KR20080054187A - Capacitive type tactile sensor and method for manufacturing the same - Google Patents

Abstract

A capacitive tactile sensor and a manufacturing method thereof are provided to measure contact position and force at the same time by applying a sine wave to transparent electrodes to measure an amplitude change and detecting a capacitance change between the transparent electrodes from the measured amplitude change. A capacitive tactile sensor includes upper and lower substrates(63,61), a plurality of lower transparent electrodes(62), a spacer(66), upper transparent electrodes(64), and a transparent insulating layer(65). The lower transparent electrodes are patterned on the upper surface of the lower substrate. The dome-shaped spacer is formed around the lower transparent electrode on the lower substrate. The upper transparent electrodes are patterned on the lower surface of the upper substrate in correspondence to the lower transparent electrodes. The transparent insulating layer is formed on the upper part of the lower transparent electrode or the lower part of the upper transparent electrode so that the upper and lower transparent electrodes are not electrically connected to each other. The upper and lower substrates are bonded by an adhesive(67) so that the upper and lower transparent electrodes face each other with an air gap.

Description

CAPACITIVE TYPE TACTILE SENSOR AND METHOD FOR MANUFACTURING THE SAME}

1 is an explanatory diagram for explaining a general touch capacitive key input device.

2 is an explanatory diagram for explaining a key input device of a general pressure resistive film type.

3 is a conceptual diagram of a capacitive touch screen configured in a matrix form.

Figure 4 is a cross-sectional view showing a capacitive tactile sensor according to an embodiment of the present invention.

5a to 5f are sequential process cross-sectional views showing a capacitive tactile sensor manufacturing method according to an embodiment of the present invention.

6 is a cross-sectional view showing a capacitive tactile sensor according to another embodiment of the present invention.

7a to 7f are sequential process cross-sectional views showing a capacitive tactile sensor manufacturing method according to another embodiment of the present invention.

8 is a circuit diagram illustrating an example of a tactile sensor module.

<Explanation of symbols for main parts of the drawings>

41: lower substrate

42: lower transparent electrode

43: upper substrate

44: upper transparent electrode

45: insulation layer

46: spacer

47: adhesive

48: air gap

The present invention relates to a capacitive tactile sensor and a manufacturing method thereof. More particularly, the present invention relates to a capacitive tactile sensor and a method of manufacturing the same. The present invention relates to a tactile tactile sensor and a manufacturing method thereof.

In general, a device such as a mobile phone, a personal digital assistant (PDA), a notebook computer, a game machine, a navigation device, or the like uses a data input device to select and input a desired function or to input data. In particular, a data input device is roughly classified into a keypad method (including a keyboard) for inputting corresponding data by pressing a key with a finger and a touch input device such as a touch pad that recognizes the data by lightly touching the contact surface.

Among them, the recognition method used in the touch input device (touch pad) is as follows.

1) Contact Capacitive Method: As shown in FIG. 1, the capacitive method detects X and Y on an ITO metal layer 12 deposited on a film 11 made of film, plastic, or glass. In the state where the dragon signal is applied, the position is detected by calculating the magnitude of the changed capacitance when a pen or finger contacts the insulating layer 13 formed on the transparent electrode 12.

2) Pressure resistive film method: As shown in FIG. 2, the upper substrate 24 and the lower substrate 23 made of film, plastic, and glass coated with the transparent electrodes 21 and 22 are shown in FIG. Is formed by bonding the transparent electrodes 21 and 22 to face each other with a dot spacer 25 therebetween. The electrical signal for position detection is applied onto one of the transparent electrodes 21 formed as described above, and the transparent electrode 21 of the upper substrate 24 is connected to the transparent electrode 22 of the lower substrate 23 by a finger or a pen. When contacted, the electrical signal is detected at the opposite transparent electrode 22. At this time, the position is determined using the magnitude of the detected electrical signal.

However, in case of a touch screen used in a mobile phone or various monitors, only one location information is detected and the contact information cannot be detected when two or more contacts are made at the same time. Due to the limited number of keys, the input method has limitations, and there is a disadvantage in that a complicated key input operation is required for various information input.

In particular, in the case of a touch pad using a pressure resistive membrane, contact position information and pressure sensing (line thickness, three-dimensional representation, perspective, color change, depth change) are possible, but the spatial resolution is lowered and the contact area There is a disadvantage in that only one position information and pressure information value are detected regardless. In addition, when the contact is made in two or more at the same time there is a disadvantage that can not detect the position information and pressure information.

Recently, in order to detect location information when two or more contacts are made simultaneously, a capacitive touch screen is manufactured and used in a matrix form as shown in FIG. 3.

However, since the unit sensor changes the signal related to the capacitance depending on the contact, there is almost no range of contact force, and it is used as an ON / OFF switch only for contact. There is a limitation in requesting information.

SUMMARY OF THE INVENTION An object of the present invention for solving the problems according to the prior art is to form each transparent electrode so as not to be in contact with each other with an air gap therebetween on the substrate, and to face each other after applying a sine wave The present invention provides a capacitive tactile sensor and a method of manufacturing the same, by detecting a change in amplitude and measuring capacitance change therefrom to simultaneously measure contact force as well as contact force.

The capacitive tactile sensor according to an aspect of the present invention for solving the technical problem is an upper, lower substrate, a plurality of lower transparent electrodes patterned on the lower substrate, and the lower transparent electrode on the lower substrate A dome-shaped spacer formed around the upper substrate, an upper transparent electrode patterned on the lower portion of the upper substrate to correspond to the lower transparent electrode, and an upper portion of the lower transparent electrode so that the lower transparent electrode and the upper projection electrode are not electrically contacted Or an insulating layer formed below the upper transparent electrode, wherein the upper substrate and the upper substrate are bonded by an adhesive to maintain the air gap so that the upper transparent electrode and the lower transparent electrode face each other and are spaced a predetermined distance apart. A contact position according to a change in capacitance between the lower transparent electrode and the upper transparent electrode; Configured to sense contact force.

In addition, the capacitive tactile sensor manufacturing method according to an aspect of the present invention comprises the steps of depositing a transparent electrode material on the upper substrate, patterning the transparent electrode material to form a plurality of upper transparent electrodes, the lower substrate Depositing a transparent electrode material on the substrate, patterning the transparent electrode material to form a plurality of lower transparent electrodes so as to correspond to the upper transparent electrodes, and selectively insulating layers on a surface of the upper transparent electrode or the lower transparent electrode Forming a plurality of spacers having a dome shape around the lower transparent electrode of the lower substrate, and the upper transparent electrode and the lower transparent electrode are opposed to each other and spaced apart by a predetermined distance to maintain the air gap. And bonding the upper substrate and the lower substrate through an adhesive.

According to another aspect of the present invention, a capacitive tactile sensor includes an upper and a lower substrate, a plurality of lower transparent electrodes patterned at regular intervals on the lower substrate, and an adhesive on the lower substrate and bonded to the lower substrate. The lower substrate including an upper substrate having a trench formed on a lower surface thereof to receive an air gap between the lower substrate and an upper transparent electrode patterned on the surface of the upper substrate so as to correspond to the lower transparent electrode; It is configured to detect the contact position and the contact force according to the change in capacitance between the transparent electrode and the upper transparent electrode.

According to another aspect of the present invention, there is provided a method of manufacturing a capacitive tactile sensor, depositing a transparent electrode material on a lower substrate, patterning the transparent electrode material to form a plurality of lower transparent electrodes, and transparent to an upper substrate. Depositing an electrode material, patterning the transparent electrode material to form a plurality of upper transparent electrodes corresponding to the lower transparent electrodes, and etching the lower surface of the upper substrate in the region where the upper transparent electrodes are formed Forming a plurality of trenches, and forming an air gap by the trench by bonding the lower substrate and the upper substrate through an adhesive so that the lower transparent electrode is accommodated in the trench and corresponds to the upper transparent electrode. It comprises a step.

The invention will become more apparent through the preferred embodiments described below with reference to the accompanying drawings. Hereinafter will be described in detail to enable those skilled in the art to easily understand and reproduce through embodiments of the present invention.

4 is a cross-sectional view illustrating a capacitive tactile sensor according to an exemplary embodiment of the present invention, wherein the lower substrates 63 and 61 and the plurality of lower transparent electrodes 62 are patterned on the lower substrate 61. ), A dome-shaped spacer 66 formed around the lower transparent electrode 62 on the lower substrate 61, and a lower transparent electrode 62 below the upper substrate 63. Insulation formed above the lower transparent electrode 62 or below the upper transparent electrode 64 so that the patterned upper transparent electrode 64 and the lower transparent electrode 62 and the upper projection electrode 64 are not in electrical contact with each other. Layer 65.

According to a characteristic aspect of the present invention, the upper substrate 63 and the lower substrate 61 may form an air gap 68 such that the upper transparent electrode 64 and the lower transparent electrode 62 face each other and are spaced a predetermined distance apart. It is bonded by an adhesive 67 to hold, and configured to measure the contact position and the contact force according to the change in capacitance between the lower transparent electrode 62 and the upper transparent electrode 64.

The upper substrate 63 and the lower substrate 61 preferably use a polymer film (polyimide film, polyester film) or a glass (glass) substrate, and the reason for using the polymer film polyimide film as a substrate is flexible. This is because it has excellent electrical, thermal, mechanical and physical / chemical properties.

In addition, the lower transparent electrode 62 and the upper transparent electrode 64 may be made of indium tin oxide (ITO) or carbon nanotube (CNT), but preferably, carbon nanotube (CNT). Is made of.

5A through 5F are cross-sectional views sequentially illustrating a method of manufacturing a capacitive tactile sensor according to an exemplary embodiment of the present invention.

First, as illustrated in FIG. 5A, a transparent electrode material 72 is deposited on the upper substrate 71, and as illustrated in FIG. 5B, the transparent electrode material 72 is patterned to form a plurality of upper transparent electrodes 72a. To form.

Sputtering may be used as a method of depositing the transparent electrode material 72, and indium tin oxide (ITO) or carbon nanotube (CNT) may be used as the upper transparent electrode material 72. Although it can be used, it is preferable to use CNT (Carbon Nanotube) which is superior to ITO and inexpensive.

Subsequently, the transparent electrode material 74 is deposited on the lower substrate 73 as shown in FIG. 5C, and the transparent electrode material 74 is patterned as shown in FIG. 5D to correspond to the upper transparent electrode. The lower transparent electrode 74a is formed.

Then, as illustrated in FIG. 5E, the insulating layer 75 is selectively formed on the surface of the lower transparent electrode 74a, and then a plurality of domes are formed around the lower transparent electrode 74a of the lower substrate 73. Spacers 76 are formed.

At this time, in one embodiment of the present invention, but the insulating layer 75 is formed on the lower transparent electrode 74a, it can be changed to form an insulating layer on the surface of the upper electrode 71 through another embodiment.

Subsequently, the upper surface of the transparent electrode 72a and the lower transparent electrode 74a face each other and are spaced a predetermined distance to maintain the air gap 78. To cement through.

As described above, according to the capacitive tactile sensor manufactured according to the exemplary embodiment of the present invention, the upper and lower electrodes are electrically separated by an insulating layer, and the capacitance changes as the distance between the electrodes changes. .

That is, the capacitance between the electrodes changes due to the pressing force on the upper substrate. To detect this, a sine wave is applied to each electrode, and then the amplitude change is measured to detect the capacitance change between the electrodes. Rather, the contact force can be measured simultaneously.

6 is a cross-sectional view illustrating a capacitive tactile sensor according to another embodiment of the present invention, and includes a lower substrate 81 and a plurality of lower transparent electrodes 82 patterned on the lower substrate 81 at predetermined intervals. ) And a lower surface of the lower substrate 81 to be adhered to the lower substrate 81 through an adhesive 87 and to receive the lower transparent electrode 82 and form an air gap 86 therebetween. An upper substrate 83 having a trench 85 formed therein and an upper transparent electrode 84 patterned on a surface of the upper substrate 83 to correspond to the lower transparent electrode 81. 82) and the contact position and the contact force according to the change in capacitance between the upper transparent electrode 84.

The upper substrate 83 and the lower substrate 81 preferably use a polymer film (polyimide film, polyester film) or glass (glass) substrate, and the reason for using the polymer film polyimide film as a substrate is flexible. This is because it has excellent electrical, thermal, mechanical and physical / chemical properties.

In addition, the lower transparent electrode 82 and the upper transparent electrode 84 may be made of indium tin oxide (ITO) or carbon nanotube (CNT), but preferably CNT (carbon nanotube). Is done.

7A to 7F are sequential process cross-sectional views illustrating a capacitive tactile sensor manufacturing method according to another exemplary embodiment of the present invention.

First, as illustrated in FIG. 7A, a transparent electrode material 92 is deposited on the lower substrate 91, and the transparent electrode material 92 is patterned as shown in FIG. 7B to form a plurality of lower transparent electrodes 92a. To form.

Subsequently, a transparent electrode material 94 is deposited on the upper substrate 93 as shown in FIG. 7C, and the transparent electrode material 94 is patterned as shown in FIG. 7D to form the lower transparent electrode 92a. A plurality of corresponding upper transparent electrodes 94a is formed.

Then, as illustrated in FIG. 7F, a plurality of trenches 95 are formed by etching the lower surface of the upper substrate 93 in the region where the upper transparent electrode 94a is formed.

The etching of the lower surface of the upper substrate 93 to form a plurality of trenches 95 may be performed by wet etching using potassium hydroxide (KOH) aqueous solution.

Thereafter, the lower transparent electrode 92a is accommodated in the trench 95 to bond the lower substrate 91 and the upper substrate 93 through the adhesive 96 so as to correspond to the upper transparent electrode 94a. An air gap 97 is formed by the trench 95.

Sputtering may be used as the method of depositing the upper transparent electrode material 94 and the lower transparent electrode material 92, and the indium tin oxide may be used as the upper transparent electrode material 94 and the lower transparent electrode material 92. ITO: Induim Tin Oxide (CTO) or carbon nanotubes (CNT: Carbon Nanotubes) may be used, but preferably, CNTs (Carbon Nanotubes) having better adhesion and lower cost than ITO are used.

Figure 8 is a circuit diagram showing an example of the tactile sensor module according to the present invention, the input terminal or output terminal is connected to the upper and lower electrodes of the matrix form, respectively, the voltage of the sine wave is applied to the input terminal, the output of the output terminal A peak detector connected to the negative input terminal of the analog amplifier OPAMP, the positive input terminal of the analog amplifier OPAMP is grounded, and a peak detector for detecting the amplitude peak value of the output voltage at the output terminal of the analog amplifier OPAMP. 100 is connected.

The output Vout value of the analog amplifier OPAMP is shown in Equation 1 below.

Accordingly, when a sine wave is applied to the input terminal, the amplitude changed according to the capacitance between each of the upper and lower electrodes is amplified to a predetermined level by an analog amplifier (OPAMP) of the output terminal, and the amplified signal causes the peak detector 100 to Since it is detected through the above, by detecting the capacitance changing between the upper and lower parts from the amplitude peak value, not only the touch (contact) position of the sensor but also the force (contact force) can be detected.

As described above, according to the present invention, the transparent electrodes are patterned so as not to be in electrical contact with each other on the upper and lower substrates, and the transparent electrodes of the upper and lower substrates are bonded to each other so as to form an air gap therebetween. By applying a sinusoidal wave to detect the change in capacitance from the peak value of the amplitude detected to measure the contact force as well as the contact position, it is possible to enable various information input.

Although the present invention has been described with reference to the accompanying drawings, it will be apparent to those skilled in the art that many different and obvious modifications are possible without departing from the scope of the invention from this description. Therefore, the scope of the invention should be construed by the claims described to include many such variations.

Claims (11)

Upper and lower substrates 63 and 61, A plurality of lower transparent electrodes 62 patterned on the lower substrate 61; A dome-shaped spacer 66 formed around the lower transparent electrode 62 on the lower substrate 61; An upper transparent electrode 64 patterned to correspond to the lower transparent electrode 62 under the upper substrate 63; It includes a transparent insulating layer 65 formed on the lower transparent electrode 62 or the lower transparent electrode 64 so that the lower transparent electrode 62 and the upper transparent electrode 64 is not in electrical contact. , The upper substrate 63 and the lower substrate 61 are bonded by an adhesive 67 to maintain the air gap 68 so that the upper transparent electrode 64 and the lower transparent electrode 62 face each other and are spaced a predetermined distance apart. Became, Capacitive tactile sensor, characterized in that configured to detect the contact position and the contact force in accordance with the change in capacitance between the lower transparent electrode 62 and the upper transparent electrode (64). The method of claim 1, The lower transparent electrode 62 and the upper transparent electrode 64 is capacitive tactile sensor, characterized in that made of indium tin oxide (ITO) or carbon nanotubes (CNT). Depositing a transparent electrode material on the upper substrate; Patterning the transparent electrode material to form a plurality of upper transparent electrodes; Depositing a transparent electrode material on the lower substrate; Patterning the transparent electrode material to form a plurality of lower transparent electrodes to correspond to the upper transparent electrodes; Selectively forming an insulating layer on a surface of the upper transparent electrode or the lower transparent electrode; Forming a plurality of spacers having a dome shape around the lower transparent electrode of the lower substrate; And bonding the upper substrate and the lower substrate through an adhesive so that the upper transparent electrode and the lower transparent electrode face each other and are spaced a predetermined distance apart to maintain an air gap. The method of claim 3, wherein The transparent electrode material is indium tin oxide (ITO), characterized in that the capacitive tactile sensor manufacturing method. The method of claim 3, wherein The transparent electrode material is a carbon nanotube (CNT) capacitive type tactile sensor manufacturing method characterized in that the. The lower substrate 81, A plurality of lower transparent electrodes 82 patterned at predetermined intervals on the lower substrate 81; A trench on the lower surface of the lower substrate 81 is bonded to the lower substrate 81 so as to receive the lower transparent electrode 82 and form an air gap 86 between the lower substrate 81. An upper substrate 83 on which 65 is formed, An upper transparent electrode 84 patterned on a surface of the upper substrate 83 so as to correspond to the lower transparent electrode 82; Capacitive tactile sensor, characterized in that configured to measure the contact position and the contact force in accordance with the change in capacitance between the lower transparent electrode (82) and the upper transparent electrode (84). The method of claim 6, The lower transparent electrode 82 and the upper transparent electrode 84 is capacitive tactile sensor, characterized in that made of indium tin oxide (ITO) or carbon nanotubes (CNT). Depositing a transparent electrode material on the lower substrate; Patterning the transparent electrode material to form a plurality of lower transparent electrodes; Depositing a transparent electrode material on the upper substrate; Patterning the transparent electrode material to form a plurality of upper transparent electrodes 84 corresponding to the lower transparent electrodes; Etching a lower surface of the upper substrate in a region where the upper transparent electrode 84 is formed to form a plurality of trenches; The lower transparent electrode is accommodated in the trench so as to correspond to the upper transparent electrode 84 to bond the lower substrate and the upper substrate through an adhesive to form an air gap (gap) by the trench Method for manufacturing a capacitive tactile sensor. The method of claim 8, The transparent electrode material is indium tin oxide (ITO), characterized in that the capacitive tactile sensor manufacturing method. The method of claim 8, The transparent electrode material is a carbon nanotube (CNT) capacitive type tactile sensor manufacturing method characterized in that the. The method of claim 8, Forming a plurality of trenches by etching the lower surface of the upper substrate, wherein the capacitive tactile sensor manufacturing method is performed by wet etching using an aqueous potassium hydroxide (KOH) solution.

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