JP2001036148A - Light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently dissipate heat released from a light emitting element outside so as to enhance the element in luminous efficacy and to protect the light emitting element against damages caused by thermal stress in an illuminating light source device, where a solid-state light emitting element is used. SOLUTION: A light emitting element 1 is dipped into a liquid 4 which is insulating, inactive and light transmitting. The liquid 4 or matter dispersed into the liquid 4 may have one of such properties as wavelength conversion, afterglow, and light scattering. Dye which transmits only light of wavelengths close to those of emission light of the light emitting element 1 can be made to serve as the liquid 4 or matter diffused into the liquid 4. The specific gravity of the matter diffused into the liquid is set sufficiently different from that of the liquid or the matter diffused into the liquid is liquid and set equal to the former liquid at a specific gravity at a normal temperature but has no affinity for the former liquid, or a mixture of the liquid 4 and powder can be used, and they are set different from each other in optical properties. Moreover, it is preferable that a part where the heated liquid 4 passes and another part where the cooled liquid 4 passes are isolated from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination light source device using a solid state light emitting device.

[0002]

2. Description of the Related Art An ordinary light emitting diode (LED) is mounted on a metal lead frame, and has a structure in which it is embedded with epoxy resin. LEDs for surface mounting are also mounted on a ceramic or epoxy-based wiring board and covered with epoxy or resin for injection molding.

On the other hand, as an example of an LED having improved heat radiation,
Increasing the lead frame on which the LED is mounted or increasing the number of lead wires to increase the efficiency of thermal connection to the outside, or using a metal-based base instead of the lead frame .

[0004] Further, as an example aimed at reducing thermal stress,
As disclosed in U.S. Pat. No. 5,514,627, there is a structure in which a light emitting element is covered with a gel-like transparent substance, and the periphery thereof is covered with a hard resin.

[0005]

In the structure of an ordinary LED, the thermal resistance from the light emitting element to the lead wire is about 250 ° C./W. Therefore, when a load of 80 mW is applied to the LED, the junction temperature rises by about 20 ° C. with respect to the lead wire. When an LED is used as a lighting device, in normal natural convection, the temperature near the lamp is 20 ° C. lower than room temperature.
The degree rises. Therefore, the junction temperature is
Reaches 60-70 ° C. As a result, the luminous efficiency of the LED decreases by 20 to 30%.

[0006] As described above, this situation is caused by increasing the lead frame on which the LED is mounted or increasing the number of lead wires to increase the efficiency of thermal connection to the outside, or replace the lead frame. In some cases, such as those using a metal-based base, there is a slight improvement. That is, the thermal resistance is about 125 ° C./W.

[0007] The problem of heat dissipation of the LED is that even in the LED having such improved heat dissipation characteristics, heat is dissipated only from the bottom surface of the LED. LED is other LS
Unlike elements such as I, it is not possible to cover the whole with an opaque material because of the need to emit light to the outside. Therefore, other than the bottom surface, it is covered with a transparent resin having poor heat conductivity.

When a large amount of light is passed through one LED to obtain a large luminous flux with a small number of light emitting elements, it is important to dissipate the heat generated from the light emitting elements. This is because, when the temperature of the PN junction rises, the efficiency of the LED is greatly reduced, and the life of the LED is shortened.

Further, a very bright L having a longer wavelength than yellow-green
EDs are made using a GaAs substrate, which is very fragile and vulnerable to external stress. Heat generation expands both the light emitting element and its surrounding materials, but if the coefficients of thermal expansion are different, a large stress occurs between solids. If the LED is blinked and there is a repetitive compression / pulling cycle, the light emitting element suffers great damage.

An object of the present invention is to provide a light source device capable of efficiently radiating heat of a light emitting element to the outside to enhance luminous efficiency and prevent the light emitting element from being damaged by thermal stress. is there.

[0011]

In order to solve the above-mentioned problems, the light source device of the present invention has a structure in which a light-emitting element is immersed in an insulating, inert, and translucent liquid. I do. When the light emitting device is molded in a solid as in the prior art, the light emitting device is very small and has a small surface area, so that there is a limit in releasing heat by heat conduction. However, when immersed in a fluid having fluidity, heat can be transported from the light emitting element by convection, so that the amount of transported heat increases. Conventionally, heat is transferred only from the light emitting element to the lead frame. However, in the present invention, heat can be radiated from the light emitting element in all directions. As a result, all six surfaces of the light emitting element contribute to heat dissipation, and the heat dissipation effect is improved by a factor of six or more.

Further, since the liquid is filled around the light emitting element, the heat of the liquid is radiated out of the module by flowing the liquid into each part of the light emitting module or extracting the liquid to the outside. Is also easy.

Further, since the light emitting element is immersed, it is necessary that the liquid to be used is insulative. However, it is possible to sufficiently exchange heat between the module housing and the light emitting element and to have sufficient insulation. It became possible to keep.

Further, conventionally, the mold resin is deteriorated by a photochemical reaction caused by light from the light emitting element. However, such a problem can be solved. Certainly, the liquid may be degraded by long-time light irradiation.However, since the liquid flows, as in the case of a resin mold, the reaction proceeds in the vicinity of the light emitting element and coloring occurs, which causes the light to flow. It promotes absorption and does not degrade at an accelerated rate. If the total amount of liquid is large, the degradation is averaged out in a large volume and is of little consequence.

Further, since the liquid is filled around the light emitting element, no stress is exerted on the light emitting element due to thermal expansion or the like as long as a small space is provided. Needless to say, it is not promoted. Further, in a liquid, various substances can be mixed, dissolved, and dispersed. By these actions, various applications are possible.

The basic structure of the light emitting module according to the present invention includes a structure in which a substrate on which a light emitting element is mounted is immersed in a box filled with liquid, and the opening of the box is covered with a lens plate. Cover one side of the frame with the board on which the elements are mounted,
There are two types: a structure in which the other surface of the frame is covered with a lens plate. Further, as the simplest configuration using neither a frame nor a box, there is a structure in which a lens plate is directly covered on a surface of a substrate on which a light emitting element is mounted.

[0017]

(Embodiment 1) FIG. 1 shows Embodiment 1 of the present invention. A solid-state light emitting element 1 such as an LED is mounted on a metal-based wiring board 2, and a perforated frame 3 is mounted on the board 2.
After the liquid 4 is filled, a lens plate 6 having a lens 5 formed of a transparent resin is fixed. The liquid 4 used at this time is a colorless inert liquid, and a fluorine-based inert liquid can be used for this. By natural convection of liquid,
Heat transport from the light emitting element 1 and the substrate 2 is promoted, and furthermore, deterioration of the light emitting element 1 due to thermal stress and deterioration coloring of the encapsulating material are almost eliminated.

(Embodiment 2) FIG. 2 shows Embodiment 2 of the present invention. The present embodiment is characterized in that the liquid 4 can move back and forth over a plurality of LED mounting portions in the structure of the first embodiment. As a specific means, spacers are provided around the light emitting module and on the frame 3 so that the lens plate 6 is slightly lifted from the frame 3 for mounting. As a result, the liquid 4 circulates throughout the light emitting module. The light-emitting module usually has a higher temperature in the central part than in the peripheral part. However, if the liquid can be circulated over a plurality of LED mounting parts in this way,
The temperature will be close to uniform and the thermal effect on the LEDs will be uniform. As a result, differences in brightness and durability between the central portion and the peripheral portion are reduced.

(Embodiment 3) FIG. 3 shows Embodiment 3 of the present invention. In the structure of the second embodiment, light leaks in the lateral direction. Therefore, a groove 7 is provided in the lower or upper portion of the frame 3 so as to connect the holes of the portion where the light emitting element 1 is mounted. When assembled, as a result, the gap at the portion where the light emitting element 1 is mounted is connected in a tunnel shape. The liquid 4 circulates through this portion to transport heat by the same principle as that of the second embodiment, so that the temperature can be made uniform. A similar effect can be obtained by providing a gap between the frame 3 and the substrate 2 and providing spacers in some places.

(Embodiment 4) FIG. 4 shows Embodiment 4 of the present invention. Also in the third embodiment, if the groove 7 is enlarged to increase the amount of liquid circulation, light leaks. Therefore, in this embodiment, the fact that light emission from the light emitting element 1 is deviated upward in the light emitting element 1 is used. A step 8 is provided on the surface of the substrate 2 to be mounted by plating or etching, and the light emitting element 1 is mounted thereon. Accordingly, it is possible to reduce light leakage to the groove 7 for circulating the liquid 4.

(Embodiment 5) FIG. 5 shows a characteristic diagram of a wavelength conversion substance used in Embodiment 5 of the present invention. In the figure, B is blue LE
D is the emission color, Y is the emission color of the phosphor as the wavelength conversion material, and C is the emission color spectrum of the incandescent lamp shown for comparison. In this embodiment, in the structure of the first to fourth embodiments, a substance capable of wavelength conversion is dispersed in a liquid. For example, (Ya, Gd _1-a ) ₃ (Al _b , Ga
_{1-b) 5} O _12: using phosphors such as C ₅ ^3+. A light-emitting element that emits blue light is used. Since the above-mentioned phosphor absorbs blue light and emits yellow light, both lights are mixed to generate white light. When the amount of dispersion of the phosphor is changed, the ratio of blue to yellow changes, so that the emission color can be changed.

(Embodiment 6) FIG. 6 is a chromaticity diagram showing a designable range of a luminescent color according to Embodiment 6 of the present invention. In the figure, F
Indicates the emission color range of the phosphor, B indicates the emission color of the blue LED, and T indicates the color temperature of the emission color. In this embodiment, it is possible to express the color inside the sector indicated by the dashed line by changing the kind and the amount of dispersion of the phosphor in the above-described embodiment 5, and to cover a wide range of colors in the chromaticity diagram. Can be issued. This makes it possible to obtain a light source for illumination that is rich in decorativeness.

(Embodiment 7) FIG. 7 shows Embodiment 7 of the present invention. A light emitting element 1 is mounted on a substrate 2, and a housing of the light emitting module is made of a light-transmitting substance so that light can be extracted. Inert inside the light emitting module,
An afterglow substance is dispersed in a translucent liquid 4. As the afterglow substance, for example, Sr ₄ Al ₁₄ O ₂₅ : EuDy is used. The afterglow time of this material was 10 m as shown in FIG.
s or more, but may be longer than the convection and diffusion time of the liquid. Since the afterglow substance absorbs light near the light emitting element 1, diffuses to a place away from the light emitting element 1, and re-emits the light, the in-plane luminance difference of the light emitting surface is reduced. Further, since the afterglow substance as exemplified here is a powder, it diffuses light and further reduces the in-plane luminance difference of the light emitting surface. The combination of the substrate, the light emitting element, the frame, and the lens used here may use any of the structures described in the embodiments of the present invention.

(Eighth Embodiment) FIG. 9 shows an eighth embodiment of the present invention. In the seventh embodiment, the liquid-containing portion has a cylindrical shape, and the light-emitting element 1 is mounted on the bottom thereof. The cylindrical portion 9 may have a thin box shape as shown in FIG. 10 or an elongated cylindrical shape as shown in FIG. Stability can be increased by storing heavy components such as a power supply device in the base 10 supporting the cylindrical portion 9. When the light emitting element 1 emits light, it excites the afterglow substance and heats the liquid. heating·
The excited liquid rises and cools down simultaneously with the de-excitation and falls. Since such circulation occurs, the entire tube appears to emit light. This embodiment can be used for sign and stand lighting.

(Embodiment 9) The above-described embodiment 7 or 8
In the above, the substance dispersed in the liquid may simply scatter light. For example, silica fine particles and the like may be dispersed. When the emission color of the LED is a single color, the rate of forward scattering varies depending on the size of the fine particles, so that it is possible to control the light distribution.
For the combination of the substrate, the light emitting element, the frame, and the lens used in this embodiment, any of the structures described in the embodiments of the present invention may be used.

(Embodiment 10) FIG. 12 shows Embodiment 1 of the present invention.
Indicates 0. In this embodiment, a substance that absorbs a wavelength other than the emission color of the light emitting element 1 is dispersed in the liquid 4. Suppose liquid 4
Is colorless and transparent, when the light emitting element 1 is turned off, external light is reflected by the reflection surface 11 around the light emitting element 1, and the light source surface looks bright. When this LED lighting device is used for a signal light, an indicator light, or the like, it may appear that the LED lighting device emits light when external light is strong. Conventionally, when the LED is molded using resin, by coloring the resin,
Such a phenomenon has been avoided. In a display device or the like, this is a means that has been used to increase the contrast.

Therefore, in this embodiment, in the structure of the above-described embodiments, when the luminescent color is a single color or a mixture of two to four colors, a substance that transmits only this luminescent color, that is, a dye, is mixed into the liquid. . Thereby, the same effect as in the case of the resin coloring described above can be expected. When the resin is colored, fading occurs due to external light, particularly ultraviolet rays. However, in the case of a liquid, if a sufficient amount of the liquid is circulated, the effect of the fading is almost eliminated. This is the same principle as preventing deterioration due to photochemical reaction caused by light from the light emitting element.

(Embodiment 11) FIGS. 13 and 14 show Embodiment 11 of the present invention. In this embodiment, a liquid in which light scattering powder is dispersed is used. In the drawing, black circles drawn in the liquid 4 indicate light scattering powder. Here, the specific gravity of the powder is sufficiently larger than the specific gravity of the liquid 4. Further, the light emitting element 1 is arranged at the focal position of the lens 5 using the lens 5. Reference numeral 12 denotes an apparatus main body, and 13 denotes a power supply and the like. Consider a lantern having such a structure. When this lantern is gently placed, as shown in FIG. 13, light scattering powder precipitates, the liquid 4 becomes transparent, and light from the light emitting element 1 is collected by the lens 5. On the other hand, when vibration is applied, as shown in FIG. 14, the powder is diffused into the liquid 4, so that the light from the light emitting element 1 is scattered, and the light condensing action of the lens 5 does not function sufficiently, and Is obtained. The same effect can be obtained even if the specific gravity of the powder used here is smaller than that of the liquid.

(Embodiment 12) In this embodiment, a liquid in which a powder having wavelength conversion properties is dispersed is used instead of the light scattering powder in the embodiment 11 shown in FIGS. In the figure, black circles drawn in the liquid 4 indicate powder having wavelength conversion properties. Here, the specific gravity of the powder is sufficiently larger than the specific gravity of the liquid. Further, using the lens 5,
The light emitting element 1 is arranged at the focal position of the lens 5. Consider a lantern having such a structure. When this lantern is left gently, as shown in FIG. 13, the powder of wavelength conversion precipitates, the liquid 4 becomes transparent, and the light emitting element 1
The emission color itself from is obtained. On the other hand, when vibration is applied, as shown in FIG. 14, the powder is diffused into the liquid 4, so that a part of the light from the light emitting element 1 is wavelength-converted, and light mixed with the original light is obtained. . The same effect can be obtained even if the specific gravity of the powder used here is smaller than that of the liquid.

(Thirteenth Embodiment) FIGS. 15 and 16 show a thirteenth embodiment of the present invention. In the present embodiment, the eleventh embodiment will be described.
Is characterized in that the specific gravity of the powder and the liquid are sufficiently different from each other, and a portion 14 for storing extra powder is provided. Here, the specific gravity of the powder is sufficiently larger than the specific gravity of the liquid. As shown in FIG. 15, when the apparatus main body 12 is placed vertically, excess powder precipitates, and light from the light emitting element 1 is not scattered.
Beam light is obtained. On the other hand, as shown in FIG. 16, when the apparatus main body 12 is placed horizontally, the powder gathers around the light emitting element 1 and the light from the light emitting element 1 is scattered. Does not work and diffused light is obtained. Thereby, it is possible to select the scattered light or the condensed light depending on the direction in which the light source device is placed. The same effect can be obtained even if the specific gravity of the powder used here is lighter than the liquid.

These embodiments are realized, for example, as plug-in type and rechargeable emergency lanterns as shown in FIGS. 13 to 16, reference numeral 13 denotes a power supply unit including a charging circuit and the like, which also serves as a storage unit for the blade 15 shown in FIG. Further, in the case of the embodiment in which vibration is applied, a small vibrator may be housed.

(Example 14) In Example 12, if the specific gravity of the powder having wavelength conversion property and that of the liquid are sufficiently different and a portion for storing the extra powder is provided, depending on the direction in which the light source is placed, Since the presence or absence of the wavelength conversion function can be selected, the light color can be selected. FIG. 15 and FIG. 16 are explanatory diagrams of the operation when the specific gravity of the powder is heavier than the specific gravity of the liquid.
The same effect can be obtained even if the specific gravity of the powder used here is lighter than the liquid.

(Example 15) In Examples 11 and 12, a plurality of substances having different specific gravities are dispersed in a liquid. For example, one powder having a wavelength conversion function and a larger specific gravity than a liquid is used as one powder, and another powder having a light scattering function and a smaller specific gravity than a liquid is used as another powder. When the light emitting element is a blue LED and the powder having the wavelength conversion function is the phosphor described in Example 5, white light is scattered during the vibration, and when the vibration is stopped, blue light is scattered due to the precipitation of the phosphor. When the light-scattering powder rises, the liquid becomes transparent and changes to blue light collection.

(Embodiment 16) FIGS. 19 and 20 show Embodiment 16 of the present invention. FIG. 19 shows a state at normal temperature, and FIG. 20 shows a state at high temperature. In the figure, black circles drawn in the liquid 4 indicate powder having wavelength conversion properties or light diffusion properties. Since the specific gravity of the liquid 4 changes depending on the temperature, the above-mentioned wavelength converting powder or the like can be obtained by using a change in ambient temperature, a change in the temperature of the light emitting element 1, or a mechanism (a heater or a cooling device) that positively changes the temperature. Light color and light distribution can be changed by dispersing or precipitating light diffusing powder in a liquid.

For example, if the phosphor capable of converting the wavelength from blue to yellow used in Example 5 is dispersed in a liquid, if the ambient temperature increases, the temperature of the liquid also increases, and the specific gravity of the liquid decreases. Therefore, the specific gravity of the phosphor becomes relatively large,
It tends to settle. As a result, light emission of a cooler bluish color than when the ambient temperature is low is obtained. Conversely, when the ambient temperature is low, the yellow light increases and the color becomes warm.
As a result, a lighting device whose light color changes automatically depending on the ambient temperature is obtained.

(Embodiment 17) FIGS. 21 and 22 show Embodiment 17 of the present invention. In the figure, 16 is a transparent cover, 17
Is a portion having water repellency, and 18 is a bottom plate. Cover 16
The liquid 4 is filled in the space between the bottom plate 18. Further, a plurality of light emitting elements 1 are provided on the inner surface of the substrate 2 which also serves as a side plate.
Has been implemented. In this embodiment, as the light emitting element 1,
A green LED is used, and a liquid in which a fluorescent substance that converts green to white is dispersed is mixed with a transparent liquid. If the portion 17 of the transparent cover 16 is made water-repellent to a liquid in which a fluorescent substance that converts green to white is dispersed, this plate naturally emits light separately from white and green. As a result, a sign or the like that emits green light on a white background or white light on a green background can be realized. The use of filters of each color can enhance the color separation effect.

(Eighteenth Embodiment) FIGS. 23 to 25 show an eighteenth embodiment of the present invention. 23 is a front view when the lens plate is removed and the substrate is viewed, FIG. 24 is a cross-sectional view taken along the line AA ′ with the lens plate attached, and FIG. It is sectional drawing about the -B 'line.
In the present embodiment, a partition plate 19 is provided between the lens plate 6 and the substrate 2 in the structure of the second embodiment. The partition plate 19 includes a portion including the light emitting element 1 therebetween and a portion not including the light emitting element 1 therebetween. The light source device of the present embodiment is used for a vertically installed device such as a bracket. The warm liquid 4 that has absorbed heat from the light emitting element 1 rises in a part partitioned by the partition plate 19 containing the light emitting element 1, and the liquid 4 that has radiated heat falls in other parts. As a result, a smooth flow of the liquid 4 occurs, and the cooling effect increases.

(Embodiment 19) FIG. 26 shows Embodiment 1 of the present invention.
9 is shown. In this embodiment, the substrate 2 on which the light emitting element 1 is mounted
In the middle of the housing 20 so that the warm liquid 4 passes through the front and the cooled liquid 4 passes through the back. As a result, a smooth flow of the liquid 4 occurs, and the cooling effect increases. This light source is also used for a vertically installed light source such as a bracket.

(Embodiment 20) FIG. 27 shows Embodiment 2 of the present invention.
Indicates 0. In the present embodiment, a case will be described in which the structure of the above-described embodiment 19 is used as a base-up, that is, an apparatus that is attached to a ceiling surface or the like and illuminates the lower side.
As shown in the figure, a through hole 2 is formed in a substrate 2 on which a light emitting element 1 is mounted, in the vicinity of a position where the light emitting element 1 is mounted.
1 is provided. Thereby, as shown by the arrow, the liquid 4 heated by the light emitting element 1 easily circulates around the back side of the substrate 2 and circulates, thereby enabling waste heat.

Embodiment 21 FIG. 28 shows Embodiment 2 of the present invention.
1 is shown. In the present embodiment, a radiating fin 22 is provided on the back surface of the housing 20 in order to further improve the efficiency of waste heat from the liquid 4 circulating on the back surface of the substrate 2 in the above-described embodiment 19 or 20.

(Embodiment 22) FIG. 29 shows Embodiment 2 of the present invention.
2 is shown. The present embodiment is characterized in that a Peltier element 23 is provided in the housing 20 in order to further improve the efficiency of waste heat from the liquid 4 circulating on the back surface of the substrate 2 in the above-described Embodiment 19 or 20. A heat absorbing portion of the Peltier element 23 is provided on the back surface of the device, and the heat is removed by directing the heat generating portion of the Peltier element 23 to the outside. Further, in order to increase the efficiency of the Peltier element 23, it is conceivable to further attach a radiation fin to the heat generating portion of the Peltier element 23.

Embodiment 23 FIG. 30 shows Embodiment 2 of the present invention.
3 is shown. In this embodiment, in the above-described embodiment 19 or 20, as means for cooling the liquid 4 in order to further improve the waste heat efficiency from the liquid 4 circulating on the back surface of the substrate 2,
A heat exchanger 24 is provided. A refrigerant is introduced from the outside, and a heat absorbing portion is provided in the liquid of the light source device to perform heat exchange. This embodiment is suitable for a case where a large number of LED lighting fixtures are used side by side and where the fixtures are embedded. In addition, as a similar means, use of a heat pipe may be considered.

(Embodiment 24) FIG. 31 shows Embodiment 2 of the present invention.
4 is shown. In the present embodiment, a radiator 26 for heat radiation is arranged in an air duct 25 near the ceiling. Normal,
Lighting fixtures are often installed near the ceiling. On the other hand, air ducts are often installed on the ceiling. There is always a flow of air inside this duct. Since the illumination module using the LED is very small and can be made thin, it can be made as a part of the air duct 25 as shown in FIG. In this case, the radiation fins 22 and the radiator 26 of the heat exchanger 24 as described in the above embodiment can be provided inside the duct 25. This makes it possible to provide a very compact lighting fixture in appearance. In addition, in order to prevent an overheating accident in the event that the ventilation in the duct stops, the wind pressure switch 27
The lighting fixture is turned off or dimmed when there is no air flow. The wind pressure switch 27 can be used not only to prevent accidents but also to actually control ON / OFF of the lighting equipment. The embodiments described here can be used not only for air ducts but also for piping of cooling water and air conditioning refrigerant.

(Embodiment 25) FIG. 32 shows Embodiment 2 of the present invention.
5 is shown. In some embodiments described above, the liquid cooling the light emitting element 1 and the substrate 2 stays inside the lamp module, and wastes heat using the lamp module housing 20, the heat radiation fins 22, the heat exchanger 24 and the like. Was. On the other hand, the present embodiment has a structure in which the liquid inside the lamp module is drawn out and cooled by providing a heat exchanger or the like outside. For this reason, the lamp module of the present embodiment has a structure in which the housing 20 is provided with connectors 28 and 29 for drawing out and drawing in the liquid. This embodiment is suitable when a large number of lamp modules are used side by side. Further, similarly to Example 24,
By providing a switch that detects the flow of liquid, it is possible to prevent overheating accidents and to turn on / off remote lighting.
FF operation may be enabled.

Embodiment 26 FIG. 33 shows Embodiment 2 of the present invention.
6 is shown. In the present embodiment, a light-receiving element 30 is provided on the back surface of the substrate 2 or the like, with an afterglow substance dispersed in the liquid 4 in the structure of the nineteenth embodiment or a similar structure. The light receiving element 30 monitors the light intensity, and changes the magnitude or the duty ratio of the current flowing through the light emitting element 1 by the control circuit 31 so that the light intensity becomes constant.
Although the light emitting intensity of the light emitting element 1 changes depending on the ambient temperature and a change with time, the light source device for illumination is required to keep the light flux unchanged for a long time. Therefore, it is preferable to actively control the light emission intensity by the means described here.

Conventionally, such control is performed by placing a light receiving element on a part of the LED mounting surface side. However, in this prior art, only information about a light emitting element near the light receiving element is placed. You will not get it. In addition, when components other than the light emitting element are mounted on the light emitting surface, designing becomes difficult due to the balance between light emission and light distribution. According to the embodiment described here,
The average light emission intensity of all light emitting elements can be monitored, and further, there is no need to mount components on the light emitting surface.

(Example 27) In Example 26 described above, the afterglow substance was dispersed in the liquid. However, since the purpose is to guide light to the back side of the substrate, light scattering particles are dispersed. You may let it. For example, silica fine particles or colloids can be used. Further, the inner surface of the housing of the lamp module may be painted white.

(Embodiment 28) Embodiment 26 or 27 described above
When the sensed light emission intensity becomes equal to or less than a certain value, the lifespan of the light emitting element or the failure is displayed. Alternatively, a signal notifying the fact is issued. The signal is transmitted by a data line, for example, to be centrally managed.

(Embodiment 29) Inside the lamp module described above, a blade for stirring the liquid is attached. This agitates the liquid and promotes cooling.

(Embodiment 30) A structure in which the lamp module described above rotates. By rotating the whole, the liquid inside is stirred. This can be implemented particularly easily in the case of decorative lighting in which light streaks move.

(Embodiment 31) In the lighting device as described in Embodiment 8, a plurality of particles for scattering light or converting wavelength are dispersed in a liquid. The liquid is agitated by screws or bubbles. This enables decorative lighting in which the liquid moves while shining in various colors. As described above, the heat transfer is promoted by the movement of the liquid.

[0052]

According to the present invention, the light emitting element is immersed in a liquid having an insulating property, an inert property, and a light transmitting property.
The cooling effect of the light emitting element was enhanced, and the efficiency and life were improved.
In addition, deterioration due to thermal stress was eliminated. In addition, deterioration due to coloring of the resin as in the related art is also eliminated. Further, various functions can be provided by dispersing and mixing various substances such as wavelength conversion properties, afterglow properties, and light scattering properties in a liquid.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a second embodiment of the present invention.

FIG. 3 is a sectional view of a third embodiment of the present invention.

FIG. 4 is a sectional view of a fourth embodiment of the present invention.

FIG. 5 is a characteristic diagram of a wavelength conversion substance used in Example 5 of the present invention.

FIG. 6 is a chromaticity diagram showing a designable range of a luminescent color according to a sixth embodiment of the present invention.

FIG. 7 is a sectional view of a seventh embodiment of the present invention.

FIG. 8 is a graph showing an afterglow characteristic of an afterglow substance used in Example 7 of the present invention.

FIG. 9 is a perspective view illustrating a basic configuration of an eighth embodiment of the present invention.

FIG. 10 is a perspective view showing a modification of the eighth embodiment of the present invention.

FIG. 11 is a perspective view showing another modification of the eighth embodiment of the present invention.

FIG. 12 is a sectional view of Embodiment 10 of the present invention.

FIG. 13 is a sectional view of Example 11 of the present invention when left still.

FIG. 14 is a cross-sectional view of Embodiment 11 of the present invention when vibrating.

FIG. 15 is a cross-sectional view of Example 13 of the present invention when placed vertically.

FIG. 16 is a cross-sectional view of Example 13 of the present invention when placed horizontally.

FIG. 17 is a perspective view of Embodiment 13 of the present invention as viewed from the front side.

FIG. 18 is a perspective view of Embodiment 13 of the present invention as viewed from the rear side.

FIG. 19 is a cross-sectional view at room temperature of Embodiment 16 of the present invention.

FIG. 20 is a sectional view of Example 16 of the present invention at a high temperature.

FIG. 21 is a perspective view of a seventeenth embodiment of the present invention.

FIG. 22 is a sectional view of Embodiment 17 of the present invention;

FIG. 23 is a front view when the lens plate of Embodiment 18 of the present invention is removed and the substrate is viewed.

FIG. 24 is a transverse sectional view showing a state where a lens plate according to Embodiment 18 of the present invention is mounted.

FIG. 25 is a longitudinal sectional view showing a state where a lens plate according to Embodiment 18 of the present invention is mounted.

FIG. 26 is a sectional view of Embodiment 19 of the invention.

FIG. 27 is a sectional view of Embodiment 20 of the present invention.

FIG. 28 is a sectional view of Embodiment 21 of the present invention.

FIG. 29 is a cross-sectional view of Embodiment 22 of the present invention.

FIG. 30 is a sectional view of Embodiment 23 of the present invention.

FIG. 31 is a sectional view of Embodiment 24 of the present invention.

FIG. 32 is a sectional view of Embodiment 25 of the present invention.

FIG. 33 is a sectional view of Embodiment 26 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Substrate 3 Frame 4 Liquid 5 Lens 6 Lens plate

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Jiro Hashizume, 1048 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. Reference) 5F041 AA03 AA33 DA20 DA74 DA77 DA81 FF11

Claims (10)

[Claims] 1. A light source device, wherein a light-emitting element is immersed in a liquid having an insulating property, an inert property, and a light-transmitting property. 2. The light source device according to claim 1, wherein a light emitting diode is used as the light emitting element. 3. The light source device according to claim 1, wherein the liquid or a substance dispersed in the liquid has a wavelength converting property. 4. The light source device according to claim 1, wherein the liquid or a substance dispersed in the liquid has afterglow. 5. The light source device according to claim 1, wherein the liquid or a substance dispersed in the liquid has light scattering properties. 6. The light source device according to claim 1, wherein the liquid or a substance dispersed in the liquid transmits only near the emission wavelength of the light emitting element. 7. The method according to claim 3, wherein
A light source device, wherein the specific gravity of a substance dispersed in a liquid is sufficiently different from that of the liquid. 8. The light source device according to claim 1, wherein the liquids used are liquids that have the same specific gravity at room temperature but are not compatible with each other, or a mixture of liquid and powder, and the two have different optical properties. 9. The liquid according to claim 1, wherein the liquid has a function of wavelength conversion, light scattering, or afterglow, or a substance having the function is dispersed or mixed in the liquid to form a liquid on the light emitting surface. A light source device characterized in that a plate is drawn on a surface in contact with a substance having water repellency to a part or all of a liquid. 10. The light source device according to claim 1, wherein a portion through which the heated liquid passes and a portion through which the cooled liquid passes are separated.