Microheater

About: Microheater is a research topic. Over the lifetime, 814 publications have been published within this topic receiving 12478 citations.

Fabrication of polymer Fabry-Perot fiber sensors using optical fiber microheaters

Abstract: We report on a novel fabrication technique for polymer based Fabry-Perot (F-P) optical fiber sensors. The F-P interferometers are based on microbubbles generated in the polymer by means of a microheater fiber probe. Upon inserting the probe and a cleaved single-mode fiber in a capillary tube containing the polymer, a microbubble can be readily generated which can serve as a reflective surface. A F-P cavity is thus formed by the microbubble and the single-mode fiber tip and temperature or strain deforming the bubble can be detected upon monitoring the FP resonances. The fabrication and performance of these devices as a temperature sensor is presented in this paper.

Method and apparatus to manufacture optical fiber coupler

Abstract: PROBLEM TO BE SOLVED: To obtain a method and an apparatus to manufacture a highly precise optical fiber coupler in which three or more optical fibers, which are arranged close to each other in a parallel manner, are fusion processed by uniformly heating them with a microheater so as to put them in a stretched state with no irregularity. SOLUTION: The manufacturing method consists of a setting process in which at least three or more optical fibers whose cover is removed are inserted into a heater from the opening section of the microheater and are arranged in a parallel manner in a direction orthogonal or approximately orthogonal to the opening section and a heating and fusing process in which the microheater is moved back and forth in the axial center direction of the optical fibers whose number is equal to or greater than three with a prescribed width size after the setting process so as to heat and to fuse the optical fibers and to stretch the optical fibers in the axial center direction. COPYRIGHT: (C)2005,JPO&NCIPI

Characterization of the thermal transients of an Ultra Low Power micromachined sensor

Abstract: This paper describes an embedded system for the simultaneous dynamic control and thermal characterization of the heating phase of an Ultra Low Power (ULP) micromachined sensor, featuring thermal characteristics quite similar to those of innovative ULP semiconducting metal oxide (MOX) sensors. A Pulse Width Modulated (PWM) powering system has been realized using a microcontroller featuring an ARM7 core to characterize the thermal behavior of a device formed by a Pt microheater and a Pt temperature sensor, over an insulating membrane. Two operating modes, namely constant target heater resistance and constant heating power, were implemented. The aim was to analyze the relation between heating period and operating temperature, to observe the thermal time constants of the device and the total thermal conductance. Repeatability of experimental results was assessed by guaranteeing the standard deviation of the controlled temperature was within ±5.5°C in worst case conditions. Experimental results show quantitatively a unique time constant τ both for the heater and the T-sensor, that changes dependently on the temperature rise ΔT between the ambient and the operating temperature in a range from 2 ms to 2.4 ms. The dependence of the operating temperature of such ULP micromachined systems on the frequency and duty cycle of the PWM signal was also characterized and guidelines for minimizing the temperature ripple were defined. Finally, we observed that in the chosen operating temperature range the thermal conductance is a linear function of the heating power.

Novel microthermal sensor principle for determining the mixture ratio of binary fluid mixtures using Föppl vortices

Abstract: . A novel sensor principle for determining binary fluid mixtures of known components is presented, making use of different thermal and rheological properties of the mixture's components. Using a microheater, a heat pulse is introduced in the mixture. The resulting temperature increase depends on the thermal properties of the mixture, allowing determination of the mixture ratio. Placing a bluff body in the fluid channel causes the formation of a stationary pair of vortices behind the body. The length of the vortex pair depends on the mixture's viscosity and thus its composition. By placing the microheater in the vortex area and making use of forced convection which changes with the size of the vortex, the sensitivity for determination of the mixture ratio can be increased by a factor of 2.5 compared to the direct thermal measurement. The flow velocity is measured independently of the mixture ratio using time-of-flight thermal anemometry.

Real Time Temperature Distribution Measurement of a Microheater by Using Off-Axis Digital Holography

Abstract: We describe a single shot off-axis digital holography based on a Mach-Zehnder interferometic scheme for measuring temperature distribution of a microheater. The proposed scheme has the capability of reconstructing object phase image which is dependent of the temperature distribution in real time. Experimental results shows that there is a moderate linear relationship between the measured phase and temperature in the range of 20℃ to 60℃. We expect that the proposed system can provide a very reliable and fast solution in various surface temperature distribution measurement applications.