Light emitting device using LED
View Patent ↗A light emitting device that can provide enhanced heat radiation as well as allowing light from a light emitting diode (LED) chip to be efficiently extracted out of the device. This light emitting device includes a metal plate ( 11 ) that is made of aluminum. The metal plate ( 11 ) has a projection ( 11 a ) projecting forward. The projection ( 11 a ) has a front side provided with a housing recess ( 11 b ). An LED chip ( 1 ) is mounted on the bottom of the housing recess ( 11 b ) so that it is thermally coupled to the metal plate ( 11 ), thus allowing heat to be radiated efficiently. A printed circuit board ( 12 ), having a grass epoxy substrate to be joined to the front surface of the metal plate ( 11 ), is provided with an insertion hole ( 13 ) into which the projection ( 11 a ) is inserted. The LED chip ( 1 ) and a bonding wire (W) are encapsulated in a transparent resin seal portion ( 50 ). The side wall of the housing recess ( 11 b ) that is part of the metal plate ( 11 ) functions as a reflector for reflecting forward light emitted from the LED chip ( 1 ). Thus, light from the LED chip ( 1 ) can be extracted efficiently.
1. A light emitting device using an LED, comprising:
a metal plate having a frontwardly extending projection, the projection having a front provided with a housing recess;
a light emitting diode chip disposed on a bottom of the housing recess to be thermally coupled to the metal plate;
an insulating substrate having an insertion hole into which the projection extends, the insulating substrate being joined to the metal plate in layers; and
a light-transmitting sealing resin in which the light emitting diode chip is encapsulated.
2. The light emitting device according to claim 1 , wherein the insulating substrate has a resin filled portion in which at least part of the sealing resin extends.
3. The light emitting device according to claim 2 , further comprising a frame member joined to a front surface of the insulating substrate so as to surround the insertion hole, wherein the sealing resin provides a resin filled portion of the frame member.
4. The light emitting device according to claim 3 , wherein the frame member has an inside wall provided with a metallic reflecting film having a reflectance higher than a reflectance of the frame member.
5. The light emitting device according to claim 2 , wherein the insulating substrate is a three-dimensional molded circuit board having a wiring portion extending along a peripheral surface of the resin filled portion for electrical connection to the light emitting diode chip.
6. The light emitting device according to claim 1 , wherein the metal plate comprises part of the wiring portion for electrical connection to the light emitting diode chip.
7. The light emitting device according to claim 1 , wherein the housing recess has an inner surface provided with a metallic reflecting film having a reflectance higher than a reflectance of the metal plate.
8. The light emitting device according to claim 1 , wherein the housing recess has a periphery configured as a segment of a paraboloid of revolution.
9. The light emitting device according to claim 1 , said metal plate having a plurality of projections and at least one groove positioned between at least two of said projections whereby the adjacent projections are electrically isolated from each other.
10. The light emitting device according to claim 1 , said housing recess having a wall extending frontwardly from the metal plate, said wall being spaced from a wall of the insertion hole and light emitting ceiling resin being provided in the space between the housing recess wall and the insertion hole wall.
11. The light emitting device according to claim 1 , further comprising a mounting portion projecting forwardly from a bottom of the housing recess, the light emitting diode chip being mounted on the mounting portion.
12. A light emitting device using an LED, comprising:
a metal plate having a frontwardly extending projection, the projection having a front provided with a housing recess;
a light emitting diode chip disposed on a bottom of the housing recess to be thermally coupled to the metal plate;
an insulating substrate having an insertion hole into which the projection extends, the insulating substrate being joined to the metal plate in layers;
a light-transmitting sealing resin in which the light emitting diode chip is encapsulated, the insulating substrate having a resin filled portion in which at least part of the sealing resin extends,
a frame member joined to a front surface of the insulating substrate so as to surround the insertion hole, the sealing resin providing resin filled portion of the frame member, and
a circuit component mounting substrate joined to a front surface of the insulating substrate adjacent the frame member, the circuit component mounting substrate having a front surface provided with a wiring portion,
wherein the circuit component mounting substrate has a thickness such that the frame member is prevented from protruding forward beyond the circuit component mounting substrate.
13. A light emitting device using an LED, comprising:
a metal plate having a frontwardly extending projection, the projection having a front provided with a housing recess;
a light emitting diode chip disposed on a bottom of the housing recess to be thermally coupled to the metal plate;
an insulating substrate having an insertion hole into which the projection extends, the insulating substrate being joined to the metal plate in layers;
a light-transmitting sealing resin in which the light emitting diode chip is encapsulated, the insulating substrate having a resin filled portion in which at least part of the sealing resin extends,
a frame member joined to a front surface of the insulating substrate so as to surround the insertion hole, the sealing resin providing a resin filled portion of the frame member, and
the insulating substrate having a reflector with a reflectance that is higher than a reflectance of the insulating substrate, on a front surface of the insulating substrate inside the frame member.
14. A light emitting device using an LED, comprising:
a metal plate having a frontwardly extending projection, the projection having a front provided with a housing recess;
a light emitting diode chip disposed on a bottom of the housing recess to be thermally coupled to the metal plate;
an insulating substrate having an insertion hole into which the projection extends, the insulating substrate being joined to the metal plate in layers; and
a light-transmitting sealing resin in which the light emitting diode chip is encapsulated,
wherein the insulating substrate has a predetermined portion at which the metal plate is not provided, the predetermined portion of the insulating substrate having a surface at which circuit components are mounted.