Patent Application
20220171250
The embodiment of the present invention relates to a display device.
As an example of a display device, an electrophoretic display device has been proposed in which an electrophoretic element is sandwiched between an element substrate and a counter-substrate. In this type of electrophoretic display device, a peripheral circuit or the like is provided in a non-display area around a display area, and a frame that does not contribute to display is formed. In recent years, there has been a demand for a larger screen of a display device. In response to such a demand, a tiling technique for coupling a plurality of display devices is known.
In general, according to one embodiment, a display device comprises: a first drive substrate comprising a first base having a first end portion, a plurality of first pixel electrodes arranged along the first end portion, and a first drive circuit provided between the plurality of first pixel electrodes and the first end portion; a second drive substrate that is separate from the first drive substrate and comprises a second base having a second end portion in contact with the first end portion, a plurality of second pixel electrodes arranged along the second end portion, and a second drive circuit provided between the plurality of second pixel electrodes and the second end portion; and a counter-substrate comprising a support base opposed to the first drive substrate and the second drive substrate, and an electrophoretic layer provided between the first drive substrate and the support base and between the second drive substrate and the support base, wherein the first end portion of the first base and the second end portion of the second base are in contact with each other to form a contact portion, and the electrophoretic layer overlaps the plurality of first pixel electrodes, the first drive circuit, the contact portion, the second drive circuit, and the plurality of second pixel electrodes.
According to one embodiment, it is possible to provide a display device capable of achieving a large screen.
Embodiments will be described hereinafter with reference to the accompanying drawings. The disclosure is merely an example, and proper changes within the spirit of the invention, which are easily conceivable by a skilled person, are included in the scope of the invention as a matter of course. In addition, in some cases, in order to make the description clearer, the widths, thicknesses, shapes, etc., of the respective parts are schematically illustrated in the drawings, compared to the actual modes. However, the schematic illustration is merely an example, and adds no restrictions to the interpretation of the invention. Besides, in the specification and drawings, the same or similar elements as or to those described in connection with preceding drawings or those exhibiting similar functions are denoted by like reference numerals, and a detailed description thereof is omitted unless otherwise necessary.
In the display device DSP, the drive substrate 1 is provided on the back side of the counter-substrate 2, and the counter-substrate 2 is provided on a display surface side. The drive substrate 1 may be referred to as a backplane, and the counter-substrate 2 may be referred to as a front plane.
Each of the drive substrates 1A, 1B, and 1C is formed in a rectangular shape extending in the first direction X. The drive substrates 1A, 1B, and 1C are arranged in the first direction X and are in contact with each other. In other words, the drive substrates 1A and 1B form a contact portion AB with which their shorter sides opposed to each other in the first direction X are in contact. In addition, the drive substrates 1B and 1C form a contact portion BC with which their shorter sides opposed to each other in the first direction X are in contact. Incidentally, the term “contact” between the substrates here includes not only a state in which the substrates abut on each other but also a state in which the substrates are opposed to each other with a slight gap interposed therebetween and are provided close to each other to such an extent that the gap can be ignored in terms of structure.
The drive substrates 1A, 1B, and 1C have active areas 3A, 3B, and 3C, respectively. Each of the active areas 3A, 3B, and 3C is formed in a rectangular shape extending in the first direction X. The active areas 3A, 3B, and 3C correspond to areas surrounded by dash-dotted lines in the drawing.
In the drive substrates 1A and 1B, a sub-area 4AB across the contact portion AB is provided between the active areas 3A and 3B arranged in the first direction X. In addition, in the drive substrates 1B and 1C, a sub-area 4BC across the contact portion BC is provided between the active areas 3B and 3C arranged in the first direction X. The sub-areas 4AB and 4BC correspond to areas indicated by hatching in the drawing.
The counter-substrate 2 is formed in a rectangular shape extending in the first direction X. With respect to the length along the first direction X, the counter-substrate 2 is longer than one drive substrate 1. In the example illustrated in
The moisture-proof material 5 includes a first part 51 and a second part 52. The first part 51 covers the entire circumference of a side surface 2S of the counter-substrate 2. In addition, the first part 51 is formed in a frame shape in planar view and intersects the contact portions AB and BC. The second part 52 covers the contact portions AB and BC, respectively. In other words, the second part 52 is provided on each of an upper surface (in particular, a part where the counter-substrate 2 does not overlap) 1U, a lower surface 1L, and a side surface 1S of each drive substrate 1. The second part 52 is in communication with the first part 51 at an intersection with the contact portion AB and an intersection with the contact portion BC in the first part 51. Such moisture-proof material 5 is formed of a material that prevents ingress of moisture or the like into an adhesive layer or an electrophoretic layer described later.
The bases 10A and 10B are insulating substrates formed of the same material, for example, glass or synthetic resin. The base 10A has end portions 101A and 102A along the first direction X. The base 10B has an end portion 102B along the first direction X. The end portion 101A and the end portion 102B are in contact with each other to form a contact portion AB.
In the drive substrate 1A, the active area 3A includes a plurality of pixels PXA. In each pixel PXA, the pixel electrode 14A is electrically connected to the switching element 13A. The pixel electrode 14A is located on an insulating film IA. The drive circuit 11A is provided between the pixel electrode 14A located at the outermost periphery of the active area 3A and the end portion 101A in the first direction X. The drive circuit 11A is covered with the insulating film IA.
In the drive substrate 1B, the active area 3B includes a plurality of pixels PXB. In each pixel PXB, the pixel electrode 14B is electrically connected to the switching element 13B. The pixel electrode 14B is located on an insulating film IB. The drive circuit 12B is provided between the pixel electrode 14B located at the outermost periphery of the active area 3B and the end portion 102B in the first direction X. The drive circuit 12B is covered with the insulating film IB.
The drive circuits 11A and 12B are located between the active areas 3A and 3B adjacent to each other or in the sub-area 4AB. The drive circuit 11A described here includes a control circuit necessary for driving each pixel PXA in the active area 3A, and includes, for example, a gate driver for controlling on/off of the switching element 13A, but may include another circuit such as a source driver for supplying the pixel electrode 14A with a pixel potential. The drive circuit 12B is also configured in the same manner as the drive circuit 11A.
The counter-substrate 2 includes a support base 20, a common electrode 21, an electrophoretic layer 22, a base 23, and the like. The support base 20 is opposed to the drive substrates 1A and 1B in the third direction Z. The electrophoretic layer 22 is provided between the drive substrate 1A and the support base 20 and between the drive substrate 1B and the support base 20. In addition, the electrophoretic layer 22 overlaps the contact portion AB and the drive circuits 11A and 12B. The common electrode 21 is provided between the support base 20 and the electrophoretic layer 22. The common electrode 21 and the electrophoretic layer 22 are held between the support base 20 and the base 23. The support base 20, the common electrode 21, and the base 23 continuously extend without interruption at a position overlapping the contact portion AB.
The electrophoretic layer 22 includes a plurality of microcapsules 30 dispersedly disposed between the support base 20 and the base 23. Each microcapsule 30 includes an outer shell 31, a plurality of black particles 32, a plurality of white particles 33, and a dispersion medium 34. The black particles 32, the white particles 33, and the dispersion medium 34 are accommodated in the outer shell 31. The black particles 32 and the white particles 33 may also be referred to as electrophoretic particles. The outer shell 31 is formed of, for example, a transparent resin such as an acrylic resin. The dispersion medium 34 is a liquid that disperses the black particles 32 and the white particles 33 in the outer shell 31. Incidentally, in addition to the black particles 32 and the white particles 33, the microcapsules 30 may include electrophoretic particles of other colors such as red, green, blue, yellow, cyan, and magenta. In addition, the above-mentioned electrophoretic particles of other colors may be replaced with at least one of the black particles 32 and the white particles 33.
At least one of the plurality of microcapsules 30 overlaps the contact portion AB and the drive circuits 11A and 12B.
In addition, in the example illustrated in
The support base 20 and the bases 23 and 24 are transparent insulating substrates formed of, for example, glass or synthetic resin. The common electrode 21 is a transparent electrode. The barrier layer 25 is a transparent inorganic insulating film. The bonding layer 26 is transparent.
A conductive adhesive layer 40 is provided between the drive substrate 1A and the counter-substrate 2 and between the drive substrate 1B and the counter-substrate 2 over substantially the entire surface. The base 23 of the counter-substrate 2 is stuck to the drive substrates 1A and 1B with the adhesive layer 40.
The first part 51 of the moisture-proof material 5 covers the side surface 2S of the counter-substrate 2 on the drive substrate 1A. That is, the first part 51 is in contact with the end portions of the support base 20, the common electrode 21, the electrophoretic layer 22, the base 23, the base 24, the barrier layer 25, and the bonding layer 26. The first part 51 is also in contact with the end portion of the adhesive layer 40. The second part 52 of the moisture-proof material 5 covers the contact portion AB.
Though not illustrated in
In the example illustrated in
The drive substrate 1A further includes insulating films I11 to I14, a power supply line FL, and a capacitive electrode CE, in addition to the drive circuit 11A, the switching element 13A, and the pixel electrode 14A. The insulating films I11 to I14 are included in the insulating film IA illustrated in
The gate electrode GE electrically connected to a scanning line GL is located on the base 10A and is covered with the insulating film I11. The semiconductor layer SC is located on the insulating film I11 and is covered with the insulating film I12. The semiconductor layer SC is formed of, for example, polycrystalline silicon (e.g., low temperature polysilicon), but may be formed of amorphous silicon or an oxide semiconductor. The power supply line FL, a signal line SL, and the drain electrode DE are located on the insulating film I12 and are covered with the insulating film I13. The signal line SL is in contact with the semiconductor layer SC in a through hole CH1 penetrating the insulating film I12. The drain electrode DE is in contact with the semiconductor layer SC in a through hole CH2 penetrating the insulating film I12.
The drive circuit 11A includes a plurality of thin-film transistors, but detailed illustration thereof is omitted. The drive circuit 11A is covered with the insulating film I13.
The capacitive electrode CE is located on the insulating film I13 and is covered with the insulating film I14. The capacitive electrode CE is in contact with the power supply line FL in a through hole CH5 penetrating the insulating film I13.
The pixel electrode 14A is located on the insulating film I14. The pixel electrode 14A is in contact with the drain electrode DE in a through hole CH3 penetrating the insulating film I13 and a through hole CH4 penetrating the insulating film I14. The pixel electrode 14A overlaps the capacitive electrode CE with the insulating film I14 interposed therebetween to form a capacitance Cl of the pixel PXA.
The insulating films I11, I12, and I14 are, for example, inorganic insulating films. The insulating film I13 is, for example, one or more organic insulating films. The capacitive electrode CE and the pixel electrode 14A are transparent electrodes formed of, for example, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The pixel electrode 14A or the capacitive electrode CE may include a reflecting electrode (metal electrode). Alternatively, in each pixel PXA, a reflecting electrode may be provided between the base 10A and the electrophoretic layer 22.
In the counter-substrate 2, the common electrode 21 and the electrophoretic layer 22 are disposed so as to overlap the drive circuit 11A. The common electrode 21 has the same electric potential as the capacitive electrode CE. In the microcapsules 30, the black particles 32 and the white particles 33 are charged in opposite polarities with each other. For example, the black particles 32 are positively charged and the white particles 33 are negatively charged.
In the display device DSP having the above configuration, when the pixel PXA displays black, the pixel electrode 14A is held at a relatively higher electric potential than the common electrode 21. That is, when the electric potential of the common electrode 21 is set as a reference potential, the pixel electrode 14A is held in positive polarity. Therefore, positively charged black particles 32 are attracted to the common electrode 21, while negatively charged white particles 33 are attracted to the pixel electrode 14A. As a result, when the pixel PXA is observed from above the counter-substrate 2, black is visually recognized.
In contrast, when the pixel PXA displays white, the pixel electrode 14A is held at a relatively lower electric potential than the common electrode 21. That is, when the electric potential of the common electrode 21 is set as a reference potential, the pixel electrode 14A is held in negative polarity. Therefore, negatively charged white particles 33 are attracted toward the common electrode 21 side, while positively charged black particles 32 are attracted to the pixel electrode 14A. As a result, when the pixel PXA is observed, white is visually recognized.
In the sub-area 4AB where the drive circuit 11A is provided, no pixel electrode is provided directly above the drive circuit 11A. However, as described above, the common electrode 21 and the electrophoretic layer 22 are provided directly above the drive circuit 11A. For this reason, when the pixel PXA located at the outermost periphery of the active area 3A is driven, the pixel electrode 14A is supplied with a pixel potential, so that an electric field is formed in the pixel PXA, and the electric field also spreads directly above the drive circuit 11A. In other words, in both the pixel PXA and the sub-area 4AB, an electric field is formed between the pixel electrode 14A and the common electrode 21. In other words, the pixel electrode 14A is provided along the boundary between the active area 3A and the sub-area 4AB, and as a result, the electric field generated by the pixel electrode 14A spreads not only to the active area 3A but also to a part of the sub-area 4AB. In addition, the width of the sub-area 4AB is significantly narrow, and the width thereof is only enough to dispose the drive circuit 11A. For this reason, the electrophoretic layer 22 directly above the drive circuit 11A is driven, and the same color is visually recognized in the pixel PXA and the sub-area 4AB. In short, a display area DA is formed not only in an area overlapping the active area 3A but also in an area overlapping the sub-area 4AB. The electric field of the pixel located at the outermost periphery of the active area also similarly spreads directly above the other drive circuits or in the other sub-area, and the electrophoretic layer 22 is driven as well as the outermost peripheral pixel. Therefore, an image can be displayed over a wider range than the active area of each drive substrate, and the image can also be displayed at contact portions between adjacent drive substrates. This allows a display area DA in which joints are hardly visually recognized to be formed.
Next, a display device according to another embodiment will be described. In other embodiments described below, the same components as those of the display device in the first embodiment described above are denoted by the same reference numerals as those in the first embodiment, and a detailed description thereof may be simplified or omitted. Parts different from those of the first embodiment will be mainly described in detail.
A flexible printed circuit board FA is connected to a drive substrate 1A. A flexible printed circuit board FB is connected to a drive substrate 1B. The conductive layer 50 is interposed between the flexible printed circuit board FA and the flexible printed circuit board FB. In the example illustrated in
The power line PL is, for example, a first power line having an electric potential for black display or a second power line having an electric potential for white display. In the example illustrated in
According to the second embodiment, by supplying the conductive layer 50 with a predetermined electric potential equal to the pixel potential, an electric field is formed between the conductive layer 50 and a common electrode 21. As a result, the electrophoretic layer 22 overlapping the contact portion AB, the drive circuit 11A, and the drive circuit 12B is driven. Therefore, a display area DA is formed over an active area 3A, the sub-area 4AB, and an active area 3B.
Incidentally, in the second embodiment, since the electrophoretic layer 22 of the sub-area 4AB is driven by a single conductive layer 50, the same display is performed over the sub-area 4AB. In addition, since the conductive layer 50 is formed in a strip shape extending in the second direction Y, it is suitable for displaying a vertical line (partition line) extending in the second direction Y between the active area 3A and the active area 3B or displaying a solid pattern having the same color as the display colors of the outermost peripheries of the active areas 3A and 3B.
In the example illustrated in
Either one of the first electrode 61 or the second electrode 62 is electrically connected to a power line PL as illustrated in
The first electrode 61 and the second electrode 62 extend along the contact portion AB, and are each formed in a strip shape extending in the second direction Y. Incidentally, the end portion of the first electrode 61 facing the second electrode 62 and the end portion of the second electrode 62 facing the first electrode 61 may be in contact with each other entirely or partially.
Even in the third embodiment, the same effect as in the second embodiment can be obtained.
The first electrode 61 and the second electrode 62 are each electrically connected to the power line PL as illustrated in
The first electrode 61 is formed with a plurality of electrode elements 61A arranged along the contact portion AB, and the second electrode 62 is formed with a plurality of electrode elements 62B arranged along the contact portion AB. For example, the number of the plurality of electrode elements 61A may be the same as the number of pixel electrodes 14A arranged in the second direction Y, and a pitch of the electrode element 61A is equal to a pitch of the pixel electrode 14A. The plurality of electrode elements 62B are also configured in the same manner as the electrode elements 61A. The electrode elements 61A and the electrode elements 62B are arranged spaced apart in the first direction X with the contact portion AB interposed therebetween, and are insulated from each other.
In such configuration example, an electrophoretic layer 22 of a sub-area 4AB is driven by the plurality of electrode elements 61A and 62B arranged in the second direction Y. In addition, each of the electrode elements 61A and each of the electrode elements 62B can be supplied with individual electric potentials. For this reason, in the sub-area 4AB, not only the same display pattern entirely but also various patterns such as horizontal lines extending in the first direction X can be displayed.
Even if the electrode elements 62B are disposed to be shifted in the second direction Y with respect to the electrode elements 61A, the electrode elements 61A and 62B are insulated from each other and are supplied with individual electric potentials, so that there is no influence on the display in the sub-area 4AB.
The first electrode elements 611 and 621 are arranged spaced apart in the first direction X with the contact portion AB interposed therebetween. Incidentally, as described in the third embodiment, the first electrode elements 611 and 621 may be in contact with each other.
In the example illustrated in
In the example illustrated in
The connection structure described here can also be applied to the connection structure between the pixel electrode 14B and the electrode element 62B illustrated in
A drive circuit 12A of the drive substrate 1A is provided between the pixel electrode 14A located at the outermost periphery of the active area 3A and an end portion 102A on a side opposite to an end portion 101A in the first direction X. The drive circuit 12A includes a gate driver that scans all pixel rows in the active area 3A. Incidentally, the pixel row includes pixel electrodes or pixels arranged in the first direction X. In the drive substrate 1A, no drive circuit is provided in an area along the end portion 101A.
A drive circuit 11B of the drive substrate 1B is provided between the pixel electrode 14B located at the outermost periphery of the active area 3B and an end portion 101B on a side opposite to an end portion 102B in the first direction X. The drive circuit 12B includes a gate driver that scans all pixel rows in the active area 3B. In the drive substrate 1B, no drive circuit is provided in an area along the end portion 102B.
A pitch between the pixel electrode 14A and the pixel electrode 14B is substantially equal to a pitch of the pixel electrode 14A in the active area 3A or a pitch of the pixel electrode 14B in the active area 3B. For this reason, in the display area DA, an image can be displayed in the vicinity of the contact portion AB as well as the other areas, and the joint is hardly visually recognized.
Such drive substrate 1B has the same configuration as the drive substrate 1A except that the conductive layer 50 is provided. For this reason, a large display device DSP can be realized by arranging substantially the same drive substrates side by side. In addition, cost is reduced as compared with a case of preparing a plurality of drive substrates having different configurations.
As described above, according to the present embodiment, it is possible to provide a display device capable of achieving a large screen.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-154631 | Aug 2019 | JP | national |
This application is a Continuation Application of PCT Application No. PCT/JP2020/027502, filed Jul. 15, 2020 and based upon and claiming the benefit of priority from Japanese Patent Application No. 2019-154631, filed Aug. 27, 2019, the entire contents of all of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2020/027502 | Jul 2020 | US |
| Child | 17675100 | US |
