JP2011030463A - Underwater lighting, and culture device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellently pressure-resistant and long-lasting LED solid light which can be disposed under water; and to provide a culture device using the light. <P>SOLUTION: The underwater lighting 1 is structured by: implementing a blue LED 13a and a red LED 13b to a glass substrate 11 provided with a circuit pattern 12 respectively with flip chips; and forming a glass sealing part 14 made of fused glass closely attached to the LEDs to integrally seal them, so as to promote photosynthesis of algae having chlorophyll. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an LED solid-state illumination that can be installed in water, and a technique for promoting photosynthesis of aquatic plants, seaweeds, and the like by LED solid-state illumination.

In recent years, a technique for irradiating plants with monochromatic light such as LED light to promote growth and cultivate has attracted attention.
Plants grow using photosynthesis using carbon dioxide as a carbon source and light as an energy source. Therefore, plant growth can be promoted if light that can be easily taken up and absorbed can be efficiently supplied to a photosynthetic pigment (such as chlorophyll, carotenoid, and phycobilin) that performs photosynthesis.

FIG. 1 shows the light absorption spectra of chlorophyll a and b. Chlorophyll has strong light absorption in the wavelength region of blue light of 400 to 480 nm and red light of 600 to 700 nm. For this reason, the growth of a plant can be promoted by using a blue LED and a red LED as a light supply source (Patent Document 1).
Patent Document 2 also proposes a technique for purifying water by growing photosynthetic bacteria in water with near-infrared light of 800 nm or more.

There is a technique for applying these principles to promote photosynthesis and plant growth by irradiating an underwater plant with LED light for cultivation.
In plants inhabiting underwater such as aquatic plants and seaweeds, external light such as sunlight is absorbed and scattered by water, so that it is difficult to carry out photosynthesis particularly in deep water areas.

  In view of the above problems, as a means for effectively supplying light into the water, it is conceivable to illuminate the light in the water and irradiate light from closer to the plant. As such illumination, Patent Document 3 discloses LED solid-state illumination in which LEDs are arranged in a linear form and housed in a case body to have a waterproof structure.

JP-A-8-103167 Utility model registration 3073908 JP2009-022197

  In the LED solid state illumination described in Patent Document 3, since the LED is sealed with a transparent resin, the transparent resin is deteriorated (turbidized) by the LED light and is not suitable for long-time use. Furthermore, since the linear LED light source part has a waterproof structure in which the acrylic lid member and the case body are hermetically sealed, air (a gas such as an inert gas or a vacuum state) is provided between the light source part and the acrylic lid member. Thus, the light emitted from the LED is reflected by the difference in refractive index at each interface, and the light cannot be emitted effectively. Moreover, since it becomes the structure insulated by the inside and outside of a case body by this air, heat accumulates in a case body and the luminous efficiency of LED falls.

In such lighting with an inert gas filled inside or lighting in a vacuum atmosphere as described above, high-strength and large-scale extremely expensive cases such as pressure-resistant glass are used to withstand water pressure and external impact. Need to be used, which increases the cost.
Moreover, only the light source part described in Patent Document 3, for example, that does not perform gas sealing or vacuum formation, that is, the LED is simply sealed with a transparent resin such as epoxy or silicone, is applied as an underwater lamp. In this case, the sealing resin is shrunk / compressed by the water pressure, and a load is applied to the wiring portion such as LED and wire inside the resin, causing problems such as peeling or disconnection of the sealing resin. In addition, problems such as the deterioration of the sealing resin due to salt content occur in seawater.

  An object of this invention is to provide the LED solid-state illumination with the high pressure | voltage resistance and long life which can be installed in water in view of the above-mentioned problem, and a culture apparatus using the same.

  In order to achieve the above object, the present invention provides an underwater illumination in which a plurality of blue LEDs and red LEDs are arranged on a glass substrate and are integrally sealed with heat-sealing glass to form a glass sealing portion. It is characterized by.

According to the present invention, the underwater illumination itself sealed with the heat-sealing glass has a waterproof function, the structure is greatly simplified, and a small underwater illumination can be obtained at low cost.
In addition to suppressing deterioration due to light and heat by using a glass sealing part, use a large waterproof case to damage or destroy underwater lighting due to penetration of impurities such as chlorine contained in water into the interior. It can prevent without.
Furthermore, the glass sealing part and the LED, and the glass sealing part and the substrate are tightly sealed so that air does not enter, and the sealing is performed integrally. Can reduce light loss due to total reflection at the interface.

The light absorption spectrum of chlorophyll is shown. It is a model explanatory view which constituted a culture device with underwater lighting of the present invention. It is an expansion perspective view of the underwater illumination of this invention. It is drawing which showed the internal structure of the underwater illumination of this invention. It is drawing explaining the manufacturing method of the underwater illumination of this invention.

2 to 5 show an embodiment of the present invention.
As shown in FIG. 2, the underwater illumination 1 of the present invention is submerged in water and disposed near the plant 2 in seawater, so that light is supplied from closer to the plant to promote photosynthesis. An external power supply 4 that controls and supplies power is connected to the underwater lighting 1 that is submerged in water via a cable 3. Providing the external power supply 4 with a waterproof function is not preferable in terms of cost, and is therefore arranged outside so as not to touch seawater. However, by adopting such a configuration, a large number of underwater lights 1 are connected to an external power source 4 having a plurality of terminals (ports), and the lighting of the entire aquaculture device can be collectively controlled by a single external power source 4. Is also possible.
The aquaculture apparatus of the present invention is configured as described above.

Next, the underwater illumination 1 of the present invention will be described with reference to FIGS.
The basic configuration of the underwater illumination 1 includes a glass substrate 11, a circuit pattern 12, an LED 13, and a glass sealing portion 14.
(LED13)

  The LED 13 includes a blue LED 13a that emits blue light and a red LED 13b that emits red light. The blue LED 13a and the red LED 13b can promote plant photosynthesis and growth. In addition, an ultraviolet LED that emits ultraviolet light may be added. This is because underwater bacteria harmful to the plant 2 can be sterilized with ultraviolet light to assist plant growth.

  The blue LED 13a and the above-described ultraviolet LED are formed by epitaxially growing an InGaAlN group III nitride semiconductor on the surface of a growth substrate made of sapphire (Al2O3), whereby a buffer layer, an n-type layer, an MQW layer, The p-type layer is formed in this order. The blue LED 13a grows at 700 ° C. or higher, has a heat resistant temperature of 600 ° C. or higher, and is stable with respect to a processing temperature in sealing processing using a low-melting glass sealing portion 14 described later. The blue LED 13a is flip-chip mounted on the glass substrate 11 on which the circuit pattern 12 is formed via Au bumps.

The red LED 13b is made of a III-V group semiconductor such as GaAs. For this reason, the growth temperature is lower than that of the blue LED 13a, and there may be a case where the growth temperature cannot withstand the processing temperature of sealing processing using a heat-sealing glass described later.
For this reason, if importance is attached to the stability with respect to the processing temperature, it is preferable to use a group III nitride semiconductor similar to the blue LED 13a, but the current luminous efficiency is lower than that of the GaAs system. Therefore, it is preferable to use a group III nitride semiconductor and a GaAs system as required from the viewpoint of luminous efficiency and productivity.

The red LED 13b is generally called a vertical type (or vertical type, vertical type, etc.) and has many electrodes formed on the upper and lower surfaces of the chip. In this case, since one of the electrodes is connected by wire, the wire is crushed and broken at the time of sealing with heat-bonding glass described later. Therefore, similarly to the blue LED 13a, the red LED 13b is preferably flip-chip mounted using a chip in which an n electrode and a p electrode are formed on one surface.
(Glass substrate 11, circuit pattern 12)

The glass substrate 11 is made of ZnO—SiO 2 —R 2 O glass. A circuit pattern 12 is formed on the surface according to the electrode shape of the LED 13.
As the glass substrate 11, a polycrystalline sintered material such as sol-gel glass or ceramics can also be used. However, the sintered material is made of a porous body and has innumerable pores. For this reason, since a waterproof function falls as underwater illumination, it is unpreferable for long-time use. For this reason, it is preferable to use the heat sealing | fusion glass similar to the below-mentioned glass sealing part 14 with few holes per unit area (volume). This is because the use of heat-sealing glass increases the waterproof property and also has transparency, so that the light of the LED 13 is also emitted from the glass substrate 11 side, and the surrounding plants 2 can be illuminated and cultivated with a smaller number.

In this embodiment, the circuit pattern 12 has a structure in which three series-connected LEDs 13 are connected in parallel in three rows. In general, the drive voltage of an LED is determined by its composition, and the InGaAlN blue LED 13a of the present application is 3.0 to 3.5V, and the GaAs red LED 13b is 2.5 to 3.0V. For this reason, when these LEDs 13 are simply connected in parallel, the value of the current flowing through each LED 13 is greatly different from a desired value, resulting in a difference in luminance or causing a failure.
For this reason, it is possible to adjust the current value by inserting a resistance element (not shown) or change the number of mounted blue LEDs 13a and red LEDs 13b so that the voltage and current value applied to each LED 13 are within a desired range. Alternatively, although the two-terminal underwater illumination 1 is used in the present embodiment, the blue LED 13a and the red LED 13b may be separately driven and controlled as a four-terminal type.
(Glass sealing part 14)

The glass sealing portion 14 is formed by hot press processing in which the heat-sealing glass is heated and softened, and the LED 13 contacts and presses the glass substrate 11 flip-chip mounted on the circuit pattern 12 via the Au bump. The heat-sealing glass is a ZnO—B 2 O 3 —SiO 2 —Nb 2 O 5 —Li 2 O glass. In addition, the composition of glass is not limited to this, For example, it does not need to contain Li2O and may contain ZrO2, TiO2 etc. as an arbitrary component.
This thermally fused glass has a glass transition temperature Tg of 490 ° C., a yield point At of 520 ° C., and a softening point of 545 ° C., and a glass transition temperature Tg of 200 ° C. or lower than the epitaxial growth temperature of the blue LED 13a. .
Further, the thermal expansion coefficient α at 100 ° C. to 300 ° C. of the heat-sealing glass is 6 × 10 −6 / ° C. The coefficient of thermal expansion α is larger when the glass transition temperature Tg is exceeded. As a result, the heat-sealing glass is bonded to the glass substrate 11 at about 550 ° C., and hot pressing is possible.

  Since the glass sealing portion 14 made of the heat-sealing glass is softened and melted and is in close contact with the glass substrate 11, no gap is formed at the interface. For this reason, it becomes possible to obtain the underwater illumination 1 excellent in waterproofness. Moreover, by using heat-sealing glass for the glass substrate 11, the surface of the glass substrate 11 is also softened during hot press processing, so that the glass substrate 11 can be more securely sealed with no gap. With such a configuration, waterproofness can be further improved.

  Examples of the glass having a relatively low glass transition temperature Tg and a relatively small coefficient of thermal expansion include, for example, ZnO—SiO 2 —R 2 O (where R is at least one selected from Group I elements such as Li, Na, and K). Glass, phosphate glass and lead glass can be mentioned. Of these glasses, ZnO—SiO 2 —R 2 O glass is preferable because it has better moisture resistance than phosphoric acid glass and does not cause environmental problems like lead glass. Moreover, since the glass transition temperature is low, the productivity of the sealing process in the above-described red LED 13b is improved, and the range of selection is widened.

  Here, the heat-fusible glass is glass that is molded in a softened state by heating, and is different from glass that is molded by a sol-gel method. Since the sol-gel glass has a large volume change at the time of molding, cracks are likely to occur, and it is difficult to form a thick film of glass. However, the heat-fused glass can avoid this problem. Further, since the sol-gel glass generates pores, airtightness may be impaired. However, the heat-sealed glass does not cause this problem, and the LED 13 can be accurately sealed. For this reason, the underwater illumination 1 excellent in waterproofness can be obtained.

The underwater lighting 1 configured as described above can easily ensure waterproofness while the structure is simplified as compared with a conventional resin-sealed lighting device.
In addition, since the entire underwater illumination 1 is composed of a circuit formed of heat-fused glass or a metal pattern, and can be configured without containing organic matter inside, it can be a light source that is extremely stable against light and heat. I can do it.
Furthermore, between the glass substrate 11, LED13, and the glass sealing part 14 adhere | attaches by hot press processing, and water pressure resistance is also provided by forming so that gas etc. may not be contained inside.

In the present embodiment, the LED 13 using the blue LED 13a and the red LED 13b is shown in order to irradiate two light absorption bands of chlorophyll.
However, when irradiating the carotenoid and phycobilin, which are photosynthetic pigments other than chlorophyll, LEDs 13 that emit light in the wavelength regions of the respective light absorption bands must be used. Carotenoids have a light absorption band in the green to blue region, and phycobilin strongly absorbs light in the green region. For this reason, blue LEDs and / or green LEDs are used for plants containing carotenoids, and green LEDs are used for plants such as algae that contain a large amount of phycobilin. Can be made.

  In addition, the form mentioned above shows the one aspect | mode of this invention to the last, and can be suitably deform | transformed and applied within the scope of the present invention.

  The underwater lighting of the present invention can be applied as a seaweed aquaculture device, and can also be applied to uses such as lighting and illumination used by being submerged in water.

DESCRIPTION OF SYMBOLS 1 Underwater lighting 2 Plant 3 Cable 4 External power supply 11 Glass substrate 12 Circuit pattern 13 LED
14 Glass sealing part

Claims (5)

Underwater lighting that is placed underwater or submerged in seawater and promotes photosynthesis of algae with chlorophyll by the emitted light,
A glass substrate on which a circuit pattern is formed;
A plurality of blue and red LEDs arranged on the glass substrate and conductively connected to the circuit pattern;
A glass sealing portion made of heat-sealing glass that is in close contact with and integrally seals with the blue LED and the red LED and the surface side of the glass substrate on which they are mounted;
Underwater lighting with.   The underwater illumination according to claim 1, wherein the red LED is flip-chip mounted on the circuit pattern. An apparatus for cultivating underwater plants using the underwater illumination according to claim 1 or 2,
The underwater lighting arranged submerged in the sea water;
An external power source disposed outside the seawater to control power supplied to the underwater lighting;
A cable for connecting the underwater illumination and the external power source to each other;
An aquaculture device characterized by comprising: The glass sealing portion further integrally seals the ultraviolet LED disposed on the glass substrate,
The aquaculture apparatus according to claim 3, wherein bacteria in the seawater are sterilized by light emitted from the ultraviolet LED. In underwater lighting that is placed in seawater and promotes photosynthesis of algae with phycobilin,
A glass substrate on which a circuit pattern is formed;
A plurality of green LEDs arranged on the glass substrate and conductively connected to the circuit pattern;
A glass sealing portion made of heat-sealing glass that is in close contact with and integrally seals with the green LED and the surface side of the glass substrate on which these are mounted;
Underwater lighting with

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