JP3249720B2 - Auto-dimming mirror - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic anti-glare mirror (EC anti-glare mirror) used for an inner mirror, an outer mirror and the like of a vehicle. To reduce the glare and reduce the glare immediately when the rear suddenly becomes dazzling due to the headlights of the following vehicle at night, and to expand the continuously variable reflectance area. It is a thing.

[0002]

2. Description of the Related Art In general, an EC anti-glare mirror covers the front surface of a mirror reflection surface with an EC (electrochromic) element film.
By controlling the reflectance by changing the coloring amount of the EC element, an anti-glare effect can be obtained for headlights of a following vehicle at night or the like. In order to obtain such an anti-glare effect, the anti-glare mirror detects the amount of incident light from the rear direction, increases the amount of coloring when the rear light is bright (reduces the reflectance), and darkens the rear light. At the time, control is performed so as to reduce the coloring amount (decoloring, that is, increasing the reflectance).

As a driving device for an EC anti-glare mirror, there is Japanese Patent Application No. 6-99291 filed by the present applicant. This is to detect the ambient light amount and the rear light amount, generate a pulse signal whose duty ratio changes accordingly, and drive the EC element based on this pulse signal to continuously change the reflectance of the mirror. It is like that. This EC
FIG. 2 shows a control block diagram of the anti-glare mirror driving device.

The ambient light amount detecting means 10 detects the amount of light around the vehicle, and is disposed, for example, in a mirror housing of an inner mirror or an outer mirror toward the front of the vehicle. The rear light amount detecting means 12 detects the light amount from behind the vehicle, and is disposed, for example, in a mirror housing toward the rear of the vehicle.

The oscillating means 14 generates an oscillating signal which alternately repeats "H" level and "L" level.
The “H” level duration and the “L” level duration are individually controllable. Oscillation means 1
The oscillation cycle of No. 4 is desirably 10 ms or less so that the decoloring and the flickering of the coloring cannot be recognized by human eyes. The inversion cycle control means 16 variably controls the duration of one level of the oscillation signal generated from the oscillation means 14 according to the light quantity detected by the ambient light quantity detection means 10. In addition, the duration of the other level of the oscillation signal is variably controlled in accordance with the light amount detected by the rear light amount detecting means 12.

[0006] The EC element 20 is formed on the front surface of the mirror reflection surface. The driving power supply 22 supplies driving power to the oscillating means 14, the EC element driving means 24, and the like. EC
The element driving unit 24 inverts the polarity of the driving voltage according to the level of the oscillation signal generated from the oscillation unit 14 and applies the inverted driving voltage to the EC element 20 to thereby change the coloring amount according to the duty ratio of the oscillation signal. Control.

The contents of control of the duty ratio by the inversion cycle control means 16 are as follows. That is, the EC element driving means 24 outputs the EC element 20 at one level of the oscillation signal.
Is driven in the coloring direction and the EC element 20 is driven in the decoloring direction at the other level, the inversion cycle control means 16 determines the duration of the one level when the ambient light amount is large. When the amount of ambient light is small, the duration of the one level is lengthened, and when the amount of rear light is large, the duration of the other level is shortened, and when the amount of rear light is small, the duration of the other level is reduced. Lengthen. Also,
The EC element driving means 24 outputs the E signal at one level of the oscillation signal.
When the C element 20 is set to be driven in the decoloring direction and the EC element 20 is driven in the coloring direction at the other level, the inversion cycle control means 16 sets the level of the one level when the ambient light amount is large. When the amount of ambient light is small, the duration of one level is shortened, and when the amount of rear light is large, the duration of the other level is extended, and when the amount of rear light is small, the level of the other level is reduced. Decrease duration.

[0008] By such control, the coloring amount is continuously controlled. That is, when the ambient light is dark, the sensitivity to the rear light increases, and the amount of coloring increases as the amount of the rear light increases, the reflectance decreases, and an anti-glare state is obtained. Further, when the ambient light is bright, the sensitivity to the rear light is reduced, the coloring becomes difficult, and the high reflectance is maintained.

FIG. 3 shows a specific example of the EC element driving means 24 shown in FIG. As shown in FIG. 4, the oscillation signal output from the oscillating means 14 in FIG. 2 changes the period t1 of the "H" level in accordance with the rear light amount (the shorter the brighter, the shorter the period).
The “L” level period t2 changes according to the amount of ambient light (it becomes shorter as it becomes brighter). EC element driving means 24
Is complementary between about ± 1.6V of positive and negative power supply voltage.
It has two switching transistors Q1 and Q2 connected in a push-pull connection. A resistor R is connected between the power supply line of about +1.6 V and the output terminal of the oscillation means 14.
6, R7 are connected in series, and the voltage at the connection point of the resistors R6, R7 is applied to the base of the transistor Q1. Further, resistors R8 and R9 are connected in series between the power supply line of about -1.6 V and the output terminal of the oscillating means 14, and the voltage at the connection point of the resistors R8 and R9 is applied to the base of the transistor Q2. ing. With such a configuration, the oscillation means 1
When the output of No. 4 is at "H" level, the transistor Q1 is turned off and the transistor Q2 is turned on to supply the EC element 20 with energy in the decoloring direction. When the output of the oscillating means 14 is at "L" level, the transistor Q1 is turned on and the transistor Q2 is turned off, and the energy in the coloring direction is supplied to the EC element 20. Here, the transistor Q
1 and Q2 have a resistor R1 as an energy supply limiting element.
Since 0 and R11 are connected in series, energy supply (current supply) in the coloring direction and the decoloring direction is restricted,
Power consumption and heat generation in the EC element 20 are suppressed. Also, since the EC element 20 is electrically the same as the capacitance,
A time constant circuit is formed between the resistors R10 and R11 (R1
0 and R11 are, for example, about 5Ω), and the response speed of coloring and decoloring is reduced. Therefore, when traveling at night, it is possible to prevent coloring and decoloring from being frequently repeated by streetlights, lights of shops, lights of oncoming vehicles, etc., thereby causing annoyance.

FIG. 5 shows the relationship between the duty ratio (t1 / (t1 + t2)) of the driving pulse and the mirror reflectance by the EC element driving means 24 in FIG. In this circuit, when the duty ratio of the input pulse signal increases, the EC element 2
Since 0 goes in the decoloring direction, the reflectance increases, and when the duty ratio decreases, the EC element 20 moves in the coloring direction, so that the reflectance decreases. In addition, a value (b
When the mirror reflectance is larger than the point (point), the mirror reflectance becomes substantially constant at the highest reflectance (for example, 70%). When the mirror reflectance becomes smaller than a certain value (point a), the mirror reflectance becomes substantially constant at the lowest reflectance (for example, 10%). A region where the reflectance changes continuously between the point b and the point b (hereinafter, referred to as a “continuously variable reflectance region”).
become. In the continuously variable reflectance region, the ratio of the change in the reflectance of the mirror to the duty ratio is substantially constant.

According to the EC element driving means 24 shown in FIG. 3, since the coloring current supplied to the EC element 20 is limited by the resistor R10, the mirror is immediately colored when the rear portion at night suddenly becomes dazzling. You may feel annoying because it is not cut. If the resistance R10 is reduced, the response in the coloring direction becomes faster, so that such annoyance can be eliminated. However, if the values of the resistors R10 and R11 are reduced, coloring and decoloring are frequently repeated for a slight change in light, and this causes annoyance. When the values of the resistors R10 and R11 are reduced, the ratio of the change in the mirror reflectance to the change in the duty ratio increases as shown in FIG. 6 (the reason why the ratio of the change in the mirror reflectance changes even when the duty ratio is the same). This is because the amount of energy supplied to the mirror is changed by changing the value of the current supplied to the mirror.) The continuously variable reflectivity area is narrowed, and the reflectivity is increased with a slight change in the amount of light. It fluctuates and gives another annoyance.

[0012] Therefore, by solving such a problem, it is possible to prevent the reflectance from frequently changing or greatly fluctuating for a slight change in the amount of light to make the driver feel troublesome, Japanese Patent Application No. Hei 6-301322 discloses an automatic anti-glare mirror which improves the responsiveness when the rear is suddenly dazzled by the headlights of a car and is capable of immediately coloring and reducing dazzling. No. proposed. This is achieved by providing a response speed control means for controlling the response speed of the EC element according to the amount of rear light. When the amount of rear light is small, the response speed in the coloring direction of the EC element is reduced, and when the amount of rear light is large, the EC element is controlled. Is controlled to increase the response speed in the coloring direction. According to this, when the rear light amount is small, the response speed of the EC element in the coloring direction is slowed, so that it is possible to prevent the reflectance from frequently changing with a slight change in the light amount. When the amount of rear light is large, the response speed of the EC element in the coloring direction is increased. Therefore, when the headlight or the like is suddenly illuminated from behind at night, the EC element can be colored immediately to reduce glare.

FIG. 7 shows a control block of this automatic anti-glare mirror.
Shown in 2 are denoted by the same reference numerals. The coloring current variable circuit 34 corresponds to a response speed control unit. The coloring current variable circuit 34 supplies a driving current in the coloring direction to the EC element 20 in parallel with the EC element driving means 24, and automatically turns the circuit 34 on and off in accordance with the detected light amount. The driving current value in the coloring direction to be supplied to 20 is switched. For example, when the rear light amount is small, the coloring current variable circuit 34 is turned off, and E
When a driving current is supplied only from the C element driving means 24 and the rear light amount is large (for example, when the rear suddenly becomes dazzling at night).
Turns on the coloring current variable circuit 34 to supply the driving current from both the EC element driving means 24 and the coloring current variable circuit 34.

The coloring current variable circuit 34 includes a coloring current variable determination circuit 36 and a coloring current variable EC element driving means 38. The coloring current variable determination circuit 36 captures the oscillation signal output from the oscillating unit 14 and determines whether to supply a driving current from the coloring current varying EC element driving unit 38 according to the duty ratio or the like. The coloring current variable EC element driving means 38 includes a coloring current variable determination circuit 36.
The drive signal is actually supplied to the EC element 20 by the output signal of the.

FIG. 8 shows the relationship between the duty ratio of the driving pulse (output pulse of the oscillating means 14) and the mirror reflectance by the EC anti-glare mirror driving device of FIG. Here, as in the case of FIG. 4, “H” corresponds to driving in the decoloring direction, and “L” corresponds to driving in the coloring direction. Therefore, when the duty ratio increases, the driving amount in the decoloring direction increases and the reflectance increases. When the duty ratio decreases, the driving amount in the coloring direction increases and the reflectance decreases.

According to FIG. 8, after a duty ratio e corresponding to a predetermined reflectance R% (for example, 35 to 45% is most suitable for practical use), coloring is performed in a region where the duty ratio is higher than that. The current drive circuit 34 is turned off to supply the drive current only from the EC element drive means 24, and in a region where the duty ratio is lower than e, the drive current is supplied from both the EC element drive means 24 and the coloring current variable circuit 34. Therefore, when the duty ratio is higher than e (that is, when the amount of ambient light is constant and the amount of backward light is small), the response speed of the EC element 20 to the variation of the amount of backward light becomes slow, and the reflectance frequently fluctuates. Is prevented. In addition, when the duty ratio is lower than e (that is, when the rear light amount is large).
In this case, the response speed of the EC element 20 to the fluctuation of the rear light amount is increased, and the glare can be reduced by coloring immediately when the rear of the night suddenly becomes dazzling.

Further, according to FIG. 8, in the continuously variable reflectance region from the lowest reflectance (for example, 10%) to the highest reflectance (for example, 70%), the ratio of the change of the reflectance to the duty ratio of the drive pulse is different. , The duty ratio e is changed to a boundary, and the change of the reflectance becomes gentle in the region where the duty ratio is higher than e, and the change of the reflectance becomes sharp in the region where the duty ratio is lower than e. Therefore, when the duty ratio is higher than e (that is, when the amount of ambient light is constant and the amount of backward light is small), the amount of change in the reflectance with respect to the variation of the amount of backward light is suppressed, and the trouble is eliminated. Further, when the duty ratio is lower than e (that is, when the amount of rear light is large), the amount of change in the reflectance with respect to the fluctuation of the amount of rear light becomes large, and when the night rear suddenly becomes dazzling, the reflectance becomes low. It can be greatly reduced to reduce glare.

[0018]

According to FIG. 8, e
In a region where the duty ratio is lower than that, the amount of change in the reflectance with respect to the variation in the amount of rear light is large. Further, even if the continuously variable reflectivity area is widened, it becomes narrower by the distance a-d than when the EC driving means 24 is used alone to drive.

[0019] The present invention solves the above-mentioned problems in the prior art, and prevents the reflectance from fluctuating greatly due to a slight change in light, thereby preventing the driver from feeling annoying.
Also, when the rear is suddenly dazzled by the headlights of the following vehicle at night, it is colored immediately to reduce the dazzling and to provide an auto-dimming mirror with an expanded reflectance continuously variable area. is there.

[0020]

According to the first aspect of the present invention,
Back light amount change speed detecting means for detecting the change speed of the back light amount, and drive energy supply capability for controlling the drive energy supply capability (in other words, the drive energy supply speed or drive current value) supplied from the EC element drive unit to the EC element. A variable control means is newly provided to reduce the driving energy supply capability when the backward light amount change speed is slow, and to increase the drive energy supply capability when the backward light amount speed change is fast. According to this, since the driving energy in the coloring direction is supplied suddenly when the night rear suddenly becomes dazzling, it is possible to rapidly color and reduce the dazzling immediately. In addition, when the change in the rear light amount is not abrupt, even if the rear is bright, the driving energy supply capability is reduced, so that a small change in the rear light amount is prevented from greatly changing the coloring amount, and troublesomeness is reduced. It is reduced. Also, since the coloring amount is prevented from greatly changing with respect to a slight change in the rear light amount in a region where the rear is bright,
A continuously variable reflectivity region can be secured more widely.

According to a second aspect of the present invention, there is provided an automatic anti-glare mirror in which the EC element driving means is constituted by switching means, and the amount of coloring is controlled by controlling the duty ratio of a pulse signal for driving the switching means. And means for variably controlling the driving energy supply capacity of the switching means, and variably controlling the driving energy supply capacity of the switching means in accordance with the change speed of the detected rear light amount.

According to a third aspect of the present invention, the EC element driving means is constituted by a switching element (main switching element),
In an auto-dimming mirror that controls the amount of coloring by controlling the duty ratio of the pulse signal that drives the main switching element, bypassing the current limiting element that limits the driving energy supply capability of the main switching element, An auxiliary switching element for separately supplying a driving current to the EC element is provided, and when the change speed of the detected rear light amount is slow, the operation of the auxiliary switching element is stopped and the driving current is supplied from the main switching element to reduce the rear light amount. When the change speed is fast, the drive current is supplied from both the main switching device and the auxiliary switching device to the EC device, so that the driving energy supply capability to the EC device is variably controlled according to the change speed of the rear light amount. It was done.

According to a fourth aspect of the present invention, a plurality of main switching elements connected in a push-pull manner (main switching elements for driving in a coloring direction and main switching elements for driving in a decoloring direction).
In the automatic anti-glare mirror configured as the switching means, the coloring direction driving that separately supplies the driving energy in the coloring direction to the EC element, bypassing the current limiting element that limits the driving energy supply capability of the main switching element for driving in the coloring direction. An auxiliary switching element is provided to operate the auxiliary switching element when the change speed of the detected rear light amount is fast, and to supply a driving current in the coloring direction from the main and auxiliary switching elements to the EC element. Is controlled variably in the coloring direction driving energy supply capability of the EC element according to the change speed of the EC element.

According to a fifth aspect of the present invention, in the automatic anti-glare mirror for controlling the coloring amount of the EC element by the duty ratio of the driving pulse signal, the changing speed of the duty ratio of the pulse signal is detected to detect the changing speed of the rear light amount. Is detected.

According to a sixth aspect of the present invention, a relative change speed of the rear light amount with respect to a change speed of the ambient light amount is detected as a change speed of the rear light amount.

[0026]

Embodiments of the present invention will be described below. FIG. 1 shows the outline. The ambient light amount detecting means 10 detects the amount of light around the vehicle, and is arranged, for example, in a mirror housing of an inner mirror or an outer mirror toward the front of the vehicle. Back light amount detection means 1
Numeral 2 detects the amount of light from the rear of the vehicle, and is disposed, for example, in a mirror housing toward the rear of the vehicle. The EC element 20 is formed on the front surface of the mirror reflection surface. EC
The element driving means 24 supplies driving energy to the EC element.

The coloring amount variable control means 13 controls the supply amount of the driving energy supplied from the EC element driving means 24 to the EC element 20 in accordance with the detected backward light amount and ambient light amount, and controls the coloring amount of the EC element 20. Control. That is, the amount of coloring is reduced when the amount of rear light is small, the amount of coloring is increased when the amount of rear light is large, the amount of coloring is increased when the amount of ambient light is small, and the amount of coloring is reduced when the amount of ambient light is large. The amount of driving energy supplied is controlled.

The rear light amount change speed detecting means 15 detects a change speed of the rear light amount detected by the rear light amount detecting means 12. The drive energy supply capability variable control unit 17 controls the supply capability of the drive energy supplied from the EC device drive unit 24 to the EC device 20 in accordance with the detected change speed of the rear light amount, thereby changing the coloring amount of the EC device 20. It controls the speed. That is, when the changing speed of the rear light amount is slow, the driving energy supply capability is reduced, and when the changing speed of the rear light amount is high, the driving energy supply capability is increased.

According to FIG. 1, the energy supply capacity of the EC element driving means 24 increases when the night rear suddenly becomes dazzling, and the driving energy in the coloring direction is rapidly supplied to the EC element 20. Coloring can immediately reduce glare. In addition, when the change in the rear light amount is not abrupt, even if the rear is bright, the driving energy supply capability is reduced, so that a small change in the rear light amount is prevented from greatly changing the coloring amount, and troublesomeness is reduced. It is reduced. In addition, since the coloring amount is prevented from largely changing in response to a slight change in the rear light amount in an area where the rear is bright, a continuously variable reflectance area can be secured more widely.

The rear light amount change speed detecting means 15
In addition to detecting the absolute change speed of the rear light amount, the change speed of the rear light amount relative to the change speed of the ambient light amount is considered in consideration of the change speed of the ambient light amount detected by the surrounding light amount detection means 10. It can also be detected as a change speed.

A specific example of the auto-dimming mirror shown in FIG. 1 will be described. FIG. 9 shows the outline thereof. The oscillating means 14 and the inversion cycle control means 16 constitute the coloring amount variable control means 13. The oscillating means 14 generates an oscillating signal which alternately repeats "H" level and "L" level.
The duration of the level and the duration of the “L” level are individually controllable. The oscillation period of the oscillation means 14 is desirably 10 ms or less so that the decoloring and the flickering of the coloring cannot be recognized by human eyes. The inversion cycle control means 16 variably controls the duration of one level of the oscillation signal generated from the oscillation means 14 according to the light quantity detected by the ambient light quantity detection means 10. In addition, the duration of the other level of the oscillation signal is variably controlled in accordance with the light amount detected by the rear light amount detecting means 12.

The driving power supply 22 includes the oscillation unit 14 and the E
The driving power is supplied to the C element driving means 24 and the like. The EC element driving unit 24 inverts the polarity of the driving voltage according to the level of the oscillation signal generated from the oscillation unit 14 and applies the inverted driving voltage to the EC element 20 to thereby control the amount of coloring in accordance with the duty ratio of the oscillation signal. Control.

The contents of control of the duty ratio by the inversion cycle control means 16 are as follows. That is, the EC element driving means 24 outputs the EC element 20 at one level of the oscillation signal.
Is driven in the coloring direction and the EC element 20 is driven in the decoloring direction at the other level, the inversion cycle control means 16 determines the duration of the one level when the ambient light amount is large. When the amount of ambient light is small, the duration of the one level is lengthened, and when the amount of rear light is large, the duration of the other level is shortened, and when the amount of rear light is small, the duration of the other level is reduced. Lengthen. Also,
The EC element driving means 24 outputs the E signal at one level of the oscillation signal.
When the C element 20 is set to be driven in the decoloring direction and the EC element 20 is driven in the coloring direction at the other level, the inversion cycle control means 16 sets the level of the one level when the ambient light amount is large. When the amount of ambient light is small, the duration of one level is shortened, and when the amount of rear light is large, the duration of the other level is extended, and when the amount of rear light is small, the level of the other level is reduced. Decrease duration.

By such control, the coloring amount is continuously controlled. That is, when the ambient light is dark, the sensitivity to the rear light increases, and the amount of coloring increases as the amount of the rear light increases, the reflectance decreases, and an anti-glare state is obtained. Further, when the ambient light is bright, the sensitivity to the rear light is reduced, the coloring becomes difficult, and the high reflectance is maintained.

The EC element driving means 24 comprises an EC element main driving means 25 and an EC element auxiliary driving means 27. E
The C element main driving means 25 supplies a driving current to the EC element 20 constantly. The EC element auxiliary driving means 27 is an EC element driving means for varying the coloring speed, and supplies a driving current to the EC element 20 in an auxiliary manner when the amount of light behind suddenly increases, for example, to provide a response speed (coloring speed) in the coloring direction. ). Both driving means 25 and 27 have a limitation in driving energy supply capacity (driving energy supply speed, driving current value).

The coloring speed variable control means 29 corresponds to the rear light amount change speed detecting means 15 and the driving energy supply capacity variable control means 17 in FIG. That is,
The coloring speed variable control means 29 controls the change rate of the duty ratio of the oscillation signal output from the oscillation means 14 (corresponding to the relative change speed of the rear light quantity with respect to the change rate of the ambient light quantity. Is equivalent to the difference between the duty ratios of adjacent pulses on the time axis.) When the changing speed in the direction of increasing the coloring amount is equal to or higher than a predetermined speed, the EC element auxiliary driving means 27 is operated. In a possible state, both driving means 25 and 27 are driven by the oscillation signal of the oscillating means 14, and the EC elements 2 are output from both driving means 25 and 27.
0 is supplied with a driving current in the coloring direction. As a result, the response speed is increased, and when the rear suddenly becomes dazzling at night or the like, coloring is rapidly performed, and glare can be reduced. When the changing speed in the direction of increasing the coloring amount is equal to or lower than a predetermined speed, or when the duty ratio is not changing, or when the duty ratio is changing in the direction of decreasing the coloring amount, the EC element auxiliary driving means is used. 27 is made inoperable, and a driving current in the coloring direction or the decoloring direction is supplied to the EC element 20 only from the EC element main driving means 25. As a result, the ability to supply the driving energy is reduced, the response speed is reduced, and the coloring amount is prevented from greatly changing with a slight change in the rear light amount, and the trouble is reduced.
In addition, a continuously variable reflectivity area is ensured.

FIG. 10 shows a detailed configuration of the configuration shown in FIG. Common parts are used for parts corresponding to the respective parts in FIG. The driving power supply 22 receives the +12 V DC voltage from the battery, converts it into a positive power supply circuit 26 (coloring direction driving voltage generation means), converts it to about +1.6 V DC voltage, and supplies the negative power supply circuit 28 (color erasing direction driving voltage generation). Means) to convert it to a DC voltage of about -1.6V. If these positive and negative power supply circuits 26 and 28 are constituted by switching power supplies, the efficiency is high, the space is not taken up even when built in the mirror housing, and the heat generation is small.

The oscillating means 14 has an inversion cycle control means 16 in its feedback loop. Inversion cycle control means 16
Are the coloring-side pulse generator 16a and the decoloring-side pulse generator 1
6b. The coloring side pulse generator 16a
CdS10 constituting ambient light detecting means, and CdS1
0, a resistor R1 and a diode D1 connected in series.
And a resistor R2 connected in parallel to CdS10. The decoloring-side pulse generating section 16b is composed of CdS12 constituting the rear light detecting means, a resistor R3 and a diode D2 connected in series to the CdS12, and a resistor R4 connected in parallel to the CdS12.

Since CdS has characteristics close to the visible light range of the human eye, CdS is optimal as a photoconductive cell used for ambient light detecting means and rear light detecting means. CdS has a characteristic that the resistance value decreases as the light amount increases, and the resistance value increases as the light amount decreases. Therefore, in the oscillation signal output from the oscillation means 14, as shown in FIG. 4, the period t1 of the "H" level changes according to the rear light amount (it becomes shorter as it becomes brighter), and the period of the "L" level. t2 changes according to the amount of ambient light (it becomes shorter as it becomes brighter). When the ambient light amount is equal to the rear light amount, t1 = t2 as shown in FIG. 11A, and when the ambient light amount is smaller than the rear light amount, t1 <t2 as shown in FIG. 11B. t2, and when the amount of ambient light is larger than the amount of rear light, FIG.
As shown in (c), t1> t2. As described below,
The EC element 20 is supplied with the decoloring energy in the period t1 and the coloring energy in the period t2.
<T2 has a coloring tendency, and t1> t2 has a decoloring tendency.

In FIG. 10, the "H" level is about +1.6 V and the "L" level is about -1.
An oscillation signal of 6 V is output. The capacitor C4 is a bypass capacitor for preventing generation of noise in the power supply line. The EC element driving means 24 includes two switching transistors Q1 and Q2 (main switching elements for driving in the coloring direction and for driving in the decoloring direction) that are complementary and push-pull connected between the positive and negative power supply voltages of about ± 1.6 V. I have. The resistors R6 and R7 are connected in series between the power supply line of about +1.6 V and the output terminal of the oscillation unit 14, and the resistors R6 and R7 are connected in series.
The voltage at the connection point of R7 is applied to the base of transistor Q1. Further, resistors R8 and R9 are connected in series between the power supply line of about -1.6 V and the output terminal of the oscillating means 14, and the voltage at the connection point of the resistors R8 and R9 is applied to the base of the transistor Q2. ing. With such a configuration, when the output of the oscillating means 14 is at "H" level, the transistor Q1 is turned off, the transistor Q2 is turned on, and E
The energy in the decoloring direction is supplied to the C element 20. Also,
When the output of the oscillating means 14 is at the "L" level, the transistor Q1 is turned on and the transistor Q2 is turned off, and the energy in the coloring direction is supplied to the EC element 20. Here, since the resistors R10 and R11 are connected in series as the energy supply capacity limiting element (main drive current limiting element) to the transistors Q1 and Q2, the energy supply (current supply) ability in the coloring direction and the decoloring direction is performed. And power consumption and heat generation in the EC element 20 are suppressed. Also, EC
Since the element 20 is electrically the same as the capacitor, the resistance R1
0 or R11 to form a time constant circuit (R1
0 and R11 are about 5Ω, for example), and the response speed of coloring and decoloring is reduced.

The coloring speed variable control means 29 includes the oscillation means 1
4 is input, and the pulse signal is inverted by the inverter 40. Therefore, the output signal of the inverter 40 has a large duty ratio when the EC element 20 is driven in the coloring direction, and has a small duty ratio when driven in the decoloring direction. A series circuit of a resistor R26 and a diode D3 is connected between the +1.6 V power supply line and the output terminal of the inverter 40. Diode D3
Is connected to resistors R27 and R29 and a capacitor C2.
Is connected to the -1.6 V power supply line. The cathode of the diode D3 is a resistor R30 and a capacitor C
3 is connected to a -1.6 V power supply line. The resistors R27 and R28 are connected between both ends of the diode D3. The voltages at the upper terminals of the capacitors C2 and C3 are input to the inverting input terminal and the non-inverting input terminal of the comparator 42, respectively. Where R29
= R30 >> R28, C2> C3.

According to the above configuration, in a steady state (when there is no change in the duty ratio of the pulse signal output from the oscillating means 14), the forward voltage of the diode D3 (approximately 0.6
The voltage Vo obtained by dividing V) by the resistors R27 and R28 is input to both input terminals of the comparator 42. Therefore, at this time the voltage V at the inverting input terminal of the comparator 42 _- because who is higher than the non-inverting V _+, the output of the comparator 42 is at the "L" level (Fig. 12). Further, when (when the change is gradual) there is a change in the duty ratio of the pulse signal but changing rate is small V _-, voltage V ₊ is V _-> V ₊
, The output of the comparator 42 remains unchanged at the "L" level (FIG. 13).

On the other hand, when the rear suddenly becomes dazzling at night, the duty ratio of the output signal of the inverter 40 rapidly increases, so that the capacitors C2 and C3 start charging in the + direction. Here, R29 = R30 >> R2
8, C2> C3 because it is set in, towards the _{V +} is V _-
And the output of the comparator 42 becomes "H"
Depending on the level (FIG. 14). Then V _- is also increased with a delay, and changes in the duty ratio becomes smaller, V _- of it is V
₊ , The output of the comparator 42 becomes “L”
Return to level. When returning to the steady state, the potential difference Vo across the resistor R28 is applied to both input terminals of the comparator 42,
The output of the comparator 42 is kept at "L" level.
FIG. 15 shows an operation when the duty ratio of the output signal of the inverter 40 increases more rapidly. When the duty ratio of the output signal of the inverter 40 decreases (when the rear becomes darker or the surroundings become brighter), V ₋ > V ₊ is always satisfied regardless of the speed of the change. Output remains at "L" level (FIG. 16).

In the EC element auxiliary driving means 27, +
Resistors R15 and R16 are connected in series between the 1.6V power supply line and the output terminal of the oscillating means 14, and a resistor R1
The collector of the transistor Q3 and the base of the transistor Q4 are connected to the connection point of R5 and R16. The transistor Q4 has an emitter connected to a power supply line of +1.6 V, and a collector connected via a current limiting resistor R17 to the EC.
Connected to element 20. Therefore, the transistor Q4 and the transistor Q1 are arranged in parallel between the + 1.6V power supply line and the EC element 20, and both of them are E
A driving current in the coloring direction is supplied to the C element 20.

The operation of the EC element driving means 24 will be described.
When the night rear suddenly becomes bright, the output of the comparator 42 becomes "H", and the transistor Q3 is opened. Therefore, the transistor Q4 repeatedly turns on and off simultaneously with the transistor Q1 by the output pulse of the oscillation means 14, and supplies a coloring current to the EC element 20 together with the transistor Q1. Therefore, at this time EC
The current value of the drive pulse of the element 20 increases, and the coloring response speed increases. Thereby, the amount of coloring is immediately increased to reduce glare.

When the changing speed of the backward light quantity is slow, the output of the comparator 42 becomes "L", so that the transistor Q3
Is turned on, the transistor Q4 is in a halt state, and no driving current is supplied from the EC element auxiliary driving means 27. Therefore, at this time, the current value of the drive pulse of the EC element 20 becomes small, and the response speed becomes slow. This prevents frequent repetition of coloring and decoloring due to slight light fluctuations. In addition, a continuously variable reflectivity area is ensured.

Here, the circuit of FIG. 10 and the case where the EC element auxiliary driving means 27 and the coloring speed variable control means 29 are not provided in the circuit of FIG. 10 (Japanese Patent Application No. 6-99291).
The following describes the difference between the operation of the first embodiment and that of the first embodiment. Now, it is assumed that the relationship between the duty ratio of the output pulse of the oscillation means 14 and the mirror reflectance is as shown in FIG. The relationship between the time when the duty ratio changes from 45% to 25% and the time when the reflectance changes from 60% to 25% is as shown in Table 1 when the EC element is not auxiliary-driven. become.

(Table 1) Time during which the duty ratio changes (seconds) 5 4 3 2 1 Time during which the reflectivity of the mirror changes (seconds) 5 4 3.2 2.8 2.7 When this is graphed, it becomes as shown by a dashed line in FIG. In this example, when the change time of the duty ratio is 3 seconds or more, the reflectance of the mirror can follow this, but when it is 3 seconds or less, it cannot follow.

On the other hand, when the circuit of FIG. 10 was measured in the same manner, the result was as shown by the solid line in FIG. 18, and the response of the change in the reflectance when the duty ratio changed suddenly was enhanced.

Further, the case where the EC element auxiliary driving means is controlled in accordance with the changing speed of the rear light amount (the present invention) and the case where the EC element auxiliary driving means is controlled in accordance with the rear light amount itself (Japanese Patent Application No. 6-301322). 8, the relationship between the duty ratio and the reflectance in the case where the control is performed according to the rear light amount is as shown by the solid line in FIG. 8, and the change between de is always steep. Therefore, the continuously variable reflectivity region is between db. On the other hand, in the circuit of FIG. 10, if the change speed of the duty ratio is small, the EC element auxiliary driving means 27 does not operate regardless of the magnitude of the duty ratio. It has become wide.

[0051]

As described above, according to the present invention, when the rear portion at night becomes suddenly dazzling, the driving energy in the coloring direction is rapidly supplied, so that the coloring is rapidly performed, and the dazzling is immediately reduced. be able to. In addition, when the change in the rear light amount is not abrupt, even if the rear is bright, the driving energy supply capability is reduced, so that a small change in the rear light amount is prevented from greatly changing the coloring amount, and troublesomeness is reduced. It is reduced. In addition, since the coloring amount is prevented from largely changing in response to a slight change in the rear light amount in an area where the rear is bright, a continuously variable reflectance area can be secured more widely.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional device.

FIG. 3 is a circuit diagram showing a specific example of an EC element driving unit 24 of FIG. 2;

FIG. 4 is a waveform diagram showing an oscillation output of the oscillation means 14 of FIGS. 2, 7, 9, and 10;

5 is a diagram showing a change characteristic of a mirror reflectance with respect to a duty ratio of the conventional device of FIG. 2 according to the oscillation output of FIG. 4;

FIG. 6 is a diagram showing a change in mirror reflectance characteristics due to resistors R10 and R11 in FIG. 3;

FIG. 7 is a block diagram showing another conventional device obtained by improving the conventional device of FIG. 2;

8 is a diagram showing a change characteristic of a mirror reflectance with respect to a duty ratio of the device of FIG. 7 according to the oscillation output of FIG. 4;

FIG. 9 is a block diagram showing a specific example of FIG. 1;

FIG. 10 is a circuit diagram showing a detailed configuration of FIG. 9;

11 is a waveform diagram showing a change in the oscillation output of the oscillating means of FIG. 10 depending on the amount of ambient light and the amount of rear light.

FIG. 12 is a waveform chart showing an input / output relationship (steady state) of the comparator 42 in FIG.

13 is a waveform diagram showing the input / output relationship of the comparator 42 in FIG. 10 (when the rear gradually becomes brighter).

14 is a waveform diagram showing an input / output relationship of the comparator 42 in FIG. 10 (when the rear is suddenly dazzling).

FIG. 15 is a waveform diagram showing an input / output relationship of the comparator 42 in FIG. 10 (when the rear is more suddenly dazzling).

FIG. 16 is a waveform diagram showing an input / output relationship of the comparator 42 in FIG. 10 (when the rear becomes dark).

17 is a diagram illustrating an example of a relationship between a duty ratio of a pulse signal output from the oscillation unit 14 of FIG. 10 and a mirror reflectance.

FIG. 18 is a diagram illustrating an example of the relationship between the change time of the duty ratio and the change time of the reflectance.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Ambient light amount detecting means, CdS 12 Back light amount detecting means, CdS 13 Coloring amount variable control means 14 Oscillating means, pulse signal generating means 15 Back light amount change speed detecting means 17 Driving energy supply capability variable control means 20 EC element 24 EC element driving Means, EC element switching drive means 25 EC element main drive means 26 Positive power supply circuit (coloring direction drive voltage generating means) 28 Negative power supply circuit (color erasing direction drive voltage generating means) 29 Coloring speed variable control means (backward light amount change speed detection) Means, coloring direction driving energy supply capability variable control means) Q1 main switching element for driving in the color direction Q2 main switching element for driving in the decoloring direction Q4 auxiliary switching element for driving in the coloring direction R10, R11 main driving current limiting element R17 auxiliary driving current limiting element

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-136555 (JP, A) JP-A-7-281212 (JP, A) JP-A-6-281967 (JP, A) JP-A 63-281 192027 (JP, A) JP-A-62-299903 (JP, A) JP-A-62-1652 (JP, A) JP-A-61-156030 (JP, A) Japanese Utility Model Laid-Open No. 6-75906 (JP, U) Japanese Utility Model Application Hei 6-69941 (JP, U) Japanese Utility Model Application Hei 1-172027 (JP, U) Japanese Utility Model Application Showa 60-28538 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60R 1/04

Claims (6)

(57) [Claims] 1. An automatic anti-glare mirror having a variable reflectivity by an EC element, a rear light amount detecting means for detecting a rear light amount of a vehicle, and a rear side for detecting a change speed of the detected rear light amount. A light amount change speed detecting unit; an ambient light amount detecting unit for detecting an ambient light amount of a vehicle; an EC element driving unit for supplying driving energy to the EC element;
The amount of coloring of the EC element is controlled by controlling the amount of driving energy supplied from the C element driving means to the EC element. When the amount of rear light is small, the amount of coloring is reduced, and the amount of rear light is large. When the amount of coloring is large, when the amount of ambient light is small, the amount of coloring is large, and when the amount of ambient light is large, the amount of coloring is variable. Controlling the supply capability of the driving energy supplied from the EC element driving means to the EC element in accordance with the changing speed of the rear light amount to control the changing speed of the coloring amount of the EC element. When the changing speed of the rear light quantity is low, the driving energy supply capability variable control means for reducing the driving energy supply capability is used. Automatic anti-glare mirror provided. 2. An automatic anti-glare mirror having a variable reflectivity by an EC element, a rear light amount detecting means for detecting a rear light amount of a vehicle, and a rear side for detecting a change speed of the detected rear light amount. A light amount change speed detecting unit, an ambient light amount detecting unit for detecting an ambient light amount of the vehicle, and a driving power supply for the EC element is switched to perform the EC operation.
EC element switching driving means for supplying driving energy to the element, and a pulse signal for driving the EC element switching driving means, wherein one of the "H" level and the "L" level of the pulse signal Supplying the energy for driving the EC element in the coloring direction during the period, and driving the EC element switching drive unit to supply the energy for driving the EC element in the decoloring direction during the other level, and The duty ratio of the pulse signal is controlled in accordance with the detected rear light amount and the ambient light amount. When the rear light amount is small, the period of the one level is relatively shortened. The period of one level is relatively long, and when the amount of ambient light is small, the period of the one level is relatively long. A pulse signal generating means for relatively shortening the one level period, and a supply capability of driving energy supplied from the EC element switching driving means to the EC element in accordance with a change speed of the detected rear light amount. And controlling the changing speed of the coloring amount of the EC element. When the changing speed of the rear light amount is slow, the driving energy supply capacity is reduced. When the changing speed of the rear light amount is fast, the driving energy is controlled. An anti-glare mirror comprising: a drive energy supply capability variable control means for increasing the supply capability of the mirror. 3. The EC element switching drive means is turned on and off by the pulse signal, and
A main switching element that supplies a driving current to the element, a main driving current limiting element that is inserted into a supply path of the driving current to the EC element by the main switching element and limits a driving current value, and the pulse signal. An auxiliary switching element that is turned on and off and supplies a separate drive current to the EC element, bypassing the main drive current limiting element; When the change speed of the light quantity is slow, the operation of the auxiliary switching element is stopped to supply a drive current from the main switching element to the EC element, and when the change rate of the rear light quantity is fast, the auxiliary switching element is made operable. 3. A driving current is supplied to the EC element from both the main switching element and the auxiliary switching element. Automatic anti-glare mirror. 4. An automatic anti-glare mirror having a variable reflectivity by an EC element, comprising: a rear light amount detecting means for detecting a rear light amount of a vehicle; and a rear side for detecting a change speed of the detected rear light amount. Light amount change speed detecting means, ambient light amount detecting means for detecting the ambient light amount of the vehicle, coloring direction drive voltage generating means for generating a coloring direction drive voltage for driving the EC element in a coloring direction, and decoloring the EC element A decoloring direction voltage generating means for generating a decoloring direction driving voltage for driving in the direction, a coloring direction driving main switching element for switching the coloring direction driving voltage and supplying a driving current in the coloring direction to the EC element; A main switching element for driving the decoloring direction for switching the decoloring direction driving voltage and supplying a driving current in the decoloring direction to the EC element; A main drive current limiting element that is inserted into a supply path of a drive current to the EC element by a child to limit the drive current value, and that generates a pulse signal for driving each of the main switching drive means, The coloring direction driving main switching element is turned on and the decoloring direction driving main switching element is turned off at one of the “H” level and the “L” level of the pulse signal, and the coloring direction is turned at the other level. The main switching element for driving is turned off and the main switching element for driving in the decoloring direction is turned on, and the duty ratio of the pulse signal is controlled according to the detected rear light amount and ambient light amount, and the rear light amount is controlled. When the amount of light is small, the period of the one level is relatively short, when the amount of rear light is large, the period of the one level is relatively long, and when the amount of ambient light is small, A pulse signal generating means for relatively lengthening the period of one level and relatively shortening the period of the one level when the amount of ambient light is large; and turning on the one level of the pulse signal to turn on the other level. And a coloring direction driving auxiliary switching element for supplying a driving current in a coloring direction to the EC element by bypassing the main driving current control element, and when the change speed of the detected backward light quantity is low. Stops the operation of the coloring-direction driving auxiliary switching element and supplies a driving current in the coloring direction from the coloring-direction driving main switching element to the EC element. Activating the auxiliary switching element for the color direction and the EC element from both the main switching element for driving the coloring direction and the auxiliary switching element for driving the coloring direction. Auto-dimming mirror formed by and a coloring direction driving energy supply capacity variable control means for supplying the coloring direction of the drive current. 5. The method according to claim 2, wherein said rear light amount change speed detecting means detects a rear light amount change speed from a change speed of a duty ratio of said pulse signal generated from said pulse signal generating means. The auto-dimming mirror as described. 6. The rear light quantity change speed detecting means detects a relative change speed of the rear light quantity with respect to a change rate of the ambient light quantity as the change rate of the rear light quantity.
6. The automatic anti-glare mirror according to any one of claims 1 to 5.