Capacitive sensor operation detection device

Abstract

This invention provides a "capacitive sensor operation detection device" that does not malfunction due to temperature rise caused by LED illumination. [Solution] When the capacitance value RAW of the capacitance sensor 1 does not exceed the value obtained by adding the operation occurrence prediction threshold Th2 to the baseline BL, the baseline BL is updated to follow RAW. If RAW exceeds the value obtained by adding Th2 to the baseline BL, the baseline BL is fixed to its current value. When RAW becomes greater than the fixed baseline BL by Th1 (Th1 > Th2), a user operation is detected, and in response, the LED 5 is lit. If the LED 5 is lit, the baseline BL is increased by the increase in capacitance A of the capacitance sensor 1 due to the temperature rise caused by the lighting of the LED 5 (a).

Description

Technical Field

[0001] The present invention relates to a technique for detecting an operation on a capacitance sensor.

Background Art

[0002] As a technique for detecting an operation on a capacitance sensor, when the detected value RAW of the capacitance of the capacitance sensor is greater than or equal to Th1 than the baseline that is set, the operation is detected, and when it is not greater than or equal to Th1, the operation is not detected. During the period when the operation is not detected, the baseline is made to follow RAW, and during the period when the operation is detected, the baseline is fixed (for example, Patent Document 1).

[0003] Here, the operation on the capacitance sensor is a touch of the user's finger on the capacitance sensor, or an approach and touch of the user's finger on the capacitance sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When lighting near the capacitance sensor in response to the detection of an operation and maintaining the lighting during the detection of the operation, after the operation is detected, RAW increases regardless of the presence or absence of the operation due to a change in the dielectric constant of the capacitance sensor caused by a temperature rise due to the lighting. And in such a case, according to the above-described technique, since the baseline is fixed to the baseline before the lighting of the illumination during the detection of the operation, even after the user's operation is completed, RAW remains greater than or equal to Th1 than the baseline, and the user's operation continues to be detected and the lighting of the illumination may continue to be maintained.

[0006] Therefore, the present invention aims to correctly detect whether or not a user is performing an operation, even when the lighting near the capacitive sensor turns on in response to the detection of an operation. [Means for solving the problem]

[0007] To solve the aforementioned problems, the present invention provides an operation detection device for a capacitance sensor, comprising: a capacitance sensor; a lighting device disposed near the capacitance sensor; a RAW detection unit that detects the capacitance value of the capacitance sensor as RAW; a baseline setting unit that sets a baseline which is a reference value for the capacitance value used to detect user operations; a lighting control means that turns on the lighting device when the difference between the RAW detected by the RAW detection unit and the set baseline becomes greater than a first level while the lighting device is off; and an operation detection means that detects operations on the capacitance sensor based on the difference between the RAW detected by the RAW detection unit and the set baseline.

[0008] Here, the baseline setting unit updates the baseline to follow the RAW detected by the RAW detection unit when the difference between the RAW detected by the RAW detection unit and the set baseline is less than or equal to the second level, which is less than or equal to the first level. When the difference between the RAW detected by the RAW detection unit and the set baseline is not less than the second level, the baseline is fixed. When the lighting device is turned on, the baseline is changed by a predetermined amount in a direction that changes the capacitance of the capacitance sensor due to the temperature rise caused by the lighting device.

[0009] Furthermore, in order to solve the above problems, the present invention provides an operation detection device for a capacitance sensor, comprising: a capacitance sensor; a lighting device disposed near the capacitance sensor; a RAW detection unit that detects the capacitance value of the capacitance sensor as RAW; a baseline setting unit that sets a baseline which is a reference value of the capacitance value for detecting user operation; a lighting control means that turns on the lighting device when the RAW detected by the RAW detection unit is greater than the set baseline plus a first threshold Th1; and an operation detection means that detects an operation on the capacitance sensor when the RAW detected by the RAW detection unit is greater than the set baseline plus a first threshold Th1.

[0010] Here, the baseline setting unit updates the baseline to follow the RAW detected by the RAW detection unit when the RAW detected by the RAW detection unit is not greater than the set baseline plus a second threshold Th2 (|Th2|≦|TH1|), and fixes the baseline when the RAW detected by the RAW detection unit is greater than the set baseline plus a second threshold Th2, and changes the baseline by a predetermined amount in the direction in which the capacitance changes due to the temperature rise caused by the lighting of the lighting device when the lighting device is turned on.

[0011] Furthermore, in order to solve the above problems, the present invention provides an operation detection device for a capacitance sensor, comprising: a capacitance sensor; a lighting device disposed near the capacitance sensor; a RAW detection unit that detects the capacitance value of the capacitance sensor as RAW; a baseline setting unit that sets a baseline which is a reference value of the capacitance value for detecting user operation; a lighting control means that turns on the lighting device when the RAW detected by the RAW detection unit becomes smaller than a value obtained by subtracting a first threshold from the set baseline when the lighting device is turned off; and an operation detection means that detects an operation on the capacitance sensor when the RAW detected by the RAW detection unit is smaller than a value obtained by subtracting a first threshold Th from the set baseline.

[0012] Here, the baseline setting unit updates the baseline to follow the RAW detected by the RAW detection unit when the RAW detected by the RAW detection unit is not less than the value obtained by subtracting the second threshold Th2 (|Th2|≦|TH1|) from the set baseline, fixes the baseline when the RAW detected by the RAW detection unit is less than the value obtained by subtracting the second threshold Th2 from the set baseline, and changes the baseline by a predetermined amount in the direction in which the capacitance of the capacitance sensor changes due to the temperature rise caused by the lighting device being turned on.

[0013] Here, the relationship between Th1 and TH2 described above can be expressed as |Th2|<|TH1|. Furthermore, in the above-described capacitive sensor operation detection device, the predetermined amount may be an amount that is pre-set as the amount by which the capacitance of the capacitive sensor changes due to the temperature rise caused by the lighting device. Furthermore, the above-described capacitive sensor operation detection device may be configured such that the brightness of the lighting device is variable when it is turned on, the lighting control means changes the brightness of the lighting device when it is turned on according to the brightness of the ambient light, and the baseline setting unit changes the predetermined amount according to the brightness of the lighting device when it is turned on, which is set in advance.

[0014] Furthermore, the above-described capacitance sensor operation detection device may be configured such that, when the lighting device is turned off, the baseline setting unit changes the baseline by a predetermined amount in the opposite direction to the direction in which the capacitance of the capacitance sensor changes due to the temperature rise caused by the lighting device being on.

[0015] Furthermore, the above-described capacitance sensor operation detection device may be configured in the lighting control means to turn off the lighting device when it stops detecting an operation to the capacitance sensor while the lighting device is lit, or when a predetermined period of time has elapsed without detecting an operation to the capacitance sensor since it stopped detecting an operation to the capacitance sensor. Furthermore, in the above-described capacitive sensor operation detection device, the capacitive sensor and the lighting device may constitute a switch unit together with a plate-shaped member on which a predetermined pattern appears on the front surface only when the lighting device is turned on, and the capacitive sensor may be positioned on the back side of the plate-shaped member, near the plate-shaped member.

[0016] According to the capacitance sensor operation detection device described above, when the lighting device is turned on, the baseline used as the reference for operation detection is changed by the same amount as the change in capacitance of the capacitance sensor due to the temperature rise caused by the lighting device being turned on, and in the direction of that change. Therefore, the baseline can be maintained at an appropriate value even while the lighting device is on, and malfunctions caused by changes in the capacitance of the capacitance sensor due to the temperature rise caused by the lighting device can be suppressed. [Effects of the Invention]

[0017] As described above, according to the present invention, even when the lighting near the capacitive sensor turns on in response to the detection of an operation, it is possible to correctly detect whether or not a user has performed an operation. [Brief explanation of the drawing]

[0018] [Figure 1]It is a diagram showing the configuration of a data processing system according to an embodiment of the present invention. [Figure 2] It is a diagram showing the arrangement of a capacitance sensor and an LED according to an embodiment of the present invention. [Figure 3] It is a flowchart showing the baseline tracking process according to an embodiment of the present invention. [Figure 4] It is a flowchart showing the baseline temperature compensation process according to an embodiment of the present invention. [Figure 5] It is a diagram showing an example of an operation detection operation of a capacitance sensor according to an embodiment of the present invention. [Figure 6] It is a flowchart showing another example of the baseline temperature compensation process according to an embodiment of the present invention. [Figure 7] It is a diagram showing another example of the operation detection operation of a capacitance sensor according to an embodiment of the present invention. [Figure 8] It is a flowchart showing another example of the baseline tracking process according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described. FIG. 1 shows the configuration of the data processing system according to the present embodiment. As shown in the figure, the data processing system includes a capacitance sensor 1, a RAW detection unit 2, an operation detection unit 3, a baseline setting unit 4, an LED 5, an LED driving unit 6, a control unit 7, and a data processing device 8. Here, FIG. 2a shows the arrangement of the capacitance sensor 1 and the LED 5. FIG. 2a is a diagram showing a switch unit composed of the capacitance sensor 1 and the LED 5, and the switch unit includes a decorative plate 91, a mask plate 92, the capacitance sensor 1, and the LED 5. The decorative plate 91 is a plate-like member having a decoration such as a grain pattern on the front surface as shown in FIG. 2b1, and the front surface is exposed to the space where the user is located. As shown in Figure 2b2, the mask plate 92 is a plate-shaped member that forms a mask that transmits light only to the icon pattern portion and blocks light from other parts, and is placed on the back side of the decorative plate 91. The capacitive sensor 1 is transparent and is positioned on the back side of the mask plate 92, and the LED 5 is positioned on the back side of the capacitive sensor 1. As shown in Figure 2a, the decorative panel 91 reflects some of the light incident on its front surface and transmits some of the light incident on its back surface. In addition, the space on the back side of the decorative panel 91 is closed and becomes a dark area when the LED 5 is not lit. Therefore, when LED5 is not lit, as shown in Figure 2c1, only the decoration on the front surface of the decorative panel 91 is visible to the user, and when LED5 is lit, as shown in Figure 2c2, icons are superimposed on the decoration on the front surface of the decorative panel 91 as seen to the user.

[0020] Returning to Figure 1, the capacitance sensor 1 is a self-capacitive sensor, and its capacitance value increases when the user's finger approaches. The RAW detection unit 2 repeatedly detects the capacitance value of the capacitance sensor 1 as a RAW value. The operation detection unit 3 detects whether or not the user has performed an operation on the switch unit. That is, the operation detection unit 3 is set with a baseline that serves as a criterion for detecting whether or not an operation has been performed. The operation detection unit 3 then determines the detection result to be operation detected when the RAW detected by the RAW detection unit 2 is greater than or equal to the operation detection threshold Th1 than the set baseline, and determines the detection result to be operation not detected when it is not greater than or equal to the baseline. Here, an operation on the switch unit by the user refers to approaching the capacitive sensor 1 with a finger or touching the icon display position on the decorative panel 91.

[0021] The baseline setting unit 4 sets the baseline described above for the operation detection unit 3. The process of setting up this baseline will be described in detail later. The control unit 7 has an operation acceptance mode and a standby mode. When in standby mode, if the operation detection unit 3 detects an operation, it instructs the LED drive unit 6 to light up LED 5, notifies the baseline setting unit 4 of the lighting up of LED 5, and transitions to operation acceptance mode. During the operation acceptance mode, the operation detection unit 3 notifies the data processing unit 8 of the detection result, and the data processing unit 8 performs predetermined processing according to the notified detection result. Furthermore, if the control unit 7 is in operation acceptance mode and a predetermined period of time has elapsed since the detection result of the operation detection unit 3 became "no operation detected" without the detection result of the operation detection unit 3 changing to "operation detected," the control unit 7 instructs the LED drive unit 6 to turn off the LED 5, notifies the baseline setting unit 4 that the LED 5 has been turned off, and transitions to standby mode.

[0022] The LED drive unit 6 turns on LED 5 when instructed to do so by the control unit 7, and turns off LED 5 when instructed to do so by the control unit 7. Therefore, when the user brings their finger close to the switch unit while the icon is not superimposed on the decorative panel 91 in Figure 2a, and only the decoration of the decorative panel 91 is visible to the user, the LED 5 lights up, the icon appears superimposed on the decorative panel 91, and when the user performs an operation on the icon display position, the data processing device 8 performs processing corresponding to that operation. Then, when the user finishes the operation and moves their finger away from the icon display position and a predetermined period of time has elapsed, the LED 5 turns off, the icon is no longer displayed on the decorative panel 91, and only the decoration of the decorative panel 91 is visible to the user.

[0023] Next, we will explain the operation of the baseline setting unit 4, which sets the baseline described above for the operation detection unit 3. After the data processing system is started, the baseline setting unit 4 performs baseline tracking processing and baseline temperature compensation processing in parallel. First, Figure 3 shows the operation of the baseline tracking process. In the following diagram, the baseline is represented by "BL". As shown in the figure, when the data processing system starts up, the baseline setting unit 4 first sets the baseline BL to the RAW detected by the RAW detection unit 2 (step 302). Then, the following process is repeated. In other words, the RAW detection unit 2 checks whether the detected RAW is less than the current baseline BL (step 304). If the RAW is less than the baseline BL, the baseline BL is updated to the RAW detected by the RAW detection unit 2 and set to the operation detection unit 3 (step 312).

[0024] If the RAW is not below the baseline BL (step 304), the system checks whether the value obtained by adding the operation occurrence prediction threshold Th2 to the current baseline BL is less than the RAW detected by the RAW detection unit 2 (step 306). If it is less than the RAW, the system predicts the occurrence of an operation and maintains the baseline BL at the current baseline BL (step 308).

[0025] Here, the operation occurrence prediction threshold Th2 is in a relationship Th1 ≥ Th2 with respect to the operation detection threshold Th1 used by the operation detection unit 3 to detect operation detection / non-detection. However, here, the operation occurrence prediction threshold Th2 is set to a value that satisfies Th1 > Th2, meaning that if the RAW detected by the RAW detection unit 2 is greater than the operation occurrence prediction threshold Th2 and greater than the current baseline BL, then the change in the RAW detected by the RAW detection unit 2 can be considered not to be a change not caused by user operation, such as a change in ambient temperature or aging.

[0026] On the other hand, if the value obtained by adding the operation occurrence prediction threshold Th2 to the baseline BL is not less than RAW, the baseline BL is updated so that the baseline BL approaches the RAW detected by the RAW detection unit 2, and set to the operation detection unit 3 (step 310). In step 310, the baseline BL may be updated to the RAW detected by the RAW detection unit 2, or the baseline BL may be updated by adding n% of the difference between the RAW and the baseline BL, or a predetermined value within a range where the baseline BL does not exceed the RAW. The baseline tracking process performed by the baseline setting unit 4 has been explained above. Next, Figure 4 shows the baseline temperature compensation process performed by the baseline setting unit 4. As shown in the figure, the baseline setting unit 4 performs baseline temperature compensation processing, If the state of LED5 changes from off to on (step 402), the baseline setting unit 4 repeatedly increases the capacitance change amount A when the light is turned on and sets it to the operation detection unit 3 (step 404). The determination of whether or not the state of LED5 has changed from off to on is made based on the notification from the control unit 7 that LED5 has been turned on.

[0027] Here, the capacitance change amount A when the light is turned on represents a pre-estimated value of the change in capacitance of the capacitance sensor 1 due to the temperature rise caused by the LED being turned on. Here, it is assumed that the capacitance of the capacitance sensor 1 increases with temperature rise. Furthermore, the capacitance change amount A when the light is turned on is set in the baseline setting unit 4 after the change in capacitance of the capacitance sensor 1 due to the temperature rise caused by the LED being turned on is determined in advance by experimentation or other means. Note that the capacitance change amount A when the light is turned on does not necessarily have to be the same as the change in capacitance of the capacitance sensor 1 due to the temperature rise caused by the LED being turned on; it is sufficient if it is a value approximately close to the change in capacitance of the capacitance sensor 1 due to the temperature rise caused by the LED being turned on.

[0028] Figure 5a shows an example of how such a data processing system detects user operations. To explain this detection operation along the time axis t, during periods when the user is not bringing their finger close to the switch unit, the RAW detected by the RAW detection unit 2 does not exceed the value obtained by adding the operation occurrence prediction threshold Th2 to the current baseline BL, so the baseline BL changes to follow the RAW.

[0029] Then, as the user's finger approaches the switch unit, if the RAW value exceeds the sum of the current baseline BL and the operation occurrence prediction threshold Th2, an operation is predicted, and the baseline BL is fixed to its current value. Then, as the finger moves closer and the RAW becomes greater than the fixed baseline BL, the operation detection unit 3 detects an operation, and in response, the control unit 7 lights up the LED 5 and notifies the baseline setting unit 4 that the LED 5 is lit. As a result, the temperature rise caused by the illumination of LED5 increases the capacitance of the capacitive sensor 1, causing RAW to increase by approximately A. Furthermore, the baseline setting unit 4, notified of the illumination of LED5, increases the baseline BL by A. Consequently, the baseline BL becomes approximately equal to the RAW value when the user's finger is off the switch unit during the period when LED5 is illuminated. From this point forward, using the increased baseline BL as the initial value, the baseline BL will be fixed to the value of the baseline BL at the time the value of RAW exceeds the current baseline BL plus the operation occurrence prediction threshold Th2, while the baseline BL will follow RAW during periods when the value does not exceed this threshold.

[0030] Furthermore, when the user brings their finger close to the icon display position and RAW becomes greater than the value obtained by adding the baseline BL to the operation detection threshold Th1, the detection result of the operation detection unit 3 becomes operation detected. When the user finishes the operation and moves their finger away from the decorative plate 91 and RAW is no longer greater than the value obtained by adding the baseline BL to the operation detection threshold Th1, the detection result of the operation detection unit 3 becomes operation not detected.

[0031] Then, after a predetermined period has elapsed since the operation detection unit 3 detected no operation when the user completes the operation on the switch unit and removes their finger, the LED 5 turns off and the RAW decreases by approximately A. At this time, the RAW does not exceed the value obtained by adding the operation occurrence prediction threshold Th2 to the current baseline BL, so the baseline BL follows the RAW and continues to follow the RAW until the RAW exceeds the operation occurrence prediction threshold Th2 on the current baseline BL.

[0032] Here, Figure 5b shows the detection operation of user operations when baseline temperature compensation processing is not performed, as a comparative example with this embodiment. As shown in the figure, the operation up to the LED lighting is the same as in Figure 5a, but when A > Th1, while the LED is lit, RAW remains greater than the value obtained by adding the operation occurrence prediction threshold Th2 to the baseline BL, so the baseline BL remains fixed to the baseline BL value at the time of operation occurrence prediction before the LED is lit. Therefore, when the user takes their finger off the switch unit after the LED 5 lights up, RAW, which has increased by A since before the LED was lit, remains greater than the value obtained by adding the operation detection threshold Th1 to the baseline BL, resulting in the detection value of the operation detection unit 3 remaining as operation detected, the detection value of the operation detection unit 3 not becoming operation not detected, and the LED 5 not turning off, resulting in a false detection of operation and a malfunction.

[0033] On the other hand, according to this embodiment, by performing the baseline temperature compensation process shown in Figure 4, the occurrence of such problems is suppressed, as shown in Figure 5a. Embodiments of the present invention have been described above. Furthermore, in the baseline temperature compensation process shown in Figure 4, if the control unit 7 notifies the operation detection unit 3 that the LED 5 has been turned off, the baseline setting unit 4 may reduce the capacitance change amount A when the lighting is on and set the baseline BL to a smaller value. By the way, the above describes the case where the capacitance of the capacitance sensor 1 increases due to a rise in temperature. However, this embodiment can also handle the case where the capacitance of the capacitance sensor 1 decreases due to a rise in temperature by changing the baseline temperature compensation process to the process shown in Figure 6.

[0034] In the baseline temperature compensation process shown in Figure 6, the baseline setting unit 4, when the state of LED 5 changes from off to on (step 602), reduces the baseline BL by the capacitance change amount A when the lighting is on and sets it to the operation detection unit 3 (step 604). When the state of LED 5 changes from on to off (step 606), it increases the baseline BL by the capacitance change amount A when the lighting is on and sets it to the operation detection unit 3 (step 608). This process is repeated. The determination of whether the state of LED 5 has changed from off to on, and whether the state of LED 5 has changed from on to off, is made based on the on / off notification of LED 5 from the control unit 7.

[0035] In this process, the capacitance change amount A when the lighting is turned on represents the absolute value of the prior estimated change in the capacitance of the capacitance sensor 1 due to the temperature rise caused by the LED lighting. Figure 7a shows an example of the detection operation of user operations when the capacitance of the capacitance sensor 1 decreases due to a rise in temperature. To explain this detection operation along the time axis t, during periods when the user is not bringing their finger close to the switch unit, the RAW detected by the RAW detection unit 2 does not exceed the value obtained by adding the operation occurrence prediction threshold Th2 to the current baseline BL, so the baseline BL changes to follow the RAW.

[0036] Then, as the user's finger approaches the switch unit, if the RAW value exceeds the sum of the current baseline BL and the operation occurrence prediction threshold Th2, an operation is predicted, and the baseline BL is fixed to its current value. Then, as the finger moves closer and the RAW value becomes greater than the sum of the fixed baseline BL and the operation detection threshold Th1, the operation detection unit 3 detects an operation, and in response, the control unit 7 lights up the LED 5 and notifies the baseline setting unit 4 that the LED 5 is lit. As a result, the temperature rise caused by the illumination of LED5 decreases the capacitance of the capacitance sensor 1, causing RAW to decrease by approximately A. Furthermore, the baseline setting unit 4, notified of the illumination of LED5, decreases the baseline BL by A. Consequently, the baseline BL becomes approximately equal to the RAW value when the user's finger is off the switch unit during the period when LED5 is illuminated. From this point forward, using the increased baseline BL as the initial value, the RAW value will be fixed at the baseline BL value at the time the baseline BL value was exceeded, while the baseline BL will follow the RAW value during periods when the baseline BL value is not exceeded.

[0037] Furthermore, when the user brings their finger close to the icon display position and RAW becomes greater than the value obtained by adding the operation detection threshold Th1 to the baseline BL, the detection result of the operation detection unit 3 becomes operation detected. When the user finishes the operation and moves their finger away from the decorative plate 91 and RAW is no longer greater than the value obtained by adding the operation detection threshold Th1 to the baseline BL, the detection result of the operation detection unit 3 becomes operation not detected.

[0038] Then, after a predetermined period has elapsed since the operation detection unit 3 detected no operation when the user completes the operation on the switch unit and removes their finger, LED 5 turns off, RAW increases by approximately A, and the baseline setting unit 4, notified of LED 5 turning off, increases baseline BL by A, making it approximately equal to RAW. The reason for increasing baseline BL by A when LED 5 turns off is to prevent baseline BL from becoming fixed when RAW increases by A, as RAW would become greater than the value of baseline B plus Th2.

[0039] Thereafter, until the RAW exceeds the operation occurrence prediction threshold Th2 with respect to the current baseline BL, the baseline BL continues to follow the RAW. Here, FIG. 7b shows the detection operation of the user's operation when the baseline temperature compensation process is not performed as a comparative example with the present embodiment. As shown in the figure, the operation until the LED lights up is the same as in FIG. 7a. However, when RAW - A < Th1 while the user's operation is occurring, the LED lights up. When the capacitance of the capacitance sensor 1 decreases due to the temperature rise for lighting the LED5, RAW < Th1, and an erroneous detection occurs where the detection value of the operation detection unit 3 becomes non - detection of operation even though the user's operation continues.

[0040] On the other hand, according to the present embodiment, by performing the baseline temperature compensation process shown in FIG. 6, as shown in FIG. 7a, the occurrence of such an erroneous detection is suppressed. Next, above, the case where the capacitance sensor 1 is a self - capacitance type in which the capacitance increases due to the approach of the user's finger has been shown. However, the present embodiment can also be applied by modifying as follows even when the capacitance sensor 1 is a mutual - capacitance type in which the capacitance decreases due to the approach of the user's finger.

[0041] That is, when the capacitance sensor 1 is a mutual - capacitance type, the operation detection unit 3 determines the detection result as operation detection when the RAW detected by the RAW detection unit 2 is smaller than the value obtained by subtracting the operation detection threshold Th1 from the set baseline, and determines the detection result as non - detection of operation when it is not smaller. Also, when the capacitance sensor 1 is a mutual - capacitance type, the baseline setting unit 4 performs the baseline following process as shown in FIG. 8. As shown in the figure, in this baseline following process, when the data processing system is activated, the baseline setting unit 4 first sets the baseline BL to the RAW detected by the RAW detection unit 2 (step 802). Thereafter, the following process is repeatedly performed. In other words, the RAW detection unit 2 checks whether the detected RAW exceeds the current baseline BL (step 804), and if the RAW exceeds the baseline BL, it updates the baseline BL to the RAW detected by the RAW detection unit 2 and sets it to the operation detection unit 3 (step 812).

[0042] If the RAW does not exceed the baseline BL (step 804), the system checks whether the value obtained by subtracting the operation occurrence prediction threshold Th2 from the current baseline BL exceeds the RAW detected by the RAW detection unit 2 (step 806). If it does not exceed the RAW, the system predicts the occurrence of an operation and maintains the baseline BL at the current baseline BL (step 808).

[0043] Here, the operation occurrence prediction threshold Th2 is defined as a value such that, if the RAW detected by the RAW detection unit 2 is greater than the operation occurrence prediction threshold Th2 and smaller than the current baseline BL, then the change in the RAW detected by the RAW detection unit 2 can be considered not to be a change not caused by user operation, such as a change in ambient temperature or aging. On the other hand, if the value obtained by subtracting the operation occurrence prediction threshold Th2 from the baseline BL exceeds the RAW value, the baseline BL is updated so that it approaches the RAW value detected by the RAW detection unit 2, and this is set in the operation detection unit 3 (step 810). In step 810, the baseline BL may be updated to the RAW detected by the RAW detection unit 2, or the baseline BL may be updated by subtracting a predetermined value from the difference between the RAW and the baseline BL by n%, or within a range where the baseline BL does not become less than the RAW. Next, in the above embodiment, the brightness of the LED 5 may be changed according to the brightness of the ambient light, and the capacitance change amount A when the lighting is on may also be changed according to the brightness of the LED 5. That is, in this case, an illuminance sensor for detecting the brightness of ambient light is provided near the switch unit. In the control unit 7, when the LED 5 is lit, the brightness of the LED 5 corresponding to the brightness of the ambient light detected by the illuminance sensor is instructed to the LED driving unit 6, and when notifying the baseline setting unit 4 of the lighting of the LED 5, the brightness of the LED 5 instructed to the LED driving unit 6 is also notified. Then, the LED driving unit 6 drives the LED 5 to have the brightness according to the instruction.

[0044] For example, the brightness of the LED 5 corresponding to the brightness of the ambient light detected by the illuminance sensor is classified into three levels of brightness of the ambient light, bright, dim, and dark, for example. When the ambient light is bright, the brightness of the LED 5 is set to be strong, when the ambient light is dim, the LED 5 is set to medium, and when the ambient light is dark, the LED 5 is set to weak.

[0045] Also, the baseline setting unit 4 registers candidate values Ai in association with each level of the brightness of the LED 5 controlled by the control unit 7. The candidate value Ai represents the candidate value associated with the brightness of the LED 5 at the i-th level. Also, the candidate value Ai is the change amount of the capacitance of the capacitance sensor 1 due to the temperature rise when the LED 5 is lit at the brightness of the i-th level obtained in advance.

[0046] Then, in the baseline setting unit 4, in step 402 of the baseline temperature compensation process in FIG. 4, steps 604 and 606 of the baseline temperature compensation process in FIG. 6, the candidate value Ai associated with the brightness of the LED 5 notified from the brightness control unit 7 of the LED 5 is used as the capacitance change amount A during lighting of the illumination to update the baseline.

[0047] Next, in the above embodiment, the operation detection unit 3 may further detect an approach operation at Th3 (Th3 < Th1), and the control unit 7 may switch between the operation reception mode and the standby mode and turn on / off the LED 5 according to the approach operation. In other words, in this case, if the detection result of the operation detection unit 3 is an approach operation detection while in standby mode, the LED drive unit 6 is instructed to light up LED 5, the illumination of LED 5 is notified to the baseline setting unit 4, and the system transitions to operation acceptance mode. Then, once the system transitions to operation acceptance mode, it notifies the data processing device 8 of the operation detection unit 3's detection results for operation detection / non-detection. Furthermore, when in operation acceptance mode, if the detection result of the operation detection unit 3 becomes "no approach operation detected" and a predetermined period of time has elapsed without the detection result of the operation detection unit 3 changing to "approach operation detected" or "operation detected," the control unit 7 instructs the LED drive unit 6 to turn off the LED 5, notifies the baseline setting unit 4 of the LED 5 being turned off, and transitions to standby mode.

[0048] By doing this, when the user's finger comes close enough to the switch unit, the LED 5 lights up to display an icon, and the system can then respond to the user's input by touching the icon display position on the decorative panel 91 or by approaching it further.

[0049] Next, in the above embodiment, if an icon is to be displayed as a response to a user operation, the following may be done. In other words, the control unit 7 operates in operation acceptance mode at all times, and when the LED 5 is off, if the operation detection unit 3 detects an operation, it notifies the data processing unit 8 of the operation detection, instructs the LED drive unit 6 to light up the LED 5, and then notifies the baseline setting unit 4 of the LED 5 being lit. Furthermore, when the LED 5 is lit, if the operation detection unit 3 detects no operation, the control unit 7 notifies the data processing unit 8 of the no-operation detection, instructs the LED drive unit 6 to turn off the LED 5, and notifies the baseline setting unit 4 that the LED 5 has been turned off. [Explanation of Symbols]

[0050] 1...Capacitive sensor, 2...RAW detection unit, 3...Operation detection unit, 4...Baseline setting unit, 5...LED, 6...LED drive unit, 7...Control unit, 8...Data processing unit, 91...Decorative panel, 92...Mask panel.

Claims

1. Capacitive sensor and, A lighting device positioned near the aforementioned capacitance sensor, A RAW detection unit that detects the capacitance value of the aforementioned capacitance sensor as RAW, A baseline setting unit sets a baseline that serves as a reference value for the capacitance value used to detect user operations, When the lighting device is turned off, a lighting control means turns on the lighting device when the difference between the RAW detected by the RAW detection unit and the set baseline becomes greater than a first level. The system includes an operation detection means for detecting an operation on the capacitance sensor based on the difference between the RAW detected by the RAW detection unit and a set baseline, The baseline setting unit, When the difference between the RAW detected by the RAW detection unit and the set baseline is smaller than the second level, which is a level lower than or equal to the first level, the baseline is updated to follow the RAW detected by the RAW detection unit. When the difference between the RAW detected by the RAW detection unit and the set baseline is not less than the second level, the baseline is fixed. A capacitance sensor operation detection device characterized by changing the baseline by a predetermined amount in a direction that changes the capacitance of the capacitance sensor due to the temperature rise caused by the lighting device when the lighting device is turned on.

2. Capacitive sensor and, A lighting device positioned near the aforementioned capacitance sensor, A RAW detection unit that detects the capacitance value of the aforementioned capacitance sensor as RAW, A baseline setting unit sets a baseline that serves as a reference value for the capacitance value used to detect user operations, When the lighting device is turned off, a lighting control means turns on the lighting device when the RAW detected by the RAW detection unit becomes greater than the value obtained by adding a first threshold Th1 to the set baseline, The system includes an operation detection means that detects an operation on the capacitance sensor when the RAW detected by the RAW detection unit is greater than a value obtained by adding a first threshold Th1 to a set baseline, The baseline setting unit, When the RAW detected by the RAW detection unit is not greater than the value obtained by adding a second threshold Th2 (|Th2|≦|TH1|) to the set baseline, the baseline is updated to follow the RAW detected by the RAW detection unit. When the RAW detected by the RAW detection unit is greater than the value obtained by adding a second threshold Th2 to the set baseline, the baseline is fixed. An operation detection device for a capacitance sensor, characterized in that when the lighting device is turned on, the baseline is changed by a predetermined amount in a direction that changes the capacitance due to the temperature rise caused by the lighting device being turned on.

3. Capacitive sensor and, A lighting device positioned near the aforementioned capacitance sensor, A RAW detection unit that detects the capacitance value of the aforementioned capacitance sensor as RAW, A baseline setting unit sets a baseline that serves as a reference value for the capacitance value used to detect user operations, When the aforementioned lighting device is turned off, a lighting control means turns on the lighting device when the RAW detected by the RAW detection unit becomes smaller than the value obtained by subtracting a first threshold Th1 from a set baseline. The system includes an operation detection means that detects an operation on the capacitance sensor when the RAW detected by the RAW detection unit is smaller than the value obtained by subtracting a first threshold Th11 from a set baseline, The baseline setting unit, When the RAW detected by the RAW detection unit is not less than the value obtained by subtracting the second threshold Th2 (|Th2|≦|TH1|) from the set baseline, the baseline is updated to follow the RAW detected by the RAW detection unit. When the RAW detected by the RAW detection unit is less than the value obtained by subtracting the second threshold Th2 from the set baseline, the baseline is fixed. A capacitance sensor operation detection device characterized by changing the baseline by a predetermined amount in a direction that changes the capacitance of the capacitance sensor due to the temperature rise caused by the lighting device when the lighting device is turned on.

4. An operation detection device for a capacitance sensor according to claim 2 or 3, A capacitive sensor operation detection device characterized by |Th2| < |TH1|.

5. An operation detection device for a capacitance sensor according to claim 1, 2, or 3, The capacitance sensor operation detection device is characterized in that the predetermined amount is a predetermined amount that is set as the amount by which the capacitance of the capacitance sensor changes due to the temperature rise caused by the lighting of the lighting device.

6. An operation detection device for a capacitance sensor according to claim 1, 2, or 3, The aforementioned lighting device has a variable brightness when lit. The lighting control means changes the brightness of the lighting device when it is turned on according to the brightness of the ambient light. The baseline setting unit is characterized by changing the predetermined amount according to the brightness of the lighting device when it is turned on, as set in advance, and is an operation detection device for a capacitance sensor.

7. An operation detection device for a capacitance sensor according to claim 1, 2, or 3, Capacitance sensor operation detection device, characterized in that the baseline setting unit changes the baseline by a predetermined amount in the opposite direction to the direction in which the capacitance of the capacitance sensor changes due to the temperature rise caused by the lighting of the lighting device when the lighting device is turned off.

8. An operation detection device for a capacitance sensor according to claim 1, 2, or 3, Capacitive sensor operation detection device, characterized in that the lighting control means turns off the lighting device when it stops detecting an operation to the capacitance sensor while the lighting device is lit, or when a predetermined period of time has elapsed without detecting an operation to the capacitance sensor since it stopped detecting an operation.

9. An operation detection device for a capacitance sensor according to claim 1, 2, or 3, The capacitance sensor and the lighting device constitute a switch unit together with a plate-shaped member on which a predetermined pattern appears only when the lighting device is turned on, and the capacitance sensor is positioned on the back side of the plate-shaped member, near the plate-shaped member, characterized in that it is located near the plate-shaped member.

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