WO2009049445A1

WO2009049445A1 - Capacitance type touch screen and manufacturing method thereof

Info

Publication number: WO2009049445A1
Application number: PCT/CN2007/003189
Authority: WO
Inventors: Jiqiang He; Huahong Jiang
Original assignee: Truly Semiconductors Ltd.
Priority date: 2007-10-17
Filing date: 2007-11-12
Publication date: 2009-04-23
Also published as: CN101140368A

Abstract

A capacitance type touch screen includes an upper substrate, a lower substrate and the induction blocks. There is an insulating liquid injected into a gap between the upper substrate and the lower substrate of the touch screen to control the space between the two layer substrates. A manufacturing method of the capacitance type touch screen includes: first, manufacturing a row induction block on the upper substrate, and manufacturing a column induction block on the lower substrate, then jointing the two layer substrates through a frame glue and remaining a opening; injecting the insulating liquid by way of a vacuum pumping to inject the liquid, in the end, sealing the opening through a sealing compound.

Description

Capacitive touch screen and manufacturing method thereof

The present invention relates to a touch screen, and more particularly to a capacitive touch screen. The invention also relates to a method of fabricating the capacitive touch screen.

Background technique

At present, the touch screen is an input device, which allows the user to input information directly by touch or handwriting on the surface of the display device with the touch screen, which is more friendly and convenient than the input devices such as a mouse and a keyboard, and thus is more and more widely used. On a variety of portable devices, such as mobile phones, PDAs, etc. There are many types of touch technology available. According to the type of contact used and the way to confirm the position of the contact, the touch screen can be divided into resistive, capacitive, infrared, and surface acoustic waves. With the maturity of capacitive touch screen control IC technology, the cost is reduced, and there are some unique advantages compared with other technologies, such as good durability, not easy to damage, and can be used for a long time, making the application of capacitive touch screen more and more widely. .

Referring to Figure 1, a capacitive touch screen typically includes a substrate 1 and an inductive block 2 fabricated on the substrate 1.

Referring to FIG. 2 and FIG. 3, for a sensing block 2 on the capacitive touch screen, when not touched, the sensing block and the adjacent sensing block constitute a parasitic capacitance 3, when touched, when the finger 6 or the conductor is close, the finger 6 or the conductor and The sensing block 2 and the sensing block adjacent to the sensing block 2 respectively form capacitors 4 and 5, and measure the sensing block 2, and if it is detected that the capacitance change of the sensing block 2 exceeds a certain threshold, it can be determined that there is a touch at the corresponding position of the sensing block 2 .

For a capacitive touch screen used as a button or slider, there is usually only a single layer of sensing electrodes. Referring to Figure 1, the substrate 1 and the sensing block 2 are included. ' '

For the need to determine the two-dimensional coordinates, referring to FIG. 4, the capacitive touch screen generally includes an upper substrate 11 and a row sensing block 21 fabricated on the upper substrate 11, a lower substrate 12, and a column sensing block 22 formed on the lower substrate 12, the two-layer substrate They are bonded together by the adhesive 7 with a certain gap in between. The upper and lower substrates 11, 12 are made of insulating materials such as glass, PET, and PC boards. '

For the touch screen of the double-layer substrate structure shown in FIG. 4, there is no filler between the upper and lower substrates 11, 12, which is empty, that is, mainly air, so that it is difficult to control the distance between the two substrates, When the unevenness between the two substrates occurs, referring to FIG. 7, the upper substrate 11 is bent downward, thereby causing the Newton ring to appear, and more seriously, the upper and lower substrates are brought into contact, which may result in rows and columns. The sensing block is turned on, causing the touch screen to fail. '

In addition, the existing capacitive touch screens are generally directly attached to the display device, and no conductive shielding layer is added in the middle. Referring to FIG. 5, the capacitive touch screen A of the single-layer substrate structure is directly added directly through the frame adhesive 8 or the fixed component. Display device 9. Referring to FIG. 6, the capacitive touch screen B of the double-layer substrate structure is also directly added by the frame glue 8 or other fixing components. On the display device 9, the surface of the display device generally has a certain electromagnetic interference, which may affect the signal collected by the capacitive touch screen attached thereto, and the positioning of the touch screen may be inaccurate.

Summary of the invention

The object of the present invention is to provide a capacitive touch screen which has a simple structure and can avoid occurrence of inaccurate positioning. Another object of the present invention is to provide a method of fabricating the above capacitive touch screen.

The present invention can be implemented by the following technical measures, a capacitive touch screen including an upper and a lower substrate and a sensing block, characterized in that a gap between the upper and lower substrates of the touch screen is filled with a space for controlling the distance between the two substrates. Insulating liquid. Thereby solving the problem of uneven spacing of the two layers of the substrate, avoiding the failure of the touch screen and prolonging its service life.

The insulating liquid of the present invention includes all insulating liquids having a refractive index of 1. 2 to 2.2, which may be liquid crystals or other insulating liquids. In order to increase the light transmittance of the touch screen, it is possible to fill the two substrates of the touch screen by selecting an insulating liquid having an appropriate refractive index. According to the optical principle, when light is incident on the interface between the two media, a part of the reflection will occur, and a part of the refraction will be related to the difference in refractive index between the two media. When the refractive index difference between the two media is larger, the reflection The light is stronger. Referring to FIG. 8 and FIG. 9, if there is air 10 in the touch screen box, the refractive index of the air is about 1, and when the incident light a passes through the touch screen, there is a relatively strong reflected light bl; when the insulation is filled in the box of the touch screen When the liquid 13 is such that the refractive index of the insulating liquid 13 is close to the refractive index of the substrate material and the sensing block, that is, when the refractive index is 1.2 to 2.2, the reflected light b2 is weakened, and it is good to select a liquid having an appropriate refractive index. Reduce the reflectivity of the touch screen, thereby increasing the light transmittance of the touch screen. '

The invention can be improved as follows: a transparent conductive shielding layer is further disposed on a side of the capacitive touch screen that is matched with the display device, and the conductive shielding layer disposed on the capacitive touch screen is fixedly connected to the display device; The conductive shielding layer is coupled to the ground to which the touch screen system is applied. Because the invention adds a conductive shielding layer between the capacitive touch screen and the display device, the electromagnetic interference received by the touch screen is greatly reduced, thereby ensuring accurate positioning of the touch screen.

The present invention can be modified as follows. The conductive shielding layer is disposed on a lower substrate of the capacitive touch screen, and the conductive shielding layer is fixed to the display device. The lower substrate may further be provided with an insulating substrate, and the conductive shielding layer covers the insulating substrate.

In the above method for manufacturing the capacitive touch screen, first, a row sensing block is formed on the upper substrate, a column sensing block is formed on the lower substrate, and then the two layers of the substrate are bonded by the frame glue, and an opening is left; and then the vacuum is applied. , fill the insulating liquid, and finally seal the opening with sealant.

Compared with the prior art, the invention has the following remarkable effects:

(1) The invention can well control the spacing between the upper and lower substrates by injecting an insulating liquid in the capacitive touch screen box of the double-layer substrate structure, and effectively avoids the Newton ring and prevents the two layers from contacting. Together, the touch screen fails.

(2) The present invention also provides an insulating liquid having an appropriate refractive index according to requirements, so that the touch screen can reduce the inverse of the incident light. Rate, improve the transmittance of the touch screen.

(3) The present invention can also select an insulating liquid having an appropriate dielectric constant according to requirements, so that the sensitivity of the touch panel can be used.

(4) The invention also increases the electromagnetic interference between the capacitive touch screen and the display device, thereby greatly reducing electromagnetic interference received by the touch screen, making the collected data more accurate, and avoiding that the sensing position does not correspond to the actual click position. Case. DRAWINGS

1 is a schematic structural view of a capacitive touch screen of a single-layer substrate structure;

2 is a schematic view of the capacitive touch screen of the single-layer substrate structure when the sensing block is not touched; FIG. 3 is a schematic view of the capacitive touch screen of the single-layer substrate structure when the sensing block is touched;

4 is a schematic structural view of a capacitive touch screen of a two-layer substrate structure;

5 is a schematic structural view of a capacitive touch screen of a single-layer substrate structure connected to a display device;

6 is a schematic structural view of a capacitive touch screen of a two-layer substrate structure connected to a display device;

7 is a schematic structural view of a top substrate of a capacitive touch screen of a two-layer substrate structure when bent;

FIG. 8 is a schematic diagram of light reflection when the inside of the box of the capacitive touch screen of the double-layer substrate structure is air; FIG.

9 is a schematic view showing light reflection when an insulating liquid is provided in a box of a capacitive touch screen having a two-layer substrate structure; FIG. 10 is a schematic view showing the insulating liquid filled in the capacitive touch screen box of the two-layer substrate structure of Embodiment 1; 11 is a schematic diagram of the step 2 of injecting the insulating liquid in the capacitive touch screen box of the double-layer substrate structure of Embodiment 1; FIG. 12 is a schematic diagram of the step 3 of injecting the insulating liquid in the capacitive touch screen box of the double-layer substrate structure of Embodiment 1. 13 is a schematic view showing the insulating liquid filled in the capacitive touch screen box of the double-layer substrate structure of Embodiment 2; FIG. 14 is a dielectric constant of the capacitive touch screen box of the double-layer substrate structure of Embodiment 3 being filled with a dielectric constant greater than that of FIG. Schematic diagram of an insulating liquid of 1;

Figure 15 is a schematic view showing the structure of a capacitive touch panel having a two-layer substrate structure with a conductive shielding layer connected to a display device of Embodiment 4;

Fig. 16 is a view showing the structure of a capacitive touch panel having a two-layer substrate structure in which an insulating substrate and a conductive shielding layer are provided in the embodiment 5, and a display device.

detailed description

Example 1

Embodiment 1 of the present invention, as shown in FIGS. 10 to 12, a capacitive touch panel B1 of a two-layer substrate structure includes an upper substrate 11, a lower substrate 12, and a sensing block between the upper and lower substrates 11, 12 of the touch panel. The gap is filled with an insulating liquid 13 for controlling the distance between the two substrates, which overcomes the uneven spacing between the two substrates, thereby effectively avoiding the appearance of Newton's ring. The insulating liquid 13 is a liquid crystal, and the capacitive touch screen B1 A glass substrate is used, and the material of the sensing block is indium tin oxide (ITO). Since the refractive index of the glass is about 1.52, the refractive index of the indium oxide-tin (ITO) conductive film is about 1.8, the refractive index of the liquid crystal is about 1.5, and the refractive index of air is 1, in the liquid crystal with glass and indium oxide. At the interface of the tin (ITO) conductive film, the difference in refractive index between the two layers is smaller than when the liquid crystal is not filled (the air between the two substrates), and thus the reflected light intensity is greatly reduced. Therefore, after the liquid crystal is poured, the intensity of the reflected light b2 of the incident light a can be well reduced, and the transmittance of the capacitive touch screen is increased.

The insulating liquid of the present invention is not limited thereto, and all insulating liquids having a refractive index of 1. 2 to 2.2 are also included. ' '

The above capacitive touch panel B1 is produced by vacuum filling to ensure uniform gap between the two substrates of the capacitive touch screen of the two-layer substrate structure. First, the row sensing block 21 is formed on the upper substrate 11, and the lower substrate is formed on the lower substrate. The column sensing block 22 is formed on the 12, and then the two layers of the substrate are bonded by the frame glue 8 and the opening 17 is left. Then, the insulating liquid 13 is filled by vacuum filling, and then the opening 17 is sealed by the sealing glue 18. , to avoid the outflow of the insulating liquid 13.

The specific filling process is as follows -

(1) The liquid to be filled 13 is filled in the groove of the filling tank 20;

(2) Aligning the opening 17 of the empty screen of the touch screen B1 with the groove;

(3). After placing the touch screen B1 empty box on the filling tank 20, place it in the vacuuming device 23;

(4) After the vacuum device 23 is sealed, vacuuming is performed, and after a certain period of time, the internal pressure of the touch screen B1 empty box and the vacuum device 23 is lowered to near the vacuum pressure;

(5) Then, the vacuum device 23 is started to be inflated, and the air pressure is gradually increased. At this time, since the air pressure inside the empty box of the touch screen B1 is smaller than the internal air pressure of the vacuum device 23, the insulating liquid 13 is subjected to the air pressure and starts to be injected into the empty box;

(6). When the empty box is filled with insulating liquid B, remove the empty box and seal the empty box with the sealing glue 18.

Example 2

Embodiment 2 of the present invention is different from the previous embodiment in that the capacitive touch panel B2 of the two-layer substrate structure is further provided with a spacer 16 between the upper substrate 11 and the lower substrate 12, thereby Further ensuring a uniform distance between the two substrates, the spacer 16 can be sprayed or screen printed.

Example 3

As shown in FIG. 14, the third embodiment of the present invention is different from the first embodiment in that an insulating liquid 13 is filled between the upper and lower substrates of the capacitive touch panel B3 having a two-layer substrate structure, and the dielectric constant of the insulating liquid 13 is larger than 1. Since the dielectric constants of different insulating liquids are different, the sensitivity of the touch screen may be different. Therefore, in order to achieve the purpose of adjusting the sensitivity of the touch screen, it can be realized by selecting an insulating liquid with different dielectric constants. In general, the dielectric constant of the selected insulating liquid is greater than 1. Example 4

Embodiment 4 of the present invention is as shown in FIG. 15. Different from Embodiment 1, a capacitive touch panel B4 having a two-layer substrate structure, the outer surface of the lower substrate 12 is covered with a transparent conductive shielding layer 14, a conductive shielding layer. 14 is connected to the ground of the system to which the touch screen is applied, and is fixedly connected to the liquid crystal display (LCD) 9a via the adhesive 8a. The conductive shielding layer 14 can also be fixedly mounted to the display (LCD) 9a by other fixing means.

Example 5

The fifth embodiment of the present invention is different from the previous embodiment. The capacitive touch panel B5 of the double-layer substrate structure has an insulating substrate 15a adhered to the outer surface of the lower substrate 12, which is transparent and electrically conductive. The shield layer 14 is covered on the layer of the insulating substrate 15a, and is fixedly connected to the liquid crystal display (LCD) 9a via the adhesive 8a. The insulating substrate 15a may be a transparent substrate such as PET, PC, or glass.

The embodiment described above exemplifies the present invention by taking a liquid crystal display as an example, but the scope of protection of the present invention is not limited thereto. According to the above description of the present invention, the capacitive touch screen can be integrated with any display device, such as: an electroluminescent device (ELD), a cathode ray tube (CRT), a plasma display panel (PDP), a vacuum fluorescent display ( VFD) and so on. The above-mentioned conductive shielding layer may be a material which can form a transparent electrode layer such as indium tin oxide (ITO) or indium-zinc oxide (yttrium oxide). The above-mentioned substrate of the capacitive touch screen includes all transparent materials such as glass, PET, and PC. The material of the above-mentioned sensing block includes a material such as indium tin oxide (ITO) or indium-zinc oxide (yttrium oxide) which can form a transparent 3⁄4 electrode layer.

Claims

Rights request

A capacitive touch panel comprising an upper and a lower substrate and a sensing block, characterized in that an insulating liquid for controlling the distance between the two substrates is filled in a space between the upper and lower substrates of the touch screen.

2. A capacitive touch screen according to claim 1, wherein said insulating liquid has a refractive index of 1.2 to 2.2, which is close to a refractive index of said substrate material and said sensing block.

3. A capacitive touch screen according to claim 2, wherein said insulating liquid is a liquid crystal having a refractive index of 1.5.

The capacitive touch screen according to claim 1 or 2, wherein a side of the capacitive touch screen that is matched with the display device is further provided with a transparent conductive shielding layer, and the capacitive touch screen is The conductive shielding layer is fixedly connected to the display device; the conductive shielding layer is connected to the ground to which the touch screen system is applied.

5. A capacitive touch screen according to claim 4, wherein the conductive shielding layer is disposed on an outer surface of the lower substrate of the capacitive touch screen, and the conductive shielding layer is fixed to the display device.

The capacitive touch screen according to claim 5, wherein the outer surface of the lower substrate of the capacitive touch screen is further provided with an insulating substrate, and the conductive shielding layer covers the insulating substrate of the layer. on.

7. A capacitive touch screen according to claim 4, wherein the material of the conductive shielding layer is indium tin oxide (yttrium), indium-zinc oxide (yttrium).

8. The method of manufacturing a capacitive touch screen according to claim 1, wherein: firstly, a row sensing block is formed on the upper substrate, a column sensing block is formed on the lower substrate, and then the two layers of the substrate are bonded by the frame glue, and left Opening; then vacuuming the liquid, filling the insulating liquid, and finally sealing the opening with a sealing glue.

9. The method of manufacturing a capacitive touch device according to claim 8, wherein: the body filling process is as follows:

(1). Fill the groove of the filling tank with the liquid to be filled;

(2). Align the mouth of the touch screen empty box with the groove;

(3) . After placing the touch screen empty box on the filling tank, place it in the vacuuming device together;

(4) After the vacuum equipment is sealed, vacuum is applied until the air pressure inside the vacuum box and the vacuum device is lowered to near the vacuum pressure;

(5) Then, the vacuum device is inflated, and the air pressure is gradually increased, so that the air pressure inside the touch screen empty box is smaller than the internal air pressure of the vacuum device, and the insulating liquid is subjected to the air pressure to start injecting into the empty box;

(6). When the empty box is filled with insulating liquid, take out the empty box and seal the opening of the empty box with sealing glue.