JP2012133938A - Led module and led light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED module which can reduce the heating value while ensuring some degree of illumination upon occurrence of overheating, and can notify overheating.SOLUTION: An LED module 1 operating under constant current control comprises a series LED circuit 10 where a plurality of light-emitting diodes 13 are connected electrically in series, a protection circuit 18 which is in parallel electrically with a specific range of path 11 including some light-emitting diodes 13 out of the series electrical path of the series LED circuit 10, and a temperature-sensitive section 186 arranged so that the heat generated from the light-emitting diodes 13 acts thereon. When the temperature sensed by the temperature-sensitive section 186 exceeds a predetermined threshold temperature, the protection circuit 18 is short-circuited electrically and some light-emitting diodes 13 are unlighted.

Description

  The present invention relates to an LED lamp that employs a light emitting diode as a light source, and an LED module that constitutes a light source module of the LED lamp.

  2. Description of the Related Art Conventionally, there has been known an LED lamp that performs constant current control on an LED module in which a plurality of LEDs (light emitting diodes) are electrically connected in series, and lights each LED. In such an LED lamp, it is necessary to keep the temperature of the LED within an allowable range by efficiently radiating the heat generated by the LED. If an LED that has exceeded a permissible range and is in a high temperature state continues to be lit, there is a risk that the illuminance will decrease or the lifetime will be shortened. In the worst case, the LED may be destroyed.

  In order to realize a high-quality LED lamp, it is necessary to appropriately assemble the selected heat radiating member after careful consideration of design, such as selection of an appropriate heat radiating member. Furthermore, even if it is a high-quality LED lamp, if there is a construction failure such as being attached to an inappropriate lighting fixture with a low heat dissipation effect or being covered with a heat dissipation member such as glass wool, the design heat dissipation There is a risk that overheating will occur without ensuring.

  Therefore, an LED module that informs the occurrence of overheating by turning off the pilot LEDs in response to overheating (see, for example, Patent Document 1), or suppresses or cuts off the supply current to the LEDs in response to overheating. An LED lamp (see, for example, Patent Document 2) incorporating a safety circuit for dimming or turning off has been proposed.

  However, the conventional LED module and LED lamp have the following problems. Even if one pilot LED is turned off as in the LED module, it is only possible to notify the occurrence of overheating, and if it is used continuously, there is a risk of causing fatal damage to the LED itself. In addition, the LED lamp may be completely turned off in response to overheating. For example, when the LED lamp is installed in a bathroom or bathroom with one lamp specification, it may be inconvenient.

JP 2009-71227 A JP 2010-118245 A

  The present invention has been made in view of the above-described conventional problems, and provides an LED module and an LED lamp that can reduce the amount of heat generation while ensuring a certain level of illuminance when overheating occurs, and that can notify overheating. It is something to try.

The LED module of the present invention is an LED module that operates by constant current control,
A series LED circuit in which a plurality of light-emitting diodes are electrically connected in series and a series of electrical paths formed by the series LED circuit are electrically parallel to a specific path range including some light-emitting diodes. A protection circuit, and a temperature sensing part arranged so that heat generated by the light emitting diode acts,
The protection circuit is an LED module having a small electrical resistance value so that the light-emitting diodes are dimmed or extinguished when a sensed temperature of the temperature sensing unit exceeds a predetermined threshold temperature. Item 1).
Moreover, the LED lamp of this invention is an LED lamp provided with said LED module of this invention (Claim 7).

  The LED module of the present invention includes the protection circuit that is electrically parallel to the specific path range that forms a part of the series of electrical paths formed by the series LED circuit. This protection circuit has a small electrical resistance value when the temperature sensed by the temperature sensing unit exceeds the threshold temperature. Under constant current control, the current flowing into the specific path range parallel to the protection circuit is reduced, and the part of the light emitting diodes belonging to the specific path range is dimmed or extinguished.

If some of the light emitting diodes are dimmed, the amount of heat generated by these light emitting diodes can be suppressed, and overheating can be suppressed. Furthermore, it is possible to notify that some of the light emitting diodes are overheated due to a decrease in illuminance of the LED module in response to light reduction or the like.
On the other hand, other light emitting diodes belonging to the series LED circuit are lit as usual by constant current control even when the protection circuit is activated. Therefore, in the LED module, even if the protection circuit is activated in response to overheating, the LED module is not completely turned off, and a certain illuminance can be secured.

  As described above, the LED module of the present invention and the LED lamp of the present invention including the LED module can suppress the amount of heat generated by dimming or extinguishing the part of the light emitting diodes according to overheating, and the overheating can be suppressed. Even if it occurs, it is an excellent part or product that can notify the occurrence of overheating while ensuring a certain level of illuminance without being extinguished.

Explanatory drawing which shows the assembly structure of the LED lamp containing an LED module in Example 1. FIG. FIG. 3 is a circuit diagram illustrating a circuit configuration of an LED module according to the first embodiment. FIG. 3 is a circuit diagram illustrating a circuit configuration of another LED module according to the first embodiment. The circuit diagram which shows the circuit structure of the LED module in Example 2. FIG. FIG. 6 is a circuit diagram showing a circuit configuration of an LED module in Example 3.

Embodiments of the LED module and LED lamp of the present invention will be described.
As the LED lamp in the present invention, there are various modes such as a bulb type lamp and a fluorescent lamp type lamp. Further, it may be a lamp that is turned on by an external power supply, or a lamp that incorporates a power supply circuit.

  The LED module in the present invention may be a module including a plurality of the series LED circuits exhibiting an electrical parallel relationship. In this case, it is not an essential requirement that the specifications of each series LED circuit are the same, but it is more preferable that the specifications are the same. Furthermore, although the specific path range may be provided only for some series LED circuits, it is more preferable to provide the specific path range for all series LED circuits. At this time, it is not essential to make all the specifications of the specific path range the same for all the series LED circuits, but it is more preferable that the specifications are the same.

Further, it is preferable that the protection circuit is electrically short-circuited when the temperature sensed by the temperature sensing unit exceeds the threshold temperature.
In this case, the part of the light emitting diodes is extinguished and the illuminance of the LED module is further reduced, and the effect of notifying overheating is enhanced. Furthermore, since the heat generation amount of the part of the light emitting diodes can be brought close to zero, the effect of suppressing overheating can be enhanced.

Further, the arrangement area of the part of the light emitting diodes and the arrangement area of the other light emitting diodes belonging to the series LED circuit may be separated in places.
In this case, unevenness in brightness occurs on the light emitting surface of the LED lamp employing the LED module. When human visual characteristics are taken into account, a change in brightness in a two-dimensional plane, that is, unevenness in brightness is more easily recognized than a change in brightness over time. Therefore, if the unevenness of brightness is generated according to the operation of the protection circuit with the above configuration, the notification effect that the overheating has occurred can be enhanced.

Further, the light emission color may be different between the light emitting diodes and the other light emitting diodes belonging to the series LED circuit.
As described above, when the light emitting colors of the part of the light emitting diodes and the other light emitting diodes are made different so that a desired light emitting color can be obtained by mixing the light emitting colors of the two light emitting diodes, Accordingly, when the part of the light emitting diodes is dimmed or extinguished, the light emission color of the LED module changes. For example, the emission color of the part of the light emitting diodes may be set to blue or the like, while the LED module as a whole may be set to realize an emission color close to white. In this case, the light emission color of the LED module gradually becomes reddish as the part of the light emitting diodes are turned off or dimmed. In this case, when the light emitting diodes are turned on if they are alternately arranged like a so-called checkered pattern without dividing the arrangement area of the part of the light emitting diodes and the arrangement area of the other light emitting diodes. Color unevenness can be suppressed.

Further, as the protection circuit, there may be a plurality of protection circuits having different specific path ranges that are electrically parallel, and the threshold temperature may be different for each protection circuit.
In this case, one of the protection circuits is activated in a stepwise manner in response to an increase in the temperature detected by the temperature sensing unit, thereby increasing the number of light emitting diodes that are turned off or dimmed in a stepwise manner. Can do. In order to suppress the amount of heat generation, the number of light emitting diodes to be turned off can be reduced as much as possible, and the illuminance of the LED module can be secured as high as possible.

The number of the light emitting diodes is preferably 50% or more of the number of light emitting diodes belonging to the series LED circuit.
In this case, the effect of suppressing the amount of heat generated according to the operation of the protection circuit is enhanced. For example, if 50% of the light emitting diodes are turned off according to the operation of the protection circuit, the amount of heat generated from the LED module can be reduced to about half. On the other hand, in order to ensure the minimum illuminance even when the protection circuit is activated, the number of the light emitting diodes is preferably set to about 80% or less. With this setting, for example, even when some of the light-emitting diodes are turned off in response to the operation of the protection circuit, it is possible to secure a certain level of brightness by securing a light amount of about 20%. . Further, if the number of light-emitting diodes that are turned off in response to the operation of the protection circuit is set to 80% or less, an overcurrent that may be generated due to a delay in constant current control at the moment when the protection circuit is activated, or the like. The peak value of can be suppressed relatively easily. On the other hand, when the number of light-emitting diodes that are turned off approaches 100%, the fluctuation range of the resistance value of the series LED circuit may increase when the protection circuit operates, and the peak value of the overcurrent may become excessive. In order to avoid the destruction of the light emitting diode that may occur according to the operation of the protection circuit, it is necessary to employ a power source capable of high-precision control to suppress the peak value of the overcurrent. In particular, such a power source is expensive.

Embodiments of the LED module and LED lamp of the present invention will be described below with reference to the drawings.
Example 1
This example is an example related to the LED module 1 and the LED lamp 5 including the protection circuit 18. The contents will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the LED lamp 5 of this example is a lamp in which a bottomed cup-shaped illumination lid 56, the LED module 1, and a heat dissipation plate 58 provided with heat dissipation fins 584 are combined. The LED lamp 5 is driven by constant current control (in this example, 0.5 A) by an external constant current power source 100.

  The illumination lid 56 is a translucent part made of a resin material. The light emitting surface 562 that hits the bottom surface of the illumination lid 56 forms an illumination window that transmits the light generated by the LED module 1. The illumination lid 56 can be fixed to the heat sink 58 via an engagement clip (not shown) provided on the outer periphery of the heat sink 58.

  The heat radiating plate 58 is a component made of a metal material having the mounting surface 582 of the LED module 1 on the illumination lid 56 side and having heat radiating fins 584 formed on the back side. The attachment surface 582 can screw the LED module 1. During the lighting of the LED module 1, the generated heat is transmitted toward the heat radiating plate 58 and is radiated from the heat radiating fins 584. The heat radiating plate 58 also serves as a bottom plate for sealing the back surface of the LED lamp 5.

  The LED module 1 is a module in which an electronic component such as a light emitting diode is surface-mounted on a printed wiring board 12. The printed wiring board 12 of this example is a substrate for LED illumination in which a wiring pattern 124 made of copper foil is disposed on the surface of an aluminum plate 123 provided with an insulating layer 122 made of glass epoxy. The printed wiring board 12 is provided with a screw hole (not shown) for screwing to the heat radiating plate 58.

  Electronic components such as a light emitting diode 13 (hereinafter referred to as LED chip 13), a thermal fuse 16, a thyristor 182, a polyswitch 186, and a resistor 184 are mounted on the printed wiring board 12. On the printed wiring board 12, three series LED circuits 10 in which three LED chips 13A to 13C are connected in series are electrically connected in parallel. The three series LED circuits 10 have the same specifications, and LED chips 13A, 13B, and 13C are arranged from the anode side to the cathode side. The thermal fuse 16 and the poly switch 186 are thermally connected to the LED chip 13 and are arranged so that heat generated by the LED chip 13 acts.

  In the LED chip 13 adopted in this example, a phosphor film is formed so as to cover the light emitting surface of the light emitting diode emitting blue light. The phosphor film is a translucent film in which a yellow-green phosphor powder, a red phosphor powder, or the like is dispersed in a translucent resin such as silicone. Part of the blue light emitted from the light emitting surface is absorbed by the phosphor film and converted into yellow-green light or red light. As described above, white light is generated as a mixed color of the yellow-green light and red light generated in the phosphor film and the blue light which is the original emission color, and is emitted from the phosphor film.

  As shown in FIGS. 1 and 2, the printed wiring board 12 is provided with a + terminal 101 and a − (minus) terminal 109 as power supply terminals for supplying power to the three series LED circuits 10. . The + terminal 101 is electrically connected to the anode side of the LED chip 13A of each series LED circuit 10 via a thermal fuse 16 that blows at 110 degrees. The terminal 109 is electrically connected to the cathode side of the LED chip 13 </ b> C of each series LED circuit 10.

  A protection circuit 18 is provided so as to be electrically parallel to the specific path range 11 from the anode of the LED chip 13B to the cathode of the LED chip 13C in the series of electrical paths formed by the series LED circuits 10. ing. The protection circuit 18 is an electric circuit configured by a poly switch 186, a thyristor 182, and a resistor 184. The polyswitch 186, which is a temperature sensing part, is a polymer-based PTC thermistor (PTC: Positive Temperature Coefficient), and is an element whose resistance value suddenly increases when the sensed temperature exceeds a predetermined trip temperature (threshold temperature). is there.

  In the protection circuit 18, when the sensed temperature of the polyswitch 186 is lower than the trip temperature, the gate potential of the thyristor 182 becomes low level, and the anode-cathode is kept open. On the other hand, when the detected temperature of the poly switch 186 becomes the trip temperature or higher, the gate potential of the thyristor 182 shifts to a high level, and the anode-cathode is switched to a closed state (short circuit state). In this example, a polyswitch 186 having a trip temperature of 90 degrees is employed.

  Next, operation | movement of the LED lamp 5 of this example comprised as mentioned above is demonstrated. The LED lamp 5 is lit by constant current control by the external power source 100 connected to the + terminal 101 and the − terminal 109. If a lighting fixture (not shown) in which the LED lamp 5 is incorporated is appropriately constructed, heat generated from each LED chip 13 is quickly transmitted to the heat radiating plate 58 and efficiently radiated from the heat radiating fins 584. In such a proper lighting state, the LED module 1 does not overheat, and the sensed temperature of the polyswitch 186 does not reach the trip temperature. In this case, the normal lighting state is maintained as it is without the protection circuit 18 being operated.

  On the other hand, if the heat radiation is not properly performed for some reason, the LED module 1 is overheated and the sensed temperature of the polyswitch 186 rises. When the sensed temperature reaches 90 ° which is the trip temperature, the thyristor 182 is switched to the closed state, the protection circuit 18 is activated, the power supply to the LED chips 13B and C is stopped, and the light is turned off.

  If the LED chips 13B and C are turned off, the number of LED chips 13 that are turned on becomes 1/3, and the amount of heat generated from the LED module 1 can be reduced to about 1/3. On the other hand, since the LED chip 13A of each series LED circuit 10 is kept in a lit state as it is, it does not become completely dark even if the protection circuit 18 is activated. Furthermore, in the LED module 1 of this example, the arrangement area of the LED chip 13A and the arrangement area of the LED chips 13B and 13C are divided in place (in areas), so that illumination is performed according to the operation of the protection circuit 18. Brightness unevenness occurs on the light emitting surface 562 of the lid 56. According to the LED lamp 5 of this example, in addition to a decrease in illuminance, it can be notified that there has been overheating due to uneven brightness of the light emitting surface.

Thereafter, even if the overheating is eliminated and the sensing temperature of the poly switch 186 falls below the trip temperature, the LED chips 13B and C are kept off as long as the power is not turned off. Once the power is turned off and then turned on again, the operation of the LED module 1 differs depending on the sensed temperature of the polyswitch 186 at that time. If the detected temperature is equal to or higher than the trip temperature, the LED chips 13B and C are turned off again, and if the detected temperature is lower than the trip temperature, all the LED chips 13A to 13C are turned on.
On the other hand, when the LED chips 13B and C are set in the off state as described above, when the overheating further progresses and the temperature continues to rise, the energization is interrupted by the action of the temperature fuse 16, and all The LED chips 13A to 13C are turned off, and safety is ensured.

  As described above, the LED lamp 5 of this example is an excellent product that can suppress overheating while notifying the LED module 1 without being extinguished even when the LED module 1 is overheated, while notifying that effect. Furthermore, in the LED lamp 5 of the present example, since the illuminance can be suppressed by the operation of the protection circuit 18 built in the LED module 1, it is not necessary to cause the power supply side to perform special control such as reducing the supply current. A relatively simple constant current power supply 100 that outputs a constant current can be adopted, which is advantageous in terms of cost and size.

  It is also possible to employ a constant current power supply 100 that can detect a decrease in power consumption of the LED module 1 according to the operation of the protection circuit 18. In this case, an abnormality of the LED lamp 5 can be detected and notified also on the constant current power supply 100 side. Furthermore, if the protection circuit 18 that automatically recovers when the temperature decreases is employed, it is also possible to employ a constant current power supply 100 that can detect a decrease in power consumption and automatically switch to low power operation. . In this case, the LED lamp 5 can be operated at low power after the protection circuit 18 is automatically restored, and overheating can be avoided in advance. If the LED lamp 5 is operated with low power, it is possible to avoid repeated operations such as overheating → protection circuit operation → temperature drop → protection circuit return → overheating → protection circuit operation →.

In addition, although this example is an example which provided the serial LED circuit 10 which consists of LED chip 13A-C in three systems in parallel, it replaces with this and the number of LED chips 13 which comprise the serial LED circuit 10, or series The number of LED circuits 10 in parallel can be changed as appropriate. Furthermore, it is also possible to configure the LED module 1 with only one series of serial LED circuits 10 without paralleling two or more series of LED series circuits 10 in parallel.
As shown in FIG. 3, a protection circuit 18 using a temperature switch 187 such as a bimetal switch that switches to a closed state when the temperature is higher than a predetermined temperature may be employed.

(Example 2)
In this example, two protection circuits having different operating temperatures are provided based on the LED module of the first embodiment. This will be described with reference to FIG.
In the three series LED circuits 10 of the LED module 1 of this example, the first protection circuit 18A is parallel to the first specific path range 11A including the LED chip 13C, and includes the LED chips 13B and C. The second protection circuit 18B is in parallel with the second specific path range 11B.

  The first and second protection circuits 11A and 11B are circuits configured in the same manner as the protection circuit of the first embodiment (reference numeral 18 in FIG. 2). The first and second protection circuits 11A and 11B have different operating temperatures, that is, the trip temperatures of the poly switches 186A and 186B are set differently. The first protection circuit 18A has a trip temperature of 80 degrees, and the second protection circuit 18B has a trip temperature of 90 degrees.

  The operation of the LED lamp 5 including the LED module 1 as described above will be described. About operation | movement in case the heat radiation from LED module 1 is appropriate, it is the same as that of the LED lamp of Example 1. FIG. On the other hand, the operation when heat radiation is not properly performed and the LED module 1 is overheated is slightly different from that of the first embodiment.

  When the LED module 1 is overheated and the detected temperature of the poly switch 186A exceeds 80 degrees, the thyristor 182A is switched to the closed state, and the first protection circuit 18A is activated first. Then, the LED chip 13C in parallel with the protection circuit 18A is turned off first. Since the amount of heat generation is reduced according to the turn-off of the LED chip 13C, there is a possibility that the LED chips 13A and 13B can be kept turned on thereafter.

On the other hand, when the overheating cannot be suppressed only by turning off the LED chip 13C, the temperature of the LED module 1 may further increase. When the detected temperature of the poly switch 186B exceeds 90 degrees, the thyristor 182B is switched to the closed state, the second protection circuit 18B is activated, and the LED chip 13B is turned off in addition to the LED chip 13C. In the operating state of the second protection circuit 18B, as in the case of the first embodiment, the amount of heat generated from the LED module 1 can be suppressed to about 1/3.
Other configurations and operational effects are the same as those in the first embodiment.

(Example 3)
In this example, the configuration of the protection circuit is changed based on the LED module of the second embodiment. This will be described with reference to FIG.
In the LED module 1 of this example, the first protection circuit 18A is parallel to the first specific path range 11A including only the LED chip 13C of each series LED circuit 10, and the second including only the LED chip D13B. The second protection circuit 11B is parallel to the specific path range 11B.

  The first and second protection circuits 18A and 18B are a combination of a light emitting diode 189A and a light emitting diode 189A and a photothyristor 188A and 188B that emit light according to a temperature sensed by a temperature sensing element (temperature sensing unit) such as a thermistor (not shown). It is configured using a coupler. When the temperature sensed by the temperature sensing element exceeds a predetermined threshold temperature, the corresponding light emitting diode 189 emits light and the photothyristor 188 switches to the closed state.

  The first protection circuit 18A and the second protection circuit 18B have different temperature sensing element specifications. The first protection circuit 18A has a threshold temperature of 80 degrees, and the second protection circuit 18B has a threshold temperature of 90 degrees.

The operation of the LED lamp 5 of this example including such an LED module 1 is substantially the same as the operation of the LED lamp of the second embodiment. When the angle exceeds 80 degrees, the LED chip 13C is turned off. When the angle exceeds 90 degrees, the LED chip 13B is turned off in addition to the LED chip 13C.
Other configurations and operational effects are the same as in the second embodiment.

  As described above, specific examples of the present invention have been described in detail as in the first to third embodiments, but these specific examples merely disclose an example of the technology included in the scope of claims. Needless to say, the scope of the claims should not be construed as limited by the configuration, numerical values, or the like of the specific examples. The scope of the claims includes techniques obtained by variously modifying or changing specific examples using known techniques, knowledge of those skilled in the art, and the like.

DESCRIPTION OF SYMBOLS 1 ... LED module, 10 ... Series LED circuit, 11 ... Specific route range, 12 ... Printed wiring board, 13 ... LED chip (light emitting diode), 18 ... Protection circuit, 186 ... Poly switch (temperature sensing part), 187 ... Temperature Switch (temperature sensing part), 5 ... LED lamp, 58 ... heat sink, 584 ... radiation fin, 56 ... illumination lid, 562 ... light emitting surface

Claims (7)

An LED module that operates by constant current control,
A series LED circuit in which a plurality of light emitting diodes are electrically connected in series;
A protective circuit electrically parallel to a specific path range including a part of the light-emitting diodes among the series of electrical paths formed by the series LED circuit;
A temperature sensing part arranged so that the heat generated by the light emitting diode acts,
The protection circuit is an LED module having a small electrical resistance value so that the light-emitting diodes are dimmed or extinguished when a sensed temperature of the temperature sensing unit exceeds a predetermined threshold temperature.   The LED module according to claim 1, wherein the protection circuit is electrically short-circuited when a sensed temperature of the temperature sensing unit exceeds the threshold temperature.   The LED module according to claim 1, wherein an arrangement area of the part of the light emitting diodes and an arrangement area of other light emitting diodes belonging to the series LED circuit are separated.   3. The LED module according to claim 1, wherein the part of the light emitting diodes and the other light emitting diodes belonging to the series LED circuit have different emission colors. As the protection circuit, there are a plurality of protection circuits with different specific path ranges that are electrically parallel,
The LED module according to claim 1, wherein the threshold temperature is different for each protection circuit.   6. The LED module according to claim 1, wherein the number of the light emitting diodes is 50% or more of the number of light emitting diodes belonging to the series LED circuit. An LED lamp using a light emitting diode as a light source,
An LED lamp comprising the LED module according to claim 1.

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