JP3039286B2 - Load sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load sensor used for a pointing device for inputting two-dimensional coordinates.

[0002]

2. Description of the Related Art In recent years, a pointing device is an important input as a two-dimensional coordinate input and an operation input device of a GUI (graphical user interface) such as a personal computer (hereinafter referred to as a "personal computer"). It is attracting attention. As personal computers have become smaller and lighter, notebook personal computers have been widely used, and a "mouse" has been widely used as one of such pointing devices. However, notebook computers are not only on desks,
The use of the mouse in places where it is not possible to secure a flat surface for operating the mouse, such as placing it on the lap or operating a mouse such as a train or airplane, has increased, and the mouse has become a pointing device with a problem in use. In order to solve the problem, a pointing device using a load sensor has been developed.

[0003] A pointing device using a conventional load sensor will be described below. FIG. 12 is a perspective view of a pointing device using a conventional load sensor. In FIG. 12, reference numeral 41 denotes a mounting base. Reference numeral 42 denotes a quadrangular prism-shaped shaft integrally provided at the center of the mounting table 41.
The upper surface has an operation unit 43 for applying a load with a finger. The side surface of the shaft 42 has two pairs of first and second strain gauges 44, 44 ′, and 4 that are attached so as to form a pair with the facing surface.
5, 45 ', and the shaft 4
The shaft 42 is deformed by a component force perpendicular to the axis 2, and the first and second strain gauges 44, 44 ', 45, 45
'Contracts and the resistance value changes.

That is, the first and second strain gauges 44, 4
4 ′, 45, and 45 ′ are a pair of one set symmetrical with the center axis of the shaft 42, and the two pairs of the first and second strain gauges 4.
4, 44 ', 45, 45' are arranged at 90 ° intervals, so that the deformation of the shaft 42 can be divided into two coordinates. Actually, a signal obtained by taking the difference between the signals of the pair of strain gauges composed of the first strain gauges 44, 44 'is defined as a signal in the direction of one coordinate axis, and the signals of the second strain gauges 45, 45' are similarly represented. Is taken as a signal for the other coordinate axes.

Based on the signals of the two coordinate axes, the direction and magnitude of the force applied by the finger to the operation unit 43 are detected, and the CRT is used.
It is a signal to move the pointer above (not shown).

[0006]

In the above-mentioned conventional configuration,
The first and second strain gauges 44, 44 ', 45,
Since the position of the adhesive 45 'is bonded, if the bonding position is shifted, the sensitivity to the force applied to the operation unit 43 on the upper surface of the shaft 42 changes, and the moving direction of the pointer changes. There was a problem that sometimes it was necessary to take a bonding method so as not to deform the first and second strain gauges 44, 44 ', 45, 45'.

Furthermore, the resistance values of the first and second strain gauges 44, 44 ', 45, 45' on the opposite side surfaces of the shaft 42 need to be the same, and they must be selectively used. Therefore, there has been a problem that the cost is increased and the assembly is complicated.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a low-cost load sensor excellent in mass productivity.

[0009]

In order to solve the above-mentioned conventional problems, a load sensor according to the present invention comprises an L-shaped or T-shaped load sensor .
An elastic plate and a glass enamel coating provided on the elastic plate
A cover layer, an operation unit connected to the center of the elastic plate,
The center of the elastic plate can be rotated and perpendicular to the plane of the elastic plate
Direction is supported by the pivot support so as to be regulated.
And fix two places around the elastic plate with fixing parts
Mounting plate and thick film printing on the glass enamel coating layer
And two strain-sensitive resistors formed directly by
Things.

[0010]

According to the above construction, L-shaped or T-shaped elasticity is obtained.
For thick film printing on the glass enamel coating layer provided on the plate
Since two more strain-sensitive resistors are formed directly, there is no displacement due to bonding unlike the conventional technology, and the strain-sensitive resistors can be arranged collectively and accurately. In addition, it is possible to obtain a material having a high relative accuracy of the resistance value, and it is also easy to perform the trimming, so that the resistance value can be made more accurate. Further, by providing the glass enamel coating layer on the elastic plate, a metal glaze resistor that can be processed at a high temperature and has high reliability can be used as the strain sensitive resistor. And also elastic plate
Pivot support of the mounting base fixed at two places around the
The center of the elastic plate can be rotated by the
Supports movement in the vertical direction with respect to the plane
Therefore, only horizontal load can be detected accurately,
As a result, a load sensor with excellent operability can be obtained.
It is.

[0011]

Embodiment (Embodiment 1) Hereinafter, a pointing device using a load sensor according to an embodiment of the present invention will be described.

FIG. 1 is a perspective view of a pointing device using a load sensor according to an embodiment of the present invention.
In FIG. 1, reference numeral 1 denotes an elastic plate, a substrate made of a piezoelectric material,
It is made of any one of a metal plate coated at least partially with an electrically insulating material of glass or resin, an enameled metal plate, a substrate made of alumina, a substrate made of a resin material, or a copper-clad laminate. Reference numeral 2 denotes an operation unit provided substantially at the center of the elastic plate 1 so as to be connected to the elastic plate 1. Reference numeral 3 denotes a mounting table. The mounting table 3 has four ends around the elastic plate 1 fixed by fixing portions 4. The elastic plate 1 is deformed by applying a force to the operating portion 2 with a finger. It has a structure. Between the operation unit 2 and the fixed unit 4 on the elastic plate 1,
First and second strain sensitive resistors having the same resistance value are provided at positions facing the operation unit 2, that is, symmetrical positions orthogonal to a line connecting the fixing unit 4 and the operation unit 2 on the same surface of the elastic plate 1. Are provided.

The operation of the pointing device using the load sensor according to one embodiment of the present invention configured as described above will be described below.

First, when a force is applied to the operation unit 2 in the direction "A" parallel to the elastic plate 1 shown in FIG. 1, the first strain resistance detecting element 5 of the elastic plate 1 has a concave surface and The portion of the first strain resistance detecting element 5 'is deformed into a convex surface. Due to this deformation, the resistance value of the first strain resistance detection element 5 decreases and the resistance value of the first strain resistance detection element 5 'increases. By calculating the difference between the change in the resistance value of the pair of first strain resistance detecting elements 5 and 5 ', the change in the resistance value is doubled, and the applied force can be detected.

On the other hand, the second strain resistance detecting elements 6, 6 '
Does not change the resistance value only by applying a torsional stress in the same direction. That is, the first strain resistance detecting element 5,
The force only in the coordinate axis direction on 5 'can be detected.

Next, when a force is applied to the operation unit 2 in the direction "A" parallel to the elastic plate 1 shown in FIG. 1, the portion of the elastic plate 1 where the second strain resistance detecting element 6 is formed is concave. In addition, the portion of the second strain resistance detecting element 6 'is deformed into a convex
Since only the torsional stress in the same direction is applied to the strain resistance detecting elements 5 and 5 ′, the force in only the coordinate axis direction on the second strain resistance detecting elements 6 and 6 ′ can be detected.

As described above, the force applied to the operation unit 2 is:
It is separated into two coordinate axis directions, and the direction and size can be detected.

(Embodiment 2) FIG. 2 shows a pointing device using a load sensor according to Embodiment 2 of the present invention. The same components as those in Embodiment 1 are denoted by the same reference numerals and description thereof is omitted. The difference from the first embodiment is that the first strain resistance detecting elements 5 and 5 forming a pair
′ And the second strain resistance detecting elements 6, 6 ′ are arranged on the front and back of the elastic plate 1. In the second embodiment, the first and second strain resistance detecting elements 5, 5 ′, 6, 6 ′ forming a pair undergo compression / extension deformation due to the strain of the elastic plate 1.
This improves the detection accuracy.

Third Embodiment FIG. 3 shows a pointing device using a load sensor according to a third embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Example 3
This is a modification of the shape of the elastic plate 1 of the first embodiment, in which the elastic plate 7 is formed in a cross shape centering on the operation unit 2, and four end portions are fixed to the mounting table 3 by fixing portions 4. In the third embodiment, since the amount of deformation of the elastic plate 7 with respect to the applied force is larger than that of the first and second embodiments, a high sensitivity of the signal change with respect to the force is obtained, and the distortion is evenly generated. Therefore, high accuracy is not required for the positional accuracy of the first and second strain resistance detecting elements 5, 5 ', 6, 6'.
Increases productivity.

(Embodiment 4) FIGS. 4 and 5 show Embodiment 4 of the present invention.
Denotes an L-shaped elastic plate provided with a glass enamel coating layer on the surface, 2 denotes an operation unit, and 9 denotes a mounting base. Reference numeral 13 denotes a pivot supporting portion including a projection provided on the mounting table 9. The center of the elastic plate 8 is connected to the operation unit 2, and two surrounding portions are mounted on the mounting table 9.
At the fixing portion 10. The center of the elastic plate 8 is supported by a pivot supporting portion 13 provided on the mounting base 9. Further, the first and second strain resistance detecting elements 11 and 12 are formed by directly printing and coating a metal glaze resistor on the glass enamel coating layer provided on the surface of the elastic plate 8.

The operation of the fourth embodiment of the present invention will be described below. Move the operation unit 2 in the direction of “U” in FIG.
When a force is applied (parallel to), the portion of the elastic plate 8 at the second strain resistance detecting element 12 is deformed into a concave surface. On the other hand, the portion of the first strain resistance detecting element 11 undergoes torsional deformation by pivot support. In this case, although the resistance value of the strain resistance detecting element changes due to the deformation of the portion of the second strain resistance detecting element 12, the resistance value of the first strain resistance detecting element 11 does not change because only the torsional stress is applied. Next, when a force is applied to the operation unit 2 in the direction of “D” in FIG. 4 (parallel to the elastic plate 8), the portion of the first distortion resistance detecting element 11 in the elastic plate 8 is deformed into a concave surface, and A torsional stress is applied to the second strain resistance detecting element 12. In this way, the force applied to the operation unit 2 is separated in the direction of the two coordinate axes, and the direction and the magnitude can be detected.

In the fourth embodiment, the pivot support 13
Since a vertical load is received by the support, the horizontal load alone can be accurately detected, and as a result, a pointing device using a load sensor having excellent operability can be provided.

(Embodiment 5) FIG. 6 shows another arrangement example of the strain resistance detecting element. First and second paired with the first and second strain resistance detecting elements 11 and 12
The distortion resistance detecting elements 11 ′ and 12 ′ are arranged outside the fixed part 10 where the elastic plate 14 is extended. The first and second strain resistance detecting elements 11 'and 12' at this position are not affected even if the elastic plate 14 is distorted. In the fifth embodiment, a difference in resistance change between the first strain resistance detecting elements 11 and 11 'and the second strain resistance detecting elements 12 and 12', which form a pair, is calculated. By doing so, it is possible to cancel the temperature change of the strain resistance detecting element.

Embodiment 6 FIGS. 7A and 7B show a sixth embodiment of the present invention, and show a cross section. 15 is an elastic plate, 16
Denotes a support base, 17 denotes a mounting base, and 18 denotes an operation unit. The operating portion 18 and the elastic plate 15 are integrated, and a conical concave portion 19 is provided at the lower center of the operating portion 18. The support base 16 is provided with a pivot support section 20 composed of a conical projection, and the operation section 1
8 is in contact with the concave portion 19. With this support, the operation unit 18 can freely rotate around the tip of the pivot support unit 20 of the support base 16.
The operating portion 18 is supported by the pivot support portion 20 of the support base 16 even when the support 8 is pressed in the direction of the support base 16.

Reference numeral 21 denotes a support provided on the mounting table 17. The support 21 sandwiches the elastic plate 15 with the support 16, but has an appropriate clearance with respect to the thickness of the elastic plate 15. is there. Further, as shown in FIG. 7 (b), the relationship between the elastic plate 15 and the support portion 21 of the mounting base 17 is as follows. The columnar projection is to enter. With such a structure, the elastic plate 15 can freely slide only on a line connecting the center of the operation unit 18 and the support unit 21.

The elastic plate 15 is provided with the elastic plate 1 of the fifth embodiment.
4, a strain resistance detecting element is provided, but is omitted here.

Also in the sixth embodiment, the elastic plate 15 is deformed by the force applied to the tip of the operation unit 18, similarly to the other embodiments, and has a function as a load sensor. In the sixth embodiment, since the fixing portion in the direction parallel to the surface of the elastic plate 15 is only the concave portion 19 of the operation portion 18, the structure is not affected by expansion and contraction due to the temperature of the support base 16 and the mounting base 17. Has become.

(Embodiment 7) FIG. 8 shows the elastic plate of FIG. 6 shown in Embodiment 5 as a T-shaped elastic plate 22 and the strain resistance detecting elements 11 ', 12 'Is arranged. As in the fourth embodiment, the strain resistance detecting elements 11 'and 12' do not receive stress. In the seventh embodiment, since it is not necessary to pass the wiring pattern 22 near the fixing portion 10, the arm portion can be made thinner, and the size can be further reduced.

FIG. 9 shows an application example in which the load sensor of the present invention shown in FIGS. 4 and 5 is used as a pointing device of a full keyboard.
W element 25 is the load sensor of the fourth and fifth embodiments. SW elements 24 are arranged below each key top 23 as shown by broken lines, and a load sensor 25 shown by hatching is arranged between these SW elements 24. As is clear from this, the L-shape has a characteristic that it can be arranged well between the keys even if the sensor becomes large. The same applies to the T-shape.
This contributes to further downsizing of a notebook computer with a built-in pointing device.

FIG. 10 is a diagram showing the relationship between the elastic plate, the shaft, and the strain resistance detecting element in Examples 4 to 6 of the pointing device using the load sensor according to the present invention. Here, the pointing device of the sixth embodiment will be described as an example. The diameter of the connecting portion of the elastic plate 22 connected to the operation unit 2 is D. The width of the arm portions 22a and 22b on which the strain resistance detecting elements 11 and 12 are
And Let H be the distance between the strain resistance detecting elements 11 and 12 and the center of the operation unit 2.

At this time, when a horizontal load is applied in the direction "O" of the operation unit 2, the arm 22a of the elastic plate 22 on which the strain resistance detecting element 12 is disposed receives bending stress. At this time, the operation unit 2 is a rigid body, and when a bending stress is applied to the elastic plate 22 connected to the operation unit 2 which is a rigid body, the boundary between the operation unit 2 and the elastic plate 22 receives the maximum stress. , Arm 2
The intersection A between the central axis of 2a and the outer periphery of the operation unit 2 receives the maximum stress. This intersection A is H = 0.5D.

On the other hand, at this time, since the arm portion 22b receives the torsional stress, the arm portion 22b has a tensile stress.
Is zero at the neutral point, and the tensile stress increases as the distance from the central axis increases. Therefore, by disposing on the central axis of the arm portion 22b,
Strain for torsional stress is minimal. From such a stress distribution, the strain resistance detecting elements 11 and 12 are
By arranging near H = 0.5D on the central axes of a and 22b, a signal that is maximum for bending stress and minimum for torsional stress is obtained.

That is, when a torsional stress is applied to the rectangular elastic plate, the neutral point becomes the central axis of the rectangular elastic plate. In the sixth embodiment, the arm portion 22 on one side of the T-shaped elastic plate 22 is used.
Since the torsional stress is applied to a, the center point does not become a neutral point under the influence of the bending stress of the other arm 22b. In order to set the neutral point on the central axis, the diameter of the operation unit 2 which is a rigid body is increased and the two arms 22
What is necessary is just to prevent distortion from being transmitted to a and 22b.
That is, the circumference of the connecting portion between the operation unit 2 and the elastic plate 22 is set to 2
The diameter is set to be equal to or greater than the intersection of the two arms 22a and 22b with the outer side (point B in FIG. 10). That is,

[0034]

[Outside 1]

By doing so, the influence of the torsional stress is reduced, and the difference signal is minimized.

By defining the position of the strain resistance detecting element, the diameter of the operation section 2 and the dimensions of the arms 22a and 22b in this manner, the horizontal load applied to the operation section 2 can be reduced to two axes by minimizing the error. Can be separated.

(Eighth Embodiment) FIGS. 11A and 11B show an eighth embodiment of a pointing device using a load sensor according to the present invention. FIG. 11A is a perspective view, and FIG. b) is a sectional view. In the eighth embodiment, reference numeral 26 denotes an elastic plate, 27 denotes an operation unit, 28 denotes a mount, and 29 denotes a fixed unit. The center of the elastic plate 26 is fixed by the fixing portion 29 of the mounting base 28, and the operating portion 27
Is connected to the periphery of the elastic plate 26. When a force such as a load “o” is applied to the tip of the operation unit 27, the elastic plate 26
Is deformed by applying a stress to the center in the direction of the force. The eighth embodiment has a structure opposite to that of the embodiment shown in FIGS. 1 to 3, in which the center of the elastic plate 26 is fixed, and a load from the operation unit 27 is applied to the periphery.

In the eighth embodiment, the position (L in FIG. 11B) at which the operating section 27 applies a stress to the elastic plate 26 is determined according to the fourth to sixth embodiments.
It can be longer. A resin molded product is used at the tip of the operation section 27 in order to make the tip shape easy to operate at the portion where the fingertip is applied. In the eighth embodiment, L
Since the dimensions are long, the stress at the portion connected to the elastic plate 26 is small, and the deformation point of the resin is small, so that the point of action for deforming the elastic plate 26 is stabilized, whereby the deformation of the elastic plate 26 due to temperature is reduced. Fluctuations in volume are to be reduced.

Further, by using an enameled metal plate or a glass-coated metal plate as the elastic plate, it is tough against external stress and impact, and an assembling method such as caulking can be used to facilitate the assembly. In addition, since high-temperature processing is possible, a highly reliable metal glaze resistor can be used as the resistor.

[0040]

Load sensor of the present invention as described above, according to the present invention is, L
Glass hollow on a T-shaped or T-shaped elastic plate
-Since the two strain-sensitive resistors are formed directly on the coating layer by thick-film printing , there is no misalignment due to adhesion as in the prior art, and collectively and accurately. A strain sensitive resistor can be arranged, thereby obtaining a resistor having a high relative accuracy of the resistance value, and at the same time, the trimming is easy and the resistance value can be made more accurate. Also by providing the glass enamel coating layer on the elastic board, the strain sensitive resistor, which can be used a highly reliable metal glaze resistor can be a high temperature treatment
It is. Also, fix the two places around the elastic plate with fixed parts.
Turn the center of the elastic plate with the pivot support
Rollable and movement of the elastic plate in the direction perpendicular to the plane is restricted.
So that only horizontal loads can be accurately detected.
As a result, the load sensor has excellent operability.
It has excellent effects such as the ability to obtain
You.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a load sensor according to the present invention.

FIG. 2 is a perspective view of another embodiment.

FIG. 3 is a perspective view of another embodiment.

FIG. 4 is a perspective view of another embodiment.

FIG. 5 is a side view of the same.

FIG. 6 is a perspective view of another embodiment.

7A is a side sectional view of another embodiment of the present invention, and FIG.

FIG. 8 is a perspective view of another embodiment.

FIG. 9 is a top view illustrating a keyboard using the load sensor of the present invention.

FIG. 10 is a plan view of the main part.

FIG. 11 (a) is a perspective view of another embodiment of the present invention, and (b) is a side view and a sectional view of the same.

FIG. 12 is a perspective view of a conventional load sensor.

[Explanation of symbols]

 1,15 Elastic plate 2,18,27 Operating part 3,9,17,28 Mounting base 4,10,29 Fixed part 5,5 'First strain resistance detecting element 6,6' Second strain resistance detecting element 7, 26 Cross-shaped elastic plate 8, 14 L-shaped elastic plate 11, 11 'First strain resistance detecting element 12, 12' Second strain resistance detecting element 13, 20 Pivot support 21 Slide support 22 T-shaped elastic plate 23 Key top 24 Keyboard SW element 31 Shaft with square cross section 32,32 'A pair of strain gauges 33,33' Another pair of strain gauges

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-223836 (JP, A) JP-A-4-169827 (JP, A) JP-A-2-159530 (JP, A) JP-A 64-64 13414 (JP, A) Japanese Utility Model Showa 62-15358 (JP, U) Special Table Sho 62-500682 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01L 1/22 G01L 5 / 16 G06F 3/033

Claims (3)

(57) [Claims] 1. An L-shaped or T-shaped elastic plate and an elastic plate
A glass enamel coating layer provided on a conductive plate,
An operation unit connected to the center of the plate, and a central portion of the elastic plate
It is rotatable and the movement of the elastic plate in the direction perpendicular to the plane is restricted
Supported by the pivot support portion so that
A mounting base with two fixed parts around the elastic plate
Directly formed by thick film printing on the glass enamel coating layer
And a load sensor including the two strain-sensitive resistors . 2. The two other strain-sensitive resistors paired with two strain-sensitive resistors.
Two strain-sensitive resistors, two places around the elastic plate
Located on the elastic plate outside the fixing part to be fixed to
The load sensor according to claim 1 . 3. The diameter of an operating portion connected to the center of the elastic plate.
2. The load sensor according to claim 1, wherein the width of the elastic plate is larger than the width of the elastic plate .