Light Source Module

Abstract

To provide a vehicle light source module.SOLUTION: A light source module 100 can switch between high beam and low beam and is mounted on a vehicle. A first light source 110 is arranged such that the emitted light is emitted onto a low beam region 12 by a first optical system 4. A second light source 120 is arranged such that the emitted light is emitted onto a high beam region 14 by a second optical system 6. A lighting circuit 130 supplies a drive current IOUT to the first light source 110 in response to a high beam or low beam lighting instruction, and supplies a drive current IOUT to the second light source 120 in response to a high beam lighting instruction.SELECTED DRAWING: Figure 17

Description

[Technical Field]

[0001] The present invention relates to a lamp for use in a vehicle such as a motorcycle. [Background technology]

[0002] In conventional motorcycles, the high beam and low beam light sources are driven separately by two independent lighting circuits. Similar configurations are often used in vehicles other than motorcycles. This makes the lamp structure complex and maintenance time-consuming. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-069150 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in light of this situation, and one exemplary purpose of an embodiment of the present invention is to provide a light source module for a vehicle. [Means for solving the problem]

[0005] 1. One aspect of the present invention relates to a light source module for a vehicle that can switch between high beam and low beam. The light source module includes a first light source arranged so that its emitted light is irradiated onto a low beam area by a first optical system, a second light source arranged so that its emitted light is irradiated onto a high beam area by a second optical system, and a lighting circuit configured to supply a drive current to the first light source in response to an instruction to turn on either high beam or low beam, and to supply a drive current to the second light source in response to an instruction to turn on high beam.

[0006] The first light source and the second light source may be connected in series. The lighting circuit may include a drive circuit that supplies a drive current to the series-connected circuit of the first light source and the second light source, and a bypass switch that is provided in parallel with the second light source and is turned off when a high beam is instructed to be turned on and turned on when a low beam is instructed to be turned on.

[0007] The drive circuit may reduce the drive current when the bypass switch is on compared to when it is off, thereby suppressing increases in power consumption and heat generation when the high beams are on.

[0008] The first light source and the second light source may be mounted side by side in a predetermined direction on a plane perpendicular to the ground. The first optical system and the second optical system may be lens optical systems. The predetermined direction may be horizontal.

[0009] The first light source may include a first semiconductor light-emitting element and a second semiconductor light-emitting element. The second light source may include a third semiconductor light-emitting element. The first optical system may include a first lens that receives light emitted from the first semiconductor light-emitting element and forms a light distribution in an area below an elbow point in the low beam area, and a second lens that receives light emitted from the second semiconductor light-emitting element and forms a light distribution in an area above the elbow point in the low beam area. The second optical system may include a third lens that receives light emitted from the third semiconductor light-emitting element and illuminates the high beam area.

[0010] The first light source may be mounted on a first surface parallel to the ground, and the second light source may be mounted on a third surface opposite to the first surface. The first optical system may include a first reflector provided on the first surface side. The second optical system may include a second reflector provided on the third surface side.

[0011] The first light source may be mounted on a first surface parallel to the ground, and the second light source may be mounted on a second surface perpendicular to the ground. The first optical system may include a reflective optical system. The second optical system may include a transmissive optical system.

[0012] The first light source may include a plurality of light-emitting elements arranged adjacent to each other in the horizontal direction.

[0013] The light source module may further include a third light source arranged so that emitted light from the third light source is irradiated onto the low beam area by the first optical system. The lighting circuit may be configured to supply a drive current to the third light source in response to an instruction to turn on the low beam.

[0014] The lighting circuit may include a first switch that is turned on in response to a low beam lighting instruction, a second switch that is turned on in response to a high beam lighting instruction, and a drive circuit that generates a drive current. The first light source, the third light source, and the first switch may be connected in series, and the second light source and the second switch may be connected in parallel with the third light source and the first switch.

[0015] The first light source and the third light source may be mounted on a first surface parallel to the ground, the second light source may be mounted on a third surface opposite to the first surface, the first optical system may include a first reflector provided on the first surface side, and the second optical system may include a second reflector provided on the third surface side.

[0016] The first light source and the third light source are mounted on a first surface parallel to the ground, the second light source is mounted on a second surface perpendicular to the ground, and the first optical system may include a reflective optical system. The second optical system may include a transmissive optical system.

[0017] The first light source and the third light source may each include a plurality of light-emitting elements arranged adjacent to each other in the horizontal direction.

[0018] The second light source may include a plurality of light emitting elements arranged adjacent to each other in the horizontal direction.

[0019] Another aspect of the present invention also relates to a light source module for a vehicle that can switch between high beam and low beam. The light source module includes a first light source arranged so that its emitted light is irradiated onto a low beam region by a first optical system, a second light source arranged so that its emitted light is irradiated onto a high beam region by a second optical system, the second optical system that irradiates the light emitted from the second light source onto the high beam region, a heat sink thermally coupled to the first light source and the second light source, and a lighting circuit that supplies drive current to the first light source and the second light source.

[0020] The light source module may further include a third light source arranged so that light emitted from the third light source is irradiated onto the low beam area by the first optical system.

[0021] One aspect of the present invention relates to a light source module for a vehicle that can switch between high beam and low beam. The light source module includes a first light source for low beam, a first switch connected in parallel to the first light source, a second light source and a second switch for low beam connected in series to the first light source, a third light source and a third switch for high beam connected in series in a path parallel to the second light source and the second switch, and a drive circuit that generates a drive current in response to an instruction to turn on either high beam or low beam.

[0022] According to this embodiment, high beam and low beam can be switched by a single drive circuit. Also, if a disconnection occurs in one of the paths, the combination of on / off of the first switch to the third switch is changed to supply the drive current to the path where the disconnection does not occur, thereby allowing the illumination ahead of the vehicle to continue.

[0023] The light source module may further include a controller that, under normal operation, (i) turns off the first switch, turns on the second switch, and turns off the third switch in response to an instruction to turn on the low beam, and (ii) turns off the first switch, turns off the second switch, and turns on the third switch in response to an instruction to turn on the high beam.

[0024] When the controller detects the current interruption, the controller may turn on the first switch, thereby diverting the drive current to the first switch when the first light source is disconnected, allowing the drive current to continue to be supplied to the second light source or the third light source, and allowing the area ahead of the vehicle to continue to be illuminated.

[0025] The controller may turn off the first switch when a current interruption is detected continuously for a predetermined first time period after turning on the first switch. If the current interruption is not resolved even when the first switch is turned on, it is estimated that the break is not in the first light source. In this case, turning off the first switch allows the first light source to be turned on, thereby suppressing a decrease in illuminance in the low beam area.

[0026] The first time period may be 2 ms to 500 ms. With such a short time, driving can be continued even if visibility becomes dark.

[0027] The controller may determine that the current is interrupted when the drive current remains zero for a predetermined second time period, thereby preventing false detection due to noise.

[0028] The controller may turn on the second switch while the first switch is fixed in the on state, regardless of whether a high beam or low beam is turned on. This disables manual switching between high beam and low beam, thereby notifying the driver of the open circuit fault. In addition, the low beam is fixed, preventing glare to surrounding traffic participants.

[0029] While the first switch is fixed in the on state, the controller may turn on the third switch regardless of the instruction to turn on the high beam or low beam. This disables manual switching between high beam and low beam, making it possible to notify the driver of the wire breakage fault. In addition, since people generally drive with low beam more often than not, the driver will be more likely to notice the wire breakage fault by only enabling the high beam and disabling the low beam.

[0030] Any combination of the above components or mutual substitution of the components or expressions of the present invention between methods, devices, systems, etc. are also valid aspects of the present invention. [Effects of the Invention]

[0031] According to one aspect of the present invention, a light source module that integrates high beam and low beam can be provided. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a diagram showing a headlamp equipped with a light source module according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing an example of a layout of a headlamp. [Figure 3] FIG. 10 is a perspective view showing another example of a headlamp layout. [Figure 4] FIG. 10 is a perspective view showing yet another example of a headlamp layout. [Figure 5] FIG. 5 is a diagram showing the light distribution formed by the headlamp of FIG. 4. [Figure 6] 10 is a diagram showing a headlamp equipped with a light source module according to a second embodiment. FIG. [Figure 7] 7 is an operational waveform diagram of the light source module of FIG. 6. [Figure 8] 8(a) and 8(b) are diagrams illustrating an example of control of the drive current IOUT. [Figure 9] 10A and 10B are diagrams illustrating advantages of dimming by analog dimming. [Figure 10] FIG. 2 is a circuit diagram of the light source module. [Figure 11] FIG. 2 is a circuit diagram showing a configuration example of a drive circuit. [Figure 12] FIG. 10 is a circuit diagram of a light source module according to a modified example. [Figure 13] FIG. 7 is a perspective view showing an example of the layout of the headlamp of FIG. 6. [Figure 14] FIG. 10 is a diagram showing a headlamp equipped with a light source module according to a third embodiment. [Figure 15] FIG. 2 is a perspective view showing an example of a layout of a headlamp. [Figure 16] FIG. 10 is a perspective view showing another example of the layout of the headlamp and the light source module. [Figure 17] FIG. 10 is a diagram showing a headlamp for a motorcycle according to a fourth embodiment. [Figure 18] 10 is a flowchart illustrating the operation of the light source module. [Figure 19] FIG. 4 is a first operational waveform diagram of the light source module. [Figure 20] FIG. 10 is a second operational waveform diagram of the light source module. [Figure 21] FIG. 10 is a third operational waveform diagram of the light source module. [Figure 22] FIG. 4 is a fourth operational waveform diagram of the light source module. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. Furthermore, the embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0034] In this specification, "a state in which component A is connected to component B" includes not only a case in which component A and component B are directly physically connected to each other, but also a case in which component A and component B are indirectly connected to each other via other components that do not substantially affect the electrical connection between them or that do not impair the function or effect achieved by their connection.

[0035] Similarly, "a state in which component C is provided between component A and component B" includes not only cases in which components A and C, or components B and C, are directly connected, but also cases in which they are indirectly connected via other components that do not substantially affect the electrical connection state between them or impair the functions or effects achieved by their combination.

[0036] In addition, in this specification, symbols attached to electrical signals such as voltage signals and current signals, or circuit elements such as resistors and capacitors, represent the respective voltage values, current values, resistance values, and capacitance values ​​as necessary.

[0037] (Embodiment 1) 1 is a diagram showing a headlamp 2A equipped with a light source module 100 according to embodiment 1. The headlamp 2A is mounted on a motorcycle, is switchable between high beam and low beam, and includes the light source module 100, a first optical system 4, and a second optical system 6.

[0038] The light source module 100 is modularized and includes a first light source 110, a second light source 120, a lighting circuit 130, and a heat sink (not shown). The first light source 110 is positioned so that its emitted light is irradiated onto a low beam area 12 on a virtual vertical screen by a first optical system 4. The second light source 120 is positioned so that its emitted light is irradiated onto a high beam area 14 by a second optical system 6. The first light source 110 and the second light source 120 each include at least one semiconductor light emitting element, such as an LED (light emitting diode), an LD (laser diode), or an organic EL element.

[0039] A high beam or low beam lighting instruction is input from the vehicle side to the light source module 100. When a lighting instruction for either high beam or low beam is input, the lighting circuit 130 supplies a driving current I OUT In addition, the lighting circuit 130 supplies the second light source 120 with a driving current I in response to a high beam lighting instruction. OUT The system is configured to supply

[0040] In this embodiment, the first light source 110 and the second light source 120 are connected in series, and the lighting circuit 130 includes a drive circuit 132, which is a constant current driver, and a bypass switch 134. The drive circuit 132 is enabled in the high beam or low beam lighting state, and supplies a drive current I to the series connection circuit of the first light source 110 and the second light source 120. OUT supply.

[0041] The bypass switch 134 is provided in parallel with the second light source 120, and is turned off during a high beam illumination command and turned on during a low beam illumination command.

[0042] In this embodiment, the first light source 110 includes two LEDs, and the second light source 120 includes one LED. Therefore, a total of three LEDs are connected in series on the drive path of the drive circuit 132. Generally, the voltage V of the battery 10 of a motorcycle is BAT , that is, the power supply voltage of the drive circuit 132 is 12 V. On the other hand, since the forward voltage of the white LED is about 3.5 V, the voltage across the load of the drive circuit 132 is about 3.5 V × 3 = 10.5 V, and the battery voltage V BAT Therefore, the drive circuit 132 can be configured with a step-down switching converter or a linear regulator.

[0043] The above is the configuration of the light source module 100. Next, the operation thereof will be described.

[0044] When neither a high beam nor a low beam is turned on, the drive circuit 132 is disabled, and the drive current I OUT is not generated.

[0045] When a command to turn on either the high beam or low beam is issued, the drive circuit 132 is enabled, and a drive current I stabilized at a predetermined current amount is supplied. OUT is generated.

[0046] While a low beam lighting command is issued, the bypass switch 134 is on and the drive current IOUT flows to the first light source 110 and the bypass switch 134. Therefore, the second light source 120 is turned off, and only the first light source 110 is turned on, and the low beam area 12 is illuminated.

[0047] While a high beam lighting command is issued, the bypass switch 134 is off and the driving current I OUT flows to the first light source 110 and the second light source 120. Therefore, the first light source 110 and the second light source 120 are turned on, and both the low beam area 12 and the high beam area 14 are illuminated.

[0048] 2 is a perspective view showing an example of the layout of a headlamp 2A. The first light source 110 is mounted on a first surface S1 parallel to the ground. The second light source 120 is mounted on a second surface S2 perpendicular to the ground. The first surface S1 and the second surface S2 correspond to the surfaces of a block-shaped heat sink 8.

[0049] Preferably, the two light emitting elements that make up the first light source 110 are arranged side by side in the horizontal direction, which makes it easier to create a horizontal cut line that is the boundary between the high beam and the low beam.

[0050] The first optical system 4 includes a reflective optical system, i.e., a mirror. The second optical system 6 includes a transmissive optical system, i.e., a lens. The lighting circuit 130 is mounted on a heat sink 8. For example, the heat sink 8 may have a cavity or recess therein, and the lighting circuit 130 may be fixed in close contact with this cavity or recess.

[0051] 3 is a perspective view showing another example of the layout of the headlamp 2A. The first light source 110 is mounted on a first surface S1 parallel to the ground. The second light source 120 is mounted on a third surface S3 opposite the first surface S1. The first optical system 4 includes a first reflector provided on the first surface S1 side, and the second optical system 6 includes a second reflector provided on the third surface S3 side.

[0052] 3, the two light emitting elements that make up the first light source 110 are also arranged side by side in the horizontal direction, which makes it easier to create a horizontal cut line that is the boundary between the high beam and the low beam.

[0053] 4 is a perspective view showing yet another example of the layout of a headlamp 2A. The headlamp 2A includes a light source module 100 and a lens module 150. The light source module 100 includes a first light source 110, a second light source 120, a lighting circuit 130, a heat sink 140, a printed circuit board 142, and a connector 144. The first light source 110 includes a first semiconductor light emitting element 112A and a second semiconductor light emitting element 112B, and the second light source 120 includes a third semiconductor light emitting element 122.

[0054] The first semiconductor light emitting element 112A, the second semiconductor light emitting element 112B, and the third semiconductor light emitting element 122 are mounted on the heat sink 140 and aligned in a predetermined direction. In this example, the predetermined direction is the horizontal direction. The arrangement order of the first semiconductor light emitting element 112A, the second semiconductor light emitting element 112B, and the third semiconductor light emitting element 122 may be reversed. The anode electrode and the cathode electrode of each of the first semiconductor light emitting element 112A, the second semiconductor light emitting element 112B, and the third semiconductor light emitting element 122 are formed on their surfaces.

[0055] Components of the lighting circuit 130 and a connector 144 are mounted on the printed circuit board 142. In addition, the wiring of the printed circuit board 142 is connected to the electrodes of the first semiconductor light emitting element 112A, the second semiconductor light emitting element 112B, and the third semiconductor light emitting element 122 via bonding wires.

[0056] The lens module 150 includes a first lens 152 and a second lens 154 corresponding to the first optical system 4, and a third lens 156 corresponding to the second optical system 6. The first lens 152 receives the beam emitted from the first semiconductor light emitting element 112A and projects it ahead of the vehicle. The second lens 154 receives the beam emitted from the second semiconductor light emitting element 112B and projects it ahead of the vehicle. The third lens 154 receives the beam emitted from the third semiconductor light emitting element 122 and projects it ahead of the vehicle.

[0057] Fig. 5 is a diagram showing the light distribution formed by the headlamp 2A of Fig. 4. The dashed-dotted line indicates the cutoff line CL, and a low-beam light distribution is formed below the cutoff line CL, and a high-beam light distribution is formed above the cutoff line CL.

[0058] The low beam region includes a first portion L1 below a horizontal line passing through elbow point ELB and a second portion L2 above it. First lens 152 forms a light distribution A1 that mainly covers first portion L1, and second lens 154 forms a light distribution A2 that mainly covers second portion L2. Third lens 156 forms a light distribution A3 that covers high beam region H.

[0059] (Embodiment 2) In the first embodiment, the driving current I generated by the driving circuit 132 OUT was constant regardless of the lighting mode (low beam, high beam) of the headlamp 2A. Therefore, the power consumption, i.e., the heat generation, in high beam mode is greater than the power consumption, i.e., the heat generation, in low beam mode. Specifically, as shown in FIG. 1, if the first light source 110 includes two LED chips and the second light source 110 includes one LED chip, the amount of heat generated in high beam mode is 1.5 times the amount of heat generated in low beam mode. This may result in a larger heat sink.

[0060] 6 is a diagram showing a headlamp 2C including a light source module 100C according to embodiment 2. The configuration of the light source module 100C will be described, focusing on differences from the light source module 100 of embodiment 1.

[0061] The lighting circuit 130C includes a drive circuit 132C and a bypass switch 134. In this embodiment, the drive circuit 132C controls the drive current I OUT Specifically, the driving current I in the high beam mode is OUT The amount of current I OUTH, the driving current in low beam mode I OUT The amount of current I OUTL Make it smaller than. I OUTH OUTL

[0062] Assume that the first light source 110 includes two semiconductor light emitting elements 112A and 112B, and the second light source 120 includes one semiconductor light emitting element 122. In this case, I OUTH I OUTL If the power consumption is set to about 2 / 3 of the normal power consumption, the power consumption in high beam mode can be reduced to the same level as that in low beam mode. OUTH I OUTL It may be greater than 2 / 3 times the value of I. OUTH is 2 / 3 x I OUTL The larger the value, the higher the illuminance in high beam mode, but the smaller the effect of reducing power consumption.

[0063] Furthermore, as a result of the reduction in power consumption, i.e., the amount of heat generated, it becomes possible to make the heat sink smaller or to replace it with a simpler cooling mechanism.

[0064] FIG. 7 is an operational waveform diagram of the light source module 100 of FIG. 6. When the high beam and low beam are turned off, the driving current I OUT is zero. During the low beam lighting period, the driving current I OUT The time average quantity of the first current I OUTL During the high beam lighting period, the driving current I OUT The time average quantity of the second current I OUTH decreases to.

[0065] Figures 8(a) and 8(b) show the drive current I OUT As shown in FIG. 8(a), in the high beam mode, analog dimming (current dimming) is used to control the driving current I OUT The amount of current may be reduced.

[0066] Figure 9 is a diagram illustrating the advantages of dimming with analog dimming. The horizontal axis represents the drive current I​OUT The vertical axis indicates the amount of light emitted by one light-emitting element. L is the operating point of the low beam mode, and P H indicates the operating point of the high beam mode. As shown in Figure 9, the luminous efficiency of the LED increases with the driving current I OUT Therefore, the drive current I OUT to 2 / 3 times (66.7%), the LED light output will not drop to 2 / 3, but will remain at, say, 3 / 4 times (75%). Therefore, the total light output in high beam mode will be 0.75 x 3 / 2 = 1.125 times the total light output in low beam mode, a slight increase.

[0067] As shown in Figure 8(b), in high beam mode, PWM (pulse width modulation) dimming is used to control the driving current I OUT If the white light source is composed of a blue LED and a yellow phosphor, the driving current I OUT The emitted color changes depending on the light source. Therefore, when analog dimming is used, the chromaticity may change between low beam and high beam. If you want to suppress the chromaticity change, you can use PWM dimming to make the chromaticity of low beam and high beam consistent.

[0068] 10 is a circuit diagram of the light source module 100C. The lighting circuit 130C includes a drive circuit 132C and a bypass switch 134.

[0069] A lighting command H / L is input to the lighting circuit 130C from an external circuit. The lighting command H / L assumes a first state in low beam mode and a second state in high beam mode. For example, if the external circuit has an open-collector / open-drain output stage, the first state of the lighting command H / L may be high impedance (open) and the second state may be low level. When the lighting command H / L is in the first state (high impedance), the base of the transistor Q12 is pulled up by the resistor R15, so that the transistor Q12 is turned off. When the lighting command H / L is in the second state (low level), the transistor Q12 is turned on. The external circuit that generates the lighting command H / L may have a push-pull output stage, in which case the first state of the lighting command H / L may be high level and the second state may be low level.

[0070] The drive circuit 132 is a constant current driver that generates a drive voltage between the positive output OUTP and the negative output OUTN, and outputs a drive current I stabilized to a target current. OUT In this example, the drive current I OUT Specifically, the drive circuit 132 has a dimming terminal DIM, and changes the drive current I OUT The target value is the dimming voltage V input to the dimming terminal DIM. ADIM It changes depending on I OUT =K×V ADIM

[0071] The drive circuit 132 is connected to a reference voltage V REF Resistors R11 and R12 and a transistor Q11 are connected in series between the VREF terminal and ground.

[0072] The drive circuit 132 also receives the power supply voltage V DD The bypass switch 134 includes resistors R13 and R14 and transistors Q13 and Q14. The resistors R13 and R14 and the transistor Q13 form the gate driver of the bypass transistor Q14.

[0073] The operation of the light source module 100C in FIG. 10 will be described. Low beam mode When the lighting command H / L is in the first state (high impedance or high level), the transistor Q12 is off and the base of the transistor Q13 is low, so that the transistor Q13 is off and the bypass transistor Q14 is on, and therefore the driving current I OUT is not supplied.

[0074] When the lighting command H / L is in the first state, the transistor Q12 is off and the base of the transistor Q1 is low, so the transistor Q11 is off and the voltage V at the dimming terminal DIM of the drive circuit 132 ADIM is the reference voltage V REF At this time, the driving current I OUT is the reference voltage V REF Target quantity I proportional to OUTL is stabilized to I OUTL =K×V ADIM =K×V REF

[0075] High beam mode When the lighting command H / L is in the second state (low level), the transistor Q12 is turned on and a current is supplied to the base of the transistor Q13, so that the transistor Q13 is turned on and the bypass transistor Q14 is turned off, so that the driving current I OUT is supplied.

[0076] When the lighting command H / L is in the second state (low level), the transistor Q12 is turned on and a current is supplied to the base of the transistor Q11. Therefore, the transistor Q11 is turned on and the dimming terminal DIM of the drive circuit 132 is supplied with the divided reference voltage V REF is the dimming voltage V ADIM is entered as V ADIM =R12 / (R11+R12)×V REF At this time, the drive current I OUT Target amount of IOUTH is expressed by the following formula: I OUTH =K×V ADIM =K×R12 / (R11+R12)×V REF =R12 / (R11+R12)×I OUTL In other words, the dimming rate can be set according to the voltage division ratio of resistors R11 and R12.

[0077] 11 is a circuit diagram showing an example of the configuration of the drive circuit 132. The drive circuit 132 is a polarity inverting converter, and outputs a ground voltage of 0V from the positive output OUTP and a negative voltage of −V OUT Output.

[0078] The drive circuit 132 includes transistors M11 and M12, an inductor L11, a capacitor C11, and a controller 136. The controller 136 controls a drive current I OUT Current detection signal V according to CS is the analog dimming voltage V input to the dimming terminal DIM ADIM The control method or mode of the controller 136 is not particularly limited, and may be a current mode control method or a current detection signal V CS The ripple control method may be a ripple control method that targets the above. Ripple control methods include hysteresis control (bang-bang control), bottom detection method, peak detection method, and the like.

[0079] The transistors M11 and M12 may be integrated on the same chip as the controller 136. The drive circuit 132 also includes a reference voltage source 160 and a power supply circuit 162. The reference voltage source 160 generates a reference voltage V REF The power supply circuit 162 generates a negative output (-V OUT ) with respect to the power supply voltage V DD At least one of the reference voltage source 160 and the power supply circuit 162 may be built into the controller 136.

[0080] 11 is also applicable to the first and third embodiments.

[0081] Fig. 12 is a circuit diagram of a light source module 100D according to a modified example. In addition to the lighting circuit 130C of Fig. 10, the lighting circuit 130D includes a temperature derating circuit 138. The temperature derating circuit 138 includes an NTC (Negative Temperature Coefficient) thermistor 139, resistors R21 and R22, and transistors Q21 and Q22.

[0082] Resistor R21 and thermistor 139 provide a reference voltage V REF The temperature detection voltage V TEMP The voltage V at the dimming terminal DIM is generated by the transistor Q21, resistor R22, and transistor Q22. ADIM is the temperature detection voltage V TEMP The higher the temperature rises, the lower the temperature detection voltage V TEMP decreases, and the voltage V at the dimming terminal DIM ADIM As a result, the drive current I OUT decreases and temperature derating is applied.

[0083] FIG. 13 is a perspective view showing an example of the layout of the headlamp 2C of FIG. 6. The basic configuration of the headlamp 2C is similar to that of FIG. 4, so only the differences will be described. As described above, the headlamp 2C of embodiment 2 can reduce power consumption in high beam mode, thereby simplifying the cooling structure of the first light source 110 and the second light source 120. Therefore, the heat sink 140 of FIG. 6 is replaced with a thin heat dissipation plate 146 in FIG. 13. This allows the light source module 100 to be made smaller and less expensive.

[0084] (Embodiment 3) 14 is a diagram showing a headlamp 2B equipped with a light source module 200 according to embodiment 3. As in embodiment 1, the headlamp 2B is mounted on a motorcycle, is switchable between high beam and low beam, and includes the light source module 200, a first optical system 4, a second optical system 6, and a heat sink (not shown).

[0085] The light source module 200 is modularized and includes a first light source 210, a second light source 220, a third light source 230, and a lighting circuit 240. The first light source 210 and the third light source 230 are arranged so that their respective emitted light is irradiated onto the low beam region 12 on a virtual vertical screen by the first optical system 4. The second light source 220 is arranged so that its emitted light is irradiated onto the high beam region 14 by the second optical system 6.

[0086] Each of the first light source 210, the second light source 220, and the third light source 230 includes at least one semiconductor light emitting element, such as an LED (light emitting diode), an LD (laser diode), or an organic EL element. For the same reason as in the first embodiment, the number of LEDs connected in series is three, which allows the drive circuit 242 to be configured with a step-down converter or a linear regulator.

[0087] A high beam or low beam lighting instruction is input from the vehicle side to the light source module 200. The lighting circuit 240 supplies a driving current I to the first light source 210 regardless of whether the high beam or low beam lighting instruction is input. OUT In addition, the lighting circuit 240 supplies the second light source 220 with a driving current I in response to a high beam lighting instruction. OUT In addition, the lighting circuit 240 is configured to supply a driving current I to the third light source 230 in response to a lighting instruction for the low beam. OUT The system is configured to supply

[0088] In this embodiment, the lighting circuit 240 includes a drive circuit 242, which is a constant current driver, a first switch 244, and a second switch 246. The drive circuit 242 is enabled in the high beam or low beam lighting state, and a drive current I OUT Generate.

[0089] The first switch 244 is provided in series with the third light source 230, and the second switch 246 is provided in series with the second light source 220. The first switch 244 is turned on in response to an instruction to turn on the low beam. The second switch 246 is turned on in response to an instruction to turn on the high beam.

[0090] The above is the configuration of the light source module 200. Next, the operation thereof will be described.

[0091] When neither a high beam nor a low beam is turned on, the drive circuit 242 is disabled and the drive current I OUT is not generated.

[0092] When a command to turn on either the high beam or low beam is issued, the drive circuit 242 is enabled, and a drive current I stabilized at a predetermined current amount is supplied. OUT is generated.

[0093] While a low beam lighting command is being issued, the first switch 244 is on, the second switch 246 is off, and the driving current I OUT flows through the path of the first light source 210, the third light source 230, and the first switch 244. Therefore, the first light source 210 and the third light source 230 are turned on, the second light source 220 is turned off, and the low beam area 12 is illuminated.

[0094] While a high beam lighting command is being issued, the first switch 244 is off, the second switch 246 is on, and the driving current I OUT flows through the path of the first light source 210, the second light source 220, and the second switch 246. Therefore, the first light source 210 and the second light source 220 are turned on, and the third light source 230 is turned off. At this time, the high beam area 14 is illuminated, and the low beam area 12 can be illuminated with lower illuminance than when the low beam is on.

[0095] 15 is a perspective view showing an example of the layout of a headlamp 2B. The first light source 210 and the third light source 230 are mounted on a first surface S1 parallel to the ground. The second light source 220 is mounted on a second surface S2 perpendicular to the ground. The first surface S1 and the second surface S2 correspond to the surfaces of a block-shaped heat sink 8.

[0096] Preferably, the three light-emitting elements constituting the first light source 210 and the third light source 230 are arranged side by side in the horizontal direction. This makes it easier to create a horizontal cut-off line that is the boundary between the high beam and the low beam. For example, the light-emitting element of the first light source 210 may be arranged in the center, and the two light-emitting elements of the third light source 230 may be arranged to sandwich it.

[0097] The first optical system 4 includes a reflective optical system, i.e., a mirror, and the second optical system 6 includes a transmissive optical system, i.e., a lens.

[0098] 16 is a perspective view showing another example of the layout of the headlamp 2B and the light source module 200. The first light source 210 and the third light source 230 are mounted on a first surface S1 parallel to the ground. The second light source 220 is mounted on a third surface S3 opposite the first surface S1. The first optical system 4 includes a first reflector provided on the first surface S1 side, and the second optical system 6 includes a second reflector provided on the third surface side.

[0099] 16, the three light-emitting elements constituting the first light source 210 and the third light source 230 are also arranged side by side in the horizontal direction. Similarly, the two light-emitting elements constituting the second light source 22 are also arranged side by side in the horizontal direction. This makes it easier to create a horizontal cut-off line that is the boundary between the high beam and the low beam.

[0100] Although the above description has been given of a lamp for a motorcycle, the application of the present invention is not limited to this, and it can also be applied to vehicles such as four-wheeled automobiles and trucks.

[0101] 17 is a diagram showing a motorcycle headlamp 2 according to embodiment 4. The headlamp 2 is switchable between high beam and low beam, and includes a light source module 300, a first optical system 4, and a second optical system 6.

[0102] The light source module 300 is modularized and includes an LED string 302 and a lighting circuit 400. The LED string 302 includes a first light source 310 and a second light source 320 that are light sources for low beam, and a third light source 330 that is a light source for high beam. The light emitted from the first light source 310 and the second light source 320 is irradiated onto the low beam region 22 on the virtual vertical screen 20 by the first optical system 4. The light emitted from the third light source 330 is irradiated onto the high beam region 24 by the second optical system 6.

[0103] Each of the first light source 310, the second light source 320, and the third light source 330 includes at least one semiconductor light emitting element, for example, an LED (light emitting diode). Note that an LD (laser diode) or an organic EL element may also be used as the semiconductor light emitting element.

[0104] In this embodiment, the first light source 310 includes one LED, and the second light source 320 and the third light source 330 each include two LEDs. Therefore, a total of three LEDs are connected in series on the drive path of the drive circuit 410. Generally, the voltage V of the battery 10 of a motorcycle is BAT , that is, the power supply voltage of the drive circuit 410 is 12 V. On the other hand, since the forward voltage of the white LED is about 3.5 V, the voltage across the load of the drive circuit 410 is about 3.5 V × 3 = 10.5 V, and the battery voltage V BAT Therefore, the drive circuit 410 can be configured with a step-down switching converter or a linear regulator.

[0105] The light source module 300 is connected to a battery voltage V BAT In addition, a high beam or low beam lighting command is input from the vehicle side. The lighting circuit 400 controls the driving current I OUTand controls the turning on and off of the first light source 310, the second light source 320, and the third light source 330.

[0106] The lighting circuit 400 includes a drive circuit 410, a first switch SW1, a second switch SW2, a third switch SW3, and a controller 420.

[0107] The first switch SW1 is provided in parallel with the first light source 310. The second light source 320 and the second switch SW2 are connected in series. The third light source 330 and the third switch SW3 are provided in series on a path parallel to the second light source 320 and the second switch SW2.

[0108] The drive circuit 410 is a constant current output driver, and is enabled in response to a lighting instruction for either high beam or low beam, and outputs a drive current I stabilized at a predetermined current amount. OUT Generate.

[0109] The controller 420 controls the on / off of the first switch SW1 to the third switch SW3 according to the instruction to turn on the high beam or low beam and whether or not the current is cut off.

[0110] The controller 420 is configured to be able to detect a current interruption caused by a break in the LED string including the first light source 310, the second light source 320, and the third light source 330. For example, the controller 420 detects an output current I OUT , and the drive circuit 410 is enabled, but the drive current I OUT When no current is flowing, it is determined that the current is interrupted. A state in which no current interruption is detected is called a normal state.

[0111] For example, the controller 420 may be configured to supply a predetermined amount of drive current I OUTIf the state where no current is flowing continues for a predetermined second time T2, it is determined that a current interruption state has occurred. The second time T2 may be set, for example, between 2 ms and 500 ms. Setting the second time T2 longer than 2 ms prevents false detection of the current interruption state due to noise, while setting the second time T2 shorter than 500 ms enables the current interruption state to be detected in a short time. Furthermore, by using the following process, when the headlamps are turned back on, the time the headlamps remain off can be kept to 500 ms or less, ensuring safety.

[0112] In a normal state, the controller 420 keeps the first switch SW1 fixedly off. In addition, in a normal state, the controller 420 (i) turns on the second switch SW2 and turns off the third switch SW3 in response to an instruction to turn on the low beam. As a result, the drive current I generated by the drive circuit 410 OUT flows through a path including the first light source 310, the second light source 320, and the second switch SW2. At this time, the first light source 310 and the second light source 320 are turned on, and the low beam area 22 is illuminated.

[0113] In a normal state, the controller 420 turns off the second switch SW2 and turns on the third switch SW3 in response to a high beam lighting instruction (ii). As a result, the drive current I OUT flows through a path including the first light source 310, the third light source 330, and the third switch SW3. At this time, the first light source 310 and the third light source 330 are turned on, the high beam area 24 is illuminated, and the low beam area 22 is illuminated with an illuminance lower than that during low beam.

[0114] Next, the control in the event of a wire breakage will be described.

[0115] When the controller 420 detects a current interruption state, the controller 420 turns on the first switch SW1. If a break occurs in the first light source 310 of the LED string 302, the first switch SW1 turns on, and the driving current I OUT starts to flow again, and the current blocking state is resolved. Therefore, the driving current IOUT is bypassed to the first switch SW1, and the driving current I OUT This allows the light source to continue to supply light to the front of the vehicle.

[0116] If a break occurs in the LED string 302 at a location other than the first light source 310, even if the first switch SW1 is turned on, the drive current I OUT Therefore, when the current interruption state continues for a predetermined first time T1 after the first switch SW1 is turned on, the controller 420 determines that the break is in a location other than the first light source 310, and turns off the first switch SW1.

[0117] 18 is a flowchart illustrating the operation of the light source module 300. When a low beam or high beam illumination command is issued (S100), the first switch SW1 to the third switch SW3 are set to states corresponding to the illumination command (S102). Specifically, the first switch SW1 is off, and in the case of a low beam illumination command, the second switch SW2 is on and the third switch SW3 is off, and in the case of a high beam illumination command, the second switch SW2 is off and the third switch SW3 is on. In this state, the drive circuit 410 is enabled, and the drive current I OUT is generated (S104).

[0118] The controller 420 monitors whether or not there is a current interruption (S106). During a normal state (N in S106), the low beams are maintained on. If a current interruption is detected (Y in S106), the first switch SW1 is turned on (S108). Then, the presence or absence of a current interruption is re-determined (S110). If the current interruption has been resolved (N in S110), the first switch SW1 is maintained on. If the current interruption has not been resolved (Y in S110), the first switch SW1 is turned off.

[0119] FIG. 19 is a first operational waveform diagram of the light source module 300. FIG. 19 shows a state in which a wire breakage fault occurs in the first light source 310 while the low beam is on. The state is normal before time t2. At time t0, an instruction to turn on the low beam is issued. At time t1, the second switch SW2 is turned on, and the drive circuit 410 supplies the drive current I OUT is generated.

[0120] At time t2, when a wire break occurs in the first light source 310, the driving current I OUT If this state continues for a second time T2, it is determined that the current is interrupted at time t3, and the first switch SW1 is turned on. When the first switch SW1 is turned on, the disconnected portion is bypassed, and the drive current I OUT The light will start flowing again and the low beams will remain on, but the brightness of the low beams will be lower than normal.

[0121] Fig. 20 is a second operational waveform diagram of the light source module 300. Fig. 20 shows a state in which a disconnection fault occurs in the second light source 320 while the low beam is on. The operation from time t0 to t2 is the same as that in Fig. 19.

[0122] At time t2, when a disconnection fault occurs in the second light source 320, the driving current I OUT is cut off. If this state continues for a second time T2, at time t3 it is determined that the current is cut off, and the first switch SW1 is turned on. Even when the first switch SW1 is turned on, the broken point is not bypassed, so the current is cut off. Then, at time t4, the first time T1 has elapsed since the first switch SW1 was turned on, the first switch SW1 is turned off.

[0123] Drive current I OUT If the disconnection state continues, the driver will notice an abnormality in headlamp 2 because visibility will become dark. When the driver switches from low beam to high beam at time t5, second switch SW2 will be turned off and third switch SW3 will be turned on. Then, the disconnected part will no longer be used, and the drive current I OUT will start flowing again and headlamp 2 can continue to be used as a high beam.

[0124] FIG. 21 is a third operational waveform diagram of the light source module 300. FIG. 21 shows a state in which a wire breakage fault occurs in the first light source 310 while the high beam is on. The state is normal before time t2. An instruction to turn on the high beam is issued at time t0. At time t1, the third switch SW3 is turned on, and the drive circuit 410 supplies the drive current I OUT is generated.

[0125] At time t2, when a wire break occurs in the first light source 310, the driving current I OUT If this state continues for a second time T2, it is determined that the current is interrupted at time t3, and the first switch SW1 is turned on. When the first switch SW1 is turned on, the disconnected portion is bypassed, and the drive current I OUT starts flowing again and the high beam remains on, but the first light source 310 is turned off, so no light is emitted into the low beam area.

[0126] Fig. 22 is a fourth operational waveform diagram of the light source module 300. Fig. 22 shows a state in which a disconnection fault occurs in the third light source 330 while the high beam is on. The operation from times t0 to t2 is the same as that in Fig. 21.

[0127] At time t2, when a disconnection fault occurs in the third light source 330, the driving current I OUT is cut off. If this state continues for a second time T2, at time t3 it is determined that the current is cut off, and the first switch SW1 is turned on. Even when the first switch SW1 is turned on, the broken point is not bypassed, so the current is cut off. Then, at time t4, the first time T1 has elapsed since the first switch SW1 was turned on, the first switch SW1 is turned off.

[0128] Drive current I OUTIf the disconnection state continues, the driver will notice an abnormality in headlamp 2 because visibility will become dark. When the driver switches from high beam to low beam at time t5, the third switch SW3 is turned off and the second switch SW2 is turned on. Then, the disconnected part is no longer used, and the driving current I OUT will start flowing again and headlamp 2 can continue to be used as low beam.

[0129] Next, a modification related to the fourth embodiment will be described.

[0130] (Variation 1) 20 and 22, the driver, noticing that the headlamps 2 are off, manually switches the headlamps 2 from low beam to high beam (or from high beam to low beam) to restore the headlamps 2 to their on state, but this is not the only option. After first switch SW1 is turned on and then off, controller 420 may automatically switch the states of second switch SW2 and third switch SW3 regardless of an external command to turn the headlamps on. This shortens the off period from time t4 to t5 in FIG. 20 or 22.

[0131] Although this control improves safety by shortening the off-light period, there is a possibility that the driver will not notice the break in the LED string 302 and may continue driving without repairing the lamp. In this case, an indicator indicating a failure of the headlamp 2 may be added to the cockpit.

[0132] (Variation 2) While the first switch SW1 is fixed to the on state, the controller 420 may turn on the second switch SW2 and turn off the third switch SW3 regardless of whether a high beam or low beam is turned on.

[0133] According to this modification 2, manual switching between high beam and low beam is disabled, so the driver can be notified of the disconnection fault. In addition, since the low beam is fixed, glare to surrounding traffic participants can be prevented.

[0134] (Variation 3) Contrary to the second modification, the controller 430 may turn on the third switch SW3 and turn off the second switch SW2 while fixing the first switch SW1 in the on state, regardless of the instruction to turn on the high beam or low beam.

[0135] According to this modification 3, manual switching between high beam and low beam is disabled, so the driver can be notified of the disconnection fault. Also, since people generally drive with low beam more often than high beam, only the high beam is enabled and the low beam is disabled, so the driver can easily notice the disconnection fault.

[0136] (Variation 4) Although the above description has been given of a lamp for a motorcycle, the application of the present invention is not limited to this, and it can also be applied to vehicles such as four-wheeled automobiles and trucks.

[0137] The present invention has been described using specific terms based on the embodiments, but the embodiments merely illustrate the principles and applications of the present invention, and many modifications and changes in arrangement are permitted to the embodiments as long as they do not deviate from the concept of the present invention defined in the claims. [Explanation of symbols]

[0138] 2...headlamp, 4...first optical system, 6...second optical system, 8...heat sink, 10...battery, 100...light source module, 110...first light source, 120...second light source, 130...lighting circuit, 132...drive circuit, 134...bypass switch, 200...light source module, 210...first light source, 220...second light source, 230...third light source, 240...lighting circuit, 242...drive circuit, 244...first switch, 246...second switch, 300...light source module, 302...LED string, 310...first light source, 320...second light source, 330...third light source, SW1...first switch, SW2...second switch, SW3...third switch, 400...lighting circuit, 410...drive circuit, 420...controller.

Claims

1. A light source module for a vehicle that can switch between high beam and low beam, a first light source for low beam; a first switch provided in parallel with the first light source; a second light source for low beam and a second switch connected in series with the first light source; a third light source and a third switch for a high beam that are provided in series on a path parallel to the second light source and the second switch; a drive circuit that generates a drive current in response to an instruction to turn on either the high beam or the low beam; A light source module comprising:

2. 2. The light source module according to claim 1, further comprising a controller that, under normal conditions, (i) turns off the first switch, turns on the second switch, and turns off the third switch in response to an instruction to turn on the low beam, and (ii) turns off the first switch, turns off the second switch, and turns on the third switch in response to an instruction to turn on the high beam.

3. The light source module according to claim 2 , wherein the controller turns on the first switch when detecting a current interruption state.

4. The light source module according to claim 3 , wherein the controller turns off the first switch when the current interruption state continues for a predetermined first time period after the first switch is turned on.

5. 5. The light source module according to claim 4, wherein the first time period is between 2 ms and 500 ms.

6. 6. The light source module according to claim 3, wherein the controller determines that the current is cut off when the state in which the drive current is zero continues for a predetermined second time period.

7. 6. The light source module according to claim 3, wherein the controller turns on the second switch regardless of an instruction to turn on the high beam or the low beam while the first switch is fixed in the on state.

8. The light source module according to any one of claims 3 to 5, wherein the controller turns on the third switch while the first switch is fixed in the on state, regardless of an instruction to turn on the high beam or the low beam.

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