JPS5819995B2 - car clock - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an automobile timepiece, and particularly to an electronic digital timepiece for an automobile that consumes less battery.

2. Description of the Related Art Electronic digital clocks that digitally display the time using light emitting diodes and other light emitting elements are used as automobile clocks.

This digital automobile watch has the advantage of being easy to read the time while driving, but has the disadvantage of high battery consumption.

As is well known, in an electronic digital watch, most of the current consumption is consumed by the display section, and the amount consumed by other circuits is extremely small.

Digital clocks for automobiles that utilize this fact and have low current consumption have been proposed in the past.

According to this conventional device, it is possible to obtain a structure in which the drive power to the display section is cut off when the automobile is not in operation, thereby reducing battery consumption.

Therefore, unnecessary battery consumption for driving the front thread part when the occupant is away from the car can be prevented, and since the clock's timekeeping part itself continues to operate, the time will be displayed immediately when the car is started. was able to exhibit good characteristics in that it revived.

However, it has become clear that this conventional device cannot display the time at all when the vehicle is not in operation, causing inconvenience in actual use, and an improvement has been desired.

In other words, it has become clear from experience that there is a relatively high need for vehicle occupants to know the time while the engine is stopped and the vehicle is parked.

When such a request occurs, the conventional device has to start the engine simply to display the time, which is extremely inconvenient.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide an improved electronic digital timepiece for automobiles that consumes less battery.

In order to achieve the above object, the present invention includes an engine operation detector and a brightness switching circuit, and when the engine is not in operation, the time display brightness is lowered so that the time can be displayed, but the battery consumption is extremely low. An electronic digital watch for automobiles having these characteristics was obtained.

Preferred embodiments of the present invention will be described below based on the drawings.

A first embodiment of the present invention is shown in FIG. 1, and the electronic digital watch body is composed of a timekeeping section 10 and a display section 11.
Since its detailed structure is well known, illustration thereof will be omitted.

As an example of the timekeeping section 10, a configuration including a reference signal generator such as a crystal oscillator, a frequency divider, a counting circuit, and a display signal generator is known. A configuration including the element is known.

The clock section 10 is activated by a drive voltage supplied from the battery 12, and its display signal 100 is displayed on the display section 11.

The battery 12 is connected to the display section 11 via a brightness switching circuit 13.

The brightness switching circuit 13 consists of two resistors 14.1 connected in series.
5 and a bypass switch 16 connected in parallel to a resistor 14.

Therefore, whether the voltage of the battery 12 is supplied to the display section 11 through the resistors 14 and 15 or through the bypass switch 16 and the resistor 15 is controlled.

On/off control of the bypass switch 16 is performed by an engine operation detector 17, and in this first embodiment, the engine operation detector 17 is formed by an engine key switch.

The first embodiment of the present invention has the above configuration, and its operation will be explained next.

First, when the engine is running, the engine key switch 17 is turned on, and accordingly, the bypass switch 16 is also turned on.

Therefore, the resistor 14 is short-circuited by the bypass switch 16, and sufficient current is supplied to the display section 11 for high-brightness display.

The reason why the time is displayed with high brightness when the engine is running is because when the engine is running, especially when the vehicle is running, it is difficult to check the time displayed on the display unit 11 due to vibrations of the vehicle. This is because the time required to look at the display section 11 while driving is extremely short, so if the time is displayed at low brightness, the functions of the display section 11 cannot be fully demonstrated.

Next, when the engine is not operating, the engine key switch 17 is turned off and the bypass switch 16 is also turned off at the same time.

As a result, the current supplied from the battery 12 to the display section 11 is reduced by the resistor 14, and the display section 11 is switched to low brightness display.

As is clear from the above description, when the engine is put into a non-operating state in the illustrated embodiment, the current supplied from the battery 12 to the display section 11 is automatically reduced to reduce battery consumption. 11 is maintained with a small current supply, so that the time display can be read by a passenger in a non-operating state.

FIG. 2 shows a second embodiment of the present invention, in which the same components as in the first embodiment are given the same reference numerals and their explanation will be omitted.

The characteristic feature of the second embodiment is that the brightness switching circuit 13 controls the display signal 100.

A display signal 100 from the clock section 10 is sent to the display section 11 via the AND gate 21 of the brightness switching circuit 13.

A duty signal generator 2 is connected to the other terminal of the AND gate 21.
The output of No. 2 is printed, and the opening and closing of the gate 21 is controlled.

The duty signal generator 22 has its output as shown in FIGS. 3a and 3b.
Two types of pulse signals shown by are output, and switching between them is performed by the engine key switch 17.

The operation of the second embodiment will be explained.

When the engine is operating, the duty signal generator 22 applies the pulse signal shown in FIG. 3a to the AND gate 21, so that the display signal 100 is sent almost unchanged to the display section 11, resulting in a high-brightness display.

The pulse frequency at this time is set to 50H2 or more, so that it does not adversely affect the display effect.

Next, when the engine is not operating, the duty signal generator 22 applies a pulse (No. 8) with a small pulse width as shown in FIG.

Although the duty signal generator 22 is shown as having its own signal generation source in FIG. 2, the clock section 1
It is also possible to use a zero reference signal.

In the second embodiment, it is also possible to apply the output of the duty signal generator 22 to the AND gate 21 as a continuous constant voltage DC signal with a duty of 100%, that is, as shown in FIG.

FIG. 4 shows a third embodiment of the present invention, and the same components as in the other embodiments are given the same reference numerals and their explanations will be omitted.

The characteristic feature of the third embodiment is that the engine operation detector 17 is formed of a current sensing element that detects the rotation of the engine 31, and the rotation of the engine 31 is converted into an electric current which is measured by the tachometer 32. It is suitable for automobiles that

Either the current sensing element 17 or the bypass switch 16 is held in the ON state while the engine 31 is rotating and supplying current, or the current sensing element 17 turns off the bypass switch 16 when the engine 31 is stopped.

The function of the brightness switching circuit 13 is similar to that in the first embodiment.

FIG. 5 shows a fourth embodiment of the present invention, in which the duty signal generator 22 and the AND gate 21 in the second embodiment are shown.
The brightness switching circuit 13 is a combination of the brightness switching circuit 13 and the engine operation detector 17, which is the current sensing element in the third embodiment.

Although the structure and operation of the automobile watch according to the present invention are clear from the above description, there are cases in which a low-luminance display is sufficient when driving a car at night.

In such a case, in the present invention, a nighttime low brightness display mechanism can be obtained very easily by connecting a nighttime switch intermediately to the signal line from the engine operation detector.

The above-mentioned nighttime switch may be either a manual switch or an illumination light-linked switch.

Furthermore, the engine operation detector in the present invention can be replaced with an engine coolant temperature detector, a charge lamp terminal signal detector, or the like.

As explained in detail above, the automobile watch according to the present invention has the great advantage that it prevents wasteful battery consumption and the time display itself does not stop.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention, FIG. 2 is a schematic diagram showing a second embodiment of the present invention, and FIG. 3 is a diagram showing a second embodiment of the present invention.
4 is a schematic block diagram of a third embodiment of the present invention, and FIG. 5 is a schematic block diagram of a fourth embodiment of the present invention. 10...Timekeeping section, 11...Display section, 1
2...Batch 1 bar 13...Brightness switching circuit, 17...Engine operation detector.

Claims (1)

[Claims] 1. A timekeeping section that includes a reference signal generator, a frequency divider, a counting circuit, and a display signal generator; A display section that includes a drive circuit and a light emitting element; An engine operation detector that detects when the engine is in operation and when it is not in operation; includes a brightness switching circuit that reduces the amount of electricity supplied to the display section when the engine operation detector detects that the engine is not running, and switches the display section from a high brightness display to a low brightness display when the engine is not running; An automobile watch characterized by: