JPH09230233A - Infrared wide-angle single lens, non-contact temperature measuring instrument and air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an infrared wide-angle single lens excellent in image- formation characteristic and having nearly uniform peripheral light quantity ratio characteristic. SOLUTION: In this single lens 1; d0 is a surface distance between a diaphragm and the 1st surface of the lens, d1 is the center thickness of the lens, (n) is the refractive index of glass material in 10μm wavelength, (f) is a focal distance, (bf) is a back focus, ideal image height at a relative field angle of 0.7 in the case the maximum field angle of a half field angle 60deg is set as 1 is y07, the main light beam image height of an actual light beam is y7, the ideal image height at the maximum filed angle is y01, and the main light beam image height of the actual light beam is y1. In such a case, when the respective field angles Dist0.7 and Dist1.0 are defined by following expressions, the following conditions are satisfied. Dist0.7=(y7-y07)/y07, Dist1.0=(y1-y01)/y01, (1) 0.15<d0/f<0.3, (2) 0.45<(d0+d1/n)/f<0.65, (3) 1.3<(d0+d1/n+bf)/f<1.5, (4) -0.25<Dist0.7<-0.2, (5)-0.5<Dist1.0<-0.45, and (6) 0.7<bf/f<1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared wide-angle single lens or the like mainly used in a non-contact temperature measuring device for detecting a temperature distribution condition in a room.

[0002]

2. Description of the Related Art Conventionally, an inexpensive single-element infrared detector is used in a non-contact temperature measuring device, and a thermal image is formed on the infrared detector by an infrared optical system having a narrow angle of view. . When observing a wide range, the temperature distribution in a two-dimensional area was measured by scanning with a swing mirror or the like. However, there is a problem that the structure is complicated and it is difficult to reduce the size and cost. As a conventional example, JP-A-53-4
There is 1279 publication. Hereinafter, an example of the above-described conventional non-contact temperature measuring device will be described with reference to the drawings.

FIG. 7 is a block diagram of a conventional non-contact temperature measuring device. The non-contact temperature measuring device 26 includes a motor 13 rotating at a constant speed, a rotary shaft 14 of the motor, a rotary disk 15, a pin 16, a reflecting mirror 17 for scanning, a supporting shaft 18, a connecting arm 19, an object to be measured 20, a reflecting mirror. 21, 22, a rotating sector 23 for connecting and disconnecting infrared rays, a condenser lens 24, and an infrared detector 25.

The rotational movement of the motor 13 is generated by the connecting arm 19
Is transmitted to the scanning reflecting mirror 17 via the
7 makes a reciprocating rocking motion. Infrared rays emitted from each point of the measuring object 20 scanned by the reciprocating swing movement of the scanning reflecting mirror 17 are reflected by the reflecting mirrors 21 and 22, and are collected by the condenser lens 24, and the infrared detector is provided. Sent to 25. The rotating sector 23 provided on the front surface of the infrared detector 25 is a motor 13
The slit is formed so that infrared rays can be transmitted only in one way of the reciprocating swing movement of the scanning reflecting mirror 17.

[0005]

However, with the above-mentioned structure, it is difficult to reduce the cost and the size, and there is a great limitation in mounting and incorporating the device. In recent years, research on inexpensive array-type or two-dimensional infrared detectors has progressed,
In the optical system used for this, as a conventional example of an infrared wide-angle lens for forming an image of a two-dimensional area on a detector at a time, Japanese Patent Laid-Open No. 6-9
There is a 4991 publication. However, the half angle of view is 35d
It was as small as eg and the observation range was narrow.

In view of the above-mentioned problems of the conventional detector, the present invention has a half-angle of view of 60 deg even though it is a single lens and realizes a good image forming characteristic in the entire image forming area, and at the same time, the variation width of the peripheral light amount ratio is increased. It is an object of the present invention to provide an infrared wide-angle single lens or the like having a maximum of about 20%.

[0007]

In order to solve the above problems, the infrared wide-angle single lens of the present invention is a biconvex lens having a stop on the object side, and d0 is the distance from the stop to the first lens surface. , D1 is the lens center thickness, bf is the back focus, n is the refractive index of the glass material at a wavelength of 10 μm, and f is the focal length, (1) 0.15 <d0 / f <0.3 (2) 0.45 <(D0 + d1 / n) / f <0.65 (3) 1.3 <(d0 + d1 / n + bf) / f <1.5 is provided.

Desirably, the distortion aberration at a relative angle of view of 0.7 when the maximum angle of view of a half angle of view of 60 deg is 1 is D
dist0.7, the distortion at the maximum angle of view Dist
When it is set to 1.0, (4) -0.25 <Dist0.7 <-0.2 (5) -0.5 <Dist1.0 <-0.45 is there. However,
Dist0.7 is y07 when the half angle of view is 60 deg and the ideal image height is 0.7 at the relative angle of view of 0.7, the principal ray image height of the real ray is y7, and the ideal image height at the maximum angle of view is y.
When 01 and the principal ray image height of the real ray are y1, the distortion is defined by the following equation.

Dist0.7 = (y7−y07) / y07 Dist1.0 = (y1−y01) / y01 More preferably, when bf is the back focus, (6) 0.7 <bf / f <1. It has a configuration that satisfies the conditions.

According to the present invention, with the above-described structure, an appropriate negative distortion aberration is generated, whereby the peripheral light amount ratio is made uniform, and the half field angle 60 is achieved even though it is a single lens.
It is possible to provide an infrared wide-angle single lens that achieves excellent image forming characteristics over the entire image area of deg, and that has an excellent performance with a variation range of the peripheral light amount ratio of about 20%. In particular, since the peripheral light amount ratio is substantially uniform, the temperature distribution of the measurement target is the same in the one-dimensional array or the two-dimensionally arranged infrared detection pixels forming the infrared detector. Infrared rays can be collected by the distribution. As a result, it is not necessary to correct the output of the infrared detector with the peripheral light amount ratio characteristic of the optical system, and a high S / N ratio can be obtained even in the peripheral portion of the image. In addition, because of good imaging characteristics and uniform peripheral light amount ratio characteristics from the center of the image to the peripheral portion, some decentering may occur in the optical axis alignment of the infrared wide-angle single lens and the infrared detector according to the present invention. Even if it occurs, an error is unlikely to occur in the measurement, and the assembly and adjustment are easy.

In order to obtain these excellent optical characteristics, the infrared wide-angle single lens according to the present invention is constructed so as to satisfy the above conditions.

The conditions (1), (2), and (3) define a range in which good imaging characteristics, uniform peripheral light amount ratio characteristics, and compactness can be realized at the same time.

If the lower limit of the condition (1) is exceeded, the chief ray height of the off-axis light beam to the lens surface will be small, and it will be difficult to generate distortion to the required extent, and the peripheral light amount ratio will decrease off-axis. However, it becomes difficult to make the peripheral light amount ratio uniform. In order to suppress this, if the radius of curvature of the second surface of the lens is made small and distortion is made to be large in the negative direction, coma is generated and the imaging characteristics are deteriorated. When the value exceeds the upper limit, the distortion aberration becomes negative more than necessary, and the peripheral light amount ratio tends to increase off-axis. Further, the upper ray of the off-axis light beam is undercorrected, and the coma aberration deteriorates.

When the value goes below the lower limit of the condition (2), the optical path length from the diaphragm to the lens second surface becomes small, and the chief ray height of the off-axis light beam at the lens second surface becomes small. As a result, negative distortion does not occur to the required extent, the peripheral light amount ratio decreases off-axis, and it becomes difficult to make the peripheral light amount ratio uniform. When the upper limit is exceeded, distortion tends to be more negatively biased than necessary,
The center thickness of the lens becomes large, and it becomes difficult to secure the back focus.

The condition (3) defines the distance from the diaphragm to the image plane. If the lower limit is exceeded, it is advantageous for compactness. However, the distance between the diaphragm and the lens first surface, the lens edge thickness, etc. Becomes too small, making processing and assembly difficult. If the upper limit is exceeded, downsizing becomes difficult.

The conditions (4) and (5) define the range of the amount of distortion generated that realizes a uniform peripheral light amount ratio characteristic. When the value goes below the lower limit of the condition (4), the negative distortion aberration in the intermediate field angle band becomes too large, and the peripheral light amount ratio tends to increase in the intermediate field angle band. At the maximum angle of view, the peripheral light amount ratio has a large positive deviation. To do. If the upper limit is exceeded, the negative distortion in the intermediate angle of view band becomes too small, and the peripheral light amount ratio tends to become insufficient. When the value goes below the lower limit of the condition (5), the peripheral light amount ratio is positively greatly deviated at the maximum field angle. If the upper limit is exceeded, the peripheral light amount ratio will be insufficient.

The condition (6) defines a range in which a necessary amount of air is secured between the infrared detector and the infrared detector used in combination with the infrared wide-angle single lens according to the present invention. If the value goes below the lower limit, the air gap between the infrared detector used in combination with the infrared wide-angle single lens becomes too small, which makes assembly and adjustment difficult. If the upper limit is exceeded, assembly and adjustment will be easy, but the device will be large.

The infrared wide-angle single lens according to the present invention is preferably made of silicon (Si). Generally, in addition to silicon, germanium (G) is used as a material having sufficient transmission characteristics in the infrared region with a wavelength of about 10 μm.
e), zinc selenide (ZnSe), etc., but they have a problem of high cost. On the contrary, silicon is mass-produced as a semiconductor material, and the cost as a lens material is low.

By combining the infrared wide-angle single lens according to the present invention and the infrared detector, it is possible to realize a non-contact temperature measuring device which is small in size, low in cost, and capable of accurately measuring the temperature distribution in a wide measuring range. Furthermore, by making the infrared detector a pyroelectric infrared detector that does not require cooling, it is possible to realize a small-sized, low-cost, non-contact temperature measuring device with good temperature resolution.

Further, by using the non-contact temperature measuring device, an air conditioner capable of detecting the position of the human body and measuring the temperature distribution of each area in the room and using the measurement result to perform optimum air conditioning control. It can be realized with small size and low cost.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In each embodiment, d
0 is the surface distance from the diaphragm to the lens first surface, d1 is the lens center thickness, r1 and r2 are the radii of curvature of the lens first and second surfaces, n is the refractive index of the glass material of the lens at a wavelength of 10 μm,
f is the focal length, Dist 0.7 and Dist 1.0 are the distortion aberration at the relative angle of view 0.7 and the distortion aberration at the maximum angle of view when the maximum angle of view is 1, and bf is the back focus. Next, conditions of each embodiment will be shown.

(First embodiment) F number: 1.4 Half angle of view = 60 deg f = 2.10 d0 / f = 0.25 (d0 + d1 / n) /f=0.55 (d0 + d1 / n + bf) / f = 1.48 Dist0.7 = −0.232 Dist1.0 = −0.479 bf / f = 0.92 d0 = 0.52 r1 = 20.274 d1 = 2.19 n = 3.4177 r2 = -6.258 (Second Embodiment) F number: 1.4 Half angle of view = 60 deg f = 1.77 d0 / f = 0.21 (d0 + d1 / n) /f=0.57 (d0 + d1 / n + bf) /F=1.43 Dist0.7 = -0.236 Dist1.0 = -0.489 bf / f = 0.86 d0 = 0.38 r1 = 10.742 d1 = 2.14 n = 3.4177 r2 = -6.105 (Third Embodiment F number: 1.4 Half angle of view = 60 deg f = 1.78 d0 / f = 0.22 (d0 + d1 / n) /f=0.57 (d0 + d1 / n + bf) /f=1.41 Dist0.7 =- 0.235 Dist1.0 = -0.488 bf / f = 0.84 d0 = 0.39 r1 = 9.360 d1 = 2.13 n = 3.4177 r2 = -6.685 FIG. 1 shows the present invention. 1 shows a schematic configuration based on the first embodiment of such an infrared wide-angle single lens. The diaphragm and the infrared wide-angle single lens 1 are arranged in this order from the object side to the image plane side. FIG.
(A), (b), (c) is an aberration diagram showing aberration characteristics of the first embodiment of the infrared wide-angle single lens according to the present invention. 2A shows a spherical aberration characteristic with a solid line and a sine condition with a broken line, and FIG. 2B shows an astigmatism characteristic with a sagittal image surface curve shown by a solid line and a tangential image surface curve shown by a broken line, and FIG. )
Indicates distortion characteristics, respectively. Similarly, FIG.
FIGS. 4 (b) and 4 (c) and FIGS. 4 (a), 4 (b) and 4 (c) are aberration diagrams showing the aberration characteristics of the second embodiment and the third embodiment of the infrared wide-angle single lens according to the present invention. Is.

Table 1 shows peripheral light amount ratios for each relative angle of view in the first to third embodiments of the infrared wide-angle single lens according to the present invention. As shown in (Table 1), the margin of change in the peripheral light amount ratio characteristic is about 20%, which realizes a good peripheral light amount ratio characteristic.

[0024]

[Table 1]

FIG. 5 is a schematic configuration diagram when the infrared wide-angle single lens of the above embodiment is used in the non-contact temperature measuring device 6. The non-contact temperature measuring device 6 of the present invention includes an infrared wide-angle single lens 1, a diaphragm 2, a pyroelectric infrared detector 3 arranged in an array of eight elements in the vertical direction, and intermittently shields infrared light. It is composed of a chopper 4 and a motor 5 for laterally scanning the entire unit. In such a configuration, the infrared light intermittently shielded by the chopper 4 is imaged on the pyroelectric infrared detector 3 by the infrared wide-angle single lens 1 and is one-dimensionally divided into eight areas in the vertical direction. An infrared image is detected. And the motor 5
The two-dimensional infrared image is detected by scanning in the horizontal direction. Further, the human body position can be detected from the measured temperature distribution of each area.

As described above, according to the present embodiment, by using the infrared wide-angle single lens and the pyroelectric infrared detector of the present invention, it is possible to measure the temperature distribution of the object to be measured, which is small in size. Thus, a low-cost non-contact temperature measuring device can be realized.

FIG. 6 shows a schematic configuration of an air conditioner 12 using the non-contact temperature measuring device 6 of the present invention. Air conditioner 1
Reference numeral 2 denotes a non-contact temperature measuring device 6 of the present invention, a data forming part 7 for forming data of temperature distribution of each region from a signal output from the non-contact temperature measuring device 6, and an air conditioner based on the data obtained from the data forming part 7. It is composed of a control signal forming unit 8 for forming a control signal, an air conditioning control unit 9 for controlling wind power of the air conditioner, a wind direction, a temperature of exhaust air, and the like, and an air conditioner housing 10 having a blower port 11. The air conditioner 12 is a non-contact temperature measuring device 6 using an infrared wide-angle single lens according to the present invention.
By using, the air conditioner capable of detecting the human body position and measuring the temperature distribution of each area in the room and performing the optimum air conditioning control using the measurement result can be realized in a small size and at low cost.

[0028]

As is apparent from the above description,
By configuring the infrared wide-angle single lens of the present invention as described above, although the single lens is a single lens, the peripheral light amount ratio changes while realizing good imaging characteristics in the entire imaging region with a half field angle of 60 deg. It is possible to provide an infrared wide-angle single lens satisfying excellent performance with a width of about 20%.

Particularly, since the peripheral light amount ratio is substantially uniform,
It is possible to focus infrared rays on a plurality of infrared detection pixels arranged in a one-dimensional array or two-dimensionally forming an infrared detector, with the same distribution as the temperature distribution of the measurement target.

As a result, it is not necessary to correct the output of the infrared detector by the peripheral light amount ratio characteristic of the optical system, and a high S / N ratio can be obtained even in the peripheral portion of the image.

Further, because of the good image forming characteristics from the center of the image forming to the peripheral portion and the uniform peripheral light amount ratio characteristic, some decentering is required for the optical axis alignment of the infrared wide-angle single lens and the infrared detector according to the present invention. Even if the error occurs, an error is unlikely to occur in the measurement, and the assembly and adjustment are easy.

Further, by using the infrared wide-angle single lens and the infrared detector of the present invention, a compact, low-cost non-contact temperature measuring device can be realized.

Further, by using the non-contact temperature measuring device of the present invention, it is possible to detect the human body position and measure the temperature distribution in each area of the room, and use the measurement result to perform optimum air conditioning control. The device can be realized in a small size and at low cost.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram based on a first embodiment of an infrared wide-angle single lens of the present invention.

2 (a), (b), and (c) are aberration diagrams showing aberration characteristics of the first embodiment, (a) showing spherical aberration characteristics and sine condition characteristics, and (b) respectively. Is the astigmatism characteristic,
(C) shows distortion aberration characteristics, respectively.

FIG. 3 is an aberration diagram showing aberration characteristics of the second embodiment.

FIG. 4 is an aberration diagram showing aberration characteristics of the third embodiment.

FIG. 5 is a schematic configuration diagram of a non-contact temperature measuring device using an infrared wide-angle single lens of the present invention.

FIG. 6 is a schematic configuration diagram of an air conditioner using the non-contact temperature measuring device of the present invention.

FIG. 7 is a schematic configuration diagram of a conventional non-contact temperature measuring device.

[Explanation of symbols]

 1 ... Infrared wide-angle single lens 2 ... Aperture 3 ... Pyroelectric infrared detector 4 ... Chopper 5 ... Motor 6 ... Non-contact temperature measuring device

Claims (5)

[Claims] 1. A biconvex lens having an aperture on the object side, wherein d0 is the surface distance from the aperture to the first lens surface, d1 is the lens center thickness, bf is the back focus, and n is the wavelength 10.
When the focal length is f, which is the refractive index of the glass material at μm, (1) 0.15 <d0 / f <0.3 (2) 0.45 <(d0 + d1 / n) / f <0.65 (3) 1.3 <(d0 + d1 / n + bf) / f <1.
An infrared wide-angle single lens which satisfies the following conditions (1), (2), and (3). 2. An ideal image height at a relative field angle of 0.7 when the half field angle is 60 deg and Dist 0.7 is a maximum field angle of 1, y7 is a principal ray image height of a real ray, and Dist1.0.
Is the ideal image height at the maximum angle of view and y1 is the principal ray image height of the real light ray, and the distortion aberration is defined by the following equation, Dist0.7 = (y7−y07) / y07 Dist1. 0 = (y1-y01) / y01 (4) -0.25 <Dist0.7 <-0.2 (5) -0.5 <Dist1.0 <-0.45 Conditions (4), (5) The infrared wide-angle single lens according to claim 1, wherein 3. The infrared wide-angle single lens according to claim 1, wherein the condition (6) of 0.7 <bf / f <1 is satisfied when bf is a back focus. 4. A non-contact temperature measuring device comprising the infrared wide-angle single lens according to claim 1 and an infrared detector for detecting light input through the lens. 5. An air conditioner comprising the non-contact temperature measuring device according to claim 4 and control means for controlling air conditioning based on an output from the device.