JP5806375B2 - Input device and portable terminal - Google Patents

Description

  The present invention relates to a key input device in a portable terminal or the like, and more particularly to an input device having a capacitive touch sensor.

Conventionally, an input device having a capacitive touch sensor is known (for example, see Patent Document 1).
A conventional input device is configured by arranging a plurality of capacitive touch sensors in a matrix on the surface of the device, and printing each display mark directly above the rectangular detection electrode of each sensor. It is detected by a change in the capacitance that the finger of the finger is very close or touched.

JP 2007-87878 A

By the way, in the portable terminal in which a plurality of small keys such as a cellular phone having a numeric keypad are arranged in a matrix at a narrow interval, the above-described technique is applied, and each key is placed directly above the electrode of the capacitive touch sensor. When the top display mark is printed, the following problem of erroneous input occurs.
When the operator tries to operate the target key from the group of keys arranged in a matrix, for example, with the index finger, the tip of the index finger not only touches the target key, but the index finger's belly touches the adjacent key in the same row. Or very close. For this reason, a change in capacitance is detected also for this adjacent key, and an erroneous input unintended by the operator occurs.

  The present invention has been made in view of the above problems, and an object thereof is to provide an input device capable of improving operability when a target key is operated.

  In order to solve the above problems, an input device according to the present invention is an input device in which a plurality of keys are arranged side by side in a column direction, and the keys are arranged behind the operation surface having key display marks. The key electrode portion has a shape in which the center of gravity of the electrode portion is located below the center of the rectangular area surrounding the key display mark in the column direction. It is characterized by having. Here, the key display mark is one or a plurality of characters (may be numerals), a figure, a symbol, a combination thereof, or the like.

  With the above configuration, the input device according to the present invention can improve the operability when operating the target key.

External view of mobile phone 10 provided with input device 100 Exploded perspective view of key group (A) Plan view of operation surface of key, (b) Diagram showing positional relationship between key display marks (A) The top view of the electrode plate arrangement surface of a key, (b) The figure which shows the dimension of an electrode plate Figure showing the operation surface transparently to show the positional relationship between the key display mark and the key electrode plate Explanation of operation of IC 230 for capacitive touch sensor Flow chart of input detection processing Explanatory drawing of finger contact position in key operation Illustration of key modification

Hereinafter, an input device 100 according to an embodiment of the present invention will be described with reference to the drawings.
<Configuration>
As shown in FIG. 1, an input device 100 is provided in a mobile phone 10 and has an operation surface on which key display marks such as numbers and arrows are drawn for each key group such as a numeric keypad and direction keys. The operator can input characters, telephone numbers, and the like by touching the key display mark with a finger.

  As shown in FIG. 2, the input device 100 is formed on the upper surface of a printed circuit board 220 formed by printing a plurality of electrode plates 221 constituting a capacitive touch sensor on a resin surface so as to be arranged in a matrix. And a structure formed by superimposing opaque insulating sheet members 210. An IC (Integrated Circuit) 230 for a capacitive touch sensor is disposed on the back surface of the printed circuit board 220, and each electrode plate 221 and each terminal of the IC 230 are connected to each other through wiring in the printed circuit board inner layer.

The upper surface of the opaque insulating sheet member 210 is an operation surface, and key display marks for each key are printed in a different color from the background on the operation surface.
As shown in FIG. 3A, the arrangement of the keys on the operation surface is a matrix (7 rows and 3 columns). For example, for the keys “3”, “6”, and “9”, “ The key display mark 211a, the key display mark 211b, and the key display mark 211e, which are surrounded by a rectangle with 3 ”,“ 6 ”, and“ 9 ”in the center, are arranged at equal intervals sequentially from the upper side in the column direction. Yes.

FIG. 4B shows the interval between adjacent keys on the operation surface, that is, the interval between adjacent key display mark groups 211a to 211d.
On the surface on which the electrode plates are arranged, as shown in FIG. 4A, the electrode plates for each key are arranged in a matrix (7 rows and 3 columns). It has the dimensions shown in (b).

FIG. 5 shows the positional relationship between the key display mark and the electrode plate of the key through the operation surface. As shown in FIGS. The electrode plate for detection is arranged behind the key display mark for the key.
That is, each key includes an operation surface portion on which a key display mark is drawn and an electrode plate disposed behind (underside) the key display mark. For example, behind the key display mark 211a of the “3” key, there is a “3” key electrode plate 221a with the center of the upper edge and the lower edge protruding downward. Behind the key display mark 211b is the electrode plate 221b for the key “6”.

In detail, the shape of the electrode plate 221 of each key is formed as a V-shaped polygonal line when viewed from above (the upper edge is a polygonal line connecting the vertex 401a, the vertex 401b, and the vertex 401c) The lower edge is a polygonal line connecting the vertex 401f, the vertex 401e and the vertex 401d.) The left and right edges of the electrode plate are the left and right sides of the rectangle forming the key display mark of the key, respectively. It is formed by a straight line that coincides with each of the edges (see FIGS. 4B and 5).

  As shown in FIG. 6, the IC 230 for the capacitive touch sensor has a circuit configuration of a pulse application unit 801, a resistor R802, a voltage measurement unit 803, a capacitance calculation unit 804, and a determination output unit 805, and includes a circuit board ground. When the operator's finger is in contact with or very close to the electrode plate by measuring the capacitance C of the capacitive element formed by the layer facing the electrode plates with the dielectric resin layer sandwiched between them An input detection process for detecting a change in the measured value of the capacitance C based on the generated stray capacitance, determining a key input, and outputting a signal indicating the input key is performed. Upon receiving the output of the IC 230, the control processor (not shown) of the mobile phone 10 performs a process corresponding to the input key, for example, a process of accepting a number corresponding to the key as a telephone number and making a call, A process for receiving a character corresponding to the text and creating a sentence that becomes the content of the e-mail for transmission is executed. Note that the stray capacitance described above has a large facing area between the finger and the electrode plate if the distance between the finger and the electrode plate is constant when the operator's finger is in contact with or very close to the electrode plate. The bigger it is.

The IC 230 performs the above-described measurement of the capacitance C as follows. That is, the pulse application unit 801 periodically applies a pulse wave to each electrode plate 221 constituting each key via the resistor R802, and the voltage measurement unit 803 connects each electrode plate to the ground potential. And the capacitance calculation unit 804 calculates the capacitance C of the capacitive element formed by the electrode plate and the ground layer based on the elapsed time until the voltage V changes from the threshold value V1 to V2. . For a certain key, when the capacitance C changes from a reference value, which is a value when no operation is performed by the operator, to a predetermined threshold or more, the operator's finger contacts the electrode plate constituting the key. As a result, the determination output unit 805 determines that a key input has been made. The predetermined threshold is set in advance so that the difference between the capacitance C and the reference value exceeds the predetermined threshold when the finger contacts a portion corresponding to an area of, for example, about 20% or more of the electrode plate. Is set.
<Operation of IC for capacitive touch sensor>
FIG. 7 is a flowchart showing input detection processing performed by the IC 230.

The IC 230 identifies the value of each capacitance C obtained through each electrode plate of each key arranged in 7 rows and 3 columns by, for example, the matrix number of what rows and columns. For example, the matrix number of the key “3” is row number 4 and column number 3, and the matrix number of the key “6” is row number 5 and column number 3 (see FIG. 3).
The IC 230 calculates the capacitance C measured through the electrode plates constituting each key (step S901), and if there is a capacitance change greater than a predetermined threshold, the corresponding matrix number is temporarily stored. Hold (steps S902 and S903), determine whether one or more keys are associated with the held matrix number (step S904), and if there is one, determine that key as the input key (step S904) In step S905, a signal indicating this key is output to the control processor of the mobile phone 10 (step S907). If it is determined in step S904 that there are a plurality of keys, the IC 230 selects a key having the largest change in the capacitance C corresponding to the plurality of keys and determines that the key has been input (step S906). ), A signal indicating this key (a signal indicating the matrix number) is output to the control processor of the mobile phone 10 (step S907).
<Operation status>
Hereinafter, determination of key input in the input device 100 when the operator performs key operation will be specifically described with reference to FIG.

When operating the input device 100 having an operation surface in which the key display marks of the keys are arranged in a matrix, the operator usually reads “3”, “6”, “9”, etc. of the input device 100. In order to make the drawn key display mark group easy to read, the key display mark of the “3” key is held above the key display mark of the “6” or “9” key, and FIG. Operate with your finger pointing in the direction shown in. In other words, the operator normally operates the key display mark with the upper direction in the column direction as the upper direction and the lower direction of the key display mark as the lower side in the column direction. Here, the upward and downward directions of the key display mark are the same as the upward and downward direction of the key display mark when the operator places the key display mark in a normal reading direction. When the key display mark is a character, among the tops and bottoms of the character, the top side is upward and the ground side is downward.

FIG. 8A shows a scene in which the operator operates the “3” key with the index finger.
FIG. 8B is a diagram in which a contact portion or a very close portion between the area of the key display mark of each key and the operator's finger in the operation shown in FIG. It is. 8B to 8D also show a finger range 1002 and a finger tip 1001 as an image of a finger assuming a finger operator of a standard size.

As shown in FIG. 8B, when a standard operator operates the “3” key, the tip 1001 of the index finger is aligned with the center of the key display mark 211a of the “3” key. In addition, the belly of the index finger is in contact with or very close to the key display mark 211b of the “6” key.
FIG. 8C is a diagram in which the contact portion between the electrode plate of each key and the operator's finger in the operation shown in FIG.

  As shown in FIG. 8C, when the operator operates the key “3”, the tip of the index finger comes into contact with the electrode plate 221a of the key “3”, and the index finger has the belly “6”. It is in contact with or very close to the electrode plate 221b of the key. Since the upper edge and the lower edge of each electrode plate have a V-shaped broken line, the area of the portion 1004a where the finger and the electrode plate 221a of the key “3” are in contact with or very close to each other is “6” The key electrode plate 221b is larger than the area of the portion 1004b in contact with or very close to. Therefore, for this operation, the IC 230 does not use the “6” key in step S906 of the input detection process, but the key having a capacitance of “6” due to the relatively large area of the portion 1004b. It is determined that the key “3”, which is larger than the key, is input.

  FIG. 8D shows the contact portion between the electrode plate of each key and the operator's finger when the operator operates the key “3” with the index finger slightly tilted, or a portion in close proximity with hatching. FIG. As described above, even when the operation is performed with a slight tilt of the finger, each electrode plate has a V-shape, and therefore the area of the portion 1004c where the finger and the electrode plate 221a of the “3” key are in contact or very close to each other is The area of the portion 1004d where the finger and the electrode plate 221b of the key “6” are in contact with or very close to each other is larger. Therefore, even if the operation is performed by tilting the finger, the IC 230 determines that the “3” key is input instead of the “6” key in step S906 of the input detection process.

As described above, the input device according to the present invention does not match the center of the key display mark of each key and the center of gravity of the electrode plate as in the prior art. The center of gravity (the center of the rectangular area surrounding the key display mark) is shifted from the center to the lower side in the column direction. Therefore, when the operator tries to operate with the index finger of the target key, for example, with the index finger, when the tip of the index finger comes into contact with the target key, There is a high possibility that the detection is not included in the detection range of the electrode plate of the adjacent key on the lower side in the column direction of the target key. That is, this input device can prevent an erroneous input that is not intended by the operator, and the operability is improved.
<Modification>
Although the embodiment of the input device according to the present invention has been described above, the illustrated input device 100 can be modified as follows, and the present invention is applied to the input device 100 as shown in the above-described embodiment. Of course, it is not limited.

(1) The key display mark of each key shown in the above embodiment is a character, arrow, etc. enclosed in a rectangle, but even if a plurality of characters are included in one key display mark. For example, “2” and “ABC” arranged with a space between them may be used as a key display mark corresponding to one key. Further, in FIG. 3A and the like, a key display mark in which the character “3” is surrounded by a rectangular frame is shown, but there is no problem even if there is no rectangular frame.

The key display mark is printed in a different color from the background. However, the key display mark does not need to be printed as long as it is displayed by a method visually recognized by the operator. For example, the mark is engraved on the operation surface. Alternatively, the mark may be displayed on the operation surface so that the mark emerges from the back side with a light source such as an LED (Light Emitting Diode).
(2) In each key shown in the above-described embodiment, the electrode plate serving as a part of the capacitive touch sensor has the dimensions and shape shown in FIG. Although the positional relationship with the board is as shown in FIG. 5, each key is not limited to this. That is, in plan view, the center of gravity of the electrode plate shape for each key is positioned below the center of the key display mark for each key or the center of the rectangle surrounding the character in the key display mark. If arranged, each key need not have the dimensions, shape and arrangement shown in the above embodiment. However, the electrode plate for a key includes at least part of the key display mark for the key in front of the electrode plate region range in plan view, and the key display mark for the other key. It is necessary to arrange at a position that does not include part or all of it.

For example, as shown in FIG. 9A, the key may be such that the center of gravity 1102 of the electrode plate 221h is below the center 1101 of the key display mark consisting of only the character “3”. Similarly, the keys shown in FIGS. 9B to 9G may be used. In FIG. 9, only the key “3” is shown, but the same applies to other keys.
If the shape of each electrode plate is a shape in which the upper edge and the lower edge are downwardly convex arcs as in the example of FIG. If the key is operated at any angle, the contact area to the target key will be larger than the contact area to the other key in the same row and one row below. By the IC for the capacitive touch sensor, it is determined that the target key is inputted instead of the other keys in the lower row. The arc may be a circular arc.

  Moreover, the shape of the electrode plate may not be symmetrical. However, if left and right are symmetric, the operator reacts in the same manner regardless of whether the operator tilts the finger to the right or to the left. In addition, even if the center (center of gravity) of the contour of the electrode plate is aligned with the center of the key display mark, in the plan view, a shape in which a plurality of holes are formed on the upper side of the electrode plate is used. The true center of gravity may be shifted below the viewed center of gravity.

(3) Although the IC for the capacitive touch sensor described above measures the change in capacitance between the electrode plate of each key and the ground layer, it determines the key input. The method and the key input determination procedure may be other methods. For example, the thresholds V1 and V2 to be compared with the measured voltage and the predetermined threshold to be compared with the difference between the measured value of the capacitance C and the reference value are adjusted to appropriate values by experiments or the like in the design or manufacturing stage of the input device. You may decide. Also, for example, in step S906 (FIG. 7) of the input detection process, when there are a plurality of keys whose capacitance change exceeds a predetermined threshold, the key with the largest capacitance change is selected and input. However, the key having the smallest row number indicated by the matrix number, that is, the key positioned at the uppermost side may be selected and determined as the input key. In step S907, a signal for identifying some key may be output instead of the signal indicating the matrix number. Further, the function sharing between the control processor of the mobile phone and the IC can also be changed, and it is only necessary to be able to identify which key is input by the operator in the mobile phone.

(4) In the above-described embodiment, as shown in FIG. 4, the center of gravity of the shape of all the electrode plates of each key is arranged on the lower side. It is good also as arrange | positioning so that the gravity center of the shape of at least any one electrode plate of a plate may be located below.
In the embodiment described above, as shown in FIG. 4, the shape of all the electrode plates of each key is the same, but the shape of the electrode plate of each key may be different. Good.

In the above-described embodiment, as shown in FIG. 4, the upper edge of the electrode plate of the key in the uppermost row of the matrix is convex downward, but the key in the uppermost row of the matrix has a key on the upper side thereof. Since it does not exist, the upper edge of the key electrode plate in the uppermost row of this matrix may have a shape that does not protrude downward.
In the above-described embodiment, as shown in FIG. 4, the lower edge of the electrode plate of the key in the bottom row of the matrix is convex downward, but the key in the bottom row of the matrix is the key on the lower side. Therefore, the lower edge of the key electrode plate in the bottom row of this matrix may have a shape that does not protrude downward.

Further, in the above-described embodiment, as shown in FIG. 4, both the upper edge and the lower edge of the electrode plate are convex downward, but the center of gravity of the shape of the electrode plate is located on the lower side. Therefore, at least one of the upper edge and the lower edge of the electrode plate may be convex downward.
(5) You may combine the above-mentioned embodiment and each modification partially.
(6) Hereinafter, the configuration as an embodiment of the input device and the portable terminal according to the present invention, and its modifications and effects will be described.

  (A) An input device according to an embodiment of the present invention is an input device in which a plurality of keys are arranged side by side in a column direction, and the keys are arranged on and behind an operation surface having a key display mark. The key electrode portion has a shape in which the center of gravity of the electrode portion is located below the center of the rectangular area surrounding the key display mark in the column direction. It is characterized by having. When characters are included in the key display mark, the ground side in the top and bottom of the characters coincides with the lower side in the column direction. With this configuration, for each key, the center of gravity of the electrode portion is lower in the column direction than the center of the rectangular area surrounding the key display mark (for example, the center of the smallest rectangular area surrounding the key display mark, in other words, the center of the key display mark). If the operator tries to operate with the index finger of the key display mark of a certain target key, for example, when the tip of the index finger touches the target key, the index finger The antinode is included in the detection range of the electrode portion for the target key, and the possibility that the antinode is not included in the detection range of the electrode portion for the adjacent key on the lower side in the column direction of the target key increases. Therefore, this input device can prevent an erroneous input unintended by the operator, and the operability is improved.

  (B) In the input device, the shape of the electrode portion of the key may be a shape having at least one of an upper edge and a lower edge that protrude downward in a plan view. With this configuration, since at least one of the upper edge and the lower edge of each electrode plate is convex downward, the operator operates the upper key among a plurality of keys arranged in a row. When the tip of a finger is brought into contact with the target key, the area where the key electrode plate under the target key and the belly of the finger face each other can be kept small. It becomes possible to prevent this, and operability is improved.

(C) At least one of the upper edge and the lower edge in the shape of the key electrode portion of the input device may be a V-shaped broken line. The left edge and the right edge in the shape of the electrode portion of the key may be straight lines in the vertical direction. Further, the shape of the electrode plate of the key may be bilaterally symmetric in plan view. With this configuration, even if the operator slightly tilts his / her finger to the right (see FIG. 8D) or slightly tilts to the left, it is possible to prevent erroneous input, thereby improving operability. .

  (D) At least one of the upper edge and the lower edge in the shape of the key electrode portion of the input device may be an arc. As a result, when the operator operates the key by tilting his / her finger at an angle within the range of the central angle of the arc, it is possible to prevent erroneous input, and operability is improved.

  (E) A portable terminal including an input device according to an embodiment of the present invention includes a plurality of operations including an operation surface having a key display mark and an electrode portion of a capacitive touch sensor arranged behind the operation surface. A portable terminal including a numeric keypad in which keys are arranged in M rows and N columns (M ≧ 2, N ≧ 1), and the electrode portion of the key is a rectangle in which the center of gravity of the electrode portion surrounds the key display mark It has a shape located on the lower side in the column direction from the center of the region. With this configuration, it is possible to prevent erroneous input of the numeric keypad that is not intended by the operator, and operability is improved.

  INDUSTRIAL APPLICABILITY The input device according to the present invention can prevent erroneous input related to adjacent keys when a target key is operated, and is useful for use in a mobile phone or the like.

10 Mobile phone
100 input devices
210 Insulation sheet member
211 Key display mark
220 Printed circuit board
221 Electrode plate (electrode part)
230 IC

Claims (7)

An input device in which a plurality of keys are arranged side by side in a row direction and a column direction,
Each of the plurality of keys includes an operation surface having a key display mark and an electrode portion of a capacitive touch sensor arranged behind the operation surface.
The electrode portions of the plurality of keys have the same shape and are arranged in a straight line in the row direction,
The input device, wherein an upper edge of the electrode portion is located in a region surrounding the key display mark corresponding to the electrode portion, and a lower edge of the electrode portion is located outside the region. 2. The input device according to claim 1, wherein the shape of the electrode portion of the key is a shape having at least one of an upper edge and a lower edge that protrude downward in a plan view. The input device according to claim 2, wherein at least one of an upper edge and a lower edge in the shape of the electrode portion of the key is a V-shaped broken line. The input device according to claim 3, wherein the shape of the electrode portion of the key is symmetrical in a plan view. The input device according to claim 2, wherein at least one of an upper edge and a lower edge in the shape of the electrode portion of the key is an arc. The input device according to claim 2, wherein a left edge and a right edge in the shape of the electrode portion of the key are straight lines in the vertical direction. An input device in which a plurality of keys are arranged side by side in a row direction and a column direction,
Each of the plurality of keys includes an operation surface having a key display mark and a detection unit that detects contact or proximity to the operation surface.
The detection ranges of the detection units of the plurality of keys have the same shape in a plan view and are arranged so as to be aligned on a straight line in the row direction,
An input device, wherein an upper edge of the detection range is located in an area surrounding the key display mark corresponding to the detection range, and a lower edge of the detection range is located outside the area.

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