JP7158208B2 - Electrofluidic display device and composite display device - Google Patents

Description

The present invention relates to an electrofluidic display device and a composite display device using the same.

In recent years, an electrofluidic display (electrofluidic display) as disclosed in Patent Document 1 has attracted attention.

Electrofluidic displays generally comprise two opposing substrates, at least one of which is transparent, for each pixel, and a shielding plate provided between the two substrates. An exposed space is formed between the shielding plate and the transparent substrate that is visible through the substrate from the outside of the transparent substrate. Between the shielding plate and the other substrate, a hidden space that cannot be visually recognized from the outside is formed. The exposed space and the concealed space are provided in communication with each other. These spaces are sealed with a transparent non-polar oil and a polar liquid that is not mixed with the oil and is colored, for example, black.
Electrodes are provided in the exposed space and the hidden space, and the electric field generated by applying a voltage to the electrodes changes the contact angle of the portion of the interface between the liquid and the oil that contacts the wall forming each space, Liquids and oils can easily move in each space. Since the liquid has polarity, it moves between the exposed space and the hidden space according to the voltage applied to the electrodes.

Since the exposed space is visible from the outside of the transparent substrate, by moving the liquid colored in black or the like so as to fill the exposed space, a state in which the pixels are displayed in black can be realized. Conversely, by moving the liquid to fill the hidden space and the oil to fill the exposed space, the shielding plate can be seen through the oil from the outside of the transparent substrate. You can achieve the state displayed in white. In addition, intermediate colors can be expressed by moving the liquid and the oil so that they fill the exposed space half by half.
In the electrofluid display, as described above, gradation can be expressed by changing the proportion of liquid in the exposed space.

Conventionally, electrophoretic displays using electrophoretic technology are often used, for example, in non-self-illuminating electronic readers. Electrophoretic displays have drawbacks such as difficulty in displaying moving images and images with gradation. On the other hand, an electrofluid display has a high response speed and may be able to display moving images, and can also express gradations as described above. Therefore, the electrofluid display is expected as a new display to replace, for example, the electrophoretic display.

U.S. Patent Application Publication No. 2013/0033476

In conventional electrofluid displays such as those described above, it is difficult to express through the display.
For example, assume that the two substrates and the shielding plate that constitute the electrofluid display are all made of a transparent material. In this case, the concealed space is also visible from the outside through the substrate and the shielding plate, so the colored liquid that has moved into the concealed space is also visible from the outside. Therefore, in the electrofluid display provided with the concealed space and the exposed space as described above, even if the state with the highest transmittance is expressed, it means that the colored liquid moves to the concealed space and the exposed space by the same volume. , the colored liquid located in the concealed space and the colored liquid located in the exposed space are displayed overlapping each other. That is, the maximum transmittance of the electrofluid display having the structure described above is, for example, about 50%.
If the transmittance of an electrofluidic display can be increased, it can be applied to digital signage, for example. That is, in order to expand the application range of electrofluid displays, it is desired to improve the transmittance.

The problem to be solved by the present invention is to provide an electrofluidic display device and a composite display device capable of transmissive display with high transmittance.

In order to solve the above problems, the present invention employs the following means. That is, in the present invention, pixel elements are provided on first and second transparent substrates provided to face each other, and on at least one of the first and second transparent substrates at the boundaries of the pixel elements. a black matrix forming an opaque region that does not transmit light; first and second spaces communicating with each other formed between the first and second transparent substrates; one of which is colored and the other is transparent; , a polar fluid and a non-polar fluid sealed in the first and second spaces; and first and second electrodes provided in the first and second spaces, respectively. The electrofluid display device is provided, wherein the first space is formed in a transmissive area that transmits light, and the second space is formed in the non-transmissive area.
According to the configuration as described above, both the first and second substrates are transparent substrates, and the first space is provided in the transmission region through which light is transmitted through the first and second transparent substrates. Therefore, the first space can be visually recognized from the outside. Also, the second space is formed in a non-transmissive region that is formed by a black matrix and does not transmit light. Therefore, by applying a voltage to the first and second electrodes, it is possible to move, for example, a colored fluid into the second space and a transparent fluid into the first space formed in the transmissive region, respectively. . In this case, the light transmitted through one substrate from the outside in the transmissive region and entering the inside of the pixel element reaches the other substrate after passing through the transparent fluid that fills the first space, and is transmitted therethrough. In addition, since the colored fluid is hidden in the non-transmissive area by the black matrix, it does not block the light entering the transmissive area. This makes it possible to realize an electrofluid display device with high transparency.

In one aspect of the present invention, a partition that partitions the first and second spaces is provided between the first and second spaces, the partition has two communication holes, The second space is communicated by the two communicating holes, and the first and second electrodes are provided biased to one side of the two communicating holes.
According to the configuration as described above, the first and second spaces are communicated with each other through the two communication holes, and each electrode is biased toward one side of the two communication holes. For this reason, for example, when one space is filled with a polar fluid and the other space is filled with a non-polar fluid, by appropriately applying a voltage to the electrodes, the side on which the electrodes are unevenly provided can be communicated. A polar fluid can pass through the holes to the other space. The nonpolar fluid filled in the other space moves to the one space through the other communication hole so that the nonpolar fluid is pushed out by the polar fluid that has flowed into the other space. . Since the movement of each fluid can be easily controlled in this way, the gradation can be appropriately expressed.

In another aspect of the present invention, the transmissive region of the first transparent substrate is provided with a transparent wall such that the surface thereof approaches the second transparent substrate, and the first space is the transparent wall. is formed between the surface of the wall and the second transparent substrate.
According to the configuration as described above, it is possible to form the transmissive region while reducing the thickness of the first space in the direction orthogonal to each substrate, regardless of the distance between the first transparent substrate and the second transparent substrate. can be done. By thinning the first space in this way, the volume of the first space can be reduced, and the amount of fluid sealed in each space can be reduced. That is, since the amount of fluid that must move when a voltage is applied to the electrodes is reduced, the reaction speeds up and the image display speed can be improved.

In another aspect of the present invention, the pixel element includes a boundary wall that separates the pixel element from the outside at the boundary of the pixel element, and the side surface of the transparent wall body is separated from the transmissive area and the non-transmissive area. The second space is defined by the side surface of the transparent wall and the boundary wall provided at the boundary of the area.
According to the configuration as described above, the second space is defined by the side surface of the transparent wall provided at the boundary between the transmissive region and the non-transmissive region, so that the second space is reliably formed in the non-transmissive region. be done. This improves the transmittance of the electrofluidic display device.

In another aspect of the present invention, the pixel element is formed in a rectangular parallelepiped shape and has a rectangular shape when viewed in plan from an orthogonal direction orthogonal to the first transparent substrate, and the black matrix has at least the rectangular shape. provided along the long side, the first space is formed in a plate shape, extends along the second transparent substrate in the direction in which the second transparent substrate extends, and Long sides are provided to extend along the long sides of the rectangular shape, the second space is also formed in a plate shape, and each of the long sides and short sides of the second space is the long side of the rectangular shape. It is provided so as to extend along each of the sides and the orthogonal direction.
According to the configuration as described above, the first space can be formed to have substantially the same shape and substantially the same size as the transmissive region of the pixel element.
In addition, the sides of the plate-shaped second space extending in the orthogonal direction perpendicular to the substrates are short sides. For example, if the side extending in the orthogonal direction is the long side, the distance between the first and second substrates may have to be unreasonably large. Further, for example, when the side extending in the orthogonal direction is the side in the thickness direction, both the long side and the short side are positioned parallel to each substrate, so the area of the second space on each substrate is It becomes unreasonably large, resulting in a decrease in transmittance. As in the above configuration, by making the side extending in the orthogonal direction the short side direction, the distance between the substrates can be maintained at an appropriate distance and the manufacturing can be facilitated. The area of the second space occupied on the substrate as the long side and the side in the thickness direction can be reduced, and the transmittance can be increased.

In another aspect of the present invention, the side length in the thickness direction of the second space is smaller than the width of the black matrix.
According to the configuration as described above, it is possible to reliably hide the second space in the non-transmissive area formed by the black matrix. This improves the transmittance of the electrofluidic display device.

In another aspect of the present invention, an electrofluidic display device comprises a plurality of pixels, each pixel having a first, a second, a different one of said polar fluid and said non-polar fluid as sub-pixels. and a third colored pixel element.
According to the above configuration, one pixel of an electrofluidic display can be realized by a plurality of pixel elements in which fluids colored with different colors are sealed. , color display becomes possible.

In another aspect of the invention, it comprises an electrofluidic display device as described above, and a transparent display device, said electrofluidic display device and said transparent display device comprising: said pixel element of said electrofluidic display device; A composite display device is provided in which each sub-pixel constituting each pixel of the transparent display device is superimposed so as to correspond to each other.
According to the configuration as described above, for example, in all pixel elements of the electrofluid display device, the colored fluid is moved to the second space side to set the electrofluid display device in a transmissive state, thereby forming a composite display device. It can be used as a transparent display device. In this case, the composite display device can be suitably used for digital signage, for example. In addition, the composite display device can be used as a non-transmissive display device by moving the colored fluid to the first space side in all the pixel elements to bring the electrofluid display device into an opaque state, that is, a light-shielding state. is. In this case, the composite display device can be used for digital signage as described above, and can also display and view images as a normal display, for example.
Thus, the availability of transparent display devices overlaid with electrofluidic display devices is enhanced.

In another aspect of the present invention, in the composite display device as described above, one of the polar fluid and the non-polar fluid of the electrofluidic display device is colored black.
The configuration as described above is suitable when the composite display device is used as an opaque display device.

In another aspect of the present invention, in the composite display device as described above, the electrofluidic display device is provided over both surfaces of the transparent display device.
According to the configuration as described above, the composite display device can be used as a transparent display device, for example, by setting both electrofluidic display devices in a transmissive state. In addition, since the electrofluid display devices are provided on both surfaces of the transparent display device, an image displayed on the transparent display device can be displayed by making an arbitrary electrofluid display device in an opaque state and the other in a transmissive state. can be displayed and visible only in an arbitrary direction. Thus, the availability of transparent display devices overlying electrofluidic display devices is enhanced.

According to the present invention, it is possible to provide an electrofluid display device and a composite display device capable of transmissive display with high transmittance.

1 is a schematic plan view of an electrofluid display device according to a first embodiment of the present invention; FIG. Fig. 3 is a perspective view of a pixel element of the electrofluidic display device; 4 is a cross-sectional view of the pixel element; FIG. 4 is a vertical cross-sectional view of the pixel element; FIG. 4 is a vertical cross-sectional view of the pixel element; FIG. Fig. 3 is a perspective view of first and second spaces of the pixel element; FIG. 4 is an explanatory diagram of the operation of the electrofluid display device; FIG. 4 is an explanatory diagram of the operation of the electrofluid display device; FIG. 4 is an explanatory diagram of the operation of the electrofluid display device; FIG. 4 is an explanatory diagram of the operation of the electrofluid display device; FIG. 7 is a schematic exploded perspective view of a composite display device according to a second embodiment of the invention; FIG. 11 is a schematic exploded perspective view of a composite display device in a modified example of the second embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the electrofluid display device of this embodiment, the pixel elements are provided on first and second transparent substrates facing each other, and at the boundaries of the pixel elements on at least one of the first and second transparent substrates. A black matrix provided to form an opaque region that does not transmit light, and first and second spaces communicating with each other formed between the first and second transparent substrates, one of which is colored and the other of which is colored. a polar fluid and a non-polar fluid sealed in the first and second spaces, and first and second electrodes provided in each of the first and second spaces; In the display device, the first space is formed in the transmissive area that transmits light, and the second space is formed in the non-transmissive area.

[First embodiment]
FIG. 1 is a schematic plan view of an electrofluid display device according to the first embodiment. The electrofluid display device 1 includes an image processing section 2 , a gate line driving section 3 , a data line driving section 4 and a display section 5 .
The display unit 5 includes a plurality of pixels 8 arranged in a matrix. A gate line 6 connects the gate line driver 3 and each row of aligned pixels 8 . A data line 7 connects the data line driving section 4 and each column of aligned pixels 8 .
The image processing section 2 generates an image to be displayed on the display section 5 and transmits it to the gate line driving section 3 and the data line driving section 4 .
Upon receiving an image, the gate line driving section 3 and the data line driving section 4 appropriately select the gate line 6 and the data line 7 corresponding to each pixel 8 constituting the image, and Appropriate voltage is applied as a pixel value to be displayed by . Each pixel 8 performs gradation display based on the applied voltage level.
In this embodiment, each pixel 8 is driven by an active matrix.

Each pixel 8 comprises, for example, three pixel elements 10 . More specifically, in this embodiment, as sub-pixels, for example, a first pixel element 10R that displays red, a second pixel element 10G that displays green, and a third pixel element 10B that displays blue are provided. .
Each pixel element 10R, 10G, 10B is structurally equivalent. As will be described later, the electrofluid display device 1 of this embodiment expresses gradation by controlling the positions of a polar fluid and a non-polar fluid, one of which is colored and the other of which is transparent. That is, these pixel elements 10R, 10G, and 10B are colored with first, second, and third colors (for example, red, green, and blue in the present embodiment) that are different from each other in the fluid, so that each The pixels 8 are capable of color display in which these colors are combined.
Therefore, hereinafter, the pixel elements 10R, 10G, and 10B will be described as the pixel element 10 without any particular distinction.

FIG. 2 is a perspective view of the pixel element 10 when the direction of light transmission is the vertical direction on the paper surface. FIG. 3 is a cross-sectional view of the AA portion of FIG. 2, more specifically, at a position crossing the first space S1, which will be described later. 4(a) and 4(b) are longitudinal cross-sectional views taken along line BB and line CC of FIG. 3, respectively. 5(a) and 5(b) are vertical cross-sectional views taken along line DD and line FF of FIG. 3, respectively. FIG. 6 is a perspective view of a first space S1 and a second space S2, which will be described later.
The pixel element 10 includes a first transparent substrate 11, a second transparent substrate 12, a black matrix 13, a boundary wall 14, a transparent wall 15, a first electrode E1 and a second electrode E2. In FIG. 2 , the boundary wall 14 is indicated by a chain double-dashed line, and the internal structure is mainly drawn by seeing through the boundary wall 14 .

The first transparent substrate 11 and the second transparent substrate 12 are provided facing each other with a gap in the light transmission direction, that is, the thickness direction Z of the pixel element 10 .
The first and second transparent substrates 11 and 12 are made of a transparent material such as glass or transparent polyimide resin.
In the present embodiment, the pixel element 10 is formed in a rectangular parallelepiped shape, and when viewed in plan from the orthogonal direction perpendicular to the first transparent substrate 11, that is, the thickness direction Z of the pixel element 10, the long side 10a and the short side 10b are separated from each other. It has a rectangular shape.

The black matrix 13 is provided on the first transparent substrate 11 side, that is, the inner surface 12b of the second transparent substrate 12 .
The black matrix 13 is provided at a boundary portion of the pixel element 10 with a substantially constant width so as to form a frame surrounding the center portion of the pixel element 10 . Thus, the black matrix 13 is provided along at least the long side 10a of the pixel element 10. As shown in FIG.
The black matrix 13 is made of a material with low transmittance, such as low-reflection chrome or resin black resist. Thereby, as shown in FIGS. 4 and 5, an opaque region R2 that does not transmit light in the thickness direction Z is formed. In the area where the black matrix 13 is not formed, the pixel element 10 is basically formed of a highly transparent material, and serves as a transmissive area R1 that transmits light.

A cylindrical boundary wall 14 is provided between the black matrix 13 formed on the second transparent substrate 12 and the first transparent substrate 11 so as to surround the central portion of the pixel element 10 . More specifically, as shown in FIG. 3, the boundary wall 14 includes two boundary walls 14A and 14B extending in the direction X along which the long side 10a extends, and two boundary walls 14A and 14B extending in the direction Y along which the short side 10b extends. It has two extending boundary walls 14C, 14D.
An outer side surface 14d of the boundary wall 14 serves as a boundary 14d of the pixel element 10 that separates the outside of the pixel element 10, that is, from other adjacent pixel elements 10. As shown in FIG. The boundary wall 14 has a thickness equal to or less than the width of the black matrix 13 . Therefore, the inner side surface 14c of the boundary wall 14 is located under the black matrix 13, and the entire boundary wall 14 is hidden by the black matrix 13 so that the boundary wall 14 does not block the light transmitted in the thickness direction Z. ing. The boundary wall 14 is made of resin, for example.

As shown in FIG. 5, one side 14A of the boundary wall 14 extending in the long side direction X is formed particularly thin, and a space is provided between the inner side surface 14c and the inner edge of the black matrix 13. there is In this embodiment, as shown in FIG. 5, each pixel element 10 is described as having this one boundary wall 14A, but this is not the only option. For example, the pixel element 10 may have substantially no boundary wall 14A, and the outer side surface 14d of the boundary wall 14B of another adjacent pixel element 10 may be the inner side surface 14c of the pixel element 10 in that direction. do not have.

A transparent wall (transparent wall) 15 is provided on the inner surface 11 a of the first transparent substrate 11 facing the second transparent substrate 12 . The transparent wall 15 is made of transparent resin or the like.
The transparent wall 15 is formed in a substantially rectangular parallelepiped shape. The transparent wall body 15 is provided so that the surface 15a facing the second transparent substrate 12 is close to the second transparent substrate 12 and a space is provided between the second transparent substrate 12 and the surface 15a. Two long-side end faces 15c on the long-side direction X side of the transparent wall 15 are in contact with the inner side surfaces 14c of the boundary walls 14C and 14D.
Of the two short side direction end faces 15d and 15e on the short side direction Y side of the transparent wall 15, the first short side direction end face 15d facing the boundary wall 14B is in contact with the inner side surface 14c of the boundary wall 14B. .
The other, second short-side end surface (side surface) 15e facing the boundary wall 14A is located at the position of the inner end portion 13c of the black matrix 13, i. It is provided at the boundary 13c of the transmissive region R2. As a result, the second short-side end surface 15e and the inner side surface 14c on the boundary wall 14A side face each other with a gap therebetween.

A rectangular parallelepiped projecting portion 16 is formed on the second short-side end face 15e of the transparent wall 15 so that the surface 15a on the side of the second transparent substrate 12 projects toward the boundary wall 14A. A protruding end face 16c, which is a tip end face of the protruding portion 16, is in contact with the inner side surface 14c of the boundary wall 14A.
The projecting portion 16 is formed only in the central portion in the long-side direction X of the second short-side end face 15e. Thus, a space is provided between both ends 16d of the projecting portion 16 in the long side direction X and the inner side surfaces 14c of the boundary walls 14C and 14D located on both sides of the boundary wall 14A.

With the configuration as described above, the transparent wall 15 is provided in the transmissive region R1 of the pixel element 10 over the entire transmissive region R1 when viewed from the thickness direction Z in plan view.
The projecting portion 16 is hidden by the black matrix 13 located on the boundary wall 14A side, and is provided so as to be located in the opaque region R2.

With the structures of the first transparent substrate 11, the second transparent substrate 12, the boundary wall 14, the transparent wall 15 and the partition 16 as described above, two transparent substrates 11 and 12 are formed between the first transparent substrate 11 and the second transparent substrate 12. Spaces S1 and S2 are formed.
The first space S1 includes the inner surface 12b of the second transparent substrate 12, the surface 15a of the transparent wall 15 and the projecting portion 16 (more precisely, the surface of the first electrode E1 described later) facing the inner surface 12b, and It is defined by the inner side surface 14c of each boundary wall 14 .
The second space S2 consists of a second end surface (side surface) 15e in the short side direction of the transparent wall 15, an inner side surface 14c of the boundary wall 14A facing the transparent wall 15, an inner side surface 14c of the boundary walls 14C and 14D, and an inner side surface 14c of the boundary walls 14C and 14D. It is demarcated by the surface on the 1 transparent substrate 11 side and the inner surface 11a of the first transparent substrate 11 (more precisely, the surface of the second electrode E2 described later).

FIG. 6 mainly shows the shapes of the first space S1 and the second space S2 of the pixel element 10 as a perspective view. As shown in this figure, each of the first space S1 and the second space S2 is formed in a plate shape, that is, in a rectangular parallelepiped shape with a thin thickness in one direction.
The first space S1 is provided so as to extend in the direction in which the second transparent substrate 12 extends, that is, in the long-side direction X and the short-side direction Y along the second transparent substrate 12 . In addition, the first space S1 is provided such that the long side S1a extends along the long side 10a of the rectangular pixel element 10 shown in FIG. A short side S1b and a thickness direction side S1c of the first space S1 are provided to extend in the short side direction Y and the thickness direction Z, respectively.
The second space S2 has a long side S2a and a short side S2b extending along the rectangular short side 10b of the pixel element 10, ie, the long side direction X, and the orthogonal direction, ie, the thickness direction Z, respectively. is provided in A side S2c in the thickness direction of the second space S2 is provided so as to extend in the short side direction Y. As shown in FIG. The length of the side S2c in the thickness direction is formed to be smaller than the width of the black matrix 13. As shown in FIG.
In this way, when the thickness direction Z is the vertical direction, the first space S1 is oriented horizontally and the second space S2 is oriented vertically. They are positioned so as to form an L shape with S1a and S2a interposed therebetween.

As already described, the second short-side end surface (side surface) 15e facing the boundary wall 14A is provided at the boundary 13c between the transmissive region R1 and the non-transmissive region R2. As a result, the first space S1 is formed in the transmissive region R1. In addition, the second space S2 is located in the opaque region R2 because the length of the side S2c in the thickness direction is smaller than the width of the black matrix 13 .
The first space S1 and the second space S2 are formed so that the length of each side is determined so that the volume is approximately the same.

Here, the projecting portion 16 is provided between the first space S1 and the second space S2 and functions as a partition 16 that partitions them.
As already explained, a space is provided between both ends 16d of the partition 16 in the long side direction X and the inner side surfaces 14c of the boundary walls 14C and 14D located on both sides of the boundary wall 14A. there is These spaces allow the first space S1 and the second space S2 to communicate with each other.
In this way, the partition 16 has two communication holes, the first communication hole H1 provided on the boundary wall 14C side and the second communication hole H2 provided on the opposite boundary wall 14D side. It has H1 and H2. The first space S1 and the second space S2 communicate with each other through these communication holes H1 and H2.

The first electrode E1 and the second electrode E2 are provided in each of the first space S1 and the second space S2.
The first electrode E1 is provided on the surface 15a of the transparent wall 15 and the partition 16. As shown in FIG. The first electrode E1 is provided so as to cover the surface 15a of the transparent wall 15 and the partition 16 on the boundary wall 14C side of the second communication hole H2 provided on the boundary wall 14D side. The first electrode E1 is similarly notched at the portion where the first communication hole H1 is formed.
The second electrode E2 is provided on the inner surface 11a of the first transparent substrate 11 between the second short-side end surface 15e of the transparent wall 15 and the inner side surface 14c of the boundary wall 14A. The second electrode E2 is provided to cover the inner surface 11a on the boundary wall 14C side of the second communication hole H2. A portion of the second electrode E2 that overlaps with the first communication hole H1 when viewed in plan from the thickness direction Z is notched in the same manner as the first electrode E1.
In this manner, the first electrode E1 and the second electrode E2 are provided so as to be biased toward one side H1 of the two communication holes H1 and H2.

The first electrode E1 is a transparent electrode made of, for example, indium tin oxide.
The first electrode E<b>1 and the second electrode E<b>2 are controlled to be on or off by, for example, the value of the voltage applied to the data line 7 .

Two kinds of fluids L1 and L2 are sealed in the first space S1 and the second space S2.
The fluid L1 is a polar fluid L1 having polarity. The polar fluid L1 is colored with the color desired to be displayed by the pixel element 10 in question.
The fluid L2 is a non-polar fluid L2 having no polarity. The non-polar fluid L2 is a transparent liquid, such as oil, that does not mix with the polar fluid L1.
In FIGS. 3, 4 and 5, the colored polar fluid L1 is shown with a pattern. Also, the transparent non-polar fluid L2 is shown so that the structure beyond it can be seen through.

The polar fluid L1 and the non-polar fluid L2 are sealed in the first space S1 and the second space S2 that are in communication with each other in approximately equal volumes. As already explained, the first space S1 and the second space S2 are formed to have approximately the same volume. Therefore, for example, when the first space S1 is filled with the polar fluid L1, the second space S2 is filled with the non-polar fluid L2. Conversely, when the first space S1 is filled with the non-polar fluid L2, the second space S2 is filled with the polar fluid L1.

Next, the action of the electrofluid display device 1 will be described with reference to FIGS. 1 to 6 and 7 to 10. FIG.
FIG. 7 is an explanatory diagram showing a state in which the first space S1 is filled with the polar fluid L1 and the second space S2 is filled with the non-polar fluid L2. FIG. 8 is an explanatory diagram showing a state in which the polar fluid L1 has started to move from the state shown in FIG. 7 to the second space S2. FIG. 9 is an explanatory diagram showing a state in which the second space S2 is filled with the polar fluid L1 and the first space S1 is filled with the non-polar fluid L2. FIG. 10 is an explanatory diagram showing a state in which the polar fluid L1 has started to move from the state shown in FIG. 9 to the first space S1. 7 to 10, (a) is a cross-sectional view taken along line GG in FIG. 6, and (b) is a cross-sectional view taken along line II in FIG.

In this description, as an initial state, a state in which the first space S1 is filled with the polar fluid L1 as shown in FIG. 7A is considered. In this case, as shown in FIG. 7(b), the second space S2 is filled with the non-polar fluid L2. The interface between the polar fluid L1 and the non-polar fluid L2 is located inside or near the first communication hole H1 and the second communication hole H2, for example. In this state, the first space S1 provided in the transmissive region R1 is filled with the colored polar fluid L1. The color of L1 is displayed so as to cover the entire pixel element 10 .

In this state, the first electrode E1 provided in the first space S1 is turned on, and the second electrode E2 provided in the second space S2 is turned off. Then, due to the electrowetting phenomenon, the electric field generated by the operation of the electrodes E1 and E2 changes the contact angle of the portion of the interface between the polar fluid L1 and the nonpolar fluid L2 that contacts the inner walls of the spaces S1 and S2. , the fluids L1 and L2 are easily moved. Here, since the fluid L1 has polarity, the polar fluid L1 tends to move to the side where the voltage is weaker, that is, to the second space S2 where the second electrode E2 is located. As already explained, since the electrodes E1 and E2 are provided biased toward the first communication hole H1, the polar fluid L1 passes through the first communication hole H1 and is shown as arrows R1 and R2 in FIG. to the second space S2.

Due to the movement of the polar fluid L1 to the second space S2, the non-polar fluid L2 filling the second space S2 is pushed out of the second space S2, and is opposite to the first communication hole H1 through which the polar fluid L1 passes. It passes through the second communication hole H2 on the side and moves to the first space S1 so as to replace the polar fluid L1 as indicated by arrows R3 and R4.

When the state of FIG. 9 in which the polar fluid L1 has completely moved to the second space S2 is reached, the movement of the polar fluid L1 and the non-polar fluid L2 stops.
In the state shown in FIG. 9, the first space S1 provided in the transmissive region R1 is filled with a transparent non-polar fluid L2. The first transparent substrate 11, the second transparent substrate 12, the transparent wall 15, and the first electrode E1, which constitute the transmissive region R1, are each made of a transparent material. Therefore, for example, when the pixel element 10 is viewed from outside the second transparent substrate 12 , it is displayed so as to be transmitted to the opposite side of the first transparent substrate 11 .

In the state shown in FIG. 9, the first electrode E1 provided in the first space S1 is turned off, and the second electrode E2 provided in the second space S2 is turned on. Then, the electrowetting phenomenon causes the fluids L1 and L2 to move easily, and the polar fluid L1 tries to move to the first space S1 where the first electrode E1 is located. Since the electrodes E1 and E2 are biased toward the first communication hole H1, the polar fluid L1 passes through the first communication hole H1 and flows through the first communication hole H1 as indicated by arrows R5 and R6 in FIG. Move to space S1.
Due to the movement of the polar fluid L1 to the first space S1, the non-polar fluid L2 filling the first space S1 is pushed out from the first space S1, passes through the second communication hole H2, and is shown by arrows R7 and R8. , moves to the second space S2 so as to replace the polar fluid L1.
When the polar fluid L1 has completely moved into the first space S1, as shown in FIG. 7, the movement of the polar fluid L1 and the non-polar fluid L2 stops.

In the above, for ease of explanation, when the fluids L1 and L2 move from the state shown in FIG. 7 to the state shown in FIG. It has been explained not to stop moving until the spaces S1 and S2 are filled. However, in practice, by appropriately adjusting the voltages applied to the electrodes E1 and E2, for example, an arbitrary proportion of the first space S1 is filled with the polar fluid L1 and the rest is filled with the non-polar fluid L2. can also be balanced. In this manner, the electrofluid display device 1 can display arbitrary gradations.

Next, setting of sizes of the first space S1 and the second space S2 will be described.
As already described, the first space S1 and the second space S2 are formed to have approximately the same volume. Therefore, the lengths of the long side S1a, the short side S1b, and the side S1c in the thickness direction of the first space S1 shown in FIG. The electrofluid display device 1 according to the present embodiment can be realized by forming the lengths of the directional sides S2c to be substantially equal to each other.

However, in practice, the length of the side S2c in the thickness direction of the second space S2 is restricted by the width of the black matrix 13, and therefore has to be shorter than the length of the side S1c in the thickness direction of the first space S1. may not be obtained. In this embodiment, as shown in FIG. 6 and the like, the length of the long side S1a of the first space S1 and the length of the long side S2a of the second space S2 are substantially the same. Therefore, if the length of the side S2c in the thickness direction of the second space S2 is made shorter than the length of the side S1c in the thickness direction of the first space S1, the volumes of the first space S1 and the second space S2 are substantially equal. , the length of the short side S2b of the second space S2 must be longer than the length of the short side S1b of the first space S1.
In such a case, the length of the short side S2b of the second space S2 is obtained by multiplying the length of the short side S1b of the first space S1 by the length of the side S1c in the thickness direction. It can be derived by dividing by the length of the desired thickness side S2c of the second space S2, such as the width.

In addition, in this embodiment, the electrofluid display device 1 is capable of color display as described with reference to FIG. However, it is also conceivable to combine an electrofluidic display device with an existing transmissive display device and use it as a composite display device, as will be described later as a second embodiment, for example. In this case, the composite display device can be used as a transmissive display device by displaying the electrofluidic display device in a transmissive state. Furthermore, in some cases, the electrofluidic display device can be placed in an opaque state so that the composite display device can be used as a single-sided viewable display device.
Thus, when used in combination with a transmissive display device, the electrofluidic display device, when used in an opaque state, covers the entire surface of the transmissive display device with a single color, such as black, or a single tone. should be displayed as In other words, in this case, the only function required of the electrofluid display device is switching between a transparent state and an opaque state in which a single color is displayed on the entire surface.
Theoretically, therefore, a composite display device can be realized by preparing an electrofluid display device having one pixel element 10 having an area equivalent to that of the transmissive display device and stacking it on the transmissive display device. is possible.

However, in this case, the length of the pixel element 10 in the thickness direction Z must be equal to the width of the transmissive display device, which makes the electrofluid display device large and difficult to manufacture.
In addition, since the electrofluidic display device switches the display by moving the fluids L1 and L2, it takes time to move the fluids L1 and L2 when the pixel element 10 becomes large, and the response speed when switching the display is desirable. becomes nothing.
In other words, the pixel element 10 that is too large as described above is not practical, and the pixel element 10 must be formed in an appropriate size in order for the electrofluid display device 1 to exhibit appropriate performance.

For example, as an example, the length of the long side S1a of the first space S1 is 115 μm, the length of the short side S1b is 35 μm, and the length of the side S2c in the thickness direction of the second space S2 is 10 μm. Thus, an electrofluid display device 1 having sufficient response speed and high resolution can be realized.

Also, for example, the length of the side S1c in the thickness direction of the first space S1 can be determined by the concentration of the colored polar fluid L1. That is, since there is an upper limit to the concentration of the dye that can be dissolved in the fluid L1, it is necessary to lengthen the side S1c in the thickness direction in order to increase the shielding performance during opaque display, which is desired to be realized in the electrofluid display device 1. be.

Next, the effect of the electrofluid display device 1 will be described.

In the electrofluid display device 1 of the present embodiment, pixel elements 10 are provided on first and second transparent substrates 11 and 12 facing each other, and at least one of the first and second transparent substrates 11 and 12. 12, a black matrix 13 provided at the boundary 14d of the pixel element 10 to form an opaque region R2 that does not transmit light, and a black matrix 13 formed between the first and second transparent substrates 11, 12 and communicating with each other. First and second spaces S1, S2, a polar fluid L1 and a non-polar fluid L2 sealed in the first and second spaces S1, S2, one colored and the other transparent, and the first and second The electrofluid display device 1 includes first and second electrodes E1 and E2 provided in spaces S1 and S2, respectively. The two spaces S2 are formed in the opaque region R2.
According to the configuration as described above, both the first and second substrates 11 and 12 are transparent substrates, and the first space S1 transmits light through the first and second transparent substrates 11 and 12. The first space S1 is visible from the outside because it is provided in the transmissive region R1. Also, the second space S2 is formed in an opaque region R2 formed by the black matrix 13 and through which light does not pass. Therefore, by applying a voltage to the first and second electrodes E1 and E2, for example, the colored fluid L1 is formed in the second space S2 and the transparent fluid L2 is formed in the transmissive region R1 in the first space S1. , respectively. In this case, the light transmitted through one substrate 12 from the outside in the transmissive region R1 and entering the inside of the pixel element 10 reaches the other substrate 11 after passing through the transparent fluid L1 that fills the first space S1. ,To Penetrate. Further, since the colored fluid L1 is hidden in the non-transmissive region R2 by the black matrix 13, it does not block the light entering the transmissive region R1. Thereby, an electrofluid display device 1 with high transparency can be realized.

A partition 16 is provided between the first and second spaces S1 and S2 to partition the first and second spaces S1 and S2. The partition 16 has two communication holes H1 and H2. and the second spaces S1 and S2 are communicated by two communication holes H1 and H2, and the first and second electrodes E1 and E2 are biased toward one H1 side of the two communication holes H1 and H2. .
According to the configuration as described above, the first and second spaces S1 and S2 are communicated by the two communication holes H1 and H2, and the electrodes E1 and E2 are connected to one H1 side of the two communication holes H1 and H2. is biased toward Therefore, for example, when one space is filled with a polar fluid L1 and the other space is filled with a non-polar fluid L2, by appropriately applying a voltage to the electrodes E1 and E2, the electrodes E1 and E2 are The polar fluid L1 can be passed to the other space through the communication hole H1 on the side provided unevenly. The nonpolar fluid L2 filled in the other space passes through the other communication hole H2 so as to be pushed out by the polar fluid L1 that has flowed into the other space. move to In this way, since the movement of each fluid L1, L2 can be easily controlled, gradation can be expressed appropriately.

A transparent wall 15 is provided in the transmissive region R1 of the first transparent substrate 11 so that the surface 15a is close to the second transparent substrate 12, and the first space S1 is separated from the surface 15a of the transparent wall 15. It is formed between the second transparent substrates 12 .
According to the configuration as described above, the thickness of the first space S1 in the direction Z orthogonal to the substrates 11 and 12 is reduced regardless of the distance between the first transparent substrate 11 and the second transparent substrate 12. , can form a transmissive region R1. By thinning the first space S1 in this manner, the volume of the first space S1 can be reduced, and the amounts of the fluids L1 and L2 sealed in the spaces S1 and S2 can be reduced. That is, since the amount of the fluids L1 and L2 to be moved when the voltage is applied to the electrodes E1 and E2 is reduced, the reaction becomes faster and the image display speed can be improved.

In addition, the pixel element 10 includes a boundary wall 14 that separates the pixel element 10 from the outside at the boundary of the pixel element 10, and the side surface 15e of the transparent wall 15 is provided at the boundary between the transmissive region R1 and the non-transmissive region R2, A second space S2 is defined by the side surface 15e of the transparent wall 15 and the boundary wall .
According to the configuration as described above, the second space S2 is defined by the side surface 15e of the transparent wall 15 provided at the boundary between the transmissive region R1 and the non-transmissive region R2. It is formed in the opaque region R2. Thereby, the transmittance of the electrofluid display device 1 is improved.

In addition, the pixel element 10 is formed in a rectangular parallelepiped shape, and has a rectangular shape when viewed in plan from the orthogonal direction Z orthogonal to the first transparent substrate 11, and the black matrix 13 is provided along at least the long side 10a of the rectangular shape. The first space S1 is formed in a plate-like shape, extending along the second transparent substrate 12 in the directions X and Y in which the second transparent substrate 12 extends, and the long side S1a of the first space S1. is provided to extend along the long side 10a of the rectangular shape, the second space S2 is also formed in a plate shape, and each of the long side S2a and the short side S2b of the second space S2 is formed by the long side of the rectangular shape They are provided so as to extend along the direction Z orthogonal to 10a.
According to the above configuration, the first space S1 can be formed to have substantially the same shape and substantially the same size as the transmissive region R1 of the pixel element 10 .
Further, the sides of the plate-like second space S2 extending in the orthogonal direction Z orthogonal to the substrates 11 and 12 are short sides S2b. For example, when the side extending in the orthogonal direction Z is the long side S2a, the distance between the first and second substrates 11 and 12 may have to be unreasonably large. Further, for example, when the side extending in the orthogonal direction Z is the side S2c in the thickness direction, both the long side S2a and the short side S2b are positioned parallel to the substrates 11 and 12, so that each substrate 11 , 12, the area of the second space S2 becomes unduly large, resulting in a decrease in transmittance. By setting the side extending in the orthogonal direction Z to the short side direction S2b as in the above configuration, the distance between the substrates 11 and 12 is maintained at an appropriate distance to facilitate manufacturing, and the substrates 11 and 12 can be easily manufactured. The area of the second space S2 on the substrates 11 and 12 can be reduced and the transmittance can be increased by setting the long side S2a and the side S2c in the thickness direction to be parallel to the substrate 12 .

Also, the length of the side of the second space S2 in the thickness direction S2c is smaller than the width of the black matrix 13 .
With the configuration as described above, it is possible to reliably hide the second space S2 in the non-transmissive region R2 formed by the black matrix 13 . Thereby, the transmittance of the electrofluid display device 1 is improved.

The electrofluid display device 1 also includes a plurality of pixels 8, each pixel 8 having a first, second, and third sub-pixel in which one of the polar fluid L1 and the non-polar fluid L2 is different from each other. It comprises first, second and third pixel elements 10R, 10G, 10B colored with colors.
According to the configuration as described above, one pixel 8 of the electrofluid display 1 can be realized by a plurality of pixel elements 10R, 10G, and 10B sealed with fluids L1 colored in different colors. It is possible to display colors by variously combining different colors of .

[Second embodiment]
Next, a second embodiment will be described. FIG. 11 is a schematic exploded perspective view of the composite display device according to the second embodiment.
A composite display device 30 according to the second embodiment includes the electrofluid display device 31 as described in the first embodiment, and a transparent display device 40 . In this embodiment, the electrofluid display device 31 is used as a dimming panel.

The transparent display device 40 is a display, such as a transparent organic EL display, which performs transmissive display in a portion where no image is displayed.
A transparent display device 40 comprises a plurality of pixels 41 . Each of the plurality of pixels 41 includes, for example, a first sub-pixel 42R displaying red, a second sub-pixel 42G displaying green, and a third sub-pixel 42B displaying blue.

The electrofluid display device 31 comprises a plurality of pixel elements 32, as in the first embodiment. The pixel element 32 in this embodiment differs from the pixel element 10 in the first embodiment in that the polar fluid L1 of all the pixel elements 32 is colored with a single color suitable for light blocking, such as black. there is
Also, the pixel element 32 in this embodiment is driven by a passive matrix.
Otherwise, pixel element 32 is structurally configured similarly to pixel element 10 .
Electrofluidic display device 31 comprises the same number of pixel elements 32 as sub-pixels 42 R, 42 G, 42 B of transparent display device 40 .

The electrofluidic display device 31 and the transparent display device 40 are stacked so as to be in close contact with each other. Each pixel element 32 of the electrofluid display device 31 corresponds to a sub-pixel 42R, 42R, 42R of the transparent display device 40 when the composite display device 30 in which the electrofluid display device 31 and the transparent display device 40 are stacked in this way is viewed from above. 42G and 42B are provided so as to be positioned on the same plane.

Thus, the composite display device 30 in this embodiment comprises an electrofluid display device 31 and a transparent display device 40, wherein the electrofluid display device 31 and the transparent display device 40 are composed of the pixel elements 32 of the electrofluid display device 31, Sub-pixels 42R, 42G, and 42B, which constitute each pixel 41 of the transparent display device 40, are overlapped so as to correspond to each other.
According to the above configuration, for example, in all the pixel elements 32 of the electrofluid display device 31, the colored fluid L1 is moved to the second space S2 side as described in the first embodiment, and the electrofluid display is displayed. Composite display device 30 can be used as a transparent display device by placing device 31 in a transmissive state. In this case, the composite display device 30 can be suitably used for digital signage, for example. In addition, in all the pixel elements 32, by moving the colored fluid L1 to the first space S1 side to put the electrofluid display device 31 in an opaque state, that is, a light-shielding state, the composite display device 30 becomes an opaque type. It can be used as a display device. In this case, the composite display device 30 can be used for digital signage as described above, and it is also possible to display and view images as a normal display, for example.
Thus, the usability of the transparent display device 40 overlaid on the electrofluidic display device 31 is improved.

Also, the polar fluid L1 of the electrofluid display device 31 is colored black.
The configuration as described above is suitable when the composite display device 30 is used as an opaque display device.

Also, the pixel elements 32 of the electrofluid display device 31 are driven by a passive matrix.
According to the configuration as described above, manufacturing of the electrofluid display device 31 is facilitated, and the manufacturing cost can be reduced.

[Modification of Second Embodiment]
Next, a modification of the composite display device 30 shown as the second embodiment will be described with reference to FIG. FIG. 12 is a schematic exploded perspective view of a composite display device according to this modification. The transparent display device 50 in this modified example differs from the composite display device 30 shown as the second embodiment in that the electrofluidic display device 31 is superimposed on both surfaces of the transparent display device 40 . ing.

According to the configuration as described above, the composite display device 50 can be used as a transparent display device, for example, by setting both of the electrofluidic display devices 31 in a transmissive state. In addition, since the electrofluid display devices 31 are provided on both surfaces of the transparent display device 50, by making an arbitrary electrofluid display device 31 in an opaque state and the other in a transmissive state, the transparent display device 50 can be The displayed image can be displayed and visible only in an arbitrary direction. Therefore, the usability of the transparent display device 40 overlaid on the electrofluid display device 31 is improved.

It goes without saying that this modified example has other effects similar to those of the already described second embodiment.

It should be noted that the electrofluid display device and composite display device of the present invention are not limited to the above-described embodiments and modifications described with reference to the drawings, and various modifications are possible within the technical scope thereof. can be considered.

For example, although the black matrix 13 is provided on the second transparent substrate 12 side in each of the above-described embodiments and modifications, it may be provided on the first transparent substrate 11 side.
Further, in each of the above-described embodiments and modifications, the polar fluid L1 is colored, but the non-polar fluid L2 may be colored.

In addition to this, it is possible to select the configurations mentioned in each of the above-described embodiments and modifications, or to change them to other configurations as appropriate without departing from the gist of the present invention.

1, 31 electrofluid display device 8 pixel 10, 32 pixel element 10R first pixel element 10G second pixel element 10B third pixel element 10a long side 10b short side 11 first transparent substrate 12 second transparent substrate 13 black matrix 13c inside edge of (the boundary between transparent and opaque areas)
14 Boundary wall 14d Outer side (boundary of pixel elements)
15 transparent wall (transparent wall)
15a surface 15e second short side end surface (side surface)
16 protrusion (partition)
30, 50 composite display device 40 transparent display device 42R first sub-pixel (sub-pixel)
42G second sub-pixel (sub-pixel)
42B third sub-pixel (sub-pixel)
Long side direction of X pixel element (direction in which the second transparent substrate extends)
Short side direction of Y pixel element (direction in which the second transparent substrate extends)
Z pixel element thickness direction (perpendicular direction)
R1 Transmissive region R2 Non-transmissive region S1 First space S1a Long side S1b Short side S1c Side in thickness direction S2 Second space S2a Long side S2b Short side S2c Side in thickness direction L1 Polar fluid L2 Non-polar fluid E1 First electrode E2 Second electrode H1 First communication hole (connection hole, one side)
H2 second communication hole (communication hole)

Claims (9)

A pixel element is
first and second transparent substrates facing each other;
a black matrix provided on at least one of the first and second transparent substrates at a boundary between the pixel elements and forming an opaque region that does not transmit light;
first and second spaces communicating with each other formed between the first and second transparent substrates;
a polar fluid and a non-polar fluid, one colored and the other transparent, sealed in the first and second spaces;
first and second electrodes respectively provided in the first and second spaces;
An electrofluid display device comprising:
The first space is formed in a transmissive region that transmits light, the second space is formed in the non-transmissive region ,
A partition for partitioning the first and second spaces is provided between the first and second spaces,
The partition has two communicating holes, and the first and second spaces communicate with each other through the two communicating holes,
The electrofluidic display device, wherein the first and second electrodes are biased toward one side of the two communication holes . A pixel element is
first and second transparent substrates facing each other;
a black matrix provided on at least one of the first and second transparent substrates at a boundary between the pixel elements and forming an opaque region that does not transmit light;
first and second spaces communicating with each other formed between the first and second transparent substrates;
a polar fluid and a non-polar fluid, one colored and the other transparent, sealed in the first and second spaces;
first and second electrodes respectively provided in the first and second spaces;
An electrofluid display device comprising:
The first space is formed in a transmissive region that transmits light, the second space is formed in the non-transmissive region,
A transparent wall is provided in the transmissive region of the first transparent substrate so that the surface approaches the second transparent substrate,
The electrofluidic display device, wherein the first space is formed between the surface of the transparent wall and the second transparent substrate. the pixel element comprises a boundary wall that partitions the pixel element from the outside at the boundary of the pixel element;
The side surface of the transparent wall is provided at the boundary between the transmissive area and the non-transmissive area,
3. The electrofluid display device according to claim 2 , wherein the second space is defined by the side surface of the transparent wall and the boundary wall. A pixel element is
first and second transparent substrates facing each other;
a black matrix provided on at least one of the first and second transparent substrates at a boundary between the pixel elements and forming an opaque region that does not transmit light;
first and second spaces communicating with each other formed between the first and second transparent substrates;
a polar fluid and a non-polar fluid, one colored and the other transparent, sealed in the first and second spaces;
first and second electrodes respectively provided in the first and second spaces;
An electrofluid display device comprising:
The first space is formed in a transmissive region that transmits light, the second space is formed in the non-transmissive region,
The pixel element is formed in a rectangular parallelepiped shape, and has a rectangular shape when viewed from above in a direction orthogonal to the first transparent substrate,
The black matrix is provided along at least a long side of the rectangular shape,
The first space is formed in a plate shape and extends along the second transparent substrate in the direction in which the second transparent substrate extends, and the long side of the first space is the length of the rectangular shape. provided to extend along the side,
The second space is also formed in a plate shape, and each of the long sides and short sides of the second space extends along the long side of the rectangular shape and the orthogonal direction, respectively. pneumatic display device. 5. The electrofluid display device of claim 4 , wherein the length of a side of the second space in the thickness direction is smaller than the width of the black matrix. with multiple pixels,
each pixel, as a sub-pixel, one of said polar fluid and said non-polar fluid is colored with first, second and third colors different from each other; 6. An electrofluidic display device according to any one of the preceding claims, comprising pixel elements. an electrofluid display device according to any one of claims 1 to 5 ;
a transparent display device;
with
The electrofluid display device and the transparent display device are stacked such that the pixel elements of the electrofluid display device correspond to the sub-pixels forming the pixels of the transparent display device. , a composite display device. 8. The composite display device of claim 7 , wherein one of said polar fluid and said non-polar fluid of said electrofluidic display device is colored black. 9. A composite display device according to claim 7 or 8 , wherein the electrofluidic display device is provided over both surfaces of the transparent display device.

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