KR100563040B1 - Touch Panel with uniform activation force in touch sensitive surfce - Google Patents

Abstract

The present invention relates to a touch panel attached to an image display device such as a liquid crystal display device, etc. The present invention relates to an upper substrate having an upper transparent conductive film formed between upper electrode lines, and a lower substrate having a lower transparent conductive film formed between lower electrode lines; And a plurality of dot spacers formed between the upper transparent conductive layer and the lower transparent conductive layer to prevent contact between upper and lower transparent conductive layers when a predetermined pressing force is not applied. Disclosed is a touch panel in which a distribution of dot spacers in a central portion is different so that the minimum pressing force acting on the upper substrate becomes 90% or more of the maximum pressing force.

Description

Touch panel with uniform activation force in touch sensitive surfce

1 is an exploded perspective view showing an embodiment of a touch panel according to the present invention.

FIG. 2 is a cross-sectional view of the touch panel taken along the line II-II of FIG. 1.

Figure 3 shows another embodiment of the distribution of the dot spacer of the touch panel according to the present invention.

Figure 4 shows another embodiment of the distribution of the dot spacer of the touch panel according to the present invention.

5 is a plan view of a touch panel showing a position where the pressing force is measured in the touch panel according to the present invention.

6 is an exploded perspective view of a conventional analog type touch panel.

FIG. 7 illustrates a cross-sectional view of the touch panel taken along the line VII-VII of FIG. 6.

<Brief description of symbols for the main parts of the drawings>

10. Touch panel 11. Upper board

12. Lower transparent conductive film 50. Lower substrate

52. Bottom transparent conductive film 53. Dot spacer

54a, 54b. Bottom electrode

56a, 56b. Upper electrodes 58a, 58b. Electrode Induction Line

70. Adhesive Layer 80. Cable

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a touch panel attached to an image display device such as a liquid crystal display device, and more particularly, to input data according to an image on a screen with a uniform activation force using a hand or a pen. It relates to a touch panel.

In general, input devices include a touch panel and a digitizer. According to such an input device, an input means, ie, a button displayed on a display by a hand or a pen, may be touched or contacted. It is possible to easily use the information of the image display device that is connected and electrically connected.

In addition, the touch panel used with the image display device is applied to a pen computer or a personal digital assistant, and the use thereof is being increased, and the analog resistive type, the digital resistive type, and the capacitive Various types of touch panels, such as capacitive type, saw type, and infrared type, are used.

FIG. 6 is an exploded perspective view of a conventional analog type touch panel, and FIG. 7 is a cross-sectional view of the touch panel taken along the line VII-VII of FIG. 6.

Referring to the drawings, the touch panel 100 includes an upper substrate 110, a lower substrate 150, an adhesive layer 170, and a cable 180 facing each other.

Four electrode induction lines 158, lower electrodes 154a and 154b, a transparent conductive film 152, a dot spacer 153 and upper electrodes 156a and 156b are formed on the lower substrate 150. One end of each electrode induction line 158 is electrically connected to the cable 180, and the other end thereof is connected to two lower electrodes 154a and 154b and an upper electrode 156a and 156b, respectively.

The lower electrodes 154a and 154b and the upper electrodes 156a and 156b are insulated by the insulating layer 160 to be electrically separated from each other, and the lower electrodes 154a and 154b and the upper electrodes 156a and 156b are perpendicular to each other. Are arranged in the direction.

The two lower electrodes 154a and 154b face each other and are disposed in parallel to each other, and a transparent conductive film 152 is formed therebetween.

As illustrated in FIG. 7, the dot spacers 153 are uniformly formed in the same shape at predetermined intervals on the transparent conductive film 152.

The upper substrate 110 is made of a flexible film, and a transparent conductive film 112 is coated thereon. The transparent conductive film 112 is connected to the upper electrodes 156a and 156b at its periphery.

The upper substrate 110 and the lower substrate 150 are attached to each other by the adhesive layer 170.

Looking at the operation of the touch panel 100 according to such a configuration as follows. When a point of the upper substrate 110, which is a flexible film material, is pressed by an input means such as a pen or a hand, one point of the transparent conductive films 112 and 152 formed on the upper substrate 110 and the lower substrate 150 is in contact with the upper portion. Electrodes 156a and 156b and lower electrodes 154a and 154b are energized. At this time, when the voltage value changed according to each resistance value is read out, and the control device converts the digital value according to the change in the potential difference to find the position coordinate, the contact position is measured.

However, in the touch panel 100, the gap A between the upper substrate 110 and the lower substrate 150 is usually about 100 μm, whereas the dot spacer 153 is only about 5 μm. Since 153 is uniformly arranged in the same shape on the transparent conductive film 152 of the lower substrate 150, a difference occurs in the activation force. That is, the pressing force decreases toward the center of the touch panel, but the pressing force increases relatively toward the edge of the touch panel. Herein, the activation force means the pressure at which the coordinate recognition of the touch panel is first detected.

In consideration of the fact that a relatively large pressing force is required at the periphery, the upper substrate 110 is relatively loosened, or if there is a deflection due to thermal deformation or the like at the central portion, the upper and lower substrates of the upper and lower substrates The transparent conductive films 112 and 152 may be in contact with each other, which may cause damage and malfunction of an image of the display used with the touch panel.

The present invention is devised to solve the above problems, and an object thereof is to provide a touch panel capable of operating with a constant pressing force on the front surface of the upper substrate.

In order to achieve the above object, according to an aspect of the present invention, an upper substrate having an upper transparent conductive film formed between upper electrode lines, a lower substrate having a lower transparent conductive film formed between lower electrode lines, and the upper transparent conductive film and the A touch panel including a plurality of dot spacers formed between the lower transparent conductive layers to prevent contact between upper and lower transparent conductive layers when a predetermined pressing force is not applied, wherein the dot spacers distribute the dot spacers at the periphery and the center. Alternatively, the minimum pressing force acting on the upper substrate may be 90% or more of the maximum pressing force. Here, the height of the dot spacer is gradually increased from the peripheral portion to the center portion, and the interval between the adjacent dot spacers may be constant. In addition, the cross-sectional shape of the dot spacer is circular, the diameter can be formed constant, the cross-sectional shape of the dot spacer is an ellipse, the eccentricity in one direction of the ellipse may be formed step by step from the peripheral portion to the center portion. In addition, the interval of the dot spacer may be formed to become smaller step by step from the peripheral portion to the center portion.

Hereinafter, an embodiment of a touch panel according to the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view of an embodiment of a touch panel according to the present invention, Figure 2 is a cross-sectional view taken along the line II-II of FIG.

1 and 2, the touch panel 10 includes an upper substrate 11 and a lower substrate 50 facing each other.

The upper substrate 11 is a flexible film, for example, a polymer resin material such as PET (polyethylene terephthalic acid), polycarbonate or acrylic resin, and has a predetermined thickness, for example, has a thickness of about 0.1 to 0.5 mm. A transparent conductive film 12 is applied to the lower surface of the upper substrate 11, and two upper electrodes 56a and 56b facing each other in parallel to each other are disposed at both edges thereof to be electrically connected to the transparent conductive film 12.

The lower substrate 50 has a predetermined thickness, for example, about 0.1 to 3 mm, made of glass, PET, polycarbonate, or acrylic resin.

A transparent conductive film 52 is coated on the upper surface of the lower substrate 50, and a dot spacer 53 is formed on the transparent conductive film 52.

The dot spacers 53 are disposed such that the height of each dot spacer 53 increases stepwise from the peripheral portion to the center portion so that the pressing force acting on the upper substrate 11 is uniform.

At both edges of the transparent conductive film 52, two lower electrodes 54a and 54b facing each other in parallel are arranged in a direction orthogonal to the upper electrodes 56a and 56b.

Four electrode induction lines 58a and 58b are applied to the edge of the lower substrate 50, one side of which is connected to two upper electrodes 56a and 56b and two lower electrodes 54a and 54b, respectively. The other side is connected to the cable 80, for example, a flexible printed cable (FPC) so that each electrode is electrically connected to the external control circuit.

The upper substrate 11 and the lower substrate 50 are attached to each other by an adhesive layer 70. The adhesive layer 70 may be formed by an acrylic adhesive, an acrylic resin, a double-sided adhesive tape, or the like.

When the upper substrate 11 and the lower substrate 50 are attached with a double-sided tape, a process in which the upper electrodes 56a and 56b and the lower electrodes 54a and 54b are electrically connected to an external connection circuit through the cable 80. This is as follows. If a plurality of conductive holes (not shown) are prepared in advance on the double-sided adhesive tape, and the upper and lower substrates 11 and 50 are attached to the double-sided adhesive tape, the electrode induction line 58a and the upper substrate ( The upper electrodes 56a and 56b of 10) can be electrically energized through the conduction holes formed in the double-sided adhesive tape. Accordingly, the upper electrodes 56a and 56b and the lower electrodes 54a and 54b can be connected to external control circuits through the electrode induction lines 58a and 58b and the cable 80, respectively.

3 and 4 show the touch panels 20 and 30 with particular emphasis on the dot spacers as top views of different embodiments of the arrangement of the dot spacers according to the invention. Here, the same reference numerals as in the above-described drawings indicate the same members having the same function.

Referring to FIG. 3, the dot spacers 53 are arranged to have different cross-sectional shapes of the dot spacers 53 for respective portions of the touch panel 10, and the cross-sectional shapes of the dot spacers in the periphery are circular and refer to the X axis. As it goes from the periphery to the center, it is an ellipse cross section. In addition, in this manner, it is also possible to arrange the dot spacer on the basis of the Y axis. Here, the cross-sectional shape of the dot spacer may be arranged in the same manner as the cross-sectional shape of the dot spacer.

Referring to FIG. 4, the dot spacers are arranged to be smaller stepwise by varying the distances L and L 'between adjacent dot spacers from the peripheral portion to the center portion with respect to the X axis. In addition, in this manner, it is also possible to arrange the dot spacer on the basis of the Y axis.

In the touch panel according to the present invention having the structure as described above, a method for forming a dot spacer on the transparent conductive film of the lower substrate as a screen printing technique or a thick film forming technique by photo lithography (Photo Lithography) Etc. Here, the photo lithography method is as follows.

The photoresist substrate is mainly composed of polymer, photoactive sensitizer, solvent, photosensitive compound, base resin and organic solvent. A slurry of the dot spacer is manufactured by using a photo resist.

The slurry is spin-coated to form a pattern of dot spacers as shown in FIGS. 2, 3, and 4 by drying, exposure, and development. Here, the process of coating, drying, exposure, development, etc. may be carried out under conditions that can be commonly used in the technical field of the present invention, and a detailed description thereof will be omitted.

 Looking at the operation of the touch panel according to the present invention having such a structure as follows.

The distance between the dot spacer 53 and the upper substrate 11 at the edge which is the contact portion of the upper and lower substrates 11 and 50 is relatively large compared to the center portion. For example, in the case where the heights of the electrodes 56a and 56b and the electrode induction line 58 are 10 μm and the adhesive layer is 60 μm, the distance between the upper substrate 11 and the lower substrate 50 is 80 μm. Since the height of the spacer 53 is 5 μm, a large step occurs when the peripheral portion is pressurized compared to the central portion. However, since the peripheral portion is fixed by the adhesive layer 70, the range that can be extended relative to the central portion is relatively limited compared to the central portion. To compensate for this, when the height of the dot spacer 53 increases from the periphery to the center, the elongation of the polymer resin layer of the upper substrate 11 at the periphery is increased by the height of the adjacent dot spacer 53 when pressed by the input means. By being compensated by the difference of, the transparent conductive films 12 and 52 of the upper substrate 11 and the lower substrate 50 are brought into contact with each other by a smaller pressing force than before, even though the peripheral portion has a large step. The amount of elongation increases toward the central portion, but the interference is caused by the adjacent dot spacers 53, so that the transparent conductive films 12 and 52 come into contact with each other at an unwanted portion. As a result, the touch panel 10 can be used with a uniform pressing force over the entire upper substrate 11. In addition, adjusting the spacing of the dot spacers or changing the shape of the cross section allows the touch panels 20 and 30 to operate with uniform pressing force.

Experimental Example 1

The upper transparent conductive film was coated with a thickness of 250 μs using PET having a thickness of 0.17 mm as the upper substrate, and the upper electrode was coated with a thickness of 10 μm using silver (Ag) as a main component.

The lower transparent conductive film was coated with a thickness of 200 mm using a glass having a thickness of 1.1 mm as a lower substrate, and an electrode induction line and an upper electrode were coated with a thickness of 10 μm using silver (Ag) as a main component.

On the lower transparent conductive film, the size of the dot spacer was 5 μm at the periphery and 10 μm at the periphery, and the dot spacer was enlarged from the periphery to the center by photolithography. In addition, the space | interval between adjacent dot spacers was made uniform at 1 mm in the horizontal direction, and 1 mm in the longitudinal direction.

The upper and lower substrates were attached to a double-sided tape having a thickness of 60 μm to prepare a touch panel having a size of 290 mm in the horizontal direction and 200 mm in the longitudinal direction.

The push-pull guage and the multimeter at the respective points A, B, C, D, E, F, G, H, and I as shown in FIG. 5 for the touch panel manufactured as described above. The relative pressure is measured using a multi meter and is shown in a table.

Experimental Example 2

The dot spacer was applied so as to have a height of 1 μm at the periphery, and applied so as to have a height of 5 μm at the center. And the diameter of the dot spacer was made constant at 5 micrometers.

In addition, it carried out similarly to Example 1 except this.

Experimental Example 3

The size of the dot spacer was made constant at 5 micrometers.

In the space | interval between adjacent dot spacers, the space | interval in the peripheral part was made into 3 mm at maximum and at least 1 mm in the center part.

In addition, it carried out similarly to Example 1 except this.

Comparative Example

The upper transparent conductive film was coated with a thickness of 250 μs using PET having a thickness of 0.17 mm as the upper substrate, and the upper electrode was coated with a thickness of 10 μm using silver (Ag) as a main component.

The lower transparent conductive film was coated with a thickness of 300 mm using a glass having a thickness of 1.1 mm as a lower substrate, and an electrode induction line and an upper electrode were coated with a thickness of 10 μm using silver (Ag) as a main component.

On the lower transparent conductive film, the size of the dot spacer was uniformized to 5 μm by photolithography, and the distance between adjacent dot spacers was uniform to 1 mm in the transverse direction and 1 mm in the longitudinal direction. The height of a dot spacer was also apply | coated uniformly at 5 micrometers.

The upper and lower substrates were attached to a double-sided tape having a thickness of 60 μm to prepare a touch panel having a size of 290 mm in the horizontal direction and 200 mm in the longitudinal direction.

For the touch panel manufactured as described above, the relative pressing force of each point (A, B, C, D, E, F, G, H, I) shown in FIG. 5 was measured by using a push pull gauge and a multimeter. It is shown in the table. Here, the relative pressing force means the relative pressing force when the maximum pressing force at each point in the comparative example is 100.

FIG. 5 is a plan view of a touch panel showing respective points for measuring the pressing force of the touch panels of Examples 1 to 3 and Comparative Example 1. FIG. Here, the same reference numerals as in the above-described drawings indicate the same members having the same function.

Relative pressure relative to maximum pressure Pressure Max pressing force % Difference between minimum and maximum pressure A B C D E F G H I Experimental Example 1 75 73 75 72 71 72 75 73 75 71 75 5.4 Experimental Example 2 75 73 75 72 71 72 75 73 75 71 75 5.4 Experimental Example 3 75 73 75 72 71 72 75 73 75 71 75 5.4 Comparative example 100 95 100 93 70 93 100 95 100 70 100 30

Referring to Table 1, in Experimental Examples 1 to 3, the maximum and minimum pressurization pressures showed deviations within 5.4%, whereas the comparative examples showed 30% deviations. In addition, the maximum pressing force of Experimental Examples 1 to 3 is only 75% of the maximum pressing force of the Comparative Example.

From this point of view, by the arrangement of the dot spacer according to the present invention, the touch panel according to the present invention shows that the more uniform pressing force can be operated better with less pressing force than the conventional touch panel. .

According to the touch panel according to the present invention, the following effects can be obtained. That is, when a user presses any point of the polymer resin layer of the upper substrate by an input means such as a hand or a pen while a predetermined voltage is applied to the touch panel through the flexible printed cable, By arranging dot spacers having different shapes or heights, the transparent conductive film formed on the upper substrate can contact the transparent conductive film on the lower substrate with a uniform pressing force. In addition, malfunctions or burns can be prevented from being caused by contact between the upper substrate and the lower substrate at an undesired area due to heat deformation of the upper substrate, such as a polymer resin, or deformation due to prolonged use.

Claims (6)

An upper substrate having an upper transparent conductive film formed between the upper electrode lines, a lower substrate having a lower transparent conductive film formed between the lower electrode lines, and a lower substrate formed between the upper transparent conductive film and the lower transparent conductive film, and the upper and lower substrates may be In the touch panel provided with a plurality of dot spacers to prevent the contact of the lower transparent conductive film, The dot spacer is a touch panel, characterized in that by varying the distribution of the dot spacer in the peripheral portion and the central portion, the minimum pressing force acting on the upper substrate is 90% or more of the maximum pressing force. The method of claim 1, The dot spacer is a touch panel, characterized in that the height of the dot spacer is gradually increased from the peripheral portion to the center portion. The method of claim 2, The dot spacer is a touch panel, characterized in that the interval between adjacent dot spacers are constant. The method according to claim 1 or 3, The cross-sectional shape of the dot spacer is circular, the touch panel, characterized in that the diameter is constant. The method of claim 3, The cross-sectional shape of the dot spacer is an ellipse, and the eccentricity in one direction of the ellipse is increased step by step from the peripheral portion to the center portion. The method according to claim 1 or 2, The interval between the dot spacer is smaller in step by step from the peripheral portion to the center portion.

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