JP2006313676A - Lighting fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting fixture in which deterioration in light-emitting characteristics and heat deterioration have been prevented by suppressing temperature rise of a light-emitting element caused by heat generated by circuit components for making the light-emitting element such as an LED emit light. <P>SOLUTION: In the lighting fixture equipped with the LED 5 as a light source, a circuit board 42 on which the circuit components for making the LED emit light have been mounted, and an electric connector 4 for connecting the circuit board 42 to a power source, the circuit board 42 is mounted in the electric connector 4, and the LED 5 and the circuit board 42 are connected to each other by an electric cord 3. The temperature rise of the LED caused by the heat generated by the circuit components is suppressed by making the LED5 independent from the circuit board 42. Since the circuit board is mounted in the electric connector 4, reliability is improved without exposure of the circuit board to the outside of a lighting fixture housing, and constitution can be simplified without increase in the number of components constituting the lighting fixture. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lamp that uses a light emitting element such as a light emitting diode (hereinafter referred to as LED) as a light source, and more particularly to a lamp that prevents deterioration of the characteristics and thermal deterioration of the light emitting element due to heat.

  In recent vehicle lamps, lamps using light emitting elements such as LEDs as light sources have been proposed. In this type of lamp, an LED and a circuit component are mounted on a circuit board, and the circuit board is installed inside the lamp. Alternatively, as in Patent Document 1, in the case of a compatible lamp that allows an LED to be used as a light source instead of a conventional incandescent bulb, the LED is placed in a socket of the same standard as the incandescent bulb socket. There is a case in which a circuit board is mounted. In any case, since a lamp using an LED as a light source has the LED mounted on the circuit board, it is used to pass heat generated by the circuit components mounted on the same circuit board, particularly when a standard current is passed through the LED. The heat generated by the current limiting resistor is transmitted to the LED through the circuit board or by radiation, and the LED temperature rises, the luminous efficiency is lowered and the luminous brightness is lowered, or the lifetime is shortened due to thermal degradation. Such problems arise.

In order to solve such problems of light emission efficiency and thermal degradation due to heat generation of the LED, in Patent Document 2, a current limiting resistor is inserted in a part of an electric cord that is pulled out of a lamp and connected to a power source. Has been proposed. In Patent Document 2, the heat generated by the current limiting resistor is radiated outside the lamp and hardly transmitted to the LED inside the lamp. .
JP 2004-63084 A JP 2003-115208 A

  However, in the technique of Patent Document 2, a part of the electric cord is divided, a current limiting resistor is connected to the divided part, and an insulating coating structure for covering the current limiting resistor is required. The structure was complicated. In particular, it is necessary to configure the current limiting resistor as a separate component from the circuit board, which increases the number of components constituting the lamp and causes a complicated configuration of the entire lamp. In addition, since the current limiting resistor is exposed to the outside of the lamp, it is necessary to take measures against water and dust, and it is difficult to ensure reliability. Furthermore, it is effective for the heat generated by the current limiting resistor, but it is generated by the LED mounted on the circuit board or by other circuit components such as a backflow prevention diode or a protection circuit diode. The heat is transferred to other LEDs, and it is difficult to obtain the effect of preventing the temperature rise due to the heat.

  An object of the present invention is to provide a lamp in which heat generated by components mounted on a circuit board does not affect a light emitting element such as an LED, and the light emitting characteristics of the light emitting element are prevented from deteriorating due to temperature rise and thermal deterioration is prevented. To do.

  The present invention relates to a lamp having a light emitting element as a light source, a circuit board on which a circuit component for causing the light emitting element to emit light, and an electric connector for connecting the circuit board to a power source, and the circuit board is disposed in the electric connector. The light emitting element and the circuit board are connected with an electric cord. The circuit component includes at least a current limiting resistor for limiting the current flowing to the light emitting element. The light emitting element is mounted on the lamp housing, and the electrical connector is configured separately from the lamp housing.

  In the present invention, it is preferable that the circuit board is built in the connector housing of the electrical connector, and the electrodes provided on the circuit board are configured as connector terminals. In addition, the light emitting element is preferably mounted on a socket that can be attached to and detached from the lamp housing. In this case, it is preferable that the socket includes a metal electrode with good heat dissipation, and the light emitting element is connected to the metal electrode.

  According to the present invention, since the light-emitting element can be configured independently of the circuit board, it is easy to take heat dissipation measures for the light-emitting element, and temperature rise in the light-emitting element can be suppressed. In addition, the circuit board is housed in an electrical connector that is connected to the light emitting element with an electric cord, so that heat generated by the circuit components on the circuit board does not affect the light emitting element and suppresses the temperature rise of the light emitting element. can do. As a result, it is possible to prevent a decrease in light emission efficiency and thermal degradation accompanying a temperature increase of the light emitting element. In addition, since the circuit board is housed in the electrical connector, the circuit components are not exposed to the outside of the lamp housing, which is advantageous for improving reliability, and the number of components constituting the lamp is not increased. Can be simplified.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway perspective view of an embodiment in which the present invention is applied to an automotive lamp, and FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, for example, an example applied to a tail lamp TL of an automobile. The lamp housing 1 includes a lamp body 11 having a shallow container shape, and a lens 12 attached to the front opening of the lamp body 11. Here, the lens 12 is a red lens. Arc surface recesses 13 are formed as reflectors at a plurality of locations on the inner surface of the lamp body 11, and the surface thereof is configured as a light reflecting surface by painting or vapor deposition of aluminum. In addition, socket mounting holes 14 are opened at a plurality of positions on the rear surface of the lamp body corresponding to the reflectors, and LED sockets 2, which will be described in detail later, are detachably attached to the socket mounting holes 14. Yes. As will be described later, the LED socket 2 is mounted with an LED 5 as a light source, and the plurality of LED sockets 2 are here connected in series by an electric cord 3. A plurality of electrical cords 3 connected to each row are bundled together at each end and connected to one electrical connector 4. This electrical connector 4 can be fitted into a power source connector 6 connected to a power source not shown in the drawing, that is, a vehicle-mounted battery, and can be electrically connected to each other.

  3A and 3B are a perspective view and a partially broken side view of the LED socket 2, respectively. The socket housing 21 has a generally cylindrical shape, and a bayonet portion 22 that can be attached to and detached from the socket mounting hole 14 is provided in a part of the length of the socket housing 21. The bayonet portion 22 includes a plurality of bayonet pieces 22a protruding in a radial direction at a plurality of locations in the circumferential direction, and a circular flange 22b provided at a predetermined interval in the cylinder axis direction from the bayonet pieces 22a. Since the configuration is the same as that of a conventionally used incandescent bulb socket, detailed description is omitted, but the LED socket 2 is inserted into the socket mounting hole 14 and the shaft is rotated. It can be fixed to or removed from the lamp body 11 by rotating the direction by a small angle and sandwiching the inner edge of the socket mounting hole 14 between the bayonet piece 22a and the flange 22b. By mounting the LED socket 2 in the socket mounting hole 14 of the lamp housing 11, it is possible to change a lamp using an incandescent bulb as a light source to a lamp using an LED as a light source.

  A pair of electrodes 23 in which metal pieces are processed are supported in the interior of the socket housing 21. These electrodes 23 are fitted into slits 24 formed along the inner side of the socket casing 21, and locking pieces 23 a cut and raised in a part of the electrodes 23 are fitted into holes 21 a provided in the socket casing 21. This prevents the dropout. The tip 23b of each electrode 23 is bent so as to face each other and exposed to the tip opening 21b of the socket housing 21, and the LED 5 is soldered, welded, and caulked to the exposed tip 23b. It is fixed in an electrically connected state by, for example. Alternatively, a one-touch type fitting structure may be used instead of these fixing structures. Here, the LED 5 is formed by bending a pair of lead terminals 52 having an enlarged width so as to serve also as a heat radiating plate on the bottom surface of a rectangular package body 51 in which LED elements not shown in the figure are housed. A discrete LED having a lens 53 for condensing light emitted from the LED element is employed, and the pair of lead terminals 52 are connected to the tip 23b of each electrode 23. . The electric cords 3 are connected to the base end portions 23c of the respective electrodes 23 by caulking, and are drawn out from the base end opening portions 21c of the socket housing 21 to the outside.

  On the other hand, FIG. 4 is a longitudinal sectional view of the electrical connector 4. The electrical connector 4 has a circuit board 42 embedded in a connector housing 41 formed of an insulating material such as resin, and is fixed by screws 43. As will be described later, circuit components for causing the LED 5 to emit light and controlling light emission are mounted on the circuit board 42, and are electrically connected to the end of the electric cord 3. In addition, a connector terminal 44 is integrally supported on a part of the circuit board 42, and a distal end portion of the connector terminal 44 is disposed in a rectangular opening 45 provided in a part of the connector housing 41. When the power supply side connector 6 is fitted into the opening 45, the power supply side connector terminal that does not appear in the figure of the power supply side connector 6 is contacted to be electrically connected. In this embodiment, since the tail lamp TL also functions as a stop lamp, three connector terminals 44 are provided. As will be described later, one is a ground connector terminal and the other is a stop power connector terminal. The remaining one is configured as a tail power connector terminal.

  FIG. 5 is an electric circuit diagram of the electric connector 4 including the LED 5 and the circuit board 42. The LEDs 5 mounted on the LED sockets 2 mounted on the lamp body 11 of the tail lamp TL are connected in series in a predetermined number unit to form a plurality of LED rows. Each LED row is electrically connected to the circuit board 42 of the electrical connector 4 by the electrical cord 3. As the three connector terminals 44, the ground connector terminal GND, the stop power connector terminal ST, and the tail power connector terminal TT are electrically connected to the circuit board 42. A plurality of current limiting resistors R are mounted on the circuit board 42, and each of the current limiting resistors R is connected between the ground connector terminal GND and a plurality of power cords 3, and a plurality of LED examples. Are connected in series. Further, a protection circuit P constituted by a protection diode is connected so as to be connected in parallel with the plurality of LED rows. The power supply side of the protection circuit P is connected to the stop power connector terminal ST via a backflow prevention diode D1, and simultaneously connected to the tail power connector terminal TT via a tail control circuit TC and a backflow prevention diode D2. The current limiting resistor R, the circuit components constituting the protection circuit P, the backflow prevention diodes D1 and D2, and the circuit components constituting the tail control circuit TC are mounted on the circuit board 42, respectively, and the electrical connector 4 It is arranged in the inside.

  In the tail lamp having the above configuration, the LED socket 2 is mounted in the socket mounting hole 14 of the lamp housing 1, and the power connector 6 is connected to the electrical connector 4 connected to the electrical cord 3 drawn from the LED socket 2 of each row. , The circuit board 42 or the LED 5 is connected to a power source, and the LED 5 can emit light. It goes without saying that the light emitted from the emitted LED 5 is reflected forward by the arcuate concave portion 13 as a reflector and is emitted to the outside through the lens 12. When the tail lamp TL is lit, the power controlled by the lighting control circuit provided in the automobile is supplied to the tail power connector terminal TT of the electrical connector 4 via the power connector 6. At this time, a low current is passed through the LEDs 5 under the control of the tail control circuit TC, and each LED 5 emits light with low luminance. When the driver operates the brake, power is supplied to the stop power connector terminal ST of the electrical connector 4 by the lighting control circuit described above. At this time, since the power is not controlled by the tail control circuit TC, a high current is passed through the LEDs 5, and each LED 5 emits light with high brightness. In any case, the current flowing through each LED 5 is controlled to be an appropriate current by the current limiting resistor R connected in series to each column of each LED 5.

  As described above, when the LED 5 of the tail lamp TL emits light, the LED 5 generates heat, and the current limiting resistor R mounted on the circuit board 42, the components constituting the protection circuit P, and the tail control circuit TC are constituted. Since current flows through the components and the backflow prevention diodes D1 and D2, these components also generate heat. At this time, the heat generated in the LED 5 is transmitted to the electrode 23 constituting the LED socket 2 and is dissipated from the electrode 23, so that the temperature rise due to the self-heating of the LED 5 is suppressed. Further, since the plurality of LEDs 5 are individually mounted on the LED socket 2, the heat generated by one LED 5 does not affect the other LEDs 5, and the temperature rise due to mutual heat generation of the LEDs 5 is suppressed.

  On the other hand, the temperature of the circuit board 42 rises due to the heat generated by each circuit component mounted on the circuit board 42, but the circuit board 42 is built in the electrical connector 4 and separated from the LED 5 via the electrical cord 3. Since it is disposed at the position, even if the temperature in the electrical connector 4 rises, the heat is not transmitted to the lamp housing 1 and the LED 5. Further, since the connector terminal 44 is provided on the circuit board 42 and the connector terminal 44 is connected to the power supply side connector 6, the heat generated in the circuit component is dissipated through the connector terminal 44, and the circuit This is advantageous in suppressing the temperature rise of the substrate 42. As a result, it is possible to prevent a decrease in luminous efficiency due to a temperature rise of the LED 5 and a shortening of the service life due to thermal degradation. Further, since the circuit board 42 is built in the electrical connector 4, the circuit components are not exposed to the outside of the lamp housing, which is advantageous in improving the reliability, and it is necessary to take measures against dust and waterproofing of the circuit components. Therefore, the number of parts constituting the lamp does not increase and the configuration can be simplified.

  Further, in this embodiment, the LED socket 2 can be configured by adopting the structure of a conventionally used incandescent bulb socket by changing the configuration of the portion where the LED 5 is mounted slightly. Since the circuit board 42 can be built, the structure of the conventional electrical connector can be adopted as it is, so that the design and manufacture are facilitated. In particular, in the embodiment, the connector terminal 44 erected on the circuit board 42 is configured as a connector terminal for connecting the power source side connector of the electrical connector 4, which is advantageous in simplifying the structure of the electrical connector 4. At the same time, there is an advantage that the lamp housing 1 and the power supply side connector 6 can be used as they are, using a conventional lamp using an incandescent bulb.

  FIG. 6 is a perspective view in which a part of the lamp of the second embodiment is broken, and shows an example applied to the tail lamp TL of an automobile as in the first embodiment. In addition, the same code | symbol is attached | subjected to the part equivalent to Example 1. FIG. The lamp housing 1 is composed of a lamp body 11 and a lens 12 on the front surface thereof, and an LED substrate 7 on which a plurality of LEDs 5 are mounted is housed in the lamp housing 1. In addition, a reflector 8 is disposed on the front side of the LED substrate 7, the LED 5 is exposed in a window 81 opened in the reflector 8, and light emitted from the LED 5 is reflected by the reflector 8 and radiated forward. . Here, the LED 5 is the same as the LED of the first embodiment, and a pair of lead terminals 52 that also serve as a heat radiating plate protrude from the bottom surface of the package body 51 in which an LED element not shown in the figure is housed. A lens 53 that collects light emitted from the LED element is disposed on the top surface.

  The LED substrate 7 is composed of a base 71 made of an insulating material and a plurality of electrode plates 72 fixed to the surface of the base 71 so as to be insulated from each other, as shown partially enlarged in FIG. Is done. The electrode plates 72 are opposed to each other with a minute gap therebetween, and LED fixing portions 73 are formed at portions facing the minute gap. The LED fixing portion 73 is formed by bending and raising four portions of each electrode plate 72 as tongue pieces 74, and bending a part of the tongue piece 74a located on the innermost side in an inverted U shape. It is. In the LED fixing portion 73, the lead terminal 52 of the LED 5 is brought into contact with the electrode plate 72 in a region surrounded by the tongue piece 74, whereby the lead terminal 52 is elastically contacted with the tongue piece 74a. At the same time, the contact between the lead terminal 52 and the tongue piece 74a is electrically connected to each other and is electrically connected to the electrode plate 72. The LED board 7 has an electric cord 3 connected to each electrode plate 72. The electric cord 3 is pulled out from the lamp housing 1, and an electric connector 4 similar to that of the first embodiment is provided at the tip thereof. It is connected.

  The electric circuit of the second embodiment is the same as the circuit of the first embodiment shown in FIG. Also in Example 2, only the LED is mounted on the LED substrate, and all of the circuit components such as the current limiting resistor and the circuit components such as the backflow prevention diode are included in the electrical connector. It is mounted on the circuit board. The configuration of the electrical connector is the same as that of the first embodiment.

  According to the second embodiment, the heat generated in the LED 5 when the LED 5 emits light is transmitted to each electrode plate 72 through the lead terminal 52 and is radiated from the surface of the electrode plate 72 having a large area. Therefore, the heat dissipation effect in the LED 5 is higher than that in the first embodiment, and the temperature increase due to heat generation between adjacent LEDs 5 can be effectively suppressed as well as the temperature increase due to heat generation of the LED 5 itself. Also in the second embodiment, even if the temperature of the circuit board 42 rises due to the heat generated by the circuit components including the current limiting resistor R mounted on the circuit board 42 in the electrical connector 4, the circuit board 42 Since it is built in the electrical connector 4 and is disposed at a position away from the LED 5 via the electrical cord 3, even if the temperature of the electrical connector 4 rises, the heat is not transmitted to the LED 5. . Thereby, like Example 1, the fall of the light emission efficiency accompanying the temperature rise of LED5 and the lifetime shortening by heat deterioration can be prevented. In addition, since the circuit board 42 is housed in the electrical connector 4, the circuit components are not exposed to the outside of the lamp housing 1, which is advantageous in improving reliability, and measures such as dustproofing and waterproofing are unnecessary. Thus, the number of parts constituting the lamp does not increase.

  Here, in the first and second embodiments, the circuit board shows an example in which all circuit components for emitting the LEDs 5 other than the LEDs are mounted. However, the circuit components with little heat generation are less affected by the heat on the LEDs 5. You may arrange | position to the LED socket 2 or the LED board 7. FIG. Further, the circuit configuration is not limited to the circuit shown in FIG. 5, and can be applied to a circuit having a configuration in which an LED group in which a plurality of LEDs are connected in parallel is connected in series with a current limiting resistor.

  In addition, the electrical connector does not necessarily have to be a separate body from the lamp housing, and is formed integrally with the lamp housing, particularly a part of the lamp body, as long as it does not affect the LED at a position away from the LED. Or it is good also as a structure supported integrally.

  The present invention is not limited to the tail lamp of the embodiment, and can be similarly applied to any lamp that uses a light emitting element such as an LED as a light source. The present invention is particularly advantageous when applied to a case where the light source of a lamp using an incandescent bulb as a light source is changed to an LED or the like.

It is the perspective view which fractured | ruptured a part of tail lamp of Example 1 of this invention. It is the sectional view on the AA line of FIG. It is the perspective view and BB sectional drawing of an LED socket. It is a longitudinal cross-sectional view of an electrical connector. It is a circuit diagram of the light emission circuit of LED. 6 is a cross-sectional view of a tail lamp of Example 2. FIG. It is an expansion perspective view of a part of LED board.

Explanation of symbols

1 Lamp housing 2 LED socket 3 Electrical cord 4 Electrical connector 5 LED
6 Power supply side connector 7 LED board 8 Reflector

Claims (6)

  In a lamp comprising a light emitting element as a light source, a circuit board on which a circuit component for causing the light emitting element to emit light, and an electric connector for connecting the circuit board to a power source, the circuit board is disposed in the electric connector. The lamp is characterized in that the light emitting element and the circuit board are connected by an electric cord.   The lamp according to claim 1, wherein the circuit component includes at least a current limiting resistor for limiting a current to be supplied to the light emitting element.   The lamp according to claim 1, wherein the light emitting element is mounted on a lamp housing, and the electrical connector is configured separately from the lamp housing.   The lamp according to any one of claims 1 to 3, wherein the circuit board is built in a connector housing of the electrical connector, and an electrode provided on the circuit board is configured as a connector terminal.   The lamp according to any one of claims 1 to 4, wherein the light emitting element is mounted on a socket that can be attached to and detached from the lamp housing. The lamp according to claim 5, wherein the socket includes a metal electrode with good heat dissipation, and the light emitting element is connected to the metal electrode.

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