JPS5838549Y2 - Sekigai Hoshiyagen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is primarily concerned with radiation sources, specifically planar sources of infrared radiation.

As smaller portable instruments are designed using infrared radiation sources, the development of infrared sources with high overall efficiency has become important.

One currently known infrared source is the Nernst phosphor, which uses a silicon carbide filament.

These emitters are difficult to start and operate, and coiled filament tungsten, whose physical arrangement does not provide the necessary good light source, is also used to obtain infrared radiation.

However, tungsten coil filaments are not suitable for use in equipment requiring low noise and yet good imaging.

Because of the physical placement of the coils, the image is in areas of radiation mixed with areas of no radiation, rather than solid areas of radiation.

Such images are said to have an inferior fill factor.

Additionally, devices using coiled filaments are prone to errors due to machine movement or device vibration.

When the device vibrates, the coil filament sways and generates spurious noise in the detected radiation.

Additionally, tungsten, which is commonly used in coiled filaments, has a relatively low emissivity in the infrared region (approximately 15), making it less suitable as an infrared source.

The above problems with coiled filaments are avoided by using a tungsten ribbon as the source.

However, even with the ribbon, tungsten, which has a low emissivity, still had to be used as an infrared radiation source.

Furthermore, the low resistivity of tungsten eliminates the boundary between the source and the conducting wire, and therefore it is difficult to obtain a small and very obvious source with tungsten nobons.

If a sloppy tungsten source is used with a stiff, thin wire current conductor, more power is wasted than with a lower resistance source, and the efficiency of the source is therefore lower. bad.

Another radiation source that is currently being talked about is light emitting diodes (LEDs).

However, current LEDs have very low power and are not suitable for all uses.

Accordingly, the present invention seeks to provide a compact, well-defined infrared radiation source that can be easily and effectively imaged.

According to the present invention, a high emissivity thin film resistive heater such as Cr3Si is deposited on the substrate.

The resistance heater is formed in a small portion between a pair of metal conductors provided on the substrate.

Since the thin film heater has a high emissivity and the material of the substrate has a low thermal conductivity, it becomes a very effective radiation source.

A resistive heater with high emissivity is placed between and adjacent to a pair of metal conductors.

The metal conductor has low resistivity and emissivity, and can provide a well-defined source suitable for imaging with a mirror.

Furthermore, since the radiation source is flat, it can be easily visualized, and furthermore, it is mechanically stable and is resistant to shocks.

In one embodiment of the invention, the resistive part is coated with an anti-reflection layer to increase the emissivity.

A source constructed in accordance with the present invention has an efficiency of about 2% in the infrared region with a bandwidth of 5%.

FIG. 1 is a schematic diagram of a radiation source according to an embodiment of the present invention.

In the figure, substrate 11 is made of a material with low thermal conductivity, such as thin film sapphire, Y2O3 or quartz.

The dimensions of the substrate 11 are selected depending on the size of the light source, and an example is approximately 3.8 x 0.5 x O, 05 mm.

The central portion 13 in the longitudinal direction of the substrate 11 forms a radiation source section, which has a resistivity and an emissivity (which is greater than 0.5).
This is a high area.

The radiation source section 13 has Cr3Si on the substrate 11 of about 1 to 2 μm.
Deposit it to a thickness of .

In this embodiment, the radiation source section 13 is a 0.5 x 0.5 mm rectangle, and its resistance value is about 100,! It is Q square.

In the infrared radiation part, the wavelength is 4μ and the emissivity of Cr3Si is about 0.5.

A pair of metal conductors 15 are arranged adjacent to both sides of the radiation source section 13.
is arranged, and its emissivity is Cr in the infrared region.
Low emissivity compared to 3Si.

Platinum has a suitable emissivity in the infrared region of about 0.1, but other metals such as gold may also be used.

The edge portions 17 of both metal conductors 15 are connected to the radiation source portion 1, respectively.
It overlaps with the end edge of 3.

Such an arrangement makes it possible to obtain a very clear source section.

Further, a pair of conductive wires 19 made of a material such as gold are connected to the conductor 15.
form input and output conductors that are connected to the line source section 13 to supply power to the line source section 13.

Note that, as will be explained below, spurious radiation is caused by the substrate 11.
A metal layer 21 is added to the bottom of the substrate 11 to prevent this spurious radiation since it is better not to radiate from the bottom of the substrate 11 or the like.

In operation, current conductor 19 is first connected to a power source that provides sufficient current to heat thin film resistor 13 to approximately 700 DEG C.

Approximately 50-70 mA of current is required to obtain adequate heat in the 100Ω square of Cr3Si.

Spurious radiation from the metal conductor 15 is kept to a minimum by using a very low thermal conductivity substrate, where a small amount of heat is passed from the source section 13 through the substrate 11 to the metal conductor 1.
5 will be informed.

Furthermore, by using gold with low emissivity, such as platinum, as the metal conductor 15 adjacent to the radiation source part 13 forming the resistance heater, radiation from the conductor 15 is reduced, and as a result, the part that generates radiation is placed in a space. becomes clear.

FIG. 2 is a schematic diagram of a light source according to another embodiment of the present invention.

The figure also shows a part of the substrate 11, but the metal conductor 15
A raised portion 17 is formed at the end of the metal conductor 15, and the thin film resistance heater 13 is adjacent to the metal conductor 15.

In addition, in FIG. 2, an antireflection layer 23 such as TiO2
is in contact with the resistance heater 13 with a thickness of about 44 μm.

Here, the antireflection layer 23 effectively increases the emissivity of the infrared source.

The material of the antireflection layer 23 has a refractive index that is higher than that of the heater 13.
is chosen to be approximately equal to the square root of the refractive index of the material.

FIG. 3 is a sectional view of a package in which a light source according to the present invention is mounted.

The figure shows the substrate 11 encapsulated in an optical package 25 .

The package 25 includes a housing 27 on which a reflective surface 29 is attached.

The reflective surface 29 is preferably an elliptical or parabolic reflective surface made of a solid piece of aluminum or the like.

A pair of metal struts 31 supply power to a line source 13 connected to a conducting wire 19 through a housing 27 and a reflective surface 29.

The infrared radiation generated by the source section 13 is guided to the reflective surface 29 and reflected from the package 25 to project a magnified image (not shown).

As is clear from this figure, the light emitted from the side of the radiation source 13 away from the reflective surface 29 is guided to the right side in the figure, and the image obtained by the light beam reflected from the reflective surface 29 is degraded. .

Therefore, as discussed with respect to FIG. 1, a metal layer is deposited behind the substrate 11 (on the right side of the figure) to prevent the generation of spurious radiation.

Note that the package 25 is desirably filled with an inert gas such as nitrogen or argon, and sealed in order to extend the life of the filament.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a radiation source according to an embodiment of the present invention;
FIG. 2 is a schematic configuration diagram of a light source according to another embodiment, in which 11 is a substrate, 13 is a line source section, 15 is a metal conductor, and 19 is a conducting wire. FIG. 3 is a cross-sectional view of a package in which the light source of the present invention is mounted, where 25 is a package, 27 is a housing, 29 is a reflective surface, and 31
is a metal support.

Claims (1)

[Scope of utility model registration request] A substrate made of a material with low thermal conductivity such as sapphire or crystal, a radiation source portion having an emissivity of 0.5 or more formed by a Cr3Si layer deposited on the substrate, and both ends of the radiation source portion. a pair of metal conductors having an emissivity of 0.2 or less, overlapping the edges and disposed on one surface of the substrate; and a pair of metal conductors coated on the Cr3Si to increase the effective emissivity of the radiation source section. an anti-reflective layer of material; a metal layer deposited on the other surface of the substrate to prevent spurious radiation; and a power conductor and output conductor electrically connected to the pair of metal conductors. An infrared radiation source consisting of