JPH02175359A - Automatic operation device for rear window defogger - Google Patents

Abstract

PURPOSE:To remove cloudiness automatically by providing a cloudiness detector detecting cloudiness of a rear window glass and, according to a signal detected by the cloudiness detector, starting to energize a heating coil provided on a rear window glass. CONSTITUTION:A cloudiness detector 1 detecting cloudiness of a glass WG is provided on the inner side of a rear window glass WG in which heating coil is provided. The cloudiness detector 1 is constructed of a reflection type optical sensor 4 in which light is applied from an infrared LED5 on an emission side toward the glass WG and its reflected light is reflected by a phototransistor on a light receiving side. When the glass WG is cloudy where the light from the LED 5 is liable to be reflected light injected in the phototransistor 6 is increased, and, when the phototransistor 6 is turned on, the heating coil 2 is started to be energized through a heating coil driving circuit 3 and the cloudiness of the glass WG is removed by the emitted heat.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application 1] The present invention relates to an automatic rear window defogging device for defogging a rear window glass of an automobile.

[Prior art 1] Automotive rear windshields are equipped with a method of removing frost and fog on the outside, as well as dew condensation on the inside.
A heat wire (default rear window) is installed. Previously, the heating wires had to be energized by a passenger operating a manual switch.

[Problem to be solved by the invention 1 However, the rear window defogger consumes a large amount of current, so if it is manually operated like the conventional device, a large amount of power will be wasted if the switch is forgotten prematurely. There were drawbacks. Also, since it takes time for the fog to be removed by the heat from the hot rays after the power is turned on, if you notice the occurrence of fog too late, the fog removal will not open properly when you actually want rearward visibility. There was also a drawback.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the automatic operation device for a rear window glass 7-year-old moth of the present invention, as shown in FIG. and a hot wire drive circuit 3 that energizes the hot wire 2 disposed on the rear window glass WG in response to the fogging detection signal generated by the fogging detector 1.

[Operation] In the above device, when fogging occurs on the rear window glass WG, the fogging detector 1 detects it and generates a fogging detection signal. Then, the hot wire drive circuit 3 energizes the hot wire 2 arranged on the rear window glass WG in response to the fogging detection signal. Then, the heating wire 2 generates heat by energizing, and the fogging is removed.

When the fog is removed, the fog detection signal from the fog detector 1 disappears, so the hot wire drive circuit 3 stops energizing the hot wire 2.

[Example 1 An embodiment of the present invention will be described below with reference to FIG.

FIG. 2 is a circuit diagram of a rear defroster operating device according to an embodiment. A hot wire 2 is arranged on the inner surface of the rear window glass WG, and a fogging detector for detecting fogging of the glass WG is equipped on the inside of the glass WG. In this embodiment, a reflective optical sensor 4 is used as a fogging detector.

This sensor 4 is of a type in which the rear window emits light from an infrared LED (infrared light emitting guide 1') 5 on the light emitting side toward the rear window WGf, and the reflected light is received by the light receiving side E)). be. However, when the last WG is not cloudy, the light from the LEDS passes through the plus WG and there is little reflected light that enters the phototransistor, so the phototransistor 6 is turned off. Furthermore, when the glass WG is cloudy, the glass WG is in a state where it easily reflects the light from the LEDS, and the amount of reflected light that enters the phototransistor 6 increases, so the phototransistor 6 is turned on.

In addition to the above configuration, the device of this embodiment also includes an operation switch 7 for selecting whether to operate the rear defroster automatically or manually, a relay 8 for driving the hot wire 2, and a relay 8 for driving the relay 8. A relay 9 for driving the relay 9, a transistor 10 with a large allowable current value for driving the relay 9, a voltage stabilizing circuit 11 for stabilizing the operating voltage of each element, etc.
I have.

One end of the hot wire 2 is connected to the positive electrode of the battery B via the switching contact of the relay 8, and the other end is connected to the ground circuit. In addition, the operation switch 7 has a manual on (MAN ON) contact and an automatic (AUTO) contact as an output terminal.
), and the input end is connected to the positive electrode of battery B. In addition, the single excitation coil of the relay 8 is
One end is connected to the positive electrode of the battery B via the manual on contact 7a of the operation switch 7 and the opening/closing contact of the relay 9, and the ground end is connected to the earth circuit.

The excitation coil of the relay 9 has one end connected to the automatic contact 7b of the operating switch 7 via the voltage stabilizing circuit 11, and the other end connected to the ground circuit via the transistor 10. The base of this transistor 10 is a resistor 12
is connected to the emitter of the phototransistor which constitutes the optical sensor, t. This emitter is connected to a ground circuit via a resistor 13.

Furthermore, the input 1 of the sensor 4 (the anode of the LED 5 and the flip-flop of the phototransistor 6) is connected to the automatic contact 7b of the operation switch 7 via the voltage stabilization circuit 11. Note that a resistor 14 is inserted between the LEDS and the voltage stabilizing circuit 11. Further, the cathode of the LEDS is connected to a ground circuit. In this embodiment, a circuit including a relay 8.9 and a transistor 10 constitutes a hot wire drive circuit 3.

In the device configured in this way, the operation switch 7
If it is set to OFF (OFF> position, the hot wire 2 will not be energized. Also, if you want to operate it manually, set the operation switch 7It to the manual ON (MAN○N) position. Then, the coil of relay 8 will be turned on. Current flows and the opening/closing contact closes, and current is supplied directly from batch 17-B to heat #!2, causing heat wire 2 to generate heat.

In addition, if you want to operate automatically, turn the operation switch 7 to automatic (
Leave it in the AUTO) position. Then, window glass WGl: When there is no fogging, the light from the LEDS passes through the window glass WG and there is little reflected light, so the phototransistor 6 is turned off, the transistor 10 is turned off, the relay 9 is inactive, and the relay 8 becomes inactive and heats up! 2 is not energized.

Further, when the window glass WGi becomes foggy, reflected light increases, the phototransistor 6 is turned on, and the transistor 10 is turned on. Then, relay 9 is activated and R
The M contact closes, current flows through the coil of relay 8, and the opening/closing contact closes. Then, the heating wire 2 is energized, and the fog is removed by the heat of the heating wire 2. When the fog is removed, the phototransistor 6 is turned off, and the power supply to the hot wire 2 is stopped.

As described above, according to the device of the embodiment, the operation switch 7
As long as it is set to the automatic (AUTO) position, the power to the heat [2] is automatically turned on and off.

In the above embodiment, a case has been described in which the reflective optical sensor 4 is used as the fogging detector, but a known dew condensation sensor or the like may be used as the fogging detector. In this case, the sensor can also be attached to the glass surface. Further, in the above embodiment, the phototransistor 6
relay 8 is activated by the output of It is also possible to control the intensity analogously.

[Effects of the Invention] As described above, according to the rear window defogger automatic operation device of the present invention, when the rear window glass becomes foggy, the heating wire is automatically energized to remove the fogging.

Further, when the fog is removed, the power supply is automatically stopped. Therefore, wasted power due to forgetting to turn off the switch)■
There will be no expenses. Additionally, if fogging occurs, a defogging operation is automatically performed, so any fogging that occurs is cleared without the occupants noticing, ensuring good rearward visibility at all times.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIG. 2 is a circuit diagram of an embodiment of the present invention. WG・・・Rear window glass, 1・・・・・・
Fogging detector, 2... Heat ray, 3... Heat ray drive circuit, 4... Optical sensor (fogging detector).

Claims (1)

[Claims] A fog detector that detects fogging on the rear window glass,
An automatic operation device for a rear window defogger characterized by comprising a hot wire drive circuit that energizes a hot wire arranged on the rear window glass in response to a fogging detection signal generated by the fogging detector.