Electronic timepiece, hand position detection method, and program

Abstract

An electronic timepiece is provided with: a hand; a gear provided corresponding to the pin and having a hole; a detection unit that is provided corresponding to the gear, detects light passing through a hole of the gear when a voltage is applied, and outputs a current corresponding to the detected amount of light; and a control unit that acquires the current-based value output by the detection unit at a predetermined timing, and performs needle position detection on the needle on the basis of a determination result of whether or not the current-based value is equal to or greater than a predetermined threshold value. The predetermined timing is a timing before the value based on the current output by the detection unit becomes a value in a stable state.

Description

Technical Field

[0001] The present invention relates to an electronic timepiece, a hand position detection method, and a program. Background Art

[0002] Conventionally, technology for detecting the hand position of an analog clock is known, as disclosed in Japanese Patent Application Laid-Open No. 2006-284444, in which a light-receiving element such as a phototransistor detects light emitted by a light-emitting element such as an LED or natural light. Conventional hand position detection, for example, using a light-emitting element such as an LED, involves applying a voltage to the light-receiving element to cause it to emit light. The hand position detection threshold is determined when the output current from the light-receiving element is stable (during the stable period).

[0003] However, in this conventional method, in order to reliably output a current exceeding the threshold from the light-receiving element, the power required to generate light from the light-emitting element must be increased, resulting in increased power consumption. Furthermore, if the user wishes to use natural light for needle position detection without using a light-emitting element, it is conceivable that the ambient light may be insufficient, preventing the light-receiving element from outputting a current exceeding the threshold. Summary of the Invention

[0004] An electronic clock according to an embodiment of the present invention comprises: a needle; a gear, which is provided corresponding to the needle and has a hole; a detection unit, which is provided corresponding to the gear, detects light passing through the hole of the gear when a voltage is applied, and outputs a current corresponding to the amount of light detected; and a control unit, which obtains a current-based value output by the detection unit at a specified timing, and detects the needle position of the needle based on a judgment result of whether the current-based value is above a predetermined threshold value, and the specified timing is a timing before the current-based value output by the detection unit becomes a value in a stable state. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 This is a cross-sectional view schematically showing a main portion of a portion related to hand position detection in the timepiece according to the first embodiment.

[0006] Figure 2 This is a block diagram showing a control structure of a main part of the timepiece according to the embodiment.

[0007] Figures 3A to 3D It is a schematic cross-sectional view schematically showing the arrangement relationship between the light emitting section and the detection section according to the first embodiment.

[0008] Figure 4 1 is a timing chart showing conventional hand position detection using a light emitting unit.

[0009] Figure 5This is a timing chart showing hand position detection in the present embodiment when a light emitting unit is used.

[0010] Figure 6 This is a cross-sectional view of the main parts schematically showing the relationship between the train wheel mechanism and the detection unit when the hole for hand position detection is in a through state in the timepiece according to the second embodiment.

[0011] Figure 7 This is a cross-sectional view of the main parts schematically showing the relationship between the train wheel mechanism and the detection unit when the hole for hand position detection of the timepiece according to the second embodiment is in a non-penetrating state.

[0012] Figure 8 This is a timing chart showing hand position detection according to the present embodiment when natural light is used.

[0013] Figure 9 This is a timing chart showing hand position detection in a modified example of the present embodiment when a light emitting unit is used. DETAILED DESCRIPTION

[0014] Below, refer to Figures 1 to 9 The following describes embodiments of the electronic timepiece, hand position detection method, and program of the present invention. Hereinafter, the electronic timepiece will be referred to simply as a "timepiece." While various technically preferred limitations are imposed in the embodiments described below to implement the present invention, the scope of the present invention is not limited to the following embodiments and illustrated examples.

[0015] [First embodiment]

[0016] Reference Figures 1 to 5 A first embodiment of the clock 100, the hand position detection method, and the program will be described. Figure 1 and Figure 2 As shown, the electronic timepiece 100 of this embodiment includes hands 3, a gear 31 corresponding to the hands 3, a detection unit 5, and a control unit 20, and displays the time in an analog manner. In this embodiment, the hands 3 include a second hand 3s, a minute hand 3m, and an hour hand 3h. Furthermore, the timepiece 100 is not limited to a three-hand timepiece having three hands 3; for example, a two-hand timepiece having only a minute hand 3m and an hour hand 3h may also be used.

[0017] Each needle 3 is assembled to a pointer shaft 32 with a common axis center, and is driven by a drive mechanism 30 (at Figure 2The second hand drive mechanism 30s, minute hand drive mechanism 30m, and hour hand drive mechanism 30h rotate around the pointer shaft 32 to appropriately indicate the time. Each drive mechanism 30 includes a gear train mechanism composed of gears 31 and a motor (not shown) that drives the gear train mechanism. In addition, the motor can be set corresponding to each hand 3, or one motor can be set corresponding to multiple hands 3. Figure 1 When the main parts of the clock 100 are viewed from the side section shown in FIG. Figure 1 From the upper side (the center is the up-down direction, the axial direction of the pointer shaft 32), the dial 11, the solar panel 12, the date wheel press member 33, the multiple gears 31 constituting the gear train mechanism, the substrate (main substrate 13), etc. are provided in order.

[0018] The gears 31 are stacked in the thickness direction H, and holes 310 are formed in at least a portion of the gears 31 that pass through in the thickness direction H. The gears 31 are rotated by the drive mechanism 30, and the holes 310 formed in the plurality of gears 31 overlap with each other at a predetermined time according to the rotation of the gears 31. At this time, the holes 310 pass through each other in the thickness direction H of the timepiece 100, so that light (in Figure 1 The light L1 (hereinafter referred to as "light L1") passes through the through hole 310. In the present embodiment, the light L1 passing through the through hole 310 is light emitted by the light emitting unit 4 (emitted light L1) to be described later.

[0019] like Figure 1 As shown, above and below the positions where the holes 310 formed in the plurality of gears 31 overlap each other, the light emitting portion 4 (at Figure 2 The second hand is a luminous part 4s, the minute hand is a luminous part 4m, the hour hand is a luminous part 4h) and the detection part 5 (in Figure 2 The detection unit 5s for the second hand, the detection unit 5m for the minute hand, and the detection unit 5h for the hour hand are arranged in a manner opposite to each other. The position where the light-emitting unit 4 and the detection unit 5 are relative to each other via the through hole 310 is the detection position of the hand position in this embodiment. In addition, with regard to the configuration of the light-emitting unit 4 and the detection unit 5, the light-emitting unit 4 and the detection unit 5 provided corresponding to any one of the hands 3 (second hand 3s, minute hand 3m, hour hand 3h) are of the same configuration. Therefore, hereinafter, when referred to as the "light-emitting unit 4", it is set to be a light-emitting unit including the light-emitting unit 4s for the second hand, the light-emitting unit 4m for the minute hand, and the light-emitting unit 4h for the hour hand, and when referred to as the "detection unit 5", it is set to be a detection unit including the detection unit 5s for the second hand, the detection unit 5m for the minute hand, and the detection unit 5h for the hour hand.

[0020] The light emitting unit 4 is a light emitting element such as an LED (Light Emitting Diode), which is turned on by applying a predetermined voltage (input voltage) to emit light. Figure 1 In the example shown, the light emitting unit 4 is mounted on the auxiliary substrate 14 arranged on the back side (lower side in the thickness direction H) of the dial 11 and the solar panel 12 so that the light emitting side faces the detection unit 5. In addition, the detection unit 5 is composed of, for example, a phototransistor ( Figure 5 The detector 5 is composed of a light-receiving element (shown as "PTr" in the figure). The detector 5 is located below the gear train mechanism, which is composed of gears 31 and drives each needle 3. Specifically, the detector 5 is arranged on the main substrate 13 and is located opposite the light-emitting unit 4.

[0021] Moreover, in the present embodiment, the detection portion 5 has a main light-receiving surface 51 having high light-receiving sensitivity and a secondary light-receiving surface 52 having lower light-receiving sensitivity than the main light-receiving surface 51, above and below the thickness direction H, and an electrode (not shown) is provided on the same side as the main light-receiving surface 51. That is, the main light-receiving surface 51 is the first surface having high light-receiving sensitivity and having an electrode portion, and the secondary light-receiving surface 52 is the surface on the opposite side of the main light-receiving surface 51 as the first surface, and is the second surface having lower light-receiving sensitivity than the main light-receiving surface 51. In the present embodiment, the detection portion 5 is mounted on the substrate (main substrate 13) in such a manner that the surface on the electrode side as the first surface (the surface on the main light-receiving surface 51 side) is oriented opposite to the substrate (for example, the main substrate 13). An electrode portion 131 is formed on the substrate (main substrate 13), and in the mounted state, the electrode of the detection portion 5 is electrically connected to the electrode portion 131 of the substrate (main substrate 13). That is, there is no need to protect the electrode side of the detection unit 5 with resin, or to lead wires from the electrodes and perform wire bonding. Instead, the detection unit 5 is directly mounted on the substrate (main substrate 13) via SMT. As a result, the thickness of the detection unit 5 can be reduced, allowing it to be installed in a small space. In addition, since wire bonding is not required, costs can be reduced. In addition, as a result, the secondary light-receiving surface 52 of the detection unit 5 is opposite the light-emitting unit 4.

[0022] When a voltage (input voltage) is applied to the detection unit 5, it detects light L1 and outputs a current corresponding to the amount of light detected by the detection unit 5. The amount of light detected when the detection unit 5 receives only the light L1 emitted by the light emitting unit 4 is defined as the amount of light in the "stable state." In the following embodiments, the current value (voltage value) when in the "stable state" is expressed as a constant value. However, in reality, the current value (voltage value) fluctuates to some extent, and the term "stable state" also includes a state in which such fluctuations exist.

[0023] In this embodiment, a voltage is applied to the detection unit 5 after the light L1 emitted from the light emitting unit 4 passes through the hole 310 of the gear 31. When the holes 310 of the gear 31 overlap and become through, the light L1 reaches the detection unit 5 arranged opposite to the light emitting unit 4. However, the detection unit 5 is not applied with an input voltage (at Figure 5 No current is output until a detection pulse is input (e.g., a detection pulse is inputted in the detection section). Charge is accumulated in the parasitic capacitance. When a voltage is applied to the detection section 5 while the parasitic capacitance is charged, the detection section 5, which is a phototransistor PTr, outputs a current value that is different from the current value when the normal "steady state" light intensity is detected (the "steady state" current value, the ... Figure 5 In addition, in this embodiment, the output current value from the detection unit 5 is output to the control unit 20. In this embodiment, the control unit 20 performs AD conversion (in the case of the current value) of the current output from the detection unit 5 into a voltage value. Figure 5 etc.), through the comparator (in Figure 5 The voltage value is compared with a predetermined threshold value, and the control unit 20 determines whether it exceeds the threshold value.

[0024] Furthermore, the light emitting unit 4 and the detection unit 5 are arranged opposite to each other, and the arrangement pattern is not particularly limited as long as they are arranged in a positional relationship such that the detection unit 5 can receive the light L1 emitted from the light emitting unit 4 when the hole 310 is in a through state. Figure 1 and Figure 3A In FIG. 1 , the light emitting portion 4 is arranged on the auxiliary substrate 14 above the gear train mechanism, and the detection portion 5 is arranged on the main substrate 13 provided on the lower side in the thickness direction H and arranged at a position opposite to the light emitting portion 4. In contrast, in Figure 3B , an example is shown in which the detection portion 5 is arranged on the auxiliary substrate 14 above the gear train mechanism, and the light emitting portion 4 is arranged on the main substrate 13 provided on the lower side in the thickness direction H and arranged at a position facing the detection portion 5.

[0025] Furthermore, the components to be arranged on the substrate can be mounted at a position lower than the reference surface of the substrate by counterboring the surface of the main substrate 13. Figure 3C In FIG. 1 , an example is shown in which the detection unit 5 is arranged in the countersunk portion 132 formed on the main substrate 13. Figure 3D, an example is shown in which the light emitting unit 4 is arranged in the countersunk portion 132 formed on the main substrate 13. By providing the countersunk portion 132 in this way, it is possible to achieve space saving when installing the light emitting unit 4 and the detection unit 5. In addition, when the detection unit 5 is installed on the auxiliary substrate 14, Figure 3B and Figure 3D As shown, the electrode provided on the main light receiving surface 51 side of the detection unit 5 is electrically connected to the electrode portion 141 formed on the auxiliary substrate 14, and the secondary light receiving surface 52 of the detection unit 5 faces the light emitting unit 4. Figure 1 、 Figures 3A to 3D The drawings schematically illustrate the configuration to the extent necessary for explanation, and do not accurately illustrate the actual internal configuration of the timepiece 100 or the arrangement and number of the gears 31 constituting the train wheel mechanism.

[0026] In addition, in addition to this, Figure 2 As shown, the clock 100 includes a control unit 20 composed of a CPU (Central Processing Unit), a ROM (Read Only Memory) 21, and a RAM (Random Access Memory) 22. The control unit 20 performs various calculations in the analog electronic clock 1 and controls the overall operation. In this embodiment, the control unit 20 functions as a control unit for controlling the needle position detection operation. That is, the current value is output from the detection unit 5 to the control unit 20. In the control unit 20, it is converted into a voltage value, and the voltage value is obtained as a "current-based value" at a "prescribed timing". Here, the "prescribed timing" is a "current-based value", that is, in the embodiment, a value at which the "voltage value" becomes a "stable state" (at Figure 5 The timing is set to the time before the voltage is applied to the detection unit 5 (the value of the "a" level in the example). In practice, the timing is set to the time after a predetermined time has passed since the voltage was applied to the detection unit 5 (after the detection pulse was input). The "predetermined time" is, for example, approximately 3 ms. While the "predetermined time" is not limited to 3 ms, it is desirable to set it in advance to prevent variations in the results between each detection.

[0027] The control unit 20 then uses a comparator to determine whether this "current-based value" (in this embodiment, a voltage value converted from an AD conversion value) is above a predetermined threshold value, and performs hand position detection based on this determination. The threshold value for hand position detection is determined, for example, by the sum of the voltage value (AD conversion value) obtained by AD-converting the detection result (output current value) of the detection unit 5 when the light-emitting unit 4 is off, and the output inherent to the gear train mechanism. The determined threshold value is pre-stored in a storage unit such as ROM 21 or RAM 22 as the hand position detection threshold value corresponding to each hand 3.

[0028] In addition, the control unit 20 applies an input voltage to the light-emitting unit 4 to turn on the light-emitting unit 4, or applies an input voltage (input detection pulse, etc.) to the detection unit 5 to turn on the detection unit 5, etc., to control the turning on (ON) and off (OFF) of the light-emitting unit 4 and the detection unit 5. In addition, in the present embodiment, as described above, when detecting the needle position, the light-emitting unit 4, such as an LED, is illuminated before applying a voltage to the detection unit 5. That is, the voltage is applied to the detection unit 5 a predetermined time after the light-emitting unit 4 is illuminated. The extent of the predetermined time is determined appropriately, but as described above, this time is the time for charge to be accumulated in the parasitic capacitance, and is preferably the time for sufficient charge to be accumulated in the parasitic capacitance, for example, about 50 ms.

[0029] The ROM 21 is a nonvolatile memory that stores control programs for the timepiece 100 executed by the control unit 20, as well as operating programs related to various functions such as the hand position detection function. The ROM 21 also stores various data required for the hand position detection process, etc. The RAM 22 is a volatile memory that provides operating storage space for the control unit 20 and stores deployed programs, temporary data, etc. Furthermore, the RAM 22 stores information on the hand positions of the plurality of hands 3 (i.e., the second hand 3s, minute hand 3m, and hour hand 3h).

[0030] In addition, if Figure 2 As shown, the timepiece 100 includes a power supply unit 23 that supplies power to various parts of the timepiece 100 via the control unit 20, various circuits required for the timepiece 100 to realize the time display function (such as an oscillating circuit 24, a frequency dividing circuit 25, a timing circuit 26, a detection circuit 27, etc.), and an antenna 28, etc. In addition, the components mounted on the timepiece 100 are not limited to the components illustrated here. In addition, these control unit 20, ROM 21, RAM 22, oscillating circuit 24, frequency dividing circuit 25, timing circuit 26, detection circuit 27, etc. can also be installed on a circuit substrate such as a substrate (main substrate 13) to form an LSI (Large Scale Integration). In addition, the components such as the oscillating circuit 24, the frequency dividing circuit 25, the timing circuit 26, the detection circuit 27 are well-known structures, so their description is omitted here.

[0031] Next, refer to Figure 5 The operation of the clock 100 of this embodiment will be described in detail, and in particular, the hand position detection method will be described in detail. Figure 4To illustrate the existing needle position detection method. In addition, both the existing needle position detection and the needle position detection of the present embodiment are preferably performed after the needle has run and the damping action of the motor of the drive mechanism that causes the needle 3 to run has stabilized. In addition, both the existing needle position detection and the needle position detection of the present embodiment are performed, for example, by using as a threshold a value determined by summing the voltage value (AD conversion value) after AD conversion of the detection result (output current value) of the detection unit 5 when the light-emitting unit 4 is in a non-lit state and the output inherent in the gear train mechanism. In addition, in Figure 4 and Figure 5 In the figure, the time series is shown from left to right.

[0032] In the past, when detecting the needle position, Figure 4 As shown, first, at the time point C1, the phototransistor (at Figure 4 An input voltage (input detection pulse) is applied to the detection unit ("PTr") to turn it on. Then, at time point C2, after a sufficient time has passed since the application of the input voltage and the output of the phototransistor PTr as the detection unit has stabilized, an input voltage is applied to the light-emitting unit such as the LED to turn it on. In addition, the sufficient time required for the output of the phototransistor PTr to stabilize is, for example, about 20ms. Then, the value of the output current output by the phototransistor PTr based on the amount of light L1 detected is converted into a voltage value, and the voltage value is compared with a threshold value by a comparator (C3 to C4). And, based on the result of the comparison, if the voltage value exceeds the threshold value, the control unit determines that the hole is in a through-hole state, and if it does not exceed the threshold value, the control unit determines that the hole is not in a through-hole state.

[0033] In such a conventional method, the current-based value (e.g., voltage value after AD conversion) output from the phototransistor PTr at the C2 time point when the light-emitting unit such as the LED is turned on is a value of the "a" level corresponding to the light L1 emitted by the light-emitting unit. This is set as the current value (voltage value) based on the "steady state". Figure 4 As shown, the rise in the value of the "stable state" (the value of the "a" level) is small, and depending on the output of the light-emitting unit, it is possible that the value is erroneously judged to be below the threshold value even though the hole is actually through.

[0034] In contrast, in the method of this embodiment, if Figure 5As shown, first, when the light emitting portion 4 such as the LED is not lit, an input voltage (input detection pulse (1)) is applied to the phototransistor PTr as the detection portion 5 to turn it on. Then, the control portion 20 performs AD conversion on the output current value from the detection portion 5 to obtain a voltage value (AD conversion value). Then, the value determined by summing the AD conversion value and the output inherent in the wheel train mechanism is stored as a threshold in a storage portion such as RAM22. Next, when performing actual needle position detection, first, at time A1, an input voltage is applied to the light emitting portion 4 such as the LED to turn it on. Then, after a predetermined time (for example, about 50ms) has passed since the light emitting portion 4 such as the LED was lit (at Figure 5 A2 in the figure), the phototransistor as the detection unit 5 (at Figure 5 When the phototransistor PTr as the detection unit 5 outputs an output current value corresponding to the light amount of the detected light L1, the output current value is A / D converted.

[0035] Then, the control unit 20 obtains the AD conversion value (voltage value) as the "current-based value" output from the detection unit 5 at the time point A3 as the "predetermined timing". The "predetermined timing" is the timing before the "current-based value" becomes a "stable state" value. In addition, the "predetermined timing" is the timing after the "predetermined time" has passed since the voltage was applied to the detection unit 5. In this embodiment, the "predetermined time" that should have passed since the voltage was applied to the detection unit 5 is as follows: Figure 5 As shown, it is about 3ms. When the control unit 20 obtains the "value based on current" (voltage value), it compares the "value based on current" (voltage value) with the threshold value through the comparator (A3~A4). And, based on the result of the comparison, if the "value based on current" (voltage value) exceeds the threshold value, the control unit 20 determines that the hole 310 is in a through-state, and if it does not exceed the threshold value, the hole 310 is not in a through-state. In addition, Figure 5 In the example shown, at time A4, when the comparator's comparison ends, the LED of light-emitting section 4 is turned off, and the application of voltage to detection section 5 (input of detection pulses) is also stopped, causing it to turn off. The timing for turning off light-emitting section 4 and detection section 5 is not limited to this, but by turning off light-emitting section 4 and detection section 5 at time A4, when the comparator's comparison ends, unnecessary power consumption can be suppressed.

[0036] In this embodiment, during the period from when the light emitting unit 4 such as an LED is turned on to when an input voltage is applied to the phototransistor PTr as the detection unit 5, electric charge is accumulated in the parasitic capacitance, and thus Figure 5As shown, in the detection unit 5, which is a phototransistor PTr, when an input voltage is applied, due to transient response, a current with a value that is greatly amplified compared to the value of the current output by the phototransistor PTr (detection unit 5) when the light-emitting unit 4, such as an LED, is normally lit (i.e., the value of the output current at the "a" level, which is the value of the "steady state"). In addition, in this embodiment, the timing at which the control unit 20 obtains the "current-based value" (the voltage value after AD conversion) output from the detection unit 5 and compares it with the comparator is, as mentioned above, the timing at which about 3ms, which is the "predetermined time", has passed since the voltage was applied to the detection unit 5. Figure 5 1 and 2 show timings after the point in time at which the output current value (voltage value after AD conversion) from the phototransistor PTr reaches its peak.

[0037] However, in Figure 5 In the example, the "value based on the current" reaches the value of the "stable state" level "a" after the time point A4 when the comparison by the comparator is completed. During the period A3 to A4 when the comparator is performing the comparison, the voltage value of the "value based on the current" also greatly exceeds the value of the "stable state" level "a". Therefore, the control unit 20 will turn on the value of the "value based on the current" when the "value based on the current" reaches the value of the "stable state" ( Figure 5 The "current-based value" (voltage value after AD conversion) output from the detection unit 5 is obtained at a timing before the value of the "a" level shown). Therefore, even in the case where the output of the light-emitting unit 4 is slightly weak, and even in the case where the light L1 emitted by the light-emitting unit 4 is received by the secondary light-receiving surface 52 with relatively low light-receiving sensitivity as in the present embodiment, as long as the hole 310 is in a through state, a value exceeding the threshold value can be obtained with high accuracy, and the possibility of misjudging whether the hole 310 is in a through state is low. As a result, high-precision needle position detection can be performed. In addition, Figure 5 In the example, before starting the needle position detection, a pulse for removing the afterglow (i.e., applying an input voltage) of about 30 ms is input to the phototransistor PTr as the detection unit 5, and then the detection operation is started after waiting for a period of time (e.g., 50 ms). However, the input of the pulse for removing the afterglow and the subsequent waiting time after removing the afterglow can be omitted (in the example of FIG. Figure 5 The middle is WAIT after the afterglow effect is removed).

[0038] As described above, in this embodiment, the timepiece 100 includes a hand 3, a gear 31 provided corresponding to the hand 3 and having a hole 310, a detector 5 provided corresponding to the gear 31, and a control unit 20. The detector 5 is applied with a voltage after light L1 passes through the hole 310 of the gear 31. While the voltage is applied, the detector 5 detects the light L1 that has passed through the hole 310 of the gear 31 and outputs a current corresponding to the amount of light L1 detected. This causes charge to accumulate in the parasitic capacitance, and the detector 5 detects a current value significantly amplified compared to the normal "steady state" value due to a transient response. The control unit 20 then acquires this "current-based value" at a predetermined timing and detects the hand position based on whether the "current-based value" is above a predetermined threshold. Since this "predetermined timing" is before the "current-based value" reaches its "steady state" value, the "current-based value" can be acquired during the period when the value is high and compared with the threshold. This can prevent the needle position from being misjudged as not being in the through-state due to the “value based on the current” outputted from the detector 5 not exceeding the threshold value even though the needle is actually in the through-state, thereby enabling appropriate and highly accurate needle position detection.

[0039] Furthermore, by using the method of this embodiment, when a voltage is applied to the detection unit 5, the detection unit 5 immediately detects a current having a value significantly amplified compared to the value in the "steady state." Therefore, compared to conventional methods, the time required to illuminate the LED of the light-emitting unit 4 and the time required to apply a voltage to the phototransistor PTr of the detection unit 5 can be shortened, thereby reducing the power consumption required for hand position detection.

[0040] Furthermore, the "predetermined timing" is the time before the "current-based value" reaches the "a" level, which represents the "steady-state" value, and is the time after a predetermined period of time has elapsed since the voltage was applied to the detection unit 5. Therefore, while charge is accumulated in the parasitic capacitance, and the transient response causes the value to be significantly higher than the normal "steady-state" value, the "current-based value" output from the detection unit 5 can be compared with the threshold value. Furthermore, while the time period during which the "current-based value" exceeds the "steady-state" value is not very long, by ensuring that the time conditions for obtaining the value for comparison with the threshold are consistent, a comparison result with consistent conditions can be obtained.

[0041] Furthermore, the timepiece 100 of this embodiment further includes a light-emitting unit 4 that emits light L1 toward the detection unit 5 at a position opposite the detection unit 5. During hand position detection, the light-emitting unit 4 is illuminated before voltage is applied to the detection unit 5. This allows charge to accumulate in the parasitic capacitance during the period before voltage is applied to the detection unit 5, resulting in a high output value that is significantly amplified compared to the "steady state" value due to transient response. Furthermore, in this embodiment, voltage is applied to the detection unit 5 a predetermined time after the light-emitting unit 4 is illuminated. Consequently, sufficient charge is accumulated in the parasitic capacitance, allowing a value to be easily compared as a "current-based value" to determine whether the value exceeds a threshold.

[0042] In addition, the detection unit 5 of the present embodiment has a main light-receiving surface 51 with high light-receiving sensitivity and a secondary light-receiving surface 52 with lower light-receiving sensitivity than the main light-receiving surface 51. When an electrode is provided on the same side as the main light-receiving surface 51, the detection unit 5 is mounted on the substrate (e.g., the main substrate 13) in such a manner that the surface on the electrode side is opposite to the substrate (e.g., the main substrate 13). Therefore, if a printed circuit board having a circuit pattern is used as the substrate (e.g., the main substrate 13), the detection unit 5 as a phototransistor PTr or the like can be directly mounted on the surface of the substrate (e.g., the main substrate 13) through SMT (Surface Mount Technology), and the electrode portion 131 of the substrate (e.g., the main substrate 13) can be joined to the electrode of the detection unit 5. Therefore, there is no need to implement wire bonding, etc., and the detection unit 5 can be installed simply and space-savingly. In addition, the time and cost of implementing wire bonding, etc. can be reduced.

[0043] In other words, when the main light-receiving surface 51 is mounted on the substrate in an orientation relative to the substrate, although the detection sensitivity of the detection unit 5 will become lower, the accumulation of charge in the parasitic capacitance allows the detection unit 5 to detect a current with a value that is greatly amplified compared to the normal "steady state" value due to the transient response, which can fully compensate for the decrease in detection sensitivity.

[0044] Furthermore, in this embodiment, the "current-based value" acquired at a timing before reaching the "stable state" value (the value at level "a") is a value temporarily amplified by the parasitic capacitance accumulated by the light L1 striking the detection unit 5. Thus, even when the amount of light from the light-emitting unit 4 is low or the detection sensitivity of the detection unit 5 is low, the "current-based value" output from the detection unit 5 exceeds the threshold. This prevents erroneous determination that the device is not in the through-state, even though it is actually in the through-state.

[0045] Furthermore, in this embodiment, before applying a voltage (inputting a detection pulse) to the detection unit 5, an afterglow-effect elimination pulse for resetting the parasitic capacitance is input to the detection unit 5. This eliminates the influence of the charge accumulated in the parasitic capacitance before the light L1 emitted from the light emitting unit 4 reaches the detection unit 5.

[0046] [Second embodiment]

[0047] Reference Figures 6 to 8 The second embodiment of the clock, the hand position detection method and the program will be described. In the clock as the electronic clock of this embodiment, the light detected by the detection unit 5 (in Figure 6 、 Figure 7 The light L2 in the figure is natural light (external light) and does not include a light-emitting unit such as an LED. Since the structure is otherwise the same as that shown in the first embodiment, the following description will focus on the differences from the first embodiment. Regarding other structures, the same components are denoted by the same reference numerals and their descriptions are omitted.

[0048] like Figure 6 and Figure 7 As shown, the timepiece of this embodiment is similar to the first embodiment and includes a plurality of gears 31 stacked in the thickness direction H. A hole 310 is formed in at least some of the gears 31 and passes through in the thickness direction H. The gears 31 are rotated by the drive mechanism 30, and the holes 310 formed in the plurality of gears 31 overlap with each other at a predetermined time according to the rotation of the gears 31. Figure 6 As shown, a detection unit 5 is arranged below the position where the holes 310 formed in the plurality of gears 31 overlap each other. Figure 2 Detection unit 5s for the second hand, detection unit 5m for the minute hand, and detection unit 5h for the hour hand are shown in FIG. 1 . Except that no light-emitting unit is provided at the relative position of detection unit 5, the same as the first embodiment is used. Detection unit 5 is directly mounted on a substrate (e.g., main substrate 13) by SMT.

[0049] exist Figure 6 , the holes 310 are shown to be connected to each other in the thickness direction H of the timepiece 100, and the light L2 is shown to be connected to the holes 310 in the connected state. In this embodiment, the light L2 that passes through the holes 310 in the connected state is natural light L2 as described above, and the holes 310 in the connected state function as openings for taking in natural light (openings). In contrast, Figure 7 As shown, when the positions of the holes 310 formed in the plurality of gears 31 are misaligned (the openings for taking in natural light are closed), the light L2 from above is blocked by the gears 31 in the middle and cannot reach the detection unit 5 arranged on the substrate below (e.g., the main substrate 13). The remaining configuration is the same as that of the first embodiment, and therefore its description is omitted.

[0050] like Figure 8 As shown, when the needle position is detected using natural light L2 as in this embodiment, the gears 31 of the gear train mechanism are arranged at predetermined positions, and when the detection holes 310 of the gears 31 overlap with each other, they are in a through state (the opening for taking in natural light is open, for example, see FIG. Figure 6 ), natural light L2 enters the clock from the outside. Before starting the hand position detection, the control unit 20 first inputs the afterglow effect removal pulse (i.e., applies an input voltage) to the detection unit 5, which is the phototransistor PTr. The input of the afterglow effect removal pulse is, for example, about 30ms. And then, the waiting time after the afterglow effect is removed (in Figure 8 After the afterglow effect is removed (WAIT), about 50 ms are left. Then, at time B1, the control unit 20 applies input voltage (input detection pulse) to the detection unit 5 again for about 10 ms.

[0051] like Figure 8 As shown in FIG. 1 , the hole 310 for detection is maintained in a through-state before the input of the pulse to remove the influence of afterglow. Therefore, natural light L2 is incident from the through-state hole 310. And as the natural light L2 is incident, charge is accumulated in the parasitic capacitance of the detection unit 5, which is the phototransistor PTr. Then, when a voltage is applied (input detection pulse), the detection unit 5, which is the phototransistor PTr, detects a current of a value that is greatly amplified compared to the normal "steady state" value due to transient response, as shown in FIG. Figure 8 As shown, a high current value is output. The output current value is converted into a voltage value by AD, and the input voltage (input detection pulse) is applied to the detection unit 5 at the "predetermined timing" ( Figure 8 The control unit 20 obtains the "current-based value" (time point B2 in the figure) as a "current-based value." The comparator then compares the "current-based value" with a threshold value. As in the first embodiment, the "predetermined timing" referred to here is approximately 3 ms after the input voltage (input detection pulse) is applied to the phototransistor PTr serving as the detection unit 5. If the voltage value ("current-based value") is higher than the threshold value, the control unit 20 determines that the hole 310 is open. If it is lower than the threshold value, the control unit 20 determines that the hole 310 is not open.

[0052] Although it is conceivable that the amount of light L1 emitted by a light emitting unit such as an LED may be less than that of natural light L2, in this embodiment, by utilizing the transient response caused by the parasitic capacitance as described above, a value ( Figure 8 A value greatly amplified compared to the value at the “a” level in FIG. 1 is taken as the “value based on current”.

[0053] In this embodiment, in addition to the effects of the first embodiment, the following effects can also be obtained. That is, in this embodiment, the light L2 that passes through the hole 310 of the gear 31 and is detected by the detection unit 5 is natural light L2. Therefore, there is no need to configure a light-emitting unit such as an LED in the clock, which is conducive to space saving, and since there is no need for electricity to light the light-emitting unit, it is conducive to power saving. In addition, even in the case of needle position detection using natural light L2 with a relatively small amount of light, a value (current value or voltage value) that is greatly amplified compared to the value of the "steady state" can be obtained by using transient response as a "current-based value" and used for comparison with the threshold. Therefore, it is possible to determine with high precision whether the hole 310 is in a through state, and to avoid misjudgment in needle position detection.

[0054] Furthermore, if an electrode is provided on the same side of the detection unit 5 as the main light-receiving surface 51, even in the present embodiment utilizing natural light L2, SMT mounting can be employed, with the main light-receiving surface 51 facing the substrate (main substrate 13, etc.) and electrically connected to the electrode portion 131 on the substrate. As described above, by utilizing the transient response, a value (current value or voltage value) significantly amplified compared to the "steady state" value can be obtained as a "current-based value." Therefore, even when light is received by the secondary light-receiving surface 52, which has low light-receiving sensitivity, a "current-based value" at a level that provides no problem in comparison with the threshold value can be obtained.

[0055] Furthermore, although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit and scope of the present invention.

[0056] For example, in the first embodiment described above, Figure 5 As shown, before the output current value (voltage value) of the phototransistor PTr of the detection unit 5 becomes the value of the "stable state" (the value of the "a" level), the application of voltage to the LED of the light-emitting unit 4 and the input of the detection pulse (2) to the detection unit 5 are stopped. However, as long as the control unit obtains the current value (voltage value) and performs the comparator operation at a timing before the "current-based value" becomes the value of the "stable state" (the value of the "a" level), the timing of stopping the application of voltage to the LED of the light-emitting unit 4 and the input of the detection pulse (2) to the detection unit 5 is not limited to Figure 5 For example, Figure 9As shown, the control unit obtains the current value (voltage value) and performs comparator operation at a timing before the "current-based value" becomes the "stable state value" (the value of the "a" level), but the timing of stopping the application of voltage to the LED as the light-emitting unit 4 and inputting the detection pulse (2) to the detection unit 5 is the timing after the output current value (voltage value) of the phototransistor PTr as the detection unit 5 becomes the "stable state value" (the value of the "a" level) (at Figure 9 In addition, the timing of stopping the application of voltage to the LED as the light emitting unit 4 and the timing of stopping the input of the detection pulse (2) to the detection unit 5 may not be simultaneous, and the two timings may be staggered. Figure 9 In FIG. 1 , the processing before the time point A1 when the LED as the light emitting unit 4 is turned on is omitted from the figure.

[0057] In addition, in the timing diagram of the second embodiment described above, Figure 8 In the example shown in FIG1 , the application of voltage to the detection unit 5 (input of detection pulse) is stopped when the output current value (voltage value) of the phototransistor PTr reaches the value of the "steady state" (the value of the "a" level). However, the timing of stopping the application of voltage to the detection unit 5 (input of detection pulse) is not limited to the example shown in the figure. The timing of stopping the application of voltage to the detection unit 5 (input of detection pulse) can be after the end of the comparator operation, and can also be after the end of the comparator operation. Figure 8 For example, the application of voltage to the detection unit 5 (inputting a detection pulse) may be stopped immediately after the end of the comparator operation. By stopping the application of voltage at an early time, unnecessary power consumption can be suppressed.

[0058] In the above embodiment, a voltage value obtained by AD-converting the current value output from the phototransistor PTr as the detection unit 5 is used as the "current-based value" and compared with the threshold value. However, the "current-based value" and the threshold value are not limited to voltage values. For example, the current value output from the detection unit 5 may be used as the "current-based value" without converting it to a voltage value.

[0059] Although some embodiments of the present invention have been described above, the scope of the present invention is not limited to the above embodiments but includes the scope of the invention described in the claims and their equivalents.

Claims

1. An electronic clock, characterized in that: have: Needle; a gear, which is provided corresponding to the pin and has a hole; a detection unit provided corresponding to the gear, detecting light passing through the hole of the gear when a voltage is applied thereto, and outputting a current corresponding to the amount of the detected light; and a control unit that acquires a value based on the current output by the detection unit at a predetermined timing and detects the needle position of the needle based on a determination result of whether the value based on the current is equal to or greater than a predetermined threshold value; The predetermined timing is a timing before the value based on the current outputted by the detection unit becomes a value in a stable state.

2. The electronic timepiece according to claim 1, wherein: The value based on the current acquired at a timing before reaching the value in the steady state is a value temporarily amplified by parasitic capacitance accumulated by light irradiating the detection unit.

3. The electronic timepiece according to claim 2, wherein: Before applying a voltage to the detection unit, an afterglow effect removal pulse for resetting the parasitic capacitance is input to the detection unit.

4. The electronic timepiece according to any one of claims 1 to 3, characterized in that: The predetermined timing is a timing before the value based on the current reaches a stable value, and is a timing when a predetermined time has elapsed since a voltage was applied to the detection unit.

5. The electronic timepiece according to any one of claims 1 to 4, characterized in that: A light emitting unit for emitting light toward the detection unit is further provided at a position facing the detection unit. The control unit lights up the light emitting unit before applying a voltage to the detection unit during the needle position detection.

6. The electronic timepiece according to claim 3, wherein: The control unit applies voltage to the detection unit a predetermined time after the light emitting unit is turned on.

7. The electronic timepiece according to any one of claims 1 to 6, characterized in that: The light that passes through the hole of the gear and is detected by the detection unit is natural light.

8. The electronic timepiece according to any one of claims 1 to 7, characterized in that: The detection unit The invention comprises: a first surface having high light sensitivity and an electrode portion; and a second surface opposite to the first surface having lower light sensitivity than the first surface. The device is mounted on the substrate so that the first surface faces the substrate.

9. A needle position detection method, characterized in that: When a needle, a gear, and a detection unit are provided to detect the needle position, The needle position of the needle is detected based on a determination result of whether the current-based value outputted by the detection unit is equal to or greater than a predetermined threshold value, by acquiring the current-based value outputted by the detection unit at a predetermined timing. The predetermined timing is a timing before the value based on the current outputted by the detection unit becomes a stable value. Wherein, the gear is arranged corresponding to the needle and has a hole, The detection unit is provided corresponding to the gear, detects light passing through the hole of the gear when a voltage is applied thereto, and outputs a current corresponding to the amount of detected light.

10. A program, characterized in that Computer using a clock with hands, gears and a detection unit The needle position of the needle is detected based on a determination result of whether the current-based value outputted by the detection unit is equal to or greater than a predetermined threshold value, by acquiring the current-based value outputted by the detection unit at a predetermined timing. The predetermined timing is a timing before the value based on the current outputted by the detection unit becomes a stable value. Wherein, the gear is arranged corresponding to the needle and has a hole, The detection unit is provided corresponding to the gear, detects light passing through the hole of the gear when a voltage is applied thereto, and outputs a current corresponding to the amount of detected light.

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