JP3102144B2 - Forced cooling light emitting diode device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode illuminating device having a forced cooling device.

[0002]

2. Description of the Related Art Light-emitting diodes are widely used in various display devices and the like because of their long life and the ability to obtain light of a desired wavelength in a narrow spectral width. Recently, these features have been used to grow and preserve various plants. When applied to these applications, the light emitting diode is not cooled particularly, but is naturally cooled at room temperature before use.

[0003]

However, when applied to such an application, particularly when used in a display device or a plant growing device used outdoors, a high luminous output is required. Also, it has been required to narrow the spectrum width of the emission wavelength from the viewpoint of effective use of light or purification of emission color.

[0004]

As a result of repeated studies, the present inventor has found that these problems can be solved by forcibly cooling the light emitting diode device, and has reached the present invention. The object of the present invention is to provide a heat-insulating case in which at least one surface is light-transmissive, wherein at least one surface accommodated in the heat-insulating case is light-transmissive, and a desired number of light-emitting diodes are accommodated therein. Cooling case, an inlet pipe for introducing a coolant from the outside of the heat insulating case into the cooling case, a discharge pipe for discharging the coolant from the inside of the cooling case to the outside of the heat insulating case, and driving power from the outside of the heat insulating case to the light emitting diode. Is achieved by a forced-cooled light-emitting diode arrangement consisting of connection lines supplying

FIG. 1 is a longitudinal sectional view of an example of a forced cooling light emitting diode device according to the present invention. In FIG. 1, reference numeral 1 denotes a heat insulating case. The material of the heat-insulating case 1 is not particularly limited as long as it can maintain appropriate rigidity, and a metal, glass, synthetic resin, or the like can be appropriately used. For heat insulation, the heat insulation case itself may be made of a heat insulating material. However, it is more appropriate to provide a space between the heat insulation case and the cooling case housed therein and fill the space with the heat insulation material.
As a heat insulating material, it is most suitable to maintain a vacuum, that is, to maintain the space in a vacuum, since the heat insulating performance is high and the light transmission is not hindered, but glass fiber or the like can also be used.

Reference numeral 2 denotes a light transmission window. The window 2 is necessary for extracting light generated by the light emitting diode to the outside. Note that the window does not need to be particularly provided when the heat-insulating case is made of a material having good light transmittance such as glass. 3 is a cooling case. The cooling case 3 is housed inside the heat insulating case 1 and is insulated from the outside. The cooling case needs at least one surface to be light-transmissive in order to take out the light generated by the light emitting diode to the outside. The material of the cooling case 3 may be the same as the material of the heat insulating case 1. The inside of the cooling case 3 is preferably −10 ° C. or less, more preferably −100 ° C., with a coolant.
It is cooled below.

Reference numeral 4 denotes an introduction pipe, and 5 denotes a discharge pipe. The coolant for cooling the cooling case 3 is introduced into the cooling case 3 from the introduction pipe 4, passes through the inside of the case, and is discharged from the discharge pipe 5 to the outside of the heat insulating case while cooling the light emitting diodes. The introduction pipe 4 and the discharge pipe 5 are arranged to penetrate the wall of the heat-insulating case 5 so that the coolant can be introduced and discharged from outside. The cooling agent is not particularly limited as long as it can cool the inside of the cooling case 3 to a desired temperature, but liquid nitrogen is most preferable from the viewpoint of easy handling, cooling capacity, and the like. In addition, liquid hydrogen, liquid helium, dry ice, or ethanol and other refrigerants cooled by an electronic cooling device or the like are used.

Reference numeral 6 denotes a light emitting diode. A desired number of light emitting diodes are used as needed. Further, the emission wavelength is appropriately selected according to the purpose of use. For example, when used in plant growing or preserving devices, it is preferable to use light emitting diodes that emit wavelengths useful for photosynthesis. For example, it is appropriate to use a gallium arsenide arsenide-aluminum-based double hetero-type light emitting diode which emits light at around 660 nm which is one of such wavelengths. The light-emitting diode is not limited to a normally used epoxy resin molded one, but may be a chip-shaped one.

Reference numeral 7 denotes a connection line for supplying drive power to the light emitting diode. When the connection line 7 passes through the wall of each case, it is necessary to electrically insulate as necessary. 8 is a temperature sensor. It is used as needed to measure the temperature inside cooling case 3. A thermocouple or the like is used as the temperature sensor. FIG. 3 shows the present invention.
However, the present invention is not limited to the one shown in FIG.

[0010]

EXAMPLE A gallium aluminum arsenide double hetero-type light emitting diode having a peak emission wavelength of 660 nm was used.
They were connected in series and housed in a cooling case housed inside a heat insulating case having the structure shown in FIG. Both the heat insulation case and the cooling case were made of fused quartz, and a vacuum was applied between the two cases to insulate them. As shown in FIG. 2, the output was measured for the case of cooling with liquid nitrogen and the case of emitting light at room temperature.

In FIG. 2, the vertical axis represents the light emission output (arbitrary unit), and the horizontal axis represents the drive current. 9 indicates a case where the sample was cooled with liquid nitrogen, and 10 indicates a case where the sample was measured at room temperature. As is clear from FIG. 2, when cooled, the current does not saturate even with a large current, and the output is improved about 75 times.

[0012]

[Effects] The present invention has the following effects, and is of great industrial utility value. (1) The light emission output is significantly improved as compared with the case of driving at room temperature. (2) The light emission output is hardly saturated even with a large current. (3) The spectral width also decreases.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of the device of the present invention.

FIG. 2 is an explanatory diagram showing a correlation between a drive current and a light emission output.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat insulation case 3 Cooling case 6 Light emitting diode 8 Temperature sensor

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 33/00 H01L 23/473

Claims (1)

(57) [Claims] 1. A heat insulating case in which at least one surface is light transmissive, and a cooling case in which at least one surface accommodated in the heat insulating case is light transmissive and a desired number of light emitting diodes are accommodated therein. A supply pipe for introducing a coolant into the cooling case from outside the heat insulating case, a discharge pipe for discharging the coolant from the cooling case to the outside of the heat insulating case, and supplying driving power to the light emitting diode from outside the heat insulating case. A forced cooling light emitting diode device comprising a connection line.