Abstract: An electric power supply system for a vehicle has an electric power line wired in a loop configuration. From the electric power line power is supplied to a load, and to another system which supplies control system power supply. One shutdown circuit is provided in a module connected to the loop configured power supply line. When the electric power line and the load are short circuited, the shutdown can isolate and shut down only the failure point. Further, when the car is not in use, by stopping the power supply to the load, current consumption can be restrained. In response to detection of a ground short and a failure of a connection of a connector, an over-current prevention of an electric power line, a simple construction can be provided and a low current consumption can be realized.

Abstract: A monitor for a light circuit comprising a power source, a light being monitored, and a sense resistor. A first voltage amplifier circuit connected to the light circuit has a first output signal representing the voltage across the sense resistor. A second voltage amplifier circuit connected to the circuit has a second output signal representing the voltage across the sense resistor. A microprocessor is configured to receive the output signals from the first and second voltage measuring circuit and is programmed to calculate the current to the light based on the first and second digital output signals, compare the calculated current against a threshold current, and initiate a failure signal if the calculated current is less than the threshold current. A visual indicator activates if the microprocessor initiates a failure signal, whereby the activated indicator notifies that the light is not operating correctly.

Abstract: A vehicle light apparatus 1 includes a discharge lamp 7 as a dipped (low)-beam light source and a high-beam light source or a light source of an auxiliary light (incandescent lamp) 3 as a substitutional light source of the discharge lamp. If the apparatus detects an input voltage from a power supply becoming equal to or greater than a threshold value in a state that only the discharge lamp is lit, the incandescent lamp is automatically lit on. To use the high-beam light source in place of the discharge lamp, light extinction lighting is performed or the light application direction is directed downward from the horizontal direction.

Abstract: The invention relates to a modular safety switching device system for switching actuators fail-safely off. The system comprises at least one input module for fail-safely evaluating a safety transmitter and for generating an output signal. It further comprises at least one output module for fail-safely actuating the actuator in response to the output signal from the input module. At least the input module can be operated in different selectable operating modes. A control module is provided for individually setting the operating mode of the input module and, if applicable, of the output module. A display is provided for fail-safely displaying the operating modes set.

Abstract: A lamp's optical axis control system for a vehicle includes vehicle speed sensor, steering angle sensor, a circuit for calculating driver's viewpoint and a controller for controlling the optical axis according to the position of the driver's view point. The controller indicates the position of the driver's viewpoint a certain time in advance according to the vehicle speed signal and the steering angle signal. Therefore, the illumination range of the headlamps can timely provides a desirable driver's view point.

Abstract: The inventive vehicle switch assembly includes a switch for producing a signal to control a vehicle accessory, a light for illuminating the assembly, and a sensor for actuating the light in response to detecting an object in proximity to the switch. Preferably, the switch is illuminated only when a hand of a vehicle occupant is placed within a predetermined distance of the switch.

Abstract: An apparatus and method for delivering power from a D.C. voltage source to one or more D.C. loads rated at lower voltages. The invention provides for the repetitive application of the higher D.C. voltage to the loads for a predetermined time period sufficient for the load to operate yet not too long to ensure that the load will not be damaged. To implement the invention, a clock signal provides the time reference for separate slots allocated for the time periods associated with each of the loads. A user selectively enables or interrupts the repetitive connection to each of one of the loads. The rate of repetition of the connection of the high voltage source could vary from 60 to 200 Hertz, preferably without degrading the operation of typical loads.

Abstract: The present invention addresses the need to sustain brake lights illumination of a motor vehicle at substantially stationary state even after brake pedal is released in order to ensure traffic safety. This device employs a number of commonly available relays not only to sustain the power to the brake lights but also to monitor the state of the movement of the vehicle. The circuit is largely composed of three main sections: a power supply relay, a latching-unlatching relays and a sensor array. One common type of relays can be used to all three of these parts. Different from prior arts in this matter, no sensor on a power shaft is needed, although such device can be accommodated. Instead, simple tilting type mercury switches are used for sensing the acceleration of a vehicle. This device can be integrated with many other motion sensing devices. These sensor actions can also be blocked or supplemented by the engagement of the parking brake or the cruise control.

Abstract: The device has a sensor device (20) and an evaluation device (30). The sensor device (20) has a global sensor (22), by which the general light intensity in the surroundings of the vehicle is detected nondirectionally, and a directional sensor (24), by which the light intensity is detected directionally in the travel direction of the vehicle. By the evaluation device (30), the signals (S1, S2) of the sensors (22, 24) of the sensor device (20) are compared with threshold values (SE), and if at least one threshold value (SE) is undershot, the lighting devices (10, 12) are switched on. A temperature measuring instrument (32) for detecting the temperature of the sensor device (20) is also provided, which supplies the evaluation device with a signal (ST) about the temperature. In the evaluation device (30), temperature-dependent basic signals (S10, S20) that the sensors (22, 24) generate without light incidence are stored in memory.

Abstract: A method and system for providing daytime running lights in a vehicle is disclosed. The method and system include providing a power supply, at least one power management module and at least one headlamp. The at least one power management module is coupled with the power supply and includes at least one switch, at least one controller coupled with the at least one switch and at least one signal input. The at least one headlamp is coupled to the at least one power management module, with the at least one switch being coupled between the at least one headlamp and the power supply. The least one power management module automatically steps down the power to the at least one headlamp if it is determined that at least one condition is fulfilled.

Abstract: A system for enabling successful use of HID lamps in aircraft, including in particular high power lamps for use as landing lights and taxi lights, utilizes a sealed beam HID lamp which during normal operation has an external temperature considerably lower than the external temperature of a quartz halogen or incandescent sealed beam lamp of equivalent light output. The lower external temperature arises in part from the use of a gas fill in the sealed beam. A detector is provided to monitor the seal integrity of the sealed beam HID lamp and further to provide a response to seal failure resulting in disablement of the lamp. Exemplary ways for accomplishing seal failure detection include radioactive detection, pressure monitoring, and chemical sensing, or other ways wherein detection of a failed seal is followed by an electrical output used to terminate or preclude lamp operation.

Abstract: An electronic deceleration/accident warning system for a motor vehicle comprising a high energy flashing strobe light facing following traffic, and a control unit including a controller means for receiving input signals from a g-level sensor and a brake signal, and in response controlling the flash rate of the strobe light. Other optional inputs such as theft alarm and ABS are provided along with optional outputs such as safety belt tensioners and airbags.

Abstract: A vehicle switching system includes a controller, a headlamp switch, and a series resistor arrangement. The controller has an input connected to a voltage divider. The switch has a contact movable between positions with each position being associated with a respective headlamp function. The switch is connected to the input of the controller. A top end of each resistor has a connection point associated with a respective switch position. A bottom end of the resistor at the bottom of the series is connected to an electrical ground. Upon the switch contact contacting a connection point a circuit including the resistors between the ground and the connection point is formed such that a signal having a voltage is input to the controller. The voltage of the signal is dependent upon the resistance of the resistors forming the circuit. The controller enables the headlamp function corresponding to the voltage of the signal.

Abstract: A sensor device, by which the light intensity in the surroundings of the vehicle is detected and which is connected to an evaluation device, by which the signals (S) of the sensor device for the light intensity are compared with at least one threshold value, and from that it is ascertained whether a change in the switching state of the lighting devices is necessary. The evaluation device evaluates signals (S) of the sensor device for the presence of at least one periodically variable signal component (Sk), and in the presence of such a signal component (Sk), the lighting devices are either turned on at a certain level, or remain turned on at that level.

Abstract: A vehicle headlamp including a headlamp unit and an auxiliary lamp in which the brightness of an end portion of the low beam light distribution pattern formed by the beam irradiation from the headlamp unit is reinforced by the auxiliary light distribution pattern formed by the beam irradiation from the auxiliary lamp unit. The high luminous intensity area of the auxiliary light distribution pattern partly overlaps the high luminous intensity area of the low beam light distribution pattern, thus allowing the low beam light distribution pattern and the auxiliary light distribution pattern to be combined. Further, by way of controlling the beam irradiation intensity of the auxiliary lamp unit by a light control unit, the brightness of the low beam light distribution pattern is reinforced by the auxiliary light distribution pattern that has brightness in response to the vehicle running condition.

Abstract: The invention relates to a method for switching several electric circuits in a vehicle, wherein several positions of an actuating element are binarily coded, the binary codification is fed to a logic and the logic controls the switching of the electric circuits, and also a corresponding switch with an actuating element and a switching device for attaining several switching modes, depending upon the position of the actuating element, wherein the switching device is constructed of several switching elements with two switching modes each, so that there results a binary codification of the switching modes of all switching elements, depending upon the position of the actuating element in order to switch the electric circuits by means of a logic.

Abstract: A vehicular interior lighting system features a lamp assembly having two input terminals, each connected to a power source via two control switches. The lamp assembly further includes a lighting element connected at one end to an input terminal and at the other end to dual position manual switch that is connected in parallel to a diode. This configuration allows the lighting element to be illuminated from either the control switches or via the manual switch, depending on the polarity.

Abstract: Hitherto, when operating a wiper at intermittent intervals or dimming a headlight during one's vehicle being stopped, the wiper and headlight are not returned to a normal operation until the one's vehicle starts moving thereby making it hard to see around. The invention provides an improved control device of auxiliary apparatus for vehicle, in which when it is detected by a vehicle-ahead start detector 12 that a vehicle ahead starts moving and when a vehicle speed detector 11 detects that one's vehicle is stopped, the control device controls a peripheral recognition assist apparatus such as wiper 32 or headlight 42, and a peripheral recognition apparatus such as active sensor 52 of a near-infrared camera 54 so as to come under a state suitable for traveling thereby making it possible to recognition around one's vehicle and start the One's vehicle immediately.

Abstract: The architecture of an automotive wiring, power distribution and accessory control system is described. The system comprises semi-custom two-tier nodes which are distributed in locations around the vehicle to service load devices associated with or found in different regions of the automobile topology. A multiplexed control network interconnects the nodes along with a two-wire bus. Each node consists of a first common board carrying a microcontroller and a basic number of FET driver switches associated with a basic level of accessorization for that region of the vehicle. Each node further comprises a second larger pass through board which supports the first common board in spaced parallel relationship therewith and which carries terminal connectors. The larger pass through board has vacant locations for the addition of FET drivers needed for higher levels of accessorization. These locations are preconnected to the microcontroller but are unused in vehicles with lower levels of accessorization.

Abstract: A wiring harness for use with an emergency vehicle. The wiring harness can be an independent wiring harness added after the vehicle has been manufactured or it can be included in the original equipment manufacturer's wiring harness. The wiring harness permits the addition of emergency vehicle equipment, such as two-way radios, computers, radar guns, etc., without splicing into the original equipment manufacturer's wiring.

Abstract: A system and method for driving a load at a voltage higher than a normal driving voltage, being capable of reducing switching losses and heat generation amount. A load driving system 1 has a microcomputer 2, a DC/DC converter 3, and a semiconductor relay 5 provided to each lamp 4 as a load. The DC/DC converter 3 has a main switch 6, an auxiliary switch 7, and a resistor R1. A rectangular pulse signal at a desired duty ratio is given to the main switch 6 to turn the main switch 6 on and off, thereby to output a rectangular waveform voltage. A drive signal is given to the semiconductor relay 5 to supply the rectangular waveform voltage outputted from the DC/DC converter 3 to the lamp 4, illuminating the lamp 4.

Abstract: A combined four way and seven way connector assembly for communicating a towing vehicle's electrical system with either a four way or seven way input harness associated with a towed vehicle. The towing vehicle includes a wire harness supplying an output of the electrical system. The connector assembly provides a three dimensional housing including a top and a plurality of interconnected sides and which is secured to a suitable rear end location of the towing vehicle. A circuit board, or other suitable component, contains a plurality of electrical circuits and is secured within the housing. A first plurality of terminals defines a four way connector and a second plurality of terminals defines a seven way connector. Each of the first and second pluralities of terminals communicates with a selected number of said plurality of circuits and further define first and second input plugs accessible through the housing by the towed vehicle input harness.

Abstract: A power management system comprises a busboard for selectively managing the power from a forty-two volt source and a fourteen volt source in a vehicle dual voltage electrical system. The busboard has a lower plate with recesses for receiving variously configured busbars. The busbars have upright terminals for electrical connection with the voltage sources. The power from the voltage sources is directed along the busbars to other terminals extending at assorted locations from the busboard. An upper cover fits over the lower plate and covers the recesses. The upper cover has an area accommodating the forty-two volt source and housings for partially enclosing the other terminals. One of the housings forms a forty-two volt jump start post. Another of the housings forms a fourteen volt jump start post.

Abstract: The invention relates to a conversion system and method of converting a vehicle into a police car or similar emergency vehicle in a manner which is easily installed and removed and designed so that it causes no damage to the vehicle, thereby improving the resale value of the vehicle upon termination of the lease or retirement of the vehicle from service.

Abstract: A light-controlling device of this invention includes a controlling circuit having a function for turning an incandescent lamp and an LED off simultaneously, which have different minimum voltages each other at predetermined illumination. When illumination of the lamp and the LED decrease to the predetermined illumination by rotating an operating section of a variable resistor, the controlling circuit turns the lamp and the LED off based on a signal from a detecting switch linked with rotating operation of the operating section. As a result, an operator does not feel strange.

Abstract: A combined headlight and windshield wiper control switch for a vehicle that activates the parking lights, headlights and windshield wipers. The switch turns on the parking lights and headlights followed by the various windshield wiper settings. When turning the switch off, the switch uses different actuator movement or a locking mechanism to prevent the parking lights and headlights from being turned off when the windshield wipers are being turned off. The first embodiment uses a locking mechanism in the actuator to prevent the actuator from turning past the parking lights and headlights position. The actuator has a release button on the side that must be pressed to allow the actuator to turn to the off position. In the center of the actuator is another button that enables/disables the lighting circuit and the locking mechanism from the switch.

Abstract: In a power distributor for a vehicle, each of semiconductor switching elements 14 is disposed between an input terminal 10 and corresponding one of a plurality of output terminals 12. The semiconductor switching elements 14 are disposed in one direction and a control circuit board 18 is provided thereon. The input terminal 10, the output terminals 12 and board terminals 16 coupled to the control circuit board 18 are disposed in parallel to the arrangement direction of the semiconductor switching elements 14 and protruded from the casing 22 in the same direction to thereby directly form a connector.

Abstract: In a vehicle-mounted electrical component, potentially redundant resistances 4d, 4h, 4i and the corresponding voltage detecting circuit 5d, or the terminals 21, 22, 23, 24 and the switch for turning the switch interposed between the terminals 21 and 22, and the terminals 23 and 24 ON and OFF are exposed on the external surface of the main body so that setting according to the specifications can be performed outside the main body.

Abstract: A display control apparatus of a vehicle has, a vehicle key switch for switching on or off an application of electrical energy to the vehicle and for turning off headlights, a delay timer, for maintaining display operation of a display member for a predetermined time period after the vehicle key switch is turned off, a headlight switch for turning on or off the headlights when the key switch is turned on, a switch detect unit for detecting operation states of the key switch and the headlight switch and, a display drive control unit for controlling the display operation of the display member within a delay time set by using nighttime reduced brightness when the switch detect unit detects an off operation of the vehicle key switch in the case of the headlight switch being detected on so as to prevent unnecessary consumption of the battery capacity.

Abstract: The invention relates to a method for managing the supply to a discharge lamp of a motor vehicle headlight, wherein during the phase of starting up the discharge lamp, the strength of the current supplied to the lamp is controlled on the basis of a parameter representative of the environment of the vehicle so as to optimize the life of the discharge lamp. The invention also relates to a device for managing the supply to a discharge lamp.

Abstract: A discharge lamp device for a vehicle includes a lighting circuit for performing lighting controls of a discharge lamp for high beam and a discharge lamp for low beam, both lamps having the same rating. The lighting circuit controls the power supply such that the electrical power input when the discharge lamp for high beam is lighted is greater than the electrical power input when the discharge lamp for low beam is lighted.

Abstract: The present invention provides a control system for activating and controlling the reverse gear indicator lights of a vehicle. This Parallel Parking Aid (PPA) will comprise a button, switch or other means of manual or sensate activation, whereby the reverse gear indicator lights of a vehicle may be engaged without the vehicle being engaged in the reverse gear, and by which those reverse gear indicator lights may be caused to flash or blink.

Abstract: A circuit device for sustaining the illumination of a vehicle used high illumination discharged (HID) lamps is disclosed. The circuit device comprises: a high/low beam switching delay circuit, and an HID lamp set power supply circuit. The high/low beam lamp switching delay circuit includes a lamp switch; a polarity correction circuit; a time delay circuit; and an isolation circuit. The HID lamp set power supply circuit includes an isolation circuit; a large current conduction circuit; a battery; an HID lamp circuit. By above mentioned circuit device, when the lamp switch switches between high/low beam lamps of a vehicle, the low lamp beam is sustained to light up continuously, thereby, the lifetimes of the electronic ballasts and HIV lamp are prolonged.

Abstract: A plurality of lamps 21 to 28 inclusive are supplied with a voltage one after another in sequence. A time duration during which the voltage is supplied to each of the lamps 21 to 28 inclusive is controlled in PWM fashion to restrict an amount of voltage supplied thereto. A current detect circuit portion 36 solely detects all of the voltages supplied to the lamps 21 to 28 inclusive, respectively. Each of the voltages exceeds a threshold value, a dead band between two adjacent voltage supply durations. Thus, it is possible to restrict possible electromagnetic noises which are generated upon voltage supply to lamps 21 to 28 inclusive in a vehicular lamp control apparatus in which the lamps 21 to 28 inclusive are supplied with voltage from a high voltage battery 11.

Abstract: A device is provided for a motor vehicle of the type having a manual transmission including a clutch coupled to a clutch pedal. An actuator engaged to the clutch controls the actuation of one or more external indicator lights in response to the depression of the clutch pedal. Optionally, the system further includes a dashboard indicator light that is illuminated by the actuator upon depression of the clutch pedal.

Abstract: In a discharge lamp lighting circuit 1, a control circuit 7 detects a failure in a discharge lamp 8 or the lighting circuit to stop supplying the power to the discharge lamp 8 or stop the operation of the lighting circuit, or lights another light source as a substitute light source for the discharge lamp and notifies the occurrence of a failure when the discharge lamp 8 can no longer be lit. A delay time generator circuit 31 is provided for a failure detection/determination circuit 22 such that the foregoing functions are prohibited until a predefined time period is elapsed after the time switch means SW1, SW2 are substantially simultaneously switched on to cause the lighting circuit to start operating.

Abstract: The present invention relates to a lighting or indicating light unit for a vehicle. It also relates to a lighting or indicating system equipped with at least one such light unit. It extends directly to indicating devices, such as vehicle lights but also to other similar products such as reversing radars and other systems.

Abstract: A lamp's optical axis control system for a vehicle includes vehicle speed sensor, steering angle sensor, a circuit for calculating driver's viewpoint and a controller for controlling the optical axis according to the position of the driver's view point. The controller indicates the position of the driver's viewpoint a certain time in advance according to the vehicle speed signal and the steering angle signal. Therefore, the illumination range of the headlamps can timely provides a desirable driver's view point.

Abstract: An electrical tell tale system for trailers that consists of a unique tell tale monitor which is light weight which houses different colored light emitting diodes which define each individual trailer circuit. The tell tale monitor has an attached modular cable and modular plug which is connected by a modular socket to the main control unit. The main control unit has two protruding leads which are connected in series with the vehicles trailer wiring harness by connectors. The system works by scanning the trailer signals passing through the main control unit and specially set, wound resistive current sensing coils, which close a reed switch at the correct current which in turn sends a low voltage signal through the modular connection and through the modular cable to the tell tale monitor which will illuminate a certain light emitting diode to notify if the trailer circuit is operational.

Abstract: A method and a device are proposed for the automatic control of illumination devices (24), having a control element (22) which acts on illumination devices (24) and which is calibrated at time intervals (T), for which various calibration parameters are taken into account.

Abstract: It is an object to reliably decide the running area of a vehicle and to carry out suitable irradiation control for the area. This invention provides a lighting device 1 for a vehicle including irradiation control means 5 for deciding a running area based on position information obtained by vehicle current-position detecting means 2 and road information obtained by road information acquiring means 3 and for carrying out irradiation control of a lighting tool for a vehicle according to a result of the decision. For road information, a current running area (a high-speed running area, an urban area) is decided based on information in the current position of a vehicle and information about a road over which the vehicle has already run or the same information and information about the forward place of the vehicle.

Abstract: A headlamp's optical axis control system for a vehicle includes a infrared light camera for detecting an object on a road in front of the vehicle and a headlamp's optical axis actuator. The headlamp's optical axis is changed according to a vehicle speed and position of the object relative to the vehicle so that the illumination range of the headlamp can cover the object if the object is judged to be out of the illumination range.

Abstract: A battery is disposed at the portion beneath the rear seat of a vehicle. The positive electrode of the battery is connected through a power bus for power supply to a rear junction block (R-JB). A rear integration module (RIM) can be coupled to the R-JB through a plug-in operation. The positive electrode of the battery is also connected through a power bus to an under dash junction block (UD-JB). A body control module (BCM) can be coupled to the UD-JB through a plug-in operation. The power bus connection terminal of the UD-JB is connected to a fuse relay block (F-JB) through a power bus. A front integration module (FIM) can be coupled to the F-JB through a plug-in operation. The power bus connection terminal of the F-JB is connected to a starter motor through a power supply line and further connected to an alternator through a power supply line from the starter.

Abstract: A device for checking the evaluation circuit for automatic switching operations of the illumination devices in vehicles. A sensor device contains a global sensor for detecting the light conditions in the environment of the vehicle and a directional sensor for the directed detection of the light conditions in the direction of travel in front of the vehicle. The signals of the sensor device are supplied to the evaluation circuit, to determine whether a change in the switching state of the illumination devices is necessary. In order to check the evaluation circuit which is designed using analog technology, in the operating state, the voltage supply to the sensor unit is briefly interrupted at predetermined intervals, as a result of which the condition “night” is simulated. When the evaluation circuit is functioning correctly, this is detected by it as such.

Abstract: A keyless entry system for a motor vehicle is modified to be operable when the vehicle's engine is running and the vehicle's park brake is set. Keyless entry systems conventionally include an ignition switch position signal source and a door lock module having an enable input connected to the source of the ignition position signal. The disclosure teaches connecting the output of the ignition switch position sensor to the door lock modulo enable input through the part brake lamp. The enable input to the door lock module is then connected in common with the a park brake lamp switch. When the park brake lamp switch is closed by setting the park brake and activates the park brake lamp, the ignition position feed signal on the enable input is sunk by the switch and the potential level on the enable Is reduced, enabling the door lock module to operate as though the ignition switch had been moved to off.

Abstract: A method and device to automatically switch on and off the lights of a motor vehicle. The driving speed of the vehicle and the brightness readings from three light sensor cones of different sizes and directed in different directions are determined. The lights are switched either on or off based upon comparing the speed and three brightness readings to a set of possible conditions for each of the variables as the vehicle operates. The driving distance and time interval are also variables considered in determining whether to switch the lights on or off. Unnecessary on and off switching is avoided.

Abstract: An anti-glare system for motor vehicle headlights is effective to illuminate the headlights at reduced intensity when the vehicle is not in motion and the headlight switch is on thereby promoting better visibility for the driver of an oncoming vehicle. This system is believed particularly useful in service vehicles, such as pick-up and delivery trucks and school buses.

Abstract: The present invention pertains to an electrical circuit for operating warning lights that are commonly used on emergency and service vehicles. The electric circuit enables the use of pairs of 21 volt DC halogen lamps on a light bar installed on an emergency vehicle equipped with a 42 volt electrical system.

Abstract: A one-piece headlight adapter, and a two-piece headlight adapter system, is used to connect the existing vehicle headlight controls and power supply with a snowplow wiring harness. An adapter only connects the controls and power supply for one headlight to the wiring harness. Two adapters, one for each headlight, create an adapter system. The adapter system allows the vehicle operator to control the snowplow headlights from the inside of the vehicle. One version of an adapter is a three-component adapter that includes one connection to the vehicle headlight, one connection to the headlight controls, and one connection to the wiring harness. Another version of the adapter is a five-component adapter that includes high and low beam connections to the vehicle headlight, high and low beam connections to the headlight controls, and one connection to the wiring harness.

Abstract: An autoleveling device comprises a pair of left and right headlamps in which optical axes L are tilted in a vertical direction with respect to a body by driving operations of respective motors 10 (10L, 10R), single control means 16 for controlling the driving operations of the left and right motors 10 at the same time, a vehicle speed sensor 12, a height sensor 14 and a storage section 20 for storing pitch angle data detected by the height sensor 14, the control means 16 controlling the respective motors 10 such that the respective optical axes L have a predetermined inclination with respect to a road based on the pitch angle data thus detected, wherein the motors are driven only if a difference between the detected pitch angle and the pitch angle used for the last driving control of the motor is equal to or more than a predetermined reference value which is more than a pitch angle equivalent to a hysteresis width of each of the left and right motor driving circuits (|&thgr;2−&thgr;1|>&