Koninklijke Philips Corporation N.v.

Ivon Franciscus Helwegen

Stein Kuiper

Bernardus H W Hendriks

Hans Willem Van Kesteren

Marco A J Van As

Bart Michiel De Boer

Christina Adriana Renders

Jeroen Kalkman

Albert H J Immink

Bart M De Boer

A photo acoustic detector for detecting a concentration of a sample in a mixture includes a light source for producing a light beam for exciting molecules of the sample, and a light modulator for modulating the light beam for generating pressure variations in the sample mixture, where an amplitude of the pressure variations is a measure of the concentration. The detector further includes a detector element for converting the pressure variations into a detector current and a processing section for processing the detector current to generate an output signal representing the concentration. The processing section includes an integrating amplifier for integrating the detector current, the integrating amplifier being coupled to the detector element via a hold switch, and a timing circuit for generating a hold signal, SW, for operating the hold switch to couple the integrating amplifier to the detector element during a predetermined interval of the detector current.

Photo acoustic detector with improved signal processing

Conventional accelerometers are based on test masses that are suspended in some kind of spring damper system. According to an exemplary embodiment of the present invention, a two-dimensional adaptive accelerometer based on dielectrophoresis is provided, which measures an acceleration of a test mass freely floating in a medium by determining the movement of the test mass due to an accelerating force acting on the test mass. A non-uniform electric force field provides for a wide and adjustable dynamic range.

Two-dimensional adaptive accelerometer based on dielectrophoresis

An oscillator element is provided, e.g., for use in a photo acoustic detector for detecting a concentration of a sample in a sample mixture using a light beam for excitation of molecules of the sample in proximity of an excitation area of the oscillator element. The oscillator element includes piezoelectric material for generating a voltage when mechanically distorted. Electrodes at least partially cover a surface of the oscillator element for detecting the generated voltage. The excitation area is arranged in such a way that heating of the electrodes in the excitation area by the light beam is avoided.

Oscillator element for photo acoustic detector

A controllable optical lens system, comprises a chamber housing first and second fluids, the interface between the fluids defining a lens surface. An electrode arrangement controls the shape of the lens surface and has first and second electrodes. A parameter is determined by the system dependent on the electrical resistance through at least one of the lens fluids between the first and second electrodes. Thus, the series resistance through a lens fluid is used as a measure of meniscus position.

Controllable optical lens

A controllable electrowetting lens system has a feedback control loop for controlling the electrode arrangement drive signals to implement an autofocus function. The feedback control loop comprising an image analysis focus detection system and a variable gain element. The gain is adjusted based on the lens condition, for example as sensed by a capacitance sensing arrangement. The autofocus control loop can be optimized to the lens characteristics (because the lens characteristics change over time) and/or to external conditions such as temperature.

The present invention discloses an optical device comprising a container enclosing an insulating liquid (A) and an electrically susceptible liquid (B), the insulating liquid (A) and the electrically susceptible liquid (B) being immiscible and being in contact with each other via an interface (), at least one of the liquids (A; B) being at least partially placed in a light path through the container. The optical device further comprises heating means () that preferably are responsive to a temperature sensor () for heating the insulating liquid (A) and the electrically susceptible liquid (B). Consequently, an optical device is obtained in which the influence of the temperature dependence of the physical properties of the insulating liquid (A) and the electrically susceptible liquid (B) on the behavior of the optical device is reduced, thus yielding an optical device with improved optical characteristics at low temperatures.

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Herten, Netherlands

Ivon Franciscus Helwegen