This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2017-25305, filed on Feb. 14, 2017; the entire contents of which are incorporated herein by reference.
Embodiments of the present invention described herein relate to a display device.
In these days, liquid crystal display devices provided with touch sensors are mounted on display devices such as smartphones. The liquid crystal display devices are provided with detection electrodes on surfaces of display panels. In response to a finger of a user touching this detection electrode, the liquid crystal display device detects the touched position and performs a predetermined operation.
In the liquid crystal display devices provided with the touch sensors, high-frequency pulses for touch sensing give rise to noise and adversely affect wireless communication performed by smartphones or the like, which is a problem.
In light of this problem, an object of embodiments of the present invention is to provide a display device that can minimize noise due to the high-frequency pulses for touch sensing.
According to embodiments, a display device includes a first insulating substrate; gate lines in a display region on the first insulating substrate, the gate lines being made from first metal wires; signal lines in the display region, the signal lines being orthogonal to the gate lines, the signal lines being made from second metal wires; pixels at positions where the gate lines and the signal lines intersect, each pixel including a switching element and a pixel electrode connected to the switching element; common electrodes in the display region, the common electrodes being made from first transparent electrodes extending in one direction, the common electrodes serving both as common electrodes and first sensor electrodes; third metal wires on the common electrodes; a common power supply line in one peripheral region of the first insulating substrate, the common power supply line configured to supply DC common voltage to the common electrodes; a sensor power supply line in the one peripheral region, the sensor power supply line configured to supply pulse sensor voltage to the common electrodes; selector switches in the one peripheral region, the selector switches configured to connect either the common power supply line or the sensor power supply line to the common electrodes; and a mesh-shaped shield portion on the sensor power supply line, the shield portion being formed using the same material as the third metal wires. In each embodiment, a display device provided with a display panel in which liquid crystal display elements are employed is disclosed as an example of the display device. It should be noted that each embodiment does not prevent application of respective technical ideas disclosed in each embodiment to display devices in which elements other than the liquid crystal display elements are employed. Examples of the display devices other than the liquid crystal display device include a self-emitting type display panel having organic electroluminescence display elements or the like and an electronic paper type display panel having electrophoresis elements or the like. A liquid crystal display device according to an embodiment of the present invention will be described hereinafter with reference to the accompanying drawings. While certain embodiments shall be described, the embodiments are presented by way of example only and are not intended to limit the scope of the invention. Indeed, the embodiments described herein may be embodied in a variety of other forms, and various omissions, substitution, and changes in the form of the embodiments may be made without departing from the spirit of the invention. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention. In the drawings, components may be shown schematically regarding the width, thickness, shape and the like, instead of being shown in accordance with the actual sizes, for the sake of clear illustration. The drawings are merely exemplary and do not limit the interpretations of the present invention in any way. In the specification and the drawings, components that are substantially the same as those depicted in a previous drawing(s) bear the identical reference signs thereto, and detailed descriptions thereof may be omitted. Applications of the liquid crystal display device according to the embodiments include lateral electric field display devices sometimes referred to as an in-plane switching (IPS) mode display devices, and particularly fringe field switching (FFS) mode display devices, which use fringe fields and are derived from IPS.
A liquid crystal display device according to a first embodiment will be described hereinafter with reference to
(1) Overall Configuration of Display Panel 1
A display panel 1 of the liquid crystal display device includes an array substrate 2, a counter substrate 3, a liquid crystal layer 4 held in a gap between the array substrate 2 and the counter substrate 3, and a sealing member 5 whereby peripheral regions 9 of the substrates 2 and 3 are adhered to each other to seal the liquid crystal layer 4. The display panel 1 includes a display region 8 for displaying images and the peripheral region 9 surrounding the display region 8.
(2) Circuitry Configuration of Display Panel 1
The circuitry configuration of the display panel 1 will be described hereinafter with reference to
As illustrated in
A signal line driver 52 and a signal selection circuit 53 are disposed in a lower peripheral region 9 of the array substrate 2. The signal line driver 52 outputs RGB image signals to the signal lines 15.
A gate driver 50 is disposed along the vertical direction in the left peripheral region 9 of the glass substrate 10. The gate driver 50 outputs gate signals to the gate lines 16.
(3) Structure of Touch Sensor
The structure of a touch sensor will be described hereinafter with reference to
Common electrodes 13 extend in the transverse direction (the x-axis direction) and are disposed at predetermined intervals in the vertical direction (the y-axis direction) on the array substrate 2. The common electrodes 13 serve both as common electrodes and first sensor electrodes.
Furthermore, a common power supply line 54 is wired along the vertical direction on the left side of the common electrodes 13 that extend to the peripheral region 9 of the array substrate 2. The common power supply line 54 supplies DC common voltage to the common electrodes 13 when the display panel 1 displays an image. A sensor power supply line 56 is wired along the vertical direction on the left side of the common power supply line 54. The sensor power supply line 56 supplies high-frequency pulses when the display panel 1 is used as a touch sensor.
The gate driver 50 described above is disposed on the left side of the sensor power supply line 56.
Selector switches 58 are disposed between the common power supply line 54 and the sensor power supply line 56. This selector switch 58 is provided for each of the common electrodes 13 that extend in the transverse direction. These selector switches 58 are used to select whether to supply the common electrodes 13 with the DC common voltage from the common power supply line 54 or the high-frequency pulses from the sensor power supply line 56.
An ENE circuit 60 is disposed between the common power supply line 54 and the display region 8. The ENE circuit 60 controls the ON/OFF timing of the gate signals output from the gate driver 50 to each of the gate lines 16.
The sensor power supply line 56 is connected to a first sensor controller 62. The first sensor controller 62 is disposed in the lower peripheral region 9 of the array substrate 2. The first sensor controller 62 outputs high-frequency pulse sensor voltage for the touch sensor to the sensor power supply line 56.
The common power supply line 54 and the selector switches 58 are also connected to the signal line driver 52. The signal line driver 52 supplies predetermined DC common voltage to the common power supply line 54, and outputs timing signals to the selector switches 58 for switching between displaying and touch sensing.
Second sensor electrodes (hereinafter simply referred to as “sensor electrodes”) 112 extend in the vertical direction (the y-axis direction) and are disposed at predetermined intervals in the transverse direction (the x-axis direction) on the surface of the counter substrate 3. Lower ends of the sensor electrodes 112 are connected to a second sensor controller 64. The second sensor controller 64 is disposed in the lower peripheral region 9 of the array substrate 2.
When the display panel 1 is used as a mutual capacitance type touch sensor, the selector switches 58 are switched to the position of the sensor power supply line 56 and the high-frequency pulses are supplied to the common electrodes 13. When the finger of a user contacts or is brought near to the sensor electrode 112, the capacitance between the sensor electrode 112 and the common electrode 13 changes, and the second sensor controller 64 detects the change and the position where the change in capacitance occurred.
The sensor electrodes 112 are not essential to some types of touch sensors. A structure in which electrodes are disposed only on the array substrate 2 also enables touch sensing. This structure may be employed. The present invention is even applicable to this case.
(4) Pixel 6
The structure of the pixel 6 will be described hereinafter with reference to
(5) Array Substrate 2
The structure of the array substrate 2 will be described hereinafter with reference to
A polysilicon interconnect 17 constituting the semiconductor of the TFT 7 is formed on the glass substrate 10 of the array substrate 2 (see
A gate insulating film 16C is formed on the polysilicon interconnect 17 (see
The gate lines 16 are formed in parallel in the transverse direction (the x-axis direction) at predetermined intervals on the gate insulating film 16C (see
A first insulating film 15B is formed on the gate line 16, the gate electrode branch line 16A, and the first metal wire 16B (see
The signal line 15 is formed in the vertical direction (the y-axis direction) on the first insulating film 15B (see
An organic insulating film (flattening film) 12 is formed on the first metal wire 16B and the signal line 15. The organic insulating film 12 is formed thicker on the signal line 15 and the vicinity thereof than at other portions, thereby forming the array protrusion 11 (see
The common electrode 13, which is made from transparent electrical conductive material such as ITO or IZO, is formed in the transverse direction (the x-axis direction) at a predetermined interval on the organic insulating film 12 of the array protrusion 11 (see
Additionally, a third metal wire 20 is formed in the transverse direction on the gate line 16 and the common electrode 13 (see
A second insulating film 13B is formed on the common electrode 13, the third metal wire 20, and the like (see
The pixel electrode 14 is disposed on the second insulating film 13B (see
An alignment film 18 is formed on the second insulating film 13B and the pixel electrode 14 (see
Next, a more detailed description of the array protrusion 11 is given. The height of the organic insulating film 12 of the array protrusion 11 is greater than the height of the organic insulating film 12 within the pixel opening portion 31, and the organic insulating film 12 of the array protrusion 11 extends along the direction of the signal line 15. As illustrated in
Additionally, as illustrated in
(6) Counter Substrate 3
The counter substrate 3 will be described hereinafter with reference to
A black matrix 102 is formed beneath a glass substrate 100 of the counter substrate 3. The black matrix 102 is provided in a grid pattern using a black resin material. The black matrix 102 includes a vertical portion extending along the signal line 15 so as to cover the signal line 15 and the vicinity of the signal line 15, and a transverse portion extending continuously along each TFT 7 and gate line 16. Thus, the black matrix 102 is formed in the grid pattern. Each opening portion in the grid pattern of the black matrix 102 corresponds to the pixel opening portion 31.
As illustrated in
An overcoat layer 106 made from resin is formed under the color filter layer 104.
A counter protrusion 108 is formed under the overcoat layer 106. The counter protrusion 108 has a rectangular shape with rounded corners and is formed along the gate line 16 from the signal line 15 to the TFT 7.
An alignment film 110 is formed under the overcoat layer 106 and under the counter protrusion 108. The alignment film 110 is in contact with the liquid crystal layer 4.
The sensor electrode (second sensor electrode) 112 extends along the vertical direction and is formed at a predetermined interval in the transverse direction (see
(7) Spacer
As illustrated in
The spacer formed in this manner can be provided at a ratio of one to a plurality of the pixels 6. For example, the spacer can be provided at a ratio of one per four of the pixels 6 or at a ratio of one per eight of the pixels 6.
As illustrated in
(8) Peripheral Region 9 of Display Panel 1
Next, the left peripheral region 9 in which the gate driver 50 of the display panel 1 is provided will be described.
As illustrated in
As illustrated in
The gate lead line 16D is formed in the transverse direction on the gate insulating film 16C. The gate lead line 16D extends from the display region 8 to the gate driver 50.
The first insulating film 15B is formed on the gate lead line 16D.
The sensor power supply line 56 is formed on the first insulating film 15B. The sensor power supply line 56 is made from the same material as the signal line 15. The slits 66 in the vertical direction are formed in the sensor power supply line 56.
The organic insulating film 12 is formed on the sensor power supply line 56.
A first shield layer 70 is formed on the organic insulating film 12 in a mesh shape. The first shield layer 70 is made from the same material as the common electrode 13.
A second shield layer 72 is formed on the first shield layer 70 in the same mesh shape. The second shield layer 72 is made from the same material as the third metal wire 20.
The second insulating film 13B is formed on the second shield layer 72.
A third shield layer 74 is formed on the second insulating film 13B in the same mesh shape. The third shield layer 74 is made from the same material as the pixel electrode 14.
The alignment film 18 is formed on the third shield layer 74.
The counter substrate 3 is adhered onto the array substrate 2 via the sealing member 5.
DC voltage is supplied to the first shield layer 70 and the second shield layer 72. As illustrated in
Note that the “mesh shape” means that the first shield layer 70, the second shield layer 72, and the third shield layer 74 are arranged in a regular manner vertically and transversely to form sides of rhombuses and the inner circumference of the rhombuses are opened as illustrated in
As illustrated in
As described above, the line width of the mesh-shaped first shield layer 70 and the line width of the mesh-shaped third shield layer 74 are 7 μm, and the line width of the mesh-shaped second shield layer 72 is 3 μm. As illustrated in
(9) Manufacturing Method of Array Substrate 2
An overview of the manufacturing method of the array substrate 2 will be described hereinafter with reference to
In a first process, as illustrated in
In a second process, as illustrated in
In a third process, as illustrated in
In a fourth process, as illustrated in
In a fifth process, the transparent organic insulating film 12 provided with the array protrusion 11 is formed. The signal line 15 and the first island pattern 15A are covered by the organic insulating film 12. Next, a contact hole 19B that exposes a portion of the first island pattern 15A is formed.
In a sixth process, as illustrated in
In an eighth process, as illustrated in
In a ninth process, as illustrated in
In a tenth process, the alignment film 18 made from resin is formed on the entirety of the array substrate 2. Finally, the array substrate 2 is subjected to photo alignment treatment by UV irradiation.
(10) Effects
According to this embodiment, the sensor power supply line 56 is covered by the mesh-shaped shield portion 68 including the first shield layer 70, the second shield layer 72, and the third shield layer 74. Therefore, even if the high-frequency pulse sensor voltage is supplied to the sensor power supply line 56, the parasitic capacitance can be reduced, which can provide the electro magnetic interference (EMI) countermeasure while minimizing the deterioration of the touch performance.
The second shield layer 72 made from the same material as the third metal wire 20 is stacked on the first shield layer 70 made from the transparent electrical conductive material, which achieves a lower resistance and further improves the shield effect.
The third shield layer 74 is formed on the first shield layer 70 and the second shield layer 72 in the mesh shape, which enhances the EMI countermeasure.
The first shield layer 70 is formed using the same material as the common electrode 13, the second shield layer 72 is formed using the same material as the third metal wire 20, and the third shield layer 74 is formed using the same material as the pixel electrode 14. Therefore, the respective shield layers 70, 72, 74 can be formed in the same manufacturing process as the display region 8.
The slits 66 are provided in the vertical direction at the predetermined intervals in the sensor power supply line 56. These are, for example, slits which allow light to pass therethrough toward the sealing member 5, which overlaps the light-shielding sensor power supply line 56 as illustrated in
(11) First Modification
In the above described embodiment, the coverage ratio of the mesh shape of the first shield layer 70, the second shield layer 72, and the third shield layer 74 is 49%, and the repeating pitch thereof is 35 μm×35 μm. The present disclosure is not limited to this embodiment. For example, the coverage ratio may be 26.5% and the repeating pitch may be 70 μm×70 μm as illustrated in
The coverage ratio is defined based on the assumption that the coverage ratio is 100% when no slit is formed in the sensor power supply line 56. The above described values, that is, 49%, 26.5%, and 13.8% are not necessarily accurate values. The coverage ratio may be defined by a range such as 48% to 51%, 24% to 27%, or 12% to 15%.
In this case, even if the high frequency pulse flows through the sensor power supply line 56, the shield effect of the shield portion 68 serves as the EMI countermeasure.
(12) Second Modification
In the above described embodiment, the power supply portions to which the voltage is supplied from the common power supply line 54 are provided at the upper and lower portions of the sensor power supply line 56 in the vertical direction. The present disclosure is not limited to this structure. As illustrated in
The voltage may be supplied from the common power supply line 54 to the third shield layer 74 for each selector switch 58.
(13) Third Modification
In the above described embodiment, the third shield layer 74 is formed on the second insulating film 13B in the same mesh shape. However, even if this third shield layer 74 is not provided, noise can be reduced.
A liquid crystal display device according to a second embodiment will be described hereinafter with reference to
When displaying images, the liquid crystal display device performs column inversion driving, line inversion driving, dot inversion driving, or frame inversion driving which inverts the polarity of image signals.
In order to invert the polarity of the image signals output to the signal lines 15, the signal selection circuit 53 is connected to the signal line driver 52. As illustrated in
In this embodiment, the mesh-shaped shield portion 68 covers an upper layer of the signal selection circuit 53 including the plurality of analog switches 200. The mesh-shaped shield portion 68 is, for example, made from the same material as the third metal wire 20. The voltage is supplied from the common power supply line 54 to the mesh-shaped shield portion 68.
According to this embodiment, noise generated from the analog switches 200 constituting the signal selection circuit 53 can be reduced.
A liquid crystal display device according to a third embodiment will be described hereinafter with reference to
In the second embodiment, the mesh-shaped shield portion 68 only covers the signal selection circuit 53. In this embodiment, in addition to this structure, the mesh-shaped shield portion 68 covers upper layers of the first open-close signal wiring 204 and the second open-close signal wiring 206 which are connected to the signal selection circuit 53. The voltage is supplied from the common power supply line 54 to the mesh-shaped shield portion 68.
According to this embodiment, noise generated from the signal selection circuit 53, the first open-close signal wiring 204, and the second open-close signal wiring 206 can be reduced.
A liquid crystal display device according to a fourth embodiment will be described hereinafter with reference to
In the third embodiment, the mesh-shaped shield portion 68 covers the upper layer of the signal selection circuit 53. Instead of this structure, in this embodiment, a shield plane 208 made of a conductive layer entirely covers upper layers of the lead lines 202 of the signal lines 15. The shield plane 208 is, for example, formed from a second transparent electrode which is the same material as the pixel electrode 14. The voltage is supplied to the shield plane 208 from the common power supply line 54 located on left side of the display region 8.
According to this embodiment, noise generated from the lead lines 202 can be reduced.
A liquid crystal display device according to a fifth embodiment will be described hereinafter with reference to
In the first embodiment, the common electrodes 13 provided on the array substrate 2 are formed along the transverse direction (the x-axis direction) and the sensor electrodes 112 provided on the counter substrate 3 are formed along the vertical direction (the y-axis direction).
Instead of this structure, in this embodiment, the common electrodes 13 provided on the array substrate 2 are formed along the vertical direction (the y-axis direction) parallel to the signal lines 15, and the sensor electrodes 112 provided on the counter substrate 3 are formed along the x-axis direction parallel to the gate lines 16.
In this case, the common power supply line 54 and the sensor power supply line 56 are formed in the transverse direction. The common power supply line 54 and the sensor power supply line 56 are formed in the lower peripheral region 9 of the array substrate 2. Thus, the shield portion 68 is formed on the upper layer of the sensor power supply line 56 in the mesh shape. The shield portion 68 includes the first shield layer 70, the second shield layer 72, and the third shield layer 74.
Provided that they encompass the spirit of the invention, all embodiments implementable by a person skilled in the art making design changes or modifications to the embodiments described above should be construed to be within the scope of the present invention.
Various modifications and alterations can be conceived by those skilled in the art within the spirit of the present invention, and it is understood that such modifications and alterations are also encompassed within the scope of the present invention. For example, those skilled in the art can suitably modify the above-described embodiment by addition, deletion, or design change of components, or by addition, omission, or condition change of steps. Such modifications are also encompassed within the scope of the present invention as long as they include the gist of the present invention.
Other advantageous effects that are provided by the embodiments and that are obvious from the present specification or appropriately conceivable by those skilled in the art are naturally provided by the present invention.
Number | Date | Country | Kind |
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JP2017-025305 | Feb 2017 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
20150062054 | Yun | Mar 2015 | A1 |
20150248044 | Kimura | Sep 2015 | A1 |
20150268795 | Kurasawa | Sep 2015 | A1 |
20160291786 | Yokoi | Oct 2016 | A1 |
20180181234 | Hammura | Jun 2018 | A1 |
Number | Date | Country |
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H1195202 | Apr 1999 | JP |
Entry |
---|
Aoki et al., Machine Translation of Foreign Patent Document JPH 1195202A, Active Matrix Type Liquid Crystal Display Device, Apr. 9, 1999, pp. 1-7 (Year: 1999). |
Number | Date | Country | |
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20180231853 A1 | Aug 2018 | US |