JPS6115622B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display device suitable for application to a clock radio receiver.

For watches, especially radio receivers with electronic clocks, a radio receiver has been proposed that uses a display to display the time of the clock and also uses the display to display the receiving frequency when tuning. .

In this case, the time needs to be displayed on the display at all times, and the reception frequency only needs to be displayed temporarily when tuning. Therefore, when the oscillation signal from the local oscillator of the radio receiver is supplied to the frequency counter to detect the reception frequency and the reception frequency is supplied to the display, a switch is provided to switch from time display to reception frequency display. You can do this, but if you forget to switch from the received frequency display to the time display, the frequency display will remain, which is practically inconvenient.

In view of this, the present invention provides a display device in which a first display such as the time is normally displayed on the display, and when necessary, a second display such as the receiving frequency is displayed by operating an operation switch. is performed on this display,
After that, even if the switch is not operated, the display returns to the first display after a predetermined period of time, and when the electronic device such as a radio receiver is not in operation, the display returns to the first display in a shorter predetermined time than when it is in operation. The purpose of this paper is to propose a display device that is capable of moving back.

Embodiments of the present invention will be described in detail below with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIG. 1 is a first display signal generating means for generating a first display signal. In this example, this first display signal generating means is an electronic clock circuit. Therefore, the first display signal is a time signal. This electronic timepiece circuit 1 is a circuit that uses a crystal oscillator as a reference oscillator and divides the frequency of this oscillator to generate signals for hours, minutes, seconds, etc. In addition, year, month,
It may also be possible to generate signals such as the day of the week and the day of the week. + _B2 is the DC power supply for this clock circuit, and usually a small built-in battery is used.

2 is a second display signal generating means for generating a second display signal. In this example, the second display signal generating means is a frequency counter that counts the reception frequency of the radio receiver 8 as an electronic device. The radio receiver 8 is configured to be supplied with a DC power source + _B1 such as a built-in battery via a power switch 10 serving as a power switch circuit. Note that 9 is a speaker of the radio receiver 8. 4 is a display device.
This display 4 is a multi-digit display using a light emitting diode, liquid crystal, fluorescent display tube, etc., and each digit is
For example, numbers 0, 1, 2, . . . , up to 9, commas, etc. are displayed by selecting display elements arranged in a figure 8 pattern and causing them to emit light.
5 selects the first and second display signals and displays the display 4
This is a selection circuit that supplies That is, the time signal from the electronic clock circuit 1 and the received frequency signal from the frequency counter 2 are supplied to the selection circuit 5 and selected, and the selected one is supplied to the display 4 and displayed. be done.

6 is a control circuit that controls the selection circuit 5; 7
is a time constant circuit provided in this control circuit 6. SW ₁ is an operation switch that controls the control circuit 6.

This control circuit 6 will be explained below. DC power supply +B ₁ is PNP type switch transistor Q ₁
It is connected to the frequency counter 2 and the selection circuit 5 through the frequency counter 2 and the selection circuit 5. _Q2 is an NPN type control transistor for controlling the switching transistor _Q1 , and its cowactor is connected to the base of the transistor _Q1 , and its emitter is grounded.
The time constant circuit 7 is a variable time constant circuit, and the capacitor
It consists of C ₁ , C ₂ , resistors R ₁ , R ₂ and switching transistor Q ₃ . The DC power supply + _B1 is grounded through the operating switch _SW1 and further through the capacitor _C1 . The midpoint of the connection between the operating switch SW ₁ and the capacitor C ₁ is grounded through a series circuit with the capacitor C ₂ and the NPN type switching transistor Q ₃ . The voltage from the DC power supply + _B1 is applied to the resistive voltage divider via the power switch 10, and the divided voltage is supplied to the base of the transistor _Q3 . Also, the middle point of connection between operation switch SW ₁ and capacitor C ₁ is a resistor.
It is grounded through R ₁ and connected to the base of control transistor Q ₂ through resistor R ₂ . Capacitor C ₁ is selected to have a smaller capacitance than capacitor C ₂ .

Next, the operation of the display device shown in FIG. 1 will be explained. Under normal conditions, the time signal as the first display signal from the clock circuit 1 is selected by the selection circuit 5 and supplied to the display 4 to display the time as the first display. This is done regardless of whether the power switch 10 is on or off.

Further, when the radio receiver 8 is put into operation, the power switch 10 is turned on. At this time, transistor _Q3 is turned on and time constant circuit 7
The capacitance of is determined by the combined capacitance of capacitor _C1 and capacitor _C2 . Therefore, the time constant of the time constant circuit 7 is large. Operation switch SW ₁ is a non-lock normally open switch, and by turning it on temporarily, capacitors C ₁ and C ₂ are charged instantaneously, and the terminal voltage of capacitors C ₁ and C ₂ is immediately changed to DC power supply +B ₁
Therefore, the transistor Q ₂ is immediately turned on, and therefore the transistor Q ₁ is also immediately turned on, so that the DC voltage from the power supply +B ₁ is supplied to the frequency counter 2 and the selection circuit 5. For this purpose, an operating voltage is supplied to the frequency counter 2, which counts the received frequencies. In addition, when the selection circuit 5 is supplied with this DC voltage, it selects the received frequency signal from the frequency counter 2 and supplies it to the display 4. The reception frequency is thus displayed on the display 4. And the capacitor
The charges stored in C ₁ and C ₂ are gradually discharged through resistor R ₁ , resistor R ₂ and between the base and emitter of transistor Q ₂ , and when the base potential of transistor Q ₂ becomes 0.7V or less, the transistor Q ₂ is turned off, and therefore transistor Q ₁ is also turned off, and the operating voltage is no longer supplied to the frequency counter 2. Also, the selection circuit 5 selects the time signal from the electronic clock circuit 1 and supplies it to the display 4. I come to do it. In FIG. 2A, the operation switch SW ₁ is turned on at time t ₀ , and the selection state of the selection circuit 5 is maintained for r ₁ hour (for example, 30 seconds) so that the broken lap number signal from the frequency counter 2 is displayed on the display 4. Indicates that it is ready to be supplied.

Also, when the power switch 10 is off and the radio receiver 8 is in an inactive state, the operating switch SW ₁ is turned on in order to know which frequency (broadcasting station) will be received when the receiver is activated. When it is temporarily turned on, transistor Q ₃ is off, so capacitor C ₂ is essentially non-existent.
Therefore, the discharge time constant of the time constant circuit 7 is shorter than in the above case. That is, as shown in FIG. 2B, the frequency signal from the frequency counter 2 is supplied to the display 4 for τ ₂ hours (for example, 2 seconds), which is shorter than the above-mentioned time τ ₁ during which the frequency signal from the frequency counter 2 is supplied to the display 4. The signal is supplied to the display 4. Also, power switch 1
If the power switch 10 is turned off before τ ₁ hour has elapsed while Q 0 is on, the transistor Q ₃ will be turned off and the time constant of the time constant circuit 7 will be _shortened . Even before time elapses, as shown in FIG. 2C, the transistor _Q1 is turned off and no DC voltage is supplied to the frequency counter 2 and the selection circuit 5, and the display is immediately switched to the time display.

The reason for shortening the supply time of the DC voltage to the frequency counter 2 and the selection circuit 5 to τ ₂ when the power switch 10 is off and the radio receiver 8 as an electronic device is not operating is to shorten the supply time to τ 2. τ ₁
This is to avoid misidentification, since if it is made too long, the display 4 will display a received frequency display that may be mistaken for a time display.

In this case, it is conceivable to switch only the selection circuit 5 and constantly supply the operating voltage to the counter 2, but since the frequency counter 2 consumes a considerable amount of power, this is not possible if the DC power source is a built-in battery. Undesirable. Therefore, in the display device of the embodiment shown in FIG. 1, when the reception frequency is not displayed on the display 4, the supply of operating voltage to the counter 2 is also cut off.

According to the display device described above, in the normal state, the time is displayed on the display 4, and the operation switch SW ₁
The predetermined time τ ₁ (for example, 30 seconds)
The reception frequency will be displayed for the first time, and then the time will be displayed as usual.

In addition, when the radio receiver as an electronic device is not operating, the reception frequency is displayed on the display 4 for a short time, so the reception frequency that may be mistaken for the time cannot be displayed for a long time. There is no longer any possibility that the display may mislead the user.

Next, a second embodiment of the present invention will be described with reference to FIG. 3, in which parts corresponding to those in FIG. 1 are given the same reference numerals, and some redundant explanations will be omitted. In this embodiment, a timer circuit 3 controlled by a clock circuit 1
is provided as a third display signal generating means. Further, a power switch circuit 10 corresponding to the power switch 10 in FIG. 1 is composed of a PNP type switching transistor _Q4 , a PNP type transistor _Q5 for its control, and a manual switch _SW4 . . That is, the DC power supply + _B1 is connected to the radio receiver 8 through the transistor _Q4 . The emitter of transistor _Q5 is connected to the base of transistor _Q4 , and its collector is grounded. The output end of the timer circuit 3 is connected to the base of the transistor _Q5 through a resistor, and the output side of the timer circuit 3 is grounded through a manual switch _SW4 . Therefore, in this power switch circuit 10, when the manual switch SW ₄ is turned on or an output is obtained from the timer circuit 3, the base potential of the transistor Q ₅ is brought to approximately the ground potential. , the transistor _Q4 is turned on and the voltage from the power supply + _B1 is supplied to the radio receiver 8 as an operating voltage.
Incidentally, the timer circuit 3 is supplied with a DC voltage as an operating voltage from a DC power supply + _B2 similar to that shown in FIG. Further, a timer time signal from the timer circuit 3 is also supplied to the selection circuit 5. The first and third clock circuits 1 and 3 from this clock circuit 1 and timer circuit 3
In order to switch between _the time signal and timer time signal, which are _the display _signals of A time signal is supplied to the display 4, and when the timer circuit 3 is off, a timer time signal from the timer circuit 3 is supplied to the display 4.

The control circuit 6 includes a control circuit 6a for controlling the supply of operating voltage to the counter 2 and a control circuit 6b for supplying a control signal to the selection circuit 5. First, the control circuit 6a will be explained. Power supply +B ₁ is PNP type switching transistor Q ₁₅
It is connected to the frequency counter 2 through. _Q6 is a PNP type control transistor for controlling the switching transistor _Q15 , and its emitter is connected to the base of the transistor _Q15 , and its collector is grounded. The collector of the transistor Q ₄ , ie the input terminal of the operating voltage to the radio receiver 8, is connected in the forward direction through the diode D ₁ to the base of the transistor Q ₆ . The base of this transistor _Q6 passes through a diode _D2 in the forward direction and is further grounded through an operating switch _SW1 . This operating switch _SW1 is a non-lock normally open switch similar to that shown in FIG.

Next, the control circuit 6b will be explained. This control circuit 6b includes a time constant circuit (variable time constant circuit) 7 similar to the above-described embodiment. The DC voltage from the power supply + _B2 is supplied to the emitter of a PNP type switching transistor _Q7 . The collector is connected to the emitter of a PNP type control transistor _Q8 , and the collector of the transistor _Q8 is connected to the selection circuit 5, so that a selection control signal is supplied to the selection circuit 5. Furthermore, the output voltage of the collector of transistor _Q8 is divided by a resistive voltage divider and then supplied to the base of switching transistor _Q9 . The emitter of the transistor _Q9 is grounded, and its collector is connected to the midpoint between the diode _D2 and _the operation switch _SW1 (hereinafter referred to as point P) through the non-lock normally closed switch SW2. Note that the transistor _Q9 is configured to be turned on when the transistor _Q8 is turned on, and turned off when the transistor Q8 is turned off. In this example, the variable time constant circuit 7 is composed of a programmable union transistor (abbreviated as PUT) 12, a resistor _R1 ', capacitors _C1 and _C2 , and a switching transistor _Q3 . The voltage at the collector of transistor _Q7 is divided by a resistive voltage divider and supplied to the gate of PUT12. Further, the voltage from the collector of the transistor _Q7 is supplied to both ends of the series circuit of the resistor _R1 ' and the capacitor _C1 and the capacitor _C2 . and across capacitor C ₂
The collector and emitter of an NPN switching transistor _Q3 are connected. Further, the midpoint between the resistor R ₁ ' and the capacitor C ₁ is connected to the anode of the PUT 12 via the resistor, and its cathode is grounded. Further, the voltage at the collector of the transistor _Q4 of the power switch circuit 10 is divided by a resistive voltage divider and supplied to the base of the transistor _Q3 . Further, the base of transistor _Q6 is forwardly connected to the base _{of transistor Q7 through} diode D2.

Next, let us explain the operation of this display device. Let us first consider the state in which the transistor _Q4 of the power switch circuit 10 is on. Under normal conditions, clock circuit 1
The time signal, which is the first display signal, is selected by the selection circuit 5.
is selected and supplied to the display 4 to display the time as the first display. In this case, transistor Q ₆ is off, so transistor Q ₁₅ is off, and no operating voltage is supplied to counter 2.
Also, since the transistor Q ₇ is also off, the transistor Q ₈ is also off, and no DC voltage is supplied to the selection circuit 5. Therefore, the selection circuit 5
The display can be switched to display the time signal.

Next, when the operation switch SW ₁ is temporarily turned on, the transistor Q ₆ is turned on, and therefore the transistor Q ₁₅ is turned on, and the operating voltage is supplied to the counter 2. At the same time, transistor Q ₇ is turned on, which turns on transistor Q ₈ , which in turn turns on transistor Q ₉ , so that when switch SW ₂ is on, operating switch SW ₁ will be activated even if it is subsequently turned off. , P point remains at approximately ground potential. And the transistor
Since both Q ₇ and Q ₈ are on, the power supply +B ₂
This operating voltage is supplied to the time constant circuit 7 through the transistor _Q7 , and the capacitor _C1 is charged through the resistor R1 _' . In this case, transistor Q ₃ is on, so it is as if capacitor C ₂ were not present. Then, when the terminal voltage of capacitor C ₁ exceeds a predetermined voltage, PUT 12 is turned on and current flows from the anode to the gate, so transistor Q ₈ is turned off and transistor Q ₉ is also turned off, so that transistors Q ₁₅ and Q ₆ , _Q7
and _Q8 are all turned off. That is, as shown in FIG. 2A, the frequency signal from the frequency counter 2 is supplied to the display 4 for a predetermined time τ ₁ , and thereafter the time display signal is supplied to the display 4 again.

Next, transistor Q ₄ of the power switch circuit 10
Consider the case where is off. At this time, since the transistor Q ₃ is off, both the capacitors C ₁ and C ₂ of the time constant circuit 7 function. in this case,
For example, if capacitor C ₁ has a large capacity, capacitor C ₂
Assume that the capacity of is small. At this time, when the operation switch SW ₁ is temporarily turned on, the operating voltage is applied to the counter 2 in the same way as described above, and the frequency counter 2 is temporarily turned on by switching the selection circuit 5.
However, since the time constant of the time constant circuit 7 is small, the above-mentioned time τ ₁ is supplied to the display 4.
After a shorter time τ ₂ as shown in FIG. 2B, the time display is immediately switched to the time display. Further, when the transistor Q ₄ of the power switch circuit 10 is in the on state, a predetermined time τ determined by the time constant of the time constant circuit 7
If the transistor Q ₄ is turned off before the value reaches ₁ , the time constant of the time constant circuit 7 becomes smaller midway through, so the frequency display is quickly switched to the time display. If you want to quickly switch to the clock display when the frequency is displayed, press the switch.
This can be achieved by temporarily turning off SW ₂ (Figure 2C).

According to the above-described display device of the present invention, the first display is always displayed on the display, and when the display is temporarily switched to display the second display, the operation switch is only temporarily operated and the display is displayed after a predetermined time. This is convenient in practice because the display switches to the first display again, and when the electronic device is not operating, the display switches to the first display in a shorter predetermined time than when the electronic device is operating.

In particular, when the present invention is applied to a radio receiver with a clock, the time is displayed at all times, and only when necessary, that is, when tuning is performed, the time can be displayed in conjunction with the tuning knob, in conjunction with the tuning button, or not in conjunction with the tuning button. Simply operate the operation switch temporarily to display the frequency.
The time is automatically displayed after a predetermined period of time, which is extremely convenient in practice. Furthermore, the period during which the frequency signal serving as the second display signal from the frequency counter 2 serving as the second display signal generating means is supplied to the display 4 when the radio receiver as the electronic device is not operating is as described above. Since it is short, there is no possibility that the user will misunderstand the display of the receiving frequency, which is the second display. That is, for example, when a user wants to listen to a music broadcast, the radio receiver is activated and a channel selection operation is performed without specifying a broadcast station. At this time, the operation switch _SW1 is operated as described above. During the channel selection operation, attention is focused on the ears in order to hear the sound from the speakers. When a music broadcast is found, a normal user's action is to stop the channel selection operation and check the received frequency by looking at the display 4 in order to know which broadcast station has been received. . In this way, when selecting a channel, it is necessary to switch between listening to the sound with your ears and then looking at the frequency display with your eyes.
If the frequency display disappears immediately after the channel selection operation, there is a risk that the received frequency cannot be confirmed, and it is intuitively inconvenient.

Also, when the radio receiver is inactive,
If you want to know which frequency (broadcasting station) is being received after operation, and if you need to perform tuning operations, use this function if you are waiting for a specific program on a specific broadcasting station. Since the user is concentrating his or her attention on the display 4 before operating the operating switch SW ₁ , there is no need to make the frequency display time very long.

Furthermore, when a frequency counter is used as the second display signal generating means, it is only necessary to supply the operating voltage to the counter 2 only when making the second display, which is the received frequency, without constantly supplying the operating voltage to the counter 2. Therefore, the power consumption is small, and the present invention is particularly suitable for application to electronic devices such as radio receivers with a built-in battery.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention,
FIG. 2 is a waveform diagram, and FIG. 3 is a circuit diagram showing a second embodiment of the present invention. 1 is a first display signal generation means (electronic clock circuit), 2 is a second display signal generation means (frequency counter), 4 is a display, 5 is a selection circuit, 6 is a control circuit, 7 is a variable time constant circuit , SW ₁ is an operation switch (non-lock normally open switch), 8 is an electronic device (radio receiver), and 10 is a power switch circuit (power switch).

Claims (1)

[Scope of Claims] 1. A first display signal generating means for generating a first display signal, a second display signal generating means for generating a second display signal in relation to an electronic device, and a display device. ,
a selection circuit that selects the first and second display signals and supplies them to the display; a control circuit that controls the selection circuit; a variable time constant circuit provided in the control circuit; and an operation switch for controlling the electronic device, and in a normal state, the first display signal is supplied to the display through the selection circuit to perform the first display, and in the operating state of the electronic device, the first display signal is supplied to the display device through the selection circuit. When the operation switch is operated, the second display signal is supplied to the display through the selection circuit for a predetermined time determined by one of the time constants of the variable time constant circuit, and the second display is displayed. and when the operating switch is operated in the non-operating state of the electronic device, the second time constant is controlled for the other predetermined time determined by the other time constant smaller than the one time constant of the variable time constant circuit. A display device characterized in that a display signal of is supplied to the display device through the selection circuit to perform a second display.