JP7655067B2 - Vehicle lighting fixtures - Google Patents

Description

This disclosure relates to vehicle lighting.

Conventionally, a semiconductor light source lighting circuit that realizes a steeper temperature derating gradient is known. The conventional circuit includes a DC/DC converter that supplies current to the LED, a current detection resistor that generates a current detection voltage, a control unit that controls the DC/DC converter so as to reduce the difference between the current detection voltage and the comparison voltage, and a comparison voltage generation unit that generates a comparison voltage. The comparison voltage generation unit includes a temperature detection unit that generates a thermistor divided voltage according to the LED temperature, a voltage-current conversion unit that converts the thermistor divided voltage into a thermistor divided current with a coefficient determined by the resistance value of the sixth resistor, and a current application unit that passes an adjustment current of the same magnitude as the thermistor divided current through the first resistor (see, for example, Patent Document 1).

JP 2012-160277 A

Conventional semiconductor light source lighting circuits are configured with a function (hereinafter referred to as a "temperature derating function") that reduces the current applied to the semiconductor light source according to the temperature level when the temperature inside the lamp exceeds a certain level due to the surrounding environment when the headlights are turned on. However, while the current applied to the semiconductor light source is changing, the brightness of the semiconductor light source also changes in accordance with the change in the applied current. Therefore, if the flashing operation is performed multiple times while the current applied to the semiconductor light source is changing, the brightness of the semiconductor light source also changes each time, and when a signal is conveyed to the other party by flashing the headlights to blink, the change in brightness gives the other party a sense of discomfort.

This disclosure was made with a focus on the above problem, and aims to provide a vehicle lamp that can prevent the discomfort felt by other people due to changes in brightness when the flashing operation is performed multiple times while the current applied to the light source is changing.

In order to achieve the above object, the vehicle lamp of the present disclosure includes a headlight light source, a light source lighting circuit connected to the light source, and a lamp controller connected to the light source lighting circuit. In this vehicle lamp, the light source lighting circuit has a circuit configuration that has a function of reducing the current applied to the light source according to the temperature level when the temperature inside the lamp reaches or exceeds a predetermined temperature due to the surrounding environment when the headlight is turned on. The lamp controller has a light source current control unit that outputs a fixation command to the light source lighting circuit when a passing operation is performed while the current applied to the light source is changing, to fix the current applied to the light source at the time of the passing operation until a set time has elapsed since the passing operation. When the set time during which the fixation command for the applied current has been output has elapsed, the light source current control unit releases the fixation of the applied current and outputs a command to restore the applied current-temperature relationship characteristic from the current-temperature operating point at the time the set time has elapsed to the applied current-temperature relationship characteristic by the upper limit gradient angle of the light source lighting circuit.

Therefore, when multiple flashing operations are performed while the applied current to the light source is changing, it is possible to prevent the other party from feeling uncomfortable due to changes in brightness. Furthermore, after the application current is fixed, the applied current-temperature relationship characteristics can be restored with good response to temperature increases and decreases.

1 is an overall configuration diagram showing a semiconductor light source control unit of a headlamp which is a vehicle lamp according to a first embodiment of the present invention; 5 is a flowchart showing the flow of an applied current control process in a light source current control unit of the lamp controller of the first embodiment. FIG. 11 is an applied current-temperature relationship characteristic diagram showing the relationship between the applied current and temperature when two passing operations are performed in the middle of a decrease in the applied current due to a rise in temperature inside the lamp in a semiconductor light source lighting circuit of a comparative example. 1 is an applied current-temperature relationship characteristic diagram showing the relationship between the applied current and temperature when two passing operations are performed in the middle of a period in which the applied current is decreasing due to a rise in temperature inside the lamp in the semiconductor light source lighting circuit of Example 1. FIG. 10 is a flowchart showing the flow of an applied current control process in a light source current control unit of a lamp controller according to a second embodiment.

Below, a description will be given of a form for implementing a vehicle lamp according to the present disclosure based on Example 1 and Example 2 shown in the drawings.

The vehicle lamp in Example 1 is applied to a semiconductor light source control unit of a headlamp having a high beam LED light source and a low beam LED light source, which are part of a front combination lamp installed on the left and right sides of the front of an automobile.

First, the configuration of the headlamp semiconductor light source control unit A will be described with reference to Figure 1.

As shown in FIG. 1, the semiconductor light source control unit A includes a headlamp 1, a high beam LED light source 2, a low beam LED light source 3, an on-board power source 4, a light switch 5, a semiconductor light source lighting circuit 6, a lamp controller 7, and a passing operation sensor 8. Here, LED is an abbreviation for "Light Emitting Diode." The high beam LED light source 2 and the low beam LED light source 3 are examples of light sources, and are hereinafter referred to as "LED light sources 2, 3."

The headlamp 1 is constructed by combining LED light sources 2, 3 with optical components such as a lens body and a reflector (not shown) and arranging them inside the lamp housing 10. Inside the lamp housing 10, in addition to the LED light sources 2, 3, a semiconductor light source lighting circuit 6 is arranged in a position close to the LED light sources 2, 3. Note that the semiconductor light source lighting circuit 6 may be arranged outside the lamp housing 10 instead of inside it.

The semiconductor light source lighting circuit 6 is a drive circuit that controls the on/off/applied current of the LED light sources 2 and 3, which are semiconductor light sources, and is called an LED driver. The first output terminal 6a of the semiconductor light source lighting circuit 6 is connected to the high beam LED light source 2 by a first conductive harness 21. The second output terminal 6b of the semiconductor light source lighting circuit 6 is connected to the low beam LED light source 3 by a second conductive harness 31. The power supply terminal 6c of the semiconductor light source lighting circuit 6 is connected to the on-board power supply 4 via the light switch 5 by a power supply harness 41.

The circuit board of the semiconductor light source lighting circuit 6 is provided with a temperature sensor 61 along with a DC/DC converter, etc. The semiconductor light source lighting circuit 6 has a circuit configuration with a temperature derating function that reduces the applied current I to the LED light sources 2, 3 according to the level of temperature T when the temperature T inside the lamp exceeds a predetermined temperature due to the surrounding environment when the headlamp 1 is turned on (see FIG. 3). Here, the "temperature derating function" refers to a function that operates the semiconductor light source lighting circuit 6 and the LED light sources 2, 3 with an applied current I equal to or less than a rated current value that is predetermined according to the level of temperature T inside the lamp, for the purpose of protecting the semiconductor light source lighting circuit 6 and the LED light sources 2, 3 from thermal deterioration.

For example, when the temperature T rises, as shown by arrow B in FIG. 3, the applied current I is reduced in response to the rise in temperature T, thereby realizing the temperature derating function. While the temperature is below the first set temperature T1, the applied current I to the LED light sources 2, 3 is fixed at the first rated current I1 (basic rated current). When the temperature T reaches or exceeds the first set temperature T1, the first rated current I1 applied to the LED light sources 2, 3 is reduced in response to the rise in temperature. When the temperature T reaches or exceeds the second set temperature T2, the applied current I to the LED light sources 2, 3 is fixed at the second rated current I2 (high temperature range rated current).

Conversely, when the temperature T inside the lamp drops from the fixed state of the second rated current I2 (high temperature range rated current), the applied current I is increased in response to the drop in temperature T, as shown by arrow C in FIG. 3, thereby realizing a return to the first rated current I1 (basic rated current). When the temperature T drops below the second set temperature T2, the second rated current I2 applied to the LED light sources 2, 3 is increased in response to the drop in temperature. When the temperature T reaches the first set temperature T1, the applied current I to the LED light sources 2, 3 is fixed to the first rated current I1. Note that the relationship is first set temperature T1 < second set temperature T2, and the relationship is first rated current I1 > second rated current I2.

An NTC thermistor or the like is used as the temperature sensor 61, and detects the temperature inside the lamp around the LED light sources 2, 3. The temperature sensor 61 is particularly disposed in the interior space of the lamp housing 10 in which the LED light sources 2, 3 are mounted, at a position near the LED light sources 2, 3 so that the resistance value changes in good response to an increase or decrease in the temperature around the LED light sources 2, 3.

When the driver's flashing operation is detected by the flashing operation sensor 8, the lamp controller 7 performs a flashing control for switching the lighting state of the headlamp 1 with respect to the semiconductor light source lighting circuit 6, and also controls the current applied to the LED light sources 2 and 3. The first output terminal 7a of the lamp controller 7 is connected to the semiconductor light source lighting circuit 6 by a first output signal line 74. The second output terminal 7b of the lamp controller 7 is connected to the semiconductor light source lighting circuit 6 by a second output signal line 75. The first input terminal 7c of the lamp controller 7 is connected to the flashing operation sensor 8 by a first input signal line 76. The second input terminal 7d of the lamp controller 7 is connected to the temperature sensor 61 by a second input signal line 77. The lamp controller 7 has a flashing control circuit 71, a light source current control unit 72, and a timer 73.

Here, "passing" refers to a method of communicating with drivers of oncoming vehicles by temporarily turning on the headlights 1 in high beam when the vehicle is being driven, or by temporarily switching the headlights 1 in low beam to high beam when the headlights 1 are in low beam.

The passing operation sensor 8 is a sensor that detects the passing operation by the driver who pulls the operating lever 9 of the light switch 5 toward himself (arrow D in Figure 1) and then releases the operating lever 9 to return it to its original lever position. Here, the operating lever 9 is installed at the top of the steering column close to the steering wheel, protruding in the vehicle width direction, etc.

The light switch 5 is built into the operating lever 9, and the switch mode position is changed by rotating the operating lever 9 stepwise in the direction of the arrow E in FIG. 1. Examples of switch mode positions include the off position, auto light position, width light position, and headlight position. In the off position, all exterior lamps are turned off. In the auto light position, the headlight 1, width light, tail light, and other lamps are automatically turned on by sensor detection. In the tail light position, the width light and tail light are turned on. In the headlight position, the headlight 1, width light, and tail light are turned on. The light switch 5 is turned on when it is switched from the off position to the auto light position or the headlight position.

When the driver's flashing operation is input by the flashing operation sensor 8, the passing control circuit 71 performs passing control to switch the lighting state of the headlights 1 to the semiconductor light source lighting circuit 6. When it detects that the operation lever 9 has been pulled toward the driver, it outputs a high beam lighting command to the semiconductor light source lighting circuit 6 while the operation lever 9 is being pulled toward the driver. After that, when it detects that the operation lever 9 is released, it outputs a command to the semiconductor light source lighting circuit 6 to turn off the high beam headlights 1 or a command to switch to low beam lighting. Note that when the light switch 5 is turned off to turn off the headlights 1, the semiconductor light source lighting circuit 6 is disconnected from the on-board power source 4, but when the flashing operation is performed, the light switch 5 automatically switches from off to on.

The light source current control unit 72 receives the operation sensor signal from the passing operation sensor 8 and the temperature sensor signal from the temperature sensor 61, and controls the applied current I to the LED light sources 2 and 3. If a passing operation is performed while the applied current to the LED light sources 2 and 3 is changing, a fixation command is output to the semiconductor light source lighting circuit 6 to fix the applied current to the LED light sources 2 and 3 at the time of the passing operation until the first set time ST1 has elapsed since the passing operation. The timer 73 counts the time from the passing operation until the first set time ST1 has elapsed. Here, the case where the light source current control unit 72 performs the same current control for the two LED light sources 2 and 3 has been described. However, if the current control is performed separately for the two LED light sources 2 and 3, the applied current may be controlled only for the high beam LED light source 2 that is turned on during the passing operation.

Here, the light source current control unit 72 determines that the applied current I to the LED light sources 2 and 3 is changing when the temperature T acquired by the temperature sensor signal from the temperature sensor 61 is in the temperature range from the first set temperature T1 to the second set temperature T2.

The light source current control unit 72 determines the first set time ST1 after the passing operation is performed based on the time required when the passing operation is performed multiple times. In other words, the time required when the passing operation is performed multiple times is verified by an experiment or the like, and the first set time ST1 is determined by adding the required time based on the verification result to the time for variation due to individual differences.

When the first set time ST1 during which the light source current control unit 72 outputs a command to fix the applied current I has elapsed, it releases the fixation of the applied current I. Then, it outputs a command to restore the applied current-temperature relationship characteristics from the current-temperature operating point at the time when the first set time ST1 has elapsed, using the upper limit range gradient angle θmax in the semiconductor light source lighting circuit 6. Here, the "upper limit range gradient angle θmax" refers to the gradient angle of the upper limit range that can be realized in the semiconductor light source lighting circuit 6, among the gradient angles at which the applied current I decreases with respect to an increase in temperature T, or the gradient angles at which the applied current I increases with respect to a decrease in temperature T.

Next, the action of the first embodiment will be explained by dividing it into "action of the applied current control process in the light source current control unit," "comparison action when a passing operation is performed while the applied current is decreasing," and "characteristic action of the applied current control."

The flow of the applied current control process in the light source current control unit 72 of the lighting controller 7 will be described with reference to the flowchart in Figure 2. Note that the flowchart in Figure 2 starts when the light switch 5 is turned off and then on, and is repeated until the light switch 5 is turned off.

When the applied current to the LED light sources 2 and 3 has not changed, the flow from S11 to return is repeated, and the applied current is not fixed by the light source current control unit 72. In other words, when the temperature T is less than the first set temperature T1 or when the temperature T is greater than the second set temperature T2, it is determined that the applied current to the LED light sources 2 and 3 has not changed.

When the applied current to the LED light sources 2 and 3 is changing but there is no flashing operation, the flow of S11 → S12 → Return is repeated, and the applied current is not fixed by the light source current control unit 72. In other words, when the temperature T is within the range of the first set temperature T1 or higher and the second set temperature T2 or lower, it is determined that the applied current to the LED light sources 2 and 3 is changing.

When the applied current to the LED light sources 2, 3 is changing and a passing operation is performed, the process proceeds to S11 → S12 → S13 → S14 → S15. In step S13, if a passing operation is performed, a timer value corresponding to a first set time ST1 is set. In step S14, if a passing operation is performed, the applied current to the LED light sources 2, 3 is fixed to the applied current when the passing operation was performed. In S15, it is determined whether the duration since the passing operation has elapsed the first set time ST1.

In step S15, while it is determined that the duration since the passing operation has not elapsed the first set time ST1, the process repeats from S15 to S16, and in step S16, the previous timer value is decreased according to the processing cycle.

On the other hand, if it is determined in step S15 that the duration since the passing operation has elapsed the first set time ST1, the process proceeds from step S15 to step S17. In step S17, the application current I is released from the fixed state, and a command is output to the semiconductor light source lighting circuit 6 to restore the applied current/temperature relationship characteristic (FIG. 3) from the operating point (Ic, Te) at the time when the first set time ST1 has elapsed to the applied current before the application current was fixed, and the process proceeds to RETURN.

Referring to Figures 3 and 4, we will explain the comparative effect when a passing operation is performed while the applied current is decreasing.

In the comparative example, in a semiconductor light source lighting circuit having a temperature derating function, the higher the temperature T inside the lamp is, the lower the applied current I is, even if a passing operation is performed. In the comparative example, if the passing operation is performed multiple times while the applied current I to the semiconductor light source is changing, the brightness of the semiconductor light source also changes with the change in applied current I.

Therefore, as shown in Figure 3, when the first flashing operation is performed at temperature Ta (> T1) when the applied current I is decreasing due to a rise in temperature T inside the lamp in the semiconductor light source lighting circuit, the applied current I becomes Ia. After that, when the second flashing operation is performed at temperature Tb (> Ta) when the applied current I is decreasing, the applied current I becomes Ib (< Ia). Note that if the temperature T rises while the high beams are on, the applied current I will decrease slightly from Ia and Ib as the temperature rises.

In this way, in the temperature range (T1 ≤ temperature T ≤ T2) where the applied current I changes, for example, if the flashing operation is performed twice, the brightness of the semiconductor light source changes so that the second time is dimmer than the first time. As a result, in the comparative example, when a signal is conveyed to the other party by flashing the headlights multiple times, the change in brightness gives the other party a sense of discomfort.

In contrast, in Example 1, if a flashing operation is performed while the applied current to the LED light sources 2 and 3 is changing, the applied current Ic to the LED light sources 2 and 3 at the time of the first flashing operation is fixed until the first set time ST1 has elapsed since the first flashing operation. In other words, in the case of Example 1, even if multiple flashing operations are performed, the brightness of the LED light sources 2 and 3 does not change due to the fixation of the applied current Ic, so long as the flashing operation is performed before the first set time ST1 has elapsed.

Therefore, as shown in FIG. 4, when the first flashing operation is performed at temperature Tc in the semiconductor light source lighting circuit 6 where the applied current I is decreasing due to an increase in temperature T inside the lamp, the applied current I is fixed to the applied current Ic at the start of detection of the flashing operation. Thereafter, even if a second flashing operation is performed at temperature Td (>Tc) where the applied current Ic is being maintained, the applied current I remains fixed to Ic. In addition, even if the temperature T rises while the high beams are still on, the applied current I remains fixed to Ic.

In this way, in the temperature range (T1 ≦ temperature T ≦ T2) where the applied current I changes, for example, when the flashing operation is performed twice, the brightness of the LED light sources 2, 3 is maintained at the same brightness for the first and second times. As a result, when a signal is conveyed to the other party by flashing the headlight 1 multiple times, it is possible to prevent the other party from feeling uncomfortable due to the change in brightness. Here, the discomfort caused by the change in brightness includes the discomfort caused by the brightness of the headlight 1 becoming darker due to an increase in temperature T, and the discomfort caused by the brightness of the headlight 1 becoming brighter due to a decrease in temperature T.

Next, we will explain the characteristic effects of applied current control.

In the semiconductor light source lighting circuit 6 of the first embodiment, a temperature sensor 61 that detects the temperature T inside the lamp is provided in the circuit, and the circuit is configured to have a relationship characteristic in which the applied current I changes according to the temperature T when the temperature T is in the temperature range from the first set temperature T1 to the second set temperature T2. In the light source current control unit 72, a sensor signal from the temperature sensor 61 is input, and when the temperature T acquired by the sensor signal is in the temperature range from the first set temperature T1 to the second set temperature T2, it is determined that the applied current I to the LED light sources 2, 3 is changing.

That is, the determination that the applied current I to the LED light sources 2, 3 is changing can be made by directly detecting the change in the applied current I to the LED light sources 2, 3. However, in this case, since a monitoring time required to confirm that the applied current I is changing is set, the determination that the applied current I to the LED light sources 2, 3 is changing is made after the monitoring time has elapsed, and the timing of the determination is delayed. In response to this, attention has been paid to the fact that the temperature sensor 61 is provided in the circuit of the semiconductor light source lighting circuit 6, and that the semiconductor light source lighting circuit 6 has a circuit configuration having a relationship characteristic in which the applied current I changes depending on the temperature T when in a predetermined temperature range. In other words, when the temperature T acquired by the temperature sensor 61 is in the temperature range from the first set temperature T1 to the second set temperature T2, it is determined that the applied current I to the LED light sources 2, 3 is changing. Therefore, by determining that the applied current I to the LED light sources 2, 3 is changing based on the temperature T in the lamp acquired from the temperature sensor 61, the delay in the timing of determining that the applied current I is changing is prevented.

In the light source current control unit 72 of the first embodiment, the passing operation sensor 8 is used, and when the lever operation of pulling the operating lever 9 of the light switch 5 toward the driver is detected, it is determined that a passing operation has been performed.

In other words, when the driver operates the flashing lights, it is necessary to know the flashing operation, including the start of the flashing operation, with good response. In response to this, we focused on the fact that the flashing operation is performed by pulling the operating lever 9 of the light switch 5 toward ourselves. Therefore, by using the flashing operation sensor 8 that detects the lever operation, it is possible to responsively detect the intervention of the flashing operation, including the start of the flashing operation.

In the light source current control unit 72 of the first embodiment, when the first set time ST1 during which a command to fix the applied current I has elapsed, the fixation of the applied current I is released. Then, from the current-temperature operating point (Ic, Te) at the time when the first set time ST1 has elapsed, a command is output to return to the applied current-temperature relationship characteristic (Figure 4) by the upper limit range gradient angle θmax in the semiconductor light source lighting circuit 6.

In other words, the fixed control of the applied current I is a control in which the current-temperature operating point deviates from the current-temperature operating point on the applied current-temperature relationship characteristic that exerts the temperature derating function. Therefore, when the fixed control of the applied current I is released, it is necessary to return the current-temperature operating point to the original applied current-temperature relationship characteristic. At this time, as shown by the dashed line in Figure 4, a comparative example is one in which the current-temperature operating point (Ic, Te) at the time when the first set time ST1 has elapsed is returned to the applied current-temperature relationship characteristic by the characteristic gradient angle θn in the semiconductor light source lighting circuit 6. In this comparative example, when the applied current-temperature relationship characteristic is returned to, the current-temperature operating point becomes (I2, T3).

In contrast, in the case of Example 1, as shown by the solid line in FIG. 4, the semiconductor light source lighting circuit 6 returns to the applied current-temperature relationship characteristic from the current-temperature operating point (Ic, Te) at the time when the first set time ST1 has elapsed, due to the upper limit range gradient angle θmax. Therefore, when the applied current-temperature relationship characteristic is returned to, the current-temperature operating point becomes (I2, T2) (T2<T3). Therefore, after the fixed control of the applied current I is completed, the applied current-temperature relationship characteristic can be returned to with good response to the rise or fall of the temperature T. In particular, by returning to the applied current-temperature relationship characteristic with good response when the temperature T is rising, the function of protecting the semiconductor light source lighting circuit 6 and the LED light sources 2 and 3 from thermal deterioration can be maintained.

In the light source current control unit 72 of the first embodiment, the set time after the passing operation is set to a first set time ST1 that is determined based on the time required when the passing operation is performed multiple times.

In other words, in accordance with the fact that the problem occurs when multiple passing operations are performed, the set time from the passing operation is determined based on the time required when multiple passing operations are performed. Therefore, by using a simple control process in which the duration for which the applied current I is fixed is set to a single, determined first set time ST1, it is possible to prevent the other party from feeling uncomfortable due to the change in brightness when a signal is conveyed to the other party by multiple passing operations.

As described above, the vehicle lamp of Example 1 provides the following advantages:

(1) The headlamp 1 includes a light source (LED light source 2, 3), a light source lighting circuit (semiconductor light source lighting circuit 6) connected to the light source (LED light source 2, 3), and a lamp controller 7 connected to the light source lighting circuit (semiconductor light source lighting circuit 6). In this vehicle lamp, the light source lighting circuit (semiconductor light source lighting circuit 6) has a circuit configuration that has a function of reducing the applied current I to the light source (LED light source 2, 3) according to the level of temperature T when the temperature T in the lamp becomes equal to or higher than a predetermined temperature (first set temperature T1) due to the surrounding environment when the headlamp 1 is turned on. The lamp controller 7 has a light source current control unit 72 that outputs a fixation command to the light source lighting circuit (semiconductor light source lighting circuit 6) when a passing operation is performed while the applied current I to the light source (LED light source 2, 3) is changing, to fix the applied current I to the light source (LED light source 2, 3) at the time of the passing operation until a set time (first set time ST1) has elapsed since the passing operation. This prevents the other party from feeling uncomfortable due to changes in brightness when multiple flashing operations are performed while the applied current I to the light sources (LED light sources 2 and 3) is changing.

(2) The light source lighting circuit (semiconductor light source lighting circuit 6) is provided with a temperature sensor 61 for detecting the temperature T inside the lamp, and has a circuit configuration having a relationship characteristic in which the applied current I changes according to the temperature T when the temperature T is in the temperature range from the first set temperature T1 to the second set temperature T2. The light source current control unit 72 inputs a sensor signal from the temperature sensor 61, and when the temperature T acquired by the sensor signal is in the temperature range from the first set temperature T1 to the second set temperature T2, it determines that the applied current I to the light source (LED light sources 2, 3) is changing. Therefore, by determining that the applied current I to the light source (LED light sources 2, 3) is changing based on the temperature T inside the lamp acquired from the temperature sensor 61, it is possible to prevent a delay in determining that the applied current I is changing.

(3) Using the passing operation sensor 8, the light source current control unit 72 determines that a passing operation has occurred when it detects a lever operation of pulling the operating lever 9 of the light switch 5 toward itself. Therefore, by using the passing operation sensor 8 that detects lever operation, it is possible to responsively detect the intervention of a passing operation, including the start of a passing operation.

(4) When the set time (first set time ST1) during which the light source current control unit 72 outputs a command to fix the applied current I has elapsed, the light source current control unit 72 releases the fixation of the applied current I. Then, from the current-temperature operating point (Ic, Te) at the time when the set time (first set time ST1) has elapsed, a command is output to restore the applied current-temperature relationship characteristics using the upper limit gradient angle θmax in the light source lighting circuit (semiconductor light source lighting circuit 6). Therefore, after the fixed control of the applied current I is completed, the applied current-temperature relationship characteristics can be restored with good response to an increase or decrease in temperature T.

(5) The light source current control unit 72 sets the set time after the flashing operation to a first set time ST1 that is determined based on the time required when the flashing operation is performed multiple times. Therefore, by using a simple control process that sets the duration for which the applied current I is fixed to the single determined first set time ST1, it is possible to prevent the other party from feeling uncomfortable due to changes in brightness when a signal is conveyed to the other party by multiple flashing operations.

Example 2 is an example in which the method of determining the set time after a passing operation is performed is different from Example 1.

The overall configuration of the second embodiment is the same as that of the semiconductor light source control unit A of the headlamp 1 of the first embodiment shown in FIG. 1. Below, the configuration of the light source current control unit 72 that differs from that of the first embodiment will be described.

The light source current control unit 72 sets the set time from the start of the passing operation as the second set time ST2, which is determined based on the required time from the first passing operation to the second passing operation when consecutive passing operations are performed. When the applied current I to the LED light sources 2, 3 is fixed due to a passing operation, if the next passing operation occurs before the second set time ST2 has elapsed, the remaining time is reset to the second set time ST2 from the next passing operation. In other words, when two consecutive passing operations are performed, the required time for the first passing operation is verified by experiment, etc., and the time interval from the end of one passing operation to the start of the next passing operation is verified by experiment, etc. Then, the required time based on the verification result is added to the time interval and the variation time to determine the second set time ST2 (ST1>ST2). Note that other configurations are the same as those in the first embodiment, so explanations are omitted.

Next, the flow of the applied current control process in the light source current control unit 72 of the lamp controller 7 in the second embodiment will be described with reference to the flowchart in FIG. 5. The flowchart in FIG. 5 starts when the light switch 5 is turned off and then on, and is repeated until the light switch 5 is turned off.

When the applied current to the LED light sources 2 and 3 has not changed, the flow of proceeding from S21 to return is repeated. When the applied current to the LED light sources 2 and 3 has changed but there is no passing operation, the flow of proceeding from S21 to S22 to return is repeated. In either case, the applied current is not fixed by the light source current control unit 72, as in the first embodiment.

When the current applied to the LED light sources 2, 3 has changed and there has been a passing operation, the process proceeds to S21 → S22 → S23 → S24 → S25. In step S23, if there has been a passing operation, a timer value corresponding to the second set time ST2 is set. In step S24, if there has been a passing operation, the current applied to the LED light sources 2, 3 is fixed to the current applied at the start of the passing operation detection. In S25, it is determined whether the duration since the passing operation has occurred has elapsed the second set time ST2.

In step S25, if it is determined that the duration since the passing operation has not elapsed the second set time ST2, and there is no next passing operation, the flow from S25 to S26 to S28 is repeated. In step S28, the previous timer value is decreased according to the processing cycle.

After that, in step S25, if it is determined that the duration from the start of the passing operation detection has not exceeded the second set time ST2, and the next passing operation is performed, the flow from S25 to S26 to S27 is repeated. In step S27, the timer value that has been decreased is reset to the timer value corresponding to the second set time ST2.

On the other hand, if it is determined in step S25 that the duration from the start of the passing operation detection has exceeded the second set time ST2, the process proceeds from step S25 to step S29. In step S29, the application current I is released from the fixed state, and a command is output to the semiconductor light source lighting circuit 6 to restore the applied current/temperature relationship characteristic (FIG. 3) from the operating point (Ic, Te) at the time when the second set time ST2 has passed to the applied current before the application current was fixed, and the process proceeds to RETURN.

In the light source current control unit 72 of the second embodiment, the set time from the passing operation is set to a second set time ST2 that is determined based on the time required from the first passing operation to the second passing operation when passing operations are performed consecutively. When the applied current I to the LED light sources 2, 3 is fixed due to a passing operation, if the next passing operation occurs before the second set time ST2 has elapsed, the remaining time is reset to the second set time ST2 from the next passing operation.

That is, the second set time ST2 (< ST1) is determined based on the time required from the first passing operation to the second passing operation when passing operations are performed consecutively. Therefore, if only one passing operation is performed in step S22, the fix of the applied current I is released when the second set time ST2 has elapsed since the passing operation. Therefore, if only one passing operation is performed, the fix of the applied current I is released when the second set time ST2 (< first set time ST1) has elapsed, so that it is possible to prevent the fixation of the applied current I from continuing for longer than necessary.

If the next passing operation occurs before the second set time ST2 has elapsed, the remaining time at that time is reset to the second set time ST2 from the start of detection of the next passing operation. Therefore, if the passing operation is performed multiple times in succession, and the next passing operation is performed before the second set time ST2 is reached, the applied current I will remain fixed regardless of the number of passing operations performed due to the resetting of the set time. Therefore, if the passing operation is performed multiple times in succession, it is possible to prevent the applied current I from being released from the fix in the middle of the passing operation, regardless of the number of times.

As described above, the vehicle lamp of Example 2 provides the following advantages in addition to the advantages (1) to (4) of Example 1.

(6) The light source current control unit 72 sets the set time from the passing operation to a second set time ST2 that is determined based on the time required from the first passing operation to the second passing operation when passing operations are performed consecutively. When the applied current I to the light source (LED light source 2, 3) is fixed upon detection of a passing operation, if the next passing operation occurs before the second set time ST2 has elapsed, the remaining time is reset to the second set time ST2 from the next passing operation. Therefore, when a passing operation is performed only once, it is possible to prevent the applied current I from being fixed for longer than necessary. In addition, when passing operations are performed multiple times in succession, it is possible to prevent the applied current I from being released from the fix in the middle of a passing operation regardless of the number of times.

The vehicle lamp of the present disclosure has been described above based on Examples 1 and 2, but the specific configuration is not limited to these Examples, and design changes and additions are permitted as long as they do not deviate from the gist of the invention according to each claim in the scope of the claims.

In the first and second embodiments, an example is shown in which a semiconductor light source consisting of a high beam LED light source 2 and a low beam LED light source 3 is used as the light source. However, the light source is not limited to an LED light source, and other semiconductor light sources that handle high currents, such as a semiconductor laser light source, may be used. Furthermore, the light source is not limited to a semiconductor light source, and may be a halogen light source or a discharge light source equipped with a light source lighting circuit having a temperature derating function.

In the first and second embodiments, an example was shown in which the semiconductor light source lighting circuit 6 has a circuit configuration having a relationship characteristic in which the applied current I changes depending on the temperature T when the temperature T from the temperature sensor 61 provided in the circuit is in the temperature range from the first set temperature T1 to the second set temperature T2. However, the semiconductor light source lighting circuit may also have a circuit configuration having a relationship characteristic in which the applied current changes depending on the temperature when the temperature from the temperature sensor provided in the circuit is equal to or higher than a predetermined temperature. In this case, the light source current control unit determines that the applied current to the semiconductor light source is changing when the temperature from the temperature sensor is equal to or higher than the predetermined temperature.

In the first and second embodiments, a preferred example is shown in which the light source current control unit 72 restores the applied current-temperature relationship characteristics from the current-temperature operating point at the time when the set time has elapsed by using the upper limit gradient angle θmax in the semiconductor light source lighting circuit 6 when the applied current I is released. However, the light source current control unit may also be an example in which the applied current-temperature relationship characteristics are restored from the current-temperature operating point at the time when the set time has elapsed by using an appropriately set gradient angle when the applied current is released.

A Semiconductor light source control unit 1 Headlight 2 High beam LED light source (light source)
3. Low beam LED light source (light source)
4. On-board power supply 5. Light switch 6. Semiconductor light source lighting circuit (light source lighting circuit)
61 Temperature sensor 7 Lamp controller 71 Passing control unit 72 Light source current control unit 8 Passing operation sensor 9 Operation lever T Temperature I Applied current T1 First set temperature T2 Second set temperature ST1 First set time ST2 Second set time

Claims (6)

A vehicle lamp including a headlight light source, a light source lighting circuit connected to the light source, and a lamp controller connected to the light source lighting circuit,
the light source lighting circuit is configured to have a function of reducing a current applied to the light source in accordance with the level of a temperature inside the lamp when the temperature inside the lamp exceeds a predetermined temperature due to a surrounding environment when the headlight is turned on,
the lamp controller has a light source current control unit that outputs a fixation command to the light source lighting circuit when a passing operation is performed while a current applied to the light source is changing, to fix the current applied to the light source at the time of the passing operation until a set time has elapsed since the passing operation ,
the light source current control unit releases the fixation of the applied current when the set time during which the fixation command for the applied current has elapsed;
a command is output to restore an applied current-temperature relationship characteristic from a current-temperature operating point at a point when the set time has elapsed to an upper limit range gradient angle by the light source lighting circuit . A vehicle lamp including a headlight light source, a light source lighting circuit connected to the light source, and a lamp controller connected to the light source lighting circuit,
the light source lighting circuit is configured to have a function of reducing a current applied to the light source in accordance with the level of a temperature inside the lamp when the temperature inside the lamp exceeds a predetermined temperature due to a surrounding environment when the headlight is turned on,
the lamp controller has a light source current control unit that outputs a fixation command to the light source lighting circuit when a passing operation is performed while a current applied to the light source is changing, to fix the current applied to the light source at the time of the passing operation until a set time has elapsed since the passing operation ,
The light source current control unit sets the set time from when the flashing operation is performed to a first set time determined based on a required time when the flashing operation is performed multiple times . The vehicular lamp according to claim 1 or 2 ,
the light source lighting circuit is provided with a temperature sensor in its circuit for detecting the temperature inside the lamp, and when the temperature is within a temperature range from a first set temperature to a second set temperature, the applied current has a relational characteristic that changes in accordance with the level of the temperature;
The light source current control unit inputs a sensor signal from the temperature sensor, and when the temperature acquired by the sensor signal is within a temperature range from the first set temperature to the second set temperature, determines that the current applied to the light source is changing. The vehicular lamp according to any one of claims 1 to 3 ,
The light source current control unit uses a passing operation sensor and determines that a passing operation has been performed when a lever operation of pulling an operating lever of a light switch toward oneself is detected. The vehicular lamp according to claim 1 ,
The light source current control unit sets the set time from when the flashing operation is performed to a first set time determined based on a required time when the flashing operation is performed multiple times. The vehicular lamp according to claim 1 ,
the light source current control unit sets the set time from the occurrence of the passing operation as a second set time determined based on a required time from the occurrence of a first passing operation to the occurrence of a second passing operation when passing operations are performed consecutively,
When the current applied to the light source is fixed due to the passing operation, if the next passing operation occurs before the second set time has elapsed, the remaining time is reset to the second set time from the time of the next passing operation.