JPS632176B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radio receiver with an electronic digital clock, and more particularly to a device for automatically switching the brightness of the display device between bright brightness and dark brightness.

In general, a radio receiver with a digital clock has the functions of a clock and a radio receiver, and when the user goes to bed, the user turns on the radio and listens to it, and after a certain period of time, the user turns on the radio and listens to it. You can set a so-called sleep mode in which the radio automatically turns off, and a so-called alarm mode in which you can set a wake-up time and the radio starts to chirp at that time.

By the way, when a user goes to bed, if the time or other display on the display device is too bright, it will disturb sleep, so it is necessary to switch to a dark brightness. Conventionally, the user has to operate a mechanical manual switch. It was designed to switch between bright brightness and dark brightness.

FIG. 1 shows a conventional example. Reference numeral 1 denotes a clock section composed of an LSI, and 2 a display section equipped with a display tube, which displays the time and the like in accordance with display data from the clock section 1. S ₁ is a switch for setting an alarm, and if you set the alarm operation time and connect it to the ON side, and connect switch S ₂ to the radio side, the alarm will be sent from the clock section 1 at the set time.
A system signal is output, which turns on the radio and makes it start playing.

Switching between bright brightness and dark brightness in the display section 2 is performed by a mechanical switch _S3 . That is, the switch
When S ₃ is connected to the a side, the voltage of all windings of power transformer T is rectified by diode D ₁ and capacitor C ₁ ,
It is smoothed and supplied to the grid and plate of the display tube of the display section 2 via the clock section 1. At this time, the brightness becomes bright. On the other hand, when the switch _S3 is connected to the b side, the voltage from the intermediate terminal of the transformer winding is supplied to the display tube as half-wave rectification, resulting in dark brightness. Note that _S4 is an external switch for supplying power to low frequency parts such as radio and chirp.

As described above, in the conventional example, the user had to manually operate the switch _S3 to switch between bright brightness and dark brightness as necessary.

In the present invention, when an alarm is being set and a sleep operation overlaps, the display automatically becomes dim regardless of the connection of the brightness changeover switch, and the user can switch the external switch when the alarm operation is started or during the alarm operation. To provide a radio receiver with a digital clock which returns to the original connection state of a changeover switch when the radio section power is turned on. Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 2 shows one embodiment of the present invention.
The same reference numerals as in FIG. 1 indicate the same elements, and 3 is an AND circuit for an alarm setting signal and a sleep output, and 4 is an R-S flip-flop circuit. Transistors Tr ₁ and Tr ₂ and transistors Tr ₃ and Tr ₄ each constitute a switching circuit, and when the output Q of the flip-flop circuit 4 is low level and is high level, transistors Tr ₁ and Tr ₂ are turned on. become a transistor
Tr ₃ and Tr ₄ are turned off. Conversely, when Q is high level and Q is low level, the transistor
Tr ₁ and Tr ₂ are turned off, and transistors Tr ₃ and Tr ₄ are turned off.
is turned on.

First, switch _S1 is turned to the OFF side, and in the normal state where no alarm is set, both sleep output A and alarm setting signal B are at low level, and there is no alarm output, so the input S of flip-flop circuit 4, Both R are at low level, therefore,
Output Q goes from low level to high level, transistors Tr ₁ and Tr ₂ turn on, Tr ₃ and Tr ₄ turn off, and the brightness state follows the connection of switch S ₃ (that is, if connected to a Bright brightness, if connected to b, dark brightness).

Next, when switch _S5 is operated from this state to enter sleep operation, sleep operation signal A is output from clock section 1, and this output A is connected to a diode.
Turn on the radio after going through D ₅ and the radio will start playing. However, even if the sleep output is obtained, the alarm setting signal is not input, so the flip-flop circuit 4
The output Q of remains low level, and the brightness status still follows the connection status of switch _S3 .

Here, if switch _S1 is connected to the ON side and an alarm is set, and the sleep operations overlap, signals A and B become high level, and therefore output C of AND circuit 3 becomes high level. . Therefore, the set input S of the flip-flop circuit 4 becomes high level, so the output Q becomes high level and becomes low level, transistors Tr ₁ and Tr ₂ are turned off, and Tr ₃ and Tr ₄ are turned on, and the brightness state is changed to a switch. Regardless of _S3 , the brightness is dark.

Next, at the alarm setting time, an alarm operation signal is output from the clock section 1, the radio is turned on, and the flip-flop circuit 4 is turned on.
Since the reset input R becomes high level, the output Q
becomes low level, becomes high level, transistors Tr ₁ and Tr ₂ are turned on, Tr ₃ and Tr ₄ are turned off, and the brightness state follows the state of switch S ₃ . In other words, it has returned to its original state.

Furthermore, when the sleep operation overlaps with the alarm setting and the display section 2 is dimly lit, when the user closes the external switch _S4 and connects the power to the radio section, the reset input R of the flip-flop circuit 4 becomes high level. , the brightness state will follow the connection of switch _S3 , ie, return to the original state, similar to when the alarm is activated. Furthermore, if the manual switch _S6 is left open, even if the alarm goes into sleep mode while the alarm is being set, the set input to the flip-flop circuit 4 will be cut off, so the brightness will remain the same as that of the switch _S3 .
It is natural to follow the connection.

Figure 3 shows how the brightness of the display section is switched by appropriately combining sleep operation and alarm settings. This is the dark brightness time due to switching. In this case, switch S ₃ in Figure 2
is connected to side a. Alarm setting in progress (signal B
When a sleep operation (signal A is at a high level) and a sleep operation (signal A is at a high level) overlap, the output Q (signal F) of the flip-flop circuit becomes a high level and the output (signal E) becomes a low level, and the brightness is switched to dark. In this state, the dark brightness is maintained until the high level signal D is input to the reset input R of the flip-flop circuit, but when it is input, the output Q (signal F) goes to low level and (signal E) goes to high level, and the brightness changes. Can be switched to brightness.

As explained above, according to the present invention, when going to bed, the display section automatically dims and does not disturb sleep, and when you wake up, it automatically returns to brightness, which is different from conventional methods. This eliminates the hassle of operating a manual switch each time as in the example above, making it extremely convenient.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a conventional example, FIG. 2 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG.
The figure is an explanatory diagram of the operation of FIG. 2. 1... Clock section, 2... Display section, 3... AND circuit, 4... R-S flip-flop circuit, S ₁
……Alarm setting switch, S ₃ ……Manual switch for bright/dark brightness switching, S ₄ ……Radio unit power switch, S ₆ ……Manual switch for stopping automatic switching operation,
Tr ₁ , Tr ₂ , Tr ₃ , Tr ₄ ...transistor.

Claims (1)

[Claims] 1 A first manual switch that switches the display between bright brightness and dark brightness, and when a sleep operation overlaps with an alarm setting, sets the display to dark brightness regardless of the connection of the first manual switch and activates the alarm. an automatic brightness switching means that returns to the connected state of the first manual switch when the radio unit is turned on by an external switch, and a second manual switch that stops the operation of the automatic brightness switching means. A radio receiver with a digital clock, characterized by comprising: