TW201515024A - High sensitivity capacitive touch device - Google Patents

Abstract

A high sensitivity capacitive touch device comprises vertically stacked sensing layers, a protective layer and a high dielectric material film. The high dielectric material film is coated to form on the sensing layers or on the surface of the protective layer, increasing the capacitance value variance caused by an object touching the touch device, thereby increasing higher sensitivity.

Description

High sensitivity capacitive touch element

The present invention relates to a capacitive touch element, and more particularly to a capacitive touch element for improving sensitivity.

The operation principle of the capacitive touch technology is to change the capacitance value of the touch sensor at the contact by contacting the capacitive touch element (such as a finger or other conductor), and positioning the contact via the controller. position. Since the sensing layer of the touch element is made of a conductor, the insulating layer is usually covered with an insulating material as a protective layer to protect the sensing layer. The material of the protective layer is usually made of plastic, glass, resin, and other tough materials.

FIG. 1 is a schematic diagram of a finger contacting a capacitive touch element. The capacitive touch element 10 is composed of a sensing layer 12 and a protective layer 14 covered thereon. The sensing layer 12 is a conductor, so that there is a basic capacitance C _Base between it and the ground GND. The protective layer 14 is an insulator. When the finger 16 touches the protective layer 14, since the human body belongs to the conductor and has a potential equal to the ground, another capacitance C _Press will appear between the sensing layer 12 and the finger 16. In this case, the sensing layer 12 can be regarded as the upper electrode plate of the capacitor C _Press , the finger 16 can be regarded as the lower electrode plate of the capacitor C _Press and grounded, and the intermediate protective layer 14 is the dielectric layer of the capacitor C _Press . Therefore, when the finger 16 touches the protective layer 14, the capacitance C _Press is in parallel with the basic capacitance C _{Base of the} sensing layer 12, resulting in an increase in the overall capacitance value.

FIG. 2 is a voltage waveform diagram generated by the controller charging and discharging the touch element 10 of FIG. 1 . It is assumed that the touch element 10 is charged and discharged with a constant current I for a certain period of time T. When the finger 16 does not touch the touch element 10, the generated voltage signal is a waveform 18; when the finger 16 contacts the touch element 10, the total As the capacitance increases, the resulting voltage signal becomes waveform 20. After the voltage signal passes through the low-pass filter, the DC level is obtained. It is assumed that the DC level 22 of the waveform 18 is V, and the DC level 24 of the waveform 20 is V-ΔV. Since the constant current I and the charge and discharge time T are fixed, the total charge Q is the same regardless of whether the finger 16 contacts the touch element 10, The capacitance of the basic capacitor C _Base is the pF level, and the capacitance of the capacitor C _Press is the fF level. The larger the ΔV/V, the easier it is to detect the voltage change amount ΔV, which is the so-called sensitivity improvement. It can be known from Equation 1 that the basic capacitance C _Base becomes smaller or the capacitance C _Press becomes larger to increase the sensitivity. The basic capacitance C _Base can be reduced by the skill of the circuit layout. The capacitor C _Press is composed of the sensing layer 12, the finger 16 and the protective layer 14. The capacitance of the parallel plate capacitor is C=ε _γ ε _O A/d, where ε _γ ε _O is the dielectric of the dielectric layer. Constant, A is the area of the two electrode plates, and d is the distance between the two electrode plates. As can be seen from Equation 2, in order to increase the size of the C _Press , the distance between the sensing layer 12 and the finger 16 can be reduced, the area of the sensing layer 12 can be increased, or the protective layer 14 having a high dielectric constant can be selected.

A conventional method for improving the sensitivity of a capacitive touch element is to reduce the basic capacitance C _{Base of the} sensing layer 12 by using a circuit wiring technique, and to use a protective layer 14 having a large dielectric constant (for example, a dielectric constant of glass is about 5 to 7). ), a thin protective layer 14 or the like is used. However, the redesign of the sensing layer 14 is cumbersome, and the improvement effect is less significant due to the difference in capacitance levels. The thickness of the protective layer 14 may sometimes not be changed due to the protection requirements and the specifications of the equipment used.

One of the objects of the present invention is to provide a simple, low-cost solution to improve the sensitivity of capacitive touch elements.

One of the objects of the present invention is to provide a high-sensitivity capacitive touch element and a process thereof.

In accordance with the present invention, a high sensitivity capacitive touch element includes a sensing layer, a high dielectric material film on the sensing layer, and a protective layer over the high dielectric material film.

According to the present invention, a high-sensitivity capacitive touch element includes a sensing layer, a protective layer on the sensing layer, and a high dielectric material film on the protective layer.

According to the present invention, a high-sensitivity capacitive touch element includes a sensing layer, a first high dielectric material film on the sensing layer, a protective layer on the first high dielectric material film, and a second high A dielectric material film is on the protective layer.

According to the present invention, a process for a high-sensitivity capacitive touch device includes preparing a sensing layer and a protective layer, forming a high dielectric material film on the sensing layer, and attaching the protective layer to the high dielectric material. On the membrane.

According to the present invention, a process for a high-sensitivity capacitive touch device includes preparing a sensing layer and a protective layer, forming a high dielectric material film on the protective layer, and attaching the high dielectric material film to the sensing On the floor.

According to the present invention, a process for a high-sensitivity capacitive touch device includes preparing a sensing layer and a protective layer, forming a high dielectric material film on the protective layer, and attaching the protective layer to the sensing layer.

According to the present invention, a process for a high-sensitivity capacitive touch device includes preparing a sensing layer and a protective layer, attaching the protective layer to the sensing layer, and forming a high dielectric material film on the protective layer.

According to the present invention, a process for a high-sensitivity capacitive touch device includes preparing a sensing layer and a protective layer, forming two high dielectric material films on upper and lower surfaces of the protective layer, and forming the two high dielectric material films One of them is attached to the sensing layer.

According to the present invention, a process for a high-sensitivity capacitive touch device includes preparing a sensing layer and a protective layer, forming a first high dielectric material film on the sensing layer, and a second high dielectric material film in the protection And coating the protective layer on the first high dielectric material film.

The step of forming the high dielectric material film may be performed in a vacuum or non-vacuum environment using physical deposition, chemical deposition, coating, chemical replacement, immersion or spraying, and heat treatment may be performed as needed, or different additions may be made. Solvents and compounds.

10‧‧‧Capacitive touch elements

12‧‧‧Sense layer

14‧‧‧Protective layer

16‧‧‧ fingers

18‧‧‧ Waveform of voltage signal

20‧‧‧ Waveform of voltage signal

22‧‧‧ DC level of voltage signal

24‧‧‧ DC signal level of voltage signal

26‧‧‧High dielectric material film

28‧‧‧High dielectric material film

30‧‧‧Capacitive touch elements

32‧‧‧Gold Fingers

1 is a schematic diagram of a finger touching a capacitive touch element; FIG. 2 is a voltage waveform diagram generated by a controller for charging and discharging the touch element of FIG. 1; FIG. 3 is a first embodiment of the present invention; Figure 4 is a second embodiment of the present invention; Figure 5 is a third embodiment of the present invention; Figure 6 is a fourth embodiment of the present invention; Figure 7 is a fifth embodiment of the present invention; Sixth embodiment; FIG. 9 is an experiment for testing the sensitivity of the capacitive touch element of the present invention; and FIG. 10 is the amount of inductance generated by the X-axis sensing line and the Y-axis sensing line in the experiment of FIG.

3 is a first embodiment of the present invention in which the sensing layer 12 and the protective layer 14 are prepared, a high dielectric material film 26 is formed on the sensing layer 12, and then the protective layer 14 is pasted on the high dielectric material film 26.

4 is a second embodiment of the present invention, in which the sensing layer 12 and the protective layer 14 are prepared, a high dielectric material film 26 is formed on the protective layer 14, and the protective layer 14 is flipped over, and the high dielectric material film 26 is pasted on On the sensing layer 12.

5 is a third embodiment of the present invention. The sensing layer 12 and the protective layer 14 are prepared, and a high dielectric material film 28 is formed on the protective layer 14, and the protective layer 14 is attached to the sensing layer 12.

6 is a fourth embodiment of the present invention. The sensing layer 12 and the protective layer 14 are prepared. After the protective layer 14 is attached to the sensing layer 12, a high dielectric material film 28 is formed on the protective layer 14.

7 is a fifth embodiment of the present invention, in which the sensing layer 12 and the protective layer 14 are prepared, and two high dielectric material films 26 and 28 are formed on the upper and lower surfaces of the protective layer 14, and the high dielectric material film 26 is pasted. On the sensing layer 12.

8 is a sixth embodiment of the present invention. The sensing layer 12 and the protective layer 14 are prepared to form a first high dielectric material film 26 on the sensing layer 12 and a second high dielectric material film 28 on the protective layer 14. The protective layer 14 is then pasted on the first high dielectric material film 26.

When the object touches the capacitive touch element of the present invention, a high dielectric material film 26 or two high dielectric material films 26 and 28 are present between the object and the sensing layer 12, so that the capacitance value caused by the touch changes. The amount will increase and the sensitivity will increase.

The sensing layer 12, the protective layer 14, and the high dielectric material films 26 and 28 may be light transmissive or non-translucent.

There are many materials that can form the high dielectric material films 26 and 28, such as titanium dioxide (TiO ₂ ). Titanium dioxide has certain properties that make it suitable for a wide variety of applications. For example, titanium dioxide has a strong absorption in the ultraviolet region, so it can be used for UV protection products; titanium dioxide has a bandgap that can be used as a photocatalyst; titanium dioxide with a nanostructure is hydrophobic and can be used for self-cleaning or protection. On the fog glass; titanium dioxide has a high refractive index, and can be used for mirrors with optical design; titanium dioxide has a dielectric constant of 50 to 70, which can greatly increase the size of C _Press ; in the field of semiconductors, titanium dioxide has been extensively studied to replace Cerium oxide is expected to reduce leakage more effectively; titanium dioxide has high hardness and is therefore scratch resistant; titanium dioxide itself is advantageous for post-processing; titanium dioxide is stable in physical and chemical properties; titanium dioxide is not toxic. The high dielectric material films 26 and 28 made of titanium dioxide may be in the form of crystal, polycrystalline and amorphous, and have a thickness of Å to μm. The method of fabrication includes physical deposition, chemical deposition, coating, chemical replacement, It is plated on the sensing layer 12 or the protective layer 14 by dipping, spraying, or the like. In order to obtain a good coverage and stable titanium dioxide film, the process of forming the high dielectric material films 26 and 28 can be performed in a vacuum or non-vacuum environment, and heat treatment is required as needed, or different solvents and compounds are added, and physical A titanium dioxide film is obtained after a chemical or chemical reaction.

9 is an experiment for testing the sensitivity of the capacitive touch element of the present invention, wherein the sensing layer 12 of the capacitive touch element 30 has an X-axis sensing line and a Y-axis sensing line, and the titanium dioxide is plated on the sensing layer 12 to form a high dielectric. The material film 26 has a protective layer 14 thereon, and the gold finger 32 is used to touch the capacitive touch element 30. Figure 10 is the amount of inductance (ADC) generated by the X-axis sensing line and the Y-axis sensing line in the experiment of Figure 9. Table 1 below lists the measured inductances of the X-axis and Y-axis lines when the thickness of the uncoated high dielectric film and the high dielectric film is 160 Å, 320 Å, 640 Å, and 960 Å. Referring to FIG. 10 and Table 1, when the gold finger 32 does not contact the capacitive touch element 30, the sensing amounts of the X-axis sensing line and the Y-axis sensing line are all 10; when the gold finger 32 contacts the capacitive touch element 30, The X-axis sensing line X10 of the contact is 108, 112, 93, 117, 163 when the thickness of the uncoated high dielectric film and the high dielectric film is 160 Å, 320 Å, 640 Å, and 960 Å, respectively. The inductance of the Y-axis sensing line Y7 of the contact is 127, 136, 105, 125, 167. It is apparent from the graph of FIG. 10 that the high dielectric material film greatly increases the amount of inductance of the capacitive touch element, that is, increases its sensitivity.

The high dielectric material films 26 and 28 do not affect the protection of the sensing layer 12 by the protective layer 14, and the thickness thereof is negligible with respect to the thickness of the protective layer 14, and thus does not affect the specification limits of the device.

12‧‧‧Sense layer

14‧‧‧Protective layer

26‧‧‧High dielectric material film

30‧‧‧High-sensitivity capacitive touch elements

32‧‧‧Gold Fingers

Claims (24)

A high-sensitivity capacitive touch element includes: a sensing layer; a high dielectric material film on the sensing layer; and a protective layer on the high dielectric material film. The high-sensitivity capacitive touch element of claim 1, wherein the high dielectric material film is translucent. The high-sensitivity capacitive touch element of claim 1, wherein the high dielectric material film comprises titanium dioxide. The high-sensitivity capacitive touch element of claim 1, wherein the high dielectric material film is non-transparent. The high-sensitivity capacitive touch element of claim 1, wherein the protective layer is translucent. The high-sensitivity capacitive touch element of claim 1, wherein the protective layer is non-transparent. The high-sensitivity capacitive touch element of claim 1, wherein the sensing layer is translucent. The high-sensitivity capacitive touch element of claim 1, wherein the sensing layer is non-transparent. A high-sensitivity capacitive touch element includes: a sensing layer; a protective layer on the sensing layer; and a high dielectric material film on the protective layer. The high-sensitivity capacitive touch element of claim 9, wherein the high dielectric material film is translucent. The high-sensitivity capacitive touch element of claim 9, wherein the high dielectric material film comprises titanium dioxide. The high-sensitivity capacitive touch element of claim 9, wherein the high dielectric material film has a non-transparent Sex. The high-sensitivity capacitive touch element of claim 9, wherein the protective layer is translucent. The high-sensitivity capacitive touch element of claim 9, wherein the protective layer is non-transparent. The high-sensitivity capacitive touch element of claim 9, wherein the sensing layer is translucent. The high-sensitivity capacitive touch element of claim 9, wherein the sensing layer is non-transparent. A high-sensitivity capacitive touch element comprising: a sensing layer; a first high dielectric material film on the sensing layer; a protective layer on the first high dielectric material film; and a second high dielectric A material film is on the protective layer. The high-sensitivity capacitive touch element of claim 17, wherein the high dielectric material film is translucent. The high-sensitivity capacitive touch element of claim 17, wherein the high dielectric material film comprises titanium dioxide. The high-sensitivity capacitive touch element of claim 17, wherein the high dielectric material film is non-transmissive. The high-sensitivity capacitive touch element of claim 17, wherein the protective layer is translucent. The high-sensitivity capacitive touch element of claim 17, wherein the protective layer is non-transparent. The high-sensitivity capacitive touch element of claim 17, wherein the sensing layer is translucent. The high-sensitivity capacitive touch element of claim 17, wherein the sensing layer is non-transmissive.