KR100495901B1 - Capacitance switch - Google Patents

Abstract

In an environment in which strong ESD is applied from the outside, an electrical pulse is applied to only one of the inverting terminal and the non-inverting terminal of the comparator 10, so that an error may occur in the output of the comparator 10. In order to overcome this concern, a compensation capacitor Cc is connected in series between the first sensing variable capacitor Cps and the second sensing variable capacitor Cpr. Then, since the electrical pulse is similarly transmitted to the inverting terminal or the non-inverting terminal due to the presence of the compensation capacitor Cc, the fear of malfunction due to the external electric pulse is greatly reduced. In addition, unlike the conventional case in which a plurality of capacitive switches 30 are arranged in an array form on one dielectric substrate 40, in the case of the present invention, since each capacitive switch 130 is manufactured independently, Even if the substrate is not required and the outer case 120 is curved, the outer connection line 105 may be freely attached to the curved surface as long as it is long enough to serve as a switch.

Description

Capacitive switch

The present invention relates to a capacitive switch, and more particularly, to provide a capacitive switch capable of minimizing malfunction due to electrostatic discharge (hereinafter, referred to as 'ESD') and individually installed one by one.

Unlike conventional push type switches, a capacitive switch that operates only by touching a human body has recently been in the spotlight. The reasons for the spotlight are as follows.

First, it increases the affinity between the user and the product because it is operated only by contact, not by physical force.

Second, although it can be operated by direct contact between human body and metal pad, it can be operated by indirect contact through non-metal by attaching metal pad on the back of non-metallic material such as glass, so that the design of product switch part can be diversified. You can make a more luxurious product.

Third, since switching is not made by contact but only by a change in capacitance, wear and spark do not occur, so the reliability of a product due to a failure does not decrease, and it is possible to use the life of the first switching as it is.

Fourth, the switch itself can be waterproofed so that it can be used without worrying about moisture penetration by attaching it to the product without a separate cover for protecting the switch.

In addition to this, there are various advantages, but since the switching operation is performed by the static electricity accumulated in the human body, there is a high possibility of malfunction in an environment in which strong ESD is applied from the outside. For example, when a finger is placed on a capacitive switch, malfunctions are likely to be caused by ESD by a human body.

In addition, in the conventional case, as shown in FIG. 1A, instead of installing the capacitive switches 30 individually, the plurality of capacitive switches 30 are arranged in an array on one dielectric substrate 40. The arrayed thing is installed as a set. For example, in the case of using an electrostatic switch in an elevator, if the number of floors is 20, the elevator switch unit is provided with 20 two-dimensional capacitance switches 30 arranged on the substrate 40 two-dimensionally. Therefore, when the distance between the capacitive switch 30 is wide, a large substrate 40 is required, which is expensive.

In this case, as shown in FIG. 1B, when the outer case 20 is curved, for example, in the case of a curved surface, since the substrate 40 cannot be bent, electrical connection between the capacitive switch 30 and the outer case 20 can be made. Conductive filler 50 is required.

As described above, the conventional capacitive switch has a high possibility of malfunction in an environment in which strong ESD is applied from the outside. In addition, since the plurality of capacitive switches 30 are arranged in the form of a two-dimensional array on one dielectric substrate 40, when the distance between the capacitive switches 30 is large, a large substrate is required and the price is high. If the outer case 20 is bent, there are many difficulties in its installation.

Accordingly, the technical problem to be achieved by the present invention is to provide a capacitive switch that can be installed individually one by one as well as no malfunction occurs even in an environment where strong ESD is applied from the outside.

The capacitive switch according to the present invention for achieving the above technical problem, by comparing the capacitance value input to the inverting terminal and the non-inverting terminal to each other and outputs a different signal depending on which value is input to which terminal is larger? Capacitance comparator; A first reference capacitor having one terminal connected to the inverting terminal and the other terminal grounded; A second reference capacitor having one terminal connected to the non-inverting terminal and the other terminal being grounded and having a larger capacitance than the first reference capacitor; A first sensing variable capacitor having one terminal connected to a first reference capacitor terminal connected to the inverting terminal and the other terminal floating and having an increased capacitance when an external object approaches the floating terminal; One terminal is connected to a second reference capacitor terminal connected to the non-inverting terminal, and the other terminal is floated and its capacitance increases less than the first sensing variable capacitor when an external object approaches the floating terminal. Two-sensing variable capacitors; And a compensation capacitor connected in series between the first sensing variable capacitor and the second sensing variable capacitor. Characterized in having a.

As an example, the capacitive switch according to the present invention, a dielectric substrate; A first conductive film formed on an upper surface of the substrate; An upper passivation layer covering the upper surface of the substrate while the first conductive layer is interposed therebetween; A second conductive film formed on the bottom surface of the substrate; A capacitance comparator formed on the lower surface of the substrate and comparing different capacitance values input to the inverting terminal and the non-inverting terminal with each other and outputting different signals depending on which terminal has a larger value; A first reference capacitor formed on a lower surface of the substrate and having one terminal electrically connected to the first conductive layer through a via hole of the substrate, the first reference capacitor being electrically connected to the inverting terminal and the other terminal being grounded; A second terminal formed on the bottom surface of the substrate and having one terminal electrically connected to the second conductive layer and at the same time, the second terminal having an electrical capacitance higher than that of the first reference capacitor. Reference capacitor; And a lower passivation layer covering the lower surface of the substrate with the second conductive layer, the first reference capacitor, the second reference capacitor, and the comparator interposed therebetween.

Here, the lower passivation layer is exposed through the upper passivation layer, the first conductive layer, the dielectric substrate, and the lower conduction layer, and a light emitting hole coated with a reflector is further provided on an inner wall thereof, and a light emitting unit is installed in the light emitting hole. desirable.

In addition, it is preferable that a shield case made of a metal material installed to be grounded to cover the lower protective film is further provided, and an elastic electrode covering the upper protective film is further provided.

As another example, a capacitive switch according to the present invention includes a dielectric substrate; A first conductive film formed on an upper surface of the substrate; An upper passivation layer covering the upper surface of the substrate while the first conductive layer is interposed therebetween; A second conductive film formed on the bottom surface of the substrate; A capacitance comparator formed on the lower surface of the substrate and comparing different capacitance values input to the inverting terminal and the non-inverting terminal with each other and outputting different signals depending on which terminal has a larger value; A first reference capacitor formed on a lower surface of the substrate and having one terminal electrically connected to the first conductive layer through a via hole of the substrate, the first reference capacitor being electrically connected to the inverting terminal and the other terminal being grounded; A second terminal formed on the bottom surface of the substrate and having one terminal electrically connected to the second conductive layer and at the same time, the second terminal having an electrical capacitance higher than that of the first reference capacitor. Reference capacitor; And a shield case made of a metal material spaced apart from the substrate by a predetermined distance to cover the bottom surface of the substrate; Characterized in having a. Here, it is preferable that the elastic electrode covering the upper protective film is further provided.

As another example, the capacitive switch according to the present invention, the dielectric substrate; A first conductive film formed on an upper surface of the substrate; An elastic electrode covering the upper surface of the substrate with the first conductive film interposed therebetween; A second conductive film formed on the bottom surface of the substrate; A capacitance comparator formed on the lower surface of the substrate and comparing different capacitance values input to the inverting terminal and the non-inverting terminal with each other and outputting different signals depending on which terminal has a larger value; A first reference capacitor formed on a lower surface of the substrate and having one terminal electrically connected to the first conductive layer through a via hole of the substrate, the first reference capacitor being electrically connected to the inverting terminal and the other terminal being grounded; A second terminal formed on the bottom surface of the substrate and having one terminal electrically connected to the second conductive layer and at the same time, the second terminal having an electrical capacitance higher than that of the first reference capacitor. Reference capacitor; And a lower passivation layer covering the lower surface of the substrate with the second conductive layer, the first reference capacitor, the second reference capacitor, and the comparator interposed therebetween. Here, it is preferable that a shield case made of a metal material installed to be grounded to cover the lower protective film is further provided.

As another example, the capacitive switch according to the present invention, the dielectric substrate; A first conductive film formed on an upper surface of the substrate; A first conductive film guard ring formed on an upper surface of the substrate so as to be spaced apart from the first conductive film by a predetermined distance and surrounding the first conductive film; An upper passivation layer covering the upper surface of the substrate with the first conductive layer and the first conductive layer guard ring interposed therebetween; A second conductive film formed on the bottom surface of the substrate; A second conductive film guard ring formed on a lower surface of the substrate to be spaced apart from the second conductive film by a predetermined distance and surrounding the second conductive film and electrically connected to the first conductive film guard ring through a first via hole of the substrate; A capacitance comparator formed on the lower surface of the substrate and comparing different capacitance values input to the inverting terminal and the non-inverting terminal with each other and outputting different signals depending on which terminal has a larger value; A first reference capacitor formed on a lower surface of the substrate and having one terminal electrically connected to the first conductive film and the inverting terminal through a second via hole of the substrate and the other terminal being grounded; A second reference capacitor formed on a lower surface of the substrate and having one terminal electrically connected to the second conductive film and the non-inverting terminal, the other terminal being grounded and having a larger capacitance than the first reference capacitor; And a lower passivation layer covering the lower surface of the substrate with the second conductive layer, the second conductive layer guard ring, the first reference capacitor, the second reference capacitor, and the comparator interposed therebetween. Also in this case, it is preferable to further provide the above-mentioned light-emitting body.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

Example 1

2A is a circuit diagram illustrating a capacitive switch according to a first embodiment of the present invention.

2A, one terminal of the first reference capacitor Cms is connected to the inverting terminal of the capacitance comparator 10, and the other terminal is grounded. One terminal of the second reference capacitor Cmr is connected to the non-inverting terminal of the capacitance comparator 10 and the other terminal is grounded.

Meanwhile, one terminal of the first sensing variable capacitor Cps is connected to the first reference capacitor Cms terminal connected to the inverting terminal of the capacitance comparator 10, and the other terminal is floating. The capacitance of the first sensing variable capacitor Cps increases as the external object approaches the floating terminal A. FIG. The external object will usually be a finger, but it does not matter as long as it can be a predetermined voltage source in addition to the finger.

One terminal of the second sensing variable capacitor Cpr is connected to the second reference capacitor Cmr terminal connected to the non-inverting terminal of the capacitance comparator 10 and the other terminal is floated. The capacitance of the second sensing variable capacitor Cpr increases as the external object approaches the floating terminal B. FIG.

As the inverting terminal of the capacitance comparator 10, the sum of the first reference capacitor Cms capacitance and the first sensing variable capacitor Cps capacitance is input, and as the non-inverting terminal, the second reference capacitor Cmr capacitance The sum of the capacitance and the capacitance of the second sensing variable capacitor Cpr is input. The capacitance comparator 10 compares capacitance values input to the inverting terminal and the non-inverting terminal with each other and outputs different signals depending on which terminal has a larger value.

Referring to FIG. 2B, for example, when the initial value input to the inverting terminal is set to be larger than the initial value input to the non-inverting terminal, and the finger is touched by the floating electrodes A and B, FIG. That is, when the value of the capacitance input to the non-inverting terminal becomes larger than the inverting terminal when the switch is touched, the comparator 10 first outputs a low signal and then the high value when the switch is touched. ) Signal is output.

On the contrary, when the initial value input to the non-inverting terminal is set to be larger than the initial value input to the inverting terminal and the finger is touched to the floating electrodes A and B, that is, when the switch is touched, the non-inverting is not performed. When the capacitance value input to the inverting terminal becomes larger than that of the terminal, the comparator 10 first outputs a high signal, and then outputs a low signal when the switch is touched.

For example, the second reference capacitor Cmr has a larger capacitance than the first reference capacitor Cms, and as the finger approaches the floating terminals A and B, the first sensing variable capacitor Cps is blackouted. When the capacitance increase amount is larger than the second sensing variable capacitor Cpr, the capacitance initially inputted to the non-inverting terminal is larger than that inputted to the inverting terminal, and then the finger is placed on the floating terminals A and B. At some point when approaching, the capacitance inputted to the inverting terminal becomes larger than the capacitance inputted to the non-inverting terminal, so that the comparator 10 outputs a low signal from a high signal. Such a switching operation is preferably performed when the finger touches the floating terminals A and B. FIG.

On the other hand, in an environment where strong ESD is applied from the outside, an electric pulse is applied to only one of the inverting terminal and the non-inverting terminal, so that an error may occur in the output of the capacitive comparator 10. In order to overcome this concern, a compensation capacitor Cc is connected in series between the first sensing variable capacitor Cps and the second sensing variable capacitor Cpr. Then, since the electrical pulse is similarly transmitted to the inverting terminal or the non-inverting terminal due to the presence of the compensation capacitor Cc, the fear of malfunction due to the external electric pulse is greatly reduced.

As the compensation capacitor Cc, a dielectric substrate or a guide ring described later may be used, but a capacitor such as MLCC may be used directly.

The smaller the difference in capacitance between the first reference capacitor Cms and the second reference capacitor Cmr becomes, the smaller the capacitance of the capacitance input to the two terminals of the capacitance comparator 10 can be easily reversed even if an external object approaches. Occurs, resulting in higher switch sensitivity.

3A to 3C are diagrams for describing the capacitive switch 130 according to the present invention implemented according to the circuit diagram of FIG. 2A. FIG. 3A is a cross-sectional view, FIG. 3B is a top view, and FIG. 3C is a bottom view.

3A to 3C, a first conductive film 120a is attached to an upper surface of the dielectric substrate 140, and a second conductive film 125a is attached to a lower surface of the dielectric substrate 140. The upper passivation layer 180 covers the upper surface of the substrate 140 with the first conductive layer 120a interposed therebetween.

The sensor circuit unit 100 is disposed on the bottom surface of the substrate 140 adjacent to the second conductive film 125a. The sensor circuit unit 100 is provided with a comparator 10 of FIG. 2A, a first reference capacitor Cms, and a second reference capacitor Cmr. As the first reference capacitor Cms and the second reference capacitor Cmr, a multi-layer ceramic capacitor (MLCC) type chip capacitor may be used.

Of course, the comparator 10, the first reference capacitor Cms, and the second reference capacitor Cmr are not necessarily implemented as one circuit part, but they are made of one circuit part in advance, and one on the bottom surface of the substrate 140. It is recommended to install as a set of.

A via hole is formed in the substrate 140, and a buried conductive layer 142 ′ is filled in the via hole. One terminal of the first reference capacitor Cms is electrically connected to the first conductive film 120a through the buried conductive layer 142 'and is also electrically connected to the inverting terminal of the comparator 10. The other terminal of the first reference capacitor Cms is Grounded.

One terminal of the second reference capacitor Cmr is electrically connected to the second conductive film 125a and also electrically connected to the non-inverting terminal of the comparator 10, and the other terminal is grounded.

The lower passivation layer 170 covers the lower surface of the substrate 140 with the second conductive layer 125a and the sensor circuit unit 100 interposed therebetween. In order to provide a moisture proof function, the upper passivation layer 180 may be formed by applying a moisture proof paint, and the lower passivation layer 170 may be formed by molding with a mold compound. The lower passivation layer 170 also serves to protect the sensor circuit unit 100.

In addition, the lower protective layer 170 is formed in the lower surface of the substrate 140 so that the lower protective layer 170 and the substrate 140 are tightly coupled so that the lower protective layer 170 is fitted into the groove H to be in close contact with each other. The tighter the coupling between the lower passivation layer 170 and the substrate 140, the better the moisture-proof effect.

When an external object, for example, a finger, approaches the upper surface of the substrate 140, a first sensing variable capacitor Cps is formed between the external object and the first conductive film 120a, and between the external object and the second conductive film 125a. The second sensing variable capacitor (Cpr) is generated.

As the external object approaches, the capacitances of the first sensing variable capacitor Cps and the second sensing variable capacitor Cpr increase together. At this time, since the second conductive film 125a is farther from the external object than the first conductive film 120a and the dielectric substrate 140 is present, the first sensing variable capacitor Cps is the second sensing. It has a larger capacitance than the variable capacitor Cpr, and the difference becomes larger as the external object approaches.

As the difference in capacitance between the first sensing variable capacitor Cps and the second sensing variable capacitor Cpr increases, the response of the second conductive film 125a is greater than that of the first conductive film 120a. It is better to make the area smaller.

When the first conductive film 120a and the second conductive film 125a are made of different materials, the first sensing variable capacitor Cps and the second sensing variable capacitor Cpr cause different changes over time, which is undesirable. The first conductive film 120a and the second conductive film 125a may be made of the same material.

Since the dielectric substrate 140 serves as the compensation capacitor Cc, if the thickness, area, and material of the substrate 140 are appropriately determined, a desired compensation capacitor Cc capacitance can be obtained.

Supplying power to the output line 105a connected to the output terminal of the comparator 10, the ground line 105c commonly connected to the ground terminal of the first reference capacitor and the second reference capacitor, and the sensor circuit unit 100. The operating voltage line 105b is installed to penetrate the lower passivation layer 170.

Unlike the conventional case in which several capacitive switches 30 are arranged in an array form on one dielectric substrate 40 (FIGS. 1A and 1B), each of the capacitive switches 130 is independent of each other. Since it is manufactured as a large substrate is not required, even if the outer case 120 is bent as shown in FIG. 4, the external connection line 105 can be freely attached to the curved surface to perform a role as a switch.

As described above, the capacitive capacitor according to the first embodiment of the present invention does not cause malfunction even in an environment in which strong ESD is applied from the outside, and can be installed individually one by one, thus eliminating the need for a large substrate and the outer case 120. Installation is easy even when the cable is bent.

Of course, it is natural that a plurality of capacitive switches may be arranged in an array form on one dielectric substrate and installed as a set according to necessity, without being separately attached to each module and attaching them separately.

Example 2

5A to 5C are diagrams for describing the capacitive switch 130 according to the second embodiment of the present invention. FIG. 5A is a cross-sectional view, FIG. 5B is a plan view, and FIG. 5C is a bottom view.

As shown in the drawing, a three-terminal multi-connector 107 is further provided at the ends of the output line 105a, the operating voltage line 105b, and the ground line 105c shown in the first embodiment for the convenience of connection with an external circuit. It may be.

Example 3

6A to 6C are diagrams for describing the capacitive switch 130 according to the third embodiment of the present invention. FIG. 6A is a cross-sectional view, FIG. 6B is a plan view, and FIG. 6C is a bottom view.

 As shown, the output terminal of the comparator 10, the ground terminal of the first reference capacitor (Cms) and the second reference capacitor (Cmr), and is connected to the operating voltage terminal for supplying power to the sensor circuit unit (100) The three-terminal multi-connector 108 may be installed to be directly connected to the sensor circuit unit 100 to penetrate the lower passivation layer 170.

Example 4

7A to 7C are diagrams for describing the capacitive switch 130 according to the fourth embodiment of the present invention. FIG. 7A is a cross-sectional view, FIG. 7B is a plan view, and FIG. 7C is a bottom view.

7A to 7C, a shield case 300 made of metal covering the lower passivation layer 170 is further installed. The shield case 300 is made of metal in a simple clip form to be inserted under the capacitive switch, and installed to be electrically coupled with a ground wire that is pre-installed using the elasticity of the metal. Of course, it may be melted with lead and connected to the ground wire.

Since the influence of the capacitance change or the electromagnetic field induced on the lower surface of the capacitive switch is blocked by the shield case 300, the malfunction of the switch is further prevented. In addition, since the shield case 300 is installed only on the lower surface of the capacitive switch, only the capacitance change in the upper side of the switch mainly contributing to the switching operation is mainly sensed, thereby enabling the switch to operate perfectly.

The lower protective film 170 formed by molding with a molding compound may be absent to protect the moisture proof and the sensor circuit unit 100. That is, the shield case 300 may be provided so as to have a proper separation distance from the substrate 140 without applying the molding compound.

An elastic electrode 400 covering the upper protective layer 180 is installed. When the capacitive switch 130 is attached to the curved outer case 120 as shown in FIG. 4, the capacitive switch 130 is closely attached to the outer case 120 by the elasticity of the elastic electrode 400.

If the capacitive switch 130 is not in close contact with the outer case 120, the air layer existing in the space between the outer case 120 and the capacitive switch 130 serves as one dielectric layer. Since this space is not constant and will vary for each installation position of the capacitive switch 130, there is a high risk of switching errors. Therefore, there is a need to install the elastic electrode 400.

 The elastic electrode 400 is particularly useful in the case of FIG. 1B in which a plurality of capacitive switches are arranged in an array form on one substrate in a curved outer case.

In addition to the output line 105a, the operating voltage line 105b, and the ground line 105c, a support line 105d, which serves as a support stand, is installed to penetrate the lower passivation layer 170 and the shield case 300 so that the switch 130 It is located around the edge.

Example 5

8A to 8C are diagrams for describing the capacitive switch 130 according to the fifth embodiment of the present invention, and show a case in which the upper passivation layer 180 and the shield case 300 are not present in the fourth embodiment. Even in this case, the present invention is implemented.

Example 6

9A to 9C are diagrams for describing the capacitive switch 130 according to the sixth embodiment of the present invention, and show a case in which only the upper passivation layer 180 is absent in the fifth embodiment. Even in this case, the present invention is implemented.

Without the upper passivation layer 180, the dielectric thickness existing between the finger and the first conductive layer 120a and between the finger and the second conductive layer 125a is reduced. Therefore, the capacitance change generated when the finger approaches the outer case 120 is large, thereby reducing the switching error.

Example 7

10A to 10C are diagrams for describing the capacitive switch 130 according to the seventh embodiment of the present invention. As described in the fourth embodiment, FIGS. 10A to 10C do not install the lower passivation layer 170 and are properly spaced apart from the substrate 140. This is the case where the shield case 300 is installed to have a distance.

Example 8

11A to 11C are diagrams for describing the capacitive switch 130 according to the eighth embodiment of the present invention, except that the three-terminal multi-connector 108 as described in the third embodiment is installed. Same as 4

Example 9

12A to 12C are diagrams for describing the capacitive switch 130 according to the ninth embodiment of the present invention, except that the three-terminal multi-connector 108 as described in the third embodiment is installed. Same as 6.

Example 10

FIG. 13 is a circuit diagram illustrating a capacitive switch according to a ninth embodiment of the present invention, and FIGS. 14A to 14C illustrate the capacitive switch 130 according to the present invention which is actually implemented according to the circuit diagram of FIG. 13. Figures for. Here, FIG. 14A is a sectional view, FIG. 14B is a top view, and FIG. 14C is a bottom view.

14A through 14C, light emitting holes through the upper passivation layer 180, the first conductive layer 120a, the dielectric substrate 140, and the lower conductive layer 125a to expose the lower passivation layer 170 are provided. The light emitting unit 200 is further provided in the light emitting hole. A light emitting diode (LED) may be used as the light emitter 200. The inner wall of the light emitting hole is coated with a reflector 210 to increase the reflectivity of the light emitter 200.

When the switching output is made in the comparator 10, when the light emitter 200 is connected to an external control circuit (not shown) such as a microcomputer so that the light emitter 200 emits light, the capacitive switch 130 is external as shown in FIG. 4. Even when the case 120 is covered, a person can visually determine the switch operation.

When the light emitter 200 is provided as described above, instead of the three-terminal multi-connector 107 or 108, a four-terminal multi-connector 108 ′ having an additional power line for supplying power to the light-emitting body 200 is used. It is desirable to.

The bottom of the light emitting unit 200 may be larger than the diameter of the light emitting hole so that the side surface of the light emitting unit 200 has a step shape, and the light emitting unit 200 may be installed to be fitted from the lower portion of the substrate 140 to the upper portion.

Example 11

15A to 15C are diagrams for describing the capacitive switch 130 according to the eleventh embodiment of the present invention. 15A is a sectional view, FIG. 15B is a plan view, and FIG. 15C is a bottom view.

15A to 15C, a first conductive film 120a is formed on an upper surface of the dielectric substrate 140, and a first spaced apart from the first conductive film 120a by a predetermined distance around the first conductive film 120a. The guard ring conductive film 120b is formed. An upper protective film covering the upper surface of the substrate 140 while the first conductive film 120a and the first conductive film guard ring 120b are interposed therebetween is not shown.

A second conductive film 125a is formed on the bottom surface of the substrate 140, and a second conductive film guard ring 125b spaced apart from the second conductive film 125a by a predetermined distance is formed around the second conductive film 125a. . The second conductive film guard ring 125b is electrically connected to the first conductive film guard ring 120b through the first investment conductive layer 141 filled in the first via hole formed in the substrate 140.

The sensor circuit unit 100 is installed outside the second conductive film guard ring 125b. The sensor comparator 100 includes the capacitance comparator 10, the first reference capacitor Cms, and the second reference capacitor Cmr of FIG. 2.

One terminal of the first reference capacitor Cms is electrically connected to the inverting terminal of the comparator 10 and the first conductive film 120a through the second investment conductive layer 142 filled in the second via hole. Grounded. One terminal of the second reference capacitor Cmr is electrically connected to the non-inverting terminal of the comparator 10 and the second conductive film 125a, and the other terminal of the second reference capacitor Cmr is grounded.

The lower protective film covering the lower surface of the substrate 140 while the second conductive film 125a, the second conductive film guard ring 125b, and the sensor circuit unit 100 are interposed therebetween is not shown. As described in the first embodiment, the first conductive film 120a, the first conductive film guard ring 120b, the second conductive film 125a, and the second conductive film guard ring 125b are made of the same material. good.

In the present exemplary embodiment, the compensation capacitor Cc is not only between the dielectric substrate 140 but also between the first conductive film 120a and the first conductive film guard ring 120b, and the second conductive film 120b and the second conductive film guard. It is also formed between the rings 125b.

Therefore, the capacitance in the vertical direction of the compensation capacitor Cc will be affected by the substrate material, the thickness of the substrate, and the area of the two electrodes on the upper and lower surfaces, and the capacitance in the horizontal direction is determined by the first conductive film 120a. ) And the gap between the first conductive film guard ring 120b and between the second conductive film 125a and the second conductive film guard ring 125b and the peripheral circumference thereof.

On the other hand, it is preferable to further include the above-described light emitter 200 in the case of the present embodiment.

As described above, according to the present invention, malfunction does not occur even in an environment in which strong ESD is applied from the outside due to the presence of the compensation capacitor Cc. In addition, since the capacitive switches 130 may be individually installed one by one, the outer case 120 may be attached to the curved surface even when the outer case 120 is curved.

In addition, since the plurality of capacitive switches 130 are not formed on a single substrate and installed as a set, a separate substrate is not required even if the distance between the capacitive switches 130 is wide.

Although various embodiments have been presented in describing the present invention, they should not be implemented independently, and various embodiments may be implemented in combination with each other. That is, the present invention is not limited only to the above embodiments, and it is apparent that many modifications are possible by those skilled in the art within the technical spirit of the present invention.

1A and 1B are diagrams for explaining a conventional capacitive switch;

2A and 2B are circuit diagrams for explaining a capacitive switch according to the present invention;

3A to 3C are views for explaining a capacitive switch according to a first embodiment of the present invention;

4 is a view for explaining the shape in which the capacitive switch is installed in the outer case according to the present invention;

5A to 5C are views for explaining a capacitive switch according to a second embodiment of the present invention;

6A to 6C are diagrams for describing a capacitive switch according to a third embodiment of the present invention;

7A to 7C are diagrams for describing a capacitive switch according to a fourth embodiment of the present invention;

8A to 8C are diagrams for describing a capacitive switch according to a fifth embodiment of the present invention;

9A to 9C are diagrams for describing a capacitive switch according to a sixth embodiment of the present invention;

10A to 10C are diagrams for describing a capacitive switch according to a seventh embodiment of the present invention;

11A to 11C are views for explaining a capacitive switch according to an eighth embodiment of the present invention;

12A to 12C are views for explaining a capacitive switch according to a ninth embodiment of the present invention;

13 is a circuit diagram for explaining a capacitive switch according to an embodiment of the present invention;

14A to 14C are views for explaining a capacitive switch according to a tenth embodiment of the present invention;

15A to 15C are views for explaining a capacitive switch according to an eleventh embodiment of the present invention;

<Description of reference numerals and reference numerals for the main parts of the drawings>

10: capacitive comparator 20, 120: outer case

30, 130: capacitive switch 40, 140: dielectric substrate

50: conductive filler 100: sensor circuit portion

105a: output line 105b: operating voltage line

105c: Ground wire 107, 108: 3-terminal multi-connector

108 ': 4-terminal multi-connector 120a: first conductive film

120b: first guard ring conductive film 125a: second conductive film

125b: second conductive film guard ring 141: first buried conductive layer

142: second buried conductive layer 142 ': buried conductive layer

170: lower protective film 180: upper protective film

200: light emitter 210: reflector

Cms: First Reference Capacitor Cmr: Second Reference Capacitor

Cps: first sensing variable capacitor Cpr: second sensing variable capacitor

300: shield case 400: elastic electrode

Claims (26)

A capacitance comparator for comparing the capacitance values input to the inverting terminal and the non-inverting terminal with each other and outputting different signals depending on which terminal has a larger value; A first reference capacitor having one terminal connected to the inverting terminal and the other terminal grounded; A second reference capacitor having one terminal connected to the non-inverting terminal and the other terminal being grounded and having a larger capacitance than the first reference capacitor; A first sensing variable capacitor having one terminal connected to a first reference capacitor terminal connected to the inverting terminal and the other terminal floating and having an increased capacitance when an external object approaches the floating terminal; One terminal is connected to a second reference capacitor terminal connected to the non-inverting terminal, and the other terminal is floated and its capacitance increases less than the first sensing variable capacitor when an external object approaches the floating terminal. Two-sensing variable capacitors; And A compensation capacitor connected in series between the first sensing variable capacitor and the second sensing variable capacitor; Capacitive switch comprising a. Dielectric substrates; A first conductive film formed on an upper surface of the substrate; An upper passivation layer covering the upper surface of the substrate while the first conductive layer is interposed therebetween; A second conductive film formed on the bottom surface of the substrate; A capacitance comparator formed on the lower surface of the substrate and comparing different capacitance values input to the inverting terminal and the non-inverting terminal with each other and outputting different signals depending on which terminal has a larger value; A first reference capacitor formed on a lower surface of the substrate and having one terminal electrically connected to the first conductive layer through a via hole of the substrate, the first reference capacitor being electrically connected to the inverting terminal and the other terminal being grounded; A second terminal formed on the bottom surface of the substrate and having one terminal electrically connected to the second conductive layer and at the same time, the second terminal having an electrical capacitance higher than that of the first reference capacitor. Reference capacitor; And And a lower passivation layer covering the lower surface of the substrate with the second conductive layer, the first reference capacitor, the second reference capacitor, and the comparator interposed therebetween. The capacitive switch of claim 2, wherein an area of the second conductive film is smaller than that of the first conductive film. The capacitive switch of claim 2, wherein the first conductive film and the second conductive film are made of the same material. The capacitive switch of claim 2, wherein the first reference capacitor and the second reference capacitor are MLCCs. The capacitive switch of claim 2, wherein the comparator, the first reference capacitor, and the second reference capacitor are implemented as one circuit unit. 7. The power supply circuit of claim 6, wherein an output line connected to an output terminal of the comparator, a ground line commonly connected to the ground terminals of the first reference capacitor and the second reference capacitor, and an operating voltage line for supplying power to the circuit unit. Capacitance switch characterized in that it is installed to penetrate the lower protective film. The method of claim 7, wherein the support line through the lower protective film is further provided together with the output line, the ground line, and the operating voltage line, wherein the output line, the ground line, the operating voltage line, and the support line are positioned along the edge of the lower protective film. Capacitive switch, characterized in that installed. 8. The capacitive switch of claim 7, further comprising a three-terminal multi-connector connected to the output line, the ground line, and the operating voltage line. The circuit part of claim 6, wherein a three-terminal multi-connector connected to an output terminal of the comparator, a ground terminal of the first reference capacitor and the second reference capacitor, and an operating voltage terminal for supplying power to the circuit part. Capacitive switch, characterized in that is directly connected to and fixed through the lower protective film. The capacitive switch of claim 2, wherein the upper protective film is formed by applying a moisture proof paint. The capacitive switch of claim 2, wherein the lower protective layer is formed by molding with a mold compound. The capacitive switch according to claim 2, wherein a groove is formed in the lower surface of the substrate, and the lower protective film is installed to fit in the groove. The light emitting hole of claim 2, wherein the lower protective layer is exposed through the upper protective layer, the first conductive layer, the dielectric substrate, and the lower conductive layer, and a light emitting hole coated with a reflector is further provided on an inner wall thereof. Capacitive switch characterized in that the installation. 15. The capacitive switch of claim 14, wherein said light emitter is an LED. 15. The capacitive switch of claim 14, wherein the light emitting body has a stepped shape such that a bottom thereof is larger than a diameter of the light emitting hole, and is fitted by being fitted from a lower portion of the substrate to an upper portion thereof. The capacitive switch of claim 2, further comprising a shield case made of a metal that is grounded to cover the lower passivation layer. The capacitive switch of claim 2, further comprising an elastic electrode covering the upper passivation layer. Dielectric substrates; A first conductive film formed on an upper surface of the substrate; An upper passivation layer covering the upper surface of the substrate while the first conductive layer is interposed therebetween; A second conductive film formed on the bottom surface of the substrate; A capacitance comparator formed on the lower surface of the substrate and comparing different capacitance values input to the inverting terminal and the non-inverting terminal with each other and outputting different signals depending on which terminal has a larger value; A first reference capacitor formed on a lower surface of the substrate and having one terminal electrically connected to the first conductive layer through a via hole of the substrate, the first reference capacitor being electrically connected to the inverting terminal and the other terminal being grounded; A second terminal formed on the bottom surface of the substrate and having one terminal electrically connected to the second conductive layer and at the same time, the second terminal having an electrical capacitance higher than that of the first reference capacitor. Reference capacitor; And A shield case made of a metal material which is grounded to be spaced apart from the substrate by a predetermined distance to cover the bottom surface of the substrate; Capacitive switch comprising a. 20. The capacitive switch of claim 19, further comprising an elastic electrode covering the upper passivation layer. Dielectric substrates; A first conductive film formed on an upper surface of the substrate; An elastic electrode covering the upper surface of the substrate with the first conductive film interposed therebetween; A second conductive film formed on the bottom surface of the substrate; A capacitance comparator formed on the lower surface of the substrate and comparing different capacitance values input to the inverting terminal and the non-inverting terminal with each other and outputting different signals depending on which terminal has a larger value; A first reference capacitor formed on a lower surface of the substrate and having one terminal electrically connected to the first conductive layer through a via hole of the substrate, the first reference capacitor being electrically connected to the inverting terminal and the other terminal being grounded; A second terminal formed on the bottom surface of the substrate and having one terminal electrically connected to the second conductive layer and at the same time, the second terminal having an electrical capacitance higher than that of the first reference capacitor. Reference capacitor; And And a lower passivation layer covering the lower surface of the substrate with the second conductive layer, the first reference capacitor, the second reference capacitor, and the comparator interposed therebetween. 22. The capacitive switch of claim 21, further comprising a metal shield case which is grounded to cover the lower protective film. Dielectric substrates; A first conductive film formed on an upper surface of the substrate; A first conductive film guard ring formed on an upper surface of the substrate so as to be spaced apart from the first conductive film by a predetermined distance and surrounding the first conductive film; An upper passivation layer covering the upper surface of the substrate with the first conductive layer and the first conductive layer guard ring interposed therebetween; A second conductive film formed on the bottom surface of the substrate; A second conductive film guard ring formed on a lower surface of the substrate to be spaced apart from the second conductive film by a predetermined distance and surrounding the second conductive film and electrically connected to the first conductive film guard ring through a first via hole of the substrate; A capacitance comparator formed on the lower surface of the substrate and comparing different capacitance values input to the inverting terminal and the non-inverting terminal with each other and outputting different signals depending on which terminal has a larger value; A first reference capacitor formed on a lower surface of the substrate and having one terminal electrically connected to the first conductive film and the inverting terminal through a second via hole of the substrate and the other terminal being grounded; A second reference capacitor formed on a lower surface of the substrate and having one terminal electrically connected to the second conductive film and the non-inverting terminal, the other terminal being grounded and having a larger capacitance than the first reference capacitor; And And a lower protective layer covering the lower surface of the substrate while the second conductive film, the second conductive film guard ring, the first reference capacitor, the second reference capacitor, and the comparator are interposed therebetween. 24. The capacitive switch of claim 23, wherein the comparator, the first reference capacitor, and the second reference capacitor are implemented as one circuit unit. 25. The capacitive switch of claim 24, wherein said circuit portion is provided outside said second conductive film guard ring. 24. The capacitive switch of claim 23, wherein the first conductive film guard ring, the first conductive film guard ring, the second conductive film guard ring, and the second conductive film guard ring are made of the same material.