WO2009045065A2

WO2009045065A2 - Display device driven by electric filed

Info

Publication number: WO2009045065A2
Application number: PCT/KR2008/005819
Authority: WO
Inventors: Dae-Jung Jeong; Byung-Seong Bae; Chun-Hyuk Lee; Byung-Uk Kim; Mun-Pyo Hong
Original assignee: Dongjin Semichem Co Ltd
Current assignee: Dongjin Semichem Co Ltd
Priority date: 2007-10-05
Filing date: 2008-10-02
Publication date: 2009-04-09
Anticipated expiration: 2010-04-05
Also published as: TW200933233A; KR20090035228A; WO2009045065A3

Abstract

A display device that is driven by an electric field according to the present invention includes a first substrate, a second substrate that faces the first substrate, a first electrode that is formed on the first substrate, a contact electrode that is formed on the first electrode, a second electrode that is formed on the second substrate, and a wall that is disposed between the contact electrode and the second electrode. The contact electrode includes an opening through which the first electrode is exposed. In addition, the wall forms a driving area, and a driving body is disposed in the driving area. Thereby, an electrostatic characteristic of the driving body may be constantly maintained, and an image of the display device that is driven by an electric field may be precisely controlled.

Description

[SPECIFICATION] [INVENTION TITLE]

DISPLAY DEVICE DRIVEN BY ELECTRIC FILED [Technical Field] The present invention relates to a display device. More particularly, the present invention relates to a display device that is driven by an electric field. [Background Art]

Display devices that are extensively used include a liquid crystal display device, a plasma display panel, and an organic electroluminescence display device.

A liquid crystal display device is a display device that realizes an image by using electro-optical characteristics of liquid crystal in which light transmittance varies according to the application of an electric field, and a viewing angle is narrow and the liquid crystal display device is high in terms of cost. The plasma display device is a device that realizes an image by using plasma that is generated by discharging of gas, and much heat is generated from the panel because the discharging gas has a high temperature. An organic light emitting display device is a display device that emits light when exitons generated by injecting electrons and holes from a cathode (electron injection electrode) and an anode (hole injection electrode) into an organic light emitting layer and bonding the electrons and the holes fall from an excitation state to a base state. In the display device, only a portion of the injected charge is used to emit light and the remaining is lost as heat.

Meanwhile, as display devices that are extensively used, there are a i field emission display in which electrons are discharged from an emitter provided at a cathode by using a quantum mechanic tunneling effect and the discharged electrons collide with a fluorescent body provided at an anode to excite the fluorescent body, thus realizing a predetermined image, and an electrophoretic display in which pictures or letters are capable of being repeatedly displayed or removed by using an electrophoresis phenomenon.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. [DETAILED DESCRIPTION]

[Technical Problem]

The present invention provides a novel display device that is different from known display devices, and that is driven by an electric field. [Technical Solution]

A display device that is driven by an electric field according to an exemplary embodiment of the present invention includes i) a first substrate, ii) a second substrate that faces the first substrate, iii) a first electrode that is formed on the first substrate, iv) a contact electrode that is formed on the first electrode and includes an opening through which the first electrode is exposed, v) a second electrode that is formed on the second substrate, vi) a wall that is disposed between the contact electrode and the second electrode and forms a driving area, and vii) a driving body that is disposed in the driving area.

The opening and the driving area may be formed to be connected to each other.

The display device that is driven by an electric field may further include an insulating film that is disposed between the first electrode and the contact electrode and has a hole, and the hole may be formed to be connected to the opening.

The contact electrode may include a first metal layer having a first opening, and a second metal layer that is disposed on the first metal layer and has a second opening. The first metal layer may include aluminum or molybdenum, and the second metal layer may include nickel. Cross-sections of the first opening and the second opening may have a circular shape, and the diameter of the first opening may be larger than the diameter of the second opening.

The driving body may have a spherical shape, and the diameter of the driving body may be the same as or larger than the diameter of the second opening.

The contact electrode may be made of an opaque material. The contact electrode may be directly connected to the first electrode, and the same voltage as that applied to the first electrode may be applied to the contact electrode. The display device that is driven by an electric field may further include a blocking part that is disposed between the first substrate and the contact electrode.

The area of the cross-section of the driving area may be reduced while going away from the first substrate. The display device that is driven by an electric field may further include a color filter that is formed on the second substrate.

The first electrode and the second electrode may include a transparent conductive material or a metal oxide. The driving body has any one color that may be selected from the group consisting of black, white, red, green, blue, yellow, magenta, and cyan.

At least one of an inert gas, nitrogen, and dry air may be filled in the driving area. The driving area may be in a vacuum state.

The display device that is driven by an electric field may further include a backlight unit that provides light for display of the first and second substrates. The backlight unit may include a lamp emitting light and a light guide plate that converts the light emitted from the lamp into surface light. The backlight unit may further include a condenser lens that condenses the light emitted from the lamp and the light guide plate into the driving area. The display device that is driven by an electric field may further include a switching device that is formed on the first substrate and connected to the first electrode, and that controls a voltage applied to the first electrode. The switching device may include a thin film transistor.

A method for manufacturing a display device that is driven by an electric field according to an exemplary embodiment of the present invention includes the steps of forming a first electrode on a first substrate, forming an insulating film that has a hole through which the first electrode is exposed on the first substrate, forming a contact electrode that has an opening on the insulating film, forming a wall that defines a driving area on the contact electrode, injecting a driving body into the driving area by using a nanotip, and bonding the second substrate on which a second electrode is formed to the wall.

The forming of the contact electrode may include forming a first metal layer that has a first opening on the insulating film, and forming a second metal layer that has a second opening on the first metal layer. [Advantageous Effects]

According to the present invention, the position of the driving body may be controlled by using the force of gravity and the electric force, and by controlling the amount of passing light through in this way, a desired image may be displayed.

In addition, according to the present invention, due to the contact electrode, since the electrostatic characteristics of a plurality of driving bodies are constantly maintained, the position of the driving body may be precisely controlled. Thereby, the amount of light passing through the display panel may be more precisely controlled, and the high quality image may be realized.

[Brief Description of the Drawings]

FIG. 1 is a cross-sectional view of a display device that is driven by an electric field according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of a display device that is driven by an electric field according to another exemplary embodiment of the present invention.

FIG. 3 is a cross-sectional view that illustrates the driving of the display device that is driven by an electric field shown in FIG. 1. FIGS. 4A to 4E are views that sequentially illustrate a manufacturing process of the display device that is driven by an electric field shown in FIG. 1. [Best Mode]

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the specification. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

Now, a display device that is driven by an electric field according to an exemplary embodiment of the present invention will be described with reference to FIG. 1.

With reference to FIG. 1 , a display device 10 that is driven by an electric field includes a display panel 100 and a backlight unit 400.

The display panel 100 is a portion that displays an image by controlling the amount of light, and includes a lower substrate 110 on which a pixel electrode 120 is formed, an upper substrate 210 on which a common electrode

270 is formed, a wall 330 that forms a driving area 335, and a driving body 370 that is disposed in the driving area 335. The pixel electrodes 120 extending in one direction are arranged parallel to each other on the transparent lower substrate 110 that is made of glass or the like. The pixel electrode 120 may be made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

In addition, a switching device 130 for individually switching the voltage that is applied to each pixel electrode 120 is formed on the lower substrate 110, and the switching device 130 is connected to the pixel electrode 120. As the switching device 130, a thin film transistor may be used, and in this case, a gate line (not shown) that transfers an injection signal for performing on-off of the thin film transistor and a data line (not shown) that transfers a gray voltage applied to the pixel electrode 120 may be formed on the lower substrate 110 while crossing each other. The thin film transistor may include a gate electrode, a source electrode, a drain electrode, and a semiconductor.

On the lower substrate 110 and the switching device 130, a first insulating film 150 is formed. On the first insulating film 150, a first hole 155 is formed to expose the pixel electrode 120. The first insulating film 150 may have a single organic film structure and photosensitivity. The first insulating film 150 may be made of an inorganic film such as silicon nitride and silicon oxide, and may have a dual-film structure of an inorganic film and an organic film.

On the first insulating film 150, a contact electrode 170 is formed. The contact electrode 170 includes a first metal layer 170p having a first opening 175p and a second metal layer 17Oq having a second opening 175q. In addition, the contact electrode 170 is made of an opaque material in order to shield light. Cross-sections of the first opening 175p and the second opening 175q have a circular shape. However, the shapes of the cross-sections of the first opening 175p and the second opening 175q may vary according to the shape of the driving body 370. Meanwhile, the contact electrode 170 may be formed of two or more metal layers.

The first metal layer 17Op is formed directly on the first insulating film 150, and the first opening 175p of the first metal layer 17Op is formed to be connected to the first hole 155. The first metal layer 17Op made be made of a metal such as aluminum (Al) and molybdenum (Mo). The second metal layer 17Oq is formed directly on the first metal layer

17Op. In addition, a second opening 175q of a second metal layer 17Oq is formed to be connected to the first opening 175p. However, the diameter of the second opening 175q is smaller than the diameter of the first opening 175p. The second metal layer 17Oq may be made of a metal such as nickel. The contact electrode 170 is connected to independent wiring (not shown) and receives a voltage therefrom. The contact electrode 170 that receives a voltage applies the voltage to the driving body 370. The size of the voltage that is applied to the contact electrode 170 may be the same as or similar to the size of the voltage applied to the pixel electrode 120, and the polarity of the voltage applied to the contact electrode 170 may be the same as or opposite to the polarity of the voltage applied to the pixel electrode 120. The size of the voltage may vary according to the design of the display device 10, and the polarity of the voltage may be selected according to the moving direction of the driving body 370. Meanwhile, the contact electrode 170 may be directly connected to the pixel electrode 120 and the common electrode 270 and receive a voltage from the pixel electrode 120 and the common electrode 270.

The contact electrode 170 having the above structure may shield light passing through the lower substrate 110. Therefore, the contact electrode 170 acts as a blocking part. In addition, the contact electrode 170 may apply a voltage to the driving body 370 to constantly maintain the electrostatic characteristics of the driving body 370, thus precisely controlling the position of the driving body 370. In the present exemplary embodiment, the contact electrode 170 is formed of dual layers of the first and second metal layers 170p and 17Oq, but as shown in FIG. 2, the contact electrode 170 may be formed of a single layer. In addition, between the lower substrate 110 and the first insulating film 150, the blocking part 140 may be formed, and the blocking part 140 is formed so as to not overlap the pixel electrode 120. The blocking part 140 prevents the mixing of light between the adjacent pixels. In the structure of FIG. 2, since the blocking part 140 is present, the contact electrode 170 may be made of the transparent material such as ITO or IZO.

On the second metal layer 17Oq, a second insulating film 180 is formed. On the second insulating film 180, a second hole 185 that is connected to the second opening 175q and exposes a portion of the second metal layer 17Oq adjacent to the second opening 175q is formed. The second insulating film 180 may have a single organic film structure and photosensitivity. The first insulating film 150 may be made of an inorganic film such as silicon nitride and silicon oxide and have a dual-film structure of an inorganic film and an organic film.

On the second insulating film 180, a wall 330 that defines a plurality of driving areas 335 is formed. Each driving area 335 is connected to the second hole 185 of the second insulating film 180. The wall 330 may be formed by coating, exposing, and developing the photosensitive material. The wall 330 may be formed of an opaque material through which light cannot pass. For example, the wall 330 may be formed of a black color material, and prevents passing of unnecessary light through the wall 330 or deterioration of the display quality by reflection by the wall 330. The cross-section of the driving area 335 is circular, and the area of the cross-section of the driving area may be reduced while going away from the lower substrate 110 in an upper substrate 210 direction. That is, the driving area 335 has a truncated circular cone shape. The area of the cross-section of the driving area 335 may be increased while going away from the lower substrate 110 in the upper substrate 210 direction. In this case, the driving area 335 has a truncated circular cone shape that is turned upside down.

In the driving area 335 and the second hole 185, a spherical driving body 370 that has a position determined by electric force is disposed. The driving body 370 has a positive or negative charge. The driving body 370 may be formed in a multi-layered structure. For example, the outer side of the driving body 370 may be formed of an organic film for preserving the charge, and the inner side thereof may be formed of a metal layer for total reflection of light. In addition, the driving body 370 may be formed of an opaque material in order to exclude reflecting light.

The diameter of the driving body 370 is the same as or larger than the diameter of the second opening 175q. Therefore, the driving body 370 may freely move in a space of the driving area 335 and the second hole 185, but not to the lower part of the second metal layer 17Oq. If the driving body 370 blocks the second opening 175q by attractive force of the pixel electrode 120 and the contact electrode 170, light emitted from the backlight unit 400 is blocked, thereby realizing a perfect black state. Since the position of the driving body 370 is controlled by the pixel electrode 120, the common electrode 270, and the contact electrode 170, the position thereof may be precisely controlled.

An inert gas such as argon, neon, helium, and the like is contained in the driving area 335 in conjunction with the driving body 370. Instead of the inert gas, another gas such as nitrogen or dry air, which is suitable to preserve the charge of the driving body 370, may be contained. In addition, the driving area 335 may be maintained in a vacuum state.

The upper substrate 210 is bonded to the wall 330.

On the upper substrate 210, color filters 230 of red, green, and blue for realizing a color image are formed, and a third insulating film 250 for protecting them is formed on the color filters 230. In addition, a common electrode 270 is formed on the third insulating film 250. A fourth insulating film 280 for protecting it is formed on the common electrode 270. The third insulating film 250 and the fourth insulating film 280 may be formed of the organic film and the like, and the common electrode 270 may be formed of a transparent conductor such as ITO, IZO, and the like.

The backlight unit 400 is a part that provides light to the display panel 100 and includes a lamp 420, a light guide plate 410 that converts light emitted from that the lamp 420 that is a linear or dot light source into surface light, and a condenser lens 430 that collects light emitted from the light guide plate 410 and provides it a driving area 335 that is a display region. As the lamp 420, a linear light source such as a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and the like, or a dot light source such as a light emitting diode (LED) and the like may be used. In addition, the surface light source may be used, and in this case, the light guide plate 410 may be omitted. In addition, the condenser lens 430 may be directly formed on the surface of the light guide plate 410 or in a single layer, or in a separate film form, or in a single layer form on a side of the display panel 100. The backlight unit 400 may be disposed on either one of the lower substrate 110 and the upper substrate 210.

This display device that is driven by an electric field moves the position thereof by applying an electric force to the driving body 370 included in the driving area 335, and displays a desired image by controlling the amount of light provided from the backlight unit 400 in this way.

Now, the driving of the display device 10 that is driven by an electric field having the above structure will be described with reference to FIG. 3. In the display device 10 according to the present exemplary embodiment, the area of the driving area 335 through which light provided from the backlight unit 400 is capable of passing depends on the position of the driving body 370. That is, when the driving body 370 contacts the common electrode 270, the area of the driving area 335 through which light is capable of passing is maximized, the area through which light is capable of passing is reduced as the driving body 370 rolls down along the inclined side, and when the driving body 370 blocks the second opening 175q, light is completely blocked. As described above, the amount of light toward the upper substrate 210 is controlled according to the position of the driving body 370 in the driving area 335.

The position of the driving body 370 may be controlled by controlling the sizes and the polarities of the contact electrode 170, the pixel electrode 120 and the common electrode 270. For example, if the polarities of the voltages that are applied to the contact electrode 170 and the pixel electrode 120 are the same and the polarity of the voltage that is applied to the common electrode 270 is opposite to that of the contact electrode 170 and the pixel electrode 120, the driving body 370 may move in a common electrode 270 direction. On the contrary, if the polarities of the voltages that are applied to the contact electrode 170 and the pixel electrode 120 are different and the polarity of the voltage that is applied to the common electrode 270 is the same as that of the contact electrode 170, the driving body 370 may move in a contact electrode 170 direction. The intensity of the voltage that is applied to the contact electrode 170, the pixel electrode 120, and the common electrode 270 is in the range of 0.5 V to 5 V, and may vary according to the size of the display device 10 and the purpose of the design. The intensity of the voltage that is applied to the contact electrode 170, the pixel electrode 120, and the common electrode 270 is not limited to the above values.

Meanwhile, the driving body 370 may be driven by the electric force according to the contact electrode 170, the pixel electrode 120, and the common electrode 270 and the force of gravity. In general, the display device is used while a display image is almost vertically with respect to a horizontal surface. Therefore, the circumferential surface of the wall 300 that forms the driving area 335 forms an inclined surface with respect to the horizontal surface. The driving body 370 that is disposed on the inclined surface rolls down along the inclined surface due to the force of gravity in a contact electrode 170 direction. In the present exemplary embodiment, the second hole 185 of the second insulating film 180 is different from the circumferential surface of the wall 330 circumference in an inclined direction. However, in order to move the driving body 370 by using the force of gravity, the second hole 185 may be formed in the same direction as the circumferential surface of the wall 330. Accordingly, the driving body 370 rolls down the circumferential surface of the wall 330 and the second hole 185 to approach the contact electrode 170. On the other hand, if the voltage is applied to the common electrode 270, the pixel electrode 120, and the contact electrode 170, an electric field is formed between them, and the driving body 370 having the charge receives the electric force to overcome the force of gravity and roll upward to move in a common electrode 270 direction. As described above, when the driving body 370 moves in a contact electrode 170 direction, the force of gravity is used, and when it moves in a common electrode 270 direction, the electric force according to the contact electrode 170, the pixel electrode 120, and the common electrode 270 may be used. The circumferential surface of the wall 330 that forms the driving area

335, as shown in FIG. 3, may have a predetermined slope, and the slope thereof may be gradually increased while going upward. In addition, according to the angle of the circumferential surface with respect to the horizontal surface, since the size of the force of gravity force is applied to the driving body 370 varies, for each case, the driving voltage that is applied to the common electrode 270, the pixel electrode 120, and the contact electrode 170 may be appropriately determined.

Thus far, the method for controlling the amount of light by controlling the position in the driving area 335 of the driving body 370 has been described, but unlike this, by controlling the time where the driving body 370 blocks light, the amount of light may be controlled.

Here, since the size of the driving body 370 is in the range of several micrometers to several tens of micrometers, it may be driven at a voltage in the range of several tens of milivolts (mV) to several volts (V), and since it is operated at a very high speed, a display device wherein the response speed is very high and precise controlling is possible may be provided. Since the operation speed of the driving body 370 is inversely proportional to its weight, the driving body 370 may be formed to have a cavity to reduce its weight. In the structure that is shown in FIG. 3, since the common electrode 270, the pixel electrode 120, and the contact electrode 170 form the electric field, the position of the driving body 370 may be more precisely controlled.

Meanwhile, a display device that is driven by an electric field may not include the backlight unit 400 but may display an image by using external light, unlike the display device 10 that is driven by an electric field that is shown in FIG. 1. This display device that is driven by an electric field controls the amount of external light that reflects from the driving body to realize an image. If the driving body is closest to the upper substrate, light that is incident from the outside may totally reflect from the driving body, and if the driving body is spaced apart from the upper substrate by a predetermined distance, since only a portion of the light that is incident from the outside reflects from the driving body, a middle gray is displayed. In addition, if the driving body is farthest apart from the upper substrate, the light that is incident from the outside is almost not reflected. In this way, by controlling the position of the driving body in the driving area, an image may be displayed. In this case, the driving body may have any one color that is selected from the group consisting of white, red, green, blue, yellow, magenta, and cyan, thereby realizing various color images.

Next, a method for manufacturing a display device that is driven by an electric field according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 4A to 4E.

FIGS. 4A to 4E are views that sequentially illustrate a manufacturing process of the display device 10 that is driven by an electric field shown in FIG. 1. First, as shown in FIG. 4A, a pixel electrode 120 and a switching device 130 are formed on a lower substrate 110 that is made of a transparent insulating material such as glass, plasties, and the like. The switching device 130 may be a thin film transistor. In this case, a gate line, a data line having a source electrode, a drain electrode, and a semiconductor are formed on a lower substrate 110.

Next, as shown in FIG. 4B, structures of the first insulating film 150, the first metal layer 17Op, the second metal layer 17Oq, and the second insulating film 180 are sequentially layered on the lower substrate 110, the pixel electrode 120, and the switching device 130. The first and second insulating film 150 and 180 are single films of the organic film.

Next, as shown in FIG. 4C, by etching the structures, the second hole 185, the second opening 175q, the first opening 175p, and the first hole 155 are formed. These expose the pixel electrode 120. Next, as shown in FIG. 4D, a wall 330 that defines a plurality of driving areas 335 is formed, and the driving body 370 is injected into the plurality of driving areas 335. The driving body 370 is injected by using the nanotip.

Next, as shown in FIG. 4E, the color filter 230, the third insulating film

250, and the upper substrate 210 on which the common electrode 270 is formed are combined with each other to produce the display panel 100, and the backlight unit 400 is combined with the lower substrate 110 to produce the display device 10 that is driven by an electric field. As described above, according to an exemplary embodiment of the present invention, the position of the driving body may be controlled by using the force of gravity and the electric force, and by controlling the amount of passing light through in this way, a desired image may be displayed. In addition, according to an exemplary embodiment of the present invention, due to the contact electrode, since the electrostatic characteristics of a plurality of driving bodies are constantly maintained, the position of the driving body may be precisely controlled. Thereby, the amount of light passing through the display panel may be more precisely controlled, and the high quality image may be realized.

While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

[CLAIMS]

1. A display device that is driven by an electric field, comprising: a first substrate; a second substrate that faces the first substrate; a first electrode that is formed on the first substrate; a contact electrode that is formed on the first electrode and includes an opening through which the first electrode is exposed; a second electrode that is formed on the second substrate; a wall that is disposed between the contact electrode and the second electrode and forms a driving area; and a driving body that is disposed in the driving area.

2. The display device that is driven by an electric field of claim 1 , wherein the opening and the driving area are formed to be connected to each other.

3. The display device that is driven by an electric field of claim 2, further comprising an insulating film that is disposed between the first electrode and the contact electrode and has a hole, wherein the hole is formed to be connected to the opening.

4. The display device that is driven by an electric field of claim 1 , wherein the contact electrode includes a first metal layer having a first opening, and a second metal layer that is disposed on the first metal layer and has a second opening.

5. The display device that is driven by an electric field of claim 4, wherein the first metal layer includes aluminum or molybdenum, and the second metal layer includes nickel.

6. The display device that is driven by an electric field of claim 4, wherein cross-sections of the first opening and the second opening have a circular shape, and the diameter of the first opening is larger than the diameter of the second opening.

7. The display device that is driven by an electric field of claim 6, wherein the driving body has a spherical shape, and the diameter of the driving body is the same as or larger than the diameter of the second opening.

8. The display device that is driven by an electric field of claim 1 , wherein the contact electrode is made of an opaque material.

9. The display device that is driven by an electric field of claim 1 , wherein the contact electrode is directly connected to the first electrode, and the same voltage as that applied to the first electrode is applied to the contact electrode.

10. The display device that is driven by an electric field of claim 1 , further comprising a blocking part that is disposed between the first substrate and the contact electrode.

11. The display device that is driven by an electric field of claim 1 , wherein the area of the cross-section of the driving area is reduced while going away from the first substrate.

12. The display device that is driven by an electric field of claim 1 , further comprising a color filter that is formed on the second substrate.

13. The display device that is driven by an electric field of claim 1 , wherein the first electrode and the second electrode include a transparent conductive material or a metal oxide.

14. The display device that is driven by an electric field of claim 1 , wherein the driving body has any one color that is selected from the group consisting of black, white, red, green, blue, yellow, magenta, and cyan.

15. The display device that is driven by an electric field of claim 1 , wherein at least one of an inert gas, nitrogen, and dry air is filled in the driving area.

16. The display device that is driven by an electric field of claim 1 , wherein the driving area is in a vacuum state.

17. The display device that is driven by an electric field of claim 1 , further comprising a backlight unit that provides light for display of the first and second substrates.

18. The display device that is driven by an electric field of claim 17, wherein the backlight unit includes a lamp emitting light and a light guide plate that converts the light emitted from the lamp into surface light.

19. The display device that is driven by an electric field of claim 18, wherein the backlight unit further includes a condenser lens that condenses the light emitted from the lamp and the light guide plate into the driving area.

20. The display device that is driven by an electric field of claim 1 , further comprising a switching device that is formed on the first substrate and connected to the first electrode, and that controls a voltage applied to the first electrode.

21. The display device that is driven by an electric field of claim 20, wherein the switching device includes a thin film transistor.

22. A method for manufacturing a display device that is driven by an electric field, the method comprising the steps of: forming a first electrode on a first substrate; forming an insulating film that has a hole through which the first electrode is exposed on the first substrate; forming a contact electrode that has an opening on the insulating film; forming a wall that defines a driving area on the contact electrode; injecting a driving body into the driving area by using a nanotip; and bonding the second substrate on which a second electrode is formed to the wall.

23. The method for manufacturing a display device that is driven by an electric field of claim 22, wherein the forming of the contact electrode includes forming a first metal layer that has a first opening on the insulating film, and forming a second metal layer that has a second opening on the first metal layer.