Abstract:
Mapping apparatus includes a transmitter, which emits a beam comprising pulses of light, and a scanner, which is configured to scan the beam, within a predefined scan range, over a scene. A receiver receives the light reflected from the scene and to generate an output indicative of a time of flight of the pulses to and from points in the scene. A processor is coupled to control the scanner so as to cause the beam to scan over a selected window within the scan range and to process the output of the receiver so as to generate a 3D map of a part of the scene that is within the selected window.
Abstract:
Apparatus for detecting particulates (46) within a medium in a chamber (10) comprises a photo-detector (14) which is maintained at a stable low temperature by a Peltier type cooling device (42). Scattered light from the particulate (46) is focussed by a spherical lens (34) onto the input face (30) of a rod lens (22). The latter has an optical pitch of 0.5 and transfers the image to its output face (25) whence it passes via a light pipe (18) to the sensitive area (16) of the photo-electric device (14). The rod lens (22) provides an inexpensive means for transferring the light and which provides a thermal barrier. Thus, although the photo-electric device (14) is held at a low temperature, the input face (30) of the rod lens (22) can be held at the temperature of the medium within the chamber (10) and is not subjected to the formation of mist or ice. The lens (34) is mounted by means of a collar (28) which is slidable into a position in which the lens (34) focusses the input light onto the face (30) of the lens (22), and then secured in this position by ultra-violet-cured adhesive fillets (32, 34).
Abstract:
An avalanche photodiode quenching circuit (20) incorporates an avalanche photodiode (APD) (22) and a first comparator (C1) responsive to reduction in APD voltage. The comparator (C1) is arranged to activate an APD quench circuit (38) in response to APD avalanche initiation. The circuit (20) also includes a second comparator (C2) arranged to reset the first comparator input (N2) in response to a further reduction in APD voltage caused by initiation of quenching. The second comparator (C2) is also connected to a monostable circuit (48) arranged to latch the first comparator output response to resetting. The monostable circuit (48) maintains the first comparator output level constant until the APD (22) has recharged.
Abstract:
An avalanche photodiode quenching circuit (10) comprises a low value photodiode series resistor (20) and a comparator amplifier (40). The comparator (40) compares the photodiode potential with a reference voltage and changes state rapidly after initiation of a photodiode avalanche. The photodiode (12) is actively quenched by taking its potential below breakdown. This is achieved by a fast-switching transistor (30) activated by avalanche detection at the comparator. A further fast-switching transistor (42) is arranged to reset the comparator input (38) after a preset delay following avalanche detection. The photodiode (12) recharges passively through the series resistor (20) at a rapid rate since this resistor has a low value. The transistors (30) and (42) are diactivated by comparator reset, the latter after the preset delay once more, and are isolated from the photodiode (12) during recharge by diodes (16) and (18). The invention avoids the use of active photodiode reset pulses, and has constant output pulse width and well-defined dead-time.
Abstract:
Appareil de contrôle permettant d'effectuer des tests sur des échantillons qui comprend une chambre d'échantillon dans laquelle on place un récipient contenant une substance luminescente, et une photodiode à avalanche qui enregistre la lumière émise, que mesure ensuite un circuit auquel la photodiode est connectée. Grâce à l'utilisation d'une photodiode à avalanche, l'appareil de contrôle est solide et transportable, de sorte qu'on peut l'intégrer dans un nécessaire portatif pour effectuer sur place des contrôles d'hygiène.
Abstract:
Die Erfindung betrifft einen positonsempfindlichen Fotodetektor zur Erfassung der ortsbezogenen Intensitätsverteilung von einer auf einer Empfängerfläche erzeugten Abbildung, wie er insbesondere für die LaserTriangulation verwendet werden kann. Durch die Trennung von Empfängerfläche (2) und optoelektronischen Wandlern (3) durch zwischengeschaltete Lichtleiter (1) und durch das Vorhandensein einer Vielzahl von Lichtleitern innerhalb einer Empfängerfläche (2) wird eine hochaufgelöste Verarbeitung einer auf der Empfängerfläche (2) vorhandenen Abbildung, beispielsweise einem Lichtfleck (6) bei gleichzeitiger Auslesung mittels sämtlicher Lichtleiter 1.1 bis 1.n von der Empfängerfläche ermöglicht. Somit ist eine parallele Verarbeitung der in jedem Element innerhalb der Empfängerfläche (2) gleichzeitig vorhandenen Signale, wie beispielsweise dem Lichtfleck (6), ohne Verzögerung möglich. Die örtliche Zuordnung richtet sich auf die detektorbezogene Koordinatenrichtung (X).
Abstract:
The quenching circuit comprises a signal comparator (CP) having a first input connected to the photodiode (SPAD) under control and a second input connected to a balancing impedance (C) equal to that of the photodiode. At the output of the comparator (CP) there is connected a signal generator (M), which generates a quenching signal (S) having a predetermined duration each time there is an imbalance between the two inputs of the comparator. Circuital switching means (I1, I2, I3, I4) are provided, capable of holding the bias voltage of the photodiode normally high and of lowering it below the breakdown level following the generation and for the entire holding time of said quenching signal.
Abstract:
맵핑 장치(22)는 광의 펄스들을 포함하는 빔을 방출하는 송광기(44), 및 신에 걸쳐, 사전규정된 스캔 범위 내에서, 빔(38)을 스캐닝하도록 구성된 스캐너(46)를 포함한다. 수광기(48)는 신으로부터 반사되는 광을 수광하고, 신 내의 점들로의 및 그들로부터의 펄스들의 비행 시간을 나타내는 출력을 생성한다. 프로세서(42)는 빔으로 하여금 스캔 범위 내의 선택된 윈도우(32, 34, 36)에 걸쳐 스캐닝하게 하도록 스캐너를 제어하기 위해, 그리고 선택된 윈도우 내에 있는 신의 일부의 3D 맵을 생성하도록 수광기의 출력을 처리하기 위해 결합된다.