JP4134356B2 - Infrared light source - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an infrared light source having a microbridge-shaped filament on a silicon substrate.
[0002]
[Prior art]
The top view and AA sectional drawing of the conventional infrared light source are shown in FIG. Reference numeral 1 denotes a silicon substrate, on which a filament 2, a pedestal 3 on which the filament 2 is installed, an electrode 4 for passing a current through the filament 2, and a dug hole 5 are formed. The pedestal 3 is formed by excavating the pedestal 3 from the front or back surface of the silicon substrate 1 so as to selectively leave the pedestal 3 by wet etching. The filament 2 formed on the pedestal 3 may be a resistor such as a silicon single crystal, polysilicon, or a metal film.
[0003]
In the conventional infrared light source, a current is passed between the two electrodes 4 to heat the filament 2 to emit infrared rays.
[0004]
[Problems to be solved by the invention]
However, the infrared light source configured as described above has a problem that the directivity of the emitted infrared light cannot be controlled.
[0005]
The present invention has been made in view of the above points, and an object of the present invention is to provide an infrared light source capable of obtaining an infrared output having directivity.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 is an infrared light source comprising a silicon substrate , a filament formed by a microbridge on the silicon substrate, and an electrode for passing an electric current through the filament . A lens for controlling the straightness and directivity of infrared rays with a plano-convex shape in which the silicon substrate side is flat and the opposite surface is convex is added below a dug hole made by etching. To do.
[0007]
According to a second aspect of the present invention, in the infrared light source according to the first aspect, a reflective film for reflecting infrared light is provided on the filament.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an infrared light source according to an embodiment of the present invention.
[0009]
Reference numeral 1 denotes a silicon substrate, on which a filament 2, a pedestal 3 on which the filament 2 is installed, an electrode 4 for passing a current through the filament 2, and a dug hole 5 are formed. The pedestal 3 is formed by excavating the pedestal 3 from the front or back surface of the silicon substrate 1 so as to selectively leave the pedestal 3 by wet etching. For the filament 2 formed on the pedestal 3, a resistor such as a silicon single crystal, polysilicon, or a metal film is used.
[0010]
A lens 6 is added below the dug hole 5 formed by etching, and controls the straightness and directivity of the infrared output emitted from the lower part of the infrared light source. In addition, the thickness of the lens 6 can be made thin by using a Fresnel lens for the lens 6, and the size of the infrared light source can be made compact.
[0011]
Next, the operation of this embodiment will be described. When a current flows between the electrodes 4, the filament 2 is heated, and infrared rays corresponding to the temperature of the filament 2 are emitted. Here, the filament 2 emits infrared rays in almost all directions, but the lens 6 provided below the filament 2 polarizes the infrared rays radiated below the silicon substrate 1, so that straightness is achieved. It is possible to obtain high-output infrared rays by improving parallel light and outputting parallel light or collecting light.
[0012]
According to the present embodiment, since the focal length can be controlled by the lens 6, it is possible to radiate or condense infrared rays radiated from the lower surface of the silicon substrate 1 as parallel light from the surface of the silicon substrate 1.
[0013]
As shown in FIG. 2, by adding a reflective film 7 made of gold or the like that reflects infrared rays to the upper part of the filament 2, infrared rays radiated to the upper part of the filament 2 can be reflected downward of the filament 2. The amount of light incident on the lens 6 can be increased.
[0014]
【The invention's effect】
As described above, according to the first aspect of the present invention, in an infrared light source including a silicon substrate, a filament formed by a microbridge on the silicon substrate, and an electrode for passing a current through the filament, Then, a lens for controlling the straightness and directivity of infrared rays is added below the digging hole made by etching the silicon substrate with a plano-convex shape in which the silicon substrate side is flat and the opposite surface is convex. Therefore, since the focal length can be controlled by the lens, an infrared light source capable of obtaining an infrared output having directivity can be provided.
[0015]
In the invention described in claim 2, in the invention described in claim 1, since the reflective film for reflecting infrared rays is provided on the upper part of the filament, the infrared radiation radiated on the upper part of the filament is reflected downward of the filament. Therefore, the amount of light incident on the lens can be increased.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an infrared light source according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an infrared light source according to another embodiment of the present invention.
FIGS. 3A and 3B are a top view and a cross-sectional view taken along line AA of a conventional infrared light source. FIGS.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Filament 3 Base 4 Electrode 5 Excavation hole 6 Lens 7 Reflective film

Claims (2)

In an infrared light source comprising a silicon substrate , a filament formed by a microbridge on the silicon substrate, and an electrode for passing an electric current through the filament, a dug hole made by etching the silicon substrate below the filament the downward, infrared source, characterized in that so as to add a lens in which the silicon substrate side is controlled straightness and directivity of the infrared flat-convex opposite surface thereof has a convex shape flat.   2. The infrared light source according to claim 1, wherein a reflective film for reflecting infrared rays is provided on the filament.

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