Input device

An input device has a circular arc resistive layer and a metal plate as a conductive layer that is faced to the circular arc resistive layer, and can detect a position operated by partial contact between them. The input device has an element unit where a linear insulating layer as a contact preventing unit for preventing both ends of the circular arc resistive layer from simultaneously coming into contact with the metal plate during operation is disposed on one end of the circular arc resistive layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an input device constituting an operation unit of various electronic apparatuses.

2. Background Art

Recently, various electronic apparatuses have been miniaturized and lightened in weight. The number of electronic apparatuses operated by selecting a predetermined function by moving a cursor displayed on a screen have been increased. A conventional input device corresponding to the operation form of the various electronic apparatuses is described hereinafter with reference to the drawings.

FIG. 9is a conceptual diagram of a conventional input device. InFIG. 9, element unit10of the conventional input device includes circular arc resistive layer1and a circular-ring-like conductive layer3facing circular arc resistive layer1at a predetermined distance. Each of ends1A and1B of circular arc resistive layer1and conductive layer3are coupled to control unit5. Circular arc resistive layer1, conductive layer3, and drawn parts from them are formed on resin films that are faced to each other, but are not shown.

As shown in a sectional view ofFIG. 10and an exploded perspective view ofFIG. 11, operation body15having a spherical lower end used as an operation surface is disposed tiltably on element unit10. Coil spring17is disposed in case19in order to support operation body15at a neutral position when operation body15is not operated.

Next, an operation of the conventional input device having the above-mentioned structure is described hereinafter. The conventional input device is operated by tilting operation body15. In other words, the upper film is partially deflected with a pressing force from its outside using operation body15, thereby providing a state where circular arc resistive layer1and conductive layer3partially come into contact with each other correspondingly to the deflected part. A predetermined voltage is placed between ends1A and1B of circular arc resistive layer1under control of control unit5. The electric potential at the contact position is therefore input into control unit5through the drawn part from conductive layer3. Control unit5specifies the operation position in response to a partial voltage ratio based on the input, and moves a cursor in response to the information.

Conventional art information related to the present invention is disclosed by Japanese Patent Unexamined Publication No. H11-232027, for example.

The structure of the conventional input device including its control method and its detection method of an operation position can be simplified, and especially element unit10can be thinned advantageously. However, the conventional input device has the following problem: when operation body15is tilted in an angle direction between ends1A and1B of circular arc resistive layer1, ends1A and1B simultaneously come into contact with conductive layer3to provide a substantial short-circuit state. In this state, the quantity of flowing current increases to hasten the battery consumption, the output of the partial voltage ratio is the same as the output at the diagonal position to disable determination of the operation position, disadvantageously.

The conventional input device is used for only four-way operation or the like in an attached state to an apparatus. However, input devices have been demanded to have high resolution with recent enhancement in function of the apparatus.

SUMMARY OF THE INVENTION

The present invention addresses the conventional problems, and provides an input device that has a circular arc resistive layer, has no failure during operation at an angle position between the ends of the circular arc resistive layer, can detect an operation position, and has high resolution.

The input device of the present invention has a conductive layer faced to the circular arc resistive layer, and can detect a position operated by partial contact between the circular arc resistive layer and the conductive layer. The input device has a contact preventing unit for preventing both ends of the circular arc resistive layer from simultaneously coming into contact with the conductive layer during operation at the angle position between the ends of the circular arc resistive layer.

Therefore, an input device can be achieved inexpensively where the operation-position detection state and power consumption state during operation between both ends of the circular arc resistive layer or at an angle position near each of the ends are equivalent to those at other angle positions, the operation position can be detected over the full circumference, and the resolution is high.

DETAILED DESCRIPTION OF THE INVENTION

Input devices of exemplary embodiments of the present invention will be described with reference to the drawings.

First Exemplary Embodiment

FIG. 1is an exploded perspective view of element unit40of an input device in accordance with exemplary embodiment 1 of the present invention.FIG. 2is a partial sectional view of element unit40of the input device that is taken in the broken line pointed by arrows2ofFIG. 1.FIG. 3is a conceptual diagram of the input device in accordance with exemplary embodiment 1.

InFIG. 1, element unit40of the input device has substrate20and metal plate31. Substrate20is a flexible resin film made of polyethylene terephthalate (PET) or the like, is formed in a shape having a tail part, and has circular arc resistive layer21printed on its lower face. Circular arc resistive layer21has a constant radial width. Ends21A and21B on both sides of circular arc resistive layer21are coupled to one-end sides of independent conductive first patterns22A and22B formed on the lower face of substrate20, respectively. The-other-end sides of first patterns22A and22B are coupled to electrode parts drawn to the tip of the tail part. Conductive second pattern35used for metal plate31is formed on the lower face of substrate20corresponding to the outer periphery of circular arc resistive layer21. The other end side of second pattern35, similarly to first patterns22A and22B, is coupled to an electrode part drawn to the tip of the tail part. The tip of the tail part of substrate20, including electrode parts, can be coupled to a corresponding connector.

Outer peripheral insulating layer41is made of insulating resin, and is formed so as to surround the outer periphery of circular arc resistive layer21at a predetermined distance. Outer peripheral insulating layer41covers first patterns22A and22B and second pattern35except for the electrode parts at the tip of the tail part and the electrode part coupled to one-end side of second pattern35.

Inner peripheral insulating layer42is made of insulating resin similarly to outer peripheral insulating layer41, and is formed inside circular arc resistive layer21at a predetermined distance.

Outer peripheral insulating layer41is coupled to inner peripheral insulating layer42through linear insulating layer44that has a narrow band shape and is formed in the radial direction. Linear insulating layer44is made of the same insulating resin as those of outer peripheral insulating layer41and inner peripheral insulating layer42. Outer peripheral insulating layer41, inner peripheral insulating layer42, and linear insulating layer44are formed on the lower face of substrate20by pattern printing. Of these insulating layers, preferably, at least outer peripheral insulating layer41and inner peripheral insulating layer42are simultaneously formed so as to have the same height.

Linear insulating layer44is formed in the radial direction of circular arc resistive layer21, and has a part laying on substrate20and a part lying on end21A on one side of circular arc resistive layer21. End21A on one side of circular arc resistive layer21is referred to one end21A, and end21B on the other side is referred to the other end21B.

In this structure, the part of linear insulating layer44formed so as to cover one end21A works as a contact preventing unit. Here, one end21A defines the opening in the circumferential direction of circular arc resistive layer21.

Metal plate31formed in a substantially circular shape similarly to the circular part having circular arc resistive layer21of substrate20is disposed under substrate20having circular arc resistive layer21or the like. Substrate20is stuck and held on metal plate31at positions of outer peripheral insulating layer41and inner peripheral insulating layer42via an adhesive (not shown). In other words, substrate20is arranged so that circular arc resistive layer21points downward and faces metal plate31working as a conductive layer.

In the held state, as shown inFIG. 2, the surface of the part of linear insulating layer44formed on one end21A of circular arc resistive layer21is in contact with the surface of metal plate31. The circular ring part formed of circular arc resistive layer21and the opening between both ends of circular arc resistive layer21thereof vertically faces the upper face of metal plate31at a predetermined distance over substantially full circumference except the circumferential width of linear insulating layer44on one end21A. Both circular arc resistive layer21and the part of linear insulating layer44may be vertically separated from metal plate31by a predetermined clearance.

While, the electrode part coupled to the one-end side of second pattern35exposed from outer peripheral insulating layer41is electrically coupled to coupling part31A of metal plate31via a conductive adhesive or the like

Element unit40of the input device is structured as discussed above, and a member for operation is disposed on element unit40. An example of the member for operation includes operation body50that has a substantially disk shape swelling in the central part of the upside thereof, as shown inFIG. 1. Operation body50has, on its flat lower face, operation projections51for pressing, from the upside of substrate20, the circular ring part formed of circular arc resistive layer21and the opening between the both ends of circular arc resistive layer21thereof. The shapes and arrangement states of operation body50and operation projection51are not especially limited. However, an input device including operation body50is hereinafter described as an example.

Operation projections51of operation body50are 10 cylindrical projections52independently arranged with 30° pitches and one circular arc projection53arranged at an angle position within the remaining 90°. The length of circular arc projection53is set so that each of the circumferential end positions thereof has an angle smaller than 30° with respect to cylindrical projection52adjacent to it.

The lower end of each cylindrical projection52has a flat small-diameter circular shape. The lower end of circular arc projection53has a circular arc shape that has the same width as the diameter of the small-diameter circular part and extends in the circumferential direction. The circular arc shape has both ends decreasing in height in the circumferential direction and has a large curvature radius. The bottoms of the small-diameter circular parts and the circular arc part define a predetermined curvature radius.

Operation body50disposed on substrate20is regulated by a case of an apparatus so that it does not rotate in a non-operation state, is held in a neutral state, and can be tilted downward by a pressing operation from its upside (not shown).

Operation body50is arranged so that circular arc projection53lies at a position over the opening between the both ends of circular arc resistive layer21. The opening angle between the both ends of circular arc resistive layer21is smaller than the angle formed by circular arc projection53. In the arrangement state of operation body50, the both ends of circular arc projection53are positioned over circular arc resistive layer21.

The input device of exemplary embodiment 1 has the above-mentioned structure. The input device is attached to a used apparatus by coupling first patterns22A and22B and second pattern35to control unit60of the apparatus by inserting the tail unit of substrate20into a connector attached to a wiring board (not shown) of the apparatus.FIG. 3is a conceptual diagram of the attached state.

An operation in the attached state is described hereinafter. Operation body50is pressed down from the outside to be tilted downward, substrate20is partially deflected downward by operation projection51corresponding to the operation position, the part of circular arc resistive layer21corresponding to the position is brought into contact with metal plate31. While, a predetermined voltage is applied to circular arc resistive layer21via first patterns22A and22B under control of control unit60. The electric potential at a time of the partial contact in the operation state is fed into control unit60via metal plate31and second pattern35. The partial voltage ratio of the predetermined voltage applied to circular arc resistive layer21can be determined based on the fed electric potential. Therefore, control unit60specifies the operation angle position based on the partial voltage ratio. In other words, the input device of the present invention has metal plate31as the conductive layer faced to circular arc resistive layer21, and can detect the position operated by the partial contact between circular arc resistive layer21and the conductive layer.

As discussed above, the input device of exemplary embodiment 1 has the following structure. Linear insulating layer44as the insulating layer used as a contact preventing unit is partially overlaid in the radial direction on one end21A of circular arc resistive layer21, and circular arc projection53is corresponded to the position over the opening between the both ends of circular arc resistive layer21. In other words, the input device of the present invention has a contact preventing unit for preventing the both ends of circular arc resistive layer21from simultaneously coming into contact with metal plate31as the conductive layer when operation is performed within the angle between the both ends of circular arc resistive layer21. Therefore, when operation body50is tilted in the angle direction between the both ends of circular arc resistive layer21, the both ends of circular arc resistive layer21are prevented from simultaneously coming into contact with metal plate31.

In other words, when operation body50is tilted in the angle direction between the both ends of circular arc resistive layer21, substrate20is pressed and partially deflected by circular arc projection53. This is similar to the cases at other angle positions. The part of linear insulating layer44overlaid on one end21A of circular arc resistive layer21is the greatest in height from substrate20. Therefore, operation body50is finely tilted to the circumferential side about the part of linear insulating layer44abutting on metal plate31from the abutting state. At this time, as shown inFIG. 4, linear insulating layer44and a part close to one end21A of circular arc resistive layer21come into contact with metal plate31, and the other end21B is kept separate from it. Alternatively, as shown inFIG. 5, linear insulating layer44and a part close to the other end21B come into contact with metal plate31, and one end21A is kept separate from it.

In either of these two cases, the electric potential at a time of the partial contact is fed into control unit60via metal plate31and second pattern35. Therefore, the operation position can be sufficiently detected. Also when operation body50is tilted in the angle direction close to each end of circular arc resistive layer21, a similar operation state is obtained. However, the detailed description is omitted.

In element unit40of the input device of embodiment 1, also when an operation is performed at an angle position between the both ends of circular arc resistive layer21or at an angle position close to each end, the both ends of circular arc resistive layer21are prevented from simultaneously coming into contact with metal plate31. Therefore, the simultaneous contact does not cause a problem, the operation position can be detected similarly to the other angle positions, and power consumption can be set similarly to those at the other angle positions.

Regarding the other angle positions, cylindrical projection52corresponding to the operation position of operation body50partially presses down substrate20. The part of circular arc resistive layer21at this position comes into contact with metal plate31. Thus, control unit60specifies the operation position.

Therefore, a total of 12 positions, namely 10 positions corresponding to the arrangement angle positions of cylindrical projections52and two positions corresponding to circular arc projection53, can be detected, and angle positions can be detected with substantially constant angle pitches.

Element unit40having linear insulating layer44as a contact preventing unit added to circular arc resistive layer21allows detection of operation positions in a high resolution over the full circumference of the circular ring part. Here, the circular ring part is formed of circular arc resistive layer21and the opening between its both ends. The resolution is set dependently on the arrangement state of the operation projections of operation body50, so that a desired resolution is obtained by appropriately setting the shape of operation body50. The arrangement restricting condition of element unit40is significantly relaxed when it is attached to an apparatus, differently from the conventional art. Therefore, the degree of freedom in design of the apparatus is also increased. Element unit40has a structure to which only linear insulating layer44is added, so that element unit40can be manufactured easily and inexpensively.

Linear insulating layer44is preferably formed on one end21A of circular arc resistive layer21so as to extend over the full width of circular arc resistive layer21in the radial direction. However, linear insulating layer44may be partially formed when the both ends of circular arc resistive layer21do not simultaneously become conductive.

The shape of operation body50may be set appropriately as discussed above. For example, the number of operation projections51and setting of arrangement positions thereof may be changed, operation projections with a continuous circular ring shape may be used, or the lower faces of them may be spherical as the conventional art.

Element unit40of the input device of embodiment 1 has linear insulating layer44overlaid on circular arc resistive layer21; however, an insulating layer as a contact preventing unit may be disposed on a facing position, which corresponds to one of the both ends of the circular arc resistive layer21, of the conductive layer. This structure can also prevent the both ends of circular arc resistive layer21from simultaneously coming into contact with metal plate31even when operation is performed at an angle position between the both ends of circular arc resistive layer21or an angle position close to each end.

Element unit40of this structure may be operated from the opposite side, namely, the conductive layer side may be arranged on the upside and operated from the upside by operation body50

Second Exemplary Embodiment

FIG. 6is an exploded perspective view of element unit70of an input device in accordance with exemplary embodiment 2 of the present invention.FIG. 7is a partial sectional view of element unit70of the input device that is taken in the broken line pointed by arrows7ofFIG. 6. Element unit70of the input device of exemplary embodiment 2 has an insulating film used as a contact preventing unit at a position different from that in exemplary embodiment 1. However, the other elements have much the same structure as that of exemplary embodiment 1, so that the same elements are denoted with the same reference marks and are not described in detailed.

Element unit70of the input device of embodiment 2 has the following structure shown inFIG. 6, similarly to element unit40of the input device of embodiment 1. Circular arc resistive layer21formed on the lower face of substrate20is vertically faced to metal plate31as a conductive layer at a predetermined distance. First patterns22A and22B, second pattern35, and the like are formed on the lower face of substrate20, and substrate20is stuck and held on metal plate31at positions of outer peripheral insulating layer41and inner peripheral insulating layer42on the outer and inner peripheries of circular arc resistive layer21, similarly to embodiment 1.

However, element unit70of the input device of embodiment 2 has no linear insulating layer44. As a contact preventing unit, island-like insulating layer75made of the insulating film is formed independently between both ends of circular arc resistive layer21on the lower face of substrate20. Island-like insulating layer75corresponds to the island unit. Island-like insulating layer75has much the same width as that of circular arc resistive layer21, and is formed in the circular ring part and at an intermediate position circumferentially at the same distance from the both ends of circular arc resistive layer21. Here, the circular ring part is formed of circular arc resistive layer21and the opening between the both ends thereof. As shown inFIG. 7, the circular ring part, including the formed place of island-like insulating layer75, is vertically faced to metal plate31over the full circumference at a predetermined distance.

Operation body50having operation projections51is arranged on substrate20disposed at an upward position so that the opening between the both ends of circular arc resistive layer21positionally corresponds to circular arc projection53, similarly to embodiment 1.

The input device of embodiment 2 has the above-mentioned structure, and is attached to a used apparatus similarly to embodiment 1 ofFIG. 3.

The operation of the input device is similar to that of embodiment 1 in the following points. While a predetermined voltage is applied to circular arc resistive layer21via first patterns22A and22B, operation body50is tilted to partially deflect substrate20with corresponding operation projection51(cylindrical projection52or circular arc projection53), thereby partially bringing circular arc resistive layer21into contact with metal plate31. When voltage obtained via second pattern35at this time is fed into control unit60and is calculated by control unit60, a total of 12 operation positions can be detected.

However, as discussed above, the input device of embodiment 2 differs from that of embodiment 1 in the arrangement state of the contact preventing unit and the operation state at a position between the both ends of circular arc resistive layer21during operation. The operation state is described hereinafter in detail. Operation state at the other angle position is the same as that in embodiment 1.

In the input device of embodiment 2, when operation body50is tilted in an angle direction between the both ends of circular arc resistive layer21, substrate20pressed by circular arc projection53is partially deflected at its pressed position to bring the corresponding part into contact with metal plate31.

At this time, as shown inFIG. 8, the both ends of circular arc resistive layer21do not simultaneously come into contact with metal plate31because island-like insulating layer75as a contact preventing unit is independently disposed between the both ends of circular arc resistive layer21. In other words, in the input device of the present invention, the contact preventing unit is formed of an island unit made of an insulating film formed between the both ends of circular arc resistive layer21. During operation at an angle position between the both ends of circular arc resistive layer21, metal plate31as a conductive layer comes into contact with one end21A as one end side of circular arc resistive layer21and island-like insulating layer75as the island unit. The other end21B as the other end side of circular arc resistive layer21is kept separate from metal plate31. Alternatively, island-like insulating layer75and the other end21B of circular arc resistive layer21come into contact with metal plate31, and one end21A is kept separate from it (not shown).

In the input device of embodiment 2, also, the both ends of circular arc resistive layer21do not simultaneously come into contact with metal plate31at angle positions between the both ends of circular arc resistive layer21. The detection state at the operation position or the like can be made similar to that at the other angle position. Also when operation body50is tilted in the angle direction close to the end, a similar operation state is obtained. However, detail description of this state is omitted similarly to embodiment 1.

It is important to form island-like insulating layer75in consideration of an operation force applied from operation body50during operation and elasticity of substrate20. For example, the thickness thereof is preferably equal to or slightly thicker than that of circular arc resistive layer21. Element unit70of the input device of embodiment 2 has independent island-like insulating layer75arranged in parallel with circular arc resistive layer21, so that element unit70can be thinned comparing with embodiment 1.

Element unit70of the input device of embodiment 2 may be a combination of principles of embodiment 1. In other words, one end side of island-like insulating layer75may be overlaid on one end21A of circular arc resistive layer21.

The input device of embodiment 2 has island-like insulating layer75formed of an insulating film; however, the input device may have an island unit formed of a conduct film independent from both ends of circular arc resistive layer21, and a similar advantage can be expected also in this case. In this case, it is reasonable to form the conduct film as the island unit using the same material as that of circular arc resistive layer21.

In the input device of embodiment 2, also, the shape of operation body50is not limited similarly to embodiment 1. The vertical arrangement relation between the conductive layer and the resistive layer may be opposite, similarly to the input device of embodiment 1.

A structure having a circular arc resistive layer and a contact preventing unit for preventing both ends of circular arc resistive layer21from simultaneously coming into contact with a conductive layer is within the scope of the present invention, even when the structure differs from the structures of embodiment 1 and embodiment 2. A circular arc resistive layer can be composed by elliptic arc shape, for example. The present invention can inexpensively achieve a thin input device that has high resolution comparing with the conventional art and can detect an operation position over substantially full circumference of the circular or elliptic ring part that is formed of the resistive layer and the opening between its both ends.