Touch screen and display equipment

Abstract

A touch screen is provided that prevents a display from being affected by noise and reduces moiré. An embodiment of the touch screen comprises: an emission layer formed on a substrate; a barrier layer sealing the emission layer; an adhesive layer having a given thickness; and a passivation layer disposed on the barrier layer through the adhesive layer, the passivation layer having an emission electrode and a receiving electrode of a touch screen sensor; wherein the distance X between the end of the emission layer and the end of the emission electrode or the receiving electrode on a horizontal plane parallel to the display surface, the width L of the emission electrode and the receiving electrode, and the distance Y between the emission layer and the receiving electrode in a direction perpendicular to the display surface satisfy 5L≤Y≤X.

Description

Technical Field

[0001] The present invention relates to a touch screen including a touch screen sensor. Background Art

[0002] The touch screen integrates a touch screen sensor that detects the contact position of a finger or stylus on the display surface of the touch screen. There are known resistive film type touch screen sensors, electromagnetic induction type touch screen sensors, electrostatic capacitance type touch screen sensors, etc. The electrostatic capacitance type is further divided into self-capacitance type and projected electrostatic capacitance type, the latter type is capable of multi-point detection and is often used in portable terminals.

[0003] The projected electrostatic capacitive touch screen has a plurality of transmitting electrodes arranged parallel to the X-axis direction and a plurality of receiving electrodes arranged parallel to the Y-axis direction, and both the transmitting electrodes and the receiving electrodes are formed on the display surface of the touch screen. A pulse voltage signal is applied to the transmitting electrodes, and the transmitting electrodes are scanned in sequence to detect the change in capacitance between the electrodes caused by contact with a finger or a stylus by means of the voltage change of the receiving electrodes. The coordinates of the contact position of the finger, etc. are specified based on the scanning of the voltage signal and the arrangement of the electrodes.

[0004] The transmitting electrode and the receiving electrode have a large number of silver, copper or aluminum thin metal wires, which are arranged in parallel from one side to the other on the display surface of the touch screen. Therefore, as the size of the display increases, the resistance value of the electrode increases, so that the time constant increases, thereby reducing the detection speed. On the other hand, when the width of the thin metal wire increases, the transparency of the display decreases. Therefore, a large number of thin metal wires are arranged in a grid form to surround the light-emitting elements (pixels) of the display, thereby suppressing the increase in resistance value while maintaining transparency.

[0005] However, since the thin metal wires arranged in a grid form on the light-emitting elements of the display have periodicity related to the arrangement of the light-emitting elements, moiré patterns are generated. In view of this, the electrodes are arranged as directly as possible above the light-emitting elements to suppress the influence of interference as much as possible (for example, refer to Patent Document 1), or the thin metal wires are randomly arranged so as not to have periodicity (for example, refer to Patent Documents 2 and 3).

[0006] However, arranging the electrodes directly above the light-emitting elements shortens the distance between the electrodes of the display and the electrodes of the touch screen sensor, causing noise due to parasitic capacitance, thereby reducing the signal-to-noise (S / N) ratio. In addition, as disclosed in Patent Documents 2 and 3, even if the thin metal wires are randomly arranged, the periodic structure cannot be completely eliminated, making it difficult to completely remove the moiré pattern. In addition, since the light from the light-emitting element is diffusely reflected by the thin metal wires, the screen image displayed on the display becomes a textured screen image.

[0007] Citation List

[0008] Patent Literature

[0009] PTL 1: U.S. Patent No. 9,671,914

[0010] PTL 2: U.S. Patent No. 9,024,197

[0011] PTL 3: U.S. Patent Publication No. 2017 / 0309364 Summary of the invention

[0012] An object of the present invention is to provide a touch screen which can prevent a display from being affected by noise and reduce moiré patterns.

[0013] To achieve this purpose, an embodiment of the touch screen of the present invention includes: an emitting layer formed on a substrate; a barrier layer sealing the emitting layer; an adhesive layer having a given thickness; and a passivation layer arranged on the barrier layer through the adhesive layer, the passivation layer having an emitting electrode and a receiving electrode of a touch screen sensor; wherein a distance X between an end of the emitting layer and an end of the emitting electrode or the receiving electrode on a horizontal plane parallel to a display surface, a width L of the emitting electrode and the receiving electrode, and a distance Y between the emitting layer and the receiving electrode in a direction perpendicular to the display surface satisfy 5L≤Y≤X.

[0014] According to this configuration, by determining the thickness between the OLED and the receiving electrode according to the arrangement of the electrodes of the OLED and the touch screen sensor, moiré is output outside the viewing angle, thereby preventing moiré. In addition, since the distance between the OLED and the receiving electrode can be fixed, the noise generated by the parasitic capacitance can be suppressed.

[0015] The transmitting electrode and the receiving electrode may be composed of meshed thin metal wires. The thin metal wires are arranged in a mesh form to suppress an increase in the electrode resistance value.

[0016] Preferably, the meshed thin metal wire includes segments constituting a mesh, and the segments are randomly shifted to the left or right of the position of the original edge. Since the inclination of each edge constituting the mesh does not change when the edge is shifted, the formation of a texture image can be suppressed.

[0017] Preferably, the area occupied by the receiving electrode should be smaller than the area occupied by the transmitting electrode. The area of ​​the receiving electrode is set to be smaller than the area of ​​the transmitting electrode so that the receiving electrode is less affected by the noise caused by the parasitic capacitance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] [ Figure 1 ] Figure 1 is a cross-sectional view showing a first example of a touch screen;

[0019] [ Figure 2 ] Figure 2 is a perspective view showing a first example of electrodes of a touch screen sensor;

[0020] [ Figure 3 ] Figure 3 is a cross-sectional view showing a second example of a touch screen;

[0021] [ Figure 4 ] Figure 4 is a pattern diagram showing a second example of electrodes of a touch screen sensor;

[0022] [ Figure 5 ] Figure 5 is a cross-sectional view showing a touch screen provided by one embodiment of the present invention;

[0023] [ Figure 6 ] Figure 6 is a graph showing the relationship between the viewing angle and the brightness of an OLED display;

[0024] [ Fig. 7A ] Fig. 7A is a pattern diagram showing a third example of electrodes of a touch screen sensor;

[0025] [ Figure 7B ] Figure 7B is a diagram showing a pattern near a cross point in a third example of an electrode;

[0026] [ Fig. 8A ] Fig. 8A 1 is a diagram showing a pattern of electrodes of the touch screen of the present embodiment;

[0027] [ Figure 8B ] Figure 8B is a pattern diagram showing neighboring points of the intersection of electrodes of this embodiment;

[0028] [ Fig. 9A ] Fig. 9A is a pattern diagram showing a fourth example of electrodes of a touch screen sensor;

[0029] [ Fig. 9B ] Fig. 9B 1 is a diagram showing a pattern of electrodes of a touch screen sensor of the present embodiment;

[0030] [ Fig. 9C ] Fig. 9C is a schematic diagram showing electrodes of the touch screen sensor of this embodiment;

[0031] [ Fig.10 ] Fig.10 is a diagram showing a pattern of transmitting electrodes and receiving electrodes of a touch screen sensor;

[0032] [ Fig.11A ] Fig.11A is a diagram showing a first example of arrangement of electrodes and an emission layer of the touch screen sensor of the present embodiment;

[0033] [ Fig. 11B ] Fig. 11B is a diagram showing a second example of the arrangement of electrodes and an emission layer of the touch screen sensor of the present embodiment;

[0034] [ Fig.12 ] Fig.12 is a diagram showing a pattern of electrodes of a touch screen including an image sensor. DETAILED DESCRIPTION

[0035] The embodiments of the present invention will be described below in conjunction with the accompanying drawings. First, the schematic configuration of the touch screen and the generation of moiré patterns are described.

[0036] Figure 1 1 is a cross-sectional view showing a first example of a touch screen. In the touch screen 10, an emission layer 12 is formed on a substrate 11, in which organic light emitting diodes (OLED) R, G and B arranged in an array are buried, as well as a driving circuit including a thin film transistor (TFT) and an anode electrode. An electrode layer 13 serving as a cathode electrode is formed on the emission layer 12. In order to seal the above items, a thin film encapsulation (TFE) layer 14 is formed as a barrier layer. In addition, a transparent substrate 16 is provided through an adhesive layer 15, and an emitting electrode 21 of a touch screen sensor is formed on the transparent substrate 16. A passivation layer 17 covers the transparent substrate 16 and the emitting electrode 21, and a receiving electrode 22 of the touch screen sensor is formed on the passivation layer 17. Finally, an overcoating (OC) layer 18 is provided as a protective layer.

[0037] Display devices such as mobile terminals, monitors of personal computers, and televisions are composed of a plurality of OLEDs arranged in an array and a driving circuit for driving each OLED.

[0038] According to this configuration, the touch screen sensor is provided through the transparent substrate 16 so that a sufficient distance can be set between the electrode layer 13 of the OLED (R: red, G: green, B: blue) and the electrode of the touch screen sensor, thereby suppressing noise caused by parasitic capacitance.

[0039] Figure 22 is a perspective view showing electrodes of a touch screen sensor of the related art. The transmitting electrode 21 is a coil thin metal wire arranged parallel to the X-axis direction of the touch screen, and the receiving electrode 22 is a coil thin metal wire arranged parallel to the Y-axis direction. Figure 2 As shown, for example, the coordinates of the finger contact position are specified by applying a voltage pulse V to the emitter electrodes 21 in sequence starting from the upper emitter electrode 21 on the display surface. COT , and detect the voltage change of the receiving electrode 22.

[0040] When periodically arranged thin metal wires and periodically arranged OLEDs overlap, a structure with a new periodicity appears according to the relative relationship between the arrangements. The interference fringes generated by this relative relationship are moiré fringes, which have a period obtained by the periodic combination of the thin metal wires and the OLEDs. When there is a difference between the arrangement period of the thin metal wires and the arrangement period of the OLEDs, interference fringes corresponding to the difference are also generated. If Figure 2 The patterns of the transmitting electrode 21 and the receiving electrode 22 shown are arranged in the gaps between the OLEDs (R, G, B), and the periods of the thin metal wires and the OLEDs can be the same as each other. If the thin metal wires are separated from the OLEDs, the relative positional relationship will change with a slight change in the viewing angle, thereby generating moiré patterns.

[0041] Figure 3 3 is a cross-sectional view showing a second example of a touch screen. In the touch screen 30, an emission layer 32 is formed on a substrate 31, in which an OLED (R, G, and B) and a driving circuit including a TFT and an anode electrode are buried, and an electrode layer 33 serving as a cathode electrode is formed on the emission layer. A TFE layer 34 is formed to seal the above items, and a passivation layer 37 is formed on the TFE layer 34. An emitting electrode 41 and a receiving electrode 42 of the touch screen sensor are formed on the lower side and the upper side of the passivation layer 37, respectively. Finally, an OC layer 38 is provided as a protective layer.

[0042] like Figure 3 As shown, the transmitting electrode 41 and the receiving electrode 42 are arranged directly above the OLED (R, G, B), and the relative relationship between the arrangements changes only slightly even when the viewing angle changes, so as to suppress the generation of moiré. However, the distance between the electrode layer 13 of the OLED (R, G, B) and the electrode of the touch screen sensor is shortened, which will generate noise caused by parasitic capacitance.

[0043] Figure 4 is a pattern diagram showing a second example of electrodes of a touch screen sensor. As the size of a display increases, the resistance value of the electrode increases, and thus thin metal wires are arranged in a grid form to suppress the increase in resistance value.

[0044] In addition, as disclosed in Patent Document 2 or 3, Figure 4 The randomly arranged thin metal wires shown result in a random relative relationship between the arrangement of the thin metal wires and the arrangement of the OLEDs, so that the difference between the periods of the thin metal wires and the OLEDs does not become constant, thereby reducing moiré. However, as described above, even if the thin metal wires are randomly arranged, the periodic structure cannot be completely eliminated, and thus the moiré cannot be completely removed.

[0045] In this embodiment, in order to avoid the influence of noise caused by parasitic capacitance and further reduce moiré, a limited arrangement of OLEDs (R, G, B) and thin metal wires is configured.

[0046] Figure 5 is a cross-sectional view showing a touch screen provided by one embodiment of the present invention. In the touch screen 50, an emission layer 52 is formed on a substrate 51, an OLED (R, G, B) and a driving circuit including a TFT and an anode electrode are buried in the emission layer 52, and an electrode layer 53 used as a cathode electrode is formed on the emission layer. In order to seal the above items, a TFE layer 54 is formed as a barrier layer. In addition, a passivation layer 57 is provided on the TFE layer 54 through an adhesive layer 55 having a given thickness. The transmitting electrode 61 and the receiving electrode 62 of the touch screen sensor are formed on the lower side and the upper side of the passivation layer 57, respectively. Finally, an OC layer 58 is provided as a protective layer.

[0047] Here, the spacing between the OLEDs (R, G, B) is represented by S, the width of the transmitting electrode 61 or the receiving electrode 62 is represented by L, the distance between the end of the OLED (R, G, B) and the end of the transmitting electrode 61 or the receiving electrode 62 in the horizontal direction parallel to the display surface is represented by X, and the distance (thickness) between the OLED (R, G, B) and the receiving electrode 62 in the direction perpendicular to the display surface is represented by Y.

[0048] Figure 6 is a graph showing the relationship between the viewing angle and the brightness of an OLED display. Figure 6 The relationship between the viewing angle and the brightness of a general OLED display is shown, where the brightness seen from the normal line is set to "1". Considering that about 60% brightness can ensure the range of practical use of the display, the viewing angle is about 45 degrees.

[0049] Therefore, in this embodiment, if Figure 5 As shown, when the transmitting electrode 61 and the receiving electrode 62 are arranged in the gap between each OLED (R, G, B), the thickness Y between the receiving electrode 62 and the OLED is determined according to the interval X between the transmitting electrode 61 and the OLED in the horizontal plane. Considering the output angle defined by the refraction on the OC layer 58, the direction angle from the receiving electrode 62 to each OLED is 21 degrees from the normal line, and the following relationship should be satisfied in this embodiment.

[0050] [Equation 1]

[0051]

[0052] Y≤2.6X (Equation 1-2)

[0053] The bonding layer 55 having a given thickness according to the determined thickness Y is formed. According to the above arrangement, light emitted from the OLED R is output between the emitting electrode 61 and the receiving electrode 62, and is output through the OC layer 58 within a 45-degree viewing angle. Moire is an interference band generated due to the periodicity associated with the arrangement of the electrodes and the OLED. Therefore, moire is output outside the viewing angle.

[0054] Satisfying equation 1 in this way can fix the distance between the electrode of the OLED and the receiving electrode of the touch screen sensor in addition to preventing moiré, thereby suppressing the influence of noise caused by parasitic capacitance. The thickness Y is equal to or less than the interval X, which can be varied according to the specifications required for the display and can be actually applied.

[0055] Meanwhile, in view of suppressing noise caused by parasitic capacitance, the lower limit of the thickness Y preferably satisfies the following relationship.

[0056] Y ≥ 5.0L (Equation 2)

[0057] The width L of the transmitting electrode 61 or the receiving electrode 62 is preferably 2 μm or less, and is more preferably 1 μm or less in view of reducing parasitic capacitance.

[0058] In one implementation, if the interval S between OLEDs (R, G, B) is 20 μm, the width L of the electrode is 2 μm, and the distance X between the end of the OLED and the end of the electrode is 10 μm, the required thickness Y is 19 μm, and the direction angle from the receiving electrode 62 to each OLED is 28 degrees from the normal, thereby outputting moiré patterns outside the 45-degree viewing angle.

[0059] Fig. 7A is a pattern diagram showing a third example of electrodes of a touch screen sensor. Figure 4 The electrodes of the touch screen sensor shown in FIG. 1 slightly change the grid structure of the diamond rectangle. Specifically, as shown in FIG. Figure 7B As shown, the intersections of the original rhombus are arranged to be shifted to one intersection above, below, left, and right in the figure within a range of 10 μm or less. The shifted intersections are connected in such a way that the sides forming the rhombus become non-parallel to each other, so the thin metal wires do not have periodicity.

[0060] However, since the parallel line portion is not completely eliminated for the overall pattern of the electrode, the periodic structure cannot be completely eliminated, so that the moiré pattern cannot be completely removed. In addition, the inclination of one edge after the change may have a different angle relative to the inclination of one edge before the change, so that the display screen image becomes a more textured image.

[0061] Fig. 8A FIG. 1 is a diagram showing a pattern of electrodes of the touch screen of the present embodiment. Figure 8B As shown, the intersection of the rhombus is not shifted, but each side is shifted in parallel within a range of 10μm or less. Specifically, two consecutive sides on a straight line are randomly shifted together to the left or right of the original side position. Although the periodic structure cannot be completely eliminated, and the moiré pattern cannot be completely removed, as described above, the inclination of each side does not change relative to the inclination of each side before the change, so the conversion to a texture image can be suppressed.

[0062] The receiving electrode that detects a small potential difference is mainly affected by the noise caused by the parasitic capacitance between the electrode layer of the OLED and the electrode of the touch screen sensor. Therefore, in this embodiment, the area of ​​the receiving electrode is made smaller than that of the transmitting electrode, so that the receiving electrode is less affected by the noise.

[0063] Fig. 9A is a pattern diagram showing a fourth example of electrodes of a touch screen sensor. This diagram shows that when the electrodes are changed to Figure 4 , Fig. 7A or Fig. 8A When the mesh transmitting electrode and receiving electrode are shown, Figure 2 The coil transmission electrode and a portion of the reception electrode are shown. The solid line represents the reception electrode 72 formed on the display surface side of the passivation layer, and the dotted line represents the transmission electrode 71 formed on the transmission layer side.

[0064] Fig. 9B As described above, by setting the area occupied by the mesh receiving electrode 72 to be smaller than the area occupied by the transmitting electrode 71, the receiving electrode is less affected by the noise caused by the parasitic capacitance.

[0065] Fig. 9C is a schematic diagram showing electrodes of the touch screen sensor of the present embodiment. In addition, the area occupied by the mesh receiving electrode 72 can be made smaller to provide a grid in which electrodes are individually arranged like islands, so that the electrodes are arranged in a lattice form to the extent of specifying the coordinates of the finger contact position.

[0066] Fig.10 FIG. 1 is a diagram showing a pattern of a transmitting electrode and a receiving electrode of a touch screen sensor. Figure 2 and 9A to 9C As shown in FIG. 1 , the mesh transmitting electrode is formed on the passivation layer in directions perpendicular to each other. Therefore, preferably, the portion of each side of the mesh transmitting electrode parallel to each side of the mesh receiving electrode is reduced. Therefore, in this embodiment, as shown in FIG. Fig.10 As shown, the grid structure does not have Figure 4 , Fig. 9A and Fig. 9B The grid structure is a diamond-shaped rectangle as shown, but has dog-leg lines. In addition, each side of the transmitting electrode 81 and each side of the receiving electrode 82 intersect each other at the midpoint of each side, thereby reducing moiré.

[0067] Fig.11A and Fig. 11B The arrangement of the electrodes and the emission layer of the touch screen sensor of this embodiment is shown. According to the relationship of emission brightness, the OLEDs of each color of R, G and B have different occupied areas and different shapes. Fig.11A The configuration in which the pattern of the transmitting electrode and the receiving electrode is arranged in the gap between each OLED (R1-R2, G1-G4, B1-B2) is shown. Figure 5 The interval S between the OLEDs, the width L of the electrode, and the distance X between the end of the OLED and the end of the electrode are shown so that the thickness Y between the OLED and the receiving electrode should be determined based on the distance X according to Equation 1-2.

[0068] Fig. 11B The following case is shown: regardless of the arrangement of OLEDs (R1-R2, G1-G4, B1-B2), the patterns of the transmitting electrode and the receiving electrode are arranged so that the OLEDs and the electrodes overlap each other. In this case, the thickness Y between the OLED and the receiving electrode can be determined based on the interval S and the width L according to Equation 1-1.

[0069] Fig.12 is a diagram showing a pattern of electrodes of a touch screen including an image sensor. A touch screen integrating an image sensor such as a fingerprint sensor is known. This display integrates a photodiode with each pixel circuit including an OLED. Preferably, Fig.10 The configuration of the transmitting electrode 81 and the receiving electrode 82 of the touch screen sensor shown is applied to such a display. Fig.12 As shown, the transmitting electrode 81 and the receiving electrode 82 are arranged between each OLED of each color of R, G and B. The line connecting the R sub-pixel and the G sub-pixel, the line connecting the G sub-pixel and the B sub-pixel, and the line connecting the R sub-pixel and the B sub-pixel are not parallel to each other. Each edge of the transmitting electrode 81 and each edge of the receiving electrode 82 intersect each other. In addition, the interval of the electrodes of the image sensor is an integral multiple of the sub-pixel interval. According to the touch screen, the signal-to-noise ratio (S / N ratio) of the image sensor can be increased.

[0070] According to this embodiment, the thickness between the OLED and the receiving electrode is determined according to the arrangement of the electrodes of the OLED and the touch screen sensor, and the moiré pattern can be output outside the viewing angle, thereby preventing the moiré pattern. In addition, since the distance between the OLED and the receiving electrode can be fixed, the noise caused by the parasitic capacitance can be suppressed.

Claims

1. A touch screen, characterized in that: include: an emission layer formed on a substrate; a barrier layer sealing the emissive layer; a bonding layer having a given thickness disposed on the barrier layer; A passivation layer is provided on the barrier layer through the bonding layer, wherein the passivation layer has a transmitting electrode and a receiving electrode of a touch screen sensor; Among them, the distance X between the end of the emitting layer and the end of the emitting electrode or the receiving electrode on a horizontal plane parallel to the display surface, the width L of the emitting electrode and the receiving electrode, and the distance Y between the emitting layer and the receiving electrode in a direction perpendicular to the display surface satisfy 5L≤Y≤2.6X.

2. The touch screen according to claim 1, characterized in that: The distance X, the width L, and the distance Y satisfy 5L≤Y≤X.

3. The touch screen according to claim 1 or 2, characterized in that: The transmitting electrode and the receiving electrode are composed of meshed thin metal wires.

4. The touch screen according to claim 3, characterized in that: The meshed fine metal wires include segments forming a mesh, The segments are randomly shifted to the left or right of the location of the original edge.

5. The touch screen according to claim 3, characterized in that: The area occupied by the receiving electrode is smaller than the area occupied by the transmitting electrode.

6. The touch screen according to any one of claims 1, 2, 4 and 5, characterized in that: The distance Y is 2 μm or less.

7. The touch screen according to claim 3, characterized in that: The distance Y is 2 μm or less.

8. The touch screen according to any one of claims 1, 2, 4 and 5, characterized in that: The emission layer includes OLEDs arranged in an array on the substrate.

9. The touch screen according to claim 3, characterized in that: The emission layer includes OLEDs arranged in an array on the substrate.

10. The touch screen according to claim 8, characterized in that: The emission layer integrates photodiodes with the OLEDs disposed on the substrate in an array manner.

11. The touch screen according to claim 9, characterized in that: The emission layer integrates photodiodes with the OLEDs disposed on the substrate in an array manner.

12. A display device, characterized in that: include: The touch screen according to any one of claims 1 to 11, wherein an OLED is arranged on a substrate of the touch screen; A driving circuit for driving each of the OLEDs.

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