JP3685454B2 - Auto correction clock for in-vehicle use - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic timepiece that adjusts time by receiving a time signal by radio waves, for example. More specifically, the present invention relates to an on-vehicle automatic correction timepiece that is mounted on a vehicle such as an automobile and displays time by a fluorescent display tube.
[0002]
[Prior art]
In a vehicle such as an automobile, for example, an in-vehicle automatic timepiece that receives a long standard wave (JJY) that conveys Japan Standard Time (JST) with high accuracy and corrects the display time based on the received signal has been proposed.
Such an automatic correction watch incorporates a reception system circuit that receives a standard radio wave and a control system circuit that corrects the time to be displayed to a time based on the received standard radio wave. The standard time signal is received in a predetermined time zone such as midnight, and the time is corrected.
[0003]
In an in-vehicle self-correcting timepiece, there is a possibility that stable reception cannot be performed while the vehicle is running, for example, because the engine noise or the movement of the vehicle prevents radio waves from reaching. For this reason, in an on-vehicle automatic correction watch, for example, an engine and a vehicle are used by utilizing the state of the vehicle such as on / off of an engine start switch and on-vehicle electrical equipment such as a car stereo, and vehicle speed. Reception is performed when it is detected that the operation is stopped. In the following, an electrical device such as a car stereo or a power window that moves using electric power from a vehicle battery is referred to as an accessory.
As an in-vehicle automatic correction timepiece that receives and detects an engine stop when an accessory switch that supplies power to an accessory is turned off, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-14183. .
[0004]
[Problems to be solved by the invention]
However, when the state of the accessory switch or the start switch is used, the switch is actually turned to be turned off or turned on, so that the detection signal in the on / off state is likely to chatter. If this detection signal is input to the control circuit for time correction as it is, there is a possibility that a malfunction occurs in which the mode is shifted to a mode in which radio waves are not received or is forcibly received due to chattering.
[0005]
Similarly, when using the running state of the vehicle such as the vehicle speed, the control circuit malfunctions due to subtle changes during the transition from the running state to the stopped state, or vice versa, or due to causes such as running or engine vibration. there is a possibility.
In order to prevent these malfunctions, it is necessary to provide additional parts such as a chattering prevention circuit, which leads to an increase in manufacturing cost.
[0006]
The present invention has been made in view of these problems, and provides an in-vehicle automatic correction timepiece capable of performing a stable time adjustment operation at a low cost without causing a malfunction due to, for example, switch chattering. Objective.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object of the present invention, an on-vehicle automatic correction timepiece that is mounted on a vehicle according to the present invention and receives a time signal to automatically correct a display time receives the time signal. A receiving means; a grid electrode that is energized or de-energized according to the startup state of the vehicle; a fluorescent display tube that displays time when the grid electrode is energized; and the grid electrode is energized Detecting means for detecting whether it is in a state or in a non-energized state, and when the detecting means detects that the grid electrode is in a non-energized state, the receiving means receives a time signal, and the fluorescent display Control means for correcting the time to be displayed on the tube to a time based on the received time signal.
[0008]
In the present invention, the control means generates time data to be displayed on the fluorescent display tube based on the time signal received by the receiving means.
The grid electrode of the fluorescent display tube is in an energized state or a non-energized state depending on the start state of the vehicle such as whether the engine of the vehicle is started or stopped. When the grid electrode is in the energized state, the fluorescent display tube is lit and displays the time represented by the time data generated by the control means. When the grid electrode is not energized, the fluorescent display tube is turned off.
The detection means detects whether the grid electrode is in an energized state or a non-energized state, and transmits information on display or extinguishing of the fluorescent display tube to the control means.
Based on the information from the detection means, the control means causes the reception means to receive a time signal when the grid electrode is in a non-energized state, and corrects the time data.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In the following description, a radio-controlled timepiece that is mounted on an automobile and receives a standard radio wave and corrects the time will be described as an example of an automatic correction timepiece.
FIG. 1 is a schematic configuration diagram of an embodiment of an in-vehicle radio wave correction watch according to the present invention.
[0010]
The on-vehicle radio-controlled timepiece 1 shown in FIG. 1 includes a receiving antenna 11a, a receiving circuit 11b, a control circuit 14, a fluorescent display tube 15, and a detection circuit 16.
1 represents a battery terminal of a vehicle as a power source, and LIG and ILL represent a light switch of the vehicle and a dimming switch terminal of a lighting display device. Symbols ACC and IGN represent electrical equipment such as car stereos and power windows, that is, terminals for power supply switches to in-vehicle accessories and automobile start switch terminals, respectively, and GND represents an automobile ground terminal. Represents.
[0011]
The receiving antenna 11a receives a long standard wave including a time code transmitted from a transmitting station.
The long wave receiving circuit 11b performs predetermined signal processing on the standard radio wave received by the receiving antenna 11a in response to a command from the control circuit 14, and outputs it to the control circuit 14 as a pulse signal PL. The receiving circuit 11b includes, for example, an RF amplifier, a radio wave detection circuit, a rectifier circuit, and an integration circuit.
The receiving means in this invention is comprised using the receiving antenna 11a and the receiving circuit 11b.
[0012]
The control circuit 14 corresponds to an embodiment of the control means in the present invention.
The control circuit 14 decodes the pulse signal PL from the receiving circuit 11b and obtains the standard time. Further, the control circuit 14 includes an internal clock (not shown) using a basic clock of a predetermined frequency supplied from the oscillation circuit 13, and the time from the obtained standard time is counted by this internal clock, and a fluorescent display to be described later. Time data to be displayed on the tube 15 is generated and sent to the fluorescent display tube driver 22.
The fluorescent display tube driver 22 displays the time indicated by the time data on the fluorescent display tube 15.
[0013]
The on-vehicle radio-controlled timepiece 1 displays the time by the fluorescent display tube 15.
The fluorescent display tube 15 has a grid electrode (grid) 18 and a cathode (filament) 20, and the electrons emitted from the filament 20 in the vacuum vessel are accelerated and controlled by the grid 18 and applied in the form of numbers and letters. The time is displayed digitally by colliding with the fluorescent screen.
The emission of electrons from the filament 20 and the acceleration of electrons by the grid 18 are controlled by the fluorescent display tube driver 22.
[0014]
A current of a predetermined voltage is supplied from the battery terminal BAT to the grid 18 of the fluorescent display tube 15.
The detection circuit 16 uses a voltage drop generated across the current detection resistor 24 provided between the battery terminal BAT and the grid 18 to determine whether the grid 18 is in an energized state or a non-energized state. That is, it is detected whether or not the fluorescent display tube 15 is displayed.
[0015]
Specifically, the detection circuit 16 is configured as follows, for example. Using the transistors Tr1 and Tr2, the base of the transistor Tr1 is connected to the grid 18 and one end of the current detection resistor 24, the emitter is connected to the other end of the current detection resistor 24, and the collector is connected to the base of the transistor Tr2. The emitter of the transistor Tr2 is grounded, and the collector is connected to the battery terminal BAT via the resistance element R.
[0016]
When the fluorescent display tube 15 is turned on, the grid current flows by several tens of mA and the energized state occurs, and a voltage drop of about 0.7 V occurs as an example at both ends of the current detection resistor 24. As a result, the transistor Tr1 is turned on, and the transistor Tr2 is also turned on due to a potential difference generated between the base and collector of the transistor Tr2. A low-level detection signal DT is input to the control circuit 14 from the collector of the transistor Tr2.
When the fluorescent display tube 15 is turned off, the grid current does not flow and the current detection resistor 24 is not energized, and no voltage drop occurs across the current detection resistor 24. Accordingly, the transistor Tr1 is turned off, the transistor Tr2 is also turned off, and a high level detection signal DT of about 5 V, for example, is input to the control circuit 14.
The detection circuit 16 corresponds to an embodiment of the detection means in the present invention.
[0017]
The filament 20 of the fluorescent display tube 15 is connected to the accessory terminal ACC and the start switch terminal IGN. In the present embodiment, when the car key is turned and the accessory switch is turned on, power is supplied to the accessories including the fluorescent display tube 15, and the engine is started when the key is further turned and the start switch is turned on. It shall be. The fluorescent display tube 15 is lit and displays the time when the switch to the filament 20 is turned on regardless of whether the accessory switch is on or the start switch is on.
On the contrary, the fluorescent display tube 15 is not turned off but remains lit only when the start switch is turned off and the engine is stopped. When the accessory switch is turned off after the engine is stopped, the fluorescent display tube 15 is also turned off. It becomes a state and turns off.
[0018]
Further, the accessory terminal ACC and the start switch terminal IGN are also connected to the control circuit 14 via the surge protection circuit 26c.
The control circuit 14 is further connected to a battery terminal BAT via a surge protection circuit 26a, and is supplied with power.
The light switch terminal LIG and the dimming switch terminal ILL are also connected to the control circuit 14 via the surge protection circuit 26b. When the light switch is turned on and the automobile light is turned on, the control circuit 14 performs a dimming operation to reduce the display luminance by lowering the supply voltage to the lighting display device including the fluorescent display tube 15. When the dimming switch is turned on, the control circuit 14 dims the lit display device even when the light is not lit.
[0019]
By the way, the oscillation circuit 13 that transmits the basic clock to the control circuit 14 includes, for example, a crystal resonator CRY and capacitors C ₁ and C ₂ .
The crystal resonator CRY installed in the automobile is subjected to a temperature change of about several tens of degrees Celsius, whereby the frequency of the crystal resonator CRY changes, and the time indicated by the internal clock in the control circuit 14 is accurate from the time. It will shift. Therefore, it is necessary to obtain an accurate standard time and correct the time of the internal clock.
[0020]
Hereinafter, a method for obtaining the standard time using the standard radio wave will be described with reference to FIGS.
A long-wave standard radio wave JJY that conveys Japan Standard Time with high accuracy is sent in the form shown in Fig. 2 (a).
Specifically, the time code of JJY is composed of three types of signal patterns: “1” signal, “0” signal, and “P” signal, each signal pattern having 100% amplitude in 1 second (s) Differentiated by period width. That is, when a “1” signal is represented, a signal having a predetermined frequency is transmitted for 500 ms (0.5 s) during one second (s), and when a “0” signal is represented, one second (s). A signal having a predetermined frequency is transmitted for 800 ms (0.8 s) in the meantime, and a signal having a predetermined frequency is transmitted for 200 ms (0.2 s) during one second (s) when the “P” signal is represented. Come.
When the reception state is good and reception is successful, a pulse signal PL corresponding to the waveform of the standard radio wave is output from the reception circuit 11b to the control circuit 14, as shown in FIG.
In this case, the control circuit 14 considers that the received state of the received standard radio wave is within a normal reference range defined in advance.
[0021]
On the other hand, when the reception state is considered to be out of the reference range, the radio wave is weak or there is a lot of noise.
When the radio wave is very weak, as shown in FIG. 2C, the pulse signal PL remains at a low level (L) or a high level (H) for several signals.
When there is a lot of noise, the level of the pulse signal changes regardless of the waveform of the radio wave, as shown in FIG.
When the pulse signal PL in these states is received, for example, twice in 10 seconds or more, the control circuit 14 considers that the reception state is out of the reference range and the reception is not successful.
Specifically, for example, when the detection time is about 10 seconds, the level change of the pulse signal PL is not detected for 1 second within this detection time, and the detected pulse width is 0.8, 0.5, If it is not in the vicinity of 0.2 s, NG is assumed, and when NG occurs more than once, it is considered that reception is impossible.
[0022]
Japan's standard radio wave JJY is operated by the Communications Research Laboratory (CRL) as of April 30, 2002. As a standard radio frequency, a frequency of 40 kHz has been used so far, but since October 1, 2001, a transmitting station that transmits a standard radio wave of 60 kHz has been opened.
The amplitude of the pulse signal PL, which is a modulated wave, is 100% at maximum and 10% at minimum.
[0023]
Next, transmission data of the long wave standard radio wave will be described.
FIG. 3 is an example of a time code of a standard radio signal.
As shown in FIG. 3, the time code is divided into 60 periods of one minute and one period (one frame), and 1-bit information is assigned and transmitted every second.
[0024]
The information sent by the time code is the hour, minute, day of the month since January 1, year (last two digits of the year), day of the week, leap second information, parity corresponding to the hour and minute, spare bits, and stop notice information. Yes, the hour, minute, the day since January 1, the year (last 2 digits), and the day of the week are expressed as binary numbers (BCD (Binary Coded Decimal Notation) positive logic) and transmitted. To do. Therefore, sometimes it takes 6 bits to represent the time of the 24-hour JST, 7 bits for the minutes, 10 bits for the day of the week, 8 bits for the year, and 3 bits for the day of the week.
As for the second signal, the second is the rising edge of the radio wave pulse signal, and the 55% value (the center of the 10% value and the 100% value) of the rising edge of the pulse is synchronized with the standard time 1 second signal.
[0025]
The P signal is transmitted 7 times per frame, and the one corresponding to the minute (0 seconds) is called marker M, and the one corresponding to 9 seconds, 19 seconds, 29 seconds, 39 seconds, and 49 seconds is the position marker. Called P1-P5.
The other position marker P0 normally corresponds to a rise of 59 seconds (in the case of non-leap seconds). The P signal continues to appear only once in one frame at 59 seconds and 0 seconds, that is, when it continues with the position markers P0 and M, and the position where it continues appears as the minute position. That is, the time data such as the minute / hour data is determined in the frame with reference to the minute position, and the time data cannot be extracted unless the minute position is accurately detected.
[0026]
However, the format of the standard radio wave frame is not the same every minute, and as shown in FIG. 3, the format of the hour at 15 minutes and 45 minutes and the format of the other minutes are different. The spare bits and leap second information are included only in formats other than 15 minutes and 45 minutes shown in FIG. 3A, and as shown in FIG. 3B, the call code and the stop information are year information and day information. Appears only in 15-minute and 45-minute formats.
[0027]
In this way, the standard time can be obtained by receiving the standard radio wave including the time code and decoding the pulse signal PL obtained therefrom.
[0028]
However, when the radio wave reception state is poor, it is not possible to obtain an accurate standard time.
Due to the relationship between the directivity of the receiving antenna 11a and the moving direction of the vehicle, the strength of radio waves depending on the location where the vehicle is moving, and noise from the engine, the success probability of reception while the vehicle is running is stopped. Is considered to be lower. Therefore, as described above, it is conceivable to detect that the automobile is stopped, enter the forced reception mode when the stop is detected, and receive radio waves while the vehicle is stopped.
However, if it is detected from the accessory terminal ACC and the start switch terminal IGN that the accessory switch and the start switch are turned on or off, the control circuit 14 may malfunction due to the switch chattering as described above. .
[0029]
In the present embodiment, as described above, the detection circuit 16 detects whether the grid 18 of the fluorescent display tube 15 is in an energized state or in a non-energized state, thereby turning on / off the accessory switch and the engine. Determine the start state of the car, such as start or stop.
Hereinafter, the time correction control operation according to the start state of the vehicle in the present embodiment will be described with reference to FIG.
[0030]
FIG. 4 is a flowchart of one embodiment of the time correction control operation according to this embodiment. Hereinafter, unless otherwise specified, the control circuit 14 performs determination and processing during the time adjustment control operation.
The time adjustment control operation is started, for example, when the control circuit 14 is connected to the battery terminal BAT and the initial time is manually input, for example.
[0031]
When the time correction control operation is started, it is first determined whether or not it is a time for receiving radio waves (step ST1).
The regular reception is reception of radio waves at a predetermined time regardless of the activation state of the automobile. For example, the reception operation is performed at a predetermined set time such as 24:00 or 6 o'clock.
If it is not the scheduled reception time, the process proceeds to step ST2, and if it is the reception time, the process proceeds to step ST5, and the scheduled time correction operation is started.
[0032]
If it is not the scheduled reception time, next, based on the input from the detection circuit 16, whether the grid 18 is in the non-energized state or the energized state, that is, whether the fluorescent display tube 15 is turned off. Is determined (step ST2).
When the low level detection signal DT is input from the detection circuit 16, the control circuit 14 determines that the display of the fluorescent display tube 15 is not turned off. In this case, the engine is not stopped and noise is likely to be mixed in the radio wave, or the accessory switch is on even when the engine is stopped, and the engine may start. Thus, the time correction operation is not performed, and the process returns to the standby state of step ST1 for determining the scheduled reception time.
When the high-level detection signal DT is input from the detection circuit 16, the display of the fluorescent display tube 15 is turned off, and not only the engine but also the accessory switch is in the off state, and the automobile is completely stopped. The process proceeds to step ST3.
[0033]
If it is determined that the display of the fluorescent display tube 15 is turned off and the automobile is stopped, for example, within 24 hours from that point of time, reception including normal reception and forced reception succeeds normally, and the time adjustment operation is performed. It is determined whether it has been performed (step ST3).
If reception has been successful, no further time adjustment operation at the present time is required, and the process proceeds to step ST4.
If the reception is not successful and the time has not been corrected, the forced reception operation in step 5 and subsequent steps is entered.
If it is desired to perform the time adjustment operation more frequently, the determination reference time in step ST3 may be shortened.
If there is no need for forced reception in step ST3, the control circuit 14 performs a time-keeping process that continues to transmit time data from the internal clock to the fluorescent display tube driver 22 (step ST4), and returns to the standby state of step ST1. .
[0034]
If the forced reception mode is entered according to the determination in step ST3, the control circuit 14 transmits a command signal CMD to the reception circuit 11b to start reception of radio waves (step ST5).
Although the time code of the standard radio wave is one frame per minute, there may be a case where a complete time code cannot be obtained due to radio wave conditions or noise from the surroundings. Further, as described above, the data format varies depending on the time. Therefore, the radio wave reception time is set to 10 minutes, for example, and the radio wave is continuously received during the reception time. It is determined whether or not the reception time has ended with the internal clock (step ST6), and the timing process is performed within the reception time (step ST7). When the reception time ends and the reception is completed, the process proceeds to step ST8.
[0035]
When reception is completed, the control circuit 14 decodes the pulse signal PL from the reception circuit 11b and determines whether a complete time code is obtained (step ST8).
If reception has not been successful and a complete time code has not been obtained, the time obtained by reception is not used, time measurement processing is performed according to the time of the internal clock, and the process returns to the standby state of step ST1 (step ST9). ).
[0036]
If it is determined in step ST8 that a complete time code has been obtained and reception has been successful, time adjustment processing is performed to correct the time of the internal clock to a new time obtained by reception (step ST10).
When the time adjustment process in step ST10 is completed, the process returns to the standby state in step ST1, and the control circuit 14 continues to determine whether it is a scheduled reception time.
The exit from the loop of steps ST1 to ST10 is, for example, when the battery is removed from the automobile and the power supply to the control circuit 14 is cut off.
[0037]
Steps ST5 to ST10 are common to the normal reception mode at regular time and the forced reception mode when the fluorescent display tube 15 is turned off, and the time of the internal clock of the control circuit 14 is corrected.
If a new reception time is obtained when the fluorescent display tube 15 is turned on, the control circuit 14 causes the fluorescent display tube 15 to display a time based on the corrected time of the internal clock.
When the time is corrected by forced reception when the fluorescent display tube 15 is turned off or normal reception while the fluorescent display tube 15 is turned off, the control circuit 14 next time the fluorescent display tube 15 is turned on. The time based on the corrected internal clock is displayed on the fluorescent display tube 15.
[0038]
Thus, according to the present embodiment, forced reception is performed when the accessory switch is turned off, the grid 18 is turned off, and the fluorescent display tube 15 is turned off. Therefore, there is a higher possibility of avoiding noise from restarting the engine or driving, compared to the case where the accessory switch remains on and the engine is stopped or the vehicle speed is detected when the start switch is turned off.
Further, since the on / off state of the accessory switch and the start switch is not directly detected, but the state of the current flowing through the grid 18 of the fluorescent display tube 15 is detected, it is stable without being affected by chattering due to the operation of the switch. Thus, it is possible to shift to the time correction control operation. Further, there is no need to provide additional parts such as a chattering prevention circuit, and an increase in the cost of the radio-controlled timepiece can be suppressed.
[0039]
The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the claims. For example, the configuration of the detection circuit 16 may be appropriately configured so that the grid current can be detected.
Further, in the above-described embodiment, the reception operation is started as soon as the fluorescent display tube 15 is turned off. For example, reception and time correction may be performed after a predetermined time has passed since the turn-off.
Furthermore, instead of directly receiving the standard radio wave JJY, the standard time may be obtained from a time transmitter such as a booster provided in the garage.
[0040]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an in-vehicle automatic correction timepiece that can perform a stable time adjustment operation at low cost without causing malfunction due to, for example, switch chattering.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment of an in-vehicle radio wave correction timepiece according to the present invention.
FIG. 2 is a diagram illustrating a signal pattern of a standard radio wave.
FIG. 3 is a diagram illustrating an example of a time code of a standard radio wave.
FIG. 4 is a flowchart of an example of a time correction control operation according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Car radio correction clock 11a ... Reception antenna 11b ... Reception circuit 13 ... Oscillation circuit 14 ... Control circuit 15 ... Fluorescent display tube 16 ... Detection circuit 18 ... Grid (grid electrode)
20 ... Filament (cathode)
22 ... Fluorescent display tube driver 24 ... Current detection resistor
Tr1, Tr2 ... Transistor

Claims (2)

An on-vehicle automatic correction clock that is mounted on a vehicle and receives a time signal to automatically correct the display time,
Receiving means for receiving a time signal;
A fluorescent display tube that includes a grid electrode that is energized or de-energized according to the startup state of the vehicle, and displays time when the grid electrode is in an energized state;
Detecting means for detecting whether the grid electrode is energized or not energized;
When the detecting means detects that the grid electrode is in a non-energized state, the receiving means receives the time signal, and the time to be displayed on the fluorescent display tube is corrected to the time based on the received time signal. A vehicle-mounted automatic correction timepiece having control means for performing the operation. 2. The on-vehicle automatic correction timepiece according to claim 1, wherein the grid electrode is in a non-energized state when the vehicle is not activated and an electrical system to electrical equipment of the vehicle is also in an off state.

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