IMPROVEMENTS OF AN OPTICAL SENSING SYSTEM OF A DRUG DELIVERY DEVICE

Optical guiding means (10) configured for application with a drug delivery device having a movable dosage programming component (12) comprising a rotary encoder system and a sensor arrangement (14) comprising at least one optical sensor (16, 16') configured to detect movement of the movable dosage programming component (12) relative to the sensor arrangement (14) during dosing of a drug by emitting radiation (18, 18') and detecting reflections (20, 20') of the emitted radiation from the rotary encoder system, wherein the optical guiding means (10) are configured for guiding the radiation (18, 18') and reflections (20, 20') of the emitted radiation and comprise at least one light pipe (100, 100') having the shape of a frustum with a sensor-side surface (102, 102') and a encoder-side surface (104,104'). The at least one light pipe comprises one or more of the following features: the ratio of the sensor-side surface (102) and the encoder-side surface (104) being equal to or larger than about 1.0; the ratio of the surface (24) of a discreet encoding target (22) of the rotary encoder system and the encoder-side surface (104) being equal to or larger than 1.0; the encoder-side surface (104) having a roughness with an average feature size in the range of the wavelength of the radiation emitted by the at least one optical sensor (16, 16'); the sensor-side surface forms a single lens face (26) being moulded as part of the optical guiding means (10), wherein the single lens face (26) is formed as collimating optics. La présente invention concerne des moyens de guidage optique (10) conçus pour une application avec un dispositif d'administration de médicament. Lesdits moyens de guidage optique (10) comprennent : un composant de programmation de dosage mobile (12) équipé d'un système de codeur rotatif ; et un dispositif capteur (14) équipé d'au moins un capteur optique (16, 16'). Ce dernier est conçu pour détecter un mouvement du composant de programmation de dosage mobile (12) par rapport au dispositif capteur (14) pendant un dosage d'un médicament en émettant un rayonnement (18, 18') et en détectant des réflexions (20, 20') du rayonnement émis provenant du système de codeur rotatif. Les moyens de guidage optique (10) sont conçus pour guider le rayonnement (18, 18') et les réflexions (20, 20') du rayonnement émis. Les moyens de guidage optique (10) comprennent au moins un conduit de lumière (100, 100') se présentant la forme d'un cône tronqué pourvu d'une surface côté