JP2009162927A - Display element and electric equipment using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display element capable of precisely displaying a half tone, and electric equipment using the same. <P>SOLUTION: The display element 10 having display units 10a and 10b comprising upper substrates (first substrates) 2a and 2b, lower substrates (second substrates) 3a and 3b, and conductive liquids 16a and 16b charged in display spaces Sa and Sb formed between the upper substrates 2a and 2b and lower substrates 3a and 3b to move to effective display areas or ineffective display areas therein is constituted by stacking the two display units 10a and 10b such that the effective display areas face each other, the conductive liquids 16a and 16b in the display units 10a and 10b blocking light beams having mutually different wavelengths. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display element that displays information such as images and characters by moving a conductive liquid, and an electric device using the display element.

  In recent years, as represented by an electrowetting type display element, a display element has been developed and put into practical use to display information by utilizing a phenomenon of movement of a conductive liquid by an external electric field.

  Specifically, in the conventional display element as described above, for example, as described in Patent Document 1 below, the first and second electrodes, the first and second substrates, and the distance between these substrates. In addition, the liquid crystal is sealed in a display space formed in the above and is provided with colored droplets as a conductive liquid colored in a predetermined color. In this conventional display element, by applying an electric field to the colored droplets through the first and second electrodes, the shape of the colored droplets is changed to change the display color on the display surface side. It was like that.

In this conventional display element, the first and second electrodes are arranged side by side on the first substrate while being electrically insulated from the colored droplets. A third electrode is provided on the second substrate side so as to face the second electrode. Furthermore, by installing a shade for light shielding above the first electrode, the first electrode side and the second electrode side are set to the non-effective display area side and the effective display area side, respectively. It has been proposed to apply a voltage so that a potential difference is generated between the three electrodes or between the second and third electrodes. In this conventional display element, the colored droplets are moved to the first electrode side or the second electrode side at a higher speed than when the shape of the colored droplets is changed, and the display color on the display surface side is also increased. It was possible to change at high speed.
JP 2004-252444 A

  By the way, in the conventional display element as described above, voltage is applied to these electrodes so that the potential difference generated between the first and third electrodes or between the second and third electrodes is variously changed. The halftone brightness can be controlled by controlling the spread of the colored droplets (conductive liquid).

  However, the conventional display element as described above has a problem that halftone display cannot be performed with high accuracy. Specifically, in the conventional display element, the ratio of the amount of change in the size of the color droplet spread is smaller than the amount of change in the magnitude of the voltage applied to the first to third electrodes. . For this reason, in the conventional display element, even when the magnitude of the voltage applied to the first to third electrodes is changed, the magnitude of the spread of the colored droplets may not be changed. It was difficult to adjust the brightness or display color of the display in multiple stages. As a result, the conventional display element sometimes cannot perform halftone display with high accuracy.

  In view of the above-described problems, an object of the present invention is to provide a display element that can perform halftone display with high accuracy, and an electric device using the display element.

In order to achieve the above object, the display element according to the present invention is configured such that a predetermined display space is formed between the first substrate provided on the display surface side and the first substrate. , The second substrate provided on the non-display surface side of the first substrate, the effective display area and the non-effective display area set for the display space, and the effective inside the display space. A display element comprising a display unit having a conductive liquid movably sealed on the display area side or the ineffective display area side,
N display units (N is an integer of 2 or more) are stacked such that the effective display regions face each other,
In each of the N display units, the conductive liquid is configured to shield light in a predetermined wavelength range.

  In the display element configured as described above, the N display units are stacked such that the effective display areas face each other. In each of the N display units, the conductive liquid is configured to shield light in a predetermined wavelength range. Thus, unlike the conventional example, it is possible to easily adjust the luminance or display color on the display surface side in multiple stages. Therefore, unlike the conventional example, halftone display can be accurately performed.

In the display element, the display unit is provided with a plurality of first electrodes along a predetermined arrangement direction on one side of the first and second substrates,
The effective display area on the other side of the first and second substrates such that a plurality of second electrodes and a plurality of third electrodes alternately and intersect with the plurality of first electrodes. On one side and the other side of the side and the ineffective display area side,
The plurality of first electrodes are used as a plurality of signal electrodes, respectively.
The plurality of second electrodes are used as one of a plurality of reference electrodes and a plurality of scan electrodes, respectively, and
The plurality of third electrodes are used as the other of the plurality of reference electrodes and the plurality of scan electrodes, respectively.
The display unit is connected to the plurality of reference electrodes, and applies a predetermined reference voltage to each of the plurality of reference electrodes.
A signal voltage applying unit that is connected to the plurality of signal electrodes and applies a signal voltage corresponding to information displayed on the display surface side to each of the plurality of signal electrodes;
The conductive voltage is connected to the plurality of scan electrodes and is connected to the plurality of scan electrodes when the reference voltage application unit applies the reference voltage to the plurality of reference electrodes. A non-selection voltage that prevents the liquid from moving inside the display space, and a selection voltage that allows the conductive liquid to move inside the display space according to the signal voltage. It is preferable to include a scanning voltage application unit that applies one voltage.

  In this case, a matrix driving display element having excellent display quality can be formed.

Further, in the display element, a plurality of pixels are provided in the N display unit units,
Each pixel region of the plurality of pixels may be provided in a unit of intersection of the signal electrode and the scan electrode, and the display space may be partitioned by a partition wall in each pixel region.

  In this case, the display color on the display surface side can be changed in units of pixels by moving the conductive liquid in each of the plurality of pixels on the display surface side.

  In the display element, the plurality of pixels may be provided in accordance with a plurality of colors capable of full color display on the display surface side.

  In this case, a display element capable of displaying a color image can be configured.

  In the display element, it is preferable that one reference voltage application unit and one scan voltage application unit are shared in the N display units.

  In this case, in the N display units, the conductive liquid can be easily and synchronously moved, and the moire phenomenon can be performed while facilitating each voltage application process in the reference voltage application unit and the scanning voltage application unit. Can be surely prevented.

  In the display element, in each of the N display units, the wavelength range of the light shielded by the conductive liquid may be different by changing the colorant used for the conductive liquid. .

  In this case, in each display unit, the light shielding area by the conductive liquid can be reliably made different.

  In the display element, the display unit is preferably provided with a color filter portion of a predetermined color on the effective display area side.

  In this case, the halftone reproduction (display) range can be expanded more easily.

  In the display element, in the N display units, the conductive liquid of one display unit may be colored black.

  In this case, the one display unit can function as a shutter, and black display can be appropriately performed.

The electrical device of the present invention is an electrical device including a display unit that displays information including characters and images,
Any one of the display elements described above is used for the display portion.

  In the electrical device configured as described above, a display element capable of accurately displaying halftones is used for the display unit. Therefore, the high-performance electrical device having a display unit having excellent display quality Can be configured easily.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the display element which can perform a halftone display accurately, and an electric equipment using the same.

  Hereinafter, preferred embodiments of a display element and an electric device of the present invention will be described with reference to the drawings. In the following description, a case where the present invention is applied to an image display apparatus including a display unit capable of displaying a color image display will be described as an example. Moreover, the dimension of the structural member in each figure does not faithfully represent the actual dimension of the structural member, the dimensional ratio of each structural member, or the like.

[First Embodiment]
FIG. 1 is a plan view for explaining a display element and an image display apparatus according to a first embodiment of the present invention. In FIG. 1, in the image display apparatus 1 of the present embodiment, a display unit using the display element 10 of the present invention is provided, and a rectangular display surface is configured in the display unit. Further, in the display element 10, two display units 10a and 10b are stacked in this order in a direction perpendicular to the paper surface of FIG. 1, and are provided in units of display units 10a and 10b in which one pixel is stacked. It is like that. Each display unit 10a, 10b includes an upper substrate 2a, 2b and a lower substrate 3a, 3b arranged to overlap each other in a direction perpendicular to the paper surface of FIG. An effective display area of the display surface is formed by overlapping portions with the lower substrates 3a and 3b (details will be described later). The display units 10a and 10b are different only in the configuration of a light shielding layer, a color filter layer, and a conductive liquid, which will be described later.

  In the display units 10a and 10b, the plurality of signal electrodes 4a and 4b are provided in stripes along the X direction at a predetermined interval from each other. In the display units 10a and 10b, a plurality of reference electrodes 5a and 5b and a plurality of scanning electrodes 6a and 6b are provided alternately in a stripe pattern along the Y direction. The plurality of signal electrodes 4a, 4b, the plurality of reference electrodes 5a, 5b, and the plurality of scanning electrodes 6a, 6b are provided so as to intersect with each other. In each display unit 10a, 10b, the signal electrodes 4a, A plurality of pixel regions are set in units of intersections between 4b and the scan electrodes 6a and 6b.

  In addition, the plurality of signal electrodes 4a and 4b, the plurality of reference electrodes 5a and 5b, and the plurality of scanning electrodes 6a and 6b are independently of each other a high voltage as a first voltage and a second voltage as a second voltage. A voltage within a predetermined voltage range between the low voltage and the low voltage can be applied (details will be described later).

  Further, in the display units 10a and 10b, as will be described in detail later, each of the plurality of pixel regions is partitioned by a partition wall, and in the display element 10, the plurality of pixels can be displayed in full color on the display surface side. Each is provided according to a plurality of possible colors. Specifically, the display element 10 includes, for example, units of display units 10a and 10b in which pixels of each color of RGB are stacked. Then, in the display units 10a and 10b, the display element 10 has a display surface of a corresponding pixel by moving a conductive liquid described later by an electrowetting phenomenon for each of a plurality of pixel regions provided in a matrix. The display color on the side is changed.

  In addition, one end of each of the plurality of signal electrodes 4a and 4b, the plurality of reference electrodes 5a and 5b, and the plurality of scanning electrodes 6a and 6b is drawn outside the effective display area of the display surface, and the terminal portions 4a1 and 4b1. 5a1, 5b1, and 6a1, 6b1 are formed.

  Signal drivers 7a and 7b are connected to the terminal portions 4a1 and 4b1 of the plurality of signal electrodes 4a and 4b via wirings 7a1 and 7b1, respectively. Each signal driver 7a, 7b constitutes a signal voltage application unit. When the image display device 1 displays information including characters and images on the display surface, the signal drivers 7a, 7b are connected to the plurality of signal electrodes 4a, 4b. Thus, the signal voltage Vg corresponding to the information is applied.

  Reference drivers 8a and 8b are connected to the terminal portions 5a1 and 5b1 of the plurality of reference electrodes 5a and 5b via wirings 8a1 and 8b1, respectively. Each of the reference drivers 8a and 8b constitutes a reference voltage application unit. When the image display device 1 displays information including characters and images on the display surface, each of the reference drivers 5a and 8b has a plurality of reference electrodes 5a and 5b. Thus, the predetermined reference voltage Vs is always applied.

  The scanning drivers 9a and 9b are connected to the terminal portions 6a1 and 6b1 of the plurality of scanning electrodes 6a and 6b via the wirings 9a1 and 9b1, respectively. Each of the scanning drivers 9a and 9b constitutes a scanning voltage application unit. When the image display device 1 displays information including characters and images on the display surface, the scanning drivers 9a and 9b correspond to the plurality of scanning electrodes 6a and 6b. Thus, the scanning voltage Vd is applied.

  In the scanning drivers 9a and 9b, when the reference drivers 8a and 8b apply the reference voltage Vs to the plurality of reference electrodes 5a and 5b, One voltage of a non-selection voltage that prevents the conductive liquid from moving and a selection voltage that allows the conductive liquid to move in response to the signal voltage Vg is applied as the scanning voltage Vd. . In the image display device 1, the scanning drivers 9a and 9b sequentially apply a selection voltage to the scanning electrodes 6a and 6b from the left side to the right side in FIG. (Details will be described later).

  The signal drivers 7a and 7b, the reference drivers 8a and 8b, and the scanning drivers 9a and 9b include a DC power supply or an AC power supply, and supply corresponding signal voltage Vg, reference voltage Vs, and scanning voltage Vd. It is supposed to be.

  The reference drivers 8a and 8b are configured to switch the polarity of the reference voltage Vs every predetermined time (for example, one frame). Further, the scanning drivers 9a and 9b are configured to switch each polarity of the scanning voltage Vd in response to switching of the polarity of the reference voltage Vs. As described above, the polarities of the reference voltage Vs and the scanning voltage Vd are switched every predetermined time, so that the voltages of the same polarity are always applied to the reference electrodes 5a and 5b and the scanning electrodes 6a and 6b. Thus, it is possible to prevent the charge from being localized in the reference electrodes 5a and 5b and the scanning electrodes 6a and 6b. Furthermore, it is possible to prevent adverse effects of display defects (afterimage phenomenon) and reliability (lifetime reduction) due to charge localization.

  Here, the pixel structure of the display element 10 will be specifically described with reference to FIGS.

  2 (a) and 2 (b) are enlarged views showing the configuration of the main part on the upper substrate side in the first and second display units shown in FIG. 1 when viewed from the display surface side. It is a top view. FIG. 3 is an enlarged plan view showing a configuration of a main part on the lower substrate side in each of the display units of the first layer and the second layer when viewed from the non-display surface side, and FIG. 4 is an essential plan view of the display element. It is sectional drawing which shows a part structure. 2 and 3, for simplification of the drawings, of the plurality of pixels provided on the display surface, twelve pixels disposed at the upper left end portion of FIG. 1 are illustrated. .

  2 to 4, the display units 10a and 10b are provided on the upper substrates 2a and 2b as the first substrates provided on the display surface side, and on the back side (non-display surface side) of the upper substrates 2a and 2b. The lower substrate 3a, 3b as a second substrate provided is provided. Further, in the display units 10a and 10b, the upper substrates 2a and 2b and the lower substrates 3a and 3b are arranged at a predetermined distance from each other, so that a predetermined distance is provided between the upper substrates 2a and 3b and the lower substrates 3a and 3b. Display spaces Sa and Sb are formed. In addition, in the display spaces Sa and Sb, the conductive liquids 16a and 16b and insulating oils 17a and 17b that do not mix with the conductive liquids 16a and 16b are contained in the display spaces Sa and Sb. The conductive liquids 16a and 16b can be moved to the effective display area P1 side or the non-effective display area P2 side, which will be described later, so as to be movable in the X direction (left and right direction in FIG. 4).

  For the conductive liquids 16a and 16b, for example, an aqueous solution containing water as a solvent and a predetermined electrolyte as a solute is used. Specifically, for example, an aqueous solution of 1 mmol / L potassium chloride (KCl) is used for the conductive liquids 16a and 16b. Further, these conductive liquids 16a and 16b are configured such that the wavelength ranges of the light shielded by the conductive liquids 16a and 16b are different from each other. In other words, the conductive liquids 16a and 16b are configured such that the wavelength ranges (transmission wavelength ranges) of light allowed to pass by the conductive liquids 16a and 16b are different from each other.

  Specifically, in the red pixel illustrated in FIG. 4, the conductive liquid 16a of the display unit 10a in the first layer (upper side) used is colored red by a colorant such as a pigment or a dye. Has been. On the other hand, as the conductive liquid 16b of the display unit 10b of the second layer (lower side), the one colored black by the colorant is used. In the green and blue pixels, the conductive liquid 16a of the display unit 10a is colored green and blue with the colorant, and the conductive liquid 16b of the display unit 10b is colored. The one colored black by the agent is used.

  As described above, the conductive liquid 16a is colored in any of RGB colors, and allows light in the wavelength region of the colored color to pass through. On the other hand, since the conductive liquid 16b is colored in black, the conductive liquid 16b functions as a shutter that allows or blocks light transmission in each pixel. That is, in each pixel of the display element 10, as will be described in detail later, the conductive liquid 16 b is disposed inside the display space Sb on the reference electrode 5 side (effective display region P 1 side) or the scan electrode 6 side (non-effective display region). The display color is changed to either black or RGB by sliding to (P2 side).

  The oils 17a and 17b include, for example, nonpolar and colorless and transparent oils selected from one or more selected from side chain higher alcohols, side chain higher fatty acids, alkane hydrocarbons, silicone oils, and matching oils. Is used. The oils 17a and 17b move inside the display spaces Sa and Sb as the conductive liquids 16a and 167b slide.

  For the upper substrates 2a and 2b, a transparent glass material such as a non-alkali glass substrate or a transparent transparent sheet material such as a transparent synthetic resin such as an acrylic resin is used. Further, the light shielding layer 11 and the water repellent film 12a are sequentially formed on the surface of the upper substrate 2a on the non-display surface side, and the signal electrode 4a as the first electrode is provided on the water repellent film 12a. It has been. Further, the color filter layer Cf and the water repellent film 12b are sequentially formed on the surface of the upper substrate 2b on the non-display surface side, and further, the signal electrode 4b as the first electrode is formed on the water repellent film 12b. Is provided.

  The lower substrates 3a and 3b are made of a transparent transparent sheet material such as a transparent glass material such as an alkali-free glass substrate or a transparent synthetic resin such as an acrylic resin, like the upper substrates 2a and 2b. Yes. Further, the reference electrodes 5a and 5b as the second electrodes and the scanning electrodes 6a and 6b as the third electrodes are provided on the surface on the display surface side of the lower substrates 3a and 3b. Dielectric layers 13a and 13b are formed so as to cover the reference electrodes 5a and 5b and the scanning electrodes 6a and 6b. In addition, ribs 14y1 and 14x1 are provided on the surface of the dielectric layer 13a on the display surface side so as to be parallel to the Y direction and the X direction, respectively. Similarly, ribs 14y2 and 14x2 are provided on the surface of the dielectric layer 13b on the display surface side so as to be parallel to the Y direction and the X direction, respectively.

  The lower substrate 3a is provided with a water repellent film 15a so as to cover the dielectric layer 13a and the ribs 14x1 and 14y1, and the lower substrate 3b is provided so as to cover the dielectric layer 13b, the ribs 14x2 and 14y2. A water repellent film 15b is provided.

  Further, a backlight 18 that emits white illumination light, for example, is integrally assembled on the back side (non-display surface side) of the lower substrate 3b, and the transmissive display element 10 is configured. Thus, since the backlight 18 is used, the display element 10 according to the present embodiment can perform an appropriate display operation even when the outside light is insufficient or at night. Further, in the present embodiment, it is possible to easily configure the high-luminance display element 10 that has a large dimming range and can easily perform high-precision gradation control.

  Further, as shown in FIG. 2A, the light shielding layer 11 on the display unit 10a side is provided with a transparent portion 11t using a transparent resin and a black matrix portion 11s as a light shielding film. Further, the color filter layer Cf on the display unit 10b side has red (R), green (G), and blue (B) color filter portions Cfr and Cfg as shown in FIG. 2B. , And Cfb and a black matrix portion Cfs as a light shielding film are provided, and constitute pixels of each color of RGB. That is, in the color filter layer Cf, as illustrated in FIG. 2B, RGB color filter portions Cfr, Cfg, and Cfb are sequentially provided along the X direction, and four color filter portions Cfr, Cfg, Cfb is provided along the Y direction, and a total of 12 pixels, 3 and 4 in the X direction and Y direction, respectively, are arranged in units of the display units 10a and 10b.

  Specifically, in the display unit 10a, as shown in FIG. 2A, in each pixel region P, a transparent portion 11t is provided at a position corresponding to the effective display region P1 of the pixel, and the ineffective display region P2 is provided. A black matrix portion 11s is provided at a corresponding location. That is, in the display unit 10a, an ineffective display region P2 (non-opening portion) is set for the display space Sa by the black matrix portion (light-shielding film) 11s, and an opening portion formed in the black matrix portion 11s ( That is, the effective display area P1 is set by the transparent portion 11t).

  On the other hand, in the display unit 10b, as shown in FIG. 2B, in each pixel region P, any one of RGB color filter portions Cfr, Cfg, and Cfb is provided at a location corresponding to the effective display region P1 of the pixel. In addition, a black matrix portion Cfs is provided at a location corresponding to the ineffective display area P2. That is, in the display unit 10b, an ineffective display region P2 (non-opening portion) is set for the display space Sb by the black matrix portion (light-shielding film) Cfs, and the opening portion formed in the black matrix portion Cfs ( That is, the effective display area P1 is set by any one of the color filter portions Cfr, Cfg, and Cfb). The color filter sections Cfr, Cfg, and Cfb each have predetermined color filter characteristics, that is, those having a wavelength range (transmission wavelength range) of light that is allowed to pass by the color filter sections Cfr, Cfg, and Cfb. It has been.

  Further, in the display element 10, the display units 10 a and 10 b are stacked so that the effective display areas P <b> 1 face each other in a direction perpendicular to the display surface of the image display device 1. That is, in the display element 10, in each of the RGB pixels, the transparent portion 11t on the display unit 10a side and any of the color filter portions Cfr, Cfg, and Cfb on the display unit 10b side overlap each other in the vertical direction. As is provided.

  In the display element 10, the transparent areas 11t and the color filter sections Cfr, Cfg, Cfb are selected to have the same or slightly larger values than the effective display area P1. On the other hand, the area of each of the black matrix portions 11s and Cf is selected to be the same or slightly smaller than the area of the ineffective display area P2. In FIG. 2, in order to clarify the boundary portion between adjacent pixels, the boundary line between the two black matrix portions Cfs or 11s corresponding to the adjacent pixels is indicated by a dotted line. 11 or the color filter layer Cf, there is no boundary line between the black matrix portions Cfs or 11s.

  Further, in the display unit 10a, the display space Sa is divided into pixel regions P by the ribs 14x1 and 14y1 as the partition walls. That is, in the display unit 10a, the display space Sa of each pixel is partitioned by two ribs 14x1 facing each other and two ribs 14y1 facing each other, as illustrated in FIG. In other words, the dimension in the Y direction of the pixel region P (FIG. 2) is defined by the two ribs 14x1 facing each other, and the dimension in the X direction of the pixel region P is defined by the two ribs 14y1 facing each other. .

  Similarly, in the display unit 10b, the display space Sb is divided into pixel regions P by the ribs 14x2 and 14y2 as the partition walls. That is, in the display unit 10b, the display space Sb of each pixel is partitioned by two ribs 14x2 facing each other and two ribs 14y2 facing each other, as illustrated in FIG. In other words, the dimension in the Y direction of the pixel region P (FIG. 2) is defined by the two ribs 14x2 facing each other, and the dimension in the X direction of the pixel region P is defined by the two ribs 14y2 facing each other. .

  Further, in the display unit 10a, the ribs 14x1 and 14y1 prevent the conductive liquid 16a from flowing into the display space Sa of the adjacent pixel region P. Similarly, in the display unit 10b, the ribs 14x2 and 14y2 prevent the conductive liquid 16b from flowing into the display space Sb of the adjacent pixel region P. That is, for example, a photo-curing resin is used for the ribs 14x1, 14y1, 14x2, and 14y2, and in these ribs 14x1, 14y1, 14x2, and 14y2, the conductive liquids 16a and 16b corresponding to each other between adjacent pixels are used. The protruding height from the dielectric layers 13a and 13b is determined so that the inflow and outflow are prevented.

  In addition to the above description, instead of the ribs 14x1, 14y1, 14x2, and 14y2, for example, ribs configured in a frame shape on the lower substrates 3a and 3b may be provided for each pixel. Further, the end portions of the ribs configured in the frame shape may be brought into close contact with the upper substrates 2a and 2b so that the adjacent pixel regions P are hermetically separated. Thus, when the tip of the rib is brought into close contact with the upper substrate 2a, 2b, the signal electrode 4a is provided inside the display spaces Sa, Sb by providing the signal electrodes 4a, 4b so as to penetrate the rib. 4b may be installed.

  For the water-repellent films 12a, 12b, 15a and 15b, transparent synthetic resin, preferably a fluorine-based resin having a thickness of 60 nm, for example, which becomes a hydrophilic layer with respect to the conductive liquids 16a and 16b corresponding to voltage application is used. Yes. Thereby, in the display units 10a and 10b, wettability (contact angle) between the upper substrates 2a and 2b and the conductive liquids 16a and 16b on the respective surface sides of the lower substrates 3a and 3b on the display spaces Sa and Sb side. ) Can be greatly changed, and the moving speed of the conductive liquids 16a and 16b can be increased. The dielectric layers 13a and 13b are made of a transparent dielectric film containing, for example, parylene, silicon nitride, hafnium oxide, zinc oxide, titanium dioxide, or aluminum oxide.

Transparent electrode materials such as indium oxide (ITO), tin oxide (SnO ₂ ), or zinc oxide (AZO, GZO, or IZO) are used for the reference electrodes 5a and 5b and the scan electrodes 6a and 6b. ing. Each of these reference electrodes 5a and 5b and each of the scanning electrodes 6a and 6b is formed in a strip shape on the lower substrates 3a and 3b with a thickness of 100 nm, for example, by a known film forming method such as sputtering.

  For the signal electrodes 4a and 4b, linear wirings arranged so as to be parallel to the X direction are used. Further, the signal electrodes 4a and 4b are installed on the water-repellent films 12a and 12b so as to pass through substantially the center of each pixel region P in the Y direction, and are inserted through the conductive liquids 16a and 16b. It is configured to directly contact the conductive liquids 16a and 16b. Thereby, in the display units 10a and 10b, the responsiveness of the conductive liquids 16a and 16b during the display operation is improved.

  The signal electrodes 4a and 4b are made of a material that is electrochemically inactive with respect to the conductive liquids 16a and 16b, and the signal voltage Vg (for example, 40 V) is applied to the signal electrodes 4a and 4b. Even when is applied, an electrochemical reaction with the conductive liquids 16a and 16b is avoided as much as possible. Thereby, generation | occurrence | production of the electrolysis of signal electrode 4a, 4b can be prevented, and the reliability and lifetime of the display element 10 can be improved.

  Specifically, for the signal electrodes 4a and 4b, an electrode material containing at least one of gold, silver, copper, platinum, and palladium is used, and the upper substrates 2a and 2b side are formed by screen printing or the like. Is provided. Further, the shape of the signal electrodes 4a and 4b is determined using the transmittance of the reference electrodes 5a and 5b provided below the effective display area P1 of the pixel.

  Here, the display operation of the image display apparatus 1 of the present embodiment configured as described above will be specifically described with reference to FIGS.

  FIG. 5 is a diagram for explaining an operation example in the display unit. FIG. 6 is a cross-sectional view illustrating an operation example of the display element, and FIG. 7 is a cross-sectional view illustrating another operation example of the display element.

  First, a basic operation (scanning operation) of each of the display units 10a and 10b will be described with reference to FIG. In the following description, since the scanning operations of the display units 10a and 10b are performed based on the same operation principle, the scanning operation of the display unit 10a will be described as an example (the same applies to the display unit 10c described later). In FIG. 5, the effective display area side and the ineffective display area side are abbreviated as the effective side and the ineffective side, respectively.

  In FIG. 5, the reference driver 8a always applies the High voltage (first voltage) as the reference voltage Vs to all the reference electrodes 5a. Further, the scan driver 9a sequentially applies the selection voltage as the scan voltage Vd to the scan electrode 6a in a predetermined scan direction from the left side to the right side in FIG. Specifically, the scanning driver 9a performs a scanning operation to sequentially apply a Low voltage (second voltage) as a selection voltage to the scanning electrode 6a to form a selection line. In this selection line, the signal driver 7a applies a High voltage or a Low voltage as the signal voltage Vg to the corresponding signal electrode 4a in accordance with an image input signal from the outside. Thereby, in each pixel of the selection line, the conductive liquid 16a is moved to the effective display area P1 side or the non-effective display area P2 side, and the display color and gradation on the display surface side are changed (details will be described later). .)

  Further, the scan driver 9a applies the High voltage as the non-selection voltage to all the remaining scan electrodes 6a to which the Low voltage is not applied, thereby forming a non-selection line. Thereby, in each pixel of the non-selected line, the conductive liquid 16a is stopped on the effective display area P1 side or the non-effective display area P2 side.

  When the display operation as described above is performed, combinations of voltages applied to the reference electrode 5a, the scan electrode 6a, and the signal electrode 4a are as shown in Table 1. Further, as shown in Table 1, the behavior of the conductive liquid 16a depends on the applied voltage. In Table 1, the High voltage and the Low voltage are abbreviated as “H” and “L”, respectively (the same applies to Table 2 described later).

<Operation on selected line>
In the selection line, for example, when a high voltage is applied to the signal electrode 4a, a high voltage is applied between the reference electrode 5a and the signal electrode 4a. There is no potential difference between the electrode 4a. On the other hand, between the signal electrode 4a and the scan electrode 6a, a low voltage is applied to the scan electrode 6a, so that a potential difference is generated. For this reason, the conductive liquid 16a moves inside the display space Sa toward the scanning electrode 6a where a potential difference is generated with respect to the signal electrode 4a. As a result, as illustrated in FIG. 4, the conductive liquid 16a moves to the ineffective display area P2 side, and moves the oil 17a to the reference electrode 5a side.

  On the other hand, when a low voltage is applied to the signal electrode 4a in the selected line, a potential difference is generated between the reference electrode 5a and the signal electrode 4a, and between the signal electrode 4a and the scanning electrode 6a. No potential difference has occurred. Accordingly, the conductive liquid 16a moves in the display space Sa toward the reference electrode 5a side where a potential difference is generated with respect to the signal electrode 4a. As a result, the conductive liquid 16a moves to the effective display area P1 side, contrary to FIG. 4, and moves the oil 17a to the scan electrode 6a side.

<Operation on unselected lines>
In the non-selected line, for example, when a high voltage is applied to the signal electrode 4a, all of the signal electrode 4a, the reference electrode 5a, and the scanning electrode 6a become a high voltage, and there is a potential difference between these electrodes. Has not occurred. Therefore, the conductive liquid 16a is maintained in a stationary state without moving from the current position, that is, the reference electrode 5a side or the scan electrode 6a side.

  Similarly, even when a low voltage is applied to the signal electrode 4a in the non-selected line, the conductive liquid 16a is maintained stationary at the current position. That is, since the High voltage is applied to both the reference electrode 5a and the scan electrode 6a, the potential difference between the reference electrode 5a and the signal electrode 4a and the potential difference between the scan electrode 6a and the signal electrode 4a are as follows. This is because the same potential difference occurs in both cases.

  Further, the combinations of voltages applied to the reference electrode 5a, the scan electrode 6a, and the signal electrode 4a are not limited to Table 1, but may be those shown in Table 2.

  That is, a low voltage (second voltage) is always applied to the reference electrode 5a as the reference voltage Vs from the reference driver 8a. A scanning driver 9a applies a high voltage (first voltage) one by one sequentially from the left side of FIG. 1 as the selection voltage to the scanning electrode 6a so as to perform a scanning operation to select lines. In addition, the scan driver 9a applies the Low voltage as the non-selection voltage to all the remaining scan electrodes 6a to which the High voltage is not applied to form a non-selection line. A high voltage or a low voltage is applied to the signal electrode 4a as the signal voltage Vg according to an image input signal from the outside by the signal driver 7a.

<Operation on selected line>
In the selection line, for example, when a low voltage is applied to the signal electrode 4a, a low voltage is applied between the reference electrode 5a and the signal electrode 4a. There is no potential difference between the electrode 4a. On the other hand, a high voltage is applied to the scanning electrode 6a between the signal electrode 4a and the scanning electrode 6a, and therefore a potential difference is generated. Accordingly, the conductive liquid 16a moves in the display space Sa toward the scanning electrode 6a where a potential difference is generated with respect to the signal electrode 4a. As a result, as illustrated in FIG. 4, the conductive liquid 16a moves to the ineffective display area P2 side, and moves the oil 17a to the reference electrode 5 side.

  On the other hand, when a high voltage is applied to the signal electrode 4a in the selection line, a potential difference is generated between the reference electrode 5a and the signal electrode 4a, and between the signal electrode 4a and the scanning electrode 6a. No potential difference has occurred. Accordingly, the conductive liquid 16a moves in the display space Sa toward the reference electrode 5a side where a potential difference is generated with respect to the signal electrode 4a. As a result, the conductive liquid 16a moves to the effective display area P1 side, contrary to FIG. 4, and moves the oil 17a to the scan electrode 6a side.

<Operation on unselected lines>
In the non-selected line, for example, when a low voltage is applied to the signal electrode 4a, the signal electrode 4, the reference electrode 5a, and the scanning electrode 6a all have a low voltage, and there is a potential difference between these electrodes. Has not occurred. Therefore, the conductive liquid 16a is maintained in a stationary state without moving from the current position, that is, the reference electrode 5a side or the scan electrode 6a side.

  Similarly, even when the High voltage is applied to the signal electrode 4a in the non-selected line, the conductive liquid 16a is maintained in a stationary state at the current position. That is, since the Low voltage is applied to both the reference electrode 5a and the scan electrode 6a, the potential difference between the reference electrode 5a and the signal electrode 4a and the potential difference between the scan electrode 6a and the signal electrode 4a are as follows. This is because the same potential difference occurs in both cases.

  Further, in the image display device 1 of the present embodiment, in addition to the combinations of applied voltages shown in Tables 1 and 2, the applied voltage to the signal electrode 4a is not limited to the binary of the High voltage or the Low voltage, but these The voltage between the high voltage and the low voltage can be changed in accordance with information displayed on the display surface side. That is, the image display device 1 can perform gradation display by controlling the signal voltage Vg. Thereby, the display element 10 excellent in display performance can be configured.

  Next, the gradation display operation in the present embodiment will be specifically described with reference to FIGS. 4, 6, and 7. In the following description, an operation with a red pixel will be described as an example. In the following description, for the sake of simplicity of explanation, a case where the transmission wavelength region of the conductive liquid 16a and the transmission wavelength region of the color filter portion Cfr are the same will be described as an example.

  As shown in FIG. 4, the conductive liquid 16a of the display unit 10a is moved to the scanning electrode 6a (ineffective display area P2) side, and the conductive liquid 16b of the display unit 10b is moved to the reference electrode 5b (effective display area P1) side. The illumination light from the backlight 18 is blocked by the conductive liquid 16b colored black. As a result, the illumination light is prevented from reaching the color filter portion Cfr, and the display color on the display surface side of the red pixel is in a black display state by the conductive liquid 16b.

  Further, as shown in FIG. 6, when the conductive liquid 16a of the display unit 10a and the conductive liquid 16b of the display unit 10b are moved to the scanning electrodes 6a and 6b (ineffective display area P2) side, the backlight 18 The illumination light from the backlight 18 is allowed to reach the color filter portion Cfr. The illumination light sequentially passes through the color filter portion Cfr and the transparent portion 11t and is emitted to the outside. As a result, the display color on the display surface side of the red pixel is in a red display state by the color filter portion Cfr.

  Further, as shown in FIG. 7, the conductive liquid 16a of the display unit 10a is moved to the reference electrode 5a (effective display area P1) side, and the conductive liquid 16b of the display unit 10b is scanned electrode 6b (non-effective display area P2). When moved to the) side, the illumination light from the backlight 18 passes through the color filter portion Cfr and then passes through the inside of the conductive liquid 16a colored in red. And this illumination light passes the transparent part 11t, and is radiate | emitted outside. As a result, the display color on the display surface side of the red pixel is in a red display state by the color filter portion Cfr and the conductive liquid 16a.

  Further, in the case shown in FIG. 7, the display color on the display surface side of the red pixel is reduced in luminance by the amount that has passed through the inside of the conductive liquid 16a, compared to the case shown in FIG. The display becomes dark red. That is, in the case shown in FIG. 7, a part of the illumination light is absorbed by the conductive liquid 16a, and the amount of red light emitted to the outside is lower than that shown in FIG.

  As described above, in the red pixel, the gradation display of the three gradations shown in FIGS. 4, 6, and 7 is performed. Further, in the image display device 1, as shown in FIG. 6, the conductive liquids 16a and 16b move to the ineffective display region P2 side in all three adjacent RGB pixels, and complete RGB color display is performed. Is performed, the red light, the green light, and the blue light from the RGB pixels are mixed with the white light, and white display is performed.

  In addition to the above description, when the transmission wavelength range of the conductive liquid 16a is different from the transmission wavelength range of the color filter portion Cfr, it is emitted to the outside as compared with the case where these transmission wavelength ranges are the same. The brightness and display color of the emitted light can be slightly changed (the same applies to the following embodiments).

  In the display element 10 of the present embodiment configured as described above, two display units 10a and 10b are stacked so that the effective display areas P1 face each other. In each of the two display units 10a and 10b, the conductive liquids 16a and 16b are configured so that the wavelength ranges of the light shielded by the conductive liquids 16a and 16b are different from each other. As a result, in the display element 10 of the present embodiment, unlike the conventional example, the display color on the display surface side is adjusted to three levels of gradation as shown in FIGS. 4, 6, and 7. Can be easily performed. Therefore, unlike the conventional example, the display element 10 of the present embodiment can perform halftone display with high accuracy.

  Further, in the image display device (electric device) 1 of the present embodiment, since the display element 10 is used for the display unit, a high-performance image display device including a display unit having excellent display quality is easily configured. can do.

  In the display element 10 of the present embodiment, in each display unit 10a, 10b, a plurality of scanning electrodes (second electrodes) 5a, 5b and a plurality of reference electrodes (third electrodes) 6a, 6b are alternately arranged. In addition, it is provided on the lower substrate (second substrate) 3a, 3b side so as to intersect with the plurality of signal electrodes 4a, 4b. Further, signal drivers (signal voltage application units) 7a and 7b, scan drivers (scan voltage application units) 8a and 8b, and reference drivers (reference voltage application units) 9a and 9b are signal electrodes 4a and 4b, and scan electrodes 5a and 5b. A signal voltage, a scanning voltage (selection voltage or non-selection voltage), and a reference voltage are applied to the reference electrodes 6a and 6b. As a result, in the present embodiment, it is possible to configure a matrix driving type display element having excellent display quality.

[Second Embodiment]
FIG. 8 is a plan view for explaining a display element and an image display device according to the second embodiment of the present invention, and FIG. In the figure, the main difference between this embodiment and the first embodiment is that one display voltage application unit and one scanning voltage application unit are shared in two display units. In addition, about the element which is common in the said 1st Embodiment, the same code | symbol is attached | subjected and the duplicate description is abbreviate | omitted.

  That is, as shown in FIG. 8, in the image display device 1 of the present embodiment, one reference driver (reference voltage application unit) 8 is connected to the terminal portions 5a1 and 5b1 of the reference electrodes 5a and 5b of the display units 10a and 10b. The wirings 8a1 and 8b1 are connected to each other. One scanning driver (scanning voltage applying unit) 9 is connected to the terminal portions 6a1 and 6b1 of the scanning electrodes 6a and 6b of the display units 10a and 10b via wirings 9a1 and 9b1. In the image display apparatus 1 of the present embodiment, one reference driver 8 and one scan driver 9 are shared with the display units 10a and 10b in units of pixels in which the above scanning operations are performed simultaneously. That is, the reference driver 8 simultaneously applies the reference voltage to the reference electrodes 5a and 5b of the display units 10a and 10b, and the scan driver 9 applies to the scan electrodes 6a and 6b of the display units 10a and 10b. The scanning voltage is applied simultaneously.

  In the present embodiment, as shown in FIG. 9, in the display unit 10b of the second layer, the reference electrode 5b and the scanning electrode 6b are provided on the upper substrate 2b side, and the signal electrode 4b is provided on the lower substrate 3b side. . Specifically, in the upper substrate 2b, the reference electrode 5b and the scanning electrode 6b are arranged in parallel on the color filter layer Cf, and the dielectric layer 13b is formed so as to cover the reference electrode 5b and the scanning electrode 6b. ing. Further, on the upper substrate 2b side, ribs 14x2, 14y2 and a water repellent film 15b are sequentially provided on the dielectric layer 13b. On the other hand, on the lower substrate 3b side, a water repellent film 12b and a signal electrode 4b are sequentially installed on the surface on the display space Sb side.

  As described above, in the second embodiment, in the second layer display unit 10b, the reference electrode 5b and the scanning electrode 6b are provided on the upper substrate 2b side, whereby the first layer display unit 10a has the lower substrate 3a side. The reference electrode 5b and the scan electrode 6b can be disposed close to the provided reference electrode 5b and the scan electrode 6b. As a result, the wiring (connection) dimensions of the wirings 8a1, 8b1 and 9a1, 9b1 to the reference driver 8 and the scanning driver 9 can be reduced, and the wiring (connection) work can be simplified. .

  Here, the gradation display operation in the present embodiment configured as described above will be described in detail with reference to FIGS. In the following description, an operation with a red pixel will be described as an example. In the following description, for the sake of simplicity of explanation, a case where the transmission wavelength region of the conductive liquid 16a and the transmission wavelength region of the color filter portion Cfr are the same will be described as an example.

  FIG. 10 is a cross-sectional view for explaining an operation example of the display element shown in FIG. 8, and FIG. 11 is a cross-sectional view for explaining another operation example of the display element shown in FIG.

  As shown in FIG. 9, the conductive liquid 16a of the display unit 10a is moved to the scanning electrode 6a (ineffective display area P2) side, and the conductive liquid 16b of the display unit 10b is moved to the reference electrode 5b (effective display area P1) side. The illumination light from the backlight 18 is blocked by the conductive liquid 16b colored black. As a result, the illumination light is prevented from reaching the color filter portion Cfr, and the display color on the display surface side of the red pixel is in a black display state by the conductive liquid 16b.

  Further, as shown in FIG. 10, when the conductive liquid 16a of the display unit 10a and the conductive liquid 16b of the display unit 10b are moved to the scan electrodes 6a and 6b (ineffective display area P2) side, the backlight 18 The illumination light from the backlight 18 is allowed to reach the color filter portion Cfr. The illumination light sequentially passes through the color filter portion Cfr and the transparent portion 11t and is emitted to the outside. As a result, the display color on the display surface side of the red pixel is in a red display state by the color filter portion Cfr.

  As shown in FIG. 11, the conductive liquid 16a of the display unit 10a is moved to the reference electrode 5a (effective display area P1) side, and the conductive liquid 16b of the display unit 10b is scanned electrode 6b (non-effective display area P2). When moved to the) side, the illumination light from the backlight 18 passes through the color filter portion Cfr and then passes through the inside of the conductive liquid 16a colored in red. And this illumination light passes the transparent part 11t, and is radiate | emitted outside. As a result, the display color on the display surface side of the red pixel is in a red display state by the color filter portion Cfr and the conductive liquid 16a.

  Further, in the case shown in FIG. 11, the display color on the display surface side of the red pixel is reduced in luminance by the amount that has passed through the inside of the conductive liquid 16a, compared to the case shown in FIG. The display becomes dark red. That is, in the case shown in FIG. 11, a part of the illumination light is absorbed by the conductive liquid 16a, and the amount of red light emitted to the outside is reduced as compared with the case shown in FIG.

  As described above, in the red pixel, the gradation display of the three gradations shown in FIGS. 9, 10, and 11 is performed. Further, in the image display device 1, as shown in FIG. 10, the conductive liquids 16a and 16b move to the ineffective display region P2 side in all three adjacent RGB pixels, and complete RGB color display is performed. Is performed, the red light, the green light, and the blue light from the RGB pixels are mixed with the white light, and white display is performed.

  With the above configuration, the present embodiment can achieve the same operations and effects as the first embodiment. In the present embodiment, since the two display units 10a and 10b share one reference driver (reference voltage application unit) 8 and one scan driver (scan voltage application unit) 9, there are two display units 10a and 10b. In the display units 10a and 10b, the conductive liquids 16a and 16b can be easily moved in synchronism, and each voltage application process in the reference driver 8 and the scan driver 9 is facilitated, and the occurrence of a moiré phenomenon occurs. Can be surely prevented.

  In addition to the above description, a display element using three or more layers of display units may share one reference voltage application unit and one scanning voltage application unit.

[Third Embodiment]
FIG. 12 is a plan view for explaining a display element and an image display apparatus according to the third embodiment of the present invention. In the figure, the main difference between the present embodiment and the first embodiment is that three display units are stacked. In addition, about the element which is common in the said 1st Embodiment, the same code | symbol is attached | subjected and the duplicate description is abbreviate | omitted.

  That is, in FIG. 12, in the image display device 1 of the present embodiment, three display units 10a, 10b, and 10c are stacked in a direction perpendicular to the paper surface of FIG. 12, and one pixel is stacked. The unit is provided in units of 10a, 10b, and 10c. In this embodiment, signal drivers 7a, 7b, and 7c are provided, and wirings 7a1, 7b1 are provided for the terminal portions 4a1, 4b1, and 4c1 of the signal electrodes 4a, 4b, and 4c of the display units 10a, 10b, and 10c. , 7c1 are connected.

  In the present embodiment, reference drivers 8a, 8b, and 8c are provided, and wirings 8a1, 8b1 are connected to the terminal portions 5a1, 5b1, and 5c1 of the reference electrodes 5a, 5b, and 5c of the display units 10a, 10b, and 10c. , 8c1 are connected. Further, in this embodiment, scanning drivers 9a, 9b, and 9c are provided, and wirings 9a1, 9b1 are provided for the terminal portions 6a1, 6b1, and 6c1 of the scanning electrodes 6a, 6b, and 6c of the display units 10a, 10b, and 10c. 9c1 are connected.

  Here, the pixel structure of the display element 10 of the present embodiment will be specifically described with reference to FIGS.

  FIGS. 13A and 13B show the upper substrate in each of the first and second display units and the third display unit shown in FIG. 12 when viewed from the display surface side. It is an enlarged plan view which shows the principal part structure of the side. FIG. 14 is an enlarged plan view showing a main part configuration on the lower substrate side in each of the first, second, and third display units when viewed from the non-display surface side. FIG. 15 is a cross-sectional view showing a main configuration of the display element shown in FIG.

  13 to 15, the display unit 10c is similar to the display units 10a and 10b. The upper substrate 2c as the first substrate provided on the display surface side, and the back side (non-display surface) of the upper substrate 2c. And the lower substrate 3c as a second substrate provided on the side). In the display unit 10c, the upper substrate 2c and the lower substrate 3c are arranged at a predetermined interval from each other, whereby a predetermined display space Sc is formed between the upper substrate 2c and the lower substrate 3c. . In addition, in the display space Sc, the conductive liquid 16c and the insulating oil 17c that does not mix with the conductive liquid 16c are in the X direction (the left-right direction in FIG. 15) in the display space Sc. The conductive liquid 16c can move to the effective display area P1 side or the non-effective display area P2 side in the same manner as the conductive liquids 16a and 16b.

  As the conductive liquid 16c, for example, a 1 mmol / L aqueous solution of potassium chloride (KCl) is used as the conductive liquids 16a and 16b. These conductive liquids 16a, 16b, and 16c are configured such that the wavelength range of light shielded by the conductive liquid 16c is different from the wavelength range shielded by the conductive liquids 16a and 16b. On the other hand, in the conductive liquids 16a and 16b, the wavelength ranges shielded by these conductive liquids 16a and 16b may be the same.

  Specifically, in the present embodiment, the conductive liquids 16a and 16b of the display units 10a and 10b of the first layer (upper side) and the second layer (center) are made of RGB by a colorant such as a pigment or a dye. Those colored in any color are used. On the other hand, the conductive liquid 16c of the display unit 10c in the third layer (lower side) is used that is colored black by the colorant, and the conductive liquid 16c is used for light in each pixel. It functions as a shutter that allows or blocks transmission.

  The oil 17c is the same as the oils 17a and 17b, and moves inside the display space Sc as the conductive liquid 17c slides.

  For the upper substrates 2a and 2b, a transparent glass material such as a non-alkali glass substrate or a transparent transparent sheet material such as a transparent synthetic resin such as an acrylic resin is used. Further, light shielding layers 11a and 11b and water repellent films 12a and 12b are sequentially formed on the surface of the upper substrate 2a and 2b on the non-display surface side. Further, the signal electrodes 4a and 4b as the first electrodes are formed. Is provided on the water-repellent films 12a and 12b. A color filter layer Cf and a water repellent film 12c are sequentially formed on the surface of the upper substrate 2c on the non-display surface side. Further, the signal electrode 4c as the first electrode is formed on the water repellent film 12c. Is provided.

  In addition, the lower substrates 3a, 3b, 3c, like the upper substrates 2a, 2b, 2c, are transparent glass materials such as non-alkali glass substrates or transparent transparent sheet materials such as transparent synthetic resins such as acrylic resins. Is used. The reference electrodes 5a, 5b, and 5c as second electrodes and the scanning electrodes 6a, 6b, and 6c as third electrodes are provided on the surface of the lower substrate 3a, 3b, and 3c on the display surface side. Furthermore, dielectric layers 13a, 13b, 13c are formed so as to cover these reference electrodes 5a, 5b, 5c and scan electrodes 6a, 6b, 6c. In addition, ribs 14y1 and 14x1 are provided on the surface of the dielectric layer 13a on the display surface side so as to be parallel to the Y direction and the X direction, respectively. Similarly, ribs 14y2 and 14x2 are provided on the surface of the dielectric layer 13b on the display surface side so as to be parallel to the Y direction and the X direction, respectively. Similarly, ribs 14y3 and 14x3 are provided on the surface on the display surface side of the dielectric layer 13c so as to be parallel to the Y direction and the X direction, respectively.

  The lower substrate 3a is provided with a water repellent film 15a so as to cover the dielectric layer 13a and the ribs 14x1 and 14y1, and the lower substrate 3b is provided so as to cover the dielectric layer 13b, the ribs 14x2 and 14y2. A water repellent film 15b is provided. Similarly, in the lower substrate 3c, a water repellent film 15c is provided so as to cover the dielectric layer 13c and the ribs 14x3 and 14y3.

  Further, a backlight 18 that emits white illumination light, for example, is integrally assembled on the back side (non-display surface side) of the lower substrate 3c, and the transmissive display element 10 is configured. In the present embodiment, as in the above-described embodiment, an appropriate display operation can be performed even when the outside light is insufficient or at night, and the gradation range is large and the gradation is highly accurate. The high-luminance display element 10 that can be easily controlled can be easily configured.

  In the display unit 10c, as in the display units 10a and 10b, the scanning operation is performed by applying the voltage shown in Table 1 or Table 2.

  Here, the gradation display operation in the present embodiment configured as described above will be specifically described with reference to FIGS. In the following description, an operation with a red pixel will be described as an example. In the following description, for the sake of simplicity of explanation, a case where the transmission wavelength region of the conductive liquid 16a and the transmission wavelength region of the color filter portion Cfr are the same will be described as an example.

  16 is a cross-sectional view for explaining an example of operation of the display element shown in FIG. 12, and FIG. 17 is a cross-sectional view for explaining another example of operation of the display element shown in FIG. 18 is a cross-sectional view for explaining another example of operation of the display element shown in FIG. 12, and FIG. 19 is a cross-sectional view for explaining another example of operation of the display element shown in FIG.

  As shown in FIG. 15, the conductive liquids 16a and 16b of the display units 10a and 10b are moved to the scanning electrodes 6a and 6b (ineffective display area P2) side, and the conductive liquid 16c of the display unit 10c is moved to the reference electrode 5c ( When moved to the effective display area P1) side, the illumination light from the backlight 18 is blocked by the conductive liquid 16c colored black. As a result, the illumination light is prevented from reaching the color filter portion Cfr, and the display color on the display surface side of the red pixel is in a black display state by the conductive liquid 16c.

  Further, as shown in FIG. 16, the conductive liquid 16a of the display unit 10a, the conductive liquid 16b of the display unit 10b, and the conductive liquid 16c of the display unit 10c are scanned electrodes 6a, 6b, 6c (ineffective display region P2). ), The illumination light from the backlight 18 is allowed to reach the color filter portion Cfr. Then, the illumination light sequentially passes through the color filter portion Cfr and the transparent portions 11t2 and 11t1, and is emitted to the outside. As a result, the display color on the display surface side of the red pixel is in a red display state by the color filter portion Cfr.

  In addition, as shown in FIG. 17, the conductive liquid 16a of the display unit 10a and the conductive liquid 16c of the display unit 10c are moved to the scanning electrodes 6a and 6c (ineffective display area P2) side, and the conductivity of the display unit 10b. When the liquid 16b is moved to the reference electrode 5a (effective display area P1) side, the illumination light from the backlight 18 passes through the color filter portion Cfr and then passes through the inside of the conductive liquid 16b colored in red. . Thereafter, the illumination light sequentially passes through the transparent portions 11t2 and 11t1 and is emitted to the outside. As a result, the display color on the display surface side of the red pixel is in a red display state by the color filter portion Cfr and the conductive liquid 16b.

  In the case shown in FIG. 17, the display color on the display surface side of the red pixel is reduced in luminance by the amount that has passed through the inside of the conductive liquid 16 b as compared with the case shown in FIG. 16. The display becomes dark red. That is, in the case shown in FIG. 17, a part of the illumination light is absorbed by the conductive liquid 16b, and the amount of red light emitted to the outside is reduced compared to the case shown in FIG.

  As shown in FIG. 18, the conductive liquid 16a of the display unit 10a and the conductive liquid 16b of the display unit 10b are moved to the reference electrodes 5a and 5b (effective display area P2) side, and the conductive liquid of the display unit 10c. When 16c is moved to the scanning electrode 6c (non-effective display area P1) side, the illumination light from the backlight 18 passes through the inside of the conductive liquid 16b after passing through the color filter portion Cfr. Thereafter, the illumination light passes through the transparent portion 11t2, and further passes through the inside of the conductive liquid 16a colored in red and the transparent portion 11t1, and then is emitted to the outside. As a result, the display color on the display surface side of the red pixel is in a red display state by the color filter portion Cfr and the conductive liquids 16a and 16b.

  In the case shown in FIG. 18, the display color on the display surface side of the red pixel is reduced in luminance by the amount that has passed through the inside of the conductive liquid 16 a compared to the case shown in FIG. 17. The display becomes dark red. That is, in the case shown in FIG. 18, a part of the illumination light is absorbed by the conductive liquid 16a, and the amount of red light emitted to the outside is reduced compared to the case shown in FIG.

  Further, as shown in FIG. 19, the conductive liquid 16a of the display unit 10a is moved to the reference electrode 5a (effective display area P2) side, and the conductive liquid 16b of the display unit 10b and the conductive liquid 16c of the display unit 10c are moved. When moved to the scanning electrodes 6b, 6c (ineffective display area P1) side, the illumination light from the backlight 18 passes through the transparent part 11t2 after passing through the color filter part Cfr. Thereafter, the illumination light sequentially passes through the inside of the conductive liquid 16a and the transparent portion 11t1, and then is emitted to the outside. As a result, the display color on the display surface side of the red pixel is in a red display state by the color filter portion Cfr and the conductive liquid 16a.

  In the case shown in FIG. 19, the display color on the display surface side of the red pixel is reduced in luminance by the amount that has passed through the inside of the conductive liquid 16 a compared to the case shown in FIG. 16. The display becomes dark red. That is, in the case shown in FIG. 19, a part of the illumination light is absorbed by the conductive liquid 16a, and the amount of red light emitted to the outside is reduced compared to the case shown in FIG.

  Further, in the case shown in FIG. 19, when the transmission wavelength region of the conductive liquid 16a and the transmission wavelength region of the conductive liquid 16b are different from each other, the display with the red pixel is performed as compared with the case shown in FIG. The display color on the surface side is bright red. When the transmission wavelength region of the conductive liquid 16a is the same as that of the conductive liquid 16b, the display color on the display surface side of the red pixel is the same as that shown in FIG.

  As described above, in the red pixel, the gradation display of five gradations shown in FIGS. 15 to 19 is performed. Further, in the image display device 1, the conductive liquids 16a, 16b, and 16c move to the ineffective display region P2 side in all three adjacent RGB pixels as shown in FIG. When color display is performed, white light is displayed by mixing red light, green light, and blue light from the RGB pixels with white light.

  With the above configuration, the present embodiment can achieve the same operations and effects as the first embodiment. In the present embodiment, since the three display units 10a, 10b, and 10c are stacked so that the effective display areas P1 face each other, as shown in FIGS. It is possible to easily adjust the display color to 5 gradation levels.

  The above embodiments are all illustrative and not restrictive. The technical scope of the present invention is defined by the claims, and all modifications within the scope equivalent to the configurations described therein are also included in the technical scope of the present invention.

  For example, in the above description, the case where the present invention is applied to an image display apparatus provided with a display unit capable of displaying a color image display has been described. However, the present invention provides a display unit that displays information including characters and images. There is no limitation as long as it is an electric device provided, for example, a personal digital assistant such as a PDA such as an electronic notebook, a display device attached to a personal computer, a TV, etc., or electronic paper and other electric devices equipped with various display units. It can use suitably for an apparatus.

  In the above description, the case where the electrowetting type display element that moves the conductive liquid in accordance with the application of the electric field to the conductive liquid is described. However, the display element of the present invention is not limited to this. It is not limited, and any electric field induction type display element that can change the display color on the display surface side by operating a conductive liquid inside the display space using an external electric field is not limited. However, the present invention can be applied to other types of electric field induction display elements such as an electroosmosis method, an electrophoresis method, and a dielectrophoresis method.

  However, when the electrowetting type display element is configured as in the above embodiments, the conductive liquid can be moved at a high speed with a low driving voltage. Moreover, since the conductive liquid is slid and moved by providing three electrodes, it is easy to increase the display color switching speed and save labor compared to the one that changes the shape of the conductive liquid. Can be aimed at. Therefore, it is preferable in that moving image display can be easily performed and a display element having excellent display performance can be easily configured. Further, an electrowetting type display element is preferable in that the display color is changed in accordance with the movement of the conductive liquid, and therefore, unlike a liquid crystal display device or the like, there is no viewing angle dependency. Furthermore, since it is not necessary to provide a switching element for each pixel, it is also preferable in that a high-performance matrix driving display element having a simple structure can be configured at low cost. In addition, since a birefringent material such as a liquid crystal layer is not used, it is also preferable in that a high-luminance display element excellent in light utilization efficiency of light from the backlight and external light used for information display can be easily configured. .

  In the above description, the case where a transmissive display element including a backlight is configured has been described. However, the present invention is not limited to this, and a reflective type having a light reflecting portion such as a diffuse reflector. In addition, the present invention can also be applied to a transflective display element in which the light reflecting portion and the backlight are used in combination.

  Further, in the above description, the case where two or three display units are used has been described. However, in the present invention, N (N is an integer of 2 or more) so that the effective display areas face each other. Any display unit may be used.

  In the above description, the case where the conductive liquid colored in black and the color filter layer are used in the display unit installed in the lowermost layer has been described. As long as the conductive liquid is configured to shield light in a predetermined wavelength range, the configuration of the conductive liquid, the presence or absence of the color filter layer, the installation location, and the like are not limited to those described above. For example, each of the N display units may have a configuration in which the transmittance of the conductive liquid is different from each other.

  However, as in each of the above-described embodiments, when the conductive liquid colored in black is used for at least one display unit, the display unit can function as a shutter, and black display is appropriately performed. It is preferable at the point which can be performed.

  Further, as in each of the above embodiments, the halftone reproduction (display) range can be more easily expanded when the color filter portion colored in a predetermined color is provided in at least one display unit. This is preferable.

  Further, as in the above embodiments, in each of the plurality of display units, by changing the colorant used for the conductive liquid, the wavelength range of the light shielded by the conductive liquid is made different. However, it is preferable in that the light shielding areas by the conductive liquid can be made different.

  In the above description, the case where pixels of each color of RGB are provided on the display surface side has been described. However, the present invention is not limited to this, and a plurality of pixel regions can display full color on the display surface side. What is necessary is just to be provided according to each of a plurality of possible colors. Specifically, conductive liquids of a plurality of colors colored in RGB, cyan (C), magenta (M), yellow (Y), CMY, or RGBYC can be used.

  In the above description, a case where a plurality of pixels are configured in units of two or three display units has been described. However, the present invention is not limited to this. For example, two adjacent three pixels You may comprise a pixel per display unit. That is, each of the two display units may be configured as a sub-pixel (sub-pixel).

  In the above description, the case where the reference electrode (second electrode) and the scanning electrode (third electrode) are provided on the effective display area side and the non-effective display area side has been described. The present invention is not limited, and the second electrode and the third electrode may be provided on the non-effective display area side and the effective display area side, respectively.

  In the above description, the case where the reference electrode (second electrode) and the scanning electrode (third electrode) are provided on the surface of the lower substrate (second substrate) on the display surface side is described. However, the present invention is not limited to this, and the second and third electrodes embedded in the second substrate made of an insulating material can also be used. In such a configuration, the second substrate can be used as a dielectric layer, and the installation of the dielectric layer can be omitted. Further, the first electrode may be directly provided on the first and second substrates also serving as the dielectric layer, and the first electrode may be installed inside the display space.

  In the above description, the case where the reference electrode (second electrode) and the scanning electrode (third electrode) are configured using a transparent electrode material has been described. However, the present invention describes the second and third electrodes. Of these, only one electrode disposed so as to face the effective display area of the pixel may be formed of a transparent electrode material, and the other electrode not opposed to the effective display area may include aluminum, silver, chromium, and the like. Opaque electrode materials such as metals can be used.

  In the above description, the case where the strip-shaped reference electrode (second electrode) and the scanning electrode (third electrode) are used has been described. However, the shapes of the second and third electrodes of the present invention are the same. It is not limited at all. For example, in a reflective display element in which the use efficiency of light used for information display is lower than that of a transmissive type, the shape may be such that light loss such as a line shape or a net shape hardly occurs.

  Further, in the above description, the case where a linear wiring is used for the signal electrode (first electrode) has been described. However, the first electrode of the present invention is not limited to this, and other wiring such as a mesh wiring is used. Wiring formed in the shape of can also be used.

  However, as in each of the above-described embodiments, an opaque material is used when the shape of the first electrode is determined using the transmittance of the second and third electrodes using transparent transparent electrodes. Even when the first electrode is used, it is preferable in that the shadow of the first electrode can be prevented from appearing on the display surface side, and the display quality can be prevented from being lowered. The use of linear wiring is more preferable in that the deterioration in display quality can be reliably suppressed.

  In the above description, the aqueous solution of potassium chloride is used as the conductive liquid, and the signal electrode (first electrode) is configured using at least one of gold, silver, copper, platinum, and palladium. As described above, the present invention is such that the first electrode that is installed inside the display space and is in contact with the conductive liquid uses a material that is electrochemically inert to the conductive liquid. There is no limitation. Specifically, the conductive liquid includes zinc chloride, potassium hydroxide, sodium hydroxide, alkali metal hydroxide, zinc oxide, sodium chloride, lithium salt, phosphoric acid, alkali metal carbonate, oxygen ion conductivity. What contains electrolytes, such as ceramics which have this, can be used. In addition to water, organic solvents such as alcohol, acetone, formamide, and ethylene glycol can also be used as the solvent. Furthermore, the conductive liquid of the present invention includes an ionic liquid containing a cation such as pyridine, alicyclic amine, or aliphatic amine, and an anion such as fluoride such as fluoride ion or triflate. (Normal temperature molten salt) can also be used.

  However, as in each of the above-described embodiments, when an aqueous solution in which a predetermined electrolyte is dissolved is used as the conductive liquid, a display element that is excellent in handleability and easy to manufacture can be easily configured. This is preferable.

  The first electrode of the present invention includes, for example, an electrode body using a conductive metal such as aluminum, nickel, iron, cobalt, chromium, titanium, tantalum, niobium, or an alloy thereof; Passivation with an oxide coating provided to cover the surface can be used.

  However, when using at least one of gold, silver, copper, platinum, and palladium for the first electrode and the electrode member as in each of the above embodiments, a metal having a low ionization tendency is used. In addition, while simplifying the electrode, it is possible to reliably prevent an electrochemical reaction with the conductive liquid, and to easily configure a long-life display element in which a decrease in reliability is prevented. This is preferable in that it can be performed. In addition, since the metal with a small ionization tendency can relatively reduce the interfacial tension generated at the interface with the conductive liquid, the conductive liquid is stabilized at the fixed position when the conductive liquid is not moved. It is also preferable because it can be easily held in a state.

  In the above description, the case where nonpolar oil is used has been described. However, the present invention is not limited to this, and any insulating fluid that does not mix with the conductive liquid may be used. Instead, air may be used. Moreover, silicone oil, aliphatic hydrocarbons, etc. can be used as oil.

  However, as in each of the above embodiments, the nonpolar oil that is not compatible with the conductive liquid is more conductive in the nonpolar oil than the case where air and the conductive liquid are used. It is preferable in that the liquid droplets of the conductive liquid can move more easily, the conductive liquid can be moved at high speed, and the display color can be switched at high speed.

  INDUSTRIAL APPLICABILITY The present invention is useful for a display element that can perform halftone display with high accuracy and a high-performance electric apparatus using the display element.

1 is a plan view illustrating a display element and an image display device according to a first embodiment of the present invention. (A) And (b) is an enlarged plan view which shows the principal part structure by the side of the upper board | substrate in the display unit of the 1st layer and the 2nd layer which were shown in FIG. . It is an enlarged plan view which shows the principal part structure by the side of the lower board | substrate in each display unit of the said 1st layer and the 2nd layer when it sees from the non-display surface side. It is sectional drawing which shows the principal part structure of the said display element. It is a figure explaining the operation example in the said display unit. It is sectional drawing explaining the operation example of the said display element. It is sectional drawing explaining another example of operation | movement of the said display element. It is a top view explaining the display element concerning 2nd Embodiment of this invention, and an image display apparatus. It is sectional drawing which shows the principal part structure of the display element shown in FIG. FIG. 9 is a cross-sectional view illustrating an operation example of the display element illustrated in FIG. 8. FIG. 9 is a cross-sectional view illustrating another example of the operation of the display element illustrated in FIG. It is a top view explaining the display element and image display apparatus concerning the 3rd Embodiment of this invention. (A) And (b) is the principal part by the side of the upper board in each display unit of the 1st layer shown in Drawing 12, and the display unit of the 3rd layer shown in Drawing 12, respectively, when it sees from the display surface side It is an enlarged plan view which shows a structure. FIG. 4 is an enlarged plan view showing a configuration of a main part on the lower substrate side in each of the first, second, and third display units when viewed from the non-display surface side. It is sectional drawing which shows the principal part structure of the display element shown in FIG. FIG. 13 is a cross-sectional view illustrating an operation example of the display element illustrated in FIG. 12. FIG. 13 is a cross-sectional view illustrating another example of the operation of the display element illustrated in FIG. FIG. 13 is a cross-sectional view illustrating another example of the operation of the display element illustrated in FIG. FIG. 13 is a cross-sectional view illustrating another example of the operation of the display element illustrated in FIG.

Explanation of symbols

1 Image display device (electric equipment)
2a, 2b, 2c Upper substrate (first substrate)
3a, 3b, 3c Lower substrate (second substrate)
4a, 4b, 4c Signal electrode (first electrode)
5a, 5b, 5c Reference electrode (second electrode)
6a, 6b, 6c Scan electrode (third electrode)
7a, 7b, 7c Signal driver (signal voltage application unit)
8, 8a, 8b, 8c Reference driver (reference voltage application unit)
9, 9a, 9b, 9c Scan driver (scan voltage application unit)
10 Display element (display unit)
10a, 10b, 10c Display unit 14x1, 14x2, 14x3, 14y1, 14y2, 14y3 Rib (partition wall)
16a, 16b, 16c Conductive liquid Sa, Sb, Sc Display space P Pixel area P1 Effective display area P2 Ineffective display area Cfr, Cfg, Cfb Color filter section

Claims (9)

A second substrate provided on the non-display surface side of the first substrate so that a predetermined display space is formed between the first substrate provided on the display surface side and the first substrate. The effective display area and the ineffective display area that are set with respect to the display space, and the display space, and are movably enclosed in the effective display area side or the ineffective display area side within the display space. A display element comprising a display unit having a conductive liquid,
N display units (N is an integer of 2 or more) are stacked such that the effective display regions face each other,
In each of the N display units, the conductive liquid is configured to shield light in a predetermined wavelength range.
A display element characterized by the above. The display unit is provided with a plurality of first electrodes along a predetermined arrangement direction on one side of the first and second substrates,
The effective display area on the other side of the first and second substrates such that a plurality of second electrodes and a plurality of third electrodes alternately and intersect with the plurality of first electrodes. On one side and the other side of the side and the ineffective display area side,
The plurality of first electrodes are used as a plurality of signal electrodes, respectively.
The plurality of second electrodes are used as one of a plurality of reference electrodes and a plurality of scan electrodes, respectively, and
The plurality of third electrodes are used as the other of the plurality of reference electrodes and the plurality of scan electrodes, respectively.
The display unit is connected to the plurality of reference electrodes, and applies a predetermined reference voltage to each of the plurality of reference electrodes.
A signal voltage applying unit that is connected to the plurality of signal electrodes and applies a signal voltage corresponding to information displayed on the display surface side to each of the plurality of signal electrodes;
The conductive voltage is connected to the plurality of scan electrodes and is connected to the plurality of scan electrodes when the reference voltage application unit applies the reference voltage to the plurality of reference electrodes. A non-selection voltage that prevents the liquid from moving inside the display space, and a selection voltage that allows the conductive liquid to move inside the display space according to the signal voltage. The display element according to claim 1, further comprising a scanning voltage application unit that applies one voltage. A plurality of pixels are provided in the N display unit units,
3. The pixel areas of the plurality of pixels are provided in units of intersections between the signal electrodes and the scanning electrodes, and the display spaces are partitioned by partition walls in the pixel areas. The display element as described in. The display element according to claim 3, wherein the plurality of pixels are provided in accordance with a plurality of colors capable of full color display on the display surface side. 5. The display element according to claim 2, wherein one of the reference voltage application unit and one of the scanning voltage application units is shared in the N display units. 6. Each of the N display units has a different wavelength range of light shielded by the conductive liquid by changing a colorant used for the conductive liquid. The display element according to item. The display element according to claim 1, wherein the display unit is provided with a color filter portion of a predetermined color on the effective display area side. The display element according to claim 1, wherein in the N display units, the conductive liquid of the one display unit is colored black. An electrical device having a display unit for displaying information including characters and images,
An electrical apparatus using the display element according to claim 1 for the display unit.

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