pressure sensor

Abstract

To provide a pressure sensor that exhibits characteristics such as resistance not changing with only weak pressure, or resistance decreasing relatively slowly in response to the applied pressure. [Solution] The pressure sensor 1-1 comprises a pressure detection substrate 50 on which a pressure sensor 20 whose resistance value changes according to the pressing force is provided on a substrate 10, a sheet-like spacer 70 which is thicker than the thickness of the pressure sensor 20 and has a pressure sensor exposed portion 71, and is installed on the pressure detection substrate 50 at a position around the pressure sensor 20, a sheet-like pressing member 90 which is stretched across the spacer 70 with a gap S1 between it and the pressure sensor 20 to isolate it, a highly flexible cushioning member 110, and a hard pressing operation member 130. The pressing operation member 130 applies a load from above to the flexible portion 91 of the pressing member 90 located directly above the pressure sensor 20, causing it to descend by the gap S1 between the pressure sensor 20 and the pressing member 90, making contact with the pressure sensor 20, and further pressing to change the resistance value.

Description

Technical Field

[0001] The present invention relates to a pressure sensor suitable for use in measuring an applied pressure.

Background Art

[0002] Conventionally, among pressure sensors, there is a pressure sensor having a structure in which a pressing member for pressing a pressure-sensitive sensor is installed on a pressure-sensitive sensor whose resistance value changes according to a pressing force.

[0003] FIG. 19 is a schematic cross-sectional view showing an example of this type of conventional pressure sensor 200. The pressure sensor 200 shown in the figure is configured by installing a pressing operation member 270 on the upper part of a pressure detection substrate 250 configured by providing a pressure-sensitive sensor 230 whose resistance value changes according to a pressing force on a substrate 210. The pressing operation member 270 may be, for example, an operation knob or a finger.

[0004] FIG. 20 is a schematic cross-sectional view of a main part of the pressure detection substrate 250 (schematic cross-sectional view taken along the line X-X in FIG. 21), and FIG. 21 is a plan view of the main part of the pressure detection substrate 250. As shown in these figures, the pressure-sensitive sensor 230 forms a first contact pattern 231 and a first wiring pattern 233 connected to the first contact pattern 231 on the substrate 210, forms a pressure-sensitive resistor 235 whose resistance value changes according to pressure on the first contact pattern 231, forms a second contact pattern 237 at a position facing the first contact pattern 231 on the pressure-sensitive resistor 235, and further forms a second wiring pattern 239 connected to the second contact pattern 237 so as to be drawn out onto the substrate 210 after contacting the upper surface and side surface of the pressure-sensitive resistor 235.

[0005] Then, when the pressing operation member 270 shown in Figure 19 is lowered and brought into contact with the upper surface of the pressure sensor 230, and pressed with a predetermined force, the pressure-sensitive resistor 235 is pressed and its thickness is reduced, the resistance value of the thinned portion decreases, and the resistance value between the first and second wiring patterns 233 and 239 drawn from the opposing first and second contact patterns 231 and 237 decreases, and the pressing force applied by the pressing operation member 270 can be detected as a resistance value.

[0006] Figure 22 shows the state of change in resistance between the first and second wiring patterns 233 and 239 in response to the load applied to the pressure sensor 230. As shown in the figure, this pressure sensor 200 has the characteristic that the resistance value begins to decrease from the moment the pressing operation member 270 comes into contact with the upper surface of the pressure sensor 230, that is, immediately after the load is applied to the pressure sensor 200, and decreases rapidly as the load increases. In other words, it is a suitable configuration for use when it is desired to immediately detect that the pressure sensor 200 has been pressed. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2023-098376 [Overview of the project] [Problems that the invention aims to solve]

[0008] On the other hand, some devices using this type of pressure sensor require characteristics such as the resistance value not changing when only a small load is applied to the pressure sensor, and only beginning to change when a load exceeding a predetermined level is applied to the pressure sensor, or the resistance value decreasing more slowly than conventional sensors in response to the pressure applied to the pressure sensor. However, the pressure sensor 200 having the characteristics shown in Figure 22 above could not necessarily meet these requirements.

[0009] The present invention has been made in view of the above-mentioned points, and its purpose is to provide a pressure sensor that can obtain characteristics such as resistance not changing when pressed with a weak force, or resistance changing gradually in response to the pressing force. [Means for solving the problem]

[0010] The present invention relates to a pressure sensor whose resistance value changes in response to pressing force, comprising: a pressure detection substrate on which a pressure-sensitive sensor whose resistance value changes in response to pressing force is provided on a substrate; a spacer that is thicker than the thickness of the pressure-sensitive sensor and is installed on the pressure detection substrate at a position around the pressure-sensitive sensor; and a pressing member installed on the spacer and spanning across the pressure-sensitive sensor with a gap between them so as to be isolated from the pressure-sensitive sensor, wherein when a load is applied to the upper surface of the pressing member, the pressing member descends by the amount of the gap above the pressure-sensitive sensor and comes into contact with the pressure-sensitive sensor. According to the present invention, since there is a gap between the pressing member and the pressure sensor, if the upper surface of the pressing member is pressed lightly, the pressing member will not come into contact with the pressure sensor, and therefore the resistance value of the pressure sensor will not change. However, if the pressing member is pressed with a stronger force, the pressing member will come into contact with the pressure sensor and press it, causing a change in the resistance value, and making it possible to detect the pressing state. In other words, it is possible to obtain a characteristic in which the resistance value does not change with only a weak force.

[0011] In addition to the above features, the present invention is further characterized in that the spacer is provided with a pressure sensor exposure portion for exposing the pressure sensor, the pressing member is made of a flexible sheet placed on the spacer, and the portion of the pressing member located directly above the pressure sensor is a flexible portion that descends by the gap between the pressure sensor and the pressing member to contact and press the pressure sensor. According to the present invention, the flexible portion of the pressing member bends by the amount of the gap between the pressing member and the pressure sensor before contacting and pressing the pressure sensor. Therefore, the resistance value does not change initially, and the resistance value begins to change when pressed with a force exceeding a predetermined amount. Furthermore, if an even stronger force is applied, an additional pressing force is required to bend the flexible portion, so the resistance value changes relatively slowly in response to the pressing force. In other words, it is possible to obtain characteristics in which the resistance value does not change with only a weak force and characteristics in which the resistance value changes slowly in response to the pressing force.

[0012] In addition to the above features, the present invention is characterized in that multiple pressure sensors are provided at various locations on the substrate constituting the pressure detection substrate, and spacers thicker than the pressure sensors are installed between each pressure sensor. According to the present invention, the resistance value change characteristics can be obtained for each of the pressure sensors installed at multiple locations.

[0013] Furthermore, in addition to the above features, the present invention is characterized by having a cushioning member that is more flexible than the pressing member installed on the upper surface of the pressing member. According to the present invention, since the pressing member is pressed from above the cushioning member, the resistance value change characteristics can be further improved. That is, since the thickness of the cushioning member changes in accordance with the pressing force, the state in which the resistance value does not change at the beginning of pressing can be maintained for a longer pressing distance, and the state in which the resistance value changes, which begins at a pressing force above a predetermined level, can be made more gradual. Furthermore, by providing a cushioning element, the feel of pressing the pressure sensor can be made more flexible.

[0014] Furthermore, in addition to the above features, the present invention is characterized by having a hard pressing operation member installed on the upper part of the cushioning member to press the cushioning member from above. According to the present invention, since a flexible cushioning member is pressed by a hard pressing operating member, a soft pressing sensation can be provided, for example, when a hard pressing operating member is pressed by a person's finger. [Effects of the Invention]

[0015] According to the present invention, it is possible to obtain a pressure sensor having a characteristic that the resistance value does not change when only weakly pressed, or a characteristic that the resistance value gradually changes according to the pressing force.

Brief Description of the Drawings

[0016] [Figure 1] It is a schematic cross-sectional view of the pressure sensor 1-1 according to the first embodiment. [Figure 2] It is an exploded schematic cross-sectional view of the pressure sensor 1-1 (excluding the pressing operation member 130). [Figure 3] It is a schematic plan view of the main part of the portion provided with the pressure-sensitive sensor 20 of the pressure detection substrate 50. [Figure 4] It is a plan view of the spacer 70. [Figure 5] It is a plan view of the pressure sensor 1-1. [Figure 6] It is an operation explanatory view of the pressure sensor 1-1. [Figure 7] It is an operation explanatory view of the pressure sensor 1-1. [Figure 8] It is a diagram showing the state of change in the resistance value between the first and second wiring patterns 21-1 and 21-2 with respect to the load applied to the pressure sensor 1-1. [Figure 9] It is a schematic cross-sectional view of the pressure sensor 1-2 according to the second embodiment. [Figure 10] It is an exploded schematic cross-sectional view of the pressure sensor 1-2 (excluding the pressing operation member 130-2). [Figure 11] It is an operation explanatory view of the pressure sensor 1-2. [Figure 12] It is a schematic plan view showing the pressure detection substrate 50-3 used for the pressure sensor 1-3 according to the third embodiment. [Figure 13] It is a plan view of the spacer 70-3. [Figure 14] It is a plan view of the pressure sensor 1-3. [Figure 15]This figure shows the change in resistance between the first and second wiring patterns 21-3-1 and 21-3-2 in response to the load applied to the pressure sensor 1-3. [Figure 16] This is a schematic plan view showing the pressure detection substrate 50-4 used in the pressure sensor 1-4 according to the fourth embodiment. [Figure 17] This is a plan view of spacer 70-4. [Figure 18] This is a plan view of pressure sensor 1-4. [Figure 19] This is a schematic cross-sectional view showing an example of a conventional pressure sensor 200. [Figure 20] This is a schematic cross-sectional view of the main part of the pressure detection substrate 250 (Schematic cross-sectional view XX in Figure 21). [Figure 21] This is a plan view of the main parts of the pressure detection substrate 250. [Figure 22] This figure shows the state of change in resistance between the first and second wiring patterns 233 and 239 in response to the load applied to the pressure sensor 200. [Figure 23] This is a cross-sectional view of the pressing operation member 130-3. [Figure 24] This is a cross-sectional view of the pressing operation member 130-4. [Modes for carrying out the invention]

[0017] Embodiments of the present invention will be described in detail below with reference to the drawings. [First Embodiment] Figure 1 is a schematic cross-sectional view of a pressure sensor 1-1 according to a first embodiment of the present invention, and Figure 2 is a schematic exploded cross-sectional view of the pressure sensor 1-1 (excluding the pressing operation member 130). As shown in these figures, the pressure sensor 1-1 is constructed by placing a sheet-shaped spacer 70, a sheet-shaped pressing member 90, and a sheet-shaped cushioning member 110 on the upper surface of a pressure detection substrate 50 which is made up of a pressure sensor 20 provided on a substrate 10, and further arranging a pressing operation member 130 above the cushioning member 110. In the following description, "up" refers to the direction from which the pressing member 90 is viewed from the pressure detection substrate 50, and "down" refers to the opposite direction, but this is not intended to limit the direction in which the pressure sensor 1-1 is used.

[0018] Figure 3 is a schematic plan view of the main part of the pressure detection substrate 50 where the pressure sensor 20 is provided. As shown in the figure, the pressure detection substrate 50 is constructed by forming the pressure sensor 20 on the substrate 10. The pressure sensor 20 has a pair of first and second wiring patterns 21-1 and 21-2, first contact patterns 25-1 and 25-7 on the wiring side connected to each wiring pattern 21-1 and 21-2 respectively, and five independent linear first contact patterns 25-2, 3, 4, 5, and 6 that are not connected to either of the first contact patterns 25-1 and 25-7 on the wiring side. A circular pressure-sensitive resistor (pressure-sensitive layer, pressure-sensitive pattern) 27 is formed on these first contact patterns 25-1 to 25-7, and a position is formed on the pressure-sensitive resistor 27 that connects the portion C1 facing the first contact pattern 25-1 and the portion C2 facing the first contact pattern 25-2, and the position is formed that connects the portion C1 facing the first contact pattern 25-1 and the portion C2 facing the first contact pattern 25-2 Linear second contact patterns 35-1,2,3,4,5,6 are formed at the positions connecting portion C3 and portion C4 facing the first contact pattern 25-3, the position connecting portion C5 facing the first contact pattern 25-3 and portion C6 facing the first contact pattern 25-4, the position connecting portion C7 facing the first contact pattern 25-4 and portion C8 facing the first contact pattern 25-5, the position connecting portion C9 facing the first contact pattern 25-5 and portion C10 facing the first contact pattern 25-6, and the position connecting portion C11 facing the first contact pattern 25-6 and portion C12 facing the first contact pattern 25-7.

[0019] As a result, in each section C1 to C12, the upper and lower first and second contact patterns face each other via the thin pressure-sensitive resistor 27, and are electrically connected to each other through a resistance equal to the thickness of the pressure-sensitive resistor 27. Because the pressure-sensitive resistor 27 is thin, only the sections C1 to C12 of the entire pressure-sensitive resistor 27 act as a resistor between the upper and lower first and second contact patterns. In other words, the parts of the pressure-sensitive resistor 27 that do not face each other are not conductive to each other. Therefore, the first contact pattern 25-1 and the first contact pattern 25-7 are electrically connected in series in each section C1 to C12 through a resistance equal to the thickness of the pressure-sensitive resistor 27.

[0020] Each of the first contact patterns 25-1 to 25-7 is linear and arranged in four parallel rows horizontally, while each of the second contact patterns 35-1 to 35-6 is linear and arranged in four parallel rows vertically. That is, each of the first contact patterns 25-1 to 25-7 and each of the second contact patterns 35-1 to 35-6 are oriented in orthogonal directions, and their width dimensions are all the same. Therefore, each of the above-mentioned parts C1 to C12 is rectangular, and their areas are the same. Furthermore, each of the first contact patterns 25-1 to 25-7 and each of the second contact patterns 35-1 to 35-6 are arranged so as a whole to be point-symmetric with respect to the center of the circle.

[0021] To manufacture the pressure detection substrate 50, a substrate 10 is first prepared. The substrate 10 is made of a flexible synthetic resin film, and in this example, polyethylene terephthalate (PET) film is used.

[0022] Next, the first and second wiring patterns 21-1 and 21-2, and the first contact patterns 25-1 to 25-7 are simultaneously formed on the substrate 10 by screen printing a conductive paste (silver paste in this example).

[0023] Next, a pressure-sensitive resistor 27 is formed on the substrate 10 by screen printing carbon paste so as to cover the entire upper surface of all the first contact patterns 25-1 to 25-7 and parts of the first and second wiring patterns 21-1 and 21-2. In this example, the pressure-sensitive resistor 27 is circular, but it may be of various other shapes. The carbon paste is made using a conductive paint that is a mixture of a synthetic resin that remains flexible even after curing, carbon powder, and a solvent.

[0024] Next, the pressure sensor 20 is completed by forming the second contact patterns 35-1 to 35-6 on the upper surface of the pressure-sensitive resistor 27 by screen printing silver paste. It goes without saying that the above manufacturing procedure is just one example, and it may be manufactured using various other different procedures.

[0025] When a voltage is applied between the first and second wiring patterns 21-1 and 21-2, the pressure sensor 20 configured as described above will have the following characteristics: first wiring pattern 21-1 ⇒ first contact pattern 25-1 ⇒ pressure-sensitive resistor 27 of section C1 ⇒ second contact pattern 35-1 ⇒ pressure-sensitive resistor 27 of section C2 ⇒ first contact pattern 25-2 ⇒ pressure-sensitive resistor 27 of section C3 ⇒ second contact pattern 35-2 ⇒ pressure-sensitive resistor 27 of section C4 ⇒ first contact pattern 25-3 ⇒ pressure-sensitive resistor 27 of section C5 ⇒ second contact pattern 35-3 ⇒ Current flows through the following path: pressure-sensitive resistor 27 of section C6 ⇒ first contact pattern 25-4 ⇒ pressure-sensitive resistor 27 of section C7 ⇒ second contact pattern 35-4 ⇒ pressure-sensitive resistor 27 of section C8 ⇒ first contact pattern 25-5 ⇒ pressure-sensitive resistor 27 of section C9 ⇒ second contact pattern 35-5 ⇒ pressure-sensitive resistor 27 of section C10 ⇒ first contact pattern 25-6 ⇒ pressure-sensitive resistor 27 of section C11 ⇒ second contact pattern 35-6 ⇒ pressure-sensitive resistor 27 of section C12 ⇒ first contact pattern 25-7 ⇒ second wiring pattern 21-2.

[0026] In other words, the resistance between the first and second wiring patterns 21-1 and 21-2 is 12R[Ω], which is 12 times the resistance R[Ω] of the thickness of part C1 of the pressure-sensitive resistor 27, assuming that the resistance of each contact pattern is zero and that the areas of parts C1 to C12 are the same.

[0027] Figure 4 is a plan view of the spacer 70. As shown in the figure, the spacer 70 is made of a flexible synthetic resin sheet (for example, a PET sheet), and a pressure sensor exposure portion 71, which is a circular through hole, is provided in the portion facing the pressure sensor 20. The inner diameter of the pressure sensor exposure portion 71 is formed to be slightly larger than the outer diameter of the pressure-sensitive resistor 27. The thickness of the spacer 70 is also set to be thicker than the thickness of the pressure sensor 20.

[0028] The pressing member 90 shown in Figure 2 is made of a flexible synthetic resin sheet (for example, a PET sheet). The portion of this pressing member 90 located directly above the pressure sensor 20 (the portion facing the pressure sensor exposed portion 71 of the spacer 70) is designated as the flexible portion 91.

[0029] The cushioning member 110 shown in Figure 2 is a flexible sheet-like member, and is made of a material that is more flexible than the pressing member 90, such as felt. The thickness of the cushioning member 110 is greater than the thickness of the pressing member 90.

[0030] The pressing operation member 130 shown in Figure 1 is composed of a rod-shaped member made of a hard synthetic resin. Figure 5 is a plan view of the pressure sensor 1-1 shown in Figure 1, viewed from above. The pressing operation member 130 is cylindrical in shape, and its outer diameter is smaller than the inner diameter of the pressure sensor exposed portion 71 of the spacer 70.

[0031] To assemble the pressure sensor 1-1, the spacer 70 shown in Figure 4 is placed on the pressure detection substrate 50 shown in Figure 3, and the pressing member 90 and the cushioning member 110 shown in Figure 2 are placed on top of it. The pressure detection substrate 50, spacer 70, pressing member 90, and cushioning member 110 are all or any of them bonded together with an adhesive layer (not shown). Furthermore, as shown in Figure 1, the pressing operation member 130 is installed above the cushioning member 110 with a predetermined gap in between. At this time, as shown in Figure 5, the pressing operation member 130 is located in the center of the pressure sensor exposed portion 71 of the spacer 70 and directly above the pressure sensor 20.

[0032] As shown in Figure 1, the pressure sensor 1-1 assembled as described above has a spacer 70 thicker than the pressure sensor 20 interposed between the pressure detection substrate 50 and the pressing member 90. Therefore, a gap S1 is formed between the pressure sensor 20 and the pressing member 90 at the pressure sensor exposed portion 71 of the spacer 70. In other words, the pressing member 90 is stretched across the pressure sensor exposed portion 71 of the spacer 70 via the gap S1 so as to be isolated from the pressure sensor 20.

[0033] Next, the operation of the pressure sensor 1-1 will be explained. First, the pressing operation member 130, located in the position shown in Figure 1, is pressed down from above to bring it into contact with the upper surface of the buffer member 110, as shown in Figure 6. At this point, no load has yet been applied to the pressure sensor 1-1. Also, in this state, the pressing member 90 has not yet come into contact with the pressure sensor 20, so the output of the pressure sensor 20 remains at its original resistance value.

[0034] Next, by pressing the pressing operation member 130, the cushioning member 110 and the pressing member 90 are bent downwards. As shown in Figure 7, the portions of the pressing member 90 and the cushioning member 110 that face the pressure sensor exposed portion 71 of the spacer 70 (the bent portion 91 of the pressing member 90) bend downwards in the direction of the pressure and touch the surface of the pressure sensor 20. If the pressing operation member 130 is pressed further, the pressure sensor 20 begins to be pressed, and the resistance value of the pressure sensor 20 decreases in accordance with the increase in load due to the pressing.

[0035] When increasing the load on the pressure sensor 20 after it has started to press, it is necessary to further flex the flex portion 91 of the pressing member 90 and the cushioning member 110 above it. Therefore, the pressing force applied by the pressing operation member 130 must be increased to include the force required for this flexing.

[0036] Figure 8 shows the change in resistance between the first and second wiring patterns 21-1 and 21-2 in response to a load applied to the pressure sensor 1-1 (a load applied from the state shown in Figure 6, where the lower surface of the pressing operation member 130 is in contact with the upper surface of the buffer member 110). As shown in the figure, in this pressure sensor 1-1, even when a load is applied from the state shown in Figure 6, where the pressing operation member 130 is in contact with the upper surface of the buffer member 110, the resistance value does not change until a predetermined load value is reached (until the pressing member 90 contacts the pressure sensor 20). This range (indicated by the arrow) is referred to as the non-responsive region A.

[0037] As the load is increased after the pressing member 90 has made contact with the pressure sensor 20, the resistance value gradually decreases as the pressing member 90 presses against the pressure sensor 20. The rate of decrease in the resistance value at this point is gentler than the rate of decrease shown in Figure 22.

[0038] As explained above, since there is a gap S1 between the pressing member 90 and the pressure sensor 20, if the upper surface of the pressing member 90 is pressed only slightly, the pressing member 90 will not come into contact with the pressure sensor 20, and therefore the resistance value of the pressure sensor 20 will not change. However, if the pressing member 90 is pressed with a stronger force, the pressing member 90 will come into contact with the pressure sensor 20 and press it, causing a change in the resistance value and making it possible to detect the pressed state. In other words, it is possible to provide a pressure sensor 1-1 that has the characteristic that the resistance value does not change with only a weak force.

[0039] Furthermore, since the pressure sensor 1-1 has a buffer member 110 that is more flexible than the pressing member 90 installed on the upper surface of the pressing member 90, the pressing member 90 is pressed from above the buffer member 110, which further improves the resistance value change characteristics. Specifically, since the thickness of the buffer member 110 changes in accordance with the pressing force, the state in which the resistance value does not change at the beginning of pressing can be maintained for a longer pressing distance, and the decrease in the resistance value that starts at a pressing force above a predetermined level can be made more gradual. In addition, by providing the buffer member 110, the pressing operation feel of the pressure sensor 1-1 can be made more flexible.

[0040] Furthermore, in the above-mentioned pressure sensor 1-1, a hard pressing operation member 130 is installed on the upper part of the cushioning member 110 to press the cushioning member 110 from above. As a result, the flexible cushioning member 110 is pressed by the hard pressing operation member 130. Therefore, for example, when pressing the hard pressing operation member 130 with a person's finger, a soft pressing sensation can be provided, making it suitable when such a pressing sensation is desired. In the above example, the pressing operation member 130 is positioned opposite the cushioning member 110 with a predetermined gap in between, but the initial state may be the state shown in Figure 6, where the pressing operation member 130 is in contact with the cushioning member 110 without providing such a gap.

[0041] [Second Embodiment] Figure 9 is a schematic cross-sectional view of a pressure sensor 1-2 according to a second embodiment of the present invention, and Figure 10 is an exploded schematic cross-sectional view of the pressure sensor 1-2 (excluding the pressing operation member 130-2). In the pressure sensor 1-2 shown in these figures, the same or equivalent parts as those in the pressure sensor 1-1 shown in Figures 1 to 7 are denoted by the same reference numerals (however, each reference numeral is denoted by the subscript "-2"). Except for matters described below, the present invention is the same as that of the embodiment shown in Figures 1 to 7.

[0042] The only difference between pressure sensor 1-2 and pressure sensor 1-1 is that it does not have a buffer member 110. Therefore, the lower surface of the pressing operation member 130-2 is directly opposite the upper surface of the pressing member 90-2 at a predetermined distance apart.

[0043] In other words, the pressure sensor 1-2 is configured by placing a spacer 70-2, a pressing member 90-2, and a pressing operation member 130-2 on the upper surface of a pressure detection substrate 50-2, which is made up of a pressure-sensitive sensor 20-2 mounted on a substrate 10-2.

[0044] Then, by pressing down on the pressing operation member 130-2 located in the position shown in Figure 9, it is lowered and brought into contact with the upper surface of the pressing member 90-2. Further increasing the pressing force on the pressing operation member 130-2 causes the pressing member 90-2 to bend downward, as shown in Figure 11. This causes the flexible portion 91-2 of the pressing member 90-2 to bend, descend within the pressure sensor exposed portion 71-2 of the spacer 70-2, and touch the surface of the pressure sensor 20-2. Further pressing of the pressing operation member 130-2 causes the pressure sensor 20-2 to begin to be pressed, and the resistance value of the pressure sensor 20-2 decreases in accordance with the increase in load.

[0045] When the pressing member 90-2 descends by the gap S1-2, the resistance value of the pressure sensor 20-2 does not change. Furthermore, when the load is increased after the pressing member 90-2 contacts the upper surface of the pressure sensor 20-2, it is necessary to further bend the flexible portion 91-2 of the pressing member 90-2. As a result, the force pressing the pressing operation member 130-2 increases, including the force required for this bending, just as in the case of the pressure sensor 1-1. However, since the buffer member 110 is not installed as in the pressure sensor 1-1, if the pressure sensor 1-2 is constructed using the same material, shape, and dimensions as the pressure sensor 1-1, the non-responsive region A becomes shorter compared to the case of the pressure sensor 1-1. Also, the decrease in resistance value that begins when the pressure sensor 20-2 is pressed becomes steeper than in the case of the pressure sensor 1-1. In addition, by not providing the buffer member 110, the pressing operation feel of the pressure sensor 1-2 can be made firmer. Therefore, if you want to obtain such a change in resistance value and feel the operation, pressure sensor 1-2 is suitable.

[0046] [Third Embodiment] Figure 12 is a schematic plan view showing the pressure detection substrate 50-3 used in the pressure sensor 1-3 according to the third embodiment of the present invention, Figure 13 is a plan view of the spacer 70-3, Figure 14 is a plan view of the pressure sensor 1-3, and Figure 23 is a cross-sectional view of the pressing operation member 130-3 (viewed along the YY cross-sectional arrow in Figure 14). In these figures, the same or corresponding parts as those in the pressure sensor 1-1 according to the embodiments shown in Figures 1 to 7 are denoted by the same reference numerals (however, each reference numeral is denoted by the subscript "-3"). Except for matters described below, the present invention is the same as that of the embodiments shown in Figures 1 to 7.

[0047] The difference between pressure sensor 1-3 and pressure sensor 1-1 is that, as shown in Figure 12, four first contact patterns 25-3-1 to 25-3-4 and four first contact patterns 25-3-5 to 25-3-8 are separated and arranged in parallel in two locations, and pressure sensors 20-3a and 20-3b are provided in two spaced-apart locations in a separated state, and two second contact patterns 35-3-1, 35-3-2 and two second contact patterns 35-3-3 and 35-3-4 are arranged in parallel on these pressure sensors 20-3a and 20-3b, and the shape of spacer 70-3 and pressing operation member 130-3 have been changed accordingly. The pressing member 90-3 and cushioning member 110-3 installed on spacer 70-3 are both made of flat sheets, as in the case of pressure sensor 1-1.

[0048] The pressure detection substrate 50-3 is formed on substrate 10-3 simultaneously by screen printing conductive paste (silver paste in this example) onto the substrate 10-3, forming first and second wiring patterns 21-3-1 and 21-3-2, linear first contact patterns 25-3-1 to 25-3-8, and the contact connection patterns 26-3-1 to 26-3-3 described below. The four (or more) first contact patterns 25-3-1 to 25-3-4 are arranged in a straight line, and the other four (or more) first contact patterns 25-3-5 to 25-3-8 are arranged in a straight line parallel to the aforementioned row of first contact patterns 25-3-1 to 25-3-4. The first wiring pattern 21-3-1 is connected to the first contact pattern 25-3-1, and the first wiring pattern 21-3-2 is connected to and extends from the first contact pattern 25-3-8. Furthermore, the first contact pattern 25-3-2 and the first contact pattern 25-3-3 are connected by a contact connection pattern 26-3-1, the first contact pattern 25-3-4 and the first contact pattern 25-3-5 are connected by a contact connection pattern 26-3-2, and the first contact pattern 25-3-6 and the first contact pattern 25-3-7 are connected by a contact connection pattern 26-3-3.

[0049] Pressure-sensitive resistors 27-3, 27-3 are formed at two locations on the substrate 10-3 so as to cover the entire upper surface of the four first contact patterns 25-3-1 to 25-3-4 and the entire upper surface of the four first contact patterns 25-3-5 to 25-3-8, as well as a portion of the first and second wiring patterns 21-3-1 and 21-3-2 of the pressure-sensing substrate 50-3. The pressure-sensitive resistors 27-3, 27-3 are rectangular in shape and are arranged in parallel at a predetermined distance apart.

[0050] Then, linear second contact patterns 35-3-1 and 35-3-2 are formed on these two pressure-sensitive resistors 27-3, 27-3 at positions connecting the portion C1-3 facing the first contact pattern 25-3-1 and the portion C2-3 facing the first contact pattern 25-3-2, and at positions connecting the portion C3-3 facing the first contact pattern 25-3-3 and the portion C4-3 facing the first contact pattern 25-3-4, respectively. Additionally, linear second contact patterns 35-3-3 and 35-3-4 are formed at positions connecting the portion C5-3 facing the first contact pattern 25-3-5 and the portion C6-3 facing the first contact pattern 25-3-6, and at positions connecting the portion C7-3 facing the first contact pattern 25-3-7 and the portion C8-3 facing the first contact pattern 25-3-8, respectively. The above sections C1-3 to C8-3 are all rectangular in shape, and their areas are identical.

[0051] As described above, when a voltage is applied between the first and second wiring patterns 21-3-1 and 21-3-2 of the pressure sensor 20-3 (20-3a,b), the following occurs: First wiring pattern 21-3-1 ⇒ First contact pattern 25-3-1 ⇒ Pressure-sensitive resistor 27-3 of section C1-3 ⇒ Second contact pattern 35-3-1 ⇒ Pressure-sensitive resistor 27-3 of section C2-3 ⇒ First contact pattern 25-3-2 ⇒ First contact pattern 25-3-3 ⇒ Pressure-sensitive resistor 27-3 of section C3-3 ⇒ Second contact pattern 35-3-2 ⇒ Section C4 Current flows through the following path: -3 pressure-sensitive resistor 27-3 ⇒ first contact pattern 25-3-4 ⇒ first contact pattern 25-3-5 ⇒ part C5-3 pressure-sensitive resistor 27-3 ⇒ second contact pattern 35-3-3 ⇒ part C6-3 pressure-sensitive resistor 27-3 ⇒ first contact pattern 25-3-6 ⇒ first contact pattern 25-3-7 ⇒ part C7-3 pressure-sensitive resistor 27-3 ⇒ second contact pattern 35-3-4 ⇒ part C8-3 pressure-sensitive resistor 27-3 ⇒ first contact pattern 25-3-8 ⇒ second wiring pattern 21-3-2.

[0052] In other words, the resistance between the first and second wiring patterns 21-3-1 and 21-3-2 is 8R[Ω], which is 8 times the resistance R[Ω] of the thickness of part C1-3 of the pressure-sensitive resistor 27-3, assuming that the resistance of each contact pattern is zero and that the areas of parts C1-3 to C8-3 are the same.

[0053] Figure 13 is a plan view of spacer 70-3. As shown in the figure, spacer 70-3 is constructed with pressure sensor exposed portions 71-3, 71-3 on both sides of the central spacer 70-3 (spacer portion). Although not shown, spacer portions are also provided around the pressure sensor exposed portions 71-3, 71-3. Each pressure sensor exposed portion 71-3, 71-3 is formed in a shape that extends in the vertical direction of the paper in Figure 13, so as to expose the entire pressure-sensitive resistors 27-3, 27-3 and also include the entire portion facing the lower end surfaces 131-3, 131-3 of the pressing operation member 130-3 described below. Furthermore, the thickness of spacer 70-3 is configured to be greater than the thickness of the pressure sensor 20-3 (20-3a, b).

[0054] As shown in Figure 14, the pressure sensor 1-3 is constructed by placing a spacer 70-3, a pressing member 90-3, and a cushioning member 110-3 on a pressure detection substrate 50-3, and positioning a pressing operation member 130-3 above them.

[0055] As shown in Figure 23, the pressing operation member 130-3 is made of a rigid synthetic resin molded product with a U-shaped cross-section. As shown in the same figure, the pressing operation member 130-3 is made up of an upper wall 137-3 and left and right side walls 135-3, 135-3, with the lower surfaces of the side walls 135-3, 135-3 serving as the lower end surfaces 131-3, 131-3. As shown in Figure 14, the left and right linear lower end surfaces 131-3, 131-3 of the pressing operation member 130-3 are positioned above the pair of pressure sensors 20-3a, 20-3b shown in Figure 12, and more specifically, directly above the pairs of linearly arranged second contact patterns 35-3-1, 35-3-2 and second contact patterns 35-3-3, 35-3-4.

[0056] In this pressure sensor 1-3 as well, a spacer 70-3 thicker than the pressure sensors 20-3a and 20-3b is interposed between the pressure detection substrate 50-3 and the pressing member 90-3. As a result, a gap is formed between the pressure sensors 20-3a and 20-3b and the pressing member 90-3 at the pressure sensor exposed portions 71-3 and 71-3 of the spacer 70-3. In other words, the pressing member 90-3 is spanned across the pressure sensor exposed portions 71-3 and 71-3 of the spacer 70-3 via the gap, so as to isolate it from the pressure sensors 20-3a and 20-3b.

[0057] Then, when the pressing operating member 130-3 is pressed down from above, the lower end surfaces 131-3, 131-3 of the pressing operating member 130-3 come into contact with the upper surface of the cushioning member 110-3. Next, by further increasing the pressing force on the pressing operating member 130-3 and bending the cushioning member 110-3 and the pressing member 90-3 downwards, the portions of the pressing member 90-3 and the cushioning member 110-3 facing the pressure sensor exposed portions 71-3, 71-3 of the spacer 70-3 are pushed in the direction of the pressure and move downwards, causing the moved pressing member 90-3 to touch the surfaces of the pressure sensors 20-3a, 20-3b. Furthermore, when the pressing operation member 130-3 is pressed, the pressure sensors 20-3a and 20-3b begin to be pressed by the pressing member 90-3, and the resistance values ​​of the pressure sensors 20-3a and 20-3b decrease in accordance with the increase in load.

[0058] Figure 15 shows the change in resistance values ​​between the first and second wiring patterns 21-3-1 and 21-3-2 in response to a load applied to the pressure sensor 1-3 (a load applied after the lower end surfaces 131-3, 131-3 of the pressing operation member 130-3 are in contact with the upper surface of the buffer member 110). As shown in the figure, in this pressure sensor 1-3, even when a load is applied after the lower end surfaces 131-3, 131-3 of the pressing operation member 130-3 are in contact with the upper surface of the buffer member 110-3, the resistance value does not change until a predetermined load value is reached (until the pressing member 90-3 contacts the pressure sensors 20-3a, 20-3b). This range (indicated by the arrow) is referred to as the non-responsive region A-3.

[0059] As the pressing load applied by the pressing operation member 130-3 is increased after the pressing member 90-3 has come into contact with the pressure sensors 20-3a and 20-3b, the resistance value gradually decreases as the pressing member 90-3 presses against the pressure sensors 20-3a and 20-3b. However, the rate of decrease in the resistance value at this time is slower than in the case shown in Figure 22.

[0060] As described above, in this pressure sensor 1-3, there is a gap between the pressing member 90-3 and the pressure sensors 20-3a and 20-3b. Therefore, if the upper surface of the pressing member 90-3 is pressed lightly by the pressing operation member 130-3, the pressing member 90-3 does not come into contact with the pressure sensors 20-3a and 20-3b, and thus the resistance values ​​of the pressure sensors 20-3a and 20-3b do not change. However, if the pressing operation member 130-3 is pressed with a stronger force, the pressing member 90-3 will come into contact with and press the pressure sensors 20-3a and 20-3b, causing a change in resistance values ​​and making it possible to detect the pressed state.

[0061] In this embodiment as well, the buffer member 110-3 can be omitted, as in the second embodiment. In this embodiment, the first contact pattern 25-3-1 to the last first contact pattern 25-3-8 are connected in series, but the four first contact patterns 25-3-1 to 25-3-4 on one side may be connected in series, and the first contact patterns 25-5 to 25-3-8 on the other side may be connected in series, and each may be configured as a separate output circuit. In other words, the circuit configuration of each first contact pattern 25-3-1 to 25-3-8 can be various different circuit configurations. If the first contact patterns 25-3-1 to 25-3-4 and the first contact patterns 25-3-5 to 25-3-8 are each configured as separate output circuits, the resistance change characteristics can be obtained separately for each of the multiple pressure sensors 20-3a and 20-3b.

[0062] Furthermore, if, as in the pressure sensor 1-3, two sets (or more sets) of pressure sensors 20-3a and 20-3b are provided, and a spacer 70-3 thicker than these pressure sensors 20-3a and 20-3b is installed between each pressure sensor 20-3a and 20-3b, it becomes possible to provide pressure sensors that correspond to various shapes and structures of pressing operation members, such as the pressing operation member 130-3 having multiple parallel lower end surfaces 131-3, 131-3.

[0063] [Fourth Embodiment] Figure 16 is a schematic plan view showing the pressure detection substrate 50-4 used in the pressure sensor 1-4 according to the fourth embodiment of the present invention, Figure 17 is a plan view of the spacer 70-4, Figure 18 is a plan view of the pressure sensor 1-4, and Figure 24 is a cross-sectional view of the pressing operation member 130-4 (viewed along the ZZ cross-sectional arrow in Figure 18). In these figures, the same or corresponding parts as those in the pressure sensor 1-1 according to the embodiments shown in Figures 1 to 7 are denoted by the same reference numerals (however, each reference numeral is denoted by the subscript "-4"). Except for matters described below, the present invention is the same as that of the embodiments shown in Figures 1 to 7.

[0064] The difference between pressure sensor 1-4 and pressure sensor 1-1 is that, as shown in Figure 16, the five first contact patterns 25-4-1 to 25-4-5 are arranged in a U-shape overall, and the pressure sensor 20-4 is provided in a roughly U-shape accordingly. The shape of the pressure sensor exposed portion 71-4 of the spacer 70-4 and the shape of the pressing operation member 130-4 have been changed accordingly. The pressing member 90-4 and the cushioning member 110-4 installed on the spacer 70-4 are both made of flat sheets, similar to the case of pressure sensor 1-1.

[0065] The pressure detection substrate 50-4 has first and second wiring patterns 21-4-1, 21-4-2 and linear first contact patterns 25-4-1 to 25-4-5 formed on the substrate 10-4 by screen printing conductive paste (silver paste in this example). The two first contact patterns 25-4-1, 25-4-5 connected to the first and second wiring patterns 21-4-1, 21-4-2 are spaced apart to the left and right, while the three independent first contact patterns 25-4-2 to 25-4-4 are arranged in a straight line adjacent to the two first contact patterns 25-4-1, 25-4-5, so that the first contact patterns 25-4-1 to 25-4-5 as a whole are arranged in a U-shape.

[0066] A pressure-sensitive resistor 27-4 is formed in a U-shape on the substrate 10-4 so as to cover the entire upper surface of the five first contact patterns 25-4-1 to 25-4-5 of the pressure detection substrate 50-4, and a portion of the first and second wiring patterns 21-4-1 and 21-4-2.

[0067] Then, a linear second contact pattern 35-4-1 is formed on the pressure-sensitive resistor 27-4 at a position connecting the portion C1-4 facing the first contact pattern 25-4-1 and the portion C2-4 facing the first contact pattern 25-4-2, a second contact pattern 35-4-2 is formed on the portion C3-4 facing the first contact pattern 25-4-2, and a second contact pattern 35-4-1 is formed on the portion C4-4 facing the first contact pattern 25-4-3 A second contact pattern 35-4-4 is formed in portion C5-4 opposite to the first contact pattern 25-4-3, a second contact pattern 35-4-5 is formed in portion C6-4 opposite to the first contact pattern 25-4-4, and a second contact pattern 35-4-6 is formed at a position connecting portion C7-4 opposite to the first contact pattern 25-4-4 and portion C8-4 opposite to the first contact pattern 25-4-5. Furthermore, the second contact pattern 35-4-2 and the second contact pattern 35-4-3 are connected by a contact connection pattern 36-4-1, and the second contact pattern 35-4-4 and the second contact pattern 35-4-5 are connected by a contact connection pattern 36-4-2. In addition, portions C1-4 to C8-4 are all rectangular in shape, and their areas are the same.

[0068] When a voltage is applied between the first and second wiring patterns 21-4-1 and 21-4-2 of the pressure sensor 20-4 configured as described above, the following occurs: First wiring pattern 21-4-1 ⇒ First contact pattern 25-4-1 ⇒ Pressure-sensitive resistor 27-4 of section C1-4 ⇒ Second contact pattern 35-4-1 ⇒ Pressure-sensitive resistor 27-4 of section C2-4 ⇒ First contact pattern 25-4-2 ⇒ Pressure-sensitive resistor 27-4 of section C3-4 ⇒ Second contact pattern 35-4-2 ⇒ Second contact pattern 35-4-3 ⇒ Current flows through the following path: pressure-sensitive resistor 27-4 in section C4-4 ⇒ first contact pattern 25-4-3 ⇒ pressure-sensitive resistor 27-4 in section C5-4 ⇒ second contact pattern 35-4-4 ⇒ second contact pattern 35-4-5 ⇒ pressure-sensitive resistor 27-4 in section C6-4 ⇒ first contact pattern 25-4-4 ⇒ pressure-sensitive resistor 27-4 in section C7-4 ⇒ second contact pattern 35-4-6 ⇒ pressure-sensitive resistor 27-4 in section C8-4 ⇒ first contact pattern 25-4-5 ⇒ second wiring pattern 21-4-2.

[0069] In other words, the resistance between the first and second wiring patterns 21-4-1 and 21-4-2 is 8R[Ω], which is 8 times the resistance R[Ω] of the thickness of part C1-4 of the pressure-sensitive resistor 27-4, assuming that the resistance of each contact pattern is zero and that the areas of parts C1-4 to C8-4 are the same.

[0070] Figure 17 is a plan view of the spacer 70-4. As shown in the figure, the spacer 70-4 has a U-shaped pressure sensor exposure portion 71-4. The pressure sensor exposure portion 71-4 is formed to be slightly larger than the outer dimensions of the pressure-sensitive resistor 27-4 so as to expose the entire pressure-sensitive resistor 27-4. The thickness of the spacer 70-4 is also set to be greater than the thickness of the pressure-sensitive sensor 20-4.

[0071] As shown in Figure 18, the pressure sensor 1-4 is constructed by placing a spacer 70-4, a pressing member 90-4, and a cushioning member 110-4 on a pressure detection substrate 50-4 and bonding them together, with a pressing operation member 130-4 positioned above them.

[0072] As shown in Figure 24, the pressing operation member 130-4 is made of a rigid synthetic resin molded product with a U-shaped cross-section. As shown in the same figure, the pressing operation member 130-4 is made up of an upper wall 137-4, left and right side walls 135-4, 135-4 and a tip wall 139-4. The lower surfaces of the side walls 135-4, 135-4 are designated as lower end surfaces 131-4, 131-4, and the lower surface of the tip wall 139-4 is designated as the tip-side lower end surface 133-4. The tip-side lower end surface 133-4 of the pressing operation member 130-4 is positioned directly above the sections C2-4 to C7-4, one of the lower end surfaces 131-4 is positioned directly above section C1-4, and the other lower end surface 131-4 is positioned directly above section C8-4. The pressing operation member 130-4 is capable of swinging up and down with its base (the lower side of the paper showing the pressing operation member 130-4 in Figure 18) as the pivot point. Therefore, the lower end surface 133-4 on the tip side swings up and down more than the base portion of the pressing operation member 130-4.

[0073] In this pressure sensor 1-4 as well, a spacer 70-4 thicker than the pressure sensor 20-4 is interposed between the pressure detection substrate 50-4 and the pressing member 90-4. As a result, a gap is formed between the pressure sensor 20-4 and the pressing member 90-4 at the pressure sensor exposed portion 71-4 of the spacer 70-4. In other words, the pressing member 90-4 is spanned across the pressure sensor exposed portion 71-4 of the spacer 70-4 via the gap, so as to be isolated from the pressure sensor 20-4.

[0074] Then, when the pressing operating member 130-4 is pressed down from above, the lower end surface 133-4 on the tip side and the left and right lower end surfaces 131-4, 131-4 of the pressing operating member 130-4 come into contact with the upper surface of the cushioning member 110-4. Next, when the pressing operating member 130-4 is pressed further, causing the cushioning member 110-4 and the pressing member 90-4 to bend downward, the portions of the pressing member 90-4 and the cushioning member 110-4 facing the pressure sensor exposed portion 71-4 of the spacer 70-4 are pushed in the direction of the pressure, bending and bending downward, and touching the surface of the pressure sensor 20-4. When the pressing operating member 130-4 is pressed further, the pressure sensor 20-4 begins to be pressed, and the resistance value of the pressure sensor 20-4 decreases in accordance with the increase in load.

[0075] As described above, since there is a gap between the pressing member 90-4 and the pressure sensor 20-4, if the upper surface of the pressing member 90-4 is pressed slightly and lowered, the pressing member 90-4 will not come into contact with the pressure sensor 20-4, and therefore the resistance value of the pressure sensor 20-4 will not change. However, if the pressing member 90-4 is pressed with a stronger force, the pressing member 90-4 will come into contact with the pressure sensor 20-4 and press it, causing a change in the resistance value and making it possible to detect the pressed state. In this embodiment as well, the buffer member 110-4 can be omitted as in the second embodiment.

[0076] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible within the scope of the claims, specification, and drawings. Furthermore, any shape, structure, or material not directly described in the specification and drawings is within the scope of the technical idea of ​​the present invention as long as it achieves the function and effect of the present invention. For example, the spacer may consist of multiple pieces, provided it is installed around the pressure sensor on the pressure detection substrate. The spacer may also be formed by coating (printing) a resin paste or the like to the upper surface of the pressure detection substrate or the lower surface of the pressing member with a desired thickness. The pressing member is also not limited to one piece, and may consist of multiple pieces as needed. The pressing member is not limited to a flexible sheet, but may be made of various other materials or structures, such as an elastic rubber-like material. The key is that it is installed on the spacer, spanned across the pressure sensor with a gap separating it, and when a load is applied to the upper surface of the pressing member, it descends by the gap above the pressure sensor and contacts the pressure sensor. Furthermore, it is not always necessary to install a pressing operation member; for example, the system may be configured so that the cushioning member or pressing member is directly pressed by a finger.

[0077] Furthermore, the embodiments described above and shown in the figures can be combined, provided that there is no contradiction in their purpose and structure. Also, even if only a part of the descriptions above and shown in the figures is included, each can constitute an independent embodiment, and the embodiments of the present invention are not limited to a single embodiment that combines the above descriptions and figures. [Explanation of symbols]

[0078] 1-1~1-4 Pressure Sensor 10 circuit boards 20 Pressure-sensitive sensors 50 Pressure detection board 70 Spacer 71 Exposed part of pressure sensor S1 Gap 90 Pressing member 91 Flexible section 110 Cushioning material 130 Pressing operation member

Claims

1. In a pressure sensor where the resistance value changes according to the pressing force, A pressure detection board is provided on the substrate with a pressure sensor whose resistance value changes according to the pressing force, A spacer having a thickness greater than the thickness of the pressure sensor and installed on the pressure detection substrate at a position near the pressure sensor, A pressing member is installed on the spacer and spanned across a gap so as to be isolated from the pressure sensor, It is equipped with, The pressure sensor is characterized in that when a load is applied to the upper surface of the pressing member, it descends by the amount of the gap on the pressure sensor and comes into contact with the pressure sensor.

2. A pressure sensor according to claim 1, The spacer is provided with a pressure sensor exposure portion that exposes the pressure sensor. The pressing member is made of a flexible sheet placed on the spacer, A pressure sensor characterized in that the portion of the pressing member located directly above the pressure sensor is a flexible portion that descends by the amount of the gap between the pressure sensor and the pressing member to contact and press the pressure sensor.

3. A pressure sensor according to claim 1 or 2, A pressure sensor characterized in that a plurality of pressure sensors are provided on a substrate constituting the pressure detection substrate, and a spacer thicker than the pressure sensor is installed between each pressure sensor.

4. A pressure sensor according to claim 1 or 2, A pressure sensor characterized in that a cushioning member, which is more flexible than the pressing member, is installed on the upper surface of the pressing member.

5. A pressure sensor according to claim 4, A pressure sensor characterized by having a rigid pressing operation member installed on the upper part of the cushioning member to press the cushioning member from above.

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