The present invention relates to a display device.
In recent display panels, in response to the demand for narrower frames, the corner portions of the originally rectangular display panel are rounded according to the outer shape of the housing, and the display area also has a similar shape accordingly (International Publication WO2007/105700). Furthermore, it is required to reduce the width of the frame surrounding the display area, including the rounded corner portions, as much as possible.
The scanning circuit arranged in the frame includes a shift register circuit that outputs a scanning signal to a plurality of scanning lines, and the shift register includes, for example, a multi-stage flip-flop. Since the scanning circuit is arranged along the ends of the display area, the scanning circuit can be arranged linearly in a normal rectangular display area, but at the corner portions, it is necessary to arrange the scanning circuit in a layout different from the straight side portions of the display area. Alternatively, if the scanning circuit is arranged at the corner portions in the same layout as the straight side portions, the layout efficiency is deteriorated. In particular, on the side that is electrically connected to the outside, it is necessary to arrange the routing wiring (oblique wiring), and the layout is more difficult.
Therefore, it is conceivable that the scanning circuit arranged in the corner portions is arranged in other vacant areas such as the upper or lower side of the display area. However, if the scanning circuit is arranged on the upper or lower side of the display area, since the distance from the output of the scanning circuit to the pixel circuit increases, the scanning lines become longer outside the display area. If the scanning line is long, the load increases, and the rising and falling of the applied pulse are delayed. As a result, a difference occurs in the delay or rounding of the pulse applied to the scanning line between the straight side portion and the corner portion, and there is a concern that a horizontal band may be seen in the displayed image.
An object of the present invention is to arrange a control circuit in a narrow area without increasing the load on a control line.
The display device according to the present invention includes a display area in which a plurality of pixel circuits respectively corresponding to a plurality of pixels are arranged in a first direction and a second direction intersecting each other; a peripheral area outside the display area; a plurality of control lines connected to the plurality of pixel circuits in the display area and extending in the first direction to reach the peripheral area; and a control circuit for sequentially selecting the plurality of control lines in the peripheral area, in which the control circuit includes a shift register including a plurality of unit circuits connected in multiple stages so that a pulse signal is sequentially moved and output, a plurality of enable circuits connected to the plurality of unit circuits so that the pulse signal is input, and a plurality of connection lines connecting the plurality of unit circuits and the plurality of enable circuits; the plurality of enable circuits are respectively adjacent to the display area in the first direction and connected to the plurality of control lines to output a control signal corresponding to the pulse signal; and the plurality of unit circuits include a first group of unit circuits adjacent to the display area in the first direction, and a second group of unit circuits located adjacent to the display area in the second direction; the plurality of connection lines include a first group of connection lines connected to the first group of unit circuits, and a second group of connection lines connected to the second group of unit circuits; and the connection lines of the second group are longer than the connection lines of the first group.
According to the present invention, since the plurality of unit circuits of the shift register are arranged adjacent to the display area not only in the first direction but also in the second direction, the control circuit can be arranged in a narrow area. Further, since all of the plurality of control lines are connected to the plurality of enable circuits adjacent to the display area in the first direction, there is no significant difference in the load of the control lines even though the distance from the unit circuit is different.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be carried out in various modes without departing from the gist of the present invention, and is not to be construed as being limited to the description of the embodiments exemplified below.
The drawings may be schematically illustrated in terms of width, thickness, shape, and the like of each portion as compared with actual embodiments in order to make the description clearer, but are merely examples, and are not intended to limit the interpretation of the present invention. In the specification and the drawings, elements having the same functions as those described in relation to the already described drawings are denoted by the same reference numerals, and the redundant description may be omitted.
Furthermore, in the detailed description of the present invention, when defining the positional relationship between a certain component and another component, the terms “above” and “below” include not only the case where located directly above or below the certain component, but also the case where other components are further interposed therebetween unless otherwise specified.
The display device includes a display area DA where an image is displayed. In the example of
There is a peripheral area PA outside the display area DA. The peripheral area PA has a uniform width adjacent to the first side S1, the second side S2, and the third side S3. In the peripheral area PA, a control circuit DR (or a scanning circuit or a gate driver circuit) is provided. The flexible printed circuit board 11 is connected to the peripheral area PA. An integrated circuit 12 is mounted on the flexible printed circuit board 11.
On the substrate 10, a three-layer laminated structure of a silicon oxide film 14a, a silicon nitride film 14b, and a silicon oxide film 14c is provided as an undercoat layer 14. The lowermost silicon oxide film 14a is provided for improving adhesion to the substrate 10, the intermediate silicon nitride film 14b is provided as a block film against moisture and impurities from the outside, and the uppermost silicon oxide film 14c is provided as a block film for preventing hydrogen atoms contained in the silicon nitride film 14b from diffusing to a semiconductor layer 18 side of a thin film transistor TR. However, the structure is not particularly limited to this structure, and may be further laminated, or may be a single layer or a two-layer laminate.
Under the undercoat layer 14, an additional film 16 may be formed at a position where the thin film transistor TR is formed. The additional film 16 can suppress a change in the characteristics of the thin film transistor TR due to the intrusion of light from the back surface of the channel, or can give a back gate effect to the thin film transistor TR by being formed of a conductive material and giving a predetermined potential. Here, after forming the silicon oxide film 14a, the additional film 16 is formed in an island shape in accordance with the position where the thin film transistor TR is to be formed, and then the silicon nitride film 14b and the silicon oxide film 14c are laminated, and thus, the additional film 16 is formed to be sealed in the undercoat layer 14. The present invention is not limited thereto. The additional film 16 may be first formed on the substrate 10, and then the undercoat layer 14 may be formed.
The thin film transistor TR is formed on the undercoat layer 14. Only an Nch transistor is illustrated here by taking a polysilicon thin film transistor as an example, but a Pch transistor may be formed at the same time. The semiconductor layer 18 of the thin film transistor TR has a structure in which a low-concentration impurity region is provided between a channel region and a source and drain region. Here, a silicon oxide film is used as a gate insulating film 20. A gate electrode 22 is a part of a first wiring layer W1 formed of MoW. The first wiring layer W1 includes a first storage capacitance line CL1 in addition to the gate electrode 22. A part of a storage capacitor Cs is formed between the first storage capacitance line CL1 and the semiconductor layer 18 (source and drain region) via the gate insulating film 20.
On the gate electrode 22, an interlayer insulating film 24 (silicon oxide film and silicon nitride film) is laminated. When allowing the substrate 10 to be bent, at least a part of the interlayer insulating film 24 is removed in a bending area FA to be easily bent. Since the undercoat layer 14 is exposed by removing the interlayer insulating film 24, at least a part thereof is also removed by patterning. After removing the undercoat layer 14, the polyimide constituting the substrate 10 is exposed. In some cases, the polyimide surface may be partially eroded through etching of the undercoat layer 14 to reduce the film thickness.
On the interlayer insulating film 24, a second wiring layer W2 including a portion serving as a source and drain electrode 26 and a routing wiring 28 is formed. Here, a three-layer laminated structure of Ti, Al and Ti is employed. The first storage capacitance line CL1 (part of the first wiring layer W1) and a second storage capacitance line CL2 (part of the second wiring layer W2) form a part of another storage capacitor Cs via the interlayer insulating film 24. The routing wiring 28 extends to an end of the substrate 10 to include a terminal 32 for connecting the flexible printed circuit board 11.
A planarizing film 34 is provided to cover the source and drain electrode 26 and the routing wiring 28 (except for a part thereof). As the planarizing film 34, an organic material such as photosensitive acrylic is often used because the organic material has better surface planarization than an inorganic insulating material formed by chemical vapor deposition (CVD) or the like.
The planarizing film 34 is removed at a pixel contact portion 36 and the peripheral area PA, and an indium tin oxide (ITO) film 35 is formed thereon. The indium tin oxide film 35 includes a first transparent conductive film 38 and a second transparent conductive film 40 separated from each other.
The second wiring layer W2 whose surface is exposed by removing the planarizing film 34 is covered with the first transparent conductive film 38. A silicon nitride film 42 is provided on the planarizing film 34 to cover the first transparent conductive film 38. The silicon nitride film 42 has an opening in the pixel contact portion 36, and a pixel electrode 44 is laminated so as to be conducted to the source and drain electrode 26 through the opening. The pixel electrode 44 is formed as a reflective electrode and has a three-layer laminated structure of an indium zinc oxide film, an Ag film, and an indium zinc oxide film. Here, the indium tin oxide film 35 may be used instead of the indium zinc oxide film. The pixel electrode 44 extends laterally from the pixel contact portion 36 and reaches above the thin film transistor TR.
The second transparent conductive film 40 is provided adjacent to the pixel contact portion 36, below the pixel electrodes 44 (further below the silicon nitride film 42). The second transparent conductive film 40, the silicon nitride film 42, and the pixel electrode 44 are overlapped to form an additional capacitor Cad.
On the surface of the terminal 32, a third transparent conductive film 46 which is another part of the indium tin oxide film 35 is formed. The third transparent conductive film 46 is formed simultaneously with the first transparent conductive film 38 and the second transparent conductive film 40. The third transparent conductive film 46 on the terminal 32 is provided as a barrier film so that an exposed portion of the terminal 32 is not damaged in a subsequent process. At the time of patterning the pixel electrode 44, the third transparent conductive film 46 is exposed to an etching environment. However, the indium tin oxide film 35 has sufficient resistance to the etching of the pixel electrode 44 by an annealing process performed between the formation of the indium tin oxide film 35 and the formation of the pixel electrode 44.
On the planarizing film 34, for example, above the pixel contact portion 36, an insulating layer 48 which is called a bank (rib) and serves as a partition between adjacent pixel regions is formed. As the insulating layer 48, photosensitive acrylic or the like is used similarly to the planarizing film 34. The insulating layer 48 is opened to expose the surface of the pixel electrode 44 as a light emitting region, and the opening end preferably has a gentle taper shape. If the opening end has a steep shape, poor coverage of an organic electro luminescence (EL) layer 50 formed thereon will occur.
The planarizing film 34 and the insulating layer 48 are in contact through an opening provided in the silicon nitride film 42 therebetween. Thus, moisture and gas desorbed and degassed from the planarizing film 34 can be extracted through the insulating layer 48 by heat treatment or the like after the formation of the insulating layer 48.
The organic EL layer 50 made of an organic material is laminated on the pixel electrode 44. The organic EL layer 50 may be a single layer, or may have a structure in which a hole transport layer, a light emitting layer, and an electron transport layer are sequentially laminated from the pixel electrode 44 side. These layers may be formed by vapor deposition, may be formed by coating over a solvent dispersion, or may be formed selectively with respect to the pixel electrode 44 (each sub-pixel). Alternatively, these layers may be formed by solid formation on the entire surface covering the display area DA. In the case of solid formation, white light can be obtained in all sub-pixels, and a desired color wavelength portion can be extracted by a color filter (not illustrated).
A counter electrode 52 is provided on the organic EL layer 50. Here, the counter electrode 52 is transparent due to the top emission structure. For example, the Mg layer and the Ag layer are formed as films thin to an extent that transmits light emitted from the organic EL layer 50. According to the above-described order of forming the organic EL layer 50, the pixel electrode 44 serves as an anode and the counter electrode 52 serves as a cathode. The counter electrode 52 is formed over the display area DA and over a cathode contact portion 54 provided near the display area DA. The counter electrode 52 is connected to the lower routing wiring 28 at the cathode contact portion 54 and electrically connected to the terminal 32.
A sealing film 56 is formed on the counter electrode 52. One function of the sealing film 56 is to prevent the previously formed organic EL layer 50 from the intrusion of moisture from the outside, and a high gas barrier property is required. Here, the laminated structure including the silicon nitride film is a laminated structure of a silicon nitride film 56a, an organic resin layer 56b, and a silicon nitride film 56c. A silicon oxide film or an amorphous silicon layer may be provided between the silicon nitride films 56a and 56c and the organic resin layer 56b for the purpose of improving adhesion.
If necessary, a cover glass, a touch panel substrate or the like may be provided on the sealing film 56. In this case, in order to fill the gap between the sealing film 56 and the cover glass or the touch panel, a filler using a resin or the like may be interposed.
As illustrated in
The plurality of unit circuits SR include a first group of unit circuits SR1 located adjacent to the display area DA in the first direction D1, and a second group of unit circuits SR2 located adjacent to the display area DA in the second direction D2. According to the present embodiment, the plurality of unit circuits SR of the shift register 60 are arranged adjacent to the display area DA not only in the first direction D1 but also in the second direction D2. The control circuit DR can be arranged in the narrow peripheral area PA. In particular, as illustrated in
As illustrated in
The control circuit DR includes an enable line 68 for inputting an enable signal E (
According to the present embodiment, all of the plurality of control lines GL are connected to the plurality of enable circuits EN adjacent to the display area DA in the first direction D1. Therefore, even though the distances from the unit circuit SR are different, there is no significant difference in the load on the control line GL.
According to the present embodiment, the delay of the pulse signal Q is reset at the timing of the enable signal E input to the enable circuit EN at the node between the output from the shift register 60 and the input to the enable circuit EN, even though the delay amount varies due to the uneven load. Therefore, even though the shift register 60 is separated from the control line GL (scanning line), it is possible to provide a configuration in which the variation in the delay and the amount of bluntness of the control signal G hardly occurs.
The plurality of enable circuits EN are divided into a plurality of groups GEN. One group GEN includes two or more enable circuits EN. One unit circuit SR is connected in parallel to each of two or more enable circuits EN forming one group GEN. Two or more enable lines 268a, 268b, and 268c are connected to the plurality of enable circuits EN. In the same group GEN, two or more enable circuits EN are connected to different enable lines 268a, 268b, and 268c. Each of the enable lines 268a, 268b, and 268c is connected to one enable circuit EN included in each of the different groups GEN.
The gate electrode of the driver transistor DRT is connected to the storage capacitor Cs. The drain electrode of the driver transistor DRT is connected to the reset switch transistor RST included in the control circuit DR via the control line GL2. The source electrode of the driver transistor DRT is connected to one electrode of the light emitting element LE. The other electrode of the light emitting element LE is connected to the power supply voltage Vss common to all the pixel circuits PX and is kept at a predetermined potential.
The reset switch transistor RST switches between conduction and non-conduction between the control line GL2 and a reset potential line RSL according to the pulse signal Q (
The pixel switch transistor SST switches between conduction and non-conduction between the video signal line DL and the gate electrode of the driver transistor DRT according to the control signal G (
The plurality of control lines GL are divided into a plurality of groups GGL1 and GGL2. The control line GL constituting one group GGL1 (GGL2) is connected to one of any control circuit DR1 (DR2). The plurality of control lines GL are divided into a plurality of sets SET. The control lines GL constituting one set SET include control lines GL of different groups GGL1 (GGL2) one by one. The pixel circuits PX arranged in one row are connected to one set SET of control lines GL. The other contents correspond to the contents described in the first embodiment.
The display device illustrated in
The display device is not limited to the organic electroluminescence display device, and may be a display device including a light emitting element such as a quantum-dot light emitting diode (QLED) in each pixel, or a liquid crystal display device.
While there have been described what are at present considered to be certain embodiments, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover all such modifications as fall within the true spirit and scope of the invention.
Number | Date | Country | Kind |
---|---|---|---|
2017-207994 | Oct 2017 | JP | national |
This application is a continuation application of International Application PCT/JP2018/028228 filed on Jul. 27, 2018, which claims priority from Japanese patent application JP2017-207994 filed on Oct. 27, 2017. The contents of these applications are incorporated herein by reference in their entirety.
Number | Date | Country | |
---|---|---|---|
Parent | PCT/JP2018/028228 | Jul 2018 | US |
Child | 16846855 | US |