KR20150117789A - Keypad for the Capacitive Touch Screen - Google Patents

Abstract

In a structure for mounting a keypad to a cover of a protection case of a smart phone mounting a capacitive touch screen, a keypad structure for covering a protection case of a structure of generating a signal in a touch screen when pressing a keypad, and generating the conductivity when pressing the keypad after being electrically insulated in up-down direction to generate a different touch screen signal in a state of pressing the keypad compared to a state of only touching the keypad.

Description

[0001] The present invention relates to an electrostatic touch screen driving keypad,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a keypad mounted on a cover of a protective case of an electronic device in an electronic device such as a smart phone or a tablet equipped with an electrostatic touch screen panel (TSP). More specifically, And an electrostatic TSP for inputting touch coordinate information by sensing the coordinates of the pressed position in the TSP through interaction with the keypad.

Generally, electronic devices equipped with a touch screen, especially a smart phone or tablet, often have a separate protective case.

In this case, when the cover of the protective case is covered, the touch screen is not operated. Therefore, the cover is opened and the touch screen is directly operated to operate the smart phone.

Alternatively, the cover of the protective case may be made transparent so that the touch operation can be performed even when the cover is covered.

However, in this case, since the sensation of touching the touch screen does not have the feeling of clicking, it is not easy to accurately recognize the touch.

The keypad of the existing feature phone or the keyboard of the computer is equipped with a spring structure or a metal dome to enable actual pushing operation.

Accordingly, in the present invention, a keypad is provided on a cover of a protective case of an electronic device. When a keypad is pushed, a touch signal is generated on the touch screen when the keypad is pushed so that input can be performed. Such as a keypad of a feature phone, to make it easier to input letters, numbers, and the like.

The present invention relates to a protective case of an electronic device equipped with a touch screen panel, in which a keypad is mounted on a cover of a protective case. The keypad has a metal dome to enable clicks, .

In particular, in the state where the keypad is not pressed, a touch signal is not generated and a malfunction is not caused.

The present invention provides a case for a personal portable terminal having a capacitive touch panel that can easily input letters or numbers when a protective case is used in an electronic device equipped with an electrostatic touch screen and a structure and operation method of the keypad attached thereto do.

According to a preferred embodiment of the present invention, when a number key located on a cover of a protective case is pressed, a portion of the touch panel, which includes a metal dome and a pressing protrusion, To an adjacent portion of the key pressed by the keypad.

And to electrically isolate the portion of the keypad from the portion of the keypad that is in close contact with the surface of the touch screen.

In addition, it is electrically isolated from the portion of the smartphone touching the surface of the touch screen to the vicinity of the keypad without being pressed.

And to minimize a touch signal that may occur in a touch screen of a smartphone without being pressed.

The keypad is mounted on the cover of the protective case of the smartphone according to the present invention. The keypad is mounted on the cover of the protective case of the smartphone according to the present invention, and includes a pressing projection protruding from the metal dome and the metal dome, So that the touch signal is clearly distinguished from the state in which the keypad is pressed and the state before the keypad is pressed, thereby enabling the operation of the keypad to be accurately performed.

Figure 1 shows a typical smartphone drawing.
In Fig. 2, a general smartphone case is shown.
FIG. 3 is a view of a structure in which a keypad is frosted on a cover of a protective case of a smartphone manufactured by the present invention.
4 is a cross-sectional view of a conventional keypad structure, a metal dome, and a circuit board.
5 is a diagram showing a basic concept of the present invention.
6 is a structural view of a keypad module including a keypad and a metal dome structure according to the present invention.
7 is a plan view of the keypad film.
Fig. 8 shows the structure of the spacing plate.
9 shows a structure in which a metal dome is attached to the separating plate.
11 is a view showing a conductive portion formed on a lower pedestal plate.
12 is a view showing a metal button attached to the keypad film.
Fig. 13 is a diagram in which button portions are three-dimensionally different from each other.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments. For reference, the same numbers in this description refer to substantially the same elements and can be described with reference to the contents described in the other drawings under the above-mentioned rules, and the contents which are judged to be obvious to the person skilled in the art or repeated can be omitted.

FIG. 1 shows a general smartphone 100 and a screen for inputting a phone number 110 is shown as an example.

By touching each numeric character button 120, the touch screen 130 senses the position signal, and the letters or numbers of the pressed buttons are input.

A typical smartphone case is shown in Fig.

In many cases, the cover 210 of the smartphone protective case 200 includes a transparent window 220.

The caller is displayed when a call is received through the transparent window, and the call can be received by a touch or a swipe operation.

However, because the cover is covered, you can not make a call when the cover is closed.

FIG. 3 shows a structure in which a keypad is mounted on a cover of a protective case of a smartphone to be manufactured according to the present invention.

As shown in FIG. 3, the cover 210 of the protective case has a transparent window 220 and a keypad 300 having numbers and letters.

However, the keypad installed on the cover can not directly connect with the smartphone unlike the keypad used in the conventional feature phone.

Do not connect the keypad directly unless you are making it in the manufacturer of the smartphone.

Therefore, there is a need for a method of generating a keypad signal in a manner different from the conventional operation of the keypad.

FIG. 4 schematically shows a conventional keypad structure, a metal dome, a circuit board, and a cross-sectional view and an operation method thereof.

4 (a), the button 420 of the keypad 410 is attached to the film 440 having the silicon protrusion 430, which is generally formed by silicone molding.

The keypad generally refers to a button and a pushing protrusion attached to a film and film that supports a number of buttons and a number of buttons.

In some cases, a plurality of keys may be integrally formed of metal, or the keys may be integrally formed as a film.

In some cases, the protrusion of the keypad is formed directly on the metal dome, and the keypad may be a button and a film, a metal plate and a film attached thereto, or a film printed with a simple number or letter.

A metal dome 450 made of stainless steel or the like is disposed under the pushing protrusion, and the metal dome is adhered to the electronic circuit board 470, which is generally a PCB, while being adhered to the adhesive film 460.

At this time, the adhesive film 460 to which the metal dome is adhered is also adhered to the electronic circuit board to fix the metal dome.

The electronic circuit board 470 has a center electrode 471 as a copper foil and a rim electrode 472 and a metal dome 450 are fixed in contact with the rim electrode 472.

4B is a plan view of a portion of the electronic circuit board 470 in contact with the metal dome. The center electrode 471 and the rim electrode 472 are electrically insulated.

FIG. 4 (c) shows an operation state of the existing keypad when the button is pressed.

The center portion of the metal dome 450 pressed by the button 420 and the silicon protrusion 430 has the same effect as turning on the switch because the center electrode 471 of the electronic circuit board and the rim electrode 472 are in electrical contact with each other The release button generates a pressed signal.

However, the operation mechanism of the general keypad of FIG. 4 is operated when the electronic circuit board is provided and the board is connected to the circuit of the smart phone or the feature phone, but when the cover is applied to the cover of the protective case of the smartphone of the present invention, This method can not be used because the electronic circuit is not connected.

In order to solve the above problem, the present invention relates to a design capable of directly generating a signal through a keypad on a touch screen mounted on a smart phone.

Generally, the technical point of the touch screen signal generation is a comparison of the signal strength before and after the touch.

If the intensity of the signal before and after the touch is changed to a sufficient magnitude, it can be detected on the touch screen.

In a typical touch screen, this is not a problem because the touch screen is clearly distinguished from the non-touch case.

However, if there is a keypad on the cover of the protective case, a different strength of the signal is required.

When using a smartphone, touches are not performed on the screen of the smartphone until the operation is performed, but in the case of the cover of the protective case, a touch such as holding with a finger is generally performed.

Therefore, the intensity of the signal generated on the touch screen when the user simply touches the keypad of the cover and when the button is pressed must be significantly different from each other.

The difference in distance from the touch screen of the smartphone when touching is actually 0.2 - 0.3 mm, which is actually the height of the metal dome.

Therefore, these small differences can only cause small signal differences in touch signals.

In order to solve this problem, in the present invention, a keypad module is designed so that it can be converted into a structure in which electricity can pass through the upper and lower portions as shown in FIG. 5.

This is a different structure from that of a conventional metal dome of a keypad in which the center and the frame are electrically connected to each other.

5 is a view showing a basic concept of the present invention.

This drawing describes the basic operation principle of the present invention and differs from the actual production.

5 (a) has a button, a button 420 and a metal finger 510 are positioned below the button 420, a metal finger is positioned on the touch screen 130, and the button and the touch screen are separated by a pedestal 520 It is electrically insulated.

In this case, the amount of the radio wave signal 530 from the touch screen to the button becomes insignificant.

As shown in FIG. 5 (b), when the button is pressed, the button and the metal are all in contact with each other, and the structure is free of the air layer.

In particular, if the button is a metal, pressing the button causes electricity to be transmitted to the finger, so that the radio wave signal 530 from the touch screen passes through the finger and senses the touch signal.

The structure of the present invention has a structure in which the button is pressed electrically in the vertical direction from the touch screen.

6 shows a structure of a keypad according to the present invention.

The keypad and buttons are composed of a keypad film 610.

A pushing protrusion 620 is formed on the bottom of the keypad film.

The metal dome is pressed more easily by the pressing protrusion.

In the present invention, the pushing protrusion has electric conductivity.

In the past, the pushing protrusion merely used to press the metal dome. Therefore, an electrically insulating silicone rubber or the like was used.

In the present invention, as a function for smoothly transmitting a radio wave signal on a touch screen, a pushing protrusion is formed of a conductive material such as carbon powder, a metal powder or other carbon fiber, a metal fiber, a conductive nano material, .

When the pushing projection has electrical conductivity, it functions as a metal under the button of Fig.

7 is a plan view of the keypad film and the pushing projection.

Numerals and characters are formed on the front surface of the keypad film in the pressing portion 611 as shown in the plan view of FIG. 7 (a).

In some cases, a separate plastic or metal button may be attached to the keypad film.

A top view of the pressing protrusion formed on the back surface of the keypad film is shown in Fig. 7 (b).

Since the pressing protrusion 620 is formed corresponding to each pressing portion and the width of the pressing protrusion is narrow as about 0.5 mm to 1.5 mm, the adhesive force to the film may be weak, so that the pressing protrusion 620 is formed at the peripheral attaching portion 621 having a low height.

As described above, the pushing protrusions for electrically conductive radio signal channels in the touch screen according to the present invention are made of electrically conductive material by mixing carbon powder, metal powder, or other conductive polymer, .

Although the peripheral attaching portions of the pushing protrusions may be formed to be electrically insulated from each other, the pushing protrusions may be formed as a whole to serve as a ground when the button is pushed.

7 (c), and the electrically conductive silicone rubber is adhered by the entire bonding portion 622. [

This is because, when the electrically conductive silicone rubber is attached to the film by molding, all of the pressing protrusions are electrically connected to each other.

The advantage of electrically connecting the push-out protrusion is that the touch function is performed by amplifying the touch signal by pressing the grounding function and pushing each button with the electric insulator.

The electrically conductive silicone rubber may be integrally molded together with the protruding portions in accordance with the above process by a method of electrically connecting the pressing protrusions. Alternatively, an electrically conductive ink may be printed on the film such as a carbon ink or a silver ink. And then each of the pushing protrusions can be electrically connected to each other.

When the pushing protrusions are electrically connected to each other, interference of the touch propagation signal may occur. Therefore, it is possible to print on the film, form an insulating layer, and then form pushing protrusions.

A sectional view of this structure is shown in Fig. 7 (d).

7D, a ground electrode layer 623 is formed on the keypad film 610 in whole or in part as an electrically conductive one.

The electrically conductive ground electrode layer may be formed by printing with carbon ink or silver ink, or may be coated with a thin film by E-beam evaporation or sputtering, or the metal plate may be directly bonded.

And a ground insulating layer 624 is formed thereon.

The forming method may be printing with an insulating ink or attaching a separate film.

Then, the electrically conductive pressing protrusion 620 is formed by molding.

In this structure, a signal is generated while the radio wave signal is transmitted to the ground electrode layer through the pushing protrusion.

6, the metal dome 630 is located below the pushing protrusion.

Since the metal dome is usually made of stainless steel, it is electrically energized when it touches the pushing protrusion.

Therefore, in the production of the adhesive film 640 for fixing the metal dome to the substrate so that the metal dome and the pressing protrusion are in direct contact with each other, the contact dome 641 is formed in the upper end of the metal dome.

Its structure is shown in more detail in Fig.

A contact groove 641 is formed in the upper end portion of the metal dome of the adhesive film 640 surrounding the metal dome 630 as shown in the perspective views (a) and (b) of FIG.

As a result, the pressing projection directly contacts the metal dome.

6, a spacing plate 650 for separating the metal dome from the touch screen is formed under the metal dome.

The separating portion includes a separating plate 650 for separating the entire metal dome from the touch screen, including the edge of the metal dome.

The spacing separates the entire metal dome from the touch screen at regular intervals, including the edges of the metal dome, to minimize the influence of the signal on the touch screen's electrostatic signal by the metal dome.

As is known, electrostatic touch screens operate by radio signals, so that the touch material is minimized when the metal material is at a certain distance from the touch screen surface.

The function of the separating plate is to make the metal dome distant from the touch screen and electrically connect to the bottom of the separating plate when the metal dome is pressed so that the signal can be received at the position closest to the touch screen 130 do.

The detailed structure thereof is shown in Fig.

9 (a) is a plan view of the separating plate, in which the metal dome is adhered by the adhesive film, and the front surface of the separating plate 650 is electrically insulated from each other and is provided with a switch metal layer 651 at a position corresponding to the metal dome, .

The width of the switch metal layer 651 is formed to be smaller than the metal dome edge 631 indicated by a dotted line in the drawing, so that the switch metal layer 651 is not electrically contacted when the metal dome is not pressed.

This is because the switch metal layer makes contact with the switch metal layer when the metal dome is pressed, thereby enabling on / off function to flow electricity.

A touch metal layer is formed on the separating plate near the touch screen.

Fig. 9 (b) shows the back surface which is the surface opposite to the surface to which the metal dome of the separating plate is attached.

A touch metal layer 652 is formed on the rear surface of the spacing plate.

The touch metal layer is a structure in which when a metal dome is pressed, a signal of a touch screen is connected to a pushing protrusion through a switch metal layer and a metal dome through a touch metal layer and is generated as a touch signal.

The size of the touch metal layer is determined by adjusting the intensity of the touch signal when the metal dome and the switch metal layer are in contact with each other by pressing the keypad.

Thus, the separating plate is formed with a connecting metal layer formed through the separating plate to connect the switch metal layer and the touchpad layer.

Fig. 9 (c) is a sectional view of the separating plate.

According to this figure, a switch metal layer 651 is provided on the upper portion of the separating plate 650, A touch metal layer 652 is provided. In order to electrically connect the touch metal layer 652, a hole is formed in the separating plate, and a metal layer is formed thereon to form a connection metal layer 653 connecting the switch metal layer and the touch metal layer.

FIG. 10 is a diagram showing a state before the keypad is pressed and a signal transmitted from the pressed touch screen.

As shown in FIG. 10A, even if the touch propagation signal 710 generated from the touch screen 130 is transmitted to the switch metal layer through the touch metal layer before the button is pressed, the touch signal is transmitted to the metal dome And does not generate a touch signal by returning to the touch screen.

Also, the touch propagation signal 711 generated at the edge of the metal dome is not transmitted to the metal dome due to the distance to the thickness of the separation plate, and is mostly returned to the touch screen and does not generate the touch signal.

In FIG. 10 (b), a case where the button is pressed and the metal dome is brought into contact with the switch metal layer is shown.

When the metal dome is brought into contact with the switch metal layer, the touch propagation signal 712 from the touch screen is absorbed into the touch metal layer, the connecting metal layer, the switch metal layer, the metal dome and the electrically conductive pressing protrusion, .

According to the structure of the present invention, when the keypad is installed on the cover of the case of the smartphone, the touch signal can be generated by pressing operation to operate the smartphone.

As shown in FIG. 6, a lower support plate 660, which serves as a cover, is formed under the spacing plate and supports the spacing plate.

The lower support plate may be adhered to the touch metal layer of the spacing plate by an electrically conductive adhesive 661 or the like.

11 shows a structure in which the electrically conductive pressing projection is formed on a metal dome rather than a keypad film.

Since the pressing projections are formed directly on the metal dome, electrical contact between the metal dome and the pressing projection is smooth.

As shown in Fig. 11, a contact conductive layer 612 is formed on the keypad film 610 at a position in contact with the pushing projection.

The contact conductive layer increases the electrical contact between the pushing projection and the keypad film.

As shown in the figure, the pressing protrusion 620 is formed in the metal dome 630, and the adhesive film 640 covering the metal dome and attached to the substrate has a contact dent in the portion where the pressing protrusion is formed in the metal dome, The pushing projection directly contacts the dome.

In some cases, if there is no problem with the touch signal, the adhesive film may be entirely covered on the metal dome without forming contact grooves, and the electrically conductive pressing projection may be formed thereon by molding.

If the thickness of the adhesive film is as thin as 0.1 mm, the signal may pass through the insulator while minimizing the signal loss, so that a signal may be generated. However, direct contact with the signal can further reduce the signal attenuation.

12 shows a structure in which a metal button 720 is attached as a button on the top of the keypad film.

In general, the film is electrically insulative, so that attenuation of the touch signal occurs.

To improve this, a metal button can be attached to the keypad film to increase the signal.

A through hole 613 is formed in the keypad film 610, and the metal button is connected to the pressing projection through the through hole.

In this structure, a method may be devised in which a contact conductive layer is formed of metal or the like on the lower part of the keypad film, and a metal button and an electrically conductive adhesive or the like are bonded.

Another advantage of the structure of mounting the keypad on the cover of the case of the smartphone according to the present invention is that the position of the number can be known only by touch.

As shown in FIG. 13, the buttons 614 formed on the keypad film 610 may have different shapes and three-dimensionally protrude so that the position of the buttons can be known by the touch. Thus, have.

The conventional touch screen of the smart phone is operated by a touch, and it is impossible to perform such a method because it is a glass surface. However, since the keypad is operated only by pressing, it is possible to touch the touch screen.

Therefore, it can be said that the invention of the present invention which operates by the interaction of the keypad and the touch screen of the smartphone is effective.

Although the present invention has been described with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the following claims. It can be understood that

100: Smartphone 110: Phone number input screen
120: numeric character button 130: touch screen
200: Protective case 210: Cover
220: Transparent window
300: Keypad
410: keypad 420: button
420: silicon protrusion 440: film
450: Metal dome 460: Adhesive film
470: electronic circuit board 471: center electrode
472:
520: pedestal 530: radio signal
610: keypad film 620: pushing projection
611: pressing portion 621: peripheral attachment portion
630: Metal dome 640: Adhesive film
641: contact groove 650: spacing plate
651: switch metal layer 631: metal dome edge
652: touch metal layer 653: connecting metal layer
660: Lower support plate 661: Adhesive
612: contact conductive layer 613: through hole
614:
710: Touch propagation signal 711: Touch propagation signal
712: touch propagation signal 720: metal button

Claims (9)

A keypad mounted on a cover of a protective case of an electronic device equipped with an electrostatic touch screen,
A keypad film,
A pressing protrusion made of an electrically conductive material formed on the keypad film,
A metal dome which is in contact with the pressing protrusion and is pressed,
An adhesive film adhering a metal dome and having a contact groove at a portion where the metal dome and the pressing projection contact,
A separating plate supporting the metal dome and adhered to the metal dome as an adhesive film,
A switch metal layer formed on a surface of the spacing plate corresponding to the metal dome and electrically insulated from the edge of the metal dome, the switch metal layer being formed at a position in contact with the metal dome when the metal dome is pressed;
A touch metal layer formed under the spacing plate,
A structure in which a connection metal layer for electrically connecting the switch metal layer and the touch metal layer of the spacing plate is formed,
And a lower support plate is formed at a lower portion of the separating plate.
The method of claim 1, wherein
Wherein a size of the switch metal layer at a portion where the metal dome of the separating plate is attached is smaller than an outer diameter of the metal dome. The method according to claim 1,
And the lower support plate is attached with an electrically conductive adhesive so as to correspond to each touch metal layer. The pressure-sensitive adhesive sheet as claimed in claim 1, wherein the adhesive portion for sticking the pressing protrusion to the keypad film is formed by pressing the electrically conductive silicone rubber into the pressing protrusion and the entire adhesive portion so that each pressing protrusion is electrically connected Features a smartphone protective case formed on the cover. The keypad according to claim 1, wherein the adhesive portion for sticking the pressing projection to the keypad film electrically conductively prints on the keypad film so as to electrically connect the respective pressing projections, and then forms the electrically conductive pressing projection Smartphone protection case. The method as claimed in claim 1, wherein, when the adhesive portion for adhering the pressing protrusion to the keypad film forms the pressing protrusion, the electrically conductive ground layer is formed on the keypad film by electro-conductive printing, metal thin film coating or metal plate, Wherein the cover is formed with a conductive pad and a conductive protruding portion is formed thereon. A metal button is attached to the top of the keypad film,
The keypad film has a through-hole formed below the metal button,
And the protrusion is electrically connected to the pushing protrusion through the through hole. A keypad mounted on a cover of a protective case of an electronic device equipped with an electrostatic touch screen,
Keypad film and.
A contact conductive layer formed on the keypad film and in electrical contact with the pushing projection,
A pressing protrusion formed directly on the metal dome,
An adhesive film adhering a metal dome and having a contact groove at a portion where the metal dome and the pressing protrusion are adhered,
A separating plate supporting the metal dome and adhered to the metal dome as an adhesive film,
A switch metal layer formed on a surface of the spacing plate corresponding to the metal dome and electrically insulated from the edge of the metal dome, the switch metal layer being formed at a position in contact with the metal dome when the metal dome is pressed;
A touch metal layer formed under the spacing plate,
A structure in which a connection metal layer for electrically connecting the switch metal layer and the touch metal layer of the spacing plate is formed,
And a lower support plate is formed at a lower portion of the separating plate. A keypad mounted on a cover of a protective case of an electronic device having an electrostatic touch screen, characterized in that the three-dimensional shape of the buttons formed on the keypad film is formed differently corresponding to each number. case.

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