JPS61128639A - Photodetector - Google Patents

Abstract

PURPOSE:To obtain a wide angle of photodetection region even with a single photodetector by providing a condenser lens forming a light passing gap between the peripheral of an aperture and an aperture inner wall to the aperture of a cylindrical reflecting plate reflecting and introducing the incident light toward inside. CONSTITUTION:A photodetector 1 and a light transmitter 2 have metal-made cylindrical reflection plates 11, 21 spread forwardly respectively and the aperture faces a full face panel 31. The reflecting plate 11 of the photodetector 1 is spread by a prescribed angle theta and the front aperture 111 is provided with a Fresnel lens 12 as the condenser lens. The lens 12 is a disc smaller in diameter than the diameter of the aperture 111 and provided in coincidence with the center of the aperture 111 and a light passing gap 12a is formed between the peripheral and the aperture inner wall 11a. The photodetector 13 is provided toward the reflecting plate 11 at the rear aperture of the reflection plate 11 at the focus of the lens 12. When the light incident on the photodetector 1 is in parallel with a central axis of the reflecting plate 11, the light is received by the element 13, and the incident light incident at an angle over alpha on the center axis is reversed on the reflecting plate 11 and not received by the element 13, but the light passing through the gap 12a is received by the element 13.

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は車両間での光通信に使用して好適な受光器に関
するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a light receiver suitable for use in optical communication between vehicles.

〔従来の技術〕[Conventional technology]

光通信に使用する受光器において、受光素子の前方に筒
状の集光用反射板を設けるとともに、該反射板の光入射
開口に開口全面を覆う集光レンズを設けて、遠方より至
る光を小面積の受光素子に効果的に入射せしめるように
したものがある。In a light receiver used for optical communication, a cylindrical light-collecting reflector is provided in front of the light-receiving element, and a light-condensing lens that covers the entire aperture is provided in the light input aperture of the reflector to collect light from a distance. There is one that allows the light to be effectively incident on a small-area light-receiving element.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

かかる受光器は一般に鋭い受光指向性を示し、これを車
両通信に使用した場合には相手車両との相対位置がわず
かに変化しても通信が不能になるという問題点がある。Such a light receiver generally exhibits sharp light reception directivity, and when used for vehicle communication, there is a problem that communication becomes impossible even if the relative position with respect to the other vehicle changes slightly.

そこで、複数個の受光素子を並設して受光範囲を広くす
ることが考えられるが、受光素子を多数並列に接続する
と各素子の有する静電容量により信号応答性が低下し、
また各素子の境界で受光の死角が生じるという問題があ
る。Therefore, it may be possible to widen the light receiving range by arranging multiple light receiving elements in parallel, but if a large number of light receiving elements are connected in parallel, the signal response will decrease due to the capacitance of each element.
Furthermore, there is a problem in that a blind spot for light reception occurs at the boundary between each element.

本発明は上記問題点に鑑み、単一の受光素子を使用して
、しかも広角度の受光領域を得ることが可能な受光器を
提供することを目的とする。SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a light receiver that uses a single light-receiving element and can obtain a wide-angle light-receiving area.

〔問題点を解決するための手段〕[Means for solving problems]

本発明の受光器１を第１図に示す。受光器１は、前方に
向けて拡開せしめた開口より光を入射せしめるとともに
内壁を光反射面１１ａとなして上記入射光を内方へ反射
導入するようになした筒状反射板１１と、該反射板１１
の開口に設は該同口径よりも小径となしてその外周と上
記開口内壁間に光通過間隔１２ａを形成した集光レンズ
１２と、上記反射板１１内の後端部において、上記集光
レンズ１２の焦点に設けた受光素子１３とを頁面してい
る。A light receiver 1 of the present invention is shown in FIG. The light receiver 1 includes a cylindrical reflecting plate 11 that allows light to enter through an opening that is widened toward the front, and has an inner wall that serves as a light reflecting surface 11a to reflect and introduce the incident light inward. The reflecting plate 11
A condenser lens 12 is provided in the aperture, and the condenser lens 12 has a smaller diameter than the aperture, and has a light passage interval 12a between its outer periphery and the inner wall of the aperture. The page shows the light receiving element 13 provided at the focal point of 12.

〔作用、効果〕[action, effect]

反射板１１の中心軸に対して角度αを成して入射する光
りは、上記角度αが一定値を越えると、第３図（２）に
示す如く集光レンズ１２を通過した部分は途中で入射方
向が逆転して受光素子１３には至らなくなる。しかして
、この場合には間隔１２ａを通過した光が反射板１１内
で反射されて上記受光素子１３に入射する。When the angle α exceeds a certain value, the light that enters at an angle α with respect to the central axis of the reflector 11 will have a part that passes through the condensing lens 12, as shown in FIG. 3 (2). The direction of incidence is reversed and the light does not reach the light receiving element 13. In this case, the light that has passed through the interval 12a is reflected within the reflection plate 11 and enters the light receiving element 13.

かくの如くして、反射板１１の開口全面に集光レンズを
設けた従来装置に比して、広角度に受光することができ
、特に彼我の相対位置が変動する車両間の通信に使用し
て大きな効果を元厚する。In this way, compared to the conventional device in which a condensing lens is provided over the entire aperture of the reflector plate 11, light can be received at a wider angle, and this device is particularly useful for communication between vehicles where the relative positions of the two vehicles change. and enhance the effect.

また、単一の受光素子を使用しているから、受光の死角
を生じることはなく、かつ応答も速い。Furthermore, since a single light-receiving element is used, there is no blind spot for light reception, and the response is fast.

〔実施例１〕 第１図には本発明の受光器１を内設した送受光器Ｈの全
体断面図を示し、第２図にはその正面図を示す。なお、
第１図において、２は送光器である。受光器１および送
光器２はいずれも前方に向けて拡開する金属製の円筒反
射板１１．２１を有し、これらは長方形状の全面パネル
３１に開口している（図中１１１，２１１）。上記パネ
ル３１はその全面にこれを覆うように設けたアクリル製
カバー板３２とともに、これらの外周に沿って設けた枠
体３３にネジ固定（図示略）される。なお、上記各反射
板１１．２１の内壁１１ａ、２１ａはクロムメッキを施
こして反射面としである。[Embodiment 1] FIG. 1 shows an overall sectional view of a light transmitter/receiver H in which a light receiver 1 of the present invention is installed, and FIG. 2 shows a front view thereof. In addition,
In FIG. 1, 2 is a light transmitter. Both the light receiver 1 and the light transmitter 2 have metal cylindrical reflectors 11 and 21 that expand toward the front, and these are opened in a rectangular front panel 31 (111 and 211 in the figure). ). The panel 31 is fixed with screws (not shown) to a frame 33 provided along the outer periphery thereof, together with an acrylic cover plate 32 provided to cover the entire surface thereof. Note that the inner walls 11a and 21a of each of the reflecting plates 11.21 are chromium plated to serve as reflective surfaces.

上記送光器２は公知の構造を有し、その反射板２１の前
端開口２１１にはこれと同径の送光用フレネルレンズ２
２が覆着しである。該フレネルレンズ２２は径方向対称
位置に形成した突起部２２１（第２図）にて前面パネル
３１にネジ止めされている。上記反射板２１内にはフレ
ネルレンズ２２の焦点に発光素子２３が配設してあり、
これは反射板２１の後端開口に覆着したプリント基板２
４に固定しである。プリント基板２４上には公知の回路
構成を有する送信回路部２５が設けである。The light transmitter 2 has a known structure, and a light transmitting Fresnel lens 2 having the same diameter as the front end opening 211 of the reflecting plate 21 is provided.
2 is covered. The Fresnel lens 22 is screwed to the front panel 31 at protrusions 221 (FIG. 2) formed at radially symmetrical positions. A light emitting element 23 is disposed in the reflector 21 at the focal point of the Fresnel lens 22,
This is the printed circuit board 2 covered in the rear end opening of the reflector 21.
It is fixed at 4. A transmitting circuit section 25 having a known circuit configuration is provided on the printed circuit board 24.

さて、受光器１の反射板１１は一定角度θで拡開せしめ
てあり、その前端間口１１１には集光レンズとしての受
光用フレネルレンズ１２が設けである。該フレネルレン
ズ１２は開口１１１の径よりも小径の円形として上記間
口１１１に中心を一致せしめ°Ｃ設けてあって、その外
周と間口内壁１１ａとの間には光通過間隔１２ａが形成
されている。上記フレネルレンズ１２の焦点に位置する
反射板１１の後端開口には反射板１１内に向けて受光素
子１３が設けてあり、これは上記後端開口に覆着したプ
リント基板１４に固定しである。プリント基板１４上に
は公知の回路構成を有する受信回路部１５が設けである
。Now, the reflecting plate 11 of the light receiver 1 is expanded at a constant angle θ, and a Fresnel lens 12 for receiving light as a condensing lens is provided at the front end opening 111 of the reflecting plate 11. The Fresnel lens 12 has a circular shape with a diameter smaller than the diameter of the opening 111 and its center coincides with the opening 111, and a light passage interval 12a is formed between its outer periphery and the inner wall 11a of the opening. . A light-receiving element 13 is provided at the rear end opening of the reflector 11 located at the focal point of the Fresnel lens 12 and faces into the reflector 11, and this is fixed to a printed circuit board 14 covered with the rear end opening. be. A receiving circuit section 15 having a known circuit configuration is provided on the printed circuit board 14.

なお、反射板１１内に入射した光を効率的に受光素子１
３に反射導入せしめるには上記拡開角度Ｑは小さいほう
が良いが、受光素子１３の受光面は一般に１０ｍ１１１
四方と小さいから、ある程度広範囲の受光をなすには角
度θはそれ程小さくできない。そこで、本実施例では角
度θを４０度とした。Note that the light incident on the reflection plate 11 is efficiently transferred to the light receiving element 1.
3, it is better to have a small expansion angle Q, but the light receiving surface of the light receiving element 13 is generally 10 m111.
Since it is small (four sides), the angle θ cannot be made so small in order to receive light over a certain wide range. Therefore, in this embodiment, the angle θ was set to 40 degrees.

上記受晃器１および送光器２はカバー板３４にて覆って
あり、これらを一体に設けた送受光器Ｈは上記カバー板
３４に設けた閃絡の取付金具により車両の前部および後
部にそれぞれ設置される。The above-mentioned receiver 1 and transmitter 2 are covered with a cover plate 34, and the transmitter-receiver H, which is provided integrally with them, is attached to the front and rear parts of the vehicle by means of flashing mounting brackets provided on the cover plate 34. will be installed respectively.

しかして、同一構造の送受光器Ｈを装備する前方車両あ
るいは後方車両の送光器より発せられた信号光は上記受
光器１に入力する。Thus, the signal light emitted from the light transmitter of the front vehicle or the rear vehicle equipped with the light transmitter/receiver H having the same structure is input to the light receiver 1.

受光器１に入射する光の径路を第３図に示す。The path of light incident on the light receiver 1 is shown in FIG.

反射板１１の中心軸に平行に入射した光りは、第３図（
１）に示す如く、フレネルレンズ１２により直接受光索
子１３に入射せしめられるとともに、間隔１２ａを通過
したその一部は反射板１１の反射面１１ａにて反射され
て受光素子１３に入力する。The light incident parallel to the central axis of the reflector 11 is shown in Figure 3 (
As shown in 1), the Fresnel lens 12 causes the light to enter the light receiving element 13 directly, and a portion of the light that has passed through the interval 12a is reflected by the reflective surface 11a of the reflecting plate 11 and is input to the light receiving element 13.

さて、入射光りと反射板１１の中心軸とのなＪ角度αが
ある直よりも大きくなると、第３図（２）に示す如く、
フレネルレンズ１２により集光された光しは反射面１１
ａにて反射される間に入射方向が逆転して受光素子１３
に到達しなくなる。すなわち、反射板１１の開口１１１
全面にフレネルレンズ１２を設けた従来の受光器ではこ
の角度で受光素子１３への入光は無くなる。ここにおい
て、本発明の受光器では、図示の如く、間隔１２ａを通
過した光りが反射面１１ａを経て受光素子１３へ入射す
る。Now, when the angle J between the incident light and the central axis of the reflecting plate 11 becomes larger than a certain angle, as shown in FIG. 3 (2),
The light focused by the Fresnel lens 12 is reflected by the reflective surface 11
While being reflected at a, the direction of incidence is reversed and the light receiving element 13
will no longer reach. That is, the opening 111 of the reflecting plate 11
In a conventional light receiver having a Fresnel lens 12 on the entire surface, no light enters the light receiving element 13 at this angle. Here, in the light receiver of the present invention, as shown in the figure, light passing through the interval 12a enters the light receiving element 13 via the reflective surface 11a.

第４図には、反射板１１の開口１１１を全てフレネルレ
ンズで覆った従来の受光器と光通過間隔１２ａを設けた
本発明の受光器について、一定光度かつ一定距離の光源
からの入射光角度αを変化せしめた場合の受光ｍ変化を
示す。図中線Ｘは本発明を示し、線ｙは従来例を示す。FIG. 4 shows the incident light angle from a light source with a constant luminous intensity and a constant distance for a conventional light receiver in which the aperture 111 of the reflector plate 11 is entirely covered with a Fresnel lens and a light receiver of the present invention in which a light passage interval 12a is provided. It shows the change in received light m when α is changed. Line X in the figure shows the present invention, and line y shows the conventional example.

なお、この１９合の本発明の受光器は開口径を６０ＩＩ
ＩＩ１１とし、レンズ径を４Ｑｍｍとした。In addition, the aperture diameter of this 19-coin optical receiver of the present invention is 60II.
II11, and the lens diameter was 4Qmm.

図示の如く、従来の受光器では入射光角度αが１５度程
度で受光量は急激に低下している。これに対して、本発
明においては、上記角度αが１０度以内では集光レンズ
を設けない部分の集光効率の悪化による若干の受光量低
下はあるものの、角度αが２０度程度まで大きくなって
も比較的大きな受光量を得ることができる。As shown in the figure, in the conventional light receiver, the amount of light received decreases rapidly when the incident light angle α is about 15 degrees. On the other hand, in the present invention, when the angle α is less than 10 degrees, there is a slight decrease in the amount of light received due to deterioration of the light collection efficiency in the part where the condenser lens is not provided, but when the angle α increases to about 20 degrees, However, a relatively large amount of light can be obtained.

発明者らの実験によれば、角度αが小さい領域における
集光効率をそれ程悪化させることなく広い受光角度を得
るには、反射板の開口径と集光レンズ径の比は２／３と
するのが良い。According to experiments conducted by the inventors, in order to obtain a wide acceptance angle without significantly deteriorating the light collection efficiency in a region where the angle α is small, the ratio of the aperture diameter of the reflector to the diameter of the condensing lens should be 2/3. It's good.

以上の如く、本発明の受光器は鋭い受光指向性を保持し
つつ、比較的近距離において広角度な受光領域を有する
もので、間隔が離れている場合には彼我の相対位置変化
が比較的小さく、間隔が接近した場合に大きな相対位置
変化を生じる、相前後して走行する車両間の通信に使用
して特に好適なものである。As described above, the light receiver of the present invention has a wide angle light receiving area at a relatively short distance while maintaining sharp light receiving directivity, and when the distance is far apart, the relative position change between the two is comparatively large. It is particularly suitable for use in communications between vehicles running one after the other, which have a small distance and cause large changes in relative position when they are close together.

本発明の受光器は中−の受光素子を使用しているから、
入用光に対する死角はなくかつ応答性も良い。Since the light receiver of the present invention uses a medium-sized light receiving element,
There are no blind spots to the required light and the responsiveness is good.

〔実施例２〕 第５図において、反射板１１はその１１２端部１１２の
拡開角度を小さくしである。このような構造とすれば、
図示の経路で入射した光りの方向が反射途中で逆転する
ことはなく、効率的に受光素子１３へ入射せしめられる
。[Embodiment 2] In FIG. 5, the reflection plate 11 has its 112 end 112 expanded at a small angle. With a structure like this,
The direction of the light incident on the illustrated path is not reversed during reflection, and is efficiently made incident on the light receiving element 13.

〔実施例３〕 第６図において、反射板１１はその前端部１１３の拡開
角度を大きくしである。かかる構造によれば、より広い
角度範囲の光りを入射せしめることができる。[Embodiment 3] In FIG. 6, the reflection plate 11 has its front end 113 expanded at a large angle. According to such a structure, it is possible to allow light to be incident in a wider angular range.

なお、上記反射板１１は後端部Ｊ：り前端部に向けて次
第に拡開角度が大きくなるラッパ形状とするとさらに効
果的に光を捕集することができる。Note that if the reflector plate 11 is formed into a trumpet shape in which the expansion angle gradually increases from the rear end J to the front end, light can be collected more effectively.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の受光器を具備する送受光器の全体断面
図、第２図はその正面図、第３図は受光器への入射光経
路を示す受光器の概略断面図、第４図は本発明の受光器
と従来の受光器について、入射光角度による受光量変化
を比較した図、第５図、第６図はそれぞれ本発明の第２
および第３の実施例を示す受光器の全体断面図である。 １・・・・・・受光器 １１・・・・・・反射板 １１ａ・・・・・・反射面 １１２・・・・・・後端部 １１３・・・・・・前端部 １２・・・・・・集光レンズ １２ａ・・・・・・光通過間隔 １３・・・・・・受光素子 第１図 第２図FIG. 1 is an overall sectional view of a light transmitter/receiver equipped with the light receiver of the present invention, FIG. 2 is a front view thereof, FIG. 3 is a schematic sectional view of the light receiver showing the path of incident light to the light receiver, and FIG. The figure shows a comparison of changes in the amount of received light depending on the angle of incident light between the light receiver of the present invention and a conventional light receiver.
and FIG. 7 is an overall cross-sectional view of a light receiver showing a third embodiment. 1... Light receiver 11... Reflection plate 11a... Reflection surface 112... Rear end portion 113... Front end portion 12... ... Condensing lens 12a ... Light passing interval 13 ... Light receiving element Fig. 1 Fig. 2

Claims (4)

【特許請求の範囲】[Claims] （１）前方に向けて拡開せしめた開口より光を入射せし
めるとともに内壁を光反射面となして上記入射光を内方
へ反射導入するようになした筒状反射板と、上記反射板
の開口に設け該開口径よりも小径となしてその外周と上
記開口内壁間に光通過間隔を形成した集光レンズと、上
記反射板内の後端部において、上記集光レンズの焦点に
設けた受光素子とを具備する受光器。(1) A cylindrical reflector that allows light to enter through an opening that expands toward the front and that uses an inner wall as a light reflecting surface to reflect and introduce the incident light inward; a condenser lens provided in the aperture and having a smaller diameter than the aperture diameter to form a light passage interval between the outer periphery and the inner wall of the aperture; A light receiver comprising a light receiving element. （２）上記反射板はその前端部において他の部分よりも
拡開角度を大きくなした特許請求の範囲第１項記載の受
光器。(2) The light receiver according to claim 1, wherein the front end of the reflecting plate has a larger expansion angle than other parts. （３）上記反射板はその後端部において他の部分よりも
拡開角度を小さくなした特許請求の範囲第１項記載の受
光器(3) The light receiver according to claim 1, wherein the reflecting plate has a smaller expansion angle at its rear end than at other parts. （４）上記開口径と集光レンズ径の比の値を２／３に設
定した特許請求の範囲第１項記載の受光器。(4) The light receiver according to claim 1, wherein the ratio of the aperture diameter to the condensing lens diameter is set to 2/3.