JPS60180180A - Infrared detection element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an infrared detection element that utilizes the pyroelectric effect of a ferroelectric thin film.

Conventional configuration and its problems Objects radiate infrared rays with a peak around a wavelength of 10 μm near room temperature, and the wavelength characteristics of this radiant energy vary depending on the temperature of the object, so the energy of the infrared rays radiated from the object By measuring , the temperature of an object can be measured without contact.

Infrared detectors used in these applications can be roughly divided into quantum type and thermal type.While quantum type has the advantage of fast response speed and high sensitivity, it requires cooling with liquid nitrogen, etc. This overcomes the drawback of high wavelength dependence of sensitivity.

In comparison, thermal detectors have lower sensitivity, but have the advantage of operating at room temperature and having no wavelength dependence of sensitivity. There are two types of thermal detectors: thermistor type and pyroelectric type, but pyroelectric type has relatively high sensitivity and does not require a bias power supply.
Easy to handle.

For these reasons, a pyroelectric detector with good characteristics is desired as an infrared detector.

Possible pyroelectric materials include single crystals, porcelain, and thin films.

Among these, thin films are advantageous in constructing a high-density array sensor, and are also advantageous in that they can increase specific detection ability.

Such a pyroelectric thin film is usually created by a high frequency sputtering method, a vapor deposition method, or the like using an oxide, 81, or the like as a substrate.

Pyroelectric infrared detectors utilize temperature rise due to absorption of infrared rays, so it is necessary to absorb sufficient infrared rays and prevent heat from escaping to the substrate. This is possible by attaching a film, while heat escape to the substrate can be solved by removing the substrate by etching or the like. However, the thin film is usually several micrometers thick and is very easily damaged, making it difficult to handle.

OBJECTS OF THE INVENTION The present invention solves the drawbacks of such a thin film device without a substrate, and in order to ensure sufficient absorption of infrared energy, at least one electrode surface is covered with an organic film mixed with an infrared absorbing material. The present invention provides a novel pyroelectric infrared detection element characterized by:

Structure of the Invention The infrared detecting element of the present invention, which achieves the above object, is a pyroelectric thin film from which a substrate has been removed, and at least one side of the pyroelectric thin film is coated with an organic film mixed with an infrared absorbing material.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. A magnesium oxide substrate (about 300 μm thick) is prepared using a sputtering apparatus.
A lead titanate thin film (2) with a thickness of 2 μm was grown on 1). Next, a platinum electrode (3) is vapor-deposited and formed at the center of the upper surface of the lead titanate thin film (2), and then an infrared absorbing material is mixed over the entire upper surface of the thin film (2) to a thickness of 0.5~
A 1.5 μm thick epoxy resin (4) was applied, and then the substrate (1) other than the outer periphery of the lower surface of the thin plate (2) was etched and removed using concentrated phosphoric acid, thereby forming the fourth part (6).

Next, a platinum electrode (5) was formed at the center of the lower surface of the thin film (2), facing the electrode (3), to produce an infrared detection element without a substrate. After fabrication, the device was polarized at 200° C. for 10 minutes with an electric field of total V 2 O/.

As the infrared absorbing material mixed into the epoxy resin (4), carbon, all black, and platinum black powders were used.

In this way, we obtained a glass element with a substrate coated with an organic film such as epoxy resin, and conducted a drop test on this element and another element coated with an organic film to examine the impact resistance. Approximately 30 elements without film
Even if dropped from the height of a pagoda, it was often damaged.

On the other hand, the element covered with organic film has 15
Even when dropped from a height of 0 Gm, no abnormality was observed.

Therefore, it was confirmed that a thin film device without a substrate coated with an organic film is sufficiently strong against shock S.

Next, the device was irradiated with infrared rays and the output voltage as an infrared detector was measured. As a means of measurement, peat 500
The synchrotron radiation from the blackbody reactor was chopped at 25Hz,
This was done by irradiating the device.

The output of the element was measured using a spectrum analyzer after impedance conversion was performed using a NET and then passed through a 60 dB amplifier.

Table 1 below shows an element without an organic film, an element coated with an organic film containing no infrared absorbing material, carbon at a volume ratio of 5.10.30%, platinum at 50 yen, full black at 30 yen, The output voltages of the elements coated with the mixed organic films are shown.

Table 1 As is clear from the above table, the sensitivity increased only slightly when an organic film was applied, but the sensitivity increased significantly when an organic film mixed with carbon, platinum black, or total black was applied. Furthermore, even when these infrared absorbing materials were mixed into the organic film, the device sufficiently withstood the impact force test described above.

Furthermore, when organic films are applied on both sides of the thin film,
The strength increased further. In the case of a device with a thin layer of organic film mixed with an infrared absorbing material on both sides, the output increased slightly.

Effects of the Invention As described above, according to the infrared detecting element of the present invention, an organic film mixed with an infrared absorbing material is coated on one or both sides of the pyroelectric thin film without a substrate, so it is resistant to mechanical impact force. It is extremely strong and easy to handle, and also has extremely good sensitivity.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view of the device, and FIG. 2 is a plan view. (1)...Substrate, (2)...Thin film, (3)(5)l
...electrode, (4)l...organic film. Figure 7 Figure 2

Claims (1)

[Claims] An infrared detection element in which the substrate of a ferroelectric thin film having a polarization axis perpendicular to the substrate surface is removed, and the surface of an electrode provided on one or both sides of the thin film is covered with an organic film mixed with an infrared absorbing material.