JP2016200473A - Pressure distribution sensor, input device, electronic apparatus, and sensor chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure distribution sensor capable of accurately detecting pressure distribution without requiring a plurality of pressure sensors.SOLUTION: A pressure distribution sensor 1 comprises a sensor IC 11 including m pieces of pressure sensitive elements encapsulated in a package with a square top face (wherein m is an integer of 4 or more) and a cap member 12 with an n-sided polygonal (wherein n is an integer larger than 4) or circular top face for covering the sensor IC 11, so as to make a close contact with the top and side faces of the sensor 11.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pressure distribution sensor, an input device and an electronic apparatus using the pressure distribution sensor, and a sensor chip used therefor.

  In a conventional direction input device (cross key, analog stick, etc.), a pressure sensor for detecting pressure is prepared for each of a plurality of operation directions (for example, up, down, left, and right), and according to each sensor output. A user input operation was detected.

  As an example of the related art related to the above, Patent Document 1 can be cited.

JP-A-7-261926

  However, since the conventional direction input device requires a plurality of pressure sensors, it is difficult to reduce the size and cost of the device, and calibration between the pressure sensors is also required.

  In view of the above-mentioned problems found by the inventors of the present application, the invention disclosed in this specification is a pressure distribution sensor capable of correctly detecting a pressure distribution without requiring a plurality of pressure sensors, and this It is an object of the present invention to provide an input device and an electronic device using the sensor, and a sensor chip used for the same.

  The pressure distribution sensor disclosed in the present specification includes a sensor IC in which m pressure-sensitive elements are sealed in a package whose upper surface is a quadrangular shape (where m is an integer of 4 or more), and And a cap member that covers the sensor IC so that the upper surface has an n-corner shape (where n is an integer greater than 4) or a circular shape and is in close contact with the upper surface and the side surface of the sensor IC (first Composition).

  In the pressure distribution sensor having the first configuration, the m and the n may each be a multiple of 4 that is 8 or more (second configuration).

  In the pressure distribution sensor having the first or second configuration, the cap member may be disposed on the sensor IC such that four of the n vertices are on a straight line connecting the diagonals of the sensor IC. A covered configuration (third configuration) is preferable.

  The pressure distribution sensor having any one of the first to third configurations may be configured to be mounted on a printed wiring board (fourth configuration) so that the four vertices correspond to the vertical and horizontal directions, respectively. .

  In the pressure distribution sensor having any one of the first to fourth configurations, the m pressure-sensitive elements may be configured to be integrated in a single sensor chip (fifth configuration).

  In the pressure distribution sensor having the fifth configuration, the m pressure-sensitive elements may be configured to have the same shape (sixth configuration).

  In the pressure distribution sensor having the fifth or sixth configuration, four of the m pressure-sensitive elements are on a line segment connecting the center point of the sensor chip and the four vertices of the sensor chip. It is good to make it the structure (7th structure) arrange | positioned circularly on the said sensor chip so that it may be located.

  Further, in the pressure distribution sensor having any one of the fifth to seventh configurations, the m pressure-sensitive elements are formed radially on the sensor chip with respective longitudinal directions directed toward the center of the sensor chip. (8th configuration).

  Further, in the pressure distribution sensor having any one of the fifth to eighth configurations, the sensor chip has a plurality of pads for drawing out connection nodes between the pressure sensitive elements to the outside of the chip (the ninth). (Configuration).

  Further, in the pressure distribution sensor having any one of the fifth to eighth configurations, the sensor chip has a plurality of pads for drawing out both end nodes of each pressure sensitive element to the outside of the chip (a tenth configuration). Configuration).

  An input device disclosed in the present specification includes a casing, a printed wiring board supported by the casing, and any one of the first to tenth configurations mounted on the printed wiring board. And a plate-like member placed on the upper surface of the pressure distribution sensor so as to incline in a direction according to a user's direction input operation (an eleventh configuration).

  In the input device having the eleventh configuration, the plate-like member may have a configuration (a twelfth configuration) in which an upper surface of the plate member is a shape obtained by enlarging the upper surface of the pressure distribution sensor.

  In the input device having the eleventh or twelfth configuration, the inclination of the plate-like member is limited by the outer edge of the plate member being in contact with the casing, the printed wiring board, or the contact member. (13th configuration).

  In addition, the input device having any one of the above-described configurations of the first to thirteenth configurations may have a configuration (fourteenth configuration) that further includes an elastic member that covers the pressure distribution sensor and supports the plate-like member.

  In the input device having any one of the above-described configurations of the first to fourteenth configurations, the casing includes a protrusion that supports the printed wiring board at one point on the back side of the mounting position of the pressure distribution sensor (first 15 configuration).

  Further, in the input device having any one of the above-described first to fifteenth configurations, the pad connection state of the sensor chip so that the m pressure-sensitive elements are divided into four pressure-sensitive element groups to form a bridge circuit. A pad switching unit for switching the output, an output detection unit for detecting the output of the bridge circuit, and a logic unit for receiving a detection result of the output detection unit to determine a user input operation (sixteenth configuration) It is good to.

  In the input device having the sixteenth configuration, the pressure-sensitive element group may have a configuration (a seventeenth configuration) designed such that the combined resistance values when no pressure is applied are the same.

  In the input device having the sixteenth or seventeenth configuration, the pad switching unit may be configured to sequentially switch the division pattern of the pressure-sensitive element group (eighteenth configuration).

  In the input device having the eighteenth configuration, the pad switching unit may invert the first output end and the second output end of the bridge circuit for each divided pattern of the pressure-sensitive element group. (Nineteenth configuration) is preferable.

  In addition, the electronic device disclosed in the present specification has a configuration (twentieth configuration) having an input device having any one of the above-described first to nineteenth configurations.

  In addition, the pressure distribution sensor disclosed in the present specification includes a sensor IC that detects a pressure distribution applied to a package whose upper surface is a quadrangular shape, and an upper surface having an n-square shape (where n is greater than 8). 4) and a cap member that covers the sensor IC so as to be in close contact with the upper surface and the side surface of the sensor IC. The sensor IC is configured to be positioned on a straight line connecting the corners (a twenty-first configuration).

  In addition, the input device disclosed in this specification includes a pressure distribution sensor including m pressure sensors (where m is a multiple of 4 that is 8 or more), and four m pressure sensitive elements. A pad switching unit that switches the pad connection state of the sensor chip so as to divide into pressure-sensitive element groups to form a bridge circuit, an output detection unit that detects an output of the bridge circuit, and a detection result of the output detection unit And a logic unit (a twenty-second configuration) for receiving and determining a user's input operation.

  The sensor chip disclosed in the present specification has a square shape formed by integrating a plurality of pressure-sensitive elements, and is arranged on a line segment connecting the center point and the four vertices of the sensor chip. The pressure sensitive element has a configuration (23rd configuration) provided closer to the center point than the pressure sensitive elements arranged at other positions.

  Further, in the pressure distribution sensor having any one of the fifth to eighth configurations, the m pressure-sensitive elements are provided in an annular shape at substantially equal intervals around the center point of the sensor chip ( (24th configuration)

  In the pressure distribution sensor having any one of the fifth to eighth configurations, the sensor IC has a square upper surface of the package, and the four apexes of the package are the center point of the sensor chip and the sensor chip. It is preferable to adopt a configuration (25th configuration) that is located on an extension line of a line connecting the four vertices.

  In the pressure distribution sensor having any one of the fifth to eighth configurations, the cap member has an n-side upper surface, and four vertices of the n vertices of the cap member are the center of the sensor chip. It is preferable to adopt a configuration (26th configuration) that is located on an extension line of a line connecting the point and the four vertices of the sensor chip.

  In the pressure distribution sensor having any one of the fifth to eighth configurations, the top surface of the cap member has an m-corner shape, and the m vertex of the cap member is the center point of the sensor chip and the m A configuration (a twenty-seventh configuration) may be employed that is positioned on an extension line of each line connecting the pressure-sensitive elements.

  In the input device having the eleventh configuration, the plate-like member may have a configuration (28th configuration) in which the upper surface has an n-corner shape or a polygonal shape.

  In the input device having the eleventh configuration, each of the pressure distribution sensor and the plate-like member has an n-shaped upper surface, and the apex of the pressure distribution sensor and the plate-like member. The apexes may be configured to be directed in directions shifted by 360 / 2n degrees in the top view (29th configuration).

  In the input device having the eleventh configuration, the upper surface of the pressure distribution sensor may have an n-corner shape, and the upper surface of the plate member may have a circular shape (30th configuration).

  Moreover, the input device which consists of the said 11th structure WHEREIN: The said plate-shaped member is good to make it a structure (31st structure) provided with a recessed part in the surface facing the said pressure distribution sensor.

  In addition, the input device disclosed in the present specification generates a sensor IC that detects a distribution of pressure applied to the upper surface of the package, and a pressure distribution corresponding to a user's direction input operation on the upper surface of the package of the sensor IC. An urging member, and the urging member has a plurality of leaf spring portions each having a tip opposed to the package upper surface of the sensor IC, and the leaf spring portions are arranged radially around the sensor IC. And a connecting portion that connects the respective root ends in a ring shape (a thirty-second configuration).

  In the input device having the thirty-second configuration, the connecting portion may be configured to be fixed to a printed wiring board together with the sensor IC (a thirty-third configuration).

  In the input device having the thirty-second or thirty-third configuration, the plurality of leaf springs may have a configuration in which each tip is bent toward the upper surface of the package of the sensor IC (a thirty-fourth configuration). Good.

  In the input device having any one of the thirty-second to thirty-fourth configurations, each of the plurality of leaf springs may have a trapezoidal shape (thirty-fifth configuration) that becomes narrower toward the tip. .

  Further, the input device having any one of the thirty-second to thirty-fifth configurations may have a configuration (a thirty-sixth configuration) further including a columnar member that bends the plurality of leaf spring portions in response to a user's direction input operation. .

  According to the invention disclosed in this specification, a pressure distribution sensor capable of correctly detecting a pressure distribution without requiring a plurality of pressure sensors, an input device and an electronic apparatus using the pressure distribution sensor, and a device used for the pressure distribution sensor It is possible to provide a sensor chip.

External view showing a configuration example of the electronic device X Schematic diagram showing the first embodiment of the pressure distribution sensor 1 Schematic diagram showing a second embodiment of the pressure distribution sensor 1 Longitudinal sectional view showing a first embodiment of the direction input device X1 Top view showing one shape example of the cap member 12 and the plate-like member 130 Longitudinal sectional view showing a second embodiment of the direction input device X1 Longitudinal sectional view showing a third embodiment of the direction input device X1 The block diagram which shows one structural example of the sensor chip 10 and the arithmetic processing chip 20 Table showing first example of pad switching control Table showing second example of pad switching control Schematic diagram showing a variation of the output detection technique Schematic diagram showing a modification of the sensor chip 10 The schematic diagram which shows one structural example of the sensor chip 10 which does not require the cap member 12 Longitudinal sectional view showing a modification of the plate member 130 The figure which shows the example of 1 application of the biasing member 160 The figure which shows the cross-sectional shape of the columnar member 140 suitable for the pressure transmission to the biasing member 160

<Electronic equipment>
FIG. 1 is an external view illustrating a configuration example of the electronic apparatus X. The electronic device X of this configuration example is provided to the user as a game device, and includes a direction input device X1, a button X2, and a display screen X3. In addition to the above-described components, the electronic device X can be appropriately equipped with a microphone, a speaker, a camera, and the like (not shown).

  The direction input device X1 is a user interface (such as a cross key or an analog stick) for moving a character or cursor displayed on the display screen X3 in an arbitrary direction. For example, the direction input device X1 can be operated in any operation direction (upward U, downward D, left direction L, right direction R, upper left direction UL, lower left direction DL, upper right direction UR, lower right direction DR by the user's left thumb. Etc.).

  A single pressure distribution sensor 1 is mounted at the center of the direction input device X1 as means for detecting the pressure distribution given to the direction input device X1. In the direction input device X1, based on the sensor output of the pressure distribution sensor 1, the operation state of the direction input device X1 (a state in which the direction input device X1 is pressed in one of the up, down, left, and right directions, a state in which the central portion is pressed right below, or In other words, it is possible to determine a state where the button is not pressed at all, and a degree of pressing (strength).

  Thus, with the direction input device X1 of this configuration example, there is no need to provide a pressure sensor for each of a plurality of operation directions. Therefore, it is easy to reduce the size and cost of the apparatus, and it becomes unnecessary to perform calibration between pressure sensors. In addition, a plurality of pressure-sensitive elements integrated in the pressure distribution sensor 1 (details will be described later) all exhibit similar characteristics. Therefore, calibration between the pressure sensitive elements is facilitated. The configuration of the pressure distribution sensor 1 and the pressure transmission mechanism to the pressure distribution sensor 1 will be described in detail later.

  The button X2 is a user interface for causing the character displayed on the display screen X3 to perform an arbitrary action, or to determine or cancel a cursor selection item. For example, the button X2 is pressed by the user's right thumb.

  The display screen X3 is a user interface for displaying characters and cursors. Note that a touch panel that accepts a user's tap operation, flick operation, or the like can be mounted on the display screen X3.

<Pressure distribution sensor>
FIG. 2 is a schematic diagram showing the first embodiment of the pressure distribution sensor 1 (a column is a top view, and b column is a side view). In addition, the broken line in this figure transparently describes the internal structure which cannot be observed directly from the upper surface or side surface of the pressure distribution sensor 1. As shown in the figure, the pressure distribution sensor 1 of the present embodiment includes a sensor IC 11 and a cap member 12.

  The sensor IC 11 is a semiconductor integrated circuit device formed by sealing the sensor chip 10 with resin. In the sensor chip 10, m pressure sensitive elements R * (where * = 1, 2,..., M) are integrated as means for detecting an omnidirectional pressure distribution given to the direction input device X1. Yes. m may be an integer of 4 or more, and in particular, m is preferably a multiple of 4 (8, 12, 16,...) of 8 or more. In the example of this figure, m = 8 is designed. As the pressure sensitive element R *, a piezoresistor whose resistance value changes according to the stress received may be used.

  The sensor chip 10 is cut out from the semiconductor wafer into a quadrangular shape (in the example of this figure, a square shape). In such a quadrangular sensor chip 10, stress tends to concentrate on the four vertices. In view of this, four of the pressure sensitive elements R1 to R8 (R2, R4, R6, and R8 in the example of this figure) are the center point O of the sensor chip 10 (in the present specification, for convenience of explanation). The intersection of diagonal lines in the top view of the sensor chip 10 is referred to as a “center point O” and the sensor chip so as to be positioned on a line segment connecting the four vertices (a2, a4, a6, a8) of the sensor chip 10. 10 is arranged in a ring shape. The bridge circuit forming operation and detection operation using the pressure sensitive elements R1 to R8 will be described in detail later.

  By the way, in order to correctly detect the omnidirectional pressure distribution with the sensor IC 11 described above, the upper surface of the package of the sensor IC 11 may be formed in an n-corner shape (where n is an integer greater than 4) or a circular shape. desirable. However, since the sensor chip 10 has a quadrangular shape, it is disadvantageous in terms of yield and the like that it is not practical to form a package upper surface of the sensor IC 10 formed by resin-sealing the sensor chip 10 other than the quadrangular shape.

  Therefore, the pressure distribution sensor 1 of the first embodiment is configured such that the cap member 12 is covered with the sensor IC 11 as means for making the upper surface of the pressure distribution sensor 1 have an arbitrary shape. More specifically, the upper surface of the cap member 12 has an n-corner shape (a regular octagonal shape in the example of this figure), and is placed on the sensor IC 11 so as to be in close contact with the upper surface and side surfaces of the sensor IC 11. .

  The cap member 12 is placed on the sensor IC 11 so that four vertices (c2, c4, c6, c8) of the eight vertices (c1 to c8) are positioned on a straight line connecting the diagonals of the sensor IC11. ing. That is, the four vertices (c2, c4, c6, c8) of the cap member 12 are the four vertices (b2, b4, b6, b8) of the sensor IC 11 (by extension, the four vertices (a2, a4, The sensor IC 11 is placed so as to be associated with a6, a8)).

  With such a configuration, the stress concentration position of the cap member 12 and the stress concentration position of the sensor IC 11 (and hence the stress concentration position of the sensor chip 10) can be matched, so that the omnidirectional pressure distribution Can be detected correctly.

  Further, in the pressure distribution sensor 1, the four vertices (c2, c4, c6, c8) of the cap member 12 correspond to the vertical and horizontal directions (upward U, leftward L, downward D, rightward R), respectively. Mounted on a printed wiring board. That is, the vertex a2 of the sensor chip 10, the vertex b2 of the sensor IC 11, and the vertex c2 of the cap member 12 are associated with the upward direction U, respectively. The vertex a4 of the sensor chip 10, the vertex b4 of the sensor IC 11, and the vertex c4 of the cap member 12 are associated with the left direction L, respectively. The vertex a6 of the sensor chip 10, the vertex b6 of the sensor IC 11, and the vertex c6 of the cap member 12 are associated with the downward direction D, respectively. The vertex a8 of the sensor chip 10, the vertex b8 of the sensor IC 11, and the vertex c8 of the cap member 12 are associated with the right direction R, respectively.

  With such a configuration, it is possible to correctly detect the pressure distribution in the vertical and horizontal directions as the main direction among the omnidirectional pressure distributions to be detected.

  FIG. 3 is a schematic view showing a second embodiment of the pressure distribution sensor 1 (a column is a top view, and b column is a side view). The pressure distribution sensor 1 of this embodiment is basically the same as that of the first embodiment (FIG. 2), but the top surface of the cap member 12 is not a regular n-square shape but a circular shape.

  In the case of the pressure distribution sensor 1 of the present embodiment, unlike the first embodiment (FIG. 2), the apex position of the sensor IC 11 and the apex position of the cap member 12 are combined, or the apex position of the cap member 12 is set. There is no need to correlate with the vertical and horizontal directions.

  However, the four vertices (b2, b4, b6, b8) of the sensor IC 11 (and hence the four vertices (a2, a4, a6, a8) of the sensor chip 10) are the first embodiment (FIG. 2). Similarly, it is desirable that the pressure distribution sensor 1 is mounted on the printed wiring board so as to correspond to the vertical and horizontal directions (upward direction U, leftward direction L, downward direction D, and rightward direction R).

<Supplementary information on high sensitivity>
It supplements about the high sensitivity of the pressure distribution sensor 1. FIG. In the sensor chip 10, the pressure sensitive elements R <b> 1 to R <b> 8 are desirably provided in an annular shape with a substantially uniform interval around the center point O of the sensor chip 10. In the sensor chip 10 cut out in a square shape, the four vertices (a2, a4, a6, a8) farthest from the center point O are the points (high sensitivity points) that are most strongly subjected to bending pressure / strain. Therefore, four of the pressure sensitive elements R1 to R8 (R2, R4, R6, and R8) are connected to the center point O of the sensor chip 10 and the four vertices (a2, a4, a6, a8). It is desirable to place each on a line segment of a book. Also, for the sensor IC 11 whose top surface is square (including chamfered ones), its four vertices (b2, b4, b6, b8) are positioned on the extension lines of the line segments. Is desirable. Furthermore, it is preferable that the top n-shaped cap member 12 has four vertices (for example, c2, c4, c6, and c8) among the n vertices positioned on the extension line of the line segment.

  When eight pressure sensitive elements R1 to R8 are integrated in the sensor chip 10, four pressure sensitive elements (R2, R4, R6, R8) are arranged on the four line segments, respectively, and the rest Four pressure sensitive elements (R1, R3, R5, R7) are respectively arranged in regions sandwiched between the line segments. At this time, when the upper surface of the cap member 12 is octagonal according to the number of the pressure sensitive elements R1 to R8, a line segment connecting the center point O of the sensor chip 10 and the pressure sensitive elements R1 to R8. It is desirable that the eight vertices (c1 to c8) of the cap member 12 be positioned on the extended line.

<Direction input device>
FIG. 4 is a longitudinal sectional view showing a first embodiment of the direction input device X1. (A) column shows a state where no input operation is performed on the direction input device X1, (b) column shows a state where an input operation on the right side of the drawing is performed on the direction input device X1, and (c) column shows a direction input. This shows a state in which an input operation in the left direction of the drawing is being performed on the device X1.

  As shown in the figure, the direction input device X1 of the present embodiment includes a housing 110, a printed wiring board 120, a plate member 130, and a columnar member 140 in addition to the pressure distribution sensor 1 described above. And having.

  The housing 110 is a rigid member for carrying the direction input device X1, and the housing of the electronic device X (see FIG. 1) corresponds to this. Note that a support portion 110 a for supporting the printed wiring board 120 and a wall portion 110 b for limiting horizontal displacement of the plate-like member 130 are formed on the inner surface of the housing 110.

  The printed wiring board 120 is supported by the support part 110a of the housing 110, and the pressure distribution sensor 1 is mounted on the surface thereof.

  The plate-like member 130 is placed on the upper surface of the pressure distribution sensor 1 so as to be inclined in a direction corresponding to the user's direction input operation. Accordingly, the pressure distribution sensor 1 has a pressure distribution corresponding to the inclination of the plate-like member 130. Therefore, by detecting the sensor output, the operation state of the direction input device X1 (pressed in either the up / down / left / right direction) is detected. A state in which the center portion is pressed right below, or a state in which the center portion is not pressed at all).

  The plate member 130 has its outer edge end in contact with the housing 110 or the printed wiring board 120, so that the amount of inclination is limited (see column (b) or (c) in this figure). ). Alternatively, even if the inclination amount of the plate-like member 130 is limited by a resin-made contact member (not shown) installed in parallel (or substantially parallel) to the top surface of the housing 110 or the printed wiring board 120. Good. If such a contact member is used, direct contact between the casing 110 or the printed wiring board 120 and the plate member 130 can be prevented, so that the direction input device X1 (and thus the electronic device X) can be prevented. Durability can be improved. Further, the horizontal displacement of the plate-like member 130 is limited by the wall portion 110 b provided on the inner surface of the housing 110.

  FIG. 5 is a top view showing one shape example (including a combination of both) of the cap member 12 and the plate-like member 130. In addition, the broken line in this figure transparently depicts the lower structure that cannot be observed directly from the upper surface of the plate member 130.

  In the column (a), the shape of the upper surface of the plate-like member 130 is a shape in which the upper surface of the pressure distribution sensor 1 (and thus the upper surface of the cap member 12) is similarly enlarged. Each vertex is directed in the same direction.

  In the case of such a combination, for example, in the first state when the direction input device X1 is pressed in the right direction R, the vertex d8 of the plate-like member 130 contacts the printed wiring board 120, and the vertex c8 of the cap member 12 The greatest pressure is applied. Further, in the second state when the direction input device X1 is pressed in the upper right direction UR, the vertex d1 of the plate member 130 contacts the printed wiring board 120, and the largest pressure is applied to the vertex c1 of the cap member 12. Join.

  Next, when the pressing state of the direction input device X1 gradually changes from the first state to the second state, that is, the fingertip pressing the direction input device X1 moves from the right direction R to the upper right direction UR. Let's consider the case of moving slowly and linearly. In this case, first, after the apex d8 of the plate-like member 130 contacts the printed wiring board 120, the apex d8 and the printed wiring board until the side connecting the apex d8 and the apex d1 contacts the printed wiring board 120. The contact state with 120 is maintained. Thereafter, the moment when the edge connecting the vertex d8 and the vertex d1 comes into contact with the printed wiring board 120, and immediately after that, the vertex d1 comes into contact with the printed wiring board 120. At this time, the minute deformation in the right direction R of the cap member 12 (or sensor IC 11) and the minute deformation in the right direction R of the printed wiring board 120 are gradually released, and the pressure applied to the cap member 12 is changed to the right. Move to UR.

  Also, in the column (b), the apexes of the regular octagonal cap member 12 and the plate-like member 130 are shifted by 22.5 degrees respectively (360 / 2n degrees if both are generalized as a regular n-corner shape). It is pointed in the direction.

  In the case of such a combination, for example, when the direction input device X1 is pressed in the right direction R, the side connecting the vertex d7 and the vertex d8 of the plate-like member 130 comes into contact with the printed wiring board 120. Therefore, as compared with the structure in the column (a), it is possible to perform the pressing in the right direction R stably. Further, it is possible to apply more pressure to the cap member 12 (or the sensor IC 11) than in the state where only the vertex d8 is in contact with the printed wiring board 120.

  Furthermore, when the fingertip that presses the direction input device X1 is moved from the right direction R toward the upper right direction UR, the vertex d8 of the plate-like member 130 is in a state of instantaneously contacting the printed wiring board 120. As a result, the side connecting the vertex d8 and the vertex d1 comes into contact with the printed wiring board 120. Therefore, the pressure applied to the cap member 12 (or the sensor IC 11) temporarily decreases at the timing when the apex d8 contacts the printed wiring board 120.

  In view of the above, the combination in the column (b) indicates that the input operation in the main direction is more than the input operation in the intermediate direction sandwiched in the main direction (for example, the direction sandwiched between the right direction R and the upper right direction UR). It can be said that this method is suitable when emphasizing importance.

  Further, in the column (c), an example is illustrated in which the upper surface shapes of the cap member 12 and the plate-like member 130 are both circular. In such a combination, unlike the columns (a) and (b), it is not necessary to consider the relative relationship between the cap member 12 and the plate-like member 130 (the alignment of the apex position), and thus handling is easy. It becomes.

  Further, in the column (d), the upper surface of the cap member 12 is circular, and the upper surface of the plate member 130 is polygonal (in this case, a regular octagonal shape). With such a combination, the click feeling of the input operation can be clarified.

  The columns (a) to (d) are merely examples of combinations of the cap member 12 and the plate-like member 130. Various combinations other than the above (regular octagon + regular hexagon, A regular octagon + a circle or the like is possible, and an operational feeling corresponding to each combination is obtained. As described above, by arbitrarily combining the cap member 12 and the plate member 130, it is possible to appropriately transmit pressure from the plate member 130 to the pressure distribution sensor 1.

  Returning to FIG. 4, the description will be continued. The columnar member 140 is a member that is tilted up and down and left and right by a user's fingertip, and is attached to the plate-shaped member 130 so that a part thereof is exposed from the housing 110. Therefore, for example, when the columnar member 140 is tilted to the right in the drawing, the plate member 130 is also tilted to the right in the drawing, and when the columnar member 140 is tilted to the left in the drawing, the plate member 130 is also moved to the left in the drawing. Tilt to.

  Since the pressure distribution sensor 1 can be manufactured in a very small size (several mm square), it is difficult for the user to directly operate the pressure distribution sensor 1 with a fingertip. On the other hand, if the pressure distribution sensor 1 (chip size) is simply increased so as to easily accept the user's input operation, the yield and cost will increase.

  Therefore, the direction input device X1 of the present embodiment is provided with a pressure transmission mechanism (a plate member 130 and a columnar member 140) for generating a pressure distribution according to the user's input operation on the pressure distribution sensor 1. Yes. With this configuration, the pressure distribution sensor 1 can accept a user's input operation without causing an unnecessary increase in size of the pressure distribution sensor 1.

  FIG. 6 is a longitudinal sectional view showing a second embodiment of the direction input device X1. As in FIG. 4 above, column (a) indicates that no input operation has been performed on direction input device X1, and column (b) indicates that an input operation has been performed on direction input device X1 in the right direction on the page. The state (c) shows the state where the input operation in the left direction on the paper is being performed on the direction input device X1.

  The direction input device X1 of this embodiment is basically the same as that of the first embodiment (FIG. 4), but further includes an elastic member 150 that covers the pressure distribution sensor 1 and carries the plate member 130. doing. As a material of the elastic member 150, for example, silicon rubber can be suitably used. The plate member 130 is preferably formed in a cap shape by bending the outer edge end portion 130 so as not to be displaced in the horizontal direction on the upper surface of the elastic member 150. Further, when the thickness of the elastic member 150 sandwiched between the upper surface of the pressure distribution sensor 1 and the plate-like member 130 is t1, and the distance between the outer edge of the plate-like member 130 and the printed wiring board 120 is t2. , It is desirable to design each member so that t1≈t2.

  In the direction input device X1 of the present embodiment, it is possible to accept the user's input operation by the pressure distribution sensor 1 without causing an unnecessary increase in the size of the pressure distribution sensor 1, as in the first embodiment. Become. In addition, since the direction input device X1 of the present embodiment can flexibly receive the user's input operation via the elastic member 150, it provides a more comfortable operation feeling than the first embodiment. It becomes possible to do. In the direction input device X1 of the present embodiment, the wall portion 110b provided on the inner surface of the housing 110 can be omitted.

  FIG. 7 is a longitudinal sectional view showing a third embodiment of the direction input device X1. 4 and 6, the column (a) shows a state in which no input operation has been performed on the direction input device X1, and the column (b) shows an input operation in the right direction on the page of the direction input device X1. The state being performed, column (c) shows the state in which the input operation in the left direction on the paper is being performed on the direction input device X1.

  The direction input device X1 of this embodiment is basically the same as that of the first embodiment (FIG. 4), except that a projection 110c is provided on the bottom surface of the housing 110. The protrusion 110c is a hemispherical convex member formed so as to support the printed wiring board 120 at one point on the back side of the mounting position of the pressure distribution sensor 1.

  If the protrusion 110c supports the printed wiring board 120 at one point, the printed wiring board 120 is easily bent when the plate-like member 130 is tilted. Therefore, it becomes possible to detect the user's input operation more correctly.

  In this figure, the configuration based on the first embodiment (FIG. 4) is taken as an example, but it is also possible to add the protrusion 110c based on the second embodiment (FIG. 6). It is.

<Sensor chip and arithmetic processing chip>
FIG. 8 is a block diagram illustrating a configuration example of the sensor chip 10 and the arithmetic processing chip 20. The direction input device X1 of the present configuration example includes an arithmetic processing chip 20 in addition to the sensor chip 10 described above. The sensor chip 10 and the arithmetic processing chip 20 are preferably sealed in separate packages.

  In addition to the pressure-sensitive elements R1 to R8 arranged in a ring shape, the sensor chip 10 has eight pads (P12, P23, P34) as external terminals for drawing out connection nodes between the pressure-sensitive elements to the outside of the chip. , P45, P56, P67, P78, and P81). Specifically, the pad P12 is connected to a connection node between the pressure sensitive elements R1 and R2. The pad P23 is connected to a connection node between the pressure sensitive elements R2 and R3. The pad P34 is connected to a connection node between the pressure sensitive elements R3 and R4. The pad P45 is connected to a connection node between the pressure sensitive elements R4 and R5. The pad P56 is connected to a connection node between the pressure sensitive elements R5 and R6. The pad P67 is connected to a connection node between the pressure sensitive elements R6 and R7. The pad P78 is connected to a connection node between the pressure sensitive elements R7 and R8. The pad P81 is connected to a connection node between the pressure sensitive elements R8 and R1.

  The pressure sensitive elements R1 to R8 are preferably formed in the same shape. However, this does not exclude the case where each characteristic is unbalanced. Further, each of the pressure sensitive elements R1 to R8 may be formed by a single element or may be formed by a plurality of element elements. Since the pressure sensitive elements R1 to R8 are integrated in the single sensor chip 10, it is not necessary to consider each temperature characteristic variation.

  On the other hand, in the arithmetic processing chip 20, a pad switching unit 21, an output detection unit 22, and a logic unit 23 are integrated.

  The pad switching unit 21 switches the pad connection state of the sensor chip 10 so as to divide the eight pressure sensitive elements R1 to R8 into four pressure sensitive element groups Ra to Rd to form a bridge circuit. For example, the pad P12 is connected to the input terminal of the first power supply voltage VH (for example, VH = 2V), and the pad P56 is connected to the input terminal of the second power supply voltage VL (where VL <VH, for example, VL = 0V). When P34 is connected to the output terminal of the first output voltage V1 and the pad P78 is connected to the output terminal of the second output voltage V2, the pressure sensitive elements R2 and R3 correspond to the pressure sensitive element group Ra, and the pressure sensitive element The bridge circuit so that the elements R4 and R5 correspond to the pressure sensitive element group Rb, the pressure sensitive elements R6 and R7 correspond to the pressure sensitive element group Rc, and the pressure sensitive elements R8 and R1 correspond to the pressure sensitive element group Rd. Is formed. The pressure-sensitive element groups Ra to Rd are desirably designed so that the combined resistance values when no pressure is applied are the same (or substantially the same). However, in manufacturing, even if the resistance values of the pressure-sensitive element groups Ra to Rd are close to each other, it is difficult to make them completely the same value. Therefore, in reality, it is considered that the resistance values of the pressure sensitive element groups Ra to Rd when no pressure is applied are appropriately corrected outside the sensor chip 10. Examples of the correction value include a first correction value for correcting an error in a manufacturing stage and a second correction value for correcting a characteristic variation caused by subsequent use or environment.

  The output detection unit 22 is a circuit unit that detects the first output voltage V1 and the second output voltage V2 (corresponding to the output of the bridge circuit). As the output detection unit 22, for example, a differential amplifier that amplifies the difference between the first output voltage V1 and the second output voltage V2 can be used.

  The logic unit 23 receives the detection result of the output detection unit 22 and determines the user's input operation. Note that the input operation determination method of the logic unit 23 will be described in detail later.

<Pad switching control>
FIG. 9 is a table showing a first example of pad switching control by the pad switching unit 21. The pad switching unit 21 sequentially switches the division pattern of the pressure-sensitive element groups Ra to Rd over the first switching phase SW1 to the fourth switching phase SW4 by the following pad switching control.

  In the first switching phase SW1, the pad P12 is connected to the input terminal of the first power supply voltage VH, the pad P34 is connected to the output terminal of the first output voltage V1, and the pad P56 is connected to the input terminal of the second power supply voltage VL. The pad P78 is connected to the output terminal of the second output voltage V2. The remaining pads (P23, P45, P67, P81) are all open. With such pad switching control, in the first switching phase SW1, the pressure sensitive elements R2 and R3 correspond to the pressure sensitive element group Ra, the pressure sensitive elements R4 and R5 correspond to the pressure sensitive element group Rb, and the pressure sensitive element The bridge circuit is formed such that R6 and R7 correspond to the pressure sensitive element group Rc, and the pressure sensitive elements R8 and R1 correspond to the pressure sensitive element group Rd.

  In the second switching phase SW2, the pad P23 is connected to the input terminal of the first power supply voltage VH, the pad P45 is connected to the output terminal of the first output voltage V1, and the pad P67 is connected to the input terminal of the second power supply voltage VL. The pad P81 is connected to the output terminal of the second output voltage V2. The remaining pads (P12, P34, P56, P78) are all open. By such pad switching control, in the second switching phase SW2, the pressure sensitive elements R3 and R4 correspond to the pressure sensitive element group Ra, the pressure sensitive elements R5 and R6 correspond to the pressure sensitive element group Rb, and the pressure sensitive element. The bridge circuit is formed such that R7 and R8 correspond to the pressure sensitive element group Rc, and the pressure sensitive elements R1 and R2 correspond to the pressure sensitive element group Rd.

  In the third switching phase SW3, the pad P34 is connected to the input terminal of the first power supply voltage VH, the pad P56 is connected to the output terminal of the first output voltage V1, and the pad P78 is connected to the input terminal of the second power supply voltage VL. Then, the pad P12 is connected to the output terminal of the second output voltage V2. The remaining pads (P23, P45, P67, P81) are all open. By such pad switching control, in the third switching phase SW3, the pressure sensitive elements R4 and R5 correspond to the pressure sensitive element group Ra, the pressure sensitive elements R6 and R7 correspond to the pressure sensitive element group Rb, and the pressure sensitive element The bridge circuit is formed such that R8 and R1 correspond to the pressure sensitive element group Rc, and the pressure sensitive elements R2 and R3 correspond to the pressure sensitive element group Rd.

  In the fourth switching phase SW4, the pad P45 is connected to the input terminal of the first power supply voltage VH, the pad P67 is connected to the output terminal of the first output voltage V1, and the pad P81 is connected to the input terminal of the second power supply voltage VL. The pad P23 is connected to the output terminal of the second output voltage V2. The remaining pads (P12, P34, P56, P78) are all open. By such pad switching control, in the fourth switching phase SW4, the pressure sensitive elements R5 and R6 correspond to the pressure sensitive element group Ra, the pressure sensitive elements R7 and R8 correspond to the pressure sensitive element group Rb, and the pressure sensitive element The bridge circuit is formed such that R1 and R2 correspond to the pressure sensitive element group Rc, and the pressure sensitive elements R3 and R4 correspond to the pressure sensitive element group Rd.

  FIG. 10 is a table showing a second example of pad switching control. The pad switching control of this example is basically the same as that of the first example (FIG. 9), but the pad switching unit 21 is provided for each of the first switching phase SW1 to the fourth switching phase SW4 (by extension, The first output terminal and the second output terminal of the bridge circuit are inverted with respect to each other (for each divided pattern of the pressure sensitive element groups Ra to Rd).

  For example, consider the case where the pad P34 is connected to the output terminal of the first output voltage V1 and the pad P78 is connected to the output terminal of the second output voltage V2 in the first switching phase SW1. Here, when the voltage appearing at the pad P34 is V34, the voltage appearing at the pad P78 is V78, and the input offset of the differential amplifier used as the output detection unit 22 is Vofs, the output signal OUT1 of the output detection unit 22 is (1).

OUT1 = (V1-V2) + Vofs
= (V34-V78) + Vofs (1)

  On the other hand, in the same first switching phase SW1, when the pad P78 is connected to the output terminal of the first output voltage V1 and the pad P34 is connected to the output terminal of the second output voltage V2, that is, the first output voltage V1 and the first output voltage V1. Consider a case where the positive and negative polarities of the two output voltages V2 are mutually inverted. At this time, the output signal OUT2 of the output detection unit 22 can be expressed by the following equation (2).

OUT2 = (V1-V2) + Vofs
= (V78−V34) + Vofs (2)

  As can be seen from the above equations (1) and (2), the output signals OUT1 and OUT2 each include the input offset Vofs of the differential amplifier, which causes a deterioration in the detection accuracy of the sensor output. .

  Therefore, the logic unit 23 calculates the output signal OUT3 by subtracting the output signal OUT2 from the output signal OUT1, and determines the user's input operation based on the calculation result. The output signal OUT3 can be expressed by the following equation (3).

OUT3 = OUT1-OUT2
= {(V78−V34) + Vofs} − {(V34−V78) + Vofs}
= 2 × (V78−V34) (3)

  As can be seen from the above equation (3), since the output signal OUT3 does not include the input offset Vofs of the differential amplifier, the detection accuracy of the sensor output can be increased.

  It should be noted that the same effects as described above can be obtained by performing the same positive / negative inversion processing as described above for the second switching phase SW2 to the fourth switching phase SW4.

<Input operation determination method>
Next, a method for determining an input operation in the logic unit 23 will be specifically described with reference to FIGS. 8 to 9 as appropriate. In the following description, it is assumed that the first power supply voltage VH is 2V, the second power supply voltage VL is 0V, and the resistance values of the pressure sensitive elements R1 to R8 to which no stress is applied are all 100Ω. I do.

  When no stress is applied to the pressure sensitive elements R1 to R8, or when stress is equally applied to the pressure sensitive elements R1 to R8, the first switching phase SW1 is used. The 1 output voltage V1 and the 2nd output voltage can be expressed by the following equations (4) and (5), respectively.

V1 = VL + (VH−VL) × {(R4 + R5) / (R2 + R3 + R4 + R5)}
= 1V (4)

V2 = VL + (VH−VL) × {(R6 + R7) / (R6 + R7 + R8 + R1)}
= 1V (5)

  Similarly to the above, when no stress is applied to the pressure sensitive elements R1 to R8, or when stress is equally applied to the pressure sensitive elements R1 to R8, the second switching phases SW2 to SW2 are applied. The first output voltage V1 and the second output voltage V2 obtained in the fourth switching phase SW4 are both 1V.

  Thus, in the detection results of the first switching phase SW1 to the fourth switching phase SW4, when the first output voltage V1 and the second output voltage V2 all show the same voltage value (VH + VL) / 2, R1 It can be seen that = R2 = R3 = R4 = R5 = R6 = R7 = R8. As a result, it can be seen that each of the pressure sensitive elements R1 to R8 is not subjected to stress, or all exhibit the same resistance value as a result of being equally stressed.

  Here, for example, when the current value flowing from the pad P12 to the pad P56 in the first switching phase SW1 is 10 mA, the combined resistance value between the two pads is calculated to be 200Ω. Therefore, since the resistance values of the pressure sensitive elements R1 to R8 are calculated to be 100Ω, respectively, it can be seen that none of the pressure sensitive elements R1 to R8 were in a state of receiving stress.

  On the other hand, for example, when the current value flowing from the pad P12 to the pad P56 in the first switching phase SW1 is 12.5 mA, the combined resistance value between the two pads is calculated to be 160Ω. Accordingly, since the resistance values of the pressure sensitive elements R1 to R8 are calculated to be 80Ω, respectively, the pressure sensitive elements R1 to R8 are evenly subjected to a stress that changes the resistance values from 100Ω to 80Ω. It turns out that it was in a state.

  Next, a case where stress is applied in the right direction R from the center portion of the sensor chip 10 will be described. In this case, the sensor chip 10 is most distorted in the vicinity of the pressure sensitive element R8, and the next distortion is in the vicinity of the pressure sensitive elements R1 and R7. As a result, for example, the resistance value of the pressure-sensitive element R8 changes from 100Ω to 80Ω, the resistance values of the pressure-sensitive elements R1 and R7 change from 100Ω to 90Ω, respectively, and the resistance of the remaining pressure-sensitive elements R2 to R6 All values are assumed to be maintained at 100Ω.

  In the first switching phase SW1, the first output voltage V1 obtained at the pad P34 is 1V (= 2V × 100Ω / 200Ω). Therefore, it can be seen that the ratio of the combined resistance value of the pressure sensitive element group Ra (= R2 + R3) and the combined resistance value of the pressure sensitive element group Rb (= R4 + R5) is 1: 1. In the first switching phase SW1, the second output voltage V2 obtained at the pad P78 is 1.06V (= 2V × 190Ω / 360Ω). Therefore, it can be seen that the ratio of the combined resistance value of the pressure-sensitive element group Rc (= R6 + R7) and the combined resistance value of the pressure-sensitive element group Rd (= R8 + R1) is 19:17.

  In the second switching phase SW2, the first output voltage V1 obtained at the pad P45 is 1V (= 2V × 100Ω / 200Ω). Therefore, it can be seen that the ratio of the combined resistance value of the pressure-sensitive element group Ra (= R3 + R4) and the combined resistance value of the pressure-sensitive element group Rb (= R5 + R6) is 1: 1. In the second switching phase SW2, the second output voltage V2 obtained at the pad P81 is 0.94 V (= 2V × 170Ω / 360Ω). Therefore, it can be seen that the ratio of the combined resistance value of the pressure-sensitive element group Rc (= R7 + R8) and the combined resistance value of the pressure-sensitive element group Rd (= R1 + R2) is 17:19.

  In the third switching phase SW3, the first output voltage V1 obtained at the pad P56 is 0.97V (= 2V × 190Ω / 390Ω). Therefore, it can be seen that the ratio of the combined resistance value of the pressure-sensitive element group Ra (= R4 + R5) and the combined resistance value of the pressure-sensitive element group Rb (= R6 + R7) is 20:19. In the third switching phase SW3, the second output voltage V2 obtained at the pad P12 is 0.92V (= 2V × 170Ω / 370Ω). Therefore, it can be seen that the ratio of the combined resistance value of the pressure-sensitive element group Rc (= R8 + R1) and the combined resistance value of the pressure-sensitive element group Rd (= R2 + R3) is 17:20.

  In the fourth switching phase SW4, the first output voltage V1 obtained at the pad P67 is 0.92V (= 2V × 170Ω / 370Ω). Therefore, it can be seen that the ratio of the combined resistance value of the pressure-sensitive element group Ra (= R5 + R6) and the combined resistance value of the pressure-sensitive element group Rb (= R7 + R8) is 20:17. In the fourth switching phase SW4, the second output voltage V2 obtained at the pad P23 is 0.97 V (= 2V × 190Ω / 390Ω). Therefore, it can be seen that the ratio of the combined resistance value of the pressure-sensitive element group Rc (= R1 + R2) to the combined resistance value of the pressure-sensitive element group Rd (= R3 + R4) is 19:20.

  When calculation is performed based on these detection results, R1: R2: R3: R4: R5: R6: R7: R8 = 0.9: 1: 1: 1: 1: 1: 1: 0.9: 0.8 A resistance ratio is derived. From this resistance ratio, it can be seen that the strongest stress is applied to the pressure sensitive element R8, and then the next stress is applied to the pressure sensitive elements R1 and R7 located at both ends of the pressure sensitive element R8. . As a result, the logic unit 23 can determine that stress is applied in the right direction R from the center of the sensor chip 10.

  As a similar example, when a resistance ratio of R1: R2: R3: R4: R5: R6: R7: R8 = 0.95: 1: 1: 1: 1: 1: 0.95: 0.9 is derived. It can be determined that a stress that is weaker than that in the above example is applied in the right direction R from the center of the sensor chip 10. Conversely, when a resistance ratio of R1: R2: R3: R4: R5: R6: R7: R8 = 0.85: 1: 1: 1: 1: 1: 0.85: 0.7 is derived It can be determined that a stress stronger than that in the above example is applied in the right direction R from the center of the sensor chip 10.

  In the above description, the case where stress is applied in the right direction R from the center of the sensor chip 10 has been described as an example. However, the same applies to the case where stress is applied in other directions. By calculating the resistance ratio, it is possible to determine the content of the input operation.

  In the above description, for example, in the first switching phase SW1, the voltages appearing on the pads P34 and P78 are measured. However, if the voltages appearing on the other pads (P23, P45, P67, P81) are measured, The final result can be obtained with a small number of measurements.

  Further, even when the stress distribution is biased and the direction in which the external stress is applied from the center of the sensor chip 10 can be detected, as described above, when the overall resistance value is changing as a whole, Further, it can be determined that the stress is also applied to the whole in the direction perpendicular to the plane on which the pressure sensitive element is formed.

<Modification of output detection method>
FIG. 11 is a schematic diagram illustrating a modification of the output detection method. The pressure distribution sensor 200 of this modification has a constant current circuit 220 and a current detection circuit 230 in addition to the bridge circuit 200 formed by the four pressure sensitive element groups Ra to Rd.

  The pressure sensitive element groups Ra to Rd are obtained by dividing the aforementioned pressure sensitive elements R1 to R8 into four groups. The pad Pa is connected to a connection node between the pressure-sensitive element group Rd and the pressure-sensitive element group Ra. For example, in the first switching phase SW1 described above, the pad P12 corresponds to this. The pad Pb is connected to a connection node between the pressure-sensitive element group Ra and the pressure-sensitive element group Rb. For example, in the first switching phase SW1 described above, the pad P34 corresponds to this. The pad Pc is connected to a connection node between the pressure-sensitive element group Rb and the pressure-sensitive element group Rc. For example, in the first switching phase SW1 described above, the pad P56 corresponds to this. The pad Pd is connected to a connection node between the pressure-sensitive element group Rc and the pressure-sensitive element group Rd. For example, in the first switching phase SW1 described above, the pad P78 corresponds to this.

  The constant current circuit 220 generates a constant current that flows from the pad Pa to the pad Pc.

  The current detection circuit 230 detects a current flowing between the pad Pb and the pad Pd.

  In the output detection method described above, the voltage appearing at each of the pads Pb and Pd is measured in a state where the first power supply voltage VH is applied to the pad Pa and the second power supply voltage VL is applied to the pad Pc. On the other hand, as in the output detection method of this modification, for example, the voltage appearing at each of the pads Pb and Pd is measured in a state where a constant current is passed from the pad Pa to the pad Pc, or It is also possible to derive the resistance ratio of each pressure sensitive element by measuring the current flowing between it and the pad Pd.

<Modification of sensor chip>
FIG. 12 is a schematic diagram illustrating a modified example of the sensor chip 10. In the above configuration (see FIGS. 2, 3, 8, etc.), the pressure sensitive elements R1 to R8 are formed in an annular shape so that the longitudinal direction and the arrangement direction thereof coincide with each other. However, the form of the pressure sensitive elements R1 to R8 is not limited to this. For example, as shown in the modification of the column (a), each of the pressure sensitive elements R1 to R8 is provided on the sensor chip 10. The longitudinal direction may be formed radially toward the center of the sensor chip 10. That is, the longitudinal direction and the arrangement direction of the pressure sensitive elements R1 to R8 do not have to coincide with each other.

  Further, in the above configuration (see FIGS. 2, 3, and 8), the sensor chip 10 has each pressure-sensitive element in order to reduce the number of external terminals and reduce the measurement error of the pressure distribution. A structure having a plurality of pads (P12, P23, P34, P45, P56, P67, P78, and P81) for connecting each other by wiring and for drawing out a connection node between each pressure sensitive element to the outside of the chip. It was said.

  However, the form of the sensor chip 10 is not limited to this. For example, as shown in the modified example in the column (b), the sensor chip 10 has both end nodes for each pressure-sensitive element independently on the outside of the chip. As a form having a plurality of pads P * a and P * b (* = 1, 2,..., 8) to be drawn out, and optionally connecting each pad outside the sensor chip 10 as necessary. Also good.

<Sensor chip that does not require a cap member>
FIG. 13 is a schematic diagram illustrating a configuration example of the sensor chip 10 that does not require the cap member 12. As described above, in the sensor chip 10 cut out in a square shape, the four apexes (a2, a4, a6, a8) farthest from the center point O are the points (stresses) that are most strongly subjected to bending pressure / strain. Concentration point).

  Therefore, if all the pressure sensitive elements R1 to R8 are provided at a position equidistant from the center point O of the sensor chip 10, the center point O and the four vertices (a2, a4, a6, The pressure sensitive elements (R2, R4, R6, R8) provided on the line segment connecting to a8) pass through other positions (for example, the center point O of the sensor chip 10 and on the four sides of the sensor chip 10). The sensitivity is higher than that of the pressure sensitive elements (R1, R3, R5, R7) provided on the vertical straight line.

  In the previous example, the sensitivity of each of the pressure sensitive elements R1 to R8 is made uniform by covering the sensor IC 11 with the cap member 12. On the other hand, in the sensor chip 10 of the present configuration example, the distance dx from the pressure sensitive element (R2, R4, R6, R8) to the center point O and the pressure sensitive element (R1, R3, R5, R7) to the center point O. By making a difference from the distance dy, the sensitivity of each of the pressure sensitive elements R1 to R8 is made uniform. Specifically, in view of the fact that the sensitivity decreases as the pressure sensitive elements R1 to R8 are brought closer to the center point O (the pressure sensitive elements R1 to R8 are less likely to be distorted), the pressure sensitive element R1 is set so that dx <dy. -R8 is arranged.

  Thus, by multiplying the sensitivity difference caused by the stress concentration on the sensor chip 10 by the sensitivity difference according to the distance from the center point O, the pressure sensitive elements R1 to R1 are not required without the cap member 12. It becomes possible to equalize the sensitivity for each R8. However, the cap member 12 also has a function of preventing the operation feeling in each input direction from changing when the user operates the direction input device X1 (ie, avoiding jerking). Therefore, when the smooth operation feeling is important, it is desirable to put the cap member 12 on the sensor chip 11.

  In addition, even when the sensor chip does not employ the above-described pressure-sensitive element arrangement method, after assembling the direction input device using the sensor chip, the sensor output values when equal pressure is applied in each direction are compared. In the above, sensitivity correction values may be obtained so as to be equal to each other and stored in the nonvolatile memory. When the direction input device is actually used, the apparent sensitivity can be made uniform by correcting the sensor output value using the sensitivity correction value.

<Modification of plate member>
FIG. 14 is a longitudinal sectional view showing a modification of the plate member 130. In FIG. 7, the printed wiring board 120 is placed on the back surface side (lower surface side) of the printed wiring board 120 immediately below the center point of the pressure distribution sensor 1 (and thus just below the center point of the sensor chip 10). The structure which provided the protrusion part 110c which supports one point was proposed. As described above, the advantage of adopting such a structure can promote deformation of the sensor chip 10 due to pressure.

  In order to enjoy the same advantages as described above, it is also effective to provide a recess 130a on the back surface (the surface facing the pressure distribution sensor 1) of the plate member 130, as shown in the figure. In addition, about the projection part 110c of the housing | casing 110 and the recessed part 130a of the plate-shaped member 130, both may be used or each may be used independently.

<Application example of biasing member>
FIG. 15 is a diagram illustrating an application example of the urging member 160. A top view of the urging member 160 is depicted on the upper stage, and a longitudinal sectional view (α1-α2 sectional view) of the urging member 160 is depicted on the lower stage.

  The urging member 160 is a member for generating a pressure distribution according to a user's direction input operation on the upper surface of the package of the sensor IC 11, and can be used in place of the above-described plate-shaped member 130. The urging member 160 of the present configuration example has a chrysanthemum shape composed of a plurality (eight in this figure) of leaf spring portions 160a and a connecting portion 160b.

  The plate spring portion 160a has a trapezoidal shape (or a triangular shape) that becomes narrower toward the tip when viewed from above, and is arranged so that the tip faces the package top surface of the sensor IC 11. The tip of the leaf spring 160a is bent downward toward the upper surface of the sensor IC 11 package. That is, pressure is applied to the upper surface of the package of the sensor IC 11 by bending the leaf spring portion 160a.

  The connecting portion 160b connects the base ends in an annular shape so that the leaf spring portions 160a are arranged radially with the sensor IC 11 as the center. The connecting portion 160b is fixed to the printed wiring board 120 together with the sensor IC 11.

  In processing the urging member 160, for example, a plurality of leaf spring portions 160a and connecting portions 160b can be integrally formed by punching a single metal plate.

  FIG. 16 is a diagram showing a cross-sectional shape of the columnar member 140 suitable for pressure transmission to the urging member 160. A top view of the urging member 160 is depicted in the upper stage, and a longitudinal sectional view (α1-α2 sectional view) of the urging member 160 and the columnar member 140 is depicted in the lower stage.

  The columnar member 140 is a member that bends the plurality of leaf spring portions 160a in response to a user's direction input operation, and includes a contact portion 140a and a locking portion 140b.

  The abutting portion 140a is provided on the lower surface of the central portion of the columnar member 140 (the surface facing the biasing member 160), and is inclined so as to abut each of the plurality of leaf spring portions 160a in the vicinity of each tip. It is processed into a shape with a concave shape (concave shape with a depressed central portion).

  The locking portion 140b comes into contact with the housing 110 and the printed wiring board 120 when the user performs a direction input operation. By setting it as such a structure, it becomes possible to give the upper limit to the inclination amount of the columnar member 140, and to suppress the deviation | shift in the front-back and left-right direction. Further, by providing the locking portion 140b, it is possible to prevent the columnar member 140 from coming off the housing 110 upward.

  For example, when the user performs a direction input operation, the columnar member 140 is tilted, so that the leaf spring portion 160a corresponding to the tilt direction is bent. As a result, on the upper surface of the package of the sensor IC 11, the peripheral portion corresponding to the user's operation direction is pressed by the tip of the leaf spring portion 160 a, so that a pressure distribution according to the user's direction input operation occurs. According to such a configuration, the above-described cap member 12 becomes unnecessary.

  Note that the bottom portion of the housing 110 supports the printed wiring board 120 at the periphery thereof and directly below the sensor IC 11. On the other hand, at the bottom of the housing 110, a portion where the printed wiring board 120 is expected to be bent is subjected to a punching process (= processing provided with an unsupported portion of the printed wiring board 120).

<Other variations>
The various technical features disclosed in the present specification can be variously modified within the scope of the technical creation in addition to the above-described embodiment. That is, the above-described embodiment is to be considered in all respects as illustrative and not restrictive, and the technical scope of the present invention is indicated not by the description of the above-described embodiment but by the scope of the claims. It should be understood that all modifications that fall within the meaning and range equivalent to the terms of the claims are included.

  The pressure distribution sensor disclosed in the present specification can be used for a controller of a game machine, for example.

X Electronic equipment (game equipment)
X1 direction input device (cross key)
X2 button X3 display screen 1 Pressure distribution sensor 10 Sensor chip 11 Sensor IC
DESCRIPTION OF SYMBOLS 12 Cap member 20 Arithmetic processing chip 21 Pad switching part 22 Output detection part 23 Logic part 110 Case 110a Support part 110b Wall part 110c Protrusion part 120 Printed wiring board 130 Plate-shaped member 130a Recessed part 140 Columnar member 140a Contact part 140b Locking Part 150 Elastic member 160 Biasing member 160a Leaf spring part 160b Connection part 200 Pressure distribution sensor 210 Bridge circuit 220 Constant current circuit 230 Current detection circuit R1 to R8 Pressure sensing element Ra to Rd Pressure sensing element group P12, P23, P34, P45 , P56, P67, P78, P81 Pad P * a, P * b (where * = 1, 2,..., 8) Pad

Claims (36)

A sensor IC in which m (where m is an integer of 4 or more) pressure-sensitive elements are sealed in a package whose upper surface is a quadrangular shape;
A cap member that has an n-side top surface (where n is an integer greater than 4) or a circular shape and covers the sensor IC so as to be in close contact with the top surface and side surfaces of the sensor IC;
A pressure distribution sensor comprising:   2. The pressure distribution sensor according to claim 1, wherein each of the m and the n is a multiple of 4 that is 8 or more.   The said cap member is covered with the said sensor IC so that four vertices among the n vertices may be located on the straight line which ties the diagonals of the said sensor IC, The Claim 1 or Claim 2 characterized by the above-mentioned. The described pressure distribution sensor.   The pressure distribution sensor according to any one of claims 1 to 3, wherein the pressure distribution sensor is mounted on a printed wiring board so that the four vertices correspond to the vertical and horizontal directions, respectively.   The pressure distribution sensor according to any one of claims 1 to 4, wherein the m pressure sensitive elements are integrated in a single sensor chip.   The pressure distribution sensor according to claim 5, wherein the m pressure-sensitive elements are all formed in the same shape.   The m pressure sensitive elements are annularly arranged on the sensor chip so that four of them are located on a line segment connecting the center point of the sensor chip and the four vertices of the sensor chip. The pressure distribution sensor according to claim 5 or 6.   The m pressure-sensitive elements are formed on the sensor chip in a radial manner with their longitudinal directions directed toward the center of the sensor chip. The pressure distribution sensor described in 1.   The pressure distribution sensor according to any one of claims 5 to 8, wherein the sensor chip has a plurality of pads for pulling out connection nodes between the pressure sensitive elements to the outside of the chip. .   The pressure distribution sensor according to any one of claims 5 to 8, wherein the sensor chip has a plurality of pads for drawing out both end nodes of each pressure sensitive element to the outside of the chip. A housing,
A printed wiring board supported by the housing;
The pressure distribution sensor according to any one of claims 1 to 10, which is mounted on the printed wiring board,
A plate-like member placed on the upper surface of the pressure distribution sensor so as to incline in a direction according to a user's direction input operation;
An input device comprising:   The input device according to claim 11, wherein the upper surface of the plate-like member has a shape obtained by enlarging the upper surface of the pressure distribution sensor.   The amount of inclination of the plate-like member is limited by the outer edge of the plate member being in contact with the casing, the printed wiring board, or the contact member. Input device.   The input device according to claim 11, further comprising an elastic member that covers the pressure distribution sensor and supports the plate-like member.   The input according to any one of claims 11 to 14, wherein the casing includes a protrusion that supports the printed wiring board at one point on the back side of the mounting position of the pressure distribution sensor. apparatus. A pad switching unit that switches the pad connection state of the sensor chip so as to divide the m pressure sensitive elements into four pressure sensitive element groups to form a bridge circuit;
An output detector for detecting the output of the bridge circuit;
A logic unit that receives a detection result of the output detection unit to determine a user's input operation;
The input device according to claim 11, further comprising:   The input device according to claim 16, wherein the pressure-sensitive element groups are designed such that the combined resistance values when no pressure is applied are the same.   The input device according to claim 16 or 17, wherein the pad switching unit sequentially switches a division pattern of the pressure-sensitive element group.   The input device according to claim 18, wherein the pad switching unit inverts the first output terminal and the second output terminal of the bridge circuit to each other for each division pattern of the pressure-sensitive element group.   An electronic apparatus comprising the input device according to any one of claims 11 to 19. A sensor IC that detects the distribution of pressure applied to a package whose upper surface is a quadrangular shape;
A cap member that has an n-sided top surface (where n is a multiple of 4 greater than 8) and covers the sensor IC so as to be in close contact with the top and side surfaces of the sensor IC;
Have
The pressure distribution sensor, wherein the cap member is placed on the sensor IC such that four of the n vertices are positioned on a straight line connecting diagonals of the sensor IC. a pressure distribution sensor including m pressure sensors (where m is a multiple of 4 that is greater than or equal to 8);
A pad switching unit that switches the pad connection state of the sensor chip so as to divide the m pressure sensitive elements into four pressure sensitive element groups to form a bridge circuit;
An output detector for detecting the output of the bridge circuit;
A logic unit that receives a detection result of the output detection unit to determine a user's input operation;
An input device comprising: A square sensor chip formed by integrating a plurality of pressure sensitive elements,
The pressure-sensitive element arranged on the line segment connecting the center point of the sensor chip and the four vertices is provided closer to the center point than the pressure-sensitive elements arranged at other positions. Sensor chip.   The pressure according to any one of claims 5 to 8, wherein the m pressure-sensitive elements are provided in an annular shape at substantially equal intervals around a center point of the sensor chip. Distribution sensor.   In the sensor IC, the upper surface of the package has a square shape, and the four vertices of the package are located on the extension line of the line connecting the center point of the sensor chip and the four vertices of the sensor chip. The pressure distribution sensor according to any one of claims 5 to 8.   The upper surface of the cap member has an n-corner shape, and four vertices among the n vertices of the cap member are located on an extension line of a line segment connecting the center point of the sensor chip and the four vertexes of the sensor chip. The pressure distribution sensor according to any one of claims 5 to 8, wherein the pressure distribution sensor is provided.   The upper surface of the cap member has an m-corner shape, and the m apex of the cap member is located on an extension of a line segment that connects the center point of the sensor chip and the m pressure sensitive elements. The pressure distribution sensor according to any one of claims 5 to 8, wherein:   The input device according to claim 11, wherein the upper surface of the plate-like member has an n-corner shape or a polygonal shape.   The upper surface of each of the pressure distribution sensor and the plate-like member has an n-corner shape, and the apex of the pressure distribution sensor and the apex of the plate-like member are each 360 / 2n degrees in a top view. The input device according to claim 11, wherein the input device is directed in a shifted direction.   The input device according to claim 11, wherein an upper surface of the pressure distribution sensor has an n-shaped shape, and an upper surface of the plate-like member has a circular shape.   The input device according to claim 11, wherein the plate-like member includes a concave portion on a surface facing the pressure distribution sensor. A sensor IC for detecting the distribution of pressure applied to the upper surface of the package;
An urging member for generating a pressure distribution according to a user's direction input operation on the upper surface of the package of the sensor IC;
Have
The biasing member is
A plurality of leaf spring portions each having a tip opposed to the upper surface of the package of the sensor IC;
A connecting portion that connects the base ends in a ring shape so that the leaf spring portions are arranged radially around the sensor IC;
An input device comprising:   The input device according to claim 32, wherein the connecting portion is fixed to a printed wiring board together with the sensor IC.   The input device according to claim 32 or 33, wherein each of the plurality of leaf spring portions is bent toward an upper surface of a package of the sensor IC.   The input device according to any one of claims 32 to 34, wherein each of the plurality of leaf springs has a trapezoidal shape that becomes narrower at a tip end.   36. The input device according to any one of claims 32 to 35, further comprising a columnar member that bends the plurality of leaf spring portions in response to a user's direction input operation.

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