JPH0734041B2 - Condensing lens for infrared detector - Google Patents
Condensing lens for infrared detectorInfo
- Publication number
- JPH0734041B2 JPH0734041B2 JP1326372A JP32637289A JPH0734041B2 JP H0734041 B2 JPH0734041 B2 JP H0734041B2 JP 1326372 A JP1326372 A JP 1326372A JP 32637289 A JP32637289 A JP 32637289A JP H0734041 B2 JPH0734041 B2 JP H0734041B2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- plane
- hyperboloid
- angle
- condenser lens
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000001514 detection method Methods 0.000 description 13
- 230000004075 alteration Effects 0.000 description 10
- 230000003287 optical effect Effects 0.000 description 6
- 230000007423 decrease Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
- G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
- G02B19/0009—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having refractive surfaces only
- G02B19/0014—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having refractive surfaces only at least one surface having optical power
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
- G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
- G02B19/009—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with infrared radiation
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Description
本発明は赤外線式検知装置、殊に所定検知領域から発せ
られる赤外線を受光検出することによって人体の有無を
検知する受動型検知装置における集光レンズに関するも
のである。The present invention relates to an infrared detection device, and more particularly to a condenser lens in a passive detection device that detects the presence or absence of a human body by receiving and detecting infrared rays emitted from a predetermined detection area.
赤外線式検知装置では、一般に集光レンズの焦点面全面
に赤外線検知素子を配置するのではなく、集光レンズの
焦点位置に赤外線検知素子を配設することから、赤外線
検知素子によって検出される赤外線は集光レンズの光軸
と平行に入射するものだけであり、光軸に対して角度を
もった斜め入射光は焦点位置に集光しないために、検知
領域を広げるには、異なる方向に光軸を備える複数の集
光レンズを組み合わせることになる。この時、各集光レ
ンズとして、その焦点位置が一致するようにした場合に
は、レンズ全体が半球状となり、曲率が小さくなって製
作が困難となることから、通常、集光レンズにある方向
から斜め入射した光線が赤外線検知素子が配された位置
に焦点を結ぶようにすることで、レンズ全体の曲率を大
きくとることができるようにしている。一例を第７図に
示す。各集光レンズ１はフレネルレンズとして形成され
て、これらが組み合わされている。In an infrared type detection device, generally, the infrared detecting element is not arranged on the entire focal plane of the condenser lens, but the infrared detecting element is arranged at the focal position of the condenser lens. Is incident only parallel to the optical axis of the condenser lens, and obliquely incident light with an angle with respect to the optical axis does not focus at the focal position. A plurality of condenser lenses with axes will be combined. At this time, if the focal positions of the condenser lenses are made to coincide with each other, the entire lens becomes hemispherical, the curvature becomes small, and the manufacturing becomes difficult. By making the light beam obliquely incident on the lens focus on the position where the infrared detecting element is arranged, the curvature of the entire lens can be made large. An example is shown in FIG. Each condenser lens 1 is formed as a Fresnel lens, and these are combined.
ところが、上述のように光軸に対して角度をもった斜め
入射光を利用する場合には、集光レンズがもつ収差によ
る「ぼけ」の問題点がつきまとう。これはフレネルレン
ズを用いた場合には、特に顕著となってしまうものであ
り、そして「ぼけ」によって検知ビームが所定の大きさ
以上に広がった場合、赤外線検出素子に入射する赤外線
量が低下するために、感度の低下を招くほか、耐環境性
及び耐外乱性の向上のために赤外線検知素子として２個
のエレメントによる差動出力を用いるツイン素子が使用
されている場合には、２個のエレメントにより生じる２
検知ビームに重なり合う部分で出力が打ち消し合ってし
まうために、感度の低下が更に顕著にあらわれることに
なる。 この点を嫌って集光用光学系として放物面ミラーを組み
合わせた多分割ミラーを用いたものがあるが、この場
合、「ぼけ」による影響は小さく、また反射率が通常90
％以上であるために効率良く集光することができるもの
の、光学系が大きくなってしまうという問題を有してい
る。 本発明はこのような点に鑑み為されたものであり、その
目的とするところは小型で集光効率に優れた赤外線式検
知装置用集光レンズを提供するにある。However, as described above, when the oblique incident light having an angle with respect to the optical axis is used, there is a problem of “blur” due to the aberration of the condenser lens. This is particularly noticeable when a Fresnel lens is used, and when the detection beam spreads beyond a predetermined size due to "blurring", the amount of infrared light that enters the infrared detection element decreases. Therefore, in addition to lowering the sensitivity, if a twin element using a differential output by two elements is used as an infrared detection element for improving the environmental resistance and the disturbance resistance, two elements are used. 2 caused by the element
Since the outputs cancel each other at the portion where the detection beam overlaps, the decrease in sensitivity becomes more remarkable. Some people dislike this point and use a multi-division mirror that combines a parabolic mirror as the condensing optical system, but in this case, the effect of "blur" is small and the reflectance is usually 90%.
%, The light can be condensed efficiently, but there is a problem that the optical system becomes large. The present invention has been made in view of the above points, and an object of the present invention is to provide a compact condenser lens for an infrared detection device, which is excellent in condenser efficiency.
しかして本発明は、第一面が平面、第二面が双曲面であ
り、第二面の双曲面の回転軸が第一面の平面に対して斜
交していることに特徴を有している。 ［作用］ 本発明によれば、双曲面の回転軸と平行とがなす角度に
応じて、焦点に無収差で集光する平行光と平面の法線方
向との間に角度を持たせることができるために、必要と
する方向にレンズを向けなくとも、この方向からの赤外
線の集光を効率よく行うことができる。 すなわち、第６図は第一面が平面10、第二面が双曲面20
として形成されているとともに、双曲面20の回転軸Ｃが
第一面の平面10の法線Ｈ方向と一致している通常の無収
差単レンズであり、光軸（この場合、双曲面の回転軸及
び平面の法線と一致）と平行な入射光は無収差で焦点Ｆ
に集光される。このような双曲面20を有する集光レンズ
１において、第５図に示すように、第一面の平面10の法
線Ｈと第二面の双曲面20の回転軸Ｃとが角度θをなすよ
うに第一面の平面10を傾けると、回転軸Ｃに対してある
角度δで入射して集光レンズ１内で双曲面の回転軸Ｃと
平行となる光線が焦点Ｆに無収差で集光することにな
る。尚、ここにおける角度δは、集光レンズ１の屈折率
をＮとする時、スネルの法則 sin（θ＋δ）＝Nsinθ を満足する角度である。 第１図は第一面の平面10を基準に考えた場合を示してお
り、第一面の平面10の法線Ｈに対して角度（θ＋δ）で
入射する平行光が無収差で焦点Ｆに集光する。 角度θを大きくすれば、焦点Ｆに無収差で集光する平行
光が第一面の平面10の法線Ｈとなす角度（θ＋δ）も大
きくなるものであり、そしてある検知領域を設定するに
あたり、第一面の平面10をその検知領域に向けなくと
も、検知領域から出る赤外線を集光レンズ１は無収差で
焦点Ｆ位置に置かれる赤外線検知素子に集光させること
ができるものである。 ［実施例］ 以下本発明を図示の実施例に基づいて詳述すると、第２
図は第一面の平面10の法線Ｈと、第二面の双曲面20の回
転軸Ｃとがなす角度θが24.842°、屈折率が1.53、焦点
距離を14.5mm、最大肉厚0.8mmの集光レンズ１を示して
いる。この場合、焦点Ｆに無収差で集光する平行光が第
一面の平面10の法線Ｈとなす角度は40°となる。 ところで、この種のレンズ素材として一般に用いられる
ポリエチレンは、安価で加工性が良いものの、厚みが増
えると吸収のために透過率が低くなるので、集光レンズ
１の厚みをできるだけ薄くする必要があるが、これは第
３図に示すように、フレネルレンズとすることで、レン
ズ面積を小さくすることなく、薄型化を図ることができ
る。 第二面の双曲面20が中央部の第１輪体21とこれを取り囲
む第２輪体22、第２輪体22を更に取り囲む第３輪体23か
らなるこの集光レンズ１では、各輪体21,22,23における
回転軸が同じで且つ回転軸との交点における曲率半径が
少しずつ異なっている各双曲面を、夫々最大肉厚が0.8m
m、最小肉厚が0.3mmとなるようにして、第一面の平面10
の法線Ｈ方向に重ね合わせている。このために、各輪体
21,22,23は楕円形となっている。 そして、第４図は、第一面の平面10の法線Ｈと、焦点Ｆ
に無収差で集光する平行光線とのなす角度がα１である
４つのフレネルタイプの集光レンズ１を環状に並べると
ともに、これらの外周に上記角度がα２（α２＞α１）
である８つのフレネルタイプの集光レンズ１を環状に並
べてフラット型多分割レンズを構成した場合を示してい
る。尚、各集光レンズ１の焦点Ｆが同一位置であり且つ
この位置に赤外線検知素子３を配していることはもちろ
んである。Therefore, the present invention is characterized in that the first surface is a flat surface, the second surface is a hyperboloid, and the rotation axis of the hyperbolic surface of the second surface is oblique to the plane of the first surface. ing. [Operation] According to the present invention, depending on the angle formed by the axis of rotation of the hyperboloid and the parallel direction, an angle can be provided between the parallel light that is focused on the focal point without aberration and the normal direction of the plane. Therefore, it is possible to efficiently collect infrared rays from this direction without pointing the lens in the required direction. That is, in FIG. 6, the first surface is the plane 10 and the second surface is the hyperboloid 20.
Is a normal aplanatic single lens in which the rotation axis C of the hyperboloid 20 coincides with the normal H direction of the plane 10 of the first surface, and the optical axis (in this case, rotation of the hyperboloid Incident light parallel to the axis and the normal to the plane) is a focus F without aberration.
Is focused on. In the condenser lens 1 having such a hyperboloid 20, as shown in FIG. 5, the normal H of the plane 10 of the first surface and the rotation axis C of the hyperboloid 20 of the second surface form an angle θ. When the plane 10 of the first surface is tilted as described above, a ray that is incident on the rotation axis C at an angle δ and is parallel to the rotation axis C of the hyperboloid inside the condenser lens 1 is focused on the focus F without aberration. It will shine. Note that the angle δ here is an angle that satisfies Snell's law sin (θ + δ) = N sin θ, where N is the refractive index of the condenser lens 1. FIG. 1 shows a case where the plane 10 of the first surface is considered as a reference, and collimated light incident at an angle (θ + δ) with respect to the normal line H of the plane 10 of the first surface is focused on the focus F without aberration. Collect light. When the angle θ is increased, the angle (θ + δ) formed by the parallel light, which is focused on the focal point F without aberration, with the normal line H of the plane 10 of the first surface is also increased, and when setting a certain detection area. Even if the plane 10 of the first surface is not directed to the detection area, the condenser lens 1 can focus the infrared rays emitted from the detection area to the infrared detection element placed at the focal point F without aberration. [Embodiment] The present invention will be described in detail below with reference to the illustrated embodiment.
The figure shows that the angle H between the normal H of the plane 10 of the first surface and the rotation axis C of the hyperboloid 20 of the second surface is 24.842 °, the refractive index is 1.53, the focal length is 14.5 mm, and the maximum wall thickness is 0.8 mm. The condensing lens 1 of FIG. In this case, the angle formed by the parallel light, which is focused on the focal point F without aberration, with the normal line H of the plane 10 of the first surface is 40 °. By the way, polyethylene, which is generally used as a lens material of this kind, is inexpensive and has good workability, but since the transmittance decreases due to absorption when the thickness increases, it is necessary to make the thickness of the condenser lens 1 as thin as possible. However, as shown in FIG. 3, by using a Fresnel lens, it is possible to reduce the thickness without reducing the lens area. In this condenser lens 1 in which the hyperboloid 20 of the second surface is composed of the first wheel body 21 in the central part, the second wheel body 22 surrounding the first wheel body 21, and the third wheel body 23 further surrounding the second wheel body 22, The maximum wall thickness of each hyperbolic surface is 0.8 m for each of the hyperboloids with the same axis of rotation in the bodies 21, 22 and 23 and with a slightly different radius of curvature at the intersection with the axis of rotation.
m, with a minimum wall thickness of 0.3 mm
Are overlapped in the normal line H direction. For this, each wheel
21,22,23 are elliptical. And FIG. 4 shows the normal H of the plane 10 of the first surface and the focus F.
In addition to arranging four Fresnel-type condensing lenses 1 having an angle of α 1 with a parallel light beam that is condensed with no aberration, the above-mentioned angles are α 2 (α 2 > α 1 ) on their outer circumferences.
8 shows a case in which eight Fresnel type condenser lenses 1 are arranged in a ring to form a flat type multi-divided lens. Needless to say, the focus F of each condenser lens 1 is at the same position and the infrared detecting element 3 is arranged at this position.
以上のように本発明においては、双曲面の回転軸と平行
とがなす角度に応じて、焦点に無収差で集光する平行光
と平面の法線方向との間に角度を持たせることができる
ために、必要とする方向にレンズを向けなくとも、この
方向からの赤外線の集光を効率よく行うことができるも
のであり、小型で集光効率に優れたものとすることがで
きる。As described above, in the present invention, depending on the angle formed by the rotation axis of the hyperboloid and the parallel direction, an angle can be provided between the parallel light that is focused on the focus without aberration and the normal direction of the plane. Therefore, it is possible to efficiently collect infrared rays from this direction without directing the lens in the required direction, and it is possible to make the infrared light compact and have excellent light collection efficiency.
第１図は本発明に係る集光レンズの断面図、第２図は一
実施例の断面図、第３図（ａ）（ｂ）はフレネルタイプ
とした場合の正面図と断面図、第４図（ａ）（ｂ）は多
分割レンズとした場合の正面図と側面図、第５図は本発
明を説明する断面図、第６図は通常の双曲面レンズの断
面図，第７図は従来例の斜視図であって、１は集光レン
ズ、10は平面、20は双曲面、Ｈは平面の法線、Ｃは双曲
面の回転軸を示す。1 is a sectional view of a condenser lens according to the present invention, FIG. 2 is a sectional view of an embodiment, and FIGS. 3 (a) and 3 (b) are a front view and a sectional view of a Fresnel type, and FIG. Figures (a) and (b) are front and side views in the case of a multi-divided lens, FIG. 5 is a sectional view for explaining the present invention, FIG. 6 is a sectional view of an ordinary hyperboloid lens, and FIG. 1 is a perspective view of a conventional example, in which 1 is a condenser lens, 10 is a plane, 20 is a hyperboloid, H is a normal to the plane, and C is a rotation axis of the hyperboloid.
Claims (1)
二面の双曲面の回転軸が第一面の平面に対して斜交して
いることを特徴とする赤外線式検知装置用集光レンズ。1. An infrared type wherein the first surface is a flat surface, the second surface is a hyperboloid, and the rotation axis of the hyperbolic surface of the second surface is oblique to the plane of the first surface. Condensing lens for detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1326372A JPH0734041B2 (en) | 1989-12-15 | 1989-12-15 | Condensing lens for infrared detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1326372A JPH0734041B2 (en) | 1989-12-15 | 1989-12-15 | Condensing lens for infrared detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03186801A JPH03186801A (en) | 1991-08-14 |
| JPH0734041B2 true JPH0734041B2 (en) | 1995-04-12 |
Family
ID=18187065
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1326372A Expired - Lifetime JPH0734041B2 (en) | 1989-12-15 | 1989-12-15 | Condensing lens for infrared detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0734041B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5666221A (en) * | 1992-07-20 | 1997-09-09 | Hughes Electronics | Binary optic imaging system |
| SG189838A1 (en) * | 2011-03-01 | 2013-07-31 | Panasonic Corp | Collecting lens and multi-segment lens |
| KR101596316B1 (en) * | 2015-02-03 | 2016-02-22 | 몰렉스 엘엘씨 | Card tray for electronic device and tray carrier assembly using the same |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0638128B2 (en) * | 1985-10-07 | 1994-05-18 | 沖電気工業株式会社 | Optical coupling lens |
| JPH0617944B2 (en) * | 1985-10-28 | 1994-03-09 | 東京電子工業株式会社 | Television camera device for in-pipe inspection |
| JP2672492B2 (en) * | 1985-12-06 | 1997-11-05 | オムロン株式会社 | Photoelectric switch |
-
1989
- 1989-12-15 JP JP1326372A patent/JPH0734041B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03186801A (en) | 1991-08-14 |
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