Electronic timepiece, method for detecting position of hand, and program

Abstract

To detect the position of a hand accurately even with a small amount of light.SOLUTION: A timepiece 100 includes a hand 3, a gear 31 corresponding to the hand 3 and having a hole 310, a detection unit 5 corresponding to the gear 31 and detecting light passing through the hole 310 of the gear 31 when a voltage is applied and outputting a current according to the detected light amount, and a control unit 20 for acquiring a value based on the current output from the detection unit at a predetermined timing and detecting the position of a hand for the hand 3 on the basis of a determination result of whether the value based on the current is equal to or greater than a predetermined threshold. The predetermined timing is a timing before the value based on the current output from the detection unit becomes a value in a "steady state."SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Conventionally, there is known a technique for detecting the hand positions of an analog timepiece by detecting the light emitted by a light-emitting element such as an LED or natural light with a light-receiving element such as a phototransistor (see, for example, Patent Document 1). In conventional hand position detection, when a light-emitting element such as an LED is used, a voltage is applied to the light-receiving element before the light-emitting element is made to emit light, and the threshold value for hand position detection is determined when the output current from the light-receiving element is stable (stable period). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-284444 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with this conventional method, the power required to emit light from the light-emitting element must be increased in order to stably output a current exceeding the threshold from the light-receiving element, resulting in high power consumption. Also, if you try to detect the hand position using natural light without using a light-emitting element, depending on the environment, there may not be enough light to begin with, and it may be impossible to obtain an output current exceeding the threshold from the light-receiving element.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide an electronic timepiece, a hand position detection method, and a program that can accurately detect the hand position even with a small amount of received light. [Means for solving the problem]

[0006] In order to solve the above problems, the electronic timepiece according to the present invention comprises: The timekeeping device comprises a needle, a gear corresponding to the needle and having a hole, a detection unit corresponding to the gear and detecting light that passes through the hole in the gear when a voltage is applied and outputting a current corresponding to the amount of light detected, 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 relative to the needle based on the determination result of whether the value based on the current is equal to or greater than a predetermined threshold, wherein the predetermined timing is a timing before the value based on the current output by the detection unit reaches a steady-state value. [Effects of the Invention]

[0007] According to the present invention, it is possible to achieve an effect of detecting the hand position with high accuracy even with a small amount of received light. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a main part that schematically shows a portion related to hand position detection in a timepiece according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing the main control configuration of the timepiece according to the embodiment. [Figure 3] 3(a) to 3(d) are schematic cross-sectional views showing the positional relationship between a light-emitting unit and a detecting unit in the first embodiment. [Figure 4] 10 is a timing chart showing conventional hand position detection using a light-emitting unit. [Figure 5] 10 is a timing chart showing hand position detection in the present embodiment when a light emitting unit is used. [Figure 6] 10 is a cross-sectional view of a main part that schematically shows the relationship between the train wheel mechanism and the detection unit when the hole for detecting the hand position in a timepiece according to a second embodiment is in a through state. FIG. [Figure 7] 10 is a cross-sectional view of a main part that schematically shows the relationship between the train wheel mechanism and the detection unit when the hole for detecting the hand position of a timepiece according to a second embodiment is in a non-through state. FIG. [Figure 8]10 is a timing chart showing hand position detection in the present embodiment when natural light is used. [Figure 9] 10 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 OF THE INVENTION

[0009] Below, embodiments of an electronic timepiece, a hand position detection method, and a program according to the present invention will be described with reference to Figures 1 to 9. In the following, the electronic timepiece will be simply referred to as a "timepiece." The embodiments described below are subject to various technically preferable limitations for implementing the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

[0010] [First embodiment] A first embodiment of a timepiece 100, hand position detection method, and program will be described with reference to Figures 1 to 5. As shown in Figures 1 and 2, the electronic timepiece 100 of this embodiment is a timepiece that displays time in an analog format, and includes a hand 3, a gear 31 provided corresponding to the hand 3, a detection unit 5, and a control unit 20. In this embodiment, the hands 3 include a second hand 3s, a minute hand 3m, and an hour hand 3h. Note that the timepiece 100 is not limited to a three-hand type having three hands 3, and may also be a two-hand type having only a minute hand 3m and an hour hand 3h, for example.

[0011] Each hand 3 is attached to a center axis 32, and each is rotated around the center axis 32 by a drive mechanism 30 (second hand drive mechanism 30s, minute hand drive mechanism 30m, hour hand drive mechanism 30h in FIG. 2) to indicate the appropriate time. Each drive mechanism 30 includes a train wheel mechanism made up of gears 31, a motor (not shown) that operates the train wheel mechanism, and the like. Note that a motor may be provided for each hand 3, or a configuration may be such that one motor corresponds to multiple hands 3. When the main internal configuration of the timepiece 100 is viewed in cross section as shown in FIG. 1, the timepiece 100 includes, from the top in the thickness direction H (the vertical direction in FIG. 1, the axial direction of the center axis 32), a dial 11, a solar panel 12, a date indicator holder 33, multiple gears 31 that make up the train wheel mechanism, a circuit board (main board 13), and the like.

[0012] The gears 31 are stacked in the thickness direction H, and at least some of the gears 31 have holes 310 formed therethrough in the thickness direction H. The gears 31 are rotated by the drive mechanism 30, and the holes 310 formed in multiple gears 31 overlap each other at a predetermined time in response to the rotation of the gears 31. At this time, the holes 310 penetrate each other in the thickness direction H of the timepiece 100, allowing light ("light L1" in Figure 1 and other figures) to pass through the through holes 310. In this embodiment, the light L1 that penetrates the through holes 310 is light (emitted light L1) emitted by the light-emitting unit 4, which will be described later.

[0013] As shown in FIG. 1, above and below the position where the holes 310 formed in the multiple gears 31 overlap, the light-emitting units 4 (in FIG. 2, 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 the detection units 5 (in FIG. 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 so as to face each other. The position where the light-emitting unit 4 and the detection unit 5 face each other across the through-hole 310 is the detection position for the hand position in this embodiment. Note that the configurations of the light-emitting unit 4 and the detection unit 5 provided for each hand 3 (second hand 3s, minute hand 3m, hour hand 3h) are the same. For this reason, hereinafter, when simply referring to the "light-emitting unit 4," this includes 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 simply referring to the "detection unit 5," this includes 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.

[0014] The light-emitting unit 4 is a light-emitting element such as an LED (Light Emitting Diode), which is turned on and emits light when a predetermined voltage (input voltage) is applied. In the example shown in FIG. 1, the light-emitting unit 4 is mounted on an auxiliary board 14 disposed on the back side (lower side in the thickness direction H) of the dial 11 and the solar panel 12, with its light-emitting side facing the detection unit 5. The detection unit 5 is composed of a light-receiving element such as a phototransistor (denoted as "PTr" in FIG. 5, etc.). The detection unit 5 corresponds to the train wheel mechanism, which is composed of gears 31 and operates each hand 3, and is provided below the train wheel mechanism. Specifically, the detection unit 5 is disposed on the main board 13 in a position facing the light-emitting unit 4.

[0015] Furthermore, in this embodiment, the detection unit 5 has a main light-receiving surface 51 with high light sensitivity and a secondary light-receiving surface 52 with lower light sensitivity than the main light-receiving surface 51, located above and below in the thickness direction H. 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 a first surface with high light sensitivity and an electrode portion, and the secondary light-receiving surface 52 is a second surface opposite the main light-receiving surface 51, which is the first surface, and has lower light sensitivity than the main light-receiving surface 51. In this embodiment, the detection unit 5 is mounted on a substrate (main substrate 13) so that the electrode-side surface (the surface on the main light-receiving surface 51 side), which is the first surface, faces the substrate (e.g., main substrate 13). Electrode portions 131 are formed on the substrate (main substrate 13), and in the mounted state, the electrodes of the detection unit 5 are electrically connected to the electrode portions 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 route wiring from the electrodes and perform wire bonding; instead, the detection unit 5 is mounted directly on the substrate (main board 13) using SMT mounting. This allows the detection unit 5 to be made thinner, enabling it to be mounted in a small space. Furthermore, eliminating the need for wire bonding also reduces costs. Note that this means that the secondary light-receiving surface 52 of the detection unit 5 faces the light-emitting unit 4.

[0016] The detection unit 5 detects light L1 when a voltage (input voltage) is applied, and outputs a current corresponding to the amount of light L1 detected. The amount of light detected when the detection unit 5 simply receives light L1 emitted by the light-emitting unit 4 is defined as the amount of light in a "steady state." In the following embodiments, the value of the current value (voltage value) when it reaches a "steady state" is expressed as being a constant value, but in reality, the current value (voltage value) fluctuates to a certain extent, and the term "steady state" is intended to include a state in which such fluctuations occur.

[0017] In this embodiment, voltage is applied to the detection unit 5 after the emitted light L1 from the light-emitting unit 4 penetrates the hole 310 of the gear 31. When the holes 310 of the gear 31 overlap and form a penetration state, the emitted light L1 reaches the detection unit 5 disposed opposite the light-emitting unit 4. However, the detection unit 5 does not output current until an input voltage is applied (a detection pulse is input in FIG. 5 and other figures), and charge accumulates in the parasitic capacitance. When voltage is applied to the detection unit 5 with charge accumulated in the parasitic capacitance, the detection unit 5, which is a phototransistor PTr, outputs a current whose value is significantly amplified by a transient response compared to the current value when detecting the normal "steady state" light intensity (the "steady state" current value, the "a" level value shown in FIG. 5 and other figures). Note that 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 (shown as "AD" in Figure 5, etc.) to convert the current value (current value) output from the detection unit 5 into a voltage value, and the comparator (shown as "COMP" in Figure 5, etc.) operates to compare the voltage value with a predetermined threshold value, and the control unit 20 determines whether it exceeds the threshold value.

[0018] The light-emitting unit 4 and the detecting unit 5 are disposed opposite each other and are positioned such that the emitted light L1 from the light-emitting unit 4 can be received by the detecting unit 5 when the hole 310 is in a through state, and the arrangement pattern is not particularly limited. For example, FIGS. 1 and 3(a) show an example in which the light-emitting unit 4 is disposed on the auxiliary substrate 14 above the gear train mechanism, and the detecting unit 5 is disposed on the main substrate 13 provided below in the thickness direction H, in a position facing the light-emitting unit 4. In contrast, FIG. 3(b) shows an example in which the detecting unit 5 is disposed on the auxiliary substrate 14 above the gear train mechanism, and the light-emitting unit 4 is disposed on the main substrate 13 provided below in the thickness direction H, in a position facing the detecting unit 5.

[0019] Furthermore, components disposed on the main substrate 13 may be mounted at a lower position than the reference surface of the substrate by recessing the surface of the main substrate 13. For example, FIG. 3(c) shows an example in which the detection unit 5 is disposed in a recess 132 formed on the main substrate 13, and FIG. 3(d) shows an example in which the light-emitting unit 4 is disposed in a recess 132 formed on the main substrate 13. By providing the recess 132 in this manner, it is possible to save space when mounting the light-emitting unit 4 and the detection unit 5. Note that even when the detection unit 5 is mounted on the auxiliary substrate 14, as shown in FIGS. 3(b) and 3(d), 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. Note that Figure 1 and Figures 3(a) to (d) are schematic examples of the configuration to the extent necessary for explanation, and do not accurately show the internal configuration of the actual timepiece 100, the arrangement and number of gears 31 that make up the gear train mechanism, etc.

[0020] As shown in FIG. 2, the watch 100 also includes a control unit 20, which includes a central processing unit (CPU), a read-only memory (ROM) 21, and a random access memory (RAM) 22. The control unit 20 performs various calculations for the analog electronic watch and also controls and coordinates the overall operation. In this embodiment, the control unit 20 functions as a control unit that controls the hand position detection operation. Specifically, the detection unit 5 outputs a current value to the control unit 20. The control unit 20 converts this current value into a voltage value and acquires the voltage value as a "current-based value" at a "predetermined timing." Here, the "predetermined timing" refers to the timing before the "current-based value," i.e., the "voltage value" in this embodiment, reaches a "steady state" value (the "a" level value in FIG. 5, etc.). Furthermore, in practice, the timing refers to the elapse of a predetermined time after a voltage is applied to the detection unit 5 (after a detection pulse is input). The "predetermined time" is, for example, approximately 3 ms. While the "predetermined time" is not limited to 3 ms, it is preferable to set it to a fixed value to prevent variations in the results from one detection to another.

[0021] Then, the control unit 20 uses comparator operation to determine whether the "value based on the current" (in this embodiment, a voltage value that is an AD converted value) is equal to or greater than a predetermined threshold, and performs hand position detection based on the result of this determination. The threshold for hand position detection is determined, for example, by adding together a voltage value (AD converted value) obtained by AD converting the detection result (output current value) of the detection unit 5 when the light-emitting unit 4 is not lit, and an output specific to the gear train mechanism. The determined threshold is stored in a storage unit such as ROM 21 or RAM 22 as the hand position detection threshold corresponding to each hand 3, for example.

[0022] The control unit 20 also controls the ON / OFF of the light-emitting unit 4 and the detection unit 5, for example, by applying an input voltage to the light-emitting unit 4 to turn it ON, or by applying an input voltage (inputting a detection pulse, etc.) to the detection unit 5 to turn it ON. In this embodiment, as described above, when detecting the hand position, the light-emitting unit 4, which is an LED or the like, is turned on before applying voltage to the detection unit 5. In other words, voltage is applied to the detection unit 5 a predetermined time after the light-emitting unit 4 is turned on. The length of the predetermined time can be determined as appropriate, but as described above, this time is the time required for charge to accumulate in the parasitic capacitance, and is preferably a time sufficient for charge to accumulate in the parasitic capacitance, for example, approximately 50 ms.

[0023] ROM 21 is a non-volatile memory that stores the control program for the timepiece 100 executed by the control unit 20 and operation programs related to various functions such as the function of performing hand position detection processing. ROM 21 also stores various data necessary for hand position detection operations, etc. RAM 22 is a volatile memory that provides working memory space for the control unit 20 and stores expanded programs, temporary data, etc. RAM 22 also stores hand position information for the multiple hands 3 (i.e., second hand 3s, minute hand 3m, hour hand 3h), etc.

[0024] As shown in FIG. 2, the clock 100 also includes a power supply unit 23 that supplies power to each unit of the clock 100 via the control unit 20, various circuits (e.g., oscillator circuit 24, frequency divider circuit 25, timing circuit 26, detection circuit 27, etc.) necessary for the clock 100 to perform its time display function, and an antenna 28. The components mounted on the clock 100 are not limited to those illustrated here. The control unit 20, ROM 21, RAM 22, oscillator circuit 24, frequency divider circuit 25, timing circuit 26, detection circuit 27, etc. may be mounted on a circuit board such as the main board 13 to form an LSI (Large Scale Integration). The oscillator circuit 24, frequency divider circuit 25, timing circuit 26, detection circuit 27, etc. are well-known components, and therefore will not be described here.

[0025] Next, with reference to FIG. 5 and other figures, the operation of the timepiece 100 according to this embodiment, particularly the hand position detection method, will be described in detail. Before describing the hand position detection method according to this embodiment, a conventional hand position detection method will be described for comparison with FIG. 4. Note that both conventional hand position detection and hand position detection according to this embodiment are preferably performed after the hand has moved, after the damping operation of the motor of the drive mechanism that moves the hand 3 has settled. Furthermore, both conventional hand position detection and hand position detection according to this embodiment are performed using a threshold value determined by summing 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 an output specific to the gear train mechanism. Note that FIGS. 4 and 5 are shown chronologically from left to right.

[0026] Conventionally, when detecting the needle position, as shown in FIG. 4, an input voltage (a detection pulse is input) is first applied to a detection unit, which is a phototransistor (PTr in FIG. 4), at time C1 to turn it on. Then, at time C2, after a sufficient time has elapsed since the application of this input voltage for the output of the phototransistor PTr, which is the detection unit, to stabilize, an input voltage is applied to a light-emitting unit such as an LED to turn it on. Note that the sufficient time for the output of the phototransistor PTr to stabilize is, for example, approximately 20 ms. Next, the phototransistor PTr converts the output current value output according to the amount of detected light L1 into a voltage value, and a comparator compares this voltage value with a threshold value (C3-C4). If the comparison result shows that the voltage value exceeds the threshold value, the control unit determines that the hole is in a through state, and if the voltage value does not exceed the threshold value, the control unit determines that the hole is not in a through state.

[0027] In such a conventional method, the value based on the current output from the phototransistor PTr at the point C2 when the light-emitting element, such as an LED, lights up (for example, the voltage value after AD conversion) is the "a" level value corresponding to the light emitted by the light-emitting element L1. This value (voltage value) is defined as the "steady state" value based on the current. As shown in Figure 4, the "steady state" value (the "a" level value) increases only slowly, and depending on the output of the light-emitting element, it may be erroneously determined that the value does not exceed the threshold value even when the hole is actually open.

[0028] In contrast, in the method of this embodiment, as shown in FIG. 5 , first, while the light-emitting element 4 such as an LED is not lit, an input voltage is applied to the phototransistor PTr (detection pulse (1) is input) to turn it ON, which serves as the detection element 5. The control unit 20 then performs AD conversion on the output current value from the detection element 5 to obtain a voltage value (AD-converted value). A value determined by adding this AD-converted value and an output specific to the gear train mechanism is then stored as a threshold value in a storage unit such as the RAM 22. Next, when actually detecting the hand position, an input voltage is first applied to the light-emitting element 4 such as an LED at time A1 to turn it ON. Then, after a predetermined time (e.g., approximately 50 ms) has elapsed since the light-emitting element 4 such as an LED was turned ON (time A2 in FIG. 5 ), an input voltage is applied to the phototransistor (PTr in FIG. 5 ) serving as the detection element 5 to turn it ON (detection pulse (2) is input). When the phototransistor PTr (detection element 5) outputs an output current value corresponding to the amount of light L1 detected, the output current value is AD-converted.

[0029] Then, the control unit 20 acquires this AD-converted value (voltage value) as the “value based on current” output from the detection unit 5 at time A3, which is the “predetermined timing.” The “predetermined timing” is the timing before the “value based on current” becomes a “steady state” value. The “predetermined timing” is the timing when a “predetermined time” has elapsed since the application of voltage to the detection unit 5. In this embodiment, the “predetermined time” that should elapse since the application of voltage to the detection unit 5 is approximately 3 ms, as shown in FIG. 5 . After acquiring the “value based on current” (voltage value), the control unit 20 compares this “value based on current” (voltage value) with a threshold value using a comparator (A3-A4). Then, if the “value based on current” (voltage value) exceeds the threshold value as a result of the comparison, the control unit 20 determines that the hole 310 is in a through state. If the “value based on current” (voltage value) does not exceed the threshold value, the control unit 20 determines that the hole 310 is not in a through state. 5, the LED that is the light-emitting unit 4 is turned off at time A4 when the comparison in the comparator is completed, and the application of voltage to the detection unit 5 (input of the detection pulse) is also stopped and turned off. The timing for turning off the light-emitting unit 4 and the detection unit 5 is not limited to this, but by turning off the light-emitting unit 4 and the detection unit 5 at time A4 when the comparison in the comparator is completed, unnecessary power consumption can be reduced.

[0030] In this embodiment, charge accumulates in the parasitic capacitance during the period from when the light-emitting element 4, such as an LED, is turned on until an input voltage is applied to the phototransistor PTr, which is the detection element 5. As a result, as shown in FIG. 5 , when an input voltage is applied, the detection element 5, which is the phototransistor PTr, outputs a current that is significantly amplified in transient response compared to the current value normally output by the phototransistor PTr (detection element 5) when the light-emitting element 4, such as an LED, is turned on (i.e., the output current value at level "a," which is the "steady state" value). Note that in this embodiment, the control unit 20 acquires the "current-based value" (voltage value after AD conversion) output from the detection element 5 and compares it with the comparator when, as described above, approximately 3 ms, which is the "predetermined time," has elapsed since the application of voltage to the detection element 5. As shown in FIG. 5 , this is the timing after the peak of the output current value (voltage value after AD conversion) from the phototransistor PTr.

[0031] However, in FIG. 5 , the “current-based value” reaches the “a” level, which is the “steady state” value, after the A4 point when the comparison by the comparator ends. Even during the A3-A4 period when the comparison by the comparator is being performed, the voltage value, which is the “current-based value,” remains significantly above the “a” level, which is the “steady state” value. Therefore, the control unit 20 acquires the “current-based value” (the voltage value after AD conversion) output from the detection unit 5 before the “current-based value” reaches the “steady state” value (the “a” level shown in FIG. 5 ). Therefore, even if the output of the light-emitting unit 4 is somewhat weak, or even if the emitted light L1 from the light-emitting unit 4 is received by the secondary light-receiving surface 52, which has relatively low light-receiving sensitivity, as in this embodiment, if the hole 310 is in a through state, a value exceeding the threshold can be obtained with high accuracy, reducing the risk of erroneously determining whether the hole 310 is in a through state. This enables highly accurate needle position detection. Note that FIG. 5 illustrates a case in which an afterglow effect removal pulse is input (i.e., an input voltage is applied) to the phototransistor PTr, which is the detection unit 5, for about 30 ms before starting hand position detection, and then the detection operation starts after waiting for a while (for example, 50 ms), but the input of the afterglow effect removal pulse and the subsequent waiting time after the afterglow effect removal (WAIT after afterglow effect removal in FIG. 5) may be omitted.

[0032] As described above, in this embodiment, the timepiece 100 includes a hand 3, a gear 31 having a hole 310 corresponding to the hand 3, a detection unit 5 corresponding to the gear 31, and a control unit 20. The detection unit 5 is applied with a voltage after light L1 penetrates the hole 310 of the gear 31. When the voltage is applied, the detection unit 5 detects light L1 that penetrates the hole 310 of the gear 31 and outputs a current corresponding to the amount of detected light L1. This causes charge to accumulate in the parasitic capacitance, and the detection unit 5 detects a current whose value is significantly amplified in a transient response compared to the normal "steady state" value. The control unit 20 then acquires this "current-based value" at a predetermined timing and performs hand position detection based on the results of determining whether the "current-based value" is equal to or greater than a predetermined threshold value. This "predetermined timing" occurs before the "current-based value" reaches the "steady state" value, so the "current-based value" can be acquired while it is still high and compared with the threshold value. This prevents the "value based on current" output from the detection unit 5 from exceeding the threshold value, which could lead to a false judgment that the needle is not in a penetrating state even though it is actually in the penetrating state, thereby enabling appropriate and highly accurate needle position detection.

[0033] Furthermore, by using the method of this embodiment, as soon as a voltage is applied to the detection unit 5, a current whose value is significantly amplified compared to the "steady state" value is detected by the detection unit 5. Therefore, compared to conventional methods, the time for which the LED, which is the light-emitting unit 4, is turned on and the time for which a voltage is applied to the phototransistor PTr, which is the detection unit 5, can be shortened, making it possible to reduce the power consumption required for hand position detection.

[0034] Furthermore, the "predetermined timing" is the timing before the "value based on the current" reaches the "a" level, which is the "steady state" value, and is the timing when a predetermined time has elapsed since the application of voltage to the detection unit 5. Therefore, the "value based on the current" output from the detection unit 5 can be compared with the threshold value while charge is accumulated in the parasitic capacitance and the transient response indicates a value that is significantly amplified compared to the normal "steady state" value. Furthermore, although the time during which the "value based on the current" indicates a value greater than the "steady state" value is not very long, by aligning the temporal conditions for obtaining the value to be compared with the threshold, comparison results can be obtained that are consistent across conditions.

[0035] The timepiece 100 of this embodiment also includes a light-emitting unit 4 facing the detection unit 5, which emits light L1 toward the detection unit 5. When detecting the hand position, the light-emitting unit 4 is turned on before voltage is applied to the detection unit 5. This allows charge to accumulate in the parasitic capacitance before voltage is applied to the detection unit 5, resulting in a transient response with a high output value that is significantly amplified compared to the "steady state" value. In this embodiment, voltage is applied to the detection unit 5 a predetermined time after the light-emitting unit 4 is turned on. As a result, sufficient charge accumulates in the parasitic capacitance, making it possible to obtain a "current-based value" that is easy to compare to determine whether it exceeds a threshold value.

[0036] Furthermore, the detection unit 5 of this embodiment has a primary light-receiving surface 51 with high light-receiving sensitivity and a secondary light-receiving surface 52 with lower light-receiving sensitivity than the primary light-receiving surface 51. When an electrode is located on the same side as the primary light-receiving surface 51, the detection unit 5 is mounted on a substrate (e.g., main substrate 13) with the electrode-side surface facing the substrate (e.g., main substrate 13). Therefore, if a printed circuit board with a circuit pattern is used as the substrate (e.g., main substrate 13), the detection unit 5, such as a phototransistor PTr, can be directly mounted on the surface of the substrate (e.g., main substrate 13) using SMT (Surface Mount Technology), and the electrode portion 131 of the substrate (e.g., main substrate 13) can be bonded to the electrode of the detection unit 5. This eliminates the need for wire bonding and allows the detection unit 5 to be mounted simply and in a space-saving manner. This also reduces the effort and cost required for wire bonding and other processes. In other words, if the main light receiving surface 51 is mounted on the substrate in a direction facing the substrate, the detection sensitivity of the detection unit 5 will be reduced, but by accumulating charge in the parasitic capacitance and having the detection unit 5 detect a current whose value is significantly amplified in the transient response compared to the normal "steady state" value, it is possible to fully compensate for the reduction in detection sensitivity.

[0037] Furthermore, in this embodiment, the "value based on current" acquired at a timing before the "steady state" value (value at level "a") is reached is a value temporarily amplified by the parasitic capacitance that accumulates when light L1 hits the detection unit 5. As a result, even if the amount of light from the light-emitting unit 4 is small or the detection sensitivity of the detection unit 5 is low, the "value based on current" output from the detection unit 5 exceeds the threshold value. This makes it possible to prevent a false determination that the light is not in a through state when it is actually in a through state.

[0038] Furthermore, in this embodiment, before applying a voltage (inputting a detection pulse) to the detection unit 5, an afterglow effect removal pulse for resetting the parasitic capacitance is input to the detection unit 5. This makes it possible to eliminate the effect of charges accumulated in the parasitic capacitance before the emitted light L1 from the light-emitting unit 4 hits the detection unit 5.

[0039] [Second embodiment] A second embodiment of a timepiece, a hand position detection method, and a program will be described with reference to Figures 6 to 8. In the electronic timepiece of this embodiment, the light detected by the detection unit 5 ("light L2" in Figures 6 and 7) is natural light (external light), and the watch does not include a light-emitting unit such as an LED. Note that other aspects are the same as the configuration shown in the first embodiment, so the following will particularly describe the differences from the first embodiment, and in other configurations, the same components will be assigned the same reference numerals and their description will be omitted.

[0040] As shown in FIGS. 6 and 7, the timepiece of this embodiment, like the first embodiment, has multiple gears 31 stacked in the thickness direction H, and at least some of the gears 31 have holes 310 formed therethrough in the thickness direction H. The gears 31 are rotated by a drive mechanism 30, and the holes 310 formed in the multiple gears 31 overlap each other at a predetermined time in response to the rotation of the gears 31. As shown in FIG. 6, below the position where the holes 310 formed in the multiple gears 31 overlap, detection units 5 (in FIG. 2, detection unit 5s for the second hand, detection unit 5m for the minute hand, and detection unit 5h for the hour hand) are located. Similar to the first embodiment, except that no light-emitting unit is provided opposite the detection unit 5, the detection unit 5 is directly mounted on a board (e.g., main board 13) by SMT.

[0041] FIG. 6 shows the holes 310 penetrating each other in the thickness direction H of the watch 100, with light L2 penetrating through the through-holes 310. In this embodiment, the light L2 penetrating the through-holes 310 is natural light L2, as described above, and the through-holes 310 function as openings for letting in natural light (open openings). In contrast, as shown in FIG. 7, if the holes 310 formed in multiple gears 31 are misaligned (the openings for letting in natural light are closed), the light L2 from above is blocked by the gears 31 along the way and does not reach the detection unit 5 located on the substrate below (for example, the main substrate 13). The rest of the configuration is the same as in the first embodiment, and therefore a description thereof will be omitted.

[0042] As shown in FIG. 8, when hand position detection is performed using natural light L2, as in this embodiment, gears 31 of the gear train mechanism are positioned in a predetermined position. When the detection holes 310 of each gear 31 overlap, a through-hole state (the opening for natural light entry is open, see, for example, FIG. 6 ) is formed, and natural light L2 enters the watch from the outside. Before starting hand position detection, control unit 20 first inputs an afterglow effect removal pulse (i.e., applies an input voltage) to detection unit 5, which is phototransistor PTr. The input of the afterglow effect removal pulse lasts, for example, about 30 ms. Then, after a waiting time of about 50 ms after afterglow effect removal (WAIT after afterglow effect removal in FIG. 8 ), control unit 20 again applies an input voltage (inputs a detection pulse) to detection unit 5 for about 10 ms at time B1.

[0043] As shown in FIG. 8 , the detection hole 310 remains open even before the afterglow effect removal pulse is input, allowing natural light L2 to enter through the open hole 310. As natural light L2 enters, charge accumulates in the parasitic capacitance of the detection unit 5, which is the phototransistor PTr. When a voltage is applied (a detection pulse is input), the detection unit 5, which is the phototransistor PTr, detects a current whose value is significantly amplified compared to the normal “steady state” value due to a transient response, and outputs a high current value, as shown in FIG. 8 . The output current value is converted to a voltage value by analog-to-digital conversion and acquired by the control unit 20 as a “value based on the current” at a “predetermined timing” (time B2 in FIG. 8 ) after the input voltage is applied (a detection pulse is input) to the detection unit 5. The “value based on the current” is then compared with a threshold value by a comparator. As in the first embodiment, the “predetermined timing” here refers to a timing approximately 3 ms after the input voltage is applied (a detection pulse is input) to the phototransistor PTr, which is the detection unit 5. If the voltage value ("value based on current") is higher than the threshold value, the control unit 20 determines that the hole 310 is in a through state, and if it is lower than the threshold value, it determines that the hole 310 is not through.

[0044] It is conceivable that the amount of light produced by natural light L2 is less than that produced by light emitted by a light-emitting element such as an LED L1. However, in this embodiment, by utilizing the transient response due to parasitic capacitance as described above, a value that is significantly amplified compared to the "steady state" value (the value at "a" level in FIG. 8) can be obtained as the "value based on current."

[0045] In addition to the effects of the first embodiment, this embodiment can achieve the following effects. Specifically, in this embodiment, the light L2 that penetrates 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 install a light-emitting unit such as an LED inside the watch, contributing to space savings. Furthermore, since no power is required to light the light-emitting unit, power savings are also achieved. Even when detecting the hand position using natural light L2, which has a relatively low intensity, a value (current value or voltage value) that is significantly amplified compared to the "steady state" value can be obtained by utilizing a transient response as a "current-based value" and used for comparison with a threshold value. Therefore, it is possible to accurately determine whether the hole 310 is penetrated, thereby avoiding erroneous judgments in hand position detection.

[0046] Note that, when an electrode is provided on the same side as the primary light-receiving surface 51 of the detection unit 5, even in the present embodiment that uses natural light L2, SMT mounting may be used in which the primary light-receiving surface 51 is placed opposite a substrate (such as the primary substrate 13) and electrically connected to the electrode unit 131 on the substrate. As described above, by utilizing the transient response, a value (current value or voltage value) that is significantly amplified compared to the "steady state" value can be obtained as the "value based on current." Therefore, even when light is received by the secondary light-receiving surface 52, which has low light-receiving sensitivity, a "value based on current" at a level that does not pose a problem when compared with a threshold value can be obtained.

[0047] Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments and that various modifications are possible without departing from the spirit of the present invention.

[0048] 5, the application of voltage to the LED serving as the light-emitting unit 4 and the input of detection pulse (2) to the detection unit 5 are stopped before the output current value (voltage value) of the phototransistor PTr serving as the detection unit 5 reaches the "steady state" value (the "a" level value). However, it is sufficient for the control unit to acquire the current value (voltage value) and perform comparator operation at the "timing before the "value based on current" reaches the "steady state" value (the "a" level value), and the timing for stopping the application of voltage to the LED serving as the light-emitting unit 4 and the input of detection pulse (2) to the detection unit 5 is not limited to the timing shown in FIG. For example, as shown in FIG. 9, the control unit acquires a current value (voltage value) and performs comparator operation at a timing before the "value based on the current" becomes the "steady state" value (the "a" level value). However, the application of voltage to the LED serving as the light-emitting unit 4 and the input of the detection pulse (2) to the detection unit 5 may be stopped at a timing after the output current value (voltage value) of the phototransistor PTr serving as the detection unit 5 becomes the "steady state" value (the "a" level value) (time A5 in FIG. 9). Furthermore, the timing of stopping the application of voltage to the LED serving as the light-emitting unit 4 and the timing of stopping the input of the detection pulse (2) to the detection unit 5 do not have to be simultaneous, and the two timings may be offset from each other. Note that in FIG. 9, the processes performed before time A1 when the LED serving as the light-emitting unit 4 is turned on are not shown.

[0049] 8, which is a timing chart for the second embodiment, the application of voltage to the detection unit 5 (input of detection pulses) is stopped when the output current value (voltage value) of the phototransistor PTr reaches a "steady state" value (value at level "a"). However, the timing for stopping the application of voltage to the detection unit 5 (input of detection pulses) is not limited to the illustrated example. The timing for stopping the application of voltage to the detection unit 5 (input of detection pulses) may be any timing as long as it is after the comparator operation is completed, and may be any timing prior to time B3 in FIG. 8. For example, the application of voltage to the detection unit 5 (input of detection pulses) may be stopped immediately after the comparator operation is completed. By stopping the application of voltage at an earlier point in time, unnecessary power consumption can be reduced.

[0050] In the above embodiment, the current value output from the phototransistor PTr, which is the detection unit 5, is converted into an AD-converted voltage value, which is used as the "current-based value," and this voltage value is compared with the threshold value. However, the "current-based value" and the threshold value are not limited to being voltage values. For example, the current value output from the detection unit 5 may be used as the "current-based value" without being converted into a voltage value.

[0051] Although several embodiments of the present invention have been described above, the scope of the present invention is not limited to the above-described embodiments, but includes the scope of the invention described in the claims and its equivalents. [Explanation of symbols]

[0052] 3 hands, 5 detection unit, 20 control unit, 31 gear, 100 clock (electronic clock), 310 hole, L1, L2 light,

Claims

1. Needles and a gear provided corresponding to the needle and having a hole; a detection unit provided corresponding to the gear, which detects light passing through a hole in the gear when a voltage is applied, and outputs a current corresponding to the amount of light detected; a control unit that acquires a value based on the current output by the detection unit at a predetermined timing and detects the position of the hands based on a determination result of whether the value based on the current is equal to or greater than a predetermined threshold value; Equipped with the predetermined timing is a timing before a value based on the current output by the detection unit reaches a steady state value. An electronic watch characterized by:

2. The value based on the current acquired at a timing before the steady-state value is a value temporarily amplified by parasitic capacitance accumulated when light is incident on the detection unit.

2. The electronic watch according to claim 1, wherein the electronic watch is a clock.

3. before applying a voltage to the detection unit, inputting an afterglow effect removal pulse to the detection unit to reset the parasitic capacitance; 3. The electronic timepiece according to claim 2.

4. the predetermined timing is a timing before the value based on the current becomes a steady-state value and a timing when a predetermined time has elapsed since a voltage was applied to the detection unit.

2. The electronic watch according to claim 1, wherein the electronic watch is a clock.

5. a light emitting unit that emits light toward the detection unit, the light emitting unit being located opposite the detection unit; When detecting the hand position, the control unit turns on the light emitting unit before applying a voltage to the detection unit.

2. The electronic watch according to claim 1, wherein the electronic watch is a clock.

6. the control unit applies a voltage to the detection unit a predetermined time after turning on the light-emitting unit.

6. The electronic watch according to claim 5, wherein the electronic watch is a clock.

7. The light that passes through the hole of the gear and is detected by the detection unit is natural light.

2. The electronic watch according to claim 1, wherein the electronic watch is a clock.

8. The detection unit a first surface having high light-receiving sensitivity and having an electrode portion; and a second surface opposite to the first surface, having lower light-receiving sensitivity than the first surface; The device is mounted on the substrate so that the first surface faces the substrate.

2. The electronic watch according to claim 1, wherein the electronic watch is a clock.

9. Needles and a gear provided corresponding to the needle and having a hole; a detection unit provided corresponding to the gear, which detects light passing through a hole in the gear when a voltage is applied, and outputs a current corresponding to the amount of light detected; When detecting the hand position, a value based on the current output by the detection unit is acquired at a predetermined timing, and a hand position detection is performed on the hand based on a determination result of whether or not the value based on the current is equal to or greater than a predetermined threshold value; the predetermined timing is a timing before a value based on the current output by the detection unit reaches a steady state value. A method for detecting hand position.

10. Needles and a gear provided corresponding to the needle and having a hole; a detection unit provided corresponding to the gear, which detects light passing through a hole in the gear when a voltage is applied, and outputs a current corresponding to the amount of light detected; a clock computer comprising: a value based on the current output by the detection unit is acquired at a predetermined timing, and a hand position detection is performed for the hand based on a determination result of whether or not the value based on the current is equal to or greater than a predetermined threshold value; the predetermined timing is a timing before a value based on the current output by the detection unit reaches a steady state value. A program characterized by:

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