JPS61156030A - Antidazzle type reflector for vehicle - Google Patents

Abstract

PURPOSE:To reduce flickering with respect to the variation of backward light and to secure a rear visual field sufficiently by interposing a state having an intermediate reflection factor between the reflection factors of a antidazzle status and a non-antidazzle status into the process turning from the antidazzle status to the non-antidazzle status. CONSTITUTION:When the backward light is reduced and an output from a backward light detecting circuit 14 is turned to '0', the output of a NAND circuit 17 is turned to '1'. Consequently, a charging/discharging circuit 200 gradually executes a charging work on the basis of a time constant based upon a resistor 17 and a capacitor 18 and its output is gradually increased up to '1'. Thereby, the output is inputted to a voltage dividing circuit 100 through an amplifier circuit 20, a resistor 21 and a diode 22 and the divided voltage of the voltage dividing circuit 100 is increased. Consequently, the output of a boosting circuit 10 is gradually reduced and a voltage impressed upon a liquid crystal element 50 is gradually reduced, so that its transmissivity is increased. when the output of the circuit 200 is turned to '1', the liquid crystal is restored to the transparent status and a room mirror is turned to the non- antidazzle status.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an anti-glare reflector for a vehicle that automatically performs an anti-glare operation depending on the amount of light from the rear of the vehicle.

(Prior Art) Conventionally, as a device of this type, there is an anti-glare reflector for vehicles that uses a liquid crystal element to perform an anti-glare operation, and the amount of light from the rear of the vehicle is reduced by the headlights of the following vehicle. When the level exceeds a predetermined level, the transmittance of the liquid crystal element is set to a certain low value to put the reflector in an anti-glare state. The reflector is made to be in a non-dazzling state.

(Problem to be Solved by the Invention) However, in this device, the reflector is switched between a glare-proof state and a non-dazzle state, so the amount of light from the rear of the vehicle is reduced when driving in a city or on a rough road. If it changes intermittently, the reflector will alternate between a dimming state and a non-dazzling state, causing the rear view through the reflector to flicker, causing considerable discomfort and anger to the driver. There is.

Furthermore, in order to eliminate the above-mentioned flicker, some devices are equipped with a delay circuit to continue the anti-glare state for a certain period of time when changing from the anti-glare state to the non-dazzle state.

However, this type does have less flicker (although it does have the problem that the anti-glare state lasts longer, making it difficult to ensure sufficient rear visibility).

The present invention has been made in view of the above-mentioned problems, and aims to reduce the above-mentioned flickering while also ensuring sufficient rearward visibility.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a reflecting mirror in which a transmittance changing means for changing the transmittance in response to a driving signal is provided in front of a reflecting surface, and nighttime detection means for detecting the state of the vehicle; rear light detection means for detecting the intensity of light from the rear of the vehicle; When it is determined that the rear light has become equal to or higher than a predetermined level, the transmittance of the transmittance changing means is set to a constant low value, and when it is determined that the detected rear light has become lower than the predetermined level, the transmittance is set to a constant high value. and a drive control means for driving and controlling the transmittance changing means by supplying a drive signal to the transmittance changing means so that the transmittance changing means changes the transmittance of the transmittance changing means. In the process of driving and controlling the transmittance changing means to change from a certain low value toward a certain high value, the transmittance changing means is maintained at a transmittance between the low value and the high value for a predetermined period of time. The present invention is characterized in that a drive signal changing means is provided for changing the drive signal so as to increase the speed.

(Function) According to the above configuration, when the vehicle is driving at night and the light from the rear of the vehicle exceeds a predetermined level, the transmittance of the transmittance changing means is set to a constant low value, and the reflector is placed in an anti-glare state. do.

In this state, when the rear light decreases below a predetermined level and the condition for setting the reflector to a non-dazzling state is established, the transmittance of the transmittance changing means is changed between the respective transmittances in the dimming state and the non-dazzling state. is maintained at the value for a predetermined period of time, and then the transmittance of the transmittance changing means is set to a constant high value to bring the reflecting mirror into a non-glare state.

(Effects of the Invention) According to the present invention, in the process from the anti-dazzle state to the non-dazzle state, a state with a reflectance between the anti-glare state and the non-dazzle state is interposed, so that flicker is reduced in response to changes in rear light. In addition, since it has a certain degree of reflectance in its interposed state, it has the excellent effect of ensuring sufficient rearward visibility.

(Example) The present invention will be described below with reference to embodiments shown in the drawings.

In this embodiment, an anti-glare reflecting mirror is applied to a room mirror, and as shown in FIG. Transparent electrode layer made of ITo2. 3. Liquid crystal layer that becomes DSM (dynamic scattering mode) when voltage is applied. It has a transparent electrode layer 4, a liquid crystal element composed of a transparent glass substrate 5, and a reflective mirror layer 6 such as C, etc., which forms a reflective surface. Further, as shown in FIG. 3, a rear light sensor 7 is provided at the bottom of the rearview mirror to detect the intensity of light from the rear of the vehicle.Although not shown in the figure, the rear light sensor 7 An ambient light sensor is provided on the back side of the vehicle to detect the intensity of light from the front of the vehicle (light around the vehicle).

FIG. 1 is an electrical wiring diagram of a circuit for anti-glare operation of a rearview mirror. In FIG. 1, 8 is an on-vehicle battery, and 9 is an ignition switch. Reference numeral 10 denotes a booster circuit that boosts the voltage of the battery 8, and operates to boost the voltage from the voltage divider circuit 100 to a constant value. As this booster circuit 10, a switching regulator (for example, TL479 manufactured by Texas Instruments) is used.
(LN integrated circuit). The voltage dividing circuit 100 includes voltage dividing resistors 11, 12 . and a resistor connected in parallel to resistor 11,
It is composed of a thermistor 13. The thermistor 13 is provided inside the rearview mirror, detects the temperature inside the rearview mirror, and has a negative temperature characteristic in which the resistance value changes depending on the temperature. Therefore, when the temperature inside the rearview mirror decreases, the resistance value of the thermistor 13 increases, and the divided voltage at the connection point of the voltage dividing resistors 11 and 12 decreases. 10 increases the output voltage. In other words, if the temperature inside the rearview mirror is low,
The output voltage of the booster circuit 10 increases and the output voltage of the booster circuit 10 fluctuates according to the temperature inside the rearview mirror so that when the temperature inside the rearview mirror is high, the output voltage from the booster circuit 10 becomes lower. . This is because the threshold voltage of the 03M liquid crystal changes depending on the temperature, so the liquid crystal element 50 is operated reliably with respect to the temperature inside the rearview mirror.

Reference numeral 14 denotes a rear light detection circuit, which outputs a "1" signal when the rear light detected by the rear light sensor 7 installed in the rearview mirror exceeds a predetermined level due to the headlights of the following vehicle, etc. Outputs “0” signal when low. In addition,
Hysteresis is provided for the comparison operation with the predetermined level.

Reference numeral 15 is an ambient light detection circuit, which outputs a "1" signal when the ambient light detected by the ambient light sensor installed in the rearview mirror exceeds a predetermined level during the daytime, etc. When it is lower than the level etc., it outputs a “0” signal. Note that hysteresis is provided for the comparison operation with the predetermined level.

An inverter 16 inverts the output signal of the ambient light detection circuit 15. 17 is a NAND circuit. 20
0 is a charging/discharging circuit, and resistor 17. Capacitor 18. When the output of the NAND circuit 17 is inverted from "0" to "I", the resistor 17. Due to the time constant of the capacitor 18, its output gradually increases from 10" to 1", and when the output is "1", the output of the NAND circuit 17 is reversed from "1" to "0". , the capacitor 18 is rapidly discharged via the diode 19, and the output of the charging/discharging circuit 200 rapidly changes from "L" to "O".

20 is an amplifier circuit that amplifies the output signal from the charging/discharging circuit 200, and transmits the output signal to the resistor 21. It is applied to the voltage dividing circuit 100 via the diode 22.

23 is an oscillation circuit that generates an oscillation signal of a predetermined frequency.

An inverter 24 inverts the oscillation signal from the oscillation circuit 23. Transistors 25 and 26 are turned on and off in response to an oscillation signal from the oscillation circuit 23 and an oscillation signal via the inverter 24, and apply respective collector voltages to the liquid crystal element 50. At this time, since the oscillation signal is inverted by the inverter 24, the collector voltages of the transistors 25 and 26 have opposite phases, and an AC voltage is supplied to the liquid crystal element 50.

The operation of the above configuration will be explained.

First, when the ignition switch 9 is off when the vehicle is not in operation, voltage from the battery 8 is not supplied to the various circuits, so the liquid crystal element 50 maintains a transparent state and the rearview mirror does not become in a dim state.

When the ignition switch 9 is turned on while the vehicle is in operation, voltage from the battery 8 is supplied to each circuit.

At this time, when it is bright outside the vehicle, such as during the daytime, the ambient light sensor detects the condition, so the ambient light detection circuit 1
The output of the inverter 16 becomes O', and the output of the NAND circuit 17 becomes 11". As a result, the output of the charging/discharging circuit 200 is 'l''
The amplifier circuit 20. Resistance 21. It is applied to the voltage dividing circuit 100 via the diode 22. By applying this voltage, the divided voltage of the voltage dividing circuit 100 becomes considerably high, so that the output voltage of the boosting circuit 10 becomes so low that it cannot drive the liquid crystal. Therefore, since almost no driving voltage is applied to the liquid crystal element 50, it maintains a transparent state. That is, the rearview mirror maintains a non-dazzling state.

In addition, even if the output of the ambient light detection circuit 15 becomes "0" and the output of the inverter 16 becomes "1" at night, etc., the light from the rear of the vehicle is not so strong and the rear light detection circuit When the output of the NAND circuit 14 is "O", the output of the NAND circuit 17 becomes "1", and by the same operation as described above, the liquid crystal element 50 maintains the transparent state and the rearview mirror does not enter the anti-glare state.

In this state, when the light from the rear of the vehicle due to the headlights of the following vehicle exceeds a predetermined level, the rear light sensor 7 detects this, and the output of the rear light detection circuit 14 becomes "1". Therefore, the output of the NAND circuit 17 is “
In the charging/discharging circuit 200, since the output of the NAND circuit 200 becomes "O", the capacitor 18 is rapidly discharged via the diode 19, and the output from the charging/discharging circuit 200 is instantaneously becomes “0”.

This allows the amplifier circuit 20. Resistance 21. Since no voltage is applied to the voltage divider circuit 100 via the diode 22, the divided voltage from the voltage divider circuit 100 becomes low. Therefore, the booster circuit 10 performs boosting operation to maintain the divided voltage at a constant value.

Then, the boosted voltage is applied to resistors 11, 12. When the divided voltage reaches a constant value due to the action of the thermistor 13 and the like, a stable state is reached and a stable boosted voltage is generated. At this time, due to the action of the thermistor 13, the boosted voltage corresponds to the temperature inside the rearview mirror.

Further, the oscillation circuit 23 performs an oscillation operation to generate an oscillation signal, and by the action of the inverter 24, oscillation signals having different phases are applied to the bases of the transistors 25 and 26. Therefore, the transistors 25 and 26 are turned on and off to exchange the output voltage from the booster circuit 10 into an alternating current voltage and apply it to the liquid crystal element 50. Due to this, the liquid crystal element 50 becomes cloudy and its transmittance decreases. That is,
The rearview mirror becomes dimmed. (Time T1 in Figure 4) When the rear light decreases from this state and the output from the rear light detection circuit 14 becomes 0'', the output of the NAND circuit 17 becomes ``1''.
”. As a result, the charging/discharging circuit 200
7. The capacitor 18 gradually charges due to the time constant, and its output gradually increases toward 1". Therefore, the output is input to the voltage divider circuit 100 via the amplifier circuit 20, resistor 21, and diode 22. and the voltage dividing circuit 10
0 voltage divider circuit is increased. Along with this, booster circuit 1
The output of 0 gradually decreases. As a result, the voltage applied to the liquid crystal element 50 gradually decreases,
Its transmittance increases (from time 12 in Figure 4, T
1) When the output of the charging/discharging circuit 200 becomes "1", the liquid crystal element returns to the transparent state and the rearview mirror enters the non-dazzling state. Note that the period between time Tt and time T8 is set to about 2 to 3 seconds.

After that, when the rear light reaches a predetermined level or higher, the rear view mirror is instantly set to the anti-glare state in the same way as above (time 14 in Figure 4), and when the rear light falls below the predetermined level, the rear view mirror is gradually unprotected. During the changing process, when the rear light reaches a predetermined level or higher, the glare-proof state is instantaneously changed from that point onwards.

(Time T2 in FIG. 4) Therefore, since there is little change in transmittance at this time, flickering can be further reduced.

In addition, in the above embodiment, when the conditions for making the non-dazzling state are established, the transmittance is immediately changed toward the non-dazzling state, but after a slight delay,
The transmittance may be continuously changed toward the non-glare state. An example of this is shown in FIG. The circuit shown in FIG. 5 has a resistor 27. on the output side of the rear light detection circuit 14.
Capacitor 28. Delay circuit 30 consisting of diode 29
0, and when the amount of light from the rear of the vehicle exceeds a predetermined level and the output of the rear light detection circuit 14 becomes "1", the diode 29. Rapidly charged by capacitor 28,
The output is instantly set to "1" and the output of the NAND circuit 17 is set to "O" to immediately bring about the anti-glare state. When the rear light falls below a predetermined level from this state, the output of the rear light detection circuit 14 becomes 0'', but the resistor 28 and capacitor 2
After a slight delay time (for example, 1 second) has elapsed due to the action of 8, the output of the NAND circuit 17 becomes 1", and the state shifts to the non-dazzle state. In this case, the charging/discharging circuit 200
Resistance 17. The time constant provided by the capacitor 18 may be made smaller so that the non-glare state is entered earlier than that shown in FIG.

Further, in each of the above embodiments, the transmittance is continuously changed from the anti-glare state to the non-glare state, but the transmittance may be changed stepwise. An example of this is shown in FIG. The device shown in FIG. 6 uses a negative type G/H liquid crystal whose transmittance increases when a voltage is applied as the liquid crystal, and has a two-layer structure. Therefore, the liquid crystal element 60 has a G/H liquid crystal interposed between three layers of transparent electrodes 61, 62 and 63.

Furthermore, exclusive OR circuits 30 and 31 are provided to apply oscillation signals to the transparent electrodes 61 and 63 of the liquid crystal element 60. Note that voltage is supplied to these circuits from the vehicle battery when the ignition switch is closed.

In the circuit shown in FIG. 6, during the daytime or when the rear light is not very strong, the output of the NAND circuit 17 is "
Since one input of the exclusive OR circuit 30 and 31 is "1", its output is an oscillation signal that is inverted from the oscillation signal from the oscillation circuit 23, which is the other input. Therefore, transparent electrodes 61, 62 and 62.
A voltage is applied between 63 and the liquid crystal element 60 maintains a transparent state.

From this state, when the conditions for setting the rearview mirror to the anti-glare state are established and the output of the NAND circuit 17 becomes "0", the output of the charge/discharge circuit 200 instantly becomes "O", so the exclusive OR circuit 30. 31 becomes "O", and its output becomes an oscillation signal that is in phase with the oscillation signal from the other human-powered oscillation circuit 23. Therefore, the transparent conductor 1M61.62.
Since an oscillation signal of the same phase is applied to 63, no voltage is applied between the respective electrodes, the transmittance of the liquid crystal element 60 decreases, and the rearview mirror becomes in an anti-glare state.

From this state, when the conditions for turning the rearview mirror into a non-dazzling state are established and the output of the NAND circuit 17 becomes "1", one input of the exclusive OR circuit 31 becomes "1'", so that the transparent electrode 62. A voltage is applied between 63 and the liquid crystal layer therebetween becomes transparent.

However, in the charge/discharge circuit 200, its output does not become "L" immediately due to its action, so the output of the exclusive OR circuit 30 becomes an oscillation signal that is in phase with the oscillation signal from the oscillation circuit 23, and the transparent electrode 61 No voltage is applied between .62 and the liquid crystal layer between the transparent electrodes has a low transmittance of mVt. Therefore, the liquid crystal element 60 has a transmittance intermediate between that during anti-glare and non-anti-glare.

Thereafter, when the output of the charge/discharge circuit 200 becomes high and the output of the exclusive OR circuit 30 becomes a signal obtained by inverting the phase of the oscillation signal from the oscillation circuit 23, a voltage is applied between the transparent electrodes 61 and 62, and the transparent The liquid crystal layer between the electrodes becomes transparent. Therefore, the liquid crystal element 60 is in a transparent state, and the rearview mirror is in a non-glare state.

In addition, in the above example, a two-layer type 〇/H liquid crystal element was used to make the change stepwise, but in the DSM liquid crystal, two
It is also possible to use an IN liquid crystal element mixed with a chromatic dye and change the applied voltage to change it to G/H-DSM, thereby changing its transmittance.

In addition, although a device is shown in which the ambient light detection circuit 15 is provided for nighttime detection, a light switch is used to turn on the headlights, and when the light switch is turned on, voltage is supplied from the battery to each circuit to activate the anti-glare operation. You may also be able to do this.

Further, although the present invention has been described as being applied to a room mirror, it may also be applied to a side mirror.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram showing one embodiment of the present invention, Fig. 2 is a cross-sectional view of the reflecting mirror section, Fig. 3 is a front view of the room mirror, Fig. 4 is an explanatory diagram for explaining the operation, Fig. 5 The figure is a main part electric circuit diagram showing another embodiment of the present invention, and FIG. 6 is an electric circuit diagram showing still another embodiment of the present invention.

Claims (3)

[Claims] (1) A reflector that has a transmittance changing means in front of its reflecting surface that changes its transmittance in response to a drive signal, a night detection means that detects nighttime conditions, and the intensity of light from the rear of the vehicle. and a rear light detection means for detecting the change in transmittance when it is determined that the rear light detected by the rear light detection means has exceeded a predetermined level while the nighttime detection means is detecting a nighttime state. The transmittance of the means is set to a constant low value, and when it is determined that the detected rear light has decreased below a predetermined level, a drive signal is supplied to the transmittance changing means so as to set the transmittance to a constant high value. and a drive control means for driving and controlling the transmittance changing means, wherein the transmittance of the transmittance changing means is changed from a constant low value toward a constant high value. In the process of driving and controlling the transmittance changing means, a drive signal changing means is provided for changing the drive signal so that the transmittance changing means maintains the transmittance between the low value and the high value for a predetermined period of time. An anti-glare reflector for vehicles featuring: (2) The driving signal changing means changes the driving signal so that the transmittance of the transmittance changing means gradually increases continuously from a certain low value to a certain high value. An anti-glare reflector for a vehicle according to claim 1. (3) The drive signal changing means changes the drive signal so that the transmittance of the transmittance changing means is held at a constant value between the low value and the high value for a predetermined period of time. An anti-glare reflector for a vehicle according to claim 1.