KR101327399B1 - Sensor and method for sensor manufacture - Google Patents

Abstract

The present invention relates to a capacitive sensor and a manufacturing method thereof and, more specifically, to a sensor having a capacitive direction key capable of recognizing pressure and a manufacturing method thereof. The capacitive sensor of the present invention comprises a bottom electrode part which has an electrode; a top electrode part has an electrode corresponding to the electrode formed on the bottom electrode part; a cavity forming part which is formed between the bottom electrode part and the top electrode part and has a hole corresponding to the electrode formed on the bottom electrode part; and an actuator which is formed on the upper part of the top electrode part and has a protrusion part corresponding to the electrode formed on the top electrode part.

Description

Capacitive sensor and its manufacturing method {Sensor and Method for Sensor manufacture}

The present invention relates to a capacitive sensor and a method of manufacturing the same, and more particularly, to a sensor having a capacitive direction key capable of pressure recognition and a method of manufacturing the same.

In general, in the case of the mouse of the personal PC most commonly used, the direction and click portion is made of a separate sensor operation.

Figure 1 shows a conventional PC mouse and optical mouse. The mouse consists of a case, a button to indicate the action, and a round trackball. The mouse contains a round ball that works by rolling the ball off the floor, and there are two discs in the groove, each with two light emitting diodes and two photodiodes. As the mouse moves, it transmits a change in the mouse's position to the computer, which causes the computer to move the cursor on the screen in the same direction as the mouse. Move the cursor to the desired location and click the mouse button to execute the command indicated by the icon. Such movement and clicking of the cursor are performed by the operation of different sensors, and in the case of clicking buttons, only the simple ON / OFF operation is performed.

The optical mouse uses optical technology to move the cursor. The optical mouse has an optical sensor (metal oxide CMOS semiconductor) that acts as a very small camera, and a small LED that emits red light. The red light emitted by the engineering mouse is reflected onto the optical sensor, and the signal of the sensor is again reflected in each image. The signal can be sent to a digital signal processing device (DSP), and the DSP can detect the patterns of each image and see how those patterns have moved compared to the previous image. Based on the change in the sequence of images, the DSP determines how far the mouse has moved, sends the corresponding coordinates to the computer, and the computer moves the cursor on the screen based on the coordinates received from the mouse. However, such a mouse also requires a click using a separate sensor to click, such as the movement and click of the cursor is not made in the same sensor, and also consists of a sensor that can not react to the force, so the various human emotions in the future Difficult to respond

The same is true of mobile phones used in our real life, game consoles and portable game consoles used at home. In general, a game machine is composed of a joystick or a direction key for directional movement. Home game consoles use joysticks or remote controls that can be moved. In the case of the joystick, the joystick is moved up, down, left and right to move the direction, and a separate click key is pressed to click. In the case of the remote control, a movement command of an object is performed by directly pressing a direction movement key for direction movement. Mobile phones and handheld game consoles have a similar behavior to remote controllers.

Figure 2 shows a typical mobile phone or portable game machine. As illustrated in FIG. 2, a navigation key for up, down, left, and right direction movements is located in the case of a mobile phone or a game machine, and in the case of a game machine, two sets are provided to be held in both hands. These keys have an on / off structure for simple movement, and dome switch-type sensors are widely used in key pads of mobile phones. The structure of such a sensor is a form that can not respond to the pressing force of the human, there is no limit to be applied to various mobile phone UI (user interface) and emotional games in the future. Depending on the user used, the user may need a sensor that can add various functions depending on whether the user presses with a large force or a small force.

SUMMARY OF THE INVENTION An object of the present invention is to propose a capacitive sensor and a method of manufacturing the same, which output different output values according to the magnitude of pressure applied to an upper end of the sensor.

Another object of the present invention is to propose a method of simplifying an assembly process of a capacitive sensor assembled into a plurality of structures.

To this end, the capacitive sensor of the present invention includes a lower electrode portion forming an electrode, an upper electrode portion forming an electrode at a position corresponding to an electrode formed on the lower electrode portion, the lower electrode portion and the upper electrode portion. A cavity forming part formed between the cavity and a hole formed at a position corresponding to the electrode formed at the lower electrode part, and formed at an upper end of the upper electrode part, and at a position corresponding to the electrode formed at the upper electrode part of the lower surface. It includes an actuator forming a.

To this end, the sensor manufacturing method of the present invention comprises the steps of forming an electrode on the lower electrode portion, the cavity forming portion forming a perforation in a position corresponding to the electrode formed on the lower electrode portion laminated on the upper electrode portion, Stacking an upper electrode part forming an electrode at a position corresponding to an electrode formed at a lower electrode part on an upper end of the cavity forming part, and an actuator having a protrusion formed at a position corresponding to an electrode formed on the upper electrode part among lower surfaces; And forming a protrusion on an upper end of the upper electrode part, and forming a protrusion at an upper end of the cavity forming part, and forming a hole at a position corresponding to the protrusion at a lower end of the upper electrode part.

The capacitive sensor consisting of a lower electrode portion, a cavity forming portion, an upper electrode portion, and an actuator according to the present invention forms fixing protrusions and holes in structures that are coupled to each other in order to streamline the assembly process. Thus, by forming the fixing protrusions and holes in the structure to be coupled to each other it is possible to simplify the assembly process.

In addition, the interval between the lower electrode portion and the upper electrode portion is linearly changed according to the pressure applied from the upper side, so that at least three or more control information can be output using one sensor.

Figure 1 shows the shape of a conventional general mouse,
2 illustrates a direction key of a conventional mobile phone and a portable game,
3 illustrates a structure of a capacitive sensor according to an embodiment of the present invention.
4 illustrates an example of calculating a capacitance between an upper electrode portion and a lower electrode portion according to an embodiment of the present invention.
5 shows a coupling method of a sensor and an actuator according to an embodiment of the present invention,
6 is a view illustrating a method of coupling each structure constituting a sensor according to an embodiment of the present invention.
7 shows a design diagram of a capacitive sensor according to an embodiment of the present invention,
8 illustrates an output value according to a load applied to a sensor according to an embodiment of the present invention.
9 illustrates a sensor part and an actuator including a lower electrode part, a cavity forming part, and an upper electrode part according to an embodiment of the present invention.
10 shows an example of packaging of a sensor according to an embodiment of the present invention.

The foregoing and further aspects of the present invention will become more apparent through the preferred embodiments described 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 this embodiment of the present invention.

3 shows a structure of a capacitive sensor according to an embodiment of the present invention. Hereinafter, the capacitive sensor structure according to an embodiment of the present invention will be described in detail with reference to FIG. 3.

The sensor is largely composed of four structures combined. First, the lower electrode part 300 forming the lower electrode, a cavity structure 310 for securing a space for driving the sensor by an external load, and an upper electrode part for forming capacitance with the lower electrode ( 320 and an actuator 330 for efficiently driving the sensor.

4 shows a formula for calculating the capacitance value of the sensor. The capacitance of the sensor is calculated using the dielectric constant value of the material comprised between the upper electrode and the lower electrode, the area of the upper electrode and the lower electrode, and the distance between the lower electrode and the upper electrode.

Hereinafter, the structure of the above-described sensor will be described in detail.

Lower electrode unit 300

The lower electrode portion of the capacitive sensor constitutes an electrode in the sensor to be positioned in the upper, lower, left, right, and center portions on the hard material as shown in FIG. 3. The five sensors of the up, down, left, right, and center are composed of four direction keys and a selection key in the center when operating as a navigation sensor, and form capacitance with the upper electrode. As a hard material to be used herein, various materials such as FR4, plastic, polymer, silicone, etc., which are commonly used, may be used, and flexible materials may be used as necessary. The shape of the electrode may be in any shape other than round or square. The signal line for signal processing protrudes a certain length to connect with the connector part. As the material of the electrode portion used herein, all conductive materials may be used, and in general, various materials such as copper, gold, aluminum, tin, and silver may be used.

Space forming part (cavity forming part) 310

In order to operate the capacitive sensor, the signal is changed by changing the gap between the upper electrode and the lower electrode. In order to change the signal, it is necessary to secure an appropriate space between the upper electrode and the lower part, and for this, a structure for forming a cavity is required as shown in FIG. 3. The cavity forming part is manufactured in the form of a perforated shape in the same shape as that of the upper electrode. In addition, the cavity forming portion may be a material such as FR4, plastic, polymer, silicon, and the like. Since the cavity forming part plays an important role in the sensitivity of the entire sensor, the thickness of the material used for forming the cavity is appropriately adjusted according to the intended use. However, the cavity forming portion is placed on the upper end of the lower electrode portion, and is manufactured to be somewhat smaller than the lower electrode portion to prevent interference with the connector connection portion of the lower electrode portion.

In addition, the cavity part is generally used as an air layer, but a material having a high dielectric constant such as polymer, silicone, rubber, gel, glycerin, etc. is used in the air layer composed of air to give a user a feeling when clicking on the sensor or to increase the magnitude of the output signal. You can also fill it in.

Upper electrode portion (role of spring) 320

The upper electrode portion is a portion necessary for forming capacitance with the lower electrode portion. In order to substantially form the capacitance, the upper electrode and the lower electrode are required, and the operation characteristic of the sensor detects a change in the gap between the two electrodes due to the displacement of the upper electrode portion, and represents an output signal due to an external load. Accordingly, the lower electrode is a fixed type electrode, and the upper electrode is an electrode portion that is deformed by an external load. One of the most important things about the sensor's behavior is its reproducibility, reliability, and resilience. It is also necessary that displacement of the upper electrode portion is caused well by the external load, but it is necessary to restore the original shape in a short time as soon as the applied load is removed. That is, the upper electrode is a part that acts like a spring. In the present invention, the upper electrode is intended to use a material excellent in elasticity, restoring force in order to improve such characteristics.

The material used for the upper electrode is a conductive material, and a material having excellent elasticity and resilience should be used. In the present invention, a material such as SUS may be used. Of course, a variety of metal materials such as aluminum may be used even if the material is not SUS. In the case of using an insulator material having excellent elasticity and resilience in addition to the metal material, a metal material may be applied to the surface of the electrode part. Such electrode formation may be performed using metal deposition, photolithography, or the like, or may be used by attaching to an insulator having excellent elasticity and resilience by forming an electrode portion on a thin film material such as a polymer. In detail, the upper electrode part may use any material having excellent elasticity and resilience of the non-conductive material in addition to the conductive material.

Actuator 330

The actuator is composed of the lower electrode portion, the cavity forming portion, and the upper electrode portion as described above, and is a portion necessary for effectively transferring an external load to the sensor portion. In general, when there is no actuator, it is difficult to apply the load to the sensor of the upper, lower, left, right, and center part by the external load exactly where desired. In order to effectively transmit such a force to each sensor as shown in FIG. Actuator required. Actuators are manufactured so that a force can be applied to the center of each sensor, and the materials of the actuators can be made by pouring various materials such as polymer, rubber, gel, silicone, etc. into a mold shape and curing them or by injection molding. Can be. Since the upper end of the actuator is a place where a human finger is actually placed, it may be manufactured in a flat form or in a somewhat rounded form as shown in FIG. . In addition, since the actuator should be fixed on the upper electrode, the actuator may be fixed to the edge of the actuator with a poron tape or a thin adhesive. In addition, since the actuator is also important to be aligned with the central portion of the sensor, as shown in Figure 5b to form a hole in the upper electrode portion so that the specific portion of the actuator can be inserted into the upper electrode portion is formed in such a way that a part of the actuator is inserted thereon It is possible.

In fabricating the sensor, the exact alignment of each element is important. In order to solve this problem, we propose a method for facilitating alignment in manufacturing each structure shown in FIG.

The lower electrode portion is the lowermost portion, and the cavity forming portion placed on the upper portion of the lower electrode portion has the same outer size as the lower electrode portion, and thus is simply coupled with the lower electrode portion. However, the upper electrode part serving as a spring seated on the upper part of the cavity forming part forms an upper electrode fixing part (or protrusion) on the upper part of the cavity forming part to easily combine with the cavity forming part. . Thereafter, when forming the upper electrode part and forming a hole that is slightly larger than the upper electrode fixing part formed in the cavity forming part, the assembly can be accurately assembled without any alignment method. The material used for assembly can be firmly bonded to all the structures using a thin film tape or a liquid adhesive.

FIG. 7 illustrates a CAD design schematically showing a lower electrode portion, a cavity forming portion, and an upper electrode portion according to an embodiment of the present invention, and a shape in which they are coupled.

8 illustrates a change in an output signal with respect to a load applied to a sensor according to an embodiment of the present invention. As shown in FIG. 8, the distance between the upper and lower electrodes is reduced according to the magnitude of the applied load, thereby increasing the output. 8, the output has a linear characteristic with respect to the applied load. As described above, since the present invention has a linear output according to the applied load, at least three control signals may be output using one sensor. That is, the moving speed of the object controlling to move in the corresponding direction may be controlled by using the value output from the sensor. That is, when the user applies a high load to the actuator, the movement speed of the above-described object may also be controlled to move quickly. As described above, the present invention outputs at least three output signals according to the load applied to the sensor, whereas the conventional capacitive sensor outputs only two signals.

In addition, the sensor proposed in the present invention requires a relatively small force such as a mobile phone by controlling the thickness of the upper electrode (elastic material such as SUS), the size of the sensor, the distance between the upper electrode and the lower electrode according to the application field In addition to the input device, it can be used as an input device in a field requiring a relatively large force such as a game machine. In addition, by filling a material such as an elastomer or silicone rubber of a high dielectric material rather than an air gap between two electrodes, it is possible to improve the feeling (feel) at the fingertips about the size of the output signal and the pressing.

9 shows a packaging method of a sensor according to an embodiment of the present invention. In order for the direction sensor to be applied to various fields such as a mobile terminal and a game machine, the packaging (housing) part is very important for the accurate operation of the sensor part with a stable structure.

In order to accurately align the sensor and the actuator, as shown in FIG. 9, alignment holes 910 and 920 are formed in the sensor and the actuator to facilitate alignment of the sensor.

10 is a diagram illustrating one example of the overall packaging of a direction sensor.

The sensor unit is connected to a control unit or a connector (see FIG. 9) 900 for signal processing to express an expression or direction of force using a signal from the sensor.

According to FIG. 10, the actuator for pressing the sensor part may be easily pressed using only a sensor part using a method such as injection using a material such as silicone, rubber, plastic, and polymer so as to easily press the center part of each sensor. Can be produced with Alternatively, a material such as rubber, epoxy, polymer, or the like may be formed on top of an elastic electrode through a dispensing process.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the present invention .

300: lower electrode portion 310: cavity forming portion
320: upper electrode portion 330: actuator

Claims (6)

A lower electrode portion forming an electrode;
An upper electrode portion forming an electrode at a position corresponding to the electrode formed on the lower electrode portion;
A cavity forming portion formed between the lower electrode portion and the upper electrode portion and forming a perforation at a position corresponding to the electrode formed on the lower electrode portion;
And an actuator formed on an upper end of the upper electrode part, the actuator forming a protrusion at a position corresponding to an electrode formed on the upper electrode part of the lower surface.
The sensor of claim 1, wherein a protrusion is formed at an upper end of the cavity forming part, and a hole is formed at a position corresponding to the protrusion at a lower end of the upper electrode part.
The capacitive sensor of claim 2, wherein the capacitance between the upper electrode portion and the lower electrode portion increases linearly with the magnitude of the load applied to the upper electrode portion.
4. The capacitive sensor according to claim 3, wherein at least one of polymer, silicone, rubber, gel, and glycerin is filled in the perforated portion formed in the cavity forming portion.
The method of claim 3, wherein the upper electrode portion,
And a conductive material is plated at a position corresponding to an electrode formed in the lower electrode of the lower end of the substrate having a non-conductive material.
Forming an electrode on the lower electrode portion;
Stacking a cavity forming part having a perforation formed at a position corresponding to an electrode formed at the lower electrode part on an upper end of the lower electrode part;
Stacking an upper electrode part on which an electrode is formed at a position corresponding to an electrode formed on the lower electrode part on an upper portion of the cavity forming part;
Stacking an actuator having a protrusion formed at a position corresponding to an electrode formed on the upper electrode part of a lower surface of the upper electrode part;
And a protrusion formed at an upper end of the cavity forming portion, and a hole formed at a position corresponding to the protrusion at a lower end of the upper electrode portion.

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