GB2107933A - Key board unit - Google Patents
Key board unit Download PDFInfo
- Publication number
- GB2107933A GB2107933A GB08228733A GB8228733A GB2107933A GB 2107933 A GB2107933 A GB 2107933A GB 08228733 A GB08228733 A GB 08228733A GB 8228733 A GB8228733 A GB 8228733A GB 2107933 A GB2107933 A GB 2107933A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sheet member
- covering sheet
- circuit board
- protrusions
- contact points
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
- H01H13/70—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard
- H01H13/78—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard characterised by the contacts or the contact sites
- H01H13/785—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard characterised by the contacts or the contact sites characterised by the material of the contacts, e.g. conductive polymers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
- H01H13/70—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard
- H01H13/702—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
- H01H13/70—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard
- H01H13/702—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
- H01H13/703—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches characterised by spacers between contact carrying layers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2201/00—Contacts
- H01H2201/022—Material
- H01H2201/026—Material non precious
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2201/00—Contacts
- H01H2201/022—Material
- H01H2201/032—Conductive polymer; Rubber
- H01H2201/034—Conductive polymer; Rubber anisotropic; Zebra
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2203/00—Form of contacts
- H01H2203/012—Microprotrusions
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2203/00—Form of contacts
- H01H2203/016—Form of contacts universal; modular
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2203/00—Form of contacts
- H01H2203/024—Convex contact surface
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2211/00—Spacers
- H01H2211/006—Individual areas
- H01H2211/014—Individual areas universal
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2227/00—Dimensions; Characteristics
- H01H2227/024—Spacer elements
Abstract
A keyboard for use, for example, in microprocessors or word processors comprises a printed circuit board 1 provided with sets of fixed contacts and a flexible sheet 2 laid over and assembled with the board 1. The flexible sheet 2 has uniformly distributed electroconductive strip or island areas forming movable contacts 2a at positions facing the sets of the fixed contacts so that one or more of the conductive areas, but not one specific area, lies just above each set of the fixed contacts and serves as the movable contact. In this way exact positioning of the flexible sheet 2 on to the circuit board 1 is not necessary. The circuit board 1 and/or the flexible sheet 2 are provided with dot or pimple-like, or strip-like or line protrusions 3a of insulating resilient material to hold the electroconductive areas clear of the fixed contacts except when the flexible sheet 2 is pressed at a key position above a set of fixed contacts. The protrusions 3a are located between the sets of fixed contacts and between the electroconductive areas 2a. <IMAGE>
Description
SPECIFICATION
Key board unit
The present invention relates to key board units suitable for use, for example, in multi-term input pieces of apparatus, word processors, microprocessors and like apparatus.
Conventional key board units, which are widely used in the above mentioned apparatus usually comprise a printed circuit board which is made of an electrically insulating, relatively rigid material and is provided on its upper surface with a plurality of pairs or other sets of fixed contact points formed by printing or other suitable methods, and an insulating flexible and resilient covering sheet member which is laid over the printed circuit board and bears a plurality of movable contact points on its surface which faces the printed circuit board. A suitable space to provide a key stroke is provided by a sheet-like electrically insulating spacer between the circuit board and the covering sheet member in such a manner that each of the movable contact points faces one of the sets of the fixed contact points.
When the covering sheet member is pushed at a position just above one of the movable contact points by pressing a key top member thereon with a finger or a flexible display sheet laid on the covering sheet member is pushed with a pen-like pointer, the movable contact point is depressed towards the fixed contact points on the printed circuit board and finally contacts them to close an electric circuit therebetween.
When the key board unit contains a great number of input terms, such as the input apparatus for Chinese characters which may have several thousands input terms, it is very essential that the spacing or pitch of the arrangement of the keys should be small enough to ensure that all of the input terms are within the reach of the operator or the key board unit is not so large as to become very cumbersome. Such a key board unit with a fine pitch in the key arrangement raises difficulties in the fabrication thereof since extremely high accuracy is required in the precise positioning of the covering sheet member and the printed circuit board as well as the display sheet or key tops on the covering sheet member to ensure reliable contacting between the movable contact points and the sets of fixed contact points.In addition, failure or strain of only one of the large number of the keys may make the entire key board unit unacceptable in a finished apparatus so that handling of such a key board unit requires a great deal of care. Furthermore, in a key board unit which is operated by pushing the key position with a pen-like pointer, the insulating spacer for forming the key stroke between the movable and fixed contact points must be as thin as possible, for example 0.1 mm or smaller in thickness to ensure reliable contacting of the contact points so that such a key board unit is unavoidably subject to the disadvantages of accidental or inadvertent closure or short circuiting of the contact points caused by the influence of temperature change or vibration and mechanical shocks.
It is an object of the present invention to provide an improved key board unit which is free from the above described disadvantages and difficulties in the prior art key board units of the above mentioned type.
To this end, according to this invention, a key board unit comprises:- (a) a printed circuit board made of an electrically insulating material and provided with a plurality of sets of fixed contact points on one surface thereof, and
(b) a flexible and resilient covering sheet member which is laid over the printed circuit board and is made of an electrically insulating material, the covering sheet member being provided with a multiplicity of substantially uniformly distributed strip-like or island-like electroconductive areas on its surface which face the printed circuit board;;
either the printed circuit board or the covering sheet member being provided on their facing surfaces with a plurality of substantially uniformly distributed pimple-like or dot protrusions, or striplike or line protrusions made of an electrically insulating, resilient material, the printed circuit board and the covering sheet member being assembled together with the protrusions intervening between them and the protrusions being located between the sets of fixed contact points and between the electroconductive areas, so that when the surface of the covering sheet member is pressed at a key position above a set of fixed contact points at least one of the eiectroconductive areas is moved into contact with the fixed contact points to establish a circuit between them.
Some examples of keyboard units in accordance with the invention will now be described with reference to the accompanying drawings in which: Figures 1 a to 1 C are cross sectional views of three examples of keyboard units in accordance with the invention:
Figures 2 and 3 are perspective views of examples of covering sheet members forming part of the keyboard units in accordance with the invention, the members being provided with striplike and island-like electroconductive areas, respectively, and strip-like protrusions and pimplelike protrusions, respectively on one surface thereof; and
Figures 4a to 4e are views of the pattern of island-like electroconductive areas provided on the surfaces of examples of the covering sheet members of key board units in accordance with the invention.
All of the examples of the key board unit of the present invention basically have a two-layer structure as shown in Figures 1 a to 1 C composed of a printed circuit board 1 and a flexible and resilient covering sheet member 2. The covering sheet member 2 is provided on the surface facing the printed circuit board 1 with a plurality of striplike or stripe-wise, or island-like electroconductive areas so that, when the covering sheet member 2 is pushed at a key position with a finger or a penlike pointer, the covering sheet member 2 is depressed at the position and brought into contact with the printed circuit board 1 thereby closing the circuit between a set of fixed contact points on the printed circuit board with one of the electroconductive areas on the covering sheet member 2.When the above pushing force is removed, the covering sheet member 2 regains its undepressed form so that the electric circuit closed between the fixed contact points is opened.
The above mentioned key operation is ensured by providing a suitable space for key stroke between the printed circuit board 1 and the covering sheet member 2 and, in the inventive key board unit, such a space for key stroke is provided by the dot protrusions or line protrusions 3a, 3b formed of an electrically insulating flexible material on the surface of either the printed circuit board 1 or the covering sheet member 2 facing the other or the surfaces of both of them.
It is of course optional that a spacer sheet may be inserted between the printed circuit board 1 and the covering sheet member 2 as in the conventional key board units. Further, the covering sheet member 2 is overlaid, as is shown in
FIGURES 1 a to 1 c, with a display sheet 4 indicating the appropriate key positions or a number of key top members are mounted on the covering sheet member 2 together with an upperboard as in a relatively large key board unit of the prior art.
Characteristically and different from conventional key board units, the inventive key board unit has no definitely positioned movable contact points on the inside surface of the covering sheet member 2 each corresponding one-to-one to each set of the fixed contact points on the printed circuit board 1 but the role of the movable contact points is played by one or more of the stripe-wise or island-wise electroconductive areas formed on the surface of the covering sheet member 2 facing the printed circuit board 1.In this connection, the stripe-wise or island-wise electroconductive areas are distributed substantially uniformly all over the surface of the covering sheet member 2 at least in the region under which the sets of the fixed contact points are provided on the printed circuit board 1 so that one or more of the electroconductive areas eventually coming just above the set of the fixed contact points can work as the movable contact points. Accordingly, there can be obtained a great advantage in the improved efficiency of the fabrication of the key board unit not only in the simplified process for the preparation of the covering sheet member 2 but also in the easiness in the mounting of the covering sheet member 2 on the printed circuit board 1 due to the absence of the necessity of exact positioning between the movable and fixed contact points.
The printed circuit board 1 as a part of the inventive key board unit is not particularly limitative in the structure thereof or rather conventional as being made of a rigid or somewhat flexible, electrically insulating plate provided on one surface with a plural number of sets of fixed contact points and circuit pattern for wiring according to the design of the key board unit.
On the other hand, the covering sheet member 2 is unique in the invention being characteristically different from conventional ones, as is mentioned above, by the absence of the definitely positioned movable contact points and by the presence of the stripe-wise or island-wise electroconductive areas in place thereof provided on the surface facing the printed circuit board 1 so that one or more of the electroconductive areas eventually coming just above the fixed contact points act as the movable cqntact point. Therefore, the above mentioned stripe-wise or island-wise electroconductive areas should be distributed substantially uniformly all over the region in which the printed circuit board 1 is provided with sets of the fixed contact points so that any one of the sets of the fixed contact points has at least one electroconductive area thereabove on the covering sheet member 2.In this type of the combination of the fixed contact points and the movable contact points, exact positioning of the printed circuit board 1 and the covering sheet member 2 is no longer necessary so that the key board unit is manufactured with very much improved working efficiency.
The covering sheet member 2 is made of an electrically insulating sheet-like flexible material provided on the inside surface, i.e. the surface facing the circuit board 1, with stripe-wise or island-wise electroconductive areas. Such conductive areas are formed, for example, by printing with an electroconductive paint or ink or with foils of a metal such as copper and aluminum forming a conductive layer by a known technique such as photoetching. The thickness of such a conductive layer forming the electroconductive areas is not limitative and the surface of the layer may be raised slightly above or recessed from the surface level of the covering sheet member 2 per se. It is preferable that the surface of the conductive layer forming the stripe-wise or islandwise electroconductive areas is roughened or sanded to ensure reliableness of contacting with the fixed contact points. Further, the surface of the conductive layer may be convexed toward the fixed contact points. The distribution of the conductive areas should be sufficiently dense so that a set of the fixed contact points on the circuit board 1 is always contacted with at least one of the conductive areas positioned thereabove to close the electric circuit when the covering sheet member 2 is depressed at the key position.
In addition to the above mentioned requirement of the substantially uniform and sufficiently dense distribution of the conductive areas, each of the electroconductive areas should have a dimension sufficiently large to bridge the set of the fixed contact points on the circuit board 1 but not excessively large in order to avoid inadvertent short-circuiting between two sets of the fixed
contact points on the circuit board 1.
The stripe-wise or island-wise
electroconductive areas on the surface of the
covering sheet member 2 are not necessarily
formed of the surface layer thereon with
conductive paint, ink or metal foil bonded thereto
but the covering sheet member 2 per se has a
composite structure composed of the insulating
portions and conductive portions distributed in the former in a stripe-wise or island-wise manner. For example, the covering sheet member 2 illustrated in FIGURE 2 is prepared by slicing an alternately stratified block of conductive rubber sheets 2a and insulating rubber sheets 2b in a plane perpendicular to the direction of stratification so that the resultant rubber sheet 2 has a striped appearance as is shown in FIGURE 2 and each of the conductive stripes 2a has a depth equal to the thickness of the sheet 2.The covering sheet member 2 shown in FIGURE 3 is formed by providing the electroconductive areas 2a by, for example, printing with a conductive paint in an island-wise manner on the surface of an insulating rubber sheet 2b.
FIGURES 4a to 4e each illustrate a pattern of the electroconductive areas 2a on the surface of the covering sheet member 2 similar to that shown in FIGURE 3 formed by a suitable method such as etching, printing, transferring, stratification and the like. Needless to say, the areas 2b not covered by the conductive areas 2a are insulating with the surface of the insulating sheet exposed bare.
It may be too much to say that the stripe-wise or island-wise electroconductive areas 2a may not be provided all over the surface of the covering sheet member 2 but may be limited on the portions just above the areas of the printed circuit board 1 where the fixed contact points are provided. It is also optional that the stripe-wise or island-wise conductive areas 2a are divided into several regions or groups and each of the regions is provided with different pattern of the conductive areas according to the condition of the fixed contact points therebelow so that the versatility in the design of the key board unit is greatly increased to cover any types and sizes of the fixed contact points on the printed circuit board 1.
The width of each of the conductive stripes 2a as well as the pitch of the stripes in the covering sheet member 2 illustrated in FIGURE 2 and the shape, size and distribution density of the islandwise conductive areas 2a in the covering sheet member 2 illustrated in FIGURE 3 should be determined in consideration of the size and shape of the fixed contact points on the printed circuit board 1 and the distance between the fixed contact points to be short-circuited by being contacted with one or more of the conductive areas 2a on the covering sheet member 2 working as a movable contact point.When the conductive areas 2a are island-wise, in particular, each of the areas 2a must be sufficiently large to bridge two fixed contact points so as to close the electric circuit therebetween and should be larger than the
distance between the fixed contact points on the
printed circuit board 1 as a matter of course. The
choice of the stripe-wise or the island-wise
conductive areas 2a on the covering sheet
member 2 depends on the distribution of the fixed contact points on the circuit board 1.Generally speaking, it is preferable that the conductive areas 2a on the covering sheet member 2 are stripewise when the fixed contact points on the circuit board 1 are formed of a set of parallel electrodes and the stripe-wise conductive areas 2a on the covering sheet member 2 run in the direction approximately perpendicular to the direction of the parallel electrodes as the fixed contact points on the circuit board 1. On the other hand, island-wise conductive areas 2a on the covering sheet member 2 are preferred when the fixed contact points on the circuit board 1 are formed of electrodes each in a comb-like configuration or crescent-like form facing one another.
Further characteristically, the inventive key board unit is provided with a plurality of dot protrusions or line protrusions 3 between the printed circuit board 1 and the covering sheet member 2 made of an electrically insulating, flexible material such as a rubber. The protrusions 3 should be integrally provided on either the printed circuit board 1 or the covering sheet member 2 as is shown in FIGURES 1 a to 1 c, in which the covering sheet member 2 in FIGURE 1 a is provided with such protrusions 3a on the surface facing the circuit board 1 while the circuit board 1 in FIGURE 1 b is provided with such protrusions 3b.It is optional that both of the covering sheet member 2 and the circuit board 1 are provided with such protrusions 3a or 3b, respectively, as is shown in FIGURE Ic although it is a convenient and preferable way that the protrusions 3 are provided on the covering sheet member 2 alone. The protrusions 3a, 3b serve as the spacer means to form a space for key stroke between the covering sheet member 2 and the printed circuit board 1.
As is mentioned above, the protrusions 3a, 3b are formed of an electrically insulating, rubbery elastic material of which the hardness is preferably 80 or below by the scale of rubber hardness specified in JIS K6301. Alternatively, the material for the protrusions may be a cellular foamed body of a rubber comprising a closed- or open-cell structure. Each of the dot protrusions may have a form of a stud, pointed or truncated cone, semisphere or the like form wit,hout particular limitations and the line protrusions each may have a cross section of a rectangular, trapezoidal, semicircular or the like form also without particular limitations.
The height of the protrusions 3a, 3b above the surface of the covering sheet member 2 or printed circuit board 1 is preferably in the range from 0.12 to 1 mm and the diameter of a dot protrusion or width of a line protrusion is preferably 2 mm or smaller. Adjacently positioned dot protrusions or line protrusions should be separated by a distance of 0.05 to 5 mm. The above mentioned parameters should carefully be determined in order to ensure that pushing of the covering sheet member 2 at the key position with a finger tip or with a pen-like pointer reliably brings the conductive area 2a on the other surface of the covering sheet member 2 into contact with the fixed contact points on the circuit board 1 by being not disturbed by the protrusions laterally deformed and bulged out as a result of pushing eventually to be in contact with each other.
The above limitation in the height of the protrusions 3a or 3b in the range from 0.12 to 1 mm is given because a height smaller than 0.12 mm cannot give a sufficiently wide space for key stroke so that the key board unit is subject to a drawback due to the dew condensation between the circuit board 1 and the covering sheet member 2 by the changes in the ambient temperature and humidity while a height of the protrusions 3a or 3b larger than 1 mm is detrimental to the reliable performance of the key board unit because the protrusions 3a or 3b must be excessively deformed and bulged out by pushing to prevent contacting between the fixed contact points on the circuit board 1 and the conductive areas 2a on the covering sheet member 2 working as the movable contact point.
The distance between adjacent protrusions 3a or 3b should be determined within the limits of 0.05 and 5 mm because the contacting of the conductive areas 2a on the covering sheet member 2 as the movable contact point with the fixed contact points on the circuit board 1 is unduly disturbed by pushing at the key position with a finger tip or a pen-like pointer when the protrusions 3a or 3b are provided at the positions too close to each other while an excessively large distance between the adjacent protrusions 3a or 3b over 5 mm may result in untimely shortcircuiting between the fixed contact points by the eventual slackening of the covering sheet member
2 when subjected to vibration or mechanical
shocks.It is of course that the distribution of the
protrusions 3a or 3b may not be uniform
throughout but may be modified from portion to
portion according to the pattern of the
electroconductive areas 2a on the covering sheet
member 2 and/or the condition or arrangement of
the fixed contact points on the printed circuit
board 1.
The key board unit of the invention is advantageous in the versatility of the key board design so that, for example, the key board unit can
be designed so as not to be operated by a finger tip but operated only by a pen-like pointer having
a specified small tip. Therefore, a key board unit
having a high density of key unit arrangement can
readily be obtained according to the invention.
FIGURE 2 is a perspective view of a covering
sheet member 2 composed of the alternate stripes
of the electroconductive areas 2a and the
insulating areas 2b and provided with the line
protrusions 3a on the surface to face the circuit
board 1 when the covering sheet member 2 is put
on the circuit board 1. It is preferable that the running directions of the stripe-wise electroconductive areas 2a and the insulating line protrusions 3a are perpendicular to each other.
FIGURE 3 illustrate a perspective view of another covering sheet member 2 composed of the conductive areas 2a running in one direction to give a streaking appearance and the matrix of the insulating areas 2b and provided with several stud-like insulating protrusions 3a. It is also essential that each of the dot or line protrusions 3a on the covering sheet member 2 is not so large that one of the fixed contact points on the circuit board 1 may be entirely covered by the protrusion eventually coming thereon when the covering sheet member 2 is depressed by pushing at a key position.
FIGURES 4a to 4e each illustrate an example of the patterns of the island-wise electroconductive areas 2a on the inside surface of the covering sheet member 2. It is noted that the pattern and distribution of the above mentioned dot protrusions 3a or 3b also may be similar to these patterns for the electroconductive areas 2a.
The manner in which the above mentioned dot protrusions or line protrusions 3a or 3b are provided on the surface of the printed circuit board 1 and/or the inside surface of the covering sheet member 2 is not particularly limitative and they can readily be formed by a known method such as printing, transferring and the like.
The key board unit of the present invention is obtained in the following manner. That is, a printed circuit board 1 provided with sets of the fixed contact points and circuit pattern for wiring on the surface and a covering sheet member 2 of an insulating elastic material provided with the electroconductive areas 2a on one surface are prepared. Further, the dot protrusions or line protrusions 3a and/or 3b are formed on the surface of the printed circuit board 1 and/or the surface of the covering sheet member 2 with an insulating elastic material and the covering sheet
member 2 is laid on the printed circuit board 1 with the protrusions 3a or 3b therebetween and
integrated together. It is optional to insert a sheet
like insulating spacer having a plurality of openings at the positions corresponding to the sets of fixed contact points on the printed circuit
board 1 therebetween. It is a matter of design of the key board unit whether a plurality of key tops are mounted at the key positions on the covering sheet member 2, if necessary, in combination with
an upper-board or the covering sheet member 2 is overlaid with a display sheet 4 provided with
indicative markings thereon for the key positions
as is illustrated in FIGURES 1 a to 1 c. It is of course
optional that the covering sheet member 2 itself is
provided with the indicative markings for the key
positions by direct printing or any other suitable
means.
In the manufacturing of the inventive key board unit, exact positioning of the covering sheet member 2 on to the printed circuit board 1 is entirely unnecessary because the covering sheet member 2 is not provided with movable contact points at definite positions but either one or more of the electroconductive areas 2a on the covering sheet member 2 eventually coming just above the respective set of the fixed contact points serve as the movable contact point.It is of course, however, that, when the covering sheet member 2 itself is provided with the indicative markings for the key positions on the upper surface, each of the markings should be positioned approximately above the respective set of the fixed contact points on the printed circuit board 1 although it is a relatively easy matter to satisfy such a requirement in comparison with the exact positioning of the movable contact points on the fixed contact points in the conventional key board units. Furthermore, the surface of the printed circuit board 1 and/or the covering sheet member 2 is protected by a number of the dot or line protrusions 3a and/or 3b so that any inadvertent damages or stains to these surfaces can be effectively avoided in the course of manufacturing of the key board unit greatly contributing to the improvement in the yield of acceptable products in the manufacture of key board units.
Claims (6)
1. A key board unit which comprises:- (a) a printed circuit board made of an electrically insulating material and provided with a pluralityof sets of fixed contact points on one surface thereof, and
(b) a flexible and resilient covering sheet
member which is laid over the printed circuit
board and is made of an electrically insulating
material, the covering sheet member being
provided with a multiplicity of substantially
uniformly distributed strip-like or island-like
electroconductive areas on its surface which faces
the printed circuit board;;
either the printed circuit board or the covering
sheet member being provided on their facing
surfaces with a plurality of substantially uniformly
distributed pimple-like or dot protrusions, or strip
like or line protrusions made of an electrically
insulating, resilient material, the printed circuit board and the covering sheet member being assembled together with the protrusions intervening between them and the protrusions being located between the sets of fixed contact points and between the electroconductive areas, so that when the surface of the covering sheet member is pressed at a key position above a set of fixed contact points at least one of the electroconductive areas is moved into contact with the fixed contact points to establish a circuit between them.
2. A key board unit according to Claim 1, in which the electroconductive areas on the covering sheet member have a size and density of distribution such that each of the sets of the fixed contact points on the circuit board is contacted by at least one of the electroconductive areas when the member is pressed above the set of contacts.
3. A key board unit according to Claim 1 or
Claim 2, in which the protrusions each have an area, thickness and hardness capable of ensuring electric insulation between the circuit board and the covering sheet member when the covering sheet member is compressed but the protrusions being such that they do not interfere with the establishment of contact between at least one of the electroconductive areas on the covering sheet member and the sets of fixed contact points on the circuit board when the covering sheet member is pressed at a key position.
4. A key board unit according to any one of
Claims 1 to 3, in which the protrusions are provided on the covering sheet member.
5. A key board unit according to Claim 4, in which the covering sheet member is provided with parallel strip-like electroconductive areas and strip-like or line protrusions which extend in a direction perpendicular to the longitudinal direction of the strip-like electroconductive areas.
6. A keyboard unit according to Claim 1, constructed substantially as described with reference to any one of Figures 1 a to 1 c, and any one of Figures 2 to 4e of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56165530A JPS5866216A (en) | 1981-10-16 | 1981-10-16 | Keyboard unit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2107933A true GB2107933A (en) | 1983-05-05 |
| GB2107933B GB2107933B (en) | 1985-07-24 |
Family
ID=15814137
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08228733A Expired GB2107933B (en) | 1981-10-16 | 1982-10-07 | Key board unit |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5866216A (en) |
| GB (1) | GB2107933B (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2562319A1 (en) * | 1984-03-28 | 1985-10-04 | Mektron France Sa | MEMBRANE SWITCH |
| GB2166295A (en) * | 1984-10-01 | 1986-04-30 | Karl Michael Hargreaves | Flexible electric switch |
| WO1986005317A1 (en) * | 1985-03-06 | 1986-09-12 | Mayser-Gmbh & Co. | Switching mat and process for its manufacture |
| EP0240192A2 (en) * | 1986-03-15 | 1987-10-07 | Chrome Print limited | Membrane switch |
| GB2222485A (en) * | 1988-09-01 | 1990-03-07 | Kokoku Rubber Tech | Pressure-sensing electric conductor and its manufacturing method |
| FR2643754A1 (en) * | 1989-02-28 | 1990-08-31 | Thomson Brandt Armements | PROCESS FOR MAKING A FLAT CONNECTION |
| US5028752A (en) * | 1988-04-28 | 1991-07-02 | Mitsubishi Denki Kabushiki Kaisha | Push button device |
| WO1999027550A1 (en) * | 1997-11-26 | 1999-06-03 | Burgess Lester E | Pressure activated switching device |
| EP1156643A2 (en) * | 2000-05-16 | 2001-11-21 | SAMSUNG ELECTRONICS Co. Ltd. | Step keys, step key assembly, and terminal having the step key assembly |
| EP2037474A1 (en) | 2007-09-13 | 2009-03-18 | SCHURTER GmbH | Electrical button |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58154528U (en) * | 1982-04-09 | 1983-10-15 | アルプス電気株式会社 | keyboard switch |
| JPS6166831U (en) * | 1984-10-09 | 1986-05-08 |
-
1981
- 1981-10-16 JP JP56165530A patent/JPS5866216A/en active Pending
-
1982
- 1982-10-07 GB GB08228733A patent/GB2107933B/en not_active Expired
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2562319A1 (en) * | 1984-03-28 | 1985-10-04 | Mektron France Sa | MEMBRANE SWITCH |
| GB2166295A (en) * | 1984-10-01 | 1986-04-30 | Karl Michael Hargreaves | Flexible electric switch |
| WO1986005317A1 (en) * | 1985-03-06 | 1986-09-12 | Mayser-Gmbh & Co. | Switching mat and process for its manufacture |
| US4773155A (en) * | 1985-03-06 | 1988-09-27 | Mayser Gmbh & Co. | Mat switch and process for its manufacture |
| EP0240192A2 (en) * | 1986-03-15 | 1987-10-07 | Chrome Print limited | Membrane switch |
| EP0240192A3 (en) * | 1986-03-15 | 1988-10-26 | Chrome Print limited | Membrane switch |
| US5028752A (en) * | 1988-04-28 | 1991-07-02 | Mitsubishi Denki Kabushiki Kaisha | Push button device |
| GB2222485A (en) * | 1988-09-01 | 1990-03-07 | Kokoku Rubber Tech | Pressure-sensing electric conductor and its manufacturing method |
| GB2222485B (en) * | 1988-09-01 | 1993-04-21 | Kokoku Rubber Tech | Pressure-sensitive electrical conductor and method of manufacturing the same |
| WO1990010320A1 (en) * | 1989-02-28 | 1990-09-07 | Thomson-Brandt Armements | Process for producing a flat connection |
| FR2643754A1 (en) * | 1989-02-28 | 1990-08-31 | Thomson Brandt Armements | PROCESS FOR MAKING A FLAT CONNECTION |
| US6114645A (en) * | 1995-04-27 | 2000-09-05 | Burgess; Lester E. | Pressure activated switching device |
| WO1999027550A1 (en) * | 1997-11-26 | 1999-06-03 | Burgess Lester E | Pressure activated switching device |
| EP1156643A2 (en) * | 2000-05-16 | 2001-11-21 | SAMSUNG ELECTRONICS Co. Ltd. | Step keys, step key assembly, and terminal having the step key assembly |
| EP1156643A3 (en) * | 2000-05-16 | 2004-04-14 | SAMSUNG ELECTRONICS Co. Ltd. | Step keys, step key assembly, and terminal having the step key assembly |
| EP2037474A1 (en) | 2007-09-13 | 2009-03-18 | SCHURTER GmbH | Electrical button |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5866216A (en) | 1983-04-20 |
| GB2107933B (en) | 1985-07-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19971007 |