JP2012104747A - Led light-emitting unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED light-emitting unit, having increased heat dissipation efficiency at lighting on by immersing LED elements into a cooling liquid, without causing an increased inner pressure of an enclosed space filled with the cooling liquid if the cooling liquid is thermally expanded by a temperature rise caused by the heat evolution of the LED element.SOLUTION: An LED optical unit 1 is configured to have a cap 3 connected to a mouthpiece 2, and an enclosed space 16 formed by the cap 3, a diaphragm housing cylinder 5 fixedly held by the cap 3 and a diaphragm 15 housed and held inside the diaphragm housing cylinder 5. Further, the enclosed space 16 is filled with a cooling liquid 4, and metal bases 11, 12 having the LED 13, 14 mounted thereon are immersed in the cooling liquid 4.

Description

  The present invention relates to an LED light emitting unit, and more particularly, to an LED light emitting unit having excellent heat dissipation performance with respect to an LED element of a light emitting source.

  Conventionally, as this type of LED light emitting unit, for example, one having the following configuration has been disclosed.

  As shown in FIG. 8, a semiconductor laser chip 82 is formed by a cap 85 having a glass plate 84 attached to an opening 83 and a stem 80 by die bonding a semiconductor laser chip 82 to a copper block 81 provided on the stem 80. 82 and the copper block 81 are formed, and an insulating inert liquid 87 is filled so as to leave the space 86 in the space.

  Thereby, the heat generated by the semiconductor laser chip 82 is not only radiated from the contact surface between the copper block 81 and the semiconductor laser chip 82 but also radiated from the entire surface of the semiconductor laser chip 82 to the insulating inert liquid 87. The

  As a result, the entire semiconductor laser chip 82 is efficiently cooled by the insulating inert liquid 87 and the temperature rise of the semiconductor laser chip 82 is suppressed, so that the output of the semiconductor laser chip 82 is increased and the end face of the semiconductor laser chip 82 is deteriorated. It is that prevention can be realized.

  In this case, the space 86 serves to prevent the package shape from being deformed or damaged when the insulating inert liquid 87 undergoes thermal expansion as the temperature of the semiconductor laser chip 82 increases due to heat generation. have.

  Further, as shown in FIG. 9 with respect to the above-described configuration, an inner cylinder 88 is provided inside the cap 85, and the microcapsule 89 is filled between the cap 85 and the inner cylinder 88, and the cap 85 and the stem 80 are formed. Some of these spaces are completely filled with an insulating inert liquid 87.

  Thus, as in the configuration of FIG. 8, the heat generated by the semiconductor laser chip 82 is not only radiated from the contact surface between the copper block 81 and the semiconductor laser chip 82 but also insulated from the entire surface of the semiconductor laser chip 82. The heat is released to the sex inert liquid 87.

  As a result, the entire semiconductor laser chip 82 is efficiently cooled by the insulating inert liquid 87 and the temperature rise of the semiconductor laser chip 82 is suppressed, so that the output of the semiconductor laser chip 82 is increased and the end face of the semiconductor laser chip 82 is deteriorated. It is that prevention can be realized.

  In this case, the microcapsule 89 is made of, for example, a balloon that is filled with air or an inert gas, a foamable resin having micropores, or the like, and a member that contracts against an external force. When the liquid 87 undergoes thermal expansion as the temperature rises due to heat generated by the semiconductor laser chip 82, the volume of the microcapsule 89 itself is reduced and the package shape is prevented from being deformed or damaged. (For example, refer to Patent Document 1).

Japanese Patent No. 3351103

  Meanwhile, in the semiconductor light emitting device 90 having the configuration shown in FIG. 8, the space 86 contracts due to the thermal expansion of the insulating inert liquid 87, but its internal pressure increases. For example, when the volume ratio of the space 86 and the insulating inert liquid 87 is 1: 9, and the volume of the insulating inert liquid 87 becomes 1.1 times the normal temperature due to the temperature rise, the atmospheric pressure is 1 at normal temperature. The air pressure in the space 86 is increased to 10 atmospheres, and the internal pressure is sufficient to destroy the package.

  On the other hand, in the semiconductor light emitting device 91 having the configuration shown in FIG. 9, the microcapsule 89 contracts due to the thermal expansion of the insulating inert liquid 87, but its internal pressure increases. Therefore, for example, the volume ratio of the total internal volume of each microcapsule 89 to the insulating inert liquid 87 is 1: 9, and the volume of the insulating inert liquid 87 becomes 1.1 times that at normal temperature due to the temperature rise. In this case, the total internal pressure of the microcapsule 89, which was 1 atm at normal temperature, rises to 10 atm, and the internal pressure sufficient to break the package, as in the semiconductor light emitting device 90 having the configuration of FIG. turn into.

  Therefore, the present invention was devised in view of the above problems, and the object of the present invention is to thermally connect the LED element and the LED element to a transparent and insulating coolant filled in the sealed space. The heat dissipating member is immersed in the cooling liquid to increase the heat dissipation efficiency of the LED element. An object of the present invention is to provide an LED light-emitting unit that does not cause damage or damage components.

  In order to solve the above-mentioned problems, the invention described in claim 1 of the present invention is characterized in that a cylindrical cap that has translucency and is closed at one end and the other end is joined to an opening end of the cylindrical cap. In contrast, a cylindrical holding body that fixes and holds one end opening end portion of both end openings and the other end opening portion is located in the cylindrical cap, and a volume variable body that is housed and held inside the holding body. In the sealed space formed by the above, a transparent and insulating cooling liquid is filled and a metal base on which the LED is mounted is immersed in the cooling liquid. When the volume of the cooling liquid increases due to a rise in the temperature of the cooling liquid, the volume of the sealed space increases due to the displacement of the volume variable body in the holding body to prevent an increase in the internal pressure of the sealed space. It is characterized by

  According to a second aspect of the present invention, in the first aspect of the present invention, the variable volume body is a cylindrical diaphragm that is made of an elastic elastic member and has one end opened and the other end closed. It is one of a cylindrical or columnar piston that is slidably fitted, and a bellows-like telescopic cylinder that is slidably fitted along the holding body.

  The LED optical unit of the present invention joins a cap and a base, forms a sealed space by the cap, a holding body fixedly held by the cap, and a volume variable body housed and held inside the holding body. The space was filled with a cooling liquid, and a metal base on which an LED was mounted was immersed in the cooling liquid.

  As a result, even if the volume of the coolant increases due to the rise in temperature of the coolant due to the heat generated when the LEDs are turned on, the volume of the sealed space increases due to the displacement of the variable volume body in the holding body, and the internal pressure of the sealed space increases. Can be prevented.

It is a side view of the LED light emission unit concerning embodiment of this invention. Similarly, it is a top view of the LED light emitting unit according to the embodiment of the present invention. Similarly, it is a fragmentary sectional view of the LED light emission unit concerning the embodiment of the present invention. It is explanatory drawing which shows the drive state of a LED light emission unit. Similarly, it is explanatory drawing which shows the drive state of a LED light emission unit. It is a partial cross section side view of the LED light emission unit concerning other embodiment. Similarly, it is a partial cross section side view of the LED light emission unit concerning other embodiment. It is explanatory drawing of an Example. Similarly, it is explanatory drawing of an Example.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. 1 to 7 (the same parts are denoted by the same reference numerals). The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. Unless stated to the effect, the present invention is not limited to these embodiments.

  1 is a side view of an LED light emitting unit according to the present embodiment, FIG. 2 is a top view, FIG. 3A is a partial cross-sectional top view, FIG. 4B is a partial cross-sectional side view, and FIGS. It is explanatory drawing which shows the drive state of a unit, (a) is a partial cross section top view, (b) is a partial cross section side view.

  In the LED light emitting unit 1, the base 2 and the cap 3 are joined, and the cap 3 is filled with the cooling liquid 4, and the bases 11 and 12 fixed to the cap 3 are held in the cooling liquid 4. Similarly, the diaphragm housing cylinder 5 fixedly held to the cap 3 and the diaphragm 15 housed in the diaphragm housing cylinder 5 are immersed.

  The base 2 has a function of a mounting portion for a lamp when the LED light emitting unit 1 is used as a light source of the lamp, and a function of an external connection electrode that receives power from an external power source. Furthermore, by using the base 2 as an attachment portion to the lamp, the LED light emitting unit 1 can be positioned with respect to the lamp with high accuracy and reproducibility. As a result, the light distribution characteristic (light distribution) of the light emitted from the lamp can be ensured with high accuracy, faithfulness, and good reproducibility based on the optical design.

  The cap 3 is made of a transparent member such as resin or glass, and is formed in a cylindrical shape having one end opened and the other end closed in a hemispherical shape.

  Each of the bases 11 and 12 is made of a flat metal member, and a plurality of (four in the present embodiment) bases 11 extend from the base 2 side to the cap 3 side along the central axis X of the base 2. The whole base 12 is arranged so as to extend, and one base 12 is arranged at a columnar upper end (end on the cap 3 side) so as to be perpendicular to the central axis X.

  Each of the four bases 11 arranged in a columnar shape has an LED (in this embodiment, the light emitting surface facing the side (cap 3 side) on the outer surface (the surface facing the cap 3). Two LEDs) 13 are mounted, and the base 12 disposed at the columnar upper end portion has an upper surface (a surface on the side facing the cap 3) and a light emitting surface directed upward (the cap 3 side). (One LED in this embodiment) 14 is mounted.

  Inside the four bases 11 and one base 12, a cylindrical diaphragm housing cylinder 5 is arranged so as to extend from the base 2 side to the cap 3 side along the central axis X of the base 2. In addition, a cylindrical diaphragm 15 made of a stretchable elastic member such as rubber and having one end opened and the other end closed is disposed inside the diaphragm housing cylinder 5, and the opening end 15a is wound outward. The cap 3 is fitted along the outer peripheral surface 3a of the opening end.

  Thereby, the sealed space 16 is formed by the cap 3, the diaphragm housing cylinder 5, and the diaphragm 15, and the four bases 11 on which the LED 13 mounted and fixed to the cap 3 is mounted in the sealed space 16. And the one base 12 with which LED14 was mounted is located. At the same time, the sealed space 16 is filled with a transparent and insulating coolant 4 such as paraffin oil, and the plurality of bases 11 and 12 are immersed in the coolant 4. Yes.

  Therefore, when a voltage is applied to an LED element (not shown) serving as a light emitting source mounted on each of the LED 13 mounted on each base 11 and the LED 14 mounted on the base 12, light emission by energization of the LED element occurs. At the same time, fever occurs. In that case, the light emitting lifetime of the LED element is shortened and the light emission efficiency is lowered due to the temperature rise due to self-heating of the LED element itself. As a result, reliability is reduced and the amount of irradiation light is reduced.

  On the other hand, in the LED light-emitting unit 1 having the above-described configuration, heat generated when the LED element emits light is conducted to the metal base 11 on which the LED 13 is mounted and the metal base 12 on which the LED 14 is mounted. It is efficiently transmitted from the respective surfaces of the bases 11 and 12 to the coolant 4 in contact with the surfaces. Then, the received coolant 4 is transferred to the cap 3 by natural convection in the sealed space 16, transferred from the outer surface of the cap 3 to the outside air in contact with the surface, moves, and the warm air is diffused into the atmosphere. At the same time, part of the heat transferred to the cap 3 is conducted to the metal base 2 and moves to the side of the lamp to which the LED light emitting unit 1 is attached via the base 2.

  As a result, the heat from the LED element is efficiently dissipated, the temperature rise due to self-heating during light emission of the LED element is suppressed, the shortening of the light emission lifetime and the decrease in light emission efficiency due to the temperature rise are suppressed, and high reliability In addition, an appropriate amount of irradiation light can be secured.

  Thus, the LED light-emitting unit 1 having the above-described configuration has excellent heat dissipation means in the LED light-emitting unit 1 itself. For this reason, when the LED light emitting unit 1 is incorporated in a lamp as a light source, it is not necessary to provide heat radiating means such as a heat sink on the lamp side. Therefore, the LED light emitting unit 1 greatly contributes to the reduction in cost and weight of the lamp by being incorporated in the lamp as a light source.

  By the way, when the coolant 4 receives the heat of the LEDs 13 and 14, the coolant 4 expands due to a temperature rise, and the volume increases. Then, as shown in FIG. 4, the diaphragm 15 is crushed by the increased pressure of the coolant 4 and the inner volume of the diaphragm 15 is reduced, and the cap 3, the diaphragm housing cylinder 5, and the diaphragm are correspondingly reduced. 15 and the volume of the sealed space 16 filled with the coolant 4 is increased.

  When the temperature of the coolant 4 further rises, the thermal expansion increases, and the diaphragm 15 is greatly crushed as shown in FIG. 5, and the volume of the sealed space 16 filled with the coolant 4 is further increased.

  Thus, even if the volume of the coolant 4 increases due to the thermal expansion accompanying the temperature rise of the coolant 4, the inner volume of the diaphragm 15 is reduced by crushing the diaphragm 15 made of the elastic elastic member. As a result, the volume of the entire sealed space 16 filled with the cooling liquid 4 is increased, thereby preventing an increase in the internal pressure of the sealed space 16 due to the cooling liquid 4.

  After that, when the LEDs 13 and 14 are turned off and the temperature of the coolant 4 decreases, the volume of the coolant 4 decreases. Then, the squeezed diaphragm 15 is gradually expanded by a repulsive force that opposes the coolant pressure, and finally returns to its original shape to reduce the volume of the entire sealed space 16. As a result, contrary to when the LEDs 13 and 14 are turned on, a drop in the internal pressure of the sealed space 16 due to the coolant 4 is prevented.

  In other words, the internal pressure of the sealed space 16 filled with the coolant 4 is maintained at substantially the same pressure as the atmospheric pressure, regardless of whether the LEDs 13 and 14 are turned on or off. The component member (in this embodiment, for example, the cap 3 in this embodiment) constituting the sealed space 16 is not deformed or damaged, and a highly reliable LED light emitting unit can be realized. .

  6 (partial sectional side view) and FIG. 7 (partial sectional side view) show an increase in the internal pressure of the sealed space 16 filled with the cooling liquid 4 against the thermal expansion of the cooling liquid 4 when the LEDs 13 and 14 are turned on. Instead of the diaphragm 15 having the function of preventing, the same function is exhibited by another configuration.

  Among them, the LED light emitting unit 1 in FIG. 6 is fixedly held with respect to the cap 3 inside the base surrounded by the four bases 11 and one base 12, and along the central axis X of the base 2. A cylindrical cylinder 20 having openings at both ends extending from the second side to the cap 3 side, and a cylindrical or columnar piston 21 slidably fitted in the cylinder 20 are provided.

  In this case, the sealed space 16 filled with the coolant 4 is formed by the cap 3, the cylinder 20, and the piston 21. For this reason, when the coolant 4 that has received the heat generated when the LEDs 13 and 14 are turned on and has risen in temperature is thermally expanded to increase the volume, the increased volume of the coolant 4 flows into the upper end opening of the cylinder 20 (the opening on the cap 3 side). ) To flow into the cylinder 20 and apply a downward pressure (in the direction of the base 2) to the piston 21 to push and move the piston 21 toward the base 2 side.

  As a result, the increase in the volume of the cooling liquid 4 due to the thermal expansion accompanying the temperature rise of the cooling liquid 4 increases the volume of the cooling liquid 4 in the cylinder 20, thereby increasing the volume of the entire sealed space 16. An increase in the internal pressure of the sealed space 16 due to the coolant 4 is prevented.

  Thereafter, when the LEDs 13 and 14 are turned off and the temperature of the coolant 4 decreases, the volume of the coolant 4 decreases. As a result, the piston 21 in the cylinder 20 moves upward (in the direction of the cap 3), and the volume of the cooling liquid 4 in the cylinder 20 is reduced, thereby reducing the volume of the entire sealed space 16 and thereby the LED 13. Contrary to the lighting of 14, 14, a drop in the internal pressure of the sealed space 16 due to the coolant 4 is prevented.

  In other words, the internal pressure of the sealed space 16 filled with the coolant 4 is maintained at substantially the same pressure as the atmospheric pressure, regardless of whether the LEDs 13 and 14 are turned on or off. The component member (in this embodiment, for example, the cap 3 in this embodiment) constituting the sealed space 16 is not deformed or damaged, and a highly reliable LED light emitting unit can be realized. .

  However, in the above configuration, although not shown, when the volume of the coolant 4 is reduced by turning off the LEDs 13 and 14, the piston 21 is pushed upward from the lower side against the coolant pressure. Therefore, it is necessary to keep the pressing force toward the constant pressure applied to the piston 21 at all times. Specifically, it is conceivable to use an elastic member such as a spring or rubber.

  On the other hand, the LED light emitting unit 1 of FIG. 7 is fixedly held to the cap 3 inside the base surrounded by the four bases 11 and one base 12, and the base along the central axis X of the base 2. A cylindrical guide cylinder 30 having both end openings extending from the second side to the cap 3 side, and a bellows-like expansion / contraction cylinder 31 that can expand and contract along the guide cylinder in the guide cylinder 30 are provided.

  In this case, the sealed space 16 filled with the coolant 4 is formed by the cap 3, the guide cylinder 30, and the telescopic cylinder 31. Therefore, when the coolant 4 that has received the heat generated when the LEDs 13 and 14 are turned on and the temperature rises is thermally expanded to increase the volume, the increased volume of the coolant 4 flows into the upper end opening (on the cap 3 side) of the guide tube 30. From the opening) into the guide tube 30 to apply pressure downward (in the direction of the cap 2) to the telescopic tube 31 (the upper portion 32 of the telescopic tube 31), compress the bellows portion 33, and move the upper portion 32 of the telescopic tube 31 to the base. Press and move to the 2 side.

  Thereafter, when the LEDs 13 and 14 are turned off and the temperature of the coolant 4 decreases, the volume of the coolant 4 decreases. Then, the compressed bellows portion 33 is gradually extended by a repulsive force that opposes the coolant pressure, and finally returns to its original shape, thereby reducing the volume of the entire sealed space 16. As a result, contrary to when the LEDs 13 and 14 are turned on, a drop in the internal pressure of the sealed space 16 due to the coolant 4 is prevented.

  In other words, the internal pressure of the sealed space 16 filled with the coolant 4 is maintained at substantially the same pressure as the atmospheric pressure, regardless of whether the LEDs 13 and 14 are turned on or off. The component member (in this embodiment, for example, the cap 3 in this embodiment) constituting the sealed space 16 is not deformed or damaged, and a highly reliable LED light emitting unit can be realized. .

DESCRIPTION OF SYMBOLS 1 ... LED light emission unit 2 ... Base 3 ... Cap 3a ... Outer peripheral surface 4 ... Coolant 5 ... Diaphragm storage cylinder 11 ... Base 12 ... Base 13 ... LED
14 ... LED
15 ... Diaphragm 15a ... Open end 16 ... Sealed space 20 ... Cylinder 21 ... Piston 30 ... Guide cylinder 31 ... Telescopic cylinder 32 ... Upper part 33 ... Bellows part

Claims (2)

A cylindrical cap that has translucency and is closed at one end and the other end is joined to a base,
A cylindrical holding body that fixes and holds one end opening end of both end openings with respect to the opening end of the cylindrical cap, and the other end opening is located in the cylindrical cap;
In a sealed space formed by the volume variable body accommodated and held inside the holding body,
A metal base on which LEDs are mounted is immersed in the cooling liquid while being filled with a transparent and insulating cooling liquid,
When the volume of the coolant increases due to the temperature rise of the coolant due to heat generated when the LED is turned on, the volume of the sealed space increases due to the displacement of the volume variable body in the holding body, and the volume of the sealed space increases. An LED light-emitting unit characterized in that an increase in internal pressure is prevented.   The variable volume body is made of a stretchable elastic member, and has a cylindrical diaphragm with one end opened and the other end closed, a cylindrical or columnar piston slidably fitted in the holding body, and the holding body. The LED light-emitting unit according to claim 1, wherein the LED light-emitting unit is any one of bellows-like telescopic cylinders that are stretchably fitted along.

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