JP7365866B2 - light module - Google Patents

Description

The present invention relates to a lamp module used in automobiles and the like.

Vehicle lamps (for example, headlamps) have multiple functions, such as a high beam, a low beam, a clearance lamp (position lamp), and a DRL (Daytime Running Lamp).

FIG. 1 is a block diagram of a lighting system 1R including a conventional vehicle lighting 10R. FIG. 1 shows blocks related to low beams and high beams. The vehicle lamp 10R receives a DC voltage (input voltage V _IN ) from the battery 2 via the switch 4, and uses the input voltage V _IN as a power source to turn on the low beam light source 12L and the high beam light source 12H. Each of the light sources 12H and 12L includes a plurality of light emitting elements (for example, LEDs) provided in series (or in parallel).

The vehicle lamp 10R includes a low beam lighting circuit 14L and a high beam lighting circuit 14H. An H/L switching signal for switching between high beam and low beam is input to the vehicle lamp 10R. When the lighting circuit 14L is supplied with the input voltage _VIN , it supplies the driving current _ILED1 to the light source 12L to turn it on.

The lighting circuit 14H is switched between enable (operation, on) and disable (non-operation, off) according to the H/L switching signal, and in the enabled state, supplies a drive current I to the light source 12H to light _{the LED2} . let

Japanese Patent Application Publication No. 2006-221886

In the conventional vehicle lamp 10R, the high beam and low beam are formed as independent circuits, which has the problem of being large in cost and size.

The present invention has been made in view of such problems, and one exemplary objective of one aspect of the present invention is to provide a lamp module in which a plurality of functions can be switched.

One aspect of the present invention relates to a lamp module in which a first function and a second function can be switched. The lighting module includes a constant current output drive circuit, a first light source including M light emitting elements (M≧1) and a first switch connected in series with the output of the drive circuit, and N light emitting elements connected in series. (N≧1) light emitting elements and a second switch, a second light source provided in parallel with a series connection circuit including some or all of the M light emitting elements and the first switch; A switching signal instructing switching between two functions is received, and while the first function is instructed, the first switch is made conductive and the second switch is cut off; The switching circuit includes a switching circuit that conducts both the first switch and the second switch when switching between the first function and the second function.

Another aspect of the present invention also relates to a lamp module in which a first function and a second function can be switched. The lamp module includes a first light source including M light emitting elements, a second light source including N light emitting elements, and a constant current output drive circuit provided in common for the first light source and the second light source. , receives a switching signal instructing switching between the first function and the second function, and while the first function is instructed, the output current of the drive circuit flows through the first light source, and while the second function is instructed, the output current of the drive circuit flows through the first light source. The output current of the drive circuit is routed so that the output current of the drive circuit flows through the light source and when switching between the first function and the second function, the output current of the drive circuit flows through both the first light source and the second light source. and a switching circuit for switching.

Note that arbitrary combinations of the above-mentioned constituent elements and mutual substitution of constituent elements and expressions of the present invention among methods, devices, systems, etc. are also effective as aspects of the present invention.

According to an aspect of the present invention, a lamp module having multiple functions can be provided.

FIG. 1 is a block diagram of a lighting system including a conventional vehicle lamp. 1 is a block diagram of a lighting system including a lighting module according to Embodiment 1. FIG. 3 is an operation waveform diagram of the lamp module of FIG. 2. FIG. 4(a) is a circuit diagram showing an example of the configuration of the lamp module of FIG. 2, and FIG. 4(b) is a circuit diagram showing an example of the configuration of the edge delay circuit. FIG. 3 is an exploded perspective view of the lamp module. FIGS. 6(a) and 6(b) are circuit diagrams showing a configuration example of a drive circuit. FIG. 3 is a block diagram of a lamp module according to a second embodiment. FIG. 3 is a block diagram of a lamp module according to a third embodiment. 7 is a circuit diagram of a lamp module according to modification example 1. FIG. 7 is a circuit diagram of a lamp module according to modification 2. FIG.

(Summary of embodiment)
One embodiment disclosed in this specification relates to a lamp module in which a first function and a second function can be switched. The lighting module includes a constant current output drive circuit, a first light source including M light emitting elements (M≧1) and a first switch connected in series with the output of the drive circuit, and N light emitting elements connected in series. (N≧1) light emitting elements and a second switch, a second light source provided in parallel with a series connection circuit including some or all of the M light emitting elements and the first switch; A switching signal instructing switching between two functions is received, and while the first function is instructed, the first switch is made conductive and the second switch is cut off; The switching circuit includes a switching circuit that conducts both the first switch and the second switch when switching between the first function and the second function.

By using a common drive circuit for the first light source and the second light source, size and cost can be reduced. Further, when switching between the first function and the second function, it is possible to prevent both the first light source and the second light source from turning off.

The first function is a low beam, the second function is a high beam, M≧2, and the series-connected circuit may include some of the M light emitting elements and the first switch. As a result, even when the high beam is turned on, it is possible to keep some of the remaining M light emitting elements turned on, so that the low beam can be irradiated with lower illuminance than when the low beam is selected.

The M light emitting elements and the N light emitting elements may be cooled by a common heat sink. The drive circuit, the first light source, the second light source, and the switching circuit may be mounted on a common substrate.

The switching signal is a high/low binary signal, and the switching circuit is capable of generating a first control signal given to the first switch and a second control signal given to the second switch based on the switching signal. The circuit may be configured to be able to delay edges corresponding to turn-off of each of the first control signal and the second control signal.

The first function may be a daytime running lamp and the second function may be a clearance lamp.

(Embodiment)
DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on preferred embodiments with reference to the drawings. Identical or equivalent components, members, and processes shown in each drawing are designated by the same reference numerals, and redundant explanations will be omitted as appropriate. Further, the embodiments are illustrative rather than limiting the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

In this specification, "a state in which member A is connected to member B" refers to not only a case where member A and member B are physically directly connected, but also a state in which member A and member B are electrically connected. This also includes cases in which they are indirectly connected via other members that do not substantially affect the connection state or impair the functions and effects achieved by their combination.

Similarly, "a state in which member C is provided between member A and member B" refers to the case where member A and member C or member B and member C are directly connected, This also includes cases in which they are indirectly connected via other members that do not substantially affect the connection state or impair the functions and effects achieved by their combination.

In addition, in this specification, the symbols attached to electrical signals such as voltage signals and current signals, or circuit elements such as resistors and capacitors, refer to the respective voltage values, current values, resistance values, and capacitance values as necessary. shall be expressed.

(Embodiment 1)
FIG. 2 is a block diagram of the lighting system 1 including the lighting module 100A according to the first embodiment. The lamp system 1 includes a battery 2, a switch 4, a vehicle-side ECU (Electronic Control Unit) 6, and a vehicle lamp 10.

The lamp module 100A is responsible for a first function and a second function among the plurality of functions of the vehicle lamp 10, and is switchable between the first function and the second function. In this embodiment, the vehicle lamp 10 is a headlamp, and the first function is a low beam, and the second function is a high beam.

The light module 100A includes a drive circuit 110, a first light source 120, a second light source 130, and a switching circuit 140, which are made into a unit, and the completed product of the light module 100A is assembled into the vehicle light 10. .

The drive circuit 110 includes a constant current output driver. The configuration of the drive circuit 110 is not particularly limited, and may be a constant current output linear regulator, a constant current output switching converter (DC/DC converter), or a constant voltage output switching converter. It may also be a combination of constant current circuits.

The first light source 120 corresponds to the first function (ie, low beam) and includes M light emitting elements 122_1 to 122_M (M≧1) connected in series with the output of the drive circuit 110 and a first switch SW1. . In the example of FIG. 2, M=3. The light emitting element is preferably an LED (light emitting diode), but other semiconductor light emitting elements such as an LD (laser diode) or an organic EL element may also be used.

The second light source 130 corresponds to a second function (ie, high beam) and includes N light emitting elements 132_1 to 132_N connected in series (N≧1) and a second switch SW2. In the example of FIG. 2, N=2. The second light source 130 is provided in parallel with the series connection circuit 124 including some of the M light emitting elements 122_1 to 122_3 of the first light source 120, 122_2 and 122_3, and the first switch SW1.

The switching circuit 140 receives an H/L switching signal instructing switching between a first function (low beam) and a second function (high beam), and receives a control signal CNT1 instructing turning on and off of the first switch SW1 and the second switch SW2. , CNT2 are generated. For example, the H/L switching signal may be supplied from the vehicle-side ECU 6. The switching circuit 140 turns on the first switch SW1 and cuts off the second switch SW2 while low beam is instructed (for example, when the H/L switching signal is low). The switching circuit 140 turns off the first switch SW1 and turns on the second switch SW2 while the high beam is instructed (for example, when the H/L switching signal is high). The switching circuit 140 conducts both the first switch SW1 and the second switch SW2 for a certain period when switching between low beam and high beam.

The above is the basic configuration of the lamp module 100A. Next, its operation will be explained. FIG. 3 is an operational waveform diagram of the lamp module 100A of FIG. 2. Before time _t0 , the H/L switching signal is low (referred to as a low beam period), the first switch SW1 is on, and the second switch SW2 is off. Therefore, the output current I _OUT of the drive circuit 110 flows to the light emitting elements 122_1 to 122_3 of the first light source 120, the low beam is turned on, and the brightness of the high beam is zero.

At time _t0 , when the H/L switching signal transitions to high, the switching circuit 140 turns on the second switch SW2. The switching circuit 140 does not immediately turn off the first switch SW1, but keeps the first switch SW1 on during the transition period τ ₁ from time t ₀ to t ₁ . During this transition period τ ₁ , both the first switch SW1 and the second switch SW2 are on, so that the output current I _OUT of the drive circuit 110 is shunted to the first light source 120 and the second light source 130, and Both light source 120 and second light source 130 are turned on. The length of the transition period τ ₁ may be, for example, about 50 ms to 500 ms.

At time _t1 , the first switch SW1 is turned off, and after time _t1 , the second light source 130 is turned on, resulting in a high beam period. During this high beam period, the output current I _OUT of the drive circuit 110 flows through the light emitting element 122_1, which is a part of the first light source 120, so the brightness of the first light source 120 does not become zero, and the It can be turned on at low brightness (1/3 brightness in this example).

At time _t2 , when the H/L switching signal transitions to low, the switching circuit 140 turns on the first switch SW1. The switching circuit 140 does not immediately turn off the second switch SW2, but keeps the second switch SW2 on during the transition period τ ₂ from time t ₂ to t ₃ . During this transition period τ ₁ , both the first switch SW1 and the second switch SW2 are on, so that the output current I _OUT of the drive circuit 110 is shunted to the first light source 120 and the second light source 130, and Both light source 120 and second light source 130 are turned on. The length of the transition period τ ₂ can be, for example, about 50 ms to 500 ms. The length of the transition period τ ₂ may be equal to or different from the transition period τ ₁ .

At time _t3 , the second switch SW2 is turned off, and after time _t3 , a low beam period begins, in which the first light source 120 is turned on at high brightness and the second light source 130 is turned off.

The above is the operation of the lamp module 100A. Next, we will explain its advantages. According to this lamp module 100A, a lamp having high beam and low beam functions can be modularized. Thereby, the assembly of the vehicle lamp 10 can be simplified compared to the case where the high beam and low beam are separately unitized.

Furthermore, since the two light sources 120 and 130 are driven by the single drive circuit 110, the number of parts and cost can be reduced, and the size of the lamp module 100A can be reduced.

When the high beam and low beam light sources 120 and 130 are built into a single module, it is difficult to keep the low beam fully lit even during the high beam period due to thermal constraints. However, if the first light source 120 and the second light source 130 are turned on exclusively, due to the control delay, both the first light source 120 and the second light source 130 will be turned off when switching between high beam and low beam, which will reduce safety. There is a risk that it will decrease. According to this embodiment, by inserting transition periods τ ₁ and τ ₂ in which the first light source 120 and the second light source 130 are turned on simultaneously between the high beam period and the low beam period, the first light source 120 and the second light source 130 are turned on simultaneously. Simultaneous extinguishing of the light sources 130 can be prevented, and safety can be improved.

Furthermore, by making the drive current I _OUT always flow through some of the light emitting elements 122_1 of the first light source 120 regardless of the high beam period or the low beam period, the low beam light source is operated at low brightness during the high beam period. It can be made to emit light. This makes it possible to overcome thermal constraints while preventing the illuminance of the low beam light distribution area from becoming zero, further improving safety.

Next, it is a circuit diagram showing a specific example of the configuration of the lamp module 100A. FIG. 4(a) is a circuit diagram showing a configuration example of the lamp module 100A of FIG. 2. The first switch SW1 and the second switch SW2 are N-channel MOS transistors, and their ON and OFF states are controlled by control signals CNT1 and CNT2 applied to their gates.

Switching circuit 140 includes several inverters 142-144 and edge delay circuits 146, 148. The H/L switching signal that has passed through the inverters 142 and 143 is input to an edge delay circuit 146. Edge delay circuit 146 receives the output H/L of inverter 143, inverts it, and generates control signal CNT1. Further, the edge delay circuit 148 receives the H/L switching signal (inverted logic) via the inverter 144, inverts it, and generates the control signal CNT2. The edge delay circuits 146 and 148 each delay the edge (negative edge when the switch is an N-channel MOS transistor or an NPN bipolar transistor) corresponding to the turn-off of the output control signals CNT1 and CNT2. If the switch is a P-channel MOS transistor or a PNP bipolar transistor, the positive edge may be delayed. The number of inverter stages may be designed so that the control signals CNT1 and CNT2 take an appropriate logic level with respect to the H/L switching signal.

FIG. 4(b) shows a configuration example of the edge delay circuit 146 (148). Edge delay circuit 146 includes resistors R11 to R13, PNP bipolar transistor Q11, and capacitor C11. The capacitor C11 is connected to the gate of the NMOS transistor, which is the first switch SW1. Resistor R11 is connected in parallel with capacitor C1. The collector of the transistor Q11 is connected to the capacitor C11, and the H/L switching signal is input to the base via the resistor R12. Further, a resistor R13 is provided between the base and emitter of the transistor Q11. When the input IN of the edge delay circuit 146 transitions to low, the capacitor C11 is charged by the collector current of the transistor Q11, and the control signal CNT1 rises rapidly. When the input IN of edge delay circuit 146 transitions to high, the collector current of transistor Q11 is cut off. At this time, the charge in the capacitor C11 is slowly discharged via the resistor R11, and therefore the control signal CNT1 gradually decreases. That is, a delay is selectively applied only to the negative edge of the control signal CNT1.

Those skilled in the art will understand that the configuration of the switching circuit 140 shown in FIGS. 4(a) and 4(b) is merely an example and is not limited thereto.

Next, the structure of the lamp module 100A will be explained. FIG. 5 is an exploded perspective view of the lamp module 100A. The components of the lamp module 100A are mounted on a common board 160. Specifically, in addition to the plurality of light emitting elements 122 and the plurality of light emitting elements 132, the components of the first switch SW1, the second switch SW2, the drive circuit 110, and the switching circuit 140 are mounted on the substrate 160. The reflector 182 receives the light emitted from the light emitting element 122 and forms a low beam light distribution using the reflected light. Similarly, the reflector 184 receives the light emitted from the light emitting element 132 and forms a high beam light distribution using the reflected light. The heat sink 170 contacts the opposite side (back surface) of the substrate 160 to the mounting surface, and radiates heat from the first light source 120 and the second light source 130.

As a modification of FIG. 5, a plurality of heat sinks 170 are provided, and each heat sink 170 is fixed in contact with a position corresponding to the light emitting elements 122 and 132 on the opposite side (back surface) of the mounting surface of the common board 160. You may.

FIGS. 6A and 6B are circuit diagrams showing a configuration example of the drive circuit 110. The drive circuit 110 in FIG. 6A includes a step-down converter 112 and its controller 114. Step-down converter 112 includes a switching transistor M1, a rectifier D1, an inductor L1, a capacitor C1, and a sense resistor Rs. The sense resistor Rs is provided on the path of the drive current I _OUT . The controller 114 controls the switching transistor M1 so that the voltage drop Vs (Vs=I _OUT ×Rs) across the sense resistor Rs approaches a predetermined target voltage V _REF . Thereby, the output I _OUT is stabilized so as to approach I _REF =V _REF /Rs.

A synchronous rectification type using a transistor may be adopted as the rectification element D1. Further, when the number M of light emitting elements 122 connected in series is large, a boost converter can be used.

As shown in FIG. 6(b), the drive circuit 110 may be configured with a linear regulator.

(Embodiment 2)
FIG. 7 is a block diagram of a lamp module 100B according to the second embodiment. Differences from Embodiment 1 will be explained. In FIG. 7, the first light source 120 includes M=2 light emitting elements 122_1 and 122_2. Further, the second light source 130 is connected in parallel with the series connection circuit 124 including all M light emitting elements 122_1 to 122_2 and the first switch SW1. Therefore, in FIG. 2, the first light source 120 can be completely turned off during the period when the second function is selected.

In the lamp module 100B of FIG. 7, as in the first embodiment, the first function may be a low beam, and the second function may be a high beam. Alternatively, the first function may be a daytime running lamp, and the second function may be a clearance lamp.

(Embodiment 3)
FIG. 8 is a block diagram of a lamp module 100C according to the third embodiment. The difference from Embodiment 1 is the numbers M and N of light emitting elements 122 and light emitting elements 132, and in FIG. 8, M=2 and N=1.

The present invention has been described above based on the embodiments. Those skilled in the art will understand that this embodiment is merely an example, and that various modifications can be made to the combinations of these components and processing processes, and that such modifications are also within the scope of the present invention. be. Hereinafter, such modified examples will be explained.

(Modification 1)
FIG. 9 is a circuit diagram of a lamp module 100D according to Modification 1. The drive circuit 110 includes a current sink type constant current driver (linear regulator). This lamp module 100 is understood to be the lamp module 100A of FIG. 2 upside down. The first switch SW1 and the second switch SW2 are P-channel MOS transistors, and are turned on when the control signals CNT1 and CNT2 are low. Therefore, in the switching circuit 140, the edges corresponding to turn-off of the control signals CNT1 and CNT2 are positive edges, and the switching circuit 140 may delay the positive edges of each of the control signals CNT1 and CNT2.

(Modification 2)
FIG. 10 is a circuit diagram of a lamp module 100E according to a second modification. In the lamp module 100E, the drive circuit 110 includes a boost converter 116 and a controller 118. Boost converter 116 includes an inductor L2, a switching transistor M2, a rectifier D2, a capacitor C2, and a sense resistor Rs. The controller 118 controls the switching transistor M2 so that the voltage drop across the sense resistor Rs approaches the target voltage, and stabilizes the output current _IOUT . The first light source 120 and the second light source 130, which are loads, are provided with their cathodes facing the input terminal side and their anodes facing the output terminal side of the drive circuit 110.

(Modification 3)
In the embodiment, the H/L switching signal is a binary signal of high and low, but it is not limited thereto, and may be in another signal format. In this case, the switching circuit 140 may be configured to determine the currently instructed function based on the H/L switching signal and then generate appropriate control signals CNT1 and CNT2.

(Modification 4)
The arrangement of the switches SW1 and SW2 is not limited to that described in the embodiment, and in combination with the control of the switching circuit 140, the output current _IOUT of the drive circuit 110 flows to (i) the first light source 120 side. , (ii) a state in which the light flows toward the second light source 130 side, and (iii) a state in which the light flows into the first light source 120 and the second light source 130 may be arranged so as to be switchable. Therefore, the number of switches is not limited to two, and three or more switches may be used.

From this viewpoint, one aspect of the lamp module according to the present invention can be understood as follows. The lamp module (100) can be switched between a first function and a second function. The first light source (120) includes M light emitting elements, and the second light source (130) includes N light emitting elements. The drive circuit (110) is provided commonly to the first light source (120) and the second light source (130), and has a constant current output. The switching circuit (140) receives a switching signal that instructs switching between the first function and the second function, and (i) outputs the output of the drive circuit (110) to the first light source (120) while the first function is instructed; (ii) The output current of the drive circuit (110) flows to the second light source (130) while the second function is instructed, and when switching between the first function and the second function, the first light source ( The output current path of the drive circuit (110) is switched so that the output current of the drive circuit (110) flows through both the light source (120) and the second light source (130). In this embodiment, a switch for switching the current path may be arranged in parallel with some light emitting elements.

Although the present invention has been described using specific words and phrases based on the embodiments, the embodiments merely illustrate the principles and applications of the present invention, and the embodiments do not include the scope of the claims. Many modifications and changes in arrangement are possible without departing from the spirit of the present invention.

1 Light system 2 Battery 4 Switch 6 Vehicle side ECU
10 Vehicle lamp 100 Light module 110 Drive circuit 112 Step-down converter 114 Controller 116 Step-up converter 118 Controller 120 First light source 122 Light emitting element 124 Series connection circuit SW1 First switch 130 Second light source 132 Light emitting element SW2 Second switch 140 Switching circuit 142 , 143, 144 Inverter 146, 148 Edge delay circuit 160 Board

Claims (5)

A lighting module whose first function and second function can be switched,
A constant current output drive circuit,
a first light source including M (M≧1) light emitting elements and a first switch connected in series with the output of the drive circuit;
A first switch including N light emitting elements (N≧1) connected in series and a second switch, and provided in parallel with a series connection circuit including some or all of the M light emitting elements and the first switch. 2 light sources and
Upon receiving a switching signal instructing switching between the first function and the second function, the first switch is made conductive while the first function is instructed, the second switch is cut off, and the second function is instructed. a switching circuit that shuts off the first switch and conducts the second switch while switching between the first function and the second function, and conducts both the first switch and the second switch when switching between the first function and the second function; ,
Equipped with
A lamp module , wherein the drive circuit, the first light source, the second light source, and the switching circuit are mounted on a common board . The first function is a low beam, and the second function is a high beam,
2. The lamp module according to claim 1, wherein M≧2 and the series connection circuit includes some of the M light emitting elements and the first switch. 3. The lamp module according to claim 1, wherein the M light emitting elements and the N light emitting elements are cooled by a common heat sink. The switching signal is a high/low binary signal,
The switching circuit is capable of generating a first control signal to be applied to the first switch and a second control signal to be applied to the second switch based on the switching signal,
4. The lamp module according to claim 1, wherein the switching circuit is configured to be able to delay edges corresponding to turn-off of each of the first control signal and the second control signal. 5. The lamp module according to claim 1, wherein the first function is a daytime running lamp, and the second function is a clearance lamp.

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