Input device
The input device addresses the lack of push detection and click feeling in existing devices by using an elastic portion with specific stress-strain characteristics to provide tactile feedback, enabling consistent operation recognition.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ALPS ALPINE CO LTD
- Filing Date
- 2025-11-10
- Publication Date
- 2026-05-21
AI Technical Summary
Existing input devices using electrostatic sensors between a light source and a flexible layer fail to detect pushing operations on the flexible layer and cannot provide a click feeling without additional components like a return spring.
An input device with an elastic portion that is pushed by a detection object, a sensor portion to detect distance, and a determination portion to determine the presence of a pushing operation based on the detected distance, utilizing an elastic portion with specific stress-strain characteristics to provide a click feeling.
The input device effectively presents a click feeling to the operator without additional components, ensuring consistent recognition of pushing operations through tactile feedback.
Smart Images
Figure JP2025039265_21052026_PF_FP_ABST
Abstract
Description
Input device
[0001] The present invention relates to an input device.
[0002] Patent Document 1 below discloses a technique of providing a sensor such as an electrostatic sensor between a light source and a flexible layer in a light display member having light transmissibility and flexibility.
[0003] International Publication No. WO 2022 / 210932
[0004] However, since the technique of Patent Document 1 detects that a detection object has approached the sensor, it cannot detect a pushing operation on the flexible layer by the detection object. Further, the technique of Patent Document 1 cannot present a click feeling with respect to the pushing operation on the flexible layer by the detection object, and in order to present such a click feeling, it is necessary to separately provide a member such as a return spring.
[0005] An input device according to an embodiment includes an elastic portion that is pushed by a detection object, a sensor portion that detects the distance from the detection object with the elastic portion interposed therebetween, and a determination portion that determines the presence or absence of a pushing operation by the detection object based on the distance from the detection object detected by the sensor portion. The elastic portion has a characteristic of first taking a maximum value and then taking a minimum value when being pressed by the detection object in an evaluation curve obtained by differentiating with respect to strain a compression stress-strain curve having a compression stress as the vertical axis and strain as the horizontal axis when being pressed by the detection object.
[0006] According to an input device according to an embodiment, it is possible to present a click feeling to the operator of the pushing operation by the characteristic of the elastic portion without separately providing a member for generating the click feeling.
[0007] Figure 1 shows a schematic diagram illustrating the configuration of an input device according to one embodiment. Figure 2 shows the compression stress-strain curve of the elastic part of the input device according to one embodiment. Figure 3 shows the evaluation curve of the elastic part of the input device according to one embodiment. Figure 4 shows an example of the planar shape of the detection electrode of the input device according to one embodiment. Figure 5 shows an example of the output characteristics of the detection electrode of the input device according to one embodiment. Figure 6 shows the compression stress of the elastic part and the output characteristics of the detection electrode of the input device according to one embodiment. Figure 7 shows a schematic diagram illustrating the configuration of an input device according to a first modified example of the embodiment of one embodiment. Figure 8 shows a schematic diagram illustrating the configuration of an input device according to a second modified example of the embodiment of one embodiment. Figure 9 shows the compression stress-strain curve and evaluation curve of the elastic part of the input device according to a second modified example of the embodiment of one embodiment. Figure 1 shows a schematic diagram illustrating the configuration of an input device according to a third modified example of the embodiment of one embodiment.
[0008] An embodiment will be described below with reference to the drawings.
[0009] (Configuration of Input Device 100) Figure 1 is a schematic diagram showing the configuration of an input device 100 according to one embodiment. As shown in Figure 1, the input device 100 comprises a housing 110, a substrate 120, a plurality of detection electrodes 130, an elastic part 140, an electrostatic IC (Integrated Circuit) 150, and a determination unit 160.
[0010] The housing 110 is a box-shaped component made of a rigid resin material and has a hollow structure. In Figure 1, only a portion of the housing 110, where multiple detection electrodes 130 are provided, is shown.
[0011] The substrate 120 is located inside the housing 110 and is a horizontal, flat plate-shaped component made of a rigid resin material.
[0012] Multiple detection electrodes 130 are arranged side by side on the surface 110A of the housing 110. Each of the multiple detection electrodes 130 is a thin plate-shaped member made of a conductive material. The multiple detection electrodes 130 are provided corresponding to multiple indentation regions 140A in the elastic portion 140. In the example shown in Figure 1, each of the three detection electrodes 130 is provided below each of the three indentation regions 140A of the elastic portion 140.
[0013] Each of the multiple detection electrodes 130 is an example of a "sensor unit," and detects the distance to the object to be detected 10 (for example, the operator's finger) with the elastic part 140 in between. Note that there may be only one detection electrode 130. Therefore, it can be said that the "sensor unit" has one or more detection electrodes 130. Specifically, each of the multiple detection electrodes 130 is driven by a drive current supplied from the electrostatic IC 150. Each of the multiple detection electrodes 130 can detect the distance to the object to be detected 10 by changing its capacitance according to the proximity state of the object to be detected 10.
[0014] Here, the closer each of the multiple detection electrodes 130 is to the object to be detected 10, the greater the capacitive coupling with the object to be detected 10, and therefore the greater the capacitance. Consequently, each of the multiple detection electrodes 130 outputs a larger capacitance detection value to the electrostatic IC as it approaches the object to be detected 10. In other words, each of the multiple detection electrodes 130 detects the distance to the object to be detected 10 based on the capacitance value between it and the object to be detected 10.
[0015] The elastic part 140 is a component made of an elastic material that covers the surface 110A of the housing 110 and the plurality of detection electrodes 130. When the elastic part 140 is pressed by the object to be detected 10, the portion that is pressed undergoes elastic deformation into a concave shape. For example, the elastic part 140 can be made of foam, resin sheet, gel sheet, etc. Multiple pressable areas 140A are arranged side by side on the surface of the elastic part 140. Each of the pressable areas 140A functions as a push button.
[0016] The electrostatic IC 150 is mounted on the substrate 120. The electrostatic IC 150 is electrically connected to each of the multiple detection electrodes 130. The electrostatic IC 150 drives each of the multiple detection electrodes 130 by supplying a drive current to each of them. The electrostatic IC 150 also detects the capacitance of each of the multiple detection electrodes 130.
[0017] The determination unit 160 is connected to the electrostatic IC 150. Based on the capacitance of each of the multiple detection electrodes 130 detected by the electrostatic IC 150 (i.e., the distance to the object to be detected 10), the determination unit 160 determines whether or not a pressing operation has been performed by the object to be detected 10, and outputs the determination result to the outside. For example, when the capacitance of any one of the multiple detection electrodes 130 exceeds a predetermined threshold, the determination unit 160 determines that a pressing operation has been performed by the object to be detected 10 on the pressing area 140A in the elastic part 140 corresponding to that detection electrode 130. The determination unit 160's functions are realized by a processor executing a program stored in memory. The determination unit 160 is implemented, for example, by an IC.
[0018] (Characteristics of the elastic part 140) Figure 2 shows the compressive stress-strain curve of the elastic part 140 of the input device 100 according to one embodiment. Figure 3 shows the evaluation curve of the elastic part 140 of the input device 100 according to one embodiment.
[0019] The graph in Figure 2 shows a compressive stress-strain curve with compressive stress on the vertical axis and strain on the horizontal axis when the elastic part 140 is pressed by the object to be detected 10. The graph in Figure 3 shows an evaluation curve obtained by differentiating the compressive stress-strain curve shown in Figure 2 with respect to strain. Here, compressive stress is the stress when the elastic part 140 is pressed by a cylindrical object to be detected 10 with a diameter of 10 mm.
[0020] The strain of the elastic part 140 represents the percentage of deformation from the original thickness of the elastic part 140, and can be calculated using the following formula (1).
[0021]
[0022] Furthermore, the evaluation curve of the elastic part 140 can be obtained by the following formula (2).
[0023]
[0024] As shown in Figure 3, when the elastic part 140 is pressed by the object to be detected 10, the evaluation curve first takes a maximum value (270 kPa) at timing T1 when the strain is approximately 0.06, and then takes a minimum value (37 kPa) at timing T2 when the strain is approximately 0.41.
[0025] Therefore, when the operator performs a pressing operation on the elastic part 140, the rate of increase in the operating load changes abruptly when the timing T1, which is when the strain reaches approximately 0.06, is exceeded. The operator performing the pressing operation can perceive this abrupt change in the rate of increase of the operating load as a clicking sensation.
[0026] Therefore, in one embodiment of the input device 100, by selecting and using an elastic part 140 having the characteristics described above during the design stage, a click sensation can be presented to the operator performing the pressing operation through the characteristics of the elastic part 140, without the need to separately provide a member for generating a click sensation.
[0027] Here, it is preferable that the elastic part 140 has the characteristic that the ratio of the maximum value to the minimum value in the evaluation curve is 1.2 or more. This allows the input device 100 according to one embodiment to provide the operator with a stronger click feeling during the pressing operation. This configuration and effect were derived from experiments conducted by the inventors. In the example shown in Figure 3, the elastic part 140 has the characteristic that the ratio of the maximum value to the minimum value in the evaluation curve is 270 / 37 = 7.29, that is, 1.2 or more.
[0028] Furthermore, it is preferable that the elastic portion 140 has a 50% compressive strength of 500 kPa or less. This allows the input device 100 according to one embodiment to provide the operator with a click sensation with an appropriate operating force. This configuration and effect were derived from experiments conducted by the inventors.
[0029] (Example of Planar Shape and Output Characteristics of Detection Electrode 130) Figure 4 shows an example of the planar shape of the detection electrode 130 provided in the input device 100 according to one embodiment. Figure 5 shows an example of the output characteristics of the detection electrode 130 provided in the input device 100 according to one embodiment.
[0030] Figure 4 shows a top-down plan view of an input device 100 according to one embodiment. Note that in Figure 4, the elastic part 140 is not shown, so only the surface 110A of the housing 110 and the elliptical detection electrode 130 provided in the center of the surface 110A of the housing 110 are shown.
[0031] The capacitance value of the detection electrode 130 is affected not only by the distance from the object to be detected 10, but also by the area of the detection electrode 130. For this reason, if the minimum size of the object to be detected 10 is predetermined, it is preferable to make the size of the detection electrode 130 less than or equal to the minimum size of the object to be detected 10.
[0032] For example, in the example shown in Figure 4, the size of the object to be detected 10 (the operator's finger) (here, the finger diameter) is defined as 8 mm to 16 mm. For this reason, the planar shape of the detection electrode 130 is elliptical, and furthermore, the diameter of the detection electrode 130 is set to 8 mm, which is the same size as the minimum size of the object to be detected 10.
[0033] As a result, the detection electrode 130 is less affected by the size of the object to be detected 10 in terms of its capacitance value.
[0034] The graph in Figure 5 shows the relationship between the distance between the detection electrode 130 and the object to be detected 10 and the output of the detection electrode 130 when using the detection electrode 130 shown in Figure 4. In the graph in Figure 5, the solid line represents the case where the detection object 10 (operator's finger) with a size of 8 mm is pressed, and the dotted line represents the case where the detection object 10 (operator's finger) with a size of 16 mm is pressed. In other words, the case with a finger diameter of 8 mm assumes the operator is small in stature, and the case with a finger diameter of 16 mm assumes the operator is large in stature.
[0035] As shown in Figure 5, the output (capacitance value) of the detection electrode 130 increases as the distance to the object to be detected 10 decreases. Therefore, the detection electrode 130 can detect the distance to the object to be detected 10 based on the capacitance with the object to be detected 10.
[0036] Here, as shown in Figure 5, when the size of the object to be detected 10 is 16 mm, the output (capacitance value) of the detection electrode 130 remains almost unchanged, even though the area of the object to be detected 10 is approximately four times larger than when the size of the object to be detected 10 is 8 mm. This is because, as shown in Figure 4, the diameter of the detection electrode 130 is set to 8 mm, which is the same size as the minimum size of the object to be detected 10, thereby suppressing the influence of the size of the object to be detected 10 on the capacitance value of the detection electrode 130.
[0037] (Determination timing by the determination unit 160) Figure 6 shows the compressive stress of the elastic part 140 and the output characteristics of the detection electrode 130, which are provided in the input device 100 according to one embodiment.
[0038] The graph in Figure 6 shows the compressive stress of the elastic part 140 and the output characteristics of the detection electrode 130 when the elastic part 140 is pressed by the object to be detected 10. In the graph in Figure 6, the vertical axis represents the compressive stress of the elastic part 140, and the horizontal axis represents the count of the output of the electrostatic IC 150.
[0039] Furthermore, the graph in Figure 6 shows the compressive stress and output characteristics of the detection electrode 130 for two elastic parts 140 with different finger diameters. In the graph in Figure 6, the solid line shows the compressive stress of the elastic part 140 and the output characteristics of the detection electrode 130 when the finger diameter is Φ8 mm, and the dotted line shows the compressive stress of the elastic part 140 and the output characteristics of the detection electrode 130 when the finger diameter is Φ16 mm.
[0040] Furthermore, timings T1 and T1' in the graph shown in Figure 6 correspond to timing T1 in the graph shown in Figure 3 (i.e., the timing at which the evaluation curve reaches its maximum value).
[0041] As shown in Figure 6, in the input device 100 according to one embodiment, when the object to be detected 10 is pressed against the elastic part 140, the rate of increase in the compressive stress of the elastic part 140 changes rapidly at timing T1 or timing T1', so that the operator can feel a click. Note that the horizontal axis in Figure 6 is the capacitance value, so it is normally affected by area in addition to distance. However, as explained in Figures 4 and 5, the effect of area can be suppressed by setting the size (diameter) of the detection electrode 130 to be less than or equal to the minimum size of the object to be detected 10. Here, each of the one or more detection electrodes 130 has a diameter of 8 mm or less. That is, in Figure 6, regardless of whether the size of the object to be detected 10 is 8 mm (assuming a small person) or 16 mm (assuming a large person), the output of the electrostatic IC 150 changes monotonically in proportion to the distance.
[0042] The determination unit 160 determines that a pressing operation was performed by the object to be detected 10 at or after timing T1 and timing T1' (i.e., after the maximum value was exceeded in the evaluation curve). For example, the determination unit 160 determines that a pressing operation was performed by the object to be detected 10 when the capacitance of the multiple detection electrodes 130 becomes greater than or equal to a predetermined threshold corresponding to the distance between the object to be detected 10 and the detection electrodes 130 at the time the pressing operation was performed. Ideally, in order to determine whether or not it is after the timing when the maximum value was taken in the evaluation curve as shown in Figure 3, strain (distance between the object to be detected 10 and the detection electrodes 130) should be used as the threshold. However, as described above, by setting the size (diameter) of the detection electrodes 130 to be less than or equal to the minimum size of the object to be detected 10, the effect of area can be suppressed, and since the output of the electrostatic IC 150 changes monotonically in proportion to the distance, the determination unit 160 can use the output of the electrostatic IC 150 as the threshold.
[0043] As a result, the input device 100 according to one embodiment can determine that the pushing operation by the detection object 10 has been performed after the operator feels a click sensation at timing T1 or timing T1'. Therefore, the operator can tactilely grasp that the pushing operation performed on the elastic portion 140 has been detected by the determination unit 160 based on the click sensation generated in the elastic portion 140. In other words, since the input device 100 can determine that the pushing operation by the detection object 10 has been performed in accordance with the timing when the operator feels the click sensation, the recognition of pushing by both the operator and the input device 100 can be made consistent.
[0044] (First Modified Example) FIG. 7 is a schematic diagram showing the configuration of an input device 100-2 according to a first modified example of one embodiment. The input device 100-2 shown in FIG. 7 is different from the input device 100 shown in FIG. 1 in the points described below.
[0045] As shown in FIG. 7, the input device 100-2 further includes a skin 170 that covers the surfaces of the housing 110 and the elastic portion 140. A plurality of pushing regions 171, which are regions where a pushing operation is performed by the operator, are provided on the skin 170.
[0046] Further, the input device 100-2 includes an LED (Light Emitting Diode) 190, which is an example of a "light source", on the substrate 120. Further, in the input device 100-2, a sensor sheet 130A made of a transparent material (ITO (Indium Tin Oxide), PEDOT, etc.) extends from the electrostatic IC 150 and is provided on the surface 110A of the housing 110. A plurality of detection electrodes 130 for each pushing region 171 are provided on the sensor sheet 130A, so that each detection electrode 130 has translucency. Further, in the input device 100-2, the elastic portion 140 and the pushing region 171 of the skin 170 have translucency. Further, the input device 100-2 further includes a diffusion plate 180 provided so as to overlap the back surface of the detection electrode 130.
[0047] As a result, the input device 100-2 lights up the LED 190, diffuses the light emitted from the LED 190 by the diffusion plate 180, and further transmits it through the detection electrode 130, the elastic portion 140, and the pressing region 171 of the skin 170, so that the pressing region 171 provided on the skin 170 emits light and can be visually recognized by the operator.
[0048] Particularly, in the example shown in FIG. 7, since the LED 190 is provided for each of the plurality of pressing regions 171 in the input device 100-2, the plurality of pressing regions 171 can be individually made to emit light by individually lighting up the plurality of LEDs 190.
[0049] Here, by providing a mark for clarifying the pressing region 171, functions, etc. at the pressing region 171 of the skin 170 or at the position of the elastic portion 140 where the elastic portion 140 overlaps, when the LED 190 is lit, the mark can be made to emit light and be visually recognized by the operator.
[0050] Further, the skin 170 may have a pattern for decorating the surfaces of the housing 110 and the elastic portion 140. Also, the skin 170 may have a configuration in which the pressing region 171 is difficult to be visually recognized by the operator because the pressing region 171 is not illuminated when the LED 190 is not lit.
[0051] Also, when the input device 100-2 detects that the detection object 10 has approached a predetermined distance to any one of the plurality of pressing regions 171 by the one detection electrode 130 corresponding to the one pressing region 171, the LED 190 corresponding to the one pressing region 171 may be lit to cause the one pressing region 171 to emit light.
[0052] (Second Modified Example) FIG. 8 is a schematic diagram showing the configuration of an input device 100-3 according to a second modified example of an embodiment. The input device 100-3 shown in FIG. 8 is different from the input device 100 shown in FIG. 1 in the points described below.
[0053] As shown in Figure 8, the input device 100-3 has an elastic section 140 with a two-layer structure in which a first elastic member 141 and a second elastic member 142 are superimposed. The first elastic member 141 and the second elastic member 142 have different hardnesses.
[0054] Thus, the input device 100-3 according to the second modified example has a configuration in which two elastic members 141 and 142 with different hardnesses are superimposed on each other, so that the characteristics of the elastic part 140 (compressive stress-strain characteristics and evaluation curve) of the elastic part 140 become the target characteristics (see Figure 9).
[0055] In the example shown in Figure 8, the elastic portion 140 has a configuration in which two elastic members 141 and 142 with different hardnesses are stacked on top of each other. However, it is not limited to this configuration, and for example, the elastic portion 140 may have a configuration in which three or more elastic members with different hardnesses are stacked on top of each other.
[0056] Figure 9 shows the compressive stress-strain curve and evaluation curve of the elastic part 140 provided in the input device 100-3 according to a second modified example of one embodiment.
[0057] The graph in Figure 9 shows a compressive stress-strain curve (solid line in the figure) with compressive stress on the vertical axis and strain on the horizontal axis when the elastic part 140 of the input device 100-3 is pressed by the object to be detected 10, and an evaluation curve (dotted line in the figure) obtained by differentiating the compressive stress-strain curve with respect to strain.
[0058] As shown in Figure 9, the elastic part 140 of the input device 100-3 has the characteristic that when pressed by the object to be detected 10, the evaluation curve first takes a maximum value (454 kPa) at timing T1 when the strain is approximately 0.62, and then takes a minimum value (284 kPa) at timing T2 when the strain is approximately 0.73.
[0059] Thus, the elastic portion 140 of the input device 100-3 has a configuration in which two elastic members 141 and 142 with different hardnesses are superimposed, thereby changing the characteristics of the elastic portion 140 of the input device 100 as shown in Figures 2 and 3, and allowing the target characteristics shown in Figure 9 to be obtained.
[0060] In the example shown in Figure 9, the elastic portion 140 has a characteristic where the ratio of the maximum value to the minimum value in the evaluation curve is 454 / 284 = 1.60, that is, 1.2 or more.
[0061] (Third Modification) Figure 10 is a schematic diagram showing the configuration of an input device 100-4 according to a third modification of one embodiment. The input device 100-4 shown in Figure 10 differs from the input device 100 shown in Figure 1 in the respects that will be described below.
[0062] As shown in Figure 10, the input device 100-4 has an elastic section 140 with a two-layer structure in which a first elastic member 141 and a second elastic member 142 are superimposed in each of the multiple pressing regions 140A. The first elastic member 141 and the second elastic member 142 have different hardnesses. Furthermore, the multiple second elastic members 142 in the elastic section 140 can be made of materials with different hardnesses.
[0063] As a result, the input device 100-4 according to the third modified example can individually adjust the characteristics of each of the multiple indentation regions 140A so that the characteristics of each of the multiple indentation regions 140A (compression stress-strain characteristics and evaluation curve) become the target characteristics, by individually adjusting the stiffness of each of the multiple second elastic members 142 in the elastic portion 140.
[0064] In the example shown in Figure 10, each of the multiple indentation regions 140A in the elastic portion 140 has a configuration in which two elastic members 141 and 142 with different hardnesses are superimposed. However, the invention is not limited to this, and for example, each of the multiple indentation regions 140A in the elastic portion 140 may have a configuration in which three or more elastic members with different hardnesses are superimposed.
[0065] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to these embodiments, and various modifications or changes are possible within the scope of the gist of the present invention as described in the claims.
[0066] For example, in the above embodiment, a detection electrode 130 (capacitive sensor) was used as the sensor unit, but the invention is not limited to this, and other sensors capable of detecting the distance to the object to be detected 10 (for example, a pressure sensor, a vibration sensor, etc.) may be used as the sensor unit.
[0067] This international application claims priority based on Japanese Patent Application No. 2024-200841, filed on 18 November 2024, and the entire contents of said application are incorporated herein by reference.
[0068] 10. Objects to be detected: 100, 100-2, 100-3, 100-4. Input device: 110. Housing: 110A. Surface: 120. Substrate: 130. Detection electrode (sensor part): 130A. Sensor sheet: 140. Elastic part: 140A. Indentation area: 141. First elastic member: 142. Second elastic member: 150. Electrostatic IC: 160. Judgment unit: 170. Skin: 171. Indentation area: 180. Diffuser plate: 190. LED (light source):
Claims
1. An input device comprising: an elastic part that is pressed by an object to be detected; a sensor part that detects the distance between the elastic part and the object to be detected with the elastic part in between; and a determination part that determines whether or not an object to be detected has pressed based on the distance to the object to be detected detected by the sensor part, wherein the elastic part has the characteristic of taking a maximum value first and then a minimum value when pressed by the object to be detected, in an evaluation curve obtained by differentiating with respect to strain a compressive stress-strain curve, where the vertical axis is compressive stress and the horizontal axis is strain, when pressed by the object to be detected.
2. The input device according to claim 1, characterized in that the determination unit determines that the pressing operation was performed after the maximum value was exceeded in the evaluation curve when the elastic part was pressed by the object to be detected.
3. The input device according to claim 1 or 2, characterized in that the elastic portion has the characteristic such that the ratio of the maximum value to the minimum value is 1.2 or more.
4. The input device according to claim 1 or 2, characterized in that the elastic portion has a 50% compressive strength of 500 kPa or less.
5. The input device according to claim 1 or 2, characterized in that the sensor unit detects the distance based on the capacitance value between it and the object to be detected.
6. The input device according to claim 1 or 2, characterized in that the elastic portion has a pressing area on which the pressing operation is performed, the sensor portion and the elastic portion are light-transmitting, and the device further comprises a light source that irradiates light onto the pressing area via the sensor portion and the elastic portion.
7. The input device according to claim 1 or 2, characterized in that the elastic portion has a laminated structure in which a plurality of elastic members with different hardnesses are stacked on top of each other.
8. The input device according to claim 1 or 2, characterized in that the elastic portion has a plurality of pressing regions on which the pressing operation is performed, and each of the plurality of pressing regions has a laminated structure in which a plurality of elastic members of different hardness are stacked on top of each other.
9. The input device according to claim 1 or 2, characterized in that the sensor unit has one or more detection electrodes, and each of the one or more detection electrodes has a diameter of 8 mm or less.