JPS5851633B2 - Digital clock with brightness control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital timepiece with brightness control, and more particularly to a digital timepiece with brightness control that controls time display brightness in a set time zone.

In digital clocks that display the time using self-luminous elements such as gas discharge panels, light-emitting diodes, and electroluminescent elements, the voltage and frequency applied to the self-luminous elements are always kept constant, so the time cannot be displayed. The brightness was constant regardless of the surrounding brightness.

An object of the present invention is to control the display brightness of the time to make the displayed time easier to see when it is predicted that the surrounding conditions will change depending on the time zone, such as nighttime and daytime.

Examples will be described in detail below.

FIG. 1 is a block diagram of an embodiment of the present invention, in which the basic clock signal from the clock generator CLG is transmitted to the divider DV1.
The signal is frequency-divided by the divider DV2 to become the second signal, further divided by the divider DV2 to become the minute signal, and further divided by the divider DV3 to become the hour signal.

The second signal, minute signal, and hour signal are counted by decoders DEC1 to DEC3 each having a counter function, and the count contents are decoded, and the decoded output is the second, minute, and hour drivers DR■1 to DRv3. In addition, the time is digitally displayed by segment selection or dot selection on the display DSP.

Also, the time setting device H8T is used to set the time at which display brightness is switched between daytime and nighttime, and the setting contents and decoder DE
The decoded outputs indicating the time from CI to DEC3 are applied to the brightness control signal generator BSG, the set time is compared with the current display time, and if the comparison matches, a signal is sent to the brightness control circuit BRC to adjust the brightness. The brightness signals applied from the control circuit BRC to the second, minute, and hour drivers DRV1 to DRV3 are changed.

Therefore, at the set time, the display brightness will be switched.

For example, if you set the display to be high brightness from 7:00 to 18:00 and low brightness otherwise, the display brightness during the day will be high and the display brightness at night will be low. Also, the time display becomes easier to read.

Various means can be adopted for display brightness switching control depending on the configuration of the display device DSP.

Generally, the brightness of a self-emissive element changes depending on the applied voltage or the repetition frequency of the driving pulse, so the voltage or repetition frequency of the pulse applied to each driver DRVI to DRV3 from the brightness control circuit BRC is switched in two steps. or the driver D by a signal from the brightness control circuit BRC.
Control can be performed to switch the voltage applied to the display device DSP in RV1 to DRV3.

In addition, a gas discharge panel as a self-luminous element, for example, as shown in FIG. The electrodes 3 and 4 are arranged facing each other with a space I filled with a discharge gas filled therein, and pulse voltages shown as Vx and Vy in FIG. 4 are applied to the electrodes 3 and 4.

This pulse voltage is lower than the discharge starting voltage between the electrodes 3 and 4, and is selected to a value that allows the discharge to occur continuously once the discharge has occurred.
A voltage indicated by Va is applied to the discharge points between 4 and 4, and discharge light is emitted as indicated by PH at the discharge points to which a write pulse is applied such that the voltage exceeds the discharge start voltage.

In addition, when lowering the display brightness by a signal from the brightness control circuit BRC, if the pulse repetition period of voltage Vy is lengthened as shown by y', a voltage Va' is applied to the discharge point, and the write pulse At the discharge point where is applied, discharge light is emitted as indicated by PH'.

In other words, P
Since the number of times of discharge light emission indicated by H' is 1/2, the time average luminance is 1/2.

When the gas discharge panel is used as a self-luminous element in this manner, display brightness can be switched and controlled.

As explained above, the present invention switches the time display brightness of a digital clock at a set time, so it displays at high brightness when the surroundings are bright, such as during the day, and when the surroundings are dark, such as at night. It is possible to switch to a low brightness display to make the time display easier to see.

In addition, the time signal used for displaying the time can be used as the time signal to be compared with the set contents, so display brightness can be controlled by adding only a few parts to a conventional digital clock. can increase product value.

Furthermore, it is possible to use a common time setting device to control the brightness of multiple digital clocks set at multiple locations, and the time setting device H8T is for digitally setting the time, so it is possible to control the brightness at one location. This has the advantage that the time setting and changing thereof are easy, and the structure for comparing with the time signal can also be constructed from a digital circuit.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a sectional view of the main part of a gas discharge panel as a self-luminous element, and Fig. 3 is a block diagram of an embodiment of the present invention.
The figure is an explanatory diagram of switching the display brightness of the gas discharge panel. CLG is a clock generator, DVI to DV3 are frequency dividers, D
EC1 to DEC3 are decoders and DRs including counter functions.
VI~DRV3 are drivers, H8T is time setter, BS
C is a brightness control signal generator, BRC is a brightness control circuit, DS
P is an indicator.

Claims (1)

[Claims] 1. In a digital watch that digitally displays the time using a self-luminous element, a digital time setting device that sets the time in order to reduce or increase the display brightness by a predetermined amount of time within a day; A circuit that compares a set digital signal and a time signal and generates a brightness control signal based on a comparison, and a driver that changes the time display brightness of the self-luminous element based on the brightness control signal from the circuit. . A digital watch with brightness control, characterized in that the time display brightness can be changed continuously for the set time.