JP2006173025A - Key input device and method of suppressing operation force of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a key input device eliminating the influence of dust and being free from impairing the sense of operation of the buttons. <P>SOLUTION: A switch part, including a metal dome (103), is formed into a sealed structure for preventing dusts from intrusion from outside, and worsening in the operation feeling due to the sealed structure is prevented, by enlarging the volume of an air releasing passage (107. 110) and by lowering the pressure increase due to the compression of the air generated, when pressing down the metal dome. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a key input device, and more particularly, to a key input device such as a mobile phone and a method for suppressing an operation pressure thereof.

  2. Description of the Related Art Conventionally, as a key input device for a portable device or the like, a structure having an operation button unit in which a conductive plate-like leaf spring (metal dome) is attached to an electrode pattern for a switch on a substrate with an adhesive sheet is known.

  FIG. 9 is a diagram showing a cross section of an operation button portion of a conventional key input device. As shown in FIG. 9A, a wiring board (substrate) 903 having an annular electrode pattern insulated from each other and a circular electrode pattern 906 inside thereof, a metal dome 901 mounted on the annular electrode pattern, The adhesive film sheet 902 has a metal dome 901 attached to a substrate 903, and an operation button 904 disposed on the adhesive film sheet 902.

  When the operation button 904 is pressed, the key input device has a switch function in which the top of the metal dome 901 is bent in the opposite direction and is in contact with the circular electrode pattern as shown in FIG. To fulfill.

  However, since the space under the metal dome 901 is sealed by the adhesive film sheet 902, the substrate 903, etc., when the metal dome 901 is pushed by the operation button 904, the sealed space is crushed and the key input device The air in the lower part of the dome 901 is compressed as it is, resulting in a sudden pressure increase, and this pressure increase becomes a resistance to the button operation force and causes a deterioration in the operational feeling.

  FIG. 10 shows a key input device that improves the deterioration of the operational feeling of a conventional key input device. 10A is an upper front view, and FIG. 10B is a cross-sectional view (see Patent Document 1 and FIG. 6). The film sheet 902 for attaching the metal dome 901 to a predetermined position has a structure in which a part of the edge of the metal dome of the film sheet 902 is cut out to provide an air hole 1003 that communicates with the outside. With this structure, when the metal dome 901 is pressed, the air under the metal dome 901 is discharged through the air hole 1003, so that the operational feeling is improved.

JP 2002-270062 A (FIG. 6)

  The conventional key input device shown in FIG. 10 is provided with an air hole 1003. As a result, each time the operation button is operated, the metal dome 901 causes air to enter and exit, and accompanying this, external dust or the like passes through the air hole 1003. The air is sucked into the space below the metal dome 901, and conduction between the metal dome 901 and the wiring pattern is impaired.

FIG. 11 is a diagram showing countermeasures against poor conduction due to dust or the like. In the configuration of the key input device shown in FIG. 8, as a countermeasure against conduction failure due to intrusion of dust or the like, the contact pressure at the contact location is increased by providing one or more protrusions 1102 on the conductive contact surface on the wiring pattern side of the metal dome 1101. Make it less susceptible to dust and other effects.
However, in a conventional key input device having an air hole, even if a metal dome protrusion is provided, the entry of dust or the like cannot be prevented at all. Therefore, the electrical switch characteristics are deteriorated and the conduction failure is completely prevented. It is difficult.

(the purpose)
An object of the present invention is to provide a key input device that eliminates the influence of dust on the key operation unit and does not impair the feeling of button operation, and a method for suppressing the operation pressure of the key input device.

  The present invention relates to an apparatus and method that eliminates the influence of dust and the like in a sealed space and that does not impair the feeling of button operation, and is a sealed space that causes air escape under the metal dome when the metal dome is pressed. Form. Specifically, a hole penetrating the wiring board under the metal dome is provided to provide air escape, and the hole penetrating the wiring board is sealed with a double-sided adhesive sheet and a frame or film.

  An air escape space is provided on the metal dome surface side of the wiring board. Specifically, silk printing is performed on the metal dome surface side of the wiring board, or a spacer sheet is attached to the wiring board and sealed with an adhesive film sheet.

  In particular, as a preferable specific example of the air escape path in the space of the metal dome when the operation button is pressed, a sealed passage leading to the space of the metal dome arranged immediately below another operation button is installed, and the air escape The space is composed of the sealed passage and the space directly below another operation button, the air escape space is isolated from the outside, and other specific examples are the installation of an air reservoir in the area around the metal dome space. And a combination of an air reservoir and the sealed passage, and a combination of an air reservoir, the sealed passage and the space of another metal dome.

  An operation pressure suppression method for a key input device according to the present invention is a method for suppressing an operation pressure of a key input device in which a key switch having a metal dome on an upper surface of a wiring board is hermetically sealed with a flexible sheet. It is characterized in that the operation pressure of the key switch is reduced by forming a sealed space for air escape.

  The air escape space is formed by providing a hole penetrating the wiring board under the metal dome and sealing with a double-sided adhesive sheet on the lower surface of the wiring board and a frame on the lower surface of the double-sided adhesive sheet, or the metal dome A hole penetrating the lower wiring board is provided, and the hole penetrating the wiring board is sealed with a double-sided adhesive sheet on the lower surface of the wiring board and a film on the lower surface of the double-sided adhesive sheet, or a metal dome of the wiring board It is provided on the arrangement surface side, or is formed by performing silk printing on the upper surface of the wiring board except for at least a region corresponding to the space of the metal dome and the air escape space connected to the space.

(Function)
In a key input device in which a key switch with a metal dome on the wiring board is sealed with a flexible sheet, the capacity of the air escape path is taken as a countermeasure against the deterioration of the operational feeling by making the sealed structure so that dust does not enter from the outside. The pressure rise due to air compression when the metal dome is pressed down is kept low, and the feeling of operation is prevented from deteriorating.

  According to the present invention, since the sealed passage is formed between the sealed spaces in which a plurality of metal domes are accommodated, the pressure increase in the space due to pressing of a specific operation button escapes to the sealed passage and other spaces. The operation pressure due to the pressure increase in the space of the metal dome can be suppressed, and a suitable operation feeling is realized.

  In addition, since the space under the metal dome is sealed with an adhesive film sheet and a wiring board, it is possible to completely prevent water and dust from entering from the outside. Etc. need not be applied.

  Further, the air escape space with respect to the sealed space in which the metal dome is accommodated can be formed by forming a sealed passage such as a groove in the spacer sheet on the upper surface side of the substrate or the frame on the lower surface side. The addition is unnecessary, and an increase in the thickness of the key operation unit can be suppressed.

  In particular, the degree of relaxation of the pressure increase can be increased almost in proportion to the volume of the air escape space such as the groove, the through hole, and the air reservoir, so that the size of the cross section of the groove, the through hole, and the air reservoir is increased. By adjusting the length, length, and shape, it is possible to adjust the degree of relaxation of the pressure rise, suitably relieve the deterioration of the operational feeling, and realize the optimum operational feeling.

(Embodiment 1)
(Description of configuration)
FIG. 1 is a diagram showing a configuration of a key input device according to a first embodiment of the present invention. This embodiment is a diagram showing an example of a key input device provided in a lower casing of a mobile phone, and is an exploded perspective view of the lower casing in which a key operation unit of the mobile phone is arranged.
The lower casing of the cellular phone in which the key operation unit is accommodated is configured by the front cover 101 and the rear cover 115 engaging with each other. Inside the lower housing, a circuit board 114 is provided on the back cover 115 side, and a key operation unit is provided on the circuit board 114 via an insulating sheet 113.

  The key operation unit has a laminated structure including an operation button 102, an adhesive film sheet 104, a metal dome 103 (111), a wiring board 105, a double-sided adhesive sheet 108 and a frame 109. Here, the metal dome 103 is attached to a predetermined position of the wiring board 105 by the adhesive film sheet 104. Hereinafter, the structure of the lower housing and the structure of the key operation unit will be described in detail.

  The front cover 101 is arranged in the longitudinal direction of the casing in which an operation button that allows button operation in the state in which the cellular phone is opened is inserted in addition to a hinge portion that is hinged by an upper casing (not shown) and a hinge shaft. It has a plurality of openings in rows. The back cover 115 has a battery housing part or the like on the outside, a circuit board 114 is arranged on the inside, and a frame 109 of a key operation part is arranged on the circuit board 114 via an insulating sheet 113.

  In this embodiment, three rows of grooves 110 are formed on the upper surface side of the frame 109 so as to correspond to the three rows of operation buttons in the longitudinal direction of the housing, and wiring is provided on the upper surface by the double-sided adhesive sheet 108. A substrate 105 is affixed, and a metal dome 103 is arranged on the upper surface of the wiring substrate 105 at the position of each wiring pattern 106 (112) to form a key switch. The upper surface of the wiring substrate 105 and the metal dome 103 An adhesive film sheet 104 is attached so that a space for accommodating the key switch is formed by the lower surface.

  Here, in the double-sided pressure-sensitive adhesive sheet 108 attached to the wiring board 105 and the lower part thereof, a through hole 107 is formed between the groove 110 and a space for accommodating the key switch in the upper part thereof.

  On the adhesive film sheet 104, a flexible sheet made of plastic, rubber or the like is formed with operation buttons 102 made of a plurality of protrusions made of a hard material that fits into the opening of the surface cover 101. Is placed.

  Further, the groove 110 provided in the frame 109 extends so as to communicate with another through hole 112 immediately below another metal dome 111. The periphery of the groove 110 is all isolated from the outside by a double-sided adhesive sheet 108 that tightly fixes the wiring board 105 and the frame 109.

  As described above, a space is formed between the plurality of switch electrodes formed of the wiring pattern 106 of the wiring board 105 and the metal dome 103 by the adhesive film sheet 104 adhered thereon, and the corresponding portion of the wiring board 105 is also formed. A space is formed in the groove 110 of the frame 109 immediately below by the double-sided adhesive sheet 108, and the space above and below the wiring substrate 105 are connected by the through hole 107 (112) to form a sealed space.

(Description of operation)
FIG. 2 is a diagram illustrating the key input device according to the present embodiment. 2A is a cross-sectional view showing the operation of the operation button, and FIG. 2B is a plan view showing the arrangement of the grooves 110 installed in the frame 109 and the arrangement of the double-sided pressure-sensitive adhesive sheet 108 that fixes the frame 109. is there.
In the cellular phone, when the operation button 102 is pressed, the metal dome 103 is deformed and the predetermined function assigned to the operation button 102 is realized by the contact conduction of the wiring pattern 106.

  In the present embodiment, the space immediately below the metal dome 103 is isolated from the outside by the adhesive film sheet 104, the wiring pattern 106, the double-sided adhesive sheet 108, and the frame 109. For this reason, when the operation button 102 is pressed, the air on the wiring pattern side of the metal dome 103 is compressed, and the compressed air escapes to the groove 110 through the through hole 107. This suppresses a rapid pressure increase and alleviates the deterioration of the operational feeling. In this example, only the spaces corresponding to the two metal domes are connected by air escape, but it is possible to add groove routing so that more metal domes can be connected.

(Embodiment 2)
In the first embodiment, an example in which a through hole is provided in a double-sided pressure-sensitive adhesive sheet attached to the wiring board and the lower part thereof and communicated with a groove formed in the frame is shown. A second embodiment in which the groove structure is formed without using it will be described below.

  FIG. 3 is a diagram showing the configuration of the key input device according to the second embodiment of the present invention. In this embodiment, a wiring board 305 that can also be used as a circuit board having a wiring pattern 306 such as a switch electrode formed on the upper surface is provided in the back cover 309, and the key operation unit is provided below the front cover 301. The laminated structure is composed of a flexible sheet having operation buttons 302, an adhesive film sheet 304, a metal dome 303, a spacer 307, and the wiring board 305. The metal dome 303 is attached to a predetermined position of the wiring board 105 by the adhesive film sheet 304. ing.

  In the present embodiment, a spacer sheet (projecting from the wiring pattern 306 as shown in the enlarged view of FIG. 3 in a peripheral area of the wiring pattern 306 provided on the wiring substrate 305 immediately below the metal dome 303. By providing the spacer 307, a groove 308 and the like are formed on the upper surface side of the wiring substrate, and the groove 308 is isolated from the outside by an adhesive film sheet 304 adhered and stuck on the metal dome 303.

  FIG. 4 is a diagram showing a more detailed configuration of the second embodiment. 4A is a plan view of a configuration in which only two metal domes are connected by a groove, and the shapes of the metal domes 303, the wiring patterns 306, the spacers 307, etc. on the wiring board in a state where the adhesive film sheet 304 is removed, The arrangement configuration is shown.

  4B is a cross-sectional view, and a spacer 307 having a predetermined pattern is formed so as to protrude from the wiring pattern 306 in a region around the wiring pattern 306 of the wiring board immediately below the metal dome 303 as shown in FIG. By being provided, a groove 308 is formed. The groove 308 forms a space isolated from the outside by the adhesive film sheet 304, the spacer 307, and the wiring substrate 305.

  In this example, the circular groove 305 connected to the space under the metal dome is formed around the wiring pattern 306 constituting the switch electrode, and the spacer 307 is formed so as to form the groove 308 between the adjacent grooves 305. An opening is provided.

  There are two methods for installing the spacer 307: silk printing and film sheet pasting. In this example, only the space under the two metal domes is connected by air escape, but it is possible to connect more spaces under the metal domes.

(Embodiment 3)
Since the degree of pressure increase under the metal dome when the operation button is pressed differs depending on the volume of the groove or the like, the operation feeling of the operation button can be more suitably set by adjusting the volume.

  FIG. 5 is a diagram showing a third embodiment of the present invention. The shapes and configurations of the metal dome 503, the wiring pattern 506, the spacer 507, etc. on the wiring board in a state where the adhesive film sheet is removed are shown. The laminated structure of the key operation unit is the same as that of the second embodiment (FIG. 4), but an air pocket 510 is formed by an opening pattern provided in the spacer 507 in an arbitrary region between two adjacent metal domes. Is.

  A circular groove connected to the space under the metal dome is formed around the wiring pattern 506 constituting the switch electrode, and a groove 508 is formed in an oblique direction from the space under the adjacent metal dome, and air connected to the groove 508 is further formed. An opening is provided in the spacer 507 so as to form the reservoir 510.

  By forming the air reservoir 510, the pressure increase under the metal dome when the operation button is pressed is further reduced, so that the operation feeling of the operation button can be optimally adjusted.

(Embodiment 4)
In the first embodiment, instead of using a frame as a groove structure formed on the lower side of the wiring board, a groove structure may be formed by a film sheet and a double-sided pressure-sensitive adhesive sheet for attaching the film sheet to the wiring board. it can.

  FIG. 6 illustrates a key input device according to the fourth embodiment. FIG. 6A is a cross-sectional view of the operation button unit, and FIG. 6B is a plan view of a double-sided sheet on the side opposite to the metal dome 603 with the film sheet 609 removed. The space immediately below the metal dome 603 is a space that is isolated from the outside by the adhesive film sheet 608, the wiring substrate 605, the double-sided adhesive sheet 608, and the film sheet 609.

  The key operation unit of the present embodiment has a laminated structure including an operation button 602, an adhesive film sheet 604, a metal dome 603, a wiring substrate 605 on which a wiring pattern 606 such as a switch electrode is formed, a double-sided adhesive sheet 608 and a film sheet 609. It becomes. The metal dome 603 is attached to a predetermined position of the wiring board 605 by an adhesive film sheet 604, and the film sheet 609 is attached to the back surface of the wiring board 605 by a double-sided adhesive sheet 608.

  Further, a through hole 607 is formed in the wiring board 605 from a space immediately below the metal dome 603, and a circular opening including the position of the through hole 607 and the circular openings are connected to the double-sided adhesive sheet 608. An opening pattern of the groove 610 is formed.

  The cellular phone according to the present embodiment realizes a predetermined function assigned to the operation button 602 by pressing the operation button 602 to deform the metal dome 603 and bring the wiring pattern 605 into contact conduction.

  When the operation button 602 is pressed, the air on the wiring pattern side of the metal dome 603 is compressed. The compressed air passes through the through hole 607 and escapes to the groove 610 and is directly below the metal dome 603 of another operation button connected to the groove 610. Since the sudden pressure rise is suppressed by escaping to the space, it is possible to mitigate the deterioration of the operational feeling due to the sealing of the metal dome.

  According to the fourth embodiment, it is possible to omit the use of the frame, and it is easy to manufacture the groove. Further, when the operation button is pressed, the film is added to the space below the other operation buttons. Due to the flexibility of the sheet 609, a sudden pressure increase can be suppressed by the circular opening pattern and the groove.

(Embodiment 5)
In the above embodiment, the example in which the spaces under the plurality of metal domes are connected via the grooves has been shown. However, the present invention provides a rapid pressure increase by providing air vents in the spaces under the metal domes. It is not necessary to connect the spaces under the metal dome to each other, and according to the degree of suppression of the increase in pressure, the ends of the grooves and the through holes are sealed. Can be configured.

  FIG. 7 is a diagram showing a key input device according to the fifth embodiment of the present invention. In the configuration in which the through holes are provided in the wiring board of the first and fourth embodiments (FIGS. 1, 2, and 6), the through hole is provided at the position of the through hole of the double-sided pressure-sensitive adhesive sheet 708 to be attached to the opposite side of the wiring board. A larger opening 713 having a predetermined shape is provided, and a sealed space is formed by the through-hole 404 and the opening 713 by attaching a frame, a film sheet, or the like to the double-sided pressure-sensitive adhesive sheet 108.

The opening 713 of the double-sided pressure-sensitive adhesive sheet 708 can have any shape and size as shown in FIG. 7B. In addition to the opening of the double-sided pressure-sensitive adhesive sheet 708, other metal can be used for the frame. Circular recesses and grooves independent of the space of the dome 703 (711) can also be formed. Further, the formation of an air escape that cannot be connected to the space under the other metal dome can be realized by using the spacers of the second and third embodiments (FIGS. 4 and 5).
(Other embodiments)
In the above embodiment, the operation button array configuration has been described with an example of three rows. However, it is clear that the operation buttons can be applied in any arrangement, and is provided on a frame, a double-sided adhesive sheet, a wiring board, or the like. The shape, structure, and number (number) of grooves, air pockets, and the like can also be realized by appropriately changing according to the arrangement of the operation buttons.

  FIG. 8 is a diagram showing a configuration example of the routing of the groove and the air reservoir according to the present invention. In FIG. 8 (a), the increase in the air pressure can be adjusted by extending the air escape groove 810 and the like on the back surface side of the wiring board. In FIG. This is a configuration example in which an opening of a tape or the like has a groove arrangement connected to one according to the arrangement of operation buttons, and a plurality of through holes are provided in the groove from the wiring board.

  The shape, structure, and number of the grooves and the air pockets described above can be arbitrarily provided individually or in common according to the function of the operation button in any of the embodiments.

It is a figure which shows the structure of the key input device of the 1st Embodiment of this invention. It is a figure which shows the key input device of this Embodiment. It is a figure which shows the structure of the key input device of 2nd Embodiment. It is a figure which shows the 2nd Embodiment of this invention. It is a figure which shows the 3rd Embodiment of this invention. It is a figure which shows the key input device of 4th Embodiment. It is a figure which shows the 5th Embodiment of this invention. It is a figure which shows the structural example of the routing of a groove | channel, and an air pocket. It is a figure which shows the cross section of the operation button part of the conventional key input device. This is a key input device that improves the deterioration of the operational feeling of a conventional key input device. It is a figure which shows the countermeasure against the conduction | electrical_connection defect by dust etc.

Explanation of symbols

101, 301 Front cover 102, 302, 602, 702, 904 Operation buttons 103, 111, 303, 603, 703, 901, 1101 Metal dome 104, 304, 604, 704, 902 Adhesive film sheets 105, 305, 605, 705 , 903 Wiring board 107, 112, 607, 707 Through hole 108, 608, 708 Double-sided adhesive sheet 109, 709 Frame 110, 308, 508, 610, 810 Groove 113 Insulating sheet 114 Circuit board 115, 309 Back cover 306, 606 Wiring Pattern 307 Spacer sheet (spacer)
503 Air hole 510 Air pool 609 Film sheet

Claims (19)

A key input device in which a key switch having a metal dome on the upper surface of a wiring board is sealed with a flexible sheet,
A key input device characterized in that a sealed space is formed as an air escape to the space of the metal dome.   The hole penetrating the wiring board under the metal dome is provided to provide air escape, and the hole penetrating the wiring board is sealed with a double-sided adhesive sheet and a frame on the lower surface of the wiring board. Key input device.   The hole penetrating the wiring board under the metal dome is provided to provide air escape, and the hole penetrating the wiring board is sealed with a double-sided adhesive sheet and a film on the lower surface of the wiring board. Key input device.   The key input device according to claim 1, wherein an air escape space is provided on a surface of the wiring board on which the metal dome is disposed.   In order to provide an air escape space in the wiring board, silk printing is performed on the upper surface of the wiring board except for at least the space of the metal dome and the area corresponding to the air escape space connected to the space. The key input device according to claim 4.   In order to provide an air escape space of the wiring board, a spacer having an opening in at least a space corresponding to the space of the metal dome and the air escape space connected to the space is attached to the upper surface of the wiring board. The key input device according to claim 4.   The key input device according to any one of claims 1 to 6, wherein the air escape space is constituted by a sealed passage provided between the space of another metal dome.   The key input device according to any one of claims 1 to 6, wherein the air escape space is constituted by an air reservoir formed in a peripheral region of the space of the metal dome.   The said air escape space is configured by an air passage formed in a peripheral region of the space of the metal dome and a sealed passage between the air sump. Key input device.   10. The key input device according to claim 1, wherein the key input device is provided in a key operation unit of a mobile phone. A method for suppressing the operating pressure of a key input device in which a key switch having a metal dome on the upper surface of a wiring board is sealed with a flexible sheet,
A method for suppressing an operation pressure of a key input device, comprising: forming a sealed space as an air escape to the space of the metal dome to reduce an operation pressure of a key switch.   The air escape space is formed by providing a hole penetrating the wiring board under the metal dome and sealing with a double-sided adhesive sheet on the lower surface of the wiring board and a frame on the lower surface of the double-sided adhesive sheet. 11. A method for suppressing an operation pressure of the key input device according to 11.   The air escape space is provided with a hole penetrating the wiring board under the metal dome, and the hole penetrating the wiring board is sealed with a double-sided adhesive sheet on the lower surface of the wiring board and a film on the lower surface of the double-sided adhesive sheet. The method for suppressing an operation pressure of a key input device according to claim 11.   12. The method for suppressing operating pressure of a key input device according to claim 11, wherein the air escape space is provided on the metal dome arrangement surface side of the wiring board.   The air escape space is formed by performing silk printing on the upper surface of the wiring board except for at least a space corresponding to the space of the metal dome and an air escape space connected to the space. 14. A method for suppressing an operation pressure of a key input device according to 14.   The air escape space is formed by attaching a spacer sheet having an opening in at least a space corresponding to the space of the metal dome and the air escape space connected to the space on the upper surface of the wiring board. Item 15. A method for suppressing an operation pressure of a key input device according to Item 14.   17. The operation pressure of the key input device according to claim 11, wherein the air escape space is formed as a sealed passage provided between other metal dome spaces. Method.   17. The method for suppressing operating pressure of a key input device according to claim 11, wherein the air escape space is formed as an air pool in a peripheral region of the space of the metal dome.   17. The air escape space is constituted by an air reservoir formed in a peripheral region of the metal dome space and a sealed passage between the air reservoir. A method for suppressing the operating pressure of the key input device.

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