JP2007150902A

JP2007150902A - Light receiving device

Info

Publication number: JP2007150902A
Application number: JP2005344569A
Authority: JP
Inventors: Hidenobu Hamada; 英伸浜田
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2005-11-29
Filing date: 2005-11-29
Publication date: 2007-06-14

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light receiving device for receiving axial deviation incident light within a wide angle range with respect to the incident light in a three-dimensional optical system. <P>SOLUTION: The light receiving device comprises a photodetector 4 separated from a light source 1 by a free space 2; and a condenser 10 which is arranged near the input end of the photodetector 4, where the opposing interval of a side surface having a reflecting function is reduced toward the photodetector 4, and which internally includes a reflection surface 7 including an optical axis 3 substantially facing the side surface within the range from an incident side surface 5 to a light emission side surface 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、例えば、光空間伝送に使用される受光デバイスに関するものである。 The present invention relates to a light receiving device used for optical space transmission, for example.

光空間伝送において送信部と受信部の光軸が合っているのが理想的であるが、現実的には、固定送信部と固定受信部のアライメント不良による静的軸ズレや、送信部と受信部の少なくとも一方が移動（可動）体である場合の動的軸ズレが存在する。軸ズレが発生すると受光レベルの低下によりＳＮ劣化、誤り率の増加による伝送レート低下、送信パワーの増加などの問題が生じる。さらに、高速応答する受光素子になるほど受光面積が小さくなるので、軸ズレの影響が顕著となる。なお、上記軸ズレは位置ズレと角度ズレの両者を含んでいる。光空間伝送の場合、自由空間伝搬中にビーム径はある程度広がっているので位置ズレよりも角度ズレが特に問題である。しかし、面積の小さな受光素子に集光するための従来のレンズなどは分散面が固定的な曲面であるために入射角の変動により集光位置が敏感に変化するので利得の劣化をもたらす。 Ideally, the optical axes of the transmitter and receiver are aligned in space optical transmission, but in reality, static axis misalignment due to improper alignment between the fixed transmitter and fixed receiver, or the transmitter and receiver. There is a dynamic axis shift when at least one of the parts is a moving (movable) body. When the axis shift occurs, problems such as SN degradation due to a decrease in received light level, a decrease in transmission rate due to an increase in error rate, and an increase in transmission power occur. Furthermore, since the light receiving area becomes smaller as the light receiving element responds at a higher speed, the influence of the axial deviation becomes remarkable. The axis deviation includes both positional deviation and angle deviation. In the case of optical space transmission, since the beam diameter is expanded to some extent during propagation in free space, the angle shift is more problematic than the position shift. However, a conventional lens or the like for condensing on a light receiving element having a small area has a fixed dispersion surface, so that the condensing position changes sensitively due to a change in incident angle, resulting in a deterioration in gain.

角度ズレした入射光を広角度で受光する方法としては、受光素子方向に断面が小さくなる円錐形状のレンズの側面に反射鏡を備えることにより、直接に受光素子に入射しない光も側面での反射を通して受光素子に入射させるものがある（例えば、特許文献１参照）。
また、特許文献１の円錐形状をラッパ形状のレンズにして許容指向角を広げ、さらに、レンズ内の屈折率を伝搬方向に大きくしてより許容指向角を広げたものもある（例えば、特許文献２参照）。 As a method of receiving the incident light with the angle deviation at a wide angle, by providing a reflecting mirror on the side surface of the conical lens whose cross section decreases in the direction of the light receiving element, the light that does not directly enter the light receiving element is also reflected on the side surface. In some cases, the light is incident on the light receiving element (see, for example, Patent Document 1).
In addition, there is a lens in which the conical shape of Patent Document 1 is changed to a trumpet-shaped lens to increase the allowable directivity angle, and the refractive index in the lens is increased in the propagation direction to further increase the allowable directivity angle (for example, Patent Document). 2).

また、結合素子に、入射側面に対して傾いた面であって、入射方向に対し所定の伝播角度範囲内で入射側面に入射した信号光を入射側面側に反射して、その入射側面と共同して信号光を入射側面との間隔が開いた方向に導く出射側面を備えたものもある（例えば、特許文献３参照）。
特開平８−６２０３９号公報（例えば、第１図）特開２００５−２１８１０２号公報（例えば、第１図）特開２０００−１１１７５４号公報（例えば、第１図） Further, the coupling element is a surface inclined with respect to the incident side surface, and reflects the signal light incident on the incident side surface within a predetermined propagation angle range with respect to the incident direction to the incident side surface, and cooperates with the incident side surface. In some cases, there is an emission side surface that guides the signal light in a direction in which the distance from the incident side surface is wide (see, for example, Patent Document 3).
JP-A-8-62039 (for example, FIG. 1) Japanese Patent Laying-Open No. 2005-218102 (for example, FIG. 1) Japanese Laid-Open Patent Publication No. 2000-111754 (for example, FIG. 1)

しかしながら、特許文献１の円錐形状および特許文献２のラッパ形状の一定屈折率の集光器の場合、入射角α（即ち、入射側面での屈折角α₁）が小さい光は側面での反射により受光素子に結合できるが、図５に示すように、入射角が大きい光（屈折角がα₁>3/2π-2θ₁−θ₂）は集光器側面での反射により入射側面側に反射され、受光素子に結合できない。尚、図５は、一般的な伝搬方向に接近する２個の反射面の多重反射による入射光の軌跡の説明図である。 However, in the case of the conical collector having the constant refractive index of the conical shape of Patent Document 1 and the trumpet shape of Patent Document 2, the light having a small incident angle α (that is, the refraction angle α ₁ on the incident side surface) is reflected by the side surface. Although it can be coupled to the light receiving element, as shown in FIG. 5, light having a large incident angle (refractive angle α ₁ > 3 / 2π-2θ ₁ −θ ₂ ) is reflected on the incident side surface by reflection on the collector side surface. And cannot be coupled to the light receiving element. FIG. 5 is an explanatory diagram of a locus of incident light due to multiple reflection of two reflecting surfaces approaching a general propagation direction.

それを改善するために、特許文献２では伝搬方向に屈折率が大きくなるように屈折率分布をつけて、集光器の側面の反射面への入射角を大きくなる、すなわち、伝搬にしたがって進行方向と光軸のなす角度が小さくなる様にすることで許容受光角を広げている。 In order to improve it, in Patent Document 2, a refractive index distribution is provided so that the refractive index increases in the propagation direction, and the incident angle to the reflecting surface on the side surface of the collector increases, that is, progresses according to propagation. The allowable light receiving angle is widened by reducing the angle between the direction and the optical axis.

しかし、集光器内に屈折率分布を形成することは技術的に困難であるだけでなく、コスト的にも非常に不利であるという課題がある。 However, it is not only technically difficult to form a refractive index distribution in the light collector, but also has a problem that it is very disadvantageous in terms of cost.

一方、特許文献３の従来の方法は、２次元的な光の伝搬には有効であるが、３次元的に入射する光に対しては効果が無いという問題がある。 On the other hand, the conventional method of Patent Document 3 is effective for propagation of two-dimensional light, but has a problem that it is not effective for light incident three-dimensionally.

本発明は、従来の装置のこの様な課題を考慮して、３次元光学系における入射光に対し、より広い角度範囲で軸ズレ入射光を受光できる受光デバイスを提供することを目的とする。 An object of the present invention is to provide a light receiving device that can receive axially shifted incident light in a wider angle range with respect to incident light in a three-dimensional optical system in consideration of such problems of conventional apparatuses.

この目的を達成するため本発明は、第１の本発明は、光源からの出射光を集光して出射する集光器と、前記集光器からの出射光を受光する受光素子とを備えた受光デバイスであって、
前記集光器は、両端に入射側面と出射側面とを有し、前記入射側面から入射した光を反射させる反射機能を有する側面の内部が前記入射側面から前記出射側面に向かうに従って実質上せまくなっており、前記集光器の内部には、前記入射側面から前記出射側面に亘る全部又は一部の範囲において前記側面と実質上対面する反射面が設けられている受光デバイスである。 In order to achieve this object, the present invention provides the first invention, comprising: a concentrator for collecting and emitting the light emitted from the light source; and a light receiving element for receiving the light emitted from the light collector. A light receiving device,
The concentrator has an incident side surface and an exit side surface at both ends, and the inside of the side surface having a reflection function for reflecting light incident from the incident side surface becomes substantially narrower as it goes from the incident side surface to the exit side surface. In the light collecting device, a reflection surface that substantially faces the side surface is provided in the whole or a part of the range from the incident side surface to the emission side surface.

又、第２の本発明は、上記反射面が前記集光器の光軸を含む上記第１の本発明の受光デバイスである。 The second aspect of the present invention is the light receiving device according to the first aspect of the present invention, wherein the reflecting surface includes the optical axis of the condenser.

又、第３の本発明は、上記反射面が複数であって、前記反射面同士の交線が存在する上記第１の本発明の受光デバイスである。 The third aspect of the present invention is the light receiving device according to the first aspect of the present invention, wherein there are a plurality of the reflecting surfaces, and there are intersecting lines between the reflecting surfaces.

又、第４の本発明は、上記複数の反射面の前記交線が、前記集光器の光軸に平行である上記第３の本発明の受光デバイスである。 The fourth aspect of the present invention is the light receiving device according to the third aspect of the present invention, wherein the intersecting lines of the plurality of reflecting surfaces are parallel to the optical axis of the condenser.

又、第５の本発明は、上記反射面が複数であって、前記反射面同士の交線が存在しない上記第１の本発明の受光デバイスである。 The fifth aspect of the present invention is the light receiving device according to the first aspect of the present invention, wherein there are a plurality of the reflecting surfaces, and no line of intersection exists between the reflecting surfaces.

又、第６の本発明は、上記集光器の光軸に対する前記反射面の傾斜の程度が、前記入射側面から前記出射側面に向かうに従って小さくなる上記第５の本発明の受光デバイスである。 A sixth aspect of the present invention is the light receiving device according to the fifth aspect of the present invention, wherein the degree of inclination of the reflecting surface with respect to the optical axis of the condenser is reduced as it goes from the incident side surface to the emission side surface.

又、第７の本発明は、上記反射面が金属面で形成されている上記第１の本発明の受光デバイスである。 The seventh aspect of the present invention is the light receiving device according to the first aspect of the present invention, wherein the reflecting surface is formed of a metal surface.

又、第８の本発明は、上記反射面がブラグ反射を起こす周期構造で形成されている上記第１の本発明の受光デバイスである。 The eighth aspect of the present invention is the light receiving device according to the first aspect of the present invention, wherein the reflecting surface is formed with a periodic structure that causes Bragg reflection.

又、第９の本発明は、上記反射面が、前記集光器と異なる屈折率を有する材料との全反射を起こす界面で形成されている上記第１の本発明の受光デバイスである。 The ninth aspect of the present invention is the light receiving device according to the first aspect of the present invention, wherein the reflecting surface is formed at an interface that causes total reflection between the light collector and a material having a different refractive index.

又、第１０の本発明は、上記集光器の前記入射側面と前記出射側面との少なくとも一方が曲面である上記第１〜９の何れかの本発明の受光デバイスである。 The tenth aspect of the present invention is the light receiving device according to any one of the first to ninth aspects, wherein at least one of the incident side surface and the emission side surface of the condenser is a curved surface.

又、第１１の本発明は、上記集光器の前記入射側面に、又は前記出射側面と前記受光素子との間に、特定の波長のみを透過するフィルターを備えた上記第１〜１０の何れかの本発明の受光デバイスである。 Further, an eleventh aspect of the present invention is any one of the first to tenth aspects, further comprising a filter that transmits only a specific wavelength on the incident side surface of the collector or between the emission side surface and the light receiving element. This is the light receiving device of the present invention.

本発明は、従来に比べて受信許容角度の大きな受光デバイスを提供できるという効果を発揮する。 The present invention exhibits an effect that it is possible to provide a light receiving device having a larger allowable reception angle than conventional ones.

以下、本発明の実施の形態を、図面を参照しながら説明する。
（実施の形態１）
図１（ａ）は、本発明に係る一実施の形態の受光デバイスであって、光軸を含む反射面を介して２個の導光部９が接するレンズ集光器１０を具備する受光デバイスの構成概要図である。尚、図１（ａ）は、受光デバイスの縦方向の断面を模式的に表した図であり、図１（ｂ）は、受光デバイスの光軸に垂直な断面から見た光線軌跡を説明するための模式図である。同図を用いて、本実施の形態の構成について説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1A is a light receiving device according to an embodiment of the present invention, and includes a lens concentrator 10 in which two light guides 9 are in contact via a reflecting surface including an optical axis. FIG. 1A is a diagram schematically illustrating a longitudinal section of the light receiving device, and FIG. 1B illustrates a ray trajectory viewed from a section perpendicular to the optical axis of the light receiving device. It is a schematic diagram for. The configuration of the present embodiment will be described with reference to FIG.

本願の実施の形態の受光デバイスは、図１（ａ）、（ｂ）に示すように、光源１から自由空間２で隔てられ、光軸３上の受光素子４と、入射側面５が曲面を有し、出射側面６が受光素子４に接し、側面の反射面８の対面する間隔が受光素子４に向かうに従って小さくなり、入射側面と出射側面を分割し光軸を含む反射面７を内部に具備するレンズ集光器１０とで構成されている。 As shown in FIGS. 1A and 1B, the light receiving device according to the embodiment of the present application is separated from the light source 1 by a free space 2, and the light receiving element 4 on the optical axis 3 and the incident side surface 5 have curved surfaces. The exit side surface 6 is in contact with the light receiving element 4, and the distance between the side reflecting surfaces 8 facing the surface decreases toward the light receiving element 4. The incident side surface and the exit side surface are divided to include the reflecting surface 7 including the optical axis inside. The lens concentrator 10 is provided.

ただし、反射面７は平面であっても曲面であっても良い。また、少しの特性劣化が許容できるならば厳密に光軸を含む必要も無い。 However, the reflecting surface 7 may be a flat surface or a curved surface. Further, it is not necessary to strictly include the optical axis if slight characteristic deterioration can be allowed.

次に、本実施の形態の光軸を含む反射面７を有するレンズ集光器を使用して、軸ズレ平行入射光が受光面積の小さなＰｉｎ−ＰＤ（ＰｉｎＰｈｏｔｏＤｉｏｄｅ）やＡＰＤ（ＡｖａｌａｎｃｈｅＰｈｏｔｏｄｉｏｄｅ）などの受光素子に集光されるメカニズムを光線軌跡を使用して説明する。 Next, using the lens concentrator having the reflecting surface 7 including the optical axis of the present embodiment, Pin-PD (Pin Photo Diode) or APD (Avalanche Photodiode) having a small light-receiving area with respect to the axially shifted parallel incident light. A mechanism for focusing on a light receiving element such as the above will be described using a ray trajectory.

まず、図５に示す、対向する反射面での多重反射の従来タイプのレンズ集光器１１０の２次元モデルを使用して光線の軌跡について説明する。 First, the trajectory of light rays will be described using a two-dimensional model of a conventional type lens concentrator 110 of multiple reflection at opposing reflecting surfaces shown in FIG.

入射角１２（α）の軸ズレ平行入射光１１は、まずレンズ集光器１１０の入射側面５上でα₁方向に屈折し、第１反射面１５上の第１反射点１７で反射する。第１反射点での反射角をβ_１（第１反射角β_１＝π／２ −θ_１−α_１）とし、第１反射面１５と光軸３とのなす角度をθ₁とし、第１反射面１５と対向する第２反射面１６と光軸３とのなす角度をθ₂とすると、第２反射側面１６上の第２反射点１８での第２反射角β_２（β_２＝θ_１＋θ_２−β_１−π）は、次式で表される。 The axially shifted parallel incident light 11 having the incident angle 12 (α) is first refracted in the α ₁ direction on the incident side surface 5 of the lens concentrator 110 and reflected by the first reflection point 17 on the first reflection surface 15. The reflection angle at the first reflection point is β ₁ (first reflection angle β ₁ = π / 2 −θ ₁ −α ₁ ), the angle between the first reflection surface 15 and the optical axis 3 is θ ₁ , Assuming that the angle formed between the second reflection surface 16 facing the first reflection surface 15 and the optical axis 3 is θ ₂ , the second reflection angle β ₂ (β ₂ = β ₂₎ at the second reflection point 18 on the second reflection side surface 16. (θ ₁ + θ ₂ −β ₁ −π) is expressed by the following equation.

すなわち、β2＝０となるα1（式２）から計算するαが最大受光角となる。 That is, α calculated from α1 (formula 2) where β2 = 0 is the maximum light receiving angle.

ただし、αは次式のスネルの法則から導かれ、想定する入射角度範囲ではαとα_１は単調増加関係にあるので、最大受光角を最大屈折角α_１maxで代用する。 However, α is derived from Snell's law of the following equation, and α and α ₁ have a monotonically increasing relationship in the assumed incident angle range, and therefore the maximum light receiving angle is substituted with the maximum refraction angle α _1max .

以上の結果は、光軸対称な３次元光学系についても成立する。 The above results also hold for a three-dimensional optical system that is optically symmetric.

次に、図１に示す本願の実施の形態１の場合について光線軌跡を使用して説明する。 Next, the case of Embodiment 1 of the present application shown in FIG. 1 will be described using a ray trajectory.

光軸を含む反射面が存在していない従来例（図５参照）で、許容受光角範囲を超える入射角を有する軸ズレ平行入射光１１を考える。最初の反射点が、光軸を含む反射面が存在しない従来のレンズ集光器１１０の側面の場合は、光軸を含む反射面７が存在する本願の実施の形態１と比較して、第１反射点までの軌跡の相違は無い。 Consider axially shifted parallel incident light 11 having an incident angle exceeding the allowable light receiving angle range in a conventional example (see FIG. 5) in which no reflecting surface including the optical axis exists. In the case where the first reflection point is the side surface of the conventional lens concentrator 110 having no reflection surface including the optical axis, the first reflection point is compared with the first embodiment of the present application in which the reflection surface 7 including the optical axis is present. There is no difference in the trajectory up to one reflection point.

しかし、次式２’を満たす屈折角α_１の光線の第１反射点での反射後の軌跡は、従来例の場合は、レンズ集光器１１０の第１反射点を含む側面に対向する側面上の第２反射点まで進み、その後レンズ集光器の入射側面から外へ反射される。
すなわち上記の屈折角α_１は、式２から導かれる式２’の関係を満たしている。 However, the locus after reflection at the first reflection point of the light beam having the refraction angle α ₁ satisfying the following expression 2 ′ is the side surface facing the side surface including the first reflection point of the lens concentrator 110 in the conventional example. It proceeds to the upper second reflection point and is then reflected out of the incident side of the lens collector.
That is, the refraction angle α ₁ satisfies the relationship of Expression 2 ′ derived from Expression 2.

ここで、α_１max’は、従来のレンズ集光器１１０における最大屈折角を示す。 Here, α _1max ′ indicates the maximum refraction angle in the conventional lens concentrator 110.

一方、本願の実施の形態１の第１反射点での反射後の軌跡は、光軸を含む反射面上に第２反射点を有するので、第２反射点での反射後、第１反射点を有するレンズ集光器の側面上の第３反射点に向かって進み、最終的に受光素子に結合される。すなわち、本願の実施の形態１の場合は、式２においてθ_２=0となるので式４が成り立つ。 On the other hand, since the locus after reflection at the first reflection point in Embodiment 1 of the present application has the second reflection point on the reflection surface including the optical axis, the first reflection point after reflection at the second reflection point. Proceed toward the third reflection point on the side surface of the lens concentrator having, and finally coupled to the light receiving element. That is, in the case of the first embodiment of the present application, θ ₂ = 0 in equation 2, so that equation 4 holds.

この式４から、本願の実施の形態１のレンズ集光器１０の最大屈折角α_１maxの方が、従来の最大屈折角α_１max’よりも大きいことが分かり、本実施の形態の方が、従来より広い受光角を有すると言える。 From this equation 4, it can be seen that the maximum refraction angle α _1max of the lens concentrator 10 of Embodiment 1 of the present application is larger than the conventional maximum refraction angle α _1max ′. It can be said that it has a wider acceptance angle than before.

光軸を含む反射面が存在しない従来のレンズ集光器１１０の場合、反射点は全てレンズ集光器の側面上となるので上記の場合だけを検討すれば十分であるが、本実施の形態の場合は、最初の反射点が光軸を含む反射面７上の場合がある。 In the case of the conventional lens concentrator 110 having no reflecting surface including the optical axis, all the reflection points are on the side surfaces of the lens concentrator, so it is sufficient to consider only the above case. In this case, the first reflection point may be on the reflection surface 7 including the optical axis.

そこで、次にその場合の光線軌跡について説明する。即ち、その場合の光線軌跡は、最初の光軸を含む反射面７上の第１反射点での反射の後、レンズ集光器の側面上の第２反射点で反射し、光軸を含む反射面と第２の反射点を含むレンズ集光器の側面間で多重反射することで、最終的に受光素子に結合される。この場合は、式２においてθ_１=0となるので、次式４’の関係が成り立つ。 Therefore, the ray trajectory in that case will be described next. That is, the ray trajectory in that case is reflected at the second reflection point on the side surface of the lens concentrator after reflection at the first reflection point on the reflection surface 7 including the first optical axis, and includes the optical axis. Multiple reflection between the reflecting surface and the side surface of the lens concentrator including the second reflecting point finally couples to the light receiving element. In this case, since θ ₁ = 0 in Equation 2, the relationship of the following Equation 4 ′ holds.

よって式４’から、最初の反射点が光軸を含む反射面７上の場合であっても、光軸を含む反射面が無い従来の場合に比べて許容受光範囲広いことが分かる。 Therefore, it can be seen from Equation 4 'that even when the first reflection point is on the reflection surface 7 including the optical axis, the allowable light receiving range is wider than in the conventional case where there is no reflection surface including the optical axis.

尚、図１（ａ）、図１（ｂ）には、軸ズレ平行入射光１１の光線軌跡が反射面７で反射して出射側面６側に進む場合とともに、比較のために、入射側面５側から出ていく従来の光線軌跡１４も同時に表されている。 FIGS. 1A and 1B show the case where the ray trajectory of the axially shifted parallel incident light 11 is reflected by the reflecting surface 7 and proceeds to the exit side surface 6 side. A conventional ray trajectory 14 emanating from the side is also shown.

次に、本願の実施の形態１のレンズ集光器１０の作製方法について説明する。
即ち、従来のレンズ集光器１１０を、光軸３を含む面に沿って２分割した形状と同形状のものを用意し、反射面８を挟んだ状態で、接着しても良いし、固定冶具で保持しても良い。また、反射面８は、金属面や、ブラグ反射を利用した屈折率の周期構造や、レンズ集光器１０の導光部９の屈折率と異なる屈折率材料と導光部９の境界面での全反射構造などが挙げられる。 Next, a method for manufacturing the lens concentrator 10 of Embodiment 1 of the present application will be described.
That is, a conventional lens concentrator 110 having the same shape as that obtained by dividing the lens concentrator 110 into two along the surface including the optical axis 3 may be prepared, and may be bonded or fixed with the reflecting surface 8 interposed therebetween. You may hold with a jig. The reflective surface 8 is a metal surface, a periodic structure of refractive index using Bragg reflection, or a boundary surface between the refractive index material different from the refractive index of the light guide portion 9 of the lens concentrator 10 and the light guide portion 9. And a total reflection structure.

なお、レンズ集光器の出力面が受光素子のセンシング部分、例えば、半導体の活性層まで達していると高効率化が図れる。 In addition, when the output surface of the lens concentrator reaches the sensing portion of the light receiving element, for example, the active layer of the semiconductor, high efficiency can be achieved.

また、レンズ集光器の入射側面に接して、あるいは、出射側面と受光素子間に特定の波長のみを透過するフィルターを具備していても良い。 Further, a filter that transmits only a specific wavelength may be provided in contact with the incident side surface of the lens concentrator or between the emission side surface and the light receiving element.

このように、受光素子方向に断面が小さくなるレンズ集光器の側面だけでなく、光軸を含む面上にも反射面７を形成することで、レンズ集光器の側面の反射面への入射角をより大きくできるので、より広角での受光が可能となる。
（実施の形態２）
図２は、本発明に係る別の実施の形態の受光デバイスであって、光軸を含む２個の反射面を介して４個の導光部５９が接するレンズ集光器５０を具備する受光デバイスの構成を示す概要図である。尚、図２（ａ）は、受光デバイスの縦方向の断面を模式的に表した図であり、図２（ｂ）は、受光デバイスの光軸に垂直な断面から見た光線軌跡を説明するための模式図である。同図を用いて、本実施の形態の構成について上記実施の形態との相違点を中心に説明する。 Thus, by forming the reflecting surface 7 not only on the side surface of the lens concentrator whose cross section decreases in the direction of the light receiving element, but also on the surface including the optical axis, Since the incident angle can be made larger, light reception at a wider angle is possible.
(Embodiment 2)
FIG. 2 is a light receiving device according to another embodiment of the present invention, and includes a lens concentrator 50 in which four light guides 59 are in contact with each other through two reflecting surfaces including an optical axis. It is a schematic diagram which shows the structure of a device. 2A is a diagram schematically illustrating a longitudinal section of the light receiving device, and FIG. 2B illustrates a ray trajectory viewed from a section perpendicular to the optical axis of the light receiving device. It is a schematic diagram for. The configuration of the present embodiment will be described with reference to the same drawing, focusing on the differences from the above embodiment.

本願の実施の形態の受光デバイスは、図２（ｂ）に示すように、本願の実施の形態１の反射面７と、その反射面７との交線が光軸３と一致する第２の反射面１９を具備し、４個の導光部５９で構成されるレンズ集光器５０を備えた点において図１の構成と異なる。 As shown in FIG. 2B, the light receiving device according to the embodiment of the present application has a second reflecting surface 7 according to the first embodiment of the present application and a line of intersection between the reflecting surface 7 and the optical axis 3. 1 is different from the configuration of FIG. 1 in that a reflecting surface 19 is provided and a lens concentrator 50 including four light guides 59 is provided.

上記実施の形態１において、入射側面における入射光と透過光を含む面（本明細書では、この面を入射面と定義し、以下、入射面と呼ぶ。）が、光軸３から遠くない入射光は第１反射点と第２反射点のいずれかが必ず光軸を含む反射面７，１９上にあるので、光軸を含む反射面７が１個（図１（ｂ）参照）でも従来よりも受光角が広がるといえる。 In the first embodiment, an incident side surface that includes incident light and transmitted light (this surface is defined as an incident surface, hereinafter referred to as an incident surface) is not far from the optical axis 3. Since either one of the first reflection point and the second reflection point is necessarily on the reflection surfaces 7 and 19 including the optical axis, even if there is one reflection surface 7 including the optical axis (see FIG. 1B), It can be said that the acceptance angle is wider than that.

しかし、図１の構成では、入射側面における入射面が光軸３から遠い入射光は、レンズ集光器１０から入射側面側に出ていってしまう場合がある。そのことを、図２（ｂ）を代用して説明する。 However, in the configuration of FIG. 1, incident light whose incident surface on the incident side surface is far from the optical axis 3 may be emitted from the lens collector 10 toward the incident side surface. This will be described with reference to FIG.

即ち、図１のレンズ集光器１０の構成は、例えば図２（ｂ）の構成で第２反射面１９が存在しないとした場合と等価であるから、光軸を含む第２反射面１９が無い場合の光線軌跡２０を図２（ｂ）に示すとすれば、レンズ集光器５０の側面上の第１反射点３０で反射した光線は破線で示すように、同じ導光部５９のレンズ集光器５０の側面上に第２反射点３１を有することになる。そしてこの光線は、第２反射点３１から入射側面５側へ戻ってしまう。従ってこの場合、許容受光角度は従来のレンズ集光器１１０と同じとなる。 That is, the configuration of the lens concentrator 10 in FIG. 1 is equivalent to, for example, the case where the second reflecting surface 19 does not exist in the configuration in FIG. If the ray trajectory 20 when there is no light is shown in FIG. 2B, the light beam reflected by the first reflection point 30 on the side surface of the lens concentrator 50 is the lens of the same light guide 59 as shown by the broken line. The second reflection point 31 is provided on the side surface of the condenser 50. Then, this light beam returns from the second reflection point 31 to the incident side surface 5 side. Therefore, in this case, the allowable light receiving angle is the same as that of the conventional lens concentrator 110.

そこで、入射側面における入射面が光軸から遠い入射光でも、第２反射点が、第１反射点と同じ導光部のレンズ集光器の側面上に来ないように、光軸を含む反射面７，１９を複数個設けたのが実施の形態２である。 Therefore, even if the incident surface on the incident side is far from the optical axis, the reflection including the optical axis is performed so that the second reflection point does not come on the side surface of the lens concentrator of the same light guide unit as the first reflection point. In the second embodiment, a plurality of surfaces 7 and 19 are provided.

光軸を含む反射面の数は多いほど良いが、図２のように２個にしてレンズ集光器５０の導光部５９を４個にすれば、光軸を含む反射面が１個の構成では受光できない入射光でも、図２（ｂ）に示すように第２反射点３２が光軸を含む反射面１９上になるので、受光素子４に結合できる。なお、光軸を含む反射面７，１９の配置は光軸３に対して対称であることが望ましい。 The larger the number of reflection surfaces including the optical axis, the better. However, if the number of the light guide portions 59 of the lens concentrator 50 is four as shown in FIG. 2, the number of reflection surfaces including the optical axis is one. Even incident light that cannot be received by the configuration can be coupled to the light receiving element 4 because the second reflection point 32 is on the reflection surface 19 including the optical axis as shown in FIG. The arrangement of the reflecting surfaces 7 and 19 including the optical axis is preferably symmetric with respect to the optical axis 3.

このように、光軸を含む反射面を複数個にすることで入射側面における入射面が光軸から遠い入射光に対しても、上記実施の形態１の構成より広角での受光が可能となる。 Thus, by using a plurality of reflecting surfaces including the optical axis, it is possible to receive light at a wider angle than the configuration of the first embodiment, even for incident light whose incident surface on the incident side surface is far from the optical axis. .

尚、本実施の形態のレンズ集光器５０の作製方法は、従来のレンズ集光器１１０を光軸３を含む面に沿って４分割した形状と同形状のものを用意しさえすれば、その後の工程は、上記実施の形態１で説明した場合と基本的には同じである。
（実施の形態３）
図３は、本発明に係る別の実施の形態の受光デバイスであって、光軸を中心に対向する平行な反射面で構成される有限反射面２１を介して４個の導光部６９が接するレンズ集光器６０を具備する受光デバイスの構成概要図である。尚、図３（ａ）は、受光デバイスの光軸３を含むＡ−Ａ’断面（図３（ｂ）参照）を模式的に表した図であり、図３（ｂ）は、受光デバイスの光軸に垂直な断面において光線軌跡を模式的に示した図である。同図を用いて、本実施の形態の構成について上記実施の形態との相違点を中心に説明する。 The lens concentrator 50 according to the present embodiment can be manufactured by preparing a lens concentrator 110 having the same shape as the conventional lens concentrator 110 divided into four along the plane including the optical axis 3. Subsequent steps are basically the same as those described in the first embodiment.
(Embodiment 3)
FIG. 3 shows a light receiving device according to another embodiment of the present invention, in which four light guides 69 are arranged via a finite reflection surface 21 composed of parallel reflection surfaces facing the optical axis as a center. It is a structure schematic diagram of the light receiving device which comprises the lens concentrator 60 which touches. 3A is a diagram schematically showing a cross section taken along line AA ′ including the optical axis 3 of the light receiving device (see FIG. 3B). FIG. 3B is a diagram illustrating the light receiving device. It is the figure which showed typically the light ray locus in the cross section perpendicular | vertical to an optical axis. The configuration of the present embodiment will be described with reference to the same drawing, focusing on the differences from the above embodiment.

本願の実施の形態の受光デバイスは、図３に示すように、上記実施の形態２で説明した反射面７，１９の内部に導波路構造の導光部分を有する構成と等価であり、上記の反射面７，１９を、対向する反射面で構成された有限反射面２１と有限反射面内の導光部分２２とに置き換えた構成である。 As shown in FIG. 3, the light receiving device according to the embodiment of the present application is equivalent to the configuration having the light guide portion of the waveguide structure inside the reflecting surfaces 7 and 19 described in the second embodiment. In this configuration, the reflecting surfaces 7 and 19 are replaced with a finite reflecting surface 21 configured with opposing reflecting surfaces and a light guide portion 22 within the finite reflecting surface.

本実施の形態のレンズ集光器６０の作製方法は、有限反射面内の導光部分２２の部分を除き上述した実施の形態２の場合と基本的には同じである。 The manufacturing method of the lens concentrator 60 of the present embodiment is basically the same as that of the second embodiment described above except for the light guide portion 22 in the finite reflection surface.

有限反射面内の導光部分２２は、上述した作製方法で用いた接着層の厚みを厚めに制御して作製してもよいし、ガラス材料又は樹脂材料等を用いて金型で成形したものを４分割されたレンズ集光器の間に挟み込む様にして作製しても良い。成形材料は、導光部６９と同一でも良いし異なっていても良い。あるいは、単に空気層を設けるだけでも良い。 The light guide portion 22 in the finite reflection surface may be manufactured by controlling the thickness of the adhesive layer used in the above-described manufacturing method to be thick, or formed by a mold using a glass material or a resin material. May be made to be sandwiched between four lens concentrators. The molding material may be the same as or different from that of the light guide unit 69. Alternatively, an air layer may be simply provided.

このように、上記実施の形態と同じ許容受光角を有するレンズ集光器６０の導光部６９の他に、式２においてθ_１＝θ_２＝０を代入した場合と等価な関係となる、光軸を含む有限反射面内の導光部分２２が構成されている。この導光部分２２は、上記実施の形態の構成には存在しないため、光軸近傍の有限反射面内の導光部分２２に入射する光は、上記実施の形態よりもより広い受光角を有することになる。 Thus, in addition to the light guide portion 69 of the lens concentrator 60 having the same allowable light receiving angle as that of the above embodiment, the relationship is equivalent to the case where θ ₁ = θ ₂ = 0 is substituted in Equation ₂ . A light guide portion 22 in the finite reflection surface including the optical axis is configured. Since this light guide portion 22 does not exist in the configuration of the above embodiment, the light incident on the light guide portion 22 in the finite reflection surface near the optical axis has a wider light receiving angle than the above embodiment. It will be.

この有限反射面内の導光部分２２の断面が大きくなるほど、上記実施の形態の許容受光角よりも受光角の大きな部分の割合が増えるので、レンズ集光器６０全体の許容受光角が大きくなる。尚、図３（ｂ）に光線軌跡を示す。ここで、図３（ｂ）の破線部分は、光線が反射を繰り返すことを表現したものであり、反射を繰り返して最終的には受光素子４に到達する。
（実施の形態４）
図４は、本発明に係る別の実施の形態の受光デバイスであって、光軸を中心に対向する湾曲した反射面で構成される有限反射面１２１を介して４個の導光部７９が接するレンズ集光器７０を具備する受光デバイスの構成概要図である。同図を用いて、本実施の形態の構成について上記実施の形態との相違点を中心に説明する。 As the cross section of the light guide portion 22 in the finite reflection surface increases, the ratio of the portion having a larger light reception angle than the allowable light reception angle of the above-described embodiment increases, so that the allowable light reception angle of the entire lens condenser 60 increases. . FIG. 3B shows the ray trajectory. Here, the broken line portion in FIG. 3B represents that the light beam repeats reflection, and finally reaches the light receiving element 4 by repeating the reflection.
(Embodiment 4)
FIG. 4 shows a light receiving device according to another embodiment of the present invention, in which four light guides 79 are arranged via a finite reflection surface 121 formed of a curved reflection surface facing the optical axis as a center. It is a structure schematic diagram of the light receiving device which comprises the lens concentrator 70 which touches. The configuration of the present embodiment will be described with reference to the same drawing, focusing on the differences from the above embodiment.

本願の実施の形態４は、上記実施の形態３の有限反射面内の導光部分２２の光軸３に垂直な断面の面積を受光素子４に向かうに従って小さくした例である（図４（ｂ）、（ｃ）参照）。 Embodiment 4 of the present application is an example in which the area of the cross section perpendicular to the optical axis 3 of the light guide portion 22 in the finite reflection surface of Embodiment 3 is made smaller toward the light receiving element 4 (FIG. 4B). ) And (c)).

ここで、図４（ａ）は、受光デバイスの光軸３を含むＡ−Ａ’断面（図３（ｂ）参照）を模式的に表した図であり、図４（ｂ）は、受光デバイスの光軸に垂直な断面において光線軌跡を模式的に示した図である。図４（ｃ）は、有限反射面内の導光部分１２２の断面の変化を説明するために、図４（ｂ）によりも受光素子４に近い位置における光軸３に垂直な断面を示した模式図である。 Here, FIG. 4A is a diagram schematically showing an AA ′ cross section (see FIG. 3B) including the optical axis 3 of the light receiving device, and FIG. It is the figure which showed typically the light ray locus in the cross section perpendicular | vertical to the optical axis. FIG. 4C shows a cross section perpendicular to the optical axis 3 at a position closer to the light receiving element 4 than in FIG. 4B in order to explain the change in the cross section of the light guide portion 122 in the finite reflection surface. It is a schematic diagram.

本実施の形態の場合、有限反射面内の導光部分１２２の許容受光角は実施の形態３に比べて小さくなるが、レンズ集光器７０を構成する導光部７９は式２において、第２傾斜角θ_２が負の値となるので、第２傾斜角θ_２＝０となる実施の形態１〜実施の形態３よりも許容受光角が大きい。その理由を以下に説明する。 In the case of the present embodiment, the allowable light receiving angle of the light guide portion 122 in the finite reflection surface is smaller than that in the third embodiment, but the light guide portion 79 constituting the lens concentrator 70 is Since the 2 tilt angle θ ₂ has a negative value, the allowable light receiving angle is larger than those in the first to third embodiments in which the second tilt angle θ ₂ = 0. The reason will be described below.

ここで、図４において導光部７９ではθ_１＞０、θ_２＜０となるが、有限反射面内の導光部分１２２は対向する面の曲率が異符号となるためθ_１＞０、θ_２＞０となる。なぜなら、図５でラッパ状に広がっている場合をθ_１＞０、θ_２＞０で同符号と定義しているからである。 Here, in the light guide unit 79 in FIG. 4, θ ₁ > 0 and θ ₂ <0. However, since the curvature of the facing surface of the light guide portion 122 in the finite reflection surface is different, θ ₁ > 0, θ ₂ > 0. This is because in FIG. 5, the case of spreading in a trumpet is defined as the same sign with θ ₁ > 0 and θ ₂ > 0.

即ち、実施の形態４の有限反射面の導光部分１２２の場合は、θ_１＞０、θ_２＞０となるので、図３で述べた導光部分２２の最大屈折角、図４で述べた導光部分１２２の最大屈折角をそれぞれα_{１max（22）}、α_{１max（122）}と表すとすると、式２より、次の式が導ける。 That is, in the case of the light guide portion 122 of the finite reflection surface of the fourth embodiment, θ ₁ > 0 and θ ₂ > 0, so that the maximum refraction angle of the light guide portion 22 described in FIG. If the maximum refraction angles of the light guide portion 122 are _expressed as α _{1max (22)} and α _{1max (122)} , respectively, the following equation can be derived from Equation 2.

よって、式５からα_{１max（１22）}＜α_{１max（22）}の関係が成り立つので、本実施の形態の導光部分１２２の許容受光角の方が、実施の形態３の導光部分２２の許容受光角に比べて小さくなることが分かる。 Therefore, since the relationship of α _{1max (122)} <α _{1max (22)} is _established from Expression 5, the allowable light receiving angle of the light guide portion 122 of the present embodiment is the allowable value of the light guide portion 22 of the third embodiment. It can be seen that it is smaller than the light receiving angle.

したがって、本実施の形態の有限反射面内の導光部分１２２の断面形状が小さい場合には導光部分１２２の影響は小さくなり、導光部７９の全体に占める割合が、実施の形態３の場合より大きくなり得るため、実施の形態３よりも効果的に許容受光角を広げることができる。 Therefore, when the cross-sectional shape of the light guide portion 122 in the finite reflection surface of the present embodiment is small, the influence of the light guide portion 122 is small, and the proportion of the entire light guide portion 79 is the same as that of the third embodiment. Since it can be larger than the case, the allowable light receiving angle can be increased more effectively than in the third embodiment.

このように、受光素子方向に断面が小さくなるレンズ集光器の側面だけでなく、光軸を含む面上にも反射面を形成することで、レンズ集光器の側面の反射面への入射角をより大きくできるので、より広角での受光が可能となる。 In this way, the reflecting surface is formed not only on the side surface of the lens concentrator whose cross section is reduced in the direction of the light receiving element but also on the surface including the optical axis, so that the incident light is incident on the reflecting surface on the side surface of the lens concentrator Since the angle can be made larger, light can be received at a wider angle.

以上説明した様に本発明は、例えば、光源から自由空間で隔てられた受光素子と、受光素子の入力端の近傍に配置し、反射機能を有する側面の対向する間隔が受光素子方向に向かって小さくなり、内部に入射側面と出射側面を分割する少なくとも一つの反射面を具備するレンズ集光器で構成される。 As described above, the present invention is arranged, for example, in the vicinity of the light receiving element separated from the light source in free space and the input end of the light receiving element, and the distance between the opposing side surfaces having the reflecting function is directed toward the light receiving element. The lens concentrator is made smaller and includes at least one reflecting surface that divides the incident side surface and the output side surface.

このように、レンズ集光器の側面だけでなく、レンズ集光器の内部にも入射側面と出射側面を分割する反射面を形成することにより、レンズ集光器への入射角をより大きくできるので、より広角での受光が可能となり、より広い受光角範囲で高速光空間伝送を可能とする光学系を提供できるという効果を有する。 In this way, by forming a reflection surface that divides the incident side surface and the output side surface not only on the side surface of the lens concentrator but also inside the lens concentrator, the incident angle to the lens concentrator can be further increased. As a result, it is possible to receive light at a wider angle and to provide an optical system capable of high-speed optical space transmission in a wider light reception angle range.

尚、上記実施の形態では、レンズ集光器の内部に、入射側面から出射側面に亘る全範囲において側面の反射面と実質上対面する反射面（例えば、図１の光軸を含む反射面７）が設けられている場合について説明したが、これに限らず例えば、入射側面の近傍及び／又は出射側面の近傍を除く範囲において本発明の反射面が設けられていてもかまわない。要するに、レンズ集光器への入射角をより大きくできる構成であれば、集光器の内部に、入射側面から出射側面に亘る一部の範囲において反射機能を有する側面と実質上対面する反射面が設けられている構成であってもよい。 In the above-described embodiment, a reflecting surface (for example, the reflecting surface 7 including the optical axis in FIG. 1) that substantially faces the reflecting surface of the side surface in the entire range from the incident side surface to the exit side surface is provided inside the lens concentrator. However, the present invention is not limited to this. For example, the reflective surface of the present invention may be provided in a range excluding the vicinity of the incident side surface and / or the vicinity of the output side surface. In short, as long as the angle of incidence on the lens concentrator can be increased, a reflecting surface that substantially faces the side surface having a reflecting function in a part of the range from the incident side surface to the output side surface within the concentrator. May be provided.

又、上記実施の形態では、出射側面と受光素子とが接触している場合について説明したが、これに限らず例えば、双方の間に空間が存在しても良い。 In the above-described embodiment, the case where the emission side surface and the light receiving element are in contact with each other has been described. However, the present invention is not limited to this. For example, a space may exist between the two.

又、上記実施の形態では、レンズ集光器の入射側面が曲面であって出射側面が平面である場合について説明したが、これに限らず例えば、出射側面が曲面であってもよい。 Moreover, although the said embodiment demonstrated the case where the entrance side surface of a lens concentrator is a curved surface and the output side surface is a plane, it is not restricted to this, For example, an exit side surface may be a curved surface.

又、上記実施の形態では、導光部あるいは有限反射面内の導光部分の材料としてガラスや樹脂などを用いる場合を中心に説明したが、これに限らず例えば、前記集光器内に、光ファイバーアンプ（増幅器）のようにエリビュウム（Ｅｒ）やＹｂ（イットリビウム）などを添加したり、ラマン増幅効果を利用して外部から励起光に伴う誘導放出を起こすことで受光素子への入射光を増幅してもよい。 Further, in the above embodiment, the explanation has been made mainly on the case where glass or resin is used as the material of the light guide part or the light guide part in the finite reflection surface, but not limited thereto, for example, in the light collector, Adds erbium (Er), Yb (yttrium), etc. like an optical fiber amplifier (amplifier), or amplifies the incident light to the light receiving element by causing stimulated emission from the outside using the Raman amplification effect. May be.

又、レンズ集光器の内部に、入射側面から出射側面に亘る全部又は一部の範囲において側面の反射面と実質上対面する反射面が設けられている構成例について、上記実施の形態で述べた例（例えば、図１の光軸を含む反射面７）の他に、例えば、断面がリング形状で対面するレンズ集光器の側面との間隔が、受光素子に向かって小さくなる構成も考えられる。即ち、具体的には、レンズ集光器の側面と同心円状の反射面（図示せず）等が挙げられるが、入射側面における入射光と、レンズ集光器内に入った透過光を含む面が光軸から離れている入射光は、第１反射点と第２反射点の両方がレンズ集光器の側面上となる割合が上記実施の形態のように断面がリング形状とならない場合よりも大きいので、受光角の拡大の効果はあまり大きくない。 Further, in the above-described embodiment, a configuration example in which a reflective surface that substantially faces the reflective surface of the side surface is provided in the whole or a part of the range from the incident side surface to the output side surface inside the lens concentrator is described. In addition to the example (for example, the reflecting surface 7 including the optical axis in FIG. 1), for example, a configuration in which the distance from the side surface of the lens concentrator facing in a ring shape becomes smaller toward the light receiving element is also conceivable. It is done. Specifically, a reflecting surface (not shown) concentric with the side surface of the lens concentrator can be mentioned, but a surface including incident light on the incident side surface and transmitted light entering the lens concentrator. The incident light that is away from the optical axis has a ratio that both the first reflection point and the second reflection point are on the side surface of the lens concentrator than in the case where the cross section does not have a ring shape as in the above embodiment. Since it is large, the effect of expanding the light receiving angle is not so great.

本発明の受光デバイスは、より広い角度範囲で軸ズレ入射光を受光できるという効果を有し、光空間伝送等に使用される受光デバイス等として有用である。 The light receiving device of the present invention has an effect of receiving axially shifted incident light in a wider angle range, and is useful as a light receiving device used for optical space transmission or the like.

（ａ）実施の形態１の受光デバイスの縦方向の断面を模式的に表した図，（ｂ）同実施の形態の受光デバイスの光軸に垂直な断面から見た光線軌跡を説明するための模式図(A) The figure which represented typically the cross section of the vertical direction of the light receiving device of Embodiment 1, (b) For demonstrating the light ray locus seen from the cross section perpendicular | vertical to the optical axis of the light receiving device of the same embodiment Pattern diagram （ａ）実施の形態２の受光デバイスの縦方向の断面を模式的に表した図，（ｂ）同実施の形態の受光デバイスの光軸に垂直な断面から見た光線軌跡を説明するための模式図(A) The figure which represented typically the cross section of the vertical direction of the light receiving device of Embodiment 2, (b) For demonstrating the light ray locus seen from the cross section perpendicular | vertical to the optical axis of the light receiving device of the same embodiment Pattern diagram （ａ）実施の形態３の受光デバイスの光軸を含むＡ−Ａ’断面を模式的に表した図，（ｂ）同実施の形態の受光デバイスの光軸に垂直な断面において光線軌跡を模式的に示した図(A) The figure which represented typically the AA 'cross section containing the optical axis of the light receiving device of Embodiment 3, (b) Schematic of a light ray locus in the cross section perpendicular | vertical to the optical axis of the light receiving device of the same embodiment. Diagram （ａ）実施の形態４の受光デバイスの光軸を含むＡ−Ａ’断面を模式的に表した図，（ｂ）同実施の形態の受光デバイスの光軸に垂直な断面において光線軌跡を模式的に示した図，（ｃ）同実施の形態の有限反射面内の導光部分の断面の変化を説明するための図(A) The figure which represented typically the AA 'cross section containing the optical axis of the light receiving device of Embodiment 4, (b) Schematic of a light ray locus in the cross section perpendicular | vertical to the optical axis of the light receiving device of the same embodiment. (C) The figure for demonstrating the change of the cross section of the light guide part in the finite reflection surface of the embodiment 従来の受光デバイスでの対向する反射面での多重反射による光線軌跡の説明図Explanatory drawing of ray trajectory due to multiple reflections at opposing reflecting surfaces in a conventional light receiving device

符号の説明Explanation of symbols

１光源
２自由空間
３光軸
４受光素子
５入射側面
６出射側面
７光軸を含む反射面
８側面の反射面
９、５９，６９，７９導光部
１０レンズ集光器
１１軸ズレ（平行）入射光
１２入射角
１３光線軌跡
１４従来の光線軌跡
１５第１反射面
１６第２反射面
１７第１反射点
１８第２反射点
１９光軸を含む第２反射面
２０光軸を含む第２反射面が無い場合の光線軌跡
２１、１２１有限反射面
２２、１２２有限反射面内の導光部分 DESCRIPTION OF SYMBOLS 1 Light source 2 Free space 3 Optical axis 4 Light receiving element 5 Incident side surface 6 Outgoing side surface 7 Reflecting surface including an optical axis 8 Side reflecting surface 9, 59, 69, 79 Light guide part 10 Lens concentrator 11 Axis deviation (parallel) Incident light 12 Incident angle 13 Ray trajectory 14 Conventional ray trajectory 15 First reflecting surface 16 Second reflecting surface 17 First reflecting point 18 Second reflecting point 19 Second reflecting surface including optical axis 20 Second reflecting including optical axis Ray trajectory with no surface
21, 121 Finite reflective surface 22, 122 Light guiding part in the finite reflective surface

Claims

光源からの出射光を集光して出射する集光器と、前記集光器からの出射光を受光する受光素子とを備えた受光デバイスであって、
前記集光器は、両端に入射側面と出射側面とを有し、前記入射側面から入射した光を反射させる反射機能を有する側面の内部が前記入射側面から前記出射側面に向かうに従って実質上せまくなっており、前記集光器の内部には、前記入射側面から前記出射側面に亘る全部又は一部の範囲において前記側面と実質上対面する反射面が設けられている受光デバイス。 A light receiving device comprising: a light collecting device that collects and emits light emitted from a light source; and a light receiving element that receives light emitted from the light collecting device,
The concentrator has an incident side surface and an exit side surface at both ends, and the inside of the side surface having a reflection function for reflecting light incident from the incident side surface becomes substantially narrower as it goes from the incident side surface to the exit side surface. The light receiving device is provided with a reflecting surface that substantially faces the side surface in the whole or a part of the range from the incident side surface to the emission side surface.

前記反射面が前記集光器の光軸を含む請求項１に記載の受光デバイス。 The light receiving device according to claim 1, wherein the reflecting surface includes an optical axis of the condenser.

前記反射面が複数であって、前記反射面同士の交線が存在する請求項１に記載の受光デバイス。 The light receiving device according to claim 1, wherein there are a plurality of reflecting surfaces, and there are intersecting lines between the reflecting surfaces.

前記複数の反射面の前記交線が、前記集光器の光軸に平行である請求項３に記載の受光デバイス。 The light receiving device according to claim 3, wherein the intersecting line of the plurality of reflecting surfaces is parallel to an optical axis of the condenser.

前記反射面が複数であって、前記反射面同士の交線が存在しない請求項１に記載の受光デバイス。 The light receiving device according to claim 1, wherein there are a plurality of the reflecting surfaces, and there are no intersecting lines between the reflecting surfaces.

前記集光器の光軸に対する前記反射面の傾斜の程度が、前記入射側面から前記出射側面に向かうに従って小さくなる請求項５に記載の受光デバイス。 The light receiving device according to claim 5, wherein the degree of inclination of the reflecting surface with respect to the optical axis of the condenser decreases from the incident side surface toward the emitting side surface.

前記反射面が金属面で形成されている請求項１に記載の受光デバイス。 The light receiving device according to claim 1, wherein the reflecting surface is formed of a metal surface.

前記反射面がブラグ反射を起こす周期構造で形成されている請求項１に記載の受光デバイス。 The light receiving device according to claim 1, wherein the reflecting surface is formed with a periodic structure that causes Bragg reflection.

前記反射面が、前記集光器と異なる屈折率を有する材料との全反射を起こす界面で形成
されている請求項１に記載の受光デバイス。 The light receiving device according to claim 1, wherein the reflection surface is formed at an interface that causes total reflection between the light collector and a material having a different refractive index.

前記集光器の前記入射側面と前記出射側面との少なくとも一方が曲面である請求項１〜９の何れかに記載の受光デバイス。 The light receiving device according to claim 1, wherein at least one of the incident side surface and the emission side surface of the light collector is a curved surface.

前記集光器の前記入射側面に、又は前記出射側面と前記受光素子との間に、特定の波長のみを透過するフィルターを備えた請求項１〜１０の何れかに記載の受光デバイス。 The light receiving device according to claim 1, further comprising a filter that transmits only a specific wavelength on the incident side surface of the light collector or between the light emitting side surface and the light receiving element.