel movement on is described with reference to FIG. Here, a case where a hole transport film is used as the charge transport film 9 will be described. However, when an electron transport film is used, the polarity is only reversed, and the same behavior is exhibited in principle. FIG.
As shown in (a) of FIG.
There installed electrodes 2 ₆ positive potential, when the electrodes 2 ₇ adjacent to the negative potential thereto, particulates on the electrode 2 ₆ of the positive potential is obtained a positive electrostatic charge through the charge transport layer 9. When a certain amount of positive electrostatic charge is accumulated in the fine particles 4 in this way, the fine particles 4 and the electrode 26 below the fine particles 4
And between the positive etc. acts Coulomb force repulsion press, whereas, between the fine particles 4 and the electrode 2 ₇ adjacent the Coulomb force attracting acts. As a result, fine particles 4 is moved parallel to the electrode 2 ₇ adjacent.

The speed of the parallel movement of the fine particles 4 and the electric field strength required for the parallel movement include the charge transport ability and the thickness of the charge transport film 9, the friction coefficient of the surface of the charge transport film 9, the electrode spacing, When the charge transporting film 9 includes a binder resin, the ratio differs depending on the mixing ratio of the charge transporting material and the binder resin. Most fine particles can be used as the fine particles 4, and it is not necessary to charge the fine particles 4 from the beginning. However, using a fine particle having conductivity or a fine particle having an ability to accept electric charge results in an excellent display element. Considering these requirements, the fine particles 4
By determining the optimal combination of the charge transport film 9 and the charge transport film 9, it is possible to set the electric field condition for moving the fine particles.

As described above, in the third embodiment of the present invention, the fine particles are moved outside the pixel and inside the pixel by using the fine particle movement principle of applying the electric field to the electrode 2 to charge and move the fine particles 4. The state of transmission or reflection on the surface of the substrate 1 can be changed by moving the substrate 1 or controlling the state of dispersion of the fine particles. Further, in the third embodiment, as in the second embodiment, even after the electric field is cut off,
Since the charged fine particles 4 exert a mirror image force on the substrate, the display can be stored, and a display element having a so-called memory property can be provided. As described above, in the third embodiment, by providing the charge transport film 9 on the electrode 2, the process of charging and moving the fine particles 4 is performed by a single electric field application regardless of the type of the fine particles. A display element, and further, a display element having a memory property and excellent reliability can be provided.

FIG. 8 schematically shows a fourth embodiment of the display element according to the present invention. The fourth embodiment is different from the first embodiment described above in that the width of the non-pixel electrode 10 is smaller than that of the light shielding layer 6.

In the display element of the present invention utilizing the parallel movement of the fine particles, the fine particles move on the electrode, and the fine particles exist on the electrode or in the vicinity of the electrode during display.
Therefore, for use as a display element, the contrast can be increased when the difference between when the fine particles 4 are present on the pixel electrode 11 and when the fine particles 4 are not present or when the difference in the display state due to the aggregation and dispersion of the fine particles 4 is large. So desirable.

For example, as shown in FIG.
When the fine particles (not shown) move between 0 and the pixel electrode 11, the fine particles exist in the non-pixel portion including the non-pixel electrode 10 and the light shielding layer 6, and the fine particles exist on the pixel electrode 11. It is preferable that the display state has a large difference in the display state. Therefore, when there is a large difference in the size between the non-pixel electrode 10 and the pixel electrode 11, the difference in the display state can be made large. For example, when the black fine particles are moved, and when the black fine particles are present in the non-pixel electrode 10, the state of the color of the lower portion of the pixel electrode 11 is displayed. Next, when the black fine particles move to the pixel electrode 11, the pixel electrode 11 also has a black state due to the presence of the black fine particles, and as a result, the whole substrate is in a black state. Therefore, the contrast as a display element is determined by the difference between the white display and the black display,
It is desirable that the non-pixel electrode 10 is small. Speaking of the two-state display of black and white, by making the non-pixel electrode 10 smaller than the pixel electrode 11, a brighter display element can be created as compared to the case where the liquid crystal display element reduces transmission light by half by the deflection plate. it can. The same can be said for the change in the display state due to the aggregation and dispersion of the fine particles.

As described above, the non-pixel electrode 10 and the pixel electrode 1
By providing a difference from the size of 1, the performance as a display element can be improved. The shape of these electrodes is arbitrary, and in addition to a square as shown in FIG. 8, both electrodes may be circular as shown in FIG. Further, as shown in FIG. 10, by changing the size of the pixel electrode 11 stepwise, the difference in the display state can be finely changed, so that gradation display is possible.

As described above, according to the fourth embodiment of the present invention, it is possible to provide a display element in which the display performance is improved by changing the sizes of the pixel electrode and the non-pixel electrode. .

In the first to fourth embodiments described above, an electrode is formed on a single substrate, fine particles are placed on the electrode, and the fine particles are moved in parallel to function as a display element. It is to let. However, in this case, the fine particles are exposed to the outside air, which may cause a problem that the fine particles are scattered due to an external environment or contact, or the movement of the fine particles is hindered by moisture or the like. Therefore, by providing a counter substrate at a fixed interval with respect to one substrate, disposing fine particles between a pair of substrates, and sealing a peripheral portion of the substrate with a sealing member, higher reliability is achieved. A display element can be created. This will be described later.

When particles charged by applying an electric field to the electrode move from electrode to electrode in parallel with the substrate,
Since the particles are charged to the same polarity as the lower electrode, the particles generate a repulsive force from the lower electrode. Therefore, FIG.
As shown in FIG. 1, an upward force 12 acts on the fine particles 4 from the lower electrode ₂₆ via the insulating film 8. Simultaneously, the fine particles 4 acts attraction 13 from adjacent electrodes 2 _7. Therefore, fine particles 4 during movement, emerge shake off the adhesion between the particles and the substrate, so that moving a parabola with respect to the adjacent electrode 2 _7. Further, fine particles 4, the particle size is by cloth or charged state not exhibit a constant behavior, may also be present do not move toward the adjacent electrode 2 _7. If a counter substrate is provided, the adjacent electrode 2 ₇
The fine particles that have not moved to the side adhere to the opposing substrate and cannot be separated from the opposing substrate by a mirror image with the opposing substrate. This makes it impossible to indicate a change in the display state due to the movement of the fine particles.

In order to solve this problem, in the fifth embodiment of the display element according to the present invention, as shown in FIG. 12, a counter substrate 14 is formed on a substrate 1 on which electrodes 2 having the same shape are formed. provided the fine particles 4 disposed between the substrates, also to form the electrode 2 ₈ on the counter substrate 14. The electrodes 2 ₈ of the counter substrate 14, an electric field is applied to the same polarity as the charged particles. Thus, as shown in FIG. 12, given the direction of the electrostatic force 15 of the substrate 1 from the electrodes 2 ₈ against fine particles 4 to suppress the upward flight of particles 4, is possible to realize a more mobile linear parallel it can. Further, it is possible to prevent the fine particles 4 from adhering to the opposing substrate 14, thereby providing a display element having excellent display characteristics.

When the adhesion between the fine particles 4 and the insulating film 8 is strong, the fine particles 4 may not be able to separate from the insulating film 8 due to the repulsive force from the electrode ₂₆ . In this case, by applying an electric field to the electrodes 2 ₈ to pulling the fine particles 4 of charged, it is possible to translate by detached fine particles 4 from the adhesive force between the insulation film 8.

[0049] Thus, the fifth embodiment of the present invention, by applying an electric field to the electrodes 2 ₈ to fine particles 4 is provided on the counter electrode 14, and realizes the parallel movement of the particles 4,
A display element having excellent display characteristics can be provided.

The fifth embodiment described above has a configuration in which electrodes are formed on a pair of substrates 1 and 14, and the fine particles 4 are moved by the electrodes formed on these substrates. In the parallel movement of the fine particles 4, basically, the fine particles move one by one. In addition, the fine particles 4 can be moved by superposing a plurality of layers. In particular, when the electrodes having different sizes are provided as shown in FIGS. Since the particles are dispersed as compared with those on the electrode 10, the overlap between the fine particles may be reduced, or the particles may become only a single layer. Furthermore,
The moving particles are charged to the same potential, so basically
A repulsive force acts between the fine particles, and voids are often generated between the fine particles. In such a state, as shown in FIG. 13A, the pixel electrode 11 cannot be filled with the fine particles, and a display state in which the color of the back surface and the color of the fine particles are mixed is obtained. Even if the fine particles are completely packed on a flat surface, as shown in FIG. 13B, a gap is formed between the fine particles depending on the shape and size of the fine particles, and the surface of the pixel electrode is covered with the fine particles. Because it cannot be completely covered, the difference in the display state due to the movement of the fine particles is reduced,
The contrast cannot be increased.

Therefore, in the sixth embodiment of the display element according to the present invention, the electrodes 2 having the same shape are formed on both the pair of substrates 1 and 14. That is, in the sixth embodiment, as shown in FIG. 14, the electrodes 2 are provided on the opposing surfaces of the pair of upper and lower substrates 1 and 14, respectively.
The charge transport film 9 is provided so as to cover the electrodes 2, and the fine particles 4 are arranged between the opposing charge transport films 9. In this way, the fine particles 4 are moved by the electrodes 2 provided on the upper and lower substrates 1 and 14, so that the electrode 2 is covered by at least two layers of the fine particles 4, and as a result, the fine particles covering the electrode 2 The amount increases. If the area where the fine particles 4 cover the electrode 2 in each substrate is 50% or more,
Alternatively, if the sum of the areas covered by the fine particles 4 on both the substrates 1 and 14 is 100% or more, each pixel can be completely covered, so that the contrast can be improved.

Since the sixth embodiment of the present invention has such a configuration, even if the fine particles 4 draw a parabola or fly toward the opposite substrate as shown in FIG. Since the behavior of the fine particles 4 can be controlled by the substrates 1 and 14, flying of the fine particles does not matter. Furthermore, the electrodes 2 formed on the upper and lower substrates 1 and 14 are formed in parallel, and the electrodes 2 on the opposing substrates 1 and 14 are set to the same potential, thereby moving the fine particles 4 toward the opposite substrate. Since a force can be generated, the flying of the fine particles 4 can be suppressed.

The electrodes 2 formed on the pair of substrates 1 and 14 may be parallel to each other as shown in FIG.
As shown in FIG. In the case of the electrode arrangement shown in FIG. 15, by controlling the electric field applied to the electrodes, the movement of the fine particles 4 can be more finely controlled, so that a desired gradation display can be performed. . The shape of each electrode is not limited to those shown in FIGS. 14 and 15, and may be circular,
Each substrate may be different.

As can be understood from the above description, the sixth embodiment of the present invention provides a pair of upper and lower substrates with electrodes of the same shape, and controls the application of an electric field to these electrodes. Since the fine particles are moved between the upper and lower substrates, a display element having excellent display characteristics can be provided.

FIG. 16 is a diagram schematically showing a display element according to a seventh embodiment of the present invention. In FIG.
A rib structure 16 for partitioning individual pixels is formed between a pair of upper and lower substrates 1 and 14, and a non-pixel electrode 10 and a pixel electrode 11 are formed in each partition. The non-pixel electrode 10 is provided on the light shielding unit 6. Thereby, the moving region of the fine particles 4 is defined.

It is desirable that the fine particles 4 always move at the same position repeatedly for the in-plane uniformity in the substrate.
The position of the fine particles 4 is changed by applying an electric field to the electrode 2,
If it is not possible to return to the original position, as a result, the particles will be shifted in the plane, causing display unevenness. Therefore, as shown in FIG. 16, by forming a rib structure 16 for partitioning a pixel for each reciprocating unit of the fine particles 4, the fine particles 4 are formed.
Is defined, and the in-plane variation of the distribution of the fine particles due to the movement of the fine particles 4 can be eliminated. The shape of the rib structure 16 is arbitrary, and may be a stripe shape as shown in FIG. 17A or a shape surrounding a pixel as shown in FIG. 17B.

Further, the rib structure 16 includes the upper and lower substrates 1,
14 can also function as a spacer to keep the distance between them constant. By keeping the distance between the upper and lower substrates 1 and 14 constant, a reliable display element can be produced without the substrates 4 coming into contact with each other and hindering the movement of the fine particles 4. Thus, the rib structure 16
Is formed, it is possible to provide a highly reliable display element without display unevenness.

As shown in FIG. 18, the rib structure 16
Charge may be given. According to this configuration, the rib structure 16 serves as at least one stop point in the movement of the fine particles. For example, the fine particles 4 in the fourth embodiment shown in FIG. 8 move between the electrodes and stop on the electrodes. On the other hand, in the display element shown in FIG. 18, the rib structure 16 itself is the stop position of the fine particles. When the fine particles 4 are originally chargeable, as shown in FIG. 18, the state in which the fine particles 4 adhere to the rib structure 16 itself by the electrostatic force of the rib structure 16 and the electric field applied to the pixel electrode 11 are reduced. Switching between the state in which the fine particles 4 adhere to the pixel electrode 11 by the electrostatic force due to the application can be performed. Further, as shown in FIG. 19, the fine particles 4 are attached to the rib structure 16 itself by forming the rib structure 16 on the non-pixel electrode 10 and charging the rib structure 16 by an electric field formed by the electrode. It is also possible to switch between a state and a state in which the fine particles 4 adhere to the pixel electrode 11 by the electrostatic force generated by the application of the electric field.

As described above, by setting the rib structure 16 at the stop position in the movement of the fine particles 4, the non-pixel portion can be reduced. In order to increase the contrast difference as in the above-described fourth embodiment, it is better that the size difference between the non-pixel electrode and the pixel electrode is large.
There is a limit to moving the fine particles 4 covering 1 to only the non-pixel electrode 10. Therefore, by adopting a configuration in which the fine particles 4 can also be attached to the surface of the rib structure 16, the area to which the fine particles 4 can be attached is enlarged so that the fine particles 4 can be attached three-dimensionally. Can be further reduced.

The rib structure 16 for enlarging the area to which the fine particles 4 can adhere does not necessarily have to have the function of maintaining the distance between the pair of substrates 1 and 14, and therefore, as shown in FIG. There may be a protruding shape that increases the area to which the fine particles 4 are attached, such as to have a height up to the middle between the substrates 1 and 14. Of course, a rib structure having a function of maintaining the interval between the pair of substrates (FIGS. 18 and 19) and a rib structure having a function of increasing the surface area of the non-pixel electrode (FIG. 20)
May be appropriately combined and arranged. in this way,
By applying electric charges to the rib structure 16, a display element with good contrast can be provided.

As described above, various embodiments of the display element according to the present invention have been described. Hereinafter, modified examples common to these embodiments will be described. First, in the case of a display element using a pair of upper and lower substrates 1 and 14, the peripheral portions of the pair of substrates can be sealed with a sealing member to prevent moisture from penetrating inside. According to this configuration, the pair of substrates are sealed, and the sealing member does not allow moisture outside the substrate to pass through the inside of the substrate. As mentioned above,
The fine particles move by an electrostatic force generated by an electric field applied to the electrode. In such an electrostatic drive, the drive conditions change due to moisture such as moisture, so that not only stable display cannot be performed but also drive may not be possible in a humid state. Therefore, it is necessary to always maintain a constant humidity condition in the space between the two substrates.

It is desirable that the sealing member for sealing the upper and lower substrates 1 and 14 be made of a material that does not absorb moisture. Thus, it is possible to prevent the moisture of the outside air from entering the space between the substrates, and it is possible to perform stable driving even when the external environment changes. The sealing member may be of any type that achieves the above object and can seal the peripheral portions of the upper and lower substrates. In addition, any number of sealing members may be stacked so as not to transmit moisture. As described above, by using a sealing material that is impermeable to moisture, an element that performs stable display without being affected by an external environment can be provided.

When a display element in which the periphery of the pair of substrates 1 and 14 is sealed with a sealing member, the upper and lower substrates 1 and 1
4 may be filled with an inert gas. By filling the inert gas between the upper and lower substrates, the space between the substrates can be kept constant without being affected by the external environment. As described above, the driving conditions of the fine particles are different depending on the moisture in the atmosphere, so it is necessary to keep the inside of the substrate in a constant state. Therefore, the step of bonding the two substrates is performed in an inert gas to prevent moisture in the air from entering the substrates, or after bonding the two substrates, By replacing air with an inert gas, the space between the substrates is filled with the inert gas.
As described above, by filling the space between the substrates with the inert gas, it is possible to provide a display device of a fine particle movement type having stable characteristics without being affected by the external environment.

Instead of filling with an inert gas, a vacuum may be applied between the pair of substrates. This also allows the space between the substrates to be kept constant without being affected by the external environment. Therefore, the space between the substrates can be evacuated by bonding the two substrates in a vacuum or by evacuating the substrates after bonding the substrates. As described above, even when the space between the substrates is evacuated, it is possible to provide a display device of a particle migration type having stable characteristics regardless of an external environment.

In the display element described so far, fine particles
White particles 4₁, Two-color display is possible
It is possible to provide a simple display element. For example, as shown in FIG.
As shown in FIG.
A non-pixel electrode 10 and a pixel electrode 11 are provided on
Particle 4₁To move the black and white depending on the size of the electrode
Display becomes possible. That is, the white fine particles 4₁Is non-pixel
When it moves on the pole 10 and does not exist on the pixel electrode 11
Indicates black, and white fine particles 4₁Is on the pixel electrode 11
If present, white is displayed. Such two-color display
Is white fine particles 4 ₁Is moved between the non-pixel electrode and the pixel.
White fine particles 4₁Coagulate and disperse
Can be realized even when the display state is changed by
It is. Further, when the back absorbing layer 17 is a colored layer,
Two-color display of the color of the absorption layer 17 and white can be performed.

[0066] In the display device according to the present invention, instead of the white fine particles as described above, by using a black fine particles 4 _2, it can be black and white display, two-color display and color display can obtain a display device capable . As shown in FIG. 22, the light shielding layers 6 and the diffuse reflection plates 18 are alternately provided on one substrate 1, and the non-pixel electrodes 10 are
The pixel electrode 11 is formed on the, moving the black particles 4 ₂ between a pair of substrates 1,14, monochrome display is performed. In other words, white is displayed when the black particles 4 ₂ is moved onto the non-pixel electrodes 10, the black particles 4 ₂ appears black when you move on the pixel electrode 11. in this case,
2-color display of black and white, not only when moving the black particles 4 ₂ between the non-pixel electrode and the pixel electrode, the black particles 4
It can also be realized by changing the display state by aggregating and dispersing ₂ . The display element shown in FIG.
By forming the substrate 1 as a transparent substrate and providing a white backlight 19 on the back of the substrate 1 as shown in FIG. 23, a transmissive display element can be obtained.

Further, two-color display can be performed by providing a colored layer 20 below the pixel electrode 10 as shown in FIG. 24 instead of the diffuse reflection plate 18 in the display element shown in FIG. It is. In this case, if the substrate 1 is a transparent substrate and a white backlight 19 is provided on the back surface of the substrate 1, a transmissive display element is obtained. If a diffuse reflection plate 18 is provided instead of the white backlight 19, a reflective display element is obtained. Further, a color display element using a combination of pixels of three colors of red, green, and blue can be prepared by appropriately arranging a red coloring layer, a green coloring layer, and a blue coloring layer.

[0068] Thus, a combination of the black fine particles 4 ₂ and the diffuse reflection plate 18 and the colored layer 20, by a display device having the structure shown in FIGS. 22 to 24, black and white display, two-color display and color Display can be performed, and furthermore, display in any of a transmission type and a reflection type can be realized.

In the display device shown in FIG. 22, a color filter 21 is arranged on a substrate 14 facing the substrate 1, and the monochrome display device 22 and the color filter 21 are combined to form a color display device having the structure shown in FIG. Can be realized. The monochrome display element 22 may use any of the display elements shown in FIGS. 21 to 24 described above. In the transmission type monochrome display element 22 as shown in FIG. 23, the color filter 21 may be provided below the pixel electrode 11. Thus, a color display element can be provided by combining the color filter 21 and the monochrome display element 22.

The white fine particles or the black fine particles have been described as examples of the fine particles 4 used in the display element according to the present invention. However, the color of the fine particles is not limited to white or black, and any color may be used. Colored fine particles may be used. Also in this case, a two-color display element can be realized. For example, in the display element shown in FIG. 22, when colored fine particles of any color are used instead of black fine particles, white is displayed when the colored fine particles move to the non-pixel electrode, and the colored fine particles move to the pixel electrode. Sometimes the color of the colored particles is displayed. In addition, instead of moving the colored fine particles between the non-pixel electrode and the pixel electrode, the colored fine particles are aggregated and dispersed on the pixel electrode to change the display state. can do.

The various display elements described so far have used electrodes having the same shape or two types of electrodes having different sizes. However, the electrode structure in each pixel may be a three-pole structure and driven independently in three phases. The reason is as follows. In the display element of the present invention, the movement of the fine particles is controlled in each pixel. As long as the pixels are adjacent to each other, as shown in FIG. 26, depending on the position of the fine particles and the polarity of the fine particles. There is a possibility that the electric field or the electrostatic force applied to the fine particles from adjacent pixels becomes symmetric.
In this case, the fine particles do not move at all or fly right above, although they should originally move in parallel, and display becomes impossible. Therefore, in order to move the fine particles as intended, it is necessary to adopt an electrode structure for each pixel which is not affected by an electric field or an electrostatic force from an adjacent pixel.

FIG. 27 shows an example of an electrode structure which is not affected by an electric field strength or an electrostatic force from an adjacent pixel. As shown in FIG.
3 is provided between the non-pixel electrode 10 and the pixel electrode 11,
The electrode has a three-pole structure. Thereby, the influence of the electric field or the electrostatic force from the adjacent pixels can be reduced, so that the fine particles 4 can be moved to a target position.
The auxiliary electrode 23 can normally perform the above function only by being grounded. However, depending on the position of the fine particles 4, by applying an electric field to the auxiliary electrode 23, the movement of the fine particles 4 is restricted or It is also possible to promote. As described above, by forming the electrodes in a three-phase structure, a highly reliable display element that can regulate the movement of the fine particles can be manufactured.

As described above, depending on the position of the fine particles and the polarity of the fine particles, the electrostatic force may be applied to the fine particles from adjacent pixels symmetrically. However, because the left and right electrostatic forces are equal, they do not move, or they fly just above due to only the vertical electrostatic force acting, and the original movement cannot be performed, making display impossible. Therefore, in order to realize the electrode structure which is not affected by the electric field or the electrostatic force of the adjacent pixels for each pixel by moving the fine particles as intended, the electrodes of the display element according to the present invention are referred to as non-pixel electrodes. It is desirable to arrange the electrodes so as to satisfy the distance between the pixel electrode and the distance between the pixel unit electrodes. Thereby, the moving direction of the fine particles can be defined. Here, the distance between the non-pixel electrode and the pixel electrode is the distance indicated by reference numeral 24 in FIG. 28, and the distance between the pixel unit electrodes is the distance between two adjacent pixels indicated by reference numeral 25 in FIG. It means the distance between adjacent electrodes.

In this manner, the arrangement of the electrodes is set so that the distance between the non-pixel electrode and the pixel electrode is smaller than the distance between the pixel unit electrodes, and the distance between the electrodes in one pixel and the distance between the adjacent pixels are reduced. By making the distance between the electrode and the electrode different, the influence of the electric field or electrostatic force of an adjacent pixel can be reduced, and the fine particles can be moved to a target position. By realizing such an electrode arrangement, fine particles can be reliably moved, and a highly reliable display element can be provided.

The above-described rib structure 16 is effective as a structure for reducing the influence from the adjacent pixels. Thereby, the moving direction of the fine particles can be defined. As described above, an electric field or electrostatic force is applied to the fine particles symmetrically depending on the position of the fine particles and the polarity of the fine particles, and the fine particles that should originally move in parallel do not move at all or fly directly above. As a result, the original display cannot be performed, and the intended display becomes impossible. In order to avoid this, as shown in FIG. 29, a rib structure 16 is arranged between pixels. This allows
Since the distance between the electrodes in one pixel and the distance between the electrodes of adjacent pixels can be made different, the influence of the electric field or electrostatic force by the adjacent pixels is reduced, and the fine particles are moved to the desired position. Can be moved.

The rib structure 16 can be made of any material such as an insulator or a conductor. Also, the rib structure 1
Reference numeral 6 is used for adjusting the intensity of the electric field formed by the adjacent pixels, so that the height may be approximately the same as that of the electrodes, and may also serve as a spacer for maintaining the distance between the upper and lower substrates.

Since the display element according to the present invention translates the fine particles in parallel by the electrostatic force, if the electrodes are electrically short-circuited by the charged fine particles, there is a possibility that ignition or disconnection may occur and the display element may not be formed. large.
Therefore, when producing a display element that moves by utilizing the charging of fine particles, it is desirable to form a protective film on the electrodes so that a short circuit between the electrodes does not occur. One example of the protective film is the insulating film 8 in FIG. Further, the material of the protective film is set so that the withstand voltage of the protective film at a point where the distance between the electrode on the substrate and the surface of the film over the substrate is the smallest is larger than the voltage applied between two adjacent electrodes. It is necessary to select the thickness and the thickness. With such a configuration, it is possible to prevent the electrodes from being electrically short-circuited by the charged fine particles after the film is formed on the electrodes.

As shown in FIG. 30, the thickness of the protective film at the step formed between the adjacent electrodes is smaller than that on the electrodes. In this case, if the withstand voltage of the thinnest portion is smaller than the voltage difference between the adjacent electrodes, when the fine particles move through such a stepped portion, if the arc condition is satisfied between the fine particles, dielectric breakdown occurs between the adjacent electrodes, and a large breakdown occurs. A current flows and the element is destroyed. Therefore, by giving a sufficient withstand voltage to such a thin portion, a highly reliable display element without dielectric breakdown can be obtained.

In the above description, only the step portion between the electrodes is taken as an example of the place where the thickness of the protective film is the thinnest. May be the thinnest part of

[0080]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the display device according to the present invention will be described below. However, the present invention is not limited to the following examples. In the following description, the same members will be designated by the same reference numerals, and the description thereof will be omitted.

Embodiment 1 FIG. 31 is a sectional view schematically showing the structure of a first embodiment of the display element according to the present invention. The display element 101 according to this embodiment includes a non-pixel electrode 53 and a pixel electrode 5 on one surface of a substrate 51 made of an insulating substrate via a back absorption layer 52.
4 and an electrode group including the auxiliary electrode 55 are formed. The non-pixel electrode 53 and the auxiliary electrode 55 are arranged in parallel with each other, and the pixel electrode 54 is arranged so as to be orthogonal to the non-pixel electrode 53. Further, an insulating film 56 is formed so as to cover these electrodes, and white fine particles 57 are disposed thereon. Thus, the fine particle moving substrate 81 is configured.

A color filter substrate 82 composed of a substrate 59 provided with a color filter 58 is provided opposite to the particle moving substrate 81. In order to hold the color filter substrate 82 at a fixed distance from the particle moving substrate 81, A rib structure 60 is provided for each pixel, and the periphery of the display element is further sealed by a sealing member 61.

The pair of upper and lower substrates 51 and 59 are supports for supporting various members, and are made of glass or plastic material, but need only be capable of supporting the members, and need not be hard materials. . However, in this example, the substrate 59 was transparent. Electrodes 53, 54,
55 is also transparent because the back absorption layer 52 is provided on the back surface. Therefore, the material of these electrodes is IT
O or tin oxide is used. However, the electrodes 53 to 5
When 5 also serves as the back absorption layer, these electrodes need not necessarily be transparent. Although the display element 101 in the first embodiment has a structure of a display element based on a simple matrix driving method, it may be an element corresponding to an active matrix driving method.

The insulating film 56 has a role of a protective layer for preventing leakage between electrodes and dielectric breakdown by the white fine particles 57. The white fine particles 57 pass through the insulating film 56 and pass through the electrode 5.
It is charged by the electric field applied to 3-55. The material of the insulating film 56 can be appropriately selected depending on the material of the fine particles 57 and the voltage applied to the electrode. For example, the insulating film 56 may be an inorganic material such as SiO ₂ , an organic material such as polycarbonate, or a hybrid material of an inorganic material and an organic material. The insulating film 56 is formed by an evaporation method,
Spin coating method, casting method, printing method, LB film method, etc.
It can be formed by any known method.

The back absorption layer 52 formed between the substrate 51 and the electrodes 53 to 55 is used as a light-shielding layer outside the respective pixels, and is used when the white fine particles 57 have not moved to the pixel electrodes 54. Used to display black. Therefore, when the white fine particles 57 move onto the pixel electrode 54, the color of the back absorption layer 52 is hidden, and white display is performed. As the back absorption layer 52, any material can be used as long as it can absorb light sufficiently, such as carbon black. In FIG. 31, the back absorption layer 52 is formed on the upper surface of the substrate 51.
1 may be installed on the lower surface.

The rib structure 60 for maintaining the distance between the fine particle moving substrate 81 and the color filter substrate 82 can be made of an inorganic material or an organic material by using a photolithography process. Note that the display element 101 shown in FIG.
In the above, between the two adjacent pixels and the electrode 53,
The rib structure 60 was formed in a stripe shape in parallel with 55. Instead, the rib structure 60 may be formed so as to surround each pixel or may be formed so as to be arranged on the non-pixel electrode 53, and the shape is arbitrary. In the display element 101, the rib structure 60 is formed on the insulating film 56. However, the rib structure 60 may be formed and then the insulating film 56 may be formed to cover the rib structure 60. good.

After the thus-prepared fine particle moving substrate 81 and color filter substrate 82 are integrated, the peripheral portion is sealed with a sealing member 61 to complete the display element 101. The sealing member 61 not only secures the fine particle moving substrate 81 and the color filter substrate 82 but also prevents moisture or the like from entering the inside, thereby keeping the internal environment constant. The sealing member 61 may be made of any resin material that is adhesive and does not transmit moisture.

Here, the manufacturing process of the display element 101 will be described with reference to FIGS. First, a back absorption layer 52 is formed on a transparent substrate 51 made of plastic,
On top of that, an ITP with a thickness of 1000
O was formed, and the non-pixel electrode 53 and the auxiliary electrode 55 were patterned in parallel by a photolithography process, as shown in FIG. In this case, it is desirable that the material of the substrate 51 be a material whose water absorption is suppressed and which is not eroded by a photolithography process (exposure, development, etching, etc.). Next, as shown in FIG. 32B, a thin insulating layer of a polycarbonate-based material is formed so as to cover these electrodes.
As shown in FIG. 32C, a transparent pixel electrode 54 was formed between the two electrodes by sputtering ITO.

As shown in FIG. 33, the pixel electrode 54 forms a stripe-shaped conductive portion at right angles to the non-pixel electrode 53 and the auxiliary electrode 55 formed on the substrate 51 in parallel with each other. It is formed by forming a region corresponding to the pixel electrode 54 from the conductive portion in a comb shape. Thus, the non-pixel electrode 53, the pixel electrode 54, and the auxiliary electrode 55
Was formed so that it could be taken out from the upper, lower, left and right sides of the substrate 51. An insulating film 56 was formed by spin coating so as to cover the electrodes 53, 54, and 55 thus obtained (FIG. 32D). The insulating film 56 is also made of a polycarbonate-based material. Thus, the fine particle moving substrate 81
Was formed.

The fine particle moving substrate 8 thus obtained
1, between the non-pixel electrode 53 and the pixel electrode 54, and
There is a step between the pixel electrode 54 and the auxiliary electrode 55,
Although the thinnest portion of the insulating film occurs here, these steps have a sufficient withstand voltage against the voltage applied to each electrode, and the presence of the fine particles did not cause an electrical short circuit.

Next, the non-pixel electrode 53 on the insulating film 56
In order to form the rib structure 60 between the electrode and the auxiliary electrode 55, a photosensitive acrylic resin was applied, and a projection having a height of 20 μm was formed by a photolithography process so as to be parallel to these electrodes. One example of an acrylic material is V259 series manufactured by Nippon Steel Chemical Co., Ltd. Acrylic white fine particles 57 having a diameter of 3 μm were dispersed between the rib structures 60 thus formed.

On the other hand, in order to form a color filter substrate 82, a color filter 58 was formed on a plastic transparent substrate 59. The color filter 58 includes the pixel electrode 54 and the colored layer 5 of the color filter 58 when the particle moving substrate 81 and the color filter substrate 82 are integrally bonded.
8 'overlapped. Note that a light-shielding layer was formed in a portion of the color filter 58 between adjacent colored layers. Thus, the color filter substrate 82 is completed,
After the fine particle moving substrate 81 and the color filter substrate 82 were aligned and bonded to each other, the periphery was sealed with an adhesive that does not transmit moisture, whereby the display element 101 was completed.

The bonding of the fine particle moving substrate 81 and the color filter substrate 82 was performed in a vacuum. Thereby, each pixel portion could be kept in a vacuum. At this time, if the object is placed in a vacuum while applying an electric field to a required electrode, the white fine particles 57 are fixed on the electrode, and the bonding can be performed without losing the white fine particles 57.

The bonding may be performed in a nitrogen atmosphere instead of in a vacuum. By bonding the fine particle transfer substrate 81 and the color filter substrate 82 in a nitrogen-substituted glove box, each pixel portion can be kept in a dry nitrogen atmosphere. As described above, when the electrodes are placed in a dry nitrogen atmosphere while applying an electric field to the required electrodes, the white fine particles 57 are fixed on the electrodes, so that the bonding can be performed without losing the white fine particles 57.

As described above, by placing each pixel portion in a vacuum or dry nitrogen atmosphere, the inside of the pixel can be maintained in a constant state even when the external environment changes. Could be provided. Note that a dry gas may be used instead of nitrogen if conditions such as withstand voltage and inertness are satisfied.

The display element 101 is an absorption-type display element because the rear absorption plate 52 is formed on the substrate 51. Therefore,
When a voltage having a required magnitude and polarity is applied to the non-pixel electrode 53, the pixel electrode 54, and the auxiliary electrode 55, when the non-pixel electrode 53 has white fine particles 57, the color of the back absorption layer 52 is changed through the pixel electrode 54. Since the display is performed, a black display is performed. If there is a white fine particle 57 on the pixel electrode 54,
Since the white fine particles 57 cover the back absorption layer 52, white display can be performed. The auxiliary electrode 55 and the rib structure 6
Since the moving direction of the white fine particles 57 can be defined by 0, the white fine particles 57 can move in parallel between the non-pixel electrode 53 and the pixel electrode 54.

Since the display element 101 does not use a polarizing plate as compared with a liquid crystal display element having the same pixel area, bright display was possible. In addition, compared to an electrophoretic display device using an insulating liquid layer, a display having a high white / black contrast ratio was able to be performed. In particular, in the black display, the display element 101 can absorb almost 100% of the incident light in the back absorption layer 52, so that a display with a low black level was possible.
Further, since the display element 101 has a memory property, the display state can be kept even after the application of the voltage to the electrodes is stopped. In addition, since the display element 101 does not use a solvent, there is no need to worry about liquid leakage and the like, and a highly reliable display element having excellent characteristics as compared with a conventional display element using fine particles can be manufactured. Was.

Embodiment 2 The structure of a display element according to a second embodiment of the present invention will be described with reference to FIG. The display element 102 in this embodiment is different from the display element 101 in the first embodiment in that a diffuse reflection plate 62 is provided instead of the back absorption layer 52 of the fine particle moving substrate 81, And the pixel electrode 5
Except for the portion 4, a fine particle moving substrate 83 on which the light shielding layer 63 is formed is used, and black fine particles 64 are used. As the black fine particles 64, acrylic resin fine particles having a diameter of 3 μm were used.

The display element 102 in the second embodiment is
Since the diffuse reflection plate 62 is employed, this is a reflection type display element. Then, when a voltage is applied to the non-pixel electrode 53 and the pixel electrode 54, when the black fine particles 64 are present on the non-pixel electrode 53, the pixel electrode 54 reflects the incident light by the lower diffuse reflection plate 62, so that white display is performed. I was able to. When the black fine particles 64 are on the pixel electrode 54, the pixel electrode 5
By covering 4 with black fine particles 64, the emitted light was absorbed and black display could be performed.

In the second embodiment, as in the first embodiment, the direction of movement of the black fine particles 64 can be defined by the auxiliary electrode 55 and the rib structure 60. It can move in parallel between the electrode 53 and the pixel electrode 54. Therefore, the display element 10
Sample No. 2 did not use a polarizing plate as compared with a liquid crystal display device having the same pixel area, so that bright display was possible. In addition, compared to an electrophoretic display device using an insulating liquid layer, a display having a high black-and-white contrast ratio could be performed. In particular, in the white display, the display element 102 can perform bright display by the diffuse reflection plate 62. Moreover, since the display element 102 has a memory property, the display state can be preserved even after the application of the voltage to the electrodes is stopped. Further, since the display element 102 does not use a solvent,
A highly reliable display element could be manufactured without concern for liquid leakage.

In the display element 102, if the diffuse reflection plate 62 is removed from the fine particle moving substrate 81, a transmission type display element can be formed. Light can be dimmed.

As described above, it was found that the display element 102 according to the second embodiment is a display element having characteristics superior to those of a conventional display element using fine particles. Embodiment 3 FIG. 35 is a sectional view schematically showing the configuration of a third embodiment of the display element according to the present invention. The display element 103 in this embodiment differs from the display element 102 in the second embodiment in that blue fine particles 65 are used instead of the black fine particles 64. The diameter of the blue fine particles 65 is 3
An acrylic resin-based fine particle of μm was used.

The display element 103 in the third embodiment is
Since the diffuse reflection plate 62 is employed, this is a reflection type display element. Therefore, when a voltage is applied to the non-pixel electrode 53 and the pixel electrode 54, when the blue fine particles 65 are present on the non-pixel electrode 53, the pixel electrode 54 reflects incident light by the lower diffuse reflection plate 62, so that white display is performed. I was able to. When the blue fine particles 65 are on the pixel electrode 54, the pixel electrode 5
4 was covered with blue fine particles 65 to absorb the emitted light and to perform blue display.

In the third embodiment, as in the first and second embodiments, the auxiliary electrode 55 and the rib structure 6 are formed.
Since the moving direction of the blue fine particles 65 can be defined by 0, the blue fine particles 65 can move between the non-pixel electrode 53 and the pixel electrode 54 in parallel. Therefore, the display element 102 did not use a polarizing plate as compared with a liquid crystal display element having the same pixel area, so that bright display was possible. In addition, compared to an electrophoretic display device using an insulating liquid layer, a display having a high black-and-white contrast ratio could be performed. Particularly in a white display, the display element 10
In No. 2, bright display by the diffuse reflection plate 62 was possible.
Moreover, since the display element 102 has a memory property,
The display state could be preserved even after the application of the voltage to the electrode was stopped. Further, since the display element 102 does not use a solvent, there is no fear of liquid leakage or the like, and a highly reliable display element can be manufactured.

In the display element 103, if the diffuse reflection plate 62 is removed from the fine particle moving substrate 81, a transmissive display element can be formed. Light can be dimmed.

As described above, it was found that the display element 103 of the third embodiment has a higher characteristic than the conventional display element using fine particles. Example 4 FIG. 36 is a sectional view schematically showing a configuration of a fourth embodiment of the display element according to the present invention. The display element 104 according to this embodiment is different from the display element 104 in that the charge transport film 6 is used instead of the insulating film 56.
6 is different from the display element 101 in the first embodiment in that a fine particle moving substrate 84 provided with a color filter 6 and a color filter substrate 85 in which a transparent electrode 67 is provided on the entire surface of the color filter 58 are used. .

As the white fine particles 57, fine particles of a conductive material having a diameter of 3 μm and charged by injection of electric charge were used. Further, as the charge transporting film 66, diethylaminobenzoaldehyde diphenylhydrazone as a hole transporting material is added to a polycarbonate resin as an insulating material in a weight ratio of 1: 1.
The materials mixed in 1 were used. The charge transport film 66 can transport holes to the white fine particles 57 when a positive voltage is applied to the non-pixel electrode 53 or the pixel electrode 54, and functions as an insulating film when a negative voltage is applied. Function. Therefore, the white fine particles 57 are always positively charged. Note that an electron transporting material may be used as the charge transporting film 66 instead of the hole transporting material. In this case, the white fine particles 57 are always negatively charged.

The display element 104 in the fourth embodiment is
This is an absorption type display element employing the back absorption layer 52. Therefore, when a voltage is applied to the non-pixel electrode 53 and the pixel electrode 54, when the white fine particles 65 are on the non-pixel electrode 53,
Since the pixel electrode 54 absorbs incident light by the lower back absorption layer 52, black display is performed. When white fine particles 57 are on the pixel electrode 54, white display is performed by covering the pixel electrode 54 with white fine particles 57. Could be done. Also in the fourth embodiment, similarly to the first to third embodiments, the moving direction of the white fine particles 57 can be defined by the auxiliary electrode 55 and the rib structure 60. Can move in parallel between the non-pixel electrode 53 and the pixel electrode 54. For this reason, the display element 104 did not use a polarizing plate as compared with a liquid crystal display element having the same pixel area, so that bright display was possible. In addition, compared to an electrophoretic display device using an insulating liquid layer, a display having a high black-and-white contrast ratio could be performed. Moreover, since the display element 104 has a memory property, the display state can be preserved even after the application of the voltage to the electrodes is stopped. Further, since the display element 104 does not use a solvent,
A highly reliable display element could be manufactured without concern for liquid leakage.

In the display element 104, a positive voltage was always applied to the electrode 67 formed on the opposing substrate 59. Due to the electric field formed by this, the positively charged white fine particles 57 receive a downward electrostatic force due to the electric field formed by the electrode 67, and the non-pixel electrode 53 and the pixel electrode 54
In the case of the parallel movement between the two, it was possible to move further parallel without flying toward the substrate 59 or drawing a parabola. Therefore, when the display element 104 is compared with the display element 101 in the first embodiment, in the first embodiment,
In some cases, the white particles 57 adhered to the substrate 59 side, though very slightly, due to repetitive driving, and the contrast was reduced. However, such a problem was caused in the display element 104 of the fourth embodiment. Thus, the desired contrast could be maintained.

Embodiment 5 FIG. 37 is a sectional view schematically showing a structure of a display element according to a fifth embodiment of the present invention. The display element 105 in this embodiment is the same as the display element 1 in the first embodiment described above.
The difference from the first embodiment is that a fine particle moving substrate 86 in which the rib structure 60 is provided on the non-pixel electrode 53 is used.

Since the rib structure 60 is formed on the non-pixel electrode 53, a material which is charged in accordance with the voltage applied to the non-pixel electrode 53 is used. As a result, the white fine particles 57 are adsorbed on the surface of the rib structure 60 when moving on the non-pixel electrode 53, and detach from the surface of the rib structure 60 when moving on the pixel electrode Move to 53.

The display element 105 in the fifth embodiment is
Since the back absorption layer 52 is provided, the display device is an absorption type display device. Then, when a voltage is applied to the non-pixel electrode 53 and the pixel electrode 54, when the white fine particles 57 are present on the surface of the rib structure 60, the pixel electrode 54 displays the color of the back absorption layer 52 and displays black. I was able to. On the other hand, white fine particles 5
When 7 was on the pixel electrode 54, the white fine particles 57 covered the pixel electrode 54, so that white display was performed by the white fine particles 57. Further, since the moving direction of the white fine particles 57 can be defined by the auxiliary electrode 55 and the rib structure 60, the white fine particles 57 can move in parallel between the non-pixel electrode 53 and the pixel electrode 54.

In the display element 105, since the rib structure 60 having a large surface area is provided on the non-pixel electrode 53, the width of the non-pixel electrode 53 can be reduced. Can be greatly increased, so that the aperture ratio of the display element can be improved by 10%. In addition, since the area for displaying the white fine particles 57 is also increased, the brightness during white display is improved, and the contrast can be improved by 10%. The rib structure 60
Of the non-pixel electrode 53 in the display element 101
Therefore, it is possible to use a larger amount of white fine particles 57 as compared with the first embodiment. On the other hand, if the amount of the white fine particles 57 is fixed, the width of the non-pixel electrode 53 can be reduced. Therefore, the contrast can be further improved.

Embodiment 6 FIG. 38 is a sectional view schematically showing a structure of a display element according to a sixth embodiment of the present invention. The display element 106 of this embodiment has the same structure as the fine particle moving substrate 81 as compared with the display element 101 of the first embodiment.
The non-pixel electrode 53 and the pixel electrode 5 having the same shape as the fine particle moving substrate 81 are provided on the color filter 58 of the color filter substrate 82.
4 and the auxiliary electrode 55 are formed, and the fine particle moving substrate 87 whose upper surface is covered with the insulating film 56 is used, and the white fine particles 57 are provided on the fine particle moving substrate 81 and the fine particle moving substrate 87, respectively. Is different. Thus, FIG.
As shown in (1), a display element having electrodes symmetrical with respect to a plane parallel to the substrate was prepared, and the same voltage was applied to each of the opposing electrodes.

The display element 106 is an absorption type display element because it has the back absorption layer 52. Therefore, the non-pixel electrode 5
3 and the pixel electrode 54, the rib structure 6
In the case where white fine particles 57 are present on the surface of
No. 4 displays the color of the back absorption layer 52, so black display was performed. On the other hand, when the white fine particles 57 were on the pixel electrode 54, the white fine particles 57 covered the pixel electrode 54, and white display was performed by the white fine particles 57. Further, the white fine particles 57 are formed by the auxiliary electrode 55 and the rib structure 60.
, The white fine particles 57 could move between the non-pixel electrode 53 and the pixel electrode 54 in parallel.

In particular, the display element 10 according to the sixth embodiment
In 6, white display is performed by the white fine particles 57 provided on each of the upper and lower fine particle moving substrates. Non-uniformity was eliminated by stacking a pair of fine particle moving substrates, and uniform white display could be performed over the whole of each pixel.

Further, in the sixth embodiment, since the same voltage is applied to the upper and lower opposing electrodes, the upper and lower white fine particles 57 receive the repulsive electrostatic force from the opposing substrates. For this reason, the white fine particles 57 can move in parallel without flying to the opposing substrate side or drawing a parabola. Since the particles are repelled by the electrodes on the opposite side, the movement of the fine particles can be controlled. Therefore, compared to the display element 101 of the first embodiment, in-plane non-uniformity and unevenness during white display are eliminated, and
Contrast improved.

Although the embodiments and examples of the display element according to the present invention have been described in detail, the present invention is not limited to these embodiments and examples. For example,
The case where only one kind of fine particles is used has been described so far. However, the present invention is not limited to this, and a plurality of kinds of fine particles having different colors can be simultaneously placed on the electrode to display a mixed color of those colors. You may do so. Also, in any of the embodiments and examples, the shape of the electrode formed on the substrate is arbitrary, and is not limited to the illustrated structure.

[0119]

As will be understood from the detailed description of the embodiments and examples of the display element according to the present invention, the invention of claim 1 is based on moving fine particles in a medium-free state. There is an effect that a highly reliable display element having good contrast can be provided.

According to the second aspect of the present invention, since a pair of substrates are provided, it is possible to provide a highly reliable display element which is hardly influenced by an external environment. According to the third aspect of the invention, since the electrodes having the same shape are formed on the pair of substrates, it is possible to provide a display element with improved contrast.

According to the invention of claim 4, it is possible to provide a display element having excellent reliability and display characteristics by keeping the distance between the pair of substrates constant by the structure and defining the moving direction of the fine particles. It works.

According to the fifth aspect of the present invention, since the structure is charged, it is possible to provide a display element having improved contrast by narrowing the non-pixel electrode.

According to a sixth aspect of the present invention, there is provided a display device having excellent reliability in which the peripheral portions of a pair of substrates are sealed, so that the insides of the substrates are kept constant without being affected by the external environment. This has the effect that it can be performed.

According to the seventh aspect of the present invention, since the insulating layer is formed on the electrode, it is possible to provide a display element in which fine particles are charged by an electric field to move the fine particles.

According to the eighth aspect of the present invention, since the charge transporting layer is formed on the electrode, it is possible to provide a display element in which a counter charge is injected into the fine particles by an electric field to charge the fine particles and move the fine particles. .

According to the ninth aspect of the present invention, the withstand voltage of the protective film at the point where the distance between the surface of the protective film and the electrode is the smallest is made higher than the voltage applied between the adjacent electrodes. This has the effect of providing a highly reliable display element free from defects.

According to the tenth aspect of the present invention, since the electrodes having different sizes are formed on the substrate, it is possible to provide a display element having a high contrast. According to the eleventh aspect of the present invention, the electrodes have a three-electrode structure and are driven in three phases independently, so that a display element having a good display characteristic in which the moving direction of the fine particles is defined can be provided.

According to a twelfth aspect of the present invention, the distance between the non-pixel electrode and the pixel electrode is made smaller than the distance between the electrode of the adjacent pixel and the display element having a good display characteristic by defining the moving direction of the fine particles. This has the effect that it can be provided.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a first embodiment of a display element according to the present invention.

FIG. 2 is a diagram for explaining dispersion and aggregation of fine particles in the display element of FIG. 1;

FIGS. 3A and 3B are diagrams showing a modification of the display device of FIG. 1;

FIG. 4 is a view schematically showing a display element according to a second embodiment of the present invention.

FIGS. 5A and 5B are diagrams illustrating parallel movement of fine particles in the display device of FIG. 4;

FIG. 6 is a view schematically showing a third embodiment of the display element according to the present invention.

FIGS. 7A and 7B are diagrams for explaining parallel movement of fine particles in the display device of FIG. 6;

FIG. 8 is a view schematically showing a fourth embodiment of the display element according to the present invention.

9 is a diagram showing a modification of the electrodes of the display element in FIG.

FIG. 10 is a diagram showing another modification of the electrodes of the display element in FIG.

FIG. 11 is a diagram for explaining undesired behavior of fine particles due to an electric field.

FIG. 12 is a view schematically showing a fifth embodiment of the display element according to the present invention.

FIGS. 13A and 13B are diagrams schematically showing a state in which a pixel electrode is not covered with fine particles.

FIG. 14 is a drawing schematically showing a sixth embodiment of the display element according to the present invention.

15 is a diagram showing another example of the electrode arrangement in the display element shown in FIG.

FIG. 16 is a view schematically showing a seventh embodiment of the display element according to the present invention.

17A and 17B are diagrams showing another structure of the rib structure in the display element of FIG.

18 is a diagram showing an example in which electric charges are applied to a rib structure in the display element of FIG.

FIG. 19 is a view showing another example of the rib structure in the display element of FIG. 16;

20 is a diagram showing another example of the rib structure in the display element of FIG.

FIG. 21 is a diagram illustrating white and black display operations of the display element according to the present invention when using white fine particles.

FIG. 22 is a diagram illustrating white and black display operations of the display element according to the present invention when using black fine particles.

FIG. 23 is a view showing a modification of the display element shown in FIG. 22 provided with a backlight.

FIG. 24 is a view showing a modification of the display element shown in FIG. 22 using a colored layer.

FIG. 25 is a diagram showing a color display element composed of a combination of the black and white display element shown in FIG. 22 and a color filter.

FIG. 26 is a diagram illustrating the effect of an electric field or electrostatic force of an adjacent pixel on fine particles.

FIG. 27 is a view showing a modification of the display element according to the present invention, provided with auxiliary electrodes.

FIG. 28 is a diagram illustrating a preferred arrangement of electrodes in the display element of the present invention.

FIG. 29 is a view for explaining the effect of the rib structure in the display element of the present invention for reducing the influence of adjacent pixels.

FIG. 30 is a diagram illustrating the relationship between the film thickness of an insulating layer or a charge transport layer and the withstand voltage in the display element of the present invention.

FIG. 31 is a view schematically showing a first embodiment of a display element according to the present invention.

32 (a) to (d) are views showing a process for manufacturing the display element of FIG. 31.

FIG. 33 is a plan view showing an arrangement relationship of various electrodes in the display element of FIG. 31.

FIG. 34 is a drawing schematically showing a second embodiment of the display element according to the present invention.

FIG. 35 is a drawing schematically showing a third embodiment of the display element according to the present invention.

FIG. 36 is a view schematically showing a fourth embodiment of the display element according to the present invention.

FIG. 37 is a drawing schematically showing a fifth embodiment of the display element according to the present invention.

FIG. 38 is a drawing schematically showing a sixth embodiment of the display element according to the present invention.

FIG. 39 is a diagram showing an example of a conventional fine particle transfer type display element.

FIG. 40 is a view showing another example of a conventional fine particle transfer type display element.

FIG. 41 is a view showing another example of a conventional fine particle moving display element.

FIG. 42 is a diagram illustrating a conventional powder moving device.

[Explanation of symbols]

1: substrate, 2, 2 ₂₁ to _8: electrode, 4: microparticles,
5: electrode, 6,6 _{1-6 3:} the light-shielding layer, 7: reflector,
8: insulating film, 9: charge transport film, 10: non-pixel electrode,
11: pixel electrode, 14: counter substrate, 16: rib structure, 17: back absorption layer, 18: diffuse reflection plate, 1
9: white backlight, 20: coloring layer, 21: color filter, 22: monochrome display element, 23: auxiliary electrode, 51: substrate, 52: back absorption layer, 53: non-pixel electrode, 54: pixel electrode, 55: Auxiliary electrode, 56: insulating film, 57: white fine particles, 58: color filter,
59: substrate, 60: rib structure, 61: sealing member, 62: diffusion reflector, 63: light shielding layer, 64: black fine particles, 65: colored fine particles, 66: charge transport film,
67: electrode, 81, 83, 84, 86, 87: fine particle moving substrate, 82, 85: color filter substrate, 10
1, 102, 103, 104, 105, 106: display element

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yoshihiro Sakaoka 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation

Claims (12)

[Claims] A first substrate having an insulating property; a first electrode formed on the substrate; and at least one kind of fine particles disposed on the first electrode. A display device, wherein the fine particles are moved in parallel with the first substrate in a medium-free state by a voltage applied to the electrode. A second electrode disposed on the first substrate at a predetermined distance from the first substrate; and a second electrode formed on the second substrate;
A display element, wherein the fine particles are moved with respect to the first substrate and the second substrate without a medium by a voltage applied between the first electrode and the second electrode. . 3. The display device according to claim 2, wherein the first electrode and the second electrode have the same shape. 4. The display device according to claim 2, wherein a structure that partitions pixels is formed between the first substrate and the second substrate. 5. The display device according to claim 4, wherein the structure is charged. 6. A sealing member according to claim 2, further comprising a sealing member for sealing a peripheral portion between said first substrate and said second substrate to prevent permeation of moisture. A display element according to any one of the above. 7. The display element according to claim 2, wherein an insulating film is formed on the first electrode. 8. The display device according to claim 21, wherein a charge transport film is formed on said first electrode. 9. A protection film is formed on the first electrode, and the withstand voltage of the protection film at a position where the distance between the surface of the protection film and the first electrode is the shortest is adjacent to each other. The display element according to claim 2, wherein the voltage is higher than a voltage applied between the first electrodes. 10. The method according to claim 2, wherein the first electrodes having different sizes are formed on the first substrate.
10. The display element according to any one of claims 9 to 9. 11. The semiconductor device according to claim 11, wherein the first electrode has a three-electrode structure.
The display element according to claim 2, wherein the display element is driven independently. 12. The pixel according to claim 1, wherein the first electrode in one pixel includes a non-pixel electrode and a pixel electrode, and the plurality of pixels are arranged such that the non-pixel electrode and the pixel electrode are alternately arranged. Wherein a distance between the non-pixel electrode and the pixel electrode is smaller than a distance between the pixel electrode in one pixel and the non-pixel electrode in a pixel adjacent to the pixel. 12. The display element according to any one of 2 to 11.