JPH04342438A - Infrared ray transmitting glass and infrared ray detecting sensor using the same - Google Patents

Abstract

PURPOSE:To provide an infrared ray transmitting material, excellent in transmittance of infrared rays to visible rays, hardly crystallizable without any toxicity and capable of readily producing lenses by press forming. CONSTITUTION:A human body sensor is obtained by using germanium and sulfur as principal components and arranging an infrared ray concentrating lens formed from an infrared ray transmitting glass prepared by using a glass containing iodine, antimony, tellurium and selenium for suppressing extension of an infrared ray transmitting region and crystallization of the glass in the front surface. The objective readily assembled inexpensive human body detecting sensor without any toxicity can be provided by combination of the aforementioned glass with a pyroelectric type infrared sensors.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a human body detection sensor comprising an infrared transmitting lens made of a non-oxide material and a pyroelectric infrared sensor using this lens as a condensing lens.

0002

2. Description of the Related Art Human body detection sensors using pyroelectric infrared sensors are widely used in home appliances and industrial equipment. Examples include automatic opening and closing of doors as people enter and exit, automatic faucets for flush toilets, and directional control of cold air from air conditioners. Generally, such a human body detection sensor is provided with a filter that transmits only infrared light in order to efficiently collect infrared rays of 8 to 12 μm emitted from the human body in front of the sensor. Traditionally, silicon,
Germanium and metal halides were used.

Furthermore, in recent years, attempts have been made to make a lens in front of a pyroelectric infrared sensor using a material that transmits only infrared light to not only detect the presence or absence of a human body but also to measure the number of people and body temperature. ing. For such applications, it has been dangerous and difficult to fabricate lenses using conventional materials. FIG. 2 shows an example of such a human body detection sensor, in which a plurality of pyroelectric infrared sensors 11 are arranged horizontally, and a lens 1
A lens driver (not shown) for moving the lens 2 left and right to send an image to the pyroelectric infrared sensor 11 is provided in a direction perpendicular to the lens. The generated voltage is taken out by the electrode 13, but in order to make it easier to amplify the infrared signal, a chopper driver 15 is used.
The intensity of the incident light is modulated by the chopper 14, which is rotated by the chopper 14. Further, the sensor 11 is supported by a support rod 16, and the sensor 11 is supported by a support rod 16.
The signal is transmitted through the lead wire 17.

Conventionally, chalcogenide glass, which is an infrared-transmissive glass that can be easily formed into a lens, has attracted attention as a condensing lens for such an infrared sensor. Chalcogenide glass is a glass whose main components are chalcogen elements (sulfur, selenium, tellurium), and in practical terms, arsenic-sulfur, germanium-arsenic-selenium, germanium-selenium-tellurium, and germanium-selenium-antimony are mainly studied. (For example, 31st Glass Symposium Abstracts, p. 71-74 (1990)). However, the first two
The glass contained arsenic, which caused toxicity problems. Furthermore, since the latter two hardly transmit visible light, it is impossible to visually align the optical axis between the lens and sensor when assembling the sensor, and an expensive infrared imaging device costing tens of millions of yen is required. Ta.

[0005]

[Problems to be Solved by the Invention] However, with such a conventional configuration, lenses using silicon or germanium had problems such as low transmittance of infrared rays of 8 to 12 μm and high material cost. . For example, the transmittance of 2 mm thick silicon at 10 μm is 45%, which is considerably lower than the 75% transmittance of silver chloride, which is one of the metal halides, and has been a cause of sensor malfunction. In addition, the cost of germanium is approximately three times that of high-purity silicon (
(approximately 250,000 yen per kilogram), which hindered widespread application. Furthermore, there is a problem in that germanium is easily oxidized by water vapor, causing a decrease in infrared transmittance.

On the other hand, conventional metal halides have high infrared transmittance, but have problems with light resistance and toxicity. For example, silver chloride has a transmission range of 0.4 to 28 μm and transmits almost all visible light to infrared light, but it is sensitive to ultraviolet light with a wavelength of 0.4 μm or less, precipitates silver, and quickly turns black. , the transmittance of infrared rays was also reduced. In order to prevent this blackening caused by ultraviolet rays, it was necessary to provide an ultraviolet shielding film such as antimony sulfide on the lens surface. As a result, a new problem occurred in that no visible light was transmitted. In addition, the well-known KRS-5 (a mixture of thallium bromide and thallium iodide) has a transmission range of 0.5 to 4
0 μm, it transmits almost all visible light to infrared light,
The problem was that thallium was extremely toxic.

[0007] Chalcogenide glass is a glass whose main components are chalcogen elements (sulfur, selenium, tellurium), and in practical use, arsenic-sulfur, germanium-arsenic-selenium, germanium-selenium-tellurium, germanium-selenium -Antimony has been mainly researched and developed, but the first two glasses contain arsenic and have a toxicity problem. Furthermore, since the latter two hardly transmit visible light, it was impossible to visually adjust the optical axis alignment of the lens and sensor during assembly, and an expensive infrared imaging device costing tens of millions of yen was required. . Additionally, this material tends to crystallize when reheated, making it difficult to form lenses by press molding.

The present invention solves these problems by creating a lens that transmits infrared rays of 8 to 12 μm emitted from the human body as well as visible light, is non-toxic, does not easily crystallize, and can be easily made into lenses by press molding. The purpose of this invention is to realize an infrared transmitting material with excellent chemical durability, and to provide an infrared sensor using this infrared transmitting lens.

[0009]

[Means for Solving the Problem] In order to solve this problem, the present invention uses a non-oxide as a starting material and constitutes an infrared transmitting lens using a non-oxide glass mainly containing germanium and sulfur. It is something.

[0010] Also, germanium 5 to 55% in atomic %
The infrared transmitting lens is made of glass mainly containing 35 to 90% sulfur and 0 to 20% iodine.

[0011] Also, germanium 15 to 50 in atomic %
%, 50 to 80% sulfur, and 0 to 10% antimony to form an infrared transmitting lens.

[0012] Also, germanium 10 to 25 in atomic %
%, 70 to 90% sulfur, and 0 to 10% tellurium to form an infrared transmitting lens.

[0013] In atomic %, germanium is 5 to 55%, sulfur is 35 to 80%, and either selenium or tellurium is 0 to 5%.
The infrared transmitting lens is made of glass mainly containing 10% iodine and 0 to 20% iodine.

Further, an infrared detection sensor is constructed by concentrating infrared rays onto a pyroelectric infrared sensor using the above-mentioned infrared transmitting lens.

[0015]

[Operation] It has been found that by using an infrared lens with this configuration, a chalcogenide glass whose main component is a non-toxic element can be realized, and the above-mentioned problems can be solved. That is, the main elements of chalcogenide glass are sulfur, selenium, tellurium, germanium, arsenic, and antimony. Among these, arsenic and selenium are designated as poisonous substances, and arsenic is said to be particularly toxic. Since selenium is abundant in tomato juice and is an essential nutrient for livestock, it is thought to have low toxicity. If we include elements other than arsenic and also allow visible light to pass through, the main components will be germanium and sulfur. That is, a human body sensor consisting of a pyroelectric infrared sensor using a lens made of glass whose main components are at least germanium and sulfur is promising. In addition to germanium and sulfur, it is also effective to add iodine, antimony, tellurium, selenium, etc. to infrared transmitting glass in order to expand the infrared transmittance range and suppress crystallization. Furthermore, in order to optimize the coefficient of thermal expansion, it is desirable to include small amounts of lithium, sodium, copper, silver, boron, gallium, indium, silicon, tin, lead, bismuth, phosphorus, and bromine.

The composition of the infrared transmitting glass of the present invention was selected for the following reasons. In the germanium-sulfur-iodine system (Ge-S-I system, hereinafter the system is indicated by element symbol), germanium is other than 5-55% and sulfur is 35-90%.
It will not become vitrified in any other way. Moreover, if the iodine content exceeds 20%, visible light will no longer be transmitted. In the Ge-S-Sb system, vitrification does not occur unless the germanium content is 15 to 50% and the sulfur content is 50 to 80%. Moreover, if antimony exceeds 10%, visible light will no longer be transmitted. In the Ge-S-Te system, vitrification does not occur unless the germanium content is 10 to 25% and the sulfur content is 70 to 90%. Moreover, if tellurium exceeds 10%, visible light will not be transmitted. In the Ge-S-I-Se (or Te) system, germanium is 5-55% and sulfur is 35%.
Vitrification does not occur at concentrations other than ~80%. Furthermore, if selenium or tellurium exceeds 10% and iodine exceeds 20%, visible light will no longer be transmitted.

[0017] With the above structure, it is possible to realize a lens that transmits infrared light to visible light, is non-toxic, is difficult to crystallize, and can be press-molded.

[0018]

EXAMPLE It has been found that the above problems can be solved by using chalcogenide glass whose main component is non-toxic elements. The main elements of chalcogenide glass are sulfur, selenium, tellurium, germanium, arsenic, and antimony. Among these, arsenic and selenium are designated as poisonous substances, and arsenic is said to be particularly toxic. Selenium is contained in large amounts in tomato juice and is an essential nutrient for livestock, so it is thought to have low toxicity. From the elements excluding arsenic, germanium and sulfur become the main components, provided that visible light is also transmitted. That is, by using at least germanium and sulfur as main components, a human body sensor consisting of a pyroelectric infrared sensor using a lens made of infrared-transmitting glass can be realized. In addition to germanium and sulfur, glass also contains iodine and antimony to expand the infrared transmission range and suppress crystallization.
Adding tellurium, selenium, etc. is effective. Further, in order to optimize the coefficient of thermal expansion, it is desirable to contain small amounts of lithium, sodium, copper, silver, boron, gallium, indium, silicon, tin, lead, bismuth, phosphorus, and bromine.

(Example 1) Ge:S=25:7 in atomic %
Ge and S were weighed at a ratio of 5:5 and vacuum sealed in a quartz ampoule. This was melted in an electric furnace at 800° C. for 12 hours to obtain glass. The obtained glass is yellow to the naked eye, and a 2 mm thick sample (hereinafter the same) has an infrared ray of up to 10.5 μm.
% or more was transmitted.

(Example 2) Ge:S:I=30 in atomic %
Ge, S, and I were weighed at a ratio of :60:10 and vacuum-sealed in a quartz ampoule. This was melted in an electric furnace at 800° C. for 12 hours to obtain glass. The resulting glass was brown in color and 1
More than 50% of infrared rays up to 1 μm were transmitted. In addition, in this example, no vitrification occurred when Ge was other than 5 to 55% and S was 35 to 90%. Moreover, when I exceeded 20%, visible light was no longer transmitted.

(Example 3) Ge:S:Sb=3 in atomic %
Ge, S and Sb were weighed at a ratio of 0:60:10 and vacuum sealed in a quartz ampoule. This was heated to 950℃ in an electric furnace for 1
Glass was obtained by melting for 2 hours. The resulting glass was dark brown and transmitted more than 50% of infrared light up to 11 μm. In this example, Ge is 15 to 50% and S is 50 to 80%.
Vitrification does not occur at temperatures other than %. Moreover, when Sb exceeded 10%, visible light was no longer transmitted.

(Example 4) Ge:S:Te=2 in atomic %
Ge, S and Te in the ratio of 3.75:71.25:5.00
was weighed and vacuum sealed in a quartz ampoule. This was melted in an electric furnace at 900°C for 12 hours to obtain glass. The resulting glass was blue in color and transmitted over 50% of infrared light up to 11 μm. In this example, Ge is 10 to 25% and S
Vitrification does not occur when the amount is other than 70 to 90%. Moreover, when Te exceeds 10%, visible light no longer transmits.

(Example 5) Ge:S:I:Se in atomic %
= Ge and S in the ratio of 23.75:61.25:10.50
, I, and Se were weighed and vacuum-sealed in a quartz ampoule. This was melted in an electric furnace at 900°C for 12 hours to obtain glass. The resulting glass was blue in color and transmitted over 50% of infrared light up to 11 μm. In addition, in this example, Ge is 5~
Vitrification does not occur when S is other than 55% and S is 35 to 80%. Furthermore, if Se or Te exceeds 10%, and I exceeds 20%, visible light will no longer be transmitted.

(Example 6) The glasses of Examples 1 to 5 were
Although the glasses were immersed in hot water at ℃ for 1 hour, no surface deterioration was observed, confirming that these glasses had excellent chemical durability.

[0025] The glass of Example 1 was pressed at 400°C to form a lens. The thickness of the lens was approximately 2 mm, the F number was 1.0, and the focal length was 3 mm. Lead fluoride was deposited to a thickness of 1.4 μm on both sides of the lens to form an antireflection film. This lens was installed in front of ten pyroelectric infrared sensors arranged horizontally to form the human body detection sensor shown in FIG. The lens can be moved 120 degrees left and right. When two men stood 50cm apart in front of the sensor and examined the sensor output voltage while moving the lens, a voltage of approximately 200mV was generated when a human body was detected, confirming the sensor's performance.

[0026] Also, with the glasses of Examples 2 to 5, lenses were molded in the same way and sensor performance tests were conducted. The results were obtained.

(Embodiment 7) As an example of application to an air conditioner, as shown in FIG. 1, the infrared detection sensor 1 of Examples 1 to 5 was installed in the air conditioner body 2, and two men were placed in front of the air conditioner at a distance of 50 cm. The louver 3 was made to stand upright and alternately face the direction in which the human body 5 was detected. As a result, the air from the fan 4 is now directed toward the human body 5 through the louver 3 automatically in response to a signal from the sensor, without the user having to manually operate the louver.

Note that the application example of the infrared detection sensor of the present invention is not limited to the seventh embodiment, and in addition to the above embodiment, as an application to a lighting device, for example, a human body detection sensor may be installed on a gatepost light. The lights are then directed in the direction in which a human body is detected, making it easier to confirm the number of visitors at night. In addition, as an application to water supply equipment, for example, a human body detection sensor can be installed on a water faucet to direct the shower in the direction of multiple human bodies, so that people do not have to manually operate the shower opening. is also possible.

[0029]

[Effects of the Invention] The human body detection sensor of the present invention uses non-toxic chalcogenide glass that transmits visible light as an infrared light condensing lens, making it easy to assemble the sensor and detection device. Since lenses can be manufactured by molding, they are safe and inexpensive, so they can be widely used in consumer appliances and industrial equipment.

[Brief explanation of drawings]

[Figure 1] Configuration diagram of an air conditioner using the infrared detection sensor of the present invention

[Figure 2] Cross-sectional view of a conventional human body detection sensor

[Explanation of symbols]

1 Infrared detection sensor 2　Air conditioner body 3 Louver 4 Fan 5 Human body

Claims (6)

[Claims] 1. An infrared transmitting lens made of a non-oxide glass whose starting material is a non-oxide and whose main components are germanium and sulfur. 2. The infrared-transmissive lens according to claim 1, comprising a glass mainly containing, in atomic percent, 5 to 55% germanium, 35 to 90% sulfur, and 0 to 20% iodine. 3. The infrared transmitting lens according to claim 1, which is made of a glass mainly containing 15 to 50% germanium, 50 to 80% sulfur, and 0 to 10% antimony in atomic percent. 4. The infrared-transmissive lens according to claim 1, comprising a glass mainly containing 10 to 25% germanium, 70 to 90% sulfur, and 0 to 10% tellurium in atomic percent. Claim 5: 5 to 55% germanium, 35 to 80% sulfur, and 0 to 5% of either selenium or tellurium in atomic %.
2. The infrared transmitting lens according to claim 1, comprising glass mainly containing 10% of iodine and 0 to 20% of iodine. 6. An infrared detection sensor configured to condense infrared light onto a pyroelectric infrared sensor using the lens according to claim 1.