WO2007114631A2

WO2007114631A2 - Key switch using magnetic force

Info

Publication number: WO2007114631A2
Application number: PCT/KR2007/001615
Authority: WO
Inventors: Young-Jun Cho
Original assignee: Young-Jun Cho
Priority date: 2006-04-03
Filing date: 2007-04-03
Publication date: 2007-10-11
Also published as: WO2007114631A3

Abstract

A key switch includes a base unit and a key-top unit. A number of contact terminal units are disposed on the base unit. The key-top unit moves vertically. The key-top unit includes an upper magnet attached to a bottom of the key-top unit. The base unit includes a lower membrane film on which a lower contact point is disposed; an upper membrane film on which an upper contact point that can be placed in contact with the lower contact point is disposed, and which is disposed above the lower membrane film; a spacer film which is interposed between the lower membrane film and the upper membrane film and includes a hole through which the upper contact point and the lower contact point can be placed in contact with each other; and a lower magnet which is fixed onto the upper membrane film and faces the upper magnet.

Description

KEY SWITCH USING MAGNETIC FORCE

[T Teecchhnniiccaall FFiieelldd]]

The present invention relates to a key switch of a keyboard unit which is used as an input device for a data processor, and, more particularly, to a key switch using permanent magnets to maintain a repulsive force.

[Background Art]

Data processors such as laptop computers, personal digital assistants (PDAs), desktop computers, and electronic calculators are generally equipped with input devices such as keyboards.

Conventional rubber dome keyboards typically use various materials such as rubber or synthetic resin or coil springs as elastic elements for providing an elastic force and/or restoring force. These elastic elements, however, may not function properly after long exposure to extreme environments such as highly humid or severely cold environments. In addition, the performance of elastic elements may decrease when strict quality control standards are applied to the manufacture of elastic elements, in view of exposure to an extreme environment which may affect the durability of elastic elements. In order to address this, key switches using the repulsive force between magnets have been developed. FIG. 1 illustrates a conventional key switch using the repulsive force between magnets, as disclosed in Japanese Patent Laid-Open Gazette No. 5-62561. Referring to FIG. 1, the key switch includes a supporting plate 13, a separator 12 which is disposed on the supporting plate 13, a key top 3, and magnets 14 and 15 which are disposed in the key top 3. Each of the magnets 14 and 15 may have one pole at an upper end and another pole at a lower end. For example, if the magnet 14 has a north pole at an upper end and a south pole at a lower end, the magnet 15 may have a south pole at the upper end and a north pole at the lower end such that the magnets 14 and 15 repel each other. When the key top 3 is pressed by a user and thus is lowered, a key shaft 4 which is included in the key top 3 is lowered into a key frame 7. Then, an upper membrane sheet 8, which is separated from a lower membrane sheet 10 by a spacer 9, is placed in contact with the lower membrane sheet 10 by the key shaft 4 to turn on the key switch. When the key switch is released, the key top 3 returns to its initial position by the repulsive force between the magnets 14 and 15, and, thus, the upper and lower membrane sheets 8 and 10 are detached from each other to turn off the key switch. However, the key switch illustrated in FIG. 1 may result in high manufacturing costs since it includes the separator 12 and a seating groove 15A for seating the magnet 15 and requires the installation of the magnet 15 into the seating groove 15 A.

Human fingers, however, have different strengths. Therefore, relatively weak fingers may get tired easily from prolonged typing. Therefore, it is necessary to develop cost-effective key switches that include fewer elements, and can provide comfortable typing by varying the amount of force required to activate each key according to which finger is supposed to hit the key.

[Disclosure] [ Technical Problem ]

In view of the above, it is an object of the present invention to provide a key switch that results in low manufacturing costs due to not having an addition seating groove for seating a plurality of magnets, and that provides comfortable typing by varying the amount of force required to activate each key. It is another object of the present invention to provide a key switch that reduces the size of a key input device, which is the most essential element for a portable key input device.

The object, features and advantages, of the present invention will become clear to those skilled in the art upon review of the following description, attached drawings and appended claims.

[Technical Solution]

According to an aspect of the present invention, there is provided a key switch using magnets, the key switch including a base unit and a key-top unit. A number of contact terminal units are disposed on the base unit, and generate an electrical signal by coming in contact with each other. The key-top unit receives a keystroke and moves vertically. The key-top unit includes an upper magnet which is attached to a bottom of the key-top unit. The base unit includes a lower membrane film on which a lower contact point is disposed; an upper membrane film on which an upper contact point that can be placed in contact with the lower contact point is disposed and which is disposed above the lower membrane film; a spacer film which is interposed between the lower membrane film and the upper membrane film and includes a hole through which the upper contact point and the lower contact point can be placed in contact with each other; and a lower magnet which is fixed onto the upper membrane film and faces the upper magnet. The upper magnet and the lower magnet provide a repulsive force to the key-top unit and the base unit.

According to another aspect of the present invention, there is provided a key switch using magnets, the key switch including a base unit and a key-top unit. A switch unit is disposed on the base unit and includes a first electrode and a second electrode that generate an electrical signal when being connected to each other. The key-top unit receives a keystroke and moves vertically. The key-top unit includes an upper magnet which is attached to a bottom of the key-top unit. The base unit includes a membrane film on which the first and second electrodes are disposed; a lower magnet which is disposed beneath the membrane film and faces the upper magnet; and a coating layer which fixes the lower magnet. The upper magnet and the lower magnet provide a repulsive force to the key-top unit and the base unit.

[Description of Drawings]

The above and other aspects and features of the present invention will become apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:

FIG. 1 illustrates a key switch using conventional magnets; FIG. 2 illustrates a device equipped with a keyboard unit;

FIG. 3 illustrates an exploded perspective view of a key switch using magnets, according to an embodiment of the present invention; FIG. 4 illustrates a cross-sectional view taken along line IVa-IVa' of FIG. 3;

FIG. 5 illustrates an operating state of the key switch illustrated in FIG. 3; FIG. 6 illustrates a cross-sectional view of a key switch using magnets according to another embodiment of the present invention;

FIG. 7 illustrates an operating state of the key switch illustrated in FIG. 6;

FIG. 8 illustrates a cross-sectional view of a key switch using magnets according to another embodiment of the present invention;

FIG. 9 illustrates an operating state of the key switch illustrated in FIG. 8;

FIG. 10 illustrates a keyboard which varies the amount of force required to type a key, according to the position of the key;

FIGS. 11 through 18 illustrate cross-sectional views of key switches using magnets according to other embodiment of the present invention;

FIG. 19 illustrates a cross-sectional view of a key switch using magnets according to another embodiment of the present invention;

FIG. 20 illustrates an operating state of the key switch illustrated in FIG. 19;

FIG. 21 illustrates a cross-sectional view of a key switch using magnets according to another embodiment of the present invention, the key switch including a stem unit which is disposed between a key-top unit and a key frame unit;

FIG. 22 illustrates an exploded perspective view of a key switch using magnets and crossed links according to another embodiment of the present invention;

FIG. 23 illustrates a cross-sectional view taken along line X a- X a' of FIG. 22; FIG. 24 illustrates an operating state of the key switch illustrated in FIG. 22;

FIG. 25 illustrates an exploded perspective view of a key switch using magnets, according to another embodiment of the present invention;

FIG. 26 illustrates a cross-sectional view taken along line IVa-IVa' of FIG. 25;

FIG. 27 illustrates an operating state of the key switch illustrated in FIG. 25; FIG. 28 illustrates a cross-sectional view of a key switch using magnets according to another embodiment of the present invention, the key switch having the same structure as the key switch illustrated in FIG. 25 except that it further includes a click-feel-generation unit;

FIG. 29 illustrates an operating state of the key switch illustrated in FIG. 28; FIG. 30 illustrates a cross-sectional view of a key switch using magnets according to another embodiment of the present invention, the key switch having the same structure as the key switch illustrated in FIG. 25 except that it further includes a stem unit disposed between a key-top unit and a key frame unit;

FIGS. 31 through 38 illustrate cross-sectional views of key switches using magnets according to other embodiments of the present invention;

FIG. 39 illustrates an exploded perspective view of a key switch using magnets and crossed links according to another embodiment of the present invention;

FIG. 40 illustrates a cross-sectional view taken along line Via- Ma' of FIG. 31 ;

FIG. 41 illustrates an operating state of the key switch illustrated in FIG. 39; and

FIG. 42 illustrates fixing an upper magnet to a key top.

<Description of reference numbers for main parts in drawings> 100, 100' : key-top unit 110: key top

120: key shaft 130: upper magnet

200: key frame unit 300, 300' : base unit

310: lower plate 320: lower membrane film

330, 330': upper membrane film 340: spacer film 350: contact terminal units 350a, 350b: first and second electrodes

360: lower magnet 370, 370': vinyl coating layer

380: coating layer 400: link unit

410: external link 420: internal link

[Mode for Invention]

The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Like reference numerals in the drawings denote like elements, and thus their description has been omitted.

Referring to FIG. 2, a keyboard unit 1 includes a plurality of key switches 2 and is used as a data-input unit. A key switch using magnets according to an embodiment of the present invention may be used in a keyboard device of a computer, but the present invention is not restricted to this. A key switch using magnets according to an embodiment of the present invention may also be used in an information processor such as a desktop computer, a personal digital assistant (PDA), a laptop computer, or an electronic calculator.

FIG. 3 illustrates an exploded perspective view of a key switch 10 using magnets according to an embodiment of the present invention, FIG. 4 illustrates a cross-sectional view taken along line IVa-IVa' of FIG. 3, and FIG. 5 illustrates an operating state of the key switch 10 illustrated in FIG. 3.

Referring to FIGS. 3 through 5, the key switch 10 includes a key-top unit 100 which a user touches, a key frame unit 200 which supports and guides the key-top unit 100, and a base unit 300 to which pressure is applied by the key-top unit 100.

The key-top unit 100 includes a key top 110 which is directly touched by the user and a key shaft 120. The key shaft 120 includes an upper magnet 130 therein. The upper magnet 130 maintains a predetermined repulsive force. A protrusion 123 is disposed at the end of the key shaft 120. The key frame unit 200 includes an inner wall 210. The key shaft 120 moves vertically along the inner wall 210. The protrusion 123 of the key shaft 120 may be engaged with an engaging recess 212.

The base unit 300 includes a lower membrane film 320 which is disposed on a lower plate 310 of a key input device, an upper membrane film 330, and a spacer film 340 which is interposed between the lower membrane film 320 and the upper membrane film 330 so that the lower membrane film 320 and the upper membrane film 330 can become a predetermined distance apart. A pair of contact terminal units 350 is disposed on the upper membrane film 330 and the lower membrane film 320. The contact terminal units 350 generate an electrical signal by coming in contact with each other by pressure. A lower magnet 360 is disposed on the upper membrane film 330, and corresponds to the upper magnet 130. The upper membrane film 330 is coated with a vinyl coating layer 370 so that the lower magnet 360 can be fixed onto the upper membrane film 330.

In order to generate and maintain a repulsive force between the upper magnet 130 and the lower magnet 360, the upper magnet 130 and the lower magnet 360 may be disposed so that the same magnetic poles of the upper magnet 130 and the lower magnet

360 face each other. The vinyl coating layer 370 may be optionally provided if the lower magnet 360 can be fixed onto the upper membrane film 330 by, for example, an adhesive. In order to firmly fix the lower magnet 360 onto the upper membrane film 330, the lower magnet 360 may be fixed onto the upper membrane film 330 by an adhesive, and then the upper membrane film 330 may be coated with the vinyl coating layer 370.

The vinyl coating layer 370 may be formed of synthetic resin such as a soft film, but the present invention is not restricted thereto. The corrosion or oxidation of the lower magnet 360 can be prevented by coating the lower magnet 360 with the vinyl coating layer 370 so that the vinyl coating layer 370 can adhere closely to the lower magnet 360.

If a user presses the key top 110, the key top 110 is lowered by a repulsive force between the upper magnet 130 and the lower magnet 360. If the key top 1 10 is lowered by more than a predetermined distance so that the contact terminal units 350 can be placed in contact with each other by the key shaft 120 or the upper magnet 130, an electrical signal corresponding to the key switch 10 may be generated. In order to prevent the upper magnet 130 from moving vertically inside the key shaft 120 when pressure is applied to the key shaft 120, a supporting column 122 may be included in the key top 110. When the user releases the key top 110, the key top 110 returns to its initial position by the repulsive force between the upper magnet 130 and the lower magnet 360. The key top 110 may be lowered to the extent that an inner top surface 112 of the key top 110 comes in contact with a top surface of the key frame unit 200. The key top 110 may be lifted to the extent that the protrusion 123 of the key top 110 comes in contact with the engaging recess 212 of the key frame unit 200.

A membrane switch unit having the contact terminal units 350 may include a thin circuit film. Specifically, the membrane switch unit includes the upper membrane film 330, the lower membrane film 320 and the spacer film 340 which is interposed between the upper membrane film 330 and the lower membrane film 320 and prevents a short circuit between the upper membrane film 330 and the lower membrane film 320. An electrode is disposed on the lower membrane film 320 and extends across a key top row including the key top 110, and the contact terminal units 350 are disposed on an upper circuit film. A hole 342 is formed through the spacer film 340 so that the contact terminal units 350 can be disposed in the hole 342. When the user presses the key top 110, the key top 110 is lowered and applies pressure to the upper membrane film 330. A contact point on the upper membrane film 330 is connected to a contact point on the lower membrane film 320 via the hole 342 so that a switch input can be recognized. In general, membrane switches are formed by printing conductive ink on a thin circuit film to lower the manufacturing cost. Therefore, less expensive keyboards can be designed using membrane switches.

FIG. 6 illustrates a cross-sectional view of a key switch 20 using magnets, according to another embodiment of the present invention, and FIG. 7 illustrates an operating state of the key switch 20 illustrated in FIG. 6. The key switch 20 has almost the same structure as the key switch 10 illustrated in FIGS. 3 through 5. Referring to FIGS. 6 and 7, the key switch includes a contact protrusion 140 which is disposed at the end of a key shaft 120. The contact protrusion 140 can enable a pair of contact terminal units 350 to firmly contact each other. The contact protrusion 140 may be formed of an elastic material such as rubber or synthetic resin. FIG. 8 illustrates a cross-sectional view of a key switch 30 using magnets, according to an embodiment of the present invention, and FIG. 9 illustrates an operating state of the key switch 30 illustrated in FIG. 8. The key switch 30 has the same structure as the key switch 20 illustrated in FIGS. 6 and 7 except that the key switch 30 includes a contact protrusion plate 150, instead of the contact protrusion 140. Specifically, the contact protrusion plate 150 is disposed on an upper membrane film 330. The contact protrusion plate 150 may be formed of an elastic material such as rubber or synthetic resin. The contact protrusion plate 150 may include a protrusion for each key switch 30. According to the embodiment of FIGS. 8 and 9, it is possible to easily obtain the same effect as in the embodiment of FIGS. 6 and 7 without the need to attach the contact protrusion 140 on an upper magnet 130.

FIG. 10 illustrates a keyboard that varies the amount of force required to type a key according to the position of the key. One of the latest high-end keyboard designs involves altering the amount of pressure required to activate a key according to which finger is supposed to hit the key, given that the amount of pressure that can be applied to register a keystroke varies from one finger to another. This technology is referred to as ErgoForce. In general, the fingers have different strengths. The thumb is usually the strongest finger, and the middle finger, the index finger, the ring finger, and the little finger are respectively the second strongest finger, the third strongest finger, the second weakest finger, and the weakest finger. Since most keyboards require the same force to activate each key regardless of whether the key is to be hit by user's weak or strong finger, little fingers may easily get tired from prolonged typing using such keyboards. The ErgoForce technology is characterized by altering the amount of pressure required to register each keystroke in consideration of the differences in strengths of the fingers. Referring to FIG. 10, there are five levels of force throughout the keyboard: 80, 60, 55, 45, and 35 grams. Specifically, the amount of force required to register a keystroke is 35 g for keys pressed by the little filter; 45 g for regular keys; 55 g for function keys and edit keys; 65 g for the Enter key; and 80 g for the spacebar, Alt key, and Ctrl key.

FIGS. 11 through 18 illustrate cross-sectional views of key switches 40, 41, 42, and 43 using magnets, according to embodiments of the present invention. In general, it is difficult to manufacture, using conventional magnets, key switches that are capable of easily adjusting pressure. Referring to FIGS. 11 and 12, the repulsive force between an upper magnet 130 and a lower magnet 360 may be adjusted by appropriately adjusting the thickness of a portion of an upper membrane film 330' that is disposed under the lower magnet 360 and the thickness of a portion of a vinyl coating layer 370' that covers the lower magnet 360. Specifically, referring to FIG. 11, the repulsive force between the upper magnet 130 and the lower magnet 360 may be increased by increasing the thickness of the portion of the upper membrane film 330' disposed under the lower magnet 360 so that the distance between the upper magnet 130 and the lower magnet 360 can be reduced to hi. Referring to FIG. 12, the repulsive force between the upper magnet 130 and the lower magnet 360 may be reduced by reducing the portion of the upper membrane film 330' disposed under the lower magnet 360 so that the distance between the upper magnet 130 and the lower magnet 360 can be increased to h2. In this manner, it is possible to easily and precisely adjust pressure for each key switch 40. The distance between the upper magnet 130 and the top surface of the portion of the vinyl coating layer 370' that covers the lower magnet 360 may be the same as a height / by which the portion of the vinyl coating layer 370' that covers the lower magnet 360 protrudes over the top surface of the remaining vinyl coating layer 370.

Alternatively, the distance between the upper magnet 130 and the lower magnet 360 may be adjusted by providing a magnet holder 130A inside the key shaft 120 without the need to adjust the thicknesses of the vinyl coating layer 370 and the upper membrane film 330, and this will hereinafter be described in further detail with reference to FIGS. 13 and 14.

Referring to FIG. 13, a magnet holder 130A may be disposed under an upper magnet 130 so that the distance between the upper magnet 130 and a lower magnet 360 can be increased to h3, and that the repulsive force between the upper magnet 130 and the lower magnet 360 can be reduced. Referring to FIG. 14, the magnet holder 130A may be disposed on the upper magnet 130 so that the distance between the upper magnet 130 and the lower magnet 360 can be reduced to h4, and that the repulsive force between the upper magnet 130 and the lower magnet 360 can be increased. In this manner, it is possible to easily and precisely adjust pressure for each key switch 41. Alternatively, referring to FIG. 13, the repulsive force between the upper magnet 130 and the lower magnet 360 may be adjusted by adjusting the bottom thickness of the magnet holder 130A. The magnet holder 130A may be formed of rubber or synthetic resin, but the present invention is not restricted to this.

Referring to FIGS. 15 and 16, a magnet holder 130A is disposed under an upper magnet 130 inside a key shaft 120 so that the upper magnet 130 can be contained in the magnet holder 130A. In this case, the repulsive force between the upper magnet 130 and a lower magnet 360 may be varied by varying the height of the upper magnet 130. If the upper magnet 130 is elongated, as illustrated in FIG. 16, a supporting column 122 that supports the magnet holder 130A may be shortened accordingly in consideration of the interference of the upper magnet 130 with the supporting column 120 so that the distance between the key shaft 120 and a vinyl coating layer 370 can be uniformly maintained. Thus, if the upper magnet 130 is short with a height of 11, as illustrated in FIG. 15, the repulsive force between the upper magnet 130 and the lower magnet 360 may become relatively weak. If the upper magnet 130 is tall with a height of 12, as illustrated in FIG. 16, the repulsive force between the upper magnet 130 and the lower magnet 360 may become relatively strong. In short, it is possible to easily and precisely adjust pressure for each key switch 42 by varying the height of the upper magnet 130. Referring to FIGS. 17 and 18, the repulsive force between a lower magnet 360 and which is contained in a magnet holder 130A may be varied by varying the size of the upper magnet 130. In this manner, it is possible to easily and precisely adjust pressure for each key switch 43.

In short, the amount of force required to activate the key switch 40, 41, 42, or 43 according to which finger is supposed to hit the key switch 40, 41, 42, or 43 may be varied by adjusting the thicknesses of the vinyl coating layer 370 and the upper membrane film 330 or by using the magnet holder 130A. However, the present invention is not restricted thereto.

FIG. 19 illustrates a cross-sectional view of a key switch 50 using magnets, according to another embodiment of the present invention, and FIG. 20 illustrates an operating state of the key switch 50 illustrated in FIG. 19. Referring to FIGS. 19 and 20, the key switch 50 has the same structure as the key switch 10 illustrated in FIG. 3 except that the key switch 50 further includes a click-feel generation unit 160 which provides a user with a click-feel.

Referring to FIGS. 19 and 20, when the user presses a key top 110, the key top

110 is lowered while being affected by the repulsive force between an upper magnet 130 and a lower magnet 360. If the key top 110 is lowered by more than a predetermined distance so that a pair of contact terminal units 350 comes in contact with each other by a key shaft 120 of the key top 1 10, an electrical signal corresponding to the key switch 50 may be generated. When the key top 110 is lowered, a repulsive force is generated between the upper magnet 130 and the lower magnet 360, and the click-feel generation unit 160 is bent by the key shaft 120 of the key top 110 so that the amount of pressure required to move the key top 110 can vary slightly. In this case, the click-feel generation unit 160 provides a click sound almost at the same time as the contact terminal units 350 comes in contact with each other, thereby enabling the user to sense the input of a keystroke. The click-feel generation unit 160 may be disposed inside a key frame unit 200. The click-feel generation unit 160 may be formed of an elastic metallic material and may be bent twice.

FIG. 21 illustrates a cross-sectional view of a key switch 60 using magnets, according to another embodiment of the present invention. Referring to FIG. 21 , the key switch 60 includes a stem unit 500 which is disposed between a key-top unit 100 and a key frame unit 200. Specifically, a key shaft 120 and a supporting column 122 of the key-top unit 100 and an upper magnet 130 which is fixed to the supporting column 122 are fixed inside the stem unit 500. The stem unit 500 may include a support 520 which extends beneath the upper magnet 130 and supports the upper magnet 130. The stem unit 500 may also include a protrusion 510 which is disposed at an end of the stem unit 500. The protrusion 510 serves the same functions as the protrusion 123 of the key shaft 120 in the embodiments of FIGS. 3 through 20. The key-top unit 100 is coupled to the stem unit 500 so that they can move along with each other. When key-top unit 100 is lifted, the protrusion 510 of the stem unit 500 is engaged with an engaging recess 212 of the key frame unit 200 so that the key-top unit 100 can be prevented from being detached from the key frame unit 200.

The stem unit 500 may be formed of polyacetal (POM). In this case, the stem unit 500 provides a comfortable key touch during the vertical movement of the key top 100. However, the stem unit 500 may be formed of a material other than that set forth herein. In short, it is possible to strengthen the connection between the upper magnet 130 and the key-top unit 100 and provide a user with a comfortable key touch by disposing the stem unit 500 between the key frame unit 200 and the key-top unit 100. In the embodiments of FIGS. 3 through 21, the key-top unit 100 is supported by the key frame unit 200. However, the key-top unit 100 may be supported by a number of links, instead of being supported by the key frame unit 200 which guides the key-top unit 100, and this will hereinafter be described in further detail with reference to FIGS. 22 through 24. FIG. 22 illustrates an exploded perspective view of a key switch 70 using magnets and crossed links according to an embodiment of the present invention, FIG. 23 illustrates a cross-sectional view taken along line X a- X a' of FIG. 22, and FIG. 24 illustrates an operating state of the key switch 70 illustrated in FIG. 22. In the embodiments of FIGS. 3 through 5 and 22 through 24, like reference numerals indicate like elements, and thus detailed descriptions thereof will be skipped. The key switch 70 illustrated in FIGS. 22 through 24 has almost the same structure as the key switch 10 illustrated in FIGS. 3 through 5.

Specifically, the key switch 70 includes a key-top unit 100' which is touched by a user, a link unit 400 which supports the key-top unit 100', and a base unit 300' to which pressure is applied by the key-top unit 100'. The key-top unit 100' includes a key top 110' which is directly touched by the user's finger and a key shaft 120. The key shaft 120 includes an upper magnet 130 therein. The upper magnet 130 maintains a predetermined repulsive force. The link unit 400 includes an external link 410, an internal link 420 which fits in the external link 410, and link fixing pivots 430 which couple the external and internal links 410 and 420 so that the external and internal links 410 and 420 can pivot on the link fixing pivots 430. As the key top 1 10 is moved up and down, the angles between a lower plate 310 of a key input device and the external and internal links 410 and 420 gradually increase or decrease, thereby driving the key switch 70. The repulsive force and restoration force may be generated for the key top 1 10' using the repulsive force between magnets.

The base unit 300 includes a lower membrane film 320 which is disposed on the lower plate 310, an upper membrane film 330, and a spacer film 340 which is interposed between the upper membrane film 330 and the lower membrane film 320 so that the upper membrane film 330 and the lower membrane film 320 can be a predetermined distance apart. A pair of contact terminal units 350 is disposed on the upper membrane film 330 and the lower membrane film 320. The contact terminal units 350 generate an electrical signal by coming in contact with each other by pressure. A lower magnet 360 is disposed on the upper membrane film 330 and corresponds to the upper magnet 130. The upper membrane film 330 is coated with a vinyl coating layer 370 so that the lower magnet 360 can be fixed onto the upper membrane film 330. In order to maintain a predetermined repulsive force between the upper magnet 130 and the lower magnet 360, the upper magnet 130 and the lower magnet 360 may be disposed so that the same magnetic poles of the upper magnet 130 and the lower magnet 360 can face each other.

A pair of lower fixing/supporting units 440 and a pair of lower slots 445 for supporting the external and internal links 410 and 420 are disposed on the lower plate 310. The lower fixing/supporting units 440 fix one side of the external link 410. The lower slots 445 support one side of the internal link 420 so that the internal link 420 can be moved laterally within the lower slots 445 when the key top 1 10' is lowered. The other side of the external link 410 is connected to an upper slot 175 which is disposed beneath the key top 110', and the other side of the internal link 420 is connected to an upper fixing/supporting unit 170 which is disposed beneath the key top 110'. In the embodiments of FIGS. 22 through 24, unlike in the embodiments of FIGS.

3 through 5, the key switch 70 includes a pair of links, i.e., the external and internal links 410 and 420, instead of the key frame unit 200, so that the key top 1 10' is supported and guided by the external and internal links 410 and 420.

Referring to FIGS. 22 through 24, when the user presses the key top 110', the key top 110' is lowered while being affected by the repulsive force between the upper magnet 130 and the lower magnet 360. Specifically, when the user presses the key top 110', the key top 110' is lowered, slightly tilting to the right by the external and internal links 410 and 420. Since the degree to which the key top 110' tilts to the right while being lowered is not considerable, the key top 110' may look as if it were vertically lowered. If the key top 110 is lowered to the extent that the contact terminal units 350 comes in contact with each other, an electrical signal corresponding to the key switch 70 may be generated. In order to prevent the upper magnet 130 from being vertically moved inside the key shaft 120 when pressure is applied to the upper magnet 130 by the key shaft 120, a supporting column 122 may be included in the key top 110'. When the user releases the key top 1 10', the key top 110' returns to its initial position due to the repulsive force between the upper magnet 130 and the lower magnet 360. The key top 110' may be lowered to the extent that the key top 110' is supported by the lower plate 310. The key top 110' may be lifted to the extent that the right sides of the external and internal links 410 and 420 are engaged with the far left of the upper and lower slots 175 and 445, respectively.

In the embodiments of FIGS. 22 through 24, the contact terminal units 350 come in contact with each other by the pressure from the key shaft 120. However, the contact terminal units 350 may come in contact with each other by the pressure from the contact protrusion 140 illustrated in FIG. 6 or from the contact protrusion plate 150 illustrated in FIG. 8.

FIG. 25 illustrates an exploded perspective view of a key switch 80 using magnets, according to another embodiment of the present invention, FIG. 26 illustrates a cross-sectional view taken along line IVa-IVa' of FIG. 25, and FIG. 27 illustrates an operating state of the key switch 80 illustrated in FIG. 25. Referring to FIGS. 25 through 27, the key switch 80 includes a key-top unit 100 which is touched by a user, a key frame unit 200 which supports the key-top unit 100, and a base unit 300 to which pressure is applied by the key-top unit 100. The key frame unit 200 and the key-top unit 100 are the same as their respective counterparts in the embodiment of FIGS. 3 through 5, and thus detailed descriptions have been omitted. The embodiments of FIGS. 25 through 27 will hereinafter be described in detail while stressing mainly the differences with the embodiments of FIGS. 3 through 5.

Referring to FIGS. 25 through 27, the base unit 300 includes a lower plate 310 which is used to seat the key frame 200 and a membrane film 320 which is disposed above the lower plate 310. In the embodiment of FIGS. 25 through 27, unlike in the embodiment of the FIGS. 3 through 5, the key switch 80 includes a single membrane film 320, instead of a pair of upper and lower membrane films 320 and 330. A lower magnet 360 is disposed beneath the membrane film 320, and corresponds to an upper magnet. The lower magnet 360 is coated with a coating layer 360, and thus can be fixed. A membrane switch unit 350 including a first electrode 350A and a second electrode 350B is disposed on the membrane film 320. The first and second electrodes 350A and 350B generate an electrical signal by coming in contact with each other. The first and second electrodes 350A and 350B may be formed by printing conductive ink on the membrane film 320. In order to generate and maintain the repulsive force between the upper magnet 130 and the lower magnet 360, the upper magnet 130 and the lower magnet 360 may be disposed so that the same magnetic poles of the upper magnet 130 and the lower magnet 360 can face each other. The coating layer 380 may be formed of a material having compressive force and elastic force such as synthetic resin, sponge, or expandable polystyrene (EPS). Therefore, the lower magnet 360 can be fixed by coating the lower magnet 360 with the coating layer 380 without the need to form a groove in the lower plate 310 for accommodating the lower magnet 360.

The coating layer 380 may be formed of synthetic resin such as a soft film, but the present invention is not restricted to this. It is possible to prevent the corrosion and oxidation of the lower magnet 360 by coating the lower magnet 360 with the coating layer 380 so that the coating layer 380 can be firmly attached to the lower magnet 360.

Referring to FIGS. 25 through 27, when the user presses the key top 110, the key top 110 is lowered while being affected by the repulsive force between the upper magnet 130 and the lower magnet 360. The key top 110 is lowered to the extent that the upper magnet 130, which is disposed at the end of the key shaft 120, comes in contact with the first and second electrodes 350A and 350B. Since magnets are highly conductive, an electrical signal generated by the membrane switch unit 350 is transmitted to the upper magnet 130 when the upper magnet 130 comes in contact with the membrane switch device 350.

The membrane switch unit 350 including the first and second electrodes 35OA and 350B may include a thin circuit film. In general, membrane switches are formed by printing conductive ink on a thin circuit film to lower the manufacturing cost. Therefore, less expensive keyboards are designed using membrane switches. The first and second electrodes 350A and 350B may be worn away after long use. In order to prevent this, a passivation layer 311 may be formed of carbon so that the first and second electrodes 350A and 350B can be coated with the passivation layer 311. In this manner, the durability of the first and second electrodes 350A and 350B can be increased. FIG. 28 illustrates a cross-sectional view of a key switch 80 using magnets, according to another embodiment of the present invention, and FIG. 29 illustrates an operating state of the key switch 80 illustrated in FIG. 28. The key switch 80 illustrated in FIG. 28 has the same structure as the key switch 80 illustrated in FIGS. 25 through 27 except that the key switch 80 illustrated in FIG. 28 further includes a click-feel generation unit 160. The click-feel generation unit 160 has already been described in detail, and thus a detailed description thereof has been omitted.

FIG. 30 illustrates a cross-sectional view of a key switch 80 using magnets, according to another embodiment of the present invention. The key switch 80 illustrated in FIG. 30 has the same structure as the key switch 80 illustrated in FIGS. 25 through 27 except that the key switch 80 illustrated in FIG. 30 further includes a stem unit 500. The stem unit 500 has already been described in detail, and, thus, a detailed description thereof will be omitted.

FIGS. 31 through 38 illustrate cross-sectional views of key switches 90, 91, 92, 93, and 94 using magnets, according to other embodiments of the present invention. The key switches 90, 91, 92, 93, and 94 may adopt almost the same methods of varying the repulsive force between an upper magnet and a lower magnet as in the embodiments of FIGS. 11 through 18. Specifically, referring to FIG. 31, a membrane film 320' may be formed to have a thickness of tl in an area where a lower magnet 360 is disposed. In this manner, it is possible to easily and precisely adjust the pressure of each key switch 90. In order to form the membrane film 320', a groove 371 may be formed in a coating layer 380'. Referring to FIG. 32, the degree of magnetization may be determined by where in a coating layer 380 a lower magnet 360 is located, and, particularly, by a distance t2 between the lower magnet 360 and a membrane film 320, rather than by the thickness of the membrane. In this case, it is possible to easily and precisely adjust the pressure of each key switch 91.

FIGS. 33 through 38 illustrate a way to adjust the repulsive force between an upper magnet 130 and a lower magnet 360 by varying the relative positions of the upper magnet 130 and a magnet holder 130A and/or adjusting the size and height of the upper magnet 130. The key switches 92, 93, and 94 illustrated in FIGS. 33 through 38 have the same structures as their respective counterparts illustrated in FIGS. 11 through 18, and, thus, detailed descriptions of the structures of the key switches 92, 93, and 94 will be omitted. Referring to FIG. 33, a magnet holder 130A may be disposed beneath an upper magnet 130 at the end of a key shaft 120. When a key top 110 is lowered, the magnet holder 130A is also lowered along with the key shaft 120. The magnet holder 130 may be formed of a highly conductive material in order to increase the transmission of an electrical signal generated by a first electrode 350A and a second electrode 350B. The magnet holder 130A may be formed of a conductive material such as copper, a copper alloy, aluminum, an aluminum alloy, steel, stainless steel, or a combination thereof so that an electrical signal can be input to a switch unit 350. However, the present invention is not restricted to this.

FIG. 39 illustrates an exploded perspective view of a key switch 100 using magnets and crossed links, according to another embodiment of the present invention, FIG. 40 illustrates a cross-sectional view taken along line VEIa- Ma' of FIG. 39, and FIG. 41 illustrates an operating state of the key switch 100 illustrated in FIG. 39. The key switch 100 illustrated in FIGS. 39 through 41 has the same structure as the key switch 80 illustrated in FIGS. 25 through 27, except that the key switch 100 further includes external and internal links 410 and 420. The external and internal links 410 and 420 have already been described in detail, and, thus, a detailed description of the structure of the key switch 100 has been omitted. In implementations, various key switches using magnets may realized using one or more of the above-described embodiments of the present invention. FIG. 42 illustrates how to fix an upper magnet 130 to a key top 110 or 1 10'. Referring to FIG. 42, the upper magnet 130 is inserted into a key shaft 120 of a key-top unit 100 or 100', but may not be able to be firmly fixed to the key top 1 10 or 1 10', whereas a lower magnet 360 is firmly fixed onto a membrane film 320 of a base unit 300 or 300' by a coating layer 380. Therefore, in order to prevent the upper magnet 130 from being moving vertically inside the key shaft 120, a supporting column 122 may be provided inside the key shaft 120. In addition, a groove 125 may be formed along the inner circumference of the key shaft 120, and a pawl 135 which can engage with the groove 125 may be formed along the outer circumference of the upper magnet 130. The pawl 135 may be hemispherical, but the present invention is not restricted to this. The pawl 135 may be formed in various shapes, other than a hemispherical shape.

[industrial Applicability]

As described above, according to the present invention, it is possible to reduce the probability of abrasion and breakdown of key switches caused by repeated keystrokes by using the repulsive force between magnets. Thus, it is possible to prolong the lifetime of key switches.

In addition, according to the present invention, it is possible to reduce the size of keyboards. Conventionally, key switches are required to have a predetermined height in order to generate repulsive force. However, according to the present invention, it is possible to reduce the height of key switches using the repulsive force between magnets. Therefore, it is possible to provide slim keyboards that are capable of minimizing the degree to which the wrists must be bent to use a keyboard, and are thus suitable for prolonged typing tasks. Moreover, given that magnets are known to stimulate the human metabolism, the key switch according to the present invention is expected to stimulate the human metabolism using magnets included therein.

Furthermore, according to the present invention, it is possible to easily adjust the repulsive force of each key switch by adjusting the degree of magnetization, given that a key switch is driven by the repulsive force between magnets and that the repulsive force between the magnets is determined by the degree of magnetization of the magnets. In addition, it is possible to vary the amount of pressure required to activate a key switch according to which finger is supposed to hit the key switch.

The present invention can be effectively applied to various types of key switches that are designed to be pressed and that enable keystrokes using repulsive force.

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 spirit and scope of the present invention as defined by the following claims.

Claims

1. A key switch using magnets, the key switch comprising: a base unit on which a number of contact terminal units are disposed, the contact terminal units generating an electrical signal by coming in contact with each other; and a key-top unit which receives a keystroke and moves vertically, wherein the key-top unit comprises an upper magnet which is attached to a bottom of the key-top unit, wherein the base unit comprises a lower membrane film on which a lower contact point is disposed, an upper membrane film on which an upper contact point that can be placed in contact with the lower contact point is disposed and which is disposed above the lower membrane film, a spacer film which is interposed between the lower membrane film and the upper membrane film and includes a hole through which the upper contact point and the lower contact point can be placed in contact with each other, and a lower magnet which is fixed onto the upper membrane film and faces the upper magnet, and wherein the upper magnet and the lower magnet provide repulsive force to the key-top unit and the base unit.

2. The key switch of claim 1, further comprising a vinyl coating layer which is disposed on the lower magnet so that the lower magnet can be fixed.

3. The key switch of claim 1, further comprising a key frame unit which is disposed on the base unit and comprises an inner wall that guides the vertical movement of the key-top unit.

4. The key switch of claim 3, further comprising a click- feel generation unit which is disposed in the key frame unit, comprises an elastic metal stick that is bent twice, and provides a click feel to a user when the key-top unit is lowered by more than a predetermined distance and is thus placed in contact with the click-feel generation unit.

5. The key switch of claim 3, further comprising a stem unit, which is disposed between the inner wall of the key frame unit and the key-top unit that moves vertically within the inner wall of the key frame unit, is coupled to the key-top unit and moves vertically along with the key-top unit.

6. The key switch of claim 5, wherein the stem unit is formed of polyacetal (POM).

7. The key switch of claim 1, further comprising a link unit which comprises two links that are coupled to the key-top unit and the base unit so as to be able to rotate.

8. The key switch of claim 1, wherein repulsive force of the key switch is varied according to which finger is supposed to hit the key switch.

9. The key switch of claim 2, wherein repulsive force of the key switch is varied according to the thickness of the vinyl coating layer and according to which finger is supposed to press the key switch.

10. The key switch of claim 8, wherein the repulsive force of the key switch is varied using a magnet holder in which the upper magnet is contained.

11. The key switch of claim 8, wherein the repulsive force of the key switch is varied according to the size of the upper magnet in the magnet holder.

12. The key switch of claim 1, further comprising a contact protrusion which is disposed beneath the upper magnet and places the upper contact point in contact with the lower contact point by pressing the upper contact point when the key-top unit is lowered by more than a predetermined distance.

13. The key switch of claim 1, further comprising a contact protrusion plate which is disposed on the upper membrane film, comprises a protrusion for each key switch, and places the upper contact point in contact with the lower contact point by pressing the upper contact point when the key-top unit is lowered by more than a predetermined distance.

14. A key switch using magnets, the key switch comprising: a base unit on which a switch unit is disposed, the switch unit comprising a first electrode and a second electrode that generate an electrical signal when connected to each other ; and a key-top unit which receives a keystroke and moves vertically, wherein the key-top unit comprises an upper magnet which is attached to a bottom of the key-top unit, wherein the base unit comprises a membrane film on which the first and second electrodes are disposed, a lower magnet which is disposed beneath the membrane film and faces the upper magnet, and a coating layer which fixes the lower magnet, and wherein the upper magnet and the lower magnet provide repulsive force to the key-top unit and the base unit.

15. The key switch of claim 14, further comprising a key frame unit which is disposed on the base unit and comprises an inner wall that guides the vertical movement of the key-top unit.

16. The key switch of claim 15, further comprising a click-feel generation unit which is disposed in the key frame unit, comprises an elastic metal stick that is bent twice, and provides a click-feel to a user when the key-top unit is lowered by more than a predetermined distance and is thus placed in contact with the click-feel generation unit.

17. The key switch of claim 15, further comprising a stem unit, which is disposed between the inner wall of the key frame unit and the key-top unit that is vertical moved within the inner wall of the key frame unit, is coupled to the key-top unit and moves vertically along with the key-top unit.

18. The key switch of claim 17, wherein the stem unit is formed of polyacetal (POM).

19. The key switch of claim 14, further comprising a link unit which comprises two links that are coupled to the key-top unit and the base unit so as to be able to rotate.

20. The key switch of claim 14, wherein repulsive force of the key switch is varied according to which finger is supposed to press the key switch.

21. The key switch of claim 20, wherein repulsive force of the key switch is varied according to the thickness of the coating layer.

22. The key switch of claim 20, wherein the repulsive force of the key switch is varied using a magnet holder in which the upper magnet is contained.

23. The key switch of claim 22, wherein the repulsive force of the key switch is varied according to the size of the upper magnet in the magnet holder.

24. The key switch of claim 23, wherein the magnet holder is formed of a conductive material selected from copper, a copper alloy, aluminum, an aluminum alloy, steel, stainless steel, and a combination thereof.