JP2005249799A - Stress sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a variation in each resistor 2 in a stress sensor in which a post 6 is stuck or unified on the surface of an insulation substrate 3; and the direction and the magnitude of the stress can be obtained from a resistance value change of a resistance element 8, due to a stimulation to a plurality of the resistance elements 8 resulting from the stress applied to the post 6. <P>SOLUTION: The resistance element 8 consists of the resistor 2 formed by a screen printing between electrodes for the resistance elements used as a counterpart arranged on the surface of the insulation substrate 3. The electrode for the resistance element is connected by a conductor 9 into a substrate terminal 5 allotted to the end of the insulation substrate 3. The electrode for the resistance element, the conductor 9 and a printing accuracy adjusting material 7 have a predetermined height from the surface of the insulation substrate 3. For all of the plurality of resistance elements 8, the conductor, the printing accuracy adjusting material 7 and the electrode for the resistance element are arranged around over three directions of the single resistor 2, and the resister 2 is a resistor made of a carbon resin system. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resistance element, and as an application field thereof, for example, relates to a stress sensor that can be used for a pointing device for a personal computer, a multifunctional / multidirectional switch for various electronic devices, and the like.

  A stress sensor in which a post is fixed to or integrated with an insulating substrate surface, and the direction and magnitude of the stress can be grasped from a change in resistance value of the resistance element due to stimulation of a plurality of resistance elements caused by applying stress to the post Is disclosed in Japanese Patent Application Laid-Open No. 2000-267803. The formation of the resistance element which is the strain gauge disclosed here is by screen printing all the components of the resistance element on the ceramic substrate surface.

  As shown in FIG. 15, the resistance element 22 is arranged on four orthogonal straight lines along the surface of the insulating substrate 20 with the center of the surface of the insulating substrate 20 as an intersection, and at a substantially equidistant position from the intersection. And the center of the insulating substrate 20 surface and the center of the bottom surface of the post 30 having a square bottom surface substantially coincide with each other, and each side of the contour of the bottom surface of the post 30 faces each resistance element 22. It is fixed. Further, the substrate terminal portions 24 are arranged at the end portions at substantially constant intervals over the entire circumference of the insulating substrate 20. Further, since the conductor (electrode) connected to the resistance element 22 and the substrate terminal portion 24 are formed on the surface of the insulating substrate 20 by screen printing, they have a certain (predetermined) height from the surface of the insulating substrate 20. ing.

In recent years, in addition to the stress sensor in the form obtained by screen printing on the ceramic substrate surface, all the components of the resistance element have a conductor obtained by removing a part of the conductor layer on the surface and obtaining the remainder. Development of stress sensors using an insulating substrate is underway. This is because the conductor in such an insulating substrate has an advantage that it is easy to make a fine pattern as compared with a thick film technique such as a screen printing technique and has a low manufacturing cost.
JP 2000-267803 A

  However, the insulating substrate for the stress sensor is an insulating substrate having a conductor obtained by removing a part of the conductor layer on the surface, and the stress sensor uses a part of the conductor 9 as an electrode, and the insulating substrate. When a resistance element made of a resistor film formed between a pair of electrodes on a surface is used as a strain gauge, there is a problem that is not found in the above-described conventional technique.

  The problem is that the electrodes (conductors) that make up the resistance element were conventionally formed by screen printing technology, whereas the conductors were formed by removing a portion of the surface conductor layer and forming the remainder. Caused by

  An overview of the differences is shown in FIG. FIG. 7A is a schematic cross-sectional view of the resistance element 8 using a conductor (circuit pattern electrode 1) obtained by removing a part of the conductor layer on the surface of the insulating insulating substrate 3 as an electrode. FIG. 7B is a schematic cross-sectional view of the resistance element 8 using a conductor (resistance element electrode (hereinafter referred to as a thick film electrode)) obtained by screen printing, which is a thick film technique.

  The conductor height in FIG. 7A substantially depends on the thickness of the conductor layer made of copper or the like initially disposed on the surface of the insulating substrate 3. Usually, this thickness is about 18 to 36 μm. Furthermore, the insulating substrate 3 forms a conductive material in the through hole by plating, and the conductors 9 on both sides of the insulating substrate 3 are electrically connected to each other. In some cases, the height is further increased to about 40 to 70 μm. On the other hand, the thickness of the thick film electrode 13 in FIG. 7B can be arbitrarily set to some extent, and is usually set to about 10 μm.

  The difference in cross-sectional shape between the circuit pattern electrode 1 and the thick film electrode 13 will be described. The circuit pattern electrode 1 has a cross-sectional shape that approximates a rectangle, and it can be understood that the circuit pattern electrode 1 has a surface that is substantially perpendicular to the surface of the insulating substrate 3 (FIG. 7A). On the other hand, the cross-sectional shape of the thick film electrode 13 is composed of a curve mainly composed of an oblique component with respect to the surface of the insulating substrate 3, and it can be understood that the thick film electrode 13 is mainly composed of a gentle surface with respect to the surface of the insulating substrate 3 (FIG. 7 (b)).

  Due to the difference between the circuit pattern electrode 1 and the thick film electrode 13, the resistance element 8 (FIG. 7A) using the circuit pattern electrode 1 as an electrode is the resistance element 8 using the thick film electrode 13 (FIG. 7 (FIG. 7A)). As compared with b)), the resistance value variation becomes larger. This is because it is difficult for the former to make the shape of the resistor 2 uniform. A resistance element 8 that is forced to form an excessively long trimming groove in a so-called trimming process that adjusts to a desired resistance value when the resistance value variation is large, and a resistance element that hardly requires the trimming groove to be formed 8 will be mixed. Even if the resistance values are the same, if the trimming groove lengths are extremely different in this way, it is impossible to obtain resistance value stability due to the ambient environment, particularly the ambient temperature. That is, even if the nominal resistance value is the same, the resistance element 8 having a large variation in characteristics other than the resistance value is manufactured. In the stress sensor using the resistance element 8 having a trimming groove as a strain gauge, fine cracks around the trimming groove may spread due to long-term use, and the initial resistance value may not be maintained.

  Thus, when the circuit pattern electrode 1 is used, the shape of the resistor 2 formed with a thick film by a thick film technique such as a screen printing technique is more stable between the electrodes than when the thick film electrode 13 is used. There are two possible reasons for this difficulty.

  The first reason is that the height of the circuit pattern electrode 1 is high as described above. Taking the case where the resistor 2 film is formed by screen printing as an example, a substantially constant amount of paste-like resistor is disposed between the pair of circuit pattern electrodes 1 through a mask (screen). Then, the shape of the fixed resistor 2 varies depending on factors such as the ambient temperature, paste temperature, and the standing time until the shape of the resistor 2 is fixed by baking or curing it after screen printing. For example, when the paste viscosity is low due to a high ambient temperature, the upper surface of the resistor 2 between the pair of circuit pattern electrodes 1 becomes substantially flat and has a relatively stable shape. On the other hand, when the paste is disposed between the pair of circuit pattern electrodes 1 in a high-viscosity state, the paste is solidified by firing and curing while maintaining the initial shape of the disposed portion to some extent. This tendency is considered to be remarkable when the resistor paste contains a thermosetting resin. This is because it is considered that the paste viscosity is hardly lowered even by heating. Here, if the height of the circuit pattern electrode 1 is high, the periphery of the circuit pattern 1 becomes a free-flowing region of the paste when the resistance paste viscosity is high. This is because the paste near the top surface of the circuit pattern electrode 1 moves from a high place to a low place by its own weight.

  Further, when forming the resistor 2 film by the screen printing method, if the height of the circuit pattern electrode 1 is excessively high, the squeegee easily collides with the circuit pattern electrode 1 when the pasty resistor is passed through the mask by the squeegee. Become. Then, the squeegee causes the paste-like resistor to pass through the mask with a non-smooth movement, causing the amount of paste-like resistor passing through the mask to vary, and further causing a shift in the position where the paste-like resistor is disposed, resulting in a circuit pattern. The phenomenon that the shape of the resistor 2 formed between the electrodes 1 becomes difficult to stabilize is spurred.

  The second reason is that the circuit pattern electrode 1 has a surface substantially perpendicular to the surface of the insulating substrate 3. It is extremely difficult to control the film thickness of the resistor 2 existing on the substantially vertical surface to a constant value. This is because, as described above, when the paste near the top surface of the circuit pattern electrode 1 moves from a high place to a low place by its own weight, it is difficult to predict how the paste is moved along the substantially vertical plane. is there. The second reason is not only having the substantially vertical surface, but also accompanying the first reason, the shape of the resistor 2 becomes difficult to stabilize. That is, when the height of the circuit pattern electrode 1 is low, the paste near the top surface of the circuit pattern electrode 1 has a short distance to move from a high place to a low place by its own weight, and the resistance in the vertical direction from the substantially vertical face is short. This is because the variation in resistance value of the resistance element due to the difference in the thickness of the body 2 is almost negligible.

  This second reason is not limited to the formation of the resistor 2 film by the thick film technique such as screen printing, but also applies to the resistance element 8 by the resistor 2 film formation by the thin film technique such as sputtering. For example, if the sputtering operation is performed in a state where the circuit pattern electrode 1 is high and has a substantially vertical surface, it is difficult to control the thickness of the resistor 2 film attached to the substantially vertical surface to a constant value. It is. That is, it is difficult to make the shape of the resistor 2 constant in the formation of the resistor 2 film by the thin film technology, and the resistance value is likely to vary.

  For this reason, the problem to be solved by the present invention is that a part of the conductor layer on the surface of the insulating substrate is removed, and a part of the conductor obtained as the remainder is used as an electrode, on the surface of the insulating substrate 3. In a resistance element having a resistor formed in a film between a pair of electrodes, variation in resistance value is reduced, and a stress sensor using the resistance element is provided.

In order to solve the above-described problem, the stress sensor of the present invention has a post 6 fixed or integrated on the surface of the insulating substrate 3, and the resistance element due to stimulation of the plurality of resistance elements 8 due to the application of stress to the post 6. In the stress sensor capable of grasping the direction and magnitude of the stress from the resistance value change of 8, the resistance element 8 is formed between the pair of resistance element electrodes arranged on the surface of the insulating substrate 3 by a screen printing method. The resistor element electrode is connected to a substrate terminal portion 5 disposed at one end of the insulating substrate 3 by a conductor 9, and the resistor element electrode, the conductor 9, and the printing accuracy adjustment The member 7 has a predetermined height from the surface of the insulating substrate 3, and the conductor, the printing accuracy adjusting member 7, and the resistor element electrode are arranged in a single resistance for all the resistor elements 8. Take more than three sides of body 2 See, characterized in that the resistor 2 is the resistor of the carbon resin system.
Here, the insulating substrate 3 can be mainly composed of glass fiber mixed epoxy resin.
With reference mainly to FIG. 1, the stress sensors having the configurations 1a to 1d of the present invention will be described below. In order to solve the above-described problem, the stress sensor having the configuration 1a according to the present invention has the post 6 fixed or integrated on the surface of the insulating substrate 3, and applies the stress to the post 6 to the plurality of resistance elements 8. It is a stress sensor that can grasp the direction and magnitude of the stress from the change in resistance value of the resistance element 8 due to stimulation, and the resistance element 8 is a pair of resistance element electrodes (on the insulating substrate 3 surface). It is composed of a resistor 2 formed by a screen printing method between circuit pattern electrodes 1), and the resistor element electrode is connected to a substrate terminal portion 5 disposed at one end of an insulating substrate 3 by a conductor 9, The resistance element electrode and the conductor 9 have a predetermined height from the surface of the insulating substrate 3, and the arrangement of the conductor 9 and the resistance element electrode in the vicinity of the plurality of resistance elements 8 is the same or similar. It is characterized by being.

  In order to solve the above-mentioned problem, the configuration of the stress sensor 1b of the present invention is that the post 6 is fixed or integrated on the surface of the insulating substrate 3, and the plurality of resistance elements 8 due to the stress applied to the post 6 is obtained. A stress sensor capable of grasping the direction and magnitude of the stress from the change in resistance value of the resistance element 8 due to the stimulation of the resistance element 8, wherein the resistance element 8 is a pair of resistance element electrodes ( It is composed of a resistor 2 formed by a screen printing method between circuit pattern electrodes 1), and the resistor element electrode is connected to a substrate terminal portion 5 disposed at one end of an insulating substrate 3 by a conductor 9, The resistance element electrode and conductor 9 or the printing accuracy adjusting member 7 has a predetermined height from the surface of the insulating substrate 3, and the conductor 9 and the resistance element electrode or printing in the vicinity of all of the plurality of resistance elements. Accuracy adjustment unit Arrangement 7, characterized in that the same or similar.

  By providing the above-described configurations 1a and 1b of the present invention, that is, the arrangement of the conductor 9 and the resistor element electrode (circuit pattern electrode 1) or the printing accuracy adjusting member 7 is the same for all of the plurality of resistor elements. Alternatively, by being similar, the conductor 9 and the resistor element electrode or the printing accuracy adjusting member 7 of the entire insulating substrate 3 constituting one stress sensor are arranged with good balance. Therefore, the squeegee operation when the resistor 2 is screen-printed and the squeegee shape when the resistor paste is discharged between the pair of circuit pattern electrodes 1 on the surface of the insulating substrate 3 are made uniform for each resistor 2. Can do. Therefore, variation in the shape of each resistor 2 within one stress sensor can be suppressed, and the problem of the present invention can be solved. Incidentally, the material of a normal squeegee is made of a rubber material, and its shape is easily and elastically changed. Therefore, the paste can be passed through the screen opening.

  FIG. 2A shows a state of the screen printing process as a side view observed from the side surface direction orthogonal to the moving direction of the squeegee. FIG. 2B shows the same period as FIG. 2A observed through the gap between the screen and the insulating substrate 3 and the observation angle rotated by 90 ° along the surface of the insulating substrate 3. In FIG. 2B, when the circuit pattern electrode 1 that is the pair of electrodes for the right side resistor and the pair of circuit pattern electrodes 1 on the left side are compared, the conductor 9 and the printing accuracy adjusting member 7 are present around the former. In contrast, they exist around the latter. Accordingly, the squeegee operation when the resistor 2 is screen-printed between the former circuit pattern electrodes 1 and the latter circuit pattern electrode 1 and the squeegee shape when the resistor paste is discharged onto the surface of the insulating substrate 3 are different. It is natural to come. Therefore, by adopting the above-described configurations 1a and 1b of the present invention, the arrangement conditions of the conductor 9 around the circuit pattern electrode 1 and the printing accuracy adjusting member 7 can be made uniform, and when the resistor 2 described above is formed by screen printing. The squeegee operation and the squeegee shape when the resistor paste is discharged onto the surface of the insulating substrate 3 can be made uniform.

  The above stimulation refers to the expansion and contraction of the resistance element 8 disposed on the insulating substrate 3 due to the bending of the insulating substrate 3, the pressing of the resistance element 8 so that the bottom surface of the post 6 does not go through the insulating substrate 3, the pressing Release.

  Generally, a stress sensor functions as a stress sensor only when a control unit that detects and calculates electrical characteristics such as the resistance value is provided. However, in this specification, for the sake of convenience, the portion excluding the control unit is expressed as “stress sensor”.

  Further, “the post 6 is fixed to the surface of the insulating substrate 3” means a state in which the post 6 and the insulating substrate 3 are separate members and are fixed with an adhesive or the like. Further, “the post 6 is integrated with the surface of the insulating substrate 3” means that the post 6 and the insulating substrate 3 are formed by integral molding or the like. In the latter case, in the present specification, when there is a place expressed as “the contour of the bottom surface of the post 6”, it indicates a portion corresponding to the “contour of the bottom surface of the post 6” in the former case.

  The electrode for a resistance element is a substance having electron conductivity that comes into contact with the resistor 2, and is often a part of the conductor 9. For example, it refers to the circuit pattern electrode 1.

  The predetermined height is several μm to several tens of μm when the conductor 9 is formed thick by screen printing or the like. Further, when the conductor 9 is formed into a thin film by sputtering or the like, the thickness is about several tens of nm. Further, when a technique for forming the conductor 9 on a normal printed circuit board such as a so-called subtract method or additive method is employed, the thickness is several μm to several tens of μm. Moreover, since it is “predetermined”, a form embedded in the surface of the insulating substrate 3 is excluded. Here, this “predetermined” height is usually a “constant” height. That is, it means that there is no great variation in the height of the conductor or the like in one stress sensor.

  Here, “constant” means substantially constant, not strictly constant. For example, variations in the amount of adhesion due to plating are ignored. The advantage of “constant” is that the squeegee operation during screen printing becomes smoother.

  In addition, the term “one end” is narrowly defined based on the expression, and one end of the insulating substrate 3 is shown in FIGS. 6A to 6G so as not to be interpreted as only one side constituting the insulating substrate 3. The main part of the structure by which the board | substrate terminal part 5 was distribute | arranged to is illustrated. That is, “one end” refers to a relatively narrow region of the entire periphery of the insulating substrate 3.

  Further, “the vicinity of all of the resistance elements 8” is described above, but the vicinity thereof is a region that greatly affects the shape of the resistor 2 obtained by forming the resistor 2 by the screen printing method. When the resistor 2 is formed by screen printing, a region that causes a slight variation in the shape of the resistor 2 such that the influence on the stress sensor characteristics can be ignored is not included here.

  The “similarity” is judged based on the degree to which the influence on the stress sensor characteristics can be ignored in principle. However, it is a condition that the shapes to be reasonably compared are approximated. For example, the arrangement of the circuit pattern electrode 1 near the four resistance elements 8 shown in FIG. 1 or the printing system adjusting member 7 and the resistor 2 is similar in appearance as a whole.

  The printing accuracy adjusting member 7 is a member other than the conductor 9 and the resistor element electrode (circuit pattern electrode 1), and is added to the conductor 9 and the resistor element electrode as necessary, and the resistor 2 is attached. This is a member provided on the surface of the insulating substrate 3 in order to make the squeegee operation for screen printing and the squeegee shape for discharging the resistor paste onto the surface of the insulating substrate 3 uniform for each resistor 2. The material may be a conductor or an insulator.

  The printing accuracy adjusting member 7 is preferably formed at the same time as the conductor 9 and the resistor element electrode (circuit pattern electrode 1) from the viewpoint of making their heights substantially constant and facilitating manufacture. For example, when these three are formed by screen printing, these three are patterned (opening formation) in one plate making. Further, when these three are patterned by the so-called substruct method, they are similarly obtained by one etching operation.

  Further, in order to solve the above-described problem, the first sensor configuration of the stress sensor according to the present invention is such that the post 6 is fixed or integrated on the surface of the insulating substrate 3, and a plurality of resistance elements due to the application of stress to the post 6 are applied. A stress sensor capable of grasping the direction and magnitude of the stress from a change in resistance value of the resistance element due to stimulation, wherein the resistance element is a pair of resistance element electrodes (circuit pattern electrodes) disposed on the surface of the insulating substrate 3 1) It is comprised by the resistor 2 formed by the screen printing method between, and the said electrode for resistive elements is connected to the board | substrate terminal part 5 distribute | arranged to one end of the insulated substrate 3 by the conductor 9, and the said resistive element The electrode and conductor 9 or the printing accuracy adjusting member 7 has a predetermined height from the surface of the insulating substrate 3, and the conductor 9 and the resistor element electrode (circuit pattern electrode 1) in the vicinity of all of the plurality of resistor elements. Young Arrangement of printing precision adjustment member 7, characterized in the the thing as to surround the above three sides of the resistor 2 periphery.

  The feature of the 1c configuration of the present invention compared with the configurations of the first 1a and 1b of the present invention is that the latter is a conductor 9 and a resistor element electrode (circuit pattern) in the vicinity of all the resistor elements. The arrangement of the electrode 1) or the printing accuracy adjusting member 7 is the same or similar, whereas the former is a conductor 9 in the vicinity of all of the plurality of resistance elements 8 and the resistance element electrodes (circuit pattern electrode 1) or The arrangement of the printing accuracy adjusting member 7 is such that it surrounds at least three sides of the periphery of the resistor 2. The meaning of terms in other points and the effects brought about by each component are common. Needless to say, this does not deny the sharing of the configurations of 1a and 1b with the configuration of 1c. For example, the four resistance elements 8 shown in FIG. 1 have both the 1a configuration, the 1b configuration, and the 1c configuration.

  The “periphery of the resistor 2” is a region near the end of the resistor that greatly affects the shape of the resistor 2 obtained by forming the resistor 2 by the screen printing method, and an area outside it. This is approximately the resistor element electrode (circuit pattern electrode 1) in contact with the resistor 2 shown in FIG. 1 or the outside thereof, the periphery of the conductor 9 or the portion close to the resistor 2 in the printing accuracy adjusting member 7, and the like. . When the resistor 2 is formed by screen printing, a region that causes a slight variation in the shape of the resistor 2 such that the influence on the stress sensor characteristics can be ignored is not included here.

  The squeegee operation when the resistor 2 is screen-printed and the squeegee-shaped resistors 2 when the resistor paste is discharged onto the surface of the insulating substrate 3 can be made uniform by adopting the configuration 1c. is there. The reason is that at least three sides of the periphery of the resistor 2 are surrounded by the conductor 9 and the resistor element electrode (circuit pattern electrode 1) or the printing accuracy adjusting member 7, so that at least the vicinity of the resistor 2 is printed, the conductor 9 and In many cases, there are a large number of contact points through the screen between the resistance element electrode or the printing accuracy adjusting member 7 and the squeegee, and the contact points cause the squeegee operation or the resistor paste on the surface of the insulating substrate 3. This is to contribute to the uniformization of each resistor 2 having a squeegee shape when discharging.

  In order to solve the above-described problem, the first sensor configuration of the stress sensor according to the present invention is such that the post 6 is fixed or integrated on the surface of the insulating substrate 3, and the plurality of resistance elements 8 resulting from the application of stress to the post 6. A stress sensor capable of grasping the direction and magnitude of the stress from the change in resistance value of the resistance element due to the stimulation of the resistance element, wherein the resistance element 8 is a pair of resistance element electrodes (on the insulating substrate 3 surface) The circuit pattern electrode 1) is composed of a resistor 2 formed by a screen printing method, and the circuit pattern electrode 1 is connected to a substrate terminal portion 5 disposed at one end of the insulating substrate 3 by a conductor 9, The circuit pattern electrode 1 and the conductor 9 or the printing accuracy adjusting member 7 have a predetermined height from the surface of the insulating substrate 3, and the circuit pattern electrode 1 so as to surround all of the plurality of resistance elements intermittently or continuously. And guidance 9 or printing accuracy adjustment member 7, characterized in that the arranged.

  The 1d configuration of the present invention is characterized in contrast to the 1c configuration of the present invention in that the latter surrounds a plurality of resistance elements individually and a resistance element electrode (circuit pattern electrode 1) or printing. Whereas the accuracy adjusting member 7 is present, the former is that there are the conductor 9 and the resistor element electrode or the printing accuracy adjusting member 7 surrounding the plurality of resistance elements together. The meaning of terms in other points and the effects brought about by each component are common. Further, it goes without saying that the 1a configuration and / or the 1b configuration and / or the 1c configuration and the 1d configuration are not denied. Rather, the advantages of both are added, which is more preferable.

  In these configurations 1a to 1d, as a constituent member of the stress sensor, a metal foil is attached to the surface of the insulating substrate 3, and then an unnecessary portion of the metal foil is etched, and the resistance element electrode (circuit pattern electrode 1), What obtained the conductor 9 or the printing precision adjustment member 7 is preferably used. The component member is generally used for the resistive element as described above, compared to the case where the resistive element electrode, the conductor 9 or the printing accuracy adjusting member 7 is formed on the surface of the insulating substrate 3 by thick film / thin film technology such as screen printing or sputtering. The height of the electrode, the conductor 9 or the printing accuracy adjusting member 7 from the surface of the insulating substrate 3 is high. This is because it depends on the thickness of the metal foil or the conductive substance is deposited on the metal foil by an electroless plating process for forming a conductive substance on the inner wall of the through hole. The thickness of the metal foil is currently about 9 to 36 μm, and usually about 18 μm. When the electroless plating process is added to this, the height of the circuit pattern electrode 1, the conductor 9, or the printing accuracy adjusting member 7 is usually 30 to 50 μm. As described above, with respect to the resistor element electrode, the conductor 9 or the printing accuracy adjusting member 7 having a high height from the surface of the insulating substrate 3, the squeegee operation when the resistor 2 is screen-printed or the resistor paste is insulated. It is particularly difficult to equalize each squeegee-shaped resistor 2 when discharging onto the surface of the substrate 3, and the application of the present invention greatly contributes to the improvement of the stress sensor characteristics.

  This large contribution is obtained when the resistance element electrode (circuit pattern electrode 1), the conductor 9 or the printing accuracy adjusting member 7 has a height from the surface of the insulating substrate 3 of 10 μm or more, and when it is 20 μm or more. A larger contribution can be obtained, and a larger contribution can be obtained when the thickness is 30 μm or more.

  In order to solve the above-described problem, the stress sensor manufacturing method according to the present invention includes a post 6 fixed or integrated on the surface of the insulating substrate 3 and stimulating the plurality of resistance elements 8 due to the application of stress to the post 6. A stress sensor manufacturing method capable of grasping the direction and magnitude of the stress from the change in resistance value of the resistance element 8 due to the resistance element 8, wherein the resistance element electrode (circuit pattern electrode 1) is one end of the insulating substrate 3. 1st process which forms the circuit pattern electrode 1, the board | substrate terminal part 5, and the conductor 9 so that it may connect with the board | substrate terminal part 5 distribute | arranged to the board | substrate terminal part 5, and insulation so that it may not cover the said circuit pattern electrode 1 at least A second step of disposing the film on the surface of the insulating substrate 3, and a third step of forming the resistor 2 by screen printing between the pair of circuit pattern electrodes 1 disposed on the surface of the insulating substrate 3, The first step, the second work And a third step which comprises carrying out in this order.

  In the first step, a conductor paste is screen-printed on the surface of an insulating substrate 3 such as alumina, or a copper foil is attached to the surface of a glass-molded epoxy resin plate-like molded body, and the portions other than the portion to be left as the conductor 9 are etched. It is realized by a method of depositing and forming the conductor 9 on a necessary portion by a so-called substruct method or a so-called additive method or a plating method, which is removed by processing.

  In the second step, the squeegee operation at the time of forming the resistor 2 by the screen printing method in the subsequent third step and the squeegee shape at the time of discharging the resistor paste onto the surface of the insulating substrate 3 are set for each resistor 2. This is a step of adjusting the heights of the resistance element electrode, the substrate terminal portion 5 and the conductor 9 from the surface of the insulating substrate 3 in order to make them uniform. That is, as described above, the higher the height of the electrode for the resistance element, the conductor 9, or the printing accuracy adjusting member 7 from the surface of the insulating substrate 3, in other words, the unevenness of the surface of the substrate to be contacted by the screen printing squeegee through the screen. The larger the difference, the more difficult it is to equalize the squeegee operation described above. Therefore, in order to reduce or eliminate the unevenness difference, the surface of the insulating substrate 3 is raised and brought close to the height of the resistance element electrode or the conductor 9, or the conductor 9 is covered with the insulating film beyond the height. It is.

  When the stress sensor bends the insulating substrate 3 due to the stress applied to the post 6 and the resistance element 8 bends accordingly, and the resistance value of the resistance element 8 is sensed at that time, the insulating film is It is preferable that the material is more flexible than the insulating substrate 3. This is because if the insulating film is made of a material having rigidity higher than that of the insulating substrate 3, there is a possibility that the bending of the insulating substrate 3 may be hindered. For example, when the insulating substrate 3 material is an epoxy resin molded body mixed with glass fiber, a cured silicone resin paste or the like can be suitably used. In this case, for example, the paste is disposed so as to cover the surface of the insulating substrate 3 and the conductor 9 disposed on the surface of the insulating substrate 3 by screen printing or the like. Then, the paste on the conductor 9 at a high location flows to the surface of the insulating substrate 3 at a low location, and then the paste is heated and cured to form an insulating film, and the unevenness difference can be reduced or eliminated. . At this time, attention should be paid so that the paste is not disposed on the surface of the resistance element electrode (circuit pattern electrode 1). The reason is to prevent the presence of a substance that hinders electrical connection with the resistor 2 formed in a later step. The resistance element electrode surface referred to here is the top surface and / or the side surface of the electrode. Therefore, it is needless to say that an insulating film may be disposed between the electrodes on which the resistor 2 is disposed if the top surface of the electrode is exposed.

  Here, the means for preventing the paste from being arranged on the surface of the circuit pattern electrode 1 is, for example, a masking process for preventing contact between the paste and the circuit pattern electrode 1, and mask removal after the paste is cured. In addition, after the paste is deposited and cured on the surface of the circuit pattern electrode 1, the surface of the circuit pattern electrode 1 is ground to remove the paste.

  The first configuration of the resistance element 8 of the present invention that solves the above-described problems is a conductor on the surface of the insulating substrate 3 obtained by removing a part of the conductor layer on the surface and obtaining the remaining part or by the additive method. 9 includes an electrode (circuit pattern electrode 1) and a resistor 2 that is formed between the pair of circuit pattern electrodes 1 on the surface of the insulating substrate 3, and includes a distance between the pair of electrodes (L ) And electrode height (h) ratio L / h is 30 or more.

  FIG. 9 shows the dimension measurement positions of the interelectrode distance (L) and the electrode height (h). As means for setting the ratio L / h to 30 or more, there are means for reducing the electrode height (h) and means for increasing the interelectrode distance (L). Needless to say, there is a means of using these means together.

  By means of lowering the electrode height (h), it is possible to reduce variations in resistance value of the resistance element 8 due to the first reason and the second reason described above. Further, by this means, by setting the ratio L / h to be 30 or more, a part of the conductor layer on the surface is removed, and a part of the conductor 9 obtained as the remaining part or obtained by the additive method is applied to the electrode ( Even if the resistance element 8 has the resistor 2 formed as a circuit pattern electrode 1) between the pair of electrodes on the surface of the insulating substrate 3, variation in the resistance value can be reduced.

  Here, when the electrode height (h) is lowered, the structure in which the surface of the insulating substrate 3 and the top surface of the circuit pattern electrode 1 are on the same plane, or the top surface of the circuit pattern electrode 1 at a position lower than the surface of the insulating substrate 3. In some configurations, the value of h is 0 or less, and the ratio L / h is not 30 or more. However, even in this case, the same effect as the first and second configurations can be obtained. Therefore, in the present invention, the case where the value of h is 0 or less is also included in the configuration of the present invention. .

  Further, by setting the ratio L / h to 30 or more by means of increasing the interelectrode distance (L), the shape of the resistor 2 in the vicinity of the circuit pattern electrode 1 due to the first reason and the second reason described above. Even when there is a variation in resistance, the variation in resistance value can be negligible. That is, in the resistor 2 between the pair of circuit pattern electrodes 1, the resistance value of the resistance element 8 is increased by increasing the ratio of the resistor 2 that is offshore from the surface of the circuit pattern electrode 1 and has a relatively reproducible shape. The variation is reduced. In other words, among the factors that determine the resistance value, the unstable factor (resistor 2 near the circuit pattern electrode 1) and the stable factor (offshore from the surface of the circuit pattern electrode 1, relatively reproducible in shape) By increasing the stable factor ratio with respect to a certain resistor 2), the resistance value variation of the resistance element 8 is suppressed.

  In the resistance element 8 having the first configuration of the present invention, the technical meaning of setting the ratio L / h to 30 or more depends on the experimental result. When the ratio L / h was about 24, the resistance value variation of the resistance element 8 was in the range of ± 17% (n = 30). Therefore, when the ratio L / h is about 30, the resistance value variation of the resistance element 8 is in a range of ± 9% (n = 30), and thereafter the ratio L / h is about 40, about 45, about 50, about Assuming 55 and about 60, the resistance value variation slightly decreased in order, but the difference did not increase significantly compared with the case where the ratio L / h was about 30. This is the process / reason for inducing the “ratio L / h of 30 or more”.

  In order to solve the above-described problems, the manufacturing method of the resistance element having the first configuration according to the present invention includes the fourth step of obtaining the conductor 9 on the surface of the insulating substrate 3 and the height of a part or all of the conductor 9. And a sixth step of forming a film of the resistor 2 between the pair of electrodes on the surface of the insulating substrate 3, using a part of the conductor 9 as an electrode. The fourth to sixth steps are performed in the order of the numbers, and in the fifth step, the ratio L / h between the pair of inter-electrode distances (L) and the conductor 9 height (h) is set to 30 or more, or The value of h is 0 or less.

  The fourth step is a step of removing the conductor 9 layer on the surface of the insulating substrate 3 as described above, or obtaining the conductor 9 layer on the surface of the insulating substrate 3 by an additive method.

  The fifth step is based on, for example, a pressing step on the surface of the insulating substrate 3. This is because the circuit pattern electrode 1 once formed is sunk into the insulating substrate 3, or the circuit pattern electrode 1 itself is deformed to adjust the electrode height (h) to be lower, and the ratio L / This is a step of setting h to 30 or more. The pressing step here includes a pressing step for the entire surface of the insulating substrate 3 by a roller press, a pressing by pressing using a flat plate without a depression as a die, or a pressing step only for a portion corresponding to the circuit pattern electrode 1. It is.

  Further, the fifth step may be, for example, a grinding or acid treatment step on the surface of the insulating substrate 3. In this process, mechanical grinding with sandpaper or the like, or the insulating substrate 3 is immersed in an acidic solution to dissolve the metal, and as a result, the circuit pattern electrode 1 height (h) is adjusted to be low, and the ratio L This is a step of setting / h to 30 or more. In this case, when using the insulating substrate 3 having a portion in which the conductor 9 pattern on both surfaces of the insulating substrate 3 is conducted through the conductive material in the through hole, the conductive material in the through hole is not excessively dissolved. It is preferable to mask the through-hole portion so as not to contact the acidic solution.

  In the first configuration of the resistance element 8 of the present invention, the circuit pattern on both surfaces of the insulating substrate 3 is electrically connected via the conductive material in the through hole, and a part of the conductor 9 on the surface of the insulating substrate 3 is formed as a circuit pattern. When the electrode 1 and the resistor 2 formed between the pair of electrodes on the surface of the insulating substrate 3 are provided, the electrode height (h) may be particularly high, and the application of the present invention is preferable. The reason why the electrode height (h) may be increased is that, in the so-called double-sided wiring board manufacturing process, an electroless plating is performed in order to form a conductive layer on the inner wall of the through hole of the insulating substrate 3 and to conduct the wiring on both sides. This is because an electroless plating layer is also formed on the portion that becomes the circuit pattern electrode 1 at that time.

  As described above, the fifth step in the case of including the plating step may be a plating treatment step into the through-hole of the insulating substrate 3 after covering the pair of electrodes on the surface of the insulating substrate 3. And it adjusts so that electrode height (h) may be kept low, and ratio L / h shall be 30 or more.

  In the present invention, it goes without saying that two or more of the exemplified fifth steps may be combined.

  Further, in the second configuration of the stress sensor of the present invention, the post 6 is fixed or integrated on either surface of the insulating substrate 3 constituting the resistance elements 8 of all the first configurations of the present invention described above. It is characterized in that the direction and magnitude of the stress is grasped by a change in resistance value of the resistance element 8 resulting from the application of stress to the post 6.

  For example, as shown in FIG. 1 and FIG. 8, the stress sensor is formed on two orthogonal straight lines along the surface of the insulating substrate 3 with the center of the sensor effective area of the surface of the insulating substrate 3 constituting the resistance element 8 as an intersection. In addition, the resistance element 8 is disposed at a substantially equidistant position from the intersection, and the post 6 is fixed or integrated with the surface of the insulating substrate 3 so that the center of the surface of the insulating substrate 3 and the center of the bottom surface of the post 6 substantially coincide. The direction and strength of the stress are grasped from the change in resistance value caused by the expansion, contraction, or compression of the resistance element 8 caused by the application of stress to the post 6.

  An example of the configuration of the stress sensor of the present invention will be further described with reference to FIG. The insulating substrate 3 is made of, for example, an epoxy resin plate mixed with glass fiber. Four pairs of circuit pattern electrodes 1 are provided on the lower surface of the insulating substrate 3, and a resistor 2 is disposed between each electrode, and a resistance element 8 is constituted by these. The resistance elements 8 are arranged on two perpendicular lines along the surface of the insulating substrate 3 with the center of the surface of the insulating substrate 3 as an intersection, and at substantially equidistant positions from the intersection. A post 6 having a substantially square bottom surface is fixed to the upper surface of the insulating substrate 3 with an adhesive or the like. At this time, the center of the bottom surface of the post 6 is made to substantially coincide with the center of the surface of the insulating substrate 3.

  Further, an L-shaped hole 10 is provided in the insulating substrate 3 such that the L-shaped corner is directed toward the center of the insulating substrate 3. The hole 10 has a role of easily bending the insulating substrate 3 due to a stress applied to the post 6 and a role of efficiently transmitting the stress to each resistance element 8. That is, if stress is applied to the post 6 in an arbitrary direction without the hole 10, the amount of bending of the insulating substrate 3 may not be sufficient, and the stress applied in the arbitrary direction is not related to the direction. It is preferable that the hole 10 is formed because there is a possibility of propagation up to 8.

  A trimmable chip resistor 11 connected in series with each resistance element 8 is disposed on the upper surface of the insulating substrate 3. The resistive element 8 on the lower surface of the insulating substrate 3 and the trimmable chip resistor 11 on the upper surface of the insulating substrate 3 are electrically connected through an insulating substrate 3 through hole (via hole) (not shown). When it is difficult to adjust the resistance value of each resistive element 8 within a certain range, the trimmable chip resistor 11 trims the trimmable chip resistor 11 with a laser trimmer or the like, and the resistive element 8 and the trimmable chip resistor This is required when the sum of the resistance values with the device 11 is adjusted within a certain range. The electrical connection state between the resistance element 8 and the trimmable chip resistor 11 at that time is as shown in FIG. 4, for example. An electrical signal from the stress sensor is output via the terminal 10.

  The support hole 12 is used for fixing the stress sensor when the stress sensor is fixed to a housing of an electronic device or the like. In the fixed state, the peripheral edge portion of the insulating substrate 3 outside the hole 10 becomes a non-deformed portion that hardly deforms even when stress is applied to the post 6, and the inside of the hole 10 is deformed when stress is applied to the post 6, and the resistance element It becomes a deformation part which expands and contracts 8. The trimmable chip resistor 11 is preferably arranged in the non-deformed portion so that the resistance value does not change under the influence of deformation of the insulating substrate 3.

  The meanings of the terms used in the stress sensor having the second configuration are the same as those of the stress sensors having the configurations 1a to 1d. Needless to say, the combination of the configurations of the first to first d and the second configuration is not denied. Rather, the advantages of these configurations are added, which is more preferable.

  In the configuration shown in FIG. 8, in particular, the hole 10, the support hole 12, and the trimmable chip resistor 11 are optional configuration requirements (not essential requirements) for the stress sensor of the second configuration. Even if these are included in the configuration requirements, the shape of the hole 10 is not limited to the L shape, and the arrangement of the support holes 12 is not limited to the four corners of the insulating substrate 3 having a rectangular outer shape. The shape of the hole 10 can be changed as appropriate according to restrictions on design of the stress sensor, required functions, applications, etc., for example, a circle, a rectangle, a rounded rectangle, and the like. Further, the support hole 12 can be arranged near the middle of each side of the end portion of the rectangular insulating substrate 3 in FIG.

  In the configuration shown in FIG. 1 or FIG. 8, the bottom surface of the post 6 and a part or the entire region of the resistance element 8 may be in a state of being overlapped without interposing the insulating substrate 3. In this case, the post 6 and the resistance element 8 are arranged on the same insulating substrate 3 surface. This configuration has an advantage that the sensitivity of the resistance element 8 can be increased. The reason is that the stress applied to the post 6 stimulates the resistance element 2 almost directly by the bottom surface of the post 6 without passing through the insulating substrate 3. As a result of the stimulation, the resistor 2 portion of the resistance element 8 is compressed, and the resistance value, which is a characteristic value, changes greatly. When the stimulus is released, the resistance portion once compressed expands and the resistance value returns.

  As described above, a further advantage of the configuration in which the resistance element 8 is arranged on the same insulating substrate 3 surface and the post 6 is fixed is that the stress sensor of the present invention can be obtained only by the mounting operation on one surface of the insulating substrate 3. It becomes possible to manufacture. The mounting operation includes an operation of placing the resistor 2 and an operation of fixing the post 6 to the surface of the insulating substrate 3 using an adhesive or the like. When mounting on both surfaces of the insulating substrate 3, severe conditions such as cleanliness and softness of the place where the other insulating substrate 3 surface is placed are imposed when mounting on one insulating substrate 3 surface. In that respect, such a severe condition is not imposed as long as it is mounted on the same insulating substrate 3 surface. A further advantage is that the alignment operation between the resistance element 8 and the post 6 is facilitated. The positional relationship between the resistance element 8 and the post 6 is an important factor that affects the performance of the stress sensor.

  For example, in FIG. 8, when the position of the post 6 is largely deviated from the position of the resistance element 8, the transmission method to each resistance element 8 due to the stress applied to the post 6 is different. When the post 6 and the resistance element 8 are mounted on separate surfaces on the insulating substrate 3, if the surface of one insulating substrate 3 is viewed, the other insulating substrate 3 surface cannot be seen. For this reason, it is difficult to grasp the relative positional relationship between the post 6 and the resistance element 8, and their positional deviation is likely to occur. In this respect, if the same insulating substrate 3 is mounted, it is very easy to grasp the relative positional relationship between the post 6 and the resistance element 8, so that the positional deviation is unlikely to occur. In addition, it is easy to perform a visual check when removing the one that has been displaced.

  Further, in the configuration shown in FIG. 1 or FIG. 8, it is preferable to have a protective film covering at least the resistance element 8. The protective layer is a material that is more flexible than the insulating substrate 3. Examples of such materials include silicone resin materials and rubber materials. The flexible material has an effect of suppressing a decrease in adhesion between the insulating substrate 3 and the resistance element 8 due to repeated bending (extension or contraction) of the resistance element 8 following the bending of the insulating substrate 3.

  1 and 8, the material of the post 6 can be selected from those made of metal, ceramic, resin, or fiber reinforced resin. The advantage of using a metal such as iron or high carbon steel or ceramic as the material of the post 6 is that the applied stress can be accurately transmitted to the resistance element 8 due to their rigidity. The first advantage when the resin or the fiber reinforced resin is used as the material of the post 6 is that the energy consumption is small in the production. For example, the temperature at which a resin or fiber reinforced resin is molded and cured is much lower than the sintering temperature of ceramics or the casting temperature of metals. The second advantage is that the moldability is superior to ceramics and metals. For example, when the post 6 having a complicated shape is manufactured, there is a risk that cracks may occur after a ceramic forming / sintering process and a metal casting process. This is because the rigid body is difficult to follow the volume shrinkage accompanying the temperature change from a very high temperature to room temperature during cooling. On the other hand, when using a resin or fiber reinforced resin, the melting temperature of the resin is very low compared to the sintering temperature or casting temperature, and the rigidity of the resin is low compared to metal or ceramic. It can be said that there is hardly any.

  The post 6 can be used when the stress sensor of the present invention is applied to a pointing device for a personal computer, various electronic devices such as a mobile phone, particularly a multifunctional multi-directional switch of a small portable electronic device. Here, when the stress sensor of the present invention is used as the multi-function multi-directional switch, the cross-sectional shape of the side surface of the post 6 is varied in order to enable the operator to recognize in which direction the stress should be applied. It is preferable that each command be transmitted to the electronic device by applying a stress perpendicular to each plane on the side surface of the post 6 in a square shape. In consideration of the complexity of the post 6 shape in the case of such a polygonal cross section, the post 6 is preferably made of resin or fiber reinforced resin as described above.

  As a material in the case of using a resin, polyvinyl terephthalate (PVT) or polybutylene terephthalate (PBT) can be used particularly preferably. Since PVT and PBT are particularly excellent in rigidity among resin-based materials, there is an advantage that applied stress can be transmitted relatively accurately. Moreover, since heat resistance is also favorable, it has the advantage that the rigidity can be maintained even when the usage environment is slightly higher than room temperature.

  In the configuration shown in FIGS. 1 and 8, the material of the insulating substrate 3 can be selected from a resin-based material, a metal whose surface is covered with a non-conductive material, or ceramic. As what has the said resin-type material as a main component, there exist fiber reinforced resin, such as a phenol resin single-piece | unit, a glass fiber mixing epoxy resin molding, etc., for example. Examples of the metal whose surface is coated with the nonconductive material include iron or aluminum plate coated with polyethylene resin. Examples of the ceramic include alumina. The insulating substrate 3 needs to have both rigidity and elasticity capable of restoring its shape when stress is removed with respect to flexibility that can be bent to some extent and multiple bending, and these are exemplified. Any material can satisfy them.

  The reason why the stress sensor of the second configuration uses the resistance element 8 of the first configuration of the present invention as a constituent requirement will be described. The stress sensor of the present invention grasps the direction and magnitude of the stress from the change in the resistance value of the resistance element 8 resulting from the application of stress to the post 6. Therefore, if there is a large difference in the formation state of each resistance element 8, a problem arises in the balance and stability of the output characteristics of the stress sensor. For example, when each resistance element 8 is directly trimmed, if there is a large difference in the length of the trimming groove to be formed, the longer the groove length, the higher the sensitivity. Further, the resistive element 8 having high sensitivity is likely to deviate from the initial resistance value when used for a long period of time. From these facts, it is preferable that the resistance value variation of each resistance element 8 before the trimming groove formation is made as small as possible and the trimming groove length can be made uniform. Therefore, it is a great advantage to use a component having a small variation in resistance value from the beginning as in the case of the resistance element 8 of the present invention. For the same reason, a stress sensor having both the second configuration and any one of the first to first configurations is a more preferable configuration.

  Even if each resistance element 8 is not directly trimmed but is a stress sensor whose resistance value is indirectly adjusted by trimming the trimmable chip resistor 11 as described above, the trimming of the trimmable chip resistor 11 is performed. When the variation in the groove length is large, there is a problem in the balance and stability of the output characteristics of the stress sensor depending on the surrounding environment. For example, when the trimming chip resistor 11 has a long trimming groove length, the resistance value easily changes depending on the ambient temperature. Therefore, even when the resistance value is adjusted by using the trimmable chip resistor 11, it is a great advantage to use a component having a small resistance value variation from the beginning as in the resistance element 8 of the present invention. .

  In the latter case, the resistance value variation of each resistance element 8 directly becomes a variation in output (sensitivity). A specific example will be described in which there are four resistance elements 8 in one stress sensor shown in FIG. Assume that the resistance value of one resistance element A is R, and the resistance value of another resistance element B is R / 2, which is half that of the resistance element A. When the insulating substrate 3 is bent so that the resistance elements A and B are bent by the same amount, if the resistance value of the resistance element A is doubled, the resistance value of the resistance element B is also doubled. As a result, the resistance value of the resistance element A is 2 × R, and the resistance value of the resistance element B is R. Therefore, the resistance value change amount of the resistance element A is R, and the resistance value change amount of the resistance element B is R / 2. When the same stress is applied to resistance elements having different resistance values in this way, the resistance value change rate is the same, but the resistance value change amount is two times different. Usually, a stress sensor using a resistance element as a strain gauge outputs a resistance value change amount as a magnitude of stress. Therefore, it is a great advantage to use a component having a small variation in resistance value from the beginning as in the case of the resistance element 8 of the present invention.

  The third stress sensor of the present invention for solving the above problems is obtained by removing a part of the conductor layer on the surface and obtaining it as the remainder, or the conductor 9 on the surface of the insulating substrate 3 obtained by the additive method. The resistive element 8 is arranged on the surface of the insulating substrate 3 having a post, and the post 6 is fixed or integrated on one surface of the insulating substrate 3, and the resistance value of the resistive element 8 due to the stress applied to the post 6 is changed. A stress sensor for grasping the direction and magnitude of the stress, wherein the resistance element 8 is formed in a thick film between the resistance element 8 electrode formed in a film so as to be electrically connected to the conductor 9 and the resistance element 8 electrode. It consists of the resistor 2, and the resistor 2 is mainly in contact with the flat portion of the electrode for the resistor element 8.

  By having the third configuration, the electrode constituting the resistance element 8 has a high height (first reason) and has a surface substantially perpendicular to the surface of the insulating substrate 3 (second Reasons), these two reasons can not be included in the configuration of the present invention, whereby the resistance value variation of the resistance element 8 can be reduced.

  Since the thick film electrode 13 by the screen printing method or the like in FIG. 10 does not have the first reason and the second reason on the contact surface with the resistor 2 (FIG. 10B), the thick film electrode 13 is used. The resistance element 8 has a small variation in resistance value. However, in order to further reduce the resistance value variation, the resistor 2 is mainly in contact with the flat portion of the electrode for the resistive element 8 (thick film electrode 13). This reason is to avoid the influence of the first reason. For example, in FIG. 10B, the thick film electrode 13 in the vicinity of the conductor 9 has the surface substantially perpendicular to the insulating substrate 3. This is because it is not preferable to bring the resistor 2 and the conductor 9 close enough to bring the resistor 2 into contact with the substantially vertical surface, which includes the first reason described above.

  FIG. 11 is an explanatory diagram for clarifying the meaning of the flat portion to some extent. The thick film electrode 13 which is a resistor element electrode is divided into a, b, and c cross-sectional areas. The region a is substantially similar to the outer shape of the conductor 9, and when the resistor 2 is disposed in this region, the resistance element 8 including the first and second reasons described above is obtained. The region b is a substantially flat portion, and the height from the surface of the insulating substrate 3 is about 10 μm obtained by normal thick film printing (screen printing or the like). Therefore, when the resistor 2 is disposed in this region, the resistor element 8 having the above-described first and second reasons is obtained. In the region c, the outer shape of the thick film electrode 13 is not flat, but the height from the surface of the insulating substrate 3 is less than 10 μm and has a gentle slope. Therefore, when the resistor 2 is disposed in this region, the resistor element 8 having the above-described first and second reasons is obtained. In the present invention, “mainly the flat portion of the resistor element electrode” refers to the region b and the region c in FIG.

  Further, depending on the paste properties of the resistor 2 paste used, the region a is not a surface perpendicular to the surface of the insulating substrate 3 as shown in FIG. May include major faces. In such a case, the regions that are substantially flat and do not have the first and second reasons described above are the regions b and c. At present, by setting the shortest distance between the conductor 9 and the resistor 2 to be approximately equal to or greater than the height of the conductor 9, the resistive element 8 that does not have the first and second reasons described above is obtained empirically. I know that I can.

  Thus, by setting the shortest distance between the conductor 9 and the resistor 2 to be a predetermined distance (the height of the conductor 9) or more, when the resistor 2 film is formed by the screen printing method as described above, the conductor 9 Variations in the amount of paste resistor due to the collision between the squeegee and the position of the paste resistor can be reduced, and the shape of the resistor 2 formed between the conductors 9 can be stabilized. This is because the position where the squeegee collides with the conductor 9 and the position where the paste resistor is actually disposed are separated. Here, when the thick film electrode 13 is arranged by the screen printing method, the squeegee is affected by the collision with the conductor 9, but the influence is mainly in the vicinity of the conductor 9, and in the vicinity of the contact portion with the resistor 2. It is hard to receive. The reason is that the formation of the thick film electrode 13 in the vicinity of the contact portion is the formation of the thick film electrode 13 at a position more than the shortest distance between the resistor 2 and the conductor 9, and the resistor 2 film described above is formed. This is because there is a reason similar to the reason that it is difficult to be affected by the above. Even if there is some variation in the connection state between the conductor 9 and the thick film electrode 13, the resistance value variation of the resistance element 8 is hardly affected due to the low specific resistance.

  Another advantage of forming both the resistor 2 and the thick film electrode 13 constituting the resistance element 8 as a strain gauge for a stress sensor is that their adhesion strength is high. The adhesion between the conductor 9 and the resistor 2 is low, and when a stress is applied many times to the interface between the conductor 9 and the resistor 2 during the stress sensor operation, the possibility of peeling at the interface cannot be denied. On the other hand, it is considered that the interface between the resistor 2 and the thick film electrode 13 is not likely to be peeled off even if a normal stress sensor is used for a long time. The resistor 2 and the thick film electrode 13 mentioned here include both a metal glaze material and a resin material. In particular, when both the resistor 2 and the thick film electrode 13 are made of a resin-based material, the adhesiveness at the interface, the followability to the stress applied due to the elasticity of the resin, and the resilience when the stress is released Therefore, it can be said that it is suitable as a constituent material of the resistance element 8 as a strain gauge for a stress sensor as compared with other material systems.

  In the configuration of the resistor element, when the conductors 9 on both surfaces of the insulating substrate 3 are electrically connected through the conductive material in the through hole, the height of the conductor 9 may be higher than usual. preferable. The reason why the height of the conductor 9 may be increased is that a so-called double-sided wiring board manufacturing process includes an electroless plating process in order to form a conductive layer on the inner wall of the through hole of the insulating substrate 3 and to connect the wirings on both sides. In this case, the electroless plating layer is also formed on the portion that becomes the conductor 9.

  For example, as shown in FIG. 8, the stress sensor of the third configuration is on two orthogonal straight lines along the surface of the insulating substrate 3 with the center of the sensor effective area of the surface of the insulating substrate 3 constituting the resistance element 8 as an intersection. In addition, the resistance element 8 is disposed at a substantially equidistant position from the intersection, and the post 6 is fixed or integrated with the surface of the insulating substrate 3 so that the center of the surface of the insulating substrate 3 and the center of the bottom surface of the post 6 substantially coincide with each other. Then, the direction and strength of the stress are grasped from a change in resistance value due to expansion, contraction, or compression of the resistance element 8 resulting from the application of stress to the post 6.

  An example of the stress sensor having the third configuration will be described with reference to FIG. Here, the conductor 9 in contact with the resistor 2 in FIG. 8, that is, the circuit pattern electrode 1, replaces the thick film electrode 13. The insulating substrate 3 is made of, for example, an epoxy resin plate mixed with glass fiber. Four pairs of thick film electrodes 13 are provided on the lower surface of the insulating substrate 3 so as to be electrically connected to the conductor 9, and the resistor 2 is disposed between each pair of thick film electrodes 13. Is configured. The resistance elements 8 are arranged on two perpendicular lines along the surface of the insulating substrate 3 with the center of the surface of the insulating substrate 3 as an intersection, and at substantially equidistant positions from the intersection. A post 6 having a substantially square bottom surface is fixed to the upper surface of the insulating substrate 3 with an adhesive or the like. At this time, the center of the bottom surface of the post 6 is made to substantially coincide with the center of the surface of the insulating substrate 3. Further, an L-shaped hole 10 is provided in the insulating substrate 3 such that the L-shaped corner is directed toward the center of the insulating substrate 3. The role of the hole 10 is as described for the stress sensor of the second configuration described above.

  The advantage that the trimmable chip resistors 11 connected in series with the respective resistance elements 8 are arranged on the upper surface of the insulating substrate 3 is omitted because it overlaps with the description of the second configuration.

  The “center” in the “center of the sensor effective region” and “center of the bottom surface of the post 6” does not indicate the exact center point, but includes a deviation from the center point in a range where the stress sensor functions effectively. . The meanings of the terms used in the description of the stress sensor of the other third configuration are the same as those of the stress sensor of the first configuration or the second configuration. Needless to say, the configurations of 1a to 1d and the combination of the second configuration and the third configuration are not denied. Rather, the advantages of these configurations are added, which is more preferable.

  Also in the configuration of the third stress sensor shown in FIG. 8, the hole 10, the support hole 12, and the trimmable chip resistor 11 are optional components (not essential) for the stress sensor of the present invention. Even if these are included in the configuration requirements, the shape of the hole 10 is not limited to the L shape, and the arrangement of the support holes 12 is not limited to the four corners of the insulating substrate 3 having a rectangular outer shape. The shape of the hole 10 can be changed as appropriate according to restrictions on design of the stress sensor, required functions, applications, etc., for example, a circle, a rectangle, a rounded rectangle, and the like. Further, the support hole 12 can be arranged near the middle of each side of the end portion of the rectangular insulating substrate 3 in FIG.

  The stress sensor having the third configuration shown in FIG. 8 may have a configuration in which the bottom surface of the post 6 and a part or the entire area of the resistance element 8 overlap with each other without the insulating substrate 3 interposed therebetween. The advantage in this case is the same as the advantage obtained by the similar configuration in the stress sensor of the second configuration. For the same reason as the stress sensor of the second configuration, it is preferable that the third configuration shown in FIG. 8 has a protective film covering at least the resistance element 8. The stress sensor of the third configuration is the same as the stress sensor of the second configuration in that the resistance element 8 has a small variation in resistance value from the beginning of the formation.

  The second configuration of the resistance element 8 of the present invention for solving the above problem is obtained by removing a part of the conductor layer on the surface and obtaining it as the remainder or on the surface of the insulating substrate 3 obtained by the additive method. A part of the conductor 9 is used as an electrode, and the resistor 2 is formed between the pair of circuit pattern electrodes 1 on the surface of the insulating substrate 3, and the resistor 2 has the width of the pair of circuit pattern electrodes 1. It is characterized by covering both ends in the direction. Here, the electrode width direction is a direction orthogonal to the current traveling direction when the resistance element 8 is energized and along the surface of the insulating substrate 3.

  By having the second configuration of the resistance element 8 of the present invention described above, it is possible to reduce the occurrence of the bleeding 14 shown in FIG. The blot 14 is made of the resistor 2 and is in contact with the circuit pattern electrode 1 and is electrically connected to the other opposing electrode, so that the resistance value of the resistance element 8 is affected. The degree of the influence is an uncertain factor depending on the amount and shape of the blur 14. This is because it is extremely difficult to control the amount of bleeding 14 and its shape as described above. Therefore, by substantially eliminating the uncertain factor as in the configuration of the present invention, a part of the conductor layer on the surface is removed, and a part of the conductor 9 obtained as the remaining part is used as an electrode, and the surface of the insulating substrate 3 Also in the resistance element 8 having the resistor 2 formed between the pair of electrodes, the variation in resistance value can be reduced.

  The reason why the bleeding 14 is more likely to occur when the circuit pattern electrode 1 is used as compared with the case where the thick film electrode 13 is used will be described. As described above, the main reason is that the height of the circuit pattern electrode 1 is high and the circuit pattern electrode 1 has a surface substantially perpendicular to the surface of the insulating substrate 3. That is, taking a case where a thick film resistor is formed by a screen printing method as an example, a substantially constant amount of paste-like resistor is first disposed between the pair of circuit pattern electrodes 1 through a mask. Then, the periphery of the circuit pattern electrode 1 becomes a free flowing region of the resistance paste. This is because the paste near the top surface of the circuit pattern electrode 1 is likely to move along the substantially vertical plane from a high place to a low place due to its own weight. Due to this ease of movement, the amount of movement becomes excessive, and the excess becomes the blur 14.

  In the conventional resistance element 8 shown in FIG. 12B, the thickness of the thick film electrode 13 is low, and the thick film electrode 13 has a smooth surface from the surface of the insulating substrate 3, so that the surface is It does not become a free-flowing region of the paste-like resistor, and is a condition in which bleeding 14 is unlikely to occur.

  Next, it will be described whether or not the uncertain factor can be eliminated by having the second configuration of the resistance element 8 of the present invention. FIG. 13 shows an example of the resistance element 8 of the present invention. The cross section of the resistance element 8 is considered to have substantially the same form as the cross section shown in FIG. However, as shown in FIG. 13, if the paste-like resistor 2 is placed in a portion where the bleeding 14 (FIG. 12A) will occur in advance, the high place due to the weight of the paste in the free-flowing region is assumed. Even if the movement along the substantially vertical plane from the low point to the low part occurs, the excessive movement amount is mixed with the resistor 2 paste that is offshore from the surface of the circuit pattern electrode 1. Since the amount of the resistor 2 paste applied to the bleeding 14 is very small, even if the resistor 2 paste is mixed with the offshore resistor 2 paste, the change in the resistance value is negligible, which may be the above-mentioned uncertain factor. Absent. The blur 14 in FIG. 12A is a small amount, but has a high current density when energized, and is a factor that increases the area of the resistor 2 / circuit pattern electrode 1 interface between the opposing resistance element electrodes. The degree of influence on the resistance value was large, and this was an uncertain factor. Thus, it has become clear that the uncertain factor can be eliminated by having the configuration of the present invention.

  In the second configuration of the resistance element 8 of the present invention, the circuit pattern on both surfaces of the insulating substrate 3 is electrically connected via the conductive material in the through hole, and a part of the conductor 9 on the surface of the insulating substrate 3 is used as an electrode. When the resistor 2 is formed between the pair of electrodes on the surface of the insulating substrate 3, the electrode height may be higher than usual, and the application of the present invention is particularly preferable. The reason why the electrode height may be increased is that in the so-called double-sided wiring board manufacturing process, an electroless plating process is required in order to form a conductive layer on the inner wall of the through hole of the insulating substrate 3 and make the wiring on both sides conductive. In this case, the electroless plating layer is also formed on the portion that becomes the circuit pattern electrode 1.

  The stress sensor of the fourth configuration of the present invention uses the resistance element 8 in the above-described second configuration of the present invention or a preferable configuration based on it as a strain gauge, and posts it on one surface of the insulating substrate 3. 6 is fixed or integrated, and the direction and the magnitude of the stress are grasped by a change in resistance value of the resistance element 8 caused by the application of stress to the post 6.

  For example, as shown in FIG. 1 and FIG. 8, the stress sensor is formed on two orthogonal straight lines along the surface of the insulating substrate 3 with the center of the sensor effective area of the surface of the insulating substrate 3 constituting the resistance element 8 as an intersection. In addition, the resistance element 8 is disposed at a substantially equidistant position from the intersection, and the post 6 is fixed or integrated with the surface of the insulating substrate 3 so that the center of the surface of the insulating substrate 3 and the center of the bottom surface of the post 6 substantially coincide. The direction and strength of the stress are grasped from the change in resistance value caused by the expansion, contraction, or compression of the resistance element 8 caused by the application of stress to the post 6.

  The operation and advantage of the stress sensor of the fourth configuration are the same as those of the third stress sensor. Further, for example, an application form similar to the third form such as using a trimmable chip resistor 11 can be adopted. The meanings of the terms used in the description of the stress sensor having the fourth configuration are the same as those of the stress sensors having the configurations of 1a to 1d or 2nd and 3a. Needless to say, the configurations of 1a to 1d and the combination of the second, third, and fourth configurations are not denied. Rather, the advantages of these configurations are added, which is more preferable.

  According to the present invention, a part of the conductor layer on the surface is removed, a part of the conductor obtained as the remainder is used as an electrode, and the resistor has a resistor formed as a film between the pair of electrodes on the insulating substrate surface. Also in the element, variation in resistance value could be reduced. Moreover, the stress sensor using the resistance element which reduced such resistance value dispersion | variation was able to be provided.

  The stress sensor can be suitably used for a pointing device for a personal computer, a multifunctional / multidirectional switch for various electronic devices, and the like.

  In addition, the stress sensor can be particularly suitably applied to a stress sensor that uses a substrate in which a glass fiber-mixed epoxy resin is formed into a plate shape and can achieve cost reduction as compared with the conventional case.

  Hereinafter, an example of an embodiment of a stress sensor having a configuration of 1a to 1d of the present invention in which a glass fiber-containing epoxy resin molded body is a substrate (thickness: 1.2 mm) will be described with reference to the drawings.

  First, a copper foil having a thickness of 18 μm is pasted on both surfaces of the insulating substrate 3 and then a known etching process is performed except for a necessary portion of the copper foil, whereby a conductor 9, a resistor element electrode (circuit pattern electrode 1), and a substrate terminal Part 5 is formed. The layout of the conductor 9 and the resistor element electrode on the surface of the insulating substrate 3 in the unit stress sensor thus obtained is shown in FIG. Here, only the side on which the resistance element is disposed is shown, but the back surface of the insulating substrate 3 also has a conductor wiring.

  Here, on the surface of the insulating substrate 3, the conductor 9 (printing accuracy adjusting member 7) that does not contribute to the wiring by the etching process is left. Due to the presence of the printing accuracy adjusting member 7, the arrangement of the conductor 9, the resistor element electrode and the printing accuracy adjusting member 7 in the vicinity of all the four resistance elements 8 is similar. Further, for all four resistance elements 8, the arrangement of the conductor 9, the resistance element electrodes, and the printing accuracy adjusting member 7 in the vicinity thereof surrounds the three sides of the resistor 2.

  Next, the conductors on the front and back surfaces of the insulating substrate are made conductive by disposing a conductive substance on the inner wall of a through hole provided in advance in the insulating substrate 3 by electroless plating. In FIG. 1, this portion is shown as a “through hole portion”. At this time, the conductive material deposited by electroless plating also deposits on the conductor 9, the resistor element electrode, and the surface of the printing accuracy adjusting member 7, thereby each of the conductor 9, the resistor element electrode, and the printing accuracy adjusting member 7. The height of becomes a substantially constant value of 30 to 50 μm.

  Thereafter, a carbon resin-based resistor paste is disposed between the resistance element electrodes (circuit pattern electrodes 1) by screen printing. The squeegee traveling direction at this time was set to a direction of about 45 ° obliquely with respect to the insulating substrate 3 in FIG. And the said resin is thermosetted and the resistor 2 is obtained. Further, in order to protect the resistor 2, a protective film made of a silicone resin (not shown) is arranged by screen printing so as to cover at least the resistance element, and is thermally cured.

  Thereafter, a columnar post 6 having a square bottom surface is fixed to the back surface of the insulating substrate 3 with an epoxy resin adhesive. At this time, each side of the square on the bottom surface (the contour of the bottom surface of the post 6) is set to a position corresponding to the resistance element on the surface of the insulating substrate 3.

  Further, trimmable chip resistors (R1 trim to R4 trim) electrically connected in series with the respective resistance elements (R1 to R4) are mounted on the back surface of the insulating substrate 3 so as to be in the electrical connection state shown in FIG. The mounting is performed by employing a known electronic component mounting technique. After that, the resistance value is adjusted by laser trimming to the trimmable chip resistors so that the sum of the resistance values of the respective resistors and the trimmable chip resistors connected in series with each other is set to be substantially the same. carry out. The set is composed of corresponding numbers such as R1 and R1trim.

  Thus, the stress sensor of the present invention can be obtained. This stress sensor is usually used by fixing the four corners of the end portion of the insulating substrate 3, particularly when the insulating substrate 3 is a quadrangle. FIG. 3 shows an outline of the operation when lateral stress is applied to the post 6 in the use state. The insulating substrate 3 in contact with the bottom surface of the post 6 hardly bends, and the vicinity of the contour of the bottom surface of the post 6 is set as the maximum deflection region, and the outside is slightly bent.

  FIG. 4 also shows an outline of the state of electric signal input / output in the stress sensor of the present invention. Four sets of resistance elements and the trimmable chip resistor 11 constitute a bridge circuit. A predetermined voltage is applied between the voltage application terminals (Vcc) and (GND) of the bridge circuit. Further, a stress sensor in the Y-axis direction is configured by the resistance element on the left side of the figure, the trimmable chip resistor, and the Y terminal (Yout), and further, the resistance element, the trimmable chip resistor, and the X terminal (Xout) on the right side of the figure. A stress sensor in the X-axis direction is configured.

  FIG. 5 shows a surface layout of the insulating substrate 3 of a stress sensor (hereinafter referred to as stress sensor B) that is not of the present invention. Here, the printing accuracy adjusting member 7 as shown in FIG. 1 does not exist. Further, in all four resistance elements 8, the arrangement of the conductor 9 and the resistance element electrodes (circuit pattern electrodes 1) in the vicinity thereof is not the same or similar. Further, regarding two of the four resistance elements, the arrangement of the conductor 9 and the electrode for the resistance element in the vicinity thereof is not set to surround three sides of the periphery of the resistor 2.

(Experiment)
A comparative experiment between the stress sensor of the present invention and the stress sensor B was performed. Both have the same manufacturing conditions other than the surface layout of the insulating substrate 3. The experiment (evaluation) item is a resistance value variation of each resistance element after the resistance element is formed. When the variation of the resistance value of each of the number of the stress sensors, that is, the number of the resistance elements of 120, is represented by the standard deviation, the stress sensor of the present invention is 41.5Ω, whereas the stress sensor B is 57. It was 3Ω. Moreover, in the stress sensor of the present invention, there was almost no variation in the shape of each resistor within one stress sensor, whereas in the stress sensor B, the variation in each resistance value within one stress sensor was the standard deviation. It had the same degree of variation. From this, it is clear that the variation of each resistor shape within one stress sensor could be suppressed.

  Next, referring to the drawings (particularly FIG. 8), examples of embodiments of the resistance element having the first configuration and the stress sensor having the second configuration according to the present invention will be described.

  A double-sided copper-clad laminate is prepared in which a copper foil as a conductor layer having a thickness of about 18 μm is disposed on both sides of a 0.8 mm-thick laminate having a glass fiber-mixed epoxy resin as a main component. This double-sided copper-clad laminate has an insulating substrate 3 having a substantially square outer shape as a unit as shown in FIG. The element 8 and the trimmable chip resistor 11 are patterned over the front and back of the insulating substrate 3 so as to be in an electrical connection state as shown in FIG. In the first step of the patterning, a portion necessary for forming a conductive path over the front and back of the double-sided copper clad laminate is punched. In the second step, a conductor is formed on the inner wall of the through hole that has been drilled, and electroless copper plating and electrolytic copper plating are applied in this order for the purpose of conducting the copper foils on the front and back sides. At this time, copper by plating also adheres to the copper foils on both sides of the substrate, and the total thickness of copper on both sides of the substrate becomes about 50 μm. In the third and subsequent steps, a portion of the conductor layer on the surface is removed by a photoetching method using a known dry film resist. As the remainder, wiring 7 and circuit pattern electrode 1 are obtained. The distance (L) between the pair of circuit pattern electrodes 1 after these steps is 1.2 mm. Therefore, the ratio L / h is 24.

  Next, the obtained large insulating substrate is roll-pressed and adjusted so that the height of the circuit pattern electrode 1 is 30 μm. This gives a ratio L / h of 40. Then, a hole 10 shown in FIG. 8 is formed by punching for each of the one unit of the insulating substrate 3.

  Thereafter, a resistor paste of a thermosetting resin type (carbon resin type) is formed between the circuit pattern electrodes 1 by screen printing and cured by heating to form the resistor 2. Further, in order to protect the resistor 2, a silicone resin paste is screen-printed, and then the paste is cured to form a protective film. Thus, the resistance element 8 having the first configuration of the present invention is obtained.

  Next, a known mounting technique and reflow technique are used so that the trimmable chip resistor 11 electrically connected by wiring in series with each of the resistor elements 8 is connected to the resistor 2 as shown in FIG. It distributes by. Further, as shown in FIG. 8, the trimmable chip resistor 11 is disposed on the surface opposite to the surface on which the resistance element 8 of the substrate 4 is disposed, and on the non-deformation portion described above.

  Thereafter, laser trimming is performed on the trimmable chip resistor 11 in order to adjust the sum of the resistance values of the resistive element 8 and the trimmable chip resistor 11 electrically connected in series with each resistive element 8 to a predetermined range. . The reason why the resistor 2 constituting the direct resistance element 8 is not trimmed is that the resistor 2 made of resin and the substrate 4 on which the resistor 2 is arranged and the resin 4 as a main component are trimmed. This is because prevention of instability of the resistance value due to the application is taken into consideration. These resins behave unstablely to very high temperature processing such as laser trimming.

  Whether or not the trimmable chip resistor 11 should be used should be determined based on the material of each member constituting the resistance element 8 and the material of the insulating substrate 3. For example, when the material of the insulating substrate 3 is ceramic and the material of the resistor 2 is metal glaze, even if the resistor 2 constituting the resistor element 8 is directly subjected to laser trimming, the subsequent resistance Inconveniences such as destabilization of values are negligible. Therefore, in such a case, the trimmable chip resistor 11 may not be used. However, when there are other causes, and it is necessary to use the trimmable chip resistor 11, it is needless to say that it should be used as necessary.

  As shown in FIG. 8, for each unit of insulating substrate 3, the PBT molded post 6 having a square bottom surface outline and the surface on which the resistance element 8 of the insulating substrate 3 is disposed on the bottom surface. It fixes with an epoxy-type adhesive so that it may contact | abut on an opposite surface and the center of the bottom face may correspond with the center of each 1 unit of insulation board | substrate 3 substantially. Thus, an assembly of the stress sensor of the present invention is obtained.

  Next, the large insulating substrate is cut with a disk cutter along a large number of dividing lines (visible lines or invisible lines) provided vertically and horizontally on the large insulating substrate surface so as to become one unit of insulating substrate 3 each. -Divide into individual stress sensors. By fixing the post 6 before division as in this example, the workability is improved. The reason is that the work of attaching the post 6 to the insulating substrate 3 having each stress sensor after being divided into individual stress sensors is inferior in handling and handling as compared with the work for a large insulating substrate, and is complicated. It is.

  When the large insulating substrate is made of ceramic such as alumina, it is preferable to use a large insulating substrate in which a number of dividing grooves are formed in advance in the vertical and horizontal directions. The reason is that even if a disk cutter is not used, the dividing operation can be easily performed by applying force by hand or the like so as to open the dividing groove.

  The stress sensor of the present invention is used, for example, by fixing the stress sensor to a housing or the like of an electronic device through a support hole 12 shown in FIG. Then, in the fixed state, the peripheral edge portion of the insulating substrate 3 outside the hole 10 becomes a non-deformed portion that hardly deforms even when stress is applied to the post 6, and the inside of the hole 10 is deformed when stress is applied to the post 6, and resistance It becomes a deformation part which expands and contracts the element 8. The deformed portion becomes a “sensor effective region” on the surface of the insulating substrate 3.

  FIG. 4 shows an outline of the state of electric signal input / output in the stress sensor of the second configuration. This is the same as the stress sensor having the above-described configurations 1a to 1d.

  Here, in the state where the stress sensor is fixed to the housing, when there is a gap on the lower surface of the stress sensor, it is possible to detect that the post 6 is stressed downward (Z direction). The reason is that by applying stress downward, all four resistance elements, which are strain gauges, can be stretched, and the respective resistance values can be increased to substantially the same level. Such electrical characteristics are different from those in the case where stress is applied in the lateral direction (X direction, Y direction), and can be distinguished from these.

  In the stress sensor, by adding some function to applying stress downward (Z direction), multiple functions can be achieved. For example, when the stress sensor of the present invention is used as a pointing device of a computer, a so-called mouse click function can correspond to the downward stress application. Further, when the stress sensor of the present invention is used as a multi-function / multi-directional switch for a small portable device such as a so-called mobile phone, for example, when the stress is applied downward for a predetermined time, the power of the portable device is turned on.・ It is possible to correspond to an off command.

  In this example, a photo-etching method using a dry film resist is employed to remove a part of the copper foil that is a conductor layer on the surface. Instead, a so-called ED (Electro Deposition) in which a photo-resist is applied by electrophoresis. The law can be adopted. In addition, as a means for forming the conductor 9 and the circuit pattern electrode 1 in FIG. 8, the surface of the insulating substrate 3 (including the inner wall surface of the through hole) is not subjected to a removal process, but electroless plating is performed on the surface of the insulating substrate 3. Needless to say, a so-called additive method of growing and patterning the substrate can be employed.

  Next, referring to the drawings, examples of embodiments of the resistance element having the second configuration and the stress sensor having the fourth configuration according to the present invention will be described.

  The formation process of the insulating substrate 3 and the circuit pattern electrode 1 made of the glass fiber mixed epoxy resin molding until the resistor is formed by screen printing is the same as that of the embodiment of the resistor element of the second configuration. . When the thermosetting resin-based (carbon resin-based) resistor paste is formed and heat-cured between the circuit pattern electrodes 1 by screen printing to form the resistor 2, the width of the circuit pattern electrode 1 is 1.2 mm. The width of the resistor 2 is set to 1.6 mm, and the resistor 2 covers both ends of the circuit pattern electrode 1 in the width direction as shown in FIG. Here, the entire upper surface of the circuit pattern electrode 1 is covered with the resistor 2. The protruding distance from the circuit pattern electrode 1 of the resistor 2 on the conductor 9 (FIG. 8) side of the circuit pattern electrode 1 was about 0.2 mm.

  Thereafter, in order to protect the resistor 2, a silicone resin paste is screen-printed, and then the paste is cured to form a protective film. Thus, the resistance element 8 having the second configuration of the present invention can be obtained.

  The subsequent process up to the construction of the stress sensor is the same as that of the stress sensor of the second configuration, and the stress sensor of the third configuration of the present invention can be obtained.

  In this example, it goes without saying that the ED method or the additive method can be adopted instead of the photoetching method using the dry film resist.

  FIG. 14 shows another example of the form of the resistance element 8 of the present invention. Here, as shown in FIG. 13, the circuit pattern electrode 1 as viewed from above is not covered at both ends in the width direction, but is covered by leaving part of both ends of the circuit pattern electrode 1 in the width direction. In this case, the blur 14 is generated at a different location from that in FIG. 12A by the same mechanism as in FIG. Even if the blur 14 whose amount and shape are difficult to control is generated at the location, the influence on the resistance value of the resistance element 8 is negligible. The reason for this is that the blur 14 here is a trivial uncertain factor in a region other than the resistor 2 region (region having the highest current density) opposed to the paired circuit pattern electrodes 1. Therefore, the resistive element 8 shown in FIG. 5 solves the problem to be solved by the present invention, and can be said to be an example of the form of the resistive element 8 of the present invention.

  Next, an example of an embodiment of a stress sensor having a third configuration according to the present invention will be described with reference to the drawings.

  The formation process of the substrate and the circuit pattern made of the glass fiber mixed epoxy resin molding until the resistor is formed by screen printing is the same as that of the embodiment of the resistor element having the second and third configurations. However, the circuit pattern electrode 1 is not formed, and instead, a thick film electrode is formed as follows.

  A thermosetting resin-based (silver / resin-based) conductive paste is formed by screen printing / heat curing as the thick film electrode 13 in contact with the circuit pattern as shown in FIG. Further, a resistor paste of a thermosetting resin (carbon / resin) is formed between the thick film electrodes 13 to be paired and heat-cured to form the resistor 2. At this time, the thick film electrode 13 and the resistor 2 are brought into contact with each other in the regions b and c as shown in FIG. Further, in order to protect the resistor 2, a silicone resin paste is screen-printed, and then the paste is cured to form a protective film.

  Until the subsequent stress sensor is configured, the stress sensor having the fourth configuration of the present invention can be obtained through the same process as the stress sensors having the second and third configurations.

  In this example, the thick film electrode 13 is used as the electrode for the resistance element 8, but instead, the electrode for the resistance element 8 may be formed by thin film technology such as sputtering, vapor deposition, or plating. When the formation thickness is in a common sense range (several μm), the resistance element 8 that does not have the first and second reasons described above can be obtained, and the problem to be solved by the present invention can be solved. In particular, when the insulating substrate 3 has a step of copper plating the inner wall of the through hole as in this example, the electrode for the resistance element 8 can be formed at the same time. Therefore, it is considered preferable in that the stress sensor of the present invention can be obtained without going through the thick film electrode 13 forming step as in this example.

  The present invention has industrial applicability to resistance elements and stress sensors that can be used in, for example, pointing devices for personal computers and multifunction / multidirectional switches for various electronic devices.

It is a figure which shows an example of the conductor 9 layout of the stress sensor which concerns on this invention. (A) is a side schematic diagram showing a screen printing process. (B) is a schematic side view illustrating a screen printing process when the angle is changed from the gap between the screen and the substrate in (a). It is a figure of an example which shows the mode of operation | movement of the stress sensor of this invention. It is a figure which shows an example of the outline | summary of the state of an electrical signal input / output in the stress sensor of this invention. It is a figure which shows an example of the conductor 9 layout of the stress sensor which is not this invention. It is a figure explaining the "one end" in this invention. (A) is resistance element sectional drawing comprised by a circuit pattern electrode, (b) is resistance element sectional drawing comprised by the thick film electrode. FIG. 8 is a diagram showing an example of an embodiment of the stress sensor of the present invention. It is a figure which shows the dimension measurement position of the distance (L) between electrodes and the said electrode height (h). (A) is a top view of the resistance element which comprises the stress sensor of the 3rd structure of this invention, (b) is a side view. It is a figure explaining the principal part of the stress sensor of the 3rd structure of this invention. It is a figure explaining generation | occurrence | production of the blur of the resistor in a resistance element. It is a top view of the resistance element of the 2nd composition of the present invention which constitutes the stress sensor of the 4th composition of the present invention. It is a top view of the resistance element of the 2nd composition of the present invention which constitutes the stress sensor of the 4th composition of the present invention. It is a figure which shows the layout of the conductor 9 grade | etc., Of the conventional stress sensor.

Explanation of symbols

1. Circuit pattern electrode 3. Resistor 4. Insulating substrate Board terminal part 6. Post 7. 7. Printing accuracy adjustment member Resistance element 9. Conductor 10. Hole 11. Trimmable chip resistor 12. Support hole 13. Thick film electrode 14. Bleeding 20. Substrate 22. Resistance element 24. Board terminal part 30. post

Claims (2)

A stress sensor in which a post is fixed to or integrated with an insulating substrate surface, and the direction and magnitude of the stress can be grasped from a change in resistance value of the resistance element due to stimulation of a plurality of resistance elements caused by applying stress to the post In
The resistance element is composed of a resistor formed by a screen printing method between a pair of resistance element electrodes arranged on the insulating substrate surface,
The resistor element electrode is connected by a conductor to a substrate terminal portion disposed at one end of the insulating substrate,
The resistance element electrode, the conductor, and the printing accuracy adjusting member have a predetermined height from the insulating substrate surface,
For all of the plurality of resistance elements, the arrangement of the conductor, the printing accuracy adjusting member and the resistance element electrode surrounds three or more sides of a single resistor,
A stress sensor, wherein the resistor is a carbon resin-based resistor. The stress sensor according to claim 1, wherein the insulating substrate is mainly composed of glass fiber mixed epoxy resin.

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