SK9352001A3 - Vehicle rearview system with electrochrome mirror - Google Patents

Abstract

The invention relates to a vehicle rearview system (1) comprising at least one rearview mirror unit fitted with an electrochrome mirror (2), a control device and a vehicle voltage supply device. The control device is electrically connected to the vehicle voltage supply device for its voltage supply and to the electrochrome mirror so as to control the reflection characteristics of said mirror in accordance with a control voltage. The control device comprises a flat heating resistor (3) to dissipate the heat resulting from electric power loss.

Description

Rearview system with electrochromic mirror for vehicles

Technical field

The invention relates to a rear vision system for vehicles. In particular, the invention relates to a vehicle vision system according to the preamble of claim 1.

BACKGROUND OF THE INVENTION

Rear-view systems for vehicles are known in which at least one rear-view mirror is equipped with an electrochromic mirror and further comprising a control device and an electrical system of the vehicle. The control device is connected to the electrical system of the vehicle from which it draws energy for its own operation, and to an electrochromic mirror whose reflection properties control the control voltage, which is dependent on the intensity of the incident light. Adjustment of the electrochromic mirror to the required level of reflectance or transmittance is effected by a DC control voltage generated by the control device based on information from the light sensors. The control voltage varies between 0 V and about 1.2 V. The main parts of the control device are mostly built into the rear-view mirror housing in the interior of the vehicle (interior mirror). As a rule, all mirrors on the vehicle are fitted with an electrochromic mirror, i. outside mirror and outside mirrors (outside mirrors). The low control voltage is used to match the interior and exterior mirrors.

However, problems arise from the fact that the electrical system of normal passenger cars operates at a voltage typically between 9 and 16 V (usually at a nominal voltage of 12 V), while the maximum control voltage level is only 1.2 V, for example. of an electrochromic mirror is about 300 mA, which means that about 4 W of electrical energy must be converted into heat without benefit. In prior art devices

· · · · · · · · • • • · • · • • • · · • · • • • · · • · • · • · • · • • · • · • • • • • • • • · · · ···· · · · · ·· ·

this conversion takes place in a power transistor that is built into the tight interior mirror housing. An aluminum heatsink is used to cool the transistor.

With the continued miniaturization of components and circuits, heat dissipation proves to be quite problematic. In the current state of the art, it is no problem to integrate all components and circuits for controlling an electrochromic mirror into a single power semiconductor integrated circuit (power 10). However, the power 10 would have to be able to dissipate the aforementioned 4 W heat dissipation into the environment so that the temperature of the chip itself does not exceed a critical temperature of about 125 ° C. This would require, in addition to the expensive own housing of the power 10, a sufficient volume of sufficiently cool air to surround the 10. However, this meets the limited dimensions of the interior mirror housing and, moreover, such a requirement goes directly against the intended miniaturization of the device. For exterior mirrors, the solution can be even more difficult: not only does the available space tend to be smaller than the interior mirror, but it is also necessary to heat the exterior mirror cover, for example, by sunlight during summer days.

It is an object of the invention to provide a vehicle vision system in which the control device can be integrated into a small space, but the heat dissipation will not impair the operation of the control electronic system.

SUMMARY OF THE INVENTION

Said object of the invention is achieved by a rear vision system for vehicles having the features of the preamble of the main claim in conjunction with the features of the feature of the feature.

According to the invention, the control device is fitted with a surface heating resistor (heating resistor) in which the excess electrical energy is converted into heat, which is dissipated outside the control electronics so as to adversely affect it. · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · The heat generated in the sheet heating resistor can be introduced to a location where it may be useful, for example to the surface of the mirror.

Further advantageous embodiments of the invention are set out in the dependent claims.

In a preferred embodiment of the invention, the heating resistor is applied in the form of a coating to a carrier material, for example a non-reflective rear side of the rear-view mirror. The support material may be in the form of a resilient sheet or a flat electrical conductor. The coating can be applied to a variety of flat materials. The heat generated does not affect the operation of the control electronics and can moreover be advantageously used, for example, to prevent the objects from fogging and / or freezing.

In a particularly preferred embodiment, the heating resistor is in the form of a conductor placed meanderingly on a carrier material, preferably a plastic film. An additional meander-shaped mirror glass heating system can be attached to the same plastic sheet. Both resistors may lie side by side or overlap. The foil can be provided with adhesive tape on both sides and glued with one side to the back of the mirror and the other side to the backing plate of the mirror. In addition to the good conduction of heat to the mirror to be heated, this embodiment is also advantageous in view of the easy and inexpensive connection of the mirror to the support plate.

In another preferred embodiment of the invention, the control device has a pulse width modulation (PWM) modulation control unit at a level that is preferably a voltage level of the vehicle electrical system. The width modulation unit is coupled to a transducer which belongs to the control unit and converts the width modulated signal to an analog control voltage. If the signal level coincides with the voltage level of the vehicle electrical system, it is preferable to direct the signal generated in the signal generator located in the interior mirror housing to the exterior mirrors. The transducer according to the invention is placed in an external mirror where the pulse-modulated signal with the vehicle voltage is converted into a low analogue control voltage in the heating resistor according to the invention. This saves the earthed wire drawn

· · · · · · · · · · • • · • · • · • • • · · · * · • • · · · • · • • · • • · · • • · • · • • · • • · • • • · • · · ···· · · · · · · · ·

between interior and exterior mirrors, which is necessary in the prior art to equalize the potential difference between the interior and exterior of the vehicle. In a preferred embodiment of the invention, when the signal to the exterior mirrors is supplied at the voltage level (about 12 V) of the vehicle electrical system, the differences from the prior art embodiments operating at low signal levels (about 1.2 V) are virtually insignificant.

Further advantageous embodiments of the invention are described in the remaining dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail with reference to the accompanying drawings, in which:

In FIG. 1 is a heating resistor according to the invention located on the back of an electrochromic mirror;

In FIG. 2 is a cross-sectional view of an exterior mirror according to the invention;

In FIG. 3 is a block diagram of a vision system of the invention;

In FIG. 4a and 4b are two possible methods for connecting the heating resistor according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, there is shown a shrinkage resistor for heat dissipation, a heating resistor 3 according to the invention. The resistor is in the form of a meander-wound conductor fixed to the non-reflective rear side 2a of the electrochromic mirror 2 of the rear-view mirror. On the rear side 2a of the mirror, the resistance can be applied, for example, by means of a plasma arc as a metal coating, by pressing with a resistive paste (paste is applied to the place of future resistance) or by electroplating. Heating resistance

· · · · • · · · · · • · • · • • • · • · · in • • • • · · • · • · • • · • • • • · · • • • • · • • • · · · ···· · · · · ·· ·

(i.e., a coating) may be copper, silver or aluminum. In all cases, the shape of the heating resistor 1 consists of lines or strips and the voltage in the resistance decreases between the electrical terminals 3a and 3b. which represent the beginning and the end of the heating resistor 3.

In a similar manner, the mirror heating system 6 is attached to the rear side 2a of the electrochromic mirror 2. The heating system 6 also heats the mirror 2. The system 6 may also have a meander shape. It is preferred that the line of the heating system 6 complements the line of the heating resistor 3 as shown in FIG. First

It is not absolutely necessary for the heating resistor 3 to adhere directly to the electrochromic mirror 2. Although it is advantageous to use the heat of dissipation of the resistor to heat the mirror, it prevents fogging and freezing, but other arrangements are possible. For example, it is possible to apply a heating resistor 3 to the printed circuit board (flex or FPC supply lines). For example, these supply lines can provide an electrical connection between the control device and the electrochromic mirror or connect the individual elements of the control device (see Fig. 3).

In FIG. 2 is a cross-sectional view of an exterior rear-view mirror according to the invention, or an exterior mirror unit 5. This has an electrochromic mirror 2, which is electrically connected to a control device in a manner not shown in more detail. The control device or parts thereof (see Fig. 3) can be housed in the housing 9 of the exterior mirror unit 5 (Fig. 2 shows only the heating resistor 3 associated with the control device located inside the housing 9).

The cover 9 is connected to the vehicle body 18 by an arm 19. The adjusting mechanism 8, which is located inside the housing 9, carries the support plate 7. On the side of the support plate 7 which faces away from the adjusting mechanism 8, a heating resistor 3 according to the invention is fastened. The heating resistor is terminals 3a and

3b is connected to other not shown elements of the control device. The electrochromic mirror 2 adjoins that side of the heating resistor 3, which is spaced from the carrier plate 7. Fixing the heating resistor 3 between the carrier

9

9

99

The 9999 plate 7 and the electrochromic mirror 2 can be made in various ways. For example, the heating resistor 3 can be applied to the back side 2a of the mirror in the form of a metal coating.

Another possibility is to make the heating resistor 3 as a foil composite. A resistive element that extends between contacts 3a and 3b. is sealed between two foils. The resulting composite of precise shape can then be attached, for example, by elastic clips, to the rear side 2a of the electrochromic mirror. In another embodiment, the outer sides of both sheets may be self-adhesive. In this case, the heating resistor 3 actually provides a firm connection between the mirror 2 and the support plate 7 (an alternative to the self-adhesive film is to use double-sided adhesive tape on both outer sides of the composite - the result is probably the same).

Of course, other elements of the control device can also be mounted between the support plate 7 and the mirror 2, e.g. integrated circuit. Such an integrated circuit may be applied directly to the back side 2a of the mirror 2 or to a film by surface mount (SMD) or chip on board integration. The integrated circuit may also be sealed into the film composite as described above. Heat-resistant materials are preferably used as films.

Other elements of the control device, such as a digital-to-analog converter, can also be housed in the housing 9 of the exterior mirror unit 5, for example inside the adjusting mechanism 8.

The embodiments of FIG. 1 and 2 refer to the exterior mirror, but can be used equally well for the interior mirror.

In FIG. 3 is a schematic representation of a vehicle rearview system. The system comprises two rear-view mirror units - an interior mirror unit 4 and an exterior mirror unit 5. The vehicle electrical system (not shown) provides a 12 V DC power supply, but may vary between 5 V and 24 V depending on the vehicle. the unit is connected to the vehicle power system. The exterior mirror unit 5 has one or two electrochromic mirrors (one on each side of the vehicle), the interior mirror unit 4 has one electrochromic mirror.

· · · · · · · · · · • · • · • · • • • · • • · • • · · · • · • · • · • · • • • · · • · • • · • • e · · · ···· · · · · · · •

The glare sensor 10, which is fixed to the interior mirror and oriented in the direction of reflection of the electrochromic mirror (i.e., rearward), measures the intensity of the incident light coming from the rear of the vehicle (e.g. from other vehicles behind the vehicle in which the device is installed). The daylight sensor 11, which is oriented forward or sideways, determines the intensity of the additional light. The sensors 10 and 11 are coupled to the processing unit 20 of the data transfer control device. Based on the values detected by the sensors, the processing unit 20 calculates the glare value that is converted to an analog control signal.

The analog control signal is then applied to the transistor (see input 17a of transistor O in Figures 4a and 4b). The circuit of FIG. 4a and 4b. which will be explained in more detail below, generates a DC voltage between 0 and 1.5 V corresponding to the glare intensity, which is then fed to an electrochromic mirror

2. Depending on this voltage, the reflective properties of the electrochromic mirror 2 vary in a known manner. The analog signal 21 has a voltage of, for example, between 0 and 1.5 V, but may, depending on the particular embodiment, be higher, for example between 0 and 2.5 V.

In addition to controlling the reflective properties of the inner mirror, the processing unit 20 also controls the reflective properties of the at least one electrochromic mirror 2 of the outer mirror unit 5. The processing unit 20 transmits an analog signal such as applied to the electrochromic mirror 2 of the inner mirror unit 4 5. This signal may, for example, be transmitted directly. Another possible transmission method is shown in FIG. Third

This alternative is to digitize the analog control signal in the analog-to-digital converter 15, which may be located, for example, in the vehicle roof module (in some embodiments of the processing unit 20, the embedded microprocessor may transmit a digital signal directly). The digitized signal from the analog-to-digital converter 15 is routed via a data bus to the door control device 12- The door control device 12 is a node to which all the control functions of the vehicle door elements such as the drives converge. ··· ············································································· · Windows, mirror heating, mirror actuators, lighting and signaling equipment.

The connection between the door control device 12 and the unit 14 is another possible variant of transmitting the control signal to the electrochromic mirror 2.

The door control device 12 comprises a control unit for gravelly modulating the control signal at a level which corresponds to the voltage of the vehicle electrical system (other than the normally used 12 V, of course, it may be another voltage). The pulse width modulated brightness signal is fed to the unit 14 at the vehicle voltage level. The unit 14 has a transducer which converts the pulse width modulated signal 13 to an analog control voltage. In order to avoid the above-mentioned problems of releasing excess energy in the form of heat, the transmission must take place in the circuit shown in FIG. 4a or 4b. An analog control voltage of 0 to 1.5 V is then applied to an electrochromic mirror 2.

In the exemplary embodiment described, the processing unit 20 is located in the inner mirror unit. It is, of course, also possible to place it in the exterior mirror unit 5. In the embodiment according to the invention, with the heating resistance, there are no problems with the possible overheating of the exterior mirror, and in addition the generated heat can also be used to heat the mirror surface. The processing unit may also be located elsewhere, for example in the area of the door control device 12 or in the roof module.

The exemplary embodiment of FIG. 3 thus shows three possible ways of transmitting the signal from the processing unit 20 to the electrochromic mirror 2:

1. analogue transmission;

2. digitization and transmission of digital signal by data bus;

3. Pulse width modulated signal transmission with a level corresponding, for example, to the voltage of the vehicle electrical system.

Only one of the above or a combination thereof may be used in the vehicle for signal transmission. In the case of digital transmission after data collection ······················································· A digital-to-analog converter is required to convert a digital signal to an analogue control voltage, preferably a UART or CAN protocol.

In FIG. 4a shows a wiring diagram that minimizes heat generation in the region of transistor Q. The surface heating resistor 2 is connected in series with the parallel connection of the control transistor O and the electrochromic mirror 2. Between points 23 and 24 is the voltage of the vehicle electrical system. A control voltage or control signal is applied to the transistor via input 17a to adjust the current through the transistor and resistor. Depending on this transient current, a certain voltage is set at the heating resistor R. The difference between the vehicle electrical system voltage and the voltage drop across resistor R remains on the electrochromic mirror 2 and should be within the range of 0 to 1.5 V. The circuit of FIG. 4a is particularly advantageous in that the transistor Q is not thermally loaded. Instead of the aforementioned 4 W heat of the prior art, with the connection according to the invention a maximum of 0.5 W.

In FIG. 4b is an alternative embodiment of the circuitry of the invention. Between points 23 and 24 there is again a voltage of, for example, 12 V (voltage of the vehicle electrical system). In this embodiment, the transistor Q, which is controlled by the control signal 17a, the heating resistor 3 and the electrochromic mirror 2 are connected in series. As in the embodiment shown in FIG. 4a, there is also a heating resistor of a flat, spiral or meander shape.

The circuits of FIG. 4a and 4b are designed such that the maximum control voltage on the electrochromic mirror is less than 25% of the nominal voltage of the vehicle electrical system.

Claims (22)

PATENT CLAIMS f DIMENSION ‘· · · · · · · ·‘ ‘‘ ‘f f f f f f f f Vehicle rearview system (1) comprising at least one rear-view mirror unit equipped with an electrochromic mirror (2), a control device and a vehicle electrical system, the steering equipment being electrically connected to the vehicle electrical system from which it is powered , with an electrochromic mirror for controlling its reflection properties with a control voltage, and with a surface heating resistor, characterized in that the control device has, as a collision resistance, a surface heating resistor (3) for dissipating the heat dissipation energy generated when generating the control voltage. Vehicle rear vision system according to claim 1, characterized in that the control voltage is less than 25% of the voltage of the vehicle electrical system. Vehicle rear view system according to claim 1 or 2, characterized in that the rear-view mirror unit is designed as an inner mirror unit (4) or an outer mirror unit (5). Vehicle rearview system according to claim 3, characterized in that both the inner mirror unit (4) and the outer mirror unit (5) have electrochromic mirrors (2) which are connected to the control device. Vehicle rearview system according to claim 3, characterized in that the parts of the control device are located in the housing (9) of the inner mirror unit (4) or the outer mirror unit (5). ····················································· Vehicle rear vision system according to one of Claims 1 to 5, characterized in that the heating resistance (3) is applied as a coating to the carrier material. Vehicle rear view system according to claim 6, characterized in that the carrier material is a non-reflective rear side (2a) of the rear view mirror unit mirror (2), a flat electric conductor or a foil. Vehicle rear vision system according to claim 6, characterized in that the coating is of copper, silver or aluminum. Vehicle rear vision system according to claim 7, characterized in that the heating resistor (3) is mounted on the carrier material (2) in a meandering shape. Vehicle rear view system according to claim 9, characterized in that the same support material (2) on which the heating resistor (3) is arranged in a meandering shape also houses a mirror heating system (6) corresponding to the return unit. mirror. Rear vision system according to one of Claims 1 to 10, characterized in that the heating resistor (3) is connected to the electrochromic mirror (2) either as part of it or in a form-fitting manner. ·························· Vehicle rear view system according to one of Claims 1 to 11, characterized in that the mirror is mounted on the rear-view mirror unit of the respective carrier plate (7), the plate is oriented towards the non-reflective rear side of the mirror and the heating resistance (3) is as well as other elements of the control device located between the mirror and the support plate. Vehicle rear view system according to one of Claims 1 to 12, characterized in that the elements of the control device are mounted in an adjustment mechanism (8) corresponding to the rear-view mirror unit. Vehicle rear vision system according to one of claims 1 to 13, characterized in that the control device comprises an integrated circuit. Vehicle rearview system according to claim 14, characterized in that the integrated circuit is applied directly to the film. Vehicle rearview system according to one of Claims 1 to 15, characterized in that the control device comprises at least one light sensor (10, 11) which is positioned in the area illuminated by the light which strikes the electrochromic mirror and which generates a control signal for generating a control voltage depending on the intensity of the incident light. Vehicle vision system according to one of Claims 1 to 16, characterized in that the control device comprises a pulse width modulation control unit (12) at the voltage level of the electrical system of the vehicle, the pulse width modulation unit being connected to a transformer. ····················································· Rom (14), which belongs to the control unit, for converting the pulse width modulated signal (13) into an analog control voltage. Vehicle rear vision system according to one of Claims 1 to 17, characterized in that the control device comprises an analog-to-digital converter (15) for digitizing the control signal, the analog-to-digital converter is connected via a data bus to the digital-to-analog converter for conversion. of a digital signal to an analog control voltage. Vehicle rearview system according to claim 18, characterized in that the data bus protocol is based on a UART or CAN system. Vehicle rear vision system according to one of claims 1 to 19, characterized in that the heating resistor (3) is connected in series with a parallel connection comprising at least one electrochromic mirror (2) and a transistor. Vehicle rear vision system according to one of Claims 1 to 19, characterized in that the heating resistor (3), the electrochromic mirror (2) and the transistor are connected in series. Vehicle rear vision system according to one of claims 1 to 21, characterized in that the electrical connections within the control device and / or between the control device and the electrochromic mirrors are in the form of foil printed circuits.