JPH0627425A - Electronic sunglasses - Google Patents

Abstract

PURPOSE:To prevent transmissivity from being varied frequently even if external illuminance is varied by setting illuminance whose transmissivity is varied from high to low, to higher illuminance than illuminace whose transmissivity is varied from low to high. CONSTITUTION:When a voltage applied to a resistance 7 of a solar battery 1 does not reach, for instance, 3V, an output signal 19 becomes a turn-off signal (L) and the same phase (L) is applied to a liquid crystal cell (subjected to light shielding, when a voltage is applied) 2, and it does not operate. When a voltage exceeding 3V of a voltage detecting level is applied, the output signal 19 of a voltage circuit 3 outputs a turn-on signal (H), and an AC signal of an oscillating circuit 4 becomes an opposite phase and is applied to a liquid crystal cell from inverters 17, 18. A capacitor 9 applies a voltage for a while to a voltage detecting circuit, when transmissivity is varied from low to high, and allows it to have a time lag. In such a state, when the external illuminance is varied and operated, transmissivity is varied from high to low at 20000 Lux, and varied from low to high at 5500 Lux.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic sunglasses having a variable transmittance, which utilizes a liquid crystal electro-optical effect and has a solar cell as a power source for driving the liquid crystal.

[0002]

2. Description of the Related Art The concept of sunglasses having variable transmittance using liquid crystal has been presented in the past. As a general concept, FIG. 1 described in JP-A-48-98846,
FIG. 3 described in JP-A-51-124936, FIG. 1 described in JP-A-62-127524, and JP-A-62-
5 and 7, as described in 40425, Showa 55-
Fig. 1 described in 95106, 59-1786
FIG. 18 described in FIG. 18 and FIG. 1 described in Japanese Utility Model Application Laid-Open No. 62-109137, and a combination of a liquid crystal panel which is a transmittance variable section, a power supply, a drive circuit, a control circuit, and a light detection section. It is known to make up electronic sunglasses.

[0003]

In the sunglasses having variable transmittance using the electro-optical effect of liquid crystal, setting the illuminance at which the transmittance changes from high to low and the illuminance at which the transmittance changes from low to high have important meanings. . When these illuminances match, the transmittance changes with one illuminance, and when the illuminance changes before and after the matched illuminance, the transmittance also frequently changes from high to low and low to high, which is very annoying. . There are various situations in which the illuminance changes greatly, such as when driving between trees.

[0004]

SUMMARY OF THE INVENTION The present invention provides a variable transmittance electronic sunglasses using an electro-optical effect of liquid crystal and a solar cell as a power source, since the illuminance at which the transmittance changes from high to low is low. The feature is that the illuminance is higher than the illuminance that changes to high.

In order to differentiate the illuminance at which the transmittance changes, the voltage generated by the solar cell is divided, the voltage set by the voltage detection circuit is detected, and the liquid crystal is driven. A method is conceivable in which a capacitor is connected in parallel to the voltage detection unit of the circuit to delay the change of the transmittance from low to high in time, thereby making the transmittance change illuminance substantially different. In addition, like sunglasses, if the volume of the frame is small and a large capacity condenser cannot be stored,
It is also useful to use a method in which the operating voltage of the voltage detection circuit has hysteresis.

[0006]

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

(First Embodiment) FIG. 1 is an external view of a first embodiment of the present invention. Solar cell 1, Lens with liquid crystal cell 2
(The lens 2 with a liquid crystal cell is configured to block light when a voltage is applied.).

FIG. 2 is a circuit diagram of an embodiment of the present invention. Of the solar cell 1, the liquid crystal cell 2, the voltage detection circuit 3, the oscillation circuit 4, the liquid crystal drive circuit 5, the voltage dividing resistors 6 and 7, the power protection capacitor 8, the capacitor 9 for delaying the switching timing of the transmittance, and the voltage detection circuit. It is composed of a resistor 10 for giving a hysteresis to the operating voltage.

The oscillator circuit 4 includes NAND gates 11 and 12,
It is a CR oscillation circuit including a capacitor 13 and a resistor 14. (In the present invention, the type of the oscillation circuit is not limited. It is shown as an example.) Further, the liquid crystal drive circuit 5 controls the output N.
It is composed of AND gates 15 and 16 and inverters 17 and 18. The details of the voltage detection circuit 3 are well known and will not be described. The power protection capacitor 8 is connected in parallel with the circuit.

The electromotive force of the solar cell 1 is divided by the resistors 6 and 7. The detection level of the voltage detection circuit is set to 3V, and when the voltage applied to the resistor 7 does not reach 3V, the output signal 19 is an off signal (L) and the liquid crystal cell 2 is in phase (L).
The voltage of is applied and does not work. Voltage detection level of 3V
When a voltage exceeding 1.0 is applied, the output signal 1 of the voltage circuit 3
Since 9 outputs the ON signal (H), the AC signal of the oscillation circuit 4 is applied to the liquid crystal cell in a reverse phase from the inverters 17 and 18. Driving frequency is resistance 14, capacitor 1
It is determined by 3 and several tens to several hundreds Hz is suitable.

The capacitor 9 applies a voltage to the voltage detection circuit for a while when the transmittance changes from low to high,
By giving a time lag, the illuminance at which the transmittance changes is shifted, and the one having 4.8 μm or less was used.
I couldn't mount a large-capacity condenser due to the thin frame of the glasses. The voltage dividing resistors 6 and 7 are 200 KΩ resistor 7 and 1 MΩ resistor 7 so that the illuminance in the external environment is 20000 Lux and 3 V or more is applied to the voltage detection circuit. 1 MΩ was used for the resistor 10 that gives the operating voltage of the voltage detection circuit hysteresis. The power supply protection capacitor 8 removes noise and ripples to the power supply and is preferably about several tens of μF.

When the illuminance in the external environment was actually changed and operated, the transmittance changed from high to low at 20000 Lux and from low to high at 5500 Lux.

[0013]

As described above, according to the present invention, the illuminance in which the transmittance is low to high and the illuminance in which the transmittance is high to low are not matched, so that the illuminance does not change with one illuminance. Therefore, even if the illuminance in the external environment changes slightly near a certain illuminance, the transmittance does not change frequently, and the illuminance in the external environment changes frequently when driving in a grove or when driving in the city. No longer bothered at times. This made it possible to obtain electronic sunglasses for actual use.

[Brief description of drawings]

FIG. 1 is an external view of electronic sunglasses according to a first embodiment.

FIG. 2 is a circuit diagram of the first embodiment.

[Explanation of symbols]

 1 Solar cell 2 Liquid crystal cell 3 Voltage detection circuit 4 Oscillation circuit 5 Liquid crystal drive circuit

Claims (1)

[Claims] 1. In a sunglasses with variable transmittance, which uses an electro-optical effect of liquid crystal and a solar cell as a power source, the illuminance at which the transmittance changes from high to low is higher than that at which the transmittance changes from low to high. Electronic sunglasses characterized by being.