JPS61234496A - Automatic dimmer display - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applied to portable equipment used both indoors and outdoors, or during the day and at night, and automatically adjusts the brightness to an appropriate level according to the surrounding brightness. The present invention relates to an automatic dimming display that emits light at different angles.

Conventional technology Conventionally, in devices without a dimming function, when the surroundings are bright, such as outdoors during the day, the display becomes difficult to see due to reflections on the display panel surface, and when the surroundings are dark, such as at night, it is necessary to The brightness is too bright, causing eye fatigue and consuming unnecessary electrical energy. In order to solve this problem, a manually controlled display device is known.

Problems that the invention aims to solve: Manually dimming displays are complicated to operate;
There are problems such as an increase in the number of mechanical damage factors and a deterioration in the maintainability of the equipment.

The present invention solves the difficulty of viewing the display by automatically increasing the luminescence of the display element when it is bright without human intervention, and reduces the brightness of the display to the minimum necessary when the surroundings are dark. This control prevents too much brightness and the labor costs of electrical energy.

Means for Solving the Problems The automatic dimming display of the present invention includes an illuminance detection element whose resistance value changes depending on the illuminance, a voltage comparator that compares the terminal voltage of this illuminance detection element with a reference voltage, A transistor whose conduction is controlled by the output of this voltage comparator, a diode whose gate and cathode are shorted by the conduction of this transistor, and a diode which is connected to the power supply through this diode and whose luminous intensity changes with changes in the applied voltage. It is equipped with a display element.

Effect With the above configuration, the resistance value of the illuminance detection element changes depending on the illuminance, and this change in resistance value changes the output of the voltage comparator, causing the transistor to become conductive or non-conductive. do. That is, the cathode and gate of the diode may or may not be short-circuited. As a result, the voltage applied to the display element changes depending on whether or not a voltage drop occurs due to the diode, and the emission intensity of the display element changes.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, Zl is an illuminance detection element such as a CaS light receiving element whose resistance value changes depending on the illuminance, and resistor R10i
It is connected to the power supply IC1 via the power supply IC1.

The voltage VZ generated across the illuminance detection element z1 is determined by the voltage comparators CP1, CF2, CF2, . . .
- Input to one input terminal of CPn. The voltage of power supply E1 is determined by resistors R20, R21, R22, R23...
The voltage v1 at the connection point of the resistor R20 and the resistor R21, which is divided by a series circuit consisting of R2H, is input to the input terminal of the voltage comparator CP1. Maku, Resistor R21 and Resistor R
The voltage v2 at the node No. 22 is input to the input terminal of the voltage comparator CP2. The same applies hereafter, and the resistance R2(n-
1) and the voltage Vn at the connection point of the resistor R2n is determined by the voltage comparator CP.
It is connected to the ten input terminals of n. Ql, Q2I°°°
°°°IQn are transistors, each with a resistor R3
1, R32, ...... Voltage comparator CP1・CF2・°° via R3fi.

..., connected to the output terminal of CPn, and each voltage comparator C
P1. CP2. . . . are controlled to be conductive or non-conductive by the output signal of GPn. Dl.

D2. . . . , Dn are diodes, and transistors Q1 . Q2+..., connected in parallel to Qn, each transistor Q11Q21...,
When Qn becomes conductive, the gate and cathode are short-circuited. Mano, each diode DI, D2. ..., Dn are connected in series. Dp is a display element whose emission intensity changes depending on the applied voltage, and is a diode DI.

D2. ......, power supply E2 via a series circuit of Dn.
It is connected to the.

As shown in FIG. 2, the illuminance detection element z1 has a characteristic in which the terminal voltage vz increases as the surrounding illuminance increases. However, in FIG. 2, it is shown to have a linear characteristic for convenience.

In the above configuration, considering a case where the illuminance gradually shifts from a high state to a low state, the terminal voltage VZ of the illuminance detection element z1 sequentially changes to Vl, V2, .・・・・・・Vni becomes lower than the voltage comparator CP1゜cpm,・・・・
...The output of CPn goes from L level to H level one after another, and F transistor Q 1g Q 21...
...Qn changes from ON to OFF. This state is shown in Figure 2 as Q' + Q2...
・This is the waveform of Qn.

Now, transistor Q' + Q2+...
As Qn is sequentially turned off, the voltage VD applied from the power source E2 to the display element Dp gradually increases to the diode DI,
D2.・・・・・・Voltage drop due to Dn VF1゜YF2
．． . . . Decreases depending on VFn. This situation is shown in the lower part of FIG. Therefore, the brightness of the display element Dp is gradually weakened, and the power consumption is reduced.

Effects of the Invention As is clear from the above explanation, according to the present invention, it is possible to automatically adjust the light according to the surrounding brightness with a relatively simple structure, and the number of steps of dimming depends on the purpose of the device, etc. It can be selected arbitrarily. That is, reasonable display brightness can be provided in various portable devices.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an automatic dimming display according to an embodiment of the present invention, and FIG. 2 is a detailed characteristic diagram showing synchronized dimming operation. E2...Power supply, zl...Illuminance detection element, CP1-CPn...Voltage comparator, Q1-Qn
...Transistor, D1-Dn...Diode, Dp...Display element. Name of agent: Patent attorney Toshio Nakao and one other person Z/
--One illuminance cane element Crt-C---List comparison 1 Dp --One table 7rX Keiko

Claims (2)

[Claims] (1) An illuminance detection element whose resistance value changes depending on illuminance;
A voltage comparator that compares the terminal voltage of this illuminance detection element with a reference voltage, a transistor whose conduction is controlled by the output of this voltage comparator, a diode whose gate and cathode are shorted by conduction of this transistor, and this diode. An automatic dimming display equipped with a display element that is connected to a power source through a power supply and whose luminous intensity changes according to changes in applied voltage. (2) Multiple sets of voltage comparators, transistors, and diodes are provided, the reference voltage input to each set of voltage comparators is different, the diodes of each set are connected in series, and the light emitting elements are connected in series. An automatic dimming display according to claim 1, connected to a power source through each set of diodes.