JPH08201537A - Hand-position detection device of wristwatch - Google Patents

Abstract

PURPOSE: To provide the hand-position detection device of a wristwatch. CONSTITUTION: A capacitor for detection of hand positions is constituted of hands, for a wristwatch, constituted as electrodes on one side and of electrodes formed an a dial as electrodes on the other side. When a change in the capacitance of the capacitor for detection of the hand positions is detected, positions of the hands are detected. An hour hand 102 and a minute hand 101 which constitute the hands are arranged respectively on hand shafts whose rotation center is identical, a small second hand 106 is arranged on a second-hand shaft which is arranged in a position which is different from the hand shafts for the hour hand and the minute hand, and the electrodes on the dial are constituted separately for the hour hand and the small second hand. Consequently, the position of a second hand can be detected easily.

Description

Detailed Description of the Invention

[0001]

[Industrial field of application] Using the wristwatch pointer as one electrode,
The present invention also relates to a device for detecting the position of the pointer by forming the other electrode on the dial and detecting a change in the capacitance of the capacitor formed by the pointer and the electrode of the dial.

[0002]

2. Description of the Related Art A plan view of a dial of a pointer display type electronic timepiece disclosed in JP-A-62-222183 is shown in FIG.
Shown in Reference numeral 301 is a minute hand of the hands for time display, and 302 is an hour hand of the hands for time display. On the dial plate 303, a minute hand position detecting transparent electrode 304 formed by dividing the dial plate 303 in the circumferential direction, and an hour hand position detecting formed by dividing the dial plate 303 in the circumferential direction. When there is a transparent electrode 305 and the minute hand of 301 comes on the minute electrode position detecting transparent electrode 304, the capacitance between the minute hand 301 and the minute hand position detecting transparent electrode 304 increases. When the volume is maximally increased, the minute hand is detected as being in that position. The detection of the hour hand position is also the same.

[0003]

However, in the above-mentioned conventional example, since the second hand and the second hand position detecting transparent electrode are not provided on the dial plate 303, the second hand position cannot be detected. A case in which the timepiece is a middle three-hand type timepiece having a second hand and a transparent electrode for detecting the second hand position on the dial plate 303 will be described. In the middle three-hand type timepiece, the distance between the second hand position detecting transparent electrode and the second hand on the transparent electrode is larger than the distance of the minute hand 301 or the hour hand 302, and the width of the second hand is 301 minutes. Alternatively, it becomes smaller than the width of the hour hand 302, and as can be seen from the capacitance C0 between the pointer and the transparent electrode for the pointer shown in Equation 1, even if the second hand comes over the transparent electrode for the second hand, the second hand and the transparent electrode for the second hand are transparent. The increase in the capacitance between the electrodes is smaller than the increase in the capacitance between the hour and minute hands 302 and 301 and the transparent electrodes 305 and 304 for the hour and minute hands. The second hand shaft is a thin shaft that passes through the hour wheel and minute wheel shafts of the hour wheel and the second wheel.
Therefore, when attaching the second hand to the shaft, it is quite difficult to attach the second hand horizontally, and a slight blur occurs. Therefore, since the deflection width of the tip of the second hand is the largest, if you try to form a capacitance between the tip of the second hand and the electrode of the dial, it will be difficult to obtain a stable capacitance value due to the influence of the deflection of the second hand, It was difficult to detect the pointer position by detecting the capacitance change used.

[0004]

[Equation 1] C0 = ε0 · S / d

Here, C0 is the capacitance between the pointer and the transparent electrode for the pointer, ε0 is the dielectric constant of the vacuum, S is the facing area between the pointer and the transparent electrode for the pointer, and d is the distance between the pointer and the transparent electrode for the pointer. Is.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a device for accurately detecting the positions of the hour hand, minute hand, and second hand of a wristwatch.

[0007]

[Means for Solving the Problems] A wristwatch pointer constituted as one electrode and an electrode formed on a dial as the other electrode constitute a pointer position detecting capacitor,
In the device that detects the position of the pointer by detecting the change in the capacitance of the pointer position detection capacitor,
The hour hand and the minute hand constituting the pointer are respectively arranged on the pointer axes having the same center of rotation, and the second hand is
The hour hand and the pointer axis of the minute hand are arranged on a second hand axis arranged at a different position, and the electrodes on the dial are configured separately for the hour and minute hands and the second hand. Characterize.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of the dial according to this embodiment.
Reference numeral 1 is a minute hand of the time display hands, and 102 is an hour hand of the time display hands. On the dial plate 103, there are a minute hand position detecting transparent electrode 104 and an hour hand position detecting transparent electrode 105 for detecting the 0:00 position, and a small second hand 106 for displaying time is an hour hand and a minute hand shaft 107. Is a small second hand attached to another shaft 108, and the small second hand position detecting transparent electrode 109 is provided at a position where the 0 second position of the small second hand can be detected.

Since the small second hand 106 for displaying the time is attached to a shaft 108 different from the hour hand and minute hand shaft 107, the small second hand 106 on the transparent electrode 109 for detecting the small second hand position and the transparent second for detecting the small second hand position. The distance between the electrodes 109 can be made smaller than the distance between the minute hand 101 and the hour hand 102. On the other hand, the width of the small second hand 106 is smaller than the widths of the minute hand 101 and the hour hand 102, but as can be seen from the above formula 1, the capacitance between the pointer and the transparent electrode for detecting the pointer is equal to that of the pointer and the pointer. Since it is proportional to the facing area S of the transparent electrode for display and inversely proportional to the distance d between the pointer and the transparent electrode for detecting the pointer, the small second hand 10
The increase in the capacitance when 6 comes on the transparent electrode 109 for detecting the small second hand can be made approximately the same as the increase in the capacitance of the minute hand or the hour hand. Not only the position of the minute hand 101 and the hour hand 102 but also the position of the small second hand 106 can be detected.

FIG. 2 shows a pointer position detecting means. The clock circuit 201 is composed of a pointer position detecting capacitor connecting means 20.
3 outputs the output A, and the pointer position detecting capacitor connecting means 203 has three pointer positions formed by the hour hand 102, the minute hand 101, the small second hand 106 and the three electrodes 105, 104 and 109 of the dial respectively. One of the detecting capacitors
These are connected in parallel to an RC oscillation circuit 202 composed of inverters I1 and I2, a resistor Rt that determines an oscillation frequency, a capacitor Ct, and a current limiting resistor Rs. RC
The oscillation frequency f of the oscillator circuit 202 is expressed by the following equation 2.

[0011]

[Formula 2] f = 1 / (2.2 · Rt · (Ct + Cd))

Here, Cd is the capacitance of the pointer position detecting capacitor. According to the equation 2, the pointer position detecting means 204 detects each of the pointer positions where the oscillation frequency of the RC oscillation circuit 202 is the minimum from the output B of the RC oscillation circuit 202, and the output C of the pointer position detecting means 204 is the above-mentioned. Input to the clock circuit 201, and the clock circuit 201 outputs the hand movement signal D to the pointer drive circuit 205.

[0013]

As described in the above detailed description, according to claim 1 of the appended claims, by making the second hand independent of the hour and minute hands, it can be made thicker than the middle three-hand type second hand shaft. Therefore, the deflection of the second hand can be reduced, and since there is no hour / minute hand, the second hand and the dial plate electrode can be brought closer to each other, so that a stable capacitance value can be obtained. Therefore,
Detecting the pointer position has become easier.

[Brief description of drawings]

FIG. 1 is a plan view of a dial according to the present invention.

FIG. 2 is a pointer position detecting method of the present invention.

FIG. 3 is a plan view of a dial of a conventional pointer display type electronic timepiece.

[Explanation of symbols]

 101 minute hand 102 hour hand 106 small second hand 104 transparent electrode for minute hand position detection 105 transparent electrode for hour hand position detection 109 transparent electrode for small second hand position detection 202 RC oscillator circuit 203 pointer position detection capacitor connection means 204 pointer position detection means

Claims (1)

[Claims] 1. A capacitor for detecting the position of a pointer comprises a pointer of a wristwatch, which is configured as one electrode, and an electrode formed on a dial as the other electrode, and the electrostatic capacitance of the capacitor for detecting the position of the pointer. In the device for detecting the position of the pointer by detecting the change in the capacity, the hour hand and the minute hand constituting the pointer are respectively arranged on the pointer shafts having the same center of rotation, and the second hand is the hour hand and the minute hand. The pointer shaft is arranged on a second hand shaft arranged at a different position, and the electrodes on the dial are configured separately for the hour and minute hands and the second hand. Pointer position detection device.